Periostin regulates osteogenesis of mesenchymal stem cells from ovariectomized rats through actions on the ILK/Akt/GSK-3β Axis.

Osteoporosis is a condition of the skeleton that mainly results from estrogen deficiency. Periostin is a matricellular component in bone that is involved in osteoblast differentiation. However, how Periostin promotes osteogenesis remains largely unknown. Here, we isolated bone marrow skeletal stem cells (BMSCs) derived from an ovariectomy (OVX)-induced osteoporosis rat model and the effects of periostin on BMSCs derived from OVX rats (OVX-BMSCs) were assessed. Overexpression of periostin enhanced alkaline phosphatase (ALP) and alizarin red staining in OVX-BMSCs as well as the osteogenic genes OCN, BSP and Runx2. ILK is a downstream effector of signals from the extracellular matrix and participates in bone homeostasis. Overexpression of periostin also increased expression of protein levels for ILK, as well as the downstream targets pAkt and pGSK3β. Suppression of ILK or Akt partially suppressed the enhancement of osteogenic ability induced by periostin overexpression in OVX-BMSCs. Thus, periostin may promote the osteogenic ability of OVX-BMSCs through actions on the ILK/Akt/GSK3β axis.