Neuropeptide CGRP limits ILC2 responses and constrains type 2 inflammation

Innate and adaptive lymphocytes work in concert to maintain tissue homeostasis and to mediate host defense at mucosal barriers. Herein, we used single cell analysis to show substantial diversity of gene expression in ILCs and T helper cells during a helminth infection in the lung. Notably, we found that the Calca gene, which is spliced to generate the neuropeptide CGRP, was selectively transcribed in ILC2s and Th2 cells in an activation dependent manner. The Calca locus acquired chromatin accessibility at the ILC2 precursor stage and is pre-programmed for rapid production of CGRP upon ILC2 activation. CGRP globally antagonized actions of neuromedin U (NMU) and the alarmin IL-33. However, CGRP selectively acted in concert with NMU and IL-33 to promote IL-5 expression, but not IL-13. The complex interplay among neuropeptides and alarmin fine-tunes type 2 immune responses and will undoubtedly become more relevant as therapeutic neuropeptide blockade advances in the clinic. Integrated analysis of transcriptome and epigenome data from ILCs and Th cells in steady or activated conditions