Particulate air pollution increases respiratory disease morbidity and mortality, especially in individuals with inflammatory lung disease. Mechanisms of particle health effects at the cellular level are poorly understood. The general hypothesis of this proposal is that particle toxicity operates through oxidant-dependent mechanisms: 1) derived from particle components, 2) targeted to specific intracellular compartments, and 3) enhanced by pre-existing inflammation. Our strategy is to identify the cellular target(s) of PM mediated oxidant stress and to quantify the biological impact of blocking oxidant production at each one of the affected targets.
Aim 1 will test the hypothesis that particles cause inflammation and toxicity by oxidant-dependent mechanisms. We will measure concentrated particles (CAPs) ability to increase ROS in vivo and in vitro, determine CAPs effects on production and detoxification of oxidants, and evaluate the biological impact of CAPs-induced oxidant stress. Treatment with antioxidants will test the role of oxidant mediators in CAPs biological responses.
Aim 2 will test the hypothesis that particles cause oxidant stress by direct interaction with cellular targets. We will test CAPs effect on H2O2 production in cells treated with specific inhibitors, in subcellular fractions supplemented with their optimal substrates, and in genetically altered mice lacking or overexpressing critical antioxidants in different cellular compartments.
Aim 3 will test the postulate that soluble components of CAPs cause oxidant and biological responses in epithelial cells. Water-soluble, insoluble, and organic fractions of CAPs will be assessed for ability to cause oxidant and biological responses in vitro. The variability in responses of different days' CAPs exposures will be exploited to identify bioactive compositional and source factors.
Aim 4 will test the hypothesis that particles cause enhanced oxidant generation in inflammation-primed epithelial cells and whole lungs. We will quantify CAPs-induced increases in H2O2 and cellular damage in naive and TNF-primed AT II cells. To identify the cellular target of CAPs and TNF we will use specific inhibitors of suspected signaling steps. Treatment with antioxidants will test the role of oxidant mediators. The role of TNF on the response to CAPs in vivo will be directly tested by using knockout mice deficient in TNF receptors.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL068073-04
Application #
6985362
Study Section
Alcohol and Toxicology Subcommittee 4 (ALTX)
Program Officer
Croxton, Thomas
Project Start
2002-12-15
Project End
2007-11-30
Budget Start
2005-12-01
Budget End
2007-11-30
Support Year
4
Fiscal Year
2006
Total Cost
$316,386
Indirect Cost
Name
Harvard University
Department
Public Health & Prev Medicine
Type
Schools of Public Health
DUNS #
149617367
City
Boston
State
MA
Country
United States
Zip Code
02115
Rhoden, Claudia R; Wellenius, Gregory A; Ghelfi, Elisa et al. (2005) PM-induced cardiac oxidative stress and dysfunction are mediated by autonomic stimulation. Biochim Biophys Acta 1725:305-13
Yin, Lei; Stearns, Rebecca; Gonzalez-Flecha, Beatriz (2005) Lysosomal and mitochondrial pathways in H2O2-induced apoptosis of alveolar type II cells. J Cell Biochem 94:433-45
Radisavljevic, Ziv Manasija; Gonzalez-Flecha, Beatriz (2004) TOR kinase and Ran are downstream from PI3K/Akt in H2O2-induced mitosis. J Cell Biochem 91:1293-300
Carvalho, Helotonio; Evelson, Pablo; Sigaud, Samuel et al. (2004) Mitogen-activated protein kinases modulate H(2)O(2)-induced apoptosis in primary rat alveolar epithelial cells. J Cell Biochem 92:502-13
Rhoden, Claudia Ramos; Lawrence, Joy; Godleski, John J et al. (2004) N-acetylcysteine prevents lung inflammation after short-term inhalation exposure to concentrated ambient particles. Toxicol Sci 79:296-303
Gonzalez-Flecha, Beatriz (2004) Oxidant mechanisms in response to ambient air particles. Mol Aspects Med 25:169-82