title: The role of cytochrome P450 epoxygenases in retinal angiogenesis.
abstract: OBJECTIVE
  The purpose of this study was to investigate the role(s) of cytochrome P450 epoxygenases (CYPs) and their products, the epoxyeicosatrienoic acids (EETs), in hypoxia-induced VEGF production and pathologic retinal angiogenesis.
  
  
  METHODS
  Human retinal astrocytes, Müller cells, and retinal microvascular endothelial cells (HRMEC) were exposed to hypoxia, and relative CYP2C expression was measured by RT-PCR. Astrocyte and Müller cell VEGF production was measured by ELISA after exposure to hypoxia and treatment with the general CYP inhibitor, SKF-525a. Human retinal microvascular endothelial cells were treated with the CYP product, 11,12-epoxyeicosatrienoic acid [EET], or SKF-525a in the presence or absence of VEGF. Proliferation of HRMEC and tube formation were assayed. Oxygen-induced retinopathy (OIR) was induced in newborn rats. Retinal CYP2C11 and CYP2C23 expression were measured by RT-PCR. The OIR rats received SKF-525a by intravitreal injection and preretinal neovascularization (NV) was quantified. Retinal VEGF protein levels were measured by ELISA.
  
  
  RESULTS
  Human retinal astrocytes were the only cells to exhibit significant induction of CYP2C8 and CYP2C9 mRNA expression by hypoxia. Astrocytes, but not Müller cells, exhibited reduced hypoxia-induced VEGF production when treated with SKF-525a. 11,12-EET induced HRMEC proliferation and tube formation, and SKF-525a inhibited VEGF-induced proliferation. Oxygen-induced retinopathy induced expression of CYP2C23, but had no effect on CYP2C11. SKF-525a inhibited retinal NV and reduced retinal VEGF levels in OIR rats.
  
  
  CONCLUSIONS
  The CYP-derived 11,12-EET may exhibit a proangiogenic biological function in the retina following stimulation by hypoxia in astrocytes. Inhibition of CYP may provide a rational therapy against retinal NV, because it can reduce VEGF production and VEGF-induced angiogenic responses in endothelial cells.
authors.affiliation: Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Capozzi
authors.affiliation: Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, United States.
authors.forename: Gary W
authors.initials: GW
authors.lastname: McCollum
authors.affiliation: Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, United States.
authors.forename: John S
authors.initials: JS
authors.lastname: Penn
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis / Q000235:genetics; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D002478:Cells, Cultured; D065727:Cytochrome P-450 CYP2C8; D065729:Cytochrome P-450 CYP2C9; D000090762:Cytochrome P-450 CYP2J2; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000235:genetics*; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008833:Microcirculation; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D012160:Retina / Q000378:metabolism / Q000473:pathology*; D015861:Retinal Neovascularization / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: C000717351:Cyp2c23 protein, rat; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C400322:cytochrome P-450 CYP2C subfamily; D003577:Cytochrome P-450 Enzyme System; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; C450259:CYP2C8 protein, human; D065727:Cytochrome P-450 CYP2C8; D000090762:Cytochrome P-450 CYP2J2
keywords: angiogenesis; cytochrome P450; epoxyeicosatrienoic acid; retinopathy of prematurity