Dermal fibroblasts respond to IL-4 and IL-13 and promote T cell recruitment in atopic dermatitis - PubMed (original) (raw)

. 2026 Jan 22;136(5):e196108.

doi: 10.1172/JCI196108. eCollection 2026 Mar 2.

Michael Shia, Yoshiyuki Nakamura, Fengwu Li, Hung Chan, Teruaki Nakatsuji, Kellen J Cavagnero, Jared Simmons, Henry Li, Aaroh Anand Joshi, Marta Palomo-Irigoyen, Richard L Gallo

Dermal fibroblasts respond to IL-4 and IL-13 and promote T cell recruitment in atopic dermatitis

Tomofumi Numata et al. J Clin Invest. 2026.

Abstract

Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by a type 2 immune response that is not fully understood. Single-cell RNA-seq of human AD skin and murine models of type 2 inflammation identified transcriptionally distinct fibroblast clusters, revealing IL-4Rα-dependent populations of immune-acting fibroblasts (IAFs). These unbiased findings prompted further investigation into the role of dermal fibroblasts during allergic inflammation. These studies demonstrated that, in an inflammatory environment including TNF-α, IL-1β, and IL-17A, the cytokines IL-4 and IL-13 stimulated both mouse and human fibroblasts to produce multiple chemokines, including CCL8, which activated CCR3 to attract T cells. In the skin, fibroblasts were the primary source of many of these chemokines, and targeted deletion of IL-4Rα in mouse fibroblasts reduced T cell infiltration in a mouse model of AD. Additionally, pharmacologic inhibition of CCR3, the receptor shared by many chemokines produced by fibroblasts, decreased T cell infiltration and skin inflammation in mouse models of AD. These findings demonstrate that dermal fibroblasts are more than passive structural cells; they actively participate in the type 2 immune response and contribute to AD by producing chemokines that increase inflammation. Targeting the functions of IAFs could offer an alternative therapeutic approach for AD.

Keywords: Adaptive immunity; Allergy; Cytokines; Dermatology; Immunology.

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Conflict of interest statement

Conflict of interest: RLG is a co-founder of, a scientific advisor and consultant to, and an equity holder in MatriSys Biosciences.

Figures

Figure 1

Figure 1. Transcriptional analysis of skin in AD shows increased chemokine gene expression by fibroblasts.

(A) Bar plot for proportion of each cell type identified in HC (n = 8), NL (n = 5), and LS (n = 4) samples and dot plots showing chemokine expression. (B) Intercellular communication analysis between cell types in HC, NL, and LS samples using CellChat.

Figure 2

Figure 2. IL-4Rα–dependent dermal fibroblasts express inflammatory chemokines in a mouse model of AD.

(A) Schematic of murine models of AD following topical application of MC + SA. (B) Uniform manifold approximation and projection (UMAP) plot of dermal fibroblast clusters from the back skin of mice in the following groups: control mice (Ctrl), mice treated with SA alone, mice treated with MC + SA, and IL-4Rα–/– mice treated with MC + SA. Dotted circles with each color contain the major cell population in each condition. (C) Frequency of each fibroblast cluster in control, SA, MC + SA, and MC + SA + IL-4Rα–/– samples. (D) Marker genes associated with specific fibroblast clusters. (E) Volcano plot of gene expression comparing IL-4Rα–dependent fibroblast clusters and control fibroblast clusters. (F) Gene enrichment analysis for genes upregulated in the IL-4Rα+ clusters compared with the control. (G) Comparison of chemokine expression profiles in human and mouse dermal fibroblasts in AD skin. avg.exp., average expression; pct.exp, percent expression.

Figure 3

Figure 3. Fibroblasts express multiple chemokines in response to IL-4/13.

(A) Schematic of the assessment of the response of 3T3-L1 fibroblasts to inflammatory cytokines. (B) PCA of the normalized bulk RNA-seq data from fibroblasts 24 hours after culturing under control conditions, with addition of IL-4 (50 ng/mL) and IL-13 (50 ng/mL) (IL-4/13), with the addition of a mixture of inflammatory cytokines TNF-α (20 ng/mL), IL-17A (50 ng/mL), and IL-1β (0.5 ng/mL) (Inf), or with IL-4/13 + Inf. (C) Heatmap illustrating changes in selected gene expression, scaled by row. (D) Gene enrichment analysis for 3T3-L1 fibroblasts treated with IL-4/13 + Inf and Inf alone. (E) Venn diagram showing the overlap of genes induced in cultured fibroblasts and mouse dermal fibroblasts. Shown is the expression of genes induced in cultured fibroblasts following the addition of Inf or IL-4/13 + Inf compared with control culture conditions, and fibroblast gene expression in mice determined by scRNA-seq of mouse skin exposed to SA alone or MC + SA compared with control mouse skin. Numbers indicate the numbers and percentages of upregulated genes with significant differences. The red dashed area highlights the 28 genes commonly upregulated across all 4 conditions. (F) List of 28 genes upregulated in fibroblasts in culture or in mice following exposure to type 2 cytokines. (G) qRT-PCR analysis of Ccl8, Ccl11, and Ccl17 mRNA expression in 3T3-L1 fibroblasts treated with Inf and IL-4/13 as in B (n = 3). (H) Measurement of CCL8 protein concentration in 3T3-L1 fibroblast supernatants by ELISA 72 hours after treatment with Inf or IL-4/13 as in B (n = 3). (I) Heatmap of protein expression measured by LEGENDPLEX in culture supernatants of the human fibroblast cell line HPAd. Statistical significance was determined by 1-way ANOVA followed by Tukey’s multiple-comparison test (G and H) (n = 3). Experiments in G–I are representative of 2–3 independent experiments. Data are presented as the mean ± SD.

Figure 4

Figure 4. Fibroblasts recruit T cells through the production of multiple chemokines.

(A) Schematic of the migration assay assessing the chemotactic activity of culture supernatant from fibroblasts. (B) Number of mouse bone marrow cells migrated toward the lower chamber containing fibroblast cultured supernatant. (C) Number of CD3e+ T cells from mouse splenocytes that migrated toward the lower chamber containing fibroblast cultured supernatant. (D) Comparison of the number of CD4+ T cells from the splenocyte migration assay. (E) Comparison of CD8a+ T cell numbers from the migration assay. (F) Comparison of CD3e+ T cell numbers in culture supernatants of fibroblasts after the indicated chemokine siRNA treatments. (G) Comparison of CD3e+T cell numbers after pretreatment with the indicated CCR antagonists in migration assays toward fibroblast culture supernatants. (H) Percentage of CD3e+ T cell staining for CCR3 before and after cell permeabilization. Statistical significance was determined by 1-way ANOVA followed by Tukey’s multiple-comparison test (B–G) or unpaired, 2-tailed Student’s t test (H) (n = 3). Experiments in B–H are representative of 2–3 independent experiments. Data are presented as the mean ± SD.

Figure 5

Figure 5. CCR3 antagonist reduces T cell numbers in skin and AD-related cytokine expression.

(A) Schematic of mouse model of AD treated with CCR3 antagonist (iCCR3, SB-328437, 20 μg/g body weight, administered i.p. every other day). (B) Representative images of dorsal skin from mice treated as in A, with and without iCCR3. (C) Disease score for mice treated as in A, with and without iCCR3. (D) Immunofluorescence images of CD3+ T cells (red) and nuclei (DAPI, blue) in dorsal skin from mice treated as in A, with and without iCCR3. Scale bars: 300 μm. (E) Flow cytometric quantification of CD3e+, CD4+, and CD8a+ T cells in dorsal skin from mice treated as in A, with and without iCCR3. (F) qRT-PCR analysis of Il4, Il13, Il17a, and Cxcl1 mRNA expression in dorsal skin from mice treated as in A, with and without iCCR3. (G) Flow cytometric quantification of neutrophils in dorsal skin from mice treated as in A, with and without iCCR3. (H) Ratio of CCR3+ cells of CD45+CD3e+ cells in dorsal skin from mice treated as in A, with and without iCCR3. (I) Immunofluorescence images of CD3+ T cells (red) and nuclei (DAPI, blue) in dorsal skin from _Pdgfra_ΔIl4ra mice treated as in A. Scale bars: 300 μm. (J) Flow cytometric quantification of CD3e+, CD4+, and CD8a+ T cells in dorsal skin from _Pdgfra_ΔIl4ra and control mice treated in the MC + SA model. Statistical significance was determined by unpaired, 2-tailed Student’s t test (C and E–H) or 1-way ANOVA followed by Tukey’s multiple-comparison test (J) (n = 3–10). Results are representative of 2–3 independent experiments. Data are presented as the mean ± SD.

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