The Study On The Effect Of LncRNA-LFAR1 On Myocardial Fibrosis And Related Molecular Mechanisms

Background and PurposeThe main feature of myocardial fibrosis is the excessive deposition of extracellular matrix(ECM),which leads to the loss of cardiac function by increasing the hardness of heart tissue,and finally leads to cardiac insufficiency,arrhythmia and heart failure(HF).Myocardial fibrosis is a key factor in the progression of various types of cardiovascular diseases and is significantly associated with adverse clinical outcomes.Studies have shown that as many as 3/4 of human genes in the genome are transcribed into non-coding RNA(ncRNA).These noncoding RNA transcripts can be divided into micro RNA(miRNA)and long noncoding RNA(LncRNA)and circular RNA(circ RNA).Recent studies have shown that LncRNA plays an important role in the occurrence and development of different diseases.LncRNA-LFAR1 is a newly discovered LncRNA,that can promote the occurrence and development of liver fibrosis,but its role in myocardial fibrosis and its related mechanism have not been reported.Therefore,the purpose of this study is to explore whether LncRNA-LFAR1 affects myocardial fibrosis and to explore the potential molecular mechanisms.Methods(1)In vivo,the myocardial fibrosis model was established by subcutaneous injection of isoproterenol in mice.The success of the model was verified by HE staining,Masson staining,quantitative real-time polymerase chain reaction(q RT-PCR)and western blot(WB).The expression of LncRNA-LFAR1 in myocardial fibrosis tissues was detected by q RT-PCR.(2)In vitro,we gave cardiac fibroblasts(CFs)with different concentrations of transforming growth factor-β1(TGF-β1),verified the success of the establishment of the cell fibrosis model by q RT-PCR and WB,selected the optimal dosage of TGF-β1,and detected the expression of LncRNA-LFAR1 in the fibrosis model by q RT-PCR.(3)In vitro,we synthesized small interfering RNA(si RNA)of LncRNA-LFAR1,and silenced LncRNA-LFAR1 using si RNA transfection technology.The effect of silencing LncRNA-LFAR1 on the proliferation and migration of CFs was detected by 5-ethynyl-2’-deoxyuridine(Ed U)staining and cell scratch assay.Immunofluorescence of α-smooth muscle actin(α-SMA)cells was used to evaluate the effect of silenced LncRNA-LFAR1 on TGF-β1 induced transformation of CFs into myofibroblasts,and qRT-PCR and WB were used to detect the expression of fibrosis related m RNA and protein.(4)Predict the downstream target genes that may be bound by LncRNA-LFAR1 and verify the expression of interaction target genes by q RT-PCR.(5)In vitro,LncRNA-LFAR1 si RNA and miR-186-5p inhibitor were transfected at the same time to explore whether LncRNA-LFAR1 promoted myocardial fibrosis through sponge miR-186-5p.Results(1)In the myocardial fibrosis model induced by ISO,the number of cardiomyocytes was significantly decreased,the arrangement was disordered,the inflammatory cell infiltration,cell edema and myocardial interstitial fibrosis were significantly increased;the expression of α-SMA and collagen Ⅰ(Col 1α1)in myocardial tissue of ISO group was significantly higher than that of control group,and the expression of LncRNA-LFAR1 in myocardial tissue of ISO group was significantly up-regulated.(2)In CFs induced by TGF-β1,the expression of α-SMA and Col 1α1 was significantly increased,and LncRNA-LFAR1 was significantly up-regulated,and the most significant change was found in TGF-β1 at the concentration of 20ng/ml.(3)After silencing LncRNA-LFAR1,the proliferation,migration and transformation into myofibroblasts of CFs were significantly inhibited,while the expression of α-SMA and Col 1α1 decreased.(4)After silencing LncRNA-LFAR1,the expression of miR-186-5p in CFs increased.(5)The expression of α-SMA and Col 1α1 in CFs transfected with LncRNA-LFAR1 si RNA and miR-186-5p inhibitor was higher than that in LncRNA-LFAR1 siRNA group.ConclusionsLncRNA-LFAR1 can promote myocardial fibrosis.The underlying mechanism may be that LncRNA-LFAR1 promotes the transformation,proliferation,migration and fibrin expression of CFs through sponge miR-186-5p.Therefore,LncRNA-LFAR1 can be used as a potential new target for the prevention or treatment of myocardial fibrosis.These findings provide new ideas for in-depth understanding of the role of LncRNA in myocardial fibrosis and related mechanisms.