Transcriptional Programming of Asthma Related Pathology in Respiratory Epithelia

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DESCRIPTION (provided by applicant): This new application seeks funding to identify and define a transcriptional network that determines Respiratory Epithelial Cell (REC) differentiation, goblet cell hyperplasia, and TH2-like pulmonary phenotypes related to the pathogenesis of asthma and other chronic pulmonary disorders. The application is based on novel data demonstrating the critical roles of a transcriptional network consisting of an Ets family member, SPDEF (SAM pointed domain ets-like factor) and FOXA2 in the regulation of goblet cell differentiation and TH2- like processes in the lung. Our preliminary data demonstrate that differentiation of epithelial cells in conducting airways, is mediated by an intrinsic transcriptional program regulated by FOXA2 and SPDEF that, in turn, drives goblet cell hyperplasia, eosinophilic chemokine, and TH2 cytokine expression from the respiratory epithelium. The application will utilize transgenic mouse models, bioinformatics, in vitro cultures of airway epithelial cells, and biochemistry to determine mechanisms controlling the intrinsic goblet cell program in the lung, and mechanisms by which the respiratory epithelium determines asthma related phenotypes in the mouse lung. Aim 1 will test the hypothesis that the transcription factor FOXA2 plays a critical role in conducting airway epithelial cell differentiation, regulating goblet cell hyperplasia and the expression of genes mediating TH2-like inflammation. Mechanisms by which FOXA2 and FOXA3 differentially regulate gene expression in the respiratory tract will be identified. Aim 2 will test the hypothesis that SPDEF, an ets-like factor, expressed in conducting airways, regulates goblet cell differentiation, in part, via FOXA2. Aim 3 will determine the role of Spdef gene deletion on respiratory epithelial cell differentiation, gene expression, and response to pulmonary allergen and IL-13 challenge, testing the hypothesis that Spdef is required for IL-13/allergen induced goblet cell differentiation. The applicant has had a long-standing interest in study of the cellular and molecular biology of the developing alveolar epithelium, and is recently applying these approaches to the study of conducting airway epithelial cell biology. This application is based on the identification of a novel transcriptional network driving goblet cell hyperplasia and TH2-like inflammation from the respiratory epithelium. These studies will provide insights into the pathogenesis of goblet cell hyperplasia and asthma, and will provide basis for the development of new strategies to diagnose and treat chronic respiratory diseases, including asthma, cystic fibrosis, and chronic obstructive pulmonary disease. PUBLIC HEALTH RELEVANCE: Goblet cell hyperplasia, inflammation, and tissue remodeling accompany common chronic respiratory disorders, including asthma, CF, and COPD. This application seeks to determine the role of a novel transcriptional network, mediated by FOXA2 and SPDEF, that regulates epithelial cell differentiation in the airways that, in turn, influences inflammation and innate host defense associated with these chronic pulmonary disorders. The work will identify mechanisms regulating airway epithelial homeostasis that will provide novel targets to diagnose and influence the pathogenesis of chronic pulmonary diseases affecting the airways.