Microgravity elicits reproducible alterations in cytoskeletal and metabolic gene and protein expression in space-flown Caenorhabditis elegans
Nature Publishing Group
Although muscle atrophy is a serious problem during spaceflight, little is known about the sequence of molecular events leading to atrophy in response to microgravity. We carried out a spaceflight experiment using Caenorhabditis elegans onboard the Japanese Experiment Module of the International Space Station. Worms were synchronously cultured in liquid media with bacterial food for 4 days under microgravity or on a 1-G centrifuge. Worms were visually observed for health and movement and then frozen. Upon return, we analyzed global gene and protein expression using DNA microarrays and mass spectrometry. Body length and fat accumulation were also analyzed. We found that in worms grown from the L1 larval stage to adulthood under microgravity, both gene and protein expression levels for muscular thick filaments, cytoskeletal elements, and mitochondrial metabolic enzymes decreased relative to parallel cultures on the 1-G centrifuge (95% confidence interval (P⩽0.05)). In addition, altered movement and decreased body length and fat accumulation were observed in the microgravity-cultured worms relative to the 1-G cultured worms. These results suggest protein expression changes that may account for the progressive muscular atrophy observed in astronauts.
We are grateful to the entire crew of the CERISE for their work on STS-129, STS-130, and the ISS. The CERISE was organized with the support of the JAXA. This experiment was supported by the Cell Biology Experiment Project conducted by the Institute of Space and Astronautical Science in JAXA, and was funded in part by JSPS KAKENHI Grant Numbers 26506029, 15H05937, the Medical Research Council UK (G0801271), and National Institutes of Health (NIH NIAMS ARO54342).
This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/npjmgrav.2015.22
NPJ Microgravity, 2016, 2, Article number 15022