Osteoclast differentiation and bone resorption pathways

The osteoclast differentiation and bone resorption pathways encompass the complex signaling and cellular processes required for the formation and activation of bone-resorbing cells (KEGG: map04380). Central to these pathways is the RANK/RANKL/OPG axis, where the binding of Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL) to its receptor RANK on osteoclast precursors drives their maturation into functional, multinucleated osteoclasts (Boyce & Xing, 2008; PubMed: 18292213). Mature osteoclasts then execute bone resorption by creating an acidic microenvironment and secreting proteolytic enzymes, such as Cathepsin K, to dissolve the mineral and organic components of the bone matrix (StatPearls: Osteoclast). Dysregulation of these pathways is a hallmark of metabolic bone diseases such as osteoporosis, as well as inflammatory conditions like rheumatoid arthritis and skeletal complications of cancer (NIH: Osteoporosis). Therapeutic strategies often focus on inhibiting these pathways to preserve bone density, with drugs like denosumab targeting RANKL and bisphosphonates inducing osteoclast apoptosis (FDA: Prolia; PubMed: 21170531). Emerging therapies also target regulatory proteins like sclerostin to indirectly modulate these resorption pathways and favor bone formation (Amgen: Evenity).

Other names

Osteoclastogenesis pathwayRANK/RANKL/OPG signaling pathwayBone remodeling processKEGG: map04380

Inhibition of RANKL-RANK interaction, induction of osteoclast apoptosis, and inhibition of bone-degrading enzymes such as Cathepsin K.