Data from: Cytoskeletal stability and metabolic alterations in primary human macrophages in long-term microgravity

The immune system is one of the most affected systems of the human body
during space flight. The cells of the immune system are exceptionally
sensitive to microgravity. Thus, serious concerns arise, whether space
flight associated weakening of the immune system ultimately precludes the
expansion of human presence beyond the Earth's orbit. For human space
flight, it is an urgent need to understand the cellular and molecular
mechanisms by which altered gravity influences and changes the functions
of immune cells. The CELLBOX-PRIME (= CellBox-Primary Human Macrophages in
Microgravity Environment) experiment investigated for the first time
microgravity-associated long-term alterations in primary human
macrophages, one of the most important effector cells of the immune
system. The experiment was conducted in the U.S. National Laboratory on
board of the International Space Station ISS using the NanoRacks
laboratory and Biorack type I standard CELLBOX EUE type IV containers.
Upload and download were performed with the SpaceX CRS-3 and the Dragon
spaceship on April 18th, 2014 / May 18th, 2014. Surprisingly, primary
human macrophages exhibited neither quantitative nor structural changes of
the actin and vimentin cytoskeleton after 11 days in microgravity when
compared to 1g controls. Neither CD18 or CD14 surface expression were
altered in microgravity, however ICAM-1 expression was reduced. The
analysis of 74 metabolites in the cell culture supernatant by GC-TOF-MS,
revealed eight metabolites with significantly different quantities when
compared to 1g controls. In particular, the significant increase of free
fucose in the cell culture supernatant was associated with a significant
decrease of cell surface-bound fucose. The reduced ICAM-1 expression and
the loss of cell surface-bound fucose may contribute to functional
impairments, e.g. the activation of T cells, migration and activation of
the innate immune response. We assume that the surprisingly small and
non-significant cytoskeletal alterations represent a stable "steady
state" after adaptive processes are initiated in the new microgravity
environment. Due to the utmost importance of the human macrophage system
for the elimination of pathogens and the clearance of apoptotic cells, its
apparent robustness to a low gravity environment is crucial for human
health and performance during long-term space missions.