血管紧张素Ⅱ通过其1型受体诱导胰岛β细胞TXNIP的表达  

Angiotensin Ⅱ promotes the expression of TXNIP through angiotensin Ⅱ type 1 receptor in islet β cells

作　　者：冯艳金 王瑾[1] 曹竹杰 李丹[1] 霍海燕 张许梅 焦向英[1] FENG Yan-Jin;WANG Jin;CAO Zhu-Jie;LI Dan;HUO Hai-Yan;ZHANG Xu-Mei;JIAO Xiang-Ying(Department of Physiology, Key Laboratory for Cellular Physiology of Ministry of Education, Shanxi Medical University, Taiyuan 030001, China)

机构地区：[1]山西医科大学生理学系细胞生理学省部共建教育部重点实验室,太原030001

出　　处：《生理学报》2018年第2期149-157,共9页Acta Physiologica Sinica

基　　金：supported by the National Natural Science Foundation of China(No.30800399);the Construction Project of Key Laboratory of Shanxi Province(No.2014011049-12);the Scientific and Technological Innovation Foundation of Shanxi Medical University;China(No.01201406)

摘　　要：本研究旨在探讨血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)对INS-1胰岛细胞凋亡及硫氧还蛋白相互作用蛋白(thioredoxin-interacting protein,TXNIP)表达的影响,并分析其可能的作用机制。体外常规培养大鼠胰岛细胞株INS-1,使用CCK-8试剂盒检测不同浓度和不同作用时间的Ang Ⅱ对细胞存活率的影响,确定最佳作用浓度及作用时间为1×10^(-6) mol/L和24 h;在上述浓度及作用时间条件下,使用流式细胞术及Western blot检测细胞凋亡;Western blot检测Ang Ⅱ对TXNIP、碳水化合物反应元件结合蛋白(carbohydrate response element-binding protein,ChREBP)及血管紧张素Ⅱ 1型受体(angiotensin Ⅱ type 1 receptor,AT1R)蛋白表达的影响;Real-time PCR检测TXNIP及ChREBP mRNA表达;IF/ICC法观察TXNIP、ChREBP及AT1R的表达变化。结果显示Ang Ⅱ可浓度依赖性及时间依赖性地降低细胞活力(P<0.05,n=6)并上调TXNIP的表达(P<0.05,n=6);与对照组相比,Ang Ⅱ组细胞凋亡率、ChREBP及AT1R的表达均明显增高(P<0.05,n=6)。使用AT1R受体抑制剂替米沙坦(telmisartan,TM)后,Ang Ⅱ对INS-1细胞TXNIP及ChREBP的诱导作用被抑制(P<0.05,n=6),Ang Ⅱ诱导的细胞活力降低及细胞凋亡升高被逆转。上述结果表明,Ang Ⅱ可通过AT1R增加ChREBP活化而上调TXNIP的表达,促进细胞凋亡,提示TXNIP可能在糖尿病时Ang Ⅱ诱发胰岛细胞凋亡中发挥作用,并有望成为糖尿病新的治疗靶点。This study investigated the effect of angiotensin Ⅱ（Ang Ⅱ） on apoptosis and thioredoxin-interacting protein（TXNIP） expression in INS-1 islet cells and the underlying mechanism. INS-1 cells cultured in vitro were treated with different concentration of Ang Ⅱ for different time, and the viability was measured using cell counting kit-8（CCK-8）. After treatment with 1 × 10^（-6） mol/L Ang Ⅱ for 24 h, flow cytometry and Western blot were used to measure the cell apoptosis, and Western blot was used to analyze the protein expression of TXNIP, carbohydrate response element-binding protein（ChREBP） and angiotensin Ⅱ type 1 receptor（AT1R）. Real-time PCR was used to detect TXNIP and ChREBP mRNA expression. IF/ICC was used to observe the TXNIP, ChREBP and AT1R expression. The results showed that Ang Ⅱ reduced cell viability and induced the expression of TXNIP in a dose-and time-dependent manner（P〈0.05, n = 6） compared with the control group. Ang Ⅱ induced apoptosis and up-regulated the expression of ChREBP and AT1R（P〈0.05, n = 6）. AT1R inhibitor, telmisartan（TM）, blocked Ang Ⅱ-induced TXNIP and ChREBP overexpression（P〈0.05, n = 6） and inhibited Ang Ⅱ-induced apoptosis. Taken together, Ang Ⅱ increased ChREBP activation through AT1R, which subsequently increased TXNIP expression and promoted cell apoptosis. These findings suggest a therapeutic potential of targeting TXNIP in preventing Ang Ⅱ-induced INS-1 cell apoptosis in diabetes.

关 键 词：血管紧张素Ⅱ 硫氧还蛋白相互作用蛋白 INS-1细胞 碳水化合物反应元件结合蛋白 血管紧张素Ⅱ 1型受体 

分 类 号：R587.1[医药卫生—内分泌]