GSE131954
Spaceflight causes changes in gene expression, photoreceptor integrity, and oxidative stress-related damage in the murine retina
Purpose:The purpose of this study was to determine whether the spaceflight environment induces oxidative damage on ocular structure and how gene expression profiles change during spaceflight. Methods: RNA sequencing, immunofluorescence, and microCT assays were performed on two groups of mice to assess the effects of spaceflight on the mammalian retina. Ten week old adult C57BL/6 mice was flown aboard the ISS for 35 days and returned to Earth alive. Ground control mice were maintained on Earth in identical flight hardware. Within 38 (+/-4) hours of splashdown, mice were euthanized and ocular tissues were collected for analysis. Results:RNA sequencing detected 600 differentially expressed genes in spaceflight retina. This set of differentially expressed genes is enriched for genes related to visual perception, the phototransduction pathway, and numerous retina and photoreceptor phenotype categories. Eleven of the differentially expressed genes are associated with the disease retinitis pigmentosa, a retinal disease characterized by dystrophy of the rods and cones of the photoreceptor layer. Analysis of differentially expressed transcription factors indicate changes in chromatin structure, offering clues to the causes of the phenotypic changes observed. Additionally, immunofluorescence assays showed degradation of cone photoreceptors and increased oxidative stress in the retina. Retinal thickness, as well as thickness of the retinal pigment epithelium and choroid layers, were significantly reduced after spaceflight. Conclusions: These results indicate that retinal performance may decrease over extended periods of spaceflight and cause visual impairment. Overall design: Retinal RNA-Seq libraries of ten week old adult C57BL/6 mice were constructed (Ovation® Mouse RNA-Seq System; Nugen) and sequencing performed on  Illumina HiSeq 4000