2-chlorohexadecanal derived from hypochlorite-modified high-density lipoprotein-associated plasmalogen is a natural inhibitor of endothelial nitric oxide biosynthesis.
OBJECTIVE
Myeloperoxidase, a heme enzyme that is present and active in human atherosclerotic lesions, provides a source for the generation of proinflammatory chlorinated reactants contributing to endothelial dysfunction. Modification of high-density lipoprotein (HDL) by hypochlorous acid/hypochlorite (HOCl/OCl-) [correction]-generated in vivo by the myeloperoxidase-hydrogen peroxide-chloride system of activated phagocytes-forms a proatherogenic lipoprotein particle that binds to and is internalized by endothelial cells.


RESULTS
Here we show that HDL, modified with physiologically relevant HOCl concentrations, attenuates the expression and activity of vasculoprotective endothelial nitric oxide synthase. HOCl-HDL promotes dislocalization of endothelial nitric oxide synthase from the plasma membrane and perinuclear location of human umbilical venous endothelial cells. We could identify 2-chlorohexadecanal as the active component mediating this inhibitory activity. This chlorinated fatty aldehyde is formed during HOCl-mediated oxidative cleavage of HDL-associated plasmalogen.


CONCLUSIONS
2-Chlorohexadecanal, produced by the myeloperoxidase-hydrogen peroxide-chloride system of activated phagocytes may act as a mediator of vascular injury associated with ischemia-reperfusion injury, glomerulosclerosis, and atherosclerosis.
Marsche
Gunther
G
Institute of Molecular Biology and Biochemistry, Medical University Graz, Austria.
Heller
Regine
R
Fauler
Günter
G
Kovacevic
Alenka
A
Nuszkowski
Alexander
A
Graier
Wolfgang
W
Sattler
Wolfgang
W
Malle
Ernst
E
D000447:Aldehydes / Q000378:metabolism*; D002460:Cell Line; D042783:Endothelial Cells / Q000201:enzymology / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006997:Hypochlorous Acid / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000378:metabolism*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III; D010955:Plasmalogens / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology / Q000201:enzymology / Q000378:metabolism
C432398:2-chlorohexadecanal; D000447:Aldehydes; D008075:Lipoproteins, HDL; D010955:Plasmalogens; D009569:Nitric Oxide; D006997:Hypochlorous Acid; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III