MiR-140-3p inhibits the cell viability and promotes apoptosis of synovial fibroblasts in rheumatoid arthritis through targeting sirtuin 3

Beibei Zu,Junxia Yang,Lin Liu,Jingya Wang,Meirong Li

doi:10.1186/s13018-021-02236-5

Abstract

BackgroundSynovial fibroblasts (SFs) with the abnormal expressions of miRNAs are the key regulator in rheumatoid arthritis (RA). Low-expressed miR-140-3p was found in RA tissues. Therefore, we attempted to investigate the effect of miR-140-3p on SFs of RA.MethodsRA and normal synovial fibrous tissue were gathered. The targets of miR-140-3p were found by bioinformatics and luciferase analysis. Correlation between the expressions of miR-140-3p with sirtuin 3 (SIRT3) was analyzed by Pearson correlation analysis. After transfection, cell viability and apoptosis were detected by cell counting kit-8 and flow cytometry. The expressions of miR-140-3p, SIRT3, Ki67, Bcl-2, Bax, and cleaved Caspase-3 were detected by RT-qPCR or western blot.ResultsLow expression of miR-140-3p and high expression of SIRT3 were found in RA synovial fibrous tissues. SIRT3 was a target of miR-140-3p. SIRT3 expression was negatively correlated to the expression of miR-140-3p. MiR-140-3p mimic inhibited the MH7A cell viability and the expressions of SIRT3, Ki67, and Bcl-2 and promoted the cell apoptosis and the expressions of Bax and cleaved Caspase-3; miR-140-3p inhibitor showed an opposite effect to miR-140-3p mimic on MH7A cells. SIRT3 overexpression not only promoted the cell viability and inhibited cell apoptosis of MH7A cells but also reversed the effect of miR-140-3p mimic had on MH7A cells.ConclusionsThe results in this study revealed that miR-140-3p could inhibit cell viability and promote apoptosis of SFs in RA through targeting SIRT3.

Highlights

Synovial fibroblasts (SFs) with the abnormal expressions of miRNAs are the key regulator in rheumatoid arthritis (RA)
MiR-140-3p was low-expressed in RA synovial fibrous tissues and targeted sirtuin 3 (SIRT3) and SIRT1 We first detected the expression level of miR-140-3p in RA synovial fibrous tissues (RASFs) and normal synovial fibrous tissues (NSFs), as shown in Fig. 1a, the expression of miR-140-3p was significantly lower in RASFs than that in NSFs (P < 0.01)
Luciferase activity was decreased after 293T cells were transfected miR-140-3p mimic with SIRT3-WT or SIRT1WT together as compared to the control groups (P < 0.001, P < 0.01, respectively), while after being cotransfected miR-140-3p mimic with SIRT3-MUT or SIRT1-MUT there was no difference in the luciferase activities as compared to the mimic control groups (Fig. 1c, f)

Summary

Introduction

Synovial fibroblasts (SFs) with the abnormal expressions of miRNAs are the key regulator in rheumatoid arthritis (RA). Low-expressed miR-650 was found in SFs of RA patients than that in normal cells, and miR-650 inhibited the proliferation and invasion of SFs by regulating AKT2 [11]. Expression level of miR-613 was downregulated in RA tissues and SFs than that in normal tissues and cells; it could suppress the proliferation and induce apoptosis of SFs by targeting DDK1 [8]. Study reported that in tissues of AR patients and mice, the expressions of miR140-5p and miR-140-3p were significantly downregulated [7]; in addition, miR-140-5p overexpression was proved that it had the ability to inhibit SFs proliferation and induce apoptosis through regulating TLR4 [4, 7]. The effects and mechanisms of miR-140-3p on the apoptosis of SFs remained to be further investigated

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