1,25(OH)2D3 Regulates Protein Kinase C Activity Through Two Phospholipid-Dependent Pathways Involving Phospholipase A2 and Phospholipase C in Growth Zone Chondrocytes

• DOI: 10.1359/jbmr.1998.13.4.559
• Publication Date: 2006-04-27T00:31:28Z
• Authors: V. L. Sylvia; Z. Schwartz; D. B. Curry; Z. Chang; D. D. Dean; B. D. Boyan
• Keywords: Phospholipase D

Abstract We have previously shown that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plays a major role in growth zone chondrocyte (GC) differentiation and this effect is mediated by protein kinase C (PKC). The aim of the present study was to identify signal transduction pathway used 1,25(OH)2D3 stimulate PKC activation. Confluent, fourth passage GC cells from costochondral cartilage were evaluate mechanism Treatment cultures with elicited dose-dependent increase both inositol-1,4,5-trisphosphate diacylglycerol (DAG) production, suggesting for phospholipase potentially D. Addition dioctanoylglycerol plasma membranes isolated GCs increased activity. Neither pertussis toxin nor choleratoxin had an inhibitory on activity control or 1,25(OH)2D3-treated GCs, indicating neither Gi Gs proteins involved. Phospholipase A2 inhibitors, quinacrine, OEPC (selective secretory A2), AACOCF3 cytosolic cyclooxygenase inhibitor indomethacin decreased activity, while activators melittin mastoparan cultures. Arachidonic acid prostaglandin E2, two downstream products action, also These results indicate 1,25(OH)2D3-dependent stimulation regulated distinct phospholipase-dependent mechanisms: production DAG, primarily via arachidonic A2.