The Journal of Immunology, Vol 144, Issue 12 4773-4780, Copyright © 1990 by American Association of Immunologists

ARTICLES

Synthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine by an enriched preparation of the human lung mast cell

M Triggiani, WC Hubbard and FH Chilton
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224.

Our study has examined the synthesis of platelet activating factor (PAF; 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) and of structurally related molecules by an enriched preparation (greater than 70%) of the human lung mast cell (HLMC) in response to immunologic stimulation. Upon activation with anti-IgE, HLMC incorporated exogenously provided acetate into a phospholipid that migrated with authentic PAF on TLC. The formation of this product in HLMC occurred concomitantly with histamine and leukotriene C4 release. Further analysis of this phospholipid revealed that 1-acyl-2-acetyl-sn-glycero- 3-phosphocholine (GPC) and not 1-alkyl-2-acetyl-GPC was the major 1- radyl-2-acetyl-GPC subclass formed during cell activation. The presence of 1-alkyl-2-acetyl-GPC was confirmed by negative ion chemical ionization mass spectrometry. In addition to this product, anti-IgE- stimulated HLMC synthesized relatively small quantities of another 2- acetylated phospholipid migrating on TLC between phosphatidylcholine and phosphatidylinositol. The chromatographic characteristics of this product suggested that it is a subclass of 1-radyl-2-acetyl-sn-glycero- 3-phosphoethanolamine. The catabolism of both 1-acyl-2-acetyl-GPC and 1- alkyl-2-acetyl-GPC was next examined to determine if the predominant formation of 1-acyl-2-acetyl-GPC over 1-alkyl-2-acetyl-GPC were metabolized by the HLMC at similar rates. There was, however, a qualitative difference in the metabolic products derived from the two phospholipids. 1-Alkyl-2-acetyl-GPC was rapidly inactivated by removal of the acetate moiety at the sn-2 position followed by rapid reacylation with arachidonate. By contrast, 1-acyl-2-acetyl-GPC was catabolized mainly by removal of the fatty acyl moiety at the sn-1 position. These data demonstrate the natural occurrence of PAF and at least two structurally similar molecules in anti-IgE stimulated HLMC. Furthermore, an analog containing an ester linkage at the sn-1 position, 1-acyl-2-acetyl-GPC, appears to be the major acetylated product synthesized under these conditions.

This article has been cited by other articles:

				G. Montrucchio, G. Alloatti, and G. Camussi Role of Platelet-Activating Factor in Cardiovascular Pathophysiology Physiol Rev, October 1, 2000; 80(4): 1669 - 1699. [Abstract] [Full Text] [PDF]

				G. Montrucchio, E. Lupia, E. Battaglia, L. Del Sorbo, M. Boccellino, L. Biancone, G. Emanuelli, and G. Camussi Platelet-Activating Factor Enhances Vascular Endothelial Growth Factor-Induced Endothelial Cell Motility and Neoangiogenesis in a Murine Matrigel Model Arterioscler. Thromb. Vasc. Biol., January 1, 2000; 20(1): 80 - 88. [Abstract] [Full Text] [PDF]

				M. F. Brizzi, E. Battaglia, G. Montrucchio, P. Dentelli, L. Del Sorbo, G. Garbarino, L. Pegoraro, and G. Camussi Thrombopoietin Stimulates Endothelial Cell Motility and Neoangiogenesis by a Platelet-Activating Factor–Dependent Mechanism Circ. Res., April 16, 1999; 84(7): 785 - 796. [Abstract] [Full Text] [PDF]

				G. Montrucchio, A. Sapino, B. Bussolati, G. Ghisolfi, S. Rizea-Savu, L. Silvestro, E. Lupia, and G. Camussi Potential Angiogenic Role of Platelet-Activating Factor in Human Breast Cancer Am. J. Pathol., November 1, 1998; 153(5): 1589 - 1596. [Abstract] [Full Text] [PDF]

				M. Triggiani, V. De Marino, M. Sofia, S. Faraone, G. Ambrosio, L. Carrat, and G. Marone Characterization of Platelet-activating Factor Acetylhydrolase in Human Bronchoalveolar Lavage Am. J. Respir. Crit. Care Med., July 1, 1997; 156(1): 94 - 100. [Abstract] [Full Text]

				G. Montrucchio, E. Lupia, A. De Martino, L. Silvestro, S. R. Savu, G. Cacace, P.G. De Filippi, G. Emanuelli, and G. Camussi Plasmin Promotes an Endothelium-Dependent Adhesion of Neutrophils : Involvement of Platelet Activating Factor and P-Selectin Circulation, June 15, 1996; 93(12): 2152 - 2160. [Abstract] [Full Text]

				H. W. Mueller, C. A. Haught, J. M. McNatt, K. Cui, S. J. Gaskell, D. A. Johnston, and J. T. Willerson Measurement of Platelet-Activating Factor in a Canine Model of Coronary Thrombosis and in Endarterectomy Samples From Patients With Advanced Coronary Artery Disease Circ. Res., July 1, 1995; 77(1): 54 - 63. [Abstract] [Full Text]