Sick Space Flies

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Science  14 Feb 2014:
Vol. 343, Issue 6172, pp. 710
DOI: 10.1126/science.343.6172.710-a

A concern regarding manned long-term space missions is that changes in gravitational force compromise the human immune system, but the underlying cellular and molecular reasons have not been clear. Taylor et al. studied innate immunity in Drosophila melanogaster that traveled aboard Space Shuttle Discovery in 2006. Flies reared in space were compared to flies that underwent development on Earth. Upon the return of the space-reared flies to Earth, both groups of flies were subjected to bacterial (Escherichia coli) or fungal (Beauveria bassiana) infections, and their gene expression profiles were examined. Genes associated with Toll receptor–mediated immune responses to fungal infection were activated only in the Earth flies. The expression of specific antimicrobial peptides also failed in the space flies. Other mechanisms, such as the Imd signaling pathway response to bacterial infection, were not affected in space flies. The space flies exhibited increased expression of heat shock response genes, a subset of stress response genes that are activated to manage aberrant protein folding. The authors suggest that microgravity may alter the folding and stability of proteins, which triggers the deployment of heat shock proteins that in turn, may interfere with the Toll receptor signaling pathway.

PLOS One 9, e86485 (2014).

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