Abstract
Resident mouse peritoneal macrophages rapidly metabolize free arachidonic acid (20:4) in the absence of a discernible trigger. After a 20-min incubation in serumless medium, one-third of the fatty acid was found esterified in cell phospholipid and two-thirds was metabolized to oxygenated products which were recovered in the culture medium. The 20:4 oxygenated metabolites were identified by reverse-phase high performance liquid chromatography as hydroxyeicosatetraenoic acids (HETEs) and 6-keto prostaglandin F(1a) (6-ketoPGF(1a)), the stable form of prostacyclin, together with prostaglandin E(2) (PGE(2)) in proportions of 67:24:9. Inhibitor studies using indomethacin, nordihydroguaiaretic acid, and 5,8,11,14-eicosatetraenoic acid confirmed these metabolites to be lipoxygenase and cyclo-oxygenase products. The proportion of products differs considerably from those generated from phospholipid 20:4 in response to a phagocytic stimulus (HETEs:6-ketoPGF(1a):PGE(2):leukotriene C, 15:25:40: 15-20). Cornyebacterium parvum-elicited macrophages incorporated a higher percentage (70 percent) of exogenously supplied 20:4 and converted less than 20 percent of the fatty acid to oxygenated metabolites. Cyclo-oxygenase products (PGE(2), PGF(2a), TXB(2), and 6-ketoPGF(1a)) represented the major 20:4 metabolites (74 percent) synthesized by these activated macrophages. Esterification of 20:4 into cell phospholipids appeared not to be an initial obligatory step for synthesis of 20:4 oxygenated products by this route. To the contrary, incorporation of 20:4 into cell lipids and metabolism via the cyclo-oxygenase and lipoxygenase pathways represent distinct metabolic fates of exogenously supplied 20:4. These observations establish that resting macrophages contain high levels of cyclo-oxygenase and lipoxygenase activity and suggest macrophages can synthesize lipid mediators of inflammation in the absence of an inflammatory stimulus.
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- Alam I., Ohuchi K., Levine L. Determination of cyclooxygenase products and prostaglandin metabolites using high-pressure liquid chromatography and radioimmunoassay. Anal Biochem. 1979 Mar;93(2):339–345. doi: 10.1016/s0003-2697(79)80160-8. [DOI] [PubMed] [Google Scholar]
- BLIGH E. G., DYER W. J. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959 Aug;37(8):911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
- Bokoch G. M., Reed P. W. Stimulation of arachidonic acid metabolism in the polymorphonuclear leukocyte by an N-formylated peptide. Comparison with ionophore A23187. J Biol Chem. 1980 Nov 10;255(21):10223–10226. [PubMed] [Google Scholar]
- Bonney R. J., Wightman P. D., Davies P., Sadowski S. J., Kuehl F. A., Jr, Humes J. L. Regulation of prostaglandin synthesis and of the selective release of lysosomal hydrolases by mouse peritoneal macrophages. Biochem J. 1978 Nov 15;176(2):433–442. doi: 10.1042/bj1760433. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Borgeat P., Hamberg M., Samuelsson B. Transformation of arachidonic acid and homo-gamma-linolenic acid by rabbit polymorphonuclear leukocytes. Monohydroxy acids from novel lipoxygenases. J Biol Chem. 1976 Dec 25;251(24):7816–7820. [PubMed] [Google Scholar]
- Borgeat P., Samuelsson B. Arachidonic acid metabolism in polymorphonuclear leukocytes: effects of ionophore A23187. Proc Natl Acad Sci U S A. 1979 May;76(5):2148–2152. doi: 10.1073/pnas.76.5.2148. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ford-Hutchinson A. W., Bray M. A., Doig M. V., Shipley M. E., Smith M. J. Leukotriene B, a potent chemokinetic and aggregating substance released from polymorphonuclear leukocytes. Nature. 1980 Jul 17;286(5770):264–265. doi: 10.1038/286264a0. [DOI] [PubMed] [Google Scholar]
- Funk M. O., Isacc R., Porter N. A. Preparation and purification of lipid hydroperoxides from arachidonic and gamma-linolenic acids. Lipids. 1976 Feb;11(2):113–117. doi: 10.1007/BF02532660. [DOI] [PubMed] [Google Scholar]
- Goetzl E. J., Pickett W. C. Novel structural determinants of the human neutrophil chemotactic activity of leukotriene B. J Exp Med. 1981 Feb 1;153(2):482–487. doi: 10.1084/jem.153.2.482. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ingerman-Wojenski C., Silver M. J., Smith J. B., Macarak E. Bovine endothelial cells in culture produce thromboxane as well as prostacyclin. J Clin Invest. 1981 May;67(5):1292–1296. doi: 10.1172/JCI110157. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Rouzer C. A., Scott W. A., Cohn Z. A., Blackburn P., Manning J. M. Mouse peritoneal macrophages release leukotriene C in response to a phagocytic stimulus. Proc Natl Acad Sci U S A. 1980 Aug;77(8):4928–4932. doi: 10.1073/pnas.77.8.4928. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rouzer C. A., Scott W. A., Hamill A. L., Cohn Z. A. Dynamics of leukotriene C production by macrophages. J Exp Med. 1980 Nov 1;152(5):1236–1247. doi: 10.1084/jem.152.5.1236. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rouzer C. A., Scott W. A., Kempe J., Cohn Z. A. Prostaglandin synthesis by macrophages requires a specific receptor-ligand interaction. Proc Natl Acad Sci U S A. 1980 Jul;77(7):4279–4282. doi: 10.1073/pnas.77.7.4279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scott W. A., Zrike J. M., Hamill A. L., Kempe J., Cohn Z. A. Regulation of arachidonic acid metabolites in macrophages. J Exp Med. 1980 Aug 1;152(2):324–335. doi: 10.1084/jem.152.2.324. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TAPPEL A. L., LUNDBERG W. O., BOYER P. D. Effect of temperature and antioxidants upon the lipoxidase-catalyzed oxidation of sodium linoleate. Arch Biochem Biophys. 1953 Feb;42(2):293–304. doi: 10.1016/0003-9861(53)90359-2. [DOI] [PubMed] [Google Scholar]
- Unger W. G., Stamford I. F., Bennett A. Extraction of prostaglandins from human blood. Nature. 1971 Oct 1;233(5318):336–337. doi: 10.1038/233336b0. [DOI] [PubMed] [Google Scholar]
- Vane J. R. Inhibition of prostaglandin synthesis as a mechanism of action for aspirin-like drugs. Nat New Biol. 1971 Jun 23;231(25):232–235. doi: 10.1038/newbio231232a0. [DOI] [PubMed] [Google Scholar]