This study aims to explore the regulatory effect of microRNA-193a-3p on rheumatoid arthritis (RA) and its underlying mechanism.
Expression level of microRNA-193a-3p in synovial tissues extracted from 30 RA patients and healthy controls was detected by quantitative Real-time polymerase chain reaction (qRT-PCR). MH7A cells were subjected to TNF-α induction for constructing the in vitro RA model. After transfection of microRNA-193a-3p inhibitor in MH7A cells, proliferation and apoptosis were detected by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Enzyme-linked immunosorbent assay (ELISA) was conducted to determine levels of interleukin 6 (IL-6) and IL-8 in MH7A cells. Subsequently, the dual-luciferase reporter gene assay was carried out to verify the binding condition between microRNA-193a-3p and IGFBP5. Rescue experiments were conducted to evaluate the proliferation and apoptosis of MH7A cells with knockdown of microRNA-193a-3p and IGFBP5.
MicroRNA-193a-3p was highly expressed in synovial tissues of RA patients and TNF-α-induced MH7A cells than those of controls. TNF-α induction significantly increased the proliferative rate of MH7A cells, reaching the peak at 96 h. After knockdown of microRNA-193a-3p, the promoted proliferation by TNF-α induction was significantly inhibited. In addition, TNF-α induction significantly inhibited the apoptosis of MH7A cells. After inhibition of microRNA-193a-3p expression, the inhibited apoptosis by TNF-α induction remarkably increased. TNF-α induction upregulated levels of IL-6 and IL-8 in MH7A cells, which were remarkably reduced after the microRNA-193a-3p knockdown. Dual-luciferase reporter gene assay confirmed that IGFBP5 could bind to microRNA-193a-3p, and its expression was negatively regulated by microRNA-193a-3p. The regulatory effects of microRNA-193a-3p on proliferation and apoptosis of MH7A cells were reversed by IGFBP5 knockdown.
MicroRNA-193a-3p is highly expressed in the synovial tissues and cells of rheumatoid arthritis. MicroRNA-193a-3p participates in the process of rheumatoid arthritis by regulating the proliferation, apoptosis and inflammatory response of MH7A cells through targeting IGFBP5.