β-arrestin2通过调控自噬水平在结肠炎中的作用
Role of β-arrestin2 in colitis by regulating autophagy
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摘要: 目的 研究β-抑制蛋白2 (β-arrestin2)是否通过调控自噬水平在结肠炎中发挥作用。方法 β-arrestin2野生型(WT)小鼠和β-arrestin2基因敲除(KO)小鼠各20只,随机分为4组,每组各10只,分别为β-arrestin2 WT对照组和实验组,β-arrestin2 KO对照组和实验组。实验组小鼠自由饮用3%葡聚糖硫酸钠7 d诱导急性溃疡性结肠炎,对照组给予无菌ddH2O。观察并记录各组小鼠的疾病活动指数。收集小鼠结肠组织,免疫组织化学和蛋白免疫印迹法检测自噬相关蛋白微管相关蛋白1轻链3β(LC3B)、Beclin1的表达水平。在HCoEpiC细胞中,通过siRNA沉默β-arrestin2的表达,Earle’s平衡盐溶液(EBSS)处理细胞以诱导细胞自噬的发生,检测LC3B表达水平。结果 β-arrestin2 WT实验组小鼠的结肠黏膜自噬相关蛋白表达水平上调,而β-arrestin2 KO实验组小鼠的结肠炎症程度明显改善,自噬相关蛋白LC3B-Ⅱ/Ⅰ表达水平下降(P < 0.05),但Beclin1表达水平比较差异无统计学意义(P > 0.05)。在HCoEpiC细胞中沉默β-arrestin2的表达,EBSS处理后,LC3B-Ⅱ/Ⅰ表达水平下调。结论 在结肠炎中,β-arrestin2调控自噬水平,当β-arrestin2缺失时,可以通过抑制自噬改善结肠炎。Abstract: Objective To explore whether β-arrestin2 plays a role by regulating autophagy in colitis. Methods 20 β-arrestin2 wild-type (WT) and 20 β-arrestin2 knockout (KO) mice were randomly and evenly divided into four groups, including β-arrestin2 WT control group and experimental group, β-arrestin2 KO control group and experimental group. In the experimental groups, the mice were given free access to 3% dextran sulfate sodium (DSS) for 7 d to induce acute colitis. In the control groups, the mice were given sterile ddH2O. The disease activity index of mice was observed and recorded in each group. The colon tissues of mice were collected, and the expression levels of autophagy-related proteins including LC3B and Beclin1 were observed and detected by immunohistochemistry and western blot. The expression of β-arrestin2 was knockdown by siRNA in HCoEpiC cells, and then the cells were treated by Earle’s Balanced Salt Solution (EBSS) to induce autophagy. Then, the expression level of LC3B protein was detected. Results The expression of autophagy-related proteins was significantly up-regulated in the colon mucosal tissues of WT experimental mice. Compared with WT mice, the colonic inflammation was significantly ameliorated in β-arrestin2 KO mice after DSS treatment. And the expression levels of autophagy-related proteins LC3B-Ⅱ/Ⅰ were significantly down-regulated in β-arrestin2 KO mice in the experimental groups(P < 0.05).There is no significant difference in the expression levels of Beclin1(P > 0.05). After knocking down the expression of β-arrestin2 in HCoEpiC cells and EBSS treatment, the expression levels of LC3B-Ⅱ/Ⅰ were significantly down-regulated (P < 0.05). Conclusion β-arrestin2 can regulate the autophagy in colitis, and the deficiency of β-arrestin2 can inhibit autophagy to ameliorate the colonic inflammation.
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