Gene expression levels were determined in 3rd instar and adult Drosophila melanogaster reared during spaceflight to elucidate the genetic and molecular mechanisms underpinning the effects of microgravity on the immune system. The goal was to validate the Drosophila model for understanding alterations of innate immune responses in humans due to spaceflight. Five containers of flies with ten female and five male fruit flies in each container were housed and bred on the space shuttle (average orbit altitude of 330.35 km) for 12 days and 18.5 hours with a new generation reared in microgravity. RNA was extracted on the day of shuttle landing from whole body animals (3rd instar larvae and adults) hybridized to Drosophila 2.0 Affymetrix genome arrays and the expression level of all genes was normalized against the gene expression level from the corresponding developmental stage animals raised on ground. Spaceflight altered the expression of larval genes involved in the maturation of plasmatocytes (macrophages) and their phagocytic response as well as the level of constitutive expression of pattern recognition receptors and opsonins that specifically recognize bacteria and of lysozymes antimicrobial peptide pathway and immune stress genes hallmarks of humoral immunity. Larval microarrays (FL 6 samples) are based on RNA extracted from 6 independent sets of 50 mid 3rd instar larvae reared in microgravity and collected on the day of landing after 12 days and 18.5 hours on the space shuttle and the same number of control larvae raised on ground (GL 6 samples). Adults microarrays (F1 3 samples) are based on RNA from 3 sets of 20 adult females each that emerged during spaceflight and within 4 hours of landing and the same number of adult females from the corresponding ground control containers (G1 3 samples).

Astronauts are exposed to a unique combination of stressors during spaceflight, which leads to alterations in their physiology and potentially increases their susceptibility to infectious pathogens. Here we report the first microarray evaluation of any astronaut tissue sample, specifically whole blood, before and after spaceflight using an array comprising 234 well-characterized stress response genes. Differentially regulated genes included those important for DNA repair, oxidative stress, and protein folding/degradation. Microarrays comprising 234 well characterized stress-related genes were used to profile transcriptomic changes in six astronauts before and after short-duration spaceflight. Blood samples were collected for analysis from each eastronaut 10 days prior and 2-3 hours after return from spaceflight. Data submitted for platform GPL140 contain genes that have been pre-filtered by the analytical software to remove values of low certainty, resulting in missing values for some samples. Unfortunately, these original data are no longer available due to physical damage at Tulane University during hurricane Katrina, but the processed values were retained in redundant locations and these are submitted for upload to GEO.

Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in setting up the spaceflight responses are being identified; their role in spaceflight physiological adaptation are increasingly understood and the fact that different genotypes adapt differently is recognized. However the basic question of whether these spaceflight responses are required for survival has yet to be posed and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses of two Arabidopsis ecotypes Col-0 and WS as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS phyD displayed a significantly reduced spaceflight transcriptome response compared to Col-0 suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS more broadly indicating that the plant genotype can be manipulated to reduce the transcriptome cost of plant physiological adaptation to spaceflight and suggesting that genetic manipulation might further reduce or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS the WS genotype actually mounted a larger transcriptome response than Col-0 suggesting that the in-space light environment affects physiological adaptation which further implies that manipulating the local habitat can also substantially impact the metabolic cost of spaceflight adaptation.

Gene expression levels were determined in 3rd instar and adult Drosophila melanogaster reared during spaceflight, to elucidate the genetic and molecular mechanisms underpinning the effects of microgravity on the immune system. The goal was to validate the Drosophila model for understanding alterations of innate immune responses in humans due to spaceflight. Five containers of flies, with ten female and five male fruit flies in each container, were housed and bred on the space shuttle (average orbit altitude of 330.35 km) for 12 days and 18.5 hours, with a new generation reared in microgravity. RNA was extracted on the day of shuttle landing from whole body animals (3rd instar larvae and adults), hybridized to Drosophila 2.0 Affymetrix genome arrays, and the expression level of all genes was normalized against the gene expression level from the corresponding developmental stage animals raised on ground. Spaceflight altered the expression of larval genes involved in the maturation of plasmatocytes (macrophages) and their phagocytic response, as well as the level of constitutive expression of pattern recognition receptors and opsonins that specifically recognize bacteria, and of lysozymes, antimicrobial peptide pathway and immune stress genes, hallmarks of humoral immunity. Larval microarrays (FL 6 samples) are based on RNA extracted from 6 independent sets of 50 mid 3rd instar larvae reared in microgravity and collected on the day of landing after 12 days and 18.5 hours on the space shuttle and the same number of control larvae raised on ground (GL 6 samples). Adults microarrays (F1 3 samples) are based on RNA from 3 sets of 20 adult females each, that emerged during spaceflight and within 4 hours of landing and the same number of adult females from the corresponding ground control containers (G1 3 samples).

The spaceflight experiment was carried out using male C57BL/10J mice (8 weeks old at launch). Wild type mice (n=3) were launched by Space Shuttle Discovery and housed on the International Space Station (ISS) for 91 days. They returned to the Earth by Space Shuttle Atlantis. But only one mouse returned to the Earth alive. Whole brain was sampled from the mouse killed by inhalation of carbon dioxide at the Life Sciences Support Facility of Kennedy Space Center within 3-4 hours after landing. After the spaceflight experiment the on-ground experiment was also carried out at the Advanced Biotechnology Center in Genova Italy. A mouse with the same species sex and age was housed in mice drawer system (MDS) which was utilized for the spaceflight (SF) mice for 3 months as the ground control (GC). Another mouse was housed in normal vivarium cage as the laboratory control (LC). Amount of food and water supplementation and environmental conditions were simulated as the flight group. After 3 months brain was sampled from one mouse in group GC and LC respectively. Comprehensive analyses of gene expression were performed in the right brain. Total of 4,000 genes were analyzed. The expression levels of 60 genes significantly changed in response to SF compared with LC and/or GC. The 15 and 16 genes were up- (> 2 folds) and down-regulated (< 0.5 folds) respectively following SF vs. GC. The levels of 58 genes were significantly altered by housing in MDS in space and/or on the ground. Forty seven and 11 genes were significantly up- and down-regulated vs. LC. Twenty seven out of these genes responded to caging in MDS both in space and on the ground. Further 31 genes were influenced by housing in MDS on the Earth. Responses of the characteristics of brain to long-term gravitational unloading were investigated in mice.

Interplanetary human spaceflight represents a formidable medical challenge but also provides a unique platform for investigating human adaptation to extreme environmental changes. Understanding the long-term effects of isolation has relevance in a range of scenarios and it is well recognized that a better understanding of the relationship between environmental exposure and the epigenome can lead to more effective preventive measures. Here we conduct a longitudinal epigenetic mood state and biochemical profiling of 6 crew members in an experiment simulating a 520-day mission to Mars. Illumina HumanMethylation450 BeadChip was used to obtain DNA methylation profiles. Firstly we found that long-term isolation can induce global DNA methylation remodeling and this change seems to be an active adaptation (rather than a random process or a by-product of the isolation). This study is the first to demonstrate the dynamic relationship between global epigenetic remodeling and isolation-induced mood state and biochemical changes. Secondly by considering the location of methylation sites within the genome and using gene-pathway annotation we were able to identify pathways that were significantly enriched in methylation events and consider their association with specific function and the timeline of the mission. Thirdly via our definition of epi-entropy a measure of entropy adapted to methylation events we observed that the methylation remodeling produced a marked reduction in epi-entropy. Results suggest that DNA methylation change is an indicator of change rather than its by-product i.e. there is a psychology-epigenome-metabolism model of long-term depression; DNA methylation programs the environment signal into the epigenome which is subsequently transformed into the biochemical output and health outcome. Thus longitudinal epigenetic profiling could code the effect of isolation and act as early indicators of latent health outcome. A longitudinal epigenetic mood state and biochemical profiling of 6 crew members in an experiment simulating a 520-day mission to Mars. 36 samples of blood cell DNA methylation profiling were obtained by Illumina HumanMethylation450 BeadChip across 6 sampling points during the 520 days mission for all of the 6 crew members.

Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response than Col-0, suggesting that the in-space light environment affects physiological adaptation, which implies that manipulating the local habitat can also substantially impact the metabolic cost of spaceflight adaptation.

In this study transcriptome profiling was used to gain insight into the spaceflight adaptation role of Altered response to gravity-1 (Arg1) a gene known to affect gravity responses in plants on Earth. The study compared expression profiles of cultured lines of Arabidopsis thaliana derived from wild type (WT) cultivar Col-0 to profiles from a knock-out line deficient in the gene encoding (ARG1 KO) both on the ground and in space. The cell lines were launched on SpaceX CRS-2 as part of the Cellular Expression Logic (CEL) experiment of the BRIC17 spaceflight mission. The cultured cell lines were grown within 60mm Petri plates in Petri Dish Fixation Units (PDFUs) that were housed within the Biological Research In Canisters (BRIC) hardware. Spaceflight samples were fixed on orbit. Differentially expressed genes were identified between the two environments (spaceflight and comparable ground controls) and the two genotypes (WT and ARG1 KO). Each genotype engaged unique genes during physiological adaptation to the spaceflight environment with little overlap. Most of the genes altered in expression in spaceflight in WT cells were found to be Arg1-dependent suggesting a major role for that gene in the physiological adaptation of undifferentiated cells to spaceflight.

Spaceflight results in a number of adaptations to skeletal muscle including atrophy and shifts towards faster muscle fiber types. To identify changes in gene expression that may underlie these adaptations microarray expression analysis was performed on gastrocnemius from mice flown on the STS-108 shuttle flight (11 days 19 hours) versus mice maintained on earth for the same period. Additionally to identify changes that were due to unloading and reloading microarray analyses were conducted on calf muscle from ground-based mice subjected to hindlimb suspension (12 days) and mice subjected to hindlimb suspension plus a brief period of reloading (3.5 hours) to simulate the time between landing and sacrifice of the spaceflight mice.

The demands of deep space pose a health risk to the central nervous system that has long been a concern when sending humans to space. While little is known about how spaceflight affects transcription spatially in the brain, a greater understanding of this process has the potential to aid strategies that mitigate the effects of spaceflight on the brain. Therefore, we performed GeoMx Digital Spatial Profiling of mouse brains subjected to either spaceflight or grounded controls. Four brain regions were selected: Cortex, Frontal Cortex, Corunu Ammonis I, and Dentate Gyrus. Antioxidants have emerged as a potential means of attenuating the effects of spaceflight, so we treated a subset of the mice with a superoxide dismutase mimic, MnTnBuOE-2-PyP 5+ (BuOE). Our analysis revealed hundreds of differentially expressed genes due to spaceflight in each of the four brain regions. Both common and region-specific transcriptomic responses were observed. Metabolic pathways and pathways sensitive to oxidative stress were enriched in the four brain regions due to spaceflight. These findings enhance our understanding of brain regional variation in susceptibility to spaceflight conditions. BuOE reduced the transcriptomic effects of spaceflight at a large number of genes, suggesting that this compound may attenuate oxidative stress-induced brain damage caused by the spaceflight environment. This study contains data of frontal cortex region. The data of other brain regions are deposited in OSD-682 (cornu ammonis 1), OSD-685 (dentate gyrus), and OSD-699 (cerebral cortex).