Nitric oxide (NO) is produced by endothelial NO synthase (eNOS) and plays a key role in maintaining vascular health and renal function. Chronic exposure to high glucose triggers oxidation of tetrahydrobiopterin (BH4), an essential eNOS cofactor, resulting in accumulation of dihydrobiopterin (BH2) in the vascular endothelium. During the initial period of Merit Award support, we discovered that BH2 binds eNOS with high avidity, replacing BH4 and switching the eNOS product from NO to superoxide. Studies suggest that BH2 binding to eNOS can initiate a pivotal feed-forward molecular cascade that drives oxidative stress and NO insufficiency in diabetic blood vessels, responsible for severe diabetic vascular complications that can lead to amputations, blindness, kidney failure and death. Research also demonstrates the efficacy of a novel pharmacological approach for disrupting the cascade of NO insufficiency and oxidative stress in diabetic blood vessels, utilizing agents that release NO via efficient reaction with superoxide (and/or derived oxidants). Remarkably, superoxide-dependent NO release is a property of the eNOS catalytic intermediate, N'?-hydroxyarginine (NOMA), an endogenous molecule that circulates in blood at 5-10 pM. By concurrently scavenging oxidants and releasing NO, administered NOMA can selectively target NO delivery to vascular sites of oxidative stress, increasing BH4:BH2 and restoring eNOS coupling and NO production. Indeed, chronic NOMA treatment of genetically-diabetic db/db prevented development of endothelial dysfunction, hypertension and NO insufficiency that othenwise occurred in vehicle-treated controls. NOMA (or a related hydroxyguanidine) could fill a major unmet clinical need, by providing targeted therapy for diabetic vasculapathies as a first-in-class superoxide-dependent NO-releasing agent. The overall goal of studies proposed during this Merit Award extension period is to enhance our biochemical understanding of the role of NO in diabetes and extend our assessment of NOHA for potential therapy of diabetic vasculopathies. This will include evaluation of NOHA pharmacokinetics, metabolism, reaction mechanisms, effects on metabolism and therapeutic benefit in rodent models of diabetes-impaired wound healing, angiogenesis and limb blood flow insufficiency. Studies will rely on new research approaches and assays, established during the initial Merit Award period - including a powerful LC/MS/MS platform for global untargeted metabolite profiling (to survey expression changes in thousands of molecules, 50 - 1000 m/z) and a proteomic approach for discovering nitrated proteins and sites that result from uncoupled eNOS and may contribute to vasculopathy.

Public Health Relevance

Insufficiency of endothelium-derived NO bioactivity is the basis for endothelial dysfunction in diabetic patients. Cardiovascular complications are the most common and devastating manifestation of diabetes, responsible for at least 77% of diabetic hospital admissions. Diminished NO is the apparent basis for diabetic vasculopathies that often result in amputations, blindness, kidney failure and death. This research seeks to evaluate a potential breakthrough pharmacological strategy and agent for therapy of diabetic vasculopthy.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HL087062-08
Application #
8613319
Study Section
Special Emphasis Panel (NSS)
Program Officer
Mcdonald, Cheryl
Project Start
2007-02-01
Project End
2017-01-31
Budget Start
2014-02-01
Budget End
2015-01-31
Support Year
8
Fiscal Year
2014
Total Cost
$380,250
Indirect Cost
$155,250
Name
Weill Medical College of Cornell University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
060217502
City
New York
State
NY
Country
United States
Zip Code
10065
Deeb, Ruba S; Walters, Matthew S; Strulovici-Barel, Yael et al. (2016) Smoking-Associated Disordering of the Airway Basal Stem/Progenitor Cell Metabotype. Am J Respir Cell Mol Biol 54:231-40
Suhre, Karsten; Schwartz, Joseph E; Sharma, Vijay K et al. (2016) Urine Metabolite Profiles Predictive of Human Kidney Allograft Status. J Am Soc Nephrol 27:626-36
Mitchell, Emma; Klein, Shifra L; Argyropoulos, Kimon V et al. (2016) Behavioural traits propagate across generations via segregated iterative-somatic and gametic epigenetic mechanisms. Nat Commun 7:11492
Hansler, Alex; Chen, Qiuying; Ma, Yuliang et al. (2016) Untargeted metabolite profiling reveals that nitric oxide bioynthesis is an endogenous modulator of carotenoid biosynthesis in Deinococcus radiodurans and is required for extreme ionizing radiation resistance. Arch Biochem Biophys 589:38-52
Akimova, Darya; Wlodarczyk, Bogdan J; Lin, Ying et al. (2016) Metabolite profiling of whole murine embryos reveals metabolic perturbations associated with maternal valproate-induced neural tube closure defects. Birth Defects Res A Clin Mol Teratol :
Granados-Principal, Sergio; Liu, Yi; Guevara, Maria L et al. (2015) Inhibition of iNOS as a novel effective targeted therapy against triple-negative breast cancer. Breast Cancer Res 17:25
Nuriel, Tal; Whitehouse, Julia; Ma, Yuliang et al. (2015) ANSID: A Solid-Phase Proteomic Approach for Identification and Relative Quantification of Aromatic Nitration Sites. Front Chem 3:70
Minton, Denise R; Fu, Leiping; Chen, Qiuying et al. (2015) Analyses of the transcriptome and metabolome demonstrate that HIF1α mediates altered tumor metabolism in clear cell renal cell carcinoma. PLoS One 10:e0120649
Chen, Qiuying; Deeb, Ruba S; Ma, Yuliang et al. (2015) Serum Metabolite Biomarkers Discriminate Healthy Smokers from COPD Smokers. PLoS One 10:e0143937
Hansler, Alex; Chen, Qiuying; Gray, Jason D et al. (2014) Untargeted metabolite profiling of murine embryos to reveal metabolic perturbations associated with neural tube closure defects. Birth Defects Res A Clin Mol Teratol 100:623-32

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