Group V phospholipase A2-mediated oleic acid mobilization in lipopolysaccharide-stimulated P388D1 macrophages

Jesús Balsinde, María A. Balboa, Saul Yedgar, Edward A. Dennis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

P338D1 macrophages prelabeled with [3H]arachidonic acid (AA) respond to bacterial lipopolysaccharide (LPS) by mobilizing AA in a process that takes several hours and is mediated by the concerted actions of the group IV cytosolic phospholipase A2 and the group V secretory phospholipase A2 (sPLA2). Here we show that when the LPS-activated cells are prelabeled with [3H]oleic acid (OA), they also mobilize and release OA to the extracellular medium. The time and concentration dependence of the LPS effect on OA release fully resemble those of the AA release. Experiments in which both AA and OA release are measured simultaneously indicate that AA is released 3 times more efficiently than OA. Importantly, LPS-stimulated OA release is strongly inhibited by the selective sPLA2 inhibitors 3-(3-acetamide-1-benzyl-2- ethylindolyl-5-oxy)propane sulfonic acid and carboxymethylcellulose-linked phosphatidylethanolamine. The addition of exogenous recombinant sPLA2 to the cells also triggers OA release. These data implicate a functionally active sPLA2 as being essential for the cells to release OA upon stimulation with LPS. OA release is also inhibited by methyl arachidonyl fluorophosphonate but not by bromoenol lactone, indicating that the group IV cytosolic phospholipase A2 is also involved in the process. Together, these data reveal that OA release occurs during stimulation of the P388D1 macrophages by LPS and that the regulatory features of the OA release are strikingly similar to those previously found for the AA release.

Original languageEnglish
Pages (from-to)4783-4786
Number of pages4
JournalJournal of Biological Chemistry
Volume275
Issue number7
DOIs
StatePublished - 18 Feb 2000

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