title: p22phox C242T Single-Nucleotide Polymorphism Inhibits Inflammatory Oxidative Damage to Endothelial Cells and Vessels.
abstract: The NADPH oxidase, by generating reactive oxygen species, is involved in the pathophysiology of many cardiovascular diseases and represents a therapeutic target for the development of novel drugs. A single-nucleotide polymorphism, C242T of the p22(phox) subunit of NADPH oxidase, has been reported to be negatively associated with coronary heart disease and may predict disease prevalence. However, the underlying mechanisms remain unknown.
  
  
  
  With the use of computer molecular modeling, we discovered that C242T single-nucleotide polymorphism causes significant structural changes in the extracellular loop of p22(phox) and reduces its interaction stability with Nox2 subunit. Gene transfection of human pulmonary microvascular endothelial cells showed that C242T p22(phox) significantly reduced Nox2 expression but had no significant effect on basal endothelial O2 (.-) production or the expression of Nox1 and Nox4. When cells were stimulated with tumor necrosis factor-α (or high glucose), C242T p22(phox) significantly inhibited tumor necrosis factor-α-induced Nox2 maturation, O2 (.-) production, mitogen-activated protein kinases and nuclear factor κB activation, and inflammation (all P<0.05). These C242T effects were further confirmed using p22(phox) short-hairpin RNA-engineered HeLa cells and Nox2(-/-) coronary microvascular endothelial cells. Clinical significance was investigated by using saphenous vein segments from non-coronary heart disease subjects after phlebotomies. TT (C242T) allele was common (prevalence of ≈22%) and, in comparison with CC, veins bearing TT allele had significantly lower levels of Nox2 expression and O2 (.-) generation in response to high-glucose challenge.
  
  
  
  C242T single-nucleotide polymorphism causes p22(phox) structural changes that inhibit endothelial Nox2 activation and oxidative response to tumor necrosis factor-α or high-glucose stimulation. C242T single-nucleotide polymorphism may represent a natural protective mechanism against inflammatory cardiovascular diseases.
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.).
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Meijles
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.).
authors.forename: Lampson M
authors.initials: LM
authors.lastname: Fan
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.).
authors.forename: Maziah M
authors.initials: MM
authors.lastname: Ghazaly
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.).
authors.forename: Brendan
authors.initials: B
authors.lastname: Howlin
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.).
authors.forename: Martin
authors.initials: M
authors.lastname: Krönke
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.).
authors.forename: Gavin
authors.initials: G
authors.lastname: Brooks
authors.affiliation: From Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, UK (D.N.M., G.B., J.-M.L.); Faculty of Engineering and Physical Sciences, University of Surrey, UK (D.N.M., M.M.G., B.H.); Department of Cardiology, Royal Berkshire Hospital, UK (L.M.F.); and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany (M.K.). jian-mei.li@reading.ac.uk.
authors.forename: Jian-Mei
authors.initials: JM
authors.lastname: Li
mesh_terms: D000818:Animals; D042783:Endothelial Cells / Q000201:enzymology* / Q000473:pathology; D006367:HeLa Cells; D006801:Humans; D007249:Inflammation / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D017382:Reactive Oxygen Species / Q000378:metabolism; D014652:Vascular Diseases / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology
chemical_list: D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C086986:CYBA protein, human
keywords: NADPH oxidase; blood vessels; endothelium; genetics; inflammation; structure