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: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:Microgravity effect on C. elegans gene expression was analysed by whole genome microarray. The worms were cultivated under microgravity for 8days in the Japanese Module of the International Space Station.
Project description:Microgravity effect on C. elegans gene expression was analysed by whole genome microarray. The worms were cultivated under microgravity for 4 days in the Japanese Module of the International Space Station.
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.