蛋白酶N1对小鼠心肌细胞增殖的作用及机制

Effect and mechanism of protein kinase N1 on the proliferation of mouse cardiomyocytes

目的探讨蛋白酶N1(PKN1)对小鼠心肌细胞增殖的作用及机制。方法使用异氟烷麻醉1日龄小鼠2只,分离小鼠心肌细胞,并分为对照组和干扰组,干扰组心肌细胞转染PKN1干扰片段,对照组细胞转染对照片段。按照随机数字表法将10只小鼠分为正常组和观察组,每组5只。观察组小鼠于心脏原位注射PKN1干扰腺病毒,正常组小鼠于心脏原位注射空载腺病毒。采用免疫荧光法检测4组小鼠心肌细胞或心肌组织中Ki-67阳性表达率,以Ki-67阳性表达率表示心肌细胞增殖能力;采用实时荧光定量聚合酶链式反应法检测对照组和干扰组小鼠心肌细胞中PKN1 mRNA表达;采用Western blot法检测对照组和干扰组小鼠心肌细胞中PKN1和cyclin D1蛋白表达。结果干扰组心肌细胞中Ki-67阳性表达率均显著低于对照组(t=11.201,P<0.01),观察组小鼠心肌组织中Ki-67阳性表达率显著低于正常(t=11.851,P<0.01)。干扰组心肌细胞中PKN1 mRNA相对表达量显著低于对照组(t=7.022,P<0.01)。干扰组心肌细胞中PKN1和cyclin D1蛋白相对表达量均显著低于对照组(t=5.762、6.884,P<0.01)。结论小鼠心肌细胞中PKN1表达降低可抑制cyclin D1蛋白表达,从而抑制心肌细胞增殖。

Objective To explore the effect and mechanism of protein kinase N1(PKN1)on the proliferation of mouse cardiomyocytes.Methods Two 1-day-old mice were anesthetized with isoflurane,and their cardiomyocytes were isolated and divided into the control group and the interference group.The cardiomyocytes in the interference group were transfected with PKN1 fragments,while the cardiomyocytes in the control group were transfected with control fragments.According to the random number table method,10 mice were divided into the normal group and the observation group,with 5 mice in each group.The mice in the observation group were injected with PKN1 adenovirus in situ in the heart,while the mice in the normal group were injected with empty adenovirus in situ in the heart.The Ki-67 positive expression in myocardial cells and tissues of mice in the four groups was detected by immunofluorescence assay,indicating the proliferation ability of cardiomyocytes.The PKN1 mRNA expression in cardiomyocytes of mice in the control group and interference group was measured by real-time fluorescence quantitative polymerase chain reaction.The expression of PKN1 and cyclin D1 proteins in cardiomyocytes of mice in the control group and interference group was determined by Western blot.Results The positive expression rates of Ki-67 in myocardial cells of mice in the interference group was significantly lower than that in the control group(t=11.201,P<0.01);the positive expression rate of Ki-67 in myocardial tissue of mice in the observation group was significantly lower than that in the normal group(t=11.851,P<0.01).The relative expression level of PKN1 mRNA in cardiomyocytes of mice in the interference group was significantly lower than that in the control group(t=7.022,P<0.01).The relative expression levels of PKN1 and cyclin D1 proteins in cardiomyocytes of mice in the interference group were significantly lower than those in the control group(t=5.762,6.884;P<0.01).Conclusion The decreased expression of PKN1 in mouse cardiomyocytes can inhibit the expression of cyclin D1 protein,thereby restraining cardiomyocyte proliferation.