Human intraepithelial mast cell differentiation and effector function are directed by TGF-β signaling
Tahereh Derakhshan, … , Joshua A. Boyce, Daniel F. Dwyer
Tahereh Derakhshan, … , Joshua A. Boyce, Daniel F. Dwyer
Published January 2, 2025
Citation Information: J Clin Invest. 2025;135(1):e174981. https://doi.org/10.1172/JCI174981.
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Research Article Immunology

Human intraepithelial mast cell differentiation and effector function are directed by TGF-β signaling

Abstract

Mast cells (MCs) expressing a distinctive protease phenotype (MCTs) selectively expand within the epithelium of human mucosal tissues during type 2 (T2) inflammation. While MCTs are phenotypically distinct from subepithelial MCs (MCTCs), signals driving human MCT differentiation and this subset’s contribution to inflammation remain unexplored. Here, we have identified TGF-β as a key driver of the MCT transcriptome in nasal polyps. We found that short-term TGF-β signaling alters MC cell surface receptor expression and partially recapitulated the in vivo MCT transcriptome, while TGF-β signaling during MC differentiation upregulated a larger number of MCT-associated transcripts. TGF-β inhibited the hallmark MCTC proteases chymase and cathepsin G at both the transcript and protein level, allowing selective in vitro differentiation of MCTs for functional study. We identified discrete differences in effector phenotype between in vitro–derived MCTs and MCTCs, with MCTs exhibiting enhanced proinflammatory lipid mediator generation and a distinct cytokine, chemokine, and growth factor production profile in response to both innate and adaptive stimuli, recapitulating functional features of their tissue-associated counterpart MC subsets. Thus, our findings support a role for TGF-β in promoting human MCT differentiation and identified a discrete contribution of this cell type to T2 inflammation.

Authors

Tahereh Derakhshan, Eleanor Hollers, Alex Perniss, Tessa Ryan, Alanna McGill, Jonathan Hacker, Regan W. Bergmark, Neil Bhattacharyya, Stella E. Lee, Alice Z. Maxfield, Rachel E. Roditi, Lora Bankova, Kathleen M. Buchheit, Tanya M. Laidlaw, Joshua A. Boyce, Daniel F. Dwyer

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Figure 3

TGF-β signaling directs the MCT protease phenotype during early development.

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TGF-β signaling directs the MCT protease phenotype during early developm...
(A) Differentially expressed genes encoding granule components in vivo (left), with violin plots for select proteases (center), and in vitro gene expression for PB-MC stimulated with TGF-β1 for 24 hours, 6 days, or differentiated in TGF-β1 (right). Columns indicate donor-averaged cluster expression (scRNA-Seq) or log2FoldChange versus untreated for each donor (bulk); scale bars denote z score (scRNA-Seq) or log2FoldChange (bulk), FDR < 0.05, log2FoldChange > 0.5 for scRNA-Seq and FDR < 0.05 for bulk (DESeq2). (B) Chymase expression and quantification in PB-MCs treated with (red) or without (blue) TGF-β1 for 6 days versus isotype control (gray). n = 6 individual donors (t test). (C–E) Expression and quantification of (C) chymase, (D) CTSG, and (E) CPA3 in PB-MCs differentiated with (purple) or without (blue) TGF-β1 versus isotype control (gray). n = 7–8 individual donors. **P < 0.01; ***P < 0.001; ****P < 0.0001 (t test). (F) One-week CPA3 and tryptase β2 release in PB-MCT versus PB-MCTC supernatants. n = 6 and 5 individual donors, respectively. *P < 0.05; **P < 0.01 (Mann-Whitney). (G) Chymase expression and quantification for PB-MCs differentiated in TGF-β1 and subsequently cultured with (purple) or without (orange) TGF-β1 for 2 weeks. n = 8 individual donors. ***P < 0.001 (t test). (H) Chymase expression and quantification for PB-MCT cocultured with EpCs for 2 weeks supplemented with SCF (100 ng/mL), IL-6 (50 ng/mL), and the indicated concentration of LY2109761. n = 8. *Padj < 0.05, **Padj < 0.01 (ANOVA) (I) Gating strategy to isolate nasal polyp MCTs and MCTCs. (J) Chymase expression and quantification for primary nasal polyp MCTs (top) or MCTCs (bottom) maintained in culture media with (red) or without (blue) TGF-β1 for 2 weeks. n = 6–7 for nasal polyp MCs. **P < 0.01 (t test). Box-and-whisker plots show median, interquartile range, and minimum/maximum values observed.