m6A in bone homeostasis and related diseases.

N6-methyladenosine RNA methylation (m6)A is one of the most common and widespread RNA modifications in eukaryotic cells. m6A plays a crucial role in the regulation of pathophysiological processes of eukaryotes. Three types of m6A regulators, including methyltransferases, demethylases and m6A-binding proteins, are involved in the reversible epigenetic modification of m6A. Bone is a vital organ with irreplaceable functions of movement, haematopoiesis, and protection of other organs. Its physiological homeostasis is mainly determined by the synergy of corresponding cells such as bone marrow derived stem cells, osteoblasts, and osteoclasts. Once the physiological equilibrium is broken, the bones will transform into a pathological state, resulting with diseases such as osteoporosis, osteoarthritis, rheumatoid arthritis, and osteosarcoma. Here, we review the composition of m6A and its regulation mechanism in bone physiology and pathology.