Alcohol drives S-nitrosylation to impair airway mucociliary clearance

University Of Nebraska Medical Center, Omaha NE

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Abstract

? DESCRIPTION (provided by applicant): The broad focus of this project is to understand the effects of alcohol on the lung. The primary objective of this application is to determine the role f alcohol on mucociliary clearance (MCC). Specifically, we plan to examine the role of alcohol to stimulate S-nitrosylation of the serine/threonine phosphatase, protein phosphatase 1 (PP1), in airway cilia to contribute to impaired MCC and subsequent airway disease. Airway diseases are among the leading causes of morbidity and mortality worldwide with pneumonia contributing to a substantial number of these cases. Although numerous factors influence the outcome of pneumonia, alcohol abuse, which can impair clearance of pathogens and debris from the airway, is associated with an increase in complications and a higher mortality rate during the progression of pneumonia. Mucociliary clearance, which depends on the coordinated beating of cilia, can be stimulated to propel mucus from the airways. This stimulation is blunted with chronic exposure to alcohol. This phenomenon is known as alcohol-induced ciliary dysfunction (AICD). Factors such as nitric oxide (NO ?), cyclic nucleotides and phosphorylation, which are altered by alcohol exposure, are key in regulating cilia motility. In a search for additional factos that impact stimulation of cilia motility, we previously examined the role of dephosphorylation. We found that prolonged alcohol exposure activates PP1 to play a critical role in the mechanism of AICD. We have further demonstrated that inhibition of PP1 reverses AICD. Structure based studies indicate that PP1 contains an oxidant sensitive active site. Consistent with this, concomitant feeding of mice with alcohol and antioxidants prevents AICD produced by in vivo alcohol drinking in mice. Based on these studies, activation of PP1 by nitrosative signaling may contribute to impaired MCC and airway disease in individuals with alcohol use disorders. Therefore, based on evidence from the literature and our preliminary experiments, we hypothesize that in states of prolonged nitrosative stress, such as prolonged alcohol exposure, increased S-nitrosylation acts as a post-translational modification to signal activation of PP1. To investigate this hypothesis two specific aims are proposed. In Specific Aim 1, the link between S-nitrosylation and PP1 in causing cilia desensitization to stimuli will be investigated in isolate organelle, cell culture and tissue models of AICD. In Specific Aim 2, an in vivo alcohol drinking mouse model will be used to investigate the potential sites of interaction between S-nitrosylation and AICD. A comprehensive pre-doctoral training program is described with the goal of maturing and expanding the research skills of the applicant in order to become a successful physician-scientist. Specific objectives of the training plan including mastering and understanding the role of research techniques, learning to independently navigate research problems, developing collaborations and networking skills, disseminating scientific information and maintaining and expanding clinical skills to foster bench to bedside translational thinking.