Crosstalk between Bone and Muscles during Physical Activity

Abstract

Bone–muscle crosstalk is enabled thanks to the integration of different molecular signals, and it is essential for maintaining the homeostasis of skeletal and muscle tissue. Both the skeletal system and the muscular system perform endocrine activity by producing osteokines and myokines, respectively. These cytokines play a pivotal role in facilitating bone–muscle crosstalk. Moreover, recent studies have highlighted the role of non-coding RNAs in promoting crosstalk between bone and muscle in physiological or pathological conditions. Therefore, positive stimuli or pathologies that target one of the two systems can affect the other system as well, emphasizing the reciprocal influence of bone and muscle. Lifestyle and in particular physical activity influence both the bone and the muscular apparatus by acting on the single system but also by enhancing its crosstalk. Several studies have in fact demonstrated the modulation of circulating molecular factors during physical activity. These molecules are often produced by bone or muscle and are capable of activating signaling pathways involved in bone–muscle crosstalk but also of modulating the response of other cell types. Therefore, in this review we will discuss the effects of physical activity on bone and muscle cells, with particular reference to the biomolecular mechanisms that regulate their cellular interactions.

Mechanism and physical activities in bone-skeletal muscle crosstalk

“…Irisin secreted by skeletal muscle during exercise can increase the differentiation of osteoblasts in vivo . Exercise promotes the release of irisin, enhances the expression of RUNX2, stimulates the differentiation of osteoblasts, and inhibits transforming growth factor-β (TGF-β) signal transduction and SOST gene, thus promoting bone formation and improving bone density ( 76 ). After resistance exercise, the serum IGF-1 protein level increased ( 77 ).…”

“…PGC-1α4 can combine resistance training with a gene program of muscle hypertrophy, increase muscle mass and strength, and have a significant effect on resisting muscle atrophy. Furthermore, PGC-1α can play a positive role in maintaining bone growth and osteogenic differentiation ( 76 , 82 ). Therefore, exercise can be used as a reasonable non-drug treatment for patients with sarcopenia and osteoporosis.…”