Mechanisms of Responses to Diesel Exhaust and Stress

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DESCRIPTION (provided by applicant) The proposed career development and research plans will prepare the candidate to conduct independent research focusing on how the toxic effects of air pollutants may be modified in susceptible individuals, using animal models. Evidence from epidemiological studies indicates that individuals with pre-existing cardiovascular (CV) disease are at increased risk of CV effects from particulate matter air pollution (PM). The research plan will test the hypothesis that the CV effects of PM are mediated by systemic inflammatory responses to local injury and inflammation in the lungs, and that altered macrophage numbers and activity in lung and liver contribute to increased sensitivity of apolipoprotein E-deficient (ApoE-/-) mice to these effects. Moreover, toxic effects will be enhanced by co-exposure to stress. To test this hypothesis, the candidate will use freshly generated diesel exhaust (DE) as a model PM exposure. The first aim is to determine if ApoE-/- mice exhibit increased susceptibility to DE-induced pulmonary and systemic inflammation and prothrombotic activity. ApoE-/- and control mice will be exposed to DE (30-1000 mu/g/m3 PM) or control for 3-6 hours, with outcomes measured at 0-72 hours post-exposure. Markers of inflammation will be assessed in the lung, liver, blood, and blood vessels, including cell counts, cytokine expression, circulating acute phase proteins, and cell adhesion molecules. The second aim is to determine if increases in the sensitivity of ApoE-/- mice to DE are due to increased macrophage numbers and activity in the lung and liver. Dependence of DE-induced effects on macrophages will be tested by selectively depleting these cells using liposomes. The third aim is to determine if stress alters DE-induced inflammatory responses and prothrombotic activity. Inflammation and prothrombotic activity will be analyzed in ApoE-/- and control mice after exposure to DE with and without an acute stressor. Career development plans include mentorship and training in inhalation toxicology and psychoneuroimmunology through supervised research and structured educational activities. Laboratory techniques to be learned include animal exposures, surgery, cell culture, western blotting, ELISA, in situ hybridization, RT-PCR and histochemical procedures. The career development plan will enable the candidate to achieve his overall goal of conducting research that integrates animal studies with human exposure studies. The experimental studies will contribute to elucidating mechanisms underlying CV effects of PM.