Article

Untangling the Complex Web of IL-4-and IL-13-Mediated Signaling Pathways

Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
Science Signaling (Impact Factor: 7.65). 02/2008; 1(51):pe55. DOI: 10.1126/scisignal.1.51.pe55
Source: PubMed

ABSTRACT Unraveling the exact signaling events mediating the distinct functions of the T cell-derived cytokines interleukin-4 (IL-4) and IL-13 has been challenging because they are structurally similar and share a functional signaling receptor chain. A study now proposes a potential molecular mechanism to explain the functional differences between IL-4 and IL-13 that involves the ability of IL-4, but not IL-13, to effectively activate the insulin receptor substrate-2 (IRS-2) signaling cascade through binding to its receptor. A better understanding of the interactions of IL-4 and IL-13 with their cognate receptors may facilitate the development of therapies without unintended side effects.

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    • "Th2 cells secrete a panel of cytokines with several overlapping functions including Interleukin-4 (IL-4), IL- 5, IL-13, and granulocyte-macrophage colony stimulating factor (GM-CSF). By mediating differentiation of the Th2 subpopulation and eosinophils, as well as modulating Bcell proliferation and IgE switching, the Th2 cytokines are thought to play a prominent role in asthma [5] [6]. The sentinel Th1 cytokine, interferon gamma (IFNγ), and IL- 12 reciprocally stimulate their production and function during cell-mediated immunity and development of na¨ıve T lymphocytes into Th1 cells. "
    Mediators of Inflammation 03/2013; · 3.24 Impact Factor
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    • "Th2 cells secrete a panel of cytokines with several overlapping functions including Interleukin-4 (IL-4), IL- 5, IL-13, and granulocyte-macrophage colony stimulating factor (GM-CSF). By mediating differentiation of the Th2 subpopulation and eosinophils, as well as modulating Bcell proliferation and IgE switching, the Th2 cytokines are thought to play a prominent role in asthma [5] [6]. The sentinel Th1 cytokine, interferon gamma (IFNγ), and IL- 12 reciprocally stimulate their production and function during cell-mediated immunity and development of na¨ıve T lymphocytes into Th1 cells. "
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    ABSTRACT: Background. Allergic asthma is showed an increase in Th2-cytokine and IgE levels and an accumulation activation of Th2 cells, eosinophils and mast cells. However, recent studies focused on cell-based mechanisms for the pathogenesis of allergic asthma. Objectives. In this study, we compare the anti-IgE treatment modality in the dynamics of immune system cytokine levels in severe persistent asthma (SPA) patients who had no other any allergic disease, newly diagnosed allergic asthma patients and healthy volunteers. Study Design. The study population consisted of 14 SPA patients, 14 newly diagnosed allergic asthma patients and 14 healthy volunteers included as controls. Cytokine levels were measured. Total and specific IgE levels of anti-IgE monoclonal antibody treated patients, serum high-sensitivity C-reactive protein (hsCRP) levels, FEV1/FVC rates and asthma control test (ACT) were measured for the clinical follow-up. Results. We observed that SPA patients presented increasing levels of IL-8, IL-10, TGF-β and GCSF during the anti-IgE treatment in period of sampling times at 4 months and 18 months. However this increase was not correlated neither with serum hsCRP levels nor FEV1/FVC rates. Conclusions. Our study gives a different perspective for the SPA and anti-IgE immunotherapy efficacy at the cell cytokine-linked step.
    Mediators of Inflammation 12/2012; 2012:720976. DOI:10.1155/2012/720976 · 3.24 Impact Factor
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    ABSTRACT: Asthma is a chronic disease characterised by variable airflow obstruction, bronchial hyperresponsiveness and airways inflammation. At an immunological level Th2 inflammation and the presence of activated eosinophils and mast cells are key features of asthma. ST2, the receptor for the novel cytokine IL-33, is expressed upon Th2 lymphocytes and mast cells but its role in clinical and experimental asthma remains unclear. IL-33 has been shown to induce local and systemic eosinophilia when administered to the peritoneum of mice. In this thesis I have set out to test the hypothesis that the activation of mast cells by IL-33 acting on cell surface ST2 plays a critical role in allergic airways inflammation. I began by studying the function of ST2 on mast cells in vitro. I found that ST2 was expressed at an early stage of development, and correlated closely with the expression of the stem cell factor receptor (c-kit), a marker present on mast cells from a progenitor stage. Despite this mast cells generated form ST2 gene deleted mice proliferated and matured normally. When mast cells were activated by IL-33, acting in an ST2-dependent manner, pro-inflammatory cytokines and chemokines were released that have potential roles in asthma, specifically IL-6, IL-13, MIP-1α and MCP-1. To extend these findings I looked at the role of ST2 in allergic airways inflammation. I first optimised and validated an ovalbumin and adjuvant based ‘short’ twelve day model of murine asthma and demonstrated that ST2 gene deletion results in attenuated eosinophilic inflammation. In addition to being ST2 dependent it is possible that this adjuvant based short model is mast cell dependent, unlike longer adjuvant based models which are mast cell and ST2 independent. Therefore I went on to study an adjuvant-free model of asthma which has been demonstrated to be mast cell dependent. In this adjuvant-free model of asthma the airway inflammation was attenuated in ST2 gene deficient mice compared with wild type mice, while AHR was unaffected. There was an associated reduction in IgE production and thoracic lymph node recall Th2 cytokine responses. I then examined the effect of ST2 activation in the lungs. When IL-33 was administered directly to the airways of naïve mice it induced the features of experimental asthma. There was extensive eosinophilic inflammation within the lung tissue and airspaces. The Th2 cytokines IL-5 and IL-13, and the eosinophil chemoattractant chemokines eotaxin-1 and eotaxin-2 were detected at increased concentrations. Significant airways hyperresponsiveness was also generated. Using ST2 gene deleted mice I demonstrated that these effects were ST2 specific. Although I have shown that mast cells are activated by IL-33 in vitro, I used mast cell deficient mice to demonstrate that the eosinophilic inflammation generated by IL-33 is unaffected by the absence of mast cells. These data show that IL-33 can induce in the lungs the cardinal pathological characteristics of asthma, and that it appears to act upstream of other important mediators such as IL-13 and the eotaxins. Furthermore the IL-33 receptor ST2 is required in an adjuvant free model of asthma, which is more akin to human disease. Placing these findings in the context of recent evidence that IL-33 is released by structural cells in response to damage or injury suggests that IL-33 may play a key role in initiating the immunological features of clinical asthma. As a consequence of this position in the hierarchy of inflammation IL-33 offers a promising direct target for novel biological therapies in asthma.
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