The Expression And Function Of MiR-145-5p In Rheumatoid Arthritis

Purpose Rheumatoid arthritis(RA)is a kind of autoimmune diseases in the world.RA usually diseased insidiously and the course of disease is long and painful.RA has individual differences in patients and is lack of effective cure of drugs.The deterioration of the disease often lead to joint deformity,or even disabled.At present,it is generally accepted that the pathogenesis of RA is a disorder of the immune system,which involves the abnormal expression of a variety of inflammatory cytokines in the synovium.A series of inflammatory reactions are mediated by these cytokines.Recent studies have found that some miRNA such as miR-146 a,miR-155,miR-181 a could be regulated by some inflammatory cytokines.At the same time,miRNAs can also affect the occurrence and development of RA by regulating the expression of some cytokines or targeting some immune related genes.At present,several miRNA was reported to have effect in RA,while the role of miR-145 in RA has rarely been studied.Previous research of miR-145 was mostly considered as a tumor suppressor,which could affect the development of tumor by regulating the target genes related to the malignant process of tumor.Therefore,this study takes miR-145-5p as research object to find out the regulation of miR-145-5p in RA.Methods In this study,the relative expression of miR-145-5p in PBMC cells of 20 RA patients were detected by quantitative PCR and the results were compared with the ordinary people.After transfecting the RA-FLS with miR-145-5p mimic and inhibitor for miR-145-5p overexpression and knockdown,we carried out cell proliferation,apoptosis,cell cycle and quantitative PCR experiments to study the effect of miR-145-5p on the cell phenotype.We also tested the effect of miR-145-5p overexpression on RA related inflammatory factor MMP9.Bioinformatics software and pathway analysis was used to find cell proliferation,cell cycle,apoptosis and bone metabolism pathway related genes of miR-145 targets.Q-PCR and Western blot were conducted to verify the candidate target genes at m RNA and protein levels in order to confirm the role of miR-145-5p in RA mechanism.Results1.The expression of miR-145-5p in PBMC cells of 20 RA patients and 20 normal persons were detected.Results showed that the expression of miR-145-5p in RA PBMC was significantly higher in than in normal PBMC.2.After overexpression of miR-145-5p,the proliferation ability of cells was significantly reduced.And after the reduction of miR-145-5p,the proliferation ability of cells was significantly increased.3.After overexpression of miR-145-5p,the number of cells in G2 phase was significantly reduced.After knocking down miR-145-5p,the number of cells in G2 phase increased significantly.4.The number of apoptotic cells in miR-145 overexpression sample was significantly higher than that of the control group and the number of apoptotic cells in miR-145 knockdown sample was significantly lower than that of the control group.5.Increased miR-145-5p level could decrease the expression of MMP9,suggesting that miR-145-5p could inhibit the development of inflammation by down regulating the expression of RA inflammatory factor.6.Informatics predicts that ADAM17 may be a target gene for miR-145-5p.Its m RNA and protein levels are down regulated after promoting miR-145-5p expression and downregulated after miR-145-5p knockdown.Conclusion The expression of miR-145-5p was increased in RA patients PBMC and decreased in RA-FLS.MiR-145-5p influences the proliferation,apoptosis and cell cycle progression of RA-FLS by targeting ADAM17,which in turn regulate TNF-?,cell proliferation pathway and inflammatory factor MMP9 expression to influence synovial inflammation.