硫氧还蛋白相互作用蛋白介导的炎症反应及细胞凋亡在心肌梗死中的作用

Role of thioredoxin-interacting protein-mediated inflammatory response and apoptosis in myocardial infarction

背景:近年来有研究发现,在心肌梗死小鼠的心肌组织中,硫氧还蛋白相互作用蛋白表达升高。硫氧还蛋白相互作用蛋白是核苷酸结合寡聚化域样受体蛋白3(nucleotide-binding oligomerization domain-like receptor family pyrin domain-like receptor containing pyrin domain 3,NLRP3)炎性小体的内源性激活物,那么,其是否通过激活炎症小体参与心肌梗死的病理过程目前尚不清楚。目的:探讨硫氧还蛋白相互作用蛋白对心肌梗死后心肌细胞凋亡和NLRP3炎症小体的影响,为临床心肌梗死的预防和治疗提供新思路。方法:选取8周龄雄性硫氧还蛋白相互作用蛋白基因敲除纯合子小鼠30只和同窝野生C57BL/6J小鼠30只,2种小鼠均随机分为心肌梗死组和伪手术组(n=15),建立心肌梗死模型。术后4 d取部分小鼠(n=10)麻醉处死,取心脏组织,TUNEL法(n=5)检测心肌细胞凋亡水平,Western blot(n=5)检测硫氧还蛋白相互作用蛋白、NLRP3、活化半胱氨酸天冬氨酸蛋白水解酶1、凋亡相关斑点样蛋白、活化白细胞介素1β和活化半胱氨酸天冬氨酸蛋白水解酶3蛋白的表达水平;其余小鼠(n=5)于术后1个月采用小动物超声仪检测心脏功能,随后麻醉处死留取心脏组织,用于其他指标检测。结果与结论:①与野生伪手术组相比,野生心梗组硫氧还蛋白相互作用蛋白的表达水平显著升高(P<0.05);②与各自伪手术组相比,野生心肌梗死小鼠和硫氧还蛋白相互作用蛋白基因敲除心肌梗死小鼠的心肌中NLRP3活化半胱氨酸天冬氨酸蛋白水解酶1、凋亡相关斑点样蛋白、活化白细胞介素1β和活化半胱氨酸天冬氨酸蛋白水解酶3等蛋白表达均明显上调(P<0.05);③与野生心肌梗死小鼠相比,硫氧还蛋白相互作用蛋白基因敲除心肌梗死小鼠的梗死心肌中上述5种蛋白表达均明显降低,心肌细胞凋亡减少,心功能明显改善(P<0.05);④证明硫氧还蛋白相互作用蛋白基因敲除可抑制心肌梗死后NLRP3、活化半胱氨酸天冬氨酸蛋白水解酶1、凋亡相关斑点样蛋白、活化白细胞介素1β和活化半胱氨酸天冬氨酸蛋白水解酶3的表达,减少心肌细胞凋亡,最终改善缺血心脏功能,有望为临床心肌梗死的治疗提供靶点。

BACKGROUND:In recent years,studies have found that the expression of thioredoxin-interacting protein is increased in the myocardial tissue of mice with myocardial infarction.Thioredoxin-interacting protein is the endogenous activator of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-like receptor containing pyrin domain 3(NLRP3)inflammasome.It is unclear whether it participates in the pathological process of myocardial infarction by activating the inflammasome.OBJECTIVE:To investigate the effects of thioredoxin-interacting protein on cardiomyocyte apoptosis and NLRP3 inflammasomes,thereby providing new ideas for the prevention and treatment of myocardial infarction.METHODS:A total of 30 thioredoxin-interacting protein knockout mice and 30 wild-type littermate C57BL/6 mice were selected and randomly divided into myocardial infarction group and sham operation group with 15 mice in each group.Myocardial infarction models were established.Four days after the operation,some mice(10 mice in each group)were sacrificed and the heart tissue was collected.TdT-mediated dUTP nick end labeling was used to detect cardiomyocyte apoptosis in mice(5 mice in each group).Western blot(5 mice in each group)was used to detect the expression of thioredoxin-interacting protein,NLRP3,cleaved cysteinyl aspartate specific proteinase-1,apoptosis-associated speck-like protein containing CARD,cleaved interleukin-1β,and cleaved cysteinyl aspartate speacific proteinase-3.The remaining mice(5 mice in each group)were fed till 1 month after the operation.The cardiac function was detected by echocardiography before the mice were sacrificed and heart tissue samples were collected for later use.RESULTS AND CONCLUSION:The expression level of thioredoxin-interacting protein was significantly upregulated in the wild-type myocardial infarction group than the wild-type sham operation group(P<0.05).Compared with the sham operation groups,the expressions of NLRP3,cleaved cysteinyl aspartate specific proteinase-1,apoptosis-associated speck-like protein containing CARD,cleaved interleukin-1β,and cleaved cysteinyl aspartate specific proteinase-3 proteins in the myocardium were significantly upregulated in the two myocardial infarction groups(P<0.05).Compared with the wild-type myocardial infarction group,the expression levels of the above-mentioned five proteins were significantly downregulated,the cardiomyocyte apoptosis was reduced,and the cardiac function was significantly improved in the thioredoxin-interacting protein knockout mice with myocardial infarction(P<0.05).To conclude,thioredoxininteracting protein knockout can inhibit the expression of NLRP3,cleaved cysteinyl aspartate specific proteinase-1,apoptosis-associated speck-like protein containing CARD,cleaved interleukin-1β,and cleaved cysteinyl aspartate specific proteinase-3 proteins,reduce cardiomyocyte apoptosis,and thereby improve cardiac function after myocardial infarction.It is expected to provide a target for the clinical treatment of myocardial infarction.