title: Aquaporin expression and function in human pluripotent stem cell-derived retinal pigmented epithelial cells.
abstract: OBJECTIVE
  Aquaporins (AQPs), a family of transmembrane water channel proteins, are essential for allowing passive water transport through retinal pigmented epithelial (RPE) cells. Even though human native RPE cells and immortalized human RPEs have been shown to express AQPs, the expression of AQPs during the differentiation in stem cell-derived RPE remains to be elucidated.
  
  
  METHODS
  In human embryonic (hESCs) and induced pluripotent stem cells (hiPSCs)-derived RPE cells, the expression of several AQPs was determined by quantitative real-time PCR and the localization of AQP1 was assessed with confocal microscopy. The functionality of AQP water channels was determined by cell volume assay in hESC-derived RPE cells.
  
  
  RESULTS
  AQP1, AQP3, AQP4, AQP5, AQP6, AQP7, AQP10, AQP11, and AQP12 were expressed in hESC- and hiPSC-derived RPE cells. Furthermore, the expression of AQP1 and AQP11 genes were significantly upregulated during the maturation of both hESC and iPSC into RPE. Confocal microscopy shows the expression of AQP1 at the apical plasma membrane of polarized cobblestone hESC- and hiPSC-derived RPE cells. Lastly, aquaporin inhibitors significantly reduced AQP functionality in hESC-RPE cells.
  
  
  CONCLUSIONS
  hESC-RPE and hiPSC-RPE cells express several AQP genes, which are functional in mature hESC-derived RPE cells. The localization of AQP1 on the apical plasma membrane in mature RPE cells derived from both hESC and hiPSC suggests its functionality. These data propose that hESC- and hiPSC-derived RPE cells, grown and differentiated under serum-free conditions, resemble their native counterpart in the human eye.
authors.affiliation: Institute of Biomedical Technology, University of Tampere, BioMediTech, Tampere, Finland. kati.juuti-uusitalo@uta.fi
authors.forename: Kati
authors.initials: K
authors.lastname: Juuti-Uusitalo
authors.forename: Christine
authors.initials: C
authors.lastname: Delporte
authors.forename: Francoise
authors.initials: F
authors.lastname: Grégoire
authors.forename: Jason
authors.initials: J
authors.lastname: Perret
authors.forename: Heini
authors.initials: H
authors.lastname: Huhtala
authors.forename: Virpi
authors.initials: V
authors.lastname: Savolainen
authors.forename: Soile
authors.initials: S
authors.lastname: Nymark
authors.forename: Jari
authors.initials: J
authors.lastname: Hyttinen
authors.forename: Hannu
authors.initials: H
authors.lastname: Uusitalo
authors.forename: Francois
authors.initials: F
authors.lastname: Willermain
authors.forename: Heli
authors.initials: H
authors.lastname: Skottman
mesh_terms: D051398:Aquaporin 1 / Q000235:genetics / Q000378:metabolism; D020346:Aquaporins / Q000235:genetics* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D017097:Electric Impedance; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation / Q000502:physiology*; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism; D051739:Microphthalmia-Associated Transcription Factor / Q000378:metabolism; D018613:Microscopy, Confocal; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D020346:Aquaporins; D015415:Biomarkers; D005136:Eye Proteins; D018398:Homeodomain Proteins; C497234:MITF protein, human; D051739:Microphthalmia-Associated Transcription Factor; D000071841:PAX6 Transcription Factor; C000605730:PAX6 protein, human; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger; D012097:Repressor Proteins; D051398:Aquaporin 1; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating)
keywords: aquaporins; retinal pigment epithelium; stem cells