title: AMP-activated protein kinase signaling stimulates VEGF expression and angiogenesis in skeletal muscle.
abstract: AMP-activated protein kinase (AMPK) is regulated by various cellular stresses. Vascular endothelial growth factor (VEGF), a key regulator of angiogenesis, is also upregulated by several stress-inducible factors such as hypoxia and stimulation by cytokines and growth factors. Here, we investigated whether AMPK signaling in muscle has a role in regulating VEGF-mediated angiogenic processes. AICAR stimulated VEGF mRNA and protein levels in C2C12 myotube cultures. Transduction with dominant-negative AMPK abolished AICAR-induced VEGF expression at both steady state mRNA and protein levels. AICAR increased VEGF mRNA stability without affecting VEGF promoter activity. AICAR also stimulated p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation. Activation of p38 MAPK was suppressed by transduction with dominant-negative AMPK, suggesting that AMPK is upstream of p38 MAPK. The p38 MAPK inhibitor SB203580 blocked AICAR-induced increase in VEGF mRNA and protein levels, indicating that AICAR-mediated VEGF induction is dependent on p38 MAPK signaling. AICAR treatment increased VEGF expression and accelerated angiogenic repair of ischemic hindlimbs in mice in an AMPK-dependent manner. These data indicate that AMPK-p38 MAPK signaling cascade can increase VEGF production in muscle and promote angiogenesis in response to ischemic injury.
authors.affiliation: Molecular Cardiology/Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Mass 02118, USA.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ouchi
authors.forename: Rei
authors.initials: R
authors.lastname: Shibata
authors.forename: Kenneth
authors.initials: K
authors.lastname: Walsh
mesh_terms: D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D007093:Imidazoles / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D051379:Mice; D009097:Multienzyme Complexes / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply*; D018919:Neovascularization, Physiologic; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D012265:Ribonucleotides / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
chemical_list: D007093:Imidazoles; D009097:Multienzyme Complexes; D011725:Pyridines; D012333:RNA, Messenger; D012265:Ribonucleotides; D042461:Vascular Endothelial Growth Factor A; D000620:Aminoimidazole Carboxamide; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; C093642:SB 203580