While it has been shown that astronauts suffer immune disorders after spaceflight the underlying causes are still poorly understood and there are many variables to consider when investigating the immune system in a complex environment. Additionally there is growing evidence that suggests that not only is the immune system being altered but the pathogens that infect the host are significantly influenced by spaceflight and ground-based spaceflight conditions. In this study we demonstrate that Serratia marcescens (strain Db11) was significantly more lethal to Drosophila melanogaster after growth on the International Space Station than ground-based controls but that the host immune system is not significantly altered amongst known immune genes. High-throughput sequencing of wild-type (w1118) adult hosts infected with either space or ground-reared S. marcescens revealed few changes in gene expression with 11 genes significantly differentially expressed (q-values <0.05) and only one gene related to the immune system. This data supports the main findings of the paper which state that both spaceflight and low-shear modeled microgravity conditions increase the virulence of this pathogen independent of the host immune system. This data which shows that there are no significant immune-related changes to the host when infected with space-grown sample compared to ground-grown sample provides further evidence that there are likely phenotypic changes to the pathogen itself that is causing increased virulence in spaceflight and in low-shear modeled microgravity. RNA was extracted in triplicate from 2 pooled adult (2-3 day old female) Drosophila melanogaster (w1118) per treatment with 4 total treatment groups (no injection control sham injection with PBS ground bacteria-injected and space bacteria-injected) with poly(A)+ RNA libraries. Samples were multiplexed and sequenced 100bp paired-end ready were sequenced on one lane of the Illumina HiSeq-4000.

Physical forces associated with spaceflight and spaceflight analogue culture regulate a wide range of physiological responses by both bacterial and mammalian cells that can impact infection. However, our mechanistic understanding of how these environments regulate host-pathogen interactions in humans is poorly understood. Using a spaceflight analogue low fluid shear culture system, we investigated the effect of Low Shear Modeled Microgravity (LSMMG) culture on the colonization of Salmonella Typhimurium in a 3-D biomimetic model of human colonic epithelium containing macrophages. RNA-seq profiling of stationary phase wild type and delta hfq mutant bacteria alone indicated that LSMMG culture induced global changes in gene expression in both strains and that the RNA-binding protein Hfq played a significant role in regulating the transcriptional response of the pathogen to LSMMG culture. However, a core set of genes important for adhesion, invasion, and motility were commonly induced in both strains. LSMMG culture enhanced the colonization (adherence, invasion and intracellular survival) of Salmonella in this advanced model of intestinal epithelium using a mechanism that was independent of Hfq. Although S. Typhimurium delta hfq mutants are normally defective for invasion when grown as conventional shaking cultures, LSMMG conditions unexpectedly enabled high levels of colonization by an isogenic hfq mutant. In response to infection with either the wild type or mutant, host cells upregulated transcripts involved in inflammation, tissue remodeling, and wound healing during intracellular survival. Interestingly, infection by the hfq mutant led to fewer transcriptional differences between LSMMG- and control-infected host cells relative to infection with the wild type strain. This is the first study to investigate the effect of LSMMG culture on the interaction between S. Typhimurium and a 3-D model of human intestinal tissue. These findings advance our understanding of how physical forces can impact the early stages of human enteric salmonellosis.

Space travel presents unlimited opportunities for exploration and discovery, but requires a more complete understanding of the immunological consequences of long-term exposure to the conditions of spaceflight. To understand these consequences better and to contribute to design of effective countermeasures, we used the Drosophila model to compare innate immune responses to bacteria and fungi in flies that were either raised on earth or in outer space aboard the NASA Space Shuttle Discovery (STS-121). Microarrays were used to characterize changes in gene expression that occur in response to infection by bacteria and fungus in drosophila that were either hatched and raised in outer space (microgravity) or on earth (normal gravity). Whole Oregon R strain drosophila melanogaster fruit flies either raised on earth or in space that were (1) uninfected, (2) infected with bacteria (Escherichia coli), or (3) infected with fungus (Beauveria bassiana) were used for RNA extraction and hybridization on Affymetrix microarrays.

The introduction of generally recognized as safe (GRAS) probiotic microbes into the spaceflight food system has the potential for use as a safe, non-invasive, daily countermeasure to crew microbiome and immune dysregulation. However, the microgravity effects on the stress tolerances and genetic expression of probiotic bacteria must be determined to confirm translation of strain benefits and to identify potential for optimization of growth, survival, and strain selection for spaceflight. The work presented here demonstrates the translation of characteristics of a GRAS probiotic bacteria to a microgravity analog environment. Lactobacillus acidophilus ATCC 4356 was grown in the low shear modeled microgravity (LSMMG) orientation and the control orientation in the rotating wall vessel (RWV) to determine the effect of LSMMG on the growth, survival through stress challenge, and gene expression of the strain. No differences were observed between the LSMMG and control grown L. acidophilus, suggesting that the strain will behave similarly in spaceflight and may be expected to confer Earth-based benefits.

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.

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).

Space exploration exposes astronauts to stressors that alter the immune response, rendering them vulnerable to infections and diseases. In this study, we aimed to determine the levels of inflammasome activation in the brains of mice that were housed in the International Space Station (ISS) for 37 days. C57BL/6 mice were launched to the ISS as part of NASA’s Rodent Research 1 Mission on SpaceX-4 CRS-4 Dragon cargo spacecraft from September 21st, 2014, to October 25th, 2014. Dissected mouse brains from that mission were analyzed by immunoblotting of inflammasome signaling proteins and Electrochemiluminescence Immunoassay (ECLIA) for inflammatory cytokine levels. Our data indicate decreased inflammasome activation in the brains of mice that were housed in the ISS for 37 days when compared to the brains of mice that were maintained on the ground, and in mice corresponding to the baseline group that were sacrificed at the time of launching of SpaceX-4. Moreover, we did not detect any significant changes in the expression levels of the pro-inflammatory cytokines TNF-alpha, IL-2, IFN-gamma, IL-5, IL-6, IL-12p70 and IL-10 between the ground control and the flight groups. Together, these studies suggest that spaceflight results in a decrease in the levels of innate immune signaling molecules that govern inflammasome signaling in the brain of mice. This dataset derives results from the ECLIA and Western Blot assays using brain tissue.

Space exploration exposes astronauts to stressors that alter the immune response, rendering them vulnerable to infections and diseases. In this study, we aimed to determine the levels of inflammasome activation in the brains of mice that were housed in the International Space Station (ISS) for 37 days. C57BL/6 mice were launched to the ISS as part of NASA’s Rodent Research 1 Mission on SpaceX-4 CRS-4 Dragon cargo spacecraft from September 21st, 2014, to October 25th, 2014. Dissected mouse brains from that mission were analyzed by immunoblotting of inflammasome signaling proteins and Electrochemiluminescence Immunoassay (ECLIA) for inflammatory cytokine levels. Our data indicate decreased inflammasome activation in the brains of mice that were housed in the ISS for 37 days when compared to the brains of mice that were maintained on the ground, and in mice corresponding to the baseline group that were sacrificed at the time of launching of SpaceX-4. Moreover, we did not detect any significant changes in the expression levels of the pro-inflammatory cytokines TNF-alpha, IL-2, IFN-gamma, IL-5, IL-6, IL-12p70 and IL-10 between the ground control and the flight groups. Together, these studies suggest that spaceflight results in a decrease in the levels of innate immune signaling molecules that govern inflammasome signaling in the brain of mice. This dataset derives results from the ECLIA assay using brain tissue.

This study presents the first global transcriptional profiling and phenotypic characterization of the major human opportunistic fungal pathogen, Candida albicans, grown in spaceflight conditions. Microarray analysis revealed that C. albicans subjected to short-term spaceflight culture differentially regulated 454 genes compared to synchronous ground controls, which represented 8.4% of the analyzed ORFs. Spaceflight-cultured C. albicans induced genes involved in cell aggregation (similar to flocculation), which was validated by microscopic and flow cytometry analysis. We also observed enhanced random budding of spaceflight-cultured cells as opposed to more normal bipolar budding patterns for ground samples, in accordance with the gene expression data. Furthermore, genes involved in antifungal agent and stress resistance were differentially regulated in spaceflight, including induction of ABC transporters and members of the major facilitator family, downregulation of ergosterol-encoding genes, and upregulation of genes involved in oxidative stress resistance. Finally, downregulation of genes involved in the actin cytoskeleton was observed. Interestingly, the transcriptional regulator Cap1 and over 30% of the Cap1 regulon was differentially expressed in spaceflight-cultured C. albicans. A potential role for Cap1 in the spaceflight response of C. albicans is suggested, as this regulator is involved in random budding, cell aggregation, actin cytoskeleton, and oxidative stress resistance; all related to observed spaceflight-associated changes of C. albicans. While culture of C. albicans in microgravity potentiates a global change in gene expression that could induce a virulence-related phenotype, no increased virulence in a murine intraperitoneal (i.p.) infection model was observed. This study represents an important basis for the assessment of the risk that commensal flora could play during spaceflight missions. Furthermore, since the low fluid-shear environment of microgravity is relevant to physical forces encountered by pathogens during the infection process, insights gained from this study could identify novel infectious disease mechanisms, with downstream benefits for the general public. Cells were grown for 24 hours on the space shuttle or as ground-based controls, preserved in RNALater, and stored at -80C. Four samples of each flight- and ground-based controls were harvested for microarray analysis. GAP is Group Activation Pack and each GAP contains 8 FPAs. The numbers represent the # assigned to the particular GAP and the number assigned to the specific FPA (1-8) within the indicated GAP. The same hardware is used for the flight samples and the ground samples.

Spaceflight poses risks to the central nervous system (CNS), and understanding neurological responses is important for future missions. We report CNS changes in Drosophila aboard the International Space Station in response to spaceflight microgravity (SFμg) and artificially simulated Earth gravity (SF1g) via inflight centrifugation as a countermeasure. While inflight behavioral analyses of SFμg exhibit increased activity, postflight analysis displays significant climbing defects, highlighting the sensitivity of behavior to altered gravity. Multi-omics analysis shows alterations in metabolic, oxidative stress and synaptic transmission pathways in both SFμg and SF1g; however, neurological changes immediately postflight, including neuronal loss, glial cell count alterations, oxidative damage, and apoptosis, are seen only in SFμg. Additionally, progressive neuronal loss and a glial phenotype in SF1g and SFμg brains, with pronounced phenotypes in SFμg, are seen upon acclimation to Earth conditions. Overall, our results indicate that artificial gravity partially protects the CNS from the adverse effects of spaceflight. This study derives results from the in-flight video analysis (video recording assay).