title: Acute O-GlcNAcylation prevents inflammation-induced vascular dysfunction.
abstract: Acute increases in cellular protein O-linked N-acetyl-glucosamine (O-GlcNAc) modification (O-GlcNAcylation) have been shown to have protective effects in the heart and vasculature. We hypothesized that d-glucosamine (d-GlcN) and Thiamet-G, two agents that increase protein O-GlcNAcylation via different mechanisms, inhibit TNF-α-induced oxidative stress and vascular dysfunction by suppressing inducible nitric oxide (NO) synthase (iNOS) expression. Rat aortic rings were incubated for 3h at 37°C with d-GlcN or its osmotic control l-glucose (l-Glc) or with Thiamet-G or its vehicle control (H(2)O) followed by the addition of TNF-α or vehicle (H(2)O) for 21 h. After incubation, rings were mounted in a myograph to assess arterial reactivity. Twenty-four hours of incubation of aortic rings with TNF-α resulted in 1) a hypocontractility to 60 mM K(+) solution and phenylephrine, 2) blunted endothelium-dependent relaxation responses to ACh and substance P, and 3) unaltered relaxing response to the Ca(2+) ionophore A-23187 and the NO donor sodium nitroprusside compared with aortic rings cultured in the absence of TNF-α. d-GlcN and Thiamet-G pretreatment suppressed the TNF-α-induced hypocontractility and endothelial dysfunction. Total protein O-GlcNAc levels were significantly higher in aortic segments treated with d-GlcN or Thiamet-G compared with controls. Expression of iNOS protein was increased in TNF-α-treated rings, and this was attenuated by pretreatment with either d-GlcN or Thiamet-G. Dense immunostaining for nitrotyrosylated proteins was detected in the endothelium and media of the aortic wall, suggesting enhanced peroxynitrite production by iNOS. These findings demonstrate that acute increases in protein O-GlcNAcylation prevent TNF-α-induced vascular dysfunction, at least in part, via suppression of iNOS expression.
authors: Vascular Biology and Hypertension Program, Division of Cardiovascular Disease, Department of Medicine, University of Alabama, Birmingham, Alabama 35294-0007, USA.
authors: Rob H P
authors: RH
authors: Hilgers
authors: Dongqi
authors: D
authors: Xing
authors: Kaizheng
authors: K
authors: Gong
authors: Yiu-Fai
authors: YF
authors: Chen
authors: John C
authors: JC
authors: Chatham
authors: Suzanne
authors: S
authors: Oparil
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism*; D000215:Acylation; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D001018:Aortic Diseases / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D009213:Myography; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D046509:Tissue Culture Techniques; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology; D001619:beta-N-Acetylhexosaminidases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D014409:Tumor Necrosis Factor-alpha; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; C110628:hexosaminidase C; D001619:beta-N-Acetylhexosaminidases; D000117:Acetylglucosamine