Physiology of Mechanotransduction: How Do Muscle and Bone Talk'' to One Another?

The complexity of cell interactions with their microenvironment and their ability to communicate at the autocrine, paracrine, and endocrine levels has gradually but significantly evolved in the last three decades. The musculoskeletal system has been historically recognized to be governed by a relationship of proximity and function, chiefly dictated by mechanical forces and the work of gravity itself. In this review article, we first provide a historical overview of the biomechanical theory of bonemuscle interactions. Next, we expand to detail the significant evolution in our understanding of the function of bones and muscles as secretory organs. Then, we review and discuss new evidence in support of a biochemical interaction between these two tissues. We then propose that these two models of interaction are complementary and intertwined providing for a new frontier for the investigation of how bone-muscle cross talk could be fully explored for the targeting of new therapies for musculoskeletal diseases, particularly the twin conditions of aging, osteoporosis and sarcopenia. In the last section, we explore the bone- muscle cross talk in the context of their interactions with other tissues and the global impact of these multitissue interactions on chronic diseases.