title: (Pro)renin receptor is associated with angiogenic activity in proliferative diabetic retinopathy.
abstract: OBJECTIVE
  The renin-angiotensin system (RAS) potentially has a role in the development of end-organ damage, and tissue RAS activation has been suggested as a risk factor for diabetic retinopathy. We have recently shown significant involvement of (pro)renin receptor ([P]RR) in retinal inflammation in a rodent model of early diabetes. In this study we aim to elucidate the (P)RR-associated pathogenesis of fibrovascular proliferation, a late-stage angiogenic complication in human diabetic retinopathy.
  
  
  METHODS
  Vitreous fluids from 23 eyes of patients with proliferative diabetic retinopathy (PDR) and 16 eyes of controls with non-diabetic, idiopathic macular diseases (macular hole and epiretinal membrane) were collected. Protein levels of soluble (P)RR were measured by ELISA, and immunofluorescence was performed to assess the localisation of (P)RR and related molecules in fibrovascular tissues from PDR eyes.
  
  
  RESULTS
  (P)RR immunoreactivity was detected in neovascular endothelial cells, colocalised with prorenin, phosphorylated extracellular signal-regulated kinase (ERK) and vascular endothelial growth factor (VEGF). Prorenin application to human retinal microvascular endothelial cells significantly upregulated mRNA expression of VEGF, especially the VEGF165 isoform, which was abolished by (P)RR or ERK signalling blockade. Proteases known to cleave (P)RR, including furin, were positive in endothelial cells in fibrovascular tissues. Protein levels of soluble (P)RR in vitreous fluids were higher in PDR eyes than in non-diabetic control eyes, and correlated significantly with vitreous prorenin and VEGF levels and the vascular density of fibrovascular tissues.
  
  
  CONCLUSIONS
  Our data using human samples provide the first evidence that (P)RR is associated with angiogenic activity in PDR.
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kanda
authors.forename: K
authors.initials: K
authors.lastname: Noda
authors.forename: W
authors.initials: W
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Ishida
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D051379:Mice; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000473:pathology; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000502:physiology*; D012163:Retinal Detachment / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D012171:Retinal Vessels / Q000378:metabolism / Q000473:pathology; D015854:Up-Regulation / Q000502:physiology; D025262:Vacuolar Proton-Translocating ATPases / Q000276:immunology / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism / Q000473:pathology; D000093342:Prorenin Receptor
chemical_list: C458319:ATP6AP2 protein, human; D000911:Antibodies, Monoclonal; D011956:Receptors, Cell Surface; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D025262:Vacuolar Proton-Translocating ATPases; D000093342:Prorenin Receptor