Irisin promotes cementoblast differentiation via p38 MAPK pathway

Objective Irisin is a newly identified exercise-induced myokine which can affect glucose metabolism and cortical bone mass and strength. However, the influence of irisin on cementoblasts remains largely unknown. Material and methods An immortalized mouse cementoblast cell line OCCM-30 was used in this study. Cementoblast differentiation markers and PGC-1 alpha in cells cultured with mineral induction medium were evaluated by qRT-PCR. Cementoblast mineralization was evaluated by alizarin red staining. Differentiation markers and the activity of p38 MAPK pathway under irisin stimulation were assessed by qRT-PCR or Western blot analysis. p38 MAPK pathway inhibitor SB203580 or p38 siRNA was used to further identify the regulatory mechanism. Cell proliferation treated with irisin was examined by CCK-8 method. Results The expression of Runx2, osterix, ALP, and PGC-1 alpha was up-regulated consistently under mineral induction. The formation of mineralized nodules was increased by irisin. Runx2, osterix, ALP, and osteocalcin were obviously up-regulated under irisin stimulation as well as the activity of p38 MAPK pathway. When pretreated with SB203580 or p38 siRNA before irisin stimulation, the irisin-induced differentiation was distinctly suppressed. OCCM-30 cell proliferation was enhanced when treated with high-dose irisin for long time. Conclusion Irisin can promote the differentiation of cementoblasts via p38 MAPK pathway.