miR-34a/SIRT1/p53 is suppressed by ursodeoxycholic acid in the rat liver and activated by disease severity in human non-alcoholic fatty liver disease
miR-34a/SIRT1/p53 is suppressed by ursodeoxycholic acid in the rat liver and activated by disease severity in human non-alcoholic fatty liver disease
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DOI：
10.1016/j.jhep.2012.08.008
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发表时间：
2013-01-01
影响因子：
25.7
通讯作者：
Rodrigues, Cecilia M. P.
中科院分区：
文献类型：
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作者：
Castro, Rui E.;Ferreira, Duarte M. S.;Rodrigues, Cecilia M. P.
背景与目的：非酒精性脂肪性肝病(NAFLD)包括从单纯性脂肪变性到非酒精性脂肪性肝炎(NASH)的一系列阶段。然而，疾病的发病机制在很大程度上仍不清楚。最近有报道称，microRNA(miRNA或miR)在人NASH中的表达发生了变化，并在大鼠肝脏中受到熊去氧胆酸(UDCA)的调节。本研究旨在研究人NAFLD中miR-34a/Sirtuin 1(SIRT1)/P53促凋亡通路，并探讨其在大鼠肝脏和原代大鼠肝细胞中的作用及UDCA对其的调节作用。大鼠肝脏取自饲喂0.4%UDCA饲料的动物。原代大鼠肝细胞与胆汁酸或游离脂肪酸(FFAs)孵育，然后用特定的miRNA-34a前体和/或p53过表达载体转染。结果：NFLD肝组织中MIR-34a、细胞凋亡率和乙酰化P53表达随病情加重而增加，而SIRT1表达减弱。UDCA抑制大鼠肝脏和原代大鼠肝细胞miR-34a/SIRT1/P53通路。MIR-34a的过表达证实了其被UDCA靶向，从而阻止了依赖miR-34a的SIRT1、P53乙酰化和细胞凋亡的抑制。UDCA也能抑制FFA对miR-34a高表达细胞的促凋亡作用。最后，P53的过表达激活了miR-34a/SIRT1/P53，进而被UDCA抑制。结论：UDCA特异性调控的miR-34a/SIRT1/P53信号与NAFLD严重程度有关。NAFLD发病机制中潜在的内源性调节因子最终可能为治疗干预提供新的工具。(C)2012年欧洲肝脏研究协会。爱思唯尔出版，版权所有。
Background & Aims: Non-alcoholic fatty liver disease (NAFLD) comprises a spectrum of stages from simple steatosis to nonalcoholic steatohepatitis (NASH). However, disease pathogenesis remains largely unknown. microRNA (miRNA or miR) expression has recently been reported to be altered in human NASH, and modulated by ursodeoxycholic acid (UDCA) in the rat liver. Here, we aimed at evaluating the miR-34a/Sirtuin 1(SIRT1)/p53 proapoptotic pathway in human NAFLD, and to elucidate its function and modulation by UDCA in the rat liver and primary rat hepatocytes.Methods: Liver biopsies were obtained from NAFLD morbid obese patients undergoing bariatric surgery. Rat livers were collected from animals fed a 0.4% UDCA diets. Primary rat hepatocytes were incubated with bile acids or free fatty acids (FFAs) and transfected with a specific miRNA-34a precursor and/or with a p53 overexpression plasmid. p53 transcriptional activity was assessed by ELISA and target reporter constructs.Results: miR-34a, apoptosis and acetylated p53 increased with disease severity, while SIRT1 diminished in the NAFLD liver. UDCA inhibited the miR-34a/SIRT1/p53 pathway in the rat liver in vivo and in primary rat hepatocytes. miR-34a overexpression confirmed its targeting by UDCA, which prevented miR-34a-dependent repression of SIRT1, p53 acetylation, and apoptosis. Augmented apoptosis by FFAs in miR-34a overexpressing cells was also inhibited by UDCA. Finally, p53 overexpression activated miR-34a/SIRT1/p53, which in turn was inhibited by UDCA, via decreased p53 transcriptional activity.Conclusions: Our results support a link between liver cell apoptosis and miR-34a/SIRT1/p53 signaling, specifically modulated by UDCA, and NAFLD severity. Potential endogenous modulators of NAFLD pathogenesis may ultimately provide new tools for therapeutic intervention. (C) 2012 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.