Assessment of Cyanobacterial LPS-mediated Asthma Exacerbation in a mouse model 2361

Abstract Description While many asthmatic responses are pharmacologically controlled through inhaled steroids, an increasing percentage of asthma is steroid-resistant. This steroid resistant asthma demonstrates a mixed infiltration of both eosinophils and neutrophils. The recruitment of neutrophils to the lung can be induced by environmental factors, such as aerosolized LPS. Our laboratory studies how aerosolized LPS from environmental cyanobacteria near fresh water sources impacts lung inflammation. In this study, we confirm that LPS from the cyanobacteria Brasilonema sp., induces neutrophil influx and murine airway inflammation in a TLR4-dependent manner. We then asked if Brasilonema sp. LPS induces a steroid-resistant, mixed eosinophil/neutrophil phenotype in an OVA-dependent model of asthma. For these studies, mice were sensitized to OVA and airway inflammation was induced by OVA intranasal re-exposure on days 14-16 post sensitization. To determine if Brasilonema sp. LPS influenced the phenotype of infiltrating cells, mice were exposed intranasally to Brasilonema sp. LPS on days 21-23 post initial OVA sensitization. Our data indicate that Brasilonema sp. LPS did not significantly exacerbate OVA-induced lung inflammation as determined by lung neutrophil and eosinophil infiltration and cytokine production in these mice. These data suggest that while cyanobacteria LPS induces lung inflammation, it did not influence the phenotype of infiltrating cells induced by ovalbumin in our current model. Funding Sources These studies were supported by intramural funds at Midwestern University and the Midwestern University Core Facilities, Downers Grove IL. Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)