DNA methyltransferase 3A regulates the expressions of collagens during the activation of cardiac fibroblasts / 医学研究生学报

ABSTRACT

Objective The mechanisms of methylation acting on myocardial fibrosis are not yet clear at present. The aim of this study was to investigate the role of DNA methyltransferase 3A (DNMT3A) in regulating the expressions of collagens during the activation of cardiac fibroblasts.Methods Cardiac fibroblasts were obtained from 50 neonatal mice and divided into three groups: blank control, DNMT3A overexpression plasmid (mDNMT3A-pEGFP-C3) and small interference DNMT3A siRNA. The contents of collagens in the cell supernatant were detected by ELISA. The mRNA and protein expressions of type I collagen (Col Ⅰ), type Ⅲ collagen (Col Ⅲ) and DNMT3A in the cardiac fibroblasts were determined by real-time quantitative PCR and Western blot respectively and the proliferative activity of the cardiac fibroblasts measured by CCK8 assay.Results The contents of Col I and Col Ⅲ in the cell supernatant were significantly increased in the DNMT3A overexpression plasmid group but decreased in the DNMT3A siRNA group as compared with those in the blank control (P<0.05). The expressions of Col Ⅰ, Col Ⅲ and DNMT3A were remarkably higher in the DNMT3A overexpression plasmid group but lower in the DNMT3A siRNA group than in the blank control (P<0.05). The cell activity was markedly higher in the DNMT3A overexpression plasmid group than in the empty vector plasmid and control groups (2.087±0.317 vs 1.063±0.223 and 1.082±0.207, P<0.05) but lower in the DNMT3A siRNA group (0.463±0.087) than in the latter two (P<0.05).Conclusion DNMT3A can increase the proliferation and activation of cardiac fibroblasts, upregulate the expressions of collagens and thus promote myocardial fibrosis.