title: Cell line IDG-SW3 replicates osteoblast-to-late-osteocyte differentiation in vitro and accelerates bone formation in vivo.
abstract: Osteocytes are the most abundant cells in bone yet are the most challenging to study because they are embedded in a mineralized matrix. We generated a clonal cell line called IDG-SW3 (for Immortomouse/Dmp1-GFP-SW3) from long-bone chips from mice carrying a Dmp1 promoter driving GFP crossed with the Immortomouse, which expresses a thermolabile SV40 large T antigen regulated by interferon γ (IFN-γ). Cells from these mice can be expanded at 33 °C in the presence of IFN-γ and then allowed to resume their original phenotype at 37 °C in the absence of IFN-γ. IDG-SW3 cells are Dmp1-GFP(-) and T antigen(+) under immortalizing conditions but Dmp1-GFP(+) and T antigen(-) under osteogenic conditions. Like osteoblasts, they express alkaline phosphatase and produce and mineralize a type 1 collagen matrix containing calcospherulites. Like early osteocytes, they express E11/gp38, Dmp1, MEPE, and Phex. Like late osteocytes, they develop a dendritic morphology and express SOST/sclerostin and fibroblast growth factor 23 (FGF-23), regulated by parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D(3). When cultured on 3D matrices, they express Dmp1-GFP and sclerostin. When the 3D cultures are implanted in calvarial defects in vivo, they accelerate bone healing. This cell line should prove useful for studying osteoblast-to-osteocyte transition, mechanisms for biomineralization, osteocyte function, and regulation of SOST/sclerostin and FGF-23.
authors: Department of Endodontics, University of Missouri-Kansas City School of Dentistry, Kansas City, MO, USA.
authors: Stacey M
authors: SM
authors: Woo
authors: Jennifer
authors: J
authors: Rosser
authors: Vladimir
authors: V
authors: Dusevich
authors: Ivo
authors: I
authors: Kalajzic
authors: Lynda F
authors: LF
authors: Bonewald
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D002113:Calcification, Physiologic; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line / Q000166:cytology*; D002465:Cell Movement; D049109:Cell Proliferation; D005110:Extracellular Space / Q000378:metabolism; D024022:Fibrillar Collagens / Q000378:metabolism; D000089703:Fibroblast Growth Factor-23; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051379:Mice; D008863:Microspheres; D010011:Osteocytes / Q000166:cytology*; D010012:Osteogenesis; D051381:Rats; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014945:Wound Healing
chemical_list: D000952:Antigens, Polyomavirus Transforming; D015415:Biomarkers; C102116:Dmtf1 protein, mouse; C000717428:Fgf23 protein, mouse; D024022:Fibrillar Collagens; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D000089703:Fibroblast Growth Factor-23; D002118:Calcium