title: Integrin-linked kinase regulates vasomotor function by preventing endothelial nitric oxide synthase uncoupling: role in atherosclerosis.
abstract: BACKGROUND
  Atherosclerotic lesions develop in regions of disturbed flow, whereas laminar flow protects from atherogenesis; however, the mechanisms involved are not completely elucidated. Integrins are mechanosensors of shear stress in endothelial cells, and integrin-linked kinase (ILK) is important for blood vessel integrity and cardiovascular development.
  
  
  OBJECTIVE
  To explore the role of ILK in vascular function by studying conditionally ILK-deficient (cKO) mice and human atherosclerotic arteries.
  
  
  RESULTS
  ILK expression was detected in the endothelial cell layer of nonatherosclerotic vessels but was absent from the endothelium of atherosclerotic arteries. Live ultrasound imaging revealed that acetylcholine-mediated vasodilatation was impaired in cKO mice. These mice exhibited lowered agonist-induced nitric oxide synthase (NOS) activity and decreased cyclic guanosine monophosphate and nitrite production. ILK deletion caused endothelial NOS (eNOS) uncoupling, reflected in reduced tetrahydrobiopterin (BH4) levels, increased BH2 levels, decreased dihydrofolate reductase expression, and increased eNOS-dependent generation of superoxide accompanied by extensive vascular protein nitration. ILK reexpression prevented eNOS uncoupling in cKO cells, whereas superoxide formation was unaffected by ILK depletion in eNOS-KO cells, indicating eNOS as a primary source of superoxide anion. eNOS and ILK coimmunoprecipitated in aortic lysates from control animals, and eNOS-ILK-shock protein 90 interaction was detected in human normal mammary arteries but was absent from human atherosclerotic carotid arteries. eNOS-ILK interaction in endothelial cells was prevented by geldanamycin, suggesting heat shock protein 90 as a binding partner.
  
  
  CONCLUSIONS
  Our results identify ILK as a regulatory partner of eNOS in vivo that prevents eNOS uncoupling, and suggest ILK as a therapeutic target for prevention of endothelial dysfunction related to shear stress-induced vascular diseases.
authors.affiliation: National Center for Cardiovascular Research, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Herranz
authors.forename: Susana
authors.initials: S
authors.lastname: Marquez
authors.forename: Brenda
authors.initials: B
authors.lastname: Guijarro
authors.forename: Enrique
authors.initials: E
authors.lastname: Aracil
authors.forename: Clara
authors.initials: C
authors.lastname: Aicart-Ramos
authors.forename: Ignacio
authors.initials: I
authors.lastname: Rodriguez-Crespo
authors.forename: Isabel
authors.initials: I
authors.lastname: Serrano
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Puyol
authors.forename: Carlos
authors.initials: C
authors.lastname: Zaragoza
authors.forename: Marta
authors.initials: M
authors.lastname: Saura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001158:Arteries / Q000503:physiopathology*; D050197:Atherosclerosis / Q000503:physiopathology*; D002417:Cattle; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000502:physiology; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000502:physiology; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D018841:HSP90 Heat-Shock Proteins / Q000502:physiology; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology; D052250:Nitric Oxide Synthase Type III / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D014666:Vasomotor System / Q000502:physiology*; D000099200:Scaffold Protein ILK
chemical_list: D006152:Cyclic GMP; D018841:HSP90 Heat-Shock Proteins; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK