The beneficial effects of supplemental oxygen to reduce tissue hypoxia in patients suffering from respiratory distress are well known. Unfortunately, oxygen is reduced to cytotoxic reactive oxygen species that damage DNA, proteins and lipids resulting in cell injury, death and inflammation. DNA repair and replication occur during recovery in room air as injured and dead cells are replaced. Failure to appropriately repair and proliferate can lead to cell death, inflammation, fibrosis and chronic lung disease. Therefore, identifying molecules that regulate DNA repair and replication is important for improving clinical outcomes for patients treated with hyperoxia. Recent studies have shown that hyperoxia activates the DNA damage-dependent pathway involving the p53 tumor suppressor. P53 accumulates in cells with damaged DNA and increases the expression of the cyclin-dependent kinase inhibitor p21Cip1/WAF1 (hereafter p21) or the proapoptotic gene bax. Studies using p21-deficient mice and cell lines reveal that p21 inhibits proliferation, thereby reducing cell death, inflammation and mortality. Surprisingly, hyperoxia also inhibited the expression of the DNA repair protein AP-endonuclease when p21 was induced, but not when it was absent. APE is also redox factor (Ref)-1, which reduces oxidized forms of transcription factors, such as p53. This suggests that p21 protects cells from oxidant damage by preventing DNA repair commitment when DNA is being damaged and regulates p53-dependent transcription. The studies proposed in Aim 1 will determine whether p21-deficient cells have more DNA fragmentation during hyperoxia due to increased repair activity, Aim 2 will determine whether APE/Ref-1 regulates DNA repair and p53 activity, and Aim 3 will determine whether p53-dependent apoptosis promotes tissue repair in the absence of p21. A better understanding of how p21 protects cells from oxygen-induced damage has therapeutic value for treatment of lung injury caused by hyperoxia as well as other as other inhaled pollutants that produce oxidant free radicals.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL067392-01A2
Application #
6508966
Study Section
Lung Biology and Pathology Study Section (LBPA)
Program Officer
Harabin, Andrea L
Project Start
2002-07-01
Project End
2006-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
1
Fiscal Year
2002
Total Cost
$354,375
Indirect Cost
Name
University of Rochester
Department
Pediatrics
Type
Schools of Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
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Resseguie, Emily A; Staversky, Rhonda J; Brookes, Paul S et al. (2015) Hyperoxia activates ATM independent from mitochondrial ROS and dysfunction. Redox Biol 5:176-85
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Yee, Min; Buczynski, Bradley W; O'Reilly, Michael A (2014) Neonatal hyperoxia stimulates the expansion of alveolar epithelial type II cells. Am J Respir Cell Mol Biol 50:757-66
Kalifa, Lidza; Gewandter, Jennifer S; Staversky, Rhonda J et al. (2014) DNA double-strand breaks activate ATM independent of mitochondrial dysfunction in A549 cells. Free Radic Biol Med 75:30-9
Buczynski, Bradley W; Maduekwe, Echezona T; O'Reilly, Michael A (2013) The role of hyperoxia in the pathogenesis of experimental BPD. Semin Perinatol 37:69-78
O'Reilly, Michael A (2012) Angiotensin II: tapping the cell cycle machinery to kill endothelial cells. Am J Physiol Lung Cell Mol Physiol 303:L575-6
Gewandter, Jennifer S; Bambara, Robert A; O'Reilly, Michael A (2011) The RNA surveillance protein SMG1 activates p53 in response to DNA double-strand breaks but not exogenously oxidized mRNA. Cell Cycle 10:2561-7
Wu, Yu-Chieh M; O'Reilly, Michael A (2011) Bcl-X(L) is the primary mediator of p21 protection against hyperoxia-induced cell death. Exp Lung Res 37:82-91

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