Wu Yuting, Bu Fangtian, Yu Haixia, Li Wanxia, Huang Cheng, Meng Xiaoming, Zhang Lei, Ma Taotao, Li Jun
School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China; Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China; Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China.
School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China; Institute for Liver Diseases of Anhui Medical University, ILD-AMU, Anhui Medical University, Hefei 230032, China; Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei 230032, China.
Toxicol Appl Pharmacol. 2017 Jan 15;315:35-49. doi: 10.1016/j.taap.2016.12.002. Epub 2016 Dec 6.
Liver fibrosis, resulting from chronic and persistent injury to the liver, is a worldwide health problem. Advanced liver fibrosis results in cirrhosis, liver failure and even hepatocellular cancer (HCC), often eventually requiring liver transplantation, poses a huge health burden on the global community. However, the specific pathogenesis of liver fibrosis remains not fully understood. Numerous basic and clinical studies have provided evidence that epigenetic modifications, especially DNA methylation, might contribute to the activation of hepatic stellate cells (HSCs), the pivotal cell type responsible for the fibrous scar in liver. Here, reduced representation bisulfite sequencing (RRBS) and bisulfite pyrosequencing PCR (BSP) analysis identified hypermethylation status of Septin9 (Sept9) gene in liver fibrogenesis. Sept9 protein was dramatically decreased in livers of CCl4-treated mice and immortalized HSC-T6 cells exposed to TGF-β1. Nevertheless, the suppression of Sept9 could be blocked by DNMT3a-siRNA and DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-azadC). Overexpressed Sept9 attenuated TGF-β1-induced expression of myofibroblast markers α-SMA and Col1a1, accompanied by up-regulation of cell apoptosis-related proteins. Conversely, RNAi-mediated silencing of Sept9 enhanced accumulation of extracellular matrix. These observations suggested that Sept9 contributed to alleviate liver fibrosis might partially through promoting activated HSCs apoptosis and this anti-fibrogenesis effect might be blocked by DNMT-3a mediated methylation of Sept9. Therefore, pharmacological agents that inhibit Sept9 methylation and increase its expression could be considered as valuable treatments for liver fibrosis.
肝纤维化是一种全球性的健康问题，由肝脏长期持续损伤引起。晚期肝纤维化会导致肝硬化、肝衰竭甚至肝细胞癌（HCC），最终往往需要进行肝移植，给全球社会带来了巨大的健康负担。然而，肝纤维化的具体发病机制仍未完全明确。大量基础和临床研究表明，表观遗传修饰，尤其是DNA甲基化，可能促使肝星状细胞（HSCs）活化，而肝星状细胞是肝脏纤维瘢痕形成的关键细胞类型。在此，通过简化代表性亚硫酸氢盐测序（RRBS）和亚硫酸氢盐焦磷酸测序PCR（BSP）分析，确定了Septin9（Sept9）基因在肝纤维化形成过程中的高甲基化状态。在CCl4处理的小鼠肝脏以及暴露于TGF-β1的永生化HSC-T6细胞中，Sept9蛋白显著减少。然而，DNMT3a-siRNA和DNA甲基转移酶抑制剂5-氮杂-2'-脱氧胞苷（5-azadC）可阻断Sept9的抑制作用。过表达的Sept9可减弱TGF-β1诱导的成肌纤维细胞标志物α-SMA和Col1a1的表达，并伴随细胞凋亡相关蛋白的上调。相反，RNAi介导的Sept9沉默增强了细胞外基质的积累。这些观察结果表明，Sept9可能部分通过促进活化的肝星状细胞凋亡来减轻肝纤维化，而这种抗纤维化作用可能会被DNMT-3a介导的Sept9甲基化所阻断。因此，抑制Sept9甲基化并增加其表达的药物可被视为治疗肝纤维化的有效方法。
