Sonic Hedgehog promotes fibroblast-like synoviocytes proliferation via modulating the mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway in rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective To study the effect of mitogen-activated protein kinas/extracellular signalregulated kinase (MAPK/ERK) signaling pathway on cell proliferation modulated by Sonic Hedgehog (Shh) signaling in fibroblast-like synoviocytes (FLS) isolated from patients with active rheumatoid arthritis (RA).Methods The synovial tissue were collected by the synovial arthroscopic debridement or arthroscopic synovectomy of RA patients with active disease activity [disease activity score(DAS)28 ≥3.2].The RA-FLS were primarily cultured by the explanted culture,and then were treated with Shh agonist purmorphamine,inhibitor cyclopamine or MAPK/ERK signaling pathway inhibitor U0126,respectively.Western blotting was used to examine the phosphorylation level of ERK 1/2 (p-ERK1/2),which was the critical protein of MAPK/ERK signaling.The cell proliferation activity was detected using cell proliferation and cytotoxicity kit-8 (CCK8),and the cell proliferation rate was detected using a flow cytometry.Analysis of variance and Kruskal-Wallis H(K) test were used for statistical analysis.Results Compared with the control group,purmorphamine transiently increased p-ERK1/2 protein at the concentration of 1 μmol/L,and the peak activations of p-ERK1/2 took place at 15 min (P＜0.01).Cyclopamine and U0126 decreased the expression ofp-ERK1/2 protein (P＜0.01).After the RA-FLS treated with purmorphmine(1 μmol/L)for 48 hours,the cell proliferation activity was (114±4)％ and the percentage of S phase cells was (8.39±0.60)％,which was significantly higher than those of the control group (100±0)％ (P＜0.01) and (3.29±0.69)％ (P＜0.01).After treated with cyclopamine (10 μmol/L) for 48 hours,the cell proliferation activity of RA-FLS was (89±1)％ (P＜0.05) and the percentage of S phase cells was (1.53±0.22)％ (P＜0.05).When co-treated with purmorphamine (1 μmol/L) and U0126 (10 μmol/L),the cell proliferative activity was (89±2)％ (P＜0.05) and the percentage of S phase cells was(1.07±0.25)％(P＜ 0.05).Conclusion Shh may promote proliferation of RA-FLS via modulating MAPK/ERK signaling,which in turn contributes to hyperplasia of synovium and ultimately leading to RA.