Macrophage Colony Stimulating Factor Increases Bone Resorption in Dispersed Osteoclast Cultures by Increasing Osteoclast Size

Macrophage colony-stimulating factor (M-CSF) is essential for murine osteoclast formation and its role in human hematopoiesis in vitro is not fully defined. Therefore, we have investigated the effect of M-CSF on the formation of human osteoclasts in vitro. M-CSF was found to induce substantial bone resorption and osteoclast formation in a dose-responsive and time-dependent manner above that induced by 1,25 dihydroxyvitamin D3 (1,25 vitamin D3) in cultures of human bone marrow (BM) stromal cells sedimented onto devitalized bone. By day 14 there was a mean of approximately 50% of the surfaces of the bone slices resorbed compared with only 6% in cultures treated with 1,25 vitamin D3 alone. Osteoclasts were identified as 23c6+ cells (an antibody that recognizes the vitronectin receptor), 87.5% of which coexpressed the calcitonin receptor. The number of 23c6+ cells correlated strongly with bone resorption spatially, and in a dose-responsive and time-dependent manner; the correlation coefficient in cultures treated with 1,25 vitamin D3 alone was 0.856 and those treated with both M-CSF and 1,25 vitamin D3 was 0.880. Granulocyte-macrophage colony-stimulating factor, IL-1 beta, IL-3, IL-6, tumor necrosis factor-alpha, transforming growth factor-beta, leukemia inhibitory factor, and IL-11 did not increase bone resorption above that in 1,25 vitamin D3-treated cultures. We also found that 1,25 vitamin D3 increased, to a minor but significant degree, both bone resorption and the concentration of M-CSF in the culture supernatants above that in vehicle-treated cultures, indicating that M-CSF is present in our BM cultures, but that there is insufficient to induce substantial osteoclast formation. These results define a critical role for M-CSF in the formation of human osteoclasts.

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FLT3 ligand can substitute for macrophage colony-stimulating factor in support of osteoclast differentiation and function

Blood ◽

10.1182/blood.v98.9.2707 ◽

2001 ◽

Vol 98 (9) ◽

pp. 2707-2713 ◽

Cited By ~ 38

Author(s):

Jeny Maree Lean ◽

Karen Fuller ◽

Timothy John Chambers

Keyword(s):

Bone Marrow ◽

Bone Resorption ◽

Bone Marrow Cells ◽

Osteoclast Differentiation ◽

Colony Stimulating Factor ◽

Flt3 Ligand ◽

Macrophage Colony Stimulating Factor ◽

Macrophage Colony ◽

Stimulating Factor ◽

Marrow Cells

Abstract Although bone resorption and osteoclast numbers are reduced in osteopetrotic (op/op) mice, osteoclasts are nevertheless present and functional, despite the absence of macrophage colony-stimulating factor (M-CSF). This suggests that alternative factors can partly compensate for the crucial actions of M-CSF in osteoclast induction. It was found that when nonadherent bone marrow cells were incubated in RANKL with Flt3 ligand (FL) without exogenous M-CSF, tartrate-resistance acid phosphatase (TRAP)–positive cells were formed, and bone resorption occurred. Without FL, only macrophagelike TRAP-negative cells were present. Granulocyte-macrophage CSF, stem cell factor, interleukin-3, and vascular endothelial growth factor could not similarly replace the need for M-CSF. TRAP-positive cell induction in FL was not due to synergy with M-CSF produced by the bone marrow cells themselves because FL also enabled their formation from the hemopoietic cells of op/op mice, which lack any M-CSF. FL appeared to substitute for M-CSF by supporting the differentiation of adherent cells that express mRNA for RANK and responsiveness to RANKL. To determine whether FL can account for the compensation for M-CSF deficiency that occurs in vivo, FL signaling was blockaded in op/op mice by the injection of soluble recombinant Flt3. It was found that the soluble receptor induced a substantial decrease in osteoclast number, strongly suggesting that FL is responsible for the partial compensation for M-CSF deficiency that occurs in these mice.

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Vascular Endothelial Growth Factor Can Substitute for Macrophage Colony-Stimulating Factor in the Support of Osteoclastic Bone Resorption

Journal of Experimental Medicine ◽

10.1084/jem.190.2.293 ◽

1999 ◽

Vol 190 (2) ◽

pp. 293-298 ◽

Cited By ~ 303

Author(s):

Shumpei Niida ◽

Masato Kaku ◽

Hitoshi Amano ◽

Hisahiro Yoshida ◽

Hiroshi Kataoka ◽

...

Keyword(s):

Vascular Endothelial Growth Factor ◽

Growth Factor ◽

Bone Resorption ◽

Single Injection ◽

Vascular Endothelial ◽

Colony Stimulating Factor ◽

Macrophage Colony Stimulating Factor ◽

Macrophage Colony ◽

Endothelial Growth Factor ◽

Stimulating Factor

We demonstrated previously that a single injection of recombinant human macrophage colony-stimulating factor (rhM-CSF) is sufficient for osteoclast recruitment and survival in osteopetrotic (op/op) mice with a deficiency in osteoclasts resulting from a mutation in M-CSF gene. In this study, we show that a single injection of recombinant human vascular endothelial growth factor (rhVEGF) can similarly induce osteoclast recruitment in op/op mice. Osteoclasts predominantly expressed VEGF receptor 1 (VEGFR-1), and activity of recombinant human placenta growth factor 1 on osteoclast recruitment was comparable to that of rhVEGF, showing that the VEGF signal is mediated through VEGFR-1. The rhM-CSF–induced osteoclasts died after injections of VEGFR-1/Fc chimeric protein, and its effect was abrogated by concomitant injections of rhM-CSF. Osteoclasts supported by rhM-CSF or endogenous VEGF showed no significant difference in the bone-resorbing activity. op/op mice undergo an age-related resolution of osteopetrosis accompanied by an increase in osteoclast number. Most of the osteoclasts disappeared after injections of anti-VEGF antibody, demonstrating that endogenously produced VEGF is responsible for the appearance of osteoclasts in the mutant mice. In addition, rhVEGF replaced rhM-CSF in the support of in vitro osteoclast differentiation. These results demonstrate that M-CSF and VEGF have overlapping functions in the support of osteoclastic bone resorption.

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Macrophage colony-stimulating factor stimulates survival and chemotactic behavior in isolated osteoclasts.

Journal of Experimental Medicine ◽

10.1084/jem.178.5.1733 ◽

1993 ◽

Vol 178 (5) ◽

pp. 1733-1744 ◽

Cited By ~ 256

Author(s):

K Fuller ◽

J M Owens ◽

C J Jagger ◽

A Wilson ◽

R Moss ◽

...

Keyword(s):

Bone Resorption ◽

Osteoclast Formation ◽

Cell Polarization ◽

Colony Stimulating Factor ◽

Macrophage Colony Stimulating Factor ◽

Macrophage Colony ◽

And Migration ◽

Established Role ◽

Stimulating Factor

Macrophage colony-stimulating factor (M-CSF) is known to play an important role in osteoclast formation. However, its actions on mature cells have not been fully characterized. We now report that M-CSF dramatically stimulates osteoclastic motility and spreading; osteoclasts responded to a gradient of M-CSF with orientation, and random cell polarization occurred after isotropic exposure. M-CSF also supported the survival of osteoclasts by preventing apoptosis. Paradoxically, M-CSF inhibits bone resorption by isolated osteoclasts. We found that this was effected predominantly by reduction in the number of excavations. Thus, M-CSF showed a propensity to suppress resorption through a reduction in the proportion of cells that were resorbing bone. Our data suggest that apart from the established role of M-CSF in the provision of precursors for osteoclastic induction, a major role for M-CSF in bone resorption is to enhance osteoclastic survival, migration, and chemotaxis. It seems appropriate that during these processes resorptive functions should be suppressed. We suggest that M-CSF continues to modulate osteoclastic activity once osteoclasts are on resorptive sites, through regulation of the balance between resorption and migration, such that not only the quantity, but the spatial pattern of resorption can be controlled by adjacent M-CSF-secreting cells of osteoblastic lineage.

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