Comparative cytokine profile of human skin mast cells from two compartments—strong resemblance with monocytes at baseline but induction of IL-5 by IL-4 priming

Abstract

Although known as heterogenous, mast cells (MC) are believed to induce allergic inflammation, partially by secretion of T helper cell type 2 (Th2) cytokines. We show here that MC purified from two human skin compartments produce cytokines that are primarily associated with inflammation and innate immunity [interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha)]. Although these are detectable even without stimulation, immunoglobulin (Ig)E receptor cross-linking is able to enhance only TNF-alpha production, but phorbol 12-myristate 13-acetate additionally promotes IL-1beta and IL-8. With the exception of TNF-alpha, the presence of serum has a positive impact on cytokine production. Although IL-13 transcripts (but not those for IL-4 and -5) are produced by skin MC, all Th2 cytokines remain undetectable in the supernatants or lysates of MC from foreskin and breast skin by all treatments. Therefore, rather than sharing similarity with Th2 cells, the cytokine profile of skin MC at baseline resembles that of monocytes. Of note, MC precultured in the presence of IL-4 [alone or plus stem cell factor (SCF)] before anti-IgE stimulation, acquired the ability to produce IL-5, and IL-1beta was concomitantly suppressed. Additionally, strong up-regulation of IL-6 by SCF was observed, which was inhibited by IL-4. In summary, we present a detailed analysis of the cytokine array of human skin MC immediately upon isolation; demonstrate that MC from different skin compartments, although producing the same pattern of cytokines, display quantitative differences in several aspects; and provide further evidence that MC possess a proinflammatory capacity, which can, however, be altered by microenvironmental stimuli, substantiating the marked plasticity of the cells.

Long-Term Cultured Human Skin Mast Cells Are Suitable for Pharmacological Studies of Anti-Allergic Drugs Due to High Responsiveness to FcεRI Cross-Linking

“…This is a huge increment as compared to the much lower (and donor-dependent) release observed in skMCs upon purification. 10,13) In the long-term culture model, histamine release triggered by Fc"RI crosslinking reaches the same level as obtained with the calcium ionophore A23187, a well-known non-immunological MC secretagog (Fig. 2B).…”

“…Having established a technique to purify MCs to homogeneity from human skin, we have observed that IL-4 prolongs the survival of skin-derived MCs (skMCs). 8,10) It is unknown, however, whether IL-4 can promote skMC proliferation, and whether IL-4 treated skMCs increase in responsiveness towards Fc"RI aggregation, as found for several types of MCs. 6,11) The expression level and function of Fc"RI in skMCs from different human subjects are highly variable, and on average only about 15-25% of histamine is released upon Fc"RI cross-linking in freshly purified skMCs.…”

“…6,11) The expression level and function of Fc"RI in skMCs from different human subjects are highly variable, and on average only about 15-25% of histamine is released upon Fc"RI cross-linking in freshly purified skMCs. 10,12,13) To be suitable for pharmacological testing of anti-allergic drugs, MCs should display vigorous Fc"RI mediated responses. It would likewise be advantageous to have MCs available that are tissuederived, non-transformed, and of human origin, but which can be expanded in culture to overcome the limitations in cell numbers pertinent to human MC research.…”

IL-4-Induced Priming of Human Intestinal Mast Cells for Enhanced Survival and Th2 Cytokine Generation Is Reversible and Associated with Increased Activity of ERK1/2 and c-Fos

“…During the last years IL-4 has been recognized as an important regulator of human mast cells derived from intestine, lung, skin, or cord blood (5)(6)(7)(8)(9)(10)(11). In synergy with SCF, IL-4 enhances proliferation, mediator release, and Th2 cytokine generation.…”

Skin mast cells develop non‐synchronized changes in typical lineage characteristics upon culture

“…Mast cells were isolated from human breast skin (13)(14)(15) and cultured (in SCF + IL-4) for up to 16 weeks; at defined times, cells were analysed for proliferation (BrdU incorporation), gene expression (quantitative RT-PCR), protein expression (flow cytometry), protease activity, histamine content and stimulation by FceRI-cross-linking. All experimental procedures are detailed in the Supporting Information.…”