Transdifferentiation of cultured tubular cells induced by hypoxia

Krissanapong Manotham, Tetsuhiro Tanaka, Makiko Matsumoto, Takamoto Ohse, Reiko Inagi, Toshio Miyata, Kiyoshi Kurokawa, Toshiro Fujita, Julie R. Ingelfinger, Masaomi Nangaku

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157 Citations (Scopus)

Abstract

Background. Tubulointerstitial fibrosis leads to progressive kidney disease and, ultimately, may result in end-stage renal disease (ESRD). Myofibroblasts, which express α-smooth muscle actin (a-SMA) in their cytoplasm, regulate renal fibrogenesis. Recent studies suggest that certain interstitial myofibroblasts derive from renal tubular cells that have undergone epithelial-mesenchymal transformation (EMT) (transdifferentiation). However, the role(s) of hypoxia, which is involved in progressive kidney disease, on tubular EMT remains unclear. Methods. Immortalized rat proximal tubular cells (IRPTC) were cultured in normobaric hypoxia (1% O2) for 3, 6, or 15 days, with match control in normoxic conditions, α-SMA, vimentin, and desmin chosen as markers of EMT were measured by immunocytochemistry and immunoblots collagen I production and cell motility were chosen as functional assays. Various concentrations of cobaltous chloride (CoCl2) were used as hypoxic mimickers. In vivo studies were carried out in a chronic ischemic kidney model. Results. Immunohistochemical studies revealed increased expression of α-SMA. Striking morphologic changes were detected after 6 days of hypoxia for α-SMA-positive fibroblast-like cells (SMA + fib) and after 15 days for α-SMA-positive myofibroblast-like cells (SMA + myo). Immunoblots confirmed these findings. Collagen I production increased in a time-dependent manner parallel to α-SMA expression. Cell motility assays demonstrated that transformed cells had higher migratory capacity than normal tubular cells. Cobaltous salt also induced α-SMA and collagen I synthesis. Chronic ischemic kidney revealed in vivo tubular EMT at day 7. Conclusion. Hypoxia can induce tubular EMT. This process may play an important role in progression of kidney disease.

Original languageEnglish
Pages (from-to)871-880
Number of pages10
JournalKidney international
Volume65
Issue number3
DOIs
Publication statusPublished - 2004 Mar
Externally publishedYes

Keywords

  • Epithelial mesenchymal transformation
  • Hypoxia
  • Myofibroblast
  • Smooth muscle actin
  • Transdifferentiation
  • Tubuloitnterstitial fibrosis

ASJC Scopus subject areas

  • Nephrology

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  • Cite this

    Manotham, K., Tanaka, T., Matsumoto, M., Ohse, T., Inagi, R., Miyata, T., Kurokawa, K., Fujita, T., Ingelfinger, J. R., & Nangaku, M. (2004). Transdifferentiation of cultured tubular cells induced by hypoxia. Kidney international, 65(3), 871-880. https://doi.org/10.1111/j.1523-1755.2004.00461.x