Cellular oxidative metabolism leads to the generation of reactive oxygen species (ROS). Antioxidant mechanisms have evolved to regulate the steady-state flux of ROS and minimize their cytotoxicity. The antioxidant potential of cells is largely governed by both low-molecular-weight reductants and by antioxidant enzymes. While the intracellular determinants of ROS flux by vascular cells have been well characterized in recent years, the extracellular determinants of ROS flux and their regulation are less well understood. For the last two cycles of this award, we have studied a key antioxidant enzyme that regulates extracellular peroxide flux, glutathione peroxidase-3 (GPx-3). We studied the biochemistry and molecular cell biology of this selenoprotein in order to understand its role in regulating the bioavailability of endothelial nitric oxide and in modulating platelet activation in the vasculature. While GPx-3 can effectively reduce both hydrogen peroxide and lipid peroxides to water and lipid alcohols, respectively, recent kinetic studies suggest that hydrogen peroxide is the preferred substrate. Because extracellular hydrogen peroxide can affect endothelial cell-surface receptor signaling (at low concentrations) and extracellular oxidant stress (at high concentrations), the factors that govern its production, molecular actions, and metabolic fates in the vasculature warrant study. The central hypothesis of this proposal is that GPx-3 is a principal determinant of extracellular hydrogen peroxide flux from the endothelial cell, and a key regulator of the transmembrane cycling and actions of hydrogen peroxide in the endothelial cell. To test this hypothesis, we propose three specific aims. We will first assess the role of GPx-3 in eliminating hydrogen peroxide and will examine the reductive cofactor(s) required for its optimal activity in the extracellular microenvironment of the endothelial cell. Second, we will determine the role of hydrogen peroxide in regulating the expression of GPx-3 at the transcriptional, posttranscriptional, and translational levels. Third, we will examine the interactions between GPx-3 and its intracellular counterpart GPx-1 on the transcellular metabolism and cycling of hydrogen peroxide, and its consequences for """"""""outside-in"""""""" and """"""""inside-out"""""""" signaling in endothelial cells. These studies should provide insight into the complex relationships among hydrogen peroxide flux, extracellular antioxidant potential, and cell signaling and oxidant stress in the endothelial cell. ? ? ?

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 #
5R37HL061795-11
Application #
7463615
Study Section
Vascular Cell and Molecular Biology Study Section (VCMB)
Program Officer
Fleg, Jerome
Project Start
1998-09-30
Project End
2012-08-31
Budget Start
2008-09-01
Budget End
2009-08-31
Support Year
11
Fiscal Year
2008
Total Cost
$437,500
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
02115
Libby, Peter; Loscalzo, Joseph; Ridker, Paul M et al. (2018) Inflammation, Immunity, and Infection in Atherothrombosis: JACC Review Topic of the Week. J Am Coll Cardiol 72:2071-2081
Yang, Jia-Shu; Hsu, Jia-Wei; Park, Seung-Yeol et al. (2018) GAPDH inhibits intracellular pathways during starvation for cellular energy homeostasis. Nature 561:263-267
Cranford, Jonathan P; O'Hara, Thomas J; Villongco, Christopher T et al. (2018) Efficient Computational Modeling of Human Ventricular Activation and Its Electrocardiographic Representation: A Sensitivity Study. Cardiovasc Eng Technol 9:447-467
Musri, Melina M; Coll-Bonfill, NĂºria; Maron, Bradley A et al. (2018) MicroRNA Dysregulation in Pulmonary Arteries from Chronic Obstructive Pulmonary Disease. Relationships with Vascular Remodeling. Am J Respir Cell Mol Biol 59:490-499
Wang, Rui-Sheng; Loscalzo, Joseph (2018) Network-Based Disease Module Discovery by a Novel Seed Connector Algorithm with Pathobiological Implications. J Mol Biol 430:2939-2950
Leopold, Jane A; Loscalzo, Joseph (2018) Emerging Role of Precision Medicine in Cardiovascular Disease. Circ Res 122:1302-1315
Samokhin, Andriy O; Stephens, Thomas; Wertheim, Bradley M et al. (2018) NEDD9 targets COL3A1 to promote endothelial fibrosis and pulmonary arterial hypertension. Sci Transl Med 10:
Cheng, Feixiong; Desai, Rishi J; Handy, Diane E et al. (2018) Network-based approach to prediction and population-based validation of in silico drug repurposing. Nat Commun 9:2691
Oldham, William M; Oliveira, Rudolf K F; Wang, Rui-Sheng et al. (2018) Network Analysis to Risk Stratify Patients With Exercise Intolerance. Circ Res 122:864-876
Pang, Paul; Abbott, Molly; Abdi, Malyun et al. (2018) Pre-clinical model of severe glutathione peroxidase-3 deficiency and chronic kidney disease results in coronary artery thrombosis and depressed left ventricular function. Nephrol Dial Transplant 33:923-934

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