Cell Biology and Toxicology

, Volume 26, Issue 3, pp 239–254

Characterization of ochratoxin A-induced apoptosis in primary rat hepatocytes

  • Martin Chopra
  • Pascal Link
  • Christine Michels
  • Dieter Schrenk
Article

DOI: 10.1007/s10565-009-9131-0

Cite this article as:
Chopra, M., Link, P., Michels, C. et al. Cell Biol Toxicol (2010) 26: 239. doi:10.1007/s10565-009-9131-0
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Abstract

The main target organ of the mycotoxin ochratoxin A (OTA) in mammals is the kidney but OTA has also been shown to be hepatotoxic in rats and to induce tumors in mouse liver. Even at very low concentrations, OTA causes perturbations of cellular signaling pathways as well as enhanced apoptosis. OTA has been extensively studied in kidney cell systems. Since this substance also affects liver health, we focused our work on apoptosis-related events induced by OTA in primary rat hepatocytes. We performed pathway-specific polymerase chain reaction arrays to assess the expression of genes involved in apoptosis. Treatment with 1 µM OTA for 24 h caused marked changes in apoptosis-related gene expression. Genes as apaf1, bad, caspase 7, polb (DNA polymerase beta, performs base excision repair), and p53, which are marker genes for DNA damage, were upregulated. FAS and faslg were also markedly induced by treatment with OTA. Treatment of hepatocytes with OTA led to a concentration-dependent inhibition of protein biosynthesis. Apoptosis-inducing factor was released from mitochondria following OTA treatment; the mycotoxin induced the activity of caspases 8, 9, and 3/7 and caused chromatin condensation and fragmentation. Caspase inhibition led to a significant but not complete reduction of OTA-induced apoptosis. Our data suggest that not only OTA leads to p53-dependent apoptosis in rat hepatocytes but it also hints to other mechanisms, independent of caspase activation or protein biosynthesis, being involved.

Keywords

ApoptosisCaspasesHepatocytesMycotoxinsOchratoxin A

Abbreviations

AIF

Apoptosis-inducing factor

CAD

Caspase-activated DNase

CHX

Cycloheximide

DAPI

4′, 6-Diamidino-2-phenylindole

DMSO

Dimethyl sulfoxide

DTT

Dithiothreitol

DFF

DNA fragmentation factor

ICAD

Inhibitor of caspase-activated DNase

OTA

Ochratoxin A

PIPES

Piperazine-N,N′-bis(2-ethanesulfonic acid)

PBS

Phosphate-buffered saline

PVDF

Polyvinylidene fluoride

qPCR

Quantitative polymerase chain reaction

ROS

Reactive oxygen species

cT

Threshold cycle

TBS

Tris-buffered saline

VDAC

Voltage-dependent anion channel

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Martin Chopra
    • 1
  • Pascal Link
    • 1
  • Christine Michels
    • 1
  • Dieter Schrenk
    • 1
  1. 1.Institute of Food Chemistry and ToxicologyUniversity of KaiserslauternKaiserslauternGermany