Inhibitory effects of phospholipase D on chondrogenesis in vitro

Mesenchymal cells from the wing buds of stage 24 chick embryos undergo differentiation to cartilage when plated at high density. Treatment of these cultures with phospholipase D resulted in inhibition of chondrogenesis. Phospholipase D treatment (which produces phosphatidic acid from membrane phospholipids) was found to affect cell proliferation and to dramatically increase intracellular free calcium levels and inositol phosphate production. Intracellular free Ca2+, mobilized as a result of phosphatidylinositol phosphate hydrolysis, may therefore inhibit chondrogenesis in embryonic mesenchymal cells.