Salvianolic acid B-induced microRNA-152 inhibits liver fibrosis by attenuating DNMT1-mediated Patched1 methylation.
Salvianolic acid B-induced microRNA-152 inhibits liver fibrosis by attenuating DNMT1-mediated Patched1 methylation.
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DOI：
10.1111/jcmm.12655
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发表时间：
2015-11
影响因子：
5.3
通讯作者：
Zheng J
中科院分区：
文献类型：
--
作者：
Yu F;Lu Z;Chen B;Wu X;Dong P;Zheng J
有报道称，上皮-间充质转化(EMT)参与了肝星状细胞(HSCs)的激活，促进了肝纤维化的发展。Hedgehog(HH)途径可促进上皮-间充质转化。Patched1(Ptch1)是HH信号通路的负调控因子，在肝纤维化过程中下调，并与其高甲基化状态有关。据报道，microRNAs(MiRNAs)在HSCs的各种功能调控中起着关键作用。然而，miRNA介导的表观遗传学调控在肝纤维化过程中的EMT研究很少。在这项研究中，丹酚酸B(Sal B)抑制了CCl4处理的小鼠和小鼠原代HSCs的激活，导致细胞增殖、I型胶原和α-平滑肌肌动蛋白的抑制。我们证明Sal B的抗肝纤维化作用至少部分是通过抑制EMT和HH途径实现的。特别是，ptch1的上调与SAL B治疗后DNA甲基化水平的降低有关。相应地，DNA甲基转移酶1(DNMT1)在体内和体外均被丹参B减弱。在丹参B处理的HSCs中，DNMT1基因的敲除增强了ptch1的表达及其去甲基化水平。有趣的是，Sal B处理的细胞中miR-152的增加是导致Sal B对ptch1的低甲基化的原因，荧光素酶活性测定证实，DNMT1是miR-152的直接靶标。进一步的研究表明，miR-152抑制剂逆转了SalB介导的ptch1上调和DNMT1下调。总之，Sal B诱导的miR-152有助于DNMT1下调和表观遗传调节ptch1，从而抑制EMT在肝纤维化中的作用。
Epithelial-mesenchymal transition (EMT) was reported to be involved in the activation of hepatic stellate cells (HSCs), contributing to the development of liver fibrosis. Epithelial-mesenchymal transition can be promoted by the Hedgehog (Hh) pathway. Patched1 (PTCH1), a negative regulatory factor of the Hh signalling pathway, was down-regulated during liver fibrosis and associated with its hypermethylation status. MicroRNAs (miRNAs) are reported to play a critical role in the control of various HSCs functions. However, miRNA-mediated epigenetic regulations in EMT during liver fibrosis are seldom studied. In this study, Salvianolic acid B (Sal B) suppressed the activation of HSCs in CCl4-treated mice and mouse primary HSCs, leading to inhibition of cell proliferation, type I collagen and alpha-smooth muscle actin. We demonstrated that the antifibrotic effects caused by Sal B were, at least in part, via inhibition of EMT and the Hh pathway. In particular, up-regulation of PTCH1 was associated with decreased DNA methylation level after Sal B treatment. Accordingly, DNA methyltransferase 1 (DNMT1) was attenuated by Sal B in vivo and in vitro. The knockdown of DNMT1 in Sal B-treated HSCs enhanced PTCH1 expression and its demethylation level. Interestingly, increased miR-152 in Sal B-treated cells was responsible for the hypomethylation of PTCH1 by Sal B. As confirmed by the luciferase activity assay, DNMT1 was a direct target of miR-152. Further studies showed that the miR-152 inhibitor reversed Sal B-mediated PTCH1 up-regulation and DNMT1 down-regulation. Collectively, miR-152 induced by Sal B, contributed to DNMT1 down-regulation and epigenetically regulated PTCH1, resulting in the inhibition of EMT in liver fibrosis.