环状RNA circ_0120051通过miR-144-3p/IDH2轴抑制心肌成纤维细胞的纤维化表型研究OA北大核心CSTPCD

[Objective]To investigate the regulatory effect of circular RNA circ_0120051 on the fibrotic phenotype of cardiac fibroblasts and the potential mechanism involved.[Methods]The expression of circ_0120051 and its host gene of solute carrier family 8 member A1(SLC8A1)mRNA in the myocardium of healthy organ donors(n=24)and heart failure(HF)patients(n=21)were assessed by real-time quantitative polymerase chain reaction(RT-qPCR)assay.RNA stabili-ty of circ_0120051 was identified by RNase R exonuclease digestion assay.The cytoplasmic and nuclear distribution of circ_0120051 in human cardiomyocyte AC16 was detected by RT-qPCR assay.The expression of fibrosis-related genes in mouse cardiac fibroblasts(mCFs)with adenovirus-mediated overexpression of circ_0120051 was detected by RT-qPCR and Western blot assay,respectively.The effect of overexpression of circ_0120051 on the migration activity of mCFs was evaluated by wound-healing assay.RNA co-immunoprecipitation(RIP)was conducted to detect the interaction between circ_0120051 and miR-144-3p.The binding site of miR-144-3p in the 3'-UTR of isocitrate dehydrogenase 2(Idh2)mRNA was identified by the dual luciferase reporter gene assay.[Results]Circ_0120051 was significantly up-regulated in the myocardium of HF patients,while the mRNA expression of its host gene SLC8A1 was not changed.Circ_0120051 was mainly located in the cytoplasm of human AC16 cells.Results of RNase R exonuclease digestion revealed that circ_0120051 possesses the characteristic stability of circular RNA compared to the linear SLC8A1 mRNA.Overexpression of circ_0120051 could inhibit the expression of fibrosis-related gene in mCFs and mCFs migration.RIP assay confirmed the specific interaction between circ_0120051 and miR-144-3p.Transfection of miR-144-3p mimic could efficiently promote the expression of fibrosis-related genes in mCFs and reverse the inhibitory effect of circ_0120051 on the fibrotic phenotype of mCFs.Results of the dual luciferase reporter gene assay confirmed the interaction between miR-144-3p and the 3'-UTR of Idh2.Transfection of miR-144-3p transcriptionally inhibited Idh2 expression,and overexpression of circ_0120051 enhanced IDH2 expression in mCFs.MiR-144-3p mimic and Idh2 small interfering RNA(siRNA)could consis-tently reverse the inhibitory effects of circ_0120051 on fibrosis-related genes expression in mCFs and mCFs migration.[Conclusions]Circ_0120051 inhibits the fibrotic phenotype of cardiac fibroblasts via sponging miR-144-3p to enhance the target gene of IDH2 expression.