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Baloxavir marboxil is an orally available prodrug of baloxavir acid. Japan was the first country to approve baloxavir marboxil as a treatment for influenza. The antiviral mechanism of action of baloxavir is unique; the drug blocks initiation of viral mRNA synthesis, thus preventing proliferation of the influenza virus. A single oral dose of baloxavir is usually well tolerated; it hastens alleviation of influenza symptoms and shortens the duration of viral shedding. However, novel influenza variants exhibiting over 10-fold reductions in baloxavir susceptibility emerged in baloxavir-treated patients. Although further clinical investigation is required to explore this issue, baloxavir may revolutionize our understanding of influenza virus biology.
Is Baloxavir effective for influenza?
A single oral dose of baloxavir is usually well tolerated; it hastens alleviation of influenza symptoms and shortens the duration of viral shedding.
Pharmacogenetic testing for HLA-B*5701 is cost-effective only if abacavir-based treatment is as effective and costs less than tenofovir-based treatment.
Which pharmacogenetic test is available for abacavir?
Pharmacogenetic testing for HLA-B*5701 is cost-effective only if abacavir-based treatment is as effective and costs less than tenofovir-based treatment.
Neonates do experience pain and its management is necessary in order to prevent long-term, as well as, short-term effects. The most common source of pain in the neonatal intensive care unit (NICU) is caused by medically invasive procedures. NICU patients have to endure trauma, medical adhesive related skin injuries, heel lance, venipuncture and intramuscular injection as well as nasogastric catheterization besides surgery. A cornerstone in pain assessment is the use of scales such as COMFORT, PIPP-R, NIPS and N-PASS. This narrative review provides an up to date account of neonate pain management used in NICUs worldwide focusing on non-pharmacological methods. Non-steroidal anti-inflammatory drugs have well established adverse side effects and opioids are addictive thus pharmacological methods should be avoided if possible at least for mild pain management. Non-pharmacological interventions, particularly breastfeeding and non-nutritive sucking as primary strategies for pain management in neonates are useful strategies to consider. The best non-pharmacological methods are breastfeeding followed by non-nutritive sucking coupled with sucrose sucking. Regrettably most parents used only physical methods and should be trained and involved for best results. Further research in NICU is essential as the developmental knowledge changes and neonate physiology is further uncovered together with its connection to pain.
What are the most common pain scales used to measure pain in neonates?
A cornerstone in pain assessment is the use of scales such as COMFORT, PIPP-R, NIPS and N-PASS.
Sumoylation is a post-translational modification that plays an important role in a wide range of cellular processes. Among the proteins involved in the sumoylation pathway, Ubc9 is the sole E2-conjugating enzyme required for sumoylation and plays a central role by interacting with almost all of the partners required for sumoylation. Ubc9 has been implicated in a variety of human malignancies. In order to exploit the therapeutic potential of Ubc9, we have identified the potential site to target for rational drug design using molecular modeling approaches. The structural information derived was then used to prioritize hits from a small-molecule library for biological assay using a virtual screening protocol that involves shape matching with a known inhibitor inhibitors and docking of a small-molecule library utilizing computational approaches that incorporate both ligand and protein flexibility. Nineteen compounds were acquired from different chemical vendors and were tested for Ubc9 inhibitory activity. Five compounds showed inhibitory activity against Ubc9, out of which one compound was selected for further optimization. A similarity search was then carried out to retrieve commercially available derivatives, which were further acquired and assayed, resulting in two compounds with acceptable potency. These two compounds can be used as starting points for the development of more potent inhibitors of Ubc9 targeting the predicted site.
What is the role of the UBC9 enzyme in the protein sumoylation pathway?
Among the proteins involved in the sumoylation pathway, Ubc9 is the sole E2-conjugating enzyme required for sumoylation and plays a central role by interacting with almost all of the partners required for sumoylation.
DNA double-strand breaks (DSBs) can induce chromosomal aberrations and carcinogenesis and their correct repair is crucial for genetic stability. The cellular response to DSBs depends on damage signaling including the phosphorylation of the histone H2AX (γH2AX). However, a lack of γH2AX formation in heterochromatin (HC) is generally observed after DNA damage induction. Here, we examine γH2AX and repair protein foci along linear ion tracks traversing heterochromatic regions in human or murine cells and find the DSBs and damage signal streaks bending around highly compacted DNA. Given the linear particle path, such bending indicates a relocation of damage from the initial induction site to the periphery of HC. Real-time imaging of the repair protein GFP-XRCC1 confirms fast recruitment to heterochromatic lesions inside murine chromocenters. Using single-ion microirradiation to induce localized DSBs directly within chromocenters, we demonstrate that H2AX is early phosphorylated within HC, but the damage site is subsequently expelled from the center to the periphery of chromocenters within ∼ 20 min. While this process can occur in the absence of ATM kinase, the repair of DSBs bordering HC requires the protein. Finally, we describe a local decondensation of HC at the sites of ion hits, potentially allowing for DSB movement via physical forces.
What happens to H2AX upon DNA bouble strand breaks?
he cellular response to DSBs depends on damage signaling including the phosphorylation of the histone H2AX (γH2AX). However, a lack of γH2AX formation in heterochromatin (HC) is generally observed after DNA damage induction. Here, we examine γH2AX and repair protein foci along linear ion tracks traversing heterochromatic regions in human or murine cells and find the DSBs and damage signal streaks bending around highly compacted DNA.
Transcript elongation can be interrupted by a variety of obstacles, including certain DNA sequences, DNA-binding proteins, chromatin, and DNA lesions. Bypass of many of these impediments is facilitated by elongation factor TFIIS through a mechanism that involves cleavage of the nascent transcript by the RNA polymerase II/TFIIS elongation complex. Highly purified yeast RNA polymerase II is able to perform transcript hydrolysis in the absence of TFIIS. The "intrinsic" cleavage activity is greatly stimulated at mildly basic pH and requires divalent cations. Both arrested and stalled complexes can carry out the intrinsic cleavage reaction, although not all stalled complexes are equally efficient at this reaction. Arrested complexes in which the nascent transcript was cleaved in the absence of TFIIS were reactivated to readthrough blocks to elongation. Thus, cleavage of the nascent transcript is sufficient for reactivating some arrested complexes. Small RNA products released following transcript cleavage in stalled ternary complexes differ depending upon whether the cleavage has been induced by TFIIS or has occurred in mildly alkaline conditions. In contrast, both intrinsic and TFIIS-induced small RNA cleavage products are very similar when produced from an arrested ternary complex. Although alpha-amanitin interferes with the transcript cleavage stimulated by TFIIS, it has little effect on the intrinsic cleavage reaction. A mutant RNA polymerase previously shown to be refractory to TFIIS-induced transcript cleavage is essentially identical to the wild type polymerase in all tested aspects of intrinsic cleavage.
Which RNA polymerase II subunit carries RNA cleavage activity?
Highly purified yeast RNA polymerase II is able to perform transcript hydrolysis in the absence of TFIIS.
A cis-acting DNA regulatory element 3' to the A gamma-globin gene contains eight distinct regions of DNA-protein interaction distributed over 750 bp of DNA. The sequences of two foot-printed regions (sites I and IV) are A-T rich and generate a highly retarded complex on gel shift analysis with nuclear extract from human erythroleukemia (K562) cells. We have purified a 98-kD protein that reproduces this gel shift. Tryptic cleavage and peptide sequence analysis demonstrated that the 98-kD protein is identical to a recently cloned protein, special A-T-rich binding protein 1 (SATB1), that binds selectively to nuclear matrix/scaffold-associated regions of DNA (MARs/SARs). We have shown by functional analysis that the 3' A gamma regulatory element associates with the nuclear matrix. SATB1 mRNA was identified in K562 cells, and reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated its transcript in several other hematopoietic lines. Antisera to SATB1 caused ablation of the gel shift complex generated by both the crude nuclear extract and the purified 98-kD protein with the site I oligonucleotide. Furthermore, oligonucleotides that bind SATB1 inhibited formation of the site I gel shift complex when added as excess unlabeled competitor. An immunoblot analysis of the site I gel shift complex documented the presence of SATB1. Binding of SATB1 to two sites within the 3' A gamma regulatory element and its MAR/SAR activity suggests that this element may influence gene expression through interaction with the nuclear matrix.
Is SATB1 positioned close to AT-rich sequences?
Tryptic cleavage and peptide sequence analysis demonstrated that the 98-kD protein is identical to a recently cloned protein, special A-T-rich binding protein 1 (SATB1)
The Muenke syndrome (MS) is characterized by unicoronal or bicoronal craniosynostosis, midfacial hypoplasia, ocular hypertelorism, and a variety of minor abnormalities associated with a mutation in the fibroblast growth factor receptor 3 (FGFR3) gene. The birth prevalence is approximately one in 10,000 live births, accounting for 8-10% of patients with coronal synostosis. Although MS is a relatively common diagnosis in patients with craniosynostosis syndromes, with autosomal dominant inheritance, there has been no report of MS, in an affected Korean family with typical cephalo-facial morphology that has been confirmed by molecular studies. Here, we report a familial case of MS in a female patient with a Pro250Arg mutation in exon 7 (IgII-IGIII linker domain) of the FGFR3 gene. This patient had mild midfacial hypoplasia, hypertelorism, downslanting palpebral fissures, a beak shaped nose, plagio-brachycephaly, and mild neurodevelopmental delay. The same mutation was confirmed in the patient's mother, two of the mother's sisters and the maternal grandfather. The severity of the cephalo-facial anomalies was variable among these family members.
What symptoms characterize the Muenke syndrome?
The Muenke syndrome (MS) is characterized by unicoronal or bicoronal craniosynostosis, midfacial hypoplasia, ocular hypertelorism, and a variety of minor abnormalities associated with a mutation in the fibroblast growth factor receptor 3 (FGFR3) gene.
1. Sometimes called "lazy eye," amblyopia is poor vision in an eye that did not develop normal sight during early childhood. Amblyopia is common, affecting approximately 2 or 3 out of every 100 people. The best time to correct amblyopia is during infancy or early childhood. 2. Amblyopia has three major causes: strabismus (misaligned eyes), unequal focus (refractive error), and cloudiness in the normally clear eye tissues. 3. To correct amblyopia, a child must be made to use the weak eye. This is usually done by patching or covering the strong eye. Amblyopia cannot be cured by treating the cause alone; the weaker eye must be made stronger in order to see normally.
Does Amblyopia affect the eye?
To correct amblyopia, a child must be made to use the weak eye.
A chemical screen designed to identify novel inducers of autophagy led to the discovery that signal transducer and activator of transcription 3 (STAT3) inhibitors can potently stimulate the autophagic flux. Although STAT3 is best known as a pro-inflammatory and oncogenic transcription factor, mechanistic analyses revealed that autophagy is regulated by the cytoplasmic, not nuclear, pool of STAT3. Cytoplasmic STAT3 normally interacts with the eukaryotic translation initiation factor 2, subunit 1α, 35kDa (EIF2S1/eIF2α) kinase 2/protein kinase, RNA-activated (EIF2AK2/PKR), a sensor of double-stranded RNA. This interaction, which could be recapitulated using recombinant proteins in pull-down experiments, involves the catalytic domain of EIF2AK2 as well as the SH2 domain of STAT3, which can adopt a fold similar to that of EIF2S1. Thus, STAT3 may act as a competitive inhibitor of EIF2AK2. Indeed, pharmacological or genetic inhibition of STAT3 stimulates EIF2AK2-dependent EIF2S1 phosphorylation and autophagy. Conversely, the overexpression of wild-type STAT3 as well as of STAT3 mutants that cannot be phosphorylated by JAK2 or are excluded from the nucleus inhibits autophagy. However, STAT3 mutants that fail to interact with EIF2AK2 are unable to suppress autophagy. Both STAT3-targeting agents (i.e., Stattic, JSI-124 and WP1066) and EIF2AK2 activators (such as the double-strand RNA mimetic polyinosinic:polycytidylic acid) are capable of disrupting the inhibitory interaction between STAT3 and EIF2AK2 in cellula, yet only the latter does so in cell-free systems in vitro. A further screen designed to identify EIF2AK2-dependent autophagy inducers revealed that several fatty acids including palmitate trigger autophagy via a pathway that involves the disruption of the STAT3-EIF2AK2 complex as well as the phosphorylation of mitogen-activated protein kinase 8/c-Jun N-terminal kinase 1 (MAPK8/JNK1) and EIF2S1. These results reveal an unsuspected crosstalk between cellular metabolism (fatty acids), pro-inflammatory signaling (STAT3), innate immunity (EIF2AK2), and translational control (EIF2S1) that regulates autophagy.
Is STAT3 involved in EIF2AK2-dependent suppression of autophagy?
These results reveal an unsuspected crosstalk between cellular metabolism (fatty acids), pro-inflammatory signaling (STAT3), innate immunity (EIF2AK2), and translational control (EIF2S1) that regulates autophagy
The H1N1 2009 virus is pandemic in many countries. The genome of this virus contains eight segments. Among the eight segments maximum numbers of mutation occur at the segment 1 and segment 4 which codes for PB2 subunit and hemagglutinin (HA) and less number of mutations occur in segment 6 which codes for neuraminidase (NA) protein. Neuraminidase (NA) inhibitors (Oseltamivir and Zanamivir) are presently used as an anti-flu drugs. In the present study, the in silico efficacy of different drugs was tested against the swine flu virus. 3D structures of neuraminidase (NA) proteins of H1N1 2009 were generated using Geno3D. The 3D structure of H1N1 1918 was downloaded from PDB. Interaction study was done using Arguslab 4 and PyMol view. Oseltamivir and Zanamivir have good number of interactions with H1N1 2009 virus and the scoring function also support to this result. When compared with the 1918 H1N1 viral protein, 2009 H1N1 NA protein shows more number of interaction and good scoring function. The RMSD value of before and after docking are found to be same at 0.04A° for both the drugs. The force field energy of NA protein 2009 was found to be -15603.529 KJ/mol before docking. The force field energy was found to be decreased after docking at -17620.740 KJ/mol with Tamiflu and -17652.242 KJ/mol with Zanamivir. The number of interaction and scoring function shows that Oseltamivir and Zanamivir will be able to effectively control the present pandemic H1N1 virus 2009.
What is the function of Oseltamivir when administered during flu?
Neuraminidase (NA) inhibitors (Oseltamivir and Zanamivir) are presently used as an anti-flu drugs.
Care for patients with Duchenne muscular dystrophy (DMD) is poorly standardised. There are many interventions in different systems which are known to improve outcomes in DMD but these are not uniformly applied. This leads to inequality in access to treatment, as well as problems for planning controlled trials of future therapeutics. A worldwide effort is underway to generate care guidelines for DMD, which involves the Centre for Disease Control in the USA and the TREAT-NMD network of excellence for neuromuscular diseases in Europe. In advance of the full consensus document, TREAT-NMD has worked on the generation of brief standards of care for DMD, which are presented here and are available via the TREAT-NMD website (http://www.treat-nmd.eu). Guidelines are presented for diagnostics, neurological follow up, gastrointestinal and nutritional issues, respiratory and cardiac care as well as orthopaedics, rehabilitation, psychosocial interventions and oral care.
Elaborate on the TREAT-NMD initiative for DMD patients
In advance of the full consensus document, TREAT-NMD has worked on the generation of brief standards of care for DMD, which are presented here and are available via the TREAT-NMD website (http://www.treat-nmd.eu). Guidelines are presented for diagnostics, neurological follow up, gastrointestinal and nutritional issues, respiratory and cardiac care as well as orthopaedics, rehabilitation, psychosocial interventions and oral care.
Netherton syndrome is a severe autosomal recessive skin disorder characterized by congenital erythroderma, a specific hair-shaft abnormality, and atopic manifestations with high IgE levels. Recently, we identified SPINK5, which encodes the serine protease inhibitor Kazal-type 5 protein (LEKTI), as the defective gene in Netherton syndrome. Here we describe the intron-exon organization of the gene and characterize the SPINK5 mutations in patients from 21 families of different geographic origin, using denaturing high performance liquid chromatography and direct sequencing. We identified 18 mutations, of which 13 were novel and seven (39%) were recurrent. The majority of the mutations were clustered between exons 1-8 and exons 21-26. They comprised four nonsense mutations (22%), eight frameshift insertions or deletions (44%), and six splice-site defects (33%). All mutations predict the formation of premature termination codons. Northern blot analysis showed variable reduction of SPINK5 mutant transcript levels, suggesting variable efficiency of nonsense-mediated mRNA decay. Seven patients were homozygotes, eight were compound heterozygotes, and five were heterozygotes with only one identifiable SPINK5 mutation. Five mutations, one of which resulted in perinatal lethal disease in three families, were associated with certain ethnic groups. We also describe 45 intragenic polymorphisms in the patients studied. The clinical features of erythroderma, trichorrhexis invaginata, and atopic manifestations were present in the majority of affected individuals and ichthyosis linearis circumflexa was seen in 12 out of 24 patients. Interfamilial and intrafamilial variation in disease severity was observed, with no clear correlation between mutations and phenotype, suggesting that the degree of severity may be affected by other factors.
Mutations in which gene and which protein are associated with Netherton syndrome?
Recently, we identified SPINK5, which encodes the serine protease inhibitor Kazal-type 5 protein (LEKTI), as the defective gene in Netherton syndrome. Here we describe the intron-exon organization of the gene and characterize the SPINK5 mutations in patients from 21 families of different geographic origin, using denaturing high performance liquid chromatography and direct sequencing.
Genome editing has attracted wide interest for the generation of cellular models of disease using human pluripotent stem cells and other cell types. CRISPR-Cas systems and TALENs can target desired genomic sites with high efficiency in human cells, but recent publications have led to concern about the extent to which these tools may cause off-target mutagenic effects that could potentially confound disease-modeling studies. Using CRISPR-Cas9 and TALEN targeted human pluripotent stem cell clones, we performed whole-genome sequencing at high coverage in order to assess the degree of mutagenesis across the entire genome. In both types of clones, we found that off-target mutations attributable to the nucleases were very rare. From this analysis, we suggest that, although some cell types may be at risk for off-target mutations, the incidence of such effects in human pluripotent stem cells may be sufficiently low and thus not a significant concern for disease modeling and other applications.
Is TALEN being used on stem cells?
Using CRISPR-Cas9 and TALEN targeted human pluripotent stem cell clones, we performed whole-genome sequencing at high coverage in order to assess the degree of mutagenesis across the entire genome.
TAL1/SCL (hereafter referred to as TAL1) is a critical transcription factor required for hematopoiesis in which hematopoietic stem cells commit and differentiate to different lineages. During this process, transcription of many genes is turned on and off in part by epigenetic mechanisms. TAL1 has recently been shown to differentially recruit LSD1 and other histone modifying complexes to regulate its target genes. Here, we focus primarily on epigenetic mechanisms that are regulated by TAL1 during normal and malignant hematopoiesis. We discuss how different histone modifying enzymes are recruited by TAL1 and how these enzymatic activities mediate the activating or repressive function of TAL1. Finally, we further explore the possible mechanisms by which dysregulation of the recruitment and activity of histone modifying enzymes contribute to leukemogenesis.
What is the role of lysine-specific demethylase 1 (LSD1) in hematopoiesis?
TAL1 has recently been shown to differentially recruit LSD1 and other histone modifying complexes to regulate its target genes
Previous work has demonstrated that fusion of a luciferase to an opsin, to create a luminescent opsin or luminopsin, provides a genetically encoded means of manipulating neuronal activity via both chemogenetic and optogenetic approaches. Here we have expanded and refined the versatility of luminopsin tools by fusing an alternative luciferase variant with high light emission, Gaussia luciferase mutant GLucM23, to depolarizing and hyperpolarizing channelrhodopsins with increased light sensitivity. The combination of GLucM23 with Volvox channelrhodopsin-1 produced LMO4, while combining GLucM23 with the anion channelrhodopsin iChloC yielded iLMO4. We found efficient activation of these channelrhodopsins in the presence of the luciferase substrate, as indicated by responses measured in both single neurons and in neuronal populations of mice and rats, as well as by changes in male rat behavior during amphetamine-induced rotations. We conclude that these new luminopsins will be useful for bimodal opto- and chemogenetic analyses of brain function.
Are Luminopsins a fusion proteins of luminol and Rhodopsin ?
Here we have expanded and refined the versatility of luminopsin tools by fusing an alternative luciferase variant with high light emission, Gaussia luciferase mutant GLucM23, to depolarizing and hyperpolarizing channelrhodopsins
Miller Fisher syndrome (MFS), a variant of Guillain-Barré syndrome, is a rare disorder typically characterized by a triad of ataxia, areflexia, and ophthalmoplegia, which may have a highly variable clinical presentation. We report a case of MFS in a 45-year-old female presenting with sphenoid sinusitis and sixth nerve palsy. She underwent endoscopic sphenoid sinusotomy without improvement, had postoperative deterioration, was diagnosed with MFS, and was treated with intravenous immunoglobulin with complete response. Because of the potential severity of Guillain-Barré syndrome, great vigilance should be taken when examining sixth nerve palsies to prevent misdiagnosis and delay in treatment of the MFS variant of this disease.
Is the Miller-Fisher syndrome considered to be a variant of Guillain-Barré?
Miller Fisher syndrome (MFS), a variant of Guillain-Barré syndrome, is a rare disorder typically characterized by a triad of ataxia, areflexia, and ophthalmoplegia, which may have a highly variable clinical presentation.
Feline coronavirus (FCoV) is an etiological agent that causes a benign enteric illness and the fatal systemic disease feline infectious peritonitis (FIP). The FCoV spike (S) protein is considered the viral regulator for binding and entry to the cell. This protein is also involved in FCoV tropism and virulence, as well as in the switch from enteric disease to FIP. This regulation is carried out by spike's major functions: receptor binding and virus-cell membrane fusion. In this review, we address important aspects in FCoV genetics, replication and pathogenesis, focusing on the role of S. To better understand this, FCoV S protein models were constructed, based on the human coronavirus NL63 (HCoV-NL63) S structure. We describe the specific structural characteristics of the FCoV S, in comparison with other coronavirus spikes. We also revise the biochemical events needed for FCoV S activation and its relation to the structural features of the protein.
The virus that causes FIP, Feline Infectious Peritonitis belongs to what family?
Feline coronavirus (FCoV) is an etiological agent that causes a benign enteric illness and the fatal systemic disease feline infectious peritonitis (FIP).
Atrial fibrillation is the most common arrhythmia worldwide with increasing frequency noted with age. Hyperthyroidism is a well-known cause of atrial fibrillation with a 16%-60% prevalence of atrial fibrillation in patients with known hyperthyroidism Ross et al. (2016). While hyperthyroidism as a causative factor of atrial fibrillation is well established, this literature review aims to answer several questions on this topic including: 1. The relationship of atrial fibrillation to hyperthyroidism 2. Atrial fibrillation as a predictor of hyperthyroidism 3. The pathophysiology of thyrotoxic atrial fibrillation 4. Subclinical hyperthyroidism and the relationship with atrial fibrillation 5. Cardioversion and Catheter ablation of hyperthyroid patients with atrial fibrillation 6. Thrombotic risk of hyperthyroid patients with atrial fibrillation 7. Management of Thyrotoxic Atrial fibrillation 8. Pharmacological rhythm control in patients with hyperthyroidism and atrial fibrillation 9. Treatment of Hyperthyroidism to prevent atrial fibrillation 10. Clinical Implications of Hyperthyroidism and Atrial Fibrillation.
Please list 10 conditions which play a role in causing atrial fibrillation.
Atrial fibrillation is the most common arrhythmia worldwide with increasing frequency noted with age. Hyperthyroidism is a well-known cause of atrial fibrillation with a 16%-60% prevalence of atrial fibrillation in patients with known hyperthyroidism
miR-1 levels are greatly reduced in human AF, possibly contributing to up-regulation of Kir2.1 subunits, leading to increased I(K1). Because up-regulation of inward-rectifier currents is important for AF maintenance, these results provide potential new insights into molecular mechanisms of AF with potential therapeutic implications.
Is micro RNA 1 (miR-1) implicated in cardiac arrhythmias?
miR-1 levels are greatly reduced in human AF, possibly contributing to up-regulation of Kir2.1 subunits, leading to increased I(K1). Because up-regulation of inward-rectifier currents is important for AF maintenance, these results provide potential new insights into molecular mechanisms of AF with potential therapeutic implications.
Nearly 30 years have elapsed since Rowe and Weller and their colleagues discovered human cytomegalovirus (CMV). Because of its complex structure, long replicative cycle, low yield in vitro, and highly species-specific cell-substrate requirement, the cellular and molecular biologic analyses of human CMV have been slow, but recombinant DNA and monoclonal antibody technologies are bringing about rapid changes. Because of the long period of latency and wide range of disease presentations, epidemiologic and medical insights have also come slowly. However, the clinical events that occur during iatrogenic immunosuppression (transplantation and cancer therapy) and as a result of immunocompromise due to human immunodeficiency virus infection are currently promoting our understanding of the epidemiology of CMV disease and the definition of its clinical spectrum. Rapid diagnostic methods, antiviral drugs, and vaccines for CMV are becoming available. We may not yet understand completely the impact of this agent on the nonimmunosuppressed or aspects of its pathogenesis: e.g., the immune functions controlling recrudescence and the possibility of increased disease severity in those with no detectable immune defect. With the availability of new approaches, other issues should be clarified, such as the functions of host and virus involved in the mechanism of persistence.
Can you define iatrogenic disease?
However, the clinical events that occur during iatrogenic immunosuppression (transplantation and cancer therapy) and as a result of immunocompromise due to human immunodeficiency virus infection are currently promoting our understanding of the epidemiology of CMV disease and the definition of its clinical spectrum
The orexin (also known as hypocretin) G protein-coupled receptors (GPCRs) respond to orexin neuropeptides in the central nervous system to regulate sleep and other behavioural functions in humans. Defects in orexin signalling are responsible for the human diseases of narcolepsy and cataplexy; inhibition of orexin receptors is an effective therapy for insomnia. The human OX2 receptor (OX2R) belongs to the β branch of the rhodopsin family of GPCRs, and can bind to diverse compounds including the native agonist peptides orexin-A and orexin-B and the potent therapeutic inhibitor suvorexant. Here, using lipid-mediated crystallization and protein engineering with a novel fusion chimaera, we solved the structure of the human OX2R bound to suvorexant at 2.5 Å resolution. The structure reveals how suvorexant adopts a π-stacked horseshoe-like conformation and binds to the receptor deep in the orthosteric pocket, stabilizing a network of extracellular salt bridges and blocking transmembrane helix motions necessary for activation. Computational docking suggests how other classes of synthetic antagonists may interact with the receptor at a similar position in an analogous π-stacked fashion. Elucidation of the molecular architecture of the human OX2R expands our understanding of peptidergic GPCR ligand recognition and will aid further efforts to modulate orexin signalling for therapeutic ends.
What molecule is targeted by suvorexant?
The human OX2 receptor (OX2R) belongs to the β branch of the rhodopsin family of GPCRs, and can bind to diverse compounds including the native agonist peptides orexin-A and orexin-B and the potent therapeutic inhibitor suvorexant.
Cohesin regulates sister chromatid cohesion during the mitotic cell cycle with Nipped-B-Like (NIPBL) facilitating its loading and unloading. In addition to this canonical role, cohesin has also been demonstrated to play a critical role in regulation of gene expression in nondividing cells. Heterozygous mutations in the cohesin regulator NIPBL or cohesin structural components SMC1A and SMC3 result in the multisystem developmental disorder Cornelia de Lange Syndrome (CdLS). Genome-wide assessment of transcription in 16 mutant cell lines from severely affected CdLS probands has identified a unique profile of dysregulated gene expression that was validated in an additional 101 samples and correlates with phenotypic severity. This profile could serve as a diagnostic and classification tool. Cohesin binding analysis demonstrates a preference for intergenic regions suggesting a cis-regulatory function mimicking that of a boundary/insulator interacting protein. However, the binding sites are enriched within the promoter regions of the dysregulated genes and are significantly decreased in CdLS proband, indicating an alternative role of cohesin as a transcription factor.
What is the function of the NIPBL factor in genome conformation?
Cohesin regulates sister chromatid cohesion during the mitotic cell cycle with Nipped-B-Like (NIPBL) facilitating its loading and unloading
Are its level found to increase or to decrease?
The ability of Frzb/secreted Frizzled-related protein 3 (sFRP3) to inhibit Wnt signaling and the localization of Frzb/sFRP3 on chromosome 2q to a region frequently deleted in cancers have led some investigators to hypothesize that Frzb/sFRP3 is a tumor suppressor gene.
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Does an activated oncogene that initiates tumor growth need to remain activated to maintain the cancer phenotype? This question has been answered affirmatively by experiments in which doxycycline-regulated oncogene activation induces growth of large tumors that regress completely upon oncogene inactivation--a phenomenon called oncogene addiction. We assemble here the evidence that oncogene addiction is angiogenesis-dependent. Although activated oncogenes increase tumor cell proliferation and decrease their apoptosis, these activities are not sufficient to expand tumor mass beyond a microscopic size. Oncogenes must also induce tumor angiogenesis for expansion of tumor mass. We propose experiments to validate the "endothelial centric" hypothesis of oncogene addiction.
Which phenomenon is described as oncogene addiction?
Does an activated oncogene that initiates tumor growth need to remain activated to maintain the cancer phenotype? This question has been answered affirmatively by experiments in which doxycycline-regulated oncogene activation induces growth of large tumors that regress completely upon oncogene inactivation--a phenomenon called oncogene addiction.
The PLA2G6 gene encodes a group VIA calcium-independent phospholipase A2 beta enzyme that selectively hydrolyses glycerophospholipids to release free fatty acids. Mutations in PLA2G6 have been associated with disorders such as infantile neuroaxonal dystrophy, neurodegeneration with brain iron accumulation type II and Karak syndrome. More recently, PLA2G6 was identified as the causative gene in a subgroup of patients with autosomal recessive early-onset dystonia-parkinsonism. Neuropathological examination revealed widespread Lewy body pathology and the accumulation of hyperphosphorylated tau, supporting a link between PLA2G6 mutations and parkinsonian disorders. Here we show that knockout of the Drosophila homologue of the PLA2G6 gene, iPLA2-VIA, results in reduced survival, locomotor deficits and organismal hypersensitivity to oxidative stress. Furthermore, we demonstrate that loss of iPLA2-VIA function leads to a number of mitochondrial abnormalities, including mitochondrial respiratory chain dysfunction, reduced ATP synthesis and abnormal mitochondrial morphology. Moreover, we show that loss of iPLA2-VIA is strongly associated with increased lipid peroxidation levels. We confirmed our findings using cultured fibroblasts taken from two patients with mutations in the PLA2G6 gene. Similar abnormalities were seen including elevated mitochondrial lipid peroxidation and mitochondrial membrane defects, as well as raised levels of cytoplasmic and mitochondrial reactive oxygen species. Finally, we demonstrated that deuterated polyunsaturated fatty acids, which inhibit lipid peroxidation, were able to partially rescue the locomotor abnormalities seen in aged flies lacking iPLA2-VIA gene function, and restore mitochondrial membrane potential in fibroblasts from patients with PLA2G6 mutations. Taken together, our findings demonstrate that loss of normal PLA2G6 gene activity leads to lipid peroxidation, mitochondrial dysfunction and subsequent mitochondrial membrane abnormalities. Furthermore we show that the iPLA2-VIA knockout fly model provides a useful platform for the further study of PLA2G6-associated neurodegeneration.
Which gene is mutated in the Karak syndrome?
Mutations in PLA2G6 have been associated with disorders such as infantile neuroaxonal dystrophy, neurodegeneration with brain iron accumulation type II and Karak syndrome
Phospholamban (PLN) is a key regulator of Ca(2+) homeostasis and contractility in the heart. Its regulatory effects are mediated through its interaction with the sarcoplasmic reticulum Ca(2+)-ATPase, (SERCA2a), resulting in alterations of its Ca(2+)-affinity. To identify additional proteins that may interact with PLN, we used the yeast-two-hybrid system to screen an adult human cardiac cDNA library. HS-1 associated protein X-1 (HAX-1) was identified as a PLN-binding partner. The minimal binding regions were mapped to amino acid residues 203-245 for HAX-1 and residues 16-22 for PLN. The interaction between the two proteins was confirmed using GST-HAX-1, bound to the glutathione-matrix, which specifically adsorbed native PLN from human or mouse cardiac homogenates, while in reciprocal binding studies, recombinant His-HAX-1 bound GST-PLN. Kinetic studies using surface plasmon resonance yielded a K(D) of approximately 1 muM as the binding affinity for the PLN/HAX-1 complex. Phosphorylation of PLN by cAMP-dependent protein kinase reduced binding to HAX-1, while increasing concentrations of Ca(2+) diminished the PLN/HAX-1 interaction in a dose-dependent manner. HAX-1 concentrated to mitochondria, but upon transient co-transfection of HEK 293 cells with PLN, HAX-1 redistributed and co-localized with PLN at the endoplasmic reticulum. Analysis of the anti-apoptotic function of HAX-1 revealed that the presence of PLN enhanced the HAX-1 protective effects from hypoxia/reoxygenation-induced cell death. These findings suggest a possible link between the Ca(2+) handling by the sarcoplasmic reticulum and cell survival mediated by the PLN/HAX-1 interaction.
Which protein has been found to interact with phospholamban (PLN) and is also an anti-apoptotic protein?
Analysis of the anti-apoptotic function of HAX-1 revealed that the presence of PLN enhanced the HAX-1 protective effects from hypoxia/reoxygenation-induced cell death. These findings suggest a possible link between the Ca(2+) handling by the sarcoplasmic reticulum and cell survival mediated by the PLN/HAX-1 interaction.
Lysozymes are an ancient group of antimicrobial enzymes of the innate immune system. Here we provide a comparative analysis of the evolution and function of lysozymes during early development in fish, the most speciose vertebrate group. In fishes, lineage and species-specific evolution of both C-type (chicken or conventional) and G-type (goose type) genes occurred. Phylogenetic analysis revealed that the teleost lysozyme G-type members group with the tetrapod homologues but the teleost C-type form three different clusters with the tetrapods. Most of the teleost C-type cluster with tetrapod Lyz but there are some that group with the mammalian Lyzl1/2 and LALBA. This suggests that early in gnathostome evolution these genes already existed and that lyzl1/2 and lalba genes are present in fish and tetrapods. Gene synteny analysis to confirm sequence orthologies failed to identify conserved genome regions between teleosts and other vertebrates lysozyme gene regions suggesting that in the ancestral bony fish genome lyz, lyzl1/2, lalba and lyg precursor genes were transposed to different chromosome regions. The homologue of the mammalian lactalbumin (LALBA) gene was identified for the first time in teleosts and was expressed in skin and during egg and larval development. Lysozyme activity was detected in teleost eggs and varied between species and in the gilthead sea bream lyg and lalba transcript abundance differed in eggs and larvae from different brood stock suggesting differences exist in maternal innate immune protection.
What is the function of lysozyme?
Lysozymes are an ancient group of antimicrobial enzymes of the innate immune system.
Phylogenetic reconstruction using molecular data is often subject to homoplasy, leading to inaccurate conclusions about phylogenetic relationships among operational taxonomic units. Compared with other molecular markers, single-nucleotide polymorphisms (SNPs) exhibit extremely low mutation rates, making them rare in recently emerged pathogens, but they are less prone to homoplasy and thus extremely valuable for phylogenetic analyses. Despite their phylogenetic potential, ascertainment bias occurs when SNP characters are discovered through biased taxonomic sampling; by using whole-genome comparisons of five diverse strains of Bacillus anthracis to facilitate SNP discovery, we show that only polymorphisms lying along the evolutionary pathway between reference strains will be observed. We illustrate this in theoretical and simulated data sets in which complex phylogenetic topologies are reduced to linear evolutionary models. Using a set of 990 SNP markers, we also show how divergent branches in our topologies collapse to single points but provide accurate information on internodal distances and points of origin for ancestral clades. These data allowed us to determine the ancestral root of B. anthracis, showing that it lies closer to a newly described "C" branch than to either of two previously described "A" or "B" branches. In addition, subclade rooting of the C branch revealed unequal evolutionary rates that seem to be correlated with ecological parameters and strain attributes. Our use of nonhomoplastic whole-genome SNP characters allows branch points and clade membership to be estimated with great precision, providing greater insight into epidemiological, ecological, and forensic questions.
How homoplasy affects phylogenetic reconstruction?
Phylogenetic reconstruction using molecular data is often subject to homoplasy, leading to inaccurate conclusions about phylogenetic relationships among operational taxonomic units.
A histological analysis was conducted in 138 female breast cancer patients, and the results were classified in accordance with "Histological Typing of Breast Tumours" (WHO, Geneva 1981). Since about half of these tumors showed more than one histological type of carcinoma, a simplified classification system with four groups was adopted. When patients were categorized according to the number and degree of kinship of their relatives with breast cancer, no specific association with the histological types was found. Familial tumors also encompassed a wide spectrum of histopathologic diagnoses. This suggests the absence of a histological marker in familial breast cancer. Pedigrees of all the patients were then analyzed, special emphasis being placed on relatives suffering from the same and other malignancies. It was found that 13.8% of the probands had at least one first-degree relative with breast cancer and that, compared with the tumor spectra in the male and female population, there was a significantly higher number of esophageal carcinomas in the fathers, of stomach cancers in the uncles and grandfathers, of brain tumors in the mothers, and of sarcomas in the brothers. An accumulation of the same tumors, especially stomach cancer and tumors related to the SBLA syndrome, was observed in families of index patients with tubular or medullary breast cancer. The SBLA syndrome is a complex familial cancer syndrome characterized by a proclivity to Sarcomas, Breast cancers, brain tumors, Lung and laryngeal cancers, leukemia, and Adrenocortical carcinomas.
List the cancers that are associated with SBLA syndrome.
The SBLA syndrome is a complex familial cancer syndrome characterized by a proclivity to Sarcomas, Breast cancers, brain tumors, Lung and laryngeal cancers, leukemia, and Adrenocortical carcinomas.
Intramural hematoma of the aorta is a condition increasingly observed in clinical practice. Uncertainty exists whether such lesions represent a different pathology or simply the precursors of classic dissecting aneurysm. The patient was a 76-year-old woman with intramural hematoma of the ascending aorta. Clinical course, progression of the lesion to type A aortic dissection, and surgical treatment are described. Although natural history of intramural hematoma of the ascending aorta is not clearly elucidated, the case presented confirms that the evolution toward intimal flap formation is possible and that we cannot foresee the stabilization of these lesions. We stress that intramural hematoma of the ascending aorta has to be managed as an aortic type A dissection and that aggressive treatment is advisable.
What is the most frequent evolution (next stage) when Aortic intramural hematoma (IMH) is not treated?
Intramural hematoma of the aorta is a condition increasingly observed in clinical practice. Uncertainty exists whether such lesions represent a different pathology or simply the precursors of classic dissecting aneurysm
The mechanism by which cells decide to skip mitosis to become polyploid is largely undefined. Here we used a high-content image-based screen to identify small-molecule probes that induce polyploidization of megakaryocytic leukemia cells and serve as perturbagens to help understand this process. Our study implicates five networks of kinases that regulate the switch to polyploidy. Moreover, we find that dimethylfasudil (diMF, H-1152P) selectively increased polyploidization, mature cell-surface marker expression, and apoptosis of malignant megakaryocytes. An integrated target identification approach employing proteomic and shRNA screening revealed that a major target of diMF is Aurora kinase A (AURKA). We further find that MLN8237 (Alisertib), a selective inhibitor of AURKA, induced polyploidization and expression of mature megakaryocyte markers in acute megakaryocytic leukemia (AMKL) blasts and displayed potent anti-AMKL activity in vivo. Our findings provide a rationale to support clinical trials of MLN8237 and other inducers of polyploidization and differentiation in AMKL.
Inhibition of which enzyme is mechanism of action of alisertib?
We further find that MLN8237 (Alisertib), a selective inhibitor of AURKA, induced polyploidization and expression of mature megakaryocyte markers in acute megakaryocytic leukemia (AMKL) blasts and displayed potent anti-AMKL activity in vivo.
The 3'-ends of both prokaryotic and eukaryotic mRNA are polyadenylated, but the poly(A) tracts of prokaryotic mRNA are generally shorter, ranging from 15 to 60 adenylate residues and associated with only 2-60% of the molecules of a given mRNA species. The sites of polyadenylation of bacterial mRNA are diverse and include the 3'-ends of primary transcripts, the sites of endonucleolytic processing in the 3' untranslated and intercistronic regions, and sites within the coding regions of mRNA degradation products. The diversity of polyadenylation sites suggests that mRNA polyadenylation in prokaryotes is a relatively indiscriminate process that can occur at all mRNA's 3'-ends and does not require specific consensus sequences as in eukaryotes. Two poly(A) polymerases have been identified in Escherichia coli. They are encoded by unlinked genes, neither of which is essential for growth, suggesting significant functional overlap. Polyadenylation promotes the degradation of a regulatory RNA that inhibits the replication of bacterial plasmids and may play a similar role in the degradation of mRNA. However, under certain conditions, poly(A) tracts may lead to mRNA stabilization. Their ability to bind S1 ribosomal protein suggests that poly(A) tracts may also play a role in mRNA translation.
Is polyadenylation a process that stabilizes a protein by adding a string of Adenosine residues to the end of the molecule?
The diversity of polyadenylation sites suggests that mRNA polyadenylation in prokaryotes is a relatively indiscriminate process that can occur at all mRNA's 3'-ends and does not require specific consensus sequences as in eukaryotes.
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, autosomal recessive disorder that results from functional and ultrastructural abnormalities of motile cilia. Patients with PCD have diverse clinical phenotypes that include chronic upper and lower respiratory tract infections, situs inversus, heterotaxy with or without congenital heart disease, and male infertility, among others. In this report, the carrier frequencies for eleven mutations in eight PCD-associated genes (DNAI1, DNAI2, DNAH5, DNAH11, CCDC114, CCDC40, CCDC65, and C21orf59) that had been found in individuals of Ashkenazi Jewish descent were investigated in order to advise on including them in existing clinical mutation panels for this population. Results showed relatively high carrier frequencies for the DNAH5 c.7502G>C mutation (0.58%), the DNAI2 c.1304G>A mutation (0.50%), and the C21orf59 c.735C>G mutation (0.48%), as well as lower frequencies for mutations in DNAI1, CCDC65, CCDC114, and DNAH11 (0.10-0.29%). These results suggest that several of these genes should be considered for inclusion in carrier screening panels in the Ashkenazi Jewish population.
Which is the molecular function of the protein CCDC40?
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, autosomal recessive disorder that results from functional and ultrastructural abnormalities of motile cilia.
Microneedling with dermaroller is a new treatment modality for the treatment of scars, especially acne scars, stretch marks, wrinkles, and for facial rejuvenation. It is a simple and relatively cheap modality that also can be used for transdermal drug delivery.
What are the applications of a Dermaroller ?
Microneedling with dermaroller is a new treatment modality for the treatment of scars, especially acne scars, stretch marks, wrinkles, and for facial rejuvenation. It is a simple and relatively cheap modality that also can be used for transdermal drug delivery.
Deregulation of the cell cycle underlies the aberrant cell proliferation that characterizes cancer and loss of cell cycle checkpoint control promotes genetic instability. During the past two decades, cancer genetics has shown that hyperactivating mutations in growth signalling networks, coupled to loss of function of tumour suppressor proteins, drives oncogenic proliferation. Gene expression profiling of these complex and redundant mitogenic pathways to identify prognostic and predictive signatures and their therapeutic targeting has, however, proved challenging. The cell cycle machinery, which acts as an integration point for information transduced through upstream signalling networks, represents an alternative target for diagnostic and therapeutic interventions. Analysis of the DNA replication initiation machinery and mitotic engine proteins in human tissues is now leading to the identification of novel biomarkers for cancer detection and prognostication, and is providing target validation for cell cycle-directed therapies.
What are negative cell-cycle regulators that can cause cancer when mutated called?
Deregulation of the cell cycle underlies the aberrant cell proliferation that characterizes cancer and loss of cell cycle checkpoint control promotes genetic instability. During the past two decades, cancer genetics has shown that hyperactivating mutations in growth signalling networks, coupled to loss of function of tumour suppressor proteins, drives oncogenic proliferation.
Shapiro syndrome is a rare entity, comprising a triad of recurrent hypothermia, hyperhidrosis and congenital agenesis of the corpus callosum. Fewer than 50 cases have been described, almost invariably in patients presenting in childhood or early adulthood. We present a case of an 80 year old woman presenting with recurrent bouts of shivering, sweating and profound malaise, who sought medical attention because the frequency and severity of attacks worsened in her later years. MRI Brain demonstrated agenesis of the corpus callosum; a rigorous work-up excluded other causes for her symptomatology. The intricate interplay of neuronal networks involved in thermoregulation remains to be fully elucidated and as such, little is known about the pathophysiological mechanisms underlying the clinical manifestations of Shapiro syndrome. We present novel data from FDG-PET imaging of our patient, demonstrating hypermetabolism in a number of brainstem and cerebellar regions during the symptomatic phase. These findings imply that aberrant thermoregulation in Shapiro syndrome involves a number of structures remote from the callosal region. We also present neuropsychometric findings in our patient, of which there have been no reports to date. We postulate that the ageing brain may be more susceptible to the paroxysmal neurochemical fluxes implicated in the syndrome.
List common features of Shapiro syndrome
Shapiro syndrome is a rare entity, comprising a triad of recurrent hypothermia, hyperhidrosis and congenital agenesis of the corpus callosum.
: Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype associated with an increased risk of recurrence and cancer-related death. Unlike hormone receptor-positive or HER2-positive breast cancers, there are limited targeted therapies available to treat TNBC and cytotoxic chemotherapy remains the mainstay of treatment. Sacituzumab govitecan (IMMU-132) is an antibody-drug conjugate targeting Trop-2 expressing cells and selectively delivering SN-38, an active metabolite of irinotecan. : This review covers the mechanism of action, safety and efficacy of sacituzumab govitecan in patients with previously treated, metastatic TNBC. Additionally, efficacy data in other epithelial malignancies is included based on a PubMed search for 'sacituzumab govitecan' and 'clinical trial'. : Sacituzumab govitecan has promising anti-cancer activity in patients with metastatic TNBC previously treated with at least two prior lines of systemic therapy based on a single arm Phase I/II clinical trial. A confirmatory Phase III randomized clinical trial is ongoing. Sacituzumab govitecan has a manageable side effect profile, with the most common adverse events being nausea, neutropenia, and diarrhea. The activity of sacituzumab govitecan likely extends beyond TNBC with promising early efficacy data in many other epithelial cancers, including hormone receptor-positive breast cancer.
Is sacituzumab govitecan effective for breast cancer?
The activity of sacituzumab govitecan likely extends beyond TNBC with promising early efficacy data in many other epithelial cancers, including hormone receptor-positive breast cancer.
Activating mutations in NOTCH1 consitute the most prominent genetic abnormality in T-cell acute lymphoblastic leukemia (T-ALL). However, most T-ALL cell lines with NOTCH1 mutations are resistant to treatment with γ-secretase inhibitors (GSIs). The spotlight is now shifting to the phosphatidylinositide 3-kinase (PI3K)/phosphatase and tensin homolog deleted on chromosome ten (PTEN)/AKT/mammalian target of rapamycin (mTOR) pathway as another key potential target. These two signaling routes are deregulated in many types of cancer. In this review we discuss these two pathways with respect to their signaling mechanisms, functions during T-cell development, and their mutual roles in the development of T-ALL.
Are Notch mutations related to T-cell Acute Lymphoblastic Leukemia (T-ALL)?
Activating mutations in NOTCH1 consitute the most prominent genetic abnormality in T-cell acute lymphoblastic leukemia (T-ALL).
Worldwide over 12 million people were diagnosed with cancer (excluding non-melanoma skin cancer) and 8 million individuals died from cancer in 2008. Recent data indicate that 75-90% of patients with advanced stage diseases or metastatic cancer will experience significant cancer pain. Bone cancer pain is common in patients with advanced breast, prostate, and lung cancer as these tumors have a marked affinity to metastasize to bone. Once tumors metastasize to bone, they are a major cause of morbidity and mortality as the tumor induces significant skeletal remodeling, fractures, pain and anemia; all of which reduce the functional status, quality of life and survival of the patient. Currently, the factors that drive cancer pain are poorly understood, however, several recently introduced models of bone cancer pain that mirror the human condition, are providing insight into the mechanisms that drive bone cancer pain and guiding the development of novel therapies to treat the cancer pain. Several of these therapies have recently been approved by the FDA to treat bone cancer pain (bisphosphonates, denosumab) and others are currently being evaluated in human clinical trials (tanezumab). These new mechanism-based therapies are enlarging the repertoire of modalities available to treat bone cancer pain and improving the quality of life and functional status of patients with bone cancer.
Has Denosumab (Prolia) been approved by FDA?
Several of these therapies have recently been approved by the FDA to treat bone cancer pain (bisphosphonates, denosumab) and others are currently being evaluated in human clinical trials (tanezumab).
Transmembrane beta-barrel (TMB) proteins play pivotal roles in many aspects of bacterial functions. This paper presents a k-nearest neighbor (K-NN) method for discriminating TMB and non-TMB proteins. We start with a method that makes predictions based on a distance computed from residue composition and gradually improve the prediction performance by including homologous sequences and searching for a set of residues and di-peptides for calculating the distance. The final method achieves an accuracy of 97.1%, with 0.876 MCC, 86.4% sensitivity and 98.8% specificity. A web server based on the proposed method is available at http://yanbioinformatics.cs.usu.edu:8080/TMBKNNsubmit.
What are the computational methods for the prediction of beta-barrel transmembrane proteins?
A web server based on the proposed method is available at http://yanbioinformatics.cs.usu.edu:8080/TMBKNNsubmit.
Ferroquine (FQ or SR97193) is a unique ferrocene antimalarial drug candidate which just entered phase IIb clinical trials in autumn 2007. FQ is able to overcome the chloroquine (CQ) resistance problem, an important limit to the control of Plasmodium falciparum, the principal causative agent of malaria. However, as for other therapeutic agents such as chloroquine (CQ) and artemisin, its mechanism of action remains partially unknown. Most investigations have so far focused on comparing the activity of FQ to that of CQ in order to understand how the ferrocene core contributes to a stronger antiplasmodial activity. Studies have already shown that the ferrocene altered the shape, volume, lipophilicity, basicity and also electronic profile of the parent molecule and, hence, its pharmacodynamic behavior. However, few investigations have been undertaken to probe the real contribution of redox properties of the ferrocene (iron(II))/ferricinium (iron(III)) system in FQ as reported in this article. In our experimental and theoretical approach, we considered the redox profile of the ferrocene core of FQ in the specific conditions (acidic and oxidizing) of the parasitic digestive vacuole as a possible discriminating property from CQ in the antimalarial activity.
Which is the causative agent of malaria?
FQ is able to overcome the chloroquine (CQ) resistance problem, an important limit to the control of Plasmodium falciparum, the principal causative agent of malaria.
Glucocorticoids, widely used as immune suppressors, cause osteoporosis by inhibiting bone formation. In MC3T3-E1 osteoblast-like cultures, dexamethasone (DEX) activates glycogen synthase kinase-3beta (GSK3beta) and inhibits a differentiation-related cell cycle that occurs at a commitment stage immediately after confluence. Here we show that DEX inhibition of the differentiation-related cell cycle is associated with a decrease in beta-catenin levels and inhibition of LEF/TCF-mediated transcription. These inhibitory activities are no longer observed in the presence of lithium, a GSK3beta inhibitor. DEX decreased the serum-responsive phosphorylation of protein kinase B/Akt-Ser(473) within minutes, and this inhibition was also observed after 12 h. When the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was inhibited by wortmannin, DEX no longer inhibited beta-catenin levels. Furthermore, DEX-mediated inhibition of LEF/TCF transcriptional activity was attenuated in the presence of dominant negative forms of either PI3K or protein kinase B/Akt. These results suggest cross-talk between the PI3K/Akt and Wnt signaling pathways. Consistent with a role for Wnt signaling in the osteoblast differentiation-related cell cycle, wortmannin partially negated the DEX inhibition of this cell cycle. DEX also induced histone deacetylase (HDAC) 1, which is known to inhibit LEF/TCF transcriptional activity. Overexpression of HDAC1 negated the inhibitory effect of DEX on LEF/TCF transcriptional activity. In the presence of trichostatin A, a deacetylase inhibitor, DEX-mediated inhibition of the differentiation-related cell cycle was partially negated. When administered together, wortmannin and trichostatin A completely negated the inhibitory effect of DEX on the differentiation-related cell cycle. These results suggest that inhibition of a PI3K/Akt/GSK3beta/beta-catenin/LEF axis and stimulation of HDAC1 cooperate to mediate the inhibitory effect of DEX on Wnt signaling and the osteoblast differentiation-related cell cycle.
Is there any cross-talk between the Wnt and the Akt pathways?
DEX decreased the serum-responsive phosphorylation of protein kinase B/Akt-Ser(473) within minutes, and this inhibition was also observed after 12 h. When the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was inhibited by wortmannin, DEX no longer inhibited beta-catenin levels.
Mutations of the huntingtin protein (HTT) gene underlie both adult-onset and juvenile forms of Huntington's disease (HD). HTT modulates mitotic spindle orientation and cell fate in mouse cortical progenitors from the ventricular zone. Using human embryonic stem cells (hESC) characterized as carrying mutations associated with adult-onset disease during pre-implantation genetic diagnosis, we investigated the influence of human HTT and of an adult-onset HD mutation on mitotic spindle orientation in human neural stem cells (NSCs) derived from hESCs. The RNAi-mediated silencing of both HTT alleles in neural stem cells derived from hESCs disrupted spindle orientation and led to the mislocalization of dynein, the p150Glued subunit of dynactin and the large nuclear mitotic apparatus (NuMA) protein. We also investigated the effect of the adult-onset HD mutation on the role of HTT during spindle orientation in NSCs derived from HD-hESCs. By combining SNP-targeting allele-specific silencing and gain-of-function approaches, we showed that a 46-glutamine expansion in human HTT was sufficient for a dominant-negative effect on spindle orientation and changes in the distribution within the spindle pole and the cell cortex of dynein, p150Glued and NuMA in neural cells. Thus, neural derivatives of disease-specific human pluripotent stem cells constitute a relevant biological resource for exploring the impact of adult-onset HD mutations of the HTT gene on the division of neural progenitors, with potential applications in HD drug discovery targeting HTT-dynein-p150Glued complex interactions.
What gene is mutated in Huntington's disease?
Mutations of the huntingtin protein (HTT) gene underlie both adult-onset and juvenile forms of Huntington's disease (HD).
Our results show that MASP-3 is present in relatively high serum concentrations. Moreover, Ficolin-3 is the primary acceptor molecule of MASP-3 among the LCP activator molecules, but MASP-3 appears to down-regulate Ficolin-3 mediated complement activation through the lectin pathway.
Which pathway is activated by ficolin-3?
Moreover, Ficolin-3 is the primary acceptor molecule of MASP-3 among the LCP activator molecules, but MASP-3 appears to down-regulate Ficolin-3 mediated complement activation through the lectin pathway.
People with rare hypertrichosis syndromes became crowd-drawing money-making phenomena in many 19th century sideshow acts. These individuals have been referred to as dog-men, hair-men, and werewolves. In 1993, Baumister et al. described congenital hypertrichosis lanuginose or Ambras syndrome: a distinct form of congenital hypertrichosis characterized by excessive hair growth over the body and face associated with facial and occasional dental anomalies. Much is not known about this syndrome since fewer than 50 cases have been documented worldwide. In this case report, a nine year old girl presented with excessive hair growth throughout her body that was denser along her midline. Furthermore, her face displayed the typical dysmorphic features characteristic of Ambras syndrome: a round tip nose, thickened nasal cartilage, antiverted nares, prominent philtrum with deep groove, and a trapezoid mouth. Oral examination revealed normal oral mucosa with completely missing and unerupted decidious and permanent teeth. Panoramic radiographs confirmed unerupted deciduous teeth. Previous case reports have mentioned the presence of occasional dental anomalies such as retarded first and second dentition and absence of some teeth. However, this is the first reported case of Ambras syndrome presenting with complete anodontia. Prior cytogenetic studies performed on persons with Ambras syndrome have implicated a balanced pericentric inversion of chromosome 8. However, it is likely that dental anomalies are likely a result of a different genetic rearrangement. Further studies are needed to explore the cause of this rare phenotype of Ambras syndrome with complete unerupted dentition.
Describe clinical presentation of Ambras syndrome.
In 1993, Baumister et al. described congenital hypertrichosis lanuginose or Ambras syndrome: a distinct form of congenital hypertrichosis characterized by excessive hair growth over the body and face associated with facial and occasional dental anomalies.
The role of pro-inflammatory cytokines in systemic lupus erythematosus (SLE) remains somewhat controversial. Several studies have shown increased production of TNF alpha and IL-6 in patients with SLE. Increased production of IL-6, TNF alpha, and IL-1 soluble receptors have also been reported. This finding is provocative because the soluble receptors have the capacity to act as antagonists. Several other inflammatory disorders are also associated with increased production of soluble TNF alpha receptors suggesting that this may be a general compensatory mechanism designed to down-regulate inflammation. The recent identification of an SLE disease susceptibility locus near the TNFR2 locus (TNFR p75) suggested the hypothesis that genetically driven differences in soluble TNFR2 production could play a role in the genetic susceptibility to SLE. We therefore characterized the frequency of a genetic polymorphism in the 3' untranslated region of the TNFR2 gene in Caucasoid SLE patients and geographically matched controls. No difference in the gene frequency of the two base-pair polymorphism in SLE patients compared to controls was found, nor was there any association with any particular clinical phenotype.
Which part of the TNFR2 gene is genetically associated with Systemic Lupus Erythematosus?
We therefore characterized the frequency of a genetic polymorphism in the 3' untranslated region of the TNFR2 gene in Caucasoid SLE patients and geographically matched controls.
We have investigated the existence of neural connections between the duodenum and the sphincter of Oddi (SO). Stimulation of duodenal myenteric fiber bundles elicited synaptic responses in SO neurons, which included nicotinic fast excitatory postsynaptic potentials (EPSPs), slow EPSPs, and alpha(2)-adrenoreceptor-mediated inhibitory postsynaptic potentials. After 48 h in organ culture, when extrinsic fibers had diminished, only the fast EPSPs persisted. Duodenal mucosal stimulation also elicited nicotinic fast EPSPs in SO neurons. There was no association between the SO neurons that received duodenal input and their chemical coding. A reciprocal projection also exists from the SO to the duodenum. In acute and cultured preparations, duodenal myenteric stimulation caused antidromic responses in 20% of SO neurons. Furthermore, 45.6 +/- 10.5 neurons in SO ganglia were retrogradely labeled from dye application sites in the duodenum. It is proposed that bidirectional neural communication occurs between the duodenum and the SO and that duodenal neurons provide excitatory fast synaptic input to SO neurons through a reflex that can be activated at the duodenal mucosa.
What 3 organs are the sphincter of Oddi associated with?
We have investigated the existence of neural connections between the duodenum and the sphincter of Oddi (SO). St
Chronic myeloid leukemia cells contain a BCR-ABL oncoprotein with an enhanced tyrosine kinase activity, which is considered to be the principal 'cause' of the leukemia. Though the precise mechanisms underlying the leukemogenesis remains enigmatic, the use of imatinib to inhibit the dysregulated kinase activity has proved remarkably successful in clinical practice. Imatinib was the first small molecule developed to inhibit BCR-ABL tyrosine kinase activity and its success introduced the current era of molecularly targeted therapies for a number of other malignancies. In patients with chronic myeloid leukaemia who develop resistance to imatinib, the Bcr-Abl signaling pathway is often re-established. This has led to the emergence of a number of alternative treatment strategies designed to target the leukemic cell which are resistant to imatinib.
What tyrosine kinase, involved in a Philadelphia- chromosome positive chronic myelogenous leukemia, is the target of Imatinib (Gleevec)?
hronic myeloid leukemia cells contain a BCR-ABL oncoprotein
Mycobacterium abscessus lung disease is difficult to treat due to intrinsic drug resistance and the persistence of drug-tolerant bacteria. Currently, the standard of care is a multidrug regimen with at least 3 active drugs, preferably including a β-lactam (imipenem or cefoxitin). These regimens are lengthy and toxic and have limited efficacy. The search for more efficacious regimens led us to evaluate bedaquiline, a diarylquinoline licensed for treatment of multidrug-resistant tuberculosis. We performed time-kill experiments to evaluate the activity of bedaquiline alone and in combination with the first-line drug imipenem against M. abscessus under various conditions. Against actively growing bacteria, bedaquiline was largely bacteriostatic and antagonized the bactericidal activity of imipenem. Contrarily, against nutrient-starved persisters, bedaquiline was bactericidal, while imipenem was not, and bedaquiline drove the activity of the combination. In an intracellular infection model, bedaquiline and imipenem had additive bactericidal effects. Correlations between ATP levels and the bactericidal activity of imipenem and its antagonism by bedaquiline were observed. Interestingly, the presence of Tween 80 in the media affected the activity of both drugs, enhancing the activity of imipenem and reducing that of bedaquiline. Overall, these results show that bedaquiline and imipenem interact differently depending on culture conditions. Previously reported antagonistic effects of bedaquiline on imipenem were limited to conditions with actively multiplying bacteria and/or the presence of Tween 80, whereas the combination was additive or indifferent against nutrient-starved and intracellular M. abscessus, where promising bactericidal activity of the combination suggests it may have a role in future treatment regimens.
Is Mycobacterium abscessus a human pathogen?
Mycobacterium abscessus lung disease is difficult to treat due to intrinsic drug resistance and the persistence of drug-tolerant bacteria.
Therapeutic apheresis utilizes apheresis procedures in the treatment of a variety of conditions including kidney disease. Therapeutic plasma exchange (TPE) is the most common modality employed with the rationale of rapid reduction of a pathogenic substance distributed primarily in the intravascular compartment; however other techniques which adsorb such pathogenic substances or alter the immune profile have been utilized in diseases affecting native and transplanted kidneys. This article discusses the modalities and technical details of therapeutic apheresis and summarizes its role in individual diseases affecting the kidney. Complications related to pediatric apheresis procedures and specifically related to apheresis in kidney disease are also discussed. Though therapeutic apheresis modalities are employed frequently in children with kidney disease, most experiences are extrapolated from adult studies. International and national registries need to be established to elucidate the role of apheresis modalities in children with kidney disease.
Treatment with plasma exchange (TPE) is used for what diseases
Therapeutic plasma exchange (TPE) is the most common modality employed with the rationale of rapid reduction of a pathogenic substance distributed primarily in the intravascular compartmen
Anaphylaxis is a sudden onset, immediate reaction that implies a risk of death. Think of a "rule of 2s" for anaphylaxis, which implies that reactions usually begin within 2 minutes to 2 hours after injection, infusion, ingestion, contact, or inhalation. Fatalities can be from asphyxiation from laryngeal or oropharyngeal swelling, collapse from hypotensive shock, cardiac arrest, or acute severe bronchoconstriction that causes respiratory failure and arrest. When there is activation of mast cells and basophils in anaphylaxis, chemical mediators are detectable. The preformed mediators from mast cells include histamine, tryptase, carboxypeptidase A, and proteoglycans (heparin, chondroitin sulfates). Newly synthesized mediators include prostaglandin D₂, leukotriene D₄, and platelet activating factor. Crucial actions of the mediators include an abrupt increase in vascular permeability, vascular smooth muscle relaxation, and bronchial smooth muscle contraction. Anaphylaxis can be classified into immunologic, nonimmunologic, or idiopathic based on the associated mechanism. For example, immunologic causes of anaphylaxis are those mediated by immunoglobulin E (IgE) antibodies acting through the FcεR I (foods, insect venom, 32 β-lactam antibiotics), whereas non-IgE immunologic anaphylaxis is mediated without the presence of anti-allergen IgE antibodies or FcεRI activation (radiographic contrast material). Nonimmunologic anaphylaxis involves mast cell mediator release such as occurs with exercise or with cold temperature exposure, or from medications such as opioids or vancomycin. Idiopathic anaphylaxis involves mast cell activation (acutely elevated urine histamine or serum tryptase) and activated lymphocytes. Because anaphylaxis is a medical emergency, the drug of choice is epinephrine, not H antihistamines or H₂ receptor antagonists.
Is anaphylaxis a results of mast cell activation?
When there is activation of mast cells and basophils in anaphylaxis, chemical mediators are detectable.
The field of metabolomics continues to grow rapidly over the last decade and has been proven to be a powerful technology in predicting and explaining complex phenotypes in diverse biological systems. Metabolomics complements other omics, such as transcriptomics and proteomics and since it is a 'downstream' result of gene expression, changes in the metabolome is considered to best reflect the activities of the cell at a functional level. Thus far, metabolomics might be the sole technology capable of detecting complex, biologically essential changes. As one of the omics technology, metabolomics has exciting applications in varied fields, including medical science, synthetic biology, medicine, and predictive modeling of plant, animal and microbial systems. In addition, integrated applications with genomics, transcriptomics, and proteomics provide greater understanding of global system biology. In this review, we discuss recent applications of metabolomics in microbiology, plant, animal, food, and medical science.
List omics technologies comprised in system biology.
In addition, integrated applications with genomics, transcriptomics, and proteomics provide greater understanding of global system biology.
An increased incidence of narcolepsy in children was detected in Scandinavian countries where pandemic H1N1 influenza ASO3-adjuvanted vaccine was used. A campaign of vaccination against pandemic H1N1 influenza was implemented in France using both ASO3-adjuvanted and non-adjuvanted vaccines. As part of a study considering all-type narcolepsy, we investigated the association between H1N1 vaccination and narcolepsy with cataplexy in children and adults compared with matched controls; and compared the phenotype of narcolepsy with cataplexy according to exposure to the H1N1 vaccination. Patients with narcolepsy-cataplexy were included from 14 expert centres in France. Date of diagnosis constituted the index date. Validation of cases was performed by independent experts using the Brighton collaboration criteria. Up to four controls were individually matched to cases according to age, gender and geographic location. A structured telephone interview was performed to collect information on medical history, past infections and vaccinations. Eighty-five cases with narcolepsy-cataplexy were included; 23 being further excluded regarding eligibility criteria. Of the 62 eligible cases, 59 (64% males, 57.6% children) could be matched with 135 control subjects. H1N1 vaccination was associated with narcolepsy-cataplexy with an odds ratio of 6.5 (2.1-19.9) in subjects aged<18 years, and 4.7 (1.6-13.9) in those aged 18 and over. Sensitivity analyses considering date of referral for diagnosis or the date of onset of symptoms as the index date gave similar results, as did analyses focusing only on exposure to ASO3-adjuvanted vaccine. Slight differences were found when comparing cases with narcolepsy-cataplexy exposed to H1N1 vaccination (n=32; mostly AS03-adjuvanted vaccine, n=28) to non-exposed cases (n=30), including shorter delay of diagnosis and a higher number of sleep onset rapid eye movement periods for exposed cases. No difference was found regarding history of infections. In this sub-analysis, H1N1 vaccination was strongly associated with an increased risk of narcolepsy-cataplexy in both children and adults in France. Even if, as in every observational study, the possibility that some biases participated in the association cannot be completely ruled out, the associations appeared robust to sensitivity analyses, and a specific analysis focusing on ASO3-adjuvanted vaccine found similar increase.
What is the reason for the narcolepsy cases developed after H1N1 influenza vaccination?
H1N1 vaccination was strongly associated with an increased risk of narcolepsy-cataplexy in both children and adults in France
Fifty per cent of the genome is discontinuously replicated on the lagging strand as Okazaki fragments. Eukaryotic Okazaki fragments remain poorly characterized and, because nucleosomes are rapidly deposited on nascent DNA, Okazaki fragment processing and nucleosome assembly potentially affect one another. Here we show that ligation-competent Okazaki fragments in Saccharomyces cerevisiae are sized according to the nucleosome repeat. Using deep sequencing, we demonstrate that ligation junctions preferentially occur near nucleosome midpoints rather than in internucleosomal linker regions. Disrupting chromatin assembly or lagging-strand polymerase processivity affects both the size and the distribution of Okazaki fragments, suggesting a role for nascent chromatin, assembled immediately after the passage of the replication fork, in the termination of Okazaki fragment synthesis. Our studies represent the first high-resolution analysis--to our knowledge--of eukaryotic Okazaki fragments in vivo, and reveal the interconnection between lagging-strand synthesis and chromatin assembly.
What cellular process are okazaki fragments associated with?
Fifty per cent of the genome is discontinuously replicated on the lagging strand as Okazaki fragments.
There is increasing evidence that the ABO blood group phenotypes modulates Plasmodium falciparum rosetting and may influence the clinical manifestation of severe malaria. Whether blood group phenotypes are associated with risk of severe falciparum malaria in Odisha, we analyzed 343 adult malaria patients. The results showed high prevalence of blood group B in both mild (n=110) and severe malaria (cerebral malaria [CM]; n=130 and non-cerebral severe malaria [NCSM]; n=103) categories among the non-O group and while type O is significantly associated with protection against CM, patients with type A and B group had increased risk for developing CM. Further, the strength of association for B group (p=< 0.0001) was high and has double the risk of (OR=5.0) of developing CM compared to blood group A (OR=2.5). Such findings may probably be due to strain specific blood group preferences of P. falciparum and high prevalence of B group. However, the ABO blood group distribution of mild malaria was comparable with that of the NCSM group of patients. The lack of association of ABO phenotypes with NCSM is evidence for the hypothesis that the underlying pathogenesis cascades are different in CM and NCSM clinical presentations.
Are people with blood group O protected against severe Malaria?
type O is significantly associated with protection against CM, patients with type A and B group had increased risk for developing CM.
This paper describes a case of transmission of herpetic whitlow to the index finger of a dental student from a patient with herpes simplex virus. The recognition of intraoral viral infections in patients is important because these viruses have serious implications for health care providers. Rubber gloves must be worn when patients with primary or secondary herpetic lesions are treated. Asymptomatic permanent herpes virus carriers must also be treated with appropriate precautions.
Describe Herpetic Whitlow.
This paper describes a case of transmission of herpetic whitlow to the index finger of a dental student from a patient with herpes simplex virus.
Pro-social effects of oxytocin and its homologues are well-documented in birds and mammals. However, in fishes, the effect of isotocin, the homologue of oxytocin, on social behaviour is less clear. Studies in fishes have generally shown no effect of isotocin on social behaviours or even an anti-social effect. In our study, we measured association preference for conspecifics in 92 adult guppies (46 females and 46 males), half of which were injected with isotocin and the other half with an isotocin antagonist. We found that individuals injected with isotocin spent 29% more time associating with conspecifics than individuals injected with an isotocin antagonist. The effect of isotocin on association time did not differ between males and females. Our study provides some of the first evidence of a pro-social effects of isotocin in a fish and suggests that in fishes, isotocin may have a homologous role to oxytocin, at least in promoting shoaling behaviour.
Isotocin is an homolog of what hormone?
isotocin may have a homologous role to oxytocin
Eukaryotic cells have evolved a variety of parallel and redundant DNA damage response pathways that function in a coordinated fashion to prevent the fixation of DNA damage as mutations. Despite the wealth of knowledge on DNA damage signaling on downstream cellular events, the mechanisms of DNA damage recognition, DNA repair as well as DNA damage signaling in the context of chromatin is poorly understood. Chromodomain helicase DNA-binding proteins (CHD) belong to a group of highly conserved chromatin remodeling proteins that are implicated in regulation of transcription. In an effort to understand the physiological role of one of the CHD members in a mammalian model system, we developed a mutant mouse model for the Chd2 gene. The Chd2 mutant mice are highly susceptible to spontaneous lymphoid tumor formation. In this study, we present evidence that the Chd2 mutant cells are defective in their ability to repair DNA damage induced by ionizing and ultraviolet radiation. Consistent with the role of Chd2 in regulating DNA damage responses, the Chd2 mutant cells are also sensitive to DNA damaging agents in clonogenic assays. In summary, our data suggest that the Chd2 protein is involved in regulating the DNA damage responses at the chromatin level.
In which proteins is the chromodomain present?
Chromodomain helicase DNA-binding proteins (CHD) belong to a group of highly conserved chromatin remodeling proteins that are implicated in regulation of transcription. In an effort to understand the physiological role of one of the CHD members in a mammalian model system, we developed a mutant mouse model for the Chd2 gene.
RNA-binding proteins (RBPs) control the fate of nearly every transcript in a cell. However, no existing approach for studying these posttranscriptional gene regulators combines transcriptome-wide throughput and biophysical precision. Here, we describe an assay that accomplishes this. Using commonly available hardware, we built a customizable, open-source platform that leverages the inherent throughput of Illumina technology for direct biophysical measurements. We used the platform to quantitatively measure the binding affinity of the prototypical RBP Vts1 for every transcript in the genome. The scale and precision of these measurements revealed many previously unknown features of this well-studied RBP. Our transcribed genome array (TGA) assayed both rare and abundant transcripts with equivalent proficiency, revealing hundreds of low-abundance targets missed by previous approaches. These targets regulated diverse biological processes including nutrient sensing and the DNA damage response, and implicated Vts1 in de novo gene "birth." TGA provided single-nucleotide resolution for each binding site and delineated a highly specific sequence and structure motif for Vts1 binding. Changes in transcript levels in Δ cells established the regulatory function of these binding sites. The impact of Vts1 on transcript abundance was largely independent of where it bound within an mRNA, challenging prevailing assumptions about how this RBP drives RNA degradation. TGA thus enables a quantitative description of the relationship between variant RNA structures, affinity, and in vivo phenotype on a transcriptome-wide scale. We anticipate that TGA will provide similarly comprehensive and quantitative insights into the function of virtually any RBP.
Which was the first species in which a de novo gene emergence ("gene birth") was reported?
These targets regulated diverse biological processes including nutrient sensing and the DNA damage response, and implicated Vts1 in de novo gene "birth."
Genome editing has attracted wide interest for the generation of cellular models of disease using human pluripotent stem cells and other cell types. CRISPR-Cas systems and TALENs can target desired genomic sites with high efficiency in human cells, but recent publications have led to concern about the extent to which these tools may cause off-target mutagenic effects that could potentially confound disease-modeling studies. Using CRISPR-Cas9 and TALEN targeted human pluripotent stem cell clones, we performed whole-genome sequencing at high coverage in order to assess the degree of mutagenesis across the entire genome. In both types of clones, we found that off-target mutations attributable to the nucleases were very rare. From this analysis, we suggest that, although some cell types may be at risk for off-target mutations, the incidence of such effects in human pluripotent stem cells may be sufficiently low and thus not a significant concern for disease modeling and other applications.
Is TALEN being used on stem cells?
Using CRISPR-Cas9 and TALEN targeted human pluripotent stem cell clones, we performed whole-genome sequencing at high coverage in order to assess the degree of mutagenesis across the entire genome.
Mast cells are important elements of the body response to foreign antigens, being those represented either by small molecules (allergic response) or harbored by foreign microorganisms (response to parasite infection). These cells derive from hematopoietic stem/progenitor cells present in the marrow. However, in contrast with most of the other hematopoietic lineages, mast cells do not differentiate in the marrow but in highly vascularized extramedullary sites, such as the skin or the gut. Mast cell differentiation in the marrow is activated as part of the body response to parasites. We will review here the mast cell differentiation pathway and what is known of its major intrinsic and extrinsic control mechanisms. It will also be described that thrombopoietin, the ligand for the Mpl receptor, in addition to its pivotal rule in the control of thrombocytopoiesis and of hematopoietic stem/progenitor cell proliferation, exerts a regulatory function in mast cell differentiation. Some of the possible implications of this newly described biological activity of thrombopoietin will be discussed.
What biologic process in the body is associated with Mast cells?
Mast cells are important elements of the body response to foreign antigens, being those represented either by small molecules (allergic response) or harbored by foreign microorganisms (response to parasite infection).
Maladaptive cardiac hypertrophy results in phenotypic changes in several genes that are thyroid hormone responsive, suggesting that thyroid hormone receptor (TR) function may be altered by cellular kinases, including protein kinase C (PKC) isozymes that are activated in pathological hypertrophy. To investigate the role of PKC signaling in regulating TR function, cultured neonatal rat ventricular myocytes were transduced with adenovirus (Ad) expressing wild-type (wt) or kinase-inactive (dn) PKC alpha or constitutively active (ca) PKC delta and PKC epsilon. Overexpression of wtPKC alpha, but not caPKC delta or caPKC epsilon, induced a 28-fold increase (P < 0.001) in TR alpha1 protein in the nuclear compartment and a smaller increase in the cytosol. Furthermore, TR alpha1 mRNA was increased 55-fold (P < 0.001). This effect of PKC alpha was dependent on its kinase activity because dnPKC alpha was without effect. Phorbol 12-myristate 13-acetate (PMA) induced nuclear translocation of endogenous PKC alpha and Ad-wtPKC alpha concomitantly with an increase in nuclear TR alpha1 protein. In contrast, PMA-induced nuclear translocation of dnPKC alpha resulted in a decrease of TR alpha1. The increase in TR alpha1 protein in Ad-wtPKC alpha-transduced cardiomyocytes was not the result of a reduced rate of protein degradation, nor was the half-life of TR alpha1 mRNA prolonged, suggesting a PKC alpha-mediated effect on TR alpha transcription. Although phosphorylation of ERK1/2 was increased in Ad-wtPKC alpha-transduced cells, inhibition of phospho-ERK did not change TR alpha1 expression. PKC alpha overexpression in cardiomyocytes caused marked repression of triiodothyronine (T3)-responsive genes, alpha-myosin heavy chain, and the sarcoplasmic reticulum calcium-activated adenosinetriphosphatase SERCA2. Treatment with T3 for 4 h resulted in significant reductions of PKC alpha in nuclear and cytosolic compartments, and decreased TR alpha1 mRNA and protein, with normalization of phenotype. These results implicate PKC alpha as a regulator of TR function and suggest that nuclear localization of PKC alpha may control transcription of the TR alpha gene, and consequently, affect cardiac phenotype.
Which genes does thyroid hormone receptor alpha1 regulate in the heart?
PKC alpha overexpression in cardiomyocytes caused marked repression of triiodothyronine (T3)-responsive genes, alpha-myosin heavy chain, and the sarcoplasmic reticulum calcium-activated adenosinetriphosphatase SERCA2. Treatment with T3 for 4 h resulted in significant reductions of PKC alpha in nuclear and cytosolic compartments, and decreased TR alpha1 mRNA and protein, with normalization of phenotype.
The HU protein is a small, basic, heat-stable DNA-binding protein that is well-conserved in prokaryotes and is associated with the bacterial nucleoid. In enterobacteria, including Escherichia coli, HU is a heterotypic dimer, HUalphabeta, composed of two closely related sub-units encoded by the hupA and hupB genes, respectively. HU was shown to participate in vitro in the initiation of DNA replication as an accessory factor to assist the action of DnaA protein in the unwinding of oriC DNA. To further elucidate the role of HU in the regulation of the DNA replication initiation process, we tested the synchrony phenotype in the absence of either one or both HU sub-units. The hupAB mutant exhibits an asynchronous initiation, the hupA mutant shows a similar reduced synchrony, whereas the hupB mutant shows a normal phenotype. Using a thermosensitive dnaA46 strain (dnaA46ts), an initiation mutant, we reveal a special role of HUbeta. The presence of a plasmid overproducing HUbeta in a dnaA46ts lacking HU (hupAB background) compensates for the thermosensitivity of this initiation mutant. Moreover, the overproduction of HUbeta confers to dnaA46ts a pattern of asynchrony similar to that of a dnaAcos, the intragenic suppressor of dnaA46ts. We show that the relative ratio of HUalpha versus HUbeta is greatly perturbed in dnaA46ts which accumulates little, if any, HUbeta. Therefore, the suppression of thermosensitivity in dnaA46hupAB by HUbeta may be caused by an unexpected absence of HUbeta in the dnaA46ts mutant. Visibly the HU composition is sensitive to the different states of DnaA, and may play a role during the regulation of the initiation process of the DNA replication by affecting subsequent events along the cell cycle.
Which proteins act as histone-like molecules in prokaryotes?
HU protein is a small, basic, heat-stable DNA-binding protein that is well-conserved in prokaryotes and is associated with the bacterial nucleoid
Thyroid hormone transport into cells requires plasma membrane transport proteins. Mutations in one of these, monocarboxylate transporter 8 (MCT8), have been identified as underlying cause for the Allan-Herndon-Dudley syndrome, an X-linked mental retardation in which the patients also present with abnormally high 3',3,5-triiodothyronine (T(3)) plasma levels. Mice deficient in Mct8 replicate the thyroid hormone abnormalities observed in the human condition. However, no neurological deficits have been described in mice lacking Mct8. Therefore, we subjected Mct8-deficient mice to a comprehensive immunohistochemical, neurological, and behavioral screen. Several behavioral abnormalities were found in the mutants. Interestingly, some of these behavioral changes are compatible with hypothyroidism, whereas others rather indicate hyperthyroidism. We thus hypothesized that neurons exclusively dependent on Mct8 are in a hypothyroid state, whereas neurons expressing other T(3) transporters become hyperthyroid, if they are exposed directly to the high plasma T(3). The majority of T(3) uptake in primary cortical neurons is mediated by Mct8, but pharmacological inhibition suggested functional expression of additional T(3) transporter classes. mRNAs encoding six T(3) transporters, including L-type amino acid transporters (LATs), were coexpressed with Mct8 in isolated neurons. We then demonstrated Lat2 expression in cultured neurons and throughout murine brain development. In contrast, LAT2 is expressed in microglia in the developing human brain during gestation, but not in neurons. We suggest that lack of functional complementation by alternative thyroid hormone transporters in developing human neurons precipitates the devastating neurodevelopmental phenotype in MCT8-deficient patients, whereas Mct8-deficient mouse neurons are functionally complemented by other transporters, for possibly Lat2.
Which hormone concentrations are altered in patients with the Allan–Herndon–Dudley syndrome?
Mutations in one of these, monocarboxylate transporter 8 (MCT8), have been identified as underlying cause for the Allan-Herndon-Dudley syndrome, an X-linked mental retardation in which the patients also present with abnormally high 3',3,5-triiodothyronine (T(3)) plasma levels.
Feline Infectious Peritonitis (FIP) is a severe fatal immune-augmented disease in cat population. It is caused by FIP virus (FIPV), a virulent mutant strain of Feline Enteric Coronavirus (FECV). Current treatments and prophylactics are not effective. The in vitro antiviral properties of five circular Triple-Helix Forming Oligonucleotide (TFO) RNAs (TFO1 to TFO5), which target the different regions of virulent feline coronavirus (FCoV) strain FIPV WSU 79-1146 genome, were tested in FIPV-infected Crandell-Rees Feline Kidney (CRFK) cells. RT-qPCR results showed that the circular TFO RNAs, except TFO2, inhibit FIPV replication, where the viral genome copy numbers decreased significantly by 5-fold log10 from 10(14) in the virus-inoculated cells to 10(9) in the circular TFO RNAs-transfected cells. Furthermore, the binding of the circular TFO RNA with the targeted viral genome segment was also confirmed using electrophoretic mobility shift assay. The strength of binding kinetics between the TFO RNAs and their target regions was demonstrated by NanoITC assay. In conclusion, the circular TFOs have the potential to be further developed as antiviral agents against FIPV infection.
Is the FIP virus thought to be a mutated strain for the Feline enteric Coronavirus?
It is caused by FIP virus (FIPV), a virulent mutant strain of Feline Enteric Coronavirus (FECV).
Neuromedin U (NmU), originally isolated from porcine spinal cord and later from other species, is a novel peptide that potently contracts smooth muscle. NmU interacts with two G protein-coupled receptors designated as NmU-1R and NmU-2R. This study demonstrates a potential proinflammatory role for NmU. In a mouse Th2 cell line (D10.G4.1), a single class of high affinity saturable binding sites for (125)I-labeled NmU (K(D) 364 pM and B(max) 1114 fmol/mg protein) was identified, and mRNA encoding NmU-1R, but not NmU-2R, was present. Competition binding analysis revealed equipotent, high affinity binding of NmU isopeptides to membranes prepared from D10.G4.1 cells. Exposure of these cells to NmU isopeptides resulted in an increase in intracellular Ca(2+) concentration (EC(50) 4.8 nM for human NmU). In addition, NmU also significantly increased the synthesis and release of cytokines including IL-4, IL-5, IL-6, IL-10, and IL-13. Studies using pharmacological inhibitors indicated that maximal NmU-evoked cytokine release required functional phospholipase C, calcineurin, MEK, and PI3K pathways. These data suggest a role for NmU in inflammation by stimulating cytokine production by T cells.
What is Neuromedin U (NmU)
Neuromedin U (NmU), originally isolated from porcine spinal cord and later from other species, is a novel peptide that potently contracts smooth muscle.
Optogenetics has revolutionized the capability of controlling genetically modified neurons in vitro and in vivo and has become an indispensable neuroscience tool. Using light as a probe for selective neuronal activation or inhibition and as a means to read out neural activity has dramatically enhanced our understanding of complex neural circuits. However, a common limitation of optogenetic studies to date is their invasiveness and spatiotemporal range. Direct viral injections into the brain tissue along with implantation of optical fibers and recording electrodes can disrupt the neuronal circuitry and cause significant damage. Conventional approaches are spatially limited around the site of the direct injection and insufficient in examining large networks throughout the brain. Lastly, optogenetics is currently not easily scalable to large animals or humans. Here, we demonstrate that optogenetic excitation can be achieved entirely non-invasively through the intact skull in mice. Using a needle-free combination of focused ultrasound-mediated viral delivery and extracorporeal illumination with red light, we achieved selective neuronal activation at depths up to 4 mm in the murine brain, confirmed through cFos expression and electrophysiology measurements within the treated areas. Ultrasound treatment significantly reduced freezing time during recall in fear conditioning experiments, but remote light exposure had a moderate effect on the freezing behavior of mice treated with viral vectors. The proposed method has the potential to open new avenues of studying, but also stimulating, neuronal networks, in an effort to elucidate normal or dysfunctional brain activity and treat neurological diseases. Finally, the same non-invasive methodology could be combined with gene therapy and applied to other organs, such as the eye and the heart.
Optogenetics refers to the study of gene expression optimization
Optogenetics has revolutionized the capability of controlling genetically modified neurons in vitro and in vivo and has become an indispensable neuroscience tool. Using light as a probe for selective neuronal activation or inhibition and as a means to read out neural activity has dramatically enhanced our understanding of complex neural circuits.
Heterotachy is a general term to describe positions that evolve at different rates in different lineages. Heterotachy also can generally be viewed as multivariate rates-across-sites variation, which can be described as randomly drawing rates (or branch lengths) from a multivariate distribution for each branch at each site (Wu J, Susko E. 2009. General heterotachy and distance method adjustments. Mol Biol Evol. 26:2689-2697). Motivated by this result, we propose three new distance-based tests: a heterogeneity test, a heterotachy test, and a within-gene heterotachy test and demonstrate with simulations that they perform well under a wide range of conditions. We also applied the first two tests to two real data sets and found that although all these data sets showed significant evidence of heterotachy, there were subtrees for which the data were consistent with an equal rates or rates-across-sites model.heterogeneity, heterotachy, within-gene heterotachy, covarion model, distance method, hypothesis test.
What heterotachy states about molecular evolutionary processes?
Heterotachy is a general term to describe positions that evolve at different rates in different lineages.
Telomerase reverse transcriptase (TERT) is up-regulated in a variety of human neoplasms. Mutations in the core promoter region of the TERT gene, which increases promoter activity, have been reported in melanomas and a variety of human neoplasms, including gliomas. In the present study, we screened for TERT promoter mutations by direct DNA sequencing in a population-based collection of 358 glioblastomas. TERT promoter mutations (C228T, C250T) were detected in 55 % glioblastomas analysed. Of these, 73 % had a C228T mutation, and 27 % had a C250T mutation; only one glioblastoma had both C228T and C250T mutations. TERT promoter mutations were significantly more frequent in primary (IDH1 wild-type) glioblastomas (187/322; 58 %) than in secondary (IDH1 mutated) glioblastomas (10/36, 28 %; P = 0.0056). They showed significant inverse correlations with IDH1 mutations (P = 0.0056) and TP53 mutations (P = 0.043), and a significant positive correlation with EGFR amplification (P = 0.048). Glioblastoma patients with TERT mutations showed a shorter survival than those without TERT mutations in univariate analysis (median, 9.3 vs. 10.5 months; P = 0.015) and multivariate analysis after adjusting for age and gender (HR 1.38, 95 % CI 1.01-1.88, P = 0.041). However, TERT mutations had no significant impact on patients' survival in multivariate analysis after further adjusting for other genetic alterations, or when primary and secondary glioblastomas were separately analysed. These results suggest that the prognostic value of TERT mutations for poor survival is largely due to their inverse correlation with IDH1 mutations, which are a significant prognostic marker of better survival in patients with secondary glioblastomas.
Is there an association between TERT promoter mutation and survival of glioblastoma patients?
Glioblastoma patients with TERT mutations showed a shorter survival than those without TERT mutations in univariate analysis (median, 9.3 vs. 10.5 months; P = 0.015) and multivariate analysis after adjusting for age and gender (HR 1.38, 95 % CI 1.01-1.88, P = 0.041). However, TERT mutations had no significant impact on patients' survival in multivariate analysis after further adjusting for other genetic alterations, or when primary and secondary glioblastomas were separately analysed. These results suggest that the prognostic value of TERT mutations for poor survival is largely due to their inverse correlation with IDH1 mutations, which are a significant prognostic marker of better survival in patients with secondary glioblastomas.
A survey of reptile-associated ticks and their infection status with severe fever with thrombocytopenia syndrome (SFTS) virus was conducted to determine the relative abundance and distribution among lizards, skinks, and snakes in the Republic of Korea (ROK). In total, 132 reptiles, including 49 lizards (two species), 15 skinks (one species), and 68 snakes (eight species) were collected. In total, 84 ixodid ticks belonging to two genera (Ixodes and Amblyomma) were collected from 28/132 (21.2%) lizards, skinks, and snakes. Ixodes nipponensis Kitaoka & Saito was only collected from lizards and skinks, while Amblyomma testudinarium Koch was only collected from snakes. Takydromus wolteri had the highest tick index (0.7; total number ticks/total number collected hosts) among lizards and skinks, while Rhabdophis tigrinus had the highest tick index (2.2) among the snakes. Ixodes nipponensis larvae and nymphs accounted for 11.1% and 88.9%, respectively, of all ticks collected from lizards and skinks, while only A. testudinarium nymphs were collected from snakes. Nymphs of both species of ticks were collected from lizards and skinks from April to October, while I. nipponensis larvae were collected only from September to October. Ixodes nipponensis larvae and nymphs were preferentially attached to the lateral trunk (83.3%) and the foreleg axillae (16.7%) of lizards and skinks. SFTS virus was detected in both I. nipponensis and A. testudinarium collected from lizards and snakes. Phylogenetic analysis of SFTS viruses of ticks collected from two lizards and one snake demonstrated close relationships with SFTS virus strains observed from humans and ticks in the ROK, China, and Japan. These results implicate lizards and snakes as potential hosts of SFTS virus.
Which species is the carrier of the SFTS ( severe fever with thrombocytopenia syndrome) virus?
In total, 84 ixodid ticks belonging to two genera (Ixodes and Amblyomma) were collected from 28/132 (21.2%) lizards, skinks, and snakes.
The aim of this Phase 1/2, 2-part, multicenter trial was to report clinical safety and efficacy of long-term golodirsen treatment among ambulatory patients with exon 53 skip-amenable Duchenne muscular dystrophy (DMD). Part 1 was a 12-week, randomized, double-blind, placebo-controlled, dose-titration study followed by 9-week safety review. Part 2 was a 168-week, open-label evaluation of golodirsen 30 mg/kg. Part 1 primary endpoint was safety. Part 2 primary endpoints were dystrophin protein expression and 6-minute walk test (6MWT); secondary endpoints were percent predicted forced vital capacity (FVC%p) and safety. ambulation analyses used mutation-matched external natural history controls. All patients from Part 1 (golodirsen,  = 8; placebo,  = 4) plus 13 additional patients entered Part 2; 23 completed the study. Adverse events were generally mild, nonserious, and unrelated to golodirsen, with no safety-related discontinuations or deaths. Golodirsen increased dystrophin protein (16.0-fold;  < 0.001) and exon skipping (28.9-fold;  < 0.001). At 3 years, 6MWT change from baseline was -99.0 m for golodirsen-treated patients versus -181.4 m for external controls ( = 0.067), and loss of ambulation occurred in 9% versus 26% ( = 0.21). FVC%p declined 8.4% over 3 years in golodirsen-treated patients, comparing favorably with literature-reported rates. This study provides evidence for golodirsen biologic activity and long-term safety in a declining DMD population and suggests functional benefit versus external controls. Clinical Trial Registration number: NCT02310906.
Is golodirsen effective for the treatment of Duchenne muscular dystrophy?
This study provides evidence for golodirsen biologic activity and long-term safety in a declining DMD population and suggests functional benefit versus external controls.
DNA polymerase θ (Pol θ) is implicated in various cellular processes including double-strand break repair and apurinic/apyrimidinic site bypass. Because Pol θ expression correlates with poor cancer prognosis, the ability of Pol θ to bypass the C4'-oxidized abasic site (C4-AP) and 2-deoxyribonolactone (L), which are generated by cytotoxic agents, is of interest. Translesion synthesis and subsequent extension by Pol θ past C4-AP or L and an abasic site (AP) or its tetrahydrofuran analogue (F) was examined. Pol θ conducts translesion synthesis on templates containing AP and F with similar efficiencies and follows the "A-rule," inserting nucleotides in the order A > G > T. Translesion synthesis on templates containing C4-AP and L is less efficient than AP and F, and the preference for A insertion is reduced for L and absent for C4-AP. Extension past all abasic lesions (AP, F, C4-AP, and L) was significantly less efficient than translesion synthesis and yielded deletions caused by the base one or two nucleotides downstream from the lesion being used as a template, with the latter being favored. These results suggest that bypass of abasic lesions by Pol θ is highly mutagenic.
Is DNA polymerase θ involved in DNA repair?
DNA polymerase θ (Pol θ) is implicated in various cellular processes including double-strand break repair and apurinic/apyrimidinic site bypass.
BAFF, a member of the TNF superfamily, has been recognized as a good target for autoimmune diseases. Belimumab, an anti-BAFF monoclonal antibody, was approved by the FDA for use in treating systemic lupus erythematosus. However, the molecular basis of BAFF neutralization by belimumab remains unclear. Here our crystal structure of the BAFF-belimumab Fab complex shows the precise epitope and the BAFF-neutralizing mechanism of belimumab, and demonstrates that the therapeutic activity of belimumab involves not only antagonizing the BAFF-receptor interaction, but also disrupting the formation of the more active BAFF 60-mer to favor the induction of the less active BAFF trimer through interaction with the flap region of BAFF. In addition, the belimumab HCDR3 loop mimics the DxL(V/L) motif of BAFF receptors, thereby binding to BAFF in a similar manner as endogenous BAFF receptors. Our data thus provides insights for the design of new drugs targeting BAFF for the treatment of autoimmune diseases.
Which is the target of belimumab in Systemic Lupus Erythematosus treatment?
Belimumab, an anti-BAFF monoclonal antibody
Alterations in the regulation of gene expression are frequently associated with developmental diseases or cancer. Transcription activation is a key phenomenon in the regulation of gene expression. In all eukaryotes, mediator of RNA polymerase II transcription (Mediator), a large complex with modular organization, is generally required for transcription by RNA polymerase II, and it regulates various steps of this process. The main function of Mediator is to transduce signals from the transcription activators bound to enhancer regions to the transcription machinery, which is assembled at promoters as the preinitiation complex (PIC) to control transcription initiation. Recent functional studies of Mediator with the use of structural biology approaches and functional genomics have revealed new insights into Mediator activity and its regulation during transcription initiation, including how Mediator is recruited to transcription regulatory regions and how it interacts and cooperates with PIC components to assist in PIC assembly. Novel roles of Mediator in the control of gene expression have also been revealed by showing its connection to the nuclear pore and linking Mediator to the regulation of gene positioning in the nuclear space. Clear links between Mediator subunits and disease have also encouraged studies to explore targeting of this complex as a potential therapeutic approach in cancer and fungal infections.
What is the role of the Mediator in gene expression?
Transcription activation is a key phenomenon in the regulation of gene expression. In all eukaryotes, mediator of RNA polymerase II transcription (Mediator), a large complex with modular organization, is generally required for transcription by RNA polymerase II, and it regulates various steps of this process. The main function of Mediator is to transduce signals from the transcription activators bound to enhancer regions to the transcription machinery, which is assembled at promoters as the preinitiation complex (PIC) to control transcription initiation.
A cytosine DNA methyltransferase containing a chromodomain, Zea methyltransferase2 (Zmet2), was cloned from maize. The sequence of ZMET2 is similar to that of the Arabidopsis chromomethylases CMT1 and CMT3, with C-terminal motifs characteristic of eukaryotic and prokaryotic DNA methyltransferases. We used a reverse genetics approach to determine the function of the Zmet2 gene. Plants homozygous for a Mutator transposable element insertion into motif IX had a 13% reduction in methylated cytosines. DNA gel blot analysis of these plants with methylation-sensitive restriction enzymes and bisulfite sequencing of a 180-bp knob sequence showed reduced methylation only at CpNpG sites. No reductions in methylation were observed at CpG or asymmetric sites in heterozygous or homozygous mutant plants. Our research shows that chromomethylase Zmet2 is required for in vivo methylation of CpNpG sequences.
What is the role of chromomethylases in plants?
The sequence of ZMET2 is similar to that of the Arabidopsis chromomethylases CMT1 and CMT3, with C-terminal motifs characteristic of eukaryotic and prokaryotic DNA methyltransferases.
The chromodomain of the HP1 family of proteins recognizes histone tails with specifically methylated lysines. Here, we present structural, energetic, and mutational analyses of the complex between the Drosophila HP1 chromodomain and the histone H3 tail with a methyllysine at residue 9, a modification associated with epigenetic silencing. The histone tail inserts as a beta strand, completing the beta-sandwich architecture of the chromodomain. The methylammonium group is caged by three aromatic side chains, whereas adjacent residues form discerning contacts with one face of the chromodomain. Comparison of dimethyl- and trimethyllysine-containing complexes suggests a role for cation-pi and van der Waals interactions, with trimethylation slightly improving the binding affinity.
Which histone mark is recognized by HP1?
Here, we present structural, energetic, and mutational analyses of the complex between the Drosophila HP1 chromodomain and the histone H3 tail with a methyllysine at residue 9, a modification associated with epigenetic silencing
One of the challenges in the analysis of gene expression data is placing the results in the context of other data available about genes and their relationships to each other. Here, we approach this problem in the study of gene expression changes associated with age in two areas of the human prefrontal cortex, comparing two computational methods. The first method, "overrepresentation analysis" (ORA), is based on statistically evaluating the fraction of genes in a particular gene ontology class found among the set of genes showing age-related changes in expression. The second method, "functional class scoring" (FCS), examines the statistical distribution of individual gene scores among all genes in the gene ontology class and does not involve an initial gene selection step. We find that FCS yields more consistent results than ORA, and the results of ORA depended strongly on the gene selection threshold. Our findings highlight the utility of functional class scoring for the analysis of complex expression data sets and emphasize the advantage of considering all available genomic information rather than sets of genes that pass a predetermined "threshold of significance."
What is the basis of the methodology of "functional class scoring" (FCS) for the analysis of gene expression data?
The second method, "functional class scoring" (FCS), examines the statistical distribution of individual gene scores among all genes in the gene ontology class and does not involve an initial gene selection step.
Occludin is a transmembrane tight junction (TJ) protein that plays an important role in TJ assembly and regulation of the epithelial barrier function, but the mechanisms underlying its post-transcriptional regulation are unknown. The RNA-binding protein HuR modulates the stability and translation of many target mRNAs. Here, we investigated the role of HuR in the regulation of occludin expression and therefore in the intestinal epithelial barrier function. HuR bound the 3'-untranslated region of the occludin mRNA and enhanced occludin translation. HuR association with the occludin mRNA depended on Chk2-dependent HuR phosphorylation. Reduced HuR phosphorylation by Chk2 silencing or by reduction of Chk2 through polyamine depletion decreased HuR-binding to the occludin mRNA and repressed occludin translation, whereas Chk2 overexpression enhanced (HuR/occludin mRNA) association and stimulated occludin expression. In mice exposed to septic stress induced by cecal ligation and puncture, Chk2 levels in the intestinal mucosa decreased, associated with an inhibition of occludin expression and gut barrier dysfunction. These results indicate that HuR regulates occludin mRNA translation through Chk2-dependent HuR phosphorylation and that this influence is crucial for maintenance of the epithelial barrier integrity in the intestinal tract.
Which are the main functions of the human HuR (ELAVL1) protein in fibroblasts?
The RNA-binding protein HuR modulates the stability and translation of many target mRNAs.
TFIIS is a transcription elongation factor that stimulates transcript cleavage activity of arrested RNA polymerase II (Pol II). Recent studies revealed that TFIIS has also a role in Pol II transcription initiation. To improve our understanding of TFIIS function in vivo, we performed genome-wide location analysis of this factor. Under normal growth conditions, TFIIS was detected on Pol II-transcribed genes, and TFIIS occupancy was well correlated with that of Pol II, indicating that TFIIS recruitment is not restricted to NTP-depleted cells. Unexpectedly, TFIIS was also detected on almost all Pol III-transcribed genes. TFIIS and Pol III occupancies correlated well genome-wide on this novel class of targets. In vivo, some dst1 mutants were partly defective in tRNA synthesis and showed a reduced Pol III occupancy at the restrictive temperature. In vitro transcription assays suggested that TFIIS may affect Pol III start site selection. These data provide strong in vivo and in vitro evidence in favor of a role of TFIIS as a general Pol III transcription factor.
What is the function of the TFIIS transcriptional factor (Dst1) in yeast?
TFIIS and Pol III occupancies correlated well genome-wide on this novel class of targets.
This review mainly focuses on the structure, function of the sarco(endo)plasmic reticulum calcium pump (SERCA) and its role in genesis of arrhythmias. SERCA is a membrane protein that belongs to the family of P-type ion translocating ATPases and pumps free cytosolic calcium into intracellular stores. Active transport of Ca2+ is achieved, according to the E1-E2 model, changing of SERCA structure by Ca2+. The affinity of Ca2+ -binding sites varies from high (E1) to low (E2). Three different SERCA genes were identified-SERCA1, SERCA2, and SERCA3. SERCA is mainly represented by the SERCA2a isoform in the heart. In heart muscle, during systole, depolarization triggers the release of Ca2+ from the sarcoplasmic reticulum (SR) and starts contraction. During diastole, muscle relaxation occurs as Ca2+ is again removed from cytosol, predominantly by accumulation into SR via the action of SERCA2a. The main regulator of SERCA2a is phospholamban and another regulator proteolipid of SERCA is sarcolipin. There are a lot of studies on the effect of decreased and/or increased SERCA activity in genesis of arrhythmia. Actually both decrease and increase of SERCA activity in the heart result in some pathological mechanisms such as heart failure and arrhythmia.
Which is the main calcium pump of the sarcoplasmic reticulum?
Three different SERCA genes were identified-SERCA1, SERCA2, and SERCA3. SERCA is mainly represented by the SERCA2a isoform in the heart.
Using a novel thiol affinity chromatography approach to purify macroH2A1-containing chromatin fragments, we examined the distribution of macroH2A1 histone variants in mouse liver chromatin. We found that macroH2A1 was depleted on the transcribed regions of active genes. This depletion was observed on all of the 20 active genes that we probed, with only one site showing a small amount of enrichment. In contrast, macroH2A1 was concentrated on the inactive X chromosome, consistent with our previous immunofluorescence studies. This preferential localization was seen on genes that are active in liver, genes that are inactive in liver, and intergenic regions but was absent from four regions that escape X inactivation. These results support the hypothesis that macroH2As function as transcriptional repressors. Also consistent with this hypothesis is our finding that the heterochromatin protein HP1beta copurifies with the macroH2A1-containing chromatin fragments. This study presents the first detailed examination of the distribution of macroH2A1 variants on specific sequences. Our results indicate that macroH2As have complex distribution patterns that are influenced by both local factors and long-range mechanisms.
In which genomic positions is the histone variant macroH2A enriched?
We found that macroH2A1 was depleted on the transcribed regions of active genes
Wilson's disease is an inherited disorder leading to accumulation of copper in tissues, mainly in the liver and brain. Genetic defect is in the gene coding ATPase type P (ATP7B). The inheritance is autosomal recessive. Up to now, more then 500 mutations causing Wilson's disease were described. The most frequent mutation in Central Europe is mutation H1069Q. The manifestation of Wilson's disease is usually hepatic or neurologic. Hepatic form is manifested by acute or chronic hepatitis, steatosis or cirrhosis. Neurologic involvement is manifested usually after 20 year of age by motor disturbances (tremor, disturbed speech, problems with writing), which could progress into severe extrapyramidal syndrome with tremor, rigidity, dysartria, dysfagia and muscle contracture. Diagnosis is based on clinical and laboratory examinations (neurologic symptoms, liver disease, low serum ceruloplasmin levels, elevated free copper concentration in serum, high urine copper excretion, and presence of Kayser-Fleischer rings). Confirmation of diagnosis is done by hepatic copper concentration in liver biopsy or by genetic examination. Untreated disease leads to the death of a patient. Treatment is based on chelating agents decreasing the copper content by excretion into urine (D-penicillamine, trientine) or on agents preventing absorption of copper from food (zinc, ammonium-tetrahiomolybdene). Patients with asymptomatic Wilson's disease have to be treated as well. In Czech Republic either penicillamine or zinc are used. Liver transplantation is indicated in patients with fulminant liver failure or decompensated cirrhosis. Screening in families of affected patients (all siblings) is obvious.
What is the mode of inheritance of Wilson's disease?
The inheritance is autosomal recessive.
RNA aptamers were selected against an affinity column containing a farnesylated peptide modeled after the carboxyl terminus of K ras, the major oncogenic form of this small G protein family. After 10-rounds of selection, 25% of the RNA applied to the column could be specifically eluted. Sequence analysis of the binding RNA aptamers revealed two consensus sequences--GGGUGGG and GGGAGG. Quantitative fluorescence binding studies on two of the high-affinity aptamers, showed a binding affinities of 139 nM and 0.93 microM, respectively for the farnesylated peptide. Binding to the nonfarnesylated peptide was at least 10-fold weaker, showing that the aptamers can recognize the hydrophobic farnesyl moiety. High affinity aptamers could be useful in specifically interfering with oncogenic ras function in particular, and G proteins in general.
What is the role of peptide aptamers?
Binding to the nonfarnesylated peptide was at least 10-fold weaker, showing that the aptamers can recognize the hydrophobic farnesyl moiety.
To maintain genomic integrity, DNA repair enzymes continually remove damaged bases and lesions resulting from endogenous and exogenous processes. These repair enzymes must distinguish damaged bases from normal bases to prevent the inadvertent removal of normal bases, which would promote genomic instability. The mechanisms by which this high level of specificity is accomplished are as yet unresolved. One member of the uracil-DNA glycosylase family of repair enzymes, Escherichia coli mismatch-specific uracil-DNA glycosylase (Mug), is reported to distinguish U:G mispairs from U:A base pairs based upon specific contacts with the mispaired guanine after flipping the target uracil out of the duplex. However, recent studies suggest other mechanisms for base selection, including local duplex stability. In this study, we used the modified base N6-methyladenine to probe the effect of local helix perturbation on Mug recognition of uracil. N6-Methyladenine is found in E. coli as part of both the mismatch repair and restriction-modification systems. In its cis isomer, N6-methyladenine destabilizes hydrogen bonding by interfering with pseudo-Watson-Crick base pairing. It is observed that the selection of uracil by Mug is sequence dependent and that uracil residues in sequences of reduced thermostability are preferentially removed. The replacement of adenine by N6-methyladenine increases the frequency of removal of the uracil residue paired opposite the modified adenine. These results are in accord with suggestions that local helix stability is an important determinant of base recognition by some DNA repair enzymes and provide a potential strategy for identifying the sequence location of modified bases in DNA.
What is the role of mismatched uracil glycosylase (Mug) in DNA repair?
One member of the uracil-DNA glycosylase family of repair enzymes, Escherichia coli mismatch-specific uracil-DNA glycosylase (Mug), is reported to distinguish U:G mispairs from U:A base pairs based upon specific contacts with the mispaired guanine after flipping the target uracil out of the duplex.
The budding yeast Saccharomyces cerevisiae has contributed significantly to our current understanding of eukaryotic cell biology. It served as a tool and model for unraveling the molecular basis of a wide variety of cellular phenomena, which seem to be conserved in other organisms. During the last decade, yeast has also extensively been used to study the mechanisms underlying several human diseases, including age-associated neurodegenerative disorders, such as Parkinson's, Huntington's and Alzheimer's disease. In this review, we focus on a yeast model for synucleinopathies and summarize recent studies that not only provided new clues on how the misfolding of alpha-synuclein (alpha-syn) triggers toxicity and eventually cell death, but that also led to the identification of conserved suppressor proteins, which are effective in protecting cells, including neurons, from the alpha-syn-induced cytotoxicity.
Please summarize the relationship between a-syn and cell death.
In this review, we focus on a yeast model for synucleinopathies and summarize recent studies that not only provided new clues on how the misfolding of alpha-synuclein (alpha-syn) triggers toxicity and eventually cell death, but that also led to the identification of conserved suppressor proteins, which are effective in protecting cells, including neurons, from the alpha-syn-induced cytotoxicity.
Chromatin immunoprecipitation (ChIP) is the gold-standard technique for localizing nuclear proteins in the genome. We used ChIP, in combination with deep sequencing (Seq), to study the genome-wide distribution of the Silent information regulator (Sir) complex in Saccharomyces cerevisiae. We analyzed ChIP-Seq peaks of the Sir2, Sir3, and Sir4 silencing proteins and discovered 238 unexpected euchromatic loci that exhibited enrichment of all three. Surprisingly, published ChIP-Seq datasets for the Ste12 transcription factor and the centromeric Cse4 protein indicated that these proteins were also enriched in the same euchromatic regions with the high Sir protein levels. The 238 loci, termed "hyper-ChIPable", were in highly expressed regions with strong polymerase II and polymerase III enrichment signals, and the correlation between transcription level and ChIP enrichment was not limited to these 238 loci but extended genome-wide. The apparent enrichment of various proteins at hyper-ChIPable loci was not a consequence of artifacts associated with deep sequencing methods, as confirmed by ChIP-quantitative PCR. The localization of unrelated proteins, including the entire silencing complex, to the most highly transcribed genes was highly suggestive of a technical issue with the immunoprecipitations. ChIP-Seq on chromatin immunoprecipitated with a nuclear-localized GFP reproduced the above enrichment in an expression-dependent manner: induction of the GAL genes resulted in an increased ChIP signal of the GFP protein at these loci, with presumably no biological relevance. Whereas ChIP is a broadly valuable technique, some published conclusions based upon ChIP procedures may merit reevaluation in light of these findings.
Does Chromatin Immunoprecipitation (ChIP) show a bias for highly expressed loci?
The localization of unrelated proteins, including the entire silencing complex, to the most highly transcribed genes was highly suggestive of a technical issue with the immunoprecipitations
Tumor treating fields (TTFields) is a noninvasive, regional antimitotic treatment modality that has been approved for the treatment of recurrent glioblastoma by the U.S. FDA and has a CE mark in Europe. TTFields therapy delivers low-intensity (1-3 V/cm), intermediate-frequency (100-300 kHz), alternating electric fields to the tumor using transducer arrays placed on the skin around the region of the body containing the tumor. TTFields therapy affects metaphase, by disrupting mitotic spindle formation, and anaphase, by dielectrophoretic dislocation of intracellular constituents, resulting in apoptosis. TTFields therapy is frequency tuned to specific cancer cell types. The antimitotic effect of TTFields therapy has been demonstrated in multiple cell lines when the appropriate frequency was utilized. A phase III trial of TTFields monotherapy compared to active chemotherapy in recurrent glioblastoma patients established that TTFields therapy is associated with minimal toxicity, better quality of life, and comparable efficacy to chemotherapy. Ongoing and future trials will evaluate TTFields in newly diagnosed glioblastoma, solid tumor brain metastases, nonsmall cell lung cancer, and ovarian and pancreatic cancers.
Tumor-treating fields are effective for treatment of which cancers?
Tumor treating fields (TTFields) is a noninvasive, regional antimitotic treatment modality that has been approved for the treatment of recurrent glioblastoma by the U.S. FDA and has a CE mark in Europe.
Biologic disease-modifying anti-rheumatic drugs (bDMARDs) are used in pregnant patients with rheumatic diseases. Long-term follow-up data about newborns exposed to bDMARDs during pregnancy are however scarce. Here we summarize the published evidence and available recommendations for use of bDMARDs during pregnancy. We analyse clinical features at birth and at follow-up of 84 children, including: 16 consecutive children born to mothers with autoimmune diseases exposed to bDMARDs in utero; 32 children born to mothers with autoimmune diseases who did not receive bDMARDs; 36 children born to healthy mothers. In our monocentric cohort, children born to mothers with autoimmune diseases had lower gestational age at birth compared to those born to healthy mothers, independently of exposure to bDMARDs. At multivariate analysis, prematurity was an independent predictor of the need for antibiotic treatment, but not for hospitalisation or neonatal intensive care unit (ICU) stay during the neonatal period. Exposure to bDMARDs during pregnancy does not seem to interfere with post-natal development up to infancy. Prospective studies are needed in larger cohorts of pregnant patients to confirm that bDMARDs do not have a negative impact on psychomotor achievements in newborns.
Does the use of bDMARDs during pregnancy impact neonatal development?
Exposure to bDMARDs during pregnancy does not seem to interfere with post-natal development up to infancy.
In both mammalian and Drosophila spermatids, the completely histone-based chromatin structure is reorganized to a largely protamine-based structure. During this histone-to-protamine switch, transition proteins are expressed, for example TNP1 and TNP2 in mammals and Tpl94D in Drosophila. Recently, we demonstrated that in Drosophila spermatids, H3K79 methylation accompanies histone H4 hyperacetylation during chromatin reorganization. Preceding the histone-to-protamine transition, the H3K79 methyltransferase Grappa is expressed, and the predominant isoform bears a C-terminal extension. Here, we show that isoforms of the Grappa-equivalent protein in humans, rats and mice, that is DOT1L, have a C-terminal extension. In mice, the transcript of this isoform was enriched in the post-meiotic stages of spermatogenesis. In human and mice spermatids, di- and tri-methylated H3K79 temporally overlapped with hyperacetylated H4 and thus accompanied chromatin reorganization. In rat spermatids, trimethylated H3K79 directly preceded transition protein loading on chromatin. We analysed the impact of bacterial infections on spermatid chromatin using a uropathogenic Escherichia coli-elicited epididymo-orchitis rat model and showed that these infections caused aberrant spermatid chromatin. Bacterial infections led to premature emergence of trimethylated H3K79 and hyperacetylated H4. Trimethylated H3K79 and hyperacetylated H4 simultaneously occurred with transition protein TNP1, which was never observed in spermatids of mock-infected rats. Upon bacterial infection, only histone-based spermatid chromatin showed abnormalities, whereas protamine-compacted chromatin seemed to be unaffected. Our results indicated that H3K79 methylation is a histone modification conserved in Drosophila, mouse, rat and human spermatids and may be a prerequisite for proper chromatin reorganization.
What is the general function of H3K79 methylation?
Our results indicated that H3K79 methylation is a histone modification conserved in Drosophila, mouse, rat and human spermatids and may be a prerequisite for proper chromatin reorganization.
X chromosome inactivation (XCI) is the transcriptional silencing of one X in female mammals, balancing expression of X genes between females (XX) and males (XY). In placental mammals non-coding XIST RNA triggers silencing of one X (Xi) and recruits a characteristic suite of epigenetic modifications, including the histone mark H3K27me3. In marsupials, where XIST is missing, H3K27me3 association seems to have different degrees of stability, depending on cell-types and species. However, the complete suite of histone marks associated with the Xi and their stability throughout cell cycle remain a mystery, as does the evolution of an ancient mammal XCI system. Our extensive immunofluorescence analysis (using antibodies against specific histone modifications) in nuclei of mammals distantly related to human and mouse, revealed a general absence from the mammalian Xi territory of transcription machinery and histone modifications associated with active chromatin. Specific repressive modifications associated with XCI in human and mouse were also observed in elephant (a distantly related placental mammal), as was accumulation of XIST RNA. However, in two marsupial species the Xi either lacked these modifications (H4K20me1), or they were restricted to specific windows of the cell cycle (H3K27me3, H3K9me2). Surprisingly, the marsupial Xi was stably enriched for modifications associated with constitutive heterochromatin in all eukaryotes (H4K20me3, H3K9me3). We propose that marsupial XCI is comparable to a system that evolved in the common therian (marsupial and placental) ancestor. Silent chromatin of the early inactive X was exapted from neighbouring constitutive heterochromatin and, in early placental evolution, was augmented by the rise of XIST and the stable recruitment of specific histone modifications now classically associated with XCI.
Which post-translational histone modifications are characteristic of constitutive heterochromatin?
In placental mammals non-coding XIST RNA triggers silencing of one X (Xi) and recruits a characteristic suite of epigenetic modifications, including the histone mark H3K27me3.
Genetic screening based on loss-of-function phenotypes is a powerful discovery tool in biology. Although the recent development of clustered regularly interspaced short palindromic repeats (CRISPR)-based screening approaches in mammalian cell culture has enormous potential, RNA interference (RNAi)-based screening remains the method of choice in several biological contexts. We previously demonstrated that ultracomplex pooled short-hairpin RNA (shRNA) libraries can largely overcome the problem of RNAi off-target effects in genome-wide screens. Here, we systematically optimize several aspects of our shRNA library, including the promoter and microRNA context for shRNA expression, selection of guide strands, and features relevant for postscreen sample preparation for deep sequencing. We present next-generation high-complexity libraries targeting human and mouse protein-coding genes, which we grouped into 12 sublibraries based on biological function. A pilot screen suggests that our next-generation RNAi library performs comparably to current CRISPR interference (CRISPRi)-based approaches and can yield complementary results with high sensitivity and high specificity.
What is CRISPRi?
Although the recent development of clustered regularly interspaced short palindromic repeats (CRISPR)-based screening approaches in mammalian cell culture
In Guadeloupe, there is an abnormally high frequency of atypical parkinsonism. Only one-third of the patients that develop parkinsonian symptoms were reported to present the classical features of idiopathic Parkinson disease and one-third a syndrome resembling progressive supranuclear palsy (PSP). The others were unclassifiable, according to established criteria. We carried out a cross-sectional study of 160 parkinsonian patients to: (i) define more precisely the clinical phenotypes of the PSP-like syndrome and the parkinsonism that was considered unclassifiable in comparison with previously known disorders; (ii) define the neuropsychological and brain imaging features of these patients; (iii) evaluate to what extent a candidate aetiological factor, the mitochondrial complex I inhibitor annonacin contained in the fruit and leaves of the tropical plant Annona muricata (soursop) plays a role in the neurological syndrome. Neuropsychological tests and MRI were used to classify the patients into those with Parkinson's disease (31%), Guadeloupean PSP-like syndrome (32%), Guadeloupean parkinsonism-dementia complex (PDC, 31%) and other parkinsonism-related disorders (6%). Patients with a PSP-like syndrome developed levodopa-resistant parkinsonism, associated with early postural instability and supranuclear oculomotor dysfunction. They differed, however, from classical PSP patients by the frequency of tremor (>50%), dysautonomia (50%) and the occurrence of hallucinations (59%). PDC patients had levodopa-resistant parkinsonism associated with frontosubcortical dementia, 52% of these patients had hallucinations, but, importantly, none had oculomotor dysfunction. The pattern of neuropsychological deficits was similar in both subgroups. Cerebral atrophy was seen in the majority of the PSP-like and PDC patients, with enlargement of the third ventricle and marked T2-hypointensity in the basal ganglia, particularly the substantia nigra. Consumption of soursop was significantly greater in both PSP-like and PDC patients than in controls and Parkinson's disease patients. In conclusion, atypical Guadeloupean parkinsonism comprises two forms of parkinsonism and dementia that differ clinically by the presence of oculomotor signs, but have similar cognitive profiles and neuroimaging features, suggesting that they may constitute a single disease entity, and both were similarly exposed to annonaceous neurotoxins, notably annonacin.
Describe clinical presentation of Parkinsonism with dementia of Guadeloupe syndrome.
Patients with a PSP-like syndrome developed levodopa-resistant parkinsonism, associated with early postural instability and supranuclear oculomotor dysfunction. They differed, however, from classical PSP patients by the frequency of tremor (>50%), dysautonomia (50%) and the occurrence of hallucinations (59%). PDC patients had levodopa-resistant parkinsonism associated with frontosubcortical dementia, 52% of these patients had hallucinations, but, importantly, none had oculomotor dysfunction.
RNA-based therapies, including RNA molecules as drugs and RNA-targeted small molecules, offer unique opportunities to expand the range of therapeutic targets. Various forms of RNAs may be used to selectively act on proteins, transcripts, and genes that cannot be targeted by conventional small molecules or proteins. Although development of RNA drugs faces unparalleled challenges, many strategies have been developed to improve RNA metabolic stability and intracellular delivery. A number of RNA drugs have been approved for medical use, including aptamers (e.g., pegaptanib) that mechanistically act on protein target and small interfering RNAs (e.g., patisiran and givosiran) and antisense oligonucleotides (e.g., inotersen and golodirsen) that directly interfere with RNA targets. Furthermore, guide RNAs are essential components of novel gene editing modalities, and mRNA therapeutics are under development for protein replacement therapy or vaccination, including those against unprecedented severe acute respiratory syndrome coronavirus pandemic. Moreover, functional RNAs or RNA motifs are highly structured to form binding pockets or clefts that are accessible by small molecules. Many natural, semisynthetic, or synthetic antibiotics (e.g., aminoglycosides, tetracyclines, macrolides, oxazolidinones, and phenicols) can directly bind to ribosomal RNAs to achieve the inhibition of bacterial infections. Therefore, there is growing interest in developing RNA-targeted small-molecule drugs amenable to oral administration, and some (e.g., risdiplam and branaplam) have entered clinical trials. Here, we review the pharmacology of novel RNA drugs and RNA-targeted small-molecule medications, with a focus on recent progresses and strategies. Challenges in the development of novel druggable RNA entities and identification of viable RNA targets and selective small-molecule binders are discussed. SIGNIFICANCE STATEMENT: With the understanding of RNA functions and critical roles in diseases, as well as the development of RNA-related technologies, there is growing interest in developing novel RNA-based therapeutics. This comprehensive review presents pharmacology of both RNA drugs and RNA-targeted small-molecule medications, focusing on novel mechanisms of action, the most recent progress, and existing challenges.
Describe the mechanism of action of Givosiran.
of RNA drugs have been approved for medical use, including aptamers (e.g., pegaptanib) that mechanistically act on protein target and small interfering RNAs (e.g., patisiran and givosiran) and antisense oligonucleotides (e.g., inotersen and golodirsen) that directly interfere with RNA targets. Furthermore, gui
Alzheimer's disease is the most common form of dementia in the elderly, and it is characterized by elevated brain iron levels and accumulation of copper and zinc in cerebral beta-amyloid deposits (e.g., senile plaques). Both ionic zinc and copper are able to accelerate the aggregation of Abeta, the principle component of beta-amyloid deposits. Copper (and iron) can also promote the neurotoxic redox activity of Abeta and induce oxidative cross-linking of the peptide into stable oligomers. Recent reports have documented the release of Abeta together with ionic zinc and copper in cortical glutamatergic synapses after excitation. This, in turn, leads to the formation of Abeta oligomers, which, in turn, modulates long-term potentiation by controlling synaptic levels of the NMDA receptor. The excessive accumulation of Abeta oligomers in the synaptic cleft would then be predicted to adversely affect synaptic neurotransmission. Based on these findings, we have proposed the "Metal Hypothesis of Alzheimer's Disease," which stipulates that the neuropathogenic effects of Abeta in Alzheimer's disease are promoted by (and possibly even dependent on) Abeta-metal interactions. Increasingly sophisticated pharmaceutical approaches are now being implemented to attenuate abnormal Abeta-metal interactions without causing systemic disturbance of essential metals. Small molecules targeting Abeta-metal interactions (e.g., PBT2) are currently advancing through clinical trials and show increasing promise as disease-modifying agents for Alzheimer's disease based on the "metal hypothesis."
PBT2 has been tested for which disorder?
Small molecules targeting Abeta-metal interactions (e.g., PBT2) are currently advancing through clinical trials and show increasing promise as disease-modifying agents for Alzheimer's disease based on the "metal hypothesis."
Analysis by molecular hybridization of the RNAs transcribed by a cell-free fraction from avocado infected with avocado sunblotch viroid (ASBV) demonstrated the presence of newly synthesized viroid-specific sequences, most of which were of the same polarity as the mature infectious viroid RNA. Treatment of the cell-free fraction with DNase reduced the total synthesis of RNA considerably, but it did not influence that of the ASBV-specific RNAs, indicating that the latter were transcribed on an RNA template. Inhibition studies with alpha-amanitin showed that the synthesis of ASBV-specific RNAs was not affected by concentrations of 1 and 200 micrograms/ml of the drug, which typically inhibit RNA polymerase II and III, respectively, from most animal and plant systems. These results suggest that either RNA polymerase I or an unidentified RNA polymerase activity resistant to alpha-amanitin, acting on an RNA template, plays a role in the replication of ASBV, whereas for the rest of the viroids studied so far it appears that RNA polymerase II is involved. Analysis by polycrylamide gel electrophoresis under partially and fully denaturing conditions of the ASBV-specific RNAs synthesized in vitro showed that they contain unit and longer than unit length viroid strands, probably associated in complexes with single- and double-stranded regions. The structural properties of these complexes are similar to those of the RNAs accumulating in vivo in viroid-infected tissues, which are the postulated replicative intermediates of the rolling-circle mechanism proposed for viroid synthesis.
Which RNA polymerase is used for the replication of viroids?
These results suggest that either RNA polymerase I or an unidentified RNA polymerase activity resistant to alpha-amanitin, acting on an RNA template, plays a role in the replication of ASBV, whereas for the rest of the viroids studied so far it appears that RNA polymerase II is involved.
The identification of the Philadelphia chromosome in cells from individuals with chronic myelogenous leukemia (CML) led to the recognition that the BCR-ABL tyrosine kinase causes CML. This in turn led to the development of imatinib mesylate, a clinically successful inhibitor of the BCR-ABL kinase. Incorporating the use of markers of BCR-ABL kinase inhibition into clinical trials led to the realization that imatinib-resistant kinase domain mutations are the major cause of relapse during imatinib therapy and the subsequent development of new inhibitors to treat CML patients. The development of imatinib validates an emerging paradigm in cancer, in which a tumor is defined by genetic abnormalities and effective therapies are developed that target events critical to the growth and survival of a specific tumor.
What tyrosine kinase, involved in a Philadelphia- chromosome positive chronic myelogenous leukemia, is the target of Imatinib (Gleevec)?
identification of the Philadelphia chromosome in cells from individuals with chronic myelogenous leukemia (CML) led to the recognition that the BCR-ABL tyrosine kinase causes CML. This in turn led to the development of imatinib mesylate, a clinically successful inhibitor of the BCR-ABL kinase
Amblyopia is a developmental disorder that affects the spatial vision of one or both eyes in the absence of an obvious organic cause; it is associated with a history of abnormal visual experience during childhood. Subtypes have been defined based on the purported etiology, namely, strabismus (misaligned eyes) and/or anisometropia (unequal refractive error). Here we consider the usefulness of these subclassifications.
Does Amblyopia affect the eye?
Amblyopia is a developmental disorder that affects the spatial vision of one or both eyes in the absence of an obvious organic cause; it is associated with a history of abnormal visual experience during childhood
A comparative biochemical analysis was performed using recombinant human protein kinase Chk2 (checkpoint kinase 2) expressed in bacteria and insect cells. Dephosphorylated, inactive, recombinant human Chk2 could be reactivated in a concentration-dependent manner. Despite distinct time-dependent autophosphorylation kinetics by monitoring the phosphorylation of amino acid residues T68, S19, S33/35, T432, in Chk2 wildtype and Chk2 mutants (T68A, T68D and Q69E) they gave identical specific activities. However, upon gel filtration of Chk2 wildtype and the mutants, only Chk2 wildtype and the T68D mutant led to the formation of a 'pure' dimer; dephosphorylated wildtype Chk2 eluted as a monomer. Transfection of HEK293 cells with Chk2 wildtype and Chk2 mutants in the absence or presence of DNA damage showed significant T68 phosphorylation already in the absence of DNA damaging reagents. Upon DNA damage, phosphorylation of additional Chk2 sites was observed (S19, S33/35). A comparison of ATM+/+ and ATM-/- cells with respect to phosphorylation of residues T68, S19, S33/35 in the absence and presence of DNA damage showed in all cases phosphorylation of T68, although signal intensity was increased ca. three-fold after DNA damage. Mass spectrometric analyses of human recombinant Chk2 isolated from bacteria and insect cells showed distinct differences. The number of phosphorylated residues in human recombinant Chk2 isolated from bacteria was 16, whereas in the case of the recombinant human Chk2 from insect cells it was 8. Except for phosphorylated amino acid T378 which was not found in the Chk2 isolated from bacteria, all other phosphorylated residues identified in human Chk2 from insect cells were present also in Chk2 from bacteria.
Which are the major intramolecular phosphorylation sites of human Chk2 involved in cell cycle control?
Transfection of HEK293 cells with Chk2 wildtype and Chk2 mutants in the absence or presence of DNA damage showed significant T68 phosphorylation already in the absence of DNA damaging reagents
Bone resorption requires the adhesion of osteoclasts to extracellular matrix (ECM) components, a process mediated by the alpha(v)beta(3) integrin. Following engagement with the ECM, integrin receptors signal via multiple downstream effectors, including the integrin-linked kinase (ILK). In order to characterize the physiological role of ILK in bone resorption, we generated mice with an osteoclast-specific Ilk gene ablation by mating mice with a floxed Ilk allele with TRAP-Cre transgenic mice. The TRAP-Cre mice specifically excised floxed alleles in osteoclasts, as revealed by crossing them with the ROSA26R reporter strain. Osteoclast-specific Ilk mutant mice appeared phenotypically normal, but histomorphometric analysis of the proximal tibia revealed an increase in bone volume and trabecular thickness. Osteoclast-specific Ilk ablation was associated with an increase in osteoclastogenesis both in vitro and in vivo. However, the mutant osteoclasts displayed a decrease in resorption activity as assessed by reduced pit formation on dentin slices in vitro and decreased serum concentrations of the C-terminal telopeptide of collagen in vivo. Interestingly, compound heterozygous mice in which one allele of Ilk and one allele of the beta(3) integrin gene were inactivated (ILK(+/-); beta(3) (+/-)) also had increased trabecular thickness, confirming that beta(3) integrin and Ilk form part of the same genetic cascade. Our results show that ILK is important for the function, but not the differentiation, of osteoclasts.
What are the effects of ILK ablation?
Our results show that ILK is important for the function, but not the differentiation, of osteoclasts.