title: Glycated high-density lipoprotein regulates reactive oxygen species and reactive nitrogen species in endothelial cells.
abstract: Nonenzymatic glycosylation of plasma proteins may contribute to the excess risk of developing atherosclerosis in patients with diabetes mellitus. Although it is believed that high-density lipoprotein (HDL) is glycosylated at an increased level in diabetic individuals, little is known about a possible linkage between glycated HDL and endothelial dysfunction in diabetes. To clarify whether glucose-modified HDL affects the function of endothelial cells, we first examined herein the level of H(2)O(2) generation from cultured human aortic endothelial cells (HAECs) exposed to a glycated oxidized HDL (gly-ox-HDL) prepared in vitro. Incubation for 48 hours with 100 microg/mL of gly-ox-HDL induced significant release of H(2)O(2) from cells and gly-ox-HDL-induced H(2)O(2) formation was inhibited in the presence of diphenyleneiodonium, an inhibitor of NADPH oxidase. In addition, stimulation of HAECs with gly-ox-HDL for 48 hours elicited a marked downregulation of catalase and Cu(2+), Zn(2+)-superoxide dismutase (CuZn-SOD), suggesting H(2)O(2) formation by gly-ox-HDL to be due to a disturbance involving oxidant and antioxidant enzymes in the cells. Treatment of HAECs with gly-ox-HDL attenuated the expression of endothelial nitric oxide synthase (eNOS), but not inducible nitric oxide synthase (iNOS), and this was followed by decreased production of nitric oxide (NO) by the cells. Furthermore, in vitro experiments with glycated HDL (gly-HDL) in the presence of 2 mmol/L EDTA and Cu(2+)-oxidized HDL suggested the effect of gly-HDL on endothelial function to be possibly potentiated by additional oxidative modification. Taking all of the above findings together, gly-ox-HDL may lead to the deterioration of vascular function through altered production of reactive oxygen species and reactive nitrogen species in endothelial cells.
authors.affiliation: Department of Biochemistry, Saitama Medical School, Moroyama, Saitama, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Takanori
authors.initials: T
authors.lastname: Nakajima
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Iwao
authors.initials: I
authors.lastname: Koyama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hokari
authors.forename: Ikuo
authors.initials: I
authors.lastname: Inoue
authors.forename: Shin-ichiroh
authors.initials: S
authors.lastname: Kawai
authors.forename: Hiroji
authors.initials: H
authors.lastname: Shimomura
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Katayama
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
authors.forename: Tsugikazu
authors.initials: T
authors.lastname: Komoda
mesh_terms: D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000378:metabolism / Q000494:pharmacology*; D010084:Oxidation-Reduction; D011489:Protein Denaturation; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D008075:Lipoproteins, HDL; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase