Irisin promotes cementoblast differentiation via p38 MAPK pathway

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.

An immortalized mouse cementoblast cell line OCCM-30 was used in this study. Cementoblast differentiation markers and PGC-1α 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.

The expression of Runx2, osterix, ALP, and PGC-1α 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.

Irisin can promote the differentiation of cementoblasts via p38 MAPK pathway.