In vitro and in vivo study on osteocyte-specific mechanical signaling pathways.

Mechanical loading of bone results in various osteogenic stimuli, including new bone formation as well as repair. In this process, osteocytes which are derived from osteoblasts are critical for communicating and sending signals to other bone cells through gap junctions with their dendritic processes to initiate bone remodeling. It is speculated that the history of weight bearing affects long-term cellular memory in the bone cell and osteocyte network that modulates the cellular response to a wide variety of stimuli. However, few markers for osteocytes are recognized and the gene expression patterns and pathways of osteocytes responding to mechanical loading are not well defined. To understand the mechanism of how cellular information is transmitted by mechanical loading in bone to the genome, we investigated load responsive gene expression patterns using the 2T3 osteoblast-osteocyte differentiation cell model, the MLO-Y4 osteocyte-like cell model and the mouse ulna loading model.