1
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Hong S, Lee HG, Huh WK. ARV1 deficiency induces lipid bilayer stress and enhances rDNA stability by activating the unfolded protein response in Saccharomyces cerevisiae. J Biol Chem 2024; 300:107273. [PMID: 38588806 PMCID: PMC11089378 DOI: 10.1016/j.jbc.2024.107273] [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: 08/14/2023] [Revised: 03/18/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024] Open
Abstract
The stability of ribosomal DNA (rDNA) is maintained through transcriptional silencing by the NAD+-dependent histone deacetylase Sir2 in Saccharomyces cerevisiae. Alongside proteostasis, rDNA stability is a crucial factor regulating the replicative lifespan of S. cerevisiae. The unfolded protein response (UPR) is induced by misfolding of proteins or an imbalance of membrane lipid composition and is responsible for degrading misfolded proteins and restoring endoplasmic reticulum (ER) membrane homeostasis. Recent investigations have suggested that the UPR can extend the replicative lifespan of yeast by enhancing protein quality control mechanisms, but the relationship between the UPR and rDNA stability remains unknown. In this study, we found that the deletion of ARV1, which encodes an ER protein of unknown molecular function, activates the UPR by inducing lipid bilayer stress. In arv1Δ cells, the UPR and the cell wall integrity pathway are activated independently of each other, and the high osmolarity glycerol (HOG) pathway is activated in a manner dependent on Ire1, which mediates the UPR. Activated Hog1 translocates the stress response transcription factor Msn2 to the nucleus, where it promotes the expression of nicotinamidase Pnc1, a well-known Sir2 activator. Following Sir2 activation, rDNA silencing and rDNA stability are promoted. Furthermore, the loss of other ER proteins, such as Pmt1 or Bst1, and ER stress induced by tunicamycin or inositol depletion also enhance rDNA stability in a Hog1-dependent manner. Collectively, these findings suggest that the induction of the UPR enhances rDNA stability in S. cerevisiae by promoting the Msn2-Pnc1-Sir2 pathway in a Hog1-dependent manner.
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Affiliation(s)
- Sujin Hong
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyeon-Geun Lee
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea; Institute of Microbiology, Seoul National University, Seoul, Republic of Korea.
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2
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Paul PK, Umarvaish S, Bajaj S, S. RF, Mohan H, Annaert W, Chaudhary V. Maintenance of proteostasis by Drosophila Rer1 is essential for competitive cell survival and Myc-driven overgrowth. PLoS Genet 2024; 20:e1011171. [PMID: 38408084 PMCID: PMC10919865 DOI: 10.1371/journal.pgen.1011171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 03/07/2024] [Accepted: 02/05/2024] [Indexed: 02/28/2024] Open
Abstract
Defects in protein homeostasis can induce proteotoxic stress, affecting cellular fitness and, consequently, overall tissue health. In various growing tissues, cell competition based mechanisms facilitate detection and elimination of these compromised, often referred to as 'loser', cells by the healthier neighbors. The precise connection between proteotoxic stress and competitive cell survival remains largely elusive. Here, we reveal the function of an endoplasmic reticulum (ER) and Golgi localized protein Rer1 in the regulation of protein homeostasis in the developing Drosophila wing epithelium. Our results show that loss of Rer1 leads to proteotoxic stress and PERK-mediated phosphorylation of eukaryotic initiation factor 2α. Clonal analysis showed that rer1 mutant cells are identified as losers and eliminated through cell competition. Interestingly, we find that Rer1 levels are upregulated upon Myc-overexpression that causes overgrowth, albeit under high proteotoxic stress. Our results suggest that increased levels of Rer1 provide cytoprotection to Myc-overexpressing cells by alleviating the proteotoxic stress and thereby supporting Myc-driven overgrowth. In summary, these observations demonstrate that Rer1 acts as a novel regulator of proteostasis in Drosophila and reveal its role in competitive cell survival.
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Affiliation(s)
- Pranab Kumar Paul
- Cell and developmental signaling laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
| | - Shruti Umarvaish
- Cell and developmental signaling laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
| | - Shivani Bajaj
- Cell and developmental signaling laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
| | - Rishana Farin S.
- Cell and developmental signaling laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
| | - Hrudya Mohan
- Cell and developmental signaling laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, Leuven, Belgium, and Department of Neurosciences, KU Leuven, Gasthuisberg, Leuven, Belgium
| | - Varun Chaudhary
- Cell and developmental signaling laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
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3
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Ölmez TT, Moreno DF, Liu P, Johnson ZM, McGinnis MM, Tu BP, Hochstrasser M, Acar M. Sis2 regulates yeast replicative lifespan in a dose-dependent manner. Nat Commun 2023; 14:7719. [PMID: 38012152 PMCID: PMC10682402 DOI: 10.1038/s41467-023-43233-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/01/2023] [Indexed: 11/29/2023] Open
Abstract
Application of microfluidic platforms facilitated high-precision measurements of yeast replicative lifespan (RLS); however, comparative quantification of lifespan across strain libraries has been missing. Here we microfluidically measure the RLS of 307 yeast strains, each deleted for a single gene. Despite previous reports of extended lifespan in these strains, we found that 56% of them did not actually live longer than the wild-type; while the remaining 44% showed extended lifespans, the degree of extension was often different from what was previously reported. Deletion of SIS2 gene led to the largest RLS increase observed. Sis2 regulated yeast lifespan in a dose-dependent manner, implying a role for the coenzyme A biosynthesis pathway in lifespan regulation. Introduction of the human PPCDC gene in the sis2Δ background neutralized the lifespan extension. RNA-seq experiments revealed transcriptional increases in cell-cycle machinery components in sis2Δ background. High-precision lifespan measurement will be essential to elucidate the gene network governing lifespan.
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Affiliation(s)
- Tolga T Ölmez
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
- Koç University Research Center for Translational Medicine, Koç University, Rumelifeneri Yolu, Sarıyer, İstanbul, 34450, Turkey
- Department of Basic Medical Sciences, Koc University Rumelifeneri Yolu, Sarıyer, İstanbul, 34450, Turkey
| | - David F Moreno
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch-Graffenstaden, 67400, France
| | - Ping Liu
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - Zane M Johnson
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT, 06520, USA
| | - Madeline M McGinnis
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Benjamin P Tu
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Mark Hochstrasser
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT, 06520, USA
| | - Murat Acar
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA.
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA.
- Department of Basic Medical Sciences, Koc University Rumelifeneri Yolu, Sarıyer, İstanbul, 34450, Turkey.
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4
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Lara-Barba E, Torán-Vilarrubias A, Moriel-Carretero M. An Expansion of the Endoplasmic Reticulum that Halts Autophagy is Permissive to Genome Instability. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231157706. [PMID: 37366415 PMCID: PMC10243512 DOI: 10.1177/25152564231157706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/27/2023] [Accepted: 01/27/2023] [Indexed: 06/28/2023]
Abstract
The links between autophagy and genome stability, and whether they are important for lifespan and health, are not fully understood. We undertook a study to explore this notion at the molecular level using Saccharomyces cerevisiae. On the one hand, we triggered autophagy using rapamycin, to which we exposed mutants defective in preserving genome integrity, then assessed their viability, their ability to induce autophagy and the link between these two parameters. On the other hand, we searched for molecules derived from plant extracts known to have powerful benefits on human health to try to rescue the negative effects rapamycin had against some of these mutants. We uncover that autophagy execution is lethal for mutants unable to repair DNA double strand breaks, while the extract from Silybum marianum seeds induces an expansion of the endoplasmic reticulum (ER) that blocks autophagy and protects them. Our data uncover a connection between genome integrity and homeostasis of the ER whereby ER stress-like scenarios render cells tolerant to sub-optimal genome integrity conditions.
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Affiliation(s)
- Eliana Lara-Barba
- Institut de Génétique Humaine (IGH), Université de Montpellier-Centre National de la Recherche Scientifique,
Montpellier, France
| | - Alba Torán-Vilarrubias
- Institut de Génétique Humaine (IGH), Université de Montpellier-Centre National de la Recherche Scientifique,
Montpellier, France
| | - María Moriel-Carretero
- Centre de Recherche en Biologie cellulaire de
Montpellier (CRBM), Université de Montpellier-Centre National de la Recherche Scientifique,
Montpellier, France
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5
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Cai Q, Ganesan D. Regulation of neuronal autophagy and the implications in neurodegenerative diseases. Neurobiol Dis 2022; 162:105582. [PMID: 34890791 PMCID: PMC8764935 DOI: 10.1016/j.nbd.2021.105582] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/22/2021] [Accepted: 12/06/2021] [Indexed: 01/03/2023] Open
Abstract
Neurons are highly polarized and post-mitotic cells with the specific requirements of neurotransmission accompanied by high metabolic demands that create a unique challenge for the maintenance of cellular homeostasis. Thus, neurons rely heavily on autophagy that constitutes a key quality control system by which dysfunctional cytoplasmic components, protein aggregates, and damaged organelles are sequestered within autophagosomes and then delivered to the lysosome for degradation. While mature lysosomes are predominantly located in the soma of neurons, the robust, constitutive biogenesis of autophagosomes occurs in the synaptic terminal via a conserved pathway that is required to maintain synaptic integrity and function. Following formation, autophagosomes fuse with late endosomes and then are rapidly and efficiently transported by the microtubule-based cytoplasmic dynein motor along the axon toward the soma for lysosomal clearance. In this review, we highlight the recent knowledge of the roles of autophagy in neuronal health and disease. We summarize the available evidence about the normal functions of autophagy as a protective factor against neurodegeneration and discuss the mechanism underlying neuronal autophagy regulation. Finally, we describe how autophagy function is affected in major neurodegenerative diseases with a special focus on Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis.
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6
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Ray B, Mahalakshmi AM, Tuladhar S, Bhat A, Srinivasan A, Pellegrino C, Kannan A, Bolla SR, Chidambaram SB, Sakharkar MK. "Janus-Faced" α-Synuclein: Role in Parkinson's Disease. Front Cell Dev Biol 2021; 9:673395. [PMID: 34124057 PMCID: PMC8194081 DOI: 10.3389/fcell.2021.673395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/15/2021] [Indexed: 01/03/2023] Open
Abstract
Parkinson's disease (PD) is a pathological condition characterized by the aggregation and the resultant presence of intraneuronal inclusions termed Lewy bodies (LBs) and Lewy neurites which are mainly composed of fibrillar α-synuclein (α-syn) protein. Pathogenic aggregation of α-syn is identified as the major cause of LBs deposition. Several mutations in α-syn showing varied aggregation kinetics in comparison to the wild type (WT) α-syn are reported in PD (A30P, E46K, H 50Q, G51D, A53E, and A53T). Also, the cell-to-cell spread of pathological α-syn plays a significant role in PD development. Interestingly, it has also been suggested that the pathology of PD may begin in the gastrointestinal tract and spread via the vagus nerve (VN) to brain proposing the gut-brain axis of α-syn pathology in PD. Despite multiple efforts, the behavior and functions of this protein in normal and pathological states (specifically in PD) is far from understood. Furthermore, the etiological factors responsible for triggering aggregation of this protein remain elusive. This review is an attempt to collate and present latest information on α-syn in relation to its structure, biochemistry and biophysics of aggregation in PD. Current advances in therapeutic efforts toward clearing the pathogenic α-syn via autophagy/lysosomal flux are also reviewed and reported.
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Affiliation(s)
- Bipul Ray
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, India
- Centre for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education & Research, Mysuru, India
| | - Arehally M. Mahalakshmi
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, India
| | - Sunanda Tuladhar
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, India
- Centre for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education & Research, Mysuru, India
| | - Abid Bhat
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, India
- Centre for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education & Research, Mysuru, India
| | - Asha Srinivasan
- Division of Nanoscience & Technology, Faculty of Life Sciences, JSS Academy of Higher Education & Research, Mysuru, India
| | - Christophe Pellegrino
- Institut National de la Santé et de la Recherche Médicale, Institute of Mediterranean Neurobiology, Aix-Marseille University, Marseille, France
| | - Anbarasu Kannan
- Department of Protein Chemistry and Technology, CSIR-Central Food Technological Research Institute, Mysuru, India
| | - Srinivasa Rao Bolla
- Department of Biomedical Sciences, School of Medicine, Nazarbayev University, Nur-Sultan City, Kazakhstan
| | - Saravana Babu Chidambaram
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, India
- Centre for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education & Research, Mysuru, India
- Special Interest Group – Brain, Behaviour, and Cognitive Neurosciences Research, JSS Academy of Higher Education & Research, Mysuru, India
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7
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Lee SK. Endoplasmic Reticulum Homeostasis and Stress Responses in Caenorhabditis elegans. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:279-303. [PMID: 34050871 DOI: 10.1007/978-3-030-67696-4_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The unfolded protein response (UPR) is an evolutionarily conserved adaptive regulatory pathway that alleviates protein-folding defects in the endoplasmic reticulum (ER). Physiological demands, environmental perturbations and pathological conditions can cause accumulation of unfolded proteins in the ER and the stress signal is transmitted to the nucleus to turn on a series of genes to respond the challenge. In metazoan, the UPR pathways consisted of IRE1/XBP1, PEK-1 and ATF6, which function in parallel and downstream transcriptional activation triggers the proteostasis networks consisting of molecular chaperones, protein degradation machinery and other stress response pathways ((Labbadia J, Morimoto RI, F1000Prime Rep 6:7, 2014); (Shen X, Ellis RE, Lee K, Annu Rev Biochem 28:893-903, 2014)). The integrated responses act on to resolve the ER stress by increasing protein folding capacity, attenuating ER-loading translation, activating ER-associated proteasomal degradation (ERAD), and regulating IRE1-dependent decay of mRNA (RIDD). Therefore, the effective UPR to internal and external causes is linked to the multiple pathophysiological conditions such as aging, immunity, and neurodegenerative diseases. Recent development in the research of the UPR includes cell-nonautonomous features of the UPR, interplay between the UPR and other stress response pathways, unconventional UPR inducers, and noncanonical UPR independent of the three major branches, originated from multiple cellular and molecular machineries in addition to ER. Caenorhabditis elegans model system has critically contributed to these unprecedented aspects of the ER UPR and broadens the possible therapeutic targets to treat the ER-stress associated human disorders and time-dependent physiological deterioration of aging.
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Affiliation(s)
- Sun-Kyung Lee
- Department of Life Science, Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea.
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8
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Annaert W, Kaether C. Bring it back, bring it back, don't take it away from me - the sorting receptor RER1. J Cell Sci 2020; 133:133/17/jcs231423. [PMID: 32873699 DOI: 10.1242/jcs.231423] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The quote "bring it back, bring it back, don't take it away from me" from Queen's Love of my life describes the function of the sorting receptor RER1, a 23 kDa protein with four transmembrane domains (TMDs) that localizes to the intermediate compartment and the cis-Golgi. From there it returns escaped proteins that are not supposed to leave the endoplasmic reticulum (ER) back to it. Unique about RER1 is its ability to recognize its ligands through binding motifs in TMDs. Among its substrates are ER-resident proteins, as well as unassembled subunits of multimeric complexes that are retrieved back into the ER, this way guarding the full assembly of their respective complexes. The basic mechanisms for RER1-dependent retrieval have been already elucidated some years ago in yeast. More recently, several important cargoes of RER1 have been described in mammalian cells, and the in vivo role of RER1 is being unveiled by using mouse models. In this Review, we give an overview of the cell biology of RER1 in different models, discuss its controversial role in the brain and provide an outlook on future directions for RER1 research.
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Affiliation(s)
- Wim Annaert
- VIB Center for Brain and Disease Research & KU Leuven, Department of Neurosciences, Gasthuisberg, B-3000 Leuven, Belgium
| | - Christoph Kaether
- Leibniz Institut für Alternsforschung-Fritz Lipmann Institut, 07745 Jena, Germany
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9
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Sun Z, Brodsky JL. Protein quality control in the secretory pathway. J Cell Biol 2019; 218:3171-3187. [PMID: 31537714 PMCID: PMC6781448 DOI: 10.1083/jcb.201906047] [Citation(s) in RCA: 225] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/22/2019] [Accepted: 08/29/2019] [Indexed: 12/23/2022] Open
Abstract
Protein folding is inherently error prone, especially in the endoplasmic reticulum (ER). Even with an elaborate network of molecular chaperones and protein folding facilitators, misfolding can occur quite frequently. To maintain protein homeostasis, eukaryotes have evolved a series of protein quality-control checkpoints. When secretory pathway quality-control pathways fail, stress response pathways, such as the unfolded protein response (UPR), are induced. In addition, the ER, which is the initial hub of protein biogenesis in the secretory pathway, triages misfolded proteins by delivering substrates to the proteasome or to the lysosome/vacuole through ER-associated degradation (ERAD) or ER-phagy. Some misfolded proteins escape the ER and are instead selected for Golgi quality control. These substrates are targeted for degradation after retrieval to the ER or delivery to the lysosome/vacuole. Here, we discuss how these guardian pathways function, how their activities intersect upon induction of the UPR, and how decisions are made to dispose of misfolded proteins in the secretory pathway.
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Affiliation(s)
- Zhihao Sun
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
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10
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Cell organelles and yeast longevity: an intertwined regulation. Curr Genet 2019; 66:15-41. [PMID: 31535186 DOI: 10.1007/s00294-019-01035-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 12/16/2022]
Abstract
Organelles are dynamic structures of a eukaryotic cell that compartmentalize various essential functions and regulate optimum functioning. On the other hand, ageing is an inevitable phenomenon that leads to irreversible cellular damage and affects optimum functioning of cells. Recent research shows compelling evidence that connects organelle dysfunction to ageing-related diseases/disorders. Studies in several model systems including yeast have led to seminal contributions to the field of ageing in uncovering novel pathways, proteins and their functions, identification of pro- and anti-ageing factors and so on. In this review, we present a comprehensive overview of findings that highlight the role of organelles in ageing and ageing-associated functions/pathways in yeast.
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11
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Chadwick SR, Fazio EN, Etedali-Zadeh P, Genereaux J, Duennwald ML, Lajoie P. A functional unfolded protein response is required for chronological aging in Saccharomyces cerevisiae. Curr Genet 2019; 66:263-277. [PMID: 31346745 DOI: 10.1007/s00294-019-01019-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/08/2019] [Accepted: 07/16/2019] [Indexed: 12/29/2022]
Abstract
Progressive impairment of proteostasis and accumulation of toxic misfolded proteins are associated with the cellular aging process. Here, we employed chronologically aged yeast cells to investigate how activation of the unfolded protein response (UPR) upon accumulation of misfolded proteins in the endoplasmic reticulum (ER) affects lifespan. We found that cells lacking a functional UPR display a significantly reduced chronological lifespan, which contrasts previous findings in models of replicative aging. We find exacerbated UPR activation in aged cells, indicating an increase in misfolded protein burden in the ER during the course of aging. We also observed that caloric restriction, which promotes longevity in various model organisms, extends lifespan of UPR-deficient strains. Similarly, aging in pH-buffered media extends lifespan, albeit independently of the UPR. Thus, our data support a role for caloric restriction and reduced acid stress in improving ER homeostasis during aging. Finally, we show that UPR-mediated upregulation of the ER chaperone Kar2 and functional ER-associated degradation (ERAD) are essential for proper aging. Our work documents the central role of secretory protein homeostasis in chronological aging in yeast and highlights that the requirement for a functional UPR can differ between post-mitotic and actively dividing eukaryotic cells.
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Affiliation(s)
- Sarah R Chadwick
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, N6A 5C1, Canada
| | - Elena N Fazio
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, N6A 5C1, Canada
| | - Parnian Etedali-Zadeh
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, N6A 5C1, Canada
| | - Julie Genereaux
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, N6A 5C1, Canada.,Department of Biochemistry, The University of Western Ontario, London, N6A 5C1, Canada
| | - Martin L Duennwald
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, N6A 5C1, Canada.,Department of Pathology and Laboratory Medicine, The University of Western Ontario, London, N6A 5C1, Canada
| | - Patrick Lajoie
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, N6A 5C1, Canada.
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12
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Is Gcn4-induced autophagy the ultimate downstream mechanism by which hormesis extends yeast replicative lifespan? Curr Genet 2019; 65:717-720. [PMID: 30673825 DOI: 10.1007/s00294-019-00936-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/08/2019] [Accepted: 01/11/2019] [Indexed: 12/22/2022]
Abstract
The number of times a cell divides before irreversibly arresting is termed replicative lifespan. Despite discovery of many chemical, dietary and genetic interventions that extend replicative lifespan, usually first discovered in budding yeast and subsequently shown to apply to metazoans, there is still little understanding of the underlying molecular mechanisms involved. One unifying theme is that most, if not all, interventions that extend replicative lifespan induce "hormesis", where a little inflicted damage makes cells more able to resist similar challenges in the future. One of the many cellular changes that occur during hormesis is a global reduction in protein synthesis, which has been linked to enhanced longevity in many organisms. Our recent study in budding yeast found that it was not the reduction in protein synthesis per se, but rather the subsequent induction of the conserved Gcn4 transcriptional regulator and its ability to induce autophagy that was responsible for extending replicative lifespan. We propose that Gcn4-dependent induction of autophagy occurring downstream of reduced global protein synthesis may be a unifying molecular mechanism for many interventions that extend replicative lifespan.
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13
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Yeast at the Forefront of Research on Ageing and Age-Related Diseases. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2019; 58:217-242. [PMID: 30911895 DOI: 10.1007/978-3-030-13035-0_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ageing is a complex and multifactorial process driven by genetic, environmental and stochastic factors that lead to the progressive decline of biological systems. Mechanisms of ageing have been extensively investigated in various model organisms and systems generating fundamental advances. Notably, studies on yeast ageing models have made numerous and relevant contributions to the progress in the field. Different longevity factors and pathways identified in yeast have then been shown to regulate molecular ageing in invertebrate and mammalian models. Currently the best candidates for anti-ageing drugs such as spermidine and resveratrol or anti-ageing interventions such as caloric restriction were first identified and explored in yeast. Yeasts have also been instrumental as models to study the cellular and molecular effects of proteins associated with age-related diseases such as Parkinson's, Huntington's or Alzheimer's diseases. In this chapter, a review of the advances on ageing and age-related diseases research in yeast models will be made. Particular focus will be placed on key longevity factors, ageing hallmarks and interventions that slow ageing, both yeast-specific and those that seem to be conserved in multicellular organisms. Their impact on the pathogenesis of age-related diseases will be also discussed.
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14
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Hu Z, Xia B, Postnikoff SD, Shen ZJ, Tomoiaga AS, Harkness TA, Seol JH, Li W, Chen K, Tyler JK. Ssd1 and Gcn2 suppress global translation efficiency in replicatively aged yeast while their activation extends lifespan. eLife 2018; 7:35551. [PMID: 30117416 PMCID: PMC6097839 DOI: 10.7554/elife.35551] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/03/2018] [Indexed: 12/21/2022] Open
Abstract
Translational efficiency correlates with longevity, yet its role in lifespan determination remains unclear. Using ribosome profiling, translation efficiency is globally reduced during replicative aging in budding yeast by at least two mechanisms: Firstly, Ssd1 is induced during aging, sequestering mRNAs to P-bodies. Furthermore, Ssd1 overexpression in young cells reduced translation and extended lifespan, while loss of Ssd1 reduced the translational deficit of old cells and shortened lifespan. Secondly, phosphorylation of eIF2α, mediated by the stress kinase Gcn2, was elevated in old cells, contributing to the global reduction in translation without detectable induction of the downstream Gcn4 transcriptional activator. tRNA overexpression activated Gcn2 in young cells and extended lifespan in a manner dependent on Gcn4. Moreover, overexpression of Gcn4 sufficed to extend lifespan in an autophagy-dependent manner in the absence of changes in global translation, indicating that Gcn4-mediated autophagy induction is the ultimate downstream target of activated Gcn2, to extend lifespan.
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Affiliation(s)
- Zheng Hu
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
| | - Bo Xia
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, United States.,Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, United States
| | - Spike Dl Postnikoff
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
| | - Zih-Jie Shen
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
| | - Alin S Tomoiaga
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, United States.,Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, United States.,Manhattan College, Bronx, United States
| | - Troy A Harkness
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Canada
| | - Ja Hwan Seol
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, United States
| | - Wei Li
- Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States
| | - Kaifu Chen
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, United States.,Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, United States
| | - Jessica K Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, United States
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15
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Rapid Nuclear Exclusion of Hcm1 in Aging Saccharomyces cerevisiae Leads to Vacuolar Alkalization and Replicative Senescence. G3-GENES GENOMES GENETICS 2018. [PMID: 29519938 PMCID: PMC5940150 DOI: 10.1534/g3.118.200161] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The yeast, Saccharomyces cerevisiae, like other higher eukaryotes, undergo a finite number of cell divisions before exiting the cell cycle due to the effects of aging. Here, we show that yeast aging begins with the nuclear exclusion of Hcm1 in young cells, resulting in loss of acidic vacuoles. Autophagy is required for healthy aging in yeast, with proteins targeted for turnover by autophagy directed to the vacuole. Consistent with this, vacuolar acidity is necessary for vacuolar function and yeast longevity. Using yeast genetics and immunofluorescence microscopy, we confirm that vacuolar acidity plays a critical role in cell health and lifespan, and is potentially maintained by a series of Forkhead Box (Fox) transcription factors. An interconnected transcriptional network involving the Fox proteins (Fkh1, Fkh2 and Hcm1) are required for transcription of v-ATPase subunits and vacuolar acidity. As cells age, Hcm1 is rapidly excluded from the nucleus in young cells, blocking the expression of Hcm1 targets (Fkh1 and Fkh2), leading to loss of v-ATPase gene expression, reduced vacuolar acidification, increased α-syn-GFP vacuolar accumulation, and finally, diminished replicative lifespan (RLS). Loss of vacuolar acidity occurs about the same time as Hcm1 nuclear exclusion and is conserved; we have recently demonstrated that lysosomal alkalization similarly contributes to aging in C. elegans following a transition from progeny producing to post-reproductive life. Our data points to a molecular mechanism regulating vacuolar acidity that signals the end of RLS when acidification is lost.
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16
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Mohammad K, Dakik P, Medkour Y, McAuley M, Mitrofanova D, Titorenko VI. Some Metabolites Act as Second Messengers in Yeast Chronological Aging. Int J Mol Sci 2018; 19:ijms19030860. [PMID: 29543708 PMCID: PMC5877721 DOI: 10.3390/ijms19030860] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 02/06/2023] Open
Abstract
The concentrations of some key metabolic intermediates play essential roles in regulating the longevity of the chronologically aging yeast Saccharomyces cerevisiae. These key metabolites are detected by certain ligand-specific protein sensors that respond to concentration changes of the key metabolites by altering the efficiencies of longevity-defining cellular processes. The concentrations of the key metabolites that affect yeast chronological aging are controlled spatially and temporally. Here, we analyze mechanisms through which the spatiotemporal dynamics of changes in the concentrations of the key metabolites influence yeast chronological lifespan. Our analysis indicates that a distinct set of metabolites can act as second messengers that define the pace of yeast chronological aging. Molecules that can operate both as intermediates of yeast metabolism and as second messengers of yeast chronological aging include reduced nicotinamide adenine dinucleotide phosphate (NADPH), glycerol, trehalose, hydrogen peroxide, amino acids, sphingolipids, spermidine, hydrogen sulfide, acetic acid, ethanol, free fatty acids, and diacylglycerol. We discuss several properties that these second messengers of yeast chronological aging have in common with second messengers of signal transduction. We outline how these second messengers of yeast chronological aging elicit changes in cell functionality and viability in response to changes in the nutrient, energy, stress, and proliferation status of the cell.
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Affiliation(s)
- Karamat Mohammad
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Paméla Dakik
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Younes Medkour
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Mélissa McAuley
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Darya Mitrofanova
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Vladimir I Titorenko
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
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17
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Tyler JK, Johnson JE. The role of autophagy in the regulation of yeast life span. Ann N Y Acad Sci 2018; 1418:31-43. [PMID: 29363766 DOI: 10.1111/nyas.13549] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 01/07/2023]
Abstract
The goal of the aging field is to develop novel therapeutic interventions that extend human health span and reduce the burden of age-related disease. While organismal aging is a complex, multifactorial process, a popular theory is that cellular aging is a significant contributor to the progressive decline inherent to all multicellular organisms. To explore the molecular determinants that drive cellular aging, as well as how to retard them, researchers have utilized the highly genetically tractable budding yeast Saccharomyces cerevisiae. Indeed, every intervention known to extend both cellular and organismal health span was identified in yeast, underlining the power of this approach. Importantly, a growing body of work has implicated the process of autophagy as playing a critical role in the delay of aging. This review summarizes recent reports that have identified a role for autophagy, or autophagy factors in the extension of yeast life span. These studies demonstrate (1) that yeast remains an invaluable tool for the identification and characterization of conserved mechanisms that promote cellular longevity and are likely to be relevant to humans, and (2) that the process of autophagy has been implicated in nearly all known longevity-promoting manipulations and thus represents an ideal target for interventions aimed at improving human health span.
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Affiliation(s)
- Jessica K Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York
| | - Jay E Johnson
- Department of Biology, Orentreich Foundation for the Advancement of Science, Cold Spring, New York
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18
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Postnikoff SD, Johnson JE, Tyler JK. The integrated stress response in budding yeast lifespan extension. MICROBIAL CELL (GRAZ, AUSTRIA) 2017; 4:368-375. [PMID: 29167799 PMCID: PMC5695854 DOI: 10.15698/mic2017.11.597] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/05/2017] [Indexed: 12/18/2022]
Abstract
Aging is a complex, multi-factorial biological process shared by all living organisms. It is manifested by a gradual accumulation of molecular alterations that lead to the decline of normal physiological functions in a time-dependent fashion. The ultimate goal of aging research is to develop therapeutic means to extend human lifespan, while reducing susceptibility to many age-related diseases including cancer, as well as metabolic, cardiovascular and neurodegenerative disorders. However, this first requires elucidation of the causes of aging, which has been greatly facilitated by the use of model organisms. In particular, the budding yeast Saccharomyces cerevisiae has been invaluable in the identification of conserved molecular and cellular determinants of aging and for the development of approaches to manipulate these aging determinants to extend lifespan. Strikingly, where examined, virtually all means to experimentally extend lifespan result in the induction of cellular stress responses. This review describes growing evidence in yeast that activation of the integrated stress response contributes significantly to lifespan extension. These findings demonstrate that yeast remains a powerful model system for elucidating conserved mechanisms to achieve lifespan extension that are likely to drive therapeutic approaches to extend human lifespan and healthspan.
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Affiliation(s)
- Spike D.L. Postnikoff
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065
| | - Jay E. Johnson
- Orentreich Foundation for the Advancement of Science, Cold Spring, NY
| | - Jessica K. Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065
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19
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Menzies FM, Fleming A, Caricasole A, Bento CF, Andrews SP, Ashkenazi A, Füllgrabe J, Jackson A, Jimenez Sanchez M, Karabiyik C, Licitra F, Lopez Ramirez A, Pavel M, Puri C, Renna M, Ricketts T, Schlotawa L, Vicinanza M, Won H, Zhu Y, Skidmore J, Rubinsztein DC. Autophagy and Neurodegeneration: Pathogenic Mechanisms and Therapeutic Opportunities. Neuron 2017; 93:1015-1034. [PMID: 28279350 DOI: 10.1016/j.neuron.2017.01.022] [Citation(s) in RCA: 742] [Impact Index Per Article: 106.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 12/11/2022]
Abstract
Autophagy is a conserved pathway that delivers cytoplasmic contents to the lysosome for degradation. Here we consider its roles in neuronal health and disease. We review evidence from mouse knockout studies demonstrating the normal functions of autophagy as a protective factor against neurodegeneration associated with intracytoplasmic aggregate-prone protein accumulation as well as other roles, including in neuronal stem cell differentiation. We then describe how autophagy may be affected in a range of neurodegenerative diseases. Finally, we describe how autophagy upregulation may be a therapeutic strategy in a wide range of neurodegenerative conditions and consider possible pathways and druggable targets that may be suitable for this objective.
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Affiliation(s)
- Fiona M Menzies
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Angeleen Fleming
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Andrea Caricasole
- Alzheimer's Research UK Cambridge Drug Discovery Institute, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, UK
| | - Carla F Bento
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Stephen P Andrews
- Alzheimer's Research UK Cambridge Drug Discovery Institute, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, UK
| | - Avraham Ashkenazi
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Jens Füllgrabe
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Anne Jackson
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Maria Jimenez Sanchez
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Cansu Karabiyik
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Floriana Licitra
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Ana Lopez Ramirez
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Mariana Pavel
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Claudia Puri
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Maurizio Renna
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Thomas Ricketts
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Lars Schlotawa
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Mariella Vicinanza
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Hyeran Won
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Ye Zhu
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - John Skidmore
- Alzheimer's Research UK Cambridge Drug Discovery Institute, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, UK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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20
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Baxi K, Ghavidel A, Waddell B, Harkness TA, de Carvalho CE. Regulation of Lysosomal Function by the DAF-16 Forkhead Transcription Factor Couples Reproduction to Aging in Caenorhabditis elegans. Genetics 2017; 207:83-101. [PMID: 28696216 PMCID: PMC5586388 DOI: 10.1534/genetics.117.204222] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/03/2017] [Indexed: 02/06/2023] Open
Abstract
Aging in eukaryotes is accompanied by widespread deterioration of the somatic tissue. Yet, abolishing germ cells delays the age-dependent somatic decline in Caenorhabditis elegans In adult worms lacking germ cells, the activation of the DAF-9/DAF-12 steroid signaling pathway in the gonad recruits DAF-16 activity in the intestine to promote longevity-associated phenotypes. However, the impact of this pathway on the fitness of normally reproducing animals is less clear. Here, we explore the link between progeny production and somatic aging and identify the loss of lysosomal acidity-a critical regulator of the proteolytic output of these organelles-as a novel biomarker of aging in C. elegans The increase in lysosomal pH in older worms is not a passive consequence of aging, but instead is timed with the cessation of reproduction, and correlates with the reduction in proteostasis in early adult life. Our results further implicate the steroid signaling pathway and DAF-16 in dynamically regulating lysosomal pH in the intestine of wild-type worms in response to the reproductive cycle. In the intestine of reproducing worms, DAF-16 promotes acidic lysosomes by upregulating the expression of v-ATPase genes. These findings support a model in which protein clearance in the soma is linked to reproduction in the gonad via the active regulation of lysosomal acidification.
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Affiliation(s)
- Kunal Baxi
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Ata Ghavidel
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Brandon Waddell
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Troy A Harkness
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Carlos E de Carvalho
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
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21
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Mechanisms Underlying the Essential Role of Mitochondrial Membrane Lipids in Yeast Chronological Aging. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:2916985. [PMID: 28593023 PMCID: PMC5448074 DOI: 10.1155/2017/2916985] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/18/2017] [Indexed: 12/12/2022]
Abstract
The functional state of mitochondria is vital to cellular and organismal aging in eukaryotes across phyla. Studies in the yeast Saccharomyces cerevisiae have provided evidence that age-related changes in some aspects of mitochondrial functionality can create certain molecular signals. These signals can then define the rate of cellular aging by altering unidirectional and bidirectional communications between mitochondria and other organelles. Several aspects of mitochondrial functionality are known to impact the replicative and/or chronological modes of yeast aging. They include mitochondrial electron transport, membrane potential, reactive oxygen species, and protein synthesis and proteostasis, as well as mitochondrial synthesis of iron-sulfur clusters, amino acids, and NADPH. Our recent findings have revealed that the composition of mitochondrial membrane lipids is one of the key aspects of mitochondrial functionality affecting yeast chronological aging. We demonstrated that exogenously added lithocholic bile acid can delay chronological aging in yeast because it elicits specific changes in mitochondrial membrane lipids. These changes allow mitochondria to operate as signaling platforms that delay yeast chronological aging by orchestrating an institution and maintenance of a distinct cellular pattern. In this review, we discuss molecular and cellular mechanisms underlying the essential role of mitochondrial membrane lipids in yeast chronological aging.
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22
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Kakish J, Allen KJH, Harkness TA, Krol ES, Lee JS. Novel Dimer Compounds That Bind α-Synuclein Can Rescue Cell Growth in a Yeast Model Overexpressing α-Synuclein. A Possible Prevention Strategy for Parkinson's Disease. ACS Chem Neurosci 2016; 7:1671-1680. [PMID: 27673434 DOI: 10.1021/acschemneuro.6b00209] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The misfolding of α-synuclein is a critical event in the death of dopaminergic neurons and the progression of Parkinson's disease. Previously, it was suggested that drugs, which bind to α-synuclein and form a loop structure between the N- and C-termini, tend to be neuroprotective, whereas others, which cause a more compact structure, tend to be neurotoxic. To improve the binding to α-synuclein, eight novel compounds were synthesized from a caffeine scaffold attached to (R,S)-1-aminoindan, (R,S)-nicotine, and metformin, and their binding to α-synuclein determined through nanopore analysis and isothermal titration calorimetry. The ability of the dimers to interact with α-synuclein in a cell system was assayed in a yeast model of PD which expresses an AS-GFP (α-synuclein-Green Fluorescent Protein) construct under the control of a galactose promoter. In 5 mM galactose this yeast strain will not grow and large cytoplasmic foci are observed by fluorescent microscopy. Two of the dimers, C8-6-I and C8-6-N, at a concentration of 0.1 μM allowed the yeast to grow normally in 5 mM galactose and the AS-GFP became localized to the periphery of the cell. Both dimers were superior when compared to the monomeric compounds. The presence of the dimers also caused the disappearance of preformed cytoplasmic foci. Nanopore analysis of C8-6-I and C8-6-N were consistent with simultaneous binding to both the N- and C-terminus of α-synuclein but the binding constants were only 105 M-1.
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Affiliation(s)
- Joe Kakish
- Department of Biochemistry, ‡Drug Discovery and Development Research Group, College
of Pharmacy and Nutrition, and §Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Canada S7N 0W0
| | - Kevin J. H. Allen
- Department of Biochemistry, ‡Drug Discovery and Development Research Group, College
of Pharmacy and Nutrition, and §Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Canada S7N 0W0
| | - Troy A. Harkness
- Department of Biochemistry, ‡Drug Discovery and Development Research Group, College
of Pharmacy and Nutrition, and §Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Canada S7N 0W0
| | - Ed S. Krol
- Department of Biochemistry, ‡Drug Discovery and Development Research Group, College
of Pharmacy and Nutrition, and §Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Canada S7N 0W0
| | - Jeremy S. Lee
- Department of Biochemistry, ‡Drug Discovery and Development Research Group, College
of Pharmacy and Nutrition, and §Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Canada S7N 0W0
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23
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Dakik P, Titorenko VI. Communications between Mitochondria, the Nucleus, Vacuoles, Peroxisomes, the Endoplasmic Reticulum, the Plasma Membrane, Lipid Droplets, and the Cytosol during Yeast Chronological Aging. Front Genet 2016; 7:177. [PMID: 27729926 PMCID: PMC5037234 DOI: 10.3389/fgene.2016.00177] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/16/2016] [Indexed: 12/14/2022] Open
Abstract
Studies employing the budding yeast Saccharomyces cerevisiae as a model organism have provided deep insights into molecular mechanisms of cellular and organismal aging in multicellular eukaryotes and have demonstrated that the main features of biological aging are evolutionarily conserved. Aging in S. cerevisiae is studied by measuring replicative or chronological lifespan. Yeast replicative aging is likely to model aging of mitotically competent human cell types, while yeast chronological aging is believed to mimic aging of post-mitotic human cell types. Emergent evidence implies that various organelle-organelle and organelle-cytosol communications play essential roles in chronological aging of S. cerevisiae. The molecular mechanisms underlying the vital roles of intercompartmental communications in yeast chronological aging have begun to emerge. The scope of this review is to critically analyze recent progress in understanding such mechanisms. Our analysis suggests a model for how temporally and spatially coordinated movements of certain metabolites between various cellular compartments impact yeast chronological aging. In our model, diverse changes in these key metabolites are restricted to critical longevity-defining periods of chronological lifespan. In each of these periods, a limited set of proteins responds to such changes of the metabolites by altering the rate and efficiency of a certain cellular process essential for longevity regulation. Spatiotemporal dynamics of alterations in these longevity-defining cellular processes orchestrates the development and maintenance of a pro- or anti-aging cellular pattern.
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Affiliation(s)
- Pamela Dakik
- Department of Biology, Faculty of Arts and Science, Concordia University Montreal, PQ, Canada
| | - Vladimir I Titorenko
- Department of Biology, Faculty of Arts and Science, Concordia University Montreal, PQ, Canada
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