Z Gastroenterol 2016; 54(12): 1343-1404
DOI: 10.1055/s-0036-1597353
1. Fibrogenesis
Georg Thieme Verlag KG Stuttgart · New York

Differentiation and effects of TGF-β1 and IL-3 signaling on primary murine endoglin deficient mast cells

M Neß
1   RWTH University Hospital Aachen, Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, Aachen, Germany
,
SK Meurer
1   RWTH University Hospital Aachen, Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, Aachen, Germany
,
JM Bangen
3   RWTH University Hospital Aachen, Department of Internal Medicine III, Aachen, Germany
,
M Huber
2   RWTH University Hospital Aachen, Institute of Biochemistry and Molecular Immunology, Aachen, Germany
,
C Liedtke
3   RWTH University Hospital Aachen, Department of Internal Medicine III, Aachen, Germany
,
R Weiskirchen
1   RWTH University Hospital Aachen, Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, Aachen, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
19 December 2016 (online)

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Background: Mast cells (MCs) are components of the innate immune system and are recruited to the inflamed and fibrotic liver [1]. Mast cell effects are in part based on the secretion of mitogenic and pro-fibrotic cytokines (e.g. TGF-β1) leading to activation and proliferation of fibroblasts [2]. Nevertheless, MCs themselves are targets of TGF-β1 and do express the accessory TGF-β receptor endoglin with yet unknown function in MCs [3].

Material and Methods: Endoglin deficient mast cells were generated by crossing mast cell specific Cre-expressing mice [4] with mice carrying floxed Endoglin alleles [5]. Primary MCs were isolated and expanded (peritoneal mast cells; PMC) or differentiated (bone marrow derived mast cells; BMMC) and analyzed by flow cytometry, cell counting and Western blot analysis [6].

Results: FACS analysis revealed that wildtype and Endoglin deficient PMC and BMMC achieved full maturity as demonstrated by detection of the surface markers c-kit and FcεR1α. However, PMC expansion from MC progenitors deficient in Endoglin was delayed. TGF-β1 reduced proliferation in the presence or absence of IL-3 without marked differences between the genotypes, whereas the amount of dead (apoptotic) cells in the presence of TGF-β1 is reduced in BMMC that lack Endoglin. Finally, we found that Endoglin affects the secretion of tryptase and granzyme B (gzmB) in the process of degranulation.

Conclusions: These results imply a function of endoglin in PMC differentiation and MC apoptosis. During degranulation, Endoglin affects the secretion of gzmB and tryptase from its cytoplasmic granules. This activity plays a critical role in the process of fibrosis.

References:

[1] Jones H et al. Inhibition of mast cell-secreted histamine decreases biliary proliferation and fibrosis in primary sclerosing cholangitis Mdr2(-/-) mice. Hepatology 2016. doi: 10.1002/hep.28704 [Epub ahead of print].

[2] Evans RA et al. TGF-β1-mediated fibroblast-myofibroblast terminal differentiation-the role of Smad proteins. Exp Cell Res 2003;282:90 – 100.

[3] Gebhardt T et al. Growth, phenotype, and function of human intestinal mast cells are tightly regulated by transforming growth factor β1. Gut 2005;54:928 – 34.

[4] Scholten J et al. Mast cell-specific Cre/loxP-mediated recombination in vivo. Transgenic Res 2008;17:307 – 15.

[5] Allinson KR et al. Generation of a floxed allele of the mouse endoglin gene. Genesis 2007;45:391 – 95:

[6] Meurer SK et al. Isolation of mature (peritoneum-derived) mast cells and immature (bone marrow-derived) mast cell precursors from mice. PLoS ONE 2016;11(6):e0158104.