miR-223-3p靶向调控MMP16对成纤维细胞功能的影响OACSTPCD

Objective To investigate the regulatory mechanism of myocardial fibrosis induced by miR-223-3p after cardiac injury in neonatal SD rats.Methods Neonatal SD rats aged 1-2 d were divided into model group and sham group.After surgical exposure of the heart,5%of the apical tissue of the heart was destroyed to achieve the effect of cardiac injury in model group,while no cardiac tissue was destroyed in sham group.The difference of miR-223-3p expression between the two groups was detected by miRNAs high-throughput chip at day 7 after surgery.The myocardium of neonatal SD rats aged 1-2 d was extracted,primary cardiomyocytes and cardiac fibro-blasts were isolated and cultured,and the difference of miR-223-3p expression was detected by RT-qPCR.Cardiac fibroblasts were randomized into four groups:miR-223-3p mimics group,mimics negative control(NC)group,miR-223-3p inhibitor group,and inhibitor NC group.The target genes of miR-223-3p,MMP16 and MEF2C,were predicted through biological website.RT-qPCR was used to detect the expressions of MMP16,MEF2C,and Collagen Ⅰand Ⅲ genes.Western blot was used to detect the expressions of MMP16 protein,Collagen Ⅰ and Ⅲ proteins.Immunofluorescence detection was used to detect Vimentin,α-smooth muscle actin(α-SMA)expression.In order to verify the target-regulatory relationship between miR-223-3p and MMP16,293T cells were cultured and divided into three groups:psiCheck2+rno-miR-223-3p mimics group,psiCheck2-MMP16-Wt+rno-miR-223-3p mimics group,and psiCheck2-MMP16-Mut+rno-miR-223-3p mimics group,and the expression of MMP16 activity was detected using dual luciferase reagent.Results Compared with sham group,the expression of miR-223-3p was increased in model group(P<0.05).Compared with primary cardiomyocytes,the expression of miR-223-3p was elevated in cardiac fibroblasts(P<0.001).Compared with mimics NC group,the expressions of MMP16 gene and protein were decreased in miR-223-3p mimics group(P<0.001),the expression of MEF2C gene was not statistically significant(P>0.05),the expressions of Collagen Ⅰ gene and protein were increased(P<0.01),the ex-pressions of Collagen Ⅲ gene and protein were decreased(P<0.05),the expression of Vimentin protein was increased while the ex-pression of α-SMA protein showed no obvious change.Compared with inhibitor NC group,the expressions of MMP16 gene and protein were increased in miR-223-3p inhibitor group(P<0.05),the expression of MEF2C gene was not statistically significant(P>0.05),the expressions of Collagen Ⅰ gene and protein were decreased(P<0.05),the expression of Collagen Ⅲ gene was increased(P<0.001),the expression of Collagen Ⅲ protein was not statistically significant(P>0.05),the expression of Vimentin protein was decreased and the expression of α-SMA protein showed no obvious change.Compared with psiCheck2-MMP16-Wt+rno-miR-223-3p mimics group,the activity of MMP16 was elevated in both psiCheck2+rno-miR-223-3p mimics group and psiCheck2-MMP16-Mut+rno-miR-223-3p mimics group(P<0.01).Conclusion miR-223-3p could promote the fibroblast proliferation and contribute to myocardial fibrosis by regulating the expression of the target gene MMP16.miR-223-3p may serve as a crucial regulatory gene for myocardial fibrosis after cardiac injury in rats.