Acute O-GlcNAcylation prevents inflammation-induced vascular dysfunction

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 303; no. 5; pp. H513 - H522
• Main Authors: Hilgers, Rob H P, Xing, Dongqi, Gong, Kaizheng, Chen, Yiu-Fai, Chatham, John C, Oparil, Suzanne
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.09.2012
• Subjects: Acetylglucosamine - metabolism; Acylation; Animals; Aorta, Thoracic - drug effects; Aorta, Thoracic - immunology; Aorta, Thoracic - metabolism; Aorta, Thoracic - physiopathology; Aortic Diseases - immunology; Aortic Diseases - metabolism; Aortic Diseases - physiopathology; Aortic Diseases - prevention & control; beta-N-Acetylhexosaminidases - antagonists & inhibitors; beta-N-Acetylhexosaminidases - metabolism; Circulatory system; Dose-Response Relationship, Drug; Enzyme Inhibitors - pharmacology; Gene expression; Heart; Immunohistochemistry; Inflammation - immunology; Inflammation - metabolism; Inflammation - physiopathology; Inflammation Mediators - metabolism; Male; Myography; Nitric Oxide Synthase Type II - metabolism; Oxidative Stress; Peroxynitrous Acid - metabolism; Protein Processing, Post-Translational; Proteins; Rats; Rats, Sprague-Dawley; Time Factors; Tissue Culture Techniques; Tumor Necrosis Factor-alpha - metabolism; Tyrosine - analogs & derivatives; Tyrosine - metabolism; Vascular Biology and Microcirculation; Vasoconstriction - drug effects; Vasoconstrictor Agents - pharmacology; Vasodilation - drug effects; Vasodilator Agents - pharmacology
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.01175.2011

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.