Engagement of Fas differentially regulates the production of LPS-induced pro-inflammatory cytokines and type I Interferons.

Engagement of Fas differentially regulates the production of LPS-induced pro-inflammatory cytokines and type I Interferons.

FEBS J. 2018 Dec 11;:

Authors: Brennan K, Lyons C, Fernandes P, Doyle S, Houston A, Brint E

Abstract
Fas (CD95) signalling is best known for its role in apoptosis, however, recent reports have shown it to be involved in other cellular responses as well, including inflammation. Fas and its adaptor protein FADD are known to negatively regulate LPS-induced pro-inflammatory responses, but their role in LPS-induced type I Interferon production is unknown. Here, we demonstrate that Fas engagement on macrophages, using an agonistic Fas antibody CH11, augments LPS-induced NF-κB responses, causing increased production of TNFα, IL-8, IL-6 and IL-12. Conversely, co-stimulation with both LPS and CH11 causes a significant reduction in the level of IFNβ production. This differential effect involves the Fas adaptor FADD because whilst LPS-induced IL-6 production increased in FADD-/-  murine embryonic fibroblasts, LPS-induced IFNβ production was significantly reduced in these cells. Overexpression of a dominant negative form of FADD (FADD-DD) inhibits LPS-induced IFNβ-luciferase but not LPS-induced NF-κB-luciferase. In contrast, overexpression of full-length FADD inhibited LPS-induced NF-κB-luciferase activation but was seen to augment LPS-induced IFNβ-luciferase. Moreover, FADD-DD inhibits TRIF, TRAM, IKKε, TBK-1 and TRAF3 induced IFNβ-luciferase production, with co-immunoprecipitation experiments demonstrating an interaction between FADD and TRIF. These data identify FADD as a novel component of the non-canonical TLR4/IFNβ signalling pathway and demonstrate that both Fas and its adaptor FADD can differentially regulate the production of LPS-induced pro-inflammatory cytokines and type I Interferons. This article is protected by copyright. All rights reserved.

PMID: 30536547 [PubMed - as supplied by publisher]

from PubMed via alexandrossfakianakis on Inoreader https://ift.tt/2rzrMrg