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).

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.

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.

We address a key baseline question of whether gene expression changes are induced by the orbital environment and then we ask whether undifferentiated cells cells presumably lacking the typical gravity response mechanisms perceive spaceflight. Arabidopsis seedlings and undifferentiated cultured Arabidopsis cells were launched in April 2010 as part of the BRIC-16 flight experiment on STS-131. Biologically replicated DNA microarray and averaged RNA digital transcript profiling revealed several hundred genes in seedlings and cell cultures that were significantly affected by launch and spaceflight. The response was moderate in seedlings; only a few genes were induced by more than 7-fold and the overall intrinsic expression level for most differentially expressed genes was low. In contrast cell cultures displayed a more dramatic response with dozens of genes showing this level of differential expression a list comprised primarily of heat shock-related and stress-related genes. This baseline transcriptome profiling of seedlings and cultured cells confirms the fundamental hypothesis that survival of the spaceflight environment requires adaptive changes that are both governed and displayed by alterations in gene expression. The comparison of intact plants with cultures of undifferentiated cells confirms a second hypothesis: undifferentiated cells can detect spaceflight in the absence of specialized tissue or organized developmental structures known to detect gravity.

We developed a mouse model that captures radiation effects on host biology by transplanting unirradiated Trp53 null mammary tissue to sham or irradiated hosts. Gene expression profiles of tumors that arose in irradiated mice are distinct from those that arose in naive hosts. Host irradiation induces a metaprofile consisting of gene modules representing stem cells cell motility macrophages and autophagy. Human orthologs of the host irradiation metaprofile discriminated between radiation-preceded and sporadic human thyroid cancers. An irradiated host centroid was strongly associated with estrogen receptor negative breast cancer. When applied to sporadic human breast cancers the irradiated host metaprofile strongly associated with basal-like and claudin-low breast cancer intrinsic subtypes. Comparing host irradiation in the context of TGFB levels showed that inflammation was robustly associated with claudin-low tumors. The association of the irradiated host metaprofiles with estrogen receptor negative status and claudin-low subtype suggests that host processes similar to those induced by radiation underlie sporadic cancers. Total RNA was extracted from mammary tumors derived from transplantations of non-irradiated p53null mammary fragments into irradiated hosts. We analyized a total of 32 p53null tumors from irradiated wild type mice: 9 from sham-irradiated hosts and 23 from irradiated hosts. We also analyzed 24 tumors from irradiated TGFb1 heterozygote hosts: 6 from sham-irradiated hosts and 18 from irradiated hosts.

We developed a mouse model that captures radiation effects on host biology by transplanting unirradiated Trp53 null mammary tissue to sham or irradiated hosts. Gene expression profiles of tumors that arose in irradiated mice are distinct from those that arose in naive hosts. Host irradiation induces a metaprofile consisting of gene modules representing stem cells cell motility macrophages and autophagy. Human orthologs of the host irradiation metaprofile discriminated between radiation-preceded and sporadic human thyroid cancers. An irradiated host centroid was strongly associated with estrogen receptor negative breast cancer. When applied to sporadic human breast cancers the irradiated host metaprofile strongly associated with basal-like and claudin-low breast cancer intrinsic subtypes. Comparing host irradiation in the context of TGFB levels showed that inflammation was robustly associated with claudin-low tumors. The association of the irradiated host metaprofiles with estrogen receptor negative status and claudin-low subtype suggests that host processes similar to those induced by radiation underlie sporadic cancers. Total RNA was extracted from mammary tumors derived from transplantations of non-irradiated p53null mammary fragments into irradiated hosts. We analyized a total of 32 p53null tumors from irradiated wild type mice: 9 from sham-irradiated hosts and 23 from irradiated hosts. We also analyzed 24 tumors from irradiated TGFb1 heterozygote hosts: 6 from sham-irradiated hosts and 18 from irradiated hosts.

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.

Analysis of human peripheral blood 48 hours after irradiation ex vivo with graded doses of gamma rays. Results have been used in building and testing classifiers to predict exposure dose for use in radiological triage and also provide insight into immune cell responses. Results were compared with those from earlier times and from patients exposed in vivo. Peripheral blood from 5 healthy donors was exposed ex vivo to 0. 0.5 2 5 or 8 Gy gamma-rays and gene expression was analyzed up to 48 hours after exposure.