title: Novel expression of claudin-5 in glomerular podocytes.
abstract: Tight junctions are the main intercellular junctions of podocytes of the renal glomerulus under nephrotic conditions. Their requisite components, claudins, still remain to be identified. We have measured the mRNA levels of claudin subtypes by quantitative real-time PCR using isolated rat glomeruli. Claudin-5 was found to be expressed most abundantly in glomeruli. Mass spectrometric analysis of membrane preparation from isolated glomeruli also confirmed only claudin-5 expression without any detection of other claudin subtypes. In situ hybridization and immunolocalization studies revealed that claudin-5 was localized mainly in glomeruli where podocytes were the only cells expressing claudin-5. Claudin-5 protein was observed on the entire surface of podocytes including apical and basal domains of the plasma membrane in the normal condition and was inclined to be concentrated on tight junctions in puromycin aminonucleoside nephrosis. Total protein levels of claudin-5 in isolated glomeruli were not significantly upregulated in the nephrosis. These findings suggest that claudin-5 is a main claudin expressed in podocytes and that the formation of tight junctions in the nephrosis may be due to local recruitment of claudin-5 rather than due to total upregulation of the claudin protein levels.
authors.affiliation: Department of Structural Pathology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata 951-8510, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Koda
authors.forename: Linning
authors.initials: L
authors.lastname: Zhao
authors.forename: Eishin
authors.initials: E
authors.lastname: Yaoita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Sachiko
authors.initials: S
authors.lastname: Tsukita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nameta
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Fujinaka
authors.forename: Sameh
authors.initials: S
authors.lastname: Magdeldin
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.forename: Ichiei
authors.initials: I
authors.lastname: Narita
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D062507:Claudin-5; D057167:Claudins / Q000235:genetics / Q000378:metabolism*; D007678:Kidney Glomerulus / Q000166:cytology* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D050199:Podocytes / Q000378:metabolism* / Q000648:ultrastructure; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D011692:Puromycin Aminonucleoside / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY
chemical_list: D062507:Claudin-5; D057167:Claudins; C491510:Cldn5 protein, rat; D008565:Membrane Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011692:Puromycin Aminonucleoside