Background Bronchial asthma is a chronic disease characterized by inflammation, obstruction, and hyperresponsiveness of the airways. There is currently no curative therapy for asthma. Type 2 helper T cell response plays a critical role in the pathogenesis of the disease. Protein S is a glycoprotein endowed with anticoagulant, anti‐inflammatory, and anti‐apoptotic properties. Whether protein S can suppress bronchial asthma and be useful for its therapy is unknown. Methods To address this question here we compared the development of allergen‐associated bronchial asthma between wild type and protein S‐overexpressing transgenic mice. Mice were sensitized and challenged with ovalbumin. We also evaluated the circulating levels of total and active protein S in patients with bronchial asthma and healthy controls. Results The circulating level of total protein S and of its active form was significantly decreased in patients with bronchial asthma compared to controls. Allergic protein S transgenic mice showed a significant reduction of airway hyperresponsiveness, lung tissue inflammatory cell infiltration, lung levels of Th2 cytokines and IgE compared to their wild‐type counterparts. Administration of exogenous human protein S also decreased airway hyperresponsiveness and Th2‐mediated lung inflammation in allergic wild‐type mice compared with their untreated mouse counterparts. Human protein S significantly shifted the Th1/Th2 balance to Th1 and promoted the secretion of Th1 cytokines (IL‐12, tumor necrosis factor‐α) from dendritic cells. Conclusions These observations suggest the strong protective activity of protein S against the development of allergic bronchial asthma implicating its potential usefulness for the disease treatment.
Inflammation, reversible obstruction, and hyperresponsiveness of the airways are characteristic findings of bronchial asthma. Several evidence has demonstrated the involvement of matrix metalloproteinase-2 in allergic airway inflammation. Matrix metalloproteinase-2 may promote aberrant tissue remodeling in late stages of allergic airway inflammation. However, whether matrix metalloproteinase-2 is detrimental or protective in early stages of allergic airway inflammation remains unclear. To evaluate this here we compared the severity of allergic bronchial asthma between mice overexpressing human matrix metalloproteinase-2 and wild type mice. After sensitization and challenge with an allergen, mice overexpressing the human matrix metalloproteinase-2 showed a significant reduction in airway hyperresponsiveness and in the expression of Th2 cytokines and IgE compared to their wild type counterparts. An inhibitor of matrix metalloproteinases abolished this beneficial effect of human matrix metalloproteinase-2 overexpression. Allergen-sensitized and challenged human matrix metalloproteinase-2 transgenic mice had enhanced percentage of M1 macrophages with increased expression of inducible nitric oxide synthase and STAT1 activation in the lungs compared to their wild type counterparts. There was no difference in the percentage of regulatory T cells between mouse groups. The results of this study showed that matrix metalloproteinase-2 is protective in allergic bronchial asthma by promoting polarization of macrophages to M1 phenotype.
Acute lung injury is a fatal disease characterized by inflammatory cell infiltration, alveolar-capillary barrier disruption, protein-rich edema, and impairment of gas exchange. Protein S is a vitamin K-dependent glycoprotein that exerts anticoagulant, immunomodulatory, anti-inflammatory, anti-apoptotic, and neuroprotective effects. The aim of this study was to evaluate whether human protein S inhibits cell apoptosis in acute lung injury. Acute lung injury in human protein S transgenic and wild-type mice was induced by intratracheal instillation of lipopolysaccharide. The effect of human protein S on apoptosis of lung tissue cells was evaluated by Western blotting. Inflammatory cell infiltration, alveolar wall thickening, myeloperoxidase activity, and the expression of inflammatory cytokines were reduced in human protein S transgenic mice compared to the wild-type mice after lipopolysaccharide instillation. Apoptotic cells and caspase-3 activity were reduced while phosphorylation of extracellular signal-regulated kinase was enhanced in the lung tissue from human protein S transgenic mice compared to wild-type mice after lipopolysaccharide instillation. The results of this study suggest that human protein S is protective in lipopolysaccharide-induced acute lung injury by inhibiting apoptosis of lung cells.
Background. Case. Conclusion.
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