Bone resorption by osteoclasts.
Osteoporosis, a disease endemic in Western society, typically reflects an imbalance in skeletal turnover so that bone resorption exceeds bone formation. Bone resorption is the unique function of the osteoclast, and anti-osteoporosis therapy to date has targeted this cell. The osteoclast is a specialized macrophage polykaryon whose differentiation is principally regulated by macrophage colony-stimulating factor, RANK ligand, and osteoprotegerin. Reflecting integrin-mediated signals, the osteoclast develops a specialized cytoskeleton that permits it to establish an isolated microenvironment between itself and bone, wherein matrix degradation occurs by a process involving proton transport. Osteopetrotic mutants have provided a wealth of information about the genes that regulate the differentiation of osteoclasts and their capacity to resorb bone.
Teitelbaum
S L
SL
Department of Pathology, Washington University School of Medicine, Barnes-Jewish Hospital North, Mailstop 90-31-649, 216 South Kingshighway, St. Louis, MO 63110, USA. teitelbs@medicine wustl.edu.
D000818:Animals; D001862:Bone Resorption; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000502:physiology; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000502:physiology; D008562:Membrane Glycoproteins / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D010022:Osteopetrosis / Q000235:genetics / Q000378:metabolism; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism
D002352:Carrier Proteins; D006023:Glycoproteins; D016023:Integrins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D016173:Macrophage Colony-Stimulating Factor