Distinct protective mechanisms of HO-1 and HO-2 against hydroperoxide-induced cytotoxicity

Yun Sook Kim, Hean Zhuang, Raymond C Koehler, Sylvain Doré

Research output: Contribution to journalArticle

Abstract

Heme oxygenases (HO-1 and HO-2) catalyze the NADPH-cytochrome P 450 reductase (CPR)-dependent degradation of heme into iron, carbon monoxide, and biliverdin, which is reduced into bilirubin. Under basal conditions, HO-1 is often undetected and can be induced by numerous stress conditions. Although HO-2 is constitutively expressed, its activity appears to be regulated by post-translational modifications. HO activity has been associated with cellular protection, by which it degrades heme, a prooxidant, into bioactive metabolites. Under given circumstances, overexpression of HO-1 can render cells more sensitive to free radicals. Here, we investigated the properties of human HO isoforms that protect against oxidative stress. Considering that CPR can be a limiting factor for optimal HO activity, we tested stable HO-1 and HO-2 cell lines that derived from the CPR cells. Results indicate that the HO-1 and HO-2 cells are more resistant than controls to hemin and to the organic tert-butyl hydroperoxide, t-BuOOH. However, HO-1 cells are less resistant than HO-2 cells to hydrogen peroxide (H 2O 2). The levels of oxidatively modified proteins of HO-1 and HO-2 cells in response to t-BuOOH toxicity are identical, but the level of oxidatively modified proteins of HO-2 cells is less than that of HO-1 cells in response to H 2O 2 toxicity. Performing subcellular fractionations revealed that HO-2 and CPR are found together in the microsomal fractions, whereas HO-1 is partially present in the microsome and also found in other fractions, such as the cytosol. These same findings were observed in non-transfected primary neurons where HO-1 proteins were chemically induced with 15-deoxy-Δ 12,14-prostaglandin J 2 (15dPGJ 2). The differences in subcellular localization of HO-1 and HO-2 could explain some of the discrepancies in their cellular activity and enzymatic protective mechanisms.

Original languageEnglish (US)
Pages (from-to)85-92
Number of pages8
JournalFree Radical Biology and Medicine
Volume38
Issue number1
DOIs
StatePublished - Jan 1 2005

Fingerprint

NADPH-Ferrihemoprotein Reductase
Cytotoxicity
Hydrogen Peroxide
Toxicity
Biliverdine
tert-Butylhydroperoxide
Heme Oxygenase (Decyclizing)
Hemin
Proteins
Oxidative stress
Carbon Monoxide
Fractionation
Metabolites
Heme
Bilirubin
Neurons
Free Radicals
Prostaglandins
Protein Isoforms
Iron

Keywords

  • Cytochrome P reductase
  • Endoplasmic reticulum
  • Free radicals
  • Heme oxygenase
  • Microsome
  • Prostaglandins
  • Subcellular localization

ASJC Scopus subject areas

  • Medicine(all)
  • Toxicology
  • Clinical Biochemistry

Cite this

Distinct protective mechanisms of HO-1 and HO-2 against hydroperoxide-induced cytotoxicity. / Kim, Yun Sook; Zhuang, Hean; Koehler, Raymond C; Doré, Sylvain.

In: Free Radical Biology and Medicine, Vol. 38, No. 1, 01.01.2005, p. 85-92.

Research output: Contribution to journalArticle

@article{1c379c1855774d83b5947f2a14c5ac38,
title = "Distinct protective mechanisms of HO-1 and HO-2 against hydroperoxide-induced cytotoxicity",
abstract = "Heme oxygenases (HO-1 and HO-2) catalyze the NADPH-cytochrome P 450 reductase (CPR)-dependent degradation of heme into iron, carbon monoxide, and biliverdin, which is reduced into bilirubin. Under basal conditions, HO-1 is often undetected and can be induced by numerous stress conditions. Although HO-2 is constitutively expressed, its activity appears to be regulated by post-translational modifications. HO activity has been associated with cellular protection, by which it degrades heme, a prooxidant, into bioactive metabolites. Under given circumstances, overexpression of HO-1 can render cells more sensitive to free radicals. Here, we investigated the properties of human HO isoforms that protect against oxidative stress. Considering that CPR can be a limiting factor for optimal HO activity, we tested stable HO-1 and HO-2 cell lines that derived from the CPR cells. Results indicate that the HO-1 and HO-2 cells are more resistant than controls to hemin and to the organic tert-butyl hydroperoxide, t-BuOOH. However, HO-1 cells are less resistant than HO-2 cells to hydrogen peroxide (H 2O 2). The levels of oxidatively modified proteins of HO-1 and HO-2 cells in response to t-BuOOH toxicity are identical, but the level of oxidatively modified proteins of HO-2 cells is less than that of HO-1 cells in response to H 2O 2 toxicity. Performing subcellular fractionations revealed that HO-2 and CPR are found together in the microsomal fractions, whereas HO-1 is partially present in the microsome and also found in other fractions, such as the cytosol. These same findings were observed in non-transfected primary neurons where HO-1 proteins were chemically induced with 15-deoxy-Δ 12,14-prostaglandin J 2 (15dPGJ 2). The differences in subcellular localization of HO-1 and HO-2 could explain some of the discrepancies in their cellular activity and enzymatic protective mechanisms.",
keywords = "Cytochrome P reductase, Endoplasmic reticulum, Free radicals, Heme oxygenase, Microsome, Prostaglandins, Subcellular localization",
author = "Kim, {Yun Sook} and Hean Zhuang and Koehler, {Raymond C} and Sylvain Dor{\'e}",
year = "2005",
month = "1",
day = "1",
doi = "10.1016/j.freeradbiomed.2004.09.031",
language = "English (US)",
volume = "38",
pages = "85--92",
journal = "Free Radical Biology and Medicine",
issn = "0891-5849",
publisher = "Elsevier Inc.",
number = "1",

}

TY - JOUR

T1 - Distinct protective mechanisms of HO-1 and HO-2 against hydroperoxide-induced cytotoxicity

AU - Kim, Yun Sook

AU - Zhuang, Hean

AU - Koehler, Raymond C

AU - Doré, Sylvain

PY - 2005/1/1

Y1 - 2005/1/1

N2 - Heme oxygenases (HO-1 and HO-2) catalyze the NADPH-cytochrome P 450 reductase (CPR)-dependent degradation of heme into iron, carbon monoxide, and biliverdin, which is reduced into bilirubin. Under basal conditions, HO-1 is often undetected and can be induced by numerous stress conditions. Although HO-2 is constitutively expressed, its activity appears to be regulated by post-translational modifications. HO activity has been associated with cellular protection, by which it degrades heme, a prooxidant, into bioactive metabolites. Under given circumstances, overexpression of HO-1 can render cells more sensitive to free radicals. Here, we investigated the properties of human HO isoforms that protect against oxidative stress. Considering that CPR can be a limiting factor for optimal HO activity, we tested stable HO-1 and HO-2 cell lines that derived from the CPR cells. Results indicate that the HO-1 and HO-2 cells are more resistant than controls to hemin and to the organic tert-butyl hydroperoxide, t-BuOOH. However, HO-1 cells are less resistant than HO-2 cells to hydrogen peroxide (H 2O 2). The levels of oxidatively modified proteins of HO-1 and HO-2 cells in response to t-BuOOH toxicity are identical, but the level of oxidatively modified proteins of HO-2 cells is less than that of HO-1 cells in response to H 2O 2 toxicity. Performing subcellular fractionations revealed that HO-2 and CPR are found together in the microsomal fractions, whereas HO-1 is partially present in the microsome and also found in other fractions, such as the cytosol. These same findings were observed in non-transfected primary neurons where HO-1 proteins were chemically induced with 15-deoxy-Δ 12,14-prostaglandin J 2 (15dPGJ 2). The differences in subcellular localization of HO-1 and HO-2 could explain some of the discrepancies in their cellular activity and enzymatic protective mechanisms.

AB - Heme oxygenases (HO-1 and HO-2) catalyze the NADPH-cytochrome P 450 reductase (CPR)-dependent degradation of heme into iron, carbon monoxide, and biliverdin, which is reduced into bilirubin. Under basal conditions, HO-1 is often undetected and can be induced by numerous stress conditions. Although HO-2 is constitutively expressed, its activity appears to be regulated by post-translational modifications. HO activity has been associated with cellular protection, by which it degrades heme, a prooxidant, into bioactive metabolites. Under given circumstances, overexpression of HO-1 can render cells more sensitive to free radicals. Here, we investigated the properties of human HO isoforms that protect against oxidative stress. Considering that CPR can be a limiting factor for optimal HO activity, we tested stable HO-1 and HO-2 cell lines that derived from the CPR cells. Results indicate that the HO-1 and HO-2 cells are more resistant than controls to hemin and to the organic tert-butyl hydroperoxide, t-BuOOH. However, HO-1 cells are less resistant than HO-2 cells to hydrogen peroxide (H 2O 2). The levels of oxidatively modified proteins of HO-1 and HO-2 cells in response to t-BuOOH toxicity are identical, but the level of oxidatively modified proteins of HO-2 cells is less than that of HO-1 cells in response to H 2O 2 toxicity. Performing subcellular fractionations revealed that HO-2 and CPR are found together in the microsomal fractions, whereas HO-1 is partially present in the microsome and also found in other fractions, such as the cytosol. These same findings were observed in non-transfected primary neurons where HO-1 proteins were chemically induced with 15-deoxy-Δ 12,14-prostaglandin J 2 (15dPGJ 2). The differences in subcellular localization of HO-1 and HO-2 could explain some of the discrepancies in their cellular activity and enzymatic protective mechanisms.

KW - Cytochrome P reductase

KW - Endoplasmic reticulum

KW - Free radicals

KW - Heme oxygenase

KW - Microsome

KW - Prostaglandins

KW - Subcellular localization

UR - http://www.scopus.com/inward/record.url?scp=10344219952&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=10344219952&partnerID=8YFLogxK

U2 - 10.1016/j.freeradbiomed.2004.09.031

DO - 10.1016/j.freeradbiomed.2004.09.031

M3 - Article

C2 - 15589375

AN - SCOPUS:10344219952

VL - 38

SP - 85

EP - 92

JO - Free Radical Biology and Medicine

JF - Free Radical Biology and Medicine

SN - 0891-5849

IS - 1

ER -