Immune and microRNA Differentials following Simulated Deep Spaceflight

Spaceflight can cause immune system dysfunction in astronauts with little understanding of immune outcomes in deep space. This study assessed immune responses in mice following simulated deep spaceflight, along with retrospective data from astronauts on the International Space Station (ISS). We simulated microgravity using the hindlimb unloaded mouse model alone or in combination with the newly developed simulated galactic cosmic rays or solar particle events irradiation at NASA’s Space Radiation Laboratory. Immune differentials revealed unique immune diversity following each experimental platform, suggesting consequences for deep spaceflight. Furthermore, circulating plasma microRNA sequencing analysis revealed immune system dysregulation. An ISS astronaut cohort showed elevated inflammation during low-Earth orbit missions, which supports our simulated ground experiments. Herein, distinct circulating immune biomarkers are defined by irradiation type, coupled to simulated microgravity, which can be promising targets for countermeasure developments and programmatic queries.