Extracellular superoxide dismutase (EC-SOD) is the most abundant extracellular antioxidant enzyme in the lung and current studies indicates that EC-SOD plays a key role in the pathogenesis of oxidant-induced pulmonary and vascular injury and resulting inflammation. We and others have shown that EC-SOD overexpression in the lungs of mice protects the lungs against acute lung injury from hyperoxia exposure, residual oil fly ash, influenza pneumonia, hemorrhage induced lung injury, radiation pneumonitis, bleomycin-induced lung fibrosis and preserves lung development in a neonatal model of hyperoxia. In cardiovascular disease models, EC-SOD protects against ischemia-reperfusion injury, attenuates hypertension, and specific polymorphisms impart a significant increased risk for ischemic heart disease. Despite this work, the precise mechanism of EC-SOD's protective role in these disease processes remains unclear. Recently we have begun to unravel factors important in regulating EC-SOD tissue and cell-specific expression. In this competing renewal application, we will build on our most recent findings that have begun to explore molecular pathways that control EC-SOD gene expression. Based on our initial characterization of the human and mouse EC-SOD genes, we now hypothesize that EC-SOD transcriptional expression is regulated by a family of transcription factors (Ets, MZF-1, Kruppel, and Sp1/Sp3) interacting at a proximal and distal promoter element located in the 5'-untranslated region of the murine EC-SOD gene. It is further proposed that the activity of these elements is modulated by epigenetic processes including histone acetylation and methylation. To test these hypotheses, we propose 3 specific aims.
Aim 1 will examine the contribution and identification of cis-elements and trans-activating factors regulating basal and cell specific EC-SOD expression in the lung.
In Aim 2, we will identify and characterize transcription factor elements responsible for modulation of EC-SOD gene transcription.
In Aim 3 will use a novel in vivo bioluminescence imaging system to examine the functional and spatial gene expression profile utilizing the newly discovered EC-SOD proximal and distal promoter elements in transgenic mice. It is anticipated that this work will provide new insights into our understanding of molecular mechanisms involved in the regulation of EC-SOD gene expression. This could lead to novel pharmacologic strategies for augmenting endogenous EC-SOD levels in the lungs and other tissues, which would be predicted to reduce extracellular oxidative stress and attenuate lung disease processes.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL064894-08
Application #
7650356
Study Section
Lung Cellular, Molecular, and Immunobiology Study Section (LCMI)
Program Officer
Harabin, Andrea L
Project Start
2000-09-01
Project End
2012-06-30
Budget Start
2009-07-01
Budget End
2012-06-30
Support Year
8
Fiscal Year
2009
Total Cost
$359,270
Indirect Cost
Name
University of Louisville
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
057588857
City
Louisville
State
KY
Country
United States
Zip Code
40292
Zelko, Igor N; Stepp, Marcus W; Folz, Rodney J (2013) A bioluminescent transgenic mouse model: real-time in vivo imaging of antioxidant EC-SOD gene expression and regulation by interferon gamma. Gene 530:75-82
Zelko, Igor N; Stepp, Marcus W; Vorst, Alan L et al. (2011) Histone acetylation regulates the cell-specific and interferon-ýý-inducible expression of extracellular superoxide dismutase in human pulmonary arteries. Am J Respir Cell Mol Biol 45:953-61
Zelko, Igor N; Folz, Rodney J (2010) Extracellular superoxide dismutase attenuates release of pulmonary hyaluronan from the extracellular matrix following bleomycin exposure. FEBS Lett 584:2947-52
Zelko, Igor N; Mueller, Michael R; Folz, Rodney J (2010) CpG methylation attenuates Sp1 and Sp3 binding to the human extracellular superoxide dismutase promoter and regulates its cell-specific expression. Free Radic Biol Med 48:895-904
Zelko, Igor N; Mueller, Michael R; Folz, Rodney J (2008) Transcription factors sp1 and sp3 regulate expression of human extracellular superoxide dismutase in lung fibroblasts. Am J Respir Cell Mol Biol 39:243-51
Liu, John Q; Zelko, Igor N; Erbynn, Efua M et al. (2006) Hypoxic pulmonary hypertension: role of superoxide and NADPH oxidase (gp91phox). Am J Physiol Lung Cell Mol Physiol 290:L2-10
Liu, John Q; Yang, Dennis; Folz, Rodney J (2006) A novel bronchial ring bioassay for the evaluation of small airway smooth muscle function in mice. Am J Physiol Lung Cell Mol Physiol 291:L281-8
Liu, John Q; Erbynn, Efua M; Folz, Rodney J (2005) Chronic hypoxia-enhanced murine pulmonary vasoconstriction: role of superoxide and gp91phox. Chest 128:594S-596S
Liu, John Q; Zelko, Igor N; Folz, Rodney J (2004) Reoxygenation-induced constriction in murine coronary arteries: the role of endothelial NADPH oxidase (gp91phox) and intracellular superoxide. J Biol Chem 279:24493-7
Liu, John Q; Folz, Rodney J (2004) Extracellular superoxide enhances 5-HT-induced murine pulmonary artery vasoconstriction. Am J Physiol Lung Cell Mol Physiol 287:L111-8

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