NAD(P)H oxidase participates in the signaling events in high glucose-induced proliferation of vascular smooth muscle cells.
Reactive oxygen species (ROS) have been implicated in the pathogenesis of vascular dysfunction in diabetes mellitus, and NAD(P)H oxidase is known as the most important source of ROS in the vasculatures. To determine whether NAD(P)H oxidase is a major participant in the critical intermediary signaling events in high glucose (HG, 25 mM)-induced proliferation of vascular smooth muscle cells (VSMC), we investigated in explanted aortic VSMC from rats the role of NAD(P)H oxidase on the HG-related cellular proliferation and superoxide production. VSMC under HG condition had increased proliferative capacity that was inhibited by tiron (1 mM), a cell membrane permeable superoxide scavenger, but not by SOD, which is not permeable to cell membrane. The nitroblue tetrazolium staining in the HG-exposed VSMC was more prominent than that of VSMC under normal glucose (5.5 mM) condition, which was significantly inhibited by DPI (10 microM), an NAD(P)H oxidase inhibitor, but not by inhibitors for other oxidases such as NADH dehydrogenase, xanthine oxidase, and nitric oxide synthase. In the VSMC under HG condition, the enhanced NAD(P)H oxidase activity with increased membrane translocation of Rac1 was observed, but the protein expression of p22phox and gp91phox was not increased. These data suggest that HG-induced changes in VSMC proliferation are related to the intracellular production of superoxide through enhanced activity of NAD(P)H oxidase.
Lee
Hyun Seung
HS
Department of Pharmacology and Internal Medicine, College of Medicine, Pusan National University, 10 Ami-Dong 1-Ga, Seo-Gu, Busan 602-739, South Korea.
Son
Seok Man
SM
Kim
Yong Ki
YK
Hong
Ki Whan
KW
Kim
Chi Dae
CD
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D026901:Membrane Transport Proteins; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects; D009252:NADPH Dehydrogenase / Q000096:biosynthesis; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009580:Nitroblue Tetrazolium; D010750:Phosphoproteins / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism; D014178:Translocation, Genetic; D020830:rac1 GTP-Binding Protein / Q000235:genetics
D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; D013481:Superoxides; D009580:Nitroblue Tetrazolium; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C086986:CYBA protein, human; D009252:NADPH Dehydrogenase; D020830:rac1 GTP-Binding Protein; D005947:Glucose