Sinomenine induces apoptosis of human rheumatoid arthritis fibroblast-like synoviocytes via miR-23b-3p/FGF9 signaling pathway

AIM To investigate the effect of sinomenine （SIN） on the apoptosis of human rheumatoid arthritis （RA） fibroblast-like synoviocytes （FLS） and its molecular mechanism. METHODS Human RA FLS were isolated and cultured. The cells treated with lipopolysaccharide （LPS） at 100 mg/L was recorded as LPS group. The cells treated with SIN at 3.2 mmol/L and LPS at 100 mg/L were recorded as LPS+SIN group. The cells without any treatment served as blank group. The cells transfected with miR-con， miR-23b-3p， si-con and si-fibroblast growth factor 9 （FGF9） and treated with 100 mg/L LPS were recorded as LPS+miR-con group， LPS+miR-23b-3p group， LPS+si-con group and LPS+si-FGF9 group， respectively. The anti-miR-con， anti-miR-23b-3p， pcDNA and pcDNA-FGF9 were also transfected into RA FLS， and then the cells were treated with SIN at 3.2 mmol/L and LPS at 100 μg/mL. These cells were recorded as LPS+SIN+anti-miR-con group， LPS+SIN+anti-miR-23b-3p group， LPS+SIN+pcDNA group， LPS+SIN+pcDNA-FGF9 group， respectively. The cell viability was measured by CCK-8 assay. The number of colonies was accessed by colony formation experiment. The protein levels of FGF9， cleaved caspase-3， Bax and Bcl-2 were determined by Western blot. The apoptosis was analyzed by flow cytometry. The expression of miR-23b-3p and FGF9 mRNA was detected by RT-qPCR. Dual-luciferase reporter assay was used to verify the targeting relationship between miR-23b-3p and FGF9. RESULTS Treatment with SIN promoted LPS-induced apoptosis of RA FLS， inhibited cell proliferation， up-regulated miR-23b-3p expression， and down-regulated FGF9 expression. miR-23b-3p targeted FGF9. Over-expression of miR-23b-3p or silencing of FGF9 inhibited LPS-induced proliferation and enhanced apoptosis of the RA FLS. Interfering with miR-23b-3p or over-expression of FGF9 reversed the effects of SIN on the proliferation and apoptosis of LPS-induced RA FLS. CONCLUSION Sinomenine induces RA FLS apoptosis and inhibits cell proliferation through miR-23b-3p/FGF9 signaling.