TNF-α synergises with IFN-γ to induce caspase-8-JAK1/2-STAT1-dependent death of intestinal epithelial cells

作者：Jerzy A. Woznicki, Nisha Saini, Peter F. Flood, Subhasree Rajaram, Ciaran M. Lee, Panagiota Stamou, Agnieszka Skowyra, Milán Bustamante-Garrido, Karine Regazzoni, Nyree Crawford, Simon S. McDade, Daniel B. Longley, Pedro Aza‐Blanc, Fergus Shanahan, Syed A. Zulquernain, Jane McCarthy, Silvia Melgar, Bradford L. McRae, Kenneth Nally · 发表于：Cell Death and Disease · 年份：2021 · DOI：10.1038/s41419-021-04151-3 · 被引用次数：185 · 研究领域：IL-33, ST2, and ILC Pathways、Immune responses and vaccinations、Cytokine Signaling Pathways and Interactions

Rewiring of host cytokine networks is a key feature of inflammatory bowel diseases (IBD) such as Crohn's disease (CD). Th1-type cytokines-IFN-γ and TNF-α-occupy critical nodes within these networks and both are associated with disruption of gut epithelial barrier function. This may be due to their ability to synergistically trigger the death of intestinal epithelial cells (IECs) via largely unknown mechanisms. In this study, through unbiased kinome RNAi and drug repurposing screens we identified JAK1/2 kinases as the principal and nonredundant drivers of the synergistic killing of human IECs by IFN-γ/TNF-α. Sensitivity to IFN-γ/TNF-α-mediated synergistic IEC death was retained in primary patient-derived intestinal organoids. Dependence on JAK1/2 was confirmed using genetic loss-of-function studies and JAK inhibitors (JAKinibs). Despite the presence of biochemical features consistent with canonical TNFR1-mediated apoptosis and necroptosis, IFN-γ/TNF-α-induced IEC death was independent of RIPK1/3, ZBP1, MLKL or caspase activity. Instead, it involved sustained activation of JAK1/2-STAT1 signalling, which required a nonenzymatic scaffold function of caspase-8 (CASP8). Further modelling in gut mucosal biopsies revealed an intercorrelated induction of the lethal CASP8-JAK1/2-STAT1 module during ex vivo stimulation of T cells. Functional studies in CD-derived organoids using inhibitors of apoptosis, necroptosis and JAKinibs confirmed the causative role of JAK1/2-STAT1 in cytokine-in...