Simulated microgravity effects impair macrophage phagocytosis by regulating cytoskeleton-associated proteins

Abstract

Abstract Many studies have shown that microgravity can cause damage to the immune system of astronauts, posing serious health risks to astronauts in space flight. In particular, macrophages, as an important target for studying the effects of microgravity on immunity, its regulation mechanism by microgravity is still unclear. In this study, Random Positioning Machines (RPM) and Rotary Cell Culture System (RCCS) were employed for understanding the effect of simulated microgravity (SMG) effects on the immune function of macrophages in 48 h. Firstly, under simulated microgravity conditions, the cells atrophied, the pseudopodia on the surface were reduced, and the phagocytosis and proliferation of macrophages were significantly dropped. Secondly, SMG attenuated the immune response of macrophages by reducing the expression of phagocytosis-related receptors on the surface of macrophages, which may be the main reason for the phagocytosis decline. Finally, by transcriptome analysis and molecular biology validation, the results suggest that SMG also leads to a decreased expression of cytoskeleton-related proteins, which may be indicate an alternative mechanism for SMG affecting the immune response of macrophages. Our findings can provide guidance on immune damage caused by microgravity and help protect the health of astronauts.