Human atherosclerotic intima and blood of patients with established coronary artery disease contain high density lipoprotein damaged by reactive nitrogen species.
High density lipoprotein (HDL) is the major carrier of lipid hydroperoxides in plasma, but it is not yet established whether HDL proteins are damaged by reactive nitrogen species in the circulation or artery wall. One pathway that generates such species involves myeloperoxidase (MPO), a major constituent of artery wall macrophages. Another pathway involves peroxynitrite, a potent oxidant generated in the reaction of nitric oxide with superoxide. Both MPO and peroxynitrite produce 3-nitrotyrosine in vitro. To investigate the involvement of reactive nitrogen species in atherogenesis, we quantified 3-nitrotyrosine levels in HDL in vivo. The mean level of 3-nitrotyrosine in HDL isolated from human aortic atherosclerotic intima was 6-fold higher (619 +/- 178 micromol/mol Tyr) than that in circulating HDL (104 +/- 11 micromol/mol Tyr; p < 0.01). Immunohistochemical studies demonstrated striking colocalization of MPO with epitopes reactive with an antibody to 3-nitrotyrosine. However, there was no significant correlation between the levels of 3-chlorotyrosine, a specific product of MPO, and those of 3-nitrotyrosine in lesion HDL. We also detected 3-nitrotyrosine in circulating HDL, and linear regression analysis demonstrated a strong correlation between the levels of 3-chlorotyrosine and levels of 3-nitrotyrosine. These observations suggest that MPO promotes the formation of 3-chlorotyrosine and 3-nitrotyrosine in circulating HDL but that other pathways also produce 3-nitrotyrosine in atherosclerotic tissue. Levels of HDL isolated from plasma of patients with established coronary artery disease contained twice as much 3-nitrotyrosine as HDL from plasma of healthy subjects, suggesting that nitrated HDL might be a marker for clinically significant vascular disease. The detection of 3-nitrotyrosine in HDL raises the possibility that reactive nitrogen species derived from nitric oxide might promote atherogenesis. Thus, nitrated HDL might represent a previously unsuspected link between nitrosative stress, atherosclerosis, and inflammation.
Pennathur
Subramaniam
S
Department of Medicine, School of Medicine, University of Washington, Seattle, Washington 98195, USA.
Bergt
Constanze
C
Shao
Baohai
B
Byun
Jaeman
J
Kassim
Sean Y
SY
Singh
Pragya
P
Green
Pattie S
PS
McDonald
Thomas O
TO
Brunzell
John
J
Chait
Alan
A
Oram
John F
JF
O'brien
Kevin
K
Geary
Randolph L
RL
Heinecke
Jay W
JW
D001158:Arteries / Q000473:pathology; D001161:Arteriosclerosis / Q000473:pathology*; D003324:Coronary Artery Disease / Q000097:blood* / Q000473:pathology*; D003331:Coronary Vessels / Q000378:metabolism / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D000939:Epitopes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation; D008054:Lipid Peroxides / Q000737:chemistry; D008075:Lipoproteins, HDL / Q000097:blood* / Q000737:chemistry*; D013058:Mass Spectrometry; D009569:Nitric Oxide / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000378:metabolism; D009195:Peroxidase / Q000737:chemistry / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000737:chemistry; D026361:Reactive Nitrogen Species; D013654:Taurine / Q000737:chemistry; D013997:Time Factors; D017539:Tunica Intima / Q000473:pathology*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry
D000939:Epitopes; D008054:Lipid Peroxides; D008075:Lipoproteins, HDL; D026361:Reactive Nitrogen Species; D030421:Peroxynitrous Acid; D013654:Taurine; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D009195:Peroxidase; D009584:Nitrogen; D010100:Oxygen; C087259:3-chlorotyrosine