The raw data was analyzed by 2 different search engines, using shotgun proteomics, a process
by which the proteins are digested and the smaller components separated and read.
Statistically significant (p<0.05) changes of 8 proteins were achieved in the mouse liver. Of the 8
proteins, only carbamoyl-phosohate synthetase and 60kDa heat shock protein, a chaperonin,
gave significant positive log 2 fold change values, a statistical approach for detecting differential
expression. Carbomoyl-phosphate synthetase was the protein present in the highest
concentration, and up-regulation is consistent with increased amino acid breakdown resulting
from gravitational changes and/or stress associated with missions in space. Glycine N-
methyltransferase, a methyl group transferring enzyme which participates in detoxification
chemistry in the liver cells was down-regulated. Fructose-bisphosphate aldolase B levels were
also down-regulated.
Results reveal 8 of the 67 proteins showed statistical differences between flight and ground.
Some of these are linked to detoxification pathways within the liver (carbamoyl-phosohate
synthetase, glycine N-methyltransferase, S-adenosylmethionine synthetase) and some to
carbohydrate metabolism (fructose-bisphosphate aldolase B, alpha-enolase). The 60kDa heat
shock protein was up-regulated, probably because of its relation to stress. Regucalcin was
highly down-regulated possibly limiting osteoporosis. Ribonuclease UK114, also known as heat
responsive protein 12, was down regulated also possibly due to the stress of spaceflight
(Gridley 2012).
PUBLICATION(S)
Romer C, Forsman AD. The effects of the spaceflight environment on the vaginal mucin layer of
the mouse. Gravitational and Space Research. July 2015 ;3:20-28.
Latchney SE, Rivera PD, Mao XW, et al. The effect of spaceflight on mouse olfactory bulb
volume, neurogenesis, and cell death indicates the protective effect of novel environment.
Journal of Applied Physiology. June 15, 2014;116:1593-1604. doi:
10.1152/japplphysiol.01174.2013.
Zawieja DC, Mao XW, Stodieck LS, et al. Changes in mouse thymus and spleen after return from
the STS-135 mission in Space. PLOS ONE. September 19, 2013;8:e75097. doi:
10.1371/journal.pone.0075097.
Sung M, Li J, Spieker AJ, et al. Spaceflight and hind limb unloading induce similar changes in
electrical impedance characteristics of mouse gastrocnemius muscle. Journal of
Musculoskeletal and Neuronal Interactions. December 2013;13:405-411.
Forsman AD, Nier HA. The effects of spaceflight on mucin production in the mouse uterus.
Gravitational and Space Research. October 2013 ;1:20-28.
Mao XW, Pecaut MJ, Stodieck LS, et al. Spaceflight environment induces mitochondrial
oxidative damage in ocular tissue. Radiation Research. October 2013;180(4)340-350. doi:
10.1667/RR3309.1.