Mechanosensitive TRP channels in osteoblasts

Mechanical stress plays a vital role in maintaining bone architecture. The process by which osteoblasts convert mechanical signal into biochemical responses leading to bone remodeling is not fully understood. The earliest cellular response detected in mechanically stimulated osteoblasts is an increase in intracellular calcium concentration ([Ca2+](i)). This increase in [Ca2+](i) results from Ca2+ influx from the extracellular space via calcium channels located on the plasma membrane. In spite of the significant role of calcium channels in osteoblast, the molecular identity of mechanosensitive channels remains unknown. However, in recent study, the expression patterns of mammalian homologues of Drosophira transient receptor potential (TRP) channel superfamily in the clonal osteoblastic cell lines were investigated. RT-PCR analysis revealed that some mechanosensitive TRP channel genes are expressed in osteoblastic cells. This chapter attempts to provide an overview of the current knowledge on mechanosensitive TRP proteins and discuss their possible roles in osteoblastic cells.