Activation of the Nrf2 pathway, but decreased γ-glutamylcysteine synthetase heavy subunit chain levels and caspase-3-dependent apoptosis during exposure of primary mouse hepatocytes to diphenylarsinic acid

Daigo Sumi, Aiko Manji, Yasuhiro Shinkai, Takashi Toyama, Yoshito Kumagai

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Diphenylarsinic acid (DPAsV) is a degradation product of chemical warfare agents, over which there has been a public outcry in the Kamisu Area of Ibaraki Prefecture in Japan. In this study, we investigated the cytotoxicity of and cellular response to DPAsV in primary mouse hepatocytes. Exposure of the hepatocytes to DPAsV resulted in cell damage accompanied by cellular accumulation of DPAsV in a time-dependent manner. The cell death caused by DPAsV was attributable to apoptosis. DPAsV activated a basic leucine-zipper transcription factor Nrf2 as determined by the nuclear translocation of Nrf2, anti-oxidant response element (ARE)-dependent luciferase activity, and upregulation of downstream gene products. However, γ-glutamylcysteine synthetase heavy subunit chain (γ-GCSH), which is regulated by Nrf2, underwent cleavage by activated caspase-3 to a 17 kDa fragment, leading to a minimal level of constitutive γ-GCSH expression 72 h following the exposure (25 μM). Experiments with cycloheximide revealed that the DPAsV-mediated reduction in γ-GCSH was due to a post-translational modification. The results suggest that DPAsV causes caspase-3-dependent cleavage of γ-GCSH regardless of Nrf2 activation in primary mouse hepatocytes.

Original languageEnglish
Pages (from-to)218-224
Number of pages7
JournalToxicology and Applied Pharmacology
Volume223
Issue number3
DOIs
Publication statusPublished - 2007 Sep 15
Externally publishedYes

Keywords

  • Apoptosis
  • Arsenic
  • Glutathione
  • Hepatotoxicity

ASJC Scopus subject areas

  • Toxicology
  • Pharmacology

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