title: Grb-2-associated binder 1 (Gab1) regulates postnatal ischemic and VEGF-induced angiogenesis through the protein kinase A-endothelial NOS pathway.
abstract: The intracellular signaling mechanisms underlying postnatal angiogenesis are incompletely understood. Herein we show that Grb-2-associated binder 1 (Gab1) plays a critical role in ischemic and VEGF-induced angiogenesis. Endothelium-specific Gab1 KO (EGKO) mice displayed impaired angiogenesis in the ischemic hindlimb despite normal induction of VEGF expression. Matrigel plugs with VEGF implanted in EGKO mice induced fewer capillaries than those in control mice. The vessels and endothelial cells (ECs) derived from EGKO mice were defective in vascular sprouting and tube formation induced by VEGF. Biochemical analyses revealed a substantial reduction of endothelial NOS (eNOS) activation in Gab1-deficient vessels and ECs following VEGF stimulation. Interestingly, the phosphorylation of Akt, an enzyme known to promote VEGF-induced eNOS activation, was increased in Gab1-deficient vessels and ECs whereas protein kinase A (PKA) activity was significantly decreased. Introduction of an active form of PKA rescued VEGF-induced eNOS activation and tube formation in EGKO ECs. Reexpression of WT or mutant Gab1 molecules in EGKO ECs revealed requirement of Gab1/Shp2 association for the activation of PKA and eNOS. Taken together, these results identify Gab1 as a critical upstream signaling component in VEGF-induced eNOS activation and tube formation, which is dependent on PKA. Of note, this pathway is conserved in primary human ECs for VEGF-induced eNOS activation and tube formation, suggesting considerable potential in treatment of human ischemic diseases.
authors.affiliation: Laboratory of Vascular Biology, Institute of Molecular MedicineChinese and Western Medicine, School of Basic Medical Sciences, Tasly Microcirculation Research Center, Peking University, Beijing 100871, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Lu
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiong
authors.forename: Yingqing
authors.initials: Y
authors.lastname: Huo
authors.forename: Jingyan
authors.initials: J
authors.lastname: Han
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Rongli
authors.initials: R
authors.lastname: Zhang
authors.forename: De-Sheng
authors.initials: DS
authors.lastname: Zhu
authors.forename: Stefan
authors.initials: S
authors.lastname: Klein-Hessling
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Han
authors.forename: Yanli
authors.initials: Y
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Shen
authors.forename: Yulong
authors.initials: Y
authors.lastname: He
authors.forename: Masabumi
authors.initials: M
authors.lastname: Shibuya
authors.forename: Gen-Sheng
authors.initials: GS
authors.lastname: Feng
authors.forename: Jincai
authors.initials: J
authors.lastname: Luo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D003094:Collagen; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004338:Drug Combinations; D042783:Endothelial Cells / Q000378:metabolism; D006614:Hindlimb / Q000098:blood supply* / Q000378:metabolism; D006801:Humans; D007511:Ischemia / Q000150:complications*; D007797:Laminin; D051379:Mice; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011509:Proteoglycans; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004338:Drug Combinations; C490897:Gab1 protein, mouse; D007797:Laminin; D010750:Phosphoproteins; D011509:Proteoglycans; D042461:Vascular Endothelial Growth Factor A; C059485:matrigel; D003094:Collagen; D052250:Nitric Oxide Synthase Type III; D051057:Proto-Oncogene Proteins c-akt; D017868:Cyclic AMP-Dependent Protein Kinases