HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pérez, R. Articles by Balsinde, J. Search for Related Content PubMed PubMed Citation Articles by Pérez, R. Articles by Balsinde, J.

Involvement of Group VIA Calcium-Independent Phospholipase A₂ in Macrophage Engulfment of Hydrogen Peroxide-Treated U937 Cells¹

Institute of Molecular Biology and Genetics, Spanish Research Council and University of Valladolid School of Medicine, Valladolid, Spain

Hydrogen peroxide-induced apoptosis of U937 cells results in substantial hydrolysis of membrane phospholipids by calcium-independent group VIA phospholipase A₂ (iPLA₂-VIA). However, abrogation of cellular iPLA₂-VIA neither delays nor decreases apoptosis, suggesting that, beyond a mere destructive role, iPLA₂-VIA may serve other specific roles. In this study, we report that phagocytosis of apoptosing U937 cells by macrophages is blunted if the cells are depleted of iPLA₂-VIA by treatment with an inhibitor or an antisense oligonucleotide, and it is augmented by overexpression of iPLA₂-VIA in the dying cells. Thus, the magnitude of macrophage phagocytosis correlates with the level of iPLA₂-VIA activity of the dying cells. Eliminating by antisense oligonucleotide technology of cytosolic group IVA phospholipase A₂ does not attenuate phagocytosis of U937 dying cells by macrophages. Incubation of U937 cells with different fatty acids has no effect on either the extent of hydrogen peroxide-induced apoptosis or the degree of phagocytosis of the dying cells by macrophages. However, preincubation of the macrophages with lysophosphatidylcholine before exposing them to the dying cells blocks phagocytosis of the latter. These results indicate that formation of lysophosphatidylcholine by iPLA₂-VIA in hydrogen peroxide-treated U937 cells to induce apoptosis directly contributes to their efficient clearance by macrophages.

This article has been cited by other articles:

				A. Gubern, M. Barcelo-Torns, J. Casas, D. Barneda, R. Masgrau, F. Picatoste, J. Balsinde, M. A. Balboa, and E. Claro Lipid Droplet Biogenesis Induced by Stress Involves Triacylglycerol Synthesis That Depends on Group VIA Phospholipase A2 J. Biol. Chem., February 27, 2009; 284(9): 5697 - 5708. [Abstract] [Full Text] [PDF]

				S. Y. Kim, H.-Y. Jo, M. H. Kim, Y.-y. Cha, S. W. Choi, J.-H. Shim, T. J. Kim, and K.-Y. Lee H2O2-dependent Hyperoxidation of Peroxiredoxin 6 (Prdx6) Plays a Role in Cellular Toxicity via Up-regulation of iPLA2 Activity J. Biol. Chem., November 28, 2008; 283(48): 33563 - 33568. [Abstract] [Full Text] [PDF]

				J. Pindado, J. Balsinde, and M. A. Balboa TLR3-Dependent Induction of Nitric Oxide Synthase in RAW 264.7 Macrophage-Like Cells via a Cytosolic Phospholipase A2/Cyclooxygenase-2 Pathway J. Immunol., October 1, 2007; 179(7): 4821 - 4828. [Abstract] [Full Text] [PDF]

				V. Ruiperez, J. Casas, M. A. Balboa, and J. Balsinde Group V Phospholipase A2-Derived Lysophosphatidylcholine Mediates Cyclooxygenase-2 Induction in Lipopolysaccharide-Stimulated Macrophages J. Immunol., July 1, 2007; 179(1): 631 - 638. [Abstract] [Full Text] [PDF]

				M. Kolko, J. Wang, C. Zhan, K. A. Poulsen, J. U. Prause, M. H. Nissen, S. Heegaard, and N. G. Bazan Identification of Intracellular Phospholipases A2 in the Human Eye: Involvement in Phagocytosis of Photoreceptor Outer Segments Invest. Ophthalmol. Vis. Sci., March 1, 2007; 48(3): 1401 - 1409. [Abstract] [Full Text] [PDF]