An inactivated Pseudomonas aeruginosa medicament inhibits airway allergic inflammation and improves epithelial functions

Abstract

The features of asthma are airway hyperresponsiveness (AHR), excess production of Th2 cytokines, and eosinophil accumulation in the lungs. To investigate the antiasthmatic potential of an inactivated Pseudomonas aeruginosa medicament (PPA), as well as the underlying mechanism involved, we studied the effects of PPA on airway and epithelial functions. Airway resistance, cell enumeration, and IL-4, IFN-γ, and IL-17 secretion in bronchoalveolar lavage fluid were assayed on an OVA-sensitized AHR animal model. Flow cytometry was used to observe the effects of PPA on cell proliferation, real-time PCR was used to test the expressions of toll like receptor 4 and 5, and Th17 signal molecules Act1, NF-kB negative regulator A20, and western blot were used to detect NF-kB expression on cultured human bronchial epithelial cells (BECs). PPA-treated animals had suppressed airway resistance, eosinophil and lymphocytes infiltration, and IL-4 and IL-17 secretion. PPA can stimulate toll-like receptor-4 and 5 expressions, promote cell proliferation in normal and OVA-treated BECs, significantly decrease Act1 and NF-kB, and increase A20 expression in BECs treated by OVA. Our data suggest the therapeutic mechanism by which PPA effectively treats allergic inflammation on reductions of airway responsiveness, eosinophil infiltration, IL-4 and IL-17 secretion, and improvements of epithelial functions.