|Short-term spaceflight does not hinder RNA interference efficacy in roundworms, and may be a means of preventing protein muscle degradation in humans during long-term space missions.|
Typical drugs won't work. Radiation in space limits their shelf life.
RNA interference may be an alternative solution. Here, certain small RNA molecules can regulate (enhance or suppress) the activity of other RNA molecules, thereby controlling protein production.
This realm of medicine is often dangerous as currently practiced, because scientists haven't uncovered all the details of how it works. However, RNA interference does show widespread promise, e.g. as antiviral agents.
Nathaniel Szewczyk (University of Nottingham, UK), Atsushi Higashitani (Tohoku University, Japan), and coworkers have demonstrated the efficacy of RNA interference against roundworms in space. Their research suggests a possible role for RNA interference therapy in humans during long-term space missions.
This research is complimentary to that focused on detecting photosynthesis on other worlds, and using roundworms to detect explosives.
Roundworms in space.
The scientists first grew Caenorhabditis elegans (roundworm) larvae in nutrient-deprived media on Earth. They then shipped them into space aboard the International Space Station, where they were given food in microgravity to begin the experiment.
The roundworms were frozen at -80°C after either four or eight days before shipment back to Earth for further study. Additional experiments were also performed on Earth using an orbital environmental simulator, which adjusts carbon dioxide, oxygen, and humidity levels, but neither radiation nor gravity levels.
Extensive microarray analysis (after eight days in space) suggested normal gene activity relevant to RNA interference. The RNA interference agents themselves were also largely unaffected; only 4 out of 232 of these molecules exhibited a greater than 20% change in activity after either a trip in space or the orbital environmental simulator.
Direct visualization of RNA interference activity was observed after four days of spaceflight using optical microscopy. RNA interference was still effective against green fluorescent protein, and cell division was still hindered as intended.
Furthermore, a Western blot analysis indicated that RNA interference protects against genetically engineered muscle degradation. RNA interference efficacy for preventing α-actin (muscle protein) from degradation by cathepsin proteins within the lysosome subcellular compartment was retained after four days of spaceflight.
This research is a long way from preventing physiological harm to humans during long spaceflights. However, given the widespread use of roundworms in the molecular biology community to study RNA interference, they're suitable organisms for carrying out further research towards this long-term goal of human health preservation in space.
NOTE: The scientists' research was funded by the Ministry of Education, Culture, Sports, Science, and Technology of Japan; the Japan Society for the Promotion of Science; the Japan Space Forum; the Medical Research Council UK; and the National Institutes of Health.
Timothy Etheridge, Kanako Nemoto, Toko Hashizume, Chihiro Mori, Tomoko Sugimoto, Hiromi Suzuki, Keiji Fukui, Takashi Yamazaki, Akira Higashibata, Nathaniel J. Szewczyk, & Atsushi Higashitani (2011). The Effectiveness of RNAi in Caenorhabditis elegans Is Maintained during Spaceflight PLoS ONE, 6 (6) : 10.1371/journal.pone.0020459