鸟苷酸交换因子C3G对心肌细胞生存力的影响及其可能机制

目的 探讨过表达鸟苷酸交换因子C3G(Crk SH3-domain-binding guanine-nucleotide-releasing factor)对心肌细胞生存力的影响及其机制.方法 分别用pCXN2-Flag、pCXN2-Flag-hC3G(过表达人C3G mRNA)质粒瞬时转染H9C2心肌细胞,并进行缺氧/复氧(H/R)于预.实验分为空白组、空质粒组、C3G过表达组、空白+H/R组、空质粒+H/R组,C3G过表达+H/R组.用RT-PCR法检测心肌细胞C3G mRNA的表达,蛋白质印迹分析法检测心肌细胞C3G、p-ERK1/2蛋白的表达,MTT法检测细胞的增殖率,流式细胞术检测细胞的凋亡率.结果 C3G过表达组较空白组和空质粒组,C3G过表达+H/R组较空白+H/R组和空质粒+H/R组人C3G mRNA、C3G蛋白、p-ERK1蛋白、细胞增殖率均增加(P均＜0.01),凋亡率均降低(P＜0.05,P＜0.01);C3G过表达+H/R组较空白+H/R组、空质粒+H/R组p-ERK2蛋白增加(P＜0.01).结论 过表达C3G能促进心肌细胞的生存力,该过程可能是由p-ERK1/2蛋白表达增加和心肌细胞凋亡降低介导的.

Effect of guanine nucleotide exchange factor C3G overexpression on survival of cardiomyocytes and its underlying mechanisms

Objective To investigate the effects of the guanine nucleotide exchange factor C3G (Crk SH3-domain-binding guanine-nucleotide-releasing factor) overexpression on the survival of cardiomyocytes and the underlying mechanisms.Methods H9C2 cardiomyocytes were transiently transfected with pCXN2-Flag or pCXN2-Flag-hC3G (overexpressing human C3G mRNA) plasmids, and then were exposed to hypoxia/reoxygenation (H/R) treatment. The cardiomyocytes were divided into blank group, empty plasmid group, C3G overexpression group, blank+H/R group, empty plasmid+H/R group, and C3G overexpression+H/R group. The expression of C3G mRNA was detected by RT-PCR, and the expression of C3G and p-ERK1/2 protein was detected by Western blotting analysis. The apoptosis rates of cardiomyocytes were analyzed by flow cytometry in each group, and the cell proliferation rates were analyzed by MTT.Results C3G overexpression increased cell proliferation rate and expression of C3G mRNA and protein, p-ERK1 protein(all P<0.01), and decreased apoptosis rate (P<0.05,P<0.01) compared to the blank and empty plasmid groups; the same was true for C3G overexpression+H/R group when compared to the blank+H/R and empty plasmid+H/R groups. Expression of p-ERK2 protein in C3G overexpression+H/R group was increased compared to blank+H/R and empty plasmid+H/R groups (P<0.01).Conclusion C3G overexpression can promote cell survival in the cardiomyocytes, which might be mediated by the increase of p-ERK1/2 protein expression and apoptosis inhibition.