Protein expression changes caused by spaceflight as measured for 18 Russian cosmonauts

Area of Science:

• Proteomics
• Space Physiology
• Systems Biology

Background:

• Spaceflight significantly impacts human physiology, but underlying molecular mechanisms are not fully understood.
• Understanding proteomic changes is crucial for astronaut health during long-duration space missions.

Purpose of the Study:

• To investigate alterations in the human plasma proteome during and after long-duration space travel.
• To identify specific proteins and biological pathways affected by spaceflight.

Main Methods:

• Quantified 125 plasma proteins in 18 Russian cosmonauts using targeted mass spectrometry and multiple reaction monitoring.
• Employed stable isotope-labeled standards for accurate protein quantitation across a wide concentration range.
• Utilized linear discriminant function analysis to categorize protein concentration changes.

Main Results:

• Identified three distinct protein groups based on post-flight recovery: stable, slow-recovering, and rapid-recovering.
• Nearly all affected proteins were linked to pathways regulating protease activity, natural immunity, lipid metabolism, coagulation, and extracellular matrix metabolism.

Conclusions:

• Spaceflight induces significant, yet distinct, changes in the human proteome.
• These proteomic shifts are associated with critical physiological processes, offering insights into spaceflight adaptation and recovery.