title: Aquaporins 6-12 in the human eye.
abstract: OBJECTIVE
  Aquaporins (AQPs) are widely expressed and have diverse distribution patterns in the eye. AQPs 0-5 have been localized at the cellular level in human eyes. We investigated the presence of the more recently discovered AQPs 6-12 in the human eye.
  
  
  METHODS
  RT-PCR was performed on fresh tissue from two human eyes divided into the cornea, corneal limbus, ciliary body and iris, lens, choroid, optic nerve, retina and sclera. Each structure was examined to detect the mRNA of AQPs 6-12. Twenty-one human eyes were examined using immunohistochemical and immunofluorescence techniques to determine the topographical localization of AQPs 6-12.
  
  
  RESULTS
  mRNA transcripts of AQP7, AQP9 and AQP11 were found in the ciliary body, corneo-limbal tissue, optic nerve, retina and sclera. AQP9 and AQP11 mRNA was also detected in the choroid. No mRNA of AQP6, AQP8, AQP10 or AQP12 was detected. Anti-AQP7 immunolabelling was detected in the corneal epithelium, corneal endothelium, trabecular meshwork endothelium, ciliary epithelia, lens epithelium, the inner and outer limiting membrane of the retina, the retinal pigment epithelium and the capillary endothelium of all parts of the eye. AQP9 immunolabelling was detected in the nonpigmented ciliary epithelium and retinal ganglion cells. AQP11 immunolabelling was detected in the corneo-limbal epithelium, nonpigmented ciliary epithelium and inner limiting membrane of the retina.
  
  
  CONCLUSIONS
  Selective expression of AQP7, AQP9 and AQP11 was found within various structures of the human eye. The detection of these aquaporins in the eye implies a role that may be related not only to water transport but also to the transport of glycerol, lactate and ammonia, with importance for metabolism, especially in the retina.
authors.affiliation: Eye Pathology Institute, Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
authors.forename: Thuy Linh
authors.initials: TL
authors.lastname: Tran
authors.forename: Toke
authors.initials: T
authors.lastname: Bek
authors.forename: Lars
authors.initials: L
authors.lastname: Holm
authors.forename: Morten
authors.initials: M
authors.lastname: la Cour
authors.forename: Søren
authors.initials: S
authors.lastname: Nielsen
authors.forename: Jan Ulrik
authors.initials: JU
authors.lastname: Prause
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Rojek
authors.forename: Steffen
authors.initials: S
authors.lastname: Hamann
authors.forename: Steffen
authors.initials: S
authors.lastname: Heegaard
mesh_terms: D051403:Aquaporin 6 / Q000235:genetics / Q000378:metabolism; D020346:Aquaporins / Q000235:genetics* / Q000378:metabolism; D005123:Eye / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D007124:Immunoenzyme Techniques; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution
chemical_list: C438667:AQP10 protein, human; C511251:AQP11 protein, human; C501067:AQP12A protein, human; C114141:AQP7 protein, human; C109669:AQP9 protein, human; D051403:Aquaporin 6; D020346:Aquaporins; D012333:RNA, Messenger; C108330:aquaporin 8