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: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 and space radiation (SR) are two highly influential factors affecting humans in space flight. Many health problems reported by astronauts derive from endothelial dysfunction and impaired homeostasis. Here we describe the adaptive response of human, capillary endothelial cells to space. Reference samples on ground and at 1g onboard allowed discrimination between the contribution of microgravity and SR within the combined response to space. Cell softening and reduced motility occurred in space, with loss of actin stress fibers and a greater distribution of microtubules and intermediate filaments in compensation. The frequency of primary cilia also increased. DNA repair mechanisms were indeed activated. Transcriptomics highlighted the opposing effect of microgravity from SR on specific molecular pathways: radiation, unlike microgravity, stimulated pathways for endothelial activation (hypoxia, inflammation), DNA repair and apoptosis, promoting an ageing-like phenotype; microgravity, unlike SR, activated pathways for metabolism and pro-proliferation phenotype. Thus, microgravity and SR should be considered separately to tailor effective countermeasures to protect astronauts’ health.