GliSODin® prevents airway inflammation by inhibiting T-cell differentiation and activation in a mouse model of asthma.

Background: Asthma is a chronic inflammatory airway disease characterized by a prevailing type 2 inflammation, airway hyperresponsiveness, and mucus hypersecretion and is driven by various factors among which oxidative molecules, called reactive oxygen species (ROS), play a major role. Superoxide dismutases (SODs) are enzymes that constitute the first line of defense against ROS. Melon SOD-gliadin, which is known as GliSODin®, is commonly used as a nutritional supplement that has proven antioxidant properties. Objectives: In this study, we evaluated the efficacy and mechanism of action GliSODin® in the treatment of allergic asthma. Methods: House dust mite (HDM)-induced asthmatic mice were orally exposed to GliSODin®, and airway hyperresponsiveness, lung inflammation, in vitro T-cell polarization, in vivo T-cell reactivation, and blood immunoglobulin were investigated. Results: GliSODin® reduced airway hyperresponsiveness, lung innate and adaptive immune response, and HDM-specific IgE production. Coculturing CD4+ T-cell with HDM-sensitized dendritic cells and GliSODin® reduced T-cell polarization into Th2 and Th17 cells. Moreover, adoptively transferred CD4+ T cells from asthmatic mice exhibited a reduced reactivation of Th2 and Th17 cells following stimulation with HDM plus GliSODin®. Conclusion: GliSODin® abrogates asthma features and reduces CD4+ T-cell polarization and reactivation. Taken together, these data suggest that GliSODin® could be used for the management of asthma symptoms.

Allergic Sensitization Driving Immune Phenotyping and Disease Severity in a Mouse Model of Asthma.

PURPOSE: Asthma is a frequent chronic inflammatory bronchial disease affecting more than 300 million patients worldwide, 70% of whom are secondary to allergy. The diversity of asthmatic endotypes contributes to their complexity. The inter-relationship between allergen and other exposure and the airway microbiome adds to the phenotypic diversity and defines the natural course of asthma. Here, we compared the mouse models of house dust mite (HDM)-induced allergic asthma. Allergic sensitization was performed via various routes and associated with outcomes. METHODS: Mice were sensitized with HDM via the oral, nasal or percutaneous routes. Lung function, barrier integrity, immune response and microbiota composition were analyzed. RESULTS: Severe impairment of respiratory function was observed in the mice sensitized by the nasal and cutaneous paths. It was associated with epithelial dysfunction characterized by an increased permeability secondary to junction protein disruption. Such sensitization paths induced a mixed eosinophilic and neutrophilic inflammatory response with high interleukin (IL)-17 airway secretion. In contrast, orally sensitized mice showed a mild impairment of respiratory function. Epithelial dysfunction was mild with increased mucus production, but preserved epithelial junctions. Regarding lung microbiota, sensitization provoked a significant loss of diversity. At the genus level, Cutibacterium, Acinetobacter, Streptococcus and Lactobacillus were found to be modulated according to the sensitization pathway. An increase in theanti-inflammatory microbiota metabolites was observed in the oral-sensitization group. CONCLUSIONS: Our study highlights the strong impact of the sensitization route on the pathophysiology and the critical phenotypic diversity of allergic asthma in a mouse model.

Oral exposure to bisphenol A exacerbates allergic inflammation in a mouse model of food allergy.

Allergic diseases are increasing worldwide, and their precise causes are not fully understood. However, this observation can be correlated with growing chemical pollution of the environment. Bisphenol A (BPA) alters the immune system, microbiota and barrier functions. Here, we studied the effect of oral BPA at levels equivalent to human exposure to understand the mechanisms of immunological, physiological and microbial action on food allergies. In a murine model of allergy, we evaluated the effect of direct oral exposure to BPA at 4 µg/kg bw/d corresponding to tolerable daily intake (TDI). We studied symptoms, intestinal physiology and humorall and cellular immune responses during food allergy. We explored the relationship between oral exposure to BPA and changes in the gut microenvironment. Markers of food allergy and intestinal permeability were increased following exposure to BPA. We also observed a modulated humorall and T-cell response with aggravation of food allergy inflammation. Moreover, BPA exposure induced gut dysbiosis and decreased microbial diversity induced by food allergy. Altogether, these results suggest that the 2015 European Food Safety Authority (EFSA) TDI should be reviewed to consider the immunotoxicity of BPA.

The IL-15 / sIL-15Rα complex modulates immunity without effect on asthma features in mouse.

BACKGROUND: Interleukin 15 (IL-15) is a growth and modulating factor for B, T lymphocytes and natural killer cells (NK). Its action on innate and adaptive immunity is modulated by its alpha chain receptor (IL-15Rα). The IL-15/sIL-15Rα complex (IL-15Cx) increases the bioavailability and activity of the cytokine in vivo. IL-15Cx has been used in diseases to dampen IL-15 inflammation by the use of soluble IL-15Ralpha specificity. Here, we aim to evaluate the interest of IL-15Cx in a mouse model of asthma. METHODS: Using a mouse model of asthma consisting in percutaneous sensitization and intranasal challenge with total house dust mite extract, we evaluated the effect of IL-15Cx injected intraperitoneally four times after a first nasal challenge. Respiratory function was assessed by the technique of forced oscillations (Flexivent®). The effect on bronchial remodeling was evaluated by lung histology. The inflammatory status was analyzed by flow cytometry. RESULTS: We observed that the IL-15Cx modulates lung and systemic inflammation by increasing NK cells, CD8+ memory T cells and regulatory cells. However, IL-15Cx displays no effect on bronchial hyperreactivity, bronchial remodeling nor cellular bronchial infiltrate, but limits the secretion of bronchial mucus and modulates only inflammatory response in a HDM-allergic asthma murine model. CONCLUSIONS: IL-15Cx has a limited effect on immune response in asthma and has no effect on lung function in mice. Thus, it limits its therapeutic potential but might suggest a combinatory potential with other therapeutics.

[New protagonists in asthma pathophysiology]. / Nouveaux acteurs dans la physiopathologie de l'asthme.

Asthma is often associated with a Th2-type immune response with well-known cellular and molecular actors such as eosinophils, Th2 lymphocytes and associated cytokines such as interleukin-5 or IL-4. Nevertheless, some of the asthmatic patients show clinical manifestations and characteristics that do not correspond to the current pattern of the pathophysiology of asthma. Thus, recently new cellular and molecular actors in the development of asthma have been demonstrated in animal models and in humans. Among these are components of the innate immune system such as type 2 innate lymphoid cells or adaptive immune system such as Th9 lymphocytes. At the cellular level, the role of small G proteins in asthma is also highlighted as well as the role of major cytokines like IL-17 or those derived from the epithelium. A better knowledge of the physiopathology of asthma and the taking into account of these new actors allows the identification of new therapeutic targets for different endotypes of patients.