Integrin β1 in osteoblast differentiation and migration during acute bone loss after fracture: Regulation of extracellular signal-regulated kinase 1/2 signaling pathway.

OBJECTIVE: Integrin β1 (ITGB1) reportedly participates in osteoblast differentiation, mineralization, and migration. Nevertheless, its role and underlying mechanism in osteoblast differentiation and migration during acute bone loss after fracture are not yet clear. This research was designed to measure the role of ITGB1 in osteoblast differentiation and migration and the underlying mechanism. MATERIAL AND METHODS: ITGB1 expression was assessed in MC3T3-E1 cells at different incubation times (0, 4, 7, 14, 21, and 28 days) through quantitative real-time polymerase chain reaction. Alkaline phosphatase (ALP) activity determination, ALP staining, and Alizarin red staining were performed to evaluate the differentiation degree of osteoblasts. Western blot was performed to detect the expression of markers related to osteoblast differentiation. Osteoblast migration ability was determined by wound healing and transwell assays. The molecular mechanism by which ITGB1 modulated the differentiation and migration of osteoblasts was examined by Western blot. RESULTS: ITGB1 expression increased significantly after 14, 21, and 28 days of osteoblast differentiation. ITGB1 increases enhanced osteoblast differentiation and migration; conversely, reduced ITGB1 inhibits osteoblast differentiation and migration. Mechanically, ITGB1 facilitated the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway, and the suppression of the ERK ERK1/2 pathway attenuated the effects of ITGB1 on osteoblast differentiation and migration. CONCLUSION: ITGB1 plays an important role in osteoblast differentiation and migration by activating the ERK1/2 signaling pathway, which may provide novel insights into bone injury treatment.