Cytotoxicity of nitric oxide is alleviated by zinc-mediated expression of antioxidant genes

Mi J. Chung, Christer Hogstrand, Sung-Joon Lee

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Metallothioneins (MTs) are small, cysteine-rich zinc binding proteins that are powerful antioxidants. In this study, we investigated the interaction between zinc, MTs, and other components of the antioxidant defense system in HepG2 cells. Cells were preincubated with zinc and then exposed to sodium nitroprusside (SNP), a nitric oxide (NO) donor. Both zinc pretreatment and SNP exposure separately induced transcription of MT genes (MT1A, MT2A, MT1E, MT1X), as measured using real time-polymerase chain reaction (PCR) after reverse transcription (RT). Pretreatment of HepG2 cells with zinc sulfate (ZnSO 4) followed by SNP exposure caused MT and glucose-6-phosphate dehydrogenase (G6PD) mRNA levels to increase more than in cells only exposed to SNP. However, when cells were incubated with N,N,N′,N′-tetrakis(2- pyridylmethyl)ethylenediamine (TPEN), a membrane-permeant Zn2+ chelator, the stimulation of MT transcription by SNP was blocked, suggesting that SNP-induced upregulation of these genes is zinc-dependent. Human glutathione-S-transferase (hGSTA1) and G6PD mRNA levels in the cells treated with 5 μM TPEN decreased. Additionally, the induction of MT by SNP after zinc pretreatment appears to be mediated by metal-activated transcription factor-1 (MTF-1), which is induced by labile zinc in the cytosol. SNP cytotoxicity was inhibited by preincubation with zinc. Taken together, these results suggest that NO plays an important role in regulation of cellular zinc homeostasis and that NO-mediated release of protein-bound Zn2+ may be an important signal in antioxidant defense.

Original languageEnglish
Pages (from-to)1555-1563
Number of pages9
JournalExperimental Biology and Medicine
Volume231
Issue number9
Publication statusPublished - 2006 Oct 17

Fingerprint

Nitroprusside
Cytotoxicity
Zinc
Nitric Oxide
Antioxidants
Genes
Gene Expression
ethylenediamine
Transcription
Glucosephosphate Dehydrogenase
Hep G2 Cells
Zinc Sulfate
Messenger RNA
Nitric Oxide Donors
Metallothionein
Polymerase chain reaction
Chelating Agents
Glutathione Transferase
Cytosol
Reverse Transcription

Keywords

  • Antioxidant gene
  • Metallothioneins
  • N,N,N′N′-tetrakis(2-pyridylmethyl)ethylenediamine
  • Sodium nitroprusside
  • Zinc

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Cytotoxicity of nitric oxide is alleviated by zinc-mediated expression of antioxidant genes. / Chung, Mi J.; Hogstrand, Christer; Lee, Sung-Joon.

In: Experimental Biology and Medicine, Vol. 231, No. 9, 17.10.2006, p. 1555-1563.

Research output: Contribution to journalArticle

@article{eed1af8302254456a94981afc84e3e09,
title = "Cytotoxicity of nitric oxide is alleviated by zinc-mediated expression of antioxidant genes",
abstract = "Metallothioneins (MTs) are small, cysteine-rich zinc binding proteins that are powerful antioxidants. In this study, we investigated the interaction between zinc, MTs, and other components of the antioxidant defense system in HepG2 cells. Cells were preincubated with zinc and then exposed to sodium nitroprusside (SNP), a nitric oxide (NO) donor. Both zinc pretreatment and SNP exposure separately induced transcription of MT genes (MT1A, MT2A, MT1E, MT1X), as measured using real time-polymerase chain reaction (PCR) after reverse transcription (RT). Pretreatment of HepG2 cells with zinc sulfate (ZnSO 4) followed by SNP exposure caused MT and glucose-6-phosphate dehydrogenase (G6PD) mRNA levels to increase more than in cells only exposed to SNP. However, when cells were incubated with N,N,N′,N′-tetrakis(2- pyridylmethyl)ethylenediamine (TPEN), a membrane-permeant Zn2+ chelator, the stimulation of MT transcription by SNP was blocked, suggesting that SNP-induced upregulation of these genes is zinc-dependent. Human glutathione-S-transferase (hGSTA1) and G6PD mRNA levels in the cells treated with 5 μM TPEN decreased. Additionally, the induction of MT by SNP after zinc pretreatment appears to be mediated by metal-activated transcription factor-1 (MTF-1), which is induced by labile zinc in the cytosol. SNP cytotoxicity was inhibited by preincubation with zinc. Taken together, these results suggest that NO plays an important role in regulation of cellular zinc homeostasis and that NO-mediated release of protein-bound Zn2+ may be an important signal in antioxidant defense.",
keywords = "Antioxidant gene, Metallothioneins, N,N,N′N′-tetrakis(2-pyridylmethyl)ethylenediamine, Sodium nitroprusside, Zinc",
author = "Chung, {Mi J.} and Christer Hogstrand and Sung-Joon Lee",
year = "2006",
month = "10",
day = "17",
language = "English",
volume = "231",
pages = "1555--1563",
journal = "Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)",
issn = "1535-3702",
publisher = "Society for Experimental Biology and Medicine",
number = "9",

}

TY - JOUR

T1 - Cytotoxicity of nitric oxide is alleviated by zinc-mediated expression of antioxidant genes

AU - Chung, Mi J.

AU - Hogstrand, Christer

AU - Lee, Sung-Joon

PY - 2006/10/17

Y1 - 2006/10/17

N2 - Metallothioneins (MTs) are small, cysteine-rich zinc binding proteins that are powerful antioxidants. In this study, we investigated the interaction between zinc, MTs, and other components of the antioxidant defense system in HepG2 cells. Cells were preincubated with zinc and then exposed to sodium nitroprusside (SNP), a nitric oxide (NO) donor. Both zinc pretreatment and SNP exposure separately induced transcription of MT genes (MT1A, MT2A, MT1E, MT1X), as measured using real time-polymerase chain reaction (PCR) after reverse transcription (RT). Pretreatment of HepG2 cells with zinc sulfate (ZnSO 4) followed by SNP exposure caused MT and glucose-6-phosphate dehydrogenase (G6PD) mRNA levels to increase more than in cells only exposed to SNP. However, when cells were incubated with N,N,N′,N′-tetrakis(2- pyridylmethyl)ethylenediamine (TPEN), a membrane-permeant Zn2+ chelator, the stimulation of MT transcription by SNP was blocked, suggesting that SNP-induced upregulation of these genes is zinc-dependent. Human glutathione-S-transferase (hGSTA1) and G6PD mRNA levels in the cells treated with 5 μM TPEN decreased. Additionally, the induction of MT by SNP after zinc pretreatment appears to be mediated by metal-activated transcription factor-1 (MTF-1), which is induced by labile zinc in the cytosol. SNP cytotoxicity was inhibited by preincubation with zinc. Taken together, these results suggest that NO plays an important role in regulation of cellular zinc homeostasis and that NO-mediated release of protein-bound Zn2+ may be an important signal in antioxidant defense.

AB - Metallothioneins (MTs) are small, cysteine-rich zinc binding proteins that are powerful antioxidants. In this study, we investigated the interaction between zinc, MTs, and other components of the antioxidant defense system in HepG2 cells. Cells were preincubated with zinc and then exposed to sodium nitroprusside (SNP), a nitric oxide (NO) donor. Both zinc pretreatment and SNP exposure separately induced transcription of MT genes (MT1A, MT2A, MT1E, MT1X), as measured using real time-polymerase chain reaction (PCR) after reverse transcription (RT). Pretreatment of HepG2 cells with zinc sulfate (ZnSO 4) followed by SNP exposure caused MT and glucose-6-phosphate dehydrogenase (G6PD) mRNA levels to increase more than in cells only exposed to SNP. However, when cells were incubated with N,N,N′,N′-tetrakis(2- pyridylmethyl)ethylenediamine (TPEN), a membrane-permeant Zn2+ chelator, the stimulation of MT transcription by SNP was blocked, suggesting that SNP-induced upregulation of these genes is zinc-dependent. Human glutathione-S-transferase (hGSTA1) and G6PD mRNA levels in the cells treated with 5 μM TPEN decreased. Additionally, the induction of MT by SNP after zinc pretreatment appears to be mediated by metal-activated transcription factor-1 (MTF-1), which is induced by labile zinc in the cytosol. SNP cytotoxicity was inhibited by preincubation with zinc. Taken together, these results suggest that NO plays an important role in regulation of cellular zinc homeostasis and that NO-mediated release of protein-bound Zn2+ may be an important signal in antioxidant defense.

KW - Antioxidant gene

KW - Metallothioneins

KW - N,N,N′N′-tetrakis(2-pyridylmethyl)ethylenediamine

KW - Sodium nitroprusside

KW - Zinc

UR - http://www.scopus.com/inward/record.url?scp=33749589959&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749589959&partnerID=8YFLogxK

M3 - Article

VL - 231

SP - 1555

EP - 1563

JO - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)

JF - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)

SN - 1535-3702

IS - 9

ER -