Hepatic proteome analysis in mice following 90 days of spaceflight

Abstract

Long‐term exposure to altered gravitational environments leads to altered intermediary metabolism and concomitant changes in body adiposity. It is unclear to what extent changes in hepatic function might underlie these metabolic shifts. Using proteomic technology, we examined liver protein profiles in mice exposed to long‐term microgravity via spaceflight. The analysis was performed on livers obtained from male mice (n=3) that were exposed to 90 days of microgravity on the International Space Station (ISS). Control livers were obtained from mice (also n=3/group) housed in either simulated ISS flight cages or standard vivarium cages on Earth. Liver proteins were extracted, separated on a 1‐D gel, trypsin digested and analyzed by LC MS/MS. Proteins were searched and validated with X! tandem and Scaffold Software. ANOVA was used to determine significant differences in expression (spectral counts) between groups. Roughly 4,000 proteins with a 7.7% protein and 0.1% peptide false discovery rate were identified, of which approximately 500 demonstrated significant changes (p<0.05). Of these, approximately 250 proteins were uniquely different between flight and ground groups, including a number of proteins involved in fatty acid metabolism. This work was supported in part by NASA Grant NNX08AR88G (CAF).