title: Adaptive induction of NF-E2-related factor-2-driven antioxidant genes in endothelial cells in response to hyperglycemia.
abstract: Hyperglycemia in diabetes mellitus promotes oxidative stress in endothelial cells, which contributes to development of cardiovascular diseases. Nuclear factor erythroid 2-related factor-2 (Nrf2) is a transcription factor activated by oxidative stress that regulates expression of numerous reactive oxygen species (ROS) detoxifying and antioxidant genes. This study was designed to elucidate the homeostatic role of adaptive induction of Nrf2-driven free radical detoxification mechanisms in endothelial protection under diabetic conditions. Using a Nrf2/antioxidant response element (ARE)-driven luciferase reporter gene assay we found that in a cultured coronary arterial endothelial cell model hyperglycemia (10-30 mmol/l glucose) significantly increases transcriptional activity of Nrf2 and upregulates the expression of the Nrf2 target genes NQO1, GCLC, and HMOX1. These effects of high glucose were significantly attenuated by small interfering RNA (siRNA) downregulation of Nrf2 or overexpression of Keap-1, which inactivates Nrf2. High-glucose-induced upregulation of NQO1, GCLC, and HMOX1 was also prevented by pretreatment with polyethylene glycol (PEG)-catalase or N-acetylcysteine, whereas administration of H(2)O(2) mimicked the effect of high glucose. To test the effects of metabolic stress in vivo, Nrf2(+/+) and Nrf2(-/-) mice were fed a high-fat diet (HFD). HFD elicited significant increases in mRNA expression of Gclc and Hmox1 in aortas of Nrf2(+/+) mice, but not Nrf2(-/-) mice, compared with respective standard diet-fed control mice. Additionally, HFD-induced increases in vascular ROS levels were significantly greater in Nrf2(-/-) than Nrf2(+/+) mice. HFD-induced endothelial dysfunction was more severe in Nrf2(-/-) mice, as shown by the significantly diminished acetylcholine-induced relaxation of aorta of these animals compared with HFD-fed Nrf2(+/+) mice. Our results suggest that adaptive activation of the Nrf2/ARE pathway confers endothelial protection under diabetic conditions.
authors.affiliation: Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, 73104, USA. zoltan-ungvari@ouhsc.edu
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Ungvari
authors.forename: Lora
authors.initials: L
authors.lastname: Bailey-Downs
authors.forename: Tripti
authors.initials: T
authors.lastname: Gautam
authors.forename: Rosario
authors.initials: R
authors.lastname: Jimenez
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Losonczy
authors.forename: Cuihua
authors.initials: C
authors.lastname: Zhang
authors.forename: Praveen
authors.initials: P
authors.lastname: Ballabh
authors.forename: Fabio A
authors.initials: FA
authors.lastname: Recchia
authors.forename: Donald C
authors.initials: DC
authors.lastname: Wilkerson
authors.forename: William E
authors.initials: WE
authors.lastname: Sonntag
authors.forename: Kevin
authors.initials: K
authors.lastname: Pearson
authors.forename: Rafael
authors.initials: R
authors.lastname: de Cabo
authors.forename: Anna
authors.initials: A
authors.lastname: Csiszar
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000222:Adaptation, Physiological; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001011:Aorta / Q000737:chemistry / Q000378:metabolism; D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics; D004041:Dietary Fats / Q000378:metabolism / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism; D005786:Gene Expression Regulation; D005721:Glutamate-Cysteine Ligase / Q000235:genetics; D051547:Heme Oxygenase-1 / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006943:Hyperglycemia / Q000378:metabolism*; D000072019:Kelch-Like ECH-Associated Protein 1; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008813:Mice, Inbred ICR; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000975:Antioxidants; D003598:Cytoskeletal Proteins; D004041:Dietary Fats; C117301:Keap1 protein, mouse; D000072019:Kelch-Like ECH-Associated Protein 1; D008565:Membrane Proteins; D051267:NF-E2-Related Factor 2; D017382:Reactive Oxygen Species; C070295:catalase-polyethylene glycol; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; D002374:Catalase; D051547:Heme Oxygenase-1; C496542:Hmox1 protein, mouse; D016660:NAD(P)H Dehydrogenase (Quinone); C491732:Nqo1 protein, mouse; D005721:Glutamate-Cysteine Ligase; D000111:Acetylcysteine