肌细胞增强子2A基因突变对血管内皮细胞增殖的影响

Myocyte enhancer factor 2A gene regulate proliferation of endothelial cells

目的探讨肌细胞增强子（MEF）2A基因突变对血管内皮细胞增殖的影响。方法采用人脐静脉内皮细胞，分别转染pcDNA3．0-GFP质粒（对照组）、野生型MEF2A质粒（野生型组，WT组）、21碱基缺失MEF2A质粒（A21突变组，A21组）和MEF2A siRNA片段（siRNA组）。应用细胞免疫荧光法检测MEF2A蛋白定位，MTT法测定内皮细胞增殖情况。结果绿色荧光蛋白结果与Flag抗体检测显示MEF2A基因成功转染，内皮细胞转染效率可达70％。与WT组比较，△21组MEF2A突变蛋白表达水平无显著变化，但其定位由核内转变为胞浆，siRNA组则使MEF2A蛋白表达下降80％。与WT组MEF2A转染相比，△21组和siRNA组脐静脉内皮细胞增殖率均显著下降（36．2％和63．6％，均为P〈0．01）。结论MEF2A基因可调节内皮细胞的增殖，其作用机制可能与MEF2A在细胞核内的定位相关。

Objective To investigate the effect of mutation of MEF2A on endothelial＇s proliferation. Methods Human umbilical vein endothelial cells （HUVECs） were transfected with one of the following plasmids： pcDNA-GFP plasmid （the control group）, MEF2A wild-type plasmid （WT group）, MEF2A 21-base pair deletion mutantion plasmid （△21 group）, and MEF2A siRNA （siRNA group）. Cell immunofluorescent assay was used to detect the location of the protein. HUVEC proliferation was analyzed by MTT. Results Transfection of MEF2A gene in HUVECs was detected by immunoblotting using anti-Flag antibody. The transfection efficiency of the HUVEC was approximately 70%. There was no significant difference in MEF2A protein expression between the wild-type and △21 mutation groups. SiRNA group has knockdown 80% of MEF2A protein expression compared with WT group. Immunofluorescence staining results showed that wild-type MEF2A protein was localized in the nucleus. The ATaa mutation of MEF2A protein in HUVECs could be detected in the cytoplasm. The proliferation of HUVEC was decreased in △21 （36. 2% , P 〈0. 01 ） and siRNA groups （63.6% , P 〈 0. 01 ） compared with that in the WT group. Conclusions Transfected MEF2A gene can regulate vascular endothelial cell proliferation. The shift of location of MEF2A protein may influence the process. The mechanism need to be further investigated.