PERK-dependent gene expression programs of the acute and chronic cellular response to ER stress
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PROVIDER: PRJNA486365 | ENA |
REPOSITORIES: ENA
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Project description:The UPR (Unfolded Protein Response) is a well-orchestrated response to ER protein folding and processing overload, integrating both transcriptional and translational outputs. Its three arms in mammalian cells, the PERK translational response arm, together with the ATF6 and IRE1-mediated transcriptional arms, have been thoroughly investigated. Using ribosome footprint profiling, we performed a deep characterization of the gene expression programs involved in the acute and adaptive ER stress responses. We utilized MEFs (Mouse Embryonic Fibroblasts) treated with Thapsigargin for different durations, that were wither WT or PERK knockouts, to determine the role of PERK in the acute and chronic UPR. We characterized three major gene expression programs: acute induction, chronic induction, and repression, and found that they were all PERK dependent. All three programs were recapitulated in publicly available data and in NIH3T3 cells. While PERK -/- cells did not recapitulate these responses in the acute timepoints, late timepoints showed an extremely weak induction/repression, suggesting that the chronic responses in WT cells are largely PERK dependent as well. We found that most ER target proteins were significantly repressed; including transmembrane proteins, glycoproteins, and proteins with disulfide bonds. We further demonstrate the downregulation of cyclins, while the expression of the amino acid biosynthesis pathway was enhanced.
2019-03-20 | GSE118660 | GEO
Project description:The spleen, as the prominent site for extramedullary myelopoiesis in cancer, generates significant amounts of myeloid cells to promote tumor progression. Cancer-associated splenic myelopoiesis is mediated by a population of functionally distinct hematopoietic stem/progenitor cells (HSPCs) that are committed to immunosuppressive myeloid cell generation, but the molecular mechanism regulating this response remains unclear. Here, we found that HSPCs in the spleen of tumor-bearing mice exhibited accelerated protein synthesis and engaged in a robust endoplasmic reticulum (ER) stress response. Single-cell RNA sequencing showed that the ER stress response was concomitant with the myeloid-biased lineage commitment and dysfunction of HSPCs in the spleen. PKR-like ER resident kinase (PERK), a molecular sensor of ER stress, directed HSPC differentiation into myeloid-derived suppressor cells (MDSCs) via PERK–eIF2α–ATF4–C/EBPβ signaling. Inhibition of this signaling prevented the emergence of granulocyte/macrophage colony-stimulating factor-expressing HSPCs in the spleen and disrupted the positive feedback-driven splenic myelopoiesis. Consequently, a blockade of PERK abated the suppressive function of tumor-infiltrating MDSCs and increased cytotoxic T cell infiltration, reshaping the tumor microenvironment to effectively suppress disease progression and potentiate both immuno- and targeted therapies. In accordance, activation of PERK–ATF4–C/EBPβ signaling was indispensable for the differentiation of human umbilical cord blood-derived HSPCs into functionally competent MDSCs. Together, these results indicate a crucial role for the cellular ER stress sensor PERK in modulating splenic HSPC activities in cancer, suggesting novel therapeutic opportunities for targeting the tumor-promoting myeloid response at its source. Raw data are available on Genome Sequence Archive, Bioproject accession number: PRJCA003519
2022-03-04 | GSE158486 | GEO
Project description:Disruptions of the endoplasmic reticulum (ER) that perturb protein folding cause ER stress and elicit an unfolded protein response (UPR) that involves translational and transcriptional changes in gene expression aimed at expanding the ER processing capacity and alleviating cellular injury. Three ER stress sensors PERK, ATF6, and IRE1 implement the UPR. PERK phosphorylation of eIF2 during ER stress represses protein synthesis, which prevents further influx of ER client proteins, along with preferential translation of ATF4, a transcription activator of the integrated stress response. In this study we show that the PERK/eIF2α~P/ATF4 pathway is required not only for translational control, but also activation of ATF6 and its target genes. The PERK pathway facilitates both the synthesis of ATF6 and trafficking of ATF6 from the ER to the Golgi for intramembrane proteolysis and activation of ATF6. As a consequence, liver-specific depletion of PERK significantly reduces both the translational and transcriptional phases of the UPR, leading to reduced protein chaperone expression, disruptions of lipid metabolism, and enhanced apoptosis. These findings show that the regulatory networks of the UPR are fully integrated, and helps explain the diverse pathologies associated with loss of PERK. 14 gene expression arrays, 3 WT control arrays; 3 lsPERK control arrays; 4 WT Treated arrays; 4 lsPERK treated arrays. Comparison of gene expression profiles for treated vs control in wildtype and knock-out.
2012-01-20 | E-GEOD-29929 | biostudies-arrayexpress
Project description:To identify the target genes of integrated stress reponse (ISR), we have employed whole genome microarray expression in MEF cells. ISR gene setimation under ER stress condition using Perk -/-, Atf4 -/-, eIF2a S51A mutant, Fv2E-PERK MEF cells
2015-09-01 | E-GEOD-49598 | biostudies-arrayexpress
Project description:Disruptions of the endoplasmic reticulum (ER) that perturb protein folding cause ER stress and elicit an unfolded protein response (UPR) that involves translational and transcriptional changes in gene expression aimed at expanding the ER processing capacity and alleviating cellular injury. Three ER stress sensors PERK, ATF6, and IRE1 implement the UPR. PERK phosphorylation of eIF2 during ER stress represses protein synthesis, which prevents further influx of ER client proteins, along with preferential translation of ATF4, a transcription activator of the integrated stress response. In this study we show that the PERK/eIF2α~P/ATF4 pathway is required not only for translational control, but also activation of ATF6 and its target genes. The PERK pathway facilitates both the synthesis of ATF6 and trafficking of ATF6 from the ER to the Golgi for intramembrane proteolysis and activation of ATF6. As a consequence, liver-specific depletion of PERK significantly reduces both the translational and transcriptional phases of the UPR, leading to reduced protein chaperone expression, disruptions of lipid metabolism, and enhanced apoptosis. These findings show that the regulatory networks of the UPR are fully integrated, and helps explain the diverse pathologies associated with loss of PERK.
2012-01-20 | GSE29929 | GEO
Project description:In response to different cellular stressors, the ISR kinases, PERK, PKR, HRI and GCN2, activate downstream transcriptional programs. While the core ISR transcription program is well characterized, markers that are specific to each individual ISR kinase activation pathway are not known. To identify markers that are induced by PERK or GCN2, but not the other ISR kinases, we subjected WT, GCN2-/-, and PERK-/- MEFs to amino acid starvation (RPMI 1640 SILAC -Lys -Arg) or Thapsigargin (200nM) treatment for 6 hours to activate the GCN2 and PERK pathways, respectively and performed RNA sequencing.
2022-07-01 | GSE179559 | GEO
Project description:Here we report that the Th2 cytokine IL-4 and the tumor microenvironment activated protein kinase RNA-like ER kinase (PERK) ER stress signaling cascade to promote immunosuppressive M2 activation and proliferation. Lacking PERK signaling impeded mitochondrial respiration and lipid oxidation critical for M2 macrophages. In addition, PERK activation mediated the upregulation of PSAT1 and serine biosynthesis via the downstream transcription factor ATF4.
2022-01-01 | GSE165836 | GEO
Project description:The area of mitochondria in differentiated brown adipocytes is dramatically increased compared with that in brown pre-adipocytes. The ATP production is switched from the glycolysis pathway to the OXPHOS pathway during brown adipocyte differentiation. Endoplasmic reticulum (ER) is surrounded by mitochondria and the area of contact sites between mitochondria and the ER is increased. ER stress sensor PERK was phosphorylated during differentiation. To elucidate the mitochondria-ER crosstalk signaling mediated by PERK, RNA-sequencing analysis was performed using control siRNA- or PERK siRNA-transfected brown adipocytes.
2020-02-03 | GSE132598 | GEO
Project description:Disruptions of protein homeostasis in the endoplasmic reticulum (ER) elicit activation of the unfolded protein response (UPR), a translation- and transcription-coupled proteostatic stress response pathway. The primary translational control arm of the UPR is initiated by the PERK-dependent phosphorylation of eIF2α, leading to a large-scale reprogramming of translation and subsequent activation of an ATF4-mediated transcriptional program. It has remained challenging, however, to accurately evaluate the contribution of each component of the eIF2α/ATF4 pathway to the remodelling of transcription and translation. Here, we have used mouse embryonic fibroblasts containing either a knock-in of the non-phosphorylatable eIF2α S51A mutant or knock-out for ATF4 by ribosome profiling and mRNA-seq to define the specific contributions of eIF2α phosphoryation and ATF4 in controlling the translational and transcriptional components of the UPR. These studies show that the transcriptional and translational targets of each P-eIF2α, ATF4, and the other UPR gene expression programs overlapped extensively, leading to a core set of UPR genes whose robust expression in response to ER stress is driven by multiple mechanisms. The identification of other, more factor-specific targets illustrated the potential for functional specialization of the UPR. As the UPR progressed temporally, cells employed distinct combinations of transcriptional and translational mechanisms, initiated by different factors, to adapt to ongoing stress. These effects were accompanied by a buffering effect where changes in mRNA levels were coupled to opposing changes in ribosome loading, a property which makes cooperation between transcription and translation essential to confer robust protein expression. Translational analysis by ribosome profiling and mRNA-seq of PERK pathways mutants during the UPR. Mouse embryonic fibroblasts (MEFs) lacking components of the PERK pathway (eIF2a phosphorylation and ATF4) were subjected to ER stress and analyzed by ribosome profiling.
2016-07-03 | E-GEOD-68265 | biostudies-arrayexpress
Project description:Olfactory sensory neurons (OSNs) transform the stochastic choice of one out of >1000 olfactory receptor (OR) genes into precise and stereotyped axon targeting of OR-specific glomeruli in the olfactory bulb. Here, we show that the PERK arm of the unfolded protein response (UPR) regulates both the glomerular coalescence of like axons, and the specificity of their projections. Subtle differences in OR protein sequences lead to distinct patterns of endoplasmic reticulum (ER) stress during OSN development, converting OR identity into distinct gene expression signatures. We identify the transcription factor Ddit3 as a key effector of PERK signaling that maps OR-dependent ER signaling patterns to the transcriptional regulation of axon guidance and cell adhesion genes, instructing targeting precision. Our results extend the known functions of the UPR from a quality control pathway that protects cells from misfolded proteins, to a sensor of cellular identity that interprets physiological states to direct axon wiring.
2022-09-26 | GSE198886 | GEO