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.
Sheng Li Xue Bao. 2018 Apr 25;70(2):149-157.
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 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.
本研究探讨了血管紧张素II（Ang II）对INS-1胰岛细胞凋亡及硫氧还蛋白相互作用蛋白（TXNIP）表达的影响及其潜在机制。体外培养的INS-1细胞用不同浓度的Ang II处理不同时间，采用细胞计数试剂盒-8（CCK-8）检测细胞活力。用1×10⁻⁷mol/L Ang II处理24 h后，采用流式细胞术和蛋白质印迹法检测细胞凋亡，并用蛋白质印迹法分析TXNIP、碳水化合物反应元件结合蛋白（ChREBP）和血管紧张素II 1型受体（AT1R）的蛋白表达。采用实时荧光定量PCR检测TXNIP和ChREBP mRNA表达。采用免疫荧光/免疫细胞化学法观察TXNIP、ChREBP和AT1R的表达。结果显示，与对照组相比，Ang II以剂量和时间依赖性方式降低细胞活力并诱导TXNIP表达（P<0.05，n = 6）。Ang II诱导细胞凋亡并上调ChREBP和AT1R的表达（P<0.05，n = 6）。AT1R抑制剂替米沙坦（TM）可阻断Ang II诱导的TXNIP和ChREBP过表达（P<0.05，n = 6）并抑制Ang II诱导的细胞凋亡。综上所述，Ang II通过AT1R增加ChREBP激活，进而增加TXNIP表达并促进细胞凋亡。这些发现提示靶向TXNIP在预防糖尿病中Ang II诱导的INS-1细胞凋亡方面具有治疗潜力。
