RESUMEN
The IL-1-related molecules, IL-1 and IL-18, can promote Th2 cytokine production by IgE/antigen-FcepsilonRI-stimulated mouse mast cells. Another IL-1-related molecule, IL-33, was identified recently as a ligand for T1/ST2. Although mouse mast cells constitutively express ST2, the effects of IL-33 on mast cell function are poorly understood. We found that IL-33, but not IL-1beta or IL-18, induced IL-13 and IL-6 production by mouse bone marrow-derived, cultured mast cells (BMCMCs) independently of IgE. In BMCMCs incubated with the potently cytokinergic SPE-7 IgE without specific antigen, IL-33, IL-1beta, and IL-18 each promoted IL-13 and IL-6 production, but the effects of IL-33 were more potent than those of IL-1beta or IL-18. IL-33 promoted cytokine production via a MyD88-dependent but Toll/IL-1R domain-containing adaptor-inducing IFN-beta-independent pathway. By contrast, IL-33 neither induced nor enhanced mast cell degranulation. At 200 ng/ml, IL-33 prolonged mast cell survival in the absence of IgE and impaired survival in the presence of SPE-7 IgE, whereas at 100 ng/ml, IL-33 had no effect on mast cell survival in the absence of IgE and reduced mast cell survival in the presence of IgE. These observations suggest potential roles for IL-33 in mast cell- and Th2 cytokine-associated immune responses and disorders.
Asunto(s)
Interleucina-13/biosíntesis , Interleucinas/farmacología , Mastocitos/efectos de los fármacos , Mastocitos/inmunología , Receptores de IgE/inmunología , Transducción de Señal/efectos de los fármacos , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Animales , Apoptosis/efectos de los fármacos , Células de la Médula Ósea/citología , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/enzimología , Células de la Médula Ósea/fisiología , Degranulación de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Inmunoglobulina E/inmunología , Subunidad alfa del Receptor de Interleucina-18/inmunología , Interleucina-33 , Mastocitos/enzimología , Mastocitos/fisiología , Ratones , Ratones Endogámicos C57BL , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Factor 88 de Diferenciación Mieloide/metabolismo , Fosforilación/efectos de los fármacos , Receptores Tipo I de Interleucina-1/inmunologíaRESUMEN
BACKGROUND: Mast cells, IgE, and TNF, which have been implicated in human atopic asthma, contribute significantly to the allergic airway inflammation induced by ovalbumin (OVA) challenge in mice sensitized with OVA without alum. However, it is not clear to what extent mast cells represent a significant source of TNF in this mouse model. OBJECTIVE: We investigated the importance of mast cell-derived TNF in a mast cell-dependent model of OVA-induced airway hyperreactivity (AHR) and allergic airway inflammation. METHODS: Features of this model of airway inflammation were analyzed in C57BL/6J-wild-type mice, mast cell-deficient C57BL/6J-Kit(W-sh)(/W-sh) mice, and C57BL/6J Kit(W-sh/W-sh) mice that had been systemically engrafted with bone marrow-derived cultured mast cells from C57BL/6J-wild-type or C57BL/6J-TNF(-/-) mice. RESULTS: Ovalbumin-induced AHR and airway inflammation were significantly reduced in mast cell-deficient Kit(W-sh/W-sh) mice versus wild-type mice. By contrast, Kit(W-sh/W-sh) mice that had been engrafted with wild-type but not with TNF(-/-) bone marrow-derived cultured mast cells exhibited responses very similar to those observed in wild-type mice. Mast cells and mast cell-derived TNF were not required for induction of OVA-specific memory T cells in the sensitization phase, but significantly enhanced lymphocyte recruitment and T(H)2 cytokine production in the challenge phase. CONCLUSION: Mast cell-derived TNF contributes significantly to the pathogenesis of mast cell-dependent and IgE-dependent, OVA-induced allergic inflammation and AHR in mice, perhaps in part by enhancing lymphocyte recruitment and T(H)2 cytokine production. CLINICAL IMPLICATIONS: Our findings in mice support the hypothesis that mast cell-derived TNF can promote allergic inflammation and AHR in asthma.
Asunto(s)
Asma/inmunología , Hiperreactividad Bronquial/inmunología , Citocinas/biosíntesis , Mastocitos/inmunología , Neumonía/inmunología , Células Th2/inmunología , Factor de Necrosis Tumoral alfa/fisiología , Animales , Modelos Animales de Enfermedad , Peroxidasa del Eosinófilo/metabolismo , Pulmón/enzimología , Pulmón/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ovalbúmina/inmunología , Peroxidasa/metabolismo , Neumonía/enzimología , Neumonía/patología , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
BACKGROUND: TNF is thought to contribute to airway hyperreactivity (AHR) and airway inflammation in asthma. However, studies with TNF-deficient or TNF receptor-deficient mice have not produced a clear picture of the role of TNF in the AHR associated with allergic inflammation in the mouse. OBJECTIVE: We used a genetic approach to investigate the contributions of TNF to antigen-induced AHR and airway inflammation in mice on the C57BL/6 background. METHODS: We analyzed features of airway allergic inflammation, including antigen-induced AHR, in C57BL/6 wild-type and TNF(-/-) mice, using 2 different methods for sensitizing the mice to ovalbumin (OVA). RESULTS: In mice sensitized to OVA administered with the adjuvant aluminum hydroxide (alum), which develop IgE-independent and mast cell-independent allergic inflammation and AHR, we found no significant differences in OVA-induced AHR in C57BL/6-TNF(-/-) versus wild-type mice. By contrast, in mice sensitized to OVA without alum, which develop allergic inflammation that is significantly mast cell-dependent, C57BL/6-TNF(-/-) mice exhibited significant reductions versus wild-type mice in OVA-induced AHR to methacholine; numbers of lymphocytes, neutrophils, and eosinophils in bronchoalveolar lavage fluid; levels of myeloperoxidase, eosinophil peroxidase, and the cytokines IL-4, IL-5, and IL-17 in lung tissue; and histologic evidence of pulmonary inflammation. CONCLUSION: In pulmonary allergic inflammation induced in mice immunized with OVA without alum, TNF significantly contributes to several features of the response, including antigen-induced inflammation and AHR. CLINICAL IMPLICATIONS: Our findings in mice support the hypothesis that TNF can promote the allergic inflammation and AHR associated with asthma.
Asunto(s)
Asma/genética , Hiperreactividad Bronquial/genética , Hipersensibilidad Respiratoria/genética , Factor de Necrosis Tumoral alfa/fisiología , Animales , Asma/patología , Hiperreactividad Bronquial/patología , Bronquitis/genética , Bronquitis/inmunología , Bronquitis/patología , Citocinas/análisis , Modelos Animales de Enfermedad , Inmunoglobulina E/inmunología , Pulmón/inmunología , Pulmón/patología , Mastocitos/inmunología , Ratones , Ratones Mutantes , Ovalbúmina/inmunología , Receptores Tipo I de Factores de Necrosis Tumoral/genética , Receptores Tipo I de Factores de Necrosis Tumoral/fisiología , Receptores Tipo II del Factor de Necrosis Tumoral/genética , Receptores Tipo II del Factor de Necrosis Tumoral/fisiología , Hipersensibilidad Respiratoria/patología , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
The granules of mast cells and other inflammatory cells are known to be rich in zinc (Zn), a potent caspase inhibitor. The functions of granular Zn, its mechanism of uptake, and its relationship to caspase activation in apoptosis are unclear. The granules of a variety of mast cell types fluoresced intensely with the Zn-specific fluorophore Zinquin, and fluorescence was quenched by functional depletion of Zn using a membrane-permeable Zn chelator N, N, N', N'-tetrakis (2-pyridyl-methyl)ethylenediamine (TPEN). Zn levels were also depleted by various mast cell activators, including IgE/anti-IgE, and Zn was rapidly replenished during subsequent culture, suggesting an active uptake mechanism. In support of the latter, mast cells contained high levels of the vesicular Zn transporter ZnT(4), especially in the more apical granules. Immunofluorescence and immunogold labeling studies revealed significant pools of procaspase-3 and -4 in mast cell granules and their release during degranulation. Functional depletion of Zn by chelation with TPEN, but not by degranulation, resulted in greatly increased susceptibility of mast cells to toxin-induced caspase activation, as detected using a fluorogenic substrate assay. Release of caspases during degranulation was accompanied by a decreased susceptibility to toxins. Zn depletion by chelation, but not by degranulation, also resulted in nuclear translocation of the antiapoptotic, proinflammatory transcription factor NF-kappaB. These findings implicate a role for ZnT(4) in mast cell Zn homeostasis and suggest that granule pools of Zn may be distinct from those regulating activation of procaspase-3 and NF-kappaB.