Novel Bioinformatics Method for Identification of Genome-Wide Non-Canonical Spliced Regions using RNA-Seq Data
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE54631 | GEO | 2014/07/29
SECONDARY ACCESSION(S): PRJNA237229
REPOSITORIES: GEO
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Project description:We developed a bioinformatics approach called the Read-Split-Walk (RSW) pipeline, and evaluated it using two Ire1? heterozygous and two Ire1?-null samples. The 26nt non-canonical splice site in Xbp1 was detected as the top hit by our RSW pipeline in heterozygous samples but not in the negative control Ire1? knockout samples. We compared the Xbp1 results from our approach with results using the alignment program BWA, STAR, Exonerate and the Unix “grep” command. We then applied our RSW pipeline to RNA-Seq data from the SKBR3 human breast cancer cell line. RSW reported a large number of non-canonical spliced regions for 108 genes in chromosome 17, which were identified by an independent study. Identification of non-canonical spliced regions for mouse MEF samples (two Ire1? heterozygous and two Ire1?-null samples)
2014-07-29 | E-GEOD-54631 | biostudies-arrayexpress
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:Signaling cascades during adipogenesis culminate in the expression of two essential adipogenic factors, PPARγ and C/EBPα. Here we demonstrate that the IRE1α-XBP1 pathway, the most conserved branch of the unfolded protein response (UPR), is indispensable for adipogenesis. Indeed, XBP1-deficient mouse embryonic fibroblasts and 3T3-L1 cells with XBP1 or IRE1α knockdown exhibit profound defects in adipogenesis. Intriguingly, C/EBPβ, a key early adipogenic factor, induces Xbp1 expression by directly binding to its proximal promoter region. Subsequently, XBP1 binds to the promoter of Cebpa and activates its gene expression. The posttranscriptional splicing of Xbp1 mRNA by IRE1α is required as only the spliced form of XBP1 (XBP1s) rescues the adipogenic defect exhibited by XBP1-deficient cells. Taken together, our data show that the IRE1α-XBP1 pathway plays a key role in adipocyte differentiation by acting as a critical regulator of the morphological and functional transformations during adipogenesis.
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Project description:Cancer cells exploit adaptive responses such as endoplasmic reticulum (ER) stress to support their survival. ER stress response is mediated in part by the ER-localized transmembrane sensor IRE1α endoribonuclease and its substrate XBP1 to regulate XBP1 target gene expression. However, the mechanism that controls the IRE1α/XBP1 pathway remains poorly understood. CARM1 is an oncogene that is often overexpressed in a number of cancer types including ovarian cancer. Here we report that CARM1 determines ER stress response by controlling the IRE1α/XBP1 pathway. Genome-wide profiling revealed that CARM1 regulates XBP1 target gene expression during ER stress response. CARM1 directly interacts with XBP1. Inhibition of the IRE1α/XBP1 pathway was effective in ovarian cancer in a CARM1-dependent manner both in vitro and in vivo in orthotopic and patient-derived xenograft models. In addition, IRE1α inhibitor B-I09 synergizes with immune checkpoint blockade anti-PD1 antibody in an immunocompetent CARM1-expressing ovarian cancer model.
2021-08-11 | GSE157117 | GEO
Project description:Cancer cells exploit adaptive responses such as endoplasmic reticulum (ER) stress to support their survival. ER stress response is mediated in part by the ER-localized transmembrane sensor IRE1α endoribonuclease and its substrate XBP1 to regulate XBP1 target gene expression. However, the mechanism that controls the IRE1α/XBP1 pathway remains poorly understood. CARM1 is an oncogene that is often overexpressed in a number of cancer types including ovarian cancer. Here we report that CARM1 determines ER stress response by controlling the IRE1α/XBP1 pathway. Genome-wide profiling revealed that CARM1 regulates XBP1 target gene expression during ER stress response. CARM1 directly interacts with XBP1. Inhibition of the IRE1α/XBP1 pathway was effective in ovarian cancer in a CARM1-dependent manner both in vitro and in vivo in orthotopic and patient-derived xenograft models. In addition, IRE1α inhibitor B-I09 synergizes with immune checkpoint blockade anti-PD1 antibody in an immunocompetent CARM1-expressing ovarian cancer model.
2021-08-11 | GSE157116 | GEO
Project description:Group 3 innate lymphoid cells (ILC3s) are key players in intestinal homeostasis. Endoplasmic reticulum (ER) stress is linked to inflammatory bowel disease (IBD). Herein, we used cell culture, novel mouse models, and human specimens to examine if ER stress in ILC3s impacts IBD pathophysiology. We show that mouse intestinal ILC3s exhibited a 24h-rhythmic expression pattern of the master ER stress response regulator, IRE1α-XBP1. Proinflammatory cytokine IL-23 selectively stimulated IRE1α-XBP1 in mouse ILC3s through mitochondrial reactive oxygen species (mtROS). IRE1α-XBP1 was activated in ILC3s of mice exposed to experimental colitis and in inflamed human IBD specimens. Mice with Ire1α deletion in ILC3s (Ire1αΔRorc) showed reduced expression of ER stress response and cytokine genes including Il22 in ILC3s and were highly vulnerable to infections and colitis. Administration of IL-22 counteracted their colitis susceptibility. In human ILC3s, IRE1 inhibitors suppressed cytokine production, which was upregulated by an IRE1 activator. Moreover, the frequencies of intestinal XBP1s+ ILC3s in Crohn’s disease patients before administration of ustekinumab, an anti-IL-12/IL-23 antibody, positively correlated with response to treatment. We demonstrate that a non-canonical mtROS-IRE1α-XBP1 pathway augments cytokine production by ILC3s and identify XBP1+ ILC3s as a potential biomarker for predicting response to anti-IL-23 therapies in IBD. Group 3 innate lymphoid cells (ILC3s) have recently emerged as important regulators and potential drug targets for IBD. However, the response of ILC3s to environmental stimuli during intestinal inflammation remains elusive. IRE1a-XBP1 serves as the regulatory hub of the unfolded protein response (UPR) that plays a vital role in intestinal inflammation.
2024-05-31 | GSE261091 | 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: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:Natural killer (NK) cells are critical mediators of host immunity against infectious disease and cancer. The intrinsic regulators of NK cells are not fully understood. Here, we demonstrate that the ER stress sensor inositol-requiring enzyme 1 (IRE1α) and its substrate transcription factor X-box-binding protein 1 (XBP1) critically drive NK cell-mediated responses against viral infection and tumors. IRE1α and XBP1 were essential for the robust expansion of activated mouse and human NK cells. Transcriptome analysis revealed the transcription factor c-Myc as a novel and direct target of XBP1 for downstream regulation of NK cell proliferation. Genetic ablation or pharmaceutical blockade of IRE1α downregulated c-Myc, whereas overexpression of XBP1 resulted in c-Myc hyperactivation. NK cells lacking c-Myc demonstrated a functional deficit comparable to IRE1α or XBP1 deficiency. Overall, our study identifies a novel IRE1-XBP1-cMyc axis in NK cell immunity, providing new insight into the host immune response against infection and cancer.
2019-04-01 | GSE113214 | GEO
Project description:Background/Aims: Cholestatic liver diseases (CLD) are the leading indication for pediatric liver transplantation. Increased intrahepatic bile acid concentrations cause endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) is activated to maintain homeostasis. UPR dysregulation, including the inositol-requiring enzyme 1α/X-box protein 1 (IRE1α/XBP1) pathway, is associated with several adult liver diseases. We evaluated hepatic UPR expression in pediatric patients with end-stage CLD and hypothesize that an inability to appropriately activate the hepatic IRE1α/XBP1 pathway is associated with the pathogenesis of CLD. Methods: We evaluated 34 human liver explants. Cohorts included: pediatric CLD (Alagille, ALGS, and progressive familial intrahepatic cholestasis, PFIC), pediatric non-cholestatic liver disease controls (autoimmune hepatitis, AIH), adult CLD, and normal controls. We performed RNA-seq, quantitative PCR, and western blotting to measure expression differences of the hepatic UPR and other signaling pathways. Results: Metascape pathway analysis demonstrated that the KEGG ‘protein processing in ER’ pathway was downregulated in pediatric CLD compared to normal controls. Pediatric CLD had decreased hepatic IRE1α/XBP1 pathway gene expression and decreased protein expression of p-IRE1α compared to normal controls. These CLD changes were not disease-specific to ALGS or PFIC. IRE1α/XBP1 pathway gene expression was decreased in pediatric CLD compared to AIH disease controls. Conclusion: Pediatric CLD explants have decreased gene and protein expression of the protective IRE1α/XBP1 pathway and down-regulated KEGG protein processing in the ER pathways. IRE1α/XBP1 pathway expression differences occur when compared to both normal and non-cholestatic disease controls. Attenuated expression of the IRE1α/XBP1 pathway is associated with cholestatic diseases and could be targeted to treat pediatric CLD.
2022-06-23 | GSE206364 | GEO