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Yamashita YM. Asymmetric Stem Cell Division and Germline Immortality. Annu Rev Genet 2023; 57:181-199. [PMID: 37552892 DOI: 10.1146/annurev-genet-022123-040039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Germ cells are the only cell type that is capable of transmitting genetic information to the next generation, which has enabled the continuation of multicellular life for the last 1.5 billion years. Surprisingly little is known about the mechanisms supporting the germline's remarkable ability to continue in this eternal cycle, termed germline immortality. Even unicellular organisms age at a cellular level, demonstrating that cellular aging is inevitable. Extensive studies in yeast have established the framework of how asymmetric cell division and gametogenesis may contribute to the resetting of cellular age. This review examines the mechanisms of germline immortality-how germline cells reset the aging of cells-drawing a parallel between yeast and multicellular organisms.
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Affiliation(s)
- Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Howard Hughes Medical Institute, and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
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2
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Enkhbaatar T, Skoneczny M, Stępień K, Mołoń M, Skoneczna A. Live while the DNA lasts. The role of autophagy in DNA loss and survival of diploid yeast cells during chronological aging. Aging (Albany NY) 2023; 15:9965-9983. [PMID: 37815879 PMCID: PMC10599738 DOI: 10.18632/aging.205102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/06/2023] [Indexed: 10/12/2023]
Abstract
Aging is inevitable and affects all cell types, thus yeast cells are often used as a model in aging studies. There are two approaches to studying aging in yeast: replicative aging, which describes the proliferative potential of cells, and chronological aging, which is used for studying post-mitotic cells. While analyzing the chronological lifespan (CLS) of diploid Saccharomyces cerevisiae cells, we discovered a remarkable phenomenon: ploidy reduction during aging progression. To uncover the mechanism behind this unusual process we used yeast strains undergoing a CLS assay, looking for various aging parameters. Cell mortality, regrowth ability, autophagy induction and cellular DNA content measurements indicated that during the CLS assay, dying cells lost their DNA, and only diploids survived. We demonstrated that autophagy was responsible for the gradual loss of DNA. The nucleophagy marker activation at the start of the CLS experiment correlated with the significant drop in cell viability. The activation of piecemeal microautophagy of nucleus (PMN) markers appeared to accompany the chronological aging process until the end. Our findings emphasize the significance of maintaining at least one intact copy of the genome for the survival of post-mitotic diploid cells. During chronological aging, cellular components, including DNA, are exposed to increasing stress, leading to DNA damage and fragmentation in aging cells. We propose that PMN-dependent clearance of damaged DNA from the nucleus helps prevent genome rearrangements. However, as long as one copy of the genome can be rebuilt, cells can still survive.
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Affiliation(s)
- Tuguldur Enkhbaatar
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Marek Skoneczny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Karolina Stępień
- Institute of Medical Sciences, Rzeszów University, Rzeszów 35-959, Poland
| | - Mateusz Mołoń
- Institute of Biology, Rzeszów University, Rzeszów 35-601, Poland
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
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3
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Paukštytė J, López Cabezas RM, Feng Y, Tong K, Schnyder D, Elomaa E, Gregorova P, Doudin M, Särkkä M, Sarameri J, Lippi A, Vihinen H, Juutila J, Nieminen A, Törönen P, Holm L, Jokitalo E, Krisko A, Huiskonen J, Sarin LP, Hietakangas V, Picotti P, Barral Y, Saarikangas J. Global analysis of aging-related protein structural changes uncovers enzyme-polymerization-based control of longevity. Mol Cell 2023; 83:3360-3376.e11. [PMID: 37699397 DOI: 10.1016/j.molcel.2023.08.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 05/18/2023] [Accepted: 08/11/2023] [Indexed: 09/14/2023]
Abstract
Aging is associated with progressive phenotypic changes. Virtually all cellular phenotypes are produced by proteins, and their structural alterations can lead to age-related diseases. However, we still lack comprehensive knowledge of proteins undergoing structural-functional changes during cellular aging and their contributions to age-related phenotypes. Here, we conducted proteome-wide analysis of early age-related protein structural changes in budding yeast using limited proteolysis-mass spectrometry (LiP-MS). The results, compiled in online ProtAge catalog, unraveled age-related functional changes in regulators of translation, protein folding, and amino acid metabolism. Mechanistically, we found that folded glutamate synthase Glt1 polymerizes into supramolecular self-assemblies during aging, causing breakdown of cellular amino acid homeostasis. Inhibiting Glt1 polymerization by mutating the polymerization interface restored amino acid levels in aged cells, attenuated mitochondrial dysfunction, and led to lifespan extension. Altogether, this comprehensive map of protein structural changes enables identifying mechanisms of age-related phenotypes and offers opportunities for their reversal.
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Affiliation(s)
- Jurgita Paukštytė
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Rosa María López Cabezas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Yuehan Feng
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Kai Tong
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Ellinoora Elomaa
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Pavlina Gregorova
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Matteo Doudin
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Meeri Särkkä
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Jesse Sarameri
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Alice Lippi
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Helena Vihinen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Juhana Juutila
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Anni Nieminen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Petri Törönen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Liisa Holm
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Eija Jokitalo
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Anita Krisko
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Juha Huiskonen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - L Peter Sarin
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Paola Picotti
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland; Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Yves Barral
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Juha Saarikangas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.
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4
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bin Imtiaz MK, Royall LN, Gonzalez-Bohorquez D, Jessberger S. Human neural progenitors establish a diffusion barrier in the endoplasmic reticulum membrane during cell division. Development 2022; 149:275957. [PMID: 35815653 PMCID: PMC9440750 DOI: 10.1242/dev.200613] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/20/2022] [Indexed: 11/20/2022]
Abstract
Asymmetric segregation of cellular components regulates the fate and behavior of somatic stem cells. Similar to dividing budding yeast and precursor cells in Caenorhabditis elegans, it has been shown that mouse neural progenitors establish a diffusion barrier in the membrane of the endoplasmic reticulum (ER), which has been associated with asymmetric partitioning of damaged proteins and cellular age. However, the existence of an ER diffusion barrier in human cells remains unknown. Here, we used fluorescence loss in photobleaching (FLIP) imaging to show that human embryonic stem cell (hESC)- and induced pluripotent stem cell (iPSC)-derived neural progenitor cells establish an ER diffusion barrier during cell division. The human ER diffusion barrier is regulated via lamin-dependent mechanisms and is associated with asymmetric segregation of mono- and polyubiquitylated damaged proteins. Further, forebrain regionalized organoids derived from hESCs were used to show the establishment of an ER membrane diffusion barrier in more naturalistic tissues, mimicking early steps of human brain development. Thus, the data provided here show that human neural progenitors establish a diffusion barrier during cell division in the membrane of the ER, which may allow for asymmetric segregation of cellular components, contributing to the fate and behavior of human neural progenitor cells. Summary: Asymmetric segregation of cellular components, which may contribute to the fate and behavior of human neural progenitors, is allowed by a diffusion barrier in the endoplasmic reticulum membrane during cell division.
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Affiliation(s)
- Muhammad Khadeesh bin Imtiaz
- Laboratory of Neural Plasticity , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
- Brain Research Institute, University of Zurich , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
| | - Lars N. Royall
- Laboratory of Neural Plasticity , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
- Brain Research Institute, University of Zurich , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
| | - Daniel Gonzalez-Bohorquez
- Laboratory of Neural Plasticity , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
- Brain Research Institute, University of Zurich , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
| | - Sebastian Jessberger
- Laboratory of Neural Plasticity , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
- Brain Research Institute, University of Zurich , Faculties of Medicine and Science , , 8057 Zurich , Switzerland
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5
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Schnitzer B, Österberg L, Skopa I, Cvijovic M. Multi-scale model suggests the trade-off between protein and ATP demand as a driver of metabolic changes during yeast replicative ageing. PLoS Comput Biol 2022; 18:e1010261. [PMID: 35797415 PMCID: PMC9295998 DOI: 10.1371/journal.pcbi.1010261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/19/2022] [Accepted: 05/31/2022] [Indexed: 11/18/2022] Open
Abstract
The accumulation of protein damage is one of the major drivers of replicative ageing, describing a cell’s reduced ability to reproduce over time even under optimal conditions. Reactive oxygen and nitrogen species are precursors of protein damage and therefore tightly linked to ageing. At the same time, they are an inevitable by-product of the cell’s metabolism. Cells are able to sense high levels of reactive oxygen and nitrogen species and can subsequently adapt their metabolism through gene regulation to slow down damage accumulation. However, the older or damaged a cell is the less flexibility it has to allocate enzymes across the metabolic network, forcing further adaptions in the metabolism. To investigate changes in the metabolism during replicative ageing, we developed an multi-scale mathematical model using budding yeast as a model organism. The model consists of three interconnected modules: a Boolean model of the signalling network, an enzyme-constrained flux balance model of the central carbon metabolism and a dynamic model of growth and protein damage accumulation with discrete cell divisions. The model can explain known features of replicative ageing, like average lifespan and increase in generation time during successive division, in yeast wildtype cells by a decreasing pool of functional enzymes and an increasing energy demand for maintenance. We further used the model to identify three consecutive metabolic phases, that a cell can undergo during its life, and their influence on the replicative potential, and proposed an intervention span for lifespan control.
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Affiliation(s)
- Barbara Schnitzer
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Linnea Österberg
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Iro Skopa
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Marija Cvijovic
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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6
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Genetic and Epigenetic Inheritance at Telomeres. EPIGENOMES 2022; 6:epigenomes6010009. [PMID: 35323213 PMCID: PMC8947350 DOI: 10.3390/epigenomes6010009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/21/2022] [Accepted: 03/08/2022] [Indexed: 12/17/2022] Open
Abstract
Transgenerational inheritance can occur at telomeres in distinct contexts. Deficiency for telomerase or telomere-binding proteins in germ cells can result in shortened or lengthened chromosome termini that are transmitted to progeny. In human families, altered telomere lengths can result in stem cell dysfunction or tumor development. Genetic inheritance of altered telomeres as well as mutations that alter telomeres can result in progressive telomere length changes over multiple generations. Telomeres of yeast can modulate the epigenetic state of subtelomeric genes in a manner that is mitotically heritable, and the effects of telomeres on subtelomeric gene expression may be relevant to senescence or other human adult-onset disorders. Recently, two novel epigenetic states were shown to occur at C. elegans telomeres, where very low or high levels of telomeric protein foci can be inherited for multiple generations through a process that is regulated by histone methylation.Together, these observations illustrate that information relevant to telomere biology can be inherited via genetic and epigenetic mechanisms, although the broad impact of epigenetic inheritance to human biology remains unclear.
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7
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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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8
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Schnitzer B, Borgqvist J, Cvijovic M. The synergy of damage repair and retention promotes rejuvenation and prolongs healthy lifespans in cell lineages. PLoS Comput Biol 2020; 16:e1008314. [PMID: 33044956 PMCID: PMC7598927 DOI: 10.1371/journal.pcbi.1008314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 10/30/2020] [Accepted: 09/04/2020] [Indexed: 01/29/2023] Open
Abstract
Damaged proteins are inherited asymmetrically during cell division in the yeast Saccharomyces cerevisiae, such that most damage is retained within the mother cell. The consequence is an ageing mother and a rejuvenated daughter cell with full replicative potential. Daughters of old and damaged mothers are however born with increasing levels of damage resulting in lowered replicative lifespans. Remarkably, these prematurely old daughters can give rise to rejuvenated cells with low damage levels and recovered lifespans, called second-degree rejuvenation. We aimed to investigate how damage repair and retention together can promote rejuvenation and at the same time ensure low damage levels in mother cells, reflected in longer health spans. We developed a dynamic model for damage accumulation over successive divisions in individual cells as part of a dynamically growing cell lineage. With detailed knowledge about single-cell dynamics and relationships between all cells in the lineage, we can infer how individual damage repair and retention strategies affect the propagation of damage in the population. We show that damage retention lowers damage levels in the population by reducing the variability across the lineage, and results in larger population sizes. Repairing damage efficiently in early life, as opposed to investing in repair when damage has already accumulated, counteracts accelerated ageing caused by damage retention. It prolongs the health span of individual cells which are moreover less prone to stress. In combination, damage retention and early investment in repair are beneficial for healthy ageing in yeast cell populations.
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Affiliation(s)
- Barbara Schnitzer
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden
| | - Johannes Borgqvist
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden
| | - Marija Cvijovic
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden
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9
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Mattiazzi Usaj M, Sahin N, Friesen H, Pons C, Usaj M, Masinas MPD, Shuteriqi E, Shkurin A, Aloy P, Morris Q, Boone C, Andrews BJ. Systematic genetics and single-cell imaging reveal widespread morphological pleiotropy and cell-to-cell variability. Mol Syst Biol 2020; 16:e9243. [PMID: 32064787 PMCID: PMC7025093 DOI: 10.15252/msb.20199243] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/16/2019] [Accepted: 01/15/2020] [Indexed: 12/13/2022] Open
Abstract
Our ability to understand the genotype-to-phenotype relationship is hindered by the lack of detailed understanding of phenotypes at a single-cell level. To systematically assess cell-to-cell phenotypic variability, we combined automated yeast genetics, high-content screening and neural network-based image analysis of single cells, focussing on genes that influence the architecture of four subcellular compartments of the endocytic pathway as a model system. Our unbiased assessment of the morphology of these compartments-endocytic patch, actin patch, late endosome and vacuole-identified 17 distinct mutant phenotypes associated with ~1,600 genes (~30% of all yeast genes). Approximately half of these mutants exhibited multiple phenotypes, highlighting the extent of morphological pleiotropy. Quantitative analysis also revealed that incomplete penetrance was prevalent, with the majority of mutants exhibiting substantial variability in phenotype at the single-cell level. Our single-cell analysis enabled exploration of factors that contribute to incomplete penetrance and cellular heterogeneity, including replicative age, organelle inheritance and response to stress.
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Affiliation(s)
| | - Nil Sahin
- The Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | | | - Carles Pons
- Institute for Research in Biomedicine (IRB Barcelona)The Barcelona Institute for Science and TechnologyBarcelona, CataloniaSpain
| | - Matej Usaj
- The Donnelly CentreUniversity of TorontoTorontoONCanada
| | | | | | - Aleksei Shkurin
- The Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Patrick Aloy
- Institute for Research in Biomedicine (IRB Barcelona)The Barcelona Institute for Science and TechnologyBarcelona, CataloniaSpain
- Institució Catalana de Recerca i Estudis Avançats (ICREA)Barcelona, CataloniaSpain
| | - Quaid Morris
- The Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
- Computational and Systems Biology ProgramMemorial Sloan Kettering Cancer CenterNew YorkNYUSA
| | - Charles Boone
- The Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
- RIKEN Centre for Sustainable Resource ScienceWakoSaitamaJapan
| | - Brenda J Andrews
- The Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
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10
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Synergistic effects of repair, resilience and retention of damage determine the conditions for replicative ageing. Sci Rep 2020; 10:1556. [PMID: 32005954 PMCID: PMC6994596 DOI: 10.1038/s41598-020-58444-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 01/15/2020] [Indexed: 12/31/2022] Open
Abstract
Accumulation of damaged proteins is a hallmark of ageing, occurring in organisms ranging from bacteria and yeast to mammalian cells. During cell division in Saccharomyces cerevisiae, damaged proteins are retained within the mother cell, resulting in an ageing mother while a new daughter cell exhibits full replicative potential. The cell-specific features determining the ageing remain elusive. It has been suggested that the replicative ageing is dependent on the ability of the cell to repair and retain pre-existing damage. To deepen the understanding of how these factors influence the life of individual cells, we developed and experimentally validated a dynamic model of damage accumulation accounting for replicative ageing on the single cell level. The model includes five essential properties: cell growth, damage formation, damage repair, cell division and cell death, represented in a theoretical framework describing the conditions allowing for replicative ageing, starvation, immortality or clonal senescence. We introduce the resilience to damage, which can be interpreted as the difference in volume between an old and a young cell. We show that the capacity to retain damage deteriorates with high age, that asymmetric division allows for retention of damage, and that there is a trade-off between retention and the resilience property. Finally, we derive the maximal degree of asymmetry as a function of resilience, proposing that asymmetric cell division is beneficial with respect to replicative ageing as it increases the lifespan of a given organism. The proposed model contributes to a deeper understanding of the ageing process in eukaryotic organisms.
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11
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Denoth-Lippuner A, Jessberger S. Mechanisms of cellular rejuvenation. FEBS Lett 2019; 593:3381-3392. [PMID: 31197818 DOI: 10.1002/1873-3468.13483] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/29/2019] [Accepted: 05/02/2019] [Indexed: 01/15/2023]
Abstract
Aging leads to changes on an organismal but also cellular level. However, the exact mechanisms of cellular aging in mammals remain poorly understood and the identity and functional role of aging factors, some of which have previously been defined in model organisms such as Saccharomyces cerevisiae, remain elusive. Remarkably, during cellular reprogramming most if not all aging hallmarks are erased, offering a novel entry point to study aging and rejuvenation on a cellular level. On the other hand, direct reprogramming of old cells into cells of a different fate preserves many aging signs. Therefore, investigating the process of reprogramming and comparing it to direct reprogramming may yield novel insights about the clearing of aging factors, which is the basis of rejuvenation. Here, we discuss how reprogramming might lead to rejuvenation of a cell, an organ, or even the whole organism.
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Affiliation(s)
- Annina Denoth-Lippuner
- Laboratory of Neural Plasticity, Faculties of Medicine and Science, Brain Research Institute, University of Zurich, Switzerland
| | - Sebastian Jessberger
- Laboratory of Neural Plasticity, Faculties of Medicine and Science, Brain Research Institute, University of Zurich, Switzerland
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12
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Jin M, Li Y, O'Laughlin R, Bittihn P, Pillus L, Tsimring LS, Hasty J, Hao N. Divergent Aging of Isogenic Yeast Cells Revealed through Single-Cell Phenotypic Dynamics. Cell Syst 2019; 8:242-253.e3. [PMID: 30852250 DOI: 10.1016/j.cels.2019.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/28/2018] [Accepted: 02/07/2019] [Indexed: 12/27/2022]
Abstract
Although genetic mutations that alter organisms' average lifespans have been identified in aging research, our understanding of the dynamic changes during aging remains limited. Here, we integrate single-cell imaging, microfluidics, and computational modeling to investigate phenotypic divergence and cellular heterogeneity during replicative aging of single S. cerevisiae cells. Specifically, we find that isogenic cells diverge early in life toward one of two aging paths, which are characterized by distinct age-associated phenotypes. We captured the dynamics of single cells along the paths with a stochastic discrete-state model, which accurately predicts both the measured heterogeneity and the lifespan of cells on each path within a cell population. Our analysis suggests that genetic and environmental factors influence both a cell's choice of paths and the kinetics of paths themselves. Given that these factors are highly conserved throughout eukaryotes, divergent aging might represent a general scheme in cellular aging of other organisms.
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Affiliation(s)
- Meng Jin
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Yang Li
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Richard O'Laughlin
- Department of Bioengineering, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Philip Bittihn
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Lorraine Pillus
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; UCSD Moores Cancer Center, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Lev S Tsimring
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
| | - Jeff Hasty
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; Department of Bioengineering, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
| | - Nan Hao
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
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13
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Knorre DA, Azbarova AV, Galkina KV, Feniouk BA, Severin FF. Replicative aging as a source of cell heterogeneity in budding yeast. Mech Ageing Dev 2018; 176:24-31. [DOI: 10.1016/j.mad.2018.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 02/06/2023]
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14
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High-Reynolds Microfluidic Sorting of Large Yeast Populations. Sci Rep 2018; 8:13739. [PMID: 30214051 PMCID: PMC6137188 DOI: 10.1038/s41598-018-31726-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 08/02/2018] [Indexed: 12/24/2022] Open
Abstract
Microfluidic sorting offers a unique ability to isolate large numbers of cells for bulk proteomic or metabolomics studies but is currently limited by low throughput and persistent clogging at low flow rates. Recently we uncovered the physical principles governing the inertial focusing of particles in high-Reynolds numbers. Here, we superimpose high Reynolds inertial focusing on Dean vortices, to rapidly isolate large quantities of young and adult yeast from mixed populations at a rate of 107 cells/min/channel. Using a new algorithm to rapidly quantify budding scars in isolated yeast populations and system-wide proteomic analysis, we demonstrate that protein quality control and expression of established yeast aging markers such as CalM, RPL5, and SAM1 may change after the very first replication events, rather than later in the aging process as previously thought. Our technique enables the large-scale isolation of microorganisms based on minute differences in size (±1.5 μm), a feat unmatched by other technologies.
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15
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Molon M, Panek A, Molestak E, Skoneczny M, Tchorzewski M, Wnuk M. Daughters of the budding yeast from old mothers have shorter replicative lifespans but not total lifespans. Are DNA damage and rDNA instability the factors that determine longevity? Cell Cycle 2018; 17:1173-1187. [PMID: 29895191 DOI: 10.1080/15384101.2018.1464846] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Although a lot of effort has been put into the search for factors responsible for aging in yeast mother cells, our knowledge of cellular changes in daughter cells originating from old mothers is still very limited. It has been shown that an old mother is not able to compensate for all negative changes within its cell and therefore transfers them to the bud. In this paper, we show for the first time that daughter cells of an old mother have a reset lifespan expressed in units of time despite drastic reduction of their budding lifespan, which suggests that a single yeast cell has a fixed programmed longevity regardless of the time point at which it was originated. Moreover, in our study we found that longevity parameters are not correlated with the rDNA level, DNA damage, chromosome structure or aging parameters (budding lifespan and total lifespan).
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Affiliation(s)
- Mateusz Molon
- a Department of Biochemistry and Cell Biology , University of Rzeszow , Rzeszow , Poland
| | - Anita Panek
- b Department of Genetics , University of Rzeszow , Rzeszow , Poland
| | - Eliza Molestak
- c Department of Molecular Biology , Maria Curie-Sklodowska University , Lublin , Poland
| | - Marek Skoneczny
- d Department of Genetics , Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Warsaw , Poland
| | - Marek Tchorzewski
- c Department of Molecular Biology , Maria Curie-Sklodowska University , Lublin , Poland
| | - Maciej Wnuk
- b Department of Genetics , University of Rzeszow , Rzeszow , Poland
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16
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Harkness TAA. Activating the Anaphase Promoting Complex to Enhance Genomic Stability and Prolong Lifespan. Int J Mol Sci 2018; 19:ijms19071888. [PMID: 29954095 PMCID: PMC6073722 DOI: 10.3390/ijms19071888] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 12/19/2022] Open
Abstract
In aging cells, genomic instability is now recognized as a hallmark event. Throughout life, cells encounter multiple endogenous and exogenous DNA damaging events that are mostly repaired, but inevitably DNA mutations, chromosome rearrangements, and epigenetic deregulation begins to mount. Now that people are living longer, more and more late life time is spent suffering from age-related disease, in which genomic instability plays a critical role. However, several major questions remain heavily debated, such as the following: When does aging start? How long can we live? In order to minimize the impact of genomic instability on longevity, it is important to understand when aging starts, and to ensure repair mechanisms remain optimal from the very start to the very end. In this review, the interplay between the stress and nutrient response networks, and the regulation of homeostasis and genomic stability, is discussed. Mechanisms that link these two networks are predicted to be key lifespan determinants. The Anaphase Promoting Complex (APC), a large evolutionarily conserved ubiquitin ligase, can potentially serve this need. Recent work demonstrates that the APC maintains genomic stability, mounts a stress response, and increases longevity in yeast. Furthermore, inhibition of APC activity by glucose and nutrient response factors indicates a tight link between the APC and the stress/nutrient response networks.
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Affiliation(s)
- Troy A A Harkness
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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17
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Jones SK, Spivey EC, Rybarski JR, Finkelstein IJ. A Microfluidic Device for Massively Parallel, Whole-lifespan Imaging of Single Fission Yeast Cells. Bio Protoc 2018; 8:e2783. [PMID: 29770351 DOI: 10.21769/bioprotoc.2783] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Whole-lifespan single-cell analysis has greatly increased our understanding of fundamental cellular processes such as cellular aging. To observe individual cells across their entire lifespan, all progeny must be removed from the growth medium, typically via manual microdissection. However, manual microdissection is laborious, low-throughput, and incompatible with fluorescence microscopy. Here, we describe assembly and operation of the multiplexed-Fission Yeast Lifespan Microdissector (multFYLM), a high-throughput microfluidic device for rapidly acquiring single-cell whole-lifespan imaging. multFYLM captures approximately one thousand rod-shaped fission yeast cells from up to six different genetic backgrounds or treatment regimens. The immobilized cells are fluorescently imaged for over a week, while the progeny cells are removed from the device. The resulting datasets yield high-resolution multi-channel images that record each cell's replicative lifespan. We anticipate that the multFYLM will be broadly applicable for single-cell whole-lifespan studies in the fission yeast (Schizosaccharomyces pombe) and other symmetrically-dividing unicellular organisms.
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Affiliation(s)
- Stephen K Jones
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Eric C Spivey
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - James R Rybarski
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
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18
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Baldi S, Bolognesi A, Meinema AC, Barral Y. Heat stress promotes longevity in budding yeast by relaxing the confinement of age-promoting factors in the mother cell. eLife 2017; 6:28329. [PMID: 29283340 PMCID: PMC5771669 DOI: 10.7554/elife.28329] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 12/27/2017] [Indexed: 12/16/2022] Open
Abstract
Although individuals of many species inexorably age, a number of observations established that the rate of aging is modulated in response to a variety of mild stresses. Here, we investigated how heat stress promotes longevity in yeast. We show that upon growth at higher temperature, yeast cells relax the retention of DNA circles, which act as aging factors in the mother cell. The enhanced frequency at which circles redistribute to daughter cells was not due to changes of anaphase duration or nuclear shape but solely to the downregulation of the diffusion barrier in the nuclear envelope. This effect depended on the PKA and Tor1 pathways, downstream of stress-response kinase Pkc1. Inhibition of these responses restored barrier function and circle retention and abrogated the effect of heat stress on longevity. Our data indicate that redistribution of aging factors from aged cells to their progeny can be a mechanism for modulating longevity.
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Affiliation(s)
- Sandro Baldi
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Alessio Bolognesi
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | | | - Yves Barral
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
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19
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Mena A, Medina DA, García-Martínez J, Begley V, Singh A, Chávez S, Muñoz-Centeno MC, Pérez-Ortín JE. Asymmetric cell division requires specific mechanisms for adjusting global transcription. Nucleic Acids Res 2017; 45:12401-12412. [PMID: 29069448 PMCID: PMC5716168 DOI: 10.1093/nar/gkx974] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/10/2017] [Indexed: 12/19/2022] Open
Abstract
Most cells divide symmetrically into two approximately identical cells. There are many examples, however, of asymmetric cell division that can generate sibling cell size differences. Whereas physical asymmetric division mechanisms and cell fate consequences have been investigated, the specific problem caused by asymmetric division at the transcription level has not yet been addressed. In symmetrically dividing cells the nascent transcription rate increases in parallel to cell volume to compensate it by keeping the actual mRNA synthesis rate constant. This cannot apply to the yeast Saccharomyces cerevisiae, where this mechanism would provoke a never-ending increasing mRNA synthesis rate in smaller daughter cells. We show here that, contrarily to other eukaryotes with symmetric division, budding yeast keeps the nascent transcription rates of its RNA polymerases constant and increases mRNA stability. This control on RNA pol II-dependent transcription rate is obtained by controlling the cellular concentration of this enzyme.
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Affiliation(s)
- Adriana Mena
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
| | - Daniel A Medina
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
| | - José García-Martínez
- Departamento de Genética and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
| | - Victoria Begley
- Departamento de Genética, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, 41013 Sevilla, Spain
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716, USA
| | - Sebastián Chávez
- Departamento de Genética, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, 41013 Sevilla, Spain
| | - Mari C Muñoz-Centeno
- Departamento de Genética, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, 41013 Sevilla, Spain
| | - José E Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
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20
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Singh P, Li R. Emerging roles for sphingolipids in cellular aging. Curr Genet 2017; 64:761-767. [PMID: 29260307 DOI: 10.1007/s00294-017-0799-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 02/07/2023]
Abstract
Aging is a gradual loss of physiological functions as organisms' progress in age. Although aging in multicellular organisms is complex, some fundamental mechanisms and pathways may be shared from the single cellular yeast to human. Budding yeast Saccharomyces cerevisiae has been established model system for aging studies. A yeast cell divides asymmetrically to produce two cells that differ in size and age. The one that is smaller coming from bud is a newborn cell that with a full replicative potential head irrespective of the replicative age of its mother-the larger cell from which the bud grows out before division. The age asymmetry between daughter and mother is thought to be dependent on asymmetric segregation of certain factors such as protein aggregates, extrachromosomal DNA (ERCs) and dysfunctional organelles during successive cell divisions of the yeast replicative lifespan (RLS). It is also thought that certain plasma membrane proteins, in particular multidrug-resistant (MDR) proteins, asymmetrically partition between the mother and the bud based on the age of the polypeptides. Functional decline associated with the molecular aging of those proteins contributes to the fitness decline at advance age. In our recent study, we showed that sphingolipids facilitate the age-dependent segregation of MDRs between daughter and mother cell. In this review, we highlight and discuss the potential mechanisms by which sphingolipids regulate the aging process in yeast and cells of vertebrate animals including human.
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Affiliation(s)
- Pushpendra Singh
- Laboratory of Adjuvant and Antigen Research, US Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA. .,US Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD, 20817, USA.
| | - Rong Li
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
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21
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Singh P, Ramachandran SK, Zhu J, Kim BC, Biswas D, Ha T, Iglesias PA, Li R. Sphingolipids facilitate age asymmetry of membrane proteins in dividing yeast cells. Mol Biol Cell 2017; 28:2712-2722. [PMID: 28768828 PMCID: PMC5620378 DOI: 10.1091/mbc.e17-05-0335] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/21/2017] [Accepted: 07/28/2017] [Indexed: 01/20/2023] Open
Abstract
One proposed mechanism of cellular aging is the gradual loss of certain cellular components that are insufficiently renewed. In an earlier study, multidrug resistance transporters (MDRs) were postulated to be such aging determinants during the yeast replicative life span (RLS). Aged MDR proteins were asymmetrically retained by the aging mother cell and did not diffuse freely into the bud, whereas newly synthesized MDR proteins were thought to be deposited mostly in the bud before cytokinesis. In this study, we further demonstrate the proposed age asymmetry of MDR proteins in dividing yeast cells and investigate the mechanism that controls diffusive properties of MDR proteins to maintain this asymmetry. We found that long-chain sphingolipids, but not the septin/endoplasmic reticulum-based membrane diffusion barrier, are important for restricting MDR diffusion. Depletion of sphingolipids or shortening of their long acyl chains resulted in an increase in the lateral mobility of MDR proteins, causing aged MDR protein in the mother cell to enter the bud. We used a mathematical model to understand the effect of diminished MDR age asymmetry on yeast cell aging, the result of which was qualitatively consistent with the observed RLS shortening in sphingolipid mutants.
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Affiliation(s)
- Pushpendra Singh
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Sree Kumar Ramachandran
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Jin Zhu
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Byoung Choul Kim
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218.,Howard Hughes Medical Institute, Baltimore, MD 21218.,Division of Nano-bioengineering, Incheon National University, Incheon 22012, Republic of Korea
| | - Debojyoti Biswas
- Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218.,Howard Hughes Medical Institute, Baltimore, MD 21218
| | - Pablo A Iglesias
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218.,Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Rong Li
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 .,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
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22
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Böckler S, Chelius X, Hock N, Klecker T, Wolter M, Weiss M, Braun RJ, Westermann B. Fusion, fission, and transport control asymmetric inheritance of mitochondria and protein aggregates. J Cell Biol 2017; 216:2481-2498. [PMID: 28615194 PMCID: PMC5551707 DOI: 10.1083/jcb.201611197] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 04/13/2017] [Accepted: 05/12/2017] [Indexed: 12/18/2022] Open
Abstract
Asymmetric inheritance of cell organelles determines the fate of daughter cells. Böckler et al. use yeast as a model to demonstrate that the dynamics of mitochondrial fusion, fission, and transport determine partitioning of mitochondria and cytosolic protein aggregates, which is critical for rejuvenation of daughter cells. Partitioning of cell organelles and cytoplasmic components determines the fate of daughter cells upon asymmetric division. We studied the role of mitochondria in this process using budding yeast as a model. Anterograde mitochondrial transport is mediated by the myosin motor, Myo2. A genetic screen revealed an unexpected interaction of MYO2 and genes required for mitochondrial fusion. Genetic analyses, live-cell microscopy, and simulations in silico showed that fused mitochondria become critical for inheritance and transport across the bud neck in myo2 mutants. Similarly, fused mitochondria are essential for retention in the mother when bud-directed transport is enforced. Inheritance of a less than critical mitochondrial quantity causes a severe decline of replicative life span of daughter cells. Myo2-dependent mitochondrial distribution also is critical for the capture of heat stress–induced cytosolic protein aggregates and their retention in the mother cell. Together, these data suggest that coordination of mitochondrial transport, fusion, and fission is critical for asymmetric division and rejuvenation of daughter cells.
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Affiliation(s)
| | - Xenia Chelius
- Zellbiologie, Universität Bayreuth, Bayreuth, Germany
| | - Nadine Hock
- Zellbiologie, Universität Bayreuth, Bayreuth, Germany
| | - Till Klecker
- Zellbiologie, Universität Bayreuth, Bayreuth, Germany
| | - Madita Wolter
- Zellbiologie, Universität Bayreuth, Bayreuth, Germany
| | - Matthias Weiss
- Experimentalphysik I, Universität Bayreuth, Bayreuth, Germany
| | - Ralf J Braun
- Zellbiologie, Universität Bayreuth, Bayreuth, Germany
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23
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Bilinski T, Bylak A, Zadrag-Tecza R. The budding yeast Saccharomyces cerevisiae as a model organism: possible implications for gerontological studies. Biogerontology 2017; 18:631-640. [PMID: 28573416 PMCID: PMC5514200 DOI: 10.1007/s10522-017-9712-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/19/2017] [Indexed: 12/15/2022]
Abstract
Experimental gerontology is based on the fundamental assumption that the aging process has a universal character and that the mechanisms of aging are well-conserved among living things. The consequence of this assumption is the use of various organisms, including unicellular yeast Saccharomyces cerevisiae, as models in gerontology, and direct extrapolation of the conclusions drawn from the studies carried on these organisms to human beings. However, numerous arguments suggest that aging is not universal and its mechanisms are not conserved in a wide range of species. Instead, senescence can be treated as a side effect of the evolution of specific features for systematic group, unrelated to the passage of time. Hence, depending on the properties of the group, the senescence and proximal causes of death could have a diverse nature. We postulate that the selection of a model organism to explain the mechanism of human aging and human longevity should be preceded by the analysis of its potential to extrapolate the results to a wide group of organisms. Considering that gerontology is a human-oriented discipline and that aging involves complex, systemic changes affecting the entire organism, the object of experimental studies should be animals which are closest relatives of human beings in evolutionary terms, rather than lower organisms, which do not have sufficient complexity in terms of tissues and organ structures.
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Affiliation(s)
- Tomasz Bilinski
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland
| | - Aneta Bylak
- Department of Ecology and Environmental 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.
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24
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Mitochondria-organelle contact sites: the plot thickens. Biochem Soc Trans 2017; 45:477-488. [PMID: 28408488 DOI: 10.1042/bst20160130] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/07/2017] [Accepted: 02/13/2017] [Indexed: 01/30/2023]
Abstract
Membrane contact sites (MCSs) are areas of close apposition between the membranes of two different organelles that enable non-vesicular transfer of ions and lipids. Recent studies reveal that mitochondria maintain contact sites with organelles other than the endoplasmic reticulum such as the vacuole, plasma membrane and peroxisomes. This review focuses on novel findings achieved mainly in yeast regarding tethers, function and regulation of mitochondria-organelle contact sites. The emerging network of MCSs linking virtually all cellular organelles is highly dynamic and integrated with cellular metabolism.
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25
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Spivey EC, Jones SK, Rybarski JR, Saifuddin FA, Finkelstein IJ. An aging-independent replicative lifespan in a symmetrically dividing eukaryote. eLife 2017; 6:e20340. [PMID: 28139976 PMCID: PMC5332158 DOI: 10.7554/elife.20340] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/27/2017] [Indexed: 12/28/2022] Open
Abstract
The replicative lifespan (RLS) of a cell-defined as the number of cell divisions before death-has informed our understanding of the mechanisms of cellular aging. However, little is known about aging and longevity in symmetrically dividing eukaryotic cells because most prior studies have used budding yeast for RLS studies. Here, we describe a multiplexed fission yeast lifespan micro-dissector (multFYLM) and an associated image processing pipeline for performing high-throughput and automated single-cell micro-dissection. Using the multFYLM, we observe continuous replication of hundreds of individual fission yeast cells for over seventy-five generations. Surprisingly, cells die without the classic hallmarks of cellular aging, such as progressive changes in size, doubling time, or sibling health. Genetic perturbations and drugs can extend the RLS via an aging-independent mechanism. Using a quantitative model to analyze these results, we conclude that fission yeast does not age and that cellular aging and replicative lifespan can be uncoupled in a eukaryotic cell.
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Affiliation(s)
- Eric C Spivey
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, United States
| | - Stephen K Jones
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, United States
| | - James R Rybarski
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Fatema A Saifuddin
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, United States
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States
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26
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Güven E, Parnell LA, Jackson ED, Parker MC, Gupta N, Rodrigues J, Qin H. Hydrogen peroxide induced loss of heterozygosity correlates with replicative lifespan and mitotic asymmetry in Saccharomyces cerevisiae. PeerJ 2016; 4:e2671. [PMID: 27833823 PMCID: PMC5101604 DOI: 10.7717/peerj.2671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/09/2016] [Indexed: 01/28/2023] Open
Abstract
Cellular aging in Saccharomyces cerevisiae can lead to genomic instability and impaired mitotic asymmetry. To investigate the role of oxidative stress in cellular aging, we examined the effect of exogenous hydrogen peroxide on genomic instability and mitotic asymmetry in a collection of yeast strains with diverse backgrounds. We treated yeast cells with hydrogen peroxide and monitored the changes of viability and the frequencies of loss of heterozygosity (LOH) in response to hydrogen peroxide doses. The mid-transition points of viability and LOH were quantified using sigmoid mathematical functions. We found that the increase of hydrogen peroxide dependent genomic instability often occurs before a drop in viability. We previously observed that elevation of genomic instability generally lags behind the drop in viability during chronological aging. Hence, onset of genomic instability induced by exogenous hydrogen peroxide treatment is opposite to that induced by endogenous oxidative stress during chronological aging, with regards to the midpoint of viability. This contrast argues that the effect of endogenous oxidative stress on genome integrity is well suppressed up to the dying-off phase during chronological aging. We found that the leadoff of exogenous hydrogen peroxide induced genomic instability to viability significantly correlated with replicative lifespan (RLS), indicating that yeast cells' ability to counter oxidative stress contributes to their replicative longevity. Surprisingly, this leadoff is positively correlated with an inverse measure of endogenous mitotic asymmetry, indicating a trade-off between mitotic asymmetry and cell's ability to fend off hydrogen peroxide induced oxidative stress. Overall, our results demonstrate strong associations of oxidative stress to genomic instability and mitotic asymmetry at the population level of budding yeast.
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Affiliation(s)
- Emine Güven
- Department of Biology, Spelman College, Atlanta, Georgia, United States
- Current affiliation: Department of Computer Science and Engineering, University of Tennessee at Chattanooga, Chattanooga, Tennessee, United States
| | - Lindsay A. Parnell
- Department of Biology, Spelman College, Atlanta, Georgia, United States
- Current affiliation: Program of Molecular Genetics and Genomics, Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Erin D. Jackson
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Meighan C. Parker
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Nilin Gupta
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Jenny Rodrigues
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Hong Qin
- Department of Biology, Spelman College, Atlanta, Georgia, United States
- Current affiliation: Department of Computer Science and Engineering, Department of Biology, Geology, and Environmental Science, SimCenter, University of Tennessee at Chattanooga, Chattanooga, Tennessee, United States
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27
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Kim Y, Nam HG, Valenzano DR. The short-lived African turquoise killifish: an emerging experimental model for ageing. Dis Model Mech 2016; 9:115-29. [PMID: 26839399 PMCID: PMC4770150 DOI: 10.1242/dmm.023226] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model.
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Affiliation(s)
- Yumi Kim
- Max Planck Institute for Biology of Ageing, D50931, Cologne, Germany Department of New Biology, DGIST, 711-873, Daegu, Republic of Korea
| | - Hong Gil Nam
- Department of New Biology, DGIST, 711-873, Daegu, Republic of Korea Center for Plant Aging Research, Institute for Basic Science, 711-873, Daegu, Republic of Korea
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28
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Moore DL, Jessberger S. Creating Age Asymmetry: Consequences of Inheriting Damaged Goods in Mammalian Cells. Trends Cell Biol 2016; 27:82-92. [PMID: 27717533 DOI: 10.1016/j.tcb.2016.09.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 09/10/2016] [Accepted: 09/13/2016] [Indexed: 12/15/2022]
Abstract
Accumulating evidence suggests that mammalian cells asymmetrically segregate cellular components ranging from genomic DNA to organelles and damaged proteins during cell division. Asymmetric inheritance upon mammalian cell division may be specifically important to ensure cellular fitness and propagate cellular potency to individual progeny, for example in the context of somatic stem cell division. We review here recent advances in the field and discuss potential effects and underlying mechanisms that mediate asymmetric segregation of cellular components during mammalian cell division.
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Affiliation(s)
- Darcie L Moore
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA.
| | - Sebastian Jessberger
- Brain Research Institute, Faculty of Medicine and Science, University of Zurich, 8057 Zurich, Switzerland.
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29
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Liu YT, Chang KM, Ma CH, Jayaram M. Replication-dependent and independent mechanisms for the chromosome-coupled persistence of a selfish genome. Nucleic Acids Res 2016; 44:8302-23. [PMID: 27492289 PMCID: PMC5041486 DOI: 10.1093/nar/gkw694] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 12/21/2022] Open
Abstract
The yeast 2-micron plasmid epitomizes the evolutionary optimization of selfish extra-chromosomal genomes for stable persistence without jeopardizing their hosts' fitness. Analyses of fluorescence-tagged single-copy reporter plasmids and/or the plasmid partitioning proteins in native and non-native hosts reveal chromosome-hitchhiking as the likely means for plasmid segregation. The contribution of the partitioning system to equal segregation is bipartite- replication-independent and replication-dependent. The former nearly eliminates 'mother bias' (preferential plasmid retention in the mother cell) according to binomial distribution, thus limiting equal segregation of a plasmid pair to 50%. The latter enhances equal segregation of plasmid sisters beyond this level, elevating the plasmid close to chromosome status. Host factors involved in plasmid partitioning can be functionally separated by their participation in the replication-independent and/or replication-dependent steps. In the hitchhiking model, random tethering of a pair of plasmids to chromosomes signifies the replication-independent component of segregation; the symmetric tethering of plasmid sisters to sister chromatids embodies the replication-dependent component. The 2-micron circle broadly resembles the episomes of certain mammalian viruses in its chromosome-associated propagation. This unifying feature among otherwise widely differing selfish genomes suggests their evolutionary convergence to the common logic of exploiting, albeit via distinct molecular mechanisms, host chromosome segregation machineries for self-preservation.
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Affiliation(s)
- Yen-Ting Liu
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Keng-Ming Chang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Chien-Hui Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Makkuni Jayaram
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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30
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Abraham KJ, Chan JNY, Salvi JS, Ho B, Hall A, Vidya E, Guo R, Killackey SA, Liu N, Lee JE, Brown GW, Mekhail K. Intersection of calorie restriction and magnesium in the suppression of genome-destabilizing RNA-DNA hybrids. Nucleic Acids Res 2016; 44:8870-8884. [PMID: 27574117 PMCID: PMC5063000 DOI: 10.1093/nar/gkw752] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/20/2016] [Indexed: 12/14/2022] Open
Abstract
Dietary calorie restriction is a broadly acting intervention that extends the lifespan of various organisms from yeast to mammals. On another front, magnesium (Mg2+) is an essential biological metal critical to fundamental cellular processes and is commonly used as both a dietary supplement and treatment for some clinical conditions. If connections exist between calorie restriction and Mg2+ is unknown. Here, we show that Mg2+, acting alone or in response to dietary calorie restriction, allows eukaryotic cells to combat genome-destabilizing and lifespan-shortening accumulations of RNA–DNA hybrids, or R-loops. In an R-loop accumulation model of Pbp1-deficient Saccharomyces cerevisiae, magnesium ions guided by cell membrane Mg2+ transporters Alr1/2 act via Mg2+-sensitive R-loop suppressors Rnh1/201 and Pif1 to restore R-loop suppression, ribosomal DNA stability and cellular lifespan. Similarly, human cells deficient in ATXN2, the human ortholog of Pbp1, exhibit nuclear R-loop accumulations repressible by Mg2+ in a process that is dependent on the TRPM7 Mg2+ transporter and the RNaseH1 R-loop suppressor. Thus, we identify Mg2+ as a biochemical signal of beneficial calorie restriction, reveal an R-loop suppressing function for human ATXN2 and propose that practical magnesium supplementation regimens can be used to combat R-loop accumulation linked to the dysfunction of disease-linked human genes.
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Affiliation(s)
- Karan J Abraham
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Janet N Y Chan
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Jayesh S Salvi
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Brandon Ho
- Department of Biochemistry and Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Amanda Hall
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Elva Vidya
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Ru Guo
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Samuel A Killackey
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Nancy Liu
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Jeffrey E Lee
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada Canada Research Chairs Program, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Grant W Brown
- Department of Biochemistry and Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada Canada Research Chairs Program, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
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31
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Svenkrtova A, Belicova L, Volejnikova A, Sigler K, Jazwinski SM, Pichova A. Stratification of yeast cells during chronological aging by size points to the role of trehalose in cell vitality. Biogerontology 2016; 17:395-408. [PMID: 26614086 PMCID: PMC4808460 DOI: 10.1007/s10522-015-9625-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/23/2015] [Indexed: 02/06/2023]
Abstract
Cells of the budding yeast Saccharomyces cerevisiae undergo a process akin to differentiation during prolonged culture without medium replenishment. Various methods have been used to separate and determine the potential role and fate of the different cell species. We have stratified chronologically-aged yeast cultures into cells of different sizes, using centrifugal elutriation, and characterized these subpopulations physiologically. We distinguish two extreme cell types, very small (XS) and very large (L) cells. L cells display higher viability based on two separate criteria. They respire much more actively, but produce lower levels of reactive oxygen species (ROS). L cells are capable of dividing, albeit slowly, giving rise to XS cells which do not divide. L cells are more resistant to osmotic stress and they have higher trehalose content, a storage carbohydrate often connected to stress resistance. Depletion of trehalose by deletion of TPS2 does not affect the vital characteristics of L cells, but it improves some of these characteristics in XS cells. Therefore, we propose that the response of L and XS cells to the trehalose produced in the former differs in a way that lowers the vitality of the latter. We compare our XS- and L-fraction cell characteristics with those of cells isolated from stationary cultures by others based on density. This comparison suggests that the cells have some similarities but also differences that may prove useful in addressing whether it is the segregation or the response to trehalose that may play the predominant role in cell division from stationary culture.
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32
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Which Is the Most Significant Cause of Aging? Antioxidants (Basel) 2015; 4:793-810. [PMID: 26783959 PMCID: PMC4712935 DOI: 10.3390/antiox4040793] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/19/2015] [Accepted: 12/02/2015] [Indexed: 12/19/2022] Open
Abstract
It becomes clearer and clearer that aging is a result of a significant number of causes and it would seem that counteracting one or several of them should not make a significant difference. Taken at face value, this suggests, for example, that free radicals and reactive oxygen species do not play a significant role in aging and that the lifespan of organisms cannot be significantly extended. In this review, I point to the fact that the causes of aging synergize with each other and discuss the implications involved. One implication is that when two or more synergizing causes increase over time, the result of their action increases dramatically; I discuss a simple model demonstrating this. It is reasonable to conclude that this might explain the acceleration of aging and mortality with age. In this regard, the analysis of results and mortality patterns described in studies involving yeasts and Drosophila provides support for this view. Since the causes of aging are synergizing, it is also concluded that none of them is the major one but many including free radicals, etc. play significant roles. It follows that health/lifespan might be significantly extended if we eliminate or even attenuate the increase of a few or even just one of the causes of aging. While the synergism between the causes of aging is the main topic of this review, several related matters are briefly discussed as well.
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33
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Saarikangas J, Barral Y. Protein aggregates are associated with replicative aging without compromising protein quality control. eLife 2015; 4. [PMID: 26544680 PMCID: PMC4635334 DOI: 10.7554/elife.06197] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 10/19/2015] [Indexed: 12/12/2022] Open
Abstract
Differentiation of cellular lineages is facilitated by asymmetric segregation of fate determinants between dividing cells. In budding yeast, various aging factors segregate to the aging (mother)-lineage, with poorly understood consequences. In this study, we show that yeast mother cells form a protein aggregate during early replicative aging that is maintained as a single, asymmetrically inherited deposit over the remaining lifespan. Surprisingly, deposit formation was not associated with stress or general decline in proteostasis. Rather, the deposit-containing cells displayed enhanced degradation of cytosolic proteasome substrates and unimpaired clearance of stress-induced protein aggregates. Deposit formation was dependent on Hsp42, which collected non-random client proteins of the Hsp104/Hsp70-refolding machinery, including the prion Sup35. Importantly, loss of Hsp42 resulted in symmetric inheritance of its constituents and prolonged the lifespan of the mother cell. Together, these data suggest that protein aggregation is an early aging-associated differentiation event in yeast, having a two-faceted role in organismal fitness. DOI:http://dx.doi.org/10.7554/eLife.06197.001 Aging is a complex process. Studies involving a single-celled organism called budding yeast are commonly used to investigate the factors that contribute to aging. When these yeast cells divide, a small daughter cell buds out from a large mother cell. A mother cell has a limited lifespan and produces a finite number of daughter cells and then dies (a phenomenon referred to ‘replicative aging’). However, when a daughter cell forms, the daughter's age is reset to zero, giving it the full potential to produce new offspring. Previous research on budding yeast has shown that damaged or aggregated proteins accumulate in the mother cells but not the daughter cells, and that this accumulation of proteins contributes to shortening the lifespan of the mother cell. Furthermore, protein aggregation has also been associated with a number of age-related diseases in humans, including neurodegenerative disorders such as Alzheimer's and Parkinson's disease. However, it remains unclear how cells respond to protein aggregation that occurs during aging. Many studies that have previously investigated this question have relied on exposing cells to stressful conditions, such as high temperatures, in order to trigger proteins to aggregate. But now, Saarikangas and Barral have studied how proteins aggregate under normal, unstressed conditions in budding yeast as they age. The experiments revealed that most unstressed yeast cells develop a single deposit of aggregated proteins already during early aging. This age-associated structure proved to be a different type of response than the protein aggregation that occurs during stress. Furthermore, the deposit did not form as a consequence of the cell having obvious problems with folding its proteins, nor did the deposit hinder cells from coping with stressful conditions that trigger protein misfolding. Rather, this deposit supported the ability of the cell to degrade defective proteins. This suggests that the deposit represents an early adaptive response to aging, which might consequently provide aged cells some advantage over their younger counterparts. Saarikangas and Barral also found that this protein deposit was always retained in the mother cell and not passed onto the daughters at cell division. Further experiments showed that an enzyme called heat shock protein 42 was responsible for collecting target proteins and bring them together to form the single deposit. Reducing the levels of this enzyme prevented the deposit from forming and extended the lifespan of the mother cells. Thus, these findings suggest that mother cells collect harmful protein aggregates into a single deposit and prevent them from entering the daughter cells. Further work is needed to understand how the deposit is preferentially retained within the mother cell. DOI:http://dx.doi.org/10.7554/eLife.06197.002
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Affiliation(s)
- Juha Saarikangas
- Institute of Biochemistry, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Yves Barral
- Institute of Biochemistry, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
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34
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Molon M, Zadrag-Tecza R. Effect of temperature on replicative aging of the budding yeast Saccharomyces cerevisiae. Biogerontology 2015; 17:347-57. [PMID: 26481919 DOI: 10.1007/s10522-015-9619-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 10/09/2015] [Indexed: 11/28/2022]
Abstract
The use of the budding yeast Saccharomyces cerevisiae in gerontological studies was based on the assumption that the reproduction limit of a single cell (replicative aging) is a consequence of accumulation of a hypothetical universal "senescence factor" within the mother cell. However, some evidence suggests that molecules or structures proposed as the "aging factor", such as rDNA circles, oxidatively damaged proteins (with carbonyl groups) or mitochondria, have little effect on replicative lifespan of yeast cells. Our results also suggest that protein aggregates associated with Hsp104, treated as a marker of yeast aging, do not seem to affect the numeric value of replicative lifespan of yeast. What these results indicate, however, is the need for finding a different way of expressing age and longevity of yeast cells instead of the commonly used number of daughters produced over units of time, as in the case of other organisms. In this paper, we show that the temperature has a stronger influence on the time of life (the total lifespan) than on the reproductive potential of yeast cells.
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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
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35
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Moore D, Pilz G, Araúzo-Bravo M, Barral Y, Jessberger S. A mechanism for the segregation of age in mammalian neural stem cells. Science 2015; 349:1334-8. [PMID: 26383951 DOI: 10.1126/science.aac9868] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Throughout life, neural stem cells (NSCs) generate neurons in the mammalian brain. Using photobleaching experiments, we found that during cell division in vitro and within the developing mouse forebrain, NSCs generate a lateral diffusion barrier in the membrane of the endoplasmic reticulum, thereby promoting asymmetric segregation of cellular components. The diffusion barrier weakens with age and in response to impairment of lamin-associated nuclear envelope constituents. Weakening of the diffusion barrier disrupts asymmetric segregation of damaged proteins, a product of aging. Damaged proteins are asymmetrically inherited by the nonstem daughter cell in embryonic and young adult NSC divisions, whereas in the older adult brain, damaged proteins are more symmetrically distributed between progeny. Thus, these data identify a mechanism of how damage that accumulates with age is asymmetrically distributed during somatic stem cell division.
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Affiliation(s)
- Darcie Moore
- Brain Research Institute, Faculty of Medicine and Science, University of Zürich, 8057 Zürich, Switzerland
| | - Gregor Pilz
- Brain Research Institute, Faculty of Medicine and Science, University of Zürich, 8057 Zürich, Switzerland
| | - Marcos Araúzo-Bravo
- Biodonostia Health Research Institute, 20014 San Sebastián, Spain. IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Yves Barral
- Institute of Biochemistry, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Sebastian Jessberger
- Brain Research Institute, Faculty of Medicine and Science, University of Zürich, 8057 Zürich, Switzerland.
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36
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Piña FJ, Niwa M. The ER Stress Surveillance (ERSU) pathway regulates daughter cell ER protein aggregate inheritance. eLife 2015; 4. [PMID: 26327697 PMCID: PMC4555637 DOI: 10.7554/elife.06970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 08/04/2015] [Indexed: 12/11/2022] Open
Abstract
Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the daughter cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother cell to protect the functional capacity of daughter cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the cell cycle.
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Affiliation(s)
- Francisco J Piña
- Division of Biological Sciences, Section of Molecular Biology, Univeristy of California, San Diego, San Diego, United States
| | - Maho Niwa
- Division of Biological Sciences, Section of Molecular Biology, Univeristy of California, San Diego, San Diego, United States
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37
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Arlia-Ciommo A, Piano A, Leonov A, Svistkova V, Titorenko VI. Quasi-programmed aging of budding yeast: a trade-off between programmed processes of cell proliferation, differentiation, stress response, survival and death defines yeast lifespan. Cell Cycle 2015; 13:3336-49. [PMID: 25485579 PMCID: PMC4614525 DOI: 10.4161/15384101.2014.965063] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent findings suggest that evolutionarily distant organisms share the key features of the aging process and exhibit similar mechanisms of its modulation by certain genetic, dietary and pharmacological interventions. The scope of this review is to analyze mechanisms that in the yeast Saccharomyces cerevisiae underlie: (1) the replicative and chronological modes of aging; (2) the convergence of these 2 modes of aging into a single aging process; (3) a programmed differentiation of aging cell communities in liquid media and on solid surfaces; and (4) longevity-defining responses of cells to some chemical compounds released to an ecosystem by other organisms populating it. Based on such analysis, we conclude that all these mechanisms are programs for upholding the long-term survival of the entire yeast population inhabiting an ecological niche; however, none of these mechanisms is a ʺprogram of agingʺ - i.e., a program for progressing through consecutive steps of the aging process.
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Key Words
- D, diauxic growth phase
- ERCs, extrachromosomal rDNA circles
- IPOD, insoluble protein deposit
- JUNQ, juxtanuclear quality control compartment
- L, logarithmic growth phase
- MBS, the mitochondrial back-signaling pathway
- MTC, the mitochondrial translation control signaling pathway
- NPCs, nuclear pore complexes
- NQ, non-quiescent cells
- PD, post-diauxic growth phase
- Q, quiescent cells
- ROS, reactive oxygen species
- RTG, the mitochondrial retrograde signaling pathway
- Ras/cAMP/PKA, the Ras family GTPase/cAMP/protein kinase A signaling pathway
- ST, stationary growth phase
- TOR/Sch9, the target of rapamycin/serine-threonine protein kinase Sch9 signaling pathway
- UPRER, the unfolded protein response pathway in the endoplasmic reticulum
- UPRmt, the unfolded protein response pathway in mitochondria
- cell growth and proliferation
- cell survival
- cellular aging
- ecosystems
- evolution
- longevity
- programmed cell death
- yeast
- yeast colony
- yeast replicative and chronological aging
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38
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Kaya A, Lobanov AV, Gladyshev VN. Evidence that mutation accumulation does not cause aging in Saccharomyces cerevisiae. Aging Cell 2015; 14:366-71. [PMID: 25702753 PMCID: PMC4406665 DOI: 10.1111/acel.12290] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2014] [Indexed: 12/12/2022] Open
Abstract
The concept that mutations cause aging phenotypes could not be directly tested previously due to inability to identify age-related mutations in somatic cells and determine their impact on organismal aging. Here, we subjected Saccharomyces cerevisiae to multiple rounds of replicative aging and assessed de novo mutations in daughters of mothers of different age. Mutations did increase with age, but their low numbers, < 1 per lifespan, excluded their causal role in aging. Structural genome changes also had no role. A mutant lacking thiol peroxidases had the mutation rate well above that of wild-type cells, but this did not correspond to the aging pattern, as old wild-type cells with few or no mutations were dying, whereas young mutant cells with many more mutations continued dividing. In addition, wild-type cells lost mitochondrial DNA during aging, whereas shorter-lived mutant cells preserved it, excluding a causal role of mitochondrial mutations in aging. Thus, DNA mutations do not cause aging in yeast. These findings may apply to other damage types, suggesting a causal role of cumulative damage, as opposed to individual damage types, in organismal aging.
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Affiliation(s)
- Alaattin Kaya
- Division of Genetics Department of Medicine Brigham and Women's Hospital and Harvard Medical School Boston MA 02115 USA
| | - Alexei V. Lobanov
- Division of Genetics Department of Medicine Brigham and Women's Hospital and Harvard Medical School Boston MA 02115 USA
| | - Vadim N. Gladyshev
- Division of Genetics Department of Medicine Brigham and Women's Hospital and Harvard Medical School Boston MA 02115 USA
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39
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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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40
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van Deventer S, Menendez-Benito V, van Leeuwen F, Neefjes J. N-terminal acetylation and replicative age affect proteasome localization and cell fitness during aging. J Cell Sci 2015; 128:109-17. [PMID: 25413350 PMCID: PMC4282048 DOI: 10.1242/jcs.157354] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 11/05/2014] [Indexed: 01/05/2023] Open
Abstract
Specific degradation of proteins is essential for virtually all cellular processes and is carried out predominantly by the proteasome. The proteasome is important for clearance of damaged cellular proteins. Damaged proteins accumulate over time and excess damaged proteins can aggregate and induce the death of old cells. In yeast, the localization of the proteasome changes dramatically during aging, possibly in response to altered proteasome activity requirements. We followed two key parameters of this process: the distribution of proteasomes in nuclear and cytosolic compartments, and the formation of cytoplasmic aggregate-like structures called proteasome storage granules (PSGs). Whereas replicative young cells efficiently relocalized proteasomes from the nucleus to the cytoplasm and formed PSGs, replicative old cells were less efficient in relocalizing the proteasome and had less PSGs. By using a microscopy-based genome-wide screen, we identified genetic factors involved in these processes. Both relocalization of the proteasome and PSG formation were affected by two of the three N-acetylation complexes. These N-acetylation complexes also had different effects on the longevity of cells, indicating that each N-acetylation complex has different roles in proteasome location and aging.
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Affiliation(s)
- Sjoerd van Deventer
- Division of Cell Biology, Netherlands Cancer Institute and Netherlands Proteomics Center, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Victoria Menendez-Benito
- Division of Cell Biology, Netherlands Cancer Institute and Netherlands Proteomics Center, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute and Netherlands Proteomics Center, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Jacques Neefjes
- Division of Cell Biology, Netherlands Cancer Institute and Netherlands Proteomics Center, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
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Spivey EC, Xhemalce B, Shear JB, Finkelstein IJ. 3D-printed microfluidic microdissector for high-throughput studies of cellular aging. Anal Chem 2014; 86:7406-12. [PMID: 24992972 PMCID: PMC4636036 DOI: 10.1021/ac500893a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to their short lifespan, rapid division, and ease of genetic manipulation, yeasts are popular model organisms for studying aging in actively dividing cells. To study replicative aging over many cell divisions, individual cells must be continuously separated from their progeny via a laborious manual microdissection procedure. Microfluidics-based soft-lithography devices have recently been used to automate microdissection of the budding yeast Saccharomyces cerevisiae. However, little is known about replicative aging in Schizosaccharomyces pombe, a rod-shaped yeast that divides by binary fission and shares many conserved biological functions with higher eukaryotes. In this report, we develop a versatile multiphoton lithography method that enables rapid fabrication of three-dimensional master structures for polydimethylsiloxane (PDMS)-based microfluidics. We exploit the rapid prototyping capabilities of multiphoton lithography to create and characterize a cell-capture device that is capable of high-resolution microscopic observation of hundreds of individual S. pombe cells. By continuously removing the progeny cells, we demonstrate that cell growth and protein aggregation can be tracked in individual cells for over ~100 h. Thus, the fission yeast lifespan microdissector (FYLM) provides a powerful on-chip microdissection platform that will enable high-throughput studies of aging in rod-shaped cells.
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Affiliation(s)
- Eric C. Spivey
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Blerta Xhemalce
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Jason B. Shear
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
| | - Ilya J. Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712
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Dynamic JUNQ inclusion bodies are asymmetrically inherited in mammalian cell lines through the asymmetric partitioning of vimentin. Proc Natl Acad Sci U S A 2014; 111:8049-54. [PMID: 24843142 DOI: 10.1073/pnas.1324035111] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Aging is associated with the accumulation of several types of damage: in particular, damage to the proteome. Recent work points to a conserved replicative rejuvenation mechanism that works by preventing the inheritance of damaged and misfolded proteins by specific cells during division. Asymmetric inheritance of misfolded and aggregated proteins has been shown in bacteria and yeast, but relatively little evidence exists for a similar mechanism in mammalian cells. Here, we demonstrate, using long-term 4D imaging, that the vimentin intermediate filament establishes mitotic polarity in mammalian cell lines and mediates the asymmetric partitioning of damaged proteins. We show that mammalian JUNQ inclusion bodies containing soluble misfolded proteins are inherited asymmetrically, similarly to JUNQ quality-control inclusions observed in yeast. Mammalian IPOD-like inclusion bodies, meanwhile, are not always inherited by the same cell as the JUNQ. Our study suggests that the mammalian cytoskeleton and intermediate filaments provide the physical scaffold for asymmetric inheritance of dynamic quality-control JUNQ inclusions. Mammalian IPOD inclusions containing amyloidogenic proteins are not partitioned as effectively during mitosis as their counterparts in yeast. These findings provide a valuable mechanistic basis for studying the process of asymmetric inheritance in mammalian cells, including cells potentially undergoing polar divisions, such as differentiating stem cells and cancer cells.
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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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Abstract
During cellular division, centrosomes are tasked with building the bipolar mitotic spindle, which partitions the cellular contents into two daughter cells. While every cell will receive an equal complement of chromosomes, not every organelle is symmetrically passaged to the two progeny in many cell types. In this review, we highlight the conservation of nonrandom centrosome segregation in asymmetrically dividing stem cells, and we discuss how the asymmetric function of centrosomes could mediate nonrandom segregation of organelles and mRNA. We propose that such a mechanism is critical for insuring proper cell fitness, function, and fate.
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Spivey EC, Finkelstein IJ. From cradle to grave: high-throughput studies of aging in model organisms. MOLECULAR BIOSYSTEMS 2014; 10:1658-67. [PMID: 24535099 DOI: 10.1039/c3mb70604d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aging-the progressive decline of biological functions-is a universal fact of life. Decades of intense research in unicellular and metazoan model organisms have highlighted that aging manifests at all levels of biological organization - from the decline of individual cells, to tissue and organism degeneration. To better understand the aging process, we must first aim to integrate quantitative biological understanding on the systems and cellular levels. A second key challenge is to then understand the many heterogeneous outcomes that may result in aging cells, and to connect cellular aging to organism-wide degeneration. Addressing these challenges requires the development of high-throughput aging and longevity assays. In this review, we highlight the emergence of high-throughput aging approaches in the most commonly used model organisms. We conclude with a discussion of the critical questions that can be addressed with these new methods.
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Affiliation(s)
- Eric C Spivey
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
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Ganley ARD, Kobayashi T. Ribosomal DNA and cellular senescence: new evidence supporting the connection between rDNA and aging. FEMS Yeast Res 2014; 14:49-59. [DOI: 10.1111/1567-1364.12133] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 12/10/2013] [Accepted: 12/19/2013] [Indexed: 12/19/2022] Open
Affiliation(s)
- Austen R. D. Ganley
- Institute of Natural and Mathematical Sciences; Massey University; Auckland New Zealand
| | - Takehiko Kobayashi
- Division of Cytogenetics; National Institute of Genetics; Mishima Shizuoka Japan
- Department of Genetics; The Graduate University for Advanced Studies; SOKENDAI; Mishima Shizuoka Japan
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Wasko BM, Kaeberlein M. Yeast replicative aging: a paradigm for defining conserved longevity interventions. FEMS Yeast Res 2013; 14:148-59. [PMID: 24119093 DOI: 10.1111/1567-1364.12104] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/22/2013] [Accepted: 09/26/2013] [Indexed: 12/15/2022] Open
Abstract
The finite replicative life span of budding yeast mother cells was demonstrated as early as 1959, but the idea that budding yeast could be used to model aging of multicellular eukaryotes did not enter the scientific mainstream until relatively recently. Despite continued skepticism by some, there are now abundant data that several interventions capable of extending yeast replicative life span have a similar effect in multicellular eukaryotes including nematode worms, fruit flies, and rodents. In particular, dietary restriction, mTOR signaling, and sirtuins are among the most studied longevity interventions in the field. Here, we describe key conserved longevity pathways in yeast and discuss relationships that may help explain how such broad conservation of aging processes could have evolved.
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Affiliation(s)
- Brian M Wasko
- Department of Pathology, University of Washington, Seattle, WA, USA
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Abstract
Asymmetric cell division (ACD), a mechanism for cell-type diversification in both prokaryotes and eukaryotes, is accomplished through highly coordinated cell-fate segregation, genome partitioning, and cell division. Whereas important paradigms have arisen from the study of animal embryonic divisions, the strategies for choreographing the dynamic subprocesses are, in fact, highly varied. This review examines divergent mechanisms of ACD across different kingdoms. Examples discussed show that there is no obligatory hierarchy among the dynamic events and that asymmetry can emerge from each event, but cell polarization more often occurs as the initial instructive process for patterning ACD especially in the multicellular context.
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Affiliation(s)
- Rong Li
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA.
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Roles of mitochondrial dynamics under stressful and normal conditions in yeast cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:139491. [PMID: 23956814 PMCID: PMC3728513 DOI: 10.1155/2013/139491] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/25/2013] [Indexed: 01/20/2023]
Abstract
Eukaryotic cells contain dynamic mitochondrial filaments: they fuse and divide. Here we summarize data on the protein machinery driving mitochondrial dynamics in yeast and also discuss the factors that affect the fusion-fission balance. Fission is a general stress response of cells, and in the case of yeast this response appears to be prosurvival. At the same time, even under normal conditions yeast mitochondria undergo continuous cycles of fusion and fission. This seems to be a futile cycle and also expensive from the energy point of view. Why does it exist? Benefits might be the same as in the case of sexual reproduction. Indeed, mixing and separating of mitochondrial content allows mitochondrial DNA to segregate and recombine randomly, leading to high variation in the numbers of mutations per individual mitochondrion. This opens a possibility for effective purifying selection-elimination of mitochondria highly contaminated by deleterious mutations. The beneficial action presumes a mechanism for removal of defective mitochondria. We argue that selective mitochondrial autophagy or asymmetrical distribution of mitochondria during cell division could be at the core of such mechanism.
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