Proteomic Study On The Synergetic Biological Effects Of Space Radiation And Microgravity By Using C.elegans

Space radiation and microgravity are main factors of spaceflight which could cause effects on organism.For further elucidate the single factor effects of radiation or microgravity and the synergetic factor effects of them,the wild-type strain(Bristol N2)of Caenorhabditis elegans(C.elegans)in dauer larvae were treated by ground simulated radiation and/or simulated microgravity.The locomotory capacity assay and proteomic analysis by LC-MS/MS were processed after the recovery of dauer larvae to L4 larvae,proteome profiles were compared between three factors for analyzing protein regulation pathways affected by radiation and/or microgravity.Locomotory capacity assay showed that the N2 nematodes were susceptible to simulated microgravity but not to simulation radiations.The synergetic factor also enhanced the locomotory capacity but not as significant as the single factor of microgravity.A protein expression profile containing 3190 proteins of c.elegans were established using lable free LC-MS/MS analysis.These proteins mainly participate in the biological processes of life activities,locomotion,development,metabolism and reproduction.Principal component analysis and cluster analysis of differentially expressed proteins showed that single factor of radiation or microgravity,synergetic factor of radiation and microgravity could all change protein expression profiles of N2 nematodes.But compared with the control,radiation caused minimum alteration,microgravity secondly;synergetic factor caused the biggest change in protein expression profiles.It indicated that microgravity and radiation caused stronger synergistic effect.Distribution of biological process by Gene Ontology enrichment analysis indicated that gene expression regulation related pathways were wildly changed by all of the treatments.Single factor of radiation mainly led to disorders of cell mitotic process,single factor of microgravity mainly caused changes of regulation of programmed cell death and energy metabolism,synergetic factor of primarily changed the process of nucleotide and base metabolism during DNA and RNA biosynthesis.These results suggested that the single factor of radiation or microgravity and the synergetic factor of radiation and microgravity could all affect biological effects,but the microgravity single factor is the main reason for the biological effects induced by spaceflight.The functional proteomic results further confirmed microgravity enhanced the radiation stress effect on C.elegans,which launched the biological function of stress-resistance.