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.

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).

Here we present a whole-genome survey of the murine transcriptomic response to physiologically-relevant radiation doses 2 and 8 Gy. There are 18 distinct biological samples here. Mice were exposed to ionizing radiation (Cesium-138 source) and whole blood was collected by cardiac puncture 6 hours post treatment. Doses were 0 (7 samples) 2 (5 samples) and 8 (6 samples) gy.

We used microarrays to investigate the effects of microgravity and space radiation on the genome-wide expression of the C. elegans. Three technical replicates of wild type C. elegans (CC1 strain) which exposed to space radiation are analyzed along with ground control.

One of the most likely risks astronauts on long duration space missions face is exposure to ionizing radiation associated with highly energetic and charged heavy (HZE) particles. Since access to medical expertise on such a mission is limited at best early diagnosis and mitigation of such exposure is critical. In order to accurately determine the dosage within 1 hour post-exposure dose-dependent biomarkers are needed. Therefore we performed a dose-course transcriptional analysis for radiation exposure at 0 0.3 1.5 and 3.0 Gy with corresponding time point at 1 hour (hr) post-exposure using Affymetrix GeneChip Human Gene 1.0 ST v1 Array chips. The analysis of our data suggests a set of sensitive genetic biomarkers specific to each radiation level as well as generic radiation response biomarkers. Upregulated biomarkers can then be used within lab-on-a-chip (LOC) systems to detect exposure to ionizing radiation. A total of sixteen human samples representing radiation exposure at levels 0 Gy 0.3 Gy 1.5 Gy and 3.0 Gy at time point 1 hour (hr) post-exposure were constructed. Blood samples were extracted from four human volunteers and were irradiated. Leukocytes were extracted and gene expression was measured. Samples for all four volunteers were measured at 1 hr for all four dose levels resulting in four replicates at each dose level. Thus a total of 4 samples at each of the four radiation levels were sampled yielding the total of 16 samples.

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.

We used microarrays to investigate the effects of microgravity and space radiation on the genome-wide expression of the C. elegans. Three technical replicates of wild type C. elegans (CC1 strain) which exposed to space radiation are analyzed along with ground control.

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.

The effect of microgravity on gene expression in C.elegans was comprehensively analysed by DNA microarray. This is the first DNA microarray analysis for C.elegans grown under microgravity. Hyper gravity and clinorotation experiments were performed as reference against the flight experiment.

Changes in gene expression profiles implicated in oxidative stress and in ECM remodeling in mouse skin were examined after space flight. The metabolic effects of space flight in skin tissues were also characterized.