Angiopoietin-related growth factor enhances blood flow via activation of the ERK1/2-eNOS-NO pathway in a mouse hind-limb ischemia model.
OBJECTIVE
Transgenic mice overexpressing angiopoietin-related growth factor (AGF) exhibit enhanced angiogenesis, suggesting that AGF may be a useful drug target in ischemic disease. Our goal was to determine whether AGF enhances blood flow in a mouse hind-limb ischemia model and to define molecular mechanisms underlying AGF signaling in endothelial cells.


RESULTS
Intramuscular injection of adenovirus harboring AGF into the ischemic limb increased AGF production, which increased blood flow through induction of angiogenesis and arteriogenesis, thereby reducing the necessity for limb amputation. In vitro analysis showed that exposing human umbilical venous endothelial cells to AGF increased nitric oxide (NO) production through activation of an ERK1/2-endothelial NO synthetase (eNOS) signaling pathway. AGF-stimulated eNOS phosphorylation, NO production, and endothelial cell migration were all abolished by specific MEK1/2 inhibitors. Moreover, AGF did not restore blood flow to ischemic hind-limbs of either mice receiving NOS inhibitor L-NAME or eNOS knockout mice.


CONCLUSIONS
Activation of an ERK1/2-eNOS-NO pathway is a crucial signaling mechanism by which AGF increases blood flow through induction of angiogenesis and arteriogenesis. Further investigation of the regulation underlying AGF signaling pathway may contribute to develop a new clinical strategy for ischemic vascular diseases.
Urano
Takashi
T
Laboratory of Vascular Biology and Metabolism, Center for Integrated Medical Research, Department of Cell Differentiation, School of Medicine, Keio University, Tokyo, Japan.
Ito
Yasuhiro
Y
Akao
Masaki
M
Sawa
Tomohiro
T
Miyata
Keishi
K
Tabata
Mitsuhisa
M
Morisada
Tohru
T
Hato
Tai
T
Yano
Masato
M
Kadomatsu
Tsuyoshi
T
Yasunaga
Kunio
K
Shibata
Rei
R
Murohara
Toyoaki
T
Akaike
Takaaki
T
Tanihara
Hidenobu
H
Suda
Toshio
T
Oike
Yuichi
Y
D000091308:Angiopoietin-Like Protein 6; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; D000818:Animals; D001685:Biological Factors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004789:Enzyme Activation; D006614:Hindlimb / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D014471:Umbilical Veins / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D000091308:Angiopoietin-Like Protein 6; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; C477602:Angptl6 protein, mouse; D001685:Biological Factors; D012333:RNA, Messenger; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3