title: The mRNA of claudins is expressed in the endolymphatic sac epithelia.
abstract: OBJECTIVE
  Claudins are a family of membrane proteins which localize to tight junctions (TJs). Recent studies have shown that claudins can form pores for ions in the TJs and regulate the permeability of epithelial paracellular ion transport. The endolymphatic sac (ES) is a part of the inner ear, absorbing the endolymphatic fluid. ES dysfunction may result in endolymphatic hydrops. In this study, we focused on the paracellular transport and examined claudin mRNA expression in the ES epithelia.
  
  
  METHODS
  Total RNA was isolated from whole ES epithelia of rats by laser capture microdissection. RT-PCR was used to evaluate the expression of claudins. The expression of each claudin mRNA in the epithelial cells of rat ES was confirmed by in situ hybridization.
  
  
  RESULTS
  RT-PCR indicated the expression of cldn2, cldn4, cldn6, cldn7, cldn9, cldn11, cldn12, and cldn14. The expression of these claudin mRNAs in the epithelial cells of rat ES was confirmed by in situ hybridization.
  
  
  CONCLUSIONS
  We demonstrated mRNA expression of multiple claudins in the rat ES epithelia. These results in the ES epithelia were consistent with a role of claudins in paracellular ion transport.
authors.affiliation: Department of Otolaryngology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan. aimatsu@med.kagawa-u.ac.jp
authors.forename: Ai
authors.initials: A
authors.lastname: Matsubara
authors.forename: Takenori
authors.initials: T
authors.lastname: Miyashita
authors.forename: Terushige
authors.initials: T
authors.lastname: Mori
authors.forename: Kosuke
authors.initials: K
authors.lastname: Akiyama
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Inamoto
authors.forename: Nozomu
authors.initials: N
authors.lastname: Mori
mesh_terms: D000818:Animals; D057167:Claudins / Q000235:genetics / Q000378:metabolism*; D004712:Endolymphatic Sac / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D017403:In Situ Hybridization; D017136:Ion Transport / Q000502:physiology; D061346:Laser Capture Microdissection; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019108:Tight Junctions / Q000502:physiology
chemical_list: D057167:Claudins; D012333:RNA, Messenger