尾加压素Ⅱ对大鼠心肌细胞氧化应激/内质网应激及其相关信号通路的影响

Urotensin Ⅱ Induces Oxidative Stress/Endoplasmic Reticulum Stress in Neonatal Cardiomyocytes

目的:探讨尾加压素Ⅱ(UⅡ)对心肌细胞氧化应激(OS)/内质网应激(ERS)及其相关信号通路的影响。方法:本实验将原代培养的Wistar大鼠乳鼠心肌细胞随机分为四组:正常对照组、抗氧化剂N-乙酰半胱氨酸预处理组(NAC 100μmol/L,NAC组)、UⅡ组(UⅡ100 nmol/L)和UⅡ+NAC组(UⅡ100 nmol/L+NAC100μmol/L)。采用2,7-二氯荧光素二乙酸酯(DCFH-DA)作为探针检测各组心肌细胞内活性氧(ROS)的水平。通过实时荧光定量PCR(qRTPCR)、蛋白免疫印迹法(Western blot)检测各组内质网应激的标志性因子葡萄糖调节蛋白78(GRP78)、活性转录因子6(ATF6)、细胞凋亡信号分子CCAAT/增强子结合蛋白同源蛋白(CHOP)及半胱氨酸天冬氨酸蛋白酶12(caspase-12)的表达情况,观察UⅡ对氧化应激及心肌细胞内质网应激信号通路的作用。结果:UⅡ组心肌细胞中ROS表达水平较UⅡ+NAC组、正常对照组、NAC组明显增强,差异有统计学意义(P<0.05)。qRT-PCR、Western blot结果显示,UⅡ组中ATF6、GRP78、CHOP和caspase-12的mRNA及蛋白表达量均较UⅡ+NAC组、正常对照组、NAC组明显增强,差异有统计学意义(P<0.05)。结论:UⅡ可以诱导心肌细胞氧化应激及内质网应激的激活,而抗氧化剂预处理可以明显减轻UⅡ诱导的氧化应激、内质网应激及相关信号通路的激活,提示UⅡ可能通过氧化应激进一步激活内质网应激及相关信号通路。

Objectives:The purpose of this study was to investigate the effect of urotensinⅡ(UⅡ)on oxidative stress(OS)/endoplasmic reticulum stress(ERS)and its related signaling pathway in neonatal cardiomyocytes.Methods:Neonatal cardiomyocytes were divided into four groups:normal control group,UII group(100 nmol/L),antioxidant N-acetylcysteine(NAC,10μmol/L)group and UⅡ+NAC group(UⅡ100 nmol/L+NAC 100μmol/L).Intracellular reactive oxygen species(ROS)production was detected by DCFH-DA method.Glucose-regulated protein 78(GRP78,the Endoplasmic reticulum molecular chaperone),activating transcription factor 6(ATF6,the ERS sensor protein),C/EBPhomologous protein(CHOP)and cysteine-containing aspartate-specific proteases 12(caspase-12)were determined by quantitative real-time reverse transcription–polymerase chain reaction and Western blot.Results:Our results showed that UⅡsignificantly increased the intracellular level of ROS as compared with UⅡ+NAC group,control group or NAC group(all P<0.05).The expression of GRP78,ATF6,CHOP and caspase-12 were also significantly upregulated in UⅡgroup when compared with UⅡ+NAC group,control group or NAC group.Conclusions:UⅡ-induced ERS in neonatal cardiomyocytes is ROS-dependent and might be mediated through ATF6/CHOP-caspase-12 axis.