title: [Mechanism of bone mass regulation by mechanical stress].
abstract: Osteocytes establish an extensive intercellular and extracellular communication system via gap junction-coupled cell processes and canaliculi, through which cell processes pass throughout bone, and the communication system is extended to osteoblasts on the bone surface. The lacunocanalicular network formed by osteocytes is thought to be an ideal mechanosensory system and suitable for mechanotransduction, by which mechanical energy is converted into electrical and/or biochemical signals. The function of osteocytes cannot be estimated based on the events caused by osteocyte death, because apoptotic osteocytes are not phagocytosed, undergo secondary necrosis, and trigger a process of repair to replace the damaged bone. The analysis of the mice, in which both intercellular and extracellular communication systems are disturbed, shows that the osteocyte network mildly inhibits bone formation and mildly stimulates bone resorption in physiological condition. In unloaded condition, the functions of the osteocyte network are augmented, and it strongly inhibits bone formation and strongly stimulates bone resorption, at least in part, through the induction of Sost in osteocytes and Rankl in osteoblasts.
authors.affiliation: Nagasaki University Graduate School of Biomedical Sciences, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Komori
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis; D015519:Bone Density / Q000502:physiology*; D019485:Bone Morphogenetic Proteins; D001862:Bone Resorption / Q000235:genetics; D002450:Cell Communication; D017629:Gap Junctions / Q000502:physiology; D005819:Genetic Markers; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology; D051379:Mice; D009336:Necrosis; D010006:Osteoblasts / Q000502:physiology; D010011:Osteocytes / Q000502:physiology*; D010012:Osteogenesis / Q000235:genetics; D053245:RANK Ligand; D013314:Stress, Mechanical; D060449:Wnt Signaling Pathway / Q000235:genetics / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; D053245:RANK Ligand; C422903:SOST protein, human