title: Osteoblasts of calvaria induce higher numbers of osteoclasts than osteoblasts from long bone.
abstract: Several studies have demonstrated the existence of functional differences between osteoclasts harbored in different bones. The mechanisms involved in the occurrence of such a heterogeneity are not yet understood. Since cells of the osteoblast lineage play a critical role in osteoclastogenesis, osteoclast heterogeneity may be due to osteoblasts that differ at the different bone sites. In the present study we evaluated possible differences in the capacity of calvaria and long bone osteoblasts to induce osteoclastogenesis. Osteoblasts were isolated from calvaria and long bone of mice and co-cultured with osteoclast precursors obtained from bone marrow of both types of bone, spleen and peripheral blood. Irrespective of the source of the precursors, a significantly higher number of TRACP-positive multinucleated cells were formed with calvaria osteoblasts. The expression of osteoclastogenesis related genes was analyzed by qPCR. OPG was significantly higher expressed by long bone osteoblasts. The RANKL/OPG ratio and TNF-α gene expression were significantly higher in calvaria osteoblast cultures. OPG added to the culture system inhibited osteoclastogenesis in both groups. Blocking TNF-α had no effect on osteoclastogenesis. Calvaria and long bone osteoblasts were pre-stimulated with VitD3 for 5days. Subsequently, osteoclast precursors were added to these cultures. After a co-culture of 6days, it was shown that VitD3 pre-stimulation of long bone osteoblasts strongly improved their capacity to induce osteoclast formation. This coincided with an increased ratio of RANKL/OPG. Taken together, the data demonstrated differences in the capacity of calvaria and long bone osteoblasts to induce osteoclastogenesis. This appeared to be due to differences in the expression of RANKL and OPG. VitD3 pre-stimulation improved the ability of long bone osteoblasts to induce osteoclast formation. Our findings demonstrate bone-site specific differences in osteoblast-mediated formation of osteoclasts. The data may suggest that the heterogeneity of osteoclasts is partially due to the way the osteoblasts induce their formation.
authors.affiliation: Department of Oral Cell Biology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: Qilong
authors.initials: Q
authors.lastname: Wan
authors.affiliation: Periodontology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands.
authors.forename: Ton
authors.initials: T
authors.lastname: Schoenmaker
authors.affiliation: Periodontology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands.
authors.forename: Ineke D C
authors.initials: ID
authors.lastname: Jansen
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: Zhuan
authors.initials: Z
authors.lastname: Bian
authors.affiliation: Periodontology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands.
authors.forename: Teun J
authors.initials: TJ
authors.lastname: de Vries
authors.affiliation: Department of Oral Cell Biology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands. Electronic address: v.everts@acta.nl.
authors.forename: Vincent
authors.initials: V
authors.lastname: Everts
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000166:cytology*; D002452:Cell Count; D002469:Cell Separation; D002762:Cholecalciferol / Q000494:pharmacology; D018920:Coculture Techniques; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics; D010641:Phenotype; D053245:RANK Ligand / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012886:Skull / Q000166:cytology*; D000071681:Tartrate-Resistant Acid Phosphatase / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D053245:RANK Ligand; D014409:Tumor Necrosis Factor-alpha; D002762:Cholecalciferol; D000071681:Tartrate-Resistant Acid Phosphatase
keywords: Calvaria; Co-culture; Long bone; Osteoblast; Osteoclast heterogeneity