Loss of α(E)-catenin promotes Fas mediated apoptosis in tubular epithelial cells

Apoptosis. 2015 Jul;20(7):921-9. doi: 10.1007/s10495-015-1129-x.

Abstract

The aging kidney undergoes structural and functional alterations which make it more susceptible to drug-induced acute kidney injury (AKI). Previous studies in our lab have shown that the expression of α(E)-catenin is decreased in aged kidney and loss of α(E)-catenin potentiates AKI-induced apoptosis, but not necrosis, in renal tubular epithelial cells (NRK-52E cells). However, the specific apoptotic pathway underlying the increased AKI-induced cell death is not yet understood. In this study, cells were challenged with nephrotoxicant cisplatin to induce AKI. A ~5.5-fold increase in Fas expression in C2 (stable α(E)-catenin knockdown) relative to NT3 (non-targeted control) cells was seen. Increased caspase-8 and -9 activation was induced by cisplatin in C2 as compared to NT3 cells. In addition, decreased Bcl-2 expression and increased BID cleavage and cytochrome C release were detected in C2 cells after cisplatin challenge. Treating the cells with cisplatin, in combination with a Bcl-2 inhibitor, decreased the viability of NT3 cells to the same level as C2 cells after cisplatin. Furthermore, caspase-3/-7 activation is blocked by Fas, caspase-8, caspase-9 and pan-caspase inhibitors. These inhibitors also completely abolished the difference in viability between NT3 and C2 cells in response to cisplatin. These results demonstrate a Fas-mediated apoptotic signaling pathway that is enhanced by the age-dependent loss of α(E)-catenin in renal tubule epithelial cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acute Kidney Injury / pathology
  • Animals
  • Antineoplastic Agents / pharmacology
  • Apoptosis Regulatory Proteins / agonists
  • Apoptosis Regulatory Proteins / metabolism
  • Apoptosis*
  • Cell Line
  • Cisplatin / pharmacology
  • Epithelial Cells / metabolism*
  • Gene Knockdown Techniques
  • Kidney Tubules / drug effects
  • Kidney Tubules / metabolism
  • Rats, Inbred F344
  • Signal Transduction
  • alpha Catenin / genetics*
  • fas Receptor / metabolism*

Substances

  • Antineoplastic Agents
  • Apoptosis Regulatory Proteins
  • alpha Catenin
  • fas Receptor
  • Cisplatin