Catalytic consumption of nitric oxide by 12/15- lipoxygenase: Inhibition of monocyte soluble guanylate cyclase activation

doi:10.1073/pnas.141136098

Catalytic consumption of nitric oxide by 12/15- lipoxygenase: Inhibition of monocyte soluble guanylate cyclase activation

^*Wales Heart Research Institute, University of Wales College of Medicine, Cardiff CF14 4XN, United Kingdom; ^‡Departments of Anesthesiology, Biochemistry, and Molecular Genetics, Pathology and the Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35233; ^†Gonda Diabetes Center, City of Hope Medical Center, Duarte, CA 91010; ^§Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3US, United Kingdom; and ^¶Institute of Biochemistry, Humboldt University, Hessiche Strasse 3-4, Berlin, Germany

Edited by Louis J. Ignarro, University of California School of Medicine, Los Angeles, CA, and approved May 2, 2001 (received for review March 21, 2001)

Abstract

12/15-Lipoxygenase (LOX) activity is elevated in vascular diseases associated with impaired nitric oxide (^⋅NO) bioactivity, such as hypertension and atherosclerosis. In this study, primary porcine monocytes expressing 12/15-LOX, rat A10 smooth muscle cells transfected with murine 12/15-LOX, and purified porcine 12/15-LOX all consumed ^⋅NO in the presence of lipid substrate. Suppression of LOX diene conjugation by ^⋅NO was also found, although the lipid product profile was unchanged. ^⋅NO consumption by porcine monocytes was inhibited by the LOX inhibitor, eicosatetraynoic acid. Rates of arachidonate (AA)- or linoleate (LA)-dependent ^⋅NO depletion by porcine monocytes (2.68 ± 0.03 nmol ⋅ min⁻¹ ⋅ 10⁶ cells⁻¹ and 1.5 ± 0.25 nmol ⋅ min⁻¹ ⋅ 10⁶ cells⁻¹, respectively) were several-fold greater than rates of ^⋅NO generation by cytokine-activated macrophages (0.1–0.2 nmol ⋅ min⁻¹ ⋅ 10⁶ cells⁻¹) and LA-dependent ^⋅NO consumption by primary porcine monocytes inhibited ^⋅NO activation of soluble guanylate cyclase. These data indicate that catalytic ^⋅NO consumption by 12/15-LOX modulates monocyte ^⋅NO signaling and suggest that LOXs may contribute to vascular dysfunction not only by the bioactivity of their lipid products, but also by serving as catalytic sinks for ^⋅NO in the vasculature.

Footnotes

↵ ‖ To whom reprint requests should be addressed at: Wales Heart Research Institute, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, United Kingdom. E-mail: o-donnellvb{at}cardiff.ac.uk.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations:

LOX,

lipoxygenase;

⋅NO,

nitric oxide;

O2⨪,

superoxide;

HPETE,

hydroperoxyeicosatetraenoic acid;

HETE,

hydroxyeicosatetraenoic acid;

sGC,

soluble guanylate cyclase;

ETYA,

eicosatetraynoic acid;

AA,

arachidonate;

LA,

linoleate;

ang II,

angiotensin II;

RT,

reverse transcriptase;

DPI,

diphenylene iodonium;

oxyHb,

oxyhemoglobin