1. Myocardin-related transcription factor A (MRTF-A) plays an essential role in hepatic stellate cell activation by epigenetically modulating TGF-β signaling.
- Author
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Tian, Wenfang, Fan, Zhiwen, Li, Jianfei, Hao, Chenzhi, Li, Min, Xu, Huihui, Wu, Xiaoyan, Zhou, Bisheng, Zhang, Liping, Fang, Mingming, and Xu, Yong
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MYOCARDIN , *TRANSCRIPTION factors , *EPIGENETICS , *TRANSFORMING growth factors , *CELLULAR signal transduction , *FIBROSIS , *LIVER cells - Abstract
Fibrosis following injury is a common adaptive response in the liver, which can lead to irreparable and life-threatening cirrhosis and hepatocellular carcinoma without effectual intervention. The molecular mechanisms underlying fibrogenic response in the liver remains poorly understood. Here we report that mice with deficiency in myocardin-related transcription factor A (MRTF-A) showed resistance to thioacetamide (TAA)-induced liver fibrosis with significantly reduced expression of pro-fibrogenic genes when compared to wild type littermates. Over-expression of MRTF-A enhanced whereas depletion of MRTF-A alleviated pro-fibrogenic transcription induced by TGF-β, a major pro-fibrogenic factor in hepatic stellate cells (HSCs). Mechanistically, MRTF-A silencing in HSCs impacted the chromatin structure by reducing the deposition of methylated histone H3K4 on the promoters of pro-fibrogenic genes. Further analyses revealed that MRTF-A interacted with and recruited several key epigenetic factors involved in H3K4 methylation, including ASH2, WDR5, and SET1, to the promoters of pro-fibrogenic genes in response to TGF-β treatment. Over-expression of ASH2, WDR5, or SET1 enhanced the transactivation of pro-fibrogenic gene promoters by TGF-β in an MRTF-A-dependent manner. In conclusion, MRTF-A regulates liver fibrosis by epigenetically tuning the TGF-β signaling pathway in HSCs. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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