Osteoclasts are multinucleated cells with the specialized function of resorbing calcified tissues. These cells develop from hemopoietic cells of the monocyte-macrophage lineage with the support of osteoblasts/stromal cells. Tooth eruption is a vertical movement of teeth via creation of an eruption pathway in and through the alveolar bone. The precise cellular and molecular determinants of tooth eruption are not yet clear, and a cell culture system that can reproduce the activity of osteoclast formation during tooth eruption is expected to be a useful tool to clarify the mechanism of eruption pathway formation. To this end, mandibular bodies, including incisors and molars, were isolated from 9- to 11-day-old @entity19 undergoing active tooth eruption. Primary cells were obtained from mandibular bodies by enzymatic digestion and cultured in alphaMEM containing 15% FBS without any cytokine or growth factor or hormone in the culture (AFT culture, for alveolar bone, dental follicle, and tooth). A progressive increase in the number of @entity5272 -resistant acid phosphatase-positive multinucleated osteoclastic cells was observed in AFT culture. The osteoclastic cells generated were immunopositive for cathepsin K and @entity175 receptor, and formed resorption pits when cultured on dentine slices. @entity25737 ( @entity25737 ), expressed by the enamel organ of tooth, is reported to be an essential factor in creation of the eruption pathway. To verify this point, cells were isolated from mandibular bodies from which all teeth and dental follicles had been removed and cultured similarly (A culture, for alveolar bone). Osteoclastic cells were not formed and @entity25737 production was hardly detected in the medium of A culture, in contrast to the high level of @entity25737 in AFT culture. Since our previous study demonstrated that neonatal homozygous @entity25737 -knockout @entity19 show @entity73 around tooth germs, AFT culture was performed by using this sample to examine whether this culture system can reproduce the status of osteoclastogenesis observed in vivo. The result showed that none of the osteoclastic cells were generated from cells of homozygous @entity19 . We here report a novel @entity19 osteoclast culture system that reproduces the activity of osteoclast formation around erupting teeth without addition of any cytokine or growth factor or hormone to the medium. Histological examination of various transgenic and mutant @entity19 now offers valuable findings on studies of tooth eruption and the present culture system using these animals would be a powerful tool in clarifying the cellular and molecular mechanisms of eruption pathway formation.

Development of a novel XXXX osteoclast culture system including cells of mandibular body and erupting teeth.

@entity5272 :: ('MESH:C029768', 'Chemical') :: ['tartrate'] @entity175 :: ('MESH:D002116', 'Chemical') :: ['calcitonin'] @entity25737 :: ('19227(Tax:10090)', 'Gene') :: ['PTHrP', 'Parathyroid hormone-related protein'] @entity19 :: ('10090', 'Species') :: ['mice', 'mouse'] @entity73 :: ('MESH:D003072', 'Disease') :: ['impaired osteoclastogenesis']
@entity19 :: (10090,Species) :: ['mouse']
