Janina Wyczółkowska

Murine mast cells exposed to mercuric chloride release granule-associated N-acetyl-β-D-hexosaminidase and secrete IL-4 and TNF-α

Abstract Background: Mast cells, by virtue of their location within the skin, respiratory tract, and gastrointestinal system, are considered as potential targets for environmental agents with immunotoxic effects. Mercuric chloride (HgCl 2 ), is a xenobiotic, which induces autoimmune glomerulonephritis and stimulates polyclonal IgE production. Objective: We sought to determine the ability of HgCl 2 to degranulate murine mast cells and promote cytokine secretion and whether this was an active biologic process. Methods: Bone marrow–derived murine mast cells were exposed to HgCl 2 , and the release of N-acetyl-β-D-hexosaminidase and secretion of IL-4 and TNF-α were measured. Results: HgCl 2 was found to directly activate murine mast cells to release the granule-associated enzyme N-acetyl-β-D-hexosaminidase and to secrete the proinflammatory cytokines IL-4 and TNF-α. Cytokine secretion occurred hours after exposure to HgCl 2 and required transcription and protein synthesis. The secretion of cytokines mediated by HgCl 2 was additive to that which followed FcϵRI-induced mast cell activation. The IL-4 secretion by mast cells occurred at concentrations of HgCl 2 (10 –6 mol/L to 10 –5 mol/L) comparable with those required to induce upregulation of IgE production in experimental animals. Conclusion: These findings demonstrate that HgCl 2 will directly activate mast cells, which is followed by degranulation and IL-4 and TNF-α synthesis and secretion. These findings are consistent with recognition of HgCl 2 as a biologically important environmentally derived immunotoxic agent for mast cells. (J Allergy Clin Immunol 1999;103:1108-14.)

Interleukin 6 and 8 Levels in Plasma and Fibroblast Cultures in Psoriasis

Fibroblasts have been implicated in psoriatic inflammatory processes. The aim of the study was to evaluate soluble interleukin 2 receptor (sIL-2R), interleukin 6 (IL-6), and interleukin 8 (IL-8) plasma levels in psoriatic patients and IL-6 and IL-8 levels in fibroblast culture supernatants. Cytokines levels in plasma and supernatants were measured by ELISA. Plasma sIL-2R, IL-6, and IL-8 levels were higher before the treatment in comparison to healthy controls (P < 0.001) and decreased after treatment. Fibroblasts from healthy controls, psoriatic lesional skin, and noninvolved psoriatic skin, when stimulated with tumor necrosis factor alpha, released considerable amounts of IL-6 and IL-8. No significant difference between healthy controls and psoriatic fibroblasts was observed. Monitoring plasma sIL-2R levels could be employed as a reliable method of psoriasis activity. IL-8 and IL-6 plasma levels seem to reflect psoriasis activity, and treatment response, respectively. Fibroblasts are not a major source of increased IL-6 and IL-8 production in psoriasis.

The Inhibitory Effect of Nicotinamide on Asthma-Like Symptoms and Eosinophilia in Guinea Pigs, Anaphylactic Mast Cell Degranulation in Mice, and Histamine Release from Rat Isolated Peritoneal Mast Cells by Compound 48/80

The prior treatment of guinea pigs with nicotinamide diminished the symptoms of experimental bronchial asthma and the intensity of anaphylactic shock. Nicotinamide was also found to inhibit anaphylactic mast cell degranulation in mice and histamine release from rat-isolated peritoneal mast cells by compound 48/80. The role of nicotinamide in bronchial asthma is discussed.

c-Jun N-Terminal Kinase Is Involved in Mercuric Ions-Mediated Interleukin-4 Secretion in Mast Cells

Background: Interleukin (IL)-4 plays a prominent role in immune response. Mercuric compounds upregulate IL-4 expression in animal tissues, and this upregulation plays a role in mercuric-mediated immunomodulation. Mercuric ions-mediated IL-4 expression was observed in vitro in T lymphocytes and mast cells. In the present study, we investigated molecular mechanisms responsible for this effect of mercuric ions in mast cells. Methods: C1.MC/C57.1 mouse mast cells were exposed in vitro to increasing concentrations of Hg2+ in the absence or presence of the specific c-Jun N-terminal kinase (JNK) inhibitor SP600125. The level of phosphorylated c-Jun in mast cells was determined by Western blotting, JNK activity assessed with in vitro kinase assay and the amount of secreted IL-4 determined by ELISA. Results: We observed that Hg2+ upregulated c-Jun phosphorylation on Ser 73 at concentrations which overlapped concentrations mediating IL-4 secretion. Phosphorylation of c-Jun in mast cells was associated with an increase in JNK activity. The specific JNK inhibitor SP600125 abolished both mercuric-induced c-Jun phosphorylation and IL-4 secretion in mast cells. Conclusions: These observations are consistent with the hypothesis that JNK is one of the signaling proteins mediating the effect of Hg2+ on IL-4 expression in mast cells and is engaged in environmentally mediated immunomodulation.

Inhibition by nicotinamide of a homologous PCA reaction and antigen-induced histamine release from isolated rat peritoneal mast cells

(1) The inhibition of Histamine release by nicotinamide has been known about for a long time but its mode of action as well as the mechanism involved has remained ill-understood despite numerous hypothesis [1, 2, 5]. (a) In mast cells isolated from the rat peritoneum we have shown that nicotinamide (40 mM) will reduce by 2/s rds the release of histamine produced by 0.4 ~g/ml of compound 48/80. The liberation by the peptone of Witte is also reduced. However, compared to the inhibition of release by cyanide of mercury its action is weak. (b) In the dog, in vivo, taken as its own control, a dose of 150 m s / k s nicotinamide will reduce, in certain cases, the release of histamine produced by the injection of 100 ms /ks of the peptone of Witte. (2) Under other experimental conditions, on the other hand, nicotinamide is capable of liberating histamine, particularly when high concentrations are used [3]. Indeed, when one measures the insutttation resistance and arterial pressure in the anaesthetized guinea-pig, intravenous injection of 200 to 400 ms /ks nicotinamide immediately produces a violent and transient increase in insufflation resistance associated with a parallel hypotension. Previous injection of 5 ms /ks mepyramine prevents these effects. Using the isolated, perfused guinea-pig lung we have obtained a release of histamine of 0.1 ~xg/g rain when perfusing 50 m M nicotinamide at a rate of 5 ml/min. Also it has been found that the addition of nicotinamide to a preparation of chopped guinea-pig lung will show a release of histamine proportional to the dose added. Released histamine was measured by automated fluorometric analysis, the quantity of histamine dihydrochloride released being of the order of 1 ~g/g lung tissue in the presence of 125 m M nicotinamide per ml in contact with lung tissue. Values of 2 ~g for 250 m M and 3 ~xg for 374 m M were also obtained. Nicotinamide appears to inhibit nicotinamide-adenine-dinucleotidase and thus reduce histamine liberation. This mechanism must be clarified as well as the role of nicotinamide in the release of histamine.

Action of the human lymphokine histamine releasing factor on mouse peritoneal mast cells

Histamine releasing factor (HRF)--a human lymphokine--has been shown previously to release histamine from basophils in vitro. In this paper we show that HRF acted across the species barrier and released histamine from mouse peritoneal mast cells. This response was dose-dependent. Mast cells from both sensitized and non-sensitized mice were equally susceptible to the action of HRF. We observed synergistic action of HRF with specific allergen (ovalbumin) or HRF with anti-IgE antibody in releasing histamine from mast cells. Preincubation of mast cells with calcium ion chelating agent ethylenediaminetetraacetic acid (EDTA) or disodium cromoglycate induces only a small inhibition of histamine release caused by HRF. We conclude that histamine release from mouse peritoneal mast cells can serve as an in vitro test for the assay of human HRF.

Studies on histamine releasing factor (HRF) of human, murine and guinea-pig origin

There has been the lack of small animal models for the studies of histamine releasing factor (HRF). We have found that HRF producedin vitro by lymphocytes of asthmatic patients can act independently from the animal species and induces histamine secretion from mouse peritoneal mast cells. We also found, that spleen cells derived from normal as well as from sensitized mice and guinea-pigs are able to generate HRFin vitro, when cultured in suitable conditions. HRF of mouse and guinea-pig origin released histamine from homologous mast cellsin vitro and its activity was enhanced when spleen cell cultures were stimulated with specific antigens or non-specific mitogen.

Concanavalin A-induced activation of hamster mast cells: morphological changes and histamine secretion.

Peritoneal mast cells of Syrian hamsters release histamine to the action of concanavalin A (Con A) in dose-dependent fashion. The rate of release was very rapid in the first seconds of cell activation and completed in 60 s after the challenge. Morphological changes concomitant to the lectin treatment, followed by electron microscopy, show that early signs of exocytosis are seen after 10 s. The process starts in peripherally located granules which swell, have a decreased density and form pores by fusion of the cellular membrane and the perigranular membranes. Then it spreads toward the cell interior by fusion of granules and forming intracytoplasmic cavities. Some extruded granules are also observed. Preincubation of lectin with rat IgE or with rat serum induced an inhibition of its histamine releasing action. Immunization increased the Con A-induced histamine release in young but not in older hamsters. An IgE-mediated mechanism is suggested for the parallel ultrastructural changes and histamine release effects induced by Con A on the hamster mast cell.

Lectin-induced histamine release from various populations of hamster mast cells

Peritoneal, pleural and cheek pouch mast cells from Syrian hamsters were tested for their reactivity to the action of concanavalin A and the lectin fromCanavalia brasiliensis. Both lectins induced dose-dependent histamine release from hamster mast cells but the magnitude of release was different in the three mast cell populations (peritoneal>pleural>cheek pouch mast cells). The lectin fromCanavalia brasiliensis was a more potent histamine releaser than concanavalin A for the peritoneal and pleural mast cells. The responsiveness of these two populations of mast cells to the action of both lectins was dependent on the age of hamsters; in young animals up to six months old it increased with their age, whereas in older animals a slight decrease of the responsiveness was observed. Our results support the view that mast cells from different locations and from animals of different ages may show marked variations in their histamine releasing properties.

Inhibition by Nicotinamide of Antigen-Induced Histamine Release from Mouse Peritoneal Mast Cells

The in vitro antigen-induced histamine release from mouse peritoneal mast cells actively sensitized with IgE antibodies was inhibited by nicotinamide. The drug was either given in vivo to the sensitized mice (once daily 100 mg/kg) for 7 days before an in vitro experiment or incubated in vitro (in concentrations 1-40 mM) with sensitized mast cells before an antigen challenge. The possible action of nicotinamide on the mechanisms involved in the regulation of antigen-induced histamine release from mast cells is discussed.