Key Points
Notch signaling enhances SMAD-dependent expression of mucosal mast cell markers.
Notch signaling regulates epigenetic modification of mucosal mast cell marker genes.
Notch signaling promotes the nuclear localization of SMADs 3 and 4 in mast cells.
Visual Abstract
Abstract
Rodent mast cells are classified into two major subsets, mucosal mast cells (MMCs) and connective tissue mast cells. MMCs arise from mast cell progenitors that are mobilized from the bone marrow to mucosal tissues in response to allergic inflammation or helminth infection. TGF-β is known as an inducer of MMC differentiation in mucosal tissues, but we have previously found that Notch receptor–mediated signaling also leads to the differentiation. Here, we examined the relationship between Notch and TGF-β signaling in MMC differentiation using mouse bone marrow-derived mast cells (BMMCs). We found that the coexistence of Notch and TGF-β signaling markedly upregulates the expression of MMC markers, mouse mast cell protease (mMCP)-1, mMCP-2, and αE integrin/CD103, more than Notch or TGF-β signaling alone, and that their signals act interdependently to induce these marker expressions. Notch and TGF-β–mediated transcription of MMC marker genes were both dependent on the TGF-β signaling transducer SMAD4. In addition, we also found that Notch signaling markedly upregulated mMCP-1 and mMCP-2 expression levels through epigenetic deregulation of the promoter regions of these genes, but did not affect the promoter of the CD103-encoding gene. Moreover, forced expression of the constitutively active Notch2 intracellular domain in BMMCs showed that Notch signaling promotes the nuclear localization of SMADs 3 and 4 and causes SMAD4-dependent gene transcription. These findings indicate that Notch and TGF-β signaling play interdependent roles in inducing the differentiation and maturation of MMCs. These roles may contribute to the rapid expansion of the number of MMCs during allergic mucosal inflammation.
Footnotes
This work was supported by Japan Society for the Promotion of Science Grant JP18K08416 (to N.N.).
The online version of this article contains supplemental material.
Abbreviations used in this article
- ALK
- activin receptor–like kinase
- BMMC
- bone marrow-derived mast cell
- ChIP
- chromatin immunoprecipitation
- CHO
- Chinese hamster ovary
- CTMC
- connective tissue mast cell
- DAPT
- N-[(3,5-difluorophenyl)acetyl]-L-alanyl-2-phenylglycine-1,1-dimethylethyl ester
- DLL1
- Delta-like 1
- H3K27ac
- acetylation of lysine residue 27 on histone H3
- H3K4me3
- trimethylation of lysine residue 4 on histone H3
- MMC
- mucosal mast cell
- mMCP
- mouse mast cell protease
- N2ICD
- Notch2 intracellular domain
- PMC
- peritoneal cell-derived mast cell
- SCF
- stem cell factor
- siRNA
- small interfering RNA
- TGF-βRII
- TGF-β receptor II
- Received February 5, 2021.
- Accepted October 17, 2021.
- Copyright © 2021 by The American Association of Immunologists, Inc.
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