title: Aquaporin expression in blood-retinal barrier cells during experimental autoimmune uveitis.
abstract: OBJECTIVE
  Blood-retinal barrier (BRB) breakdown and retinal edema are major complications of autoimmune uveitis and could be related to deregulation of aquaporin (AQP) expression. We have therefore evaluated the expression of AQP1 and AQP4 on BRB cells during experimental autoimmune uveitis (EAU) in mice.
  
  
  METHODS
  C57Bl6 mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) peptide 1-16. The disease was graded clinically, and double immunolabeling using glial fibrillary acidic protein (GFAP; a marker of disease activity) and AQP1 or AQP4 antibodies was performed at day 28. AQP1 expression was also investigated in mouse retinal pigment epithelium (RPE) cells (B6-RPE07 cell line) by reverse transcriptase PCR and western blot under basal and tumor necrosis factor alpha (TNF-alpha)-stimulated conditions.
  
  
  RESULTS
  In both normal and EAU retina, AQP1 and AQP4 expression were restricted to the photoreceptor layer and to the Müller cells, respectively. Retinal endothelial cells never expressed AQP1. In vasculitis and intraretinal inflammatory infiltrates, decreased AQP1 expression was observed due to the loss of photoreceptors and the characteristic radial labeling of AQP4 was lost. On the other hand, no AQP4 expression was detected in RPE cells. AQP1 was strongly expressed by choroidal endothelial cells, rendering difficult the evaluation of AQP1 expression by RPE cells in vivo. No major differences were found between EAU and controls at this level. Interestingly, B6-RPE07 cells expressed AQP1 in vitro, and TNF-alpha downregulated AQP1 protein expression in those cells.
  
  
  CONCLUSIONS
  Changes in retinal expression of AQP1 and AQP4 during EAU were primarily due to inflammatory lesions, contrasting with major modulation of AQP expression in BRB detected in other models of BRB breakdown. However, our data showed that TNF-alpha treatment strongly modulates AQP1 expression in B6-RPE07 cells in vitro.
authors.affiliation: Laboratory of Biological Chemistry and Nutrition, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Elie
authors.initials: E
authors.lastname: Motulsky
authors.forename: Philippe
authors.initials: P
authors.lastname: Koch
authors.forename: Sarah
authors.initials: S
authors.lastname: Janssens
authors.forename: Maité
authors.initials: M
authors.lastname: Liénart
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Vanbellinghen
authors.forename: Nargis
authors.initials: N
authors.lastname: Bolaky
authors.forename: Chi-Chao
authors.initials: CC
authors.lastname: Chan
authors.forename: Laure
authors.initials: L
authors.lastname: Caspers
authors.forename: Maria-Dolores
authors.initials: MD
authors.lastname: Martin-Martinez
authors.forename: Heping
authors.initials: H
authors.lastname: Xu
authors.forename: Christine
authors.initials: C
authors.lastname: Delporte
authors.forename: François
authors.initials: F
authors.lastname: Willermain
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000235:genetics / Q000378:metabolism*; D051401:Aquaporin 4 / Q000378:metabolism*; D001813:Blood-Retinal Barrier / Q000378:metabolism* / Q000473:pathology*; D002460:Cell Line; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014605:Uveitis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*
chemical_list: C496021:Aqp1 protein, mouse; C496031:Aqp4 protein, mouse; D051401:Aquaporin 4; D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; D051398:Aquaporin 1
references.citation: Ophthalmic Res. 2004 Sep-Oct;36(5):241-9
references.pmid: 15583429
references.citation: Mol Vis. 2007 Mar 01;13:309-17
references.pmid: 17356517
references.citation: Exp Eye Res. 2003 Apr;76(4):493-504
references.pmid: 12634113
references.citation: Invest Ophthalmol Vis Sci. 2005 Jul;46(7):2487-94
references.pmid: 15980240
references.citation: Prog Retin Eye Res. 2008 Jul;27(4):420-33
references.pmid: 18501660
references.citation: Neuroscience. 2004;129(4):1045-56
references.pmid: 15561419
references.citation: Invest Ophthalmol Vis Sci. 2005 Oct;46(10):3869-75
references.pmid: 16186376
references.citation: Invest Ophthalmol Vis Sci. 2008 Aug;49(8):3699-706
references.pmid: 18421091
references.citation: Invest Ophthalmol Vis Sci. 2004 Dec;45(12):4477-83
references.pmid: 15557457
references.citation: Neurosci Lett. 2007 Jun 27;421(2):132-6
references.pmid: 17566653
references.citation: Int Ophthalmol Clin. 2005 Spring;45(2):1-13
references.pmid: 15791154
references.citation: J Neurosci. 1998 Apr 1;18(7):2506-19
references.pmid: 9502811
references.citation: Invest Ophthalmol Vis Sci. 2003 Jun;44(6):2803-8
references.pmid: 12766090
references.citation: Prog Brain Res. 2007;161:185-94
references.pmid: 17618977
references.citation: Invest Ophthalmol Vis Sci. 2006 Dec;47(12):5545-52
references.pmid: 17122147
references.citation: Acta Ophthalmol Scand. 2005 Oct;83(5):528-38
references.pmid: 16187988
references.citation: Invest Ophthalmol Vis Sci. 2008 Jan;49(1):282-9
references.pmid: 18172104
references.citation: J Biol Chem. 2005 Apr 8;280(14):13906-12
references.pmid: 15695511
references.citation: Neurosci Lett. 2005 Nov 11;388(2):96-9
references.pmid: 16039047
references.citation: J Neuroimmunol. 2005 Apr;161(1-2):145-54
references.pmid: 15748953
references.citation: Am J Physiol. 1998 May;274(5):C1332-45
references.pmid: 9612221
references.citation: Angew Chem Int Ed Engl. 2004 Aug 20;43(33):4278-90
references.pmid: 15368374
references.citation: Ophthalmology. 2006 Aug;113(8):1446-9
references.pmid: 16877081
references.citation: Prog Retin Eye Res. 2001 Nov;20(6):761-97
references.pmid: 11587917
references.citation: Exp Eye Res. 2008 Oct;87(4):319-26
references.pmid: 18634784
references.citation: Physiol Rev. 2005 Jul;85(3):845-81
references.pmid: 15987797