PAC1 constrains type 2 inflammation through promotion of CGRP signaling in ILC2s
Yuan Jin, … , Yan Jin, Yuxin Yin
Yuan Jin, … , Yan Jin, Yuxin Yin
Published September 17, 2024
Citation Information: J Clin Invest. 2024;134(21):e180109. https://doi.org/10.1172/JCI180109.
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Research Article Immunology

PAC1 constrains type 2 inflammation through promotion of CGRP signaling in ILC2s

Abstract

Dysfunction of group 2 innate lymphoid cells (ILC2s) plays an important role in the development of type 2 inflammation–related diseases such as asthma and pulmonary fibrosis. Notably, neural signals are increasingly recognized as pivotal regulators of ILC2s. However, how ILC2s intrinsically modulate their responsiveness to these neural signals is still largely unknown. Here, using single-cell RNA-Seq, we found that the immune-regulatory molecule phosphatase of activated cells 1 (PAC1) selectively promoted the signaling of the neuropeptide calcitonin gene–related peptide (CGRP) in ILC2s in a cell-intrinsic manner. Genetic ablation of PAC1 in ILC2s substantially impaired the inhibitory effect of CGRP on proliferation and IL-13 secretion. PAC1 deficiency significantly exacerbated allergic airway inflammation induced by Alternaria alternata or papain in mice. Moreover, in human circulating ILC2s, the expression level of PAC1 was also significantly negatively correlated with the number of ILC2s and their expression level of IL13. Mechanistically, PAC1 was necessary for ensuring the expression of CGRP response genes by influencing chromatin accessibility. In summary, our study demonstrated that PAC1 is an important regulator of ILC2 responses, and we propose that PAC1 is a potential target for therapeutic interventions in type 2 inflammation–related diseases.

Authors

Yuan Jin, Bowen Liu, Qiuyu Li, Xiangyan Meng, Xiaowei Tang, Yan Jin, Yuxin Yin

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Figure 6

PAC1 promotes the expression of CGRP-response genes in ILC2s by influencing chromatin accessibility.

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PAC1 promotes the expression of CGRP-response genes in ILC2s by influenc...
(A) Expression levels (transcripts per million [TPM]) of Calcrl and Ramp1 in Pac1+/+ and Pac1–/– ILC2s under 4 different conditions of stimulation. Two replicates were analyzed per condition. (B) cAMP concentrations (nM) in cell lysates of Pac1+/+ and Pac1–/– ILC2s after 20 minutes of treatment under the conditions shown, as determined by ELISA (mean ± SEM). Three replicates were analyzed per condition. Statistical significance was assessed using a 2-way ANOVA followed by Holm-Šidák multiple-comparison test. (C) Proportion of ATAC-Seq peaks shared by Pac1+/+ and Pac1–/– ILC2s and the ATAC-Seq peaks unique to Pac1+/+ or Pac1–/– ILC2s, respectively, after 4 hours of treatment with NMU or NMU plus CGRP. (D) Distribution of ATAC-Seq peaks across the genome in Pac1+/+ and Pac1–/– ILC2s after 4 hours of treatment with NMU or NMU plus CGRP. (E) Distribution of ATAC-Seq signal around the TSS in Pac1+/+ and Pac1–/– ILC2s after 4 hours of treatment with NMU or NMU plus CGRP. (F) MA plots of merged ATAC-Seq peaks (localized in promoter and exon regions) in Pac1+/+ and Pac1–/– ILC2s after 4 hours of treatment with NMU plus CGRP. The top 5% of peaks (P < 0.05) for Pac1+/+ or Pac1–/– ILC2s are highlighted. Representative genes are shown, with the number of peaks in parentheses. (G) Chromatin accessibility for the Calca and Lgals3 loci in Pac1+/+ and Pac1–/– ILC2s after 4 hours of treatment with NMU or NMU plus CGRP. (H) KEGG pathways enriched by genes containing ATAC-Seq peaks unique to Pac1+/+ ILC2s after 4 hours of treatment with NMU plus CGRP. (I) Transcription factor binding motifs significantly enriched (top 15, P < 0.05) in the promoter regions and exon regions of Pac1+/+ and Pac1–/– ILC2s.