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

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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