Examining Mechanisms of Synergy between Asthma Exacerbations and RV Infection

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PROJECT SUMMARY/ABSTRACT Dr. Kennedy is an Allergist/Immunologist at the University of Arkansas for Medical Sciences Departments of Pediatrics and Internal Medicine and a young investigator at Arkansas Children's Hospital Research Institute. A three-pronged mission to perform cutting-edge research, provide outstanding clinical care, and pursue educational excellence summarizes his overarching academic career objectives. His training and experience have enabled him to develop the skills and insight necessary to provide high-quality care to patients with asthma and allergic disorders, as well as providing a foundation for human subjects research. The primary objective for this mentored career development award proposal is to further Dr. Kennedy's knowledge and abilities in basic and translational investigation. This objective will specifically enable him to achieve my long-term research goals, including: 1) understanding the immune responses accounting for synergy between asthma exacerbations and infection with RV, 2) developing biomarkers of asthma disease severity and exacerbation following RV infection, and 3) translating this research into clinically relevant prevention and intervention strategies for patients with asthma. Asthma is prevalent in ~12% of the US population, and RV is recognized as the most important virus producing the common cold syndrome worldwide. Unlike patients without asthma who generally develop upper respiratory symptoms during colds, asthmatics with an RV infection may exhibit lower respiratory symptoms (e.g., cough, wheeze, shortness of breath). In fact, RV is associated with 60% to 80% of asthma exacerbations in children requiring treatment in the emergency department9-11. Despite such strong relationships, a significant knowledge gap exists with regards to the mechanisms whereby RV exacerbates asthma symptoms. Recent developments in cytokine biology have increasingly emphasized the importance of respiratory epithelial- derived cytokines in creating the milieu that promotes the evolution of allergic immune responses. The overall goal of this proposal is to understand the association between RV infection and the epithelial immune responses that bridge the allergic response to infection in asthmatics. We hypothesize that RV infection modulates epithelial cytokine expression [Interleukin (IL)-25 and thymic stromal lymphopoietin (TSLP)] in asthmatics with bias towards an allergic inflammatory response, and this underlies infection- mediated increases airway hyper-responsiveness (AHR). To address this hypothesis, we have a unique approach that brings together an in vivo study of epithelial-derived cytokines from subjects with asthma exacerbations, primary epithelial cell cultures, and a novel precision cut lung slice (PCLS) explant system allowing comparison of RV infections in asthmatic and non-asthmatic tissues. Using a cross-sectional design in a pediatric emergency department, we will compare cytokine signatures within nasal washes of asthmatics with RV-induced exacerbations and controls with cold symptoms and compare these levels with asthma symptoms. In ex vivo approaches, we will study mechanisms driving the production of IL-25 and TSLP by Toll-like receptor (TLR)-3 and Retinoic Acid Inducible Gene-I (RIG-I)-like receptors (RLR), both important in recognition of RV within epithelial cells. Finally, we will use the human airways PCLS to evaluate the effects of IL-25 and TSLP on AHR to carbachol and compare these responses between tissue derived from donors with and without asthma. By evaluating mechanisms of synergy that bridge the role of epithelial-derived cytokines to RV infection and asthma exacerbations, we will elucidate cytokine signatures and delineate pathways involved that will provide insight into the inflammatory environment produced by RV leading to exacerbations of asthma. Further, the studies within this proposal provide a firm foundation for research independence, allowing progression through further investigation of cellular targets (e.g., innate lymphoid type 2 cells (ILC2), mast cells) for these cytokines in RV-induced asthma exacerbations. To accomplish his research and academic goals, Dr. Kennedy has assembled a multi-tiered mentoring group with a wide breadth of experience. Interactions with his primary scientific co-mentors (Drs. Richard Kurten, Usha Ponnappan, and Reynold Panettieri) and his Scientific Advisory Committee (SAC) will enhance his understanding of the basic mechanisms of RV immunopathogenesis, develop research design skills, and expand his knowledge of advanced statistical techniques. Interactions with Dr. Stacie Jones, Chief of Pediatric Allergy and Immunology and primary career development mentor, will serve to improve his translational research acumen and enhance career development opportunities. Further, a Departmental Clinician Scientist Mentoring Committee composed of successful researchers at his institution has been in place since the beginning of his faculty appointment. This multi-tiered mentoring system will provide scientific and career development guidance that will enable Dr. Kennedy to become an independent researcher and an experienced clinician scientist specializing in RV-induced exacerbations of asthma.