title: Role of nonproteolytically activated prorenin in pathologic, but not physiologic, retinal neovascularization.
abstract: OBJECTIVE
  Recently, it was revealed that the inhibition of nonproteolytic activation of prorenin led to significant suppression of ocular inflammation in endotoxin-induced uveitis. The purpose of the present study was to investigate whether nonproteolytically activated prorenin plays a role in ischemia-induced retinal neovascularization.
  
  
  METHODS
  C57BL/6 neonatal mice were reared in an 80% concentration of oxygen from postnatal (P) day 7 to P12, followed by room-air breathing to P17 to induce ischemia-initiated retinal neovascularization. Tissue localization of activated prorenin and prorenin receptor was examined by immunohistochemistry. Animals received intraperitoneal injections of handle-region peptide (HRP), a decoy peptide corresponding to the handle region of prorenin, which inhibits prorenin receptor-mediated upregulation of the renin-angiotensin system (RAS). A concanavalin A lectin perfusion-labeling technique was used to evaluate the areas of physiologic and pathologic retinal new vessels and the number of leukocytes adhering to the vasculature. Retinal mRNA expression and protein levels of intercellular adhesion molecule (ICAM)-1, vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)-1, and VEGFR-2 were examined by RT-PCR and ELISA.
  
  
  RESULTS
  Retinal vessels in ischemic retinopathy eyes were positive for activated prorenin and prorenin receptor. Pathologic, but not physiologic, retinal neovascularization was significantly attenuated in HRP-treated mice compared with vehicle- or control peptide-treated animals. The number of adherent leukocytes was also significantly reduced. Retinal mRNA expression and protein levels of ICAM-1, VEGF, VEGFR-1, and VEGFR-2 in ischemic retinopathy were also significantly suppressed by the application of HRP.
  
  
  CONCLUSIONS
  The present findings suggest that nonproteolytic activation of prorenin selectively promotes pathologic, but not physiologic, retinal neovascularization through the inflammatory processes related to pathologic neovascularization.
authors.affiliation: Laboratory of Retinal Cell Biology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Satofuka
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Ichihara
authors.forename: Norihiro
authors.initials: N
authors.lastname: Nagai
authors.forename: Takashi
authors.initials: T
authors.lastname: Koto
authors.forename: Hajime
authors.initials: H
authors.lastname: Shinoda
authors.forename: Kousuke
authors.initials: K
authors.lastname: Noda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ozawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsubota
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Itoh
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Oike
authors.forename: Susumu
authors.initials: S
authors.lastname: Ishida
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D007124:Immunoenzyme Techniques; D007274:Injections, Intraperitoneal; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D007511:Ischemia / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic; D010446:Peptide Fragments / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D011956:Receptors, Cell Surface / Q000378:metabolism; D012083:Renin / Q000737:chemistry / Q000502:physiology*; D015861:Retinal Neovascularization / Q000209:etiology* / Q000378:metabolism / Q000517:prevention & control; D012171:Retinal Vessels / Q000378:metabolism; D012173:Retinitis / Q000209:etiology* / Q000378:metabolism / Q000517:prevention & control; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000235:genetics / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism; D000093342:Prorenin Receptor; D000092502:Renin Inhibitors
chemical_list: D018799:Intercellular Adhesion Molecule-1; D010446:Peptide Fragments; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D012083:Renin; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D000093342:Prorenin Receptor; D000092502:Renin Inhibitors; C090509:Icam1 protein, mouse; C467480:vascular endothelial growth factor A, mouse; C467498:vascular endothelial growth factor A, rat