谷氧还蛋白1调节高糖诱导的心肌细胞自噬

Glutaredoxin 1 Regulates High Glucose-induced Autophagy in Cardiomyocytes

人谷氧还蛋白1（Grx1）在体内具有广泛的抗氧化、抗凋亡作用,与氧化应激损伤导致的糖尿病和心肌病等多种疾病的发病机制密切相关.研究表明,糖尿病心血管病与自噬调节异常密切相关,但糖尿病心血管病变时自噬水平如何调节才能够保护受损的心肌还尚未定论.为研究自噬在高糖诱导心肌细胞凋亡中的作用及其与Grx1的关系,以明确Grx1对高糖诱导的心肌细胞凋亡的抑制作用及相关机制,本研究以高糖诱导大鼠心肌细胞H9c2建立高糖损伤模型,采用氧化还原蛋白免疫印迹法检测蛋白质的氧化水平.免疫印迹检测活性caspase 3蛋白和自噬蛋白Beclin1和LC3以及抗凋亡蛋白Bcl-2的表达水平.研究发现,高糖可诱导蛋白质的氧化水平增加,而Grx1可拮抗高糖诱导的H9c2细胞中蛋白质的氧化.并且含血清的高糖（25和50 mmol/L）作用H9c2心肌细胞后,自噬蛋白Beclin 1表达水平在6-48 h显著上调.同时发现,活性caspase 3水平也呈时间依赖性表达上调,caspase 3和自噬蛋白表达水平的同趋势增加,说明升高的自噬水平与心肌细胞凋亡的调节有关.Grx1保护组的自噬蛋白及活性caspase 3表达水平均显著下调,Grx1抑制剂镉组可拮抗Grx1调节的自噬蛋白和凋亡蛋白水平,说明Grx 1通过抑制自噬及caspase 3水平抑制高糖诱导的心肌细胞凋亡.以上研究结果提示,通过提高Grx1/GSH抗氧化系统功能,调节氧化还原稳态,可以有效减少高糖诱导的心肌损伤,保护糖尿病心脏功能.

Human glutaredoxin 1 （Grx1） is a primary antioxidant protein of anti-oxidant and antiapoptosis effects responsible for many biological functions. Grx1 related to pathogenesis of diabetes,cardiomyopathy and other diseases with oxidative stress-mediated tissue damages. Several studies have demonstrated that diabetes mellitus with complicated angiocardiopathy appeared to be associated with the abnormality of autophagy regulation. However, is it possible to regulate autophagy to protect myocardium in diabetes remained unclear. We investigated the effect of autophagy activation on high glucose-induced cardiomyocyte apoptosis and how much Grx1 was involved in the regulation of autophagy. The oxidative modification of proteins was evaluated by using Redox Western blot, autophagy-related proteins of Beclin1, microtubule associated protein 1 light chain 3 （LC3） , caspase-3 and anti-apoptotic protein Bcl2 were detected by Western blot. The resuh showed that the protein oxidation was increased in H9c2 cells after high glucose treatments,and Grxl antagonized the effect. Beclinl was up-regulated after treatment with 25 mmol/L and 50 mmol/L glucose for 6 to 48 hours as well as the active form of caspase-3. In the Grx1 protected group, Beclinl and caspase-3 levels were dramatically down-regulated, but not in the Grxl inhibitor Cd2＋ group. These data indicated that activation of Grx1/GSH antioxidant system might reduce cardiomyocyte apoptosis and protect cardiac function in diabetes.