RESUMO
BACKGROUND: Systemic Janus kinase inhibitors (JAKi) and dupilumab both have emerged as promising therapeutics for atopic dermatitis (AD). While dupilumab has a favorable safety profile, use of oral JAKi has been established in other diseases that carry potential comorbid susceptibilities that influence safety. OBJECTIVE: To provide real-world evidence of the safety of oral JAKi in AD patients. METHODS: The study used observational data from TriNetX (Cambridge, Massachusetts). Patients with AD treated with either oral JAKi (upadacitinib, abrocitinib, and baricitinib) or dupilumab were enrolled. The two treatment groups were propensity-score matched 1:1 based on demographics, comorbidities, and prior medications. Safety outcomes within two years after the initiation of medications were measured by hazard ratios with 95% confidence intervals. RESULTS: A total of 14,716 patients were included, with 942 patients treated with oral JAKi and 13,774 with dupilumab. The two treatment groups included 938 patients after matching. Treatment with oral JAKi was not associated with increased risks of mortality, malignancies, major adverse cardiovascular events, venous thromboembolism, renal events, or serious gastrointestinal events. However, patients receiving oral JAKi showed significantly higher risks of skin and subcutaneous tissue infection, herpes infection, acne, cytopenia, and hyperlipidemia, whereas the risk of ophthalmic complications was higher in those receiving dupilumab. CONCLUSION: This study found that oral JAKi did not exhibit concerning safety issues in treating patients with AD but increased the risk of infections and laboratory abnormalities. Long-term follow-up data are required to validate these findings.
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Scratching triggers skin flares in atopic dermatitis. We demonstrate that scratching of human skin and tape stripping of mouse skin cause neutrophil influx. In mice, this influx was largely dependent on the generation of leukotriene B4 (LTB4) by neutrophils and their expression of the LTB4 receptor BLT1. Allergic skin inflammation in response to epicutaneous (EC) application of ovalbumin to tape-stripped skin was severely impaired in Ltb4r1(-/-) mice and required expression of BLT1 on both T cells and non-T cells. Cotransfer of wild-type (WT) neutrophils, but not neutrophils deficient in BLT1 or the LTB4-synthesizing enzyme LTA4H, restored the ability of WT CD4(+) effector T cells to transfer allergic skin inflammation to Ltb4r1(-/-) recipients. Pharmacologic blockade of LTB4 synthesis inhibited allergic skin inflammation elicited by cutaneous antigen challenge in previously EC-sensitized mice. Our results demonstrate that a neutrophil-T cell axis reliant on LTB4-BLT1 interaction is required for allergic skin inflammation.
Assuntos
Dermatite/imunologia , Leucotrieno B4/imunologia , Infiltração de Neutrófilos , Neutrófilos/imunologia , Animais , Biópsia , Dermatite/patologia , Modelos Animais de Doenças , Humanos , Leucotrieno B4/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Receptores do Leucotrieno B4/deficiência , Receptores do Leucotrieno B4/imunologiaRESUMO
BACKGROUND: Patients with eosinophilic esophagitis have increased numbers of mucosal mast cells. Administration of the proton pump inhibitor omeprazole can reduce both esophageal mast cell and eosinophil numbers and attenuate type 2 inflammation in these subjects. OBJECTIVE: Given that maintenance of an acidic environment within granules is important for mast cell homeostasis, we sought to evaluate the effects of omeprazole on mast cell functions including development, IgE:FcεRI-mediated activation, and responses to food allergen. METHODS: Mast cell degranulation, cytokine secretion, and early signaling events in the FcεRI pathway, including protein kinase phosphorylation and Ca2+ flux, were measured after IgE crosslinking in murine bone marrow-derived mast cells and human cord blood-derived mast cells. The effects of omeprazole on these responses were investigated as was its impact on mast cell-dependent anaphylaxis and food allergy phenotypes in vivo. RESULTS: Murine and human mast cells treated with omeprazole exhibited diminished degranulation and release of cytokines and histamine in response to allergen. In murine mast cells, phosphorylation of protein kinases, ERK and SYK, was decreased. Differentiation of mast cells from bone marrow progenitors was also inhibited. IgE-mediated passive anaphylaxis was blunted in mice treated with omeprazole as was allergen-induced mast cell expansion and mast cell activation in the intestine in a model of food allergy. CONCLUSIONS: Our findings suggest that omeprazole targets pathways important for the differentiation and activation of murine mast cells and for the manifestations of food allergy and anaphylaxis.
Assuntos
Alérgenos/imunologia , Hipersensibilidade Alimentar/imunologia , Imunoglobulina E/imunologia , Mastócitos/efeitos dos fármacos , Mastócitos/imunologia , Omeprazol/farmacologia , Animais , Degranulação Celular , Células Cultivadas , Citocinas/metabolismo , Modelos Animais de Doenças , Hipersensibilidade Alimentar/tratamento farmacológico , Hipersensibilidade Alimentar/metabolismo , Hipersensibilidade Alimentar/patologia , Humanos , Mediadores da Inflamação/metabolismo , Mastócitos/metabolismo , Camundongos , Receptores de IgE/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: Atopic dermatitis (AD) is associated with epidermal barrier defects, dysbiosis, and skin injury caused by scratching. In particular, the barrier-defective epidermis in patients with AD with loss-of-function filaggrin mutations has increased IL-1α and IL-1ß levels, but the mechanisms by which IL-1α, IL-1ß, or both are induced and whether they contribute to the aberrant skin inflammation in patients with AD is unknown. OBJECTIVE: We sought to determine the mechanisms through which skin injury, dysbiosis, and increased epidermal IL-1α and IL-1ß levels contribute to development of skin inflammation in a mouse model of injury-induced skin inflammation in filaggrin-deficient mice without the matted mutation (ft/ft mice). METHODS: Skin injury of wild-type, ft/ft, and myeloid differentiation primary response gene-88-deficient ft/ft mice was performed, and ensuing skin inflammation was evaluated by using digital photography, histologic analysis, and flow cytometry. IL-1α and IL-1ß protein expression was measured by means of ELISA and visualized by using immunofluorescence and immunoelectron microscopy. Composition of the skin microbiome was determined by using 16S rDNA sequencing. RESULTS: Skin injury of ft/ft mice induced chronic skin inflammation involving dysbiosis-driven intracellular IL-1α release from keratinocytes. IL-1α was necessary and sufficient for skin inflammation in vivo and secreted from keratinocytes by various stimuli in vitro. Topical antibiotics or cohousing of ft/ft mice with unaffected wild-type mice to alter or intermix skin microbiota, respectively, resolved the skin inflammation and restored keratinocyte intracellular IL-1α localization. CONCLUSIONS: Taken together, skin injury, dysbiosis, and filaggrin deficiency triggered keratinocyte intracellular IL-1α release that was sufficient to drive chronic skin inflammation, which has implications for AD pathogenesis and potential therapeutic targets.
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Dermatite Atópica/metabolismo , Inflamação/metabolismo , Interleucina-1alfa/metabolismo , Proteínas de Filamentos Intermediários/deficiência , Queratinócitos/metabolismo , Animais , Dermatite Atópica/imunologia , Dermatite Atópica/microbiologia , Disbiose/imunologia , Disbiose/metabolismo , Proteínas Filagrinas , Inflamação/imunologia , Inflamação/microbiologia , Interleucina-1alfa/imunologia , Queratinócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos KnockoutRESUMO
OBJECTIVE: To summarize the literature on immunomodulatory effects of breast milk on sensitization and possible mechanisms of action. DATA SOURCES: Animal and human studies in PubMed that assessed breastfeeding or breast milk composition in food allergy. STUDY SELECTIONS: All recent studies and some older key publications focusing on this topic. RESULTS: Human milk composition is highly variable among mothers, which can affect the developing infant immune system. Human milk also affects the infant gut microbiome, which is associated with food allergy. High levels of human milk immune factors (IgA, cytokines, oligosaccharides) are associated with reduced risk of food allergy in the infant; it remains uncertain whether these are directly protective or biomarkers of transferred protection. Animal studies highlight potential mechanisms of protection provided by antigens, transforming growth factor ß, and immunocomplexes, yet their relevance is poorly understood in humans. The role of food antigens in human milk in initial sensitization or tolerance induction is unclear. CONCLUSION: The protection against allergy development provided by human milk may be attributable to the effect on the infant gut microbiome or direct effects on immune system. Studies evaluating the effect of breastfeeding and human milk composition on food allergy are needed.
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Hipersensibilidade Alimentar/prevenção & controle , Microbioma Gastrointestinal/fisiologia , Tolerância Imunológica/imunologia , Leite Humano/imunologia , Animais , Antígenos/imunologia , Aleitamento Materno , Hipersensibilidade Alimentar/imunologia , Humanos , Lactente , Recém-Nascido , Modelos AnimaisRESUMO
Mutations in filaggrin are associated with atopic dermatitis. Filaggrin-deficient flaky tail (Flgft/ft) mice develop spontaneous inflammatory skin lesion that wax and wane. We show that loss of MyD88 promotes the persistence of skin lesions in Flgft/ft mice and exaggerates their expression of the Th17-associated cytokines Il7a and Il22. The development and persistence of skin lesions in Flgft/ft mice was independent of the microbiota. MyD88-mediated signals are shown to be important for the accumulation of T regulatory cells (Tregs) in lesional skin of Flgft/ft mice. Adoptive transfer of WT Tregs dampened the severity of skin lesions in MyD88-/-/Flgft/ft mice. These results suggest that MyD88 signaling in Treg cells by endogenous ligands attenuates skin inflammation in filaggrin deficiency.
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Dermatite Atópica/imunologia , Proteínas de Filamentos Intermediários/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Pele/imunologia , Linfócitos T Reguladores/fisiologia , Células Th17/imunologia , Transferência Adotiva , Animais , Dermatite Atópica/genética , Modelos Animais de Doenças , Proteínas Filagrinas , Humanos , Interleucina-17/metabolismo , Interleucinas/metabolismo , Proteínas de Filamentos Intermediários/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Mutantes , Fator 88 de Diferenciação Mieloide/genética , Transdução de Sinais , Pele/patologia , Interleucina 22RESUMO
BACKGROUND: Eosinophilic esophagitis (EoE) is an allergic inflammatory disorder characterized by accumulation of eosinophils in the esophagus. EoE often coexists with atopic dermatitis, a chronic inflammatory skin disease. The impaired skin barrier in patients with atopic dermatitis has been suggested as an entry point for allergic sensitization that triggers development of EoE. OBJECTIVE: We sought to define the mechanisms whereby epicutaneous sensitization through a disrupted skin barrier induces development of EoE. METHODS: To elicit experimental EoE, mice were epicutaneously sensitized with ovalbumin (OVA), followed by intranasal OVA challenge. Levels of esophageal mRNA for TH2 cytokines and the IL-33 receptor Il1rl1 (St2) were measured by using quantitative PCR. Esophageal eosinophil accumulation was assessed by using flow cytometry and hematoxylin and eosin staining. In vivo basophil depletion was achieved with diphtheria toxin treatment of Mcpt8DTR mice, and animals were repopulated with bone marrow basophils. mRNA analysis of esophageal biopsy specimens from patients with EoE was used to validate our findings in human subjects. RESULTS: Epicutaneous sensitization and intranasal challenge of wild-type mice resulted in accumulation of eosinophils and upregulation of TH2 cytokines and St2 in the esophagus. Disruption of the IL-33-ST2 axis or depletion of basophils reduced these features. Expression of ST2 on basophils was required to accumulate in the esophagus and transfer experimental EoE. Expression of IL1RL1/ST2 mRNA was increased in esophageal biopsy specimens from patients with EoE. Topical OVA application on unstripped skin induced experimental EoE in filaggrin-deficient flaky tail (ft/ft) mice but not in wild-type control or ft/ft.St2-/- mice. CONCLUSION: Epicutaneous allergic sensitization promotes EoE, and this is critically mediated through the IL-33-ST2-basophil axis.
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Basófilos/imunologia , Dermatite Atópica/imunologia , Esofagite Eosinofílica/imunologia , Interleucina-33/imunologia , Adolescente , Alérgenos/imunologia , Animais , Criança , Pré-Escolar , Esôfago/imunologia , Feminino , Proteínas Filagrinas , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Ovalbumina/imunologia , RNA Mensageiro/metabolismo , Receptores Tipo I de Interleucina-1/genética , Receptores Tipo I de Interleucina-1/imunologiaRESUMO
BACKGROUND: Cutaneous exposure to food allergens predisposes to food allergy, which is commonly associated with atopic dermatitis (AD). Levels of the epithelial cytokine IL-33 are increased in skin lesions and serum of patients with AD. Mast cells (MCs) play a critical role in food-induced anaphylaxis and express the IL-33 receptor ST2. The role of IL-33 in patients with MC-dependent food anaphylaxis is unknown. OBJECTIVE: We sought to determine the role and mechanism of action of IL-33 in patients with food-induced anaphylaxis in a model of IgE-dependent food anaphylaxis elicited by oral challenge of epicutaneously sensitized mice. METHODS: Wild-type, ST2-deficient, and MC-deficient KitW-sh/W-sh mice were epicutaneously sensitized with ovalbumin (OVA) and then challenged orally with OVA. Body temperature was measured by means of telemetry, Il33 mRNA by means of quantitative PCR, and IL-33, OVA-specific IgE, and mouse mast cell protease 1 by means of ELISA. Bone marrow-derived mast cell (BMMC) degranulation was assessed by using flow cytometry. RESULTS: Il33 mRNA expression was upregulated in tape-stripped mouse skin and scratched human skin. Tape stripping caused local and systemic IL-33 release in mice. ST2 deficiency, as well as ST2 blockade before oral challenge, significantly reduced the severity of oral anaphylaxis without affecting the systemic TH2 response to the allergen. Oral anaphylaxis was abrogated in KitW-sh/W-sh mice and restored by means of reconstitution with wild-type but not ST2-deficient BMMCs. IL-33 significantly enhanced IgE-mediated degranulation of BMMCs in vitro. CONCLUSION: IL-33 is released after mechanical skin injury, enhances IgE-mediated MC degranulation, and promotes oral anaphylaxis after epicutaneous sensitization by targeting MCs. IL-33 neutralization might be useful in treating food-induced anaphylaxis in patients with AD.
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Anafilaxia/imunologia , Hipersensibilidade Alimentar/imunologia , Interleucina-33/imunologia , Mastócitos/imunologia , Administração Cutânea , Alérgenos/imunologia , Animais , Dermatite Atópica/imunologia , Feminino , Humanos , Imunoglobulina E/imunologia , Interleucina-33/genética , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Ovalbumina/imunologia , RNA Mensageiro/metabolismo , Pele/imunologiaRESUMO
BACKGROUND: Eczema vaccinatum is a life-threatening complication of smallpox vaccination in patients with atopic dermatitis (AD) characterized by dissemination of vaccinia virus (VV) in the skin and internal organs. Mutations in the filaggrin (FLG) gene, the most common genetic risk factor for AD, confer a greater risk for eczema herpeticum in patients with AD, suggesting that it impairs the response to cutaneous viral infections. OBJECTIVE: We sought to determine the effects of FLG deficiency on the response of mice to cutaneous VV inoculation. METHODS: VV was inoculated by means of scarification of unsensitized skin or skin topically sensitized with ovalbumin in FLG-deficient flaky tail (ft/ft) mice or wild-type (WT) control mice. The sizes of primary and satellite skin lesions were measured, and hematoxylin and eosin staining was performed. VV genome copy numbers and cytokine mRNA levels were measured by using quantitative PCR. RESULTS: VV inoculation in unsensitized skin of ft/ft mice, independent of the matted hair mutation, resulted in larger primary lesions, more abundant satellite lesions, heavier viral loads in internal organs, greater epidermal thickness, dermal cellular infiltration, and higher local Il17a, Il4, Il13, and Ifng mRNA levels than in WT control mice. VV inoculation at sites of topical ovalbumin application amplified all of these features in ft/ft mice but had no detectable effect in WT control mice. The number of satellite lesions and the viral loads in internal organs after cutaneous VV inoculation were significantly reduced in both unsensitized and topically sensitized ft/ftxIl17a(-/-) mice. CONCLUSION: FLG deficiency predisposes to eczema vaccinatum. This is mediated primarily through production of IL-17A.
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Dermatite Atópica/imunologia , Genoma Viral , Interleucina-17/imunologia , Proteínas de Filamentos Intermediários/imunologia , Erupção Variceliforme de Kaposi/imunologia , Vaccinia virus/imunologia , Animais , Dermatite Atópica/genética , Dermatite Atópica/patologia , Dermatite Atópica/virologia , Progressão da Doença , Feminino , Proteínas Filagrinas , Expressão Gênica , Humanos , Interferon gama/genética , Interferon gama/imunologia , Interleucina-13/genética , Interleucina-13/imunologia , Interleucina-17/deficiência , Interleucina-17/genética , Interleucina-4/genética , Interleucina-4/imunologia , Proteínas de Filamentos Intermediários/deficiência , Proteínas de Filamentos Intermediários/genética , Erupção Variceliforme de Kaposi/genética , Erupção Variceliforme de Kaposi/patologia , Erupção Variceliforme de Kaposi/virologia , Masculino , Camundongos , Camundongos Knockout , Ovalbumina/administração & dosagem , RNA Mensageiro/genética , RNA Mensageiro/imunologia , Pele/imunologia , Pele/patologia , Pele/virologia , Vaccinia virus/genéticaRESUMO
PURPOSE OF REVIEW: Eosinophilic esophagitis (EoE) is a chronic allergic disease triggered by food allergens with an increasing prevalence. This review highlights recent research advances in EoE with a focus on the literature of the past 18 months. RECENT FINDINGS: The incidence of EoE in the black population is higher than previously suggested. A novel locus spanning CAPN14 is associated with EoE. Diagnostic tests utilizing an analysis of EoE-specific transcriptome have been improved. Standardized EoE symptom score systems have been established. Treatment trials show the promise and limitations of allergen avoidance, antiinflammatory reagents, and anti-interleukin-13 antibodies. Insights into disease mechanisms highlight the role of invariant natural killer T cells and group 2 innate immune cells. Epithelial barrier protein desmoglein 1, bone morphogenetic protein antagonist follistatin, neurotrophic tyrosine kinase receptor type 1, and CAPN14 have been defined as new potential therapeutic targets in EoE as regulators of the inflammatory interleukin-13-axis. The role of IgG4 in the disease mechanisms has been suggested. SUMMARY: Genetic predisposition influenced by environmental factors increases EoE susceptibility. Research identifying the critical events leading to allergen sensitization and the esophagus-specific responses that drive EoE is evolving, and will lead to a better understanding of EoE and new therapeutic approaches for the disease.
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Calpaína/genética , Esofagite Eosinofílica/genética , Predisposição Genética para Doença/genética , Adolescente , Alérgenos/imunologia , Criança , Pré-Escolar , Esofagite Eosinofílica/epidemiologia , Esofagite Eosinofílica/fisiopatologia , Genótipo , Humanos , Incidência , Estados Unidos/epidemiologiaRESUMO
Atopic dermatitis (AD) skin lesions exhibit epidermal and dermal thickening, eosinophil infiltration, and increased levels of the cysteinyl leukotriene (cys-LT) leukotriene C(4) (LTC(4)). Epicutaneous sensitization with ovalbumin of WT mice but not ΔdblGATA mice, the latter of which lack eosinophils, caused skin thickening, collagen deposition, and increased mRNA expression of the cys-LT generating enzyme LTC(4) synthase (LTC(4)S). Skin thickening and collagen deposition were significantly reduced in ovalbumin-sensitized skin of LTC(4)S-deficient and type 2 cys-LT receptor (CysLT(2)R)-deficient mice but not type 1 cys-LT receptor (CysLT(1)R)-deficient mice. Adoptive transfer of bone marrow-derived eosinophils from WT but not LTC(4)S-deficient mice restored skin thickening and collagen deposition in epicutaneous-sensitized skin of ΔdblGATA recipients. LTC(4) stimulation caused increased collagen synthesis by human skin fibroblasts, which was blocked by CysLT(2)R antagonism but not CysLT(1)R antagonism. Furthermore, LTC(4) stimulated skin fibroblasts to secrete factors that elicit keratinocyte proliferation. These findings establish a role for eosinophil-derived cys-LTs and the CysLT(2)R in the hyperkeratosis and fibrosis of allergic skin inflammation. Strategies that block eosinophil infiltration, cys-LT production, or the CysLT(2)R might be useful in the treatment of AD.
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Dermatite Atópica/patologia , Eosinófilos/metabolismo , Leucotrieno C4/metabolismo , Receptores de Leucotrienos/metabolismo , Transdução de Sinais , Pele/imunologia , Pele/patologia , Transferência Adotiva , Animais , Proliferação de Células , Colágeno/metabolismo , Dermatite Atópica/complicações , Dermatite Atópica/imunologia , Derme/imunologia , Derme/patologia , Modelos Animais de Doenças , Eosinófilos/enzimologia , Fibrose , Fatores de Transcrição GATA/metabolismo , Glutationa Transferase/deficiência , Glutationa Transferase/metabolismo , Humanos , Imunização , Queratinócitos/imunologia , Queratinócitos/patologia , Camundongos , Ovalbumina/imunologia , Pele/enzimologiaRESUMO
Food allergy is a rapidly growing public health concern because of its increasing prevalence and life-threatening potential. Animal models of food allergy have emerged as a tool for identifying mechanisms involved in the development of sensitization to normally harmless food allergens, as well as delineating the critical immune components of the effector phase of allergic reactions to food. However, the role animal models might play in understanding human diseases remains contentious. This review summarizes how animal models have provided insights into the etiology of human food allergy, experimental corroboration for epidemiologic findings that might facilitate prevention strategies, and validation for the utility of new therapies for food allergy. Improved understanding of food allergy from the study of animal models together with human studies is likely to contribute to the development of novel strategies to prevent and treat food allergy.
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Modelos Animais de Doenças , Hipersensibilidade Alimentar/etiologia , Animais , Hipersensibilidade Alimentar/prevenção & controle , Hipersensibilidade Alimentar/terapia , Humanos , CamundongosRESUMO
Individuals with atopic dermatitis (AD) are susceptible to a severe, potentially fatal, systemic infection and inflammatory response following exposure to Vaccinia virus (VV). IL-10 acts both as an inducer of Th2 responses and as a regulator of T cell activation. It has been shown to limit skin inflammation elicited by contact sensitizers. AD exacerbations have been associated with decreased IL-10 function. We used IL-10(-/-) mice to test the role of the cytokine in VV immunity. They exhibited larger primary lesions and increased cutaneous neutrophil infiltration compared to wild-type (WT) counterparts. This was associated with enhanced production of IL-17A, IL-17F and CXCL2. Paradoxically, despite intact adaptive immune responses, tissue viral burdens were increased in IL-10(-/-) mice. These findings suggest that IL-10 is important in limiting skin inflammation induced by VV and that abnormal IL-17-driven neutrophil recruitment at the primary infection site in the skin results in increased systemic viral dissemination.
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Dermatite Atópica/imunologia , Dermatite Atópica/virologia , Interleucina-10/imunologia , Interleucina-17/imunologia , Erupção Variceliforme de Kaposi/imunologia , Erupção Variceliforme de Kaposi/virologia , Vaccinia virus/imunologia , Imunidade Adaptativa , Animais , Dermatite Atópica/genética , Dermatite Atópica/patologia , Modelos Animais de Doenças , Interleucina-10/genética , Interleucina-17/genética , Erupção Variceliforme de Kaposi/genética , Erupção Variceliforme de Kaposi/patologia , Camundongos , Camundongos Knockout , Neutrófilos/imunologia , Carga ViralRESUMO
BACKGROUND: The skin of patients with atopic dermatitis (AD) has defects in keratinocyte differentiation, particularly in expression of the epidermal barrier protein filaggrin. AD skin lesions are often exacerbated by Staphylococcus aureus-mediated secretion of the virulence factor α-toxin. It is unknown whether lack of keratinocyte differentiation predisposes to enhanced lethality from staphylococcal toxins. OBJECTIVE: We investigated whether keratinocyte differentiation and filaggrin expression protect against cell death induced by staphylococcal α-toxin. METHODS: Filaggrin-deficient primary keratinocytes were generated through small interfering RNA gene knockdown. RNA expression was determined by using real-time PCR. Cell death was determined by using the lactate dehydrogenase assay. Keratinocyte cell survival in filaggrin-deficient (ft/ft) mouse skin biopsies was determined based on Keratin 5 staining. α-Toxin heptamer formation and acid sphingomyelinase expression were determined by means of immunoblotting. RESULTS: We found that filaggrin expression, occurring as the result of keratinocyte differentiation, significantly inhibits staphylococcal α-toxin-mediated pathogenicity. Furthermore, filaggrin plays a crucial role in protecting cells by mediating the secretion of sphingomyelinase, an enzyme that reduces the number of α-toxin binding sites on the keratinocyte surface. Finally, we determined that sphingomyelinase enzymatic activity directly prevents α-toxin binding and protects keratinocytes against α-toxin-induced cytotoxicity. CONCLUSIONS: The current study introduces the novel concept that S aureus α-toxin preferentially targets and destroys filaggrin-deficient keratinocytes. It also provides a mechanism to explain the increased propensity for S aureus-mediated exacerbation of AD skin disease.
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Toxinas Bacterianas/toxicidade , Proteínas Hemolisinas/toxicidade , Proteínas de Filamentos Intermediários/biossíntese , Queratinócitos/efeitos dos fármacos , Queratinócitos/imunologia , Esfingomielina Fosfodiesterase/imunologia , Esfingomielina Fosfodiesterase/metabolismo , Animais , Toxinas Bacterianas/imunologia , Morte Celular/efeitos dos fármacos , Morte Celular/imunologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/imunologia , Células Cultivadas , Dermatite Atópica/imunologia , Dermatite Atópica/microbiologia , Dermatite Atópica/patologia , Proteínas Filagrinas , Proteínas Hemolisinas/imunologia , Humanos , Proteínas de Filamentos Intermediários/deficiência , Proteínas de Filamentos Intermediários/imunologia , Queratinócitos/citologia , Queratinócitos/enzimologia , Camundongos , Camundongos Endogâmicos BALB C , Pele/citologia , Pele/imunologia , Pele/metabolismo , Pele/microbiologia , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/metabolismoRESUMO
BACKGROUND: Sensitization to food antigen can occur through cutaneous exposure. OBJECTIVE: We sought to test the hypothesis that epicutaneous sensitization with food antigen predisposes to IgE-mediated anaphylaxis on oral allergen challenge. METHODS: BALB/c mice were epicutaneously sensitized by repeated application of ovalbumin (OVA) to tape-stripped skin over 7 weeks or orally immunized with OVA and cholera toxin (CT) weekly for 8 weeks and then orally challenged with OVA. Body temperature was monitored, and serum mouse mast cell protease 1 levels were determined after challenge. Tissue mast cell (MC) counts were examined by using chloroacetate esterase staining. Levels of serum OVA-specific IgE and IgG(1) antibodies and cytokines in supernatants of OVA-stimulated splenocytes were measured by means of ELISA. Serum IL-4 levels were measured by using an in vivo cytokine capture assay. RESULTS: Epicutaneously sensitized mice exhibited expansion of connective tissue MCs in the jejunum, increased serum IL-4 levels, and systemic anaphylaxis after oral challenge, as evidenced by decreased body temperature and increased serum mouse mast cell protease 1 levels. Intestinal MC expansion and anaphylaxis were IgE dependent because they did not occur in epicutaneously sensitized IgE(-/-) mice. Mice orally immunized with OVA plus CT did not have increased serum IL-4 levels, expanded intestinal MCs, or anaphylaxis after oral challenge, despite OVA-specific IgE levels and splenocyte cytokine production in response to OVA stimulation, which were comparable with those of epicutaneously sensitized mice. CONCLUSION: Epicutaneously sensitized mice, but not mice orally immunized with antigen plus CT, have expansion of intestinal MCs and IgE-mediated anaphylaxis after single oral antigen challenge. IgE is necessary but not sufficient for food anaphylaxis, and MC expansion in the gut can play an important role in the development of anaphylaxis.
Assuntos
Anafilaxia/imunologia , Hipersensibilidade Alimentar/imunologia , Imunoglobulina E/imunologia , Jejuno/imunologia , Mastócitos/imunologia , Pele/imunologia , Administração Cutânea , Alérgenos/imunologia , Animais , Anticorpos/imunologia , Antígenos/imunologia , Temperatura Corporal/imunologia , Quimiocina CCL2/imunologia , Toxina da Cólera/imunologia , Imunoglobulina G/imunologia , Interleucina-4/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologiaRESUMO
The F-BAR domain containing protein CIP4 (Cdc42 interacting protein 4) interacts with Cdc42 and WASP/N-WASP and is thought to participate in the assembly of filamentous actin. CIP4(-/-) mice had normal T- and B-lymphocyte development but impaired T cell-dependent antibody production, IgG antibody affinity maturation, and germinal center (GC) formation, despite an intact CD40L-CD40 axis. CIP4(-/-) mice also had impaired contact hypersensitivity (CHS) to haptens, and their T cells failed to adoptively transfer CHS. Ovalbumin-activated CD4(+) effector T cells from CIP4(-/-)/OT-II mice migrated poorly to antigen-challenged skin. Activated CIP4(-/-) T cells exhibited impaired adhesion and polarization on immobilized VCAM-1 and ICAM-1 and defective arrest and transmigration across murine endothelial cell monolayers under shear flow conditions. These results demonstrate an important role for CIP4 in integrin-dependent T cell-dependent antibody responses and GC formation and in integrin-mediated recruitment of effector T cells to cutaneous sites of antigen-driven immune reactions.
Assuntos
Movimento Celular , Integrinas/imunologia , Proteínas Associadas aos Microtúbulos/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia , Animais , Linfócitos B/imunologia , Adesão Celular , Polaridade Celular , Dermatite Alérgica de Contato/genética , Dermatite Alérgica de Contato/imunologia , Molécula 1 de Adesão Intercelular/imunologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/deficiência , Antígenos de Histocompatibilidade Menor , Molécula 1 de Adesão de Célula Vascular/imunologiaRESUMO
The human pathogens enteropathogenic Escherichia coli (EPEC) and vaccinia virus trigger actin assembly in host cells by activating the host adaptor Nck and the actin nucleation promoter neural Wiskott-Aldrich syndrome protein (N-WASP). EPEC translocates effector molecules into host cells via type III secretion, and the interaction between the translocated intimin receptor (Tir) and the bacterial membrane protein intimin stimulates Nck and N-WASP recruitment, leading to the formation of actin pedestals beneath adherent bacteria. Vaccinia virus also recruits Nck and N-WASP to generate actin tails that promote cell-to-cell spread of the virus. In addition to Nck and N-WASP, WASP-interacting protein (WIP) localizes to vaccinia virus tails, and inhibition of actin tail formation upon ectopic expression of WIP mutants led to the suggestion that WIP is required for this process. Similar studies of WIP mutants, however, did not affect the ability of EPEC to form actin pedestals, arguing against an essential role for WIP in EPEC-induced actin assembly. In this study, we demonstrate that Nck and N-WASP are normally recruited by vaccinia virus and EPEC in the absence of WIP, and neither WIP nor the WIP family members CR16 and WIRE/WICH are essential for pathogen induced actin assembly. In addition, although Nck binds EPEC Tir directly, N-WASP is required for its localization during pedestal formation. Overall, these data highlight similar pathogenic strategies shared by EPEC and vaccinia virus by demonstrating a requirement for both Nck and N-WASP, but not WIP or WIP family members in pathogen-induced actin assembly.
Assuntos
Actinas/metabolismo , Proteínas de Transporte/metabolismo , Escherichia coli Enteropatogênica/patogenicidade , Vaccinia virus/patogenicidade , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Células Cultivadas , Proteínas do Citoesqueleto , Escherichia coli Enteropatogênica/metabolismo , Fibroblastos , Camundongos , Camundongos Knockout , Proteínas Oncogênicas/metabolismo , Vaccinia virus/metabolismo , Proteína Neuronal da Síndrome de Wiskott-Aldrich/metabolismoRESUMO
Atopic dermatitis (AD) is a common allergic inflammatory skin disease caused by a combination of intense pruritus, scratching, and epicutaneous (e.c.) sensitization with allergens. To explore the roles of IL-21 and IL-21 receptor (IL-21R) in AD, we examined skin lesions from patients with AD and used a mouse model of allergic skin inflammation. IL-21 and IL-21R expression was upregulated in acute skin lesions of AD patients and in mouse skin subjected to tape stripping, a surrogate for scratching. The importance of this finding was highlighted by the fact that both Il21r-/- mice and WT mice treated with soluble IL-21R-IgG2aFc fusion protein failed to develop skin inflammation after e.c. sensitization of tape-stripped skin. Adoptively transferred OVA-specific WT CD4+ T cells accumulated poorly in draining LNs (DLNs) of e.c. sensitized Il21r-/- mice. This was likely caused by both DC-intrinsic and nonintrinsic effects, because trafficking of skin DCs to DLNs was defective in Il21r-/- mice and, to a lesser extent, in WT mice reconstituted with Il21r-/- BM. More insight into this defect was provided by the observation that skin DCs from tape-stripped WT mice, but not Il21r-/- mice, upregulated CCR7 and migrated toward CCR7 ligands. Treatment of epidermal and dermal cells with IL-21 activated MMP2, which has been implicated in trafficking of skin DCs. These results suggest an important role for IL-21R in the mobilization of skin DCs to DLNs and the subsequent allergic response to e.c. introduced antigen.
Assuntos
Dermatite Atópica , Imunização , Inflamação/imunologia , Receptores de Interleucina-21/imunologia , Pele , Transferência Adotiva , Animais , Células Cultivadas , Dermatite Atópica/imunologia , Dermatite Atópica/patologia , Modelos Animais de Doenças , Ativação Enzimática , Feminino , Humanos , Inflamação/induzido quimicamente , Inflamação/patologia , Interleucinas/genética , Interleucinas/imunologia , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Ovalbumina/imunologia , Ovalbumina/farmacologia , Receptores CCR7/genética , Receptores CCR7/imunologia , Receptores de Interleucina-21/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Pele/imunologia , Pele/patologia , Baço/citologia , Baço/imunologiaRESUMO
The Wiskott-Aldrich syndrome (WAS) interacting protein (WIP) stabilizes the WAS protein (WASP), the product of the gene mutated in WAS. WIP-deficient T cells have low WASP levels, limiting the usefulness of WIP KO mice in defining the role of WIP in T cell function. To define this role, we compared WIP/WASP double KO (DKO) mice to WASP KO mice on DO11.10 background. T cell development was normal in both strains, but peripheral T cell numbers were significantly decreased in DKO mice. WASP KO T cells proliferated and secreted IL-2 normally in response to OVA peptide (OVAp). In contrast, T cells from DKO mice proliferated poorly in response to OVAp in vitro, and cutaneous hapten hypersensitivity was deficient in these mice. DKO T cells up-regulated CD25 expression and secreted normal amounts of IL-2 after antigen stimulation, but had defective response to IL-2, evidenced by failure to further up-regulate CD25 expression, phosphorylate STAT5, and induce expression of STAT5-dependent genes. DKO, but not WASP KO, T cells had a disrupted subcortical actin cytoskeleton and impaired actin polymerization after T cell antigen receptor (TCR) ligation. These results indicate that WIP is essential for IL-2 signaling and responsiveness in T cells, possibly because of its critical role in TCR-triggered actin cytoskeletal reorganization.
Assuntos
Proteínas de Transporte/fisiologia , Interleucina-2/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/imunologia , Actinas/metabolismo , Actinas/ultraestrutura , Animais , Antígenos/imunologia , Proteínas de Transporte/genética , Proliferação de Células , Proteínas do Citoesqueleto , Citoesqueleto/imunologia , Citoesqueleto/ultraestrutura , Interleucina-2/farmacologia , Camundongos , Camundongos Knockout , Receptores de Interleucina-2/biossíntese , Linfócitos T/efeitos dos fármacos , Timo/crescimento & desenvolvimento , Timo/imunologia , Proteína da Síndrome de Wiskott-Aldrich/genética , Proteína da Síndrome de Wiskott-Aldrich/fisiologiaRESUMO
Eczema vaccinatum (EV) is a complication of smallpox vaccination occurring in patients with atopic dermatitis. In affected individuals, vaccinia virus (VV) spreads through the skin, resulting in large primary lesions and satellite lesions, and infects internal organs. BALB/c mice inoculated with VV at sites of Th2-biased allergic skin inflammation elicited by epicutaneous ovalbumin (OVA) sensitization exhibited larger primary lesions that were erosive, more satellite lesions, and higher viral loads in skin and internal organs than mice inoculated in saline-exposed skin, unsensitized skin, or skin sites with Th1-dominant inflammation. VV inoculation in OVA-sensitized skin induced marked local expression of IL-17 transcripts and massive neutrophil infiltration compared to VV inoculation in saline-exposed skin. Treatment with anti-IL-17 decreased the size of primary lesions, numbers of satellite lesions, and viral loads. Addition of IL-17 promoted VV replication in skin explants. These results suggest that IL-17 may be a potential therapeutic target in EV.