title: Mitochondrial redox plays a critical role in the paradoxical effects of NAPDH oxidase-derived ROS on coronary endothelium.
abstract: There are conflicting reports on the role of reactive oxygen species (ROS) i.e. beneficial vs. harmful, in vascular endothelium. Here, we aim to examine whether duration of exposure to ROS and/or subcellular ROS levels are responsible for the apparently paradoxical effects of oxidants on endothelium.
  
  
  
  We have recently generated binary (Tet-ON/OFF) conditional transgenic mice (Tet-Nox2:VE-Cad-tTA) that can induce 1.8 ± 0.42-fold increase in NADPH oxidase (NOX)-derived ROS specifically in vascular endothelium upon withdrawal of tetracycline from the drinking water. Animals were divided in two groups: one exposed to high endogenous ROS levels for 8 weeks (short-term) and the other for 20 weeks (long-term). Using endothelial cells (EC) isolated from mouse hearts (MHEC), we demonstrate that both short-term and long-term increase in NOX-ROS induced AMPK-mediated activation of eNOS. Interestingly, although endothelium-dependent nitric oxide (NO)-mediated coronary vasodilation was significantly increased after short-term increase in NOX-ROS, coronary vasodilation was drastically reduced after long-term increase in ROS. We also show that short-term ROS increase induced proliferation in EC and angiogenic sprouting in the aorta. In contrast, long-term increase in cytosolic ROS resulted in nitrotyrosine-mediated inactivation of mitochondrial (mito) antioxidant MnSOD, increase in mito-ROS, loss of mitochondrial membrane potential (Δψm), decreased EC proliferation and angiogenesis.
  
  
  
  The findings suggest that NOX-derived ROS results in increased mito-ROS. Whereas short-term increase in mito-ROS was counteracted by MnSOD, long-term increase in ROS resulted in nitrotyrosine-mediated inactivation of MnSOD, leading to unchecked increase in mito-ROS and loss of Δψm followed by inhibition of endothelial function and proliferation.
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Ehtesham
authors.initials: E
authors.lastname: Shafique
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Anali
authors.initials: A
authors.lastname: Torina
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Karla
authors.initials: K
authors.lastname: Reichert
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Colantuono
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Nasifa
authors.initials: N
authors.lastname: Nur
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Khawaja
authors.initials: K
authors.lastname: Zeeshan
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Vani
authors.initials: V
authors.lastname: Ravichandran
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.|Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02903, USA.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.|Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02903, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Feng
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.
authors.forename: Khawaja
authors.initials: K
authors.lastname: Zeeshan
authors.affiliation: Imclone, 180 Varick St, New York, NY 10014, USA.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Benjamin
authors.affiliation: University of Iowa Carver School of Medicine, Iowa, IA, USA.
authors.forename: Kaikobad
authors.initials: K
authors.lastname: Irani
authors.affiliation: Providence VA Medical Center, Providence, RI, USA.|Brown University, Providence, RI, USA.
authors.forename: Elizabeth O
authors.initials: EO
authors.lastname: Harrington
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA.|Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02903, USA.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Sellke
authors.affiliation: Cardiovascular Research Center, Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, 1 Hoppin St, Providence, RI 02903, USA; ruhul_abid@brown.edu.|Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02903, USA.|Brown University, Providence, RI, USA.
authors.forename: Md Ruhul
authors.initials: MR
authors.lastname: Abid
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D043925:Angiogenesis Inducing Agents / Q000494:pharmacology; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000187:drug effects / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation; D005838:Genotype; D066298:In Vitro Techniques; D053078:Membrane Potential, Mitochondrial; D008822:Mice, Transgenic; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010084:Oxidation-Reduction; D010641:Phenotype; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology; D000099152:Cadherin 5
chemical_list: D055372:AMP-Activated Protein Kinases; D043925:Angiogenesis Inducing Agents; D015703:Antigens, CD; D015820:Cadherins; D019255:NADPH Oxidases; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D014443:Tyrosine; D014665:Vasodilator Agents; D000099152:Cadherin 5; C002744:3-nitrotyrosine; C496315:Nos3 protein, mouse
keywords: Endothelium • Signal transduction • Nitric oxide • Reactive oxygen species • NADPH oxidase