The IL-13 signaling pathway appears to be an alternative pathway for IL-4 signaling in humans (31C33). accompanied by improved airway reactivity (1C6). The cytokine IL-4 offers pleiotropic effects and appears to play a key part in the pathogenesis of atopic diseases (7, 8). IL-4Cdeficient (IL-4?/?) mice fail to develop both increase in the level of IgE in serum (9C12) and eosinophil recruitment into airways (11, 12). Moreover, the airway hyperreactivity normally resulting from allergen challenge is definitely abolished in IL-4?/? mice (12) and mice treated with antiCIL-4 antibody (13). These data display that IL-4 is definitely a central mediator in the pathogenesis of sensitive asthma. Transmission transducers and activators of transcription (STAT) proteins are family of transcription factors that mediate many cytokine-induced reactions (14). STAT6 is definitely tyrosine phosphorylated and triggered in response to IL-4 (15, 16). Much like IL-4?/? mice (9, 10), STAT6-deficient (STAT6?/?) mice also abrogate IL-4Cmediated functions including Th2 differentiation, manifestation of cell surface markers, and Ig class Rabbit Polyclonal to 5-HT-3A switching to IgE (17C19). These findings demonstrate that STAT6 is required for IL-4Cspecific functions, despite the living of multiple signaling pathways triggered by IL-4 (20, 21). However, it is still unclear whether a STAT6-mediated transmission is also in the pathogenesis of both the peribronchial swelling and the airway hyperreactivity. In this study, we examined the functions played by STAT6 inside a murine model of allergen-induced airway swelling. Our findings display that STAT6 may play a critical part in the development of the pathophysiology of allergic asthma. Materials and Methods Animals. C57/BL6 mice with targeted disruption of the gene encoding STAT6 (STAT6?/? mice) were generated in the Division of Biochemistry, Hyogo College of Medicine (Hyogo, Japan), as previously reported (17), and inbred in Experimental Technology Study Center, Daiichi Pharmaceutical Co., Ltd. (Tokyo, Japan). Age-matched C57/BL6 female mice were purchased from SLC (Shizuoka, Japan). All animals were housed under specific pathogen-free conditions, and experienced free access to commercial diet and water. Immunization and Exposure of Mice. On the 1st day of the experiment (day time 0) and day time 12, 5- or 6-wk-old woman mice were actively immunized by intraperitoneal injection of 50 g of OVA (for 10 min. Serum IgE level was identified with a commercial ELISA kit (Yamasa, Chiba, Japan). Concentrations of IgM were determined by ELISA using goat antiCmouse IgM (Southern Biochemistry Assoc., Birmingham, AL) mainly because capture antibody and goat antiCmouse IgM labeled with biotin (Southern Biochemistry Assoc.) mainly because detection antibody (17). ZM223 Bronchoalveolar Lavage. The trachea was cannulated and the airway lumina were washed twice with 0.5 ml of phosphate-buffered saline (free of ionized calcium and magnesium) supplemented with 0.05 mM sodium EDTA ( 0.05). Results demonstrated are from a single experiment representative of three independent experiments. Discussion In this study, we demonstrate that pulmonary eosinophilia, airway hyperreactivity, and lung damage usually seen in mice immunized and challenged with antigen are not observed in STAT6?/? mice, suggesting that STAT6 activation takes on an essential part in the pathogenesis of sensitive airway swelling. Bronchial asthma is definitely a chronic airway disease with reversible airway obstruction and airway swelling. The pathophysiological changes in asthma are characterized by improved serum IgE level, eosinophil infiltration around airways, bronchial ZM223 mucosal injury, and airway hyperreactivity (1C6). This pathophysiologic process of asthma is thought to involve T helper cells having a Th2 cytokine phenotype. It has been reported that depletion of cluster of differentiation (CD)4-positive lymphocytes prevents antigen-induced airway ZM223 reactivity and recruitment of eosinophils to the airways (22). Bronchoalveolar lymphocytes and T cell clones from airway mucosa with sensitive respiratory disorders synthesized and released IL-3, -4, -5, and GM-CSF, indicating predominant differentiation of Th2 (23, 24). Moreover, either IL-4 (12) or -5 (25) deficiency abolishes airway hyperreactivity in mouse asthma models. Thus, there is no doubt that IL-4 and -5 are key cytokines participating in the various aspects of manifestations of asthma. However, you will find apparently discrepant reports on their relative importance in airway hyperreactivity. Corry et al. showed that neutralization of IL-4 using monoclonal antibodies abrogated airway hyperreactivity but experienced little effect on the influx of eosinophils, and that administration of antiCIL-5 antibodies suppressed eosinophil recruitment but experienced no effect on the subsequent airway response (13). These data are similar to what was found in.