Engagement of Fas differentially regulates the production of LPS‐induced proinflammatory cytokines and type I interferons

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 proinflammatory 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, costimulation with both LPS and CH11 causes a significant reduction in the level of interferon‐beta (IFNβ) production. This differential effect involves the Fas adaptor FADD because while 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 coimmunoprecipitation experiments demonstrating an interaction between FADD and TRIF. These data identify FADD as a novel component of the noncanonical Toll‐like receptor 4/IFNβ signalling pathway and demonstrate that both Fas and its adaptor FADD can differentially regulate the production of LPS‐induced proinflammatory cytokines and type I interferons.

[1]  H. Wajant,et al.  Cell death‐independent activities of the death receptors CD95, TRAILR1, and TRAILR2 , 2017, The FEBS journal.

[2]  F. Ebner,et al.  Type I Interferons in Bacterial Infections: A Balancing Act , 2016, Front. Immunol..

[3]  E. Brint,et al.  Engagement of Fas on Macrophages Modulates Poly I:C Induced Cytokine Production with Specific Enhancement of IP-10 , 2015, PloS one.

[4]  M. Peter,et al.  The role of CD95 and CD95 ligand in cancer , 2015, Cell Death and Differentiation.

[5]  M. Peter,et al.  The role of CD95 and CD95 ligand in cancer , 2015, Cell Death and Differentiation.

[6]  P. Fallon,et al.  Intestinal Expression of Fas and Fas Ligand Is Upregulated by Bacterial Signaling through TLR4 and TLR5, with Activation of Fas Modulating Intestinal TLR-Mediated Inflammation , 2014, The Journal of Immunology.

[7]  Douglas Golenbock,et al.  The history of Toll-like receptors — redefining innate immunity , 2013, Nature Reviews Immunology.

[8]  E. Brint,et al.  Life in the Fas lane: differential outcomes of Fas signaling , 2013, Cellular and Molecular Life Sciences.

[9]  S. Cullen,et al.  Fas/CD95-induced chemokines can serve as "find-me" signals for apoptotic cells. , 2013, Molecular cell.

[10]  Shizuo Akira,et al.  Dissecting negative regulation of Toll-like receptor signaling. , 2012, Trends in immunology.

[11]  K. Suk,et al.  Stimulation of FasL Induces Production of Proinflammatory Mediators Through Activation of Mitogen-Activated Protein Kinases and Nuclear Factor-κB in THP-1 Cells , 2012, Inflammation.

[12]  P. Krammer,et al.  Regulation of CD95/Fas signaling at the DISC , 2011, Cell Death and Differentiation.

[13]  Adam J. MacNeil,et al.  IFN Regulatory Factor 3 Contributes to the Host Response during Pseudomonas aeruginosa Lung Infection in Mice , 2010, The Journal of Immunology.

[14]  Huan Yang,et al.  Fas (CD95) induces rapid, TLR4/IRAK4-dependent release of pro-inflammatory HMGB1 from macrophages , 2010, Journal of Inflammation.

[15]  B. Williams,et al.  TLR7 Is Involved in Sequence-Specific Sensing of Single-Stranded RNAs in Human Macrophages1 , 2008, The Journal of Immunology.

[16]  S. Akira,et al.  FADD Negatively Regulates Lipopolysaccharide Signaling by Impairing Interleukin-1 Receptor-Associated Kinase 1-MyD88 Interaction , 2007, Molecular and Cellular Biology.

[17]  T. Leanderson,et al.  Type I IFN Signaling Is Crucial for Host Resistance against Different Species of Pathogenic Bacteria1 , 2007, The Journal of Immunology.

[18]  P. Fisher,et al.  Fas-Associated Death Domain-Containing Protein-Mediated Antiviral Innate Immune Signaling Involves the Regulation of Irf71 , 2007, The Journal of Immunology.

[19]  G. Barber,et al.  A FADD-dependent innate immune mechanism in mammalian cells , 2004, Nature.

[20]  S. Ibrahim,et al.  Fas ligation on macrophages enhances IL-1R1–Toll-like receptor 4 signaling and promotes chronic inflammation , 2004, Nature Immunology.

[21]  Masayuki Fukui,et al.  Pathogen-Associated Molecular Patterns Sensitize Macrophages to Fas Ligand-Induced Apoptosis and IL-1β Release1 , 2003, The Journal of Immunology.

[22]  P. Godowski,et al.  Tissue Expression of Human Toll-Like Receptors and Differential Regulation of Toll-Like Receptor mRNAs in Leukocytes in Response to Microbes, Their Products, and Cytokines , 2002, The Journal of Immunology.

[23]  P. Kolattukudy,et al.  Protection against lipopolysaccharide-induced myocardial dysfunction in mice by cardiac-specific expression of soluble Fas. , 2008, Journal of molecular and cellular cardiology.

[24]  M. Umemura,et al.  Pathogen-Associated Molecular Patterns Sensitize Macrophages to Fas Ligand-Induced Apoptosis and IL-1 Release , 2003 .

[25]  J. Harlan,et al.  The Fas-associated death domain protein suppresses activation of NF-kappa B by LPS and IL-1 beta. , 2002, The Journal of clinical investigation.