Shin Yoshino

IL-17A Promotes the Exacerbation of IL-33–Induced Airway Hyperresponsiveness by Enhancing Neutrophilic Inflammation via CXCR2 Signaling in Mice

Neutrophilic airway inflammation is a hallmark of patients with severe asthma. Although we have reported that both IL-33 and IL-17A contributed to IgE-mediated neutrophilic inflammation in mice, the relationship remains unclear. In this article, we examined how IL-17A modifies IL-33–induced neutrophilic inflammation and airway hyperresponsiveness (AHR). IL-33 was intratracheally administered to BALB/c mice on days 0–2; furthermore, on day 7, the effect of the combination of IL-33 and IL-17A was evaluated. Compared with IL-33 or IL-17A alone, the combination exacerbated neutrophilic inflammation and AHR, associated with more increased levels of lung glutamic acid-leucine-arginine+ CXC chemokines, including CXCL1, CXCL2, and CXCL5, and infiltration by alveolar macrophages expressing CXCR2. Treatment with anti-CXCR2 mAb or depletion of alveolar macrophages repressed neutrophilic inflammation and AHR; in addition, depletion of neutrophils suppressed AHR. These findings prompted us to examine the role of CXCR2 in IgE-sensitized mice; a single treatment with anti-CXCR2 mAb in the seventh Ag challenge inhibited late-phase airway obstruction, AHR, and neutrophilic inflammation. In addition to inhibition, multiple treatments during the fourth to seventh challenge attenuated early-phase airway obstruction, eosinophilic inflammation, and goblet cell hyperplasia associated with the reduction of Th2 cytokine production, including IL-4, IL-5, and IL-13. Collectively, IL-33 cooperated with IL-17A to exacerbate AHR by enhancing neutrophilic inflammation via CXCR2 signaling; furthermore, CXCR2 signaling derived Th2 responses. We thus suggest the underlying mechanisms of IL-33 and IL-17A in allergic asthma and CXCR2 as potential therapeutic targets for the disease.

Interleukin-33 and alveolar macrophages contribute to the mechanisms underlying the exacerbation of IgE-mediated airway inflammation and remodelling in mice.

Allergen‐specific IgE has long been regarded as a major molecular component of allergic asthma. Additionally, there is increasing evidence of the important roles of interleukin‐33 (IL‐33) in the disease. Here, we show that IL‐33 and alveolar macrophages play essential roles in the exacerbation of IgE‐mediated airway inflammation and remodelling. BALB/c mice passively sensitized with ovalbumin (OVA)‐specific IgE monoclonal antibody (mAb) were challenged with OVA seven times intratracheally. The seventh challenge exacerbated airway inflammation and remodelling compared with the fourth challenge; furthermore, markedly increased expression of IL‐33 in the lungs was observed at the fourth and seventh challenges. When anti‐IL‐33 or anti‐ST2 antibody was administered during the fourth to seventh challenge, airway inflammation and remodelling were significantly inhibited at the seventh challenge. Because increases of IL‐33+ and ST2+ alveolar macrophages and ST2+ CD4+ T cells in the lungs were observed at the fourth challenge, the roles of macrophages and CD4+ cells were investigated. Depletion of macrophages by 2‐chloroadenosine during the fourth to seventh challenge suppressed airway inflammation and remodelling, and IL‐33 production in the lung at the seventh challenge; additionally, anti‐CD4 mAb inhibited airway inflammation, but not airway remodelling and IL‐33 production. Meanwhile, treatment with 2‐chloroadenosine or anti‐CD4 mAb decreased IL‐33‐induced airway inflammation in normal mice; airway remodelling was repressed only by 2‐chloroadenosine. These results illustrate that macrophage‐derived IL‐33 contributes to the exacerbation of IgE‐mediated airway inflammation by mechanisms associated with macrophages and CD4+ cells, and airway remodelling through the activation of macrophages.

Important role of neutrophils in the late asthmatic response in mice

AIMSnNeutrophils have been found increasingly in the lungs of patients with severe asthma; however, it is unclear whether the neutrophils contribute to the induction of the airway obstruction. We determined using a murine model whether neutrophils are involved in the late asthmatic response (LAR), and analyzed mechanisms underlying the antigen-induced airway neutrophilia.nnnMAIN METHODSnBALB/c mice sensitized by ovalbumin (OVA)+Al(OH)(3) were challenged 4 times by intratracheal administration of OVA. Airway mechanics were measured as specific airway resistance.nnnKEY FINDINGSnInduction of the LAR after the 4th challenge coincided with airway neutrophilia. In contrast, eosinophil infiltration was established prior to the 4th challenge. A treatment with an anti-Gr-1 monoclonal antibody (mAb) before the 4th challenge selectively suppressed increases in the neutrophil number and myeloperoxidase (MPO) level in bronchoalveolar lavage fluid (BALF), and attenuated the magnitude of LAR by 60-70%. Selective suppression of eosinophilia by anti-IL-5 mAb had little effect on the LAR. The increases in neutrophil number and MPO level were partially inhibited by an anti-CD4 mAb treatment. The CD4(+) cell depletion also significantly inhibited increases in neutrophil chemoattractants, IL-17A, keratinocyte-derived chemokine (KC) and macrophage inflammatory protein (MIP)-2 in BALF. However, blockade of FcγRII/III failed to suppress the neutrophilia.nnnSIGNIFICANCEnThese data suggest that neutrophils are key inducers of the LAR, and that the antigen-induced neutrophilia is partially dependent on activated CD4(+) cells that are involved in the production of IL-17A, KC and MIP-2.

Complement C3a-Induced IL-17 Plays a Critical Role in an IgE-Mediated Late-Phase Asthmatic Response and Airway Hyperresponsiveness via Neutrophilic Inflammation in Mice

Allergen-specific IgE plays an essential role in the pathogenesis of allergic asthma. Although there has been increasing evidence suggesting the involvement of IL-17 in the disease, the relationship between IL-17 and IgE-mediated asthmatic responses has not yet been defined. In this study, we attempted to elucidate the contribution of IL-17 to an IgE-mediated late-phase asthmatic response and airway hyperresponsiveness (AHR). BALB/c mice passively sensitized with an OVA-specific IgE mAb were challenged with OVA intratracheally four times. The fourth challenge caused a late-phase increase in airway resistance associated with elevated levels of IL-17+CD4+ cells in the lungs. Multiple treatments with a C3a receptor antagonist or anti-C3a mAb during the challenges inhibited the increase in IL-17+CD4+ cells. Meanwhile, a single treatment with the antagonist or the mAb at the fourth challenge suppressed the late-phase increase in airway resistance, AHR, and infiltration by neutrophils in bronchoalveolar lavage fluid. Because IL-17 production in the lungs was significantly repressed by both treatments, the effect of an anti–IL-17 mAb was examined. The late-phase increase in airway resistance, AHR, and infiltration by neutrophils in bronchoalveolar lavage fluid was inhibited. Furthermore, an anti–Gr-1 mAb had a similar effect. Collectively, we found that IgE mediated the increase of IL-17+CD4+ cells in the lungs caused by repeated Ag challenges via C3a. The mechanisms leading to the IgE-mediated late-phase asthmatic response and AHR are closely associated with neutrophilic inflammation through the production of IL-17 induced by C3a.

Preventive and therapeutic effects of rapamycin, a mammalian target of rapamycin inhibitor, on food allergy in mice

Because few curative treatments are available for food allergy, we investigated the therapeutic potential of rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, on mouse food allergy.

Tyrosine kinase inhibitor sunitinib relieves systemic and oral antigen-induced anaphylaxes in mice.

To cite this article: Yamaki K, Yoshino S. Tyrosine kinase inhibitor sunitinib relieves systemic and oral antigen‐induced anaphylaxes in mice. Allergy 2012; 67: 114–122.

Production of interleukin (IL)-33 in the lungs during multiple antigen challenge-induced airway inflammation in mice, and its modulation by a glucocorticoid.

Although interleukin (IL)-33 is a candidate aggravator of asthma, the cellular sources of IL-33 in the lungs during the progression of antigen-induced airway inflammation remain unclear. Furthermore, it has not been determined whether the antigen-induced production of IL-33 can be pharmacologically modulated in vivo. In this study, we examined the production of IL-33 in the lungs of sensitized mice during multiple intratracheal challenges with the antigen, ovalbumin. The 1st challenge clearly induced the IL-33 production in the lungs, and it was enhanced by the 2nd-4th challenges. IL-33 mRNA transcription was also induced after these challenges. An immunohistochemical analysis revealed that the cellular sources of IL-33 after the 1st challenge were mainly bronchial epithelial cells, while those after the 3rd challenge were not only the epithelial cells, but also inflammatory cells that infiltrated the lungs. Flow cytometric analyses indicated that approximately 20% and 10% of the IL-33-producing cells in the lungs were M2 macrophages and conventional dendritic cells, respectively. A systemic treatment with dexamethasone before the 1st challenge potently suppressed the IL-33 production. When dexamethasone was administered before the respective challenges, production of the IL-33 protein and the infiltration of IL-33-producing M2 macrophages and dendritic cells into the lungs in the 3rd challenge were also suppressed. In conclusion, the cellular sources of IL-33 in the lungs were dynamically altered during multiple challenges: not only bronchial epithelial cells, but also the M2 macrophages and dendritic cells that infiltrated the lungs produced IL-33. The production of IL-33 was susceptible to the glucocorticoid treatment.

Regulatory role of antigen-induced interleukin-10, produced by CD4(+) T cells, in airway neutrophilia in a murine model for asthma.

It has been suggested that interleukin (IL)-10 exerts immunosuppressive effects on allergic inflammation, including asthma, mainly through inhibition of Th2 cell-mediated eosinophilic airway inflammation. In a model of experimental asthma utilizing multiple intratracheal antigen challenges in sensitized mice, IL-10 production as well as eosinophilia and neutrophilia in the lung were induced by the multiple challenges. In this study, we set out to reveal the cellular source of endogenously produced IL-10, and the roles of IL-10 in airway leukocyte inflammation using an anti-IL-10 receptor monoclonal antibody. Balb/c mice were sensitized i.p. with ovalbumin+Al(OH)(3), and then challenged by intratracheal administration of ovalbumin 4 times. Flow cytometric analyses revealed that the cellular source of IL-10 was CD4(+) T cells lacking the transcription factor, forkhead box P3. Treatment with anti-IL-10 receptor monoclonal antibody prior to the 4th challenge significantly augmented airway neutrophilia as well as the production of IL-1β, and CXC chemokines, keratinocyte-derived chemokine (KC) and macrophage inflammatory protein (MIP)-2, but not airway eosinophilia, Th2 cytokine (IL-4 and IL-5) production, or a late-phase increase in specific airway resistance. Approximately 40% of IL-10 receptor(+) cells expressed the macrophage marker F4/80, whereas only 3-4% of the IL-10 receptor(+) cells were granulocyte differentiation antigen (Gr)-1(high) cells (neutrophils). In conclusion, multiple airway antigen challenges induced the proliferation of IL-10-expressing CD4(+) T cells in regulating airway neutrophilia. Systemic blockade of IL-10 function coincided with increases in IL-1β and CXC chemokines. Thus, IL-1β and CXC chemokines may be targets for development of novel pharmacotherapy for neutrophilic asthma.

Roles of basophils and mast cells infiltrating the lung by multiple antigen challenges in asthmatic responses of mice

Mast cell hyperplasia has been observed in the lungs of mice with experimental asthma, but few reports have studied basophils. Here, we attempted to discriminate and quantify mast cells and basophils in the lungs in a murine asthma model, determine if both cells were increased by multiple antigen challenges and assess the roles of those cells in asthmatic responses.

Establishment and characterization of a murine model for allergic asthma using allergen-specific IgE monoclonal antibody to study pathological roles of IgE

Allergen-specific IgE has long been regarded as a major molecular component of allergic asthma. Although IgE plays a central role in the early asthmatic response, its roles in the chronic phase, such as the late asthmatic response, airway hyperresponsiveness (AHR), and airway remodeling (goblet cell hyperplasia and subepithelial fibrosis) have not yet been defined well. In this study, we investigated the hypothesis that chronic responses could be induced by IgE-dependent mechanisms. BALB/c mice passively sensitized with an ovalbumin (OVA)-specific IgE monoclonal antibody (mAb) were repeatedly challenged with intratracheal administration of OVA. The first challenge induced early phase airway narrowing without any late response, but the fourth challenge caused not only an early but also a late phase response, AHR, and goblet cell hyperplasia. Macrophages, lymphocytes and neutrophils, but not eosinophils, were significantly increased in the lung 24h after the fourth challenge. Interestingly, levels of OVA-specific IgG1 in serum increased by multiple antigen challenges. A C3a receptor antagonist inhibited the late asthmatic response, AHR, and infiltration by neutrophils. In contrast, no late response, goblet cell hyperplasia, inflammatory cells, or production of IgG1 was observed in severe combined immunodeficient mice. On the other hand, seven challenges in BALB/c mice induced subepithelial fibrosis associated with infiltration by eosinophils. In conclusion, the allergic asthmatic responses induced by passive sensitization with IgE mAb can provide a useful model system to study the pathological roles of IgE in acute and chronic phases of allergic asthma.