Project description:Histone modification affects life span in various organisms. The loss of Histone H3K36 methylation can shorten replicative life span in Saccharomyces cerevisiae. However, budding yeast, as a model organism for aging research, has replicative life span (RLS) and chronological life span (CLS). In this study, we showed that the loss of Histone H3K36 methylation can shorten CLS in Saccharomyces cerevisiae. We identified Ubc3/Bre1 mediates polyubiquitination of Set2 K25 and K530 at log phase and stationary phase, and Bre1 interacts with Ubc3 and Rad6 simultaneously. BRE1 knockout can stabilize Set2 protein to maintain H3K36me3 and regulate the transcription of aging related genes, such as DSE1/DSE2/SUN4/EGT2/SCW11. We also proved that Gcn5-mediated Set2 acetylation regulates Set2 protein stability and chronological aging. Altogether, our study showed that knockout of BRE1 and GCN5 regulate Set2 protein level by mediating the polyubiquitination of Set2 to influence the level of H3K36me3 and the transcription level of aging related genes enriched by H3K36me3, thereby extending the chronological life span.
Project description:In this study, we used Saccharomyces cerevisiae to investigate the effects of GRX deletion on yeast chronological life span (CLS). Deletion of Grx1 or Grx2 shortened yeast CLS. Quantitative proteomics revealed that GRX deletion increased cellular ROS levels to activate Ras/PKA signal pathway. Our results provided new insights into mechanisms underlying aging process.
Project description:Histone modification affects life span in various organisms. The loss of Histone H3K36 methylation can shorten replicative life span in Saccharomyces cerevisiae. However, budding yeast, as a model organism for aging research, has replicative life span (RLS) and chronological life span (CLS). In this study, we showed that the loss of Histone H3K36 methylation can shorten CLS in Saccharomyces cerevisiae. We identified Ubc3/Bre1 mediates polyubiquitination of Set2 K25 and K530 at log phase and stationary phase, and Bre1 interacts with Ubc3 and Rad6 simultaneously. BRE1 knockout can stabilize Set2 protein to maintain H3K36me3 and regulate the transcription of aging related genes, such as DSE1/DSE2/SUN4/EGT2/SCW11. We also proved that Gcn5-mediated Set2 acetylation regulates Set2 protein stability and chronological aging. Altogether, our study showed that knockout of BRE1 and GCN5 regulate Set2 protein level by mediating the polyubiquitination of Set2 to influence the level of H3K36me3 and the transcription level of aging related genes enriched by H3K36me3, thereby extending the chronological life span.
Project description:Saccharomyces cerevisiae is currently widely used as a model to study chronological aging of metazoan cells. Chronological aging is typically studied in aerobic stationary phase (SP) cultures, i.e. the final stage of batch cultures in which growth is arrested due to exogenous carbon source exhaustion. Survival of yeast cells in SP defines their chronological lifespan (CLS). S. cerevisiae SP cultures have strongly contributed to the understanding of cellular mechanisms involved in aging and indicated a key role for oxygen. Oxygen is the natural starting point for reactive oxygen species (ROS) that may both have malignant and beneficial effects on aging. In addition, oxygen allows yeast to grow on ethanol and organic acids formed during the initial respiro-fermentative growth phase on glucose. This post-diauxic phase is hallmarked by reduced growth rates, increased expression of genes involved in SP survival, and increased stress resistance. To date, the role of oxygen and respiration in aging has mostly been studied using respiratory deficient mutants, and respiration repressing agents. However, genetic or chemical interventions may result in unwanted side effects that influence survival in SP. We therefore followed a different approach to evaluate the impact of oxygen availability on yeast robustness in SP, i.e. its CLS and stress resistance, by using the capability of S. cerevisiae to grow under anaerobic conditions. A thorough physiological comparison of strictly anaerobic and aerobic SP cultures revealed that the presence of oxygen during growth and aging of S. cerevisiae strongly affects its energetic status, longevity and stress tolerance in a positive way. Combining the physiological data with genome-wide expression analysis revealed that the oxygen-dependent diauxic growth phase enabled the full induction of robustness in S. cerevisiae, and points to appropriate pre-conditioning of cells as a crucial factor to survive starvation. These findings highlight the importance of exogenous energy availability in the conditions leading to growth arrest, and bring new insight on the role of oxygen in the aging of eukaryotes. The goal of the present study is to evaluate the impact of oxygen availability on yeast longevity. More specifically, the questions addressed are whether the presence of a â??conditioningâ?? post-diauxic phase and the ability to utilize efficiently reserves, characteristics of aerobicity, affects yeast survival during stationary phase. To this end, S. cerevisiae was cultivated in well controlled bioreactors under the presence or absence of oxygen. S. cerevisiaeâ??s response to oxygen availability was monitored by an in-depth physiological analysis combined with genome wide expression analysis.
Project description:Target of rapamycin complex 1 (TORC1) is implicated in growth control and aging from yeast to humans. Fission yeast is emerging as a popular model organism to study TOR signaling, although rapamycin has been thought to not affect cell growth in this organism. Here we analyzed the effects of rapamycin and caffeine, singly and combined, on multiple cellular processes in fission yeast. The two drugs led to diverse and specific phenotypes that depended on TORC1 signaling pathway inhibition, including prolonged chronological lifespan, inhibition of global translation, inhibition of cell growth and division, and reprogramming of global gene expression mimicking nitrogen starvation. Rapamycin and caffeine differentially affected these various TORC1-dependent processes. Combined drug treatment augmented most phenotypes and effectively blocked cell growth. Although rapamycin showed a much more subtle effect on global translation than did caffeine, rapamycin was more effective in prolonging chronological lifespan. Rapamycin prolonged the lifespan of non-growing cells only when applied during the growth phase but not when applied after cells had stopped proliferation. The doses of rapamycin and caffeine strongly correlated with growth inhibition and with lifespan extension. This comprehensive analysis will inform future studies into TORC1 function and cellular aging in fission yeast and beyond.
Project description:Skeletal muscle is a post-mitotic tissue that exhibits an extremely low turnover in the absence of disease or injury. At the same time, muscle possesses remarkable regenerative capacity mediated by satellite cells (SCs) that reside in close association with individual myofibers, underneath the fiberM-bM-^@M-^Ys basal lamina. Consistent with the low turnover of the muscle, SCs in adult animals are mitotically quiescent and therefore provide an excellent model to study stem cell quiescence. As an organism grows older, the resident stem cells are exposed to a deteriorating environment and experience chronological aging. In stem cells with high turnover, the effects of chronological aging are superimposed upon the effects of the replicative aging that results from DNA replication and cell division. On the contrary, SCs experience minimal replicative aging due to their low turnover. They are thus a good model to study the consequence of chronological aging of quiescent stem cells. We have developed an isolation protocol to selectively enrich SCs by FACS from adult mice and applied the ChIP-seq technology to obtain H3K4me3, H3K27me3 and H3K36me3 from quiescent and activated SCs from young mice and from quiescent SCs from old mice. Our analysis aims to understand the chromatin features underlying stem cell properties such as quiecence and lineage-potency, and to understand how the chromatin structure of a quiescent stem cell pouplation changes with age. VCAM+/CD31-/CD45-/Sca1- quiescent satellite cells (QSCs) were isolated by FACS from hindlimb muscle of uninjured 2-3- or 22-24-month old mice and processed for ChIP-seq.
Project description:Saccharomyces cerevisiae is currently widely used as a model to study chronological aging of metazoan cells. Chronological aging is typically studied in aerobic stationary phase (SP) cultures, i.e. the final stage of batch cultures in which growth is arrested due to exogenous carbon source exhaustion. Survival of yeast cells in SP defines their chronological lifespan (CLS). S. cerevisiae SP cultures have strongly contributed to the understanding of cellular mechanisms involved in aging and indicated a key role for oxygen. Oxygen is the natural starting point for reactive oxygen species (ROS) that may both have malignant and beneficial effects on aging. In addition, oxygen allows yeast to grow on ethanol and organic acids formed during the initial respiro-fermentative growth phase on glucose. This post-diauxic phase is hallmarked by reduced growth rates, increased expression of genes involved in SP survival, and increased stress resistance. To date, the role of oxygen and respiration in aging has mostly been studied using respiratory deficient mutants, and respiration repressing agents. However, genetic or chemical interventions may result in unwanted side effects that influence survival in SP. We therefore followed a different approach to evaluate the impact of oxygen availability on yeast robustness in SP, i.e. its CLS and stress resistance, by using the capability of S. cerevisiae to grow under anaerobic conditions. A thorough physiological comparison of strictly anaerobic and aerobic SP cultures revealed that the presence of oxygen during growth and aging of S. cerevisiae strongly affects its energetic status, longevity and stress tolerance in a positive way. Combining the physiological data with genome-wide expression analysis revealed that the oxygen-dependent diauxic growth phase enabled the full induction of robustness in S. cerevisiae, and points to appropriate pre-conditioning of cells as a crucial factor to survive starvation. These findings highlight the importance of exogenous energy availability in the conditions leading to growth arrest, and bring new insight on the role of oxygen in the aging of eukaryotes.
Project description:Age-related physiological decline emerges at different chronological ages across individuals. We compared mice that exhibited early or delayed hematopoietic aging at the same chronological age by scRNA-seq.
Project description:We investigated the chromatin accessibility of primary human adipose-derived stem cells (ASCs) and fibroblasts during chronological aging using ATAC-seq technology. our data suggest a significant role for nucleosome positioning in sumoylation pathway regulation in response to stress during aging of adult stem cells.