[Paeoniflorin inhibits Wnt1/β-catenin pathway and promotes apoptosis of fibroblast-like synoviocytes in patients with rheumatoid arthritis by upregulating lncRNA MALAT1].

Objective To explore the effect and mechanism of paeoniflorin (PAE) on apoptosis of fibroblast synovial cells derived from rheumatoid arthritis tissues. Methods Rheumatoid arthritis fibroblast-like synovial cells (RA-FLSs) were cultured under different concentrations of PAE (20, 40, 80 μmol/L). Survival rate of cells was determined at different incubation time-points (24, 48, 72 hours) by MTT assay. Flow cytometry was performed to determine apoptosis rate of cells. Cells were transfected with 3 small interfering RNAs(siRNAs) fragments of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1(lncRNA MALAT1) for 48 hours. Real-time quantitative PCR was performed to determine if MALAT1 knockdown was successful. Cells were assigned into control group, PAE group, si-NC group, si-MALAT1 group and PAE combined with si-MALAT1 group. Cell apoptosis rate was determined by flow cytometry after knockdown of MALAT1 expression. mRNA expression levels of Wnt1, β-catenin, caspase-3, caspase-9, B-cell lymphoma 2(Bcl2) and Bcl2-associated X protein (BAX) were determined using real-time quantitative PCR. Western blot analysis was performed to determine protein expression levels of Wnt1, β-catenin, caspase-3, caspase-9, Bcl2 and BAX in each group. Results The findings showed that incubation of RA-FLSs with PAE at the tested concentration decreased their viability in a time-dependent manner. Expression level of lncRNA MALAT1 was lower in RA-FLSs group compared with the level in NC-FLSs group. Analysis showed that apoptosis rate was higher in cells treated with PAE. si-MALAT1 group had the lowest apoptosis rate, whereas the PAE combined with si-MALAT1 group showed a significantly higher apoptosis rate compared with si-MALAT1 group. mRNA levels of Bcl2, Wnt1 and β-catenin were lower in PAE group compared with the level in control group, whereas mRNA expression levels of caspase-3, caspase-9 and BAX were higher in PAE group compared with the levels in control group. Expression level of Bcl2 was significantly higher in si-MALAT1 group compared with the level in the control group. Expression level of BAX, caspase-3 and caspase-9 were higher in PAE combined with si-MALAT1 group compared with the level in the control group. Conclusion PAE promotes apoptosis and inhibits the Wnt1/β-catenin pathway in RA-FLSs by upregulating expression of lncRNA MALAT1.