Adenine nucleotides modulate phosphatidylcholine metabolism in aortic endothelial cells.
ATP and ADP, in concentrations ranging from 1-100 microM, increased the release of [3H]choline and [3H]phosphorylcholine (P-choline) from bovine aortic endothelial cells (BAEC) prelabelled with [3H]choline. This action was detectable within 5 minutes and was maintained for at least 40 minutes. ATP and ADP were equiactive, and their action was mimicked by their phosphorothioate analogs (ATP gamma S and ADP beta S) and adenosine 5'-(beta, gamma imido) triphosphate (APPNP), but not by AMP, adenosine, and adenosine 5'-(alpha, beta methylene)triphosphate (APCPP): these results are consistent with the involvement of P2Y receptors. ATP also induced an intracellular accumulation of [3H]choline: the intracellular level of [3H]choline was increased 30 seconds after ATP addition and remained elevated for a least 20 minutes. The action of ATP on the release of choline metabolites was reproduced by bradykinin (1 microM), the tumor promoter phorbol 12-myristate 13-acetate (PMA, 50 nM), and the calcium ionophore A23187 (0.5 microM). Down-regulation of protein kinase C, following a 24-hour exposure of endothelial cells to PMA, abolished the effects of PMA and ATP on the release of choline and P-choline, whereas the response to A23187 was maintained. These results suggest that in aortic endothelial cells, ATP produces a sustained activation of a phospholipase D hydrolyzing phosphatidylcholine. The resulting accumulation of phosphatidic acid might have an important role in the modulation of endothelial cell function by adenine nucleotides. Stimulation of phospholipase D appears to involve protein kinase C, activated following the release of diacylglycerol from phosphatidylinositol bisphosphate by a phospholipase C coupled to the P2Y receptors (Pirotton et al., 1987a).
Pirotton
S
S
Institute of Interdisciplinary Research, School of Medicine, Free University of Brussels, Belgium.
Robaye
B
B
Lagneau
C
C
Boeynaems
J M
JM
D000227:Adenine Nucleotides / Q000502:physiology*; D000818:Animals; D001011:Aorta; D001920:Bradykinin / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002417:Cattle; D002772:Cholera Toxin / Q000494:pharmacology; D002794:Choline / Q000378:metabolism; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology; D066298:In Vitro Techniques; D037342:Pertussis Toxin; D010713:Phosphatidylcholines / Q000378:metabolism*; D011493:Protein Kinase C / Q000502:physiology; D011983:Receptors, Purinergic / Q000502:physiology; D013329:Structure-Activity Relationship; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000227:Adenine Nucleotides; D010713:Phosphatidylcholines; D011983:Receptors, Purinergic; D010566:Virulence Factors, Bordetella; D000001:Calcimycin; D002772:Cholera Toxin; D037342:Pertussis Toxin; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D002794:Choline; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin; D002118:Calcium