Sonic Hedgehog signaling limits atopic dermatitis via Gli2-driven immune regulation
Eleftheria Papaioannou, … , Ryan F. L. O’Shaughnessy, Tessa Crompton
Eleftheria Papaioannou, … , Ryan F. L. O’Shaughnessy, Tessa Crompton
Published August 1, 2019; First published July 2, 2019
Citation Information: J Clin Invest. 2019;129(8):3153-3170. https://doi.org/10.1172/JCI125170.
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Research Article Immunology Inflammation

Sonic Hedgehog signaling limits atopic dermatitis via Gli2-driven immune regulation

Abstract

Hedgehog (Hh) proteins regulate development and tissue homeostasis, but their role in atopic dermatitis (AD) remains unknown. We found that on induction of mouse AD, Sonic Hedgehog (Shh) expression in skin and Hh pathway action in skin T cells were increased. Shh signaling reduced AD pathology and the levels of Shh expression determined disease severity. Hh-mediated transcription in skin T cells in AD-induced mice increased Treg populations and their suppressive function through increased active transforming growth factor–β (TGF-β) in Treg signaling to skin T effector populations to reduce disease progression and pathology. RNA sequencing of skin CD4+ T cells from AD-induced mice demonstrated that Hh signaling increased expression of immunoregulatory genes and reduced expression of inflammatory and chemokine genes. Addition of recombinant Shh to cultures of naive human CD4+ T cells in iTreg culture conditions increased FOXP3 expression. Our findings establish an important role for Shh upregulation in preventing AD, by increased Gli-driven, Treg cell–mediated immune suppression, paving the way for a potential new therapeutic strategy.

Authors

Eleftheria Papaioannou, Diana C. Yánez, Susan Ross, Ching-In Lau, Anisha Solanki, Mira Manilal Chawda, Alex Virasami, Ismael Ranz, Masahiro Ono, Ryan F. L. O’Shaughnessy, Tessa Crompton

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Figure 6

Transcriptional mechanisms of Gli2-mediated antiinflammatory action in skin CD4+ T cells.

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Transcriptional mechanisms of Gli2-mediated antiinflammatory action in s...
(A–C and F) RNA-seq; data sets from 2 independent experimental groups of FACS-sorted pooled skin CD4+ T cells from Oxa-treated WT (n = 3), Gli2ΔN2 (n = 3), and Gli2ΔC2 (n = 3) mice. (A) PCA shows PC2 for WT (blue) and Gli2ΔC2 (green) mice; PC1 for WT (blue) and Gli2ΔN2 (red) mice. (B) Intersection of 3000 genes that contributed most to PC2 and 1500 most significant DEGs between WT and Gli2ΔC2 mice. (C) Intersection of 3000 genes that contributed most to PC1 and 2500 most significant DEGs between WT and Gli2ΔN2 mice. (B and C) Heatmaps cluster intersection genes; green is lower expression; red is higher expression. (D) Representative contour plots show CD4 against CD8 (left); CD25 against Foxp3 (gated on CD4+) (right) from Oxa-treated skin from WT and Gli2ΔN2 (top) mice; and WT and Gli2ΔC2 (bottom) mice. Plots show percentage of Tregs (of skin CD4+ T cells) in WT (black) or Gli2ΔN2 or Gli2ΔC2 (red). (E) Percentage of CD25+Foxp3+, gated on skin CD4+ from Oxa-treated littermates. Left: WT (black), Gli3+/– (red). Right: WT (black), Shh+/– (red). (F) Expression of immune regulation genes from Gli2ΔN2 (blue) and Gli2ΔC2 (red) RNA-seq. (G) Il10 and Tgfb1 expression (QRT-PCR) in Oxa-treated ear homogenates from littermates: WT (black) and Gli2ΔN2 (red) (left); WT (black) and Gli2ΔC2 (red) (right); 2 independent experiments. (H) Two independent experiments. Top: WT-CD4+CD25– T cells cocultured with CD4+CD25+ cells from Oxa-treated Gli2ΔC2 and WT spleens and WT-CD4+CD25– proliferation (CFSE staining). Plot shows percentage of nonproliferating cells on addition of WT-Tregs (black) and Gli2ΔC2-Tregs (red). Bottom: WT-CD4+CD25– T cells cocultured (1:1) with CD4+CD25+ cells from Oxa-treated Gli2ΔN2 and WT spleens. Plot shows percentage of cells that underwent divisions (CFSE staining) for WT-Tregs (black) and Gli2ΔN2-Tregs (red). Representative histograms show cell divisions without Tregs (left) and divisions cocultured 1:1 (right) with WT-Tregs (red) and Gli2ΔC2-Tregs (blue). Plots show mean ± SEM; for D–E, G, and H (bottom) each symbol represents an individual animal; 2-tailed unpaired Student’s t test. *P < 0.05, ***P < 0.001.