Constitutive Interferon Attenuates RIPK1/3-Mediated Cytokine Translation

Abstract

Summary: Receptor-interacting protein kinase 1 (RIPK1) and 3 (RIPK3) are well known for their capacity to drive necroptosis via mixed-lineage kinase-like domain (MLKL). Recently, RIPK1/3 kinase activity has been shown to drive inflammation via activation of MAPK signaling. However, the regulatory mechanisms underlying this kinase-dependent cytokine production remain poorly understood. In the present study, we establish that the kinase activity of RIPK1/3 regulates cytokine translation in mouse and human macrophages. Furthermore, we show that this inflammatory response is downregulated by type I interferon (IFN) signaling, independent of type I IFN-promoted cell death. Specifically, low-level constitutive IFN signaling attenuates RIPK-driven activation of cap-dependent translation initiation pathway components AKT, mTORC1, 4E-BP and eIF4E, while promoting RIPK-dependent cell death. Altogether, these data characterize constitutive IFN signaling as a regulator of RIPK-dependent inflammation and establish cap-dependent translation as a crucial checkpoint in the regulation of cytokine production. : Balancing inflammatory responses is critical for host survival. Muendlein et al. show that constitutive type I IFN signaling inhibits translation machinery activated downstream of the kinase activity of RIPK1/3, preventing the production of a subset of inflammatory cytokines. This work identifies cap-dependent translation as a checkpoint in regulation of RIPK1/3-kinase-dependent inflammation. Keywords: inflammation, necroptosis, constitutive IFN, translation, macrophage, receptor-interacting protein kinases