Rat glomerular epithelial cells in culture express characteristics of parietal, not visceral, epithelium

Talia Weinstein, Richard Cameron, Allan Katz, Mel Silverman

Research output: Contribution to journalArticlepeer-review

Abstract

Glomerular epithelial cells (GEC) in culture are derived from intact isolated glomeruli. Although there is general agreement about distinguishing GEC from mesangial and endothelial cells, there is still uncertainty regarding the visceral versus parietal origin of cultured GEC. If these cells are to provide a useful model system, it is necessary to establish well-defined cell populations. The purpose of this study was to evaluate this important issue by comparing the characteristics of cultured GEC with glomerular epithelium from rat kidney sections. By electron microscopy, GEC were polygonal, with cilia and desmosomes between cells, similar to parietal cells in situ. Because intermediate filaments are specifically expressed in differentiated cells in the kidney, the expression of intermediate filaments in cultured GEC were compared with those of intact glomeruli. Cultured GEC are positive for cytokeratin and negative for vimentin and desmin, identical to parietal cells in situ. In contrast, podocytes are positive for vimentin and desmin and negative for cytokeratin. In vivo, podocytes express gp330 and puromycin-aminonucleoside (PAN) susceptibility, which are used as markers for cultured GEC. Immunoperoxidase staining of rat kidney sections with monoclonal anti-gp330 demonstrated gp330 localization to the cell surface and coated pits of the parietal cells, similar to its localization in podocytes. The presence of gp330 in cultured GEC was confirmed by immunoblot. PAN administration to rats induced vacuolization and detachment from the basement membrane in the parietal cells of Bowman's capsule, similar to the cytotoxicity observed in podocytes. In summary, cultured rat GEC express phenotypic characteristics of parietal and not visceral epithelium. PAN sensitivity and the expression of gp330 are shared by both glomerular epithelia in vivo, and therefore, they cannot serve as specific markers in vitro.

Original languageEnglish
Pages (from-to)1279-1287
Number of pages9
JournalJournal of the American Society of Nephrology : JASN
Volume3
Issue number6
StatePublished - Dec 1992
Externally publishedYes

Keywords

  • Glomerular epithelial cell culture

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