Lung dopaminergic nerves facilitate the establishment of T_H2 resident memory cells in early life.

Abstract

Allergic asthma develops from allergen exposure in early childhood and progresses into adulthood. The central mediator of progressive allergic asthma is allergen-specific, T_H2-resident memory cells (TRMs). Although the crosstalk between nerves and immune cells plays an established role in acute allergic inflammation, whether nerves facilitate the establishment of T_H2-TRMs in the immature lung following early life allergen exposure is unknown. The aim of this study was to identify nerve-derived signals that act in T_H2 effector cells to regulate the tissue residency in the immature lung. Following neonatal allergen exposure, allergen-specific T_H2-TRMs were tracked temporally and spatially in relationship to developing sympathetic nerves in the lung. Functional mediators of dopamine signaling in the establishment of T_H2-TRMs were identified by in vitro bulk RNA-sequencing of dopamine-treated T_H2 cells followed by in vivo assessment of candidate genes using adoptive transfer of T_H2 cells with viral gene knockdown. This study found that sympathetic nerves produce dopamine and reside in proximity to T_H2 effector cells during the contraction phase following neonatal allergen exposure. Dopamine signals via DRD4 on T_H2 cells to elevate IL2RA and epigenetically facilitate type 2 cytokine expression. Blockade of dopamine-DRD4 signaling following neonatal allergen exposure impairs lung residence of T_H2 cells and ameliorates anamnestic inflammation in adults. These results demonstrate that maturing sympathetic nerves enable a dopamine-enriched lung environment in early life that promotes the establishment of allergen-specific T_H2-TRMs. The dopamine-DRD4 axis may provide a therapeutic target to modify allergic asthma progression from childhood to adulthood.