An Epigenetic Trigger for Induction of Genomic Plasticity Following Exposure to Space Environment: Mission SpaceX CRS-19 RRR-1 [RNA-seq]

Genomic plasticity helps adapt to extreme environmental conditions. We tested the hypothesis that exposure to space environment (ESE) impacts the epigenome as marked by DNA hypomethylation to induce genomic plasticity in responders. Murine skin samples from the Rodent Research Reference Mission-1 were procured from the International Space Station (ISS) National Lab. Targeted RNA sequencing to test differential gene expression between the skin of ESE versus ground controls revealed upregulation of VEGF mediated angiogenesis pathways secondary to promoter hypomethylation in responder ESE cohort. Methylome sequencing identified ESE-sensitive candidate hypomethylated genes including developmental angiogenic genes Araf, VegfbandVegfr1. Based on differentially expressed genes, the angiogenesis biofunction was enriched in responders compared to non-responders. The induction of genomic plasticity in response to ESE, as reported herein, may be viewed as a mark of biological resilience that is evident in a minority of organisms, responders but not in non-responders, exposed to the same stressor. Inducible genomic plasticity may be implicated in natural resilience to ESE.