Nox Isoforms and Vascular Cell Phenotype

Summary

Principal Investigator: John Keaney
Affiliation: University of Massachusetts Medical School
Country: USA
Abstract: Clinical manifestations of cardiovascular disease, such as heart attack, stroke, and congestive heart failure, are the number one cause of death in the developed world. Despite considerable interest in specific cardiovascular risk factors such as hypercholesterolemia, diabetes, and hypertension, data from the Framingham Heart Study indicate clearly the main determinant of incident cardiovascular disease is aging. Aged blood vessels are characterized by reduced control of antioxidant enzymes, an increased flux of reactive oxygen species, and vascular dysfunction. This flux of reactive oxygen species has proven to be a major determinant of vascular phenotype as a function of age, consistent with the "Free Radical Theory" of aging. This theory, originally proposed by Harman/1, pointed to the mitochondrion as the principal source of free radicals. However, there is now compelling evidence for multiple enzymatic sources of reactive oxygen species throughout blood vessels and particularly in the endothelium. Principle among these are the NADPH oxidase family of enzymes that are related to the classical neutrophil respiratory burst oxidase. We and others have found that endothelial cells contain two specific isoforms of the NADPH oxidase catalytic subunit (Nox);Nox2 and Nox4. The former is identical to the respiratory burst oxidase (GP91/phox, now Nox2), whereas the latter is novel. Considerable data indicate that excess vascular reactive oxygen species that are characteristic of vascular disease and aging are due, in part, from Nox enzymatic activity. Most investigation on Nox-derived reactive oxygen species and vascular disease has focused on Nox2. However, the role of Nox4 and how it differs with Nox2 with regard to vascular phenotype is not known. This is all the more problematic considering that Nox4 is the major Nox isoform in the vasculature. This proposal is designed to bridge this gap in knowledge and is based upon the hypothesis that reactive oxygen species produced by specific Nox isoforms is an important determinant of the maladaptive vascular phenotype that is characteristic of vascular disease and aging. The objective of this application, therefore, is to determine the role of specific Nox isoforms in controlling endothelial cell phenotype and elucidate the mechanisms involved. In order to achieve this objective, we will first characterize the NADPH oxidase catalytic subunit isoforms in endothelial cells with expect to their expression, subcellular localization, and subunit requirements. We will then use gain-of-function and loss-of-function strategies to determine the role of Nox isoforms in controlling endothelial cell phenotypes involving ROS such as NO bioactivity, adhesion molecule expression, proliferation, migration, and senescence. We will then go on to manipulate Nox4 expression in mice using stable siRNA expression or cell-specific Nox overexpression and examine the implications for vascular function and the response to arterial injury. Successful prosecution of these studies will provide mechanistic information on redox-mediated control of vascular cell phenotype and afford us the necessary insight to design new therapeutic strategies that focus on Nox-derived reactive oxygen species.
Funding Period: 2005-02-15 - 2010-01-31
more information: NIH RePORT

Top Publications

  1. pmc AMP-activated protein kinase: a stress-responsive kinase with implications for cardiovascular disease
    Chunying Li
    Division of Cardiovascular Medicine, Department of Medicine, University of Massachusetts Medical School, 55 Lake Avenue N, S3 855, Worcester, MA 01655, USA
    Curr Opin Pharmacol 10:111-5. 2010
  2. pmc Kynurenine is an endothelium-derived relaxing factor produced during inflammation
    Yutang Wang
    Centre for Vascular Research, School of Medical Sciences Pathology and Bosch Institute, Faculty of Medicine, University of Sydney, Sydney, Australia
    Nat Med 16:279-85. 2010
  3. pmc Chronic activation of AMP-activated protein kinase prevents 20-hydroxyeicosatetraenoic acid-induced endothelial dysfunction
    Natalie C Ward
    Cardiovascular Division, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
    Clin Exp Pharmacol Physiol 38:328-33. 2011
  4. ncbi YFP photoconversion revisited: confirmation of the CFP-like species
    Michael T Kirber
    Nat Methods 4:767-8. 2007
  5. pmc Regulation of ROS signal transduction by NADPH oxidase 4 localization
    Kai Chen
    Department of Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
    J Cell Biol 181:1129-39. 2008
  6. pmc Clinical correlates, heritability, and genetic linkage of circulating CD40 ligand in the Framingham Offspring Study
    John F Keaney
    Evans Memorial Department of Medicine, Boston University School of Medicine, Boston, MA, USA
    Am Heart J 156:1003-1009.e1. 2008
  7. pmc Downstream targets and intracellular compartmentalization in Nox signaling
    Kai Chen
    Division of Cardiovascular Medicine, Department of Medicine, University of Massachusetts Medical School Worcester, Massachusetts 01605, USA
    Antioxid Redox Signal 11:2467-80. 2009

Scientific Experts

  • Kai Chen
  • Natalie C Ward
  • John Keaney
  • Chunying Li
  • Yutang Wang
  • Michael T Kirber
  • Paul K Witting
  • Johannes Peter Stasch
  • Dechaboon Changsirivathanathamrong
  • Shane R Thomas
  • Roland Stocker
  • Nicholas H Hunt
  • David S Celermajer
  • Vimal Kapoor
  • Michael Hahn
  • Ben J Wu
  • Hanzhong Liu
  • Andrew L Mellor
  • Gavin McKenzie
  • Helen J Ball

Detail Information

Publications9

  1. pmc AMP-activated protein kinase: a stress-responsive kinase with implications for cardiovascular disease
    Chunying Li
    Division of Cardiovascular Medicine, Department of Medicine, University of Massachusetts Medical School, 55 Lake Avenue N, S3 855, Worcester, MA 01655, USA
    Curr Opin Pharmacol 10:111-5. 2010
    ..This enzyme represents an attractive therapeutic target for vascular disease treatment in the future...
  2. pmc Kynurenine is an endothelium-derived relaxing factor produced during inflammation
    Yutang Wang
    Centre for Vascular Research, School of Medical Sciences Pathology and Bosch Institute, Faculty of Medicine, University of Sydney, Sydney, Australia
    Nat Med 16:279-85. 2010
    ..Kynurenine administration decreased blood pressure in a dose-dependent manner in spontaneously hypertensive rats. Our results identify tryptophan metabolism by Ido as a new pathway contributing to the regulation of vascular tone...
  3. pmc Chronic activation of AMP-activated protein kinase prevents 20-hydroxyeicosatetraenoic acid-induced endothelial dysfunction
    Natalie C Ward
    Cardiovascular Division, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
    Clin Exp Pharmacol Physiol 38:328-33. 2011
    ..This provides a mechanism for reduced nitric oxide bioactivity and endothelial dysfunction in diseases with elevated 20-HETE levels, such as hypertension...
  4. ncbi YFP photoconversion revisited: confirmation of the CFP-like species
    Michael T Kirber
    Nat Methods 4:767-8. 2007
  5. pmc Regulation of ROS signal transduction by NADPH oxidase 4 localization
    Kai Chen
    Department of Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
    J Cell Biol 181:1129-39. 2008
    ..These data indicate that the specificity of intracellular ROS-mediated signal transduction may be modulated by the localization of Nox isoforms within specific subcellular compartments...
  6. pmc Clinical correlates, heritability, and genetic linkage of circulating CD40 ligand in the Framingham Offspring Study
    John F Keaney
    Evans Memorial Department of Medicine, Boston University School of Medicine, Boston, MA, USA
    Am Heart J 156:1003-1009.e1. 2008
    ..Circulating soluble CD40L (sCD40L) concentration predicts cardiovascular risk in selected patient samples. The purpose of this study was to determine the predictors of sCD40L in a large, community-based sample...
  7. pmc Downstream targets and intracellular compartmentalization in Nox signaling
    Kai Chen
    Division of Cardiovascular Medicine, Department of Medicine, University of Massachusetts Medical School Worcester, Massachusetts 01605, USA
    Antioxid Redox Signal 11:2467-80. 2009
    ..Herein we review recent data that link cellular NADPH oxidase enzymes to ROS signaling, with a particular focus on the mechanism(s) involved in achieving signaling specificity...