GM-CSF Downregulates Expression of Tryptase, Fc Epsilon Rl and Histamine in HMC-1 Mast Cells

摘要

Fibroblast-derived growth factors like SCF are able to upregulate the expression of mast cell characteristics in human multilineage hematopoietic progenitor cells. Other factors, like GM-CSF, have been reported to inhibit this process, probably by the competitive recruitment of cells not belonging to the mast cell lineage. In this study, we investigated the influence of GM-CSF on immature mast cells of the HMC-1 cell line which already show low-level expression of mast cell tryptase, histamine and FcεRIα. Culture of HMC-1 cells with mast-cell-conditioning medium, containing fíbroblast supernatants, upregulated tryptase activity, histamine contents and expression of FcεRIα. However, addition of GM-CSF (10 ng/ml) markedly downregulated these mast cell markers, without affecting proliferation and viability of cells. Thus, GM-CSF may provide an inhibitory signal during mast cell differentiation and probably even downregulates mast cell characteristics in more differentiated c