Research Summary: The Effectiveness of RNAi in Caenorhabditis elegans Is Maintained during Spaceflight

ABSTRACT

Background

Overcoming spaceflight-induced (patho)physiologic adaptations is a major
challenge preventing long-term deep space exploration. RNA interference
(RNAi) has emerged as a promising therapeutic for combating diseases on
Earth; however the efficacy of RNAi in space is currently unknown.


Methods

Caenorhabditis elegans were prepared in liquid media on
Earth using standard techniques and treated acutely with RNAi or a vector
control upon arrival in Low Earth Orbit. After culturing during 4 and 8 d
spaceflight, experiments were stopped by freezing at −80°C until
analysis by mRNA and microRNA array chips, microscopy and Western blot on
return to Earth. Ground controls (GC) on Earth were simultaneously grown
under identical conditions.


Results

After 8 d spaceflight, mRNA expression levels of components of the RNAi
machinery were not different from that in GC (e.g., Dicer, Argonaute, Piwi;
P>0.05). The expression of 228 microRNAs, of the 232
analysed, were also unaffected during 4 and 8 d spaceflight
(P>0.05). In spaceflight, RNAi against green
fluorescent protein (gfp) reduced chromosomal
gfp expression in gonad tissue, which was not different
from GC. RNAi against rbx-1 also induced abnormal
chromosome segregation in the gonad during spaceflight as on Earth. Finally,
culture in RNAi against lysosomal cathepsins prevented degradation of the
muscle-specific α-actin protein in both spaceflight and GC
conditions.


Conclusions

Treatment with RNAi works as effectively in the space environment as on Earth
within multiple tissues, suggesting RNAi may provide an effective tool for
combating spaceflight-induced pathologies aboard future long-duration space
missions. Furthermore, this is the first demonstration that RNAi can be
utilised to block muscle protein degradation, both on Earth and in
space.

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Publisher: Public Library of Science

Date Published: 1-June-2011

Author(s): Etheridge T., Nemoto K., Hashizume T., Mori C., Sugimoto T., Suzuki H., Fukui K., Yamazaki T., Higashibata A., Szewczyk N., Higashitani A.

Link: https://doi.org/10.1371/journal.pone.0020459

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