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

Abstract

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-induced death of primary IECs. Collectively, we demonstrate that TNF-α synergises with IFN-γ to kill IECs via the CASP8-JAK1/2-STAT1 module independently of canonical TNFR1 and cell death signalling. This non-canonical cell death pathway may underpin immunopathology driven by IFN-γ/TNF-α in diverse autoinflammatory diseases such as IBD, and its inhibition may contribute to the therapeutic efficacy of anti-TNFs and JAKinibs.

A Novel Necroptosis-Related lncRNA Signature Predicts the Prognosis of Lung Adenocarcinoma

“…IFN-activated JAK/STAT signaling induced the robust expression of ZBP1, which complexed with RIPK3 to trigger MLKL-driven necroptosis ( Ingram et al, 2019 ). Similarly, TNF-α synergized with IFN-γ could induce epithelial cell necroptosis through the CASP8-JAK1/2-STAT1 module ( Woznicki et al, 2021 ). Taken together, we speculated that necroptosis probably contributed to the occurrence and development of LUAD through the JAK/STAT signaling pathway.…”

Reduced Incidence of Necrotizing Enterocolitis due to the Anti-Inflammatory Effects of CXCL14 in Intestinal Tissue

“…Research confirmed that the proinflammatory response is one of the mechanisms of intestinal epithelial injury [ 7 ]. Furthermore, as the classical proinflammatory cytokines, TNF- α and INF- γ could directly lead to intestinal epithelial damage [ 8 ]. The release of the proinflammatory cytokines in the intestinal tract is mainly regulated through the TLR4 pathway [ 9 , 10 ], which could be activated by bacteria and its related product lipopolysaccharide (LPS) [ 6 , 11 ].…”

Investigating the Role of the NLRP3 Inflammasome Pathway in Acute Intestinal Inflammation: Use of THP-1 Knockout Cell Lines in an Advanced Triple Culture Model

“…Our results show an enhanced susceptibility of goblet-like HT29-MTX-E12 cells towards inflammation-mediated cytotoxicity, compared to enterocyte-like Caco-2 cells. Strong synergistic cytotoxicity of TNF-a and IFN-g towards HT29 cells has been described previously (46,47). For our investigations, a high dose of IFN-g is used to initially activate the THP-1 cells, so it is unlikely that the concentration of this cytokine differs significantly between the three inflamed cultures.…”