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

Area of Science:

• Immunology
• Cell Biology
• Allergy Research

Background:

• Mast cells (MCs) are crucial immune cells involved in allergic responses.
• Epithelial MCs (MCTs) differ phenotypically from subepithelial MCs (MCTCs) during type 2 (T2) inflammation.
• Signals regulating MCT differentiation and their role in T2 inflammation are largely unknown.

Purpose of the Study:

• To identify key signaling pathways driving human MCT differentiation.
• To investigate the functional contribution of MCTs to T2 inflammation.

Main Methods:

• Analysis of MC transcriptomes in nasal polyps.
• In vitro differentiation of MCs with TGF-β.
• Assessment of protease expression (chymase, cathepsin G).
• Evaluation of lipid mediator generation, cytokine, chemokine, and growth factor profiles.

Main Results:

• TGF-β was identified as a critical driver of the MCT transcriptome.
• TGF-β signaling modulated MC surface receptors and upregulated MCT-associated transcripts.
• TGF-β inhibited MCTC-specific proteases, enabling selective in vitro MCT differentiation.
• In vitro-derived MCTs showed enhanced pro-inflammatory mediator generation and distinct cytokine profiles compared to MCTCs.

Conclusions:

• TGF-β plays a significant role in promoting human MCT differentiation in T2 inflammation.
• MCTs possess a distinct effector phenotype contributing to T2 inflammation.
• Targeting TGF-β may offer therapeutic strategies for T2 inflammatory diseases.