9:20 AM - 9:45 AM
[HCG29-03] Establishment of food self-sufficiency system for functional space foods to support manned space activities
★Invited Papers
Keywords:Functional Space Foods, Disuse muscle atrophy, Plant factory
Previous studies have shown that ubiquitin ligase Cbl-b, of which expression is increased by microgravity, induced IRS-1 ubiquitination and degradation, resulting in impaired IGF-1 signal and muscular atrophy. However, it remains unclear how cells sense weightless stress and enhance Cbl-b expression. Therefore, to clarify the mechanism of gravity sensing by these cells, we conducted “Myolab” and “Cell Mechanosensing” space experiments, and 3D-Clinorotation, which is a simulated microgravity culture device on the ground. First, in the Myolab space experiment, we performed metabolome analysis of space samples cultured under microgravity conditions for a week. Then we found that microgravity accumulated oxidative stress in cells and changed the expression of proteins localized in mitochondria related to energy metabolism. It was also found that the oxidative stress regulates the expression of ubiquitin ligase Cbl-b via Egr1 / 2 and ERK1 / 2 pathways.
Therefore, we considered ubiquitin ligase Cbl-b and oxidative stress as targets for functional foods that can prevent muscle atrophy due to weightlessness.
1) Soy protein (anti-ubiquitinating effect)
We discovered a DG (p) YMP peptide (named Cblin peptide) that has an inhibitory activity on the binding of IRS-1, which is the target molecule of ubiquitin ligase Cbl-b. Furthermore, it was found that the soy protein glycinin has a similar sequence. These suppressed the ubiquitination of IRS-1 by Cbl-b and increased muscle mass in in vitro and in vivo experiments. In addition, the soy protein-added diet was also effective in suppressing muscle weakness in bedridden patients.
2) Polyphenol (antioxidant effect)
Polyphenols are attracting attention as a dietary ingredient that can reduce antioxidant stress. Antioxidant nutrients such as soy isoflavone and quercetin have been shown to suppress muscular atrophy due to tail suspension.
Because of the usefulness of these functional ingredients of soybeans for such muscle atrophy, we are advocating the construction of a plant factory that can make soybeans self-sufficient in the space environment.