Gene expression profiles of wild-type and PERK-deficient cells during activation of OXPHOS
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE113572 | GEO | 2020/02/03
REPOSITORIES: GEO
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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.
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Project description:Gene expression profiles of wild-type and PERK-deficient cells during activation of OXPHOS
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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.
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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. 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:ISR pathway activation signatures in MEFs: GCN2 and PERK
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Project description:It is now well-accepted that cancers co-opt the microenvironment to support their growth. However, the molecular mechanisms underlying cancer-microenvironment interactions remain poorly defined. We have found that Rho-associated kinase (ROCK) activity in the epithelial component of mammary tumors selectively actuates Protein kinase R-like endoplasmic reticulum kinase (Perk), causing the recruitment and persistent education of tumor-promoting cancer-associated fibroblasts (CAFs), a key component of the cancer microenvironment. Analysis of tumors from mice and human patients identified Cysteine-rich with EGF-like domains 2 (CRELD2), as the paracrine factor underlying PERK-mediated CAF-education downstream of ROCK. CRELD2 expression was found to be regulated by ATF4 downstream of the PERK pathway and knock-down of CRELD2 prevented tumor progression, demonstrating that the paracrine ROCK-PERK-ATF4-CRELD2 axis is a promoter of breast cancer progression and suggesting new therapeutic opportunities.
2020-05-27 | PXD018253 | Pride
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: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.
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Project description:Malignant carcinomas that recur following therapy are typically de-differentiated and multi-drug resistant (MDR). De-differentiated cancer cells acquire MDR by upregulating reactive oxygen species (ROS)-scavenging enzymes and drug efflux pumps, but how these genes are upregulated in response to de-differentiation is not known. Here, we examine this question by using global transcriptional profiling to identify ROS-induced genes that are already upregulated in de-differentiated cells, even in the absence of oxidative damage. Using this approach, we found that the Nrf2 transcription factor, which is the master regulator of cellular response to oxidative stress, is pre-activated in de-differentiated cells. In de-differentiated cells, Nrf2 is not activated by oxidation but rather through a non-canonical mechanism involving its phosphorylation by the ER membrane kinase PERK. In contrast, differentiated cells require oxidative damage to activate Nrf2. Constitutive PERK-Nrf2 signaling protects de-differentiated cells from chemotherapy by reducing ROS levels and increasing drug efflux. These findings are validated in therapy-resistant basal breast cancer cell lines and animal models, where inhibition of the PERK-Nrf2 signaling axis reversed the MDR of de-differentiated cancer cells. Additionally, analysis of patient tumor datasets showed that a PERK pathway signature correlates strongly with chemotherapy resistance, tumor grade, and overall survival. Collectively, these results indicate that de-differentiated cells upregulate MDR genes via PERK-Nrf2 signaling, and suggest that targeting this pathway could sensitize drug-resistant cells to chemotherapy. Differentiated human breast epithelial cells (HMLE-shGFP) or de-differentiated cells (HMLE-Twist) were treated in culture with 40uM menadione for 2 hours or 1uM PERK inhibitor for 48 hours and compared to control DMSO-treated cells.
2014-10-01 | E-GEOD-59780 | biostudies-arrayexpress