Yu Fujun, Zheng Yihu, Hong Weilong, Chen Bicheng, Dong Peihong, Zheng Jianjian
Department of Infectious Diseases, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China.
Department of General Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China.
Mol Med Rep. 2015 Dec;12(6):8121-8. doi: 10.3892/mmr.2015.4452. Epub 2015 Oct 16.
Hepatic stellate cells (HSCs) have an important role in liver fibrosis. Epithelial‑to‑mesenchymal transition (EMT), which is promoted by the Hedgehog (Hh) signaling pathway, is involved in the activation of HSCs. MicroRNAs (miRNAs/miRs) have been reported to be involved in the progression of liver fibrosis. A previous study indicated that the activation of HSCs was suppressed by miR‑200a via targeting transforming growth factor‑β2 and β‑catenin. However, whether miR‑200a is able to regulate the EMT in HSCs has remained elusive. The present study revealed that miR‑200a was decreased in vitro and in vivo during liver fibrosis. Furthermore, miR‑200a overexpression resulted in the inhibition of proliferation, α‑SMA expression and extracellular matrix production of activated HSCs. Of note, miR‑200a overexpression reduced myofibroblastic markers, including α‑SMA, type I collagen and desmin, and increased the epithelial cell marker E‑cadherin. These results were further confirmed by immunofluorescence staining. Further study showed that the expression of genes associated with Hh signaling, including Hhip, Shh and Gli1, were not affected by miR‑200a. However, Gli2, a downstream signaling protein of the Hh pathway, was inhibited by miR‑200a and confirmed as a target of miR‑200a using a dual luciferase reporter assay. In addition, the inhibition of the Hh pathway by miR‑200a resulted in an increase of BMP‑7 and Id2 as well as a reduction of Snai1 and S100A4. Collectively, the results of the present study demonstrated that miR‑200a suppressed the EMT process in HSCs, at least in part, via Gli2.
肝星状细胞(HSCs)在肝纤维化中起重要作用。由刺猬信号通路(Hh)促进的上皮-间质转化(EMT)参与肝星状细胞的激活。据报道,微小RNA(miRNAs/miRs)参与肝纤维化的进展。先前的一项研究表明,miR-200a通过靶向转化生长因子-β2和β-连环蛋白抑制肝星状细胞的激活。然而,miR-200a是否能够调节肝星状细胞中的EMT仍不清楚。本研究表明,在肝纤维化过程中,miR-200a在体外和体内均减少。此外,miR-200a过表达导致活化的肝星状细胞增殖、α-SMA表达和细胞外基质产生受到抑制。值得注意的是,miR-200a过表达降低了肌成纤维细胞标志物,包括α-SMA、I型胶原蛋白和结蛋白,并增加了上皮细胞标志物E-钙黏蛋白。免疫荧光染色进一步证实了这些结果。进一步研究表明,与Hh信号相关的基因,包括Hhip、Shh和Gli1的表达不受miR-200a影响。然而,Hh通路的下游信号蛋白Gli2被miR-200a抑制,并通过双荧光素酶报告基因检测证实为miR-200a的靶标。此外,miR-200a对Hh通路的抑制导致BMP-7和Id2增加以及Snai1和S100A4减少。总的来说,本研究结果表明,miR-200a至少部分通过Gli2抑制肝星状细胞中的EMT过程。