Nitric oxide (NO) is produced in mammalian cells by several NO synthases, including an inducible form with high output during inflammation. Since NO may contribute to carcinogenesis and age- related neurodegeneration, we wish to understand how mammalian cells counteract NO toxicity. We have identified a group of 12 proteins induced in normal human fibroblasts by exposure to subtoxic levels of NO, including the antioxidant enzyme heme oxygenase 1 (HO-1). We have shown that the induction of HO-1 mRNA occurs via NO-dependent changes in its stability. We will explore the mechanism of this regulation and try to define the signal transduction pathway for post-transcriptional control of HO-1. Other genes (e.g., MAP kinase phosphatase MKP-1/CL100) are controlled transcriptionally, and we will test specific transcription regulators for their roles in this expression. We have identified an adaptive resistance to NO in the rodent motor neurons: cells exposed to low-level NO that induces HO-1 become resistant to much higher (usually cytotoxic) levels of NO. We will characterize this response in various cell types by identifying NO-inducible genes and determining their roles in protection against NO-mediated toxicity. HO-1 knockout mice will allow us to define the defensive role of HO-1 in fibroblasts, neurons, and other tissues. This project involves parallel efforts to follow biochemical markers of nitric oxide damage (e.g., nitrotyrosine), to use genetics to establish the role of HO-1 in inducible resistance to NO, to elucidate regulatory and signal transduction pathways, and to identify and clone novel defense genes for NO resistance.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA082737-02
Application #
6173925
Study Section
Chemical Pathology Study Section (CPA)
Program Officer
Okano, Paul
Project Start
1999-09-17
Project End
2004-06-30
Budget Start
2000-07-01
Budget End
2001-06-30
Support Year
2
Fiscal Year
2000
Total Cost
$275,293
Indirect Cost
Name
Harvard University
Department
Genetics
Type
Schools of Public Health
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02115
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Leautaud, Veronica; Demple, Bruce (2007) Regulation of heme oxygenase-1 mRNA deadenylation and turnover in NIH3T3 cells by nitrosative or alkylation stress. BMC Mol Biol 8:116
Johnson, W Evan; Li, Cheng; Rabinovic, Ariel (2007) Adjusting batch effects in microarray expression data using empirical Bayes methods. Biostatistics 8:118-27
Reiter, Tiffany A; Pang, Bo; Dedon, Peter et al. (2006) Resistance to nitric oxide-induced necrosis in heme oxygenase-1 overexpressing pulmonary epithelial cells associated with decreased lipid peroxidation. J Biol Chem 281:36603-12
Reiter, Tiffany A; Demple, Bruce (2005) Carbon monoxide mediates protection against nitric oxide toxicity in HeLa cells. Free Radic Biol Med 39:1075-88
McLaughlin, Laura M; Demple, Bruce (2005) Nitric oxide-induced apoptosis in lymphoblastoid and fibroblast cells dependent on the phosphorylation and activation of p53. Cancer Res 65:6097-104
Bishop, Amy; Yet, Shaw-Fang; Lee, Mu-En et al. (2004) A key role for heme oxygenase-1 in nitric oxide resistance in murine motor neurons and glia. Biochem Biophys Res Commun 325:3-9
Mitsumoto, Minako; Mitsumoto, Atsushi; Demple, Bruce (2003) Nitric oxide-mediated upregulation of the TGF-beta-inducible early response gene-1 (TIEG1) in human fibroblasts by mRNA stabilization independent of TGF-beta. Free Radic Biol Med 34:1607-13
Bouton, C; Demple, B (2000) Nitric oxide-inducible expression of heme oxygenase-1 in human cells. Translation-independent stabilization of the mRNA and evidence for direct action of nitric oxide. J Biol Chem 275:32688-93