Macrophage colony-stimulating factor is indispensable for both proliferation and differentiation of osteoclast progenitors.
The mechanism of action of macrophage colony-stimulating factor (M-CSF) in osteoclast development was examined in a co-culture system of mouse osteoblastic cells and spleen cells. In this co-culture, osteoclast-like multinucleated cells (MNCs) were formed within 6 d in response to 10 nM 1 alpha,25(OH)2D3 added only for the final 2 d of culture. Simultaneously adding hydroxyurea for the final 2 d completely inhibited proliferation of cultured cells without affecting 1 alpha,25(OH)2D3-stimulated MNC formation. Autoradiographic examination using [3H]-thymidine revealed that osteoclast progenitors primarily proliferated during the first 4 d, whereas their differentiation into MNCs occurred predominantly during the final 2 d of culture in response to 1 alpha,25(OH)2D3. When anti-M-CSF antibody or anti-M-CSF receptor antibody was added either for the first 4 d or for the final 2 d, the MNC formation was similarly inhibited. In co-cultures of normal spleen cells and osteoblastic cells obtained from op/op mice, which cannot produce functionally active M-CSF, the lack of M-CSF either for the first 4 d or for the final 2 d failed to form MNCs in response to 1 alpha,25(OH)2D3 added for the last 2 d. These results clearly indicate that M-CSF is indispensable for both proliferation of osteoclast progenitors and their differentiation into mature osteoclasts.
Tanaka
S
S
Department of Biochemistry, Showa University, School of Dentistry, Tokyo, Japan.
Takahashi
N
N
Udagawa
N
N
Tamura
T
T
Akatsu
T
T
Stanley
E R
ER
Kurokawa
T
T
Suda
T
T
D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005260:Female; D016236:Genes, fms; D006918:Hydroxyurea / Q000494:pharmacology; D007700:Kinetics; D016173:Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000502:physiology; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors
D000906:Antibodies; D016173:Macrophage Colony-Stimulating Factor; D004247:DNA; D016186:Receptor, Macrophage Colony-Stimulating Factor; D002117:Calcitriol; D013936:Thymidine; D006918:Hydroxyurea