LAG-3敲除加重免疫性肝损伤

LAG⁃3 Knockout Exacerbates Immune Liver Injury

目的:探究淋巴细胞活化基因-3(lymphocyte-activation gene 3,LAG-3)在免疫性肝损伤中的作用及机制。方法:采用尾静脉注射伴刀豆球蛋白A(Concanavalin A,Con A)诱导小鼠急性免疫性肝损伤模型;流式细胞术、实时定量PCR检测肝脏内免疫细胞LAG-3表达;利用LAG-3敲除小鼠研究LAG-3对Con A诱导的免疫性肝损伤的影响,于Con A注射后不同时间点收取外周血,检测血清ALT、AST、细胞因子水平;收集肝脏组织样本进行苏木精-伊红染色(hematoxylin-eosin staining,HE染色)并统计肝脏组织坏死面积;流式细胞术检测肝内细胞分群、T细胞活化;实时定量PCR检测炎症相关基因的表达;酵母双杂交筛选LAG-3相互作用蛋白质。结果:Con A诱导肝脏免疫细胞LAG-3表达增加;LAG-3敲除加重Con A所致小鼠血清转氨酶水平升高、肝脏坏死面积增大、炎症消除延迟;LAG-3敲除不影响Con A诱导的肝内免疫细胞浸润;LAG-3敲除抑制调节性T细胞扩增及IL-10表达;MHCII辅助分子CD74与LAG-3存在蛋白质相互作用。结论:LAG-3敲除加重免疫性肝损伤。

Objective:To investigate the function and mechanism of lymphocyte activation gene 3(LAG⁃3)in immune induced liver injury.Methods:Acute immune liver injury model in mice was induced by tail vein injection of concanavalin A(Con A).LAG⁃3 expression in hepatic immune cells was determined by flow cytometry and real⁃time PCR.LAG⁃3 knockout mice were utilized to study the effect of LAG⁃3 on Con A⁃induced immune liver injury.Peripheral blood was collected at different time points after Con A injection,and the serum levels of ALT,AST,and cytokines were detected.Liver tissue samples were collected for hematoxylin eosin staining(H&E,hematoxylin eosin staining)and the necrotic area of liver tissue was counted.Intrahepatic immune cell subsets and T cell activation were determined by flow cytometry.The expression of inflammation related genes was detected by real⁃time quantitative PCR.Yeast two⁃hybrid screening was performed to find LAG⁃3 interacting proteins.Results:Con A induced an increase in LAG⁃3 expression on hepatic immune cells;LAG⁃3 knockout exacerbated Con A⁃induced elevation of serum transaminase levels,increased necrotic area of the liver,and delayed resolution of inflammation in mice;LAG⁃3 knockout did not affect Con A⁃induced intrahepatic immune cell infiltration;LAG⁃3 knockout suppressed regulatory T cell expansion and IL⁃10 expression;MHCII accessory molecule CD74 interacted with LAG⁃3.Conclusions:LAG⁃3 knockout aggravates immune liver injury.