Modification induced by homocysteine and low-density lipoprotein on human aortic endothelial cells: an in vitro study.
The aim of the present study was to investigate the effect exerted by low-density lipoprotein (LDL) modified by homocysteine (Hcy)-thiolactone (Hcy-LDL) on functional properties on human endothelial cells. Hcy-thiolactone, a reactive product formed in human cells from enzymatic conversion of Hcy, was hypothesized to play an important role in Hcy-induced vascular damages. Using endothelial cultured cells [human aortic endothelial cells (HAEC)] as cellular model, we evaluated nitric oxide (NO) production, cytoplasmic Ca(2+) levels, Na(+)/K(+)-ATPase activity, and peroxynitrite production in cells incubated in the presence of control LDL or Hcy-LDL. Homocysteinylation of LDL was carried out by incubation of LDL, isolated from plasma of healthy subjects, with 100 microm Hcy-thiolactone. A significant increase in cytoplasmic Ca(2+) levels and peroxynitrite production and a decrease in Na(+)/K(+)-ATPase and NO production in HAEC incubated with Hcy-LDL compared with HAEC incubated with control LDL were observed. Moreover, a positive correlation was found between Na(+)/K(+)-ATPase activity and cytoplasmic Ca(2+) content and between peroxynitrite activity and cytoplasmic Ca(2+) content. In conclusion, our results demonstrated that LDL homocysteinylated in vitro induced alterations of functional properties and NO metabolism of human endothelial cells.
Vignini
A
A
Institute of Biochemistry, Università Politecnica delle Marche, Via P. Ranieri 65, 60131 Ancona, Italy.
Nanetti
L
L
Bacchetti
T
T
Ferretti
G
G
Curatola
G
G
Mazzanti
L
L
D000328:Adult; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000096:biosynthesis; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D008077:Lipoproteins, LDL; D006710:Homocysteine; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; C007957:homocysteine thiolactone; D019001:Nitric Oxide Synthase; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium