Controlled hypobaria presents biology with an environment that is never encountered in terrestrial ecology yet the apparent components of hypobaria are stresses typical of terrestrial ecosystems. High altitude for example presents terrestrial hypobaria always with hypoxia as a component stress since the relative partial pressure of O2 is constant in the atmosphere. Laboratory-controlled hypobaria however allows the dissection of pressure effects away from the effects typically associated with altitude in particular hypoxia as the partial pressure of O2 can be varied. In this study whole transcriptomes of plants grown in ambient (97 kPa/pO2 = 21 kPa) atmospheric conditions were compared to those of plants transferred to five different atmospheres of varying pressure and oxygen composition for 24 h: 50 kPa/pO2 = 10 kPa 25 kPa/pO2 = 5 kPa 50 kPa/pO2 = 21 kPa 25 kPa/pO2 = 21 kPa or 97 kPa/pO2 = 5 kPa. The plants exposed to these environments were 10 day old Arabidopsis seedlings grown vertically on hydrated nutrient plates. In addition 5 day old plants were also exposed for 24 h to the 50 kPa and ambient environments to evaluate age-dependent responses. The gene expression profiles from roots and shoots showed that the hypobaric response contained more complex gene regulation than simple hypoxia and that adding back oxygen to normoxic conditions did not completely alleviate gene expression changes in hypobaric responses.

Age plays a crucial role in the interplay between tumor and host; with further perturbations induced by irradiation. Proton irradiation on tumors induces biological modulations including inhibition of angiogenic and immune factors critical to hallmark processes impacting tumor development in addition to physical targeting advantages. These advantages have provided promising results for proton therapy in cancer. Additionally protons have implications for carcinogenesis risk of space travel (due to the high proportion of high energy protons in space radiation). Through a systems biology approach we investigated how host tissue (i.e. splenic tissue) of tumor-bearing mice is altered with age with or without whole-body proton exposure. Transcriptome analysis was performed on splenic tissue from adolescent (68 day) versus old (736 day) C57BL/6 male mice injected with Lewis lung carcinoma cells with or without three fractionations of 0.5Gy (1GeV) proton irradiation. Global transcriptome analysis indicated that proton irradiation of adolescent hosts caused significant signaling changes within splenic tissues that support carcinogenesis within the mice as compared to old subjects. Increases in cell cycling and immunosuppression in irradiated adolescent hosts with CDK2 MCM7 CD74 and RUVBL2 as the key players were involved in the regulatory changes in host environment response (i.e. spleen). These results suggest a significant biological component to proton irradiation operative through host age that would indicate a modulation of host s ability to support carcinogenesis in adolescence and the bestowal of resistance to immunosuppression carcinogenesis and genetic perturbation by old age.

Entire microRNA expression were analyzed using the Filgen Array miRNA Caenorhabditis elegans 232 probes (Filgen). In the microRNA expression analysis we compared the expression data between two groups: micro-gravity samples (4 d and 8 d) and controls (4 d and 8 d ground control and 1 G centrifuge onboard ISS).

The present study concerns the effects of 21 days of sustained recumbence (bedrest) on skeletal muscle gene expression. 14 male subjects participated in normoxic bedrest (NBR) with muscle unloading for 21 days this is a substudy of tha PlanHab-study which apart from normoxic bedrest also involved hypoxic bedrest and hypoxic ambulation. Throughout both bedrest interventions each subject remained in a horizontal position at all times. He was allowed one pillow for the head and to occasionally lean on an elbow while eating or being transferred to a gurney. Muscular exercise was prohibited. During the HAMB confinement each subject was allowed to move freely within the hypoxic area. To mimic a normal level of physical activity subjects performed 30 minutes of low-to-moderate-intensity exercise twice daily. Muscle samples from Vastus lateralis.

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.

We investigated differentially regulated genes in human Jurkat T lymphocytic cells in 20s and 5min microgravity and in hypergravity and compared expression profiles to identify potential gravity-regulated genes and adaptation processes. This dataset is part of a series of three and the other two datasets are deposited in GLDS-172 and GLDS-189.

We investigated differentially regulated and stably expressed genes in human Jurkat T lymphocytic cells in 5min simulated microgravity and hypergravity and compared expression profiles to identify gravity-regulated and unaffected genes as well as adaptation processes. This dataset is part of a series of three and the other two datasets are deposited in GLDS-172 and GLDS-188.

Microgravity or an altered gravity environment from the static 1g has been shown to influence global gene expression patterns and protein levels in cultured cells or animals but it is unclear how these changes in gene and protein expressions are related to each other or are related to other factors regulating such changes. Recent advancement in the field of molecular biology revealed that a different class of RNA the small non-coding microRNA (miRNA) can have a broad effect on gene expression networks by mainly inhibiting the translational process. In this experiment conducted on the International Space Station we propose to test the hypotheses that miRNA profiles will be altered in the space environment and that cellular responses to DNA damage in space are different from those on the ground.

Controlled hypobaria presents biology with an environment that is never encountered in terrestrial ecology yet the apparent components of hypobaria are stresses typical of terrestrial ecosystems. High altitude for example presents terrestrial hypobaria always with hypoxia as a component stress since the relative partial pressure of O2 is constant in the atmosphere. Laboratory-controlled hypobaria however allows the dissection of pressure effects away from the effects typically associated with altitude in particular hypoxia as the partial pressure of O2 can be varied. In this study whole transcriptomes of plants grown in ambient (97 kPa/pO2 = 21 kPa) atmospheric conditions were compared to those of plants transferred to five different atmospheres of varying pressure and oxygen composition for 24 h: 50 kPa/pO2 = 10 kPa 25 kPa/pO2 = 5 kPa 50 kPa/pO2 = 21 kPa 25 kPa/pO2 = 21 kPa or 97 kPa/pO2 = 5 kPa. The plants exposed to these environments were 10 day old Arabidopsis seedlings grown vertically on hydrated nutrient plates. In addition 5 day old plants were also exposed for 24 h to the 50 kPa and ambient environments to evaluate age-dependent responses. The gene expression profiles from roots and shoots showed that the hypobaric response contained more complex gene regulation than simple hypoxia and that adding back oxygen to normoxic conditions did not completely alleviate gene expression changes in hypobaric responses.

Exposure to radiation provokes cellular responses controlled in part by gene expression networks. MicroRNAs (miRNAs) are small non-coding RNAs which mostly regulate gene expression by degrading the messages or inhibiting translation. Here we investigated changes in miRNA expression patterns after low (0.1 Gy) and high (2.0 Gy) doses of X-ray in human fibroblasts. At early (0.5 h) and late (6 and 24 h) time points irradiation caused qualitative and quantitative differences in the down-regulation of miRNA levels including miR-92b 137 660 and 656. A transient up-regulation of miRNAs was observed after 2 h post-irradiation following high doses of radiation including miR-558 and 662. MicroRNA levels were inversely correlated with targets from mRNA and proteomic profiling after 2.0 Gy of radiation. MicroRNAs miR-579 608 548-3p and 585 are noted for targeting genes involved in radioresponsive mechanisms such as cell cycle checkpoint and apoptosis. We suggest here a model in which miRNAs may act as hub regulators of specific cellular responses immediately down-regulated so as to stimulate DNA repair mechanisms followed by up-regulation involved in suppressing apoptosis for cell survival. Taken together miRNAs may mediate signaling pathways in sequential fashion in response to radiation and may serve as biodosimetric markers of radiation exposure. Overall design: The gene expression patterns in human fibroblasts after 2.0 Gy of low-LET radiation was determined at 2 and 24 hrs post-irradiation time in technical triplicates. Control non-irradiated samples were also prepared in triplicates.