Regulation of collagenolytic protease secretion through c-Src in osteoclasts.
The role of pp60c-src activity in the synthesis and secretion of the collagenolytic cysteine proteases (CCPs), cathepsin K (CAK), cathepsin L (CAL), and cathepsin B (CAB), by osteoclasts was investigated. Synthesis and secretion of CAL were up-regulated by 1alpha,25-(OH)2D3, but neither those of CAK, dominant relative to CAL, nor CAB, barely detectable, levels changed in the experiments. Though PP1, a pp60c-src inhibitor, had no effect on CCPs synthesis, suppressed the CAK and CAL secretion. Wortmannin, a phosphatidylinositol 3-kinase (PI3-kinase) inhibitor that works as a second messenger for pp60c-src, and cytochalasin B, an inhibitor of actin polymerization, suppressed the secretion of both CAK and CAL without suppressing synthesis. Hydroxyproline release, an indicator of degradation of type-I collagen, and F-actin ring formation, a structure linked to osteoclastic bone resorption, were suppressed by PP1, cytochalasin B or wortmannin. These results suggested inhibition of pp60c-src activity affected the osteoclastic cytoskeleton, which in turn reflected the suppression of bone resorption.
Furuyama
N
N
Discovery Research Laboratory, Takeda Chemical Industries, Ltd., Osaka, Japan. FURUYAMA_NAOKI@takeda.co.jp
Fujisawa
Y
Y
D000199:Actins / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D001862:Bone Resorption / Q000378:metabolism; D002117:Calcitriol / Q000494:pharmacology; D002401:Cathepsin B / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D056657:Cathepsin K; D056668:Cathepsin L; D002403:Cathepsins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D010450:Endopeptidases; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006909:Hydroxyproline / Q000378:metabolism; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000077191:Wortmannin
D000199:Actins; D000730:Androstadienes; D017931:DNA Primers; D004791:Enzyme Inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012333:RNA, Messenger; D003094:Collagen; D016392:Proto-Oncogene Proteins pp60(c-src); D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L; C534278:Ctsl protein, mouse; D056657:Cathepsin K; C534132:Ctsk protein, mouse; D002117:Calcitriol; D006909:Hydroxyproline; D000077191:Wortmannin