Gene expression profiling for spaceflight induced-neuroinflammation in the mouse brain

The health risk from spaceflight-induced neuronal damage and potential adverse neurovascular effects is a chief concern. More recently, it has been proposed that neuroinflammatory response plays an important role in the neurovascular remodeling in the brain after stress. The goal of the present study was to characterize changes in the gene expression of neuroinflammation panel for inflammation, neuronal function, metabolism and stress in mouse brain tissue. Ten-week old male C57BL/6 mice were launched to the International Space Station (ISS) on Space-X 12 for a 35-day mission. Within 38+4 hours of splashdown, mice were returned to Earth alive. Brain tissues were collected for analysis. Habitat ground control (GC) mice were maintained on Earth in flight hardware cages. A novel digital color-coded barcode counting technology (NanoStringTM) was used to evaluate gene expression profiles in the spaceflight mouse brain. The Neuroinflammation panel includes 757 genes covering the core pathways and processes that define neuroimmune interactions. A set of 54 differently expressed genes (p<0.05) significantly segregates the GC group from flight (FLT) group. Many pathways associated with cellular stress, inflammation, apoptosis, and metabolism were significantly altered by flight conditions. Genes supporting neuronal synaptic signaling and migration were significantly downregulated in FLT compared to the GC mice. A decrease in the expression of genes important for oligodendrocyte differentiation and myelin sheath maintenance was observed. Moreover, mRNA expression of many genes related to antiviral signaling, reactive oxygen species (ROS) generation, and bacterial immune response were significantly downregulated. These data indicate that neuroinflammation and altered immune reactions may be closely associate with spaceflight-induced stress response and have an impact on the neuronal function that may result in chronic neuroinflammation and late neurodegeneration. A total of 12 frozen right caudal half hemispheres containing mid- and hindbrain from GC and FLT mice (n=6 per group), were used for analysis