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    TLR3‐mediated IFN‐β gene induction is negatively regulated by the TLR adaptor MyD88 adaptor‐like


    Siednienko, Jakub and Halle, Annett and Kamalpreet, Nagpal and Golenbock, Douglas and Miggin, Sinead (2010) TLR3‐mediated IFN‐β gene induction is negatively regulated by the TLR adaptor MyD88 adaptor‐like. European Journal of Immunology, 40 (11). ISSN 1521-4141

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    Abstract

    There is limited insight into the mechanisms involved in the counterregulation of TLR. Given the important role of TLR3/TIR domain‐containing adaptor‐inducing IFN‐β (TRIF)‐dependent signalling in innate immunity, novel insights into its modulation is of significance in the context of many physiological and pathological processes. Herein, we sought to perform analysis to definitively assign a mechanistic role for MyD88 adaptor‐like (Mal), an activator of TLR2/4 signalling, in the negative regulation of TLR3/TRIF signalling. Biochemical and functional analysis demonstrates that Mal negatively regulates TLR3, but not TLR4, mediated IFN‐β production. Co‐immunoprecipitation experiments demonstrate that Mal associates with IRF7 (IRF, IFN regulatory factor), not IRF3, and Mal specifically blocks IRF7 activation. In doing so, Mal impedes TLR3 ligand‐induced IFN‐β induction. Interestingly, Mal does not affect the induction of IL‐6 and TNF‐α upon TLR3 ligand engagement. Together, these data show that the TLR adaptor Mal interacts with IRF7 and, in doing so, impairs IFN‐β induction through the positive regulatory domains I‐III enhancer element of the IFN‐β gene following poly(I:C) stimulation. Our findings offer a new mechanistic insight into TLR3/TRIF signalling through a hitherto unknown mechanism whereby Mal inhibits poly(I:C)‐induced IRF7 activation and concomitant IFN‐β production. Thus, Mal is essential in restricting TLR3 signalling thereby protecting the host from unwanted immunopathologies associated with excessive IFN‐β production.

    Item Type: Article
    Keywords: IFN‐β; IFN regulatory factor 7; MyD88 adaptor-like; TLR3;
    Academic Unit: Faculty of Science and Engineering > Biology
    Item ID: 12610
    Identification Number: https://doi.org/10.1002/eji.201040547
    Depositing User: Sinead Miggin
    Date Deposited: 25 Mar 2020 12:06
    Journal or Publication Title: European Journal of Immunology
    Publisher: Wiley-VCH Verlag
    Refereed: Yes
    URI:

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