Mesenchymal Stem Cells Inhibit the Proliferation and Migration of Fibroblast-like Synoviocytes in Rheumatoid Arthritis via Exosome-mediated Delivery of miRNAs

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by aggressive and symmetrical polyarthritis. Fibroblast-Like Synoviocytes(FLSs)play a central role in the pathogenesis of RA. The abnormal expression of miRNAs in RA FLSs mediates RA joint inflammation，synovial hyperplasia，and tissue destruction; MSC-Exos-derived miRNAs are a potential RA treatment strategy. This study aimed to investigate the hUCMSC-Exos can deliver miRNA to RA FLSs and affect their biological properties. MethodsPrimary hUCMSCs were isolated and cultured by tissue adherence method，and surface markers were identified by flow cytometry. We used differential centrifugation combined with ultrafiltration to obtain hUCMSC-Exos and identify them；The primary RA FLSs were isolated and cultured by trypsin digestion，then surface markers were identified by flow cytometry. We labeled the RNA of hUCMSC-Exos. hUCMSC-Exos was co-cultured with RA FLSs then the dyed RA FLSs were observed with a fluorescence microscope. GV493 with siRNA target sequences that could knock down Ago2 transfected hUCMSCs. Real-time PCR and Westen blot analysis Ago2 levels in hUCMSCs and transfected hUCMSCs to determine knockdown efficiency. Lentivirus GV493 with the target with the highest knockdown efficiency to transfect hUCMSCs，named hUCMSC KD3-Ago2 . Then hUCMSC-Exos，hUCMSC KD3-Ago2 -Exos，hUCMSC NC -Exos were extracted by the differential centrifugal method combined ultrafiltration method，then were identified. The real-time cell analysis was used to detected the proliferation and migration of RA FLSs in different concentrations of hUCMSC-Exos. Finally，we used the optimal concentration of hUCMSC KD3-Ago2 -Exos and hUCMSC NC -Exos to intervene in RA FLSs. ResultsAfter incubation with hUCMSC-Exos and RA FLSs，the hUCMSC-Exos accumulated in the blue nuclei of RA FLSs. hUCMSC NC -Exos and hUCMSC KD-Ago2 -Exos inhibited the proliferation and migration of RA FLSs compared ，particularly the hUCMSCNC-Exos had the significant inhibitory effect. ConclusionshUCMSC-Exos RNA can be taken up by RA FLSs，and hUCMSC may affect the proliferation and migration of RA FLSs via exosome-mediated delivery of miRNA.