Activation of Nrf2 and accumulation of ubiquitinated A170 by arsenic in osteoblasts

Junko Aono, Toru Yanagawa, Ken Itoh, Baojie Li, Hiroshi Yoshida, Yoshito Kumagai, Masayuki Yamamoto, Tetsuro Ishii

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

Sub-lethal levels of arsenic induce upregulation of stress proteins. We here report for the first time that inorganic arsenic activates the transcription factor Nrf2, which controls the expression of oxidative stress-induced proteins. Treatment of cultured MC3T3-E1 osteoblasts with arsenite or arsenate induced increase of Nrf2, followed by transcriptional activation of target genes encoding HO-1, Prx I, and A170. We found that arsenate (200-800μM) only slightly increased the normal 60kDa A170 protein but markedly increased higher molecular mass forms of A170 (HMM-A170) that appeared as smeared bands. Arsenate also markedly increased ubiquitin-conjugated cellular proteins, suggesting that HMM-A170 was one of the poly-ubiquitinated proteins. Arsenite (50-100μM) also induced accumulation of HMM-A170 and ubiquitin-conjugated proteins. These results provide the first direct evidence that toxic arsenics impair the normal function of A170. Our findings provide a potential diagnostic tool for monitoring biotoxicity in cells and tissues in response to arsenic compounds.

Original languageEnglish
Pages (from-to)271-277
Number of pages7
JournalBiochemical and biophysical research communications
Volume305
Issue number2
DOIs
Publication statusPublished - 2003 May 30

Keywords

  • A170
  • Arsenic
  • Heme oxygenase-1
  • Nrf2
  • Osteoblast
  • Peroxiredoxin I
  • Stress protein
  • Ubiquitin

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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