Effects of Sonic Hedgehog pathway on apoptosis of endothelial cells / 中华风湿病学杂志

ABSTRACT

Objective To investigate Smoothened (Smo) expression in endothelial cells of synovial tissues in active rheumatoid arthritis (RA),and the expression of Sonic Hedgehog (Shh) signaling pathwayassociated factors after TNF-α treatment in EA.hy926 cells,and the effects of specific inhibitor of Smo (cyclopamine) on the apoptosis of EA.hy926 cells.Methods The Smo expression in endothelial cells in synovial tissue from 4 RA patients and 4 patients with traumatic or meniscal injury (with no arthritis,act as control group) were detected by immunohistochemistry assay.EA.hy926 cells were treated with different concentrations of TNF-α or TNF-α together with different concentrations of cyclopamine,and Shh,Ptch1,Smo,Gli1 mRNA expression levels were detected by real time-PCR.EA.hy926 cells were co-cultured with three different concentrations of cyclopamine for 24 hours before the addition of TNF-α and ActinomycinD (ActD).The cell survival rate was detected using CCK-8,and the population of apoptotic cells was detected using a flow cytometry.T-test and one-way ANOVA were used for statistical analysis.Results The positive expression rate of Smo in endothelial cells of synovial tissue in RA group was (81±23)％,which was higher than that in the control group (20±17)％ (P＜0.05).After being treated with TNF-α,the expressions of Shh and Smo mRNA in EA.hy926 cells increased,while the expression of Gli1 mRNA decreased (P＜0.05),and the expression of Ptch1 mRNA did not change significantly (P＞0.05).The expressions of Shh,Smo and Gli1 mRNA were down-regulated (P＜0.05).EA.hy926 cells treated with different concentrations of cyclopamine (2,4 and 8 μmol/L) showed a significant decrease in cell viability,in cell survival rates (57±6)％,(44±8)％ and (32±5)％ compared with that of TNF-α/ActD group (64±6)％ (P＜0.05),and cell apoptosis rates [(12.4±3.3)％,(14.5±2.7)％ (15.7±2.4)％] compared with that of TNF-α/ActD group (7.1±1.3)％ (P＜0.05).Conclusion Shh pathway is activated in endothelial cells of synovial tissue in active RA.The apoptosis in endothelial cells is promoted after cyclopamine treatment.Shh pathway may play an important role in the antiapoptotic regulatory mechanism of endothelial cells.