Department of Molecular Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea.
Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea; University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
Biochim Biophys Acta Mol Cell Biol Lipids. 2019 Dec;1864(12):158521. doi: 10.1016/j.bbalip.2019.158521. Epub 2019 Aug 31.
Although SREBP-1c regulates key enzymes required for hepatic de novo lipogenesis, the mechanisms underlying transcriptional regulation of SREBP-1c in pathogenesis of alcoholic fatty liver is still incompletely understood. In this study, we investigated the role of ERRγ in alcohol-mediated hepatic lipogenesis and examined the possibility to ameliorate alcoholic fatty liver through its inverse agonist. Hepatic ERRγ and SREBP-1c expression was increased by alcohol-mediated activation of CB receptor signaling. Deletion and mutation analyses of the Srebp-1c gene promoter showed that ERRγ directly regulates Srebp-1c gene transcription via binding to an ERR-response element. Overexpression of ERRγ significantly induced SREBP-1c expression and fat accumulation in liver of mice, which were blocked in Srebp-1c-knockout hepatocytes. Conversely, liver-specific ablation of ERRγ gene expression attenuated alcohol-mediated induction of SREBP-1c expression. Finally, an ERRγ inverse agonist, GSK5182, significantly ameliorates fatty liver disease in chronically alcohol-fed mice through inhibition of SREBP-1c-mediated fat accumulation. ERRγ mediates alcohol-induced hepatic lipogenesis by upregulating SREBP-1c expression, which can be blunted by the inverse agonist for ERRγ, which may be an attractive therapeutic strategy for the treatment of alcoholic fatty liver disease in human.
虽然 SREBP-1c 调节肝脏从头合成脂肪所需的关键酶,但酒精性脂肪肝发病机制中 SREBP-1c 转录调控的机制仍不完全清楚。在这项研究中,我们研究了 ERRγ 在酒精介导的肝脂肪生成中的作用,并研究了通过其反向激动剂改善酒精性脂肪肝的可能性。酒精介导的 CB 受体信号激活增加了肝 ERRγ 和 SREBP-1c 的表达。Srebp-1c 基因启动子的缺失和突变分析表明,ERRγ 通过结合 ERR 反应元件直接调节 Srebp-1c 基因转录。ERRγ 的过表达显著诱导了小鼠肝脏中 SREBP-1c 的表达和脂肪积累,而在 Srebp-1c 敲除肝细胞中则被阻断。相反,肝特异性 ERRγ 基因表达的缺失减弱了酒精介导的 SREBP-1c 表达诱导。最后,ERRγ 的反向激动剂 GSK5182 通过抑制 SREBP-1c 介导的脂肪积累,显著改善了慢性酒精喂养小鼠的脂肪肝疾病。ERRγ 通过上调 SREBP-1c 的表达介导酒精诱导的肝脂肪生成,其可以被 ERRγ 的反向激动剂减弱,这可能是治疗人类酒精性脂肪肝的一种有吸引力的治疗策略。