Lipoxygenases metabolize arachidonic acid to an array of oxygenated products including leukotrienes, monohydroxyeicosatetraenoic acids (HETE), and lipoxins with broad spectrums of biological activities. Two 12- lipoxygenase isozymes categorized as """"""""platelet-type"""""""" (P-12LO) and """"""""leukocyte-type"""""""" (L-12LO) have been isolated and characterized. P-12LO is found in platelets and skin. L-12LO exhibits a widespread distribution. We propose that the two 12LO isozymes possess distinct biological functions based on their different biochemical properties and localization. Absence of good, specific 12LO inhibitors has prevented definitive studies regarding 12LO function, so far. Therefore, a targeted gene disruption strategy will be invoked to generate P-12LO and L-12LO deficient mice. Initial studies, however, will focus on refining in detail the cell specific sites of 12LO expression in normal mice, in particular, looking at P-12LO expression in skin and L-12LO expression in blood cells, epithelial cells lining the airways, and organs like pancreas and adrenal gland. 12(S)-HETE can evoke endothelial cell retraction, surface integrin expression on endothelial cells and tumor cells, and keratinocyte chemotaxis at nanomolar concentrations. P-12LO deficient mice will be tested for various platelet function parameters ex vivo and hemostatic competence in vivo. Skin function in relation to wound healing, maintenance of the permeability barrier and psoriasis will be examined. In L-12LO deficient mice, on the other hand, blood cells will be tested for chemotaxis, phagocytosis and alterations in membrane properties in response to cellular activation. Mouse models of inflammation will be induced to examine the importance of L-12LO in the inflammatory response. 12(S)-HETE has been proposed to modulate glucose-induced insulin secretion and angiotensin II-induced aldosterone synthesis. The absence of this lipoxygenase product in L-12LO-deficient mice will permit testing the importance of this pathway in these key pancreatic and adrenal functions. Experiments to delineate the relationship of the highly related L-12LO and 15-lipoxygenase (15LO) enzymes will be performed. Finally, the murine P- 12LO and L-12LO enzymes, which share 58 % sequence identity, will be studied by in vitro mutagenesis experiments to elucidate some of the molecular properties responsible for governing the specificity differences of the two 12LO isozymes. The proposed studies here should contribute significantly to our understanding of the biological importance of 12LO products.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL053558-06
Application #
2839011
Study Section
Medical Biochemistry Study Section (MEDB)
Project Start
1994-12-01
Project End
1999-11-30
Budget Start
1998-12-01
Budget End
1999-11-30
Support Year
6
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Pharmacology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
FitzGerald, Garret A (2008) Translational therapeutics at the platelet vascular interface. Introduction. Arterioscler Thromb Vasc Biol 28:s3-4
FitzGerald, Garret A (2008) Translational therapeutics at the platelet vascular interface. Summary. Arterioscler Thromb Vasc Biol 28:s51-2
Cao, Richard Yang; Adams, Michael A; Habenicht, Andreas J et al. (2007) Angiotensin II-induced abdominal aortic aneurysm occurs independently of the 5-lipoxygenase pathway in apolipoprotein E-deficient mice. Prostaglandins Other Lipid Mediat 84:34-42
Funk, Colin D; Cao, Richard Yang; Zhao, Lei et al. (2006) Is there a role for the macrophage 5-lipoxygenase pathway in aortic aneurysm development in apolipoprotein E-deficient mice? Ann N Y Acad Sci 1085:151-60
Zhao, Lei; Pratico, Domenico; Rader, Daniel J et al. (2005) 12/15-Lipoxygenase gene disruption and vitamin E administration diminish atherosclerosis and oxidative stress in apolipoprotein E deficient mice through a final common pathway. Prostaglandins Other Lipid Mediat 78:185-93
Chinnici, Cinzia M; Yao, Yuemang; Ding, Tao et al. (2005) Absence of 12/15 lipoxygenase reduces brain oxidative stress in apolipoprotein E-deficient mice. Am J Pathol 167:1371-7
Anning, Peter B; Coles, Barbara; Bermudez-Fajardo, Alexandra et al. (2005) Elevated endothelial nitric oxide bioactivity and resistance to angiotensin-dependent hypertension in 12/15-lipoxygenase knockout mice. Am J Pathol 166:653-62
Tietge, Uwe J F; Pratico, Domenico; Ding, Tao et al. (2005) Macrophage-specific expression of group IIA sPLA2 results in accelerated atherogenesis by increasing oxidative stress. J Lipid Res 46:1604-14
Wang, Dairong; Wong, Dairong; Wang, Miao et al. (2005) Cardiovascular hazard and non-steroidal anti-inflammatory drugs. Curr Opin Pharmacol 5:204-10
Pratico, Domenico; Zhukareva, Victoria; Yao, Yuemang et al. (2004) 12/15-lipoxygenase is increased in Alzheimer's disease: possible involvement in brain oxidative stress. Am J Pathol 164:1655-62

Showing the most recent 10 out of 38 publications