Transforming growth factor-beta1 mediates coexpression of the integrin subunit alphaE and the chymase mouse mast cell protease-1 during the early differentiation of bone marrow-derived mucosal mast cell homologues.
BACKGROUND
Mucosal mast cells (MMC) play a central role in gut hypersensitivities and inflammation. They are morphologically, biochemically and functionally distinct from their connective tissue counterparts. Massive hyperplasia of MMC occurs 7-10 days after intestinal infection with nematodes but it has never been possible to replicate this phenomenon in vitro.


OBJECTIVE
(1) To determine whether mouse bone marrow-derived mast cells (mBMMC) grown in the presence of transforming growth factor (TGF)-beta1 could develop over the same time frame (7-10 days) as MMC in parasitized mice. (2) To compare the early expression of surface receptors (integrins alphaE and beta7, c-kit and FcepsilonR) with that of the MMC-specific granule chymase mouse mast cell protease-1 (mMCP-1).


METHODS
Mouse bone marrow cells were cultured in the presence of IL-9, IL-3 and Stem Cell Factor (SCF) with or without TGF-beta1. mBMMC were quantified after toluidine blue or Leishmans' staining. Expression of MMC-specific mouse mast cell proteases was analysed by ELISA, immunohistochemistry and RT-PCR. Surface antigen expression was characterized by flow cytometry and confocal microscopy.


RESULTS
TGF-beta1 promotes the development of abundant MMC-like mBMMC from bone marrow progenitor cells with kinetics, which closely parallel that seen in vivo. mRNA transcripts encoding mMCP-1 and -2 are readily detectable by day 4 ex vivo in cultures grown in the presence of TGF-beta1. Between 30 and 40% and 75-90% of the cells in these cultures on days 4 and 7, respectively, have typical mast cell morphology, are c-kit+, FcepsilonR+, integrin alphaEbeta7+, and express and secrete abundant mMCP-1. The integrin alphaE subunit is coexpressed with mMCP-1.


CONCLUSIONS
The kinetics of mMCP-1+/alphaE+ mBMMC development, regulated by TGF-beta1, are consistent with that seen in vivo in the parasitized intestine. The normally down-regulatory functions of TGF-beta1 in haematopoiesis are superseded in this culture system by its ability to promote the early expression of alphaE and mMCP-1.
Wright
S H
SH
Department of Veterinary Clinical Studies, Wellcome Trust Centre For Research in Comparative Respiratory Medicine, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, Scotland, UK.
Brown
J
J
Knight
P A
PA
Thornton
E M
EM
Kilshaw
P J
PJ
Miller
H R P
HR
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D053818:Chymases; D039001:Integrin alpha Chains; D007377:Interleukin-3 / Q000494:pharmacology; D008297:Male; D008407:Mast Cells / Q000166:cytology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009092:Mucous Membrane / Q000166:cytology; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D016707:Tissue Fixation; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
D015703:Antigens, CD; D039001:Integrin alpha Chains; D007377:Interleukin-3; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C091367:alpha E integrins; D012697:Serine Endopeptidases; D053818:Chymases; C509230:Mcpt1 protein, mouse