RIP Kinase-Dependent Necrosis Drives Lethal Systemic Inflammatory Response Syndrome

SummaryEngagement of tumor necrosis factor receptor 1 signals two diametrically opposed pathways: survival-inflammation and cell death. An additional switch decides, depending on the cellular context, between caspase-dependent apoptosis and RIP kinase (RIPK)-mediated necrosis, also termed necroptosis. We explored the contribution of both cell death pathways in TNF-induced systemic inflammatory response syndrome (SIRS). Deletion of apoptotic executioner caspases (caspase-3 or -7) or inflammatory caspase-1 had no impact on lethal SIRS. However, deletion of RIPK3 conferred complete protection against lethal SIRS and reduced the amounts of circulating damage-associated molecular patterns. Pretreatment with the RIPK1 kinase inhibitor, necrostatin-1, provided a similar effect. These results suggest that RIPK1-RIPK3-mediated cellular damage by necrosis drives mortality during TNF-induced SIRS. RIPK3 deficiency also protected against cecal ligation and puncture, underscoring the clinical relevance of RIPK kinase inhibition in sepsis and identifying components of the necroptotic pathway that are potential therapeutic targets for treatment of SIRS and sepsis.

Graphical AbstractFigure optionsDownload high-quality image (138 K)Download as PowerPoint slideHighlights
► Necroptosis is a crucial process during lethal SIRS and sepsis
► RIPK3 ablation and RIPK1 inhibition protect mice against TNF-induced lethal SIRS
► Reduced amounts of DAMP release correlate with protection against lethality
► RIPK3 ablation protects against lethal sepsis induced by ceacal ligation and puncture