Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Time-course expression data during assurance of the chronological longevity by caloric restriction in budding yeast

ABSTRACT: Caloric restriction (CR) is the only non-genetic intervention to retard aging and increase longevity in a variety of species. It is important to understand the fundamental mechanism by which CR extends lifespan that remains elusive. Owing to well-established genomic tools and convenience of culture system, we used a single cell organism, Saccharomyces cerevisiae, to clarify the mechanisms of CR. In order to identify genes responsible for CR-mediated longevity, we performed microarray experiments across the longevity assurance time-points. Since the CR-treated cells obtained the longevity potential around 12 hours after inoculation and the strength of potential gradually increased up to 48 hours, we concluded that the changes across these time-points must be a critical need for assurance of longevity by CR. For preparation of total RNA, yeast cells under control (2% glucose) and CR (0.5% glucose) conditions were harvested at 12h, 18h, 24h and 48h after inoculation. After total RNA extraction, we performed Affymetrix Yeast GeneChip 2.0 array for biological triplicate repeats according to the manufacturer's instructions.

ORGANISM(S): Saccharomyces cerevisiae BY4741

SUBMITTER: Cheol-Koo Lee

PROVIDER: E-GEOD-41860 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

Project description:Studies using yeast have advanced our understanding of both replicative and chronological aging, leading to the discovery of longevity genes that have homologues in higher eukaryotes. Chronological lifespan in yeast is conventionally defined as the lifespan of a non-dividing cell. To date, this parameter has only been estimated under calorically restricted (CR) conditions, mimicked by starvation. Since post-mitotic cells in higher eukaryotes are rarely calorically-restricted, we sought to develop an alternative experimental system where non-dividing yeast would age chronologically, in the presence of excess nutrients. We report here on a system wherein alginate-encapsulated yeast are packed in a pH- and temperature-controlled bioreactor, then continuously fed non-limiting substrate for extended periods of time. We present demographic, physiological and genomic evidence indicating that after ~120 hrs, immobilized cells cease dividing, remain metabolically very active and retain >95% viability for periods of 17 days. Over the same time interval, starved planktonic cells, cultured using the same media, and also controlled for temperature and pH, retained < 1 % viability in both aerobic and anaerobic cultures,. Unlike planktonic yeast, continuously-fed immobilized cells hyper-accumulate glycogen. FACS analysis of SYTOX green-stained yeast confirms that immobilized cells completely arrest within 5 days of culture, and unlike starving planktonic cells, remain free thereafter of replicative stress and are non-apoptotic. This unusual state is supported by a global gene expression profile that is stable over time, repeatable across replicate experiments, and altogether distinct from planktonic cells cultured in the presence and absence of limiting nutrients. DNA expression profiling, performed here for the very first time on immobilized cells, reveals that glycolytic genes and their trans-acting regulatory elements are upregulated, as are genes involved in remodeling the cell wall and resisting stress; by contrast, many genes that promote cell cycle progression and carry out oxidative metabolism are repressed. Stress resistance transcription factor MSN4 and its upstream effector RIM15 are conspicuously upregulated in the immobilized state, suggesting that nutrient-sensing pathways may play a role in cell viability and longevity when yeast are immobilized and placed in prolonged culture under calorically-unrestricted conditions. The cell cycle arrest in the immobilized state is mediated by RIM 15. Over the time-course of our experiments, well-fed, non-diving immobilized cells do not appear to age. Keywords: comparison of growth states and a time course of immobilized cells Nine growth conditions or time points with two to four replicates each

Project description:The chronological lifespan (CLS) of Saccharomyces cerevisiae is defined as the number days that non-dividing cells remain viable, typically in stationary phase cultures or in water. CLS is extended by restricting glucose in the starting cultures, and is considered a form of caloric restriction (CR). Through a previous genetic screen our lab determined that deleting components of the de novo purine biosynthesis pathway also significantly increased CLS. Significant similarities in gene expression profiles between calorie restricted WT cells and a non-restricted ade4M-bM-^HM-^F mutant suggested the possibility of common gene expression biomarkers of all chronologically long lived cells that could also provide insights into general mechanisms of lifespan extension. We have identified additional growth conditions that extend CLS of WT cells, including supplementation of the media with isonicotinamide (INAM), a known sirtuin activator, or by supplementation with a concentrate collected from the expired media of a calorie restricted yeast culture, presumably due to an as yet unidentified longevity factor. Using these varied methods to extend CLS, we compared gene expression profiles in the aging cells (at day 8) to identify functionally relevant biomarkers of longevity. Nineteen genes were differentially regulated in all 4 of the long-lived populations relative to wild type. Of these 19 genes, viable haploid deletion mutants were available for 16 of them, and 12 were found to have a significant impact on CLS. Duplicate cultures were grown to saturation in SC media cultures, aged, and then harvested on day 8. The deletion mutant ade4M-bM-^HM-^F as well as WT cells treated with 25 mM isonicotinamide, calorie restricted (0.5% glucose), or treated with expired media concentrate from previously calorie restricted cultures. These 4 conditions were then compared to a wild-type (WT) strain. Total RNA was isolated and used for microarray hybridizations onto Affymetrix Yeast 2.0 Gene arrrays.

Dataset Information

Time-course expression data during assurance of the chronological longevity by caloric restriction in budding yeast

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure