Crosstalk between bone and other organs

Abstract

Bone has long been considered as a silent organ that provides a reservoir of calcium and phosphorus, traditionally. Recently, further study of bone has revealed additional functions as an endocrine organ connecting systemic organs of the whole body. Communication between bone and other organs participates in most physiological and pathological events and is responsible for the maintenance of homeostasis. Here, we present an overview of the crosstalk between bone and other organs. Furthermore, we describe the factors mediating the crosstalk and review the mechanisms in the development of potential associated diseases. These connections shed new light on the pathogenesis of systemic diseases and provide novel potential targets for the treatment of systemic diseases.

A view on the skin–bone axis: unraveling similarities and potential of crosstalk

“…In 1972, Horton first reported the interaction between immune cells and osteocytes and discovered that immune cells stimulated by bacterial antigens produce osteoclast-activating factors ( 32 ). Immune cells play an integral role in postmenopausal osteoporosis ( 8 ). The bone and the immune system share a wide variety of molecules, including cytokines, chemokines, transcription factors, and signaling molecules ( 33 ).…”

“…In summary, both the skin and bone are closely related to the immune system ( 8 ). They share similar constituent cells (FB-OB, Langerhans cell-osteoclast) and major components (collagen), and collagen is pathologically modified by common etiologies, such as aging and drugs.…”

“…OCN is a molecule of osteoblast origin coded for by the bone γ-carboxyglutamate protein gene ( 78 ). OCN levels increase during physical activity and decrease with age ( 8 ). During progressive bone resorption, the affinity of OCN for the bone materials is reduced, and OCN is released into circulation, where it acts for other organs ( 79 ).…”

“…Thus, recently, bone has been redefined not only as a skeleton that sustains the body and protects internal organs but also as an active endocrine organ. Consequently, the bone has been demonstrated to engage in crosstalk with other organs (i.e., muscles, brain, gut, immune system, blood vessels, pancreas, kidneys, liver, and gonads) and is involved in systemic homeostasis to regulate organ activity ( 8 ). Thus, a crosstalk between the bone and many other organs has been identified; however, there are few reports evaluating the crosstalk between the bone and skin.…”

All-trans Retinoic Acid and Beta-Carotene Increase Sclerostin Production in C2C12 Myotubes

“…Skeletal muscles and bones are anatomically and biochemically linked and play critical roles in locomotion and metabolism in humans [1]. The interaction of bone and muscle has attracted increasing interest, as the two tissues are not only physically linked but can influence both muscle and bone metabolism, as well as the homeostasis of distant tissues such as the heart, liver, immune system, or adipose tissue through the release of biochemical signals [2][3][4][5][6]. These signals are called myokines if they are secreted by muscle cells or osteokines if they are produced by bone cells [7].…”