The role of sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) in regulation of osteoclastic and osteoblastic cells.

The bioactive lipid molecules, sphingosine-1-phosphate (S1P) and lysophosphatidic acid LPA) have recently emerged as potentially highly significant physiological and pathophysiological regulators of bone cell biology. Since compromised signaling by these bioactive lipids has been implicated in the etiology of disorders such as inflammatory and autoimmune diseases, their role in bone biology can be a key influence in the coordination of the events underlying osteoimmunology. Both S1P and LPA have been shown to have receptor-mediated effects on osteoblastic cell proliferation and differentiation critical to bone formation and on osteoclastic cell action and regulation of bone resorption. This review of the recent studies on these processes provides insight into the potential role of S1P and LPA as autocrine and paracrine mediators of bone remodeling and their potential interaction with immune cells that have emerged as important players in skeletal biology.