Re-adaption on Earth after Spaceflights Affects the Mouse Liver Proteome

Area of Science:

• * Space biology and astrobiology
• * Hepatic metabolism and toxicology

Background:

• * Prolonged spaceflight exposes astronauts to harsh conditions like microgravity and radiation, impacting hepatic (liver) metabolism.
• * Understanding these metabolic alterations is crucial for astronaut health during long-duration missions.

Purpose of the Study:

• * To analyze changes in liver metabolic pathways in mice after 30 days of spaceflight.
• * To investigate the effects of a seven-day re-adaptation period on these metabolic changes.

Main Methods:

• * Proteomic profiling of mouse livers using shotgun mass spectrometry.
• * Label-free quantification with MaxQuant software and statistical analysis (ANOVA).

Main Results:

• * Identified 1,086 proteins, with 218 up-regulated and 224 down-regulated post-flight.
• * Re-adaptation increased amino acid metabolism proteins, suggesting enhanced gluconeogenesis.
• * Peroxisome proliferator-activated receptor pathway proteins returned to normal levels, indicating reduced liver lipotoxicity.

Conclusions:

• * Seven days of re-adaptation on Earth can restore liver metabolic functions, including bile acid secretion and pharmacological response.
• * Spaceflight-induced liver lipotoxicity diminishes post-adaptation.
• * Altered gluconeogenesis necessitates monitoring glucose uptake in returning astronauts.