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, Volume 11, Issue 6–7, pp 556–558 | Cite as

Is platelet-activating factor (PAF-acether) synthesis by murine peritoneal cells (PC) a two-step process?

  • Jean Michel Mencia-Huerta
  • Ewa Ninio
  • Régine Roubin
  • Jacques Benveniste
Proceedings of the 3rd European Workshop on Inflammation, Paris, 2–3 March 1981 Phospholipase: Role in Cellular Activation

Abstract

PAF-acether (1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) is released from several cell sources simultaneously with an inactive non-acylated compound (1-O-alkyl-glyceryl-3-phosphorylcholine) (lyso-PAF-acether). Formation of the latter probably results from the activation of a phospholipase A2 (PLA2). Indeed, the PLA2 inhibitors, bromophenacyl bromide (BPB), mepacrine, 874CB (100 μM), and EDTA (5 mM), blocked the zymosan-induced release of PAF-acether from PC. EDTA and BPB also markedly reduced the release of lyso-PAF-acether. PAF-acether formation could involve a metabolic step linking the acetyl moiety to the 2nd carbon of lyso-PAF-acether. To verify this hypothesis, acetyl coenzyme A (acetyl-CoA) was added to stimulated PC. This enhanced the release of PAF-acether in a dose-dependent fashion from 1 μM acetyl-CoA to reach a maximal increase −200%—at 100 μM. Furthermore, using3H acetyl-CoA, incorporation of labelled acetate into PAF-acether was suggested by (1) identical chromatographic patterns of biological activity and radioactivity; (2) disappearance of these activities after treatment with PLA2, but not after exposure to lipase fromRhizopus arrhizus. PAF-acether was also obtained when both acetyl-CoA (100 μM) and synthetic lyso-PAF-acether (0.2 μM) were added to unstimulated PC previously treated with BPB (100 μM for 10 min). These results suggest that the release of PAF-acether is the consequence of at least two different steps: (1) hydrolysis of 1-O-alkyl-2-acyl-glyceryl-phosphorylcholine by PLA2; (2) enzymatic acetylation of the hydrolysis product.

Keywords

Lipase Acetyl Hydrolysis Product Cell Source Mepacrine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Birkhäuser Verlag 1981

Authors and Affiliations

  • Jean Michel Mencia-Huerta
    • 1
  • Ewa Ninio
    • 1
  • Régine Roubin
    • 1
  • Jacques Benveniste
    • 1
  1. 1.INSERM U 200ClamartFrance

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