Human skin–derived mast cells can proliferate while retaining their characteristic functional and protease phenotypes

Abstract

IntroductionMultipotential progenitor cells, capable of becoming mast cells, leave the bone marrow and enter the circulation, but they complete their differentiation into mature mast cells only after arriving in peripheral tissues such as lung, bowel, skin, and nasal and conjunctival mucosa. Mature human mast cells can be distinguished from other cell types by expression of high levels of surface Fc⑀RI and Kit, and of granule tryptase and heparin. Two types of human mast cells have been identified based on their composition of neutral proteases. 1-6 MC TC cells contain tryptase, chymase, mast cell carboxypeptidase, and cathepsin G in their secretory granules and are the predominant type of mast cells in normal skin and in intestinal submucosa. MC T cells also contain tryptase in their granules, but lack these other proteases, and are the predominant type of mast cell in normal alveolar wall and in small intestinal mucosa.In a number of human diseases such as asthma, 7,8 allergic rhinitis, 9,10 rheumatoid arthritis, [11][12][13] and vernal keratoconjunctivitis, 14 significant increases in mast cell density at the local affected sites have been described and mast cells were estimated to play a central role in the pathophysiology of the associated inflammation. The principal mechanisms involved in mast cell hyperplasia were thought to be either the recruitment of progenitor cells and their differentiation to mast cells or the migration of mast cells from other regions of the tissue. Proliferation has been considered less likely in part because cells were considered to be terminally differentiated and also because mitotic mast cells are rarely appreciated at these sites.The proliferative potential of most myelomonocytic multipotential hematopoietic cells diminishes as they differentiate. However, mature murine mast cells have been reported to proliferate both in vivo and in vitro. About 6% of mouse peritoneal mast cells proliferate after being injected into skin of W/W v mast cell-deficient mice. 15,16 Purified peritoneal mast cells 17,18 or dispersed skin mast cells, 19 when plated in methylcellulose containing pokeweed mitogen-stimulated spleen cell-conditioned medium, produced mast cell colonies. However, in humans, isolated tissue-derived mast cells have shown little capacity for proliferation. For example, dispersed newborn foreskin or adult skin mast cells placed into culture with lymphocyte-conditioned media and various cytokines showed bromodeoxyuridine incorporation in up to 15% mast cells. 20 The current study shows that a substantial portion of mast cells dispersed from adult human skin can proliferate under serum-free culture conditions with recombinant human stem cell factor (rhuSCF), while retaining expression of chymase and tryptase in secretory granules, Kit, and Fc⑀RI on their surface and the ability to degranulate in response to IgG anti-Fc⑀RI␣, compound 48/80 and substance P. Materials and methods Antibodies and reagentsBiotin-conjugated mouse IgG monoclonal antibody (mAb) antichymase, B7-biotin, ...

Is there a role for mast cells in psoriasis?

“…Prolonged subcutaneous injection of SCF for up to 14 days results in mast cell and melanocyte hyperplasia in the skin [26]. Mature mast cells isolated from human skin specimens can be cultured in serum-free medium in the presence of SCF, and these cells even proliferate and maintain their proteinase phenotype in such conditions [85] suggesting that a mature MC TC mast cell is capable of proliferation in response to SCF during a disease process. In a mouse model of skin inXammation, Kit expression is essential for mast cell accumulation which further supports the importance of SCF-Kit interaction [201].…”

“…The stem cell factor (SCF) (Kit ligand) is a well-known and essential factor for the growth, migration, activation and survival of human mast cells developed and cultured in vitro [93,123,133,134] or isolated from skin specimens [45,85]. SCF injected subcutaneously induces anaphylactic-like activation and degranulation of dermal mast cells in situ followed by inXammatory cell recruitment such as neutrophils, eosinophils and basophils [35].…”

Syk deficiency in human non-releaser lung mast cells

“…Skin derived mast cells, obtained as described (8) were examined in parallel with the lung mast cells as a positive control. Skin and lung mast cells were challenged with various concentrations of antiFcεRI mAb and examined for degranulation (β-hexosaminidase, Figure 1A) and cytokine (GMCSF, Figure 1B) release.…”

Human Skin Mast Cells Express Complement Factors C3 and C5

“…Human skin mast cells and lung mast cells were isolated as described previously (25,55). Fresh skin and lung were obtained from the Pathology Department of Virginia Commonwealth University (VCU) or Cooperative Human Tissue Network of the National Cancer Institute or National Disease Research Interchange as reviewed and approved by the VCU Institutional Review Board, and used as a source of mast cells.…”

“…SCF binds to CD117 (Kit) on the mast cell surface, preventing apoptosis and facilitating their activation (21)(22)(23)(24). Human skin mast cells, capable of proliferating when cultured in serum-free medium containing SCF, retain the functional and phenotypic characteristics from when they were freshly dispersed (25). Human mast cell b-tryptase can activate C3 and C5 to generate the corresponding anaphylatoxins (26), delineating a novel putative amplification loop for inflammation initiated by either mast cells or complement (26,27) and further linking the complement and mast cell pathways to one another in humans.…”