173 research outputs found
Tamoxifen for the treatment of myeloproliferative neoplasms: A Phase II clinical trial and exploratory analysis
Current therapies for myeloproliferative neoplasms (MPNs) improve symptoms but have limited effect on tumor size. In preclinical studies, tamoxifen restored normal apoptosis in mutated hematopoietic stem/progenitor cells (HSPCs). TAMARIN Phase-II, multicenter, single-arm clinical trial assessed tamoxifen’s safety and activity in patients with stable MPNs, no prior thrombotic events and mutated JAK2 V617F, CALR ins5 or CALR del52 peripheral blood allele burden ≥20% (EudraCT 2015-005497-38). 38 patients were recruited over 112w and 32 completed 24w-treatment. The study’s A’herns success criteria were met as the primary outcome (≥ 50% reduction in mutant allele burden at 24w) was observed in 3/38 patients. Secondary outcomes included ≥25% reduction at 24w (5/38), ≥50% reduction at 12w (0/38), thrombotic events (2/38), toxicities, hematological response, proportion of patients in each IWG-MRT response category and ELN response criteria. As exploratory outcomes, baseline analysis of HSPC transcriptome segregates responders and non-responders, suggesting a predictive signature. In responder HSPCs, longitudinal analysis shows high baseline expression of JAK-STAT signaling and oxidative phosphorylation genes, which are downregulated by tamoxifen. We further demonstrate in preclinical studies that in JAK2V617F+ cells, 4-hydroxytamoxifen inhibits mitochondrial complex-I, activates integrated stress response and decreases pathogenic JAK2-signaling. These results warrant further investigation of tamoxifen in MPN, with careful consideration of thrombotic risk
Cryo-EM structures of complex I from mouse heart mitochondria in two biochemically defined states.
Complex I (NADH:ubiquinone oxidoreductase) uses the reducing potential of NADH to drive protons across the energy-transducing inner membrane and power oxidative phosphorylation in mammalian mitochondria. Recent cryo-EM analyses have produced near-complete models of all 45 subunits in the bovine, ovine and porcine complexes and have identified two states relevant to complex I in ischemia-reperfusion injury. Here, we describe the 3.3-Å structure of complex I from mouse heart mitochondria, a biomedically relevant model system, in the 'active' state. We reveal a nucleotide bound in subunit NDUFA10, a nucleoside kinase homolog, and define mechanistically critical elements in the mammalian enzyme. By comparisons with a 3.9-Å structure of the 'deactive' state and with known bacterial structures, we identify differences in helical geometry in the membrane domain that occur upon activation or that alter the positions of catalytically important charged residues. Our results demonstrate the capability of cryo-EM analyses to challenge and develop mechanistic models for mammalian complex I
Mitochondrial complex I and cell death: a semi-automatic shotgun model
Mitochondrial dysfunction often leads to cell death and disease. We can now draw correlations between the dysfunction of one of the most important mitochondrial enzymes, NADH:ubiquinone reductase or complex I, and its structural organization thanks to the recent advances in the X-ray structure of its bacterial homologs. The new structural information on bacterial complex I provide essential clues to finally understand how complex I may work. However, the same information remains difficult to interpret for many scientists working on mitochondrial complex I from different angles, especially in the field of cell death. Here, we present a novel way of interpreting the bacterial structural information in accessible terms. On the basis of the analogy to semi-automatic shotguns, we propose a novel functional model that incorporates recent structural information with previous evidence derived from studies on mitochondrial diseases, as well as functional bioenergetics
Microsatellite Instability in Pediatric High Grade Glioma Is Associated with Genomic Profile and Differential Target Gene Inactivation
High grade gliomas (HGG) are one of the leading causes of cancer-related deaths in children, and there is increasing evidence that pediatric HGG may harbor distinct molecular characteristics compared to adult tumors. We have sought to clarify the role of microsatellite instability (MSI) in pediatric versus adult HGG. MSI status was determined in 144 patients (71 pediatric and 73 adults) using a well established panel of five quasimonomorphic mononucleotide repeat markers. Expression of MLH1, MSH2, MSH6 and PMS2 was determined by immunohistochemistry, MLH1 was assessed for mutations by direct sequencing and promoter methylation using MS-PCR. DNA copy number profiles were derived using array CGH, and mutations in eighteen MSI target genes studied by multiplex PCR and genotyping. MSI was found in 14/71 (19.7%) pediatric cases, significantly more than observed in adults (5/73, 6.8%; p = 0.02, Chi-square test). MLH1 expression was downregulated in 10/13 cases, however no mutations or promoter methylation were found. MSH6 was absent in one pediatric MSI-High tumor, consistent with an inherited mismatch repair deficiency associated with germline MSH6 mutation. MSI was classed as Type A, and associated with a remarkably stable genomic profile. Of the eighteen classic MSI target genes, we identified mutations only in MSH6 and DNAPKcs and described a polymorphism in MRE11 without apparent functional consequences in DNA double strand break detection and repair. This study thus provides evidence for a potential novel molecular pathway in a proportion of gliomas associated with the presence of MSI
Anticitrullinated protein antibody (ACPA) in rheumatoid arthritis: influence of an interaction between HLA-DRB1 shared epitope and a deletion polymorphism in glutathione s-transferase in a cross-sectional study
Abstract Introduction A deletion polymorphism in glutathione S-transferase Mu-1 (GSTM1-null) has previously been implicated to play a role in rheumatoid arthritis (RA) risk and progression, although no prior investigations have examined its associations with anticitrullinated protein antibody (ACPA) positivity. The purpose of this study was to examine the associations of GSTM1-null with ACPA positivity in RA and to assess for evidence of interaction between GSTM1 and HLA-DRB1 shared epitope (SE). Methods Associations of GSTM1-null with ACPA positivity were examined separately in two RA cohorts, the Veterans Affairs Rheumatoid Arthritis (VARA) registry (n = 703) and the Study of New-Onset RA (SONORA; n = 610). Interactions were examined by calculating an attributable proportion (AP) due to interaction. Results A majority of patients in the VARA registry (76%) and SONORA (69%) were positive for ACPA with a similar frequency of GSTM1-null (53% and 52%, respectively) and HLA-DRB1 SE positivity (76% and 71%, respectively). The parameter of patients who had ever smoked was more common in the VARA registry (80%) than in SONORA (65%). GSTM1-null was significantly associated with ACPA positivity in the VARA registry (odds ratio (OR), 1.45; 95% confidence interval (CI), 1.02 to 2.05), but not in SONORA (OR, 1.00; 95% CI, 0.71 to 1.42). There were significant additive interactions between GSTM1 and HLA-DRB1 SE in the VARA registry (AP, 0.49; 95% CI, 0.21 to 0.77; P < 0.001) in ACPA positivity, an interaction replicated in SONORA (AP, 0.38; 95% CI, 0.00 to 0.76; P = 0.050). Conclusions This study is the first to show that the GSTM1-null genotype, a common genetic variant, exerts significant additive interaction with HLA-DRB1 SE on the risk of ACPA positivity in RA. Since GSTM1 has known antioxidant functions, these data suggest that oxidative stress may be important in the development of RA-specific autoimmunity in genetically susceptible individuals
Life Cycle Management of Infrastructures
By definition, life cycle management (LCM) is a framework “of concepts, techniques, and procedures to address environmental, economic, technological, and social aspects of products and organizations in order to achieve continuous ‘sustainable’ improvement from a life cycle perspective” (Hunkeler et al.\ua02001). Thus, LCM theoretically integrates all sustainability dimensions, and strives to provide a holistic perspective. It also assists in the efficient and effective use of constrained natural and financial resources to reduce negative impacts on society (Sonnemann and Leeuw\ua02006; Adibi et al.\ua02015). The LCM of infrastructures is the adaptation of product life cycle management (PLM) as techniques to the design, construction, and management of infrastructures. Infrastructure life cycle management requires accurate and extensive information that might be generated through different kinds of intelligent and connected information workflows, such as building information modeling (BIM)
Neurostimulatory and ablative treatment options in major depressive disorder: a systematic review
Introduction Major depressive disorder is one of the most disabling and common diagnoses amongst psychiatric disorders, with a current worldwide prevalence of 5-10% of the general population and up to 20-25% for the lifetime period. Historical perspective Nowadays, conventional treatment includes psychotherapy and pharmacotherapy; however, more than 60% of the treated patients respond unsatisfactorily, and almost one fifth becomes refractory to these therapies at long-term follow-up. Nonpharmacological techniques Growing social incapacity and economic burdens make the medical community strive for better therapies, with fewer complications. Various nonpharmacological techniques like electroconvulsive therapy, vagus nerve stimulation, transcranial magnetic stimulation, lesion surgery, and deep brain stimulation have been developed for this purpose. Discussion We reviewed the literature from the beginning of the twentieth century until July 2009 and described the early clinical effects and main reported complications of these methods. © The Author(s) 2010.Link_to_subscribed_fulltex
AAV Exploits Subcellular Stress Associated with Inflammation, Endoplasmic Reticulum Expansion, and Misfolded Proteins in Models of Cystic Fibrosis
Barriers to infection act at multiple levels to prevent viruses, bacteria, and parasites from commandeering host cells for their own purposes. An intriguing hypothesis is that if a cell experiences stress, such as that elicited by inflammation, endoplasmic reticulum (ER) expansion, or misfolded proteins, then subcellular barriers will be less effective at preventing viral infection. Here we have used models of cystic fibrosis (CF) to test whether subcellular stress increases susceptibility to adeno-associated virus (AAV) infection. In human airway epithelium cultured at an air/liquid interface, physiological conditions of subcellular stress and ER expansion were mimicked using supernatant from mucopurulent material derived from CF lungs. Using this inflammatory stimulus to recapitulate stress found in diseased airways, we demonstrated that AAV infection was significantly enhanced. Since over 90% of CF cases are associated with a misfolded variant of Cystic Fibrosis Transmembrane Conductance Regulator (ΔF508-CFTR), we then explored whether the presence of misfolded proteins could independently increase susceptibility to AAV infection. In these models, AAV was an order of magnitude more efficient at transducing cells expressing ΔF508-CFTR than in cells expressing wild-type CFTR. Rescue of misfolded ΔF508-CFTR under low temperature conditions restored viral transduction efficiency to that demonstrated in controls, suggesting effects related to protein misfolding were responsible for increasing susceptibility to infection. By testing other CFTR mutants, G551D, D572N, and 1410X, we have shown this phenomenon is common to other misfolded proteins and not related to loss of CFTR activity. The presence of misfolded proteins did not affect cell surface attachment of virus or influence expression levels from promoter transgene cassettes in plasmid transfection studies, indicating exploitation occurs at the level of virion trafficking or processing. Thus, we surmised that factors enlisted to process misfolded proteins such as ΔF508-CFTR in the secretory pathway also act to restrict viral infection. In line with this hypothesis, we found that AAV trafficked to the microtubule organizing center and localized near Golgi/ER transport proteins. Moreover, AAV infection efficiency could be modulated with siRNA-mediated knockdown of proteins involved in processing ΔF508-CFTR or sorting retrograde cargo from the Golgi and ER (calnexin, KDEL-R, β-COP, and PSMB3). In summary, our data support a model where AAV exploits a compromised secretory system and, importantly, underscore the gravity with which a stressed subcellular environment, under internal or external insults, can impact infection efficiency
Pichia pastoris regulates its gene-specific response to different carbon sources at the transcriptional, rather than the translational, level
Background: The methylotrophic, Crabtree-negative yeast Pichia pastoris is widely used as a heterologous protein production host. Strong inducible promoters derived from methanol utilization genes or constitutive glycolytic promoters are typically used to drive gene expression. Notably, genes involved in methanol utilization are not only repressed by the presence of glucose, but also by glycerol. This unusual regulatory behavior prompted us to study the regulation of carbon substrate utilization in different bioprocess conditions on a genome wide scale. Results: We performed microarray analysis on the total mRNA population as well as mRNA that had been fractionated according to ribosome occupancy. Translationally quiescent mRNAs were defined as being associated with single ribosomes (monosomes) and highly-translated mRNAs with multiple ribosomes (polysomes). We found that despite their lower growth rates, global translation was most active in methanol-grown P. pastoris cells, followed by excess glycerol- or glucose-grown cells. Transcript-specific translational responses were found to be minimal, while extensive transcriptional regulation was observed for cells grown on different carbon sources. Due to their respiratory metabolism, cells grown in excess glucose or glycerol had very similar expression profiles. Genes subject to glucose repression were mainly involved in the metabolism of alternative carbon sources including the control of glycerol uptake and metabolism. Peroxisomal and methanol utilization genes were confirmed to be subject to carbon substrate repression in excess glucose or glycerol, but were found to be strongly de-repressed in limiting glucose-conditions (as are often applied in fed batch cultivations) in addition to induction by methanol. Conclusions: P. pastoris cells grown in excess glycerol or glucose have similar transcript profiles in contrast to S. cerevisiae cells, in which the transcriptional response to these carbon sources is very different. The main response to different growth conditions in P. pastoris is transcriptional; translational regulation was not transcript-specific. The high proportion of mRNAs associated with polysomes in methanol-grown cells is a major finding of this study; it reveals that high productivity during methanol induction is directly linked to the growth condition and not only to promoter strength
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