Promotion of embryonic limb cartilage differentiation in vitro by staurosporine, a protein kinase C inhibitor.
Phorbol 12-myristate 13-acetate (PMA), a protein kinase C-activating phorbol ester, is known to inhibit chondrogenic differentiation by embryonic limb mesenchyme cells in vitro. The present study demonstrates that staurosporine, a potent inhibitor of protein kinase C, conversely stimulates cartilage differentiation in cultures of limb mesenchyme cells isolated from whole wing buds of stage 23/24 chick embryos or from the distal subridge region of stage 25 wing buds. In high density micromass cultures, in which limb mesenchyme cells undergo extensive spontaneous cartilage differentiation, exposure to 5-20 nM staurosporine promotes an accelerated accumulation of type II collagen and cartilage proteoglycan mRNA transcripts and a 2- to 3-fold increase in matrix glycosaminoglycan deposition. Even in low density, monolayer cultures in which the mesenchymal cells do not normally form cartilage, treatment with 5 nM staurosporine induces extensive Alcian blue-positive matrix production, a striking 4- to 18-fold rise in sulfated glycosaminoglycan accumulation, and a dramatic elevation of cartilage-characteristic gene transcript expression. Moreover, concurrent treatment with staurosporine overcomes the inhibitory effects of PMA on in vitro limb cartilage differentiation. The results suggest the hypothesis that protein kinase C might function as a negative modulator of chondrogenic differentiation during embryonic limb development.
Kulyk
W M
WM
Department of Anatomy, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D002356:Cartilage / Q000196:embryology* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D003094:Collagen / Q000378:metabolism; D015870:Gene Expression; D006025:Glycosaminoglycans / Q000378:metabolism; D008648:Mesoderm / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014921:Wings, Animal / Q000187:drug effects / Q000196:embryology*
D000470:Alkaloids; D006025:Glycosaminoglycans; D003094:Collagen; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate