Whitney A. Bullock

This chapter considers the types of cells and forces likely to impact bone formation/remodeling. It examines the cellular and molecular mechanisms regulating the biological responses of cells to those forces. Cells within bone detect, coordinate, and mediate mechanical loading on the skeleton. The cells most likely to function as the “mechanosensors” in bone are the osteocytes. Chemotransport also affects the response of bone cells to fluid flow independent of mechanical signal transduction. Bone cell mechanoreceptors can be classified into broad categories: integrins; G‐protein coupled receptors/receptor tyrosine kinases; and ion channels/connexin hemichannels. Ion channels sensitive to mechanical stimulation are also found in osteoblastic cells. Detection of a molecular response to mechanical stimulation does not prove that it is important for mechanotransduction in bone. The Wnt pathway has been identified as one of the most important mediators of bone cell mechanotransduction.