Calcitonin gene related peptide negatively regulates alarmin-driven type 2 innate lymphoid cell responses

Neuroimmune interactions have emerged as critical modulators of allergic inflammation, and type 2 innate lymphoid cells (ILC2s) are an important cell type for mediating these interactions. Here, we show that ILC2s expressed both the neuropeptide CGRP (Calcitonin Gene-Related Peptide) and its receptor. CGRP potently inhibited alarmin-driven type 2 cytokine production and proliferation by lung ILC2s both in vitro and in vivo. CGRP induced marked changes in ILC2 expression programs in vivo and in vitro, attenuating alarmin-driven proliferative and effector responses. A distinct subset of ILCs scored highly for a CGRP-specific gene signature after in vivo alarmin stimulation, suggesting CGRP regulated this response. Finally, we observed increased ILC2 proliferation and type 2 cytokine production and exaggerated responses to alarmins in mice lacking the CGRP receptor. Together, these data indicate that endogenous CGRP is a critical negative regulator of ILC2 responses in vivo. Overall design: For in vitro bulk RNA-seq experiments, there are 32 samples total, representing 2 biological replicates, each split into 2 technical replicates, of 4 conditions at 2 time points. For in vivo scRNA-seq experiments, there are 8 samples total, representing 2 biological replicates of 4 conditions at 1 time point. For in vitro ATAC-seq experiments, there are 6 samples total, representing 3 replicates of 2 conditions at 1 time point.