Antisense inhibition of group VI Ca2+-independent phospholipase A2 blocks phospholipid fatty acid remodeling in murine P388D1 macrophages.
A major issue in lipid signaling relates to the role of particular phospholipase A2 isoforms in mediating receptor-triggered responses. This has been difficult to study because of the lack of isoform-specific inhibitors. Based on the use of the Group VI Ca2+-independent phospholipase A2 (iPLA2) inhibitor bromoenol lactone (BEL), we previously suggested a role for the iPLA2 in mediating phospholipid fatty acid turnover (Balsinde, J., Bianco, I. D., Ackermann, E. J., Conde-Frieboes, K., and Dennis, E. A. (1995) Proc. Natl. Acad. Sci. U. S. A. 92: 8527-8531). We have now further evaluated the role of the iPLA2 in phospholipid remodeling by using antisense RNA technology. We show herein that inhibition of iPLA2 expression by a specific antisense oligonucleotide decreases both the steady-state levels of lysophosphatidylcholine and the capacity of the cell to incorporate arachidonic acid into membrane phospholipids. These effects correlate with a decrease in both iPLA2 activity and protein in the antisense-treated cells. Collectively these data provide further evidence that the iPLA2 plays a major role in regulating phospholipid fatty acyl turnover in P388D1 macrophages. In stark contrast, experiments with activated cells confirmed that the iPLA2 does not play a significant role in receptor-coupled arachidonate mobilization in these cells, as manifested by the lack of an effect of the iPLA2 antisense oligonucleotide on PAF-stimulated arachidonate release.
Balsinde
J
J
Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093-0601, USA.
Balboa
M A
MA
Dennis
E A
EA
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D007941:Leukemia P388 / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D010741:Phospholipases A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism*; D011753:Pyrones / Q000494:pharmacology
D008563:Membrane Lipids; D009281:Naphthalenes; D016376:Oligonucleotides, Antisense; D010743:Phospholipids; D011753:Pyrones; D016718:Arachidonic Acid; C068314:6-(bromomethylene)tetrahydro-3-(1-naphthaleneyl)-2H-pyran-2-one; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium