Nematode Muscles Project in Spaceflight Experiment

Abstract

Our previous spaceflight experiment CERISE showed that gene and protein expression levels of muscular components, cytoskeleton, and mitochondrial enzymes are altered in space flown wild-type C. elegans. To confirm and clarify whether the C. elegans muscle fibers and mitochondrial network are physically altered in response to microgravity, this Nematode Muscles project was designed with wild-type and several mutant lines with GFP expression. This investigation also studied whether microgravity could affect the insulin/ IGF-1 (Insulin-like growth factor -1) and/or TGF-β signaling by imaging DAF-16::GFP fusion protein. Wild-type and several mutants were grown in a culture bag kept under microgravity or 1G centrifuge conditions on board ISS for 4 days starting from L1 larva. All samples were fixed on board and recovered, to be analyzed on the earth. The worms did not grow well in the μG culture bag probably due to unexpected air bubbles. Therefore, DAF-16 activation observed in larval worms in μG and not in 1G may be attributed to starvation instead of μG response. In 1G samples, we could successfully find normal mitochondrial network. We also found that chemical fixation using CFA is an effective method for preservation of GFP containing C. elegans in space environment.

A Compact Imaging Platform for Conducting C. elegans Phenotypic Assays on Earth and in Spaceflight

“…Significant physiological changes occur during long-duration space travel, necessitating a fundamental understanding of the mechanisms that induce these alterations [ 53 , 54 ]. Thus, model organisms such as C. elegans have been flown to the International Space Station (ISS) several times for space-biology investigations [ 16 , 17 , 18 , 19 , 55 , 56 , 57 , 58 , 59 , 60 ]. For spaceflight missions where payload size and weight are critical considerations, C. elegans experimental payloads offer a small-form factor and a significant reduction in weight compared with vertebrates.…”

“…The numerous advantages that underscore the use of C. elegans as a genetic model on Earth also translate to its use in spaceflight as a cost-effective organism to understand the mechanisms underlying the effects of microgravity and radiation exposure on astronaut health. Indeed, C. elegans have been flown several times to the International Space Station (ISS) [ 16 , 17 , 18 , 19 , 20 ]. The conducting of animal experiments on the ISS is associated with stringent operational requirements on payload size, weight, crew time and safety [ 21 , 22 ].…”