Ge Shanfei, Xiong Ying, Wu Xiaoping, Xie Jianping, Liu Fei, He Jinni, Xiang Tianxing, Cheng Na, Lai Lingling, Zhong Yuanbin
Department of Infectious Disease, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
Department of Infectious Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China.
Biomed Pharmacother. 2017 Aug;92:942-951. doi: 10.1016/j.biopha.2017.05.142. Epub 2017 Jun 10.
Growth Factor Receptor-bound 2 (GRB2) plays a crucial role in regulation of cellular function including proliferation and differentiation, and we previously identified GRB2 as promoting HSCs (HSCs) proliferation. However, the underlying mechanisms that are involving in the regulation of GRB2 in hepatic fibrogenesis remain unknown.
In the present study, we tested the function of GRB2 in hepatic fibrosis. Hepatic fibrosis was induced by subcutaneous CCl administration at a dose of 3mL/kg in rats. The rat HSC cell line HSC-T6 were cultured for proliferation investigation by CCK-8 and BrdU incorporation method. The levels of GRB2, HMGB1, PI3K/AKT, COL1A1 and α-SMA were analyzed by western blot or real-time PCR.
showed that the expression of GRB2 and HMGB1 was obviously increased in liver tissues of hepatic fibrosis rats accompanied by up-regulation of COL1A1 and α-SMA. In cultured HSCs, application of exogenous HMGB1 induced cell proliferation and cell proliferation rate concomitantly with up-regulation of GRB2 expression and PI3K/AKT phosphorylation. The effects of HMGB1-induced proliferation of HSCs and up-regulation of COL1A1 and α-SMA were abolished by GRB2 siRNA. HMGB1-induced proliferation of HSCs and up-regulation of COL1A1 and α-SMA was reversed in the presence of LY294002, an inhibitor of PI3K inhibitor.
These findings suggest that GRB2 plays an important role in CCl-induced hepatic fibrosis by regulating HSCs' function, and up-regulation of GRB2 induced by HMGB1 is mediated via the PI3K/AKT pathway.
生长因子受体结合蛋白2（GRB2）在包括增殖和分化在内的细胞功能调节中起关键作用，我们之前鉴定出GRB2可促进肝星状细胞（HSCs）增殖。然而，GRB2在肝纤维化调节中的潜在机制仍不清楚。
在本研究中，我们测试了GRB2在肝纤维化中的作用。通过皮下注射剂量为3mL/kg的四氯化碳（CCl）诱导大鼠肝纤维化。培养大鼠肝星状细胞系HSC-T6，采用CCK-8和BrdU掺入法进行增殖研究。通过蛋白质免疫印迹法或实时聚合酶链反应分析GRB2、高迁移率族蛋白B1（HMGB1）、磷脂酰肌醇-3激酶/蛋白激酶B（PI3K/AKT）、I型胶原蛋白α1（COL1A1）和α-平滑肌肌动蛋白（α-SMA）的水平。
结果显示，肝纤维化大鼠肝组织中GRB2和HMGB1的表达明显增加，同时COL1A1和α-SMA上调。在培养的肝星状细胞中，外源性HMGB1的应用诱导细胞增殖和细胞增殖率，同时GRB2表达上调和PI3K/AKT磷酸化。GRB2小干扰RNA消除了HMGB1诱导的肝星状细胞增殖以及COL1A1和α-SMA的上调。在存在PI3K抑制剂LY294002的情况下，HMGB1诱导的肝星状细胞增殖以及COL1A1和α-SMA的上调被逆转。
这些发现表明，GRB2通过调节肝星状细胞功能在四氯化碳诱导的肝纤维化中起重要作用，并且HMGB1诱导的GRB2上调是通过PI3K/AKT途径介导的。
