PROJECT SUMMARY/ABSTRACT This project investigates the contribution of the pulmonary sensory afferent nervous system to airway inflammation in asthma and its relationship to asthma endotypes. Asthma is a highly prevalent disease in children and adults with that causes diminished quality of life, work/school absence, increased healthcare utilization and associated costs, and in extreme cases, disability and even death. While all asthmatic patients fulfill the same diagnostic criteria of intermittent wheeze, cough, and chest tightness in the presence of airflow obstruction or bronchoprovocation testing with response to bronchodilating agents, it is now understood that asthma represents a heterogenous set of distinct pathological phenotypes of asthma that produce the same hallmark clinical syndrome (1). Using gene expression analysis from asthmatics and controls, the laboratory of my mentor, Dr. Prescott Woodruff, has described two important endotypes of asthma involving TH2-high or TH2-low genetic signatures. Given the variable response to available therapies for asthma between different asthmatic phenotypes, new insights into the pathogenesis of known phenotypes and elucidation of novel subphenotypes is of significant clinical importance. In recent years, a compelling body of work has emerged that establishes immunomodulatory connections between neuropeptides secreted from airway nerves and pulmonary neuroepithelial cells (PNECs) (2,3) and cells in the airway compartment, including epithelial cells, resident innate lymphoid cells (ILCs), and infiltrating immune cells, among others. Several neuropeptides, including Calcitonin Gene-Related Peptide (CGRP) and Vasoactive Intestinal Peptide (VIP), are implicated in development of allergic asthma in animal models. Using already-gathered epithelial biopsies and BAL fluid from asthmatic subjects and healthy controls, the experiments proposed in this application will investigate the presence and role of the neuropeptides CGRP and VIP in promoting and/or maintaining TH2 inflammation in the asthmatic airway via interactions with epithelial cells, PNECs, ILC2 cells, and other immune cells. My initial aim is to examine differences in nerve density, neuropeptide concentration in BALF, and neuropeptide receptor expression within known asthma TH2-high and TH2-low endotypes, with a goal of establishing specific neuropeptidergic phenotypes or sub-phenotypes in these patients. In my second aim, I will analyze whether neuropeptidergic phenotypes are correlated with important clinical and biological outcomes, including degree of airway obstruction, symptom burden, sputum and serum biomarker levels, and exacerbation history, controlling for TH2 status. I expect that our findings will establish novel neural/neuropeptide pathway-related phenotypes that may be amenable for precision-guided therapies aimed at neurogenic inflammation in asthma.