TRIF and IRF-3 binding to the TNF promoter results in macrophage TNF dysregulation and steatosis induced by chronic ethanol

XJ Zhao, Q Dong, J Bindas, JD Piganelli… - The Journal of …, 2008 - journals.aai.org
XJ Zhao, Q Dong, J Bindas, JD Piganelli, A Magill, J Reiser, JK Kolls
The Journal of Immunology, 2008journals.aai.org
Chronic ethanol (EtOH) abuse results in the development of steatosis, alcoholic hepatitis,
and cirrhosis. Augmented TNF-α production by macrophages and Kupffer cells and
signaling via the p55 TNF receptor have been shown to be critical for these effects of chronic
EtOH; however, the molecular mechanisms leading to augmented TNF-α production remain
unclear. Using cell culture models and in vivo studies we demonstrate that chronic EtOH
results in increased TNF-α transcription, which is independent of NF-κB. Using reporter …
Abstract
Chronic ethanol (EtOH) abuse results in the development of steatosis, alcoholic hepatitis, and cirrhosis. Augmented TNF-α production by macrophages and Kupffer cells and signaling via the p55 TNF receptor have been shown to be critical for these effects of chronic EtOH; however, the molecular mechanisms leading to augmented TNF-α production remain unclear. Using cell culture models and in vivo studies we demonstrate that chronic EtOH results in increased TNF-α transcription, which is independent of NF-κB. Using reporter assays and chromatin immunoprecipitation we found that this increased transcription is due to increased IRF-3 binding to and transactivation of the TNF promoter. As IRF-3 is downstream from the TLR4 adaptor TIR-domain-containing adapter-inducing IFN-β (Trif), we demonstrate that macrophages from Trif−/− mice are resistant to this dysregulation of TNF-α transcription by EtOH in vitro as well as EtOH-induced steatosis and TNF dysregulation in vivo. These data demonstrate that the Trif/IRF-3 pathway is a target to ameliorate liver dysfunction associated with chronic EtOH.
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