Project description:The goal of this study was to assess whether low shear-modeled microgravity (LSMMG) effects yeast ,genomic expression patterns using the powerful tool of whole genome microarray hybridization. We determined ,changes in the yeast model organism, Saccharomyces cerevisisae, when grown in LSMMG using the rotating High ,Aspect Ratio Vessel (HARV). A significant number of genes were up- or down-regulated by at least two fold in cells ,that were grown for 5 generations or 25 generations in HARVs. We identified genes in cell wall integrity signaling ,pathways containing MAP kinase cascades that may provide clues to novel physiological responses of eukaryotic ,cells to the external stress of a low-shear modeled microgravity environment. A comparison of the microgravity ,response to other environmental stress response (ESR) genes showed that 26% of the genes that respond ,significantly to LSMMG are involved in a general environmental stress response, while 74% of the genes may ,represent a unique transcriptional response to microgravity. In addition, we found changes in genes involved in ,budding, cell polarity establishment, and cell separation that confirm our hypothesis that exposure to LSMMG ,causes changes in gene transcription resulting in a phenotypic response. The results of the study provide interesting ,clues to potential mechanisms involved in the response to, adaptation to, and survival of eukaryotic cells in a ,microgravity environment and our findings may have important health implications for human spaceflight. Experiment Overall Design: Four conditions are compared with three replicates each: yeast grown in low-shear modeled microgravity (HARV bioreactor) for 5 and 25 generations; yeast grown in a horizontal (non-LSMMG) HARV bioreactor for 5 and 25 generations.
Project description:BACKGROUND: Ionizing radiation (IR) can be extremely harmful for human cells since an improper DNA-damage response (DDR) to IR can contribute to carcinogenesis initiation. Perturbations in DDR pathway can originate from alteration in the functionality of the microRNA-mediated gene regulation, being microRNAs (miRNAs) small noncoding RNA that act as post-transcriptional regulators of gene expression. In this study we gained insight into the role of miRNAs in the regulation of DDR to IR under microgravity, a condition of weightlessness experienced by astronauts during space missions, which could have a synergistic action on cells, increasing the risk of radiation exposure. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed miRNA expression profile of human peripheral blood lymphocytes (PBL) incubated for 4 and 24 h in normal gravity (1 g) and in modeled microgravity (MMG) during the repair time after irradiation with 0.2 and 2Gy of γ-rays. Our results show that MMG alters miRNA expression signature of irradiated PBL by decreasing the number of radio-responsive miRNAs. Moreover, let-7i*, miR-7, miR-7-1*, miR-27a, miR-144, miR-200a, miR-598, miR-650 are deregulated by the combined action of radiation and MMG. Integrated analyses of miRNA and mRNA expression profiles, carried out on PBL of the same donors, identified significant miRNA-mRNA anti-correlations of DDR pathway. Gene Ontology analysis reports that the biological category of "Response to DNA damage" is enriched when PBL are incubated in 1 g but not in MMG. Moreover, some anti-correlated genes of p53-pathway show a different expression level between 1 g and MMG. Functional validation assays using luciferase reporter constructs confirmed miRNA-mRNA interactions derived from target prediction analyses. CONCLUSIONS/SIGNIFICANCE: On the whole, by integrating the transcriptome and microRNome, we provide evidence that modeled microgravity can affects the DNA-damage response to IR in human PBL.
Project description:BACKGROUND: Ionizing radiation (IR) can be extremely harmful for human cells since an improper DNA-damage response (DDR) to IR can contribute to carcinogenesis initiation. Perturbations in DDR pathway can originate from alteration in the functionality of the microRNA-mediated gene regulation, being microRNAs (miRNAs) small noncoding RNA that act as post-transcriptional regulators of gene expression. In this study we gained insight into the role of miRNAs in the regulation of DDR to IR under microgravity, a condition of weightlessness experienced by astronauts during space missions, which could have a synergistic action on cells, increasing the risk of radiation exposure. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed miRNA expression profile of human peripheral blood lymphocytes (PBL) incubated for 4 and 24 h in normal gravity (1 g) and in modeled microgravity (MMG) during the repair time after irradiation with 0.2 and 2Gy of γ-rays. Our results show that MMG alters miRNA expression signature of irradiated PBL by decreasing the number of radio-responsive miRNAs. Moreover, let-7i*, miR-7, miR-7-1*, miR-27a, miR-144, miR-200a, miR-598, miR-650 are deregulated by the combined action of radiation and MMG. Integrated analyses of miRNA and mRNA expression profiles, carried out on PBL of the same donors, identified significant miRNA-mRNA anti-correlations of DDR pathway. Gene Ontology analysis reports that the biological category of "Response to DNA damage" is enriched when PBL are incubated in 1 g but not in MMG. Moreover, some anti-correlated genes of p53-pathway show a different expression level between 1 g and MMG. Functional validation assays using luciferase reporter constructs confirmed miRNA-mRNA interactions derived from target prediction analyses. CONCLUSIONS/SIGNIFICANCE: On the whole, by integrating the transcriptome and microRNome, we provide evidence that modeled microgravity can affects the DNA-damage response to IR in human PBL.
Project description:The goal of this study was to assess whether low shear-modeled microgravity (LSMMG) effects yeast genomic expression patterns using the powerful tool of whole genome microarray hybridization. We determined changes in the yeast model organism, Saccharomyces cerevisisae, when grown in LSMMG using the rotating High Aspect Ratio Vessel (HARV). A significant number of genes were up- or down-regulated by at least two fold in cells that were grown for 5 generations or 25 generations in HARVs. We identified genes in cell wall integrity signaling pathways containing MAP kinase cascades that may provide clues to novel physiological responses of eukaryotic cells to the external stress of a low-shear modeled microgravity environment. A comparison of the microgravity response to other environmental stress response (ESR) genes showed that 26% of the genes that respond significantly to LSMMG are involved in a general environmental stress response, while 74% of the genes may represent a unique transcriptional response to microgravity. In addition, we found changes in genes involved in budding, cell polarity establishment, and cell separation that confirm our hypothesis that exposure to LSMMG causes changes in gene transcription resulting in a phenotypic response. The results of the study provide interesting clues to potential mechanisms involved in the response to, adaptation to, and survival of eukaryotic cells in a microgravity environment and our findings may have important health implications for human spaceflight. Keywords: time course, stress response, budding, microgravity
Project description:In space, multiple unique environmental factors, particularly microgravity and space radiation, pose constant threat to the astronaut’s health. To gain insight into the role of miRNAs and lncRNAs in response to radiation and microgravity, we analyzed RNA expression profiles in human lymphoblastoid TK6 cells incubated for 24 h in static condition or in rotating condition to stimulate microgravity in space after 2 Gy γ-ray irradiation. Expression of 14 lncRNAs and 17 mRNAs was found to be significantly down-regulated in the simulated microgravity condition. In contrast, irradiation up-regulated the expression of 55 lncRNAs and 56 mRNAs, while only one lncRNA, but no mRNA, was down-regulated. Furthermore, 2 miRNAs, 70 lncRNAs, and 87 mRNAs showed significantly altered expression under simulated microgravity after irradiation, and these changes were independently induced by irradiation and simulated microgravity. Together, our results indicate that simulated microgravity and irradiation additively and independently alter the expression of RNAs and their target genes in human lymphoblastoid cells.
Project description:Most studies have analysed the effects of high dose radiation such as atomic bomb survivors in Japan, people exposed during the Chernobyl nuclear accident, patients undergoing radiation therapy, uranium miners, etc. However, it has been difficult to measure and assess the risk of cancer in people exposed to lower doses of ionising radiation, such as the people living at high altitudes, who are exposed to more natural background radiation from cosmic rays than people at sea level. We measured the genomic response to X-ray ionising radiation (10 cGy and 100 cGy) in a skin tissue model to compare the effects of low and high dose ionising radiation at different time points. The microarray data was then analysed using state-of-the art “upside-down pyramid” computational systems biology methods to identify genes contributing to the difference in the response to the different radiation doses.
Project description:Abstract Purpose: There is a recognised need to develop new methods of high throughput, rapid and minimally invasive individual dose assessment for radiation exposure. The aim of this work is to establish a panel of highly radiation responsive genes suitable for biological dosimetry and to explore inter-individual variation in response to ionising radiation exposure.Materials and method: Analysis of gene expression in response to radiation was carried out using three independent techniques (microarray, Multiplex Quantitative RT-PCR and nCounter Analysis System) in human lymphocytes in culture and circulating blood exposed ex vivo from the same donors. Results: Variations in transcriptional response to exposure to ionising radiation analysed by microarray allowed the identification of genes which can be validated and measured accurately as biomarkers of radiation exposure using other techniques. We have identified genes which are consistently up-regulated following exposure at different time points to either 2 or 4 Gy of X-rays, for all individuals in blood and cultured lymphocytes. Most down-regulated genes including cyclins, centromeric and mitotic checkpoints proteins, particularly those associated with chromosome instability and cancer can only be detected in dividing cells. Conclusions: The data provides evidence that there are a number of genes which seem suitable for biological dosimetry, like SESN1, GADD45A, CDKN1A, CCNG1, FDXR, BBC3 and MDM2. ÊThese biomarkers could potentially be used for triage after large-scale radiological incidents. Variations in transcriptional response accurately measured by MQRT-PCRæ may allow the identification of biomarkers of radiation sensitivity and individual susceptibility and therefore being useful in radiation oncology.
Project description:R. rubrum S1H inoculated on solid minimal media was sent to the ISS in September 2006 (BASE-A experiment). After 10 days flight, R. rubrum cultures returned back to Earth. These cultures were then subjected to both transcriptomic and proteomic analysis and compared with the corresponding ground control. Whole-genome oligonucleotide microarray and high throughput proteomics, which offer the possibility to survey respectively the global transcriptional and translational response of an organism, were used to test the effect of space flight. Moreover, in an effort to identify a specific stress response of R. rubrum to space flight, ground simulation of space ionizing radiation and space gravity were performed under identical culture setup and growth conditions encountered during the actual space journey. This study is unique in combining the results from an actual space experiment with the corresponding space ionizing radiation and modeled microgravity ground simulations, which lead to a more solid dissection of the different factors contribution acting in space flight conditions. Total RNA was extracted from R. rubrum S1H grown after 10 days in space flight or after 10 days in simulated ionizing radiation or simulated microgravity. Each microarray slide contained 3 technical repeats.
Project description:R. rubrum S1H inoculated on solid agar rich media was sent to the ISS in October 2003 (MESSAGE-part 2 experiment). After 10 days flight, R. rubrum cultures returned back to Earth. These cultures were then subjected to both transcriptomic and proteomic analysis and compared with the corresponding ground control. Whole-genome oligonucleotide microarray and high throughput proteomics, which offer the possibility to survey respectively the global transcriptional and translational response of an organism, were used to test the effect of space flight. Moreover, in an effort to identify a specific stress response of R. rubrum to space flight, ground simulation of space ionizing radiation and space gravity were performed under identical culture setup and growth conditions encountered during the actual space journey. This study is unique in combining the results from an actual space experiment with the corresponding space ionizing radiation and modeled microgravity ground simulations, which lead to a more solid dissection of the different factors contribution acting in space flight conditions. Total RNA was extracted from R. rubrum S1H grown after 10 days in space flight or after 10 days in simulated ionizing radiation or simulated microgravity. Each microarray slide contained 3 technical repeats.