Osteopontin involvement in bone remodeling and its effects on in vivo osteogenic potential of bone marrow-derived osteoblasts/porous hydroxyapatite constructs

This review article will present our work regarding osteopontin (OPN) function in bone remodeling and its application to tissue engineering in bone. OPN, one of the major non-collagenous bone proteins, has an important role in bone remodeling. Our study suggested that OPN acts not only as a trigger for osteoblast early differentiation but activates osteoclast resorption. On this point of view, we proposed a model of bone remodeling via integrin αVβ3–OPN binding, in which OPN could act as a signal molecule between osteoblasts and osteoclasts in the process of remodeling. Moreover, OPN was shown to induce the in vivo osteogenesis of a bone marrow-derived osteoblast/porous hydroxyapatite (HA) constructs. Our application of adenovirus-mediated gene transfer of osteopontin to primary osteoblasts is also presented.