HIV-1 nucleoside reverse transcriptase inhibitor (NRTI) use is associated with severe adverse events. However, the exact mechanisms behind their toxicity has not been fully understood. Mitochondrial dysfunction after chronic exposure to NRTIs has predominantly been assigned to mitochondrial polymerase-? inhibition by NRTIs. However, an increasing amount of data suggests that this is not the sole mechanism. Many NRTI induced adverse events have been linked to the incurrence of oxidative stress, although the causality of events leading to reactive oxygen species (ROS) production and their role in toxicity is unclear. In this study we show that short-term effects of these drugs, which are rarely discussed in the literature, include direct inhibition of the mitochondrial respiratory chain (MRC), decreased ATP levels and increased ROS production. Collectively these events affect fitness and longevity of C. elegans through mitohormetic signalling events. Furthermore, we demonstrate that these effects can be normalized by addition of the anti-oxidant N-acetylcysteine (NAC), which suggests that ROS likely influence the onset and severity of adverse events upon drug exposure. Overall design: RNA-seq on Caenorhabditis elegans exposed to DMSO, 3''-azido-3''-deoxythymidine (zidovudine or AZT), 2'',3''-didehydro-2'',3''-deoxythymidine (stavudine or d4T), 3''-deoxy-3''-fluorothymidine (alovudine or FLT) or untreated control after 24 or 72 hours of exposure.
Beyond the polymerase-γ theory: Production of ROS as a mode of NRTI-induced mitochondrial toxicity.
Specimen part, SubjectView Samples
The liver is one of the most sexually dimorphic organs as measured by gene expression differences. About 80% of the sexually dimorphic genes are known to be regulated by growth hormone (GH). Somatostatin (SST) inhibits the release of GH.
Somatostatin is essential for the sexual dimorphism of GH secretion, corticosteroid-binding globulin production, and corticosterone levels in mice.
Sex, Specimen partView Samples
Surfactant deficiency, diffuse alveolar damage and respiratory failure caused by loss of Abca3 in AT2 cells was followed by remarkable proliferation of alveolar cells and selective survival of ABCA3 sufficient cells resulting in regeneration of alveolar structure and function, providing the conceptual framework for the development of therapies to ameliorate lung diseases caused by mutations in ABCA3 and other genes critical for AT2 cell function or surfactant homeostasis. Overall design: Control and Abca3 cKO AT2 cell RNA-seq at 6 days post tamoxifen in adult mice.
Alveolar injury and regeneration following deletion of ABCA3.
Specimen part, SubjectView Samples
Recent observations about how cells sense amino acids have argued for preeminent roles of mTOR and the stress kinase GCN2 in allowing cells to estimate their amino acid needs. Here we used models of programmed immune microenvironments where helper T cells have to sense how much amino acids are available to engage in antigen-fueled proliferation. Contrary to current models, T cells activate mTOR in the competency phase of the cell cycle regardless of amino acid amounts, GCN2 or surface TCR. Instead, we found T cells use an amino acid sensing system to target IL-2-induced STAT5 phosphorylation at the restriction point of cell cycle commitment. mTOR activity is subsequently reduced and specifically connected to SREBP activation. T cells can be pushed into cycle by increasing IL-2 even when no amino acids are available. Collectively, our studies reveal helper T cells use sequential and distinct pathways to measure local amino acid concentrations.
Proliferating Helper T Cells Require Rictor/mTORC2 Complex to Integrate Signals from Limiting Environmental Amino Acids.
Specimen part, TreatmentView Samples
Integrins facilitate intercellular movement and communication. Unlike the promiscuous activities of many integrins, 6 integrin is restricted to epithelia and partners exclusively with integrin V to modulate acute lung injury (ALI). Given that ALI is a complication of respiratory infection, we used mice lacking 6 integrin (6 KO) to probe the role of the epithelial layer in controlling the lung microenvironment during infection. We found 6 KO mice were protected from disease caused by influenza and Sendai virus infections. They were also protected from disease caused by Streptococcus pneumoniae infection alone and after prior influenza virus infection, the co-infection representing an often-lethal condition in humans. Resistance in the absence of epithelial 6 integrin was caused by intrinsic priming of the lung microenvironment by type I interferons through a mechanism involving transforming growth factor- regulation. Expression of 6 on epithelia suppresses the production of interferons, providing an advantage to the pathogen. Acute inhibition of 6 function may therefore provide a means to improve outcomes in lung microbial infections.
An Epithelial Integrin Regulates the Amplitude of Protective Lung Interferon Responses against Multiple Respiratory Pathogens.
Specimen partView Samples
Long term exposure to incretin hormones is known to have salutory effects on beta cell function and viability. While short-term cAMP induction is known to have a signature CREB-CRTC target gene response, the long-term effects of cAMP on beta cell gene expression are less well understood.
mTOR links incretin signaling to HIF induction in pancreatic beta cells.
Cell line, TimeView Samples
These arrays contain data from hypthalamus tissue of nestin-Pex5 -/- male mice
Peroxisome deficiency but not the defect in ether lipid synthesis causes activation of the innate immune system and axonal loss in the central nervous system.
Specimen partView Samples
The results of this study indicate that stenotic fibroblasts exhibit an aberrant response to tissue stiffness with reduced MMP activity, leading to a perpetuous vicious circle of ever more fibrosis formation. Altering the microenvironment by LOX inhibition increases MMP activity and decreases ECM contraction, resulting in a potential anti-fibrotic agent for Crohns disease.
Fibrostenotic Phenotype of Myofibroblasts in Crohn's Disease is Dependent on Tissue Stiffness and Reversed by LOX Inhibition.
Sex, Specimen part, Disease, SubjectView Samples
Almost a quarter of pediatric patients with Acute Lymphoblastic Leukemia (ALL) suffer from relapses. The biological mechanisms underlying therapy response and development of relapses have remained unclear. In an attempt to better understand this phenomenon, we have analyzed 41 matched diagnosis relapse pairs of ALL patients using genomewide expression arrays (82 arrays) on purified leukemic cells. In roughly half of the patients very few differences between diagnosis and relapse samples were found (stable group), suggesting that mostly extra-leukemic factors (e.g., drug distribution, drug metabolism, compliance) contributed to the relapse. Therefore, we focused our further analysis on 20 samples with clear differences in gene expression (skewed group), reasoning that these would allow us to better study the biological mechanisms underlying relapsed ALL. After finding the differences between diagnosis and relapse pairs in this group, we identified four major gene clusters corresponding to several pathways associated with changes in cell cycle, DNA replication, recombination and repair, as well as B cell developmental genes. We also identified cancer genes commonly associated with colon carcinomas and ubiquitination to be upregulated in relapsed ALL. Thus, about half of relapses are due to selection or emergence of a clone with deregulated expression of a genes involved in pathways that regulate B cell signaling, development, cell cycle, cellular division and replication.
Genome-wide expression analysis of paired diagnosis-relapse samples in ALL indicates involvement of pathways related to DNA replication, cell cycle and DNA repair, independent of immune phenotype.
Sex, Specimen part, DiseaseView Samples
This SuperSeries is composed of the SubSeries listed below.
Drug-induced histone eviction from open chromatin contributes to the chemotherapeutic effects of doxorubicin.
Age, Specimen part, Cell line, Treatment, TimeView Samples