1
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Deb R, Nagotu S. The nexus between peroxisome abundance and chronological ageing in Saccharomyces cerevisiae. Biogerontology 2023; 24:81-97. [PMID: 36209442 DOI: 10.1007/s10522-022-09992-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/23/2022] [Indexed: 01/20/2023]
Abstract
Ageing is characterized by changes in several cellular processes, with dysregulation of peroxisome function being one of them. Interestingly, the most conserved function of peroxisomes, ROS homeostasis, is strongly associated with ageing and age-associated pathologies. Previous studies have identified a role for peroxisomes in the regulation of chronological lifespan in yeast. In this study, we report the effect of altered peroxisome number on the chronological lifespan of yeast in two different growth media conditions. Three mutants, pex11, pex25 and pex27, defective in peroxisome fission, have been thoroughly investigated for the chronological lifespan. Reduced chronological lifespan of all the mutants was observed in peroxisome-inducing growth conditions. Furthermore, the combined deletion pex11pex25 exhibited the most prominent reduction in lifespan. Interestingly altered peroxisomal phenotype upon ageing was observed in all the cells. Increased ROS accumulation and reduced catalase activity was exhibited by chronologically aged mutant cells. Interestingly, mutants with reduced number of peroxisomes concomitantly also exhibited an accumulation of free fatty acids and increased number of lipid droplets. Taken together, our results reveal a previously unrealized effect of fission proteins in the chronological lifespan of yeast.
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Affiliation(s)
- Rachayeeta Deb
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
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2
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Natural Deep Eutectic Extracts of Propolis, Sideritis scardica, and Plantago major Reveal Potential Antiageing Activity during Yeast Chronological Lifespan. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:8368717. [PMID: 36082083 PMCID: PMC9448591 DOI: 10.1155/2022/8368717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/05/2022] [Indexed: 11/18/2022]
Abstract
Nowadays, the environmentally friendly approach to everyday life routines including body supplementation with pharma-, nutraceuticals and dietary supplements gains popularity. This trend is implemented in pharmaceutical as well as cosmetic and antiageing industries by adopting a newly developed green chemistry approach. Following this trend, a new type of solvents has been created, called Natural Deep Eutectic Solvents (NADES), which are produced by plant primary metabolites. These solvents are becoming a much better alternative to the already established organic solvents like ethanol and ionic liquids by being nontoxic, biodegradable, and easy to make. An interesting fact about NADES is that they enhance the biological activities of the extracted biological compounds. Here, we present our results that investigate the potential antiageing effect of CiAPD14 as a NADES solvent and three plant extracts with it. The tested NADES extracts are from propolis and two well-known medicinal plants—Sideritis scardica and Plantago major. Together with the solvent, their antiageing properties have been tested during the chronological lifespan of four Saccharomyces cerevisiae yeast strains—a wild type and three chromatin mutants. The chromatin mutants have been previously proven to exhibit characteristics of premature ageing. Our results demonstrate the potential antiageing activity of these NADES extracts, which was exhibited through their ability to confer the premature ageing phenotypes in the mutant cells by ameliorating their cellular growth and cell cycle, as well as by influencing the activity of some stress-responsive genes. Moreover, we have classified their antiageing activity concerning the strength of the observed bioactivities.
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3
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Increased peroxisome proliferation is associated with early yeast replicative ageing. Curr Genet 2022; 68:207-225. [DOI: 10.1007/s00294-022-01233-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 11/03/2022]
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4
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Kasselimi E, Pefani DE, Taraviras S, Lygerou Z. Ribosomal DNA and the nucleolus at the heart of aging. Trends Biochem Sci 2022; 47:328-341. [DOI: 10.1016/j.tibs.2021.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/15/2022]
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5
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Fiorillo M, Ózsvári B, Sotgia F, Lisanti MP. High ATP Production Fuels Cancer Drug Resistance and Metastasis: Implications for Mitochondrial ATP Depletion Therapy. Front Oncol 2021; 11:740720. [PMID: 34722292 PMCID: PMC8554334 DOI: 10.3389/fonc.2021.740720] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/07/2021] [Indexed: 12/25/2022] Open
Abstract
Recently, we presented evidence that high mitochondrial ATP production is a new therapeutic target for cancer treatment. Using ATP as a biomarker, we isolated the “metabolically fittest” cancer cells from the total cell population. Importantly, ATP-high cancer cells were phenotypically the most aggressive, with enhanced stem-like properties, showing multi-drug resistance and an increased capacity for cell migration, invasion and spontaneous metastasis. In support of these observations, ATP-high cells demonstrated the up-regulation of both mitochondrial proteins and other protein biomarkers, specifically associated with stemness and metastasis. Therefore, we propose that the “energetically fittest” cancer cells would be better able to resist the selection pressure provided by i) a hostile micro-environment and/or ii) conventional chemotherapy, allowing them to be naturally-selected for survival, based on their high ATP content, ultimately driving tumor recurrence and distant metastasis. In accordance with this energetic hypothesis, ATP-high MDA-MB-231 breast cancer cells showed a dramatic increase in their ability to metastasize in a pre-clinical model in vivo. Conversely, metastasis was largely prevented by treatment with an FDA-approved drug (Bedaquiline), which binds to and inhibits the mitochondrial ATP-synthase, leading to ATP depletion. Clinically, these new therapeutic approaches could have important implications for preventing treatment failure and avoiding cancer cell dormancy, by employing ATP-depletion therapy, to target even the fittest cancer cells.
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Affiliation(s)
- Marco Fiorillo
- Translational Medicine, School of Science, Engineering and Environment (SEE), University of Salford, Greater Manchester, United Kingdom.,The Department of Pharmacy, Health and Nutritional Sciences, The University of Calabria, Cosenza, Italy
| | - Béla Ózsvári
- Translational Medicine, School of Science, Engineering and Environment (SEE), University of Salford, Greater Manchester, United Kingdom
| | - Federica Sotgia
- Translational Medicine, School of Science, Engineering and Environment (SEE), University of Salford, Greater Manchester, United Kingdom
| | - Michael P Lisanti
- Translational Medicine, School of Science, Engineering and Environment (SEE), University of Salford, Greater Manchester, United Kingdom
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Moradi‐Fard S, Mojumdar A, Chan M, Harkness TA, Cobb JA. Smc5/6 in the rDNA modulates lifespan independently of Fob1. Aging Cell 2021; 20:e13373. [PMID: 33979898 PMCID: PMC8208791 DOI: 10.1111/acel.13373] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/18/2021] [Accepted: 04/08/2021] [Indexed: 12/28/2022] Open
Abstract
The ribosomal DNA (rDNA) in Saccharomycescerevisiae is in one tandem repeat array on Chromosome XII. Two regions within each repetitive element, called intergenic spacer 1 (IGS1) and IGS2, are important for organizing the rDNA within the nucleolus. The Smc5/6 complex localizes to IGS1 and IGS2. We show that Smc5/6 has a function in the rDNA beyond its role in homologous recombination (HR) at the replication fork barrier (RFB) located in IGS1. Fob1 is required for optimal binding of Smc5/6 at IGS1 whereas the canonical silencing factor Sir2 is required for its optimal binding at IGS2, independently of Fob1. Through interdependent interactions, Smc5/6 stabilizes Sir2 and Cohibin at both IGS and its recovery at IGS2 is important for nucleolar compaction and transcriptional silencing, which in turn supports rDNA stability and lifespan.
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Affiliation(s)
- Sarah Moradi‐Fard
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| | - Aditya Mojumdar
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| | - Megan Chan
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| | - Troy A.A. Harkness
- Department of Biochemistry, Microbiology and Immunology University of Saskatchewan Saskatoon SK Canada
| | - Jennifer A. Cobb
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
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7
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Plummer JD, Postnikoff SD, Tyler JK, Johnson JE. Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice. eLife 2021; 10:62483. [PMID: 33783357 PMCID: PMC8009673 DOI: 10.7554/elife.62483] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/16/2021] [Indexed: 12/14/2022] Open
Abstract
Methionine restriction (MR) dramatically extends the healthspan of several organisms. Methionine-restricted rodents have less age-related pathology and increased longevity as compared with controls, and recent studies suggest that humans might benefit similarly. Mechanistically, it is likely that the decreased IGF-1 signaling that results from MR underlies the benefits of this regimen. Thus, we hypothesized that interventions that decrease IGF-1 signaling would also produce MR-like healthspan benefits. Selenium supplementation inhibits IGF-1 signaling in rats and has been studied for its putative healthspan benefits. Indeed, we show that feeding mice a diet supplemented with sodium selenite results in an MR-like phenotype, marked by protection against diet-induced obesity, as well as altered plasma levels of IGF-1, FGF-21, adiponectin, and leptin. Selenomethionine supplementation results in a similar, albeit less robust response, and also extends budding yeast lifespan. Our results indicate that selenium supplementation is sufficient to produce MR-like healthspan benefits for yeast and mammals.
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Affiliation(s)
- Jason D Plummer
- Department of Biology, Orentreich Foundation for the Advancement of Science, Cold Spring, United States
| | - Spike Dl Postnikoff
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
| | - Jessica K Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
| | - Jay E Johnson
- Department of Biology, Orentreich Foundation for the Advancement of Science, Cold Spring, United States
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8
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Durán DC, Hernández CA, Suesca E, Acevedo R, Acosta IM, Forero DA, Rozo FE, Pedraza JM. Slipstreaming Mother Machine: A Microfluidic Device for Single-Cell Dynamic Imaging of Yeast. MICROMACHINES 2020; 12:mi12010004. [PMID: 33374994 PMCID: PMC7822021 DOI: 10.3390/mi12010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023]
Abstract
The yeast Saccharomyces cerevisiae is one of the most basic model organisms for studies of aging and other phenomena such as division strategies. These organisms have been typically studied with the use of microfluidic devices to keep cells trapped while under a flow of fresh media. However, all of the existing devices trap cells mechanically, subjecting them to pressures that may affect cell physiology. There is evidence mechanical pressure affects growth rate and the movement of intracellular components, so it is quite possible that it affects other physiological aspects such as aging. To allow studies with the lowest influence of mechanical pressure, we designed and fabricated a device that takes advantage of the slipstreaming effect. In slipstreaming, moving fluids that encounter a barrier flow around it forming a pressure gradient behind it. We trap mother cells in this region and force daughter cells to be in the negative pressure gradient region so that they are taken away by the flow. Additionally, this device can be fabricated using low resolution lithography techniques, which makes it less expensive than devices that require photolithography masks with resolution under 5 µm. With this device, it is possible to measure some of the most interesting aspects of yeast dynamics such as growth rates and Replicative Life Span. This device should allow future studies to eliminate pressure bias as well as extending the range of labs that can do these types of measurements.
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Affiliation(s)
- David C. Durán
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Correspondence: (D.C.D.); (J.M.P.); Tel.: +57-1-3394949 (ext. 5179 (COL)) (J.M.P.)
| | - César A. Hernández
- Centro de Microelectrónica, Departamento de Ingeniería Eléctrica y Electrónica, Universidad de los Andes CMUA, Bogotá 111711, Colombia;
| | - Elizabeth Suesca
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
| | - Rubén Acevedo
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
| | - Ivón M. Acosta
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Proyecto Curricular Licenciatura en Física, Facultad de Ciencias y Educación, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
| | - Diana A. Forero
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Proyecto Curricular Licenciatura en Física, Facultad de Ciencias y Educación, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
| | - Francisco E. Rozo
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Proyecto Curricular Licenciatura en Física, Facultad de Ciencias y Educación, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
| | - Juan M. Pedraza
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Correspondence: (D.C.D.); (J.M.P.); Tel.: +57-1-3394949 (ext. 5179 (COL)) (J.M.P.)
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9
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Prada-Luengo I, Møller HD, Henriksen RA, Gao Q, Larsen C, Alizadeh S, Maretty L, Houseley J, Regenberg B. Replicative aging is associated with loss of genetic heterogeneity from extrachromosomal circular DNA in Saccharomyces cerevisiae. Nucleic Acids Res 2020; 48:7883-7898. [PMID: 32609810 PMCID: PMC7430651 DOI: 10.1093/nar/gkaa545] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 05/28/2020] [Accepted: 06/17/2020] [Indexed: 12/26/2022] Open
Abstract
Circular DNA can arise from all parts of eukaryotic chromosomes. In yeast, circular ribosomal DNA (rDNA) accumulates dramatically as cells age, however little is known about the accumulation of other chromosome-derived circles or the contribution of such circles to genetic variation in aged cells. We profiled circular DNA in Saccharomyces cerevisiae populations sampled when young and after extensive aging. Young cells possessed highly diverse circular DNA populations but 94% of the circular DNA were lost after ∼15 divisions, whereas rDNA circles underwent massive accumulation to >95% of circular DNA. Circles present in both young and old cells were characterized by replication origins including circles from unique regions of the genome and repetitive regions: rDNA and telomeric Y' regions. We further observed that circles can have flexible inheritance patterns: [HXT6/7circle] normally segregates to mother cells but in low glucose is present in up to 50% of cells, the majority of which must have inherited this circle from their mother. Interestingly, [HXT6/7circle] cells are eventually replaced by cells carrying stable chromosomal HXT6 HXT6/7 HXT7 amplifications, suggesting circular DNAs are intermediates in chromosomal amplifications. In conclusion, the heterogeneity of circular DNA offers flexibility in adaptation, but this heterogeneity is remarkably diminished with age.
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Affiliation(s)
- Iñigo Prada-Luengo
- Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Henrik D Møller
- Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen DK-2100, Denmark
- Department of Biology, Institute of Biochemistry, ETH Zürich, Zurich CH-8093, Switzerland
| | - Rasmus A Henriksen
- Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Qian Gao
- Epigenetics Programme, The Babraham Institute, Babraham, Cambridge CB22 3-AT, UK
- Adaptimmune Ltd, Oxfordshire OX14 4RX, UK
| | - Camilla Eggert Larsen
- Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Sefa Alizadeh
- Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Lasse Maretty
- Department of Molecular Medicine, Aarhus University Hospital, Aarhus DK-8200, Denmark
| | - Jonathan Houseley
- Epigenetics Programme, The Babraham Institute, Babraham, Cambridge CB22 3-AT, UK
| | - Birgitte Regenberg
- Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen DK-2100, Denmark
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10
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Cell organelles and yeast longevity: an intertwined regulation. Curr Genet 2019; 66:15-41. [PMID: 31535186 DOI: 10.1007/s00294-019-01035-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 12/16/2022]
Abstract
Organelles are dynamic structures of a eukaryotic cell that compartmentalize various essential functions and regulate optimum functioning. On the other hand, ageing is an inevitable phenomenon that leads to irreversible cellular damage and affects optimum functioning of cells. Recent research shows compelling evidence that connects organelle dysfunction to ageing-related diseases/disorders. Studies in several model systems including yeast have led to seminal contributions to the field of ageing in uncovering novel pathways, proteins and their functions, identification of pro- and anti-ageing factors and so on. In this review, we present a comprehensive overview of findings that highlight the role of organelles in ageing and ageing-associated functions/pathways in yeast.
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Yeast at the Forefront of Research on Ageing and Age-Related Diseases. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2019; 58:217-242. [PMID: 30911895 DOI: 10.1007/978-3-030-13035-0_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ageing is a complex and multifactorial process driven by genetic, environmental and stochastic factors that lead to the progressive decline of biological systems. Mechanisms of ageing have been extensively investigated in various model organisms and systems generating fundamental advances. Notably, studies on yeast ageing models have made numerous and relevant contributions to the progress in the field. Different longevity factors and pathways identified in yeast have then been shown to regulate molecular ageing in invertebrate and mammalian models. Currently the best candidates for anti-ageing drugs such as spermidine and resveratrol or anti-ageing interventions such as caloric restriction were first identified and explored in yeast. Yeasts have also been instrumental as models to study the cellular and molecular effects of proteins associated with age-related diseases such as Parkinson's, Huntington's or Alzheimer's diseases. In this chapter, a review of the advances on ageing and age-related diseases research in yeast models will be made. Particular focus will be placed on key longevity factors, ageing hallmarks and interventions that slow ageing, both yeast-specific and those that seem to be conserved in multicellular organisms. Their impact on the pathogenesis of age-related diseases will be also discussed.
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12
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Smith JT, White JW, Dungrawala H, Hua H, Schneider BL. Yeast lifespan variation correlates with cell growth and SIR2 expression. PLoS One 2018; 13:e0200275. [PMID: 29979754 PMCID: PMC6034835 DOI: 10.1371/journal.pone.0200275] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/22/2018] [Indexed: 11/19/2022] Open
Abstract
Isogenic wild type yeast cells raised in controlled environments display a significant range of lifespan variation. Recent microfluidic studies suggest that differential growth or gene expression patterns may explain some of the heterogeneity of aging assays. Herein, we sought to complement this work by similarly examining a large set of replicative lifespan data from traditional plate assays. In so doing, we reproduced the finding that short-lived cells tend to arrest at senescence with a budded morphology. Further, we found that wild type cells born unusually small did not have an extended lifespan. However, large birth size and/or high inter-generational growth rates significantly correlated with a reduced lifespan. Finally, we found that SIR2 expression levels correlated with lifespan and intergenerational growth. SIR2 expression was significantly reduced in large cells and increased in small wild type cells. A moderate increase in SIR2 expression correlated with reduced growth, decreased proliferation and increased lifespan in plate aging assays. We conclude that cellular growth rates and SIR2 expression levels may contribute to lifespan variation in individual cells.
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Affiliation(s)
- Jessica T. Smith
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States of America
| | - Jill W. White
- Center for the Integration of STEM Education & Research, Texas Tech University, Lubbock, TX, United States of America
| | - Huzefa Dungrawala
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States of America
| | - Hui Hua
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States of America
| | - Brandt L. Schneider
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States of America
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13
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Barker MG, Smart KA. Morphological Changes Associated with the Cellular Aging of a Brewing Yeast Strain. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-54-0121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Michael G. Barker
- School of Biological and Molecular Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford 0X3 OBP U.K
| | - Katherine A. Smart
- School of Biological and Molecular Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford 0X3 OBP U.K
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14
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Maskell DL, Kennedy AI, Hodgson JA, Smart KA. Impact of Carbohydrate Composition of Media on Lager Yeast Replicative Lifespan. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-59-0111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Dawn L. Maskell
- School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP, UK
| | - Alan I. Kennedy
- Scottish Courage Brewing Limited, Technical Centre, Edinburgh, EH8 8DD, UK
| | - Jeff A. Hodgson
- Scottish Courage Brewing Limited, Technical Centre, Edinburgh, EH8 8DD, UK
| | - Katherine A. Smart
- School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP, UK
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15
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Tyler JK, Johnson JE. The role of autophagy in the regulation of yeast life span. Ann N Y Acad Sci 2018; 1418:31-43. [PMID: 29363766 DOI: 10.1111/nyas.13549] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 01/07/2023]
Abstract
The goal of the aging field is to develop novel therapeutic interventions that extend human health span and reduce the burden of age-related disease. While organismal aging is a complex, multifactorial process, a popular theory is that cellular aging is a significant contributor to the progressive decline inherent to all multicellular organisms. To explore the molecular determinants that drive cellular aging, as well as how to retard them, researchers have utilized the highly genetically tractable budding yeast Saccharomyces cerevisiae. Indeed, every intervention known to extend both cellular and organismal health span was identified in yeast, underlining the power of this approach. Importantly, a growing body of work has implicated the process of autophagy as playing a critical role in the delay of aging. This review summarizes recent reports that have identified a role for autophagy, or autophagy factors in the extension of yeast life span. These studies demonstrate (1) that yeast remains an invaluable tool for the identification and characterization of conserved mechanisms that promote cellular longevity and are likely to be relevant to humans, and (2) that the process of autophagy has been implicated in nearly all known longevity-promoting manipulations and thus represents an ideal target for interventions aimed at improving human health span.
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Affiliation(s)
- Jessica K Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York
| | - Jay E Johnson
- Department of Biology, Orentreich Foundation for the Advancement of Science, Cold Spring, New York
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16
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Zandveld J, van den Heuvel J, Mulder M, Brakefield PM, Kirkwood TBL, Shanley DP, Zwaan BJ. Pervasive gene expression responses to a fluctuating diet in Drosophila melanogaster: The importance of measuring multiple traits to decouple potential mediators of life span and reproduction. Evolution 2017; 71:2572-2583. [PMID: 28833068 DOI: 10.1111/evo.13327] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 01/08/2023]
Abstract
Phenotypic plasticity is an important concept in life-history evolution, and most organisms, including Drosophila melanogaster, show a plastic life-history response to diet. However, little is known about how these life-history responses are mediated. In this study, we compared adult female flies fed an alternating diet (yoyo flies) with flies fed a constant low (CL) or high (CH) diet and tested how whole genome expression was affected by these diet regimes and how the transcriptional responses related to different life-history traits. We showed that flies were able to respond quickly to diet fluctuations throughout life span by drastically changing their transcription. Importantly, by measuring the response of multiple life-history traits we were able to decouple groups of genes associated with life span or reproduction, life-history traits that often covary with a diet change. A coexpression network analysis uncovered which genes underpin the separate and shared regulation of these life-history traits. Our study provides essential insights to help unravel the genetic architecture mediating life-history responses to diet, and it shows that the flies' whole genome transcription response is highly plastic.
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Affiliation(s)
- Jelle Zandveld
- Plant Sciences Group, Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Joost van den Heuvel
- Plant Sciences Group, Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.,Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, NE4 5PL, United Kingdom
| | - Maarten Mulder
- Evolutionary Biology Group, Institute Biology Leiden, Leiden University, Rapenburg 58, 2311 EZ, Leiden, The Netherlands
| | - Paul M Brakefield
- Department of Zoology, University Museum of Zoology Cambridge, University of Cambridge, CB2 3EJ Cambridge, United Kingdom
| | - Thomas B L Kirkwood
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, NE4 5PL, United Kingdom.,Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Daryl P Shanley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, NE4 5PL, United Kingdom
| | - Bas J Zwaan
- Plant Sciences Group, Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
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17
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Mitochondrial form, function and signalling in aging. Biochem J 2017; 473:3421-3449. [PMID: 27729586 DOI: 10.1042/bcj20160451] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 06/17/2016] [Indexed: 02/07/2023]
Abstract
Aging is often accompanied by a decline in mitochondrial mass and function in different tissues. Additionally, cell resistance to stress is frequently found to be prevented by higher mitochondrial respiratory capacity. These correlations strongly suggest mitochondria are key players in aging and senescence, acting by regulating energy homeostasis, redox balance and signalling pathways central in these processes. However, mitochondria display a wide array of functions and signalling properties, and the roles of these different characteristics are still widely unexplored. Furthermore, differences in mitochondrial properties and responses between tissues and cell types, and how these affect whole body metabolism are also still poorly understood. This review uncovers aspects of mitochondrial biology that have an impact upon aging in model organisms and selected mammalian cells and tissues.
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18
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The Nuts and Bolts of Transcriptionally Silent Chromatin in Saccharomyces cerevisiae. Genetics 2017; 203:1563-99. [PMID: 27516616 DOI: 10.1534/genetics.112.145243] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/30/2016] [Indexed: 12/31/2022] Open
Abstract
Transcriptional silencing in Saccharomyces cerevisiae occurs at several genomic sites including the silent mating-type loci, telomeres, and the ribosomal DNA (rDNA) tandem array. Epigenetic silencing at each of these domains is characterized by the absence of nearly all histone modifications, including most prominently the lack of histone H4 lysine 16 acetylation. In all cases, silencing requires Sir2, a highly-conserved NAD(+)-dependent histone deacetylase. At locations other than the rDNA, silencing also requires additional Sir proteins, Sir1, Sir3, and Sir4 that together form a repressive heterochromatin-like structure termed silent chromatin. The mechanisms of silent chromatin establishment, maintenance, and inheritance have been investigated extensively over the last 25 years, and these studies have revealed numerous paradigms for transcriptional repression, chromatin organization, and epigenetic gene regulation. Studies of Sir2-dependent silencing at the rDNA have also contributed to understanding the mechanisms for maintaining the stability of repetitive DNA and regulating replicative cell aging. The goal of this comprehensive review is to distill a wide array of biochemical, molecular genetic, cell biological, and genomics studies down to the "nuts and bolts" of silent chromatin and the processes that yield transcriptional silencing.
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19
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Kainz K, Tadic J, Zimmermann A, Pendl T, Carmona-Gutierrez D, Ruckenstuhl C, Eisenberg T, Madeo F. Methods to Assess Autophagy and Chronological Aging in Yeast. Methods Enzymol 2016; 588:367-394. [PMID: 28237110 DOI: 10.1016/bs.mie.2016.09.086] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Autophagy is a catabolic process that is crucial for cellular homeostasis and adaptive response to changing environments. Importantly, autophagy has been shown to be induced in many longevity-associated scenarios and to be required to maintain lifespan extension. Notably, autophagy is a highly conserved cellular process among eukaryotes, and the yeast Saccharomyces cerevisiae has become a universal model system for unraveling the molecular machinery underlying autophagic mechanisms. Here, we discuss different protocols to monitor survival and autophagy of yeast cells upon chronological aging. These include the use of propidium iodide to assess the loss of cell membrane integrity, as well as clonogenic assays to directly determine survival rates. Additionally, we describe methods to quantify autophagic flux, including the alkaline phosphatase activity or the GFP liberation assays, which measure the delivery of autophagosomal cargo to the vacuole. In sum, we have recapped established protocols used to evaluate a link between lifespan extension and autophagy in yeast.
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Affiliation(s)
- K Kainz
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - J Tadic
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - A Zimmermann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - T Pendl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - D Carmona-Gutierrez
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - C Ruckenstuhl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - T Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - F Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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20
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Zadrag-Tecza R, Skoneczna A. Reproductive potential and instability of the rDNA region of the Saccharomyces cerevisiae yeast: Common or separate mechanisms of regulation? Exp Gerontol 2016; 84:29-39. [DOI: 10.1016/j.exger.2016.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/17/2016] [Indexed: 12/15/2022]
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21
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Exploring the power of yeast to model aging and age-related neurodegenerative disorders. Biogerontology 2016; 18:3-34. [PMID: 27804052 DOI: 10.1007/s10522-016-9666-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/24/2016] [Indexed: 12/12/2022]
Abstract
Aging is a multifactorial process determined by molecular, cellular and systemic factors and it is well established that advancing age is a leading risk factor for several neurodegenerative diseases. In fact, the close association of aging and neurodegenerative disorders has placed aging as the greatest social and economic challenge of the 21st century, and age-related diseases have also become a key priority for countries worldwide. The growing need to better understand both aging and neurodegenerative processes has led to the development of simple eukaryotic models amenable for mechanistic studies. Saccharomyces cerevisiae has proven to be an unprecedented experimental model to study the fundamental aspects of aging and to decipher the intricacies of neurodegenerative disorders greatly because the molecular mechanisms underlying these processes are evolutionarily conserved from yeast to human. Moreover, yeast offers several methodological advantages allowing a rapid and relatively easy way of establishing gene-protein-function associations. Here we review different aging theories, common cellular pathways driving aging and neurodegenerative diseases and discuss the major contributions of yeast to the state-of-art knowledge in both research fields.
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22
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Molon M, Szajwaj M, Tchorzewski M, Skoczowski A, Niewiadomska E, Zadrag-Tecza R. The rate of metabolism as a factor determining longevity of the Saccharomyces cerevisiae yeast. AGE (DORDRECHT, NETHERLANDS) 2016; 38:11. [PMID: 26783001 PMCID: PMC5005888 DOI: 10.1007/s11357-015-9868-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/22/2015] [Indexed: 05/13/2023]
Abstract
Despite many controversies, the yeast Saccharomyces cerevisiae continues to be used as a model organism for the study of aging. Numerous theories and hypotheses have been created for several decades, yet basic mechanisms of aging have remained unclear. Therefore, the principal aim of this work is to propose a possible mechanism leading to increased longevity in yeast. In this paper, we suggest for the first time that there is a link between decreased metabolic activity, fertility and longevity expressed as time of life in yeast. Determination of reproductive potential and total lifespan with the use of fob1Δ and sfp1Δ mutants allows us to compare the "longevity" presented as the number of produced daughters with the longevity expressed as the time of life. The results of analyses presented in this paper suggest the need for a change in the definition of longevity of yeast by taking into consideration the time parameter. The mutants that have been described as "long-lived" in the literature, such as the fob1Δ mutant, have an increased reproductive potential but live no longer than their standard counterparts. On the other hand, the sfp1Δ mutant and the wild-type strain produce a similar number of daughter cells, but the former lives much longer. Our results demonstrate a correlation between the decreased efficiency of the translational apparatus and the longevity of the sfp1Δ mutant. We suggest that a possible factor regulating the lifespan is the rate of cell metabolism. To measure the basic metabolism of the yeast cells, we used the isothermal microcalorimetry method. In the case of sfp1Δ, the flow of energy, ATP concentration, polysome profile and translational fitness are significantly lower in comparison with the wild-type strain and the fob1Δ mutant.
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Affiliation(s)
- Mateusz Molon
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, Rzeszow, 35-601, Poland.
| | - Monika Szajwaj
- Department of Molecular Biology, Maria Curie-Sklodowska University, Lublin, Poland
| | - Marek Tchorzewski
- Department of Molecular Biology, Maria Curie-Sklodowska University, Lublin, Poland
| | | | - Ewa Niewiadomska
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Krakow, Poland
| | - Renata Zadrag-Tecza
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, Rzeszow, 35-601, Poland
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23
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Sirtuins Link Inflammation and Metabolism. J Immunol Res 2016; 2016:8167273. [PMID: 26904696 PMCID: PMC4745579 DOI: 10.1155/2016/8167273] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 12/30/2015] [Indexed: 12/12/2022] Open
Abstract
Sirtuins (SIRT), first discovered in yeast as NAD+ dependent epigenetic and metabolic regulators, have comparable activities in human physiology and disease. Mounting evidence supports that the seven-member mammalian sirtuin family (SIRT1–7) guard homeostasis by sensing bioenergy needs and responding by making alterations in the cell nutrients. Sirtuins play a critical role in restoring homeostasis during stress responses. Inflammation is designed to “defend and mend” against the invading organisms. Emerging evidence supports that metabolism and bioenergy reprogramming direct the sequential course of inflammation; failure of homeostasis retrieval results in many chronic and acute inflammatory diseases. Anabolic glycolysis quickly induced (compared to oxidative phosphorylation) for ROS and ATP generation is needed for immune activation to “defend” against invading microorganisms. Lipolysis/fatty acid oxidation, essential for cellular protection/hibernation and cell survival in order to “mend,” leads to immune repression. Acute/chronic inflammations are linked to altered glycolysis and fatty acid oxidation, at least in part, by NAD+ dependent function of sirtuins. Therapeutically targeting sirtuins may provide a new class of inflammation and immune regulators. This review discusses how sirtuins integrate metabolism, bioenergetics, and immunity during inflammation and how sirtuin-directed treatment improves outcome in chronic inflammatory diseases and in the extreme stress response of sepsis.
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24
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Liu P, Young TZ, Acar M. Yeast Replicator: A High-Throughput Multiplexed Microfluidics Platform for Automated Measurements of Single-Cell Aging. Cell Rep 2015; 13:634-644. [PMID: 26456818 DOI: 10.1016/j.celrep.2015.09.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/12/2015] [Accepted: 09/03/2015] [Indexed: 12/23/2022] Open
Abstract
The yeast Saccharomyces cerevisiae is a model organism for replicative aging studies; however, conventional lifespan measurement platforms have several limitations. Here, we present a microfluidics platform that facilitates simultaneous lifespan and gene expression measurements of aging yeast cells. Our multiplexed high-throughput platform offers the capability to perform independent lifespan experiments using different yeast strains or growth media. Using this platform in minimal media environments containing glucose, we measured the full lifespan of individual yeast cells in wild-type and canonical gene deletion backgrounds. Compared to glucose, in galactose we observed a 16.8% decrease in replicative lifespan accompanied by an ∼2-fold increase in single-cell oxidative stress levels reported by PSOD1-mCherry. Using PGAL1-YFP to measure the activity of the bistable galactose network, we saw that OFF and ON cells are similar in their lifespan. Our work shows that aging cells are committed to a single phenotypic state throughout their lifespan.
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Affiliation(s)
- Ping Liu
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 840 West Campus Drive, West Haven, CT 06516, USA
| | - Thomas Z Young
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 840 West Campus Drive, West Haven, CT 06516, USA
| | - Murat Acar
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 840 West Campus Drive, West Haven, CT 06516, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA.
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25
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Molon M, Zadrag-Tecza R, Bilinski T. The longevity in the yeast Saccharomyces cerevisiae: A comparison of two approaches for assessment the lifespan. Biochem Biophys Res Commun 2015; 460:651-6. [PMID: 25817783 DOI: 10.1016/j.bbrc.2015.03.085] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 03/16/2015] [Indexed: 11/25/2022]
Abstract
Longevity of the selected "longevity mutants" of yeast was studied using two methods. The standard method was based on counting the number of daughter cells produced. Modification of that method allowed for establishing the length of life expressed in units of time. It appeared that all the studied "deletion longevity mutants" showed a statistically meaningful increase in the number of daughters produced (replicative lifespan), whereas only one of the mutants, previously regarded as "short lived", showed a meaningful increase in the time of life. The analysis of the available data shows that the time of life of most yeast strains is similar irrespective of their genetic background and mutations, which suggests a quasi-programmed nature of yeast death.
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Affiliation(s)
- Mateusz Molon
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, 35-601 Rzeszow, Poland.
| | - Renata Zadrag-Tecza
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, 35-601 Rzeszow, Poland
| | - Tomasz Bilinski
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, 35-601 Rzeszow, Poland
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26
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Pires EJ, Teixeira JA, Brányik T, Côrte-Real M, Brandão T, Vicente AA. High gravity primary continuous beer fermentation using flocculent yeast biomass. JOURNAL OF THE INSTITUTE OF BREWING 2014. [DOI: 10.1002/jib.171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Eduardo J. Pires
- Institute for Biotechnology and Bioengineering, Centre for Biological Engineering; Universidade do Minho; Campus de Gualtar 4710-057 Braga Portugal
| | - José A. Teixeira
- Institute for Biotechnology and Bioengineering, Centre for Biological Engineering; Universidade do Minho; Campus de Gualtar 4710-057 Braga Portugal
| | - Tomás Brányik
- Department of Biotechnology; Institute of Chemical Technology Prague; Technická 5 166 28 Prague 6 Czech Republic
| | - Manuela Côrte-Real
- Centre of Molecular and Environmental Biology; Department of Biology, University of Minho
| | - Tiago Brandão
- UNICER − Bebidas de Portugal SGPS, SA; Leça do Balio 4466-955 S Mamede de Infesta Portugal
| | - António A. Vicente
- Institute for Biotechnology and Bioengineering, Centre for Biological Engineering; Universidade do Minho; Campus de Gualtar 4710-057 Braga Portugal
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27
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Denoth Lippuner A, Julou T, Barral Y. Budding yeast as a model organism to study the effects of age. FEMS Microbiol Rev 2014; 38:300-25. [PMID: 24484434 DOI: 10.1111/1574-6976.12060] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 12/13/2013] [Accepted: 01/06/2014] [Indexed: 12/20/2022] Open
Abstract
Although a budding yeast culture can be propagated eternally, individual yeast cells age and eventually die. The detailed knowledge of this unicellular eukaryotic species as well as the powerful tools developed to study its physiology makes budding yeast an ideal model organism to study the mechanisms involved in aging. Considering both detrimental and positive aspects of age, we review changes occurring during aging both at the whole-cell level and at the intracellular level. The possible mechanisms allowing old cells to produce rejuvenated progeny are described in terms of accumulation and inheritance of aging factors. Based on the dynamic changes associated with age, we distinguish different stages of age: early age, during which changes do not impair cell growth; intermediate age, during which aging factors start to accumulate; and late age, which corresponds to the last divisions before death. For each aging factor, we examine its asymmetric segregation and whether it plays a causal role in aging. Using the example of caloric restriction, we describe how the aging process can be modulated at different levels and how changes in different organelles might interplay with each other. Finally, we discuss the beneficial aspects that might be associated with age.
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28
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Pires EJ, Teixeira JA, Brányik T, Côrte-Real M, Vicente AA. Maintaining yeast viability in continuous primary beer fermentation. JOURNAL OF THE INSTITUTE OF BREWING 2014. [DOI: 10.1002/jib.111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Eduardo J. Pires
- IBB - Institute for Biotechnology and Bioengineering; Centre for Biological Engineering; Universidade do Minho; Campus de Gualtar 4710-057 Braga Portugal
| | - José A. Teixeira
- IBB - Institute for Biotechnology and Bioengineering; Centre for Biological Engineering; Universidade do Minho; Campus de Gualtar 4710-057 Braga Portugal
| | - Tomás Brányik
- Department of Biotechnology; Institute of Chemical Technology Prague; Technická 5 166 28 Prague 6 Czech Republic
| | - Manuela Côrte-Real
- Centre of Molecular and Environmental Biology; Department of Biology; University of Minho; Campus de Gualtar 4710-057 Braga Portugal
| | - António A. Vicente
- IBB - Institute for Biotechnology and Bioengineering; Centre for Biological Engineering; Universidade do Minho; Campus de Gualtar 4710-057 Braga Portugal
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29
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Isp7 is a novel regulator of amino acid uptake in the TOR signaling pathway. Mol Cell Biol 2013; 34:794-806. [PMID: 24344203 DOI: 10.1128/mcb.01473-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
TOR proteins reside in two distinct complexes, TOR complexes 1 and 2 (TORC1 and TORC2), that are central for the regulation of cellular growth, proliferation, and survival. TOR is also the target for the immunosuppressive and anticancer drug rapamycin. In Schizosaccharomyces pombe, disruption of the TSC complex, mutations in which can lead to the tuberous sclerosis syndrome in humans, results in a rapamycin-sensitive phenotype under poor nitrogen conditions. We show here that the sensitivity to rapamycin is mediated via inhibition of TORC1 and suppressed by overexpression of isp7(+), a member of the family of 2-oxoglutarate-Fe(II)-dependent oxygenase genes. The transcript level of isp7(+) is negatively regulated by TORC1 but positively regulated by TORC2. Yet we find extensive similarity between the transcriptome of cells disrupted for isp7(+) and cells mutated in the catalytic subunit of TORC1. Moreover, Isp7 regulates amino acid permease expression in a fashion similar to that of TORC1 and opposite that of TORC2. Overexpression of isp7(+) induces TORC1-dependent phosphorylation of ribosomal protein Rps6 while inhibiting TORC2-dependent phosphorylation and activation of the AGC-like kinase Gad8. Taken together, our findings suggest a central role for Isp7 in amino acid homeostasis and the presence of isp7(+)-dependent regulatory loops that affect both TORC1 and TORC2.
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30
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Swinnen E, Ghillebert R, Wilms T, Winderickx J. Molecular mechanisms linking the evolutionary conserved TORC1-Sch9 nutrient signalling branch to lifespan regulation in Saccharomyces cerevisiae. FEMS Yeast Res 2013; 14:17-32. [PMID: 24102693 DOI: 10.1111/1567-1364.12097] [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: 05/23/2013] [Revised: 07/09/2013] [Accepted: 09/06/2013] [Indexed: 01/13/2023] Open
Abstract
The knowledge on the molecular aspects regulating ageing in eukaryotic organisms has benefitted greatly from studies using the budding yeast Saccharomyces cerevisiae. Indeed, many aspects involved in the control of lifespan appear to be well conserved among species. Of these, the lifespan-extending effects of calorie restriction (CR) and downregulation of nutrient signalling through the target of rapamycin (TOR) pathway are prime examples. Here, we present an overview on the molecular mechanisms by which these interventions mediate lifespan extension in yeast. Several models have been proposed in the literature, which should be seen as complementary, instead of contradictory. Results indicate that CR mediates a large amount of its effect by downregulating signalling through the TORC1-Sch9 branch. In addition, we note that Sch9 is more than solely a downstream effector of TORC1, and documented connections with sphingolipid metabolism may be particularly interesting for future research on ageing mechanisms. As Sch9 comprises the yeast orthologue of the mammalian PKB/Akt and S6K1 kinases, future studies in yeast may continue to serve as an attractive model to elucidate conserved mechanisms involved in ageing and age-related diseases in humans.
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31
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Clay L, Barral Y. New approaches to an age-old problem. Curr Opin Biotechnol 2013; 24:784-9. [PMID: 23726155 DOI: 10.1016/j.copbio.2013.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/23/2013] [Accepted: 04/28/2013] [Indexed: 02/07/2023]
Abstract
Progress in the last decades indicated that ageing might be a universal fact of life. However, the molecular mechanisms underlying this process remain a major challenge in biology. Our relatively long life span and huge variations in lifestyle make detailed studies of ageing in humans difficult to interpret. In contrast, the relatively simple yeast Saccharomyces cerevisiae (budding yeast) has been a critical model in the field of ageing research for decades. Systems biology has contributed to the ageing field by mapping complex regulatory networks and resolving the dynamics of signal transduction pathways. In this review we first review the current understanding of ageing in yeast, then highlight the recent high-throughput systems and system biology approaches that could be used to further our understanding of ageing in yeast.
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Affiliation(s)
- Lori Clay
- Institute of Biochemistry, Department of Biology, ETH Zurich, Schafmattstrasse 18, 8093 Zurich, Switzerland
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32
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The eye as a model of ageing in translational research--molecular, epigenetic and clinical aspects. Ageing Res Rev 2013; 12:490-508. [PMID: 23274270 DOI: 10.1016/j.arr.2012.11.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 11/16/2012] [Accepted: 11/19/2012] [Indexed: 12/13/2022]
Abstract
The eye and visual system are valuable in many areas of translational research such as stem cell therapy, transplantation research and gene therapy. Changes in many ocular tissues can be measured directly, easily and objectively in vivo (e.g. lens transparency; retinal blood vessel calibre; corneal endothelial cell counts) and so the eye may also be a uniquely useful site as a model of ageing. This review details cellular, molecular and epigenetic mechanisms related to ageing within the eye, and describes ocular parameters that can be directly measured clinically and which might be of value in ageing research as the translational "window to the rest of the body". The eye is likely to provide a valuable model for validating biomarkers of ageing at molecular, epigenetic, cellular and clinical levels. A research agenda to definitively establish the relationship between biomarkers of ageing and ocular parameters is proposed.
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33
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Wright J, Dungrawala H, Bright RK, Schneider BL. A growing role for hypertrophy in senescence. FEMS Yeast Res 2012; 13:2-6. [PMID: 23107076 DOI: 10.1111/1567-1364.12015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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34
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Volejníková A, Hlousková J, Sigler K, Pichová A. Vital mitochondrial functions show profound changes during yeast culture ageing. FEMS Yeast Res 2012; 13:7-15. [PMID: 22938652 DOI: 10.1111/1567-1364.12001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 08/22/2012] [Accepted: 08/27/2012] [Indexed: 12/25/2022] Open
Abstract
During a 10-day culture ageing, cells of the wild-type Saccharomyces cerevisiae strain JC 482 retain their viability, while mitochondrial function and morphology change. Cell routine and uncoupled respiration rates increase to a maximum on day 4 and then decline to near zero. The decline, which occurs also in mitochondria isolated from cells of different age, is not due to increasing proportion of petites. Rhodamine 123 fluorescence intensity reporting on mitochondrial membrane potential appears to drop slightly for 4 days and then more sharply at the time when respiration rate also decreases. The MitoTracker Green fluorescent signal related to the mitochondrial content per cell also decreases. The branched tubular mitochondrial network of 1-day-old cells dissolves into short fragments; during the first 4 days, this fragmentation is associated with increasing function of mitochondria, while later on, it accompanies functional decline, which is also indicated by the decreasing ratio of Rhodamine 123 fluorescence to MitoTracker Green fluorescence. As shown by cell counting, microscopy and flow cytometry, the cell size distribution in the population broadens, and the population thus becomes more heterogeneous. The changes in respiration rate, mitochondrial membrane potential, mass and structure point to changes in the mitochondrial status during ageing.
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Affiliation(s)
- Andrea Volejníková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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35
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Cohen A, Ross L, Nachman I, Bar-Nun S. Aggregation of polyQ proteins is increased upon yeast aging and affected by Sir2 and Hsf1: novel quantitative biochemical and microscopic assays. PLoS One 2012; 7:e44785. [PMID: 22970306 PMCID: PMC3435303 DOI: 10.1371/journal.pone.0044785] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 08/13/2012] [Indexed: 11/18/2022] Open
Abstract
Aging-related neurodegenerative disorders, such as Parkinson's, Alzheimer's and Huntington's diseases, are characterized by accumulation of protein aggregates in distinct neuronal cells that eventually die. In Huntington's disease, the protein huntingtin forms aggregates, and the age of disease onset is inversely correlated to the length of the protein's poly-glutamine tract. Using quantitative assays to estimate microscopically and capture biochemically protein aggregates, here we study in Saccharomyces cerevisiae aging-related aggregation of GFP-tagged, huntingtin-derived proteins with different polyQ lengths. We find that the short 25Q protein never aggregates whereas the long 103Q version always aggregates. However, the mid-size 47Q protein is soluble in young logarithmically growing yeast but aggregates as the yeast cells enter the stationary phase and age, allowing us to plot an “aggregation timeline”. This aging-dependent aggregation was associated with increased cytotoxicity. We also show that two aging-related genes, SIR2 and HSF1, affect aggregation of the polyQ proteins. In Δsir2 strain the aging-dependent aggregation of the 47Q protein is aggravated, while overexpression of the transcription factor Hsf1 attenuates aggregation. Thus, the mid-size 47Q protein and our quantitative aggregation assays provide valuable tools to unravel the roles of genes and environmental conditions that affect aging-related aggregation.
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Affiliation(s)
- Aviv Cohen
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Liron Ross
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Iftach Nachman
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Shoshana Bar-Nun
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
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36
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Farrugia G, Balzan R. Oxidative stress and programmed cell death in yeast. Front Oncol 2012; 2:64. [PMID: 22737670 PMCID: PMC3380282 DOI: 10.3389/fonc.2012.00064] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 06/02/2012] [Indexed: 12/11/2022] Open
Abstract
Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed.
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Affiliation(s)
- Gianluca Farrugia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta
| | - Rena Balzan
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta
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37
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Miceli MV, Jiang JC, Tiwari A, Rodriguez-Quiñones JF, Jazwinski SM. Loss of mitochondrial membrane potential triggers the retrograde response extending yeast replicative lifespan. Front Genet 2012; 2:102. [PMID: 22303396 PMCID: PMC3266616 DOI: 10.3389/fgene.2011.00102] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 12/17/2011] [Indexed: 11/20/2022] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, loss of mitochondrial DNA (rho0) can induce the retrograde response under appropriate conditions, resulting in increased replicative lifespan (RLS). Although the retrograde pathway has been extensively elaborated, the nature of the mitochondrial signal triggering this response has not been clear. Mitochondrial membrane potential (MMP) was severely reduced in rho0 compared to rho+ cells, and RLS was concomitantly extended. To examine the role of MMP in the retrograde response, MMP was increased in the rho0 strain by introducing a mutation in the ATP1 gene, and it was decreased in rho+ cells by deletion of COX4. The ATP1-111 mutation in rho0 cells partially restored the MMP and reduced mean RLS to that of rho+ cells. COX4 deletion decreased MMP in rho+ cells to a value intermediate between rho+ and rho0 cells and similarly increased RLS. The increase in expression of CIT2, the diagnostic gene for the retrograde response, seen in rho0 cells, was substantially suppressed in the presence of the ATP1-111 mutation. In contrast, CIT2 expression increased in rho+ cells on deletion of COX4. Activation of the retrograde response results in the translocation of the transcription factor Rtg3 from the cytoplasm to the nucleus. Rtg3–GFP translocation to the nucleus was directly observed in rho0 and rho+cox4Δ cells, but it was blunted in rho0 cells with the ATP1-111 mutation. We conclude that a decrease in MMP is the signal that initiates the retrograde response and leads to increased RLS.
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Affiliation(s)
- Michael V Miceli
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center New Orleans, LA, USA
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38
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Wei M, Madia F, Longo VD. Studying age-dependent genomic instability using the S. cerevisiae chronological lifespan model. J Vis Exp 2011:3030. [PMID: 21989366 PMCID: PMC3230202 DOI: 10.3791/3030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Studies using the Saccharomyces cerevisiae aging model have uncovered life span regulatory pathways that are partially conserved in higher eukaryotes1-2. The simplicity and power of the yeast aging model can also be explored to study DNA damage and genome maintenance as well as their contributions to diseases during aging. Here, we describe a system to study age-dependent DNA mutations, including base substitutions, frame-shift mutations, gross chromosomal rearrangements, and homologous/homeologous recombination, as well as nuclear DNA repair activity by combining the yeast chronological life span with simple DNA damage and mutation assays. The methods described here should facilitate the identification of genes/pathways that regulate genomic instability and the mechanisms that underlie age-dependent DNA mutations and cancer in mammals.
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Affiliation(s)
- Min Wei
- Andrus Gerontology Center, Department of Biological Sciences, University of Southern California, Los Angeles, USA
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39
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Botta G, Turn CS, Quintyne NJ, Kirchman PA. Increased iron supplied through Fet3p results in replicative life span extension of Saccharomyces cerevisiae under conditions requiring respiratory metabolism. Exp Gerontol 2011; 46:827-32. [PMID: 21798334 DOI: 10.1016/j.exger.2011.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 07/07/2011] [Accepted: 07/11/2011] [Indexed: 01/05/2023]
Abstract
We have previously shown that copper supplementation extends the replicative life span of Saccharomyces cerevisiae when grown under conditions forcing cells to respire. We now show that copper's effect on life span is through Fet3p, a copper containing enzyme responsible for high affinity transport of iron into yeast cells. Life span extensions can also be obtained by supplementing the growth medium with 1mM ferric chloride. Extension by high iron levels is still dependent on the presence of Fet3p. Life span extension by iron or copper requires growth on media containing glycerol as the sole carbon source, which forces yeast to respire. Yeast grown on glucose containing media supplemented with iron show no extension of life span. The iron associated with cells grown in media supplemented with copper or iron is 1.4-1.8 times that of cells grown without copper or iron supplementation. As with copper supplementation, iron supplementation partially rescues the life span of superoxide dismutase mutants. Cells grown with copper supplementation display decreased production of superoxide as measured by dihydroethidium staining.
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Affiliation(s)
- Gabriela Botta
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, United States.
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40
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Respiratory and TCA cycle activities affect S. cerevisiae lifespan, response to caloric restriction and mtDNA stability. J Bioenerg Biomembr 2011; 43:483-91. [PMID: 21833600 DOI: 10.1007/s10863-011-9377-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 06/27/2011] [Indexed: 10/18/2022]
Abstract
We studied the importance of respiratory fitness in S. cerevisiae lifespan, response to caloric restriction (CR) and mtDNA stability. Mutants harboring mtDNA instability and electron transport defects do not respond to CR, while tricarboxylic acid cycle mutants presented extended lifespans due to CR. Interestingly, mtDNA is unstable in cells lacking dihydrolipoyl dehydrogenase under CR conditions, and cells lacking aconitase under standard conditions (both enzymes are components of the TCA and mitochondrial nucleoid). Altogether, our data indicate that respiratory integrity is required for lifespan extension by CR and that mtDNA stability is regulated by nucleoid proteins in a glucose-sensitive manner.
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41
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McGuinness D, McGuinness DH, McCaul JA, Shiels PG. Sirtuins, bioageing, and cancer. J Aging Res 2011; 2011:235754. [PMID: 21766030 PMCID: PMC3134127 DOI: 10.4061/2011/235754] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Accepted: 03/16/2011] [Indexed: 01/20/2023] Open
Abstract
The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function, indicative of their key biochemical roles. Sirtuins are heavily implicated in cell cycle, cell division, transcription regulation, and metabolism, which places the various family members at critical junctures in cellular metabolism. Typically, Sirtuins have been implicated in the preservation of genomic stability and in the prolongation of lifespan though many of their target interactions remain unknown.
Sirtuins play key roles in tumourigenesis, as some have tumour-suppressor functions and others influence tumours through their control of the metabolic state of the cell. Their links to ageing have also highlighted involvement in various age-related and degenerative diseases. Here, we discuss the current understanding of the role of Sirtuins in age-related diseases while taking a closer look at their roles and functions in maintaining genomic stability and their influence on telomerase and telomere function.
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Affiliation(s)
- D McGuinness
- College of Medical, Veterinary and Life Sciences, Institute of Cancer Sciences, University of Glasgow, Glasgow G11 6NT, Scotland, UK
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42
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Rotili D, Carafa V, Tarantino D, Botta G, Nebbioso A, Altucci L, Mai A. Simplification of the tetracyclic SIRT1-selective inhibitor MC2141: Coumarin- and pyrimidine-based SIRT1/2 inhibitors with different selectivity profile. Bioorg Med Chem 2011; 19:3659-68. [DOI: 10.1016/j.bmc.2011.01.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 12/22/2010] [Accepted: 01/13/2011] [Indexed: 11/16/2022]
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43
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Lam YT, Aung-Htut MT, Lim YL, Yang H, Dawes IW. Changes in reactive oxygen species begin early during replicative aging of Saccharomyces cerevisiae cells. Free Radic Biol Med 2011; 50:963-70. [PMID: 21255640 DOI: 10.1016/j.freeradbiomed.2011.01.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 12/22/2010] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
Increased reactive oxygen species (ROS) are a feature of aging cells, but little is known about when ROS generation begins as cells age. Here we show how ROS change in Saccharomyces cerevisiae cells throughout their early replicative life span using the fluorescent ROS indicator dihydroethidium (DHE), which has some specificity for the superoxide anion. Cells in a particular age range were heterogeneous with respect to their ROS burden. Surprisingly, some cells as young as 5-7 generations acquired a greatly increased level of ROS detected by DHE relative to virgin cells. By 12 generations 50% of cells had a substantial ROS burden despite being only halfway through their life span. In contrast to the wild type, cells of a sir2 mutant had lower levels of ROS reacting with DHE. Daughters from older mothers had low ROS levels, and this asymmetric distribution of ROS was SIR2-independent. Mitochondrial fragmentation also began to occur in cells after 4 generations and increased markedly as cells aged. Daughter cells regenerated normal tubular mitochondria despite the fragmentation of mitochondria in the mother cells, whereas daughters of the sir2 mutant had fragmented mitochondria at all ages.
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Affiliation(s)
- Yuen T Lam
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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44
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Lele UN, Baig UI, Watve MG. Phenotypic plasticity and effects of selection on cell division symmetry in Escherichia coli. PLoS One 2011; 6:e14516. [PMID: 21249222 PMCID: PMC3018420 DOI: 10.1371/journal.pone.0014516] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 12/14/2010] [Indexed: 11/19/2022] Open
Abstract
Aging has been demonstrated in unicellular organisms and is presumably due to asymmetric distribution of damaged proteins and other components during cell division. Whether the asymmetry-induced aging is inevitable or an adaptive and adaptable response is debated. Although asymmetric division leads to aging and death of some cells, it increases the effective growth rate of the population as shown by theoretical and empirical studies. Mathematical models predict on the other hand, that if the cells divide symmetrically, cellular aging may be delayed or absent, growth rate will be reduced but growth yield will increase at optimum repair rates. Therefore in nutritionally dilute (oligotrophic) environments, where growth yield may be more critical for survival, symmetric division may get selected. These predictions have not been empirically tested so far. We report here that Escherichia coli grown in oligotrophic environments had greater morphological and functional symmetry in cell division. Both phenotypic plasticity and genetic selection appeared to shape cell division time asymmetry but plasticity was lost on prolonged selection. Lineages selected on high nutrient concentration showed greater frequency of presumably old or dead cells. Further, there was a negative correlation between cell division time asymmetry and growth yield but there was no significant correlation between asymmetry and growth rate. The results suggest that cellular aging driven by asymmetric division may not be hardwired but shows substantial plasticity as well as evolvability in response to the nutritional environment.
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Affiliation(s)
- Uttara N. Lele
- Department of Microbiology, Abasaheb Garware College, Pune, India
| | - Ulfat I. Baig
- Department of Microbiology, Abasaheb Garware College, Pune, India
| | - Milind G. Watve
- Indian Institute of Science, Education, and Research, Pune, India
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45
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Abstract
In the past several decades the budding yeast Saccharomyces cerevisiae has emerged as a prominent model for aging research. The creation of a single-gene deletion collection covering the majority of open reading frames in the yeast genome and advances in genomic technologies have opened yeast research to genome-scale screens for a variety of phenotypes. A number of screens have been performed looking for genes that modify secondary age-associated phenotypes such as stress resistance or growth rate. More recently, moderate-throughput methods for measuring replicative life span and high-throughput methods for measuring chronological life span have allowed for the first unbiased screens aimed at directly identifying genes involved in determining yeast longevity. In this chapter we discuss large-scale life span studies performed in yeast and their implications for research related to the basic biology of aging.
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Affiliation(s)
- George L Sutphin
- Department of Pathology and the Molecular and Cellular Biology Program, University of Washington, Seattle, WA, 98195-7470, USA,
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46
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Aris JP, Fishwick LK, Marraffini ML, Seo AY, Leeuwenburgh C, Dunn WA. Amino acid homeostasis and chronological longevity in Saccharomyces cerevisiae. Subcell Biochem 2011; 57:161-86. [PMID: 22094422 DOI: 10.1007/978-94-007-2561-4_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Understanding how non-dividing cells remain viable over long periods of time, which may be decades in humans, is of central importance in understanding mechanisms of aging and longevity. The long-term viability of non-dividing cells, known as chronological longevity, relies on cellular processes that degrade old components and replace them with new ones. Key among these processes is amino acid homeostasis. Amino acid homeostasis requires three principal functions: amino acid uptake, de novo synthesis, and recycling. Autophagy plays a key role in recycling amino acids and other metabolic building blocks, while at the same time removing damaged cellular components such as mitochondria and other organelles. Regulation of amino acid homeostasis and autophagy is accomplished by a complex web of pathways that interact because of the functional overlap at the level of recycling. It is becoming increasingly clear that amino acid homeostasis and autophagy play important roles in chronological longevity in yeast and higher organisms. Our goal in this chapter is to focus on mechanisms and pathways that link amino acid homeostasis, autophagy, and chronological longevity in yeast, and explore their relevance to aging and longevity in higher eukaryotes.
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Affiliation(s)
- John P Aris
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL, 32610-0235, USA,
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47
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Sirtuin regulation in calorie restriction. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:1576-83. [DOI: 10.1016/j.bbapap.2009.09.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/10/2009] [Accepted: 09/15/2009] [Indexed: 12/28/2022]
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48
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Barros MH, da Cunha FM, Oliveira GA, Tahara EB, Kowaltowski AJ. Yeast as a model to study mitochondrial mechanisms in ageing. Mech Ageing Dev 2010; 131:494-502. [DOI: 10.1016/j.mad.2010.04.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 04/19/2010] [Accepted: 04/27/2010] [Indexed: 01/08/2023]
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49
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Postma L, Lehrach H, Ralser M. Surviving in the cold: yeast mutants with extended hibernating lifespan are oxidant sensitive. Aging (Albany NY) 2009; 1:957-60. [PMID: 20157578 PMCID: PMC2815748 DOI: 10.18632/aging.100104] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 11/10/2009] [Indexed: 12/03/2022]
Abstract
Metabolic
activity generates oxidizing molecules throughout life, but it is still
debated if the resulting damage of macromolecules is a causality, or
consequence, of the aging process. This problem demands for studying
growth- and longevity phenotypes separately. Here, we assayed a complete
collection of haploid Saccharomyces cerevisiae knock-out strains for
their capacity to endure long periods at low metabolic rates. Deletion of
93 genes, predominantly factors of primary metabolism, allowed yeast to
survive for more than 58 months in the cold. The majority of these deletion
strains were not resistant against oxidants or reductants, but many were
hypersensitive. Hence, survival at low metabolic rates has limiting genetic
components, and correlates with stress resistance inversely. Indeed,
maintaining the energy consuming anti-oxidative machinery seems to be
disadvantageous under coldroom conditions.
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Affiliation(s)
- Lucie Postma
- Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
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50
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Abstract
Calorie restriction (CR) extends lifespan in yeast, worms, flies and mammals, suggesting that it acts via a conserved mechanism. In yeast, activation of the NAD-dependent histone deacetylase, Sir2, by CR is thought to increase silencing at the ribosomal DNA, thereby reducing the recombination-induced generation of extrachromosomal rDNA circles, hence increasing replicative lifespan. Although accumulation of extrachromosomal rDNA circles is specific to yeast aging, it is thought that Sirtuin activation represents a conserved longevity mechanism through which the beneficial effects of CR are mediated in various species. We show here that growing yeast on 0.05 or 0.5% glucose (severe and moderate CR, respectively) does not increase silencing at either sub-telomeric or rDNA loci compared with standard (2% glucose) media. Furthermore, rDNA silencing was unaffected in the hxk2Δ, sch9Δ and tor1Δ genetic mimics of CR, but inhibited by FOB1 deletion. All these interventions extend lifespan in multiple yeast backgrounds, revealing a poor correlation between rDNA silencing and longevity. In contrast, CR and deletion of the FOB1, HXK2, SCH9 and TOR1 genes, all significantly reduced rDNA recombination. This silencing-independent mechanism for suppressing rDNA recombination may therefore contribute to CR-mediated lifespan extension.
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Affiliation(s)
- Michèle Riesen
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, UK
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