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血管紧张素II通过其1型受体诱导胰岛β细胞TXNIP的表达

冯艳金, 王瑾, 曹竹杰, 李丹, 霍海燕, 张许梅, 焦向英^*

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

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。

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

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

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

Abstract

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.

Key words: angiotensin II; thioredoxin-interacting protein; INS-1 cells; carbohydrate response element-binding protein; angiotensin II type 1 receptor

收稿日期：2017-09-25　　录用日期：2018-01-30

通讯作者：焦向英　　E-mail: jiaoxyty@163.com

DOI: 10.13294/j.aps.2018.0013

引用本文：

冯艳金, 王瑾, 曹竹杰, 李丹, 霍海燕, 张许梅, 焦向英. 血管紧张素II通过其1型受体诱导胰岛β细胞TXNIP的表达[J]. 生理学报 2018; 70 (2): 149-157.

FENG Yan-Jin, Wang Jin, CAO Zhu-Jie, LI Dan, HUO Hai-Yan, ZHANG Xu-Mei, JIAO Xiang-Ying. Angiotensin II promotes the expression of TXNIP through angiotensin II type 1 receptor in islet β cells. Acta Physiol Sin 2018; 70 (2): 149-157 (in Chinese with English abstract).