Sun Jie, Zhang Huanying, Li Liying, Yu Lianfeng, Fu Lifang
Department of Traditional Chinese Medicine, Shandong Medical College, Linyi, Shandong 276000, P.R. China.
Department of Respiration, Affiliated Hospital of Shandong Medical College, Linyi, Shandong 276000, P.R. China.
Oncol Rep. 2017 Mar;37(3):1698-1706. doi: 10.3892/or.2017.5382. Epub 2017 Jan 17.
Liver fibrosis is a chronic liver disease characterized by the proliferation and activation of hepatic stellate cells (HSCs) and excessive deposition of extracellular matrix (ECM). Research suggests that microRNAs (miRNAs) are a new type of regulator of liver fibrosis. In the present study, we investigated the role of microRNA-9 (miR-9) in the process of liver fibrosis, as well as the underlying mechanism of action. Downregulated levels of miR-9 were found in fibrotic liver tissues and activated HSCs as detected by qRT-PCR; whereas, expression of multidrug resistance‑associated protein 1 (MRP1/ABCC1) was upregulated in the fibrotic liver tissues and activated HSCs. CCK-8 and BrdU assays revealed that miR-9 reduced the proliferative ability of the HSCs. In addition, expression levels of ECM-related genes (α-SMA, Col-1 and Timp-1), which are markers of HSC activation, were downregulated by miR-9. Conversely, an miR-9 inhibitor promoted cell proliferation and HSC activation. In addition, a luciferase reporter assay indicated that miR-9 targets the 3'-untranslated region (3'-UTR) of MRP1 and causes a significant decrease in MRP1. miR-9 inhibited the activation of the Hedgehog (Hh) pathway and the expression of MRP1, while this suppression was rescued by the overexpression of MRP1. Finally, a CCl4-induced mouse model of liver fibrosis was used to investigate the effects of miR-9 on liver fibrosis in vivo. The results showed that miR-9 abrogated hepatic fibrosis by suppressing the expression of MRP1 in CCl4-induced liver fibrotic mice. In conclusion, the present study demonstrated that miR-9 suppresses the proliferation and activation of HSCs through the Hh pathway by targeting MRP1, which suggests that miR-9 has therapeutic potential for liver fibrosis.
肝纤维化是一种慢性肝病，其特征为肝星状细胞（HSCs）的增殖和激活以及细胞外基质（ECM）的过度沉积。研究表明，微小RNA（miRNAs）是肝纤维化的一种新型调节因子。在本研究中，我们探究了微小RNA-9（miR-9）在肝纤维化过程中的作用及其潜在作用机制。通过qRT-PCR检测发现，在纤维化肝组织和激活的HSCs中miR-9水平下调；而在纤维化肝组织和激活的HSCs中，多药耐药相关蛋白1（MRP1/ABCC1）的表达上调。CCK-8和BrdU检测显示，miR-9降低了HSCs的增殖能力。此外，作为HSC激活标志物的ECM相关基因（α-SMA、Col-1和Timp-1）的表达水平被miR-9下调。相反，miR-9抑制剂促进细胞增殖和HSC激活。此外，荧光素酶报告基因检测表明，miR-9靶向MRP1的3'-非翻译区（3'-UTR）并导致MRP1显著降低。miR-9抑制Hedgehog（Hh）信号通路的激活和MRP1的表达，而MRP1的过表达可挽救这种抑制作用。最后，使用CCl4诱导的肝纤维化小鼠模型研究miR-9在体内对肝纤维化的影响。结果显示，在CCl4诱导的肝纤维化小鼠中，miR-9通过抑制MRP1的表达减轻了肝纤维化。总之，本研究表明，miR-9通过靶向MRP1经Hh信号通路抑制HSCs的增殖和激活，这表明miR-9在肝纤维化治疗方面具有潜在应用价值。
