Absence of Mal/TIRAP Results in Abrogated Imidazoquinolinones-Dependent Activation of IRF7 and Suppressed IFNß and IFN-I Activated Gene Production.
Int J Mol Sci
; 21(23)2020 Nov 25.
Article
in English
| MEDLINE | ID: covidwho-951247
ABSTRACT
Activation of TLR7 by small imidazoquinoline molecules such as R848 or R837 initiates signaling cascades leading to the activation of transcription factors, such as AP-1, NF-κB, and interferon regulatory factors (IRFs) and afterward to the induction of cytokines and anti-viral Type I IFNs. In general, TLRs mediate these effects by utilizing different intracellular signaling molecules, one of them is Mal. Mal is a protein closely related to the antibacterial response, and its role in the TLR7 pathways remains poorly understood. In this study, we show that Mal determines the expression and secretion of IFNß following activation of TLR7, a receptor that recognizes ssRNA and imidazoquinolines. Moreover, we observed that R848 induces Mal-dependent IFNß production via ERK1/2 activation as well as the transcription factor IRF7 activation. Although activation of TLR7 leads to NF-κB-dependent expression of IRF7, this process is independent of Mal. We also demonstrate that secretion of IFNß regulated by TLR7 and Mal in macrophages and dendritic cells leads to the IP-10 chemokine expression. In conclusion, our data demonstrate that Mal is a critical regulator of the imidazoquinolinones-dependent IFNß production via ERK1/2/IRF7 signaling cascade which brings us closer to understanding the molecular mechanism's regulation of innate immune response.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Membrane Glycoproteins
/
Interferon-beta
/
Interferon Regulatory Factor-7
/
Toll-Like Receptor 7
/
Myelin and Lymphocyte-Associated Proteolipid Proteins
Limits:
Animals
/
Humans
Language:
English
Year:
2020
Document Type:
Article
Affiliation country:
Ijms21238925
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