Bone metabolism pathway

The bone metabolism pathway encompasses the network of cellular and molecular mechanisms that regulate bone remodeling, including bone formation by osteoblasts, bone resorption by osteoclasts, and regulatory actions of osteocytes. This involves hormone signaling (e.g., parathyroid hormone, estrogen), cytokines (e.g., RANKL, OPG), metabolic intermediates (e.g., citrate), and multiple intracellular signaling routes such as Wnt, BMP, PTH1R, and others. Pathway dysregulation underlies metabolic bone diseases such as osteoporosis, bone fractures, and abnormal bone growth disorders. Individual nodes within this pathway—like RANKL, sclerostin, and PTH1R—serve as drug targets, but the "bone metabolism pathway" itself is too broad and non-specific to be defined as a single molecular target for therapeutic intervention.