IL-1β REGULATES CELLULAR PROLIFERATION, PROSTAGLANDIN E2 SYNTHESIS, PLASMINOGEN ACTIVATOR ACTIVITY, OSTEOCALCIN PRODUCTION, AND BONE RESORPTIVE ACTIVITY OF THE MOUSE CALVARIAL BONE CELLS

Abstract

ABSTRACTInterleukin-1β (IL-1β) regulates several activities of the osteoblast cells derived from mouse calvarial bone explants in vitro. IL-1β stimulated cellular proliferation and the synthesis of prostaglandin E2 in the cultured cells in a dose-dependent manner. Furthermore, plasminogen activator activity of the mouse osteoblast was positively affected by IL-1β in a dose-dependent manner over the dosage range of 0.01 ng−2 ng/mL with a maximal effect being observed at 2 ng/mL. However, the induction of osteocalcin synthesis and alkaline phosphatase activity in response to vitamin D, two characteristics of the osteoblast phenotype, were significantly antagonized by IL-1β over a similar dose range.Treatment of mouse calvarial bone cells with IL-1β resulted in a dose dependent stimulation of bone resorption and the bone resorption induced by IL-1β was strongly inhibited by calcitonin treatment, indicating osteoclast-mediated bone resorption, suggesting that the bone resorption induced by IL-1β appears to be osteoclast-mediated. This study supports the role of IL-1β in the pathological modulation of bone cell metabolism, with regard to implication of the pathogenesis of osteoporosis by IL-1β.