MiR-199a-3p inhibits proliferation and induces apoptosis in rheumatoid arthritis fibroblast-like synoviocytes via suppressing retinoblastoma 1.

Background Fibroblast-like synoviocytes (FLSs) that line the intimal synovium play a crucial role in the pathogenesis of rheumatoid arthritis (RA). miR-199a-3p is a highly conserved miRNA that has been shown to regulate a variety of growth behaviors in diverse cell types. However, the role of miR-199a-3p in RA-FLS is still unknown. Methods Here, we presented the first experimental evidence showing that miR-199a-3p was a critical regulator of RA-FLS function. Results miR-199a-3p expression was significantly reduced in RA-FLS compared with normal FLS. Ectopic expression of miR-199a-3p significantly inhibited RA-FLS proliferation and induced apoptosis, which was demonstrated by an increase in caspase-3 activity and Bax/Bcl-2 ratio. Our bioinformatics analysis identified Retinoblastoma 1 (RB1) gene to be a direct target of miR-199a-3p. In RA-FLS, miR-199a-3p directly targetted the 3'-UTR of RB1 mRNA and suppressed endogenous RB1 expression, whereas miR-199a-3p-resistant variant of RB1 was not affected. Silencing RB1 decreased cell proliferation and promoted apoptosis in RA-FLS, an effect comparable with miR-199a-3p overexpression. Enforced expression of RB1 partially restored cell proliferation and attenuated apoptosis in miR-199a-3p-overexpressing RA-FLSs. Conclusion In summary, miR-199a-3p is down-regulated in RA-FLS, and miR-199a-3p inhibits proliferation and induces apoptosis in RA-FLS, partially via targetting RB1. The miR-199a-3p/RB1 pathway may represent a new therapeutic target for RA.

Wangyang Y ，Yi L ，Wang T ，Feng Y ，Liu G ，Li D ，Zheng X ... -  《-》

MicroRNA-192 suppresses cell proliferation and induces apoptosis in human rheumatoid arthritis fibroblast-like synoviocytes by downregulating caveolin 1.

Li S ，Jin Z ，Lu X 《-》

MiR-26a-5p enhances cells proliferation, invasion, and apoptosis resistance of fibroblast-like synoviocytes in rheumatoid arthritis by regulating PTEN/PI3K/AKT pathway.

Behavior alterations in fibroblast-like synoviocytes (FLS) contribute to a pivotal role in pathogenesis of rheumatoid arthritis (RA). MiRNAs are closely involved in a variety of pathologic conditions. In the present study, we aimed to screen for the aberrant expression of miRNAs in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) to further identify the altered expression of miR-26a-5p in RA-FLS and to investigate the role of miR-26a-5p in RA. The altered expression of miR-26a-5p in RA-FLS was screened by microarray analysis and confirmed by quantitative real time PCR. The effect of miR-26a-5p on proliferation, cell cycle, apoptosis, and invasion in RA-FLS were studied. The verification of miR-26a-5p target mRNA and downstream signaling pathway was elucidated by bioinformatics analysis, dual luciferase reporter assay, and western blot. Expression of miR-26a-5p was higher in RA-FLS than in fibroblast-like synoviocytes from osteoarthritis patients and trauma patients. Overexpression of miR-26a-5p RA-FLS promoted cells proliferation, G1/S transition, cells invasion, and resisted apoptosis in RA-FLS, whereas it led to contrary effects when inhibiting the expression of miR-26a-5p. The 3'UTR of tensin homolog (PTEN) was directly targetted by miR-26a-5p and activation of phosphoinositide 3-kinase (PI3K)/AKT pathway was observed when overexpression of miR-26a-5p. Our study suggested that miR-26a-5p has a complementary role in cells proliferation, invasion, and apoptosis of RA-FLS, which may be attributed to its activation effect on PI3K/AKT signaling pathway via targetting PTEN. MiR-26a-5p is likely to be a clinically helpful target for novel therapeutic strategies in RA.

Huang Z ，Xing S ，Liu M ，Deng W ，Wang Y ，Huang Z ，Huang Y ，Huang X ，Wu C ，Guo X ，Pan X ，Jiang J ，Feng F ，Li T ... -  《-》

miR-410-3p regulates proliferation and apoptosis of fibroblast-like synoviocytes by targeting YY1 in rheumatoid arthritis.

In our previous study, miR-410-3p had been confirmed to regulate inflammatory cytokine release in rheumatoid arthritis fibroblast-like synoviocytes (RA FLSs). However, other biological functions of miR-410-3p in RA FLSs still remain unexplored. In the present study, we focused on the effect of miR-410-3p on proliferation, apoptosis, and cell cycle of RA FLSs, and explored the potential underlying mechanism. miR-410-3p mRNA levels in the synovium and FLSs of patients with RA and of healthy controls were quantitated by RT-qPCR. The levels of miR-410-3p were reduced in both synovium and FLSs from patients with RA. Next, we focused on the roles of miR-410-3p in cell viability, apoptosis, and cell cycle, by transfecting miR-410-3p mimics and inhibitor into RA FLSs, and conducting CCK-8 assay, EdU staining and flow cytometry. Results showed that miR-410-3p up-regulation suppressed proliferation, promoted apoptosis and G1-S phase transition while miR-410-3p down-regulation had opposite effects. YY1 was verified as a direct target gene of miR-410-3p through the luciferase reporter system; YY1 up-regulation was able to rescue the effects of miR-410-3p in RA FLSs. Taken together, our current findings might provide a potential therapeutic target for RA.

Wang Y ，Jiao T ，Fu W ，Zhao S ，Yang L ，Xu N ，Zhang N ... -  《-》

LncRNA NEAT1 Targets Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via the miR-410-3p/YY1 Axis.

LncRNA NEAT1 functions as an oncogene in multiple human cancers. However, its expression and role in fibroblast-like synoviocytes (FLSs) from patients with rheumatoid arthritis (RA) remain unclear. Thus, we investigated the expression of NEAT1 in synovial tissues and FLSs in RA, to determine its role in the development of RA. Quantitative real-time polymerase chain reaction was used to measure the expression of NEAT1. FLS proliferation was evaluated using cell proliferation assays. Flow cytometry was used to analyze cell cycle progression and apoptosis in FLSs. Binding between NEAT1 and miR-410-3p was demonstrated by dual-luciferase assays. We found that NEAT1 was upregulated in synovial tissues and FLSs in RA. Upregulation of NEAT1 promoted cell proliferation, induced S-to G2/M phase transition, and suppressed apoptosis in RA FLSs. NEAT1 directly bound to and negatively modulated miR-410-3p expression, while positively regulating YinYang 1(YY1; a miR-410-3p target). Inhibiting miR-410-3p and upregulating YY1 partially restored the inhibitory role in cell viability induced by the depletion of NEAT1 in RA FLSs. Besides pro-proliferative and anti-apoptotic roles, upregulation of NEAT1 promoted migration, invasion, and inflammatory cytokines secretion in RA FLSs. Taken together, our results suggest that the NEAT1 may serve as a novel diagnostic and therapeutic target for patients with RA.

Wang Y ，Hou L ，Yuan X ，Xu N ，Zhao S ，Yang L ，Zhang N ... -  《Frontiers in Immunology》