Altered tight junctions and fence function in NRK-52E cells induced by aristolochic acid

Hum Exp Toxicol. 2012 Jan;31(1):32-41. doi: 10.1177/0960327111407645. Epub 2011 May 10.

Abstract

Aristolochic acid (AA) can accumulate in the tubulointerstitium and cause kidney-specific injuries. However, the mechanism by which AA induces nephropathy remains largely unknown. This study explored the effect of AA-I on tight junctions (TJs), and the fence function in a renal epithelial cell (REC). NRK-52E cells were exposed to different concentrations of AA-I for 4 h or 25 μM AA-I for different time. Cell viability was detected by MTT, cell apoptosis by flow cytometric analysis, the expression of zonula occludens-1 (ZO-1), E-cadherin and polarity scaffold (Par3) by western blot and immunofluorescence, cell membrane permeability by transepithelial electrical resistance (TEER). It was found that AA-I reduced the expression of ZO-1, E-cadherin, and Par3 in a concentration- and time-dependent fashion, and altered the distribution of ZO-1 and Par3 from cell membrane to cell plasma. In parallel to the reduced expression of TJ proteins, TEER exhibited a significant reduction in response to AA-I treatment in a time- and concentration-dependent manner. Meanwhile, α-SMA expression in cells was increased following AA-I treatment. In contrast, cell viability and apoptosis were unaltered with the doses of AA-I tested. Our findings show for the first time that AA-I treatment in cultured RECs induced a rapid disruption of TJ and the fence function preceding apoptosis, which indicated that aberrant expression of TJ proteins within RECs may be involved in initiating the renal tubulointerstitial disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Aristolochic Acids / toxicity*
  • Cadherins / metabolism
  • Carrier Proteins
  • Cell Line
  • Cell Survival / drug effects
  • Kidney / cytology
  • Kidney / metabolism*
  • Membrane Proteins / metabolism
  • Nerve Tissue Proteins
  • Phosphoproteins / metabolism
  • Rats
  • Tight Junctions / drug effects*
  • Tight Junctions / metabolism
  • Zonula Occludens-1 Protein

Substances

  • Aristolochic Acids
  • Cadherins
  • Carrier Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Pard3 protein, rat
  • Phosphoproteins
  • Tjp1 protein, rat
  • Zonula Occludens-1 Protein
  • aristolochic acid I