Histone H3K9 demethylase JMJD1A modulates hepatic stellate cells activation and liver fibrosis by epigenetically regulating peroxisome proliferator-activated receptor γ
Histone H3K9 demethylase JMJD1A modulates hepatic stellate cells activation and liver fibrosis by epigenetically regulating peroxisome proliferator-activated receptor γ
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DOI：
10.1096/fj.14-251751
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发表时间：
2015-05-01
期刊：
影响因子：
4.8
通讯作者：
Wang, Haijian
中科院分区：
文献类型：
--
作者：
Jiang, Yan;Wang, Sheng;Wang, Haijian
作为肝纤维化发生的中心事件，肝星状细胞（HSC）转分化涉及脂肪形成转录因子如过氧化物酶体增殖物激活受体γ（PPAR γ）的调控丧失，其在HSC活化期间表观遗传学沉默。我们假设JMJD 1A，一种参与脂肪形成代谢的H3 K9脱甲基酶，可以调节PPAR γ。在人HSC细胞系、大鼠原代HSC和四氯化碳诱导的小鼠肝纤维化模型中，我们使用小干扰或短发夹RNA下调JMJD 1A的表达，并过表达其野生型和突变体。采用染色质免疫沉淀、实时荧光定量RT-PCR和Western blot分析JMJD 1A对PPAR γ基因组蛋白二甲基-H3 K9（H3 k9 me 2）状态以及PPAR γ和纤维化标志物表达的影响，并通过Masson或苏木精-伊红染色分别研究JMJD 1A对肝纤维化和坏死的体外和体内影响。HSC中JMJD 1A敲低与PPAR γ基因启动子中增强的H3 K9 me 2相关，其mRNA和蛋白质的下调导致纤维化标志物表达增加，这可以通过JMJD 1A过表达来持续挽救。原位敲除Jmjd 1a可显著增加α-平滑肌肌动蛋白（P = 0.005）和Col 1a（P = 0.036）的表达，增强胶原的生成（P = 0.028），并显著增强坏死（P = 0.007）。这项研究表明，JMJD 1A作为一种新的表观遗传调节因子，通过靶向PPAR γ基因表达来调节HSC活化和肝纤维化。
As a central event in liver fibrogenesis, hepatic stellate cell (HSC) transdifferentiation involves loss of regulation by adipogenic transcription factors such as peroxisome proliferator-activated receptor gamma; (PPAR gamma), which is epigenetically silenced during HSC activation. We hypothesized that JMJD1A, an H3K9 demethylase involved in adipogenic metabolism, could regulate PPAR gamma. In human HSC cell line, rat primary HSCs, and carbontetrachloride-induced mouse liver fibrogenesis model, we down-regulated the expression of JMJD1A using small interfering or short hairpin RNAs, and overexpressed its wild-type and mutant. We analyzed the effects of JMJD1A manipulation on the histone di-methyl-H3K9 (H3k9me2) status of PPAR gamma gene and the expression of PPAR gamma and fibrosis markers using chromatin immunoprecipitation, real-time quantitative RT-PCR and Western blot, and also investigated the in vitro and in vivo consequences on liver fibrosis and necrosis by Masson or hematoxylin-eosin staining, respectively. JMJD1A knockdown in HSCs correlated with reinforced H3K9me2 in the PPAR gamma gene promoter, and its down-regulation in both mRNA and protein led to increased expression of fibrosis markers, which could be consistently rescued by JMJD1A overexpression. Jmjd1a knockdown in situ resulted in significantly increased expression of alpha-smooth muscle actin (P = 0.005) and Col1a (P = 0.036), strengthened production of collagens (P = 0.028), and remarkably enhanced necrosis (P = 0.007) 4 weeks after treatment. This study suggests JMJD1A as a novel epigenetic regulator that modulates HSC activation and liver fibrosis through targeting PPAR gamma gene expression.