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Schulze A, Zimmermann A, Kainz K, Egger NB, Bauer MA, Madeo F, Carmona-Gutierrez D. Assessing chronological aging in Saccharomyces cerevisiae. Methods Cell Biol 2023; 181:87-108. [PMID: 38302246 DOI: 10.1016/bs.mcb.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Chronological age represents the time that passes between birth and a given date. To understand the complex network of factors contributing to chronological lifespan, a variety of model organisms have been implemented. One of the best studied organisms is the yeast Saccharomyces cerevisiae, which has greatly contributed toward identifying conserved biological mechanisms that act on longevity. Here, we discuss high- und low-throughput protocols to monitor and characterize chronological lifespan and chronological aging-associated cell death in S. cerevisiae. Included are propidium iodide staining with the possibility to quantitatively assess aging-associated cell death via flow cytometry or qualitative assessments via microscopy, cell viability assessment through plating and cell counting and cell death characterization via propidium iodide/AnnexinV staining and subsequent flow cytometric analysis or microscopy. Importantly, all of these methods combined give a clear picture of the chronological lifespan under different conditions or genetic backgrounds and represent a starting point for pharmacological or genetic interventions.
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Affiliation(s)
- Adina Schulze
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Andreas Zimmermann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Katharina Kainz
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Nadine B Egger
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Maria A Bauer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
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2
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Mukherjee M, Jana CK, Das N. Oxidation of biological molecules with age and induced oxidative stress in different growth phases of Saccharomyces cerevisiae. Antonie Van Leeuwenhoek 2023; 116:353-365. [PMID: 36749507 DOI: 10.1007/s10482-022-01807-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/30/2022] [Indexed: 02/08/2023]
Abstract
One of the mechanistic approaches for explaining ageing is the oxidative stress theory of ageing. Saccharomyces cerevisiae has been used as a model to study ageing due to many factors. We have attempted to investigate if the differential ability to withstand oxidative stress can be correlated with their lifespans. In all the four strains studied (AP22, 699, 8C, and SP4), there was no age-associated increases in lipid peroxidation levels measured as thiobarbituric acid reactive substances (TBARS). Under induced oxidative stress conditions, there was an increased TBARS level in both the ages assessed with a quantum-fold increase in the stationary phase cells of AP22. In contrast, the late stationary phase cells of 8C exhibited the least susceptibility to induced oxidative stress. The level of TBARS in both exponential and late stationary phase cells of 699 was overall more than that in the other three strains. Protein carbonylation increased with age in 8C and 699. Induced stress increased carbonylation in the exponential cells of SP4 and 699 and the stationary phase cells of all four strains. Protein carbonylation data indicate that the AP22 cells exhibit decreased protein carbonylation vis-à-vis the other strains. Induced stress data showed that while the exponential cells of 699 are susceptible, the late stationary phase cells of 699 are most resistant. Western blotting analysis using anti-HNE antibodies showed two proteins of molecular mass ~ 56 and ~ 84 kDa that were selectively modified with age in all the strains. Under induced stress conditions, an additional protein of ~ 69 kDa was oxidized. Our investigation shows that the difference in lifespan between the four strains of S. cerevisiae may be regulated by oxidative stress. Knowledge of the identity of the oxidized proteins will significantly facilitate a better understanding of the effect of oxidative stress conditions on the cells of S. cerevisiae.
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Affiliation(s)
- Madhumathan Mukherjee
- Department of Biotechnology, Visva-Bharati University, Santiniketan, West Bengal, 731235, India
- St. Teresa School, Santiniketan, Dist. Birbhum, 731235, India
| | - Chandan Kumar Jana
- Department of Chemistry, Purash-Kanpur Haridas Nandi Mahavidyalaya, P.O. Kanpur, Howrah, West Bengal, 711410, India
| | - Nilanjana Das
- Department of Biotechnology, Visva-Bharati University, Santiniketan, West Bengal, 731235, India.
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3
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Leonov A, Feldman R, Piano A, Arlia-Ciommo A, Junio JAB, Orfanos E, Tafakori T, Lutchman V, Mohammad K, Elsaser S, Orfali S, Rajen H, Titorenko VI. Diverse geroprotectors differently affect a mechanism linking cellular aging to cellular quiescence in budding yeast. Oncotarget 2022; 13:918-943. [PMID: 35937500 PMCID: PMC9348708 DOI: 10.18632/oncotarget.28256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/01/2022] [Indexed: 11/25/2022] Open
Affiliation(s)
- Anna Leonov
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Rachel Feldman
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Amanda Piano
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | | | | | - Emmanuel Orfanos
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Tala Tafakori
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Vicky Lutchman
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Karamat Mohammad
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Sarah Elsaser
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Sandra Orfali
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Harshvardhan Rajen
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
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4
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Kim HS. Disruption of YCP4 enhances freeze-thaw tolerance in Saccharomyces cerevisiae. Biotechnol Lett 2022; 44:503-511. [PMID: 35124760 DOI: 10.1007/s10529-022-03228-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/26/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study aimed to identify genes related to freeze-thaw tolerance and elucidate the tolerance mechanism in yeast Saccharomyces cerevisiae as an appropriate eukaryote model. RESULTS In this study, one tolerant strain exposed to freeze-thaw stress was isolated by screening a transposon-mediated mutant library and the disrupted gene was identified to be YCP4. In addition, this phenotype related to freeze-thaw tolerance was confirmed by deletion and overexpressing of this corresponding gene. This mutant strain showed a freeze-thaw tolerance by reducing the intracellular level of reactive oxygen species and the activation of the MSN2/4 and STRE-mediated genes such as CTT1 and HSP12. CONCLUSIONS Disruption of YCP4 in S. cerevisiae results in increased tolerance to freeze-thaw stress.
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Affiliation(s)
- Hyun-Soo Kim
- Department of Food Science and Technology, Jungwon University, 85, Munmu-ro, Goesan-eup, Goesan-gun, Chungbuk, 367-805, Republic of Korea.
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5
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Caloric restriction causes a distinct reorganization of the lipidome in quiescent and non-quiescent cells of budding yeast. Oncotarget 2021; 12:2351-2374. [PMID: 34853658 PMCID: PMC8629408 DOI: 10.18632/oncotarget.28133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022] Open
Abstract
After budding yeast cells cultured in a nutrient-rich liquid medium with 0.2% glucose (under caloric restriction conditions) or 2% glucose (under non-caloric restriction conditions), ferment glucose to ethanol and then consume ethanol, they enter the stationary phase. The process of their chronological aging begins. At that point, the yeast culture starts to accumulate quiescent and non-quiescent cells. Here, we purified the high- and low-density populations of quiescent and non-quiescent cells from the yeast cultures limited in calorie supply or not. We then employed mass spectrometry-based quantitative lipidomics to assess the aging-associated changes in high- and low-density cells’ lipidomes. We found that caloric restriction, a geroprotective dietary intervention, alters the concentrations of many lipid classes through most of the chronological lifespan of the high- and low-density populations of quiescent and non-quiescent cells. Specifically, caloric restriction decreased triacylglycerol, increased free fatty acid, elevated phospholipid and amplified cardiolipin concentrations. Based on these findings, we propose a hypothetical model for a caloric restriction-dependent reorganization of lipid metabolism in budding yeast’s quiescent and non-quiescent cells. We also discovered that caloric restriction creates lipidomic patterns of these cells that differ from those established by two other robust geroprotectors, namely the tor1Δ mutation and lithocholic acid.
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6
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Sun S, Gresham D. Cellular quiescence in budding yeast. Yeast 2021; 38:12-29. [PMID: 33350503 DOI: 10.1002/yea.3545] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022] Open
Abstract
Cellular quiescence, the temporary and reversible exit from proliferative growth, is the predominant state of all cells. However, our understanding of the biological processes and molecular mechanisms that underlie cell quiescence remains incomplete. As with the mitotic cell cycle, budding and fission yeast are preeminent model systems for studying cellular quiescence owing to their rich experimental toolboxes and the evolutionary conservation across eukaryotes of pathways and processes that control quiescence. Here, we review current knowledge of cell quiescence in budding yeast and how it pertains to cellular quiescence in other organisms, including multicellular animals. Quiescence entails large-scale remodeling of virtually every cellular process, organelle, gene expression, and metabolic state that is executed dynamically as cells undergo the initiation, maintenance, and exit from quiescence. We review these major transitions, our current understanding of their molecular bases, and highlight unresolved questions. We summarize the primary methods employed for quiescence studies in yeast and discuss their relative merits. Understanding cell quiescence has important consequences for human disease as quiescent single-celled microbes are notoriously difficult to kill and quiescent human cells play important roles in diseases such as cancer. We argue that research on cellular quiescence will be accelerated through the adoption of common criteria, and methods, for defining cell quiescence. An integrated approach to studying cell quiescence, and a focus on the behavior of individual cells, will yield new insights into the pathways and processes that underlie cell quiescence leading to a more complete understanding of the life cycle of cells. TAKE AWAY: Quiescent cells are viable cells that have reversibly exited the cell cycle Quiescence is induced in response to a variety of nutrient starvation signals Quiescence is executed dynamically through three phases: initiation, maintenance, and exit Quiescence entails large-scale remodeling of gene expression, organelles, and metabolism Single-cell approaches are required to address heterogeneity among quiescent cells.
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Affiliation(s)
- Siyu Sun
- Center for Genomics and Systems Biology, New York University, New York, New York, 10003, USA.,Department of Biology, New York University, New York, New York, 10003, USA
| | - David Gresham
- Center for Genomics and Systems Biology, New York University, New York, New York, 10003, USA.,Department of Biology, New York University, New York, New York, 10003, USA
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Santos SM, Laflin S, Broadway A, Burnet C, Hartheimer J, Rodgers J, Smith DL, Hartman JL. High-resolution yeast quiescence profiling in human-like media reveals complex influences of auxotrophy and nutrient availability. GeroScience 2020; 43:941-964. [PMID: 33015753 PMCID: PMC8110628 DOI: 10.1007/s11357-020-00265-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
Yeast cells survive in stationary phase culture by entering quiescence, which is measured by colony-forming capacity upon nutrient re-exposure. Yeast chronological lifespan (CLS) studies, employing the comprehensive collection of gene knockout strains, have correlated weakly between independent laboratories, which is hypothesized to reflect differential interaction between the deleted genes, auxotrophy, media composition, and other assay conditions influencing quiescence. This hypothesis was investigated by high-throughput quiescence profiling of the parental prototrophic strain, from which the gene deletion strain libraries were constructed, and all possible auxotrophic allele combinations in that background. Defined media resembling human cell culture media promoted long-term quiescence and was used to assess effects of glucose, ammonium sulfate, auxotrophic nutrient availability, target of rapamycin signaling, and replication stress. Frequent, high-replicate measurements of colony-forming capacity from cultures aged past 60 days provided profiles of quiescence phenomena such as gasping and hormesis. Media acidification was assayed in parallel to assess correlation. Influences of leucine, methionine, glucose, and ammonium sulfate metabolism were clarified, and a role for lysine metabolism newly characterized, while histidine and uracil perturbations had less impact. Interactions occurred between glucose, ammonium sulfate, auxotrophy, auxotrophic nutrient limitation, aeration, TOR signaling, and/or replication stress. Weak correlation existed between media acidification and maintenance of quiescence. In summary, experimental factors, uncontrolled across previous genome-wide yeast CLS studies, influence quiescence and interact extensively, revealing quiescence as a complex metabolic and developmental process that should be studied in a prototrophic context, omitting ammonium sulfate from defined media, and employing highly replicable protocols.
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Affiliation(s)
- Sean M Santos
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Samantha Laflin
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Audrie Broadway
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Cosby Burnet
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joline Hartheimer
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John Rodgers
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel L Smith
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John L Hartman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA.
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Mohammad K, Baratang Junio JA, Tafakori T, Orfanos E, Titorenko VI. Mechanisms that Link Chronological Aging to Cellular Quiescence in Budding Yeast. Int J Mol Sci 2020; 21:ijms21134717. [PMID: 32630624 PMCID: PMC7369985 DOI: 10.3390/ijms21134717] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/27/2020] [Accepted: 06/30/2020] [Indexed: 12/28/2022] Open
Abstract
After Saccharomyces cerevisiae cells cultured in a medium with glucose consume glucose, the sub-populations of quiescent and non-quiescent cells develop in the budding yeast culture. An age-related chronology of quiescent and non-quiescent yeast cells within this culture is discussed here. We also describe various hallmarks of quiescent and non-quiescent yeast cells. A complex aging-associated program underlies cellular quiescence in budding yeast. This quiescence program includes a cascade of consecutive cellular events orchestrated by an intricate signaling network. We examine here how caloric restriction, a low-calorie diet that extends lifespan and healthspan in yeast and other eukaryotes, influences the cellular quiescence program in S. cerevisiae. One of the main objectives of this review is to stimulate an exploration of the mechanisms that link cellular quiescence to chronological aging of budding yeast. Yeast chronological aging is defined by the length of time during which a yeast cell remains viable after its growth and division are arrested, and it becomes quiescent. We propose a hypothesis on how caloric restriction can slow chronological aging of S. cerevisiae by altering the chronology and properties of quiescent cells. Our hypothesis posits that caloric restriction delays yeast chronological aging by targeting four different processes within quiescent cells.
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9
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Opalek M, Wloch-Salamon D. Aspects of Multicellularity in Saccharomyces cerevisiae Yeast: A Review of Evolutionary and Physiological Mechanisms. Genes (Basel) 2020; 11:genes11060690. [PMID: 32599749 PMCID: PMC7349301 DOI: 10.3390/genes11060690] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/22/2020] [Accepted: 06/22/2020] [Indexed: 12/11/2022] Open
Abstract
The evolutionary transition from single-celled to multicellular growth is a classic and intriguing problem in biology. Saccharomyces cerevisiae is a useful model to study questions regarding cell aggregation, heterogeneity and cooperation. In this review, we discuss scenarios of group formation and how this promotes facultative multicellularity in S. cerevisiae. We first describe proximate mechanisms leading to aggregation. These mechanisms include staying together and coming together, and can lead to group heterogeneity. Heterogeneity is promoted by nutrient limitation, structured environments and aging. We then characterize the evolutionary benefits and costs of facultative multicellularity in yeast. We summarize current knowledge and focus on the newest state-of-the-art discoveries that will fuel future research programmes aiming to understand facultative microbial multicellularity.
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10
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Mohammad K, Dakik P, Medkour Y, Mitrofanova D, Titorenko VI. Quiescence Entry, Maintenance, and Exit in Adult Stem Cells. Int J Mol Sci 2019; 20:ijms20092158. [PMID: 31052375 PMCID: PMC6539837 DOI: 10.3390/ijms20092158] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/24/2019] [Accepted: 04/28/2019] [Indexed: 12/13/2022] Open
Abstract
Cells of unicellular and multicellular eukaryotes can respond to certain environmental cues by arresting the cell cycle and entering a reversible state of quiescence. Quiescent cells do not divide, but can re-enter the cell cycle and resume proliferation if exposed to some signals from the environment. Quiescent cells in mammals and humans include adult stem cells. These cells exhibit improved stress resistance and enhanced survival ability. In response to certain extrinsic signals, adult stem cells can self-renew by dividing asymmetrically. Such asymmetric divisions not only allow the maintenance of a population of quiescent cells, but also yield daughter progenitor cells. A multistep process of the controlled proliferation of these progenitor cells leads to the formation of one or more types of fully differentiated cells. An age-related decline in the ability of adult stem cells to balance quiescence maintenance and regulated proliferation has been implicated in many aging-associated diseases. In this review, we describe many traits shared by different types of quiescent adult stem cells. We discuss how these traits contribute to the quiescence, self-renewal, and proliferation of adult stem cells. We examine the cell-intrinsic mechanisms that allow establishing and sustaining the characteristic traits of adult stem cells, thereby regulating quiescence entry, maintenance, and exit.
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Affiliation(s)
- Karamat Mohammad
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Paméla Dakik
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Younes Medkour
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Darya Mitrofanova
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Vladimir I Titorenko
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
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11
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Sagot I, Laporte D. The cell biology of quiescent yeast – a diversity of individual scenarios. J Cell Sci 2019; 132:132/1/jcs213025. [DOI: 10.1242/jcs.213025] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
ABSTRACT
Most cells, from unicellular to complex organisms, spend part of their life in quiescence, a temporary non-proliferating state. Although central for a variety of essential processes including tissue homeostasis, development and aging, quiescence is poorly understood. In fact, quiescence encompasses various cellular situations depending on the cell type and the environmental niche. Quiescent cell properties also evolve with time, adding another layer of complexity. Studying quiescence is, above all, limited by the fact that a quiescent cell can be recognized as such only after having proved that it is capable of re-proliferating. Recent cellular biology studies in yeast have reported the relocalization of hundreds of proteins and the reorganization of several cellular machineries upon proliferation cessation. These works have revealed that quiescent cells can display various properties, shedding light on a plethora of individual behaviors. The deciphering of the molecular mechanisms beyond these reorganizations, together with the understanding of their cellular functions, have begun to provide insights into the physiology of quiescent cells. In this Review, we discuss recent findings and emerging concepts in Saccharomyces cerevisiae quiescent cell biology.
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Affiliation(s)
- Isabelle Sagot
- Centre National de la Recherche Scientifique, Université de Bordeaux-Institut de Biochimie et Génétique Cellulaires, UMR5095-33077 Bordeaux cedex, France
| | - Damien Laporte
- Centre National de la Recherche Scientifique, Université de Bordeaux-Institut de Biochimie et Génétique Cellulaires, UMR5095-33077 Bordeaux cedex, France
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12
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Laporte D, Gouleme L, Jimenez L, Khemiri I, Sagot I. Mitochondria reorganization upon proliferation arrest predicts individual yeast cell fate. eLife 2018; 7:35685. [PMID: 30299253 PMCID: PMC6177259 DOI: 10.7554/elife.35685] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 09/14/2018] [Indexed: 02/06/2023] Open
Abstract
Most cells spend the majority of their life in a non-proliferating state. When proliferation cessation is irreversible, cells are senescent. By contrast, if the arrest is only temporary, cells are defined as quiescent. These cellular states are hardly distinguishable without triggering proliferation resumption, hampering thus the study of quiescent cells properties. Here we show that quiescent and senescent yeast cells are recognizable based on their mitochondrial network morphology. Indeed, while quiescent yeast cells display numerous small vesicular mitochondria, senescent cells exhibit few globular mitochondria. This allowed us to reconsider at the individual-cell level, properties previously attributed to quiescent cells using population-based approaches. We demonstrate that cell’s propensity to enter quiescence is not influenced by replicative age, volume or density. Overall, our findings reveal that quiescent cells are not all identical but that their ability to survive is significantly improved when they exhibit the specific reorganization of several cellular machineries.
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Affiliation(s)
- Damien Laporte
- Centre National de la Recherche Scientifique, Université de Bordeaux - Institut de Biochimie et Génétique Cellulaires, Bordeaux, France
| | - Laëtitia Gouleme
- Centre National de la Recherche Scientifique, Université de Bordeaux - Institut de Biochimie et Génétique Cellulaires, Bordeaux, France
| | - Laure Jimenez
- Centre National de la Recherche Scientifique, Université de Bordeaux - Institut de Biochimie et Génétique Cellulaires, Bordeaux, France
| | - Ines Khemiri
- Centre National de la Recherche Scientifique, Université de Bordeaux - Institut de Biochimie et Génétique Cellulaires, Bordeaux, France
| | - Isabelle Sagot
- Centre National de la Recherche Scientifique, Université de Bordeaux - Institut de Biochimie et Génétique Cellulaires, Bordeaux, France
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13
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Mohammad K, Titorenko VI. Yeast chronological aging is linked to cell cycle regulation. Cell Cycle 2018; 17:1035-1036. [PMID: 29895227 DOI: 10.1080/15384101.2018.1478670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Karamat Mohammad
- a Department of Biology , Concordia University , Montreal , Canada
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14
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Dubinski AF, Camasta R, Soule TGB, Reed BH, Glerum DM. Consequences of cytochrome c oxidase assembly defects for the yeast stationary phase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:445-458. [PMID: 29567354 DOI: 10.1016/j.bbabio.2018.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/13/2018] [Accepted: 03/19/2018] [Indexed: 12/24/2022]
Abstract
The assembly of cytochrome c oxidase (COX) is essential for a functional mitochondrial respiratory chain, although the consequences of a loss of assembled COX at yeast stationary phase, an excellent model for terminally differentiated cells in humans, remain largely unexamined. In this study, we show that a wild-type respiratory competent yeast strain at stationary phase is characterized by a decreased oxidative capacity, as seen by a reduction in the amount of assembled COX and by a decrease in protein levels of several COX assembly factors. In contrast, loss of assembled COX results in the decreased abundance of many mitochondrial proteins at stationary phase, which is likely due to decreased membrane potential and changes in mitophagy. In addition to an altered mitochondrial proteome, COX assembly mutants display unexpected changes in markers of cellular oxidative stress at stationary phase. Our results suggest that mitochondria may not be a major source of reactive oxygen species at stationary phase in cells lacking an intact respiratory chain.
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Affiliation(s)
- Alicia F Dubinski
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Raffaele Camasta
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Tyler G B Soule
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Bruce H Reed
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - D Moira Glerum
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
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15
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Arlia-Ciommo A, Leonov A, Beach A, Richard VR, Bourque SD, Burstein MT, Kyryakov P, Gomez-Perez A, Koupaki O, Feldman R, Titorenko VI. Caloric restriction delays yeast chronological aging by remodeling carbohydrate and lipid metabolism, altering peroxisomal and mitochondrial functionalities, and postponing the onsets of apoptotic and liponecrotic modes of regulated cell death. Oncotarget 2018; 9:16163-16184. [PMID: 29662634 PMCID: PMC5882325 DOI: 10.18632/oncotarget.24604] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/25/2018] [Indexed: 01/08/2023] Open
Abstract
A dietary regimen of caloric restriction delays aging in evolutionarily distant eukaryotes, including the budding yeast Saccharomyces cerevisiae. Here, we assessed how caloric restriction influences morphological, biochemical and cell biological properties of chronologically aging yeast advancing through different stages of the aging process. Our findings revealed that this low-calorie diet slows yeast chronological aging by mechanisms that coordinate the spatiotemporal dynamics of various cellular processes before entry into a non-proliferative state and after such entry. Caloric restriction causes a stepwise establishment of an aging-delaying cellular pattern by tuning a network that assimilates the following: 1) pathways of carbohydrate and lipid metabolism; 2) communications between the endoplasmic reticulum, lipid droplets, peroxisomes, mitochondria and the cytosol; and 3) a balance between the processes of mitochondrial fusion and fission. Through different phases of the aging process, the caloric restriction-dependent remodeling of this intricate network 1) postpones the age-related onsets of apoptotic and liponecrotic modes of regulated cell death; and 2) actively increases the chance of cell survival by supporting the maintenance of cellular proteostasis. Because caloric restriction decreases the risk of cell death and actively increases the chance of cell survival throughout chronological lifespan, this dietary intervention extends longevity of chronologically aging yeast.
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Affiliation(s)
| | - Anna Leonov
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Adam Beach
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Vincent R Richard
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Simon D Bourque
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | | | - Pavlo Kyryakov
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | | | - Olivia Koupaki
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Rachel Feldman
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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16
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Density separation of quiescent yeast using iodixanol. Biotechniques 2017; 63:169-173. [PMID: 29048268 DOI: 10.2144/000114596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/30/2017] [Indexed: 11/23/2022] Open
Abstract
As yeast are starved of nutrients, they enter G0, a quiescent state. Quiescent yeast (Q) cells retain viability for extended periods of time and resume growth following supplementation of missing nutrients. As such, Q cells have become a valuable model for studying longevity and self-renewal of chronologically aged cells. Traditional isolation of Q cells involves a relatively long centrifugation time through a continuous density gradient. Here, we describe a rapid and cost-effective Q-cell isolation technique that uses a single-density, one-step gradient prepared from media containing iodixanol.
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17
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Leonov A, Feldman R, Piano A, Arlia-Ciommo A, Lutchman V, Ahmadi M, Elsaser S, Fakim H, Heshmati-Moghaddam M, Hussain A, Orfali S, Rajen H, Roofigari-Esfahani N, Rosanelli L, Titorenko VI. Caloric restriction extends yeast chronological lifespan via a mechanism linking cellular aging to cell cycle regulation, maintenance of a quiescent state, entry into a non-quiescent state and survival in the non-quiescent state. Oncotarget 2017; 8:69328-69350. [PMID: 29050207 PMCID: PMC5642482 DOI: 10.18632/oncotarget.20614] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 08/14/2017] [Indexed: 12/22/2022] Open
Abstract
A yeast culture grown in a nutrient-rich medium initially containing 2% glucose is not limited in calorie supply. When yeast cells cultured in this medium consume glucose, they undergo cell cycle arrest at a checkpoint in late G1 and differentiate into quiescent and non-quiescent cell populations. Studies of such differentiation have provided insights into mechanisms of yeast chronological aging under conditions of excessive calorie intake. Caloric restriction is an aging-delaying dietary intervention. Here, we assessed how caloric restriction influences the differentiation of chronologically aging yeast cultures into quiescent and non-quiescent cells, and how it affects their properties. We found that caloric restriction extends yeast chronological lifespan via a mechanism linking cellular aging to cell cycle regulation, maintenance of quiescence, entry into a non-quiescent state and survival in this state. Our findings suggest that caloric restriction delays yeast chronological aging by causing specific changes in the following: 1) a checkpoint in G1 for cell cycle arrest and entry into a quiescent state; 2) a growth phase in which high-density quiescent cells are committed to become low-density quiescent cells; 3) the differentiation of low-density quiescent cells into low-density non-quiescent cells; and 4) the conversion of high-density quiescent cells into high-density non-quiescent cells.
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Affiliation(s)
- Anna Leonov
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Rachel Feldman
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Amanda Piano
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | | | - Vicky Lutchman
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Masoumeh Ahmadi
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Sarah Elsaser
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Hana Fakim
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | | | - Asimah Hussain
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Sandra Orfali
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | | | | | - Leana Rosanelli
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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18
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Honigberg SM. Similar environments but diverse fates: Responses of budding yeast to nutrient deprivation. MICROBIAL CELL 2016; 3:302-328. [PMID: 27917388 PMCID: PMC5134742 DOI: 10.15698/mic2016.08.516] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diploid budding yeast (Saccharomyces cerevisiae) can adopt one
of several alternative differentiation fates in response to nutrient limitation,
and each of these fates provides distinct biological functions. When different
strain backgrounds are taken into account, these various fates occur in response
to similar environmental cues, are regulated by the same signal transduction
pathways, and share many of the same master regulators. I propose that the
relationships between fate choice, environmental cues and signaling pathways are
not Boolean, but involve graded levels of signals, pathway activation and
master-regulator activity. In the absence of large differences between
environmental cues, small differences in the concentration of cues may be
reinforced by cell-to-cell signals. These signals are particularly essential for
fate determination within communities, such as colonies and biofilms, where fate
choice varies dramatically from one region of the community to another. The lack
of Boolean relationships between cues, signaling pathways, master regulators and
cell fates may allow yeast communities to respond appropriately to the wide
range of environments they encounter in nature.
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Affiliation(s)
- Saul M Honigberg
- Division of Cell Biology and Biophysics, University of Missouri-Kansas City, 5007 Rockhill Rd, Kansas City MO 64110, USA
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19
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Sauer M, Mattanovich D. Non-genetic impact factors on chronological lifespan and stress resistance of baker's yeast. MICROBIAL CELL 2016; 3:232-235. [PMID: 28362008 PMCID: PMC5348990 DOI: 10.15698/mic2016.06.504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Survival under nutrient limitation is an essential feature of microbial cells, and it is defined by the chronological lifespan. We summarize recent findings, illustrating how crucial the choice of the experimental setup is for the interpretation of data in this field. Especially the impact of oxygen supply differs depending on the culture type, highlighting the differences of alternatives like the retentostat to classical batch cultures. Finally the importance of culture conditions on cell aging and survival in biotechnological processes is highlighted.
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Affiliation(s)
- Michael Sauer
- Department of Biotechnology, BOKU - VIBT, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria. ; Austrian Centre of Industrial Biotechnology, Muthgasse 11, 1190 Vienna, Austria
| | - Diethard Mattanovich
- Department of Biotechnology, BOKU - VIBT, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria. ; Austrian Centre of Industrial Biotechnology, Muthgasse 11, 1190 Vienna, Austria
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20
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Lee HY, Cheng KY, Chao JC, Leu JY. Differentiated cytoplasmic granule formation in quiescent and non-quiescent cells upon chronological aging. MICROBIAL CELL 2016; 3:109-119. [PMID: 28357341 PMCID: PMC5349021 DOI: 10.15698/mic2016.03.484] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Stationary phase cultures represent a complicated cell population comprising at
least two different cell types, quiescent (Q) and non-quiescent (NQ) cells. Q
and NQ cells have different lifespans and cell physiologies. However, less is
known about the organization of cytosolic protein structures in these two cell
types. In this study, we examined Q and NQ cells for the formation of several
stationary phase-prevalent granule structures including actin bodies, proteasome
storage granules, stress granules, P-bodies, the compartment for unconventional
protein secretion (CUPS), and Hsp42-associated stationary phase granules
(Hsp42-SPGs). Most of these structures preferentially form in NQ cells, except
for Hsp42-SPGs, which are enriched in Q cells. When nutrients are provided, NQ
cells enter mitosis less efficiently than Q cells, likely due to the time
requirement for reorganizing some granule structures. We observed that heat
shock-induced misfolded proteins often colocalize to Hsp42-SPGs, and Q cells
clear these protein aggregates more efficiently, suggesting that Hsp42-SPGs may
play an important role in the stress resistance of Q cells. Finally, we show
that the cell fate of NQ cells is largely irreversible even if they are allowed
to reenter mitosis. Our results reveal that the formation of different granule
structures may represent the early stage of cell type differentiation in yeast
stationary phase cultures.
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Affiliation(s)
- Hsin-Yi Lee
- Molecular and Cell Biology, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Academia Sinica, Taipei, Taiwan. ; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Yu Cheng
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan. ; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Jung-Chi Chao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Jun-Yi Leu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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21
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Handee W, Li X, Hall KW, Deng X, Li P, Benning C, Williams BL, Kuo MH. An Energy-Independent Pro-longevity Function of Triacylglycerol in Yeast. PLoS Genet 2016; 12:e1005878. [PMID: 26907989 PMCID: PMC4764362 DOI: 10.1371/journal.pgen.1005878] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/27/2016] [Indexed: 01/09/2023] Open
Abstract
Intracellular triacylglycerol (TAG) is a ubiquitous energy storage lipid also involved in lipid homeostasis and signaling. Comparatively, little is known about TAG’s role in other cellular functions. Here we show a pro-longevity function of TAG in the budding yeast Saccharomyces cerevisiae. In yeast strains derived from natural and laboratory environments a correlation between high levels of TAG and longer chronological lifespan was observed. Increased TAG abundance through the deletion of TAG lipases prolonged chronological lifespan of laboratory strains, while diminishing TAG biosynthesis shortened lifespan without apparently affecting vegetative growth. TAG-mediated lifespan extension was independent of several other known stress response factors involved in chronological aging. Because both lifespan regulation and TAG metabolism are conserved, this cellular pro-longevity function of TAG may extend to other organisms. Triacylglycerol (TAG) is a ubiquitous lipid species well-known for its roles in storing surplus energy, providing insulation, and maintaining cellular lipid homeostasis. Here we present evidence for a novel pro-longevity function of TAG in the budding yeast, a model organism for aging research. Yeast cells that are genetically engineered to store more TAG live significantly longer without suffering obvious growth defects, whereas those lean cells that are depleted of TAG die early. Yeast strains isolated from the wild in general contain more fat and also display longer lifespan. One of the approaches taken here to force the increase of intracellular TAG is to delete lipases responsible for lipid hydrolysis. Energy extraction from TAG thus is unlikely an underlying cause of the observed lifespan extension. Our results are reminiscent of certain animal studies linking higher body fat to longer lifespan. Potential mechanisms for the connection of TAG and yeast lifespan regulation are discussed.
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Affiliation(s)
- Witawas Handee
- Department of Cell and Molecular Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Xiaobo Li
- DOE-Plant Research Laboratory, Michigan State University. East Lansing, Michigan, United States of America
- Department of Plant Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Kevin W. Hall
- Department of Integrative Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Xiexiong Deng
- Department of Biochemistry and Molecular Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Pan Li
- Department of Biochemistry and Molecular Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Christoph Benning
- Department of Biochemistry and Molecular Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Barry L. Williams
- Department of Integrative Biology, Michigan State University. East Lansing, Michigan, United States of America
| | - Min-Hao Kuo
- Department of Biochemistry and Molecular Biology, Michigan State University. East Lansing, Michigan, United States of America
- * E-mail:
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22
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Kakolyri M, Margaritou A, Tiligada E. Dimethyl sulphoxide modifies growth and senescence and induces the non-revertible petite phenotype in yeast. FEMS Yeast Res 2016; 16:fow008. [PMID: 26833420 DOI: 10.1093/femsyr/fow008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2016] [Indexed: 11/12/2022] Open
Abstract
Dimethyl sulphoxide is extensively used in chemical, pharmaceutical and biomedical applications, but its specific biological actions remain largely elusive. The aim of this study was to comprehensively explore the effects of dimethyl sulphoxide on eukaryotic growth and senescence by using the budding yeast Saccharomyces cerevisiae as a reliable model organism. Rather than focusing on single cells or on either the replicative or the chronological lifespan approach, well-established microbiological procedures were integrated to monitor a combination of physiological parameters. Cell proliferation, survival, reproductive competence and morphology were recorded at various time points during incubation of asynchronous yeast populations with increasing concentrations of dimethyl sulphoxide. The findings demonstrated a dose-dependent inhibitory effect of the compound on yeast proliferation, survival and reproduction. In parallel, dimethyl sulphoxide induced the acquisition of the non-revertible petite phenotype and promoted morphological alterations that characterize senescence, driving the yeast populations towards the reproductive incompetent state. These findings point to the need for the investigation of the complex cellular and/or molecular mechanisms underlying the actions of dimethyl sulphoxide in eukaryotic cells and for the evaluation of their exploitation potential.
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Affiliation(s)
- Maria Kakolyri
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, GR-11527 Athens, Greece
| | - Aikaterini Margaritou
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, GR-11527 Athens, Greece
| | - Ekaterini Tiligada
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, GR-11527 Athens, Greece
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23
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Arlia-Ciommo A, Piano A, Leonov A, Svistkova V, Titorenko VI. Quasi-programmed aging of budding yeast: a trade-off between programmed processes of cell proliferation, differentiation, stress response, survival and death defines yeast lifespan. Cell Cycle 2015; 13:3336-49. [PMID: 25485579 PMCID: PMC4614525 DOI: 10.4161/15384101.2014.965063] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent findings suggest that evolutionarily distant organisms share the key features of the aging process and exhibit similar mechanisms of its modulation by certain genetic, dietary and pharmacological interventions. The scope of this review is to analyze mechanisms that in the yeast Saccharomyces cerevisiae underlie: (1) the replicative and chronological modes of aging; (2) the convergence of these 2 modes of aging into a single aging process; (3) a programmed differentiation of aging cell communities in liquid media and on solid surfaces; and (4) longevity-defining responses of cells to some chemical compounds released to an ecosystem by other organisms populating it. Based on such analysis, we conclude that all these mechanisms are programs for upholding the long-term survival of the entire yeast population inhabiting an ecological niche; however, none of these mechanisms is a ʺprogram of agingʺ - i.e., a program for progressing through consecutive steps of the aging process.
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Key Words
- D, diauxic growth phase
- ERCs, extrachromosomal rDNA circles
- IPOD, insoluble protein deposit
- JUNQ, juxtanuclear quality control compartment
- L, logarithmic growth phase
- MBS, the mitochondrial back-signaling pathway
- MTC, the mitochondrial translation control signaling pathway
- NPCs, nuclear pore complexes
- NQ, non-quiescent cells
- PD, post-diauxic growth phase
- Q, quiescent cells
- ROS, reactive oxygen species
- RTG, the mitochondrial retrograde signaling pathway
- Ras/cAMP/PKA, the Ras family GTPase/cAMP/protein kinase A signaling pathway
- ST, stationary growth phase
- TOR/Sch9, the target of rapamycin/serine-threonine protein kinase Sch9 signaling pathway
- UPRER, the unfolded protein response pathway in the endoplasmic reticulum
- UPRmt, the unfolded protein response pathway in mitochondria
- cell growth and proliferation
- cell survival
- cellular aging
- ecosystems
- evolution
- longevity
- programmed cell death
- yeast
- yeast colony
- yeast replicative and chronological aging
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24
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Uncoupling reproduction from metabolism extends chronological lifespan in yeast. Proc Natl Acad Sci U S A 2014; 111:E1538-47. [PMID: 24706810 DOI: 10.1073/pnas.1323918111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Studies of replicative and chronological lifespan in Saccharomyces cerevisiae have advanced understanding of longevity in all eukaryotes. Chronological lifespan in this species is defined as the age-dependent viability of nondividing cells. To date this parameter has only been estimated under calorie restriction, mimicked by starvation. Because postmitotic cells in higher eukaryotes often do not starve, we developed a model yeast system to study cells as they age in the absence of calorie restriction. Yeast cells were encapsulated in a matrix consisting of calcium alginate to form ∼3 mm beads that were packed into bioreactors and fed ad libitum. Under these conditions cells ceased to divide, became heat shock and zymolyase resistant, yet retained high fermentative capacity. Over the course of 17 d, immobilized yeast cells maintained >95% viability, whereas the viability of starving, freely suspended (planktonic) cells decreased to <10%. Immobilized cells exhibited a stable pattern of gene expression that differed markedly from growing or starving planktonic cells, highly expressing genes in glycolysis, cell wall remodeling, and stress resistance, but decreasing transcription of genes in the tricarboxylic acid cycle, and genes that regulate the cell cycle, including master cyclins CDC28 and CLN1. Stress resistance transcription factor MSN4 and its upstream effector RIM15 are conspicuously up-regulated in the immobilized state, and an immobilized rim15 knockout strain fails to exhibit the long-lived, growth-arrested phenotype, suggesting that altered regulation of the Rim15-mediated nutrient-sensing pathway plays an important role in extending yeast chronological lifespan under calorie-unrestricted conditions.
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25
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Huang X, Withers BR, Dickson RC. Sphingolipids and lifespan regulation. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:657-64. [PMID: 23954556 DOI: 10.1016/j.bbalip.2013.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/01/2013] [Accepted: 08/06/2013] [Indexed: 02/08/2023]
Abstract
Diseases including cancer, type 2 diabetes, cardiovascular and immune dysfunction and neurodegeneration become more prevalent as we age, and combined with the increase in average human lifespan, place an ever increasing burden on the health care system. In this chapter we focus on finding ways of modulating sphingolipids to prevent the development of age-associated diseases or delay their onset, both of which could improve health in elderly, fragile people. Reducing the incidence of or delaying the onset of diseases of aging has blossomed in the past decade because of advances in understanding signal transduction pathways and cellular processes, especially in model organisms, that are largely conserved in most eukaryotes and that can be modulated to reduce signs of aging and increase health span. In model organisms such interventions must also increase lifespan to be considered significant, but this is not a requirement for use in humans. The most encouraging interventions in model organisms involve lowering the concentration of one or more sphingolipids so as to reduce the activity of key signaling pathways, one of the most promising being the Target of Rapamycin Complex 1 (TORC1) protein kinase pathway. Other potential ways in which modulating sphingolipids may contribute to improving the health profile of the elderly is by reducing oxidative stresses, inflammatory responses and growth factor signaling. Lastly, perhaps the most interesting way to modulate sphingolipids and promote longevity is by lowering the activity of serine palmitoyltransferase, the first enzyme in the de novo sphingolipid biosynthesis pathway. Available data in yeasts and rodents are encouraging and as we gain insights into molecular mechanisms the strategies for improving human health by modulating sphingolipids will become more apparent. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Xinhe Huang
- Department of Molecular and Cellular Biochemistry and the Lucille Markey Cancer Center, University of Kentucky College of Medicine, 741 S. Limestone, Lexington, KY 40536, USA
| | - Bradley R Withers
- Department of Molecular and Cellular Biochemistry and the Lucille Markey Cancer Center, University of Kentucky College of Medicine, 741 S. Limestone, Lexington, KY 40536, USA
| | - Robert C Dickson
- Department of Molecular and Cellular Biochemistry and the Lucille Markey Cancer Center, University of Kentucky College of Medicine, 741 S. Limestone, Lexington, KY 40536, USA.
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26
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Webb KJ, Xu T, Park SK, Yates JR. Modified MuDPIT separation identified 4488 proteins in a system-wide analysis of quiescence in yeast. J Proteome Res 2013; 12:2177-84. [PMID: 23540446 DOI: 10.1021/pr400027m] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A modified multidimensional protein identification technology (MudPIT) separation was coupled to an LTQ Orbitrap Velos mass spectrometer and used to rapidly identify the near-complete yeast proteome from a whole cell tryptic digest. This modified online two-dimensional liquid chromatography separation consists of 39 strong cation exchange steps followed by a short 18.5 min reversed-phase (RP) gradient. A total of 4269 protein identifications were made from 4189 distinguishable protein families from yeast during log phase growth. The "Micro" MudPIT separation performed as well as a standard MudPIT separation in 40% less gradient time. The majority of the yeast proteome can now be routinely covered in less than a days' time with high reproducibility and sensitivity. The newly devised separation method was used to detect changes in protein expression during cellular quiescence in yeast. An enrichment in the GO annotations "oxidation reduction", "catabolic processing" and "cellular response to oxidative stress" was seen in the quiescent cellular fraction, consistent with their long-lived stress resistant phenotypes. Heterogeneity was observed in the stationary phase fraction with a less dense cell population showing reductions in KEGG pathway categories of "Ribosome" and "Proteasome", further defining the complex nature of yeast populations present during stationary phase growth. In total, 4488 distinguishable protein families were identified in all cellular conditions tested.
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Affiliation(s)
- Kristofor J Webb
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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27
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Fernandes RL, Carlquist M, Lundin L, Heins AL, Dutta A, Sørensen SJ, Jensen AD, Nopens I, Lantz AE, Gernaey KV. Cell mass and cell cycle dynamics of an asynchronous budding yeast population: Experimental observations, flow cytometry data analysis, and multi-scale modeling. Biotechnol Bioeng 2012; 110:812-26. [DOI: 10.1002/bit.24749] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/05/2012] [Indexed: 02/02/2023]
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