IL-13诱导 STAT6磷酸化及促进人肝星状细胞的纤维化作用

IL-13 induces STAT6 phosphorylation and promotes fibrosis in human hepatic stellate cells

目的：探索白细胞介素-13（ IL-13）对人肝星状细胞（ hepatic stellate cell ）纤维化作用的影响及其分子机制。方法采用MTT方法观察IL-13对人肝星状细胞株LX-2增殖的影响；RT-PCR技术检测LX-2细胞Ⅰ型胶原蛋白（ collagen typeⅠ， COLⅠ） mRNA表达；ELISA和羟脯氨酸实验定量检测IL-13对LX-2细胞分泌COLⅠ的影响；Western blot技术分析IL-13对LX-2细胞的信号转导子和转录激活子6（ STAT6）磷酸化的影响。结果 IL-1310 ng／ml组、20 ng／ml组和50 ng／ml组LX-2细胞增殖显著高于空白对照组（P＜0．05），并呈现剂量依赖关系；加入IL-1350 ng／ml显著上调了LX-2细胞COLⅠmRNA和蛋白的表达（P＜0．05），低浓度IL-13（5 ng／ml、10 ng／ml、20 ng／ml）对LX-2细胞COLⅠmRNA和蛋白的表达无显著影响（P＞0．05）；IL-13（50 ng／ml）作用LX-2细胞，60 min组和120 min组磷酸化STAT6蛋白表达显著增强（P＜0．05）。结论 IL-13促进人肝星状细胞增殖并上调COLⅠmRNA和蛋白表达，IL-13促进人肝星状细胞的纤维化作用的可能机制是激活STAT6磷酸化。

Objective To investigate the effects of IL-13 on fibrosis in hepatic stellate cells and its molecular mechanism .Methods The effects of IL-13 on the proliferation of hepatic stellate cell line LX-2 were measured by MTT assay .The transcription level of collagen typeⅠ（ COLⅠ） in LX-2 cells was detec-ted by RT-PCR.The secretion of COLⅠin LX-2 cells was measured by ELISA assay and hydroxyproline as-say.Western blot assay was used to analyze the effects of IL-13 on the phosphorylation of signal transducer and activator of transcription（STAT6）.Results Compared with control group, IL-13 （10 ng/ml, 20 ng/ml and 50 ng/ml ） significantly stimulated the proliferation of LX-2 cells in a dose-dependent manner （ P〈0.05）.The expression of collagen typeⅠin LX-2 cells at mRNA and protein levels were significantly up-regulated by IL-13 at a concentration of 50 ng/ml （P〈0.05）, but not affected by IL-13 at low concentra-tions （5 ng/ml, 10 ng/ml, and 20 ng/ml） （P〉0.05）.The expression of phosphorylated STAT6 protein in LX-2 cells was significantly enhanced upon the stimulation with 50 ng/ml of IL-13 （ P〈0.05 ） for60 min or 120 min.C onclusion IL-13 promoted the proliferation of human hepatic stellate cells and up-regulated the expression of COLⅠat mRNA and protein levels .IL-13 might promote the fibrosis in human hepatic stellate cells through activating STAT 6 phosphorylation .