内源性sestrin2参与抑制心肌梗死后内质网应激所诱导细胞凋亡

李博涛; 邢玉洁; 马美娟; 王军奎; 赵娜

doi:10.12125/j.chj.201811028

内源性sestrin2参与抑制心肌梗死后内质网应激所诱导细胞凋亡

Endogenous sestrin2 is involved in inhibiting endoplasmic reticulum stress mediated apoptosis after myocardial infarction

摘要

摘要:
目的探讨sestrin2在心梗（MI）后内质网应激中的变化及作用。
方法结扎大鼠前降支制作MI模型建立MI组，仅开胸建立Sham组；应用衣霉素刺激新生大鼠心肌细胞建立细胞内质网应激模型（衣霉素组）应用磷酸盐缓冲溶液（PBS）为对照组。原位切口末端标记法（TUNEL）评估组织水平细胞凋亡，流式细胞仪检测细胞凋亡率。蛋白免疫印迹法检测葡萄糖调节蛋白（GRP）78、CCAAT-增强子结合蛋白（CHOP）、sestrin2表达水平。
结果与Sham组相比，MI大鼠心脏组织中内质网应激激活，GRP 78及CHOP表达水平增加（均P < 0.01），心肌细胞凋亡增加（P < 0.01），伴随内源性sestrin2蛋白表达水平上调（P < 0.01）。与对照组相比，衣霉素刺激新生大鼠心肌细胞激活内质网应激，GRP 78及CHOP蛋白表达水平增加（P < 0.01，P < 0.05），心肌细胞凋亡表型增加（P < 0.01）。在此基础上，转染sestrin2-siRNA抑制心肌细胞sestrin2表达后，CHOP蛋白表达上调（P < 0.05），心肌细胞凋亡增加（P < 0.05）。
结论内源性sestrin2参与抑制心肌缺血后内质网应激诱导心肌细胞凋亡。

Abstract:
AIM To reveal the change and role of sestrin2 in the rats after myocardial infarction (MI) following endoplasmic reticulum (ER) stress activated.
METHODS MI group rats were induced by ligation of left anterior descending coronary artery (LAD), sham group rats were induced by the same procedure except LAD ligation. ER stress activated model in cardiomyocytes by treated with tunicamycin (Tunicamycin group), cardioyocytes by treated with PBS were Control group. Apoptotic cardiomyocytes were detected by terminal transferase UTP nick end labelling (TUNEL) assays and flow cytometric analysis, respectively. Glucose regulagted protein 78 (GRP78), CCAAT-enhancer binding protein homologous protein (CHOP) and sestrin2 protein expression were reavealed by western blot analyses.
RESULTS In MI rats with ER stress activated conferred increased levels of GRP78 (P < 0.01), CHOP (P < 0.01) sestrin2 (P < 0.01) protein expression.Cardiomyocytes apoptosis also showed increased (P < 0.01) after MI.In cardiomyocytes treated with tunicamycin, GRP78 (P < 0.01), CHOP (P < 0.05), sestrin2 (P < 0.01) protein expression upregulated significantly. Meanwhile, apoptotic rates was also increased (P < 0.01). Moreover, inhibition of sestrin2 in cardiomyocytes treated with tunicamycin, CHOP protein (P < 0.05) expression showed upregulated and apoptotic rates of cardiomyocytes was also increased (P < 0.05) compared with cardiomyocytes treated with tunicamycin alone.
CONCLUSION Endogenous sestrin2 is involved in inhibiting endoplasmic reticulum stress mediated apoptosis after myocardial infarction.

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