Regulated IRE1α-dependent decay (RIDD)-mediated reprograming of lipid metabolism in cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE176454 | GEO | 2022/02/28
REPOSITORIES: GEO
Similar Datasets
Project description:Regulated IRE1α-dependent decay (RIDD)-mediated reprograming of lipid metabolism in cancer
| PRJNA736320 | ENA
Project description:Eukaryotic IRE1 mitigates endoplasmic-reticulum (ER) stress by orchestrating the unfolded-protein response (UPR). IRE1 spans the ER membrane, and signals through a cytosolic kinase-endoribonuclease module. The endoribonuclease generates the transcription factor XBP1s by intron excision between similar RNA stem-loop endomotifs, and depletes select cellular mRNAs through regulated IRE1-dependent decay (RIDD). Paradoxically, mammalian RIDD seemingly targets only mRNAs with XBP1-like endomotifs, while in flies RIDD exhibits little sequence restriction. By comparing nascent and total IRE1α-controlled mRNAs in human breast cancer cells, we discovered not only canonical endomotif-containing RIDD substrates, but also many targets lacking recognizable motifs—degraded by a process we coin RIDDLE, for RIDD lacking endomotif. IRE1α displayed two basic endoribonuclease modalities: endomotif-specific cleavage, minimally requiring dimers; and endomotif-independent promiscuous processing, requiring phospho-oligomers. An oligomer-deficient mutant that did not support RIDDLE failed to rescue cancer-cell viability. These results link IRE1α oligomers, RIDDLE, and cell survival, advancing mechanistic understanding of the UPR.
2021-06-01 | GSE169583 | GEO
Project description:Eukaryotic IRE1 mitigates endoplasmic-reticulum (ER) stress by orchestrating the unfolded-protein response (UPR). IRE1 spans the ER membrane, and signals through a cytosolic kinase-endoribonuclease module. The endoribonuclease generates the transcription factor XBP1s by intron excision between similar RNA stem-loop endomotifs, and depletes select cellular mRNAs through regulated IRE1-dependent decay (RIDD). Paradoxically, mammalian RIDD seemingly targets only mRNAs with XBP1-like endomotifs, while in flies RIDD exhibits little sequence restriction. By comparing nascent and total IRE1α-controlled mRNAs in human breast cancer cells, we discovered not only canonical endomotif-containing RIDD substrates, but also many targets lacking recognizable motifs—degraded by a process we coin RIDDLE, for RIDD lacking endomotif. IRE1α displayed two basic endoribonuclease modalities: endomotif-specific cleavage, minimally requiring dimers; and endomotif-independent promiscuous processing, requiring phospho-oligomers. An oligomer-deficient mutant that did not support RIDDLE failed to rescue cancer-cell viability. These results link IRE1α oligomers, RIDDLE, and cell survival, advancing mechanistic understanding of the UPR.
2021-06-01 | GSE169584 | GEO
Project description:Endoplasmic Reticulum (ER) stress is a hallmark of various diseases, which is dealt with through the activation of an adaptive signaling pathway named the Unfolded Protein Response (UPR). This response is mediated by three ER-resident sensors and the most evolutionary conserved, IRE1α signals through its cytosolic kinase and endoribonuclease (RNase) activities. IRE1α RNase activity can either catalyze the initial step of XBP1 mRNA unconventional splicing or degrade a number of RNAs through Regulated IRE1-Dependent Decay (RIDD). The balance between these two activities plays an instrumental role in cells’ life and death decisions upon ER stress. Until now, the biochemical and biological outputs of IRE1α RNase activity have been well documented, however, the precise mechanisms controlling whether IRE1 signaling is adaptive or pro-death (terminal) remain unclear. This prompted us to further investigate those mechanisms and we hypothesized that XBP1 mRNA splicing and RIDD activity could be co-regulated by the IRE1α RNase regulatory network. We showed that a key nexus in this pathway is the tRNA ligase RtcB which, together with IRE1α, is responsible for XBP1 mRNA splicing. We demonstrated that RtcB is tyrosine phosphorylated by c-Abl and dephosphorylated by PTP1B. Moreover, we identified RtcB Y306 as a key residue which, when phosphorylated, perturbs RtcB interaction with IRE1α, thereby attenuating XBP1 mRNA splicing and favoring RIDD. Our results demonstrate that the IRE1α RNase regulatory network is dynamically fine-tuned by tyrosine kinases and phosphatases upon various stresses and that the nature of the stress determines cell adaptive or death outputs.
2022-02-21 | PXD023433 | Pride
Project description:The molecular connections between homeostatic systems that sustain genome integrity and proteostasis are poorly understood. Here we identified the selective activation of the unfolded protein response transducer IRE1α under genotoxic stress to engage repair programs and sustain cell survival. DNA damage engages IRE1 signaling in the absence of an endoplasmic reticulum (ER) stress signature, leading to the exclusive activation of regulated IRE1α-dependent decay (RIDD) and not its canonical output mediated by the transcription factor XBP1. IRE1α controls the stability of mRNAs involved in the DNA damage response, impacting DNA repair, cell cycle arrest and apoptosis. The protective role of IRE1α under genotoxic stress is conserved in evolution as demonstreated using fly and mouse models. Altogether, our results uncovered a novel intersection between the molecular pathways that ensure genome stability and proteostasis. Affymetrix gene expression data were pre-processed using ‘affyPLM’ packages of the Bioconductor Software. Genes with the strongest evidence of differential expression were obtained using a linear model fit. Data obtained from untreated wild type or IRE1αcKO after ploy I:C treatment liver tissues were used as reference for tunicamycin (Tm) and etoposide (Eto) treatment respectively. Custom chip definition file version 22 from Brainarray based on Entrez ID’s was used. A false positive rate of a=0.05 with FDR correction and a fold change greater 1.5 was taken as the level of significance.
2019-05-10 | GSE130952 | GEO
Project description:IRE1a and XBP1 are key regulators of the unfolded protein response (UPR). XBP1 ablation causes profound hypolipidemia in mice, and triggers feedback activation of its upstream enzyme IRE1a, instigating regulated IRE1-dependent decay (RIDD), an mRNA degradation mechanism dependent on IRE1a's endoribonuclease activity. Comprehensive microarray analysis of XBP1 and/or IRE1a deficient liver identified genes involved in lipogenesis and lipoprotein metabolism as RIDD substrates, which might contribute to the suppression of plasma lipid levels by activated IRE1a. To identify RIDD substrate mRNAs and direct XBP1 targets in the liver, we performed a comprehensive comparative microarray analysis of three groups of RNA samples: WT and XBP1 deficient mice, WT and IRE1a deficient mice untreated or injected with tunicamycin, and XBP1 deficient mice injected with luciferase or IRE1a siRNA.
2012-10-17 | E-GEOD-40515 | biostudies-arrayexpress
Project description:Transcriptional profiling of INS1 cells expressing either WT IRE1α, I642G IRE1α, N906A IRE1α, or spliced XBP1 comparing 1μg/mL dox and 5μM 1NMPP1 treated vs control.
2014-12-22 | GSE17148 | GEO
Project description:IRE1a and XBP1 are key regulators of the unfolded protein response (UPR). XBP1 ablation causes profound hypolipidemia in mice, and triggers feedback activation of its upstream enzyme IRE1a, instigating regulated IRE1-dependent decay (RIDD), an mRNA degradation mechanism dependent on IRE1a's endoribonuclease activity. Comprehensive microarray analysis of XBP1 and/or IRE1a deficient liver identified genes involved in lipogenesis and lipoprotein metabolism as RIDD substrates, which might contribute to the suppression of plasma lipid levels by activated IRE1a.
2012-10-17 | GSE40515 | GEO
Project description:The IRE1α-XBP1 arm of the unfolded protein response (UPR) maintains endoplasmic reticulum (ER) homeostasis, but also controls UPR-independent processes such as cytokine production and lipid metabolism. Yet, the physiological consequences of IRE1α-XBP1 activation in immune cells remain largely unexplored. Here, we report that leukocyte-intrinsic IRE1α-XBP1 signaling drives prostaglandin biosynthesis and pain. Transcriptomic analyses revealed that induction of prostaglandin-endoperoxide synthase 2 (Ptgs2/Cox-2) and prostaglandin E synthase (Ptges/mPGES-1) was compromised in IRE1α-deficient myeloid cells undergoing ER stress or stimulated via pattern recognition receptors. Inducible biosynthesis of prostaglandins, including PGE2, was markedly decreased in myeloid cells lacking IRE1α or XBP1, but not altered in the absence of the two other ER stress sensors PERK and ATF6. Mechanistically, IRE1α-activated XBP1 bound to and directly induced the expression of human PTGS2 and PTGES to enable PGE2 generation. Mice selectively lacking IRE1α-XBP1 in leukocytes, or treated with pharmacological IRE1α inhibitors, failed to induce PGE2 upon challenge with inflammatory stimuli and demonstrated reduced behavioral pain responses in PGE2-dependent models of pain. Our study uncovers an unexpected role for IRE1α-XBP1 as a key mediator of prostaglandin biosynthesis and indicates that targeting this pathway may represent an alternative approach to control pain.
2020-05-16 | GSE131404 | GEO
Project description:IRE1 is an unfolded protein response (UPR) sensor with kinase and endonuclease activity. It plays a central role in the endoplasmic reticulum (ER) stress response through unconventional splicing of XBP1 mRNA and regulated IRE1-dependent decay (RIDD), which cleaves RNA at an XBP1-like consensus sequence (CUGCAG) accompanied by a stem-loop structure. MM cells are known to exhibit an elevated level of baseline ER stress, but RIDD activity has not been well studied in this disease. To investigate novel RIDD targets of possible relevance to the survival/proliferation of MM cells we combined in vitro cleavage assay with RNA sequencing. Bioinformatic analysis revealed hundreds of putative IRE1 substrates, 32 of which were chosen for validation. Looking into the secondary structure of IRE1 substrates, we found that the consensus sequences of IRF4, PRDM1, IKZF1, KLF13, NOTCH1, ATR, DICER, RICTOR, CDK12, FAM168B, and CENPF mRNAs were accompanied by a stem-loop structure essential for IRE1-mediated cleavage. We show that mRNA and protein levels corresponding to these targets were attenuated in an IRE1-dependent manner by treatment with ER-stress-inducing agents. Our results demonstrate for the first time that IRE1 is a key regulator of several proteins of importance in MM survival and proliferation.
2022-04-06 | GSE152070 | GEO