title: Osteoclast development from hematopoietic stem cells: apparent divergence of the osteoclast lineage prior to macrophage commitment.
abstract: To further clarify the progression of osteoclast development, the relationship of clonogenic osteoclast progenitors (CFU-O) to macrophage or more primitive progenitors was examined. Serum-free culture supernatant of a tumor clone (CESJ) was used as a source of an osteoclast colony stimulating factor (O-CSF). CFU-O-derived colonies were identified by their characteristic positive staining for tartrate resistant acid phosphatase (TRAPase). The effect of macrophage colony stimulating factor (M-CSF) and stem cell factor (SCF) on osteoclast progenitors was examined by pre-culturing mouse bone marrow (BM) cells in agar medium containing M-CSF or SCF and overlaying CESJ medium 0-7 days later. The number of TRAPase+ colonies decreased while TRAP- macrophage colonies increased in M-CSF pre-cultures as overlays of CESJ medium were delayed. On the other hand, TRAPase+ and mixed colonies persisted in SCF pre-cultures with CESJ medium overlays. Conversely, all colonies were TRAPase+ and no macrophage colonies developed in O-CSF pre-cultures overlaid with M-CSF. CFU-O, but not CFU-M, survived 7 days without exogenous CSFs in agar medium. In fractionated BM, the majority (> 99%) of CFU-O were in the c-kit positive population; however, a specific antibody to SCF did not affect O-CSF-induced TRAPase+ colony formation, suggesting the proliferation and differentiation of osteoclast progenitors are independent of c-kit-SCF interactions. These studies provide further experimental evidence to support the concept that O-CSF acts on progenitors in earlier stages of development, supporting their differentiation into the osteoclast lineage prior to macrophage commitment.
authors.affiliation: Department of Biological Structure, University of Washington School of Medicine, Seattle 98195, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Hayase
authors.forename: Y
authors.initials: Y
authors.lastname: Muguruma
authors.forename: M Y
authors.initials: MY
authors.lastname: Lee
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage; D002478:Cells, Cultured; D006397:Hematinics / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D008264:Macrophages / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010010:Osteoclasts / Q000166:cytology*
chemical_list: D006397:Hematinics