Lung resident Treg suppression of Th2 resident memory T cells in allergic asthma

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PROJECT SUMMARY Defining how FoxP3+ regulatory T cells (Tregs) limit amnestic responses to common allergens has the potential to provide new and effective therapies for asthma and other atopic diseases. Recent work has demonstrated that T helper type 2 (Th2) tissue-resident memory T cells (Trm) persist around the airways following allergic sensitization where they become rapidly activated and drive the asthma phenotype upon allergen re-exposure. The immunoregulatory mechanisms that limit the proinflammatory functions of Th2-Trm at mucosal sites are less clear. The objective of this proposal is to define the factors influencing allergen- specific resident (r) Treg maintenance in the lungs and their suppression of Th2-Trm following re-exposure to inhaled allergen. Our central hypothesis is that allergen-specific rTregs are positioned in a unique niche in the lung that enables potent suppression of allergic inflammation. Mechanistically, we hypothesize that rTregs co- localize with Th2-Trm based upon the CXCR6 and CCR8 chemokine systems. This proposal will explore these questions using novel experimental systems to define the function of rTregs in a mouse model of allergic asthma, including polyclonal adoptive transfer of house dust mite (HDM)-specific cells, parabiosis, single cell RNA sequencing analysis of HDM-specific T cells, and CRISPR-Cas9 gene editing. With Aim 1, we will build upon preliminary data to define the role of allergen-specific rTregs in suppressing lung Th2-Trm. We will characterize the localization, persistence, suppressive potency, and transcriptional profile of the Tregs that persist in the lung following allergen clearance. In Aim 2, we will determine the role of the CXCR6 and CCR8 chemokine systems in rTreg positioning and function. To identify additional factors important for the rTreg tissue residency program and provide additional training in genome editing and systems biology, we will perform an in vivo CRISPR-Cas9 screen on HDM-specific TCR transgenic cells isolated from the HDM memory lung. Dr. Nelson will perform the work in this K08 proposal, sponsored by Boston Children’s Hospital, at the Center for Immunology and Inflammatory diseases (CIID) at Massachusetts General Hospital (MGH) under the mentorship of Dr. Andrew Luster. Dr. Nelson has developed a career development plan consisting of coursework in advanced microscopy, bioinformatics, and translational research, along with mentored hands-on training in cutting-edge research methods to explore his research aims. The goal of this K08 award is to provide Dr. Nelson with the necessary skills and knowledge to become an independent, NIH-funded investigator with expertise in human disease models of atopic diseases and immunoregulation in non-lymphoid tissues.