The broad objective of this proposal is to evaluate the role of lipoxygenase-derived (LO) products in the pathophysiology of human disease. Since oxygenation products of arachidonic (e.g leukotrienes (LT)) are held to play important roles in inflammation, complete knowledge of their 1) sites of generation and degradation (in vivo), 2) biosynthesis, and 3) actions is essential. Because evidence is lacking, in many cases, for documentation of LO products (leukotrienes, lipoxins (LX)) and their metabolites at sites of inflammation, a method was developed employing gradient-HPLC with a photodiode array and gas chromatography-mass spectroscopy for their identification in human exudates.
The aims of this proposal include: 1) Profiling LO products (LT, LX, w-products) in pleural (malignancy vs. pleuritis), synovial (septic vs. osteo-and rheumatoid arthritis) exudates and bronchoalveolar lavages from patients with sarcoidosis. Here comparisons will be made between profiles n exudates and establish the balance between 5-, 12-, 15-LO pathway-derived products. 2) Extracellular phospholipase A2 (PLA2) activity will be determined n and isolated from pleural and synovial fluids. Here, utilizing human neutrophils (PMN), the hypothesis will be tested that extracellular PLA2 may serve as a trigger for LO product formation. Stimuli that provoke the release of PMN granule- associated PLA2 will be identified and the temporal relationship between PLA2 releae and LO product formation established. The presence and properties of PLA2 isoenzymes will be determined in both exudates and PMN. 3) Isolation of the epoxide hydrolase (s) from PMN involved in the biosynthesis of lipoxins. 4) Examining the actions of LO products, including eicosanoid epoxides, on PMN responses. Here Ca2+ mobilization, lysosomal enzyme release, and the generation of reactive oxygen will be studied. Throughout, focus will be on identification of novel or """"""""degradation"""""""" products from human fluids and PMN that may regulate PMN responses. Results from these studies will provide a framework for understanding the role and sites of formation of LO products in the pathophysiology of inflammation. In addition, they will provide a basis for both the design and evaluation of pharmacologic interventions in specific disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI026714-01
Application #
3140594
Study Section
(SRC)
Project Start
1988-07-01
Project End
1991-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
1
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
071723621
City
Boston
State
MA
Country
United States
Zip Code
02115
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Brezinski, D A; Serhan, C N (1991) Characterization of lipoxins by combined gas chromatography and electron-capture negative ion chemical ionization mass spectrometry: formation of lipoxin A4 by stimulated human whole blood. Biol Mass Spectrom 20:45-52
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Serhan, C N; Brezinski, M E (1991) Selective incorporation of 15-HETE in phosphatidylinositol: agonist-induced deacylation and transformation of stored HETEs by human neutrophils. Adv Prostaglandin Thromboxane Leukot Res 21A:105-8
Fiore, S; Brezinski, M E; Sheppard, K A et al. (1991) The lipoxin biosynthetic circuit and their actions with human neutrophils. Adv Exp Med Biol 314:109-32
Fiore, S; Nigam, S; Serhan, C N (1991) Lipoxins trigger the release but not the oxygenation of arachidonic acid in human neutrophils: dissociation between lipid remodeling and adhesion. Adv Prostaglandin Thromboxane Leukot Res 21B:553-6
Brezinski, M E; Serhan, C N (1990) Selective incorporation of (15S)-hydroxyeicosatetraenoic acid in phosphatidylinositol of human neutrophils: agonist-induced deacylation and transformation of stored hydroxyeicosanoids. Proc Natl Acad Sci U S A 87:6248-52

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