title: Mitochondrial reactive oxygen species and c-Src play a critical role in hypoxic response in vascular smooth muscle cells.
abstract: OBJECTIVE
  Thickened atherosclerotic plaques are prone to be hypoxic because of poor perfusion. In this study, we tested (a) whether reactive oxygen species (ROS) and c-Src play roles in hypoxic induction of HIF-1alpha protein and PAI-1 gene expression in the rabbit aortic smooth muscle cell line C2/2 cells and primary cultures of rat aortic smooth muscle cells, and (b) how mitochondria act on the hypoxia-induced signaling mechanism.
  
  
  RESULTS
  Hypoxic exposure of C2/2 cells increased H2O2 generation, c-Src phosphorylation, HIF-1alpha protein expression, and PAI-1 gene expression. Catalase, a scavenger of H2O2, inhibited the hypoxia-induced ROS generation and PAI-1 gene expression. Src kinase inhibitors PP1 and PP2 inhibited hypoxia-induced HIF-1alpha protein and PAI-1 gene expression. Ablation of mitochondrial respiration by rotenone abolished hypoxia-induced ROS generation, c-Src phosphorylation, HIF-1alpha protein expression, and PAI-1 gene expression.
  
  
  CONCLUSIONS
  Induction of HIF-1alpha protein and PAI-1 gene expression in response to hypoxia was regulated by ROS production and c-Src activation in vascular smooth muscle cells. Mitochondria linked the hypoxic signal to c-Src, which in turn led to HIF-1alpha protein and PAI-1 gene expression. These results provide evidence that hypoxia induces the ROS-mediated and c-Src-dependent signaling cascades which are closely associated with angiogenesis and thrombosis in atherosclerotic vasculature.
authors.affiliation: Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Sato
authors.forename: Mahito
authors.initials: M
authors.lastname: Sato
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Kanai
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Uchiyama
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Iso
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ohyama
authors.forename: Hironosuke
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Junichi
authors.initials: J
authors.lastname: Tamura
authors.forename: Ryozo
authors.initials: R
authors.lastname: Nagai
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kurabayashi
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D002374:Catalase / Q000494:pharmacology; D015687:Cell Hypoxia; D002460:Cell Line; D005419:Flavonoids / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D012402:Rotenone / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: C108123:4-amino-5-(4-methylphenyl)-7-(tert-butyl)pyrazolo(3,4-d)pyrimidine; C412373:AG 1879; D000730:Androstadienes; D005419:Flavonoids; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007093:Imidazoles; D009281:Naphthalenes; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017395:Plasminogen Activator Inhibitor 1; D047428:Protein Kinase Inhibitors; D011720:Pyrazoles; D011725:Pyridines; D011743:Pyrimidines; D012333:RNA, Messenger; C061465:calphostin complex; D012402:Rotenone; D006861:Hydrogen Peroxide; D002374:Catalase; D016392:Proto-Oncogene Proteins pp60(c-src); C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin