title: Role of ERK1/2 activation and nNOS uncoupling on endothelial dysfunction induced by lysophosphatidylcholine.
abstract: Lysophosphatidylcholine (LPC) - a main component of oxidized LDL - is involved in endothelial dysfunction that precedes atherosclerosis, with an increased superoxide anions and a reduced NO production via endothelial NO synthase (eNOS) uncoupling. However, there is no evidence about the mechanisms involved in neuronal NOS (nNOS) uncoupling. Extracellular signal-regulated kinase (ERK) is related to the control of NO production and inflammatory gene transcription activation in atherosclerosis. Our aim was to investigate the role of nNOS/ERK1/2 pathway on endothelial dysfunction induced by LPC, in mouse aorta and human endothelial cells.
  
  
  
  Thoracic aorta from wild type mice was used to perform vascular reactivity studies in the presence or absence of LPC. Human endothelial cells were used to investigate the effect of LPC on expression of nNOS and his products NO and H2O2.
  
  
  
  LPC reduced acetylcholine (ACh)-induced vasodilation in mouse aorta (EmaxCT/LPC= ∼95 ± 2/62 ± 3%, p = 0.0004) and increased phenylephrine-induced vasoconstriction (EmaxCT/LPC= ∼4 ± 0,1/6 ± 0,1 mN/mm, p = 0.0002), with a reduction in NO (fluorescence intensityCT/LPC= 91 ± 3/62±2 × 103, p = 0.0002) and H2O2(fluorescence intensityCT/LPC= ∼16 ± 0,8/10 ± 0,7 × 103, p = 0.0041) production evocated by ACh. An inhibition of nNOS by TRIM (EmaxCT/CT+TRIM= ∼93 ± 1/43 ± 3%, p = 0,0048; EmaxLPC/LPC+TRIM= ∼62 ± 3/65 ± 3%) or H2O2degradation by catalase (EmaxCT/CT+cat= ∼93 ± 1/46 ± 2%, p < 0,001; EmaxLPC/LPC+cat= ∼62,8 ± 3,2/60,5 ± 4,7%) reduced the relaxation in the control but not in LPC group. PD98059, an ERK1/2 inhibitor, abolished the increase in vasoconstriction in LPC-treated vessels (EmaxLPC/LPC+PD= ∼6 ± 0,1/3 ± 0,1 mN/mm, p = 0.0001). LPC also reduced the dimer/monomer proportion and increased nNOSser852phosphorylation.
  
  
  
  LPC induced nNOS uncoupling and nNOSSer852phosphorylation, reduced NO and H2O2production and improved superoxide production by modulating ERK1/2 activity in human and murine endothelial cells.
authors.affiliation: Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Gianne P
authors.initials: GP
authors.lastname: Campos-Mota
authors.affiliation: Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Navia-Pelaez
authors.affiliation: Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Jessica Cristina
authors.initials: JC
authors.lastname: Araujo-Souza
authors.affiliation: Laboratory of Hemodynamics and Cardiovascular Technology, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, BM 5128 Station 17, CH-1015 Lausanne, Switzerland.
authors.forename: Nikos
authors.initials: N
authors.lastname: Stergiopulos
authors.affiliation: Laboratory of Vascular Biology, Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil. Electronic address: capettini@icb.ufmg.br.
authors.forename: Luciano S A
authors.initials: LSA
authors.lastname: Capettini
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D004789:Enzyme Activation; D006861:Hydrogen Peroxide / Q000378:metabolism; D066298:In Vitro Techniques; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D008297:Male; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D010766:Phosphorylation; D015398:Signal Transduction / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D008244:Lysophosphatidylcholines; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D013481:Superoxides; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; C496320:NOS1 protein, human; D052248:Nitric Oxide Synthase Type I; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3
keywords: ERK1/2; Endothelial dysfunction; Lysophosphatidylcholine; nNOS uncoupling