Modulatory Effect of 1,25-Dihydroxyvitamin D3on IL1β-Induced RANKL, OPG, TNFα, and IL-6 Expression in Human Rheumatoid Synoviocyte MH7A

摘要

Receptor activator of nuclear factorκB ligand (RANKL) plays a crucial role in the bone erosion of rheumatoid arthritis (RA) by prompting osteoclastogenesis. Considering that 1,25(OH)2D3has been suggested as a potent inducer of RANKL expression, it should clarify whether vitamin D supplement could result in RANKL overexpression and thereby facilitate excessive osteoclastogenesis and bone resorption in RA. Here, we investigated modulatory effect of 1,25(OH)2D3on the expression of RANKL and its decoy receptor osteoprotegerin (OPG) in an inflammatory condition of human rheumatoid synoviocyte MH7A. MH7A cells were stimulated with IL1βand then treated with different concentrations of 1,25(OH)2D3for 48 h. A significantly elevated OPG/RANKL ratio and markedly decreased levels of IL-6 and TNFβmRNA expression in cells and IL-6 protein in supernatants were observed in IL1β-induced MH7A in the presence of 1,25(OH)2D3compared with those in the absence of it. Osteoclast formation was obviously decreased when RAW264.7 cells were treated with both 1,25(OH)2D3and IL1β. In summary, although it has a biological function to induce RANKL expression, 1,25(OH)2D3could upregulate OPG/RANKL ratio and mediate anti-inflammatory action in an inflammatory milieu of synoviocyte, contributing to the inhibition of inflammation-induced osteoclastogenesis in RA.