Stress response factor ATF4 drives liver fibrosis by governing a stress-independent enhancer program to activate hepatic stellate cells
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ABSTRACT:
PROVIDER: PRJNA987623 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR25030502_1.fastq.gz | Fastqsanger.gz | |||
| SRR25030502_2.fastq.gz | Fastqsanger.gz | |||
| SRR25030503_1.fastq.gz | Fastqsanger.gz | |||
| SRR25030503_2.fastq.gz | Fastqsanger.gz | |||
| SRR25030504_1.fastq.gz | Fastqsanger.gz |
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Project description:ATF4 promotes HSC activation and drives liver fibrosis independent of its canonical functions in stress signaling.
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Project description:Cellular redox control is maintained by generation of reactive oxygen/nitrogen species balanced by activation of antioxidative pathways. Disruption of redox balance leads to oxidative stress, a central causative event in numerous diseases including heart failure. Redox control in the heart exposed to hemodynamic stress, however, remains to be fully elucidated. Here, we show that production of cardiomyocyte NADPH (nicotinamide adenine dinucleotide phosphate), a key factor in redox regulation, is decreased in pressure overload-induced heart failure. As a consequence, the level of reduced glutathione is downregulated, a change associated with cardiac cell death, fibrosis, and cardiomyopathy. We report that the pentose phosphate pathway (PPP) and mitochondrial serine/glycine/folate metabolic signaling, two major NADPH-generating pathways in the cytosol and mitochondria, respectively, are induced in the heart by pressure overload. We identify ATF4 (activating transcriptional factor 4) as an upstream transcription factor controlling the expression of multiple enzymes in these two pathways. Consistent with this, joint pathway analysis (JPA) of transcriptomic and metabolomic data reveals that ATF4 preferably controls oxidative stress and redox-related pathways. Overexpression of ATF4 in cardiomyocytes in culture leads to a significant increase in NADPH-producing enzymes whereas silencing of ATF4 decreases their expression. Further, stable isotope tracer experiments reveal that ATF4 overexpression in vitro strongly augments metabolic flux within these two pathways. In vivo, cardiomyocyte-specific deletion of ATF4 exacerbates cardiomyopathy in the setting of pressure overload and accelerates the development of heart failure, attributable, at least in part, to an inability to increase the expression of NADPH-generating enzymes. Taken together, our findings reveal that ATF4 plays a critical role in cardiac homeostasis under conditions of hemodynamic stress by governing both cytosolic and mitochondrial production of NADPH.
2022-05-16 | GSE187005 | GEO
Project description:To further development of our miRNA expression approach to ER stress, we have employed miRNA microarray expression profiling as a discovery platform to identify ER stress-responsible ones. Mouse embryonic fibroblasts (MEFs) deficient in a ER stress mediator ATF4 were treated with tunicamycin for 12 or 24 hrs. miRNAs responsible for tunicamycin-treatment for 12hrs in ATF4-dependent manner were extracted. Among them, expression of three miRNAs (miR-193b, miR-423-5p, miR-199a-3p) was quantified in the RNA samples from the same as the microarray by real-time PCR. Mouse embryonic fibroblasts (MEFs) deficient in a ER stress mediator ATF4 were treated with 2ug/mL tunicamycin for 12 or 24 hrs. Two independent experiments were performed at each time (untreated, 12 or 24 hrs). miRNAs responsible for tunicamycin-treatment for 12hrs in ATF4-dependent manner were extracted.
2015-01-18 | E-GEOD-35175 | biostudies-arrayexpress
Project description:Oxidative stress is pathogenic in neurological diseases including stroke. The identity of oxidative stress-inducible transcription factors and their role(s) in propagating the death cascade are poorly understood. Microarray analysis of neurons undergoing oxidative stress showed significant induction of prodeath genes. These genes have been shown to be regulated by the bZip transcription factor, ATF4. ATF4 protein localized to the promoter of a putative death gene in neurons in vitro and in vivo. Germline deletion of ATF4 in neurons resulted in a reduction in oxidative stress-induced gene expression and resistance to oxidative death. ATF4 knockout mice experienced significantly smaller infarcts and improved behavioral recovery as compared to wild-type mice subjected to the same reductions in blood flow in a rodent model of stroke. ATF4 modulates an early, upstream event in the death pathway, as resistance to oxidative death by ATF4 deletion was associated with decreased consumption of the antioxidant glutathione. Restoration of ATF4 protein in knockout neurons was sufficient to restore sensitivity to oxidative death and to reaccelerate loss of glutathione. Together, these findings establish ATF4 as a redox-regulated, pro-death transcriptional activator in the nervous system that propagates death responses to oxidative stress in vitro and to stroke in vivo. Keywords: ATF4, oxidative stress, gene expression, neuroprotection, stroke WT and ATF4 KO embryonic neurons were studied. Untreated neurons (no=8 per genotype) and neurons challenged with oxidative stress with the glutamate homolog homocysteate (HCA, no=4 per genotype) were studied, for a total of 24 samples.
2010-06-25 | E-GEOD-10470 | biostudies-arrayexpress
Project description:Translation efficiency varies 1000-fold between different mRNAs, thereby strongly impacting protein expression. Translation of the master stress response gene ATF4 increases in response to stress, but the molecular mechanisms are not well understood. We discover here that translation initiation factors DENR, MCTS1 and eIF2D are absolutely required to induce ATF4 translation upon stress, by promoting translation reinitiation on the ATF4 5’UTR. Hence DENR and MCTS1 are important players in the cellular Integrated Stress Response. We find DENR and MCTS1 promote reinitiation after long uORFs with specific penultimate codons, due to the tRNA that remains attached to 40S ribosomes after translation termination. This provides a model for how DENR and MCTS1 promote translation reinitiation. Since cancer cells are exposed to many stresses, they require ATF4 for survival and proliferation. We find a strong correlation between DENR•MCTS1 expression and ATF4 activity across cancers. Additional oncogenes including a-Raf, c-Raf and Cdk4 have long uORFs and are translated in a DENR•MCTS1 dependent manner. This explains in part why DENR and MCTS1 are oncogenes.
2020-07-18 | GSE140084 | GEO
Project description:We report the direct target genes of ATF4 and CHOP in response to endoplasim reticulum stress through next generation sequencing. By obtaining genowide sequence from chromatin immunoprecipitated DNA with anti-CHOP and anit-ATF4, we identified direct binding sites of ATF4 and CHOP in promoter regions of their target genes in mouse embrynic fibroblasts (MEFs) in response to ER stress. In addition, we obtained list of genes which are differentially regulated in Atf4 or Chop-deficient MEFs compared to the wild-type MEFs in response to ER stress. We found that genes related with unfolded protein response and protein synthesis were directly regulated by ATF4 and CHOP. Through this observation, we conclude that main role of ATF4 and CHOP as transcription factors is to enhance mRNA translation in respone to ER stress. This sutdy provide new insight of genetic network of ATF4 and CHOP in response to ER stress. For ChIP-seq, Chop+/+ and Chop-/- MEFs were treated with Tunicamycin, N-glycosylation inhibitor, to induce ER stress for 8hr. Atf4+/+ and Atf4-/- MEFs were also treated same condition for ChIP-Seq. For mRNA-seq, wild-type, Atf4-/-, and Chop-/- MEFs were treated with tunicamycin for 8hr for experiments.
2013-04-11 | E-GEOD-35681 | biostudies-arrayexpress
Project description:Activating Transcription Factor 4 (ATF4) is a transcription factor induced by the integrated stress response (ISR). This experiment is a genome-wide profiling of ATF4-dependent RNA expression in human HAP-1 cells. HAP-1 is a near-haploid human cell line that was derived from KBM-7 cells isolated from a patient with Chronic Myelogenous Leukemia. We analyzed WT and ATF4 KO cells. We induced ATF4 expression by mimicking amino acid starvation with the drug histidinol. RNA expression profiles were generated for WT and ATF4 KO HAP1 cells. ATF4 genes were mutated using Cas9 genome editing technology. Amino acid starvation was mimicked by treating WT and ATF4 KO cells with 2 mM histidinol for 24 hours, which increases ATF4 expression.
2015-08-28 | E-GEOD-69308 | biostudies-arrayexpress
Project description:The ubiquitin-proteasome system (UPS) has recently emerged as a major target for drug development in cancer therapy. The proteasome inhibitor bortezomib has clinical activity in multiple myeloma and mantle cell lymphoma. Here we report that Eeyarestatin I (EerI), a chemical inhibitor that blocks ER-associated protein degradation (ERAD), has anti-tumor and biologic activities similar to bortezomib, and can synergize with bortezomib. Like bortezomib, EerI-induced cytotoxicity requires the upregulation of the BH3 only pro-apoptotic protein NOXA. We further demonstrate that both EerI and bortezomib activate NOXA via an unanticipated mechanism that requires cooperation between two processes: First, these agents elicit an integrated stress response program at the ER to activate the CREB/ATF transcription factors ATF3 and ATF4. We show that ATF3 and ATF4 form a complex capable of binding to the NOXA promoter, which is required for NOXA activation. Second, EerI and bortezomib also block ubiquitination of histone H2A to relieve its inhibition on NOXA transcription. Our results identify a class of anti-cancer agents that integrate ER stress response with an epigenetic mechanism to induce cell death.
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Project description:The integrated stress response (ISR) is a central signaling pathway induced by a variety of insults, but how its outputs contribute to downstream physiological effects across diverse cellular contexts remains unclear. Using a synthetic tool, we specifically and tunably activated the ISR and performed multi-omics profiling to define the core modules elicited by this response in the absence of co-activation of parallel pathways commonly induced by pleiotropic stressors. We found that the ISR can elicit time- and dose-dependent gene expression changes that cluster into four modules with ATF4 driving only a small but fast and sensitive module that includes many amino acid metabolic enzymes. We showed that ATF4 was required to reroute carbon utilization towards amino acid synthesis derived both from glucose and reductive carboxylation of glutamine and away from the tricarboxylic acid cycle and fatty acid biogenesis revealing a new role for ATF4 in modulating cellular energetics. We also discovered an ATF4-independent reorganization of cellular lipids that promotes triglycerides synthesis and accumulation of lipid droplets that was essential for cell survival. Together, we demonstrate that a minimal ISR-inducing system is sufficient to trigger formation of two distinct cellular structures, stress granules and lipid droplets, and a previously unappreciated metabolic state.
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