Colony stimulating factor-1-induced osteoclast spreading depends on substrate and requires the vitronectin receptor and the c-src proto-oncogene.
The colony stimulating factor 1 (CSF-1) regulates osteoclastogenesis and bone resorption. Mutations in the CSF-1 gene cause an osteopetrosis characterized by the absence of osteoclasts. Mature osteoclasts respond to CSF-1 with inhibition of bone resorption and an increment of cell spreading. Herein we demonstrate that CSF-1-induced osteoclast spreading depends on the substrate the osteoclast interacts with and requires integrity of the vitronectin receptor and of the c-src proto-oncogene. Rabbit osteoclasts were allowed to attach to glass, serum, osteopontin, and bone substrates, and were treated with 10 ng/ml human recombinant CSF-1 for 4 h. In osteoclasts plated on glass, the cytokine induced 70% inhibition of bone resorption and 1.8-fold stimulation of cell spreading, without changes in podosome expression and microfilament array. In contrast, CSF-1 induced a 2.5-fold increase of osteoclasts showing filopodia, and a 9.5-fold increase of osteoclasts presenting lamellipodia, indicating that membrane motility was required for cell spreading. Osteoclasts plated on serum substrates showed a 50% reduction of spontaneous spreading. However, in this circumstance, CSF-1 still stimulated an increase of osteoclast area. In osteoclasts cultured on osteopontin substrate or on bone slices, an inhibition of CSF-1-induced osteoclast spreading was observed. To establish involvement of the vitronectin receptor and c-src proto-oncogene, cells were treated with the alpha vbeta3 integrin neutralizing antibody, LM609, or c-src antisense oligonucleotides, which reduced CSF-1-induced osteoclast spreading by 57% and 60%, respectively. The results demonstrate that CSF-1-induced osteoclast spreading requires both the vitronectin receptor and the c-src proto-oncogene and that this action is modulated by the adhesion substrata.
Teti
A
A
Department of Experimental Medicine, University of L'Aquila, Italy.
Taranta
A
A
Migliaccio
S
S
Degiorgi
A
A
Santandrea
E
E
Villanova
I
I
Faraggiana
T
T
Chellaiah
M
M
Hruska
K A
KA
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D016391:Genes, src / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D000090063:Proto-Oncogene Mas; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000502:physiology; D011817:Rabbits; D019030:Receptors, Vitronectin / Q000187:drug effects / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D019030:Receptors, Vitronectin; D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor; D016392:Proto-Oncogene Proteins pp60(c-src)