In vitro and in vivo suppression of osteoclast function by adenovirus vector-induced csk gene.
The proto-oncogene c-src, which encodes a non-receptor-type tyrosine kinase c-Src, has been shown to be essential for osteoclastic bone resorption by the finding that the targeted disruption of the c-src gene induced osteopetrosis in mice. The csk (C-terminal Src family kinase) gene encodes a cytoplasmic protein-tyrosine kinase that specifically phosphorylates the negative regulatory site of c-Src (Tyr-527), thereby inhibiting its kinase activity. To regulate osteoclast function by modulating the kinase activity of c-Src, we constructed an adenovirus vector that carries this gene. The recombinant adenovirus vector carrying csk cDNA induced Csk expression in mouse osteoclast-like cells formed in vitro and clearly reduced c-Src kinase activity in a dose-dependent manner. The expression of Csk caused cytoskeletal disorganization of osteoclast-like cells and strongly suppressed pit-forming activity of the cells in vitro. In addition, the viral vector carrying csk gene dramatically suppressed interleukin-1 alpha-induced bone resorption in vivo. Conversely, kinase-inactive Csk caused an increase in c-Src kinase activity and bone resorbing activity of the cells both in vitro and in vivo, acting as a dominant negative molecule against intrinsic Csk. These findings indicate that the inhibition of c-Src activity by adenovirus vector-mediated csk expression offers an efficient means for inhibiting pathological bone resorption by suppressing osteoclast function.
Miyazaki
T
T
Department of Orthopaedic Surgery, Faculty of Medicine, University of Tokyo, Japan.
Takayanagi
H
H
Isshiki
M
M
Takahashi
T
T
Okada
M
M
Fukui
Y
Y
Oda
H
H
Nakamura
K
K
Hirai
H
H
Kurokawa
T
T
Tanaka
S
S
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D001862:Bone Resorption; D000081247:CSK Tyrosine-Protein Kinase; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000648:ultrastructure; D005822:Genetic Vectors; D051379:Mice; D010010:Osteoclasts / Q000166:cytology* / Q000201:enzymology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D014443:Tyrosine; D018909:src Homology Domains; D019061:src-Family Kinases / Q000378:metabolism
D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases