Airway Injury Caused by MAA Adducts

点击翻译按钮获取中文摘要

DESCRIPTION (provided by applicant): Our overall interest is chronic inflammatory lung disease mechanisms in the context of combined alcohol use and cigarette smoking. Some studies report that up to 30% of smokers are heavy alcohol users. The airways of smokers who drink alcohol are more susceptible to bacterial infection and colonization, suggesting a compromise in the protective mucociliary apparatus. We hypothesize that prolonged exposure to the unique combination of cigarette smoking and ethanol consumption results in the impairment of the mucociliary transport apparatus. Large concentrations of malondialdehyde and acetaldehyde are found in the lungs of smoking alcoholics. Accumulation of lung aldehydes results in formation of hybrid aldehyde adducted proteins that produce pro-inflammatory effects parallel to liver necrosis and fibrosis. One such airway protein adduct is the malondialdehyde-acetaldehyde (MAA) adduct. The major mechanism of protein adduct binding to cells is via membrane scavenger receptors. We will explore the relationship between MAA adducts, alcohol consumption, and cigarette smoking with the following specific aims: 1) Determine if co-exposure to the combination of cigarette smoke and alcohol results in unique alterations to the mucociliary transport apparatus. 2) Determine if co-exposure to smoke and alcohol results in the formation of MAA adducts. 3) Identify the scavenger receptor that binds MAA-adducted protein to airway epithelium. 4) Determine the mechanism of action for MAA adduct-mediated cilia slowing. With these aims, we will establish an association between alcohol consumption, cigarette smoking and cilia dysfunction as mediated by MAA adduct formation. While the etiology of chronic inflammatory lung diseases is largely unknown and likely multi-faceted, the study of MAA adduct formation is an innovative approach to the pathologic interaction between cigarette smoke and alcohol. PUBLIC HEALTH SIGNIFICANCE: This study greatly impacts public health. It has long been clinically known that chronic lung disease and lung infections are much more severe in alcoholics. Nearly all alcoholics smoke cigarettes. Our studies seek to define the mechanisms that injure proper lung clearance and health under conditions of combined smoke and alcohol consumption. Understanding the mechanisms of such injury will define the subsequent treatment modalities to restoring normative lung mucociliary clearance function and directly address disease prevention in the approximately 20 million US alcoholics.