Bactericidal Functions of Murine Alveolar Macrophages Cultured in Media Containing Serum of Mice Fed a High Fat Diet vs Mice Fed a Normal Diet
Lanka, Sree   (University of Michigan-Ann Arbor)
Mentor: Mancuso, Peter (University of Michigan)
Background Obesity and diabetes are associated with macrophage dysfunction, which may contribute to poor wound healing and susceptibility to bacterial infection. In a previous study, we demonstrated that host defense against Klebsiella pneumoniae was impaired in mice fed a high fat diet (HFD) compared with those fed a normal diet (ND). This was associated with impaired phagocytic and bactericidal function in alveolar macrophages of HFD-fed mice. 4 Methods In this study, we strove to determine the impact of media containing serum from mice fed a HFD on AM bactericidal mechanisms in vitro. The generation of reactive oxygen species (ROS) was assessed using the H2DCF method following stimulation with LPS. In addition, nitrite production was assessed using the Griess reagent. Furthermore, nitric oxide synthase (iNOS) mRNA and protein levels in macrophages were determined using immunoblot analysis. Results and Conclusion The study showed that there existed a significant reduction in phagocytosis and killing of MHS cells cultured with HFD compared with those cultured with ND. There also existed a diminished ROS and nitrite production in HFD serum AMs. However, iNOS mRNA was higher in MH-S cells cultured in HFD serum media. iNOS protein levels were higher in MH-S cells cultured with media containing serum from mice fed a ND. Future Studies In the future, we hope to examine whether serum of HFD mice or humans with obesity and diabetes contain microRNAs within exosomes that may be capable of blocking iNOS mRNA translation.