Alterations of C. elegans muscle fibers by microgravity (Nematode Muscles) - 09.17.14
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Astronauts frequently experience weakened muscles, reduced bone density and changes in metabolism, which can negatively affect their health and performance. Alterations of C. elegans muscle fibers by microgravity (Nematode Muscles) uses a model organism, a nematode worm called C. elegans, to clarify how and why these changes take place in microgravity. Studying worms exposed to both microgravity, and gravity-like conditions in a centrifuge, could help scientists understand the molecular mechanisms responsible for muscle atrophy and other spaceflight-induced changes.
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OpNom Nematode Muscles (TBD)
Space Environment Utilization Center, Japan Aerospace Exploration Agency, Tsukuba, , Japan
Sponsoring Space Agency
Japan Aerospace Exploration Agency (JAXA)
ISS Expedition Duration
September 2014 - March 2015
Previous ISS Missions
Spaceflight appears to induce metabolic changes and muscle atrophy in crewmembers, many of which are suggested to have detrimental consequences for crew heath and performance. To overcome this obstacle, it is important to understand the molecular mechanisms regulating spaceflight-induced alterations.
This investigation seeks to clarify whether C. elegans muscle fibers and cytoskeleton networks are altered in response to microgravity. The investigation also studies whether insulin/IGF-1 (Insulin-like growth factor -1) signaling is sufficient to account for the alterations using Green Fluorescence Protein (GFP) imaging. Wild-type and certain mutants are cultured in both microgravity and 1G centrifuge conditions on board for 4 days starting from each L1 larva. All samples are fixed on board, and recovered for analysis on earth.
The results will be utilized for combating deleterious spaceflight-induced adaptations, for maintained crew health and mission performance in future.
We successfully confirmed the effectiveness of RNAi technology under microgravity in the C. elegans RNA interference space experiment (CERISE) (PLoS One 2011, 6, e204591). We also found that the expression levels of muscle and cytoskeleton proteins were repressed in the spaceflown C. elegans. Moreover, certain gene expressions involved in energy metabolism were repressed and oppositely sirtuin gene induced by caloric restriction was upregulated under microgravity. These findings indicate that spaceflown C. elegans 1) have reduced muscle and cytoskeletal protein concentration, and 2) demonstrate altered mitochondrial energy metabolism towards a saving energy mode.
In this investigation, we clarify whether C. elegans muscle fibers and cytoskeleton networks in each cell and individual were altered in response to microgravity. We also study whether insulin/IGF-1 signaling is sufficient to account for the muscular, cytoskeletal and metabolic changes using GFP imaging system. As summary of space flight experiment, wild-type and certain mutants are cultured in both microgravity and 1G centrifuge conditions on board for 4 days starting from each L1 larva. All samples are fixed on board and recovered, and analyzed on the earth. The results will help to provide clues as to the effects of microgravity on muscle atrophy in humans during long-duration space flight.
By studying muscle and metabolism changes in a small worm, scientists may be able to understand similar physical changes that take place in the human body during spaceflight. Worms will be grown from larvae samples and returned to Earth for later study. Examining muscle fibers and cellular scaffolding in the worms will help researchers understand muscle atrophy and bone density loss in crewmembers.
Patients on prolonged bed rest experience muscle atrophy, bone density loss and changes in metabolism, similar to the effects of spaceflight. Understanding the molecular changes that take place in microgravity could help researchers develop treatments or therapies to counteract the physical changes associated with aging and bed rest.
Launch Orientation: Not required.
Start incubation: Start incubation within 10 days after the turning over of the samples, so that Nemato Muscles can be implemented together with Space Aging.
Sampling timing: Sample fixation should be achieved at 4 (-0/+1) days after starting incubation.
Cold Stowage requirement: Nematodes and E.coli should be kept cooled at +4°C (+3-+8°C) before starting incubation. Chemical Fixation Apparatus should be kept cooled at +2°C (+0.5-+6°C) before and after fixation.
Chemical Fixation Apparatus should be recovered in six months.
Nemato Muscles is to be implemented together with Space Aging, another JAXA experiment.
Activity 1: Using 10 syringes, inject 10 nematode samples to 10 chambers which contain E.coli. Mix nematode and E.coli samples.
Activity 3: After 4 days of incubation, fix 4 samples (2 from 1G, 2 from micro G) with paraformaldehyde using CFK, and stow in MELFI at 2C.
Activity 4: At the same time as the Activity 2, relocate the rest of 6 chambers into CBEF (2 chambers from micro G to 1G, the rest remain in the same G) and continue incubation for 1 day at 20°C.
Activity 5: Fix 6 samples with paraformaldehyde using CFK, and stow in MELFI at 2C.