Raver1 links Ripk1 RNA splicing to caspase-8-mediated pyroptotic cell death, inflammation, and pathogen resistance
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ABSTRACT:
PROVIDER: PRJNA1182361 | ENA |
REPOSITORIES: ENA
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Project description:Multiple cell death and inflammatory signaling pathways converge on two critical factors: receptor interacting serine/threonine kinase 1 (RIPK1) and caspase-8. Careful regulation of these molecules is critical to control apoptosis, pyroptosis and inflammation. Here we discovered a pivotal role of Raver1 as an essential regulator of Ripk1 pre-mRNA splicing, expression, and functionality, and the subsequent caspase-8-dependent inflammatory cell death. Macrophages from Raver1-deficient mice exhibit altered splicing of Ripk1, accompanied by diminished cell death and reduced activation of caspase-8, Gasdermin D and E, caspase-1, as well as decreased interleukin-18 (IL-18) and IL-1ß production. These effects were triggered by Yersinia bacteria, or by restraining TAK1 or IKKβ in the presence of LPS, TNF family members, or IFNγ. Consequently, animals lacking Raver1 showed heightened susceptibility to Yersinia infection. Raver1 and RIPK1 also controlled the expression and function of the C-type lectin receptor Mincle. Our study underscores the critical regulatory role of Raver1 in modulating innate immune responses and highlights its significance in directing in vivo and in vitro inflammatory processes.
2025-03-05 | GSE281137 | GEO
Project description:Type-I interferons (IFNs) are an essential component of the innate immune response that are upregulated in response to infection. However, a low level of basal, or tonic, IFN expression is also critical to maintain tissue homeostasis. While the regulation of type-I IFN production during infection is well studied, the mechanisms controlling this basal expression and its impacts on homeostasis remain enigmatic. Here, we report the role of caspase-8 as a negative regulator of type-I IFN production during homeostasis in vitro and in vivo. Caspase-8 deficiency led to hyperactivation of basal type-I IFN signaling across multiple cell types and tissues and provided naturally heightened resistance to viral infection with norovirus. Mechanistically, the absence of caspase-8 allowed for an interaction between RIPK1 and TBK1, leading to enhanced TBK1 activation and aberrant type-I IFN production under homeostatic conditions. Loss of RIPK1 in caspase-8–deficient cells normalized TBK1 phosphorylation, IFN production and IFN signaling, thereby sensitizing cells to viral infection-induced inflammasome activation and inflammatory cell death, PANoptosis. In vivo, the elevated type-I IFN signaling, as well as the previously established early onset lymphadenopathy at 8 weeks of age, in caspase-8–deficient mice were reduced upon deletion of RIPK1 or type-I IFN neutralization. Overall, our study identified a mechanism which constrains tonic type-I IFN production and signaling during homeostasis. These results advance our understanding of tissue homeostasis and IFN regulation in infectious, autoimmune and autoinflammatory diseases, providing new insights for the development of disease treatments.
2022-11-16 | GSE211623 | GEO
Project description:The pediatric immune deficiency X-linked proliferative disease-2 (XLP-2) is a unique disease, with patients presenting with either hemophagocytic lymphohistiocytosis (HLH) or intestinal bowel disease (IBD). Interestingly, XLP-2 patients display high levels of IL-18 in the serum even while in stable condition, presumably through spontaneous inflammasome activation. Recent data suggests that LPS stimulation can trigger inflammasome activation through a TNFR2/TNF/TNFR1 mediated loop in xiap−/− macrophages. Yet, the direct role TNFR2-specific activation plays in the absence of XIAP is unknown. We found TNFR2-specific activation leads to cell death in xiap−/− myeloid cells, particularly in the absence of the RING domain. RIPK1 kinase activity downstream of TNFR2 resulted in a TNF/TNFR1 cell death, independent of necroptosis. TNFR2-specific activation leads to a similar inflammatory NF-kB driven transcriptional profile as TNFR1 activation with the exception of upregulation of NLRP3 and caspase-11. Activation and upregulation of the canonical inflammasome upon loss of XIAP was mediated by RIPK1 kinase activity and ROS production. While both the inhibition of RIPK1 kinase activity and ROS production reduced cell death, as well as release of IL-1β, the release of IL-18 was not reduced to basal levels. This study supports targeting TNFR2 specifically to reduce IL-18 release in XLP-2 patients and to reduce priming of the inflammasome components.
2021-03-01 | E-MTAB-10103 | biostudies-arrayexpress
Project description:Ptpn6 is a cytoplasmic phosphatase that functions to prevent autoimmune disease and IL-1R-dependent caspase-1-independent inflammatory disease. Conditional deletion of Ptpn6 in neutrophils (Ptpn6∆PMN) is sufficient to initiate IL-1R-dependent cutaneous inflammatory disease, but the source of IL-1 and the mechanisms behind IL-1 release remain unclear. Here, we investigated the mechanisms controlling IL-1α/β release from neutrophils by inhibiting caspase-8-dependent apoptosis and Ripk1/Ripk3/Mlkl-regulated necroptosis. Loss of Ripk1 accelerated disease onset, whereas combined deletion of caspase-8 and either Ripk3 or Mlkl strongly protected Ptpn6∆PMN mice. Ptpn6∆PMN neutrophils displayed increased p38-dependent Ripk1-independent IL-1 and TNF production, and were prone to cell death. Together, these data emphasize dual functions for Ptpn6 in the negative regulation of p38 MAP kinase activation to control TNF and IL-1α/β transcription, and in maintaining Ripk1 function to prevent caspase-8- and Ripk3/Mlkl-dependent cell death and concomitant IL-1α/β release.
2019-11-12 | GSE139223 | GEO
Project description:Dysfunctional NF-kB signaling is critically involved in Inflammatory bowel disease (IBD). We investigated the mechanism by which RIPK1 and TRADD, two key mediators of NF-kB signaling, in mediating intestinal pathology using TAK1 IEC deficient model. We show that phosphorylation of TRADD by TAK1 modulates RIPK1-dependent apoptosis. TRADD and RIPK1 act cooperatively to mediate cell death mediated by TNF and TLR signaling. We demonstrate the pathological evolution from RIPK1-dependent ileitis to RIPK1- and TRADD-co-dependent colitis in TAK1 IEC deficient condition. Combined RIPK1 inhibition and TRADD knockout completely protect against intestinal pathology and lethality in TAK1 IEC KO mice. Furthermore, we identify distinctive microbiota dysbiosis biomarkers for RIPK1-dependent ileitis and TRADD-dependent colitis. These findings reveal the cooperation between RIPK1 and TRADD in mediating cell death and inflammation in IBD with NF-kB deficiency and suggest the possibility of combined RIPK1 kinase inhibition and TRADD knockout as a new therapeutic strategy for IBD.
2025-01-22 | GSE279034 | GEO
Project description:Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a cytosolic protein kinase that regulates multiple inflammatory and cell death pathways. Serine/Threonine phosphorylation of RIPK1 is known to suppress RIPK1 kinase-mediated cell death in the contexts of inflammation, infection and embryogenesis, however, regulation by tyrosine phosphorylation has not been reported. Here, we show that non-receptor tyrosine kinases Janus kinase 1 (JAK1) and SRC are able to phosphorylate RIPK1 at Y384 (Y383 in murine RIPK1), leading to suppression of TNF-induced cell death. Mice bearing a homozygous Ripk1 mutation that prevents tyrosine phosphorylation of RIPK1 (Ripk1Y383F/Y383F), develop systemic inflammation and emergency haematopoiesis. Mechanistically, Ripk1Y383F/Y383F mutation promotes RIPK1 kinase activation and enhances TNF-induced apoptosis and necroptosis, which is partially due to impaired recruitment and activation of MAP kinase-activated protein kinase 2 (MK2). The systemic inflammation and emergency haematopoiesis in Ripk1Y383F/Y383F mice are largely alleviated by RIPK1 kinase inhibition, and prevented by genomic deletions targeted to the upstream pathway (either to Tumor necrosis factor receptor 1 or RIPK3 and Caspase8 simultaneously). In summary, our results demonstrate that tyrosine phosphorylation of RIPK1 is critical for regulating RIPK1 activity to limit cell death and inflammation.
2022-10-12 | PXD036995 | Pride
Project description:The execution of shock following high dose E. coli lipopolysaccharide (LPS) or bacterial sepsis in mice required pro-apoptotic caspase-8 in addition to pro-pyroptotic caspase-11 and gasdermin d. Hematopoietic cells produced MyD88- and TRIF-dependent inflammatory cytokines sufficient to initiate LPS shock independent of caspase-8 or caspase-11. Both proteases had to be present to support tissue injury, dependent upon TNF and interferon , first observed in the small intestine and later in spleen and thymus. Caspase-11 enhanced the activation of caspase-8 and extrinsic cell death machinery within the lower small intestine. Neither caspase-8 nor caspase-11 was individually sufficient for shock, but collaborated to amplify the inflammatory signals associated with tissue injury. Therefore, combined pyroptotic and apoptotic signaling mediated endotoxemia independent of RIPK1 kinase activity and RIPK3 function. These observations bring to light the relevance of tissue compartmentalization during inflammatory signaling in vivo where cytokines execute diverse cell death pathways and tissue damage.
2018-08-07 | GSE115094 | GEO
Project description:Dysfunctional NF-kB signaling is critically involved in Inflammatory bowel disease (IBD). We investigated the mechanism by which RIPK1 and TRADD, two key mediators of NF-kB signaling, in mediating intestinal pathology using TAK1 IEC deficient model. We show that phosphorylation of TRADD by TAK1 modulates RIPK1-dependent apoptosis. TRADD and RIPK1 act cooperatively to mediate cell death mediated by TNF and TLR signaling. We demonstrate the pathological evolution from RIPK1-dependent ileitis to RIPK1- and TRADD-co-dependent colitis in TAK1 IEC deficient condition. Combined RIPK1 inhibition and TRADD knockout completely protect against intestinal pathology and lethality in TAK1 IEC KO mice. Furthermore, we identify distinctive microbiota dysbiosis biomarkers for RIPK1-dependent ileitis and TRADD-dependent colitis. These findings reveal the cooperation between RIPK1 and TRADD in mediating cell death and inflammation in IBD with NF-kB deficiency and suggest the possibility of combined RIPK1 kinase inhibition and TRADD knockout as a new therapeutic strategy for IBD.
2025-01-22 | GSE279700 | GEO
Project description:Dysfunctional NF-kB signaling is critically involved in Inflammatory bowel disease (IBD). We investigated the mechanism by which RIPK1 and TRADD, two key mediators of NF-kB signaling, in mediating intestinal pathology using TAK1 IEC deficient model. We show that phosphorylation of TRADD by TAK1 modulates RIPK1-dependent apoptosis. TRADD and RIPK1 act cooperatively to mediate cell death mediated by TNF and TLR signaling. We demonstrate the pathological evolution from RIPK1-dependent ileitis to RIPK1- and TRADD-co-dependent colitis in TAK1 IEC deficient condition. Combined RIPK1 inhibition and TRADD knockout completely protect against intestinal pathology and lethality in TAK1 IEC KO mice. Furthermore, we identify distinctive microbiota dysbiosis biomarkers for RIPK1-dependent ileitis and TRADD-dependent colitis. These findings reveal the cooperation between RIPK1 and TRADD in mediating cell death and inflammation in IBD with NF-kB deficiency and suggest the possibility of combined RIPK1 kinase inhibition and TRADD knockout as a new therapeutic strategy for IBD.
2025-01-22 | GSE279702 | GEO
Project description:RIPK1 plays an important role initiating inflammatory signaling downstream of TLR4 and TNFR1, acting as a polyubiquitinated scaffold for the recruitment and activation of NFkB and MAPK signaling. We geneerated a murine model inhibitng the autophosphorylation of threonine 169 (T169) on murine Ripk1 to determine the effect on cell death complex formation and caspase activation. Due to the dual role of RIPK1 in inflammatiton and cell death we first sought to confirm that tthis mutation did not disturb the scaffolding functions of RIPK1 and did not alter tthe inflammatory response after stimulation of TLR4.
2024-08-15 | GSE263905 | GEO