title: Molecular mechanisms of activation of endothelial nitric oxide synthase mediated by transient receptor potential vanilloid type 1.
abstract: OBJECTIVE
  We investigated the molecular mechanism underlying the role of transient receptor potential vanilloid type 1 (TRPV1), a Ca(2+)-permeable non-selective cation channel, in the activation of endothelial nitric oxide (NO) synthase (eNOS) in endothelial cells (ECs) and mice.
  
  
  RESULTS
  In ECs, TRPV1 ligands (evodiamine or capsaicin) promoted NO production, eNOS phosphorylation, and the formation of a TRPV1-eNOS complex, which were all abrogated by the TRPV1 antagonist capsazepine. TRPV1 ligands promoted the phosphorylation of Akt, calmodulin-dependent protein kinase II (CaMKII) and TRPV1, and increased the formation of a TRPV1-Akt-CaMKII complex. Removal of extracellular Ca(2+) abolished the ligand-induced increase in the phosphorylation of Akt and CaMKII, formation of a TRPV1-eNOS complex, and eNOS activation. Inhibition of PI3K and CaMKII suppressed the ligand-induced increase in TRPV1 phosphorylation, formation of a TRPV1-eNOS complex, and eNOS activation. TRPV1 activation increased the phosphorylation of Akt, CaMKII, and eNOS in the aortas of wild-type mice but failed to activate eNOS in TRPV1-deficient aortas. Additionally, TRPV1 ligand-induced angiogenesis was diminished in eNOS- or TRPV1-deficient mice. When compared with apolipoprotein E (ApoE)-deficient mice, ApoE/TRPV1-double-knockout mice displayed reduced phosphorylation of eNOS, Akt, and CaMKII in aortas but worsened atherosclerotic lesions.
  
  
  CONCLUSIONS
  TRPV1 activation in ECs may trigger Ca(2+)-dependent PI3K/Akt/CaMKII signalling, which leads to enhanced phosphorylation of TRPV1, increased TRPV1-eNOS complex formation, eNOS activation and, ultimately, NO production.
authors.affiliation: Department of Physiology, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Li-Chieh
authors.initials: LC
authors.lastname: Ching
authors.forename: Yu Ru
authors.initials: YR
authors.lastname: Kou
authors.forename: Song-Kun
authors.initials: SK
authors.lastname: Shyue
authors.forename: Kuo-Hui
authors.initials: KH
authors.lastname: Su
authors.forename: Jeng
authors.initials: J
authors.lastname: Wei
authors.forename: Li-Ching
authors.initials: LC
authors.lastname: Cheng
authors.forename: Yuan-Bin
authors.initials: YB
authors.lastname: Yu
authors.forename: Ching-Chian
authors.initials: CC
authors.lastname: Pan
authors.forename: Tzong-Shyuan
authors.initials: TS
authors.lastname: Lee
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism; D050197:Atherosclerosis / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D002211:Capsaicin / Q000031:analogs & derivatives / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D034622:RNA Interference; D015398:Signal Transduction; D050916:TRPV Cation Channels / Q000172:deficiency / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection
chemical_list: D001057:Apolipoproteins E; D011799:Quinazolines; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C493921:TRPV1 protein, mouse; D009569:Nitric Oxide; C049639:evodiamine; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; C071423:capsazepine; D002211:Capsaicin