钙调神经磷酸酶在cTnI基因Asp128Tyr突变致心肌肥大中的作用

Role of calcineurin in cTnI Asp128Tyr mutation-induced myocardial hypertrophy

目的:探讨钙调神经磷酸酶(CaN)在心肌钙蛋白I(cTnI)基因第128位天冬氨酸→酪氨酸(Asp128Tyr)突变致心肌肥大中的作用。方法:乳鼠心肌细胞,以心钠素(ANF)、脑钠肽(BNP)mRNA表达作为心肌肥大指标,观察含cTnI Asp128Tyr突变基因的腺病毒转染对心肌细胞的作用,并观察CaN抑制剂环孢菌素A(CsA)或FK506对突变基因转染的影响。Real-time PCR检测ANF、BNP和CaN mRNA表达变化,同时行CaN活性测定。结果:转染含cTnI Asp128Tyr突变基因腺病毒的心肌细胞增大,胞内ANF和BNP的mRNA表达较空白对照组、不含任何目的基因的阴性对照腺病毒转染组和转染含野生型cTnI基因的腺病毒组增高(P<0.05)。与含野生型cTnI基因的腺病毒组相比,转染含cTnI Asp128Tyr突变基因的腺病毒组在ANF和BNP mRNA表达升高的同时存在CaN活性升高和CaN mRNA表达上调(P<0.05)。转染含cTnI Asp128Tyr突变基因的腺病毒并用CsA或FK506干预后,心肌细胞缩小,胞内ANF和BNP mRNA表达量较单纯转染含cTnI Asp128Tyr突变基因的腺病毒组降低(P<0.05),同时心肌细胞内CaN活性显著下降(P<0.05),CaN mRNA表达下调(P<0.05)。结论:cTnI Asp128Tyr突变可引起心肌细胞肥大;CaN信号通路参与了cTnI Asp128Tyr突变致心肌肥大过程的调控。

AIM：To investigate the role of calcineurin （CaN） signaling pathways in myocardial hypertrophy induced by cTnI Asp128Tyr mutation. METHODS： The adenovirus conlaining cTnI Asp128Tyr mutation was transfeeted into the cultured neonatal rat cardiomyocytes.Cardliac hypertrophy was evaluated by determining the mRNA expression of atrial natriure-tic factor（ANF） and brain natriuretic peptide（BNP）in the transfected ceils, The effects of CaN inhibitors eyclosporine A（CsA） and FK506 on cardiac hypertroply were also observed.The mRNA expres-sion of ANF ,BNP and CaN was measured by real-time quantitative PCR.The aetivity of CaN eas detected.RESULTS：Compared with blank control group,negative control virus group or virus conlaining wildtype cTnI gene group,the mRNA expression of ANF and BNP in mutation group（transfected with the adenovirus containing cTnI Asp 128Tyr mutation）significantly increased,and decreased after treatment with CsA or FK506.The mRNA exression and activity of CaN inerrased in the mutation group compared with blank control group,negative eontrol virus group or virus containing wildtype cTnI gene.At the same time,the mRNA expression and the activity of CaN decreased after treatment with CsA or FK506.CONCLUSION：Calcineurin signaling pathway is involved in the cardiac hypertophy induced by cTnI Asp128Tyr mutation.