Impact of altered gravity on the ROS-signalling in macrophages (P1293)

Abstract

Abstract Astronauts suffer from a higher susceptibility to infections during spaceflights. Different stressors could lead to a diminished immune defense. Macrophages present the first line of defense of the innate immune system. Their main challenge is the recognition, engulfment and destruction of pathogenic bacteria, viruses and dead cells. The killing of bacteria is accomplished by the production of Reactive Oxygen Species (ROS) during oxidative burst. We investigated the effects of altered gravity on the pattern recognition and ROS production of macrophages. Our results show that real microgravity (parabolic flight), simulated microgravity (2D fast-rotating clinostat) as well as hypergravity (centrifuge) alter the production of ROS after stimulation of cell surface receptors Dectin, TLR2/6, complement and Fcγ. We also find that phosphorylation of the tyrosine kinase Syk, an essential link between pattern recognition, cytoskeleton and ROS production, is sensitive to microgravity. We can conclude that both microgravity and hypergravity cause very fast changes in ROS production, characterising the oxidative burst as a gravisensitive processes. Altered gravity might have impact on the interaction of different pattern recognition signalling pathways, which are crucial for the bacteria clearance in terms of ROS production. Therefore, the study of ROS signalling under altered gravity is not only of interest for humans in space, but also for human health on Earth.