title: Adiponectin-induced endothelial nitric oxide synthase activation and nitric oxide production are mediated by APPL1 in endothelial cells.
abstract: Adiponectin protects the vascular system partly through stimulation of endothelial nitric oxide (NO) production and endothelium-dependent vasodilation. The current study investigated the role of two recently identified adiponectin receptors, AdipoR1 and -R2, and their downstream effectors in mediating the endothelium actions of adiponectin. In human umbilical vein endothelial cells, adiponectin-induced phosphorylation of endothelial NO synthase (eNOS) at Ser(1177) and NO production were abrogated when expression of AdipoR1 and -R2 were simultaneously suppressed. Proteomic analysis demonstrated that the cytoplasmic tails of both AdipoR1 and -R2 interacted with APPL1, an adaptor protein that contains a PH (pleckstrin homology) domain, a PTB (phosphotyrosine-binding) domain, and a Leucine zipper motif. Suppression of APPL1 expression by RNA interference significantly attenuated adiponectin-induced phosphorylation of AMP-activated protein kinase (AMPK) at Thr(172) and eNOS at Ser(1177), and the complex formation between eNOS and heat shock protein 90, resulting in a marked reduction of NO production. Adenovirus-mediated overexpression of a constitutively active version of AMPK reversed these changes. In db/db diabetic mice, both APPL1 expression and adiponectin-induced vasodilation were significantly decreased compared with their lean littermates. Taken together, these results suggest that APPL1 acts as a common downstream effector of AdipoR1 and -R2, mediating adiponectin-evoked endothelial NO production and endothelium-dependent vasodilation.
authors.affiliation: Department of Medicine, University of Hong Kong, Hong Kong, China.
authors.forename: Kenneth K Y
authors.initials: KK
authors.lastname: Cheng
authors.forename: Karen S L
authors.initials: KS
authors.lastname: Lam
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.forename: David
authors.initials: D
authors.lastname: Carling
authors.forename: Donghai
authors.initials: D
authors.lastname: Wu
authors.forename: Chiwai
authors.initials: C
authors.lastname: Wong
authors.forename: Aimin
authors.initials: A
authors.lastname: Xu
mesh_terms: D055372:AMP-Activated Protein Kinases; D048868:Adaptor Proteins, Signal Transducing; D052242:Adiponectin / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D005822:Genetic Vectors; D006801:Humans; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000187:drug effects / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014471:Umbilical Veins; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
chemical_list: C475418:ADIPOR1 protein, human; C475420:ADIPOR2 protein, human; C464801:APPL1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D052242:Adiponectin; D002352:Carrier Proteins; D009097:Multienzyme Complexes; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases