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Napolitano G, Fasciolo G, Muscari Tomajoli MT, Venditti P. Changes in the Mitochondria in the Aging Process-Can α-Tocopherol Affect Them? Int J Mol Sci 2023; 24:12453. [PMID: 37569829 PMCID: PMC10419829 DOI: 10.3390/ijms241512453] [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: 06/30/2023] [Revised: 07/28/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Aerobic organisms use molecular oxygen in several reactions, including those in which the oxidation of substrate molecules is coupled to oxygen reduction to produce large amounts of metabolic energy. The utilization of oxygen is associated with the production of ROS, which can damage biological macromolecules but also act as signaling molecules, regulating numerous cellular processes. Mitochondria are the cellular sites where most of the metabolic energy is produced and perform numerous physiological functions by acting as regulatory hubs of cellular metabolism. They retain the remnants of their bacterial ancestors, including an independent genome that encodes part of their protein equipment; they have an accurate quality control system; and control of cellular functions also depends on communication with the nucleus. During aging, mitochondria can undergo dysfunctions, some of which are mediated by ROS. In this review, after a description of how aging affects the mitochondrial quality and quality control system and the involvement of mitochondria in inflammation, we report information on how vitamin E, the main fat-soluble antioxidant, can protect mitochondria from age-related changes. The information in this regard is scarce and limited to some tissues and some aspects of mitochondrial alterations in aging. Improving knowledge of the effects of vitamin E on aging is essential to defining an optimal strategy for healthy aging.
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Affiliation(s)
- Gaetana Napolitano
- Department of Science and Technology, University of Naples Parthenope, Via Acton n. 38, I-80133 Naples, Italy; (G.N.); (M.T.M.T.)
| | - Gianluca Fasciolo
- Department of Biology, University of Naples ‘Napoli Federico II’, Complesso Universitario di Monte Sant’Angelo, Via Cinthia, I-80126 Naples, Italy;
| | - Maria Teresa Muscari Tomajoli
- Department of Science and Technology, University of Naples Parthenope, Via Acton n. 38, I-80133 Naples, Italy; (G.N.); (M.T.M.T.)
| | - Paola Venditti
- Department of Biology, University of Naples ‘Napoli Federico II’, Complesso Universitario di Monte Sant’Angelo, Via Cinthia, I-80126 Naples, Italy;
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2
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Vegetables and Their Bioactive Compounds as Anti-Aging Drugs. Molecules 2022; 27:molecules27072316. [PMID: 35408714 PMCID: PMC9000296 DOI: 10.3390/molecules27072316] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 12/27/2022] Open
Abstract
Aging is a continuous process over time that is mainly related to natural alterations in mechanical–biological processes. This phenomenon is due to several factors, including the time and energy of biological processes. Aging can be attributed to biological factors such as oxidative stress, cell longevity, and stem cell senescence. Currently, aging is associated with several diseases, such as neurodegenerative diseases, cancer, and other diseases related to oxidative stress. In addition, certain natural molecules, including those derived from vegetables, have shown the ability to delay the aging process. Their effects are linked to different mechanisms of action, such as tissue regeneration and the activation of longevity and anti-senescence genes. The present work discusses the impact of vegetables, and bioactive compounds isolated from vegetables, against the physiological and pathological aging process and accompanying human diseases.
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3
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Camandona VDL, Rios-Anjos RM, Alegria TGP, Pereira F, Bicev RN, da Cunha FM, Digiampietri LA, de Barros MH, Netto LES, Ferreira-Junior JR. Expression of human HSP27 in yeast extends replicative lifespan and uncovers a hormetic response. Biogerontology 2020; 21:559-575. [PMID: 32189112 DOI: 10.1007/s10522-020-09869-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/13/2020] [Indexed: 01/20/2023]
Abstract
Human HSP27 is a small heat shock protein that modulates the ability of cells to respond to heat shock and oxidative stress, and also functions as a chaperone independent of ATP, participating in the proteasomal degradation of proteins. The expression of HSP27 is associated with survival in mammalian cells. In cancer cells, it confers resistance to chemotherapy; in neurons, HSP27 has a positive effect on neuronal viability in models of Alzheimer's and Parkinson's diseases. To better understand the mechanism by which HSP27 expression contributes to cell survival, we expressed human HSP27 in the budding yeast Saccharomyces cerevisiae under control of different mutant TEF promoters, that conferred nine levels of graded basal expression, and showed that replicative lifespan and proteasomal activity increase as well as the resistance to oxidative and thermal stresses. The profile of these phenotypes display a dose-response effect characteristic of hormesis, an adaptive phenomenon that is observed when cells are exposed to increasing amounts of stress or toxic substances. The hormetic response correlates with changes in expression levels of HSP27 and also with its oligomeric states when correlated to survival assays. Our results indicate that fine tuning of HSP27 concentration could be used as a strategy for cancer therapy, and also for improving neuronal survival in neurodegenerative diseases.
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Affiliation(s)
| | | | - Thiago Geronimo Pires Alegria
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Fábio Pereira
- Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, Brazil
| | | | | | | | - Mário Henrique de Barros
- Departamento de Microbiologia - Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Luis Eduardo Soares Netto
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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4
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Zainabadi K. A brief history of modern aging research. Exp Gerontol 2018; 104:35-42. [DOI: 10.1016/j.exger.2018.01.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 01/15/2018] [Indexed: 11/16/2022]
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5
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Honigberg SM. Similar environments but diverse fates: Responses of budding yeast to nutrient deprivation. MICROBIAL CELL 2016; 3:302-328. [PMID: 27917388 PMCID: PMC5134742 DOI: 10.15698/mic2016.08.516] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diploid budding yeast (Saccharomyces cerevisiae) can adopt one
of several alternative differentiation fates in response to nutrient limitation,
and each of these fates provides distinct biological functions. When different
strain backgrounds are taken into account, these various fates occur in response
to similar environmental cues, are regulated by the same signal transduction
pathways, and share many of the same master regulators. I propose that the
relationships between fate choice, environmental cues and signaling pathways are
not Boolean, but involve graded levels of signals, pathway activation and
master-regulator activity. In the absence of large differences between
environmental cues, small differences in the concentration of cues may be
reinforced by cell-to-cell signals. These signals are particularly essential for
fate determination within communities, such as colonies and biofilms, where fate
choice varies dramatically from one region of the community to another. The lack
of Boolean relationships between cues, signaling pathways, master regulators and
cell fates may allow yeast communities to respond appropriately to the wide
range of environments they encounter in nature.
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Affiliation(s)
- Saul M Honigberg
- Division of Cell Biology and Biophysics, University of Missouri-Kansas City, 5007 Rockhill Rd, Kansas City MO 64110, USA
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6
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Chadwick SR, Pananos AD, Di Gregorio SE, Park AE, Etedali-Zadeh P, Duennwald ML, Lajoie P. A Toolbox for Rapid Quantitative Assessment of Chronological Lifespan and Survival inSaccharomyces cerevisiae. Traffic 2016; 17:689-703. [DOI: 10.1111/tra.12391] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/01/2016] [Accepted: 03/01/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Sarah R. Chadwick
- Department of Anatomy and Cell Biology; The University of Western Ontario; London N6A 5C1 Canada
| | | | - Sonja E. Di Gregorio
- Department of Pathology and Laboratory Medicine; The University of Western Ontario; London N6A 5C1 Canada
| | - Anna E. Park
- 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
| | - 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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7
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Bitto A, Wang AM, Bennett CF, Kaeberlein M. Biochemical Genetic Pathways that Modulate Aging in Multiple Species. Cold Spring Harb Perspect Med 2015; 5:5/11/a025114. [PMID: 26525455 DOI: 10.1101/cshperspect.a025114] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mechanisms underlying biological aging have been extensively studied in the past 20 years with the avail of mainly four model organisms: the budding yeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans, the fruitfly Drosophila melanogaster, and the domestic mouse Mus musculus. Extensive research in these four model organisms has identified a few conserved genetic pathways that affect longevity as well as metabolism and development. Here, we review how the mechanistic target of rapamycin (mTOR), sirtuins, adenosine monophosphate-activated protein kinase (AMPK), growth hormone/insulin-like growth factor 1 (IGF-1), and mitochondrial stress-signaling pathways influence aging and life span in the aforementioned models and their possible implications for delaying aging in humans. We also draw some connections between these biochemical pathways and comment on what new developments aging research will likely bring in the near future.
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Affiliation(s)
- Alessandro Bitto
- Department of Pathology, University of Washington, Seattle, Washington 98195
| | - Adrienne M Wang
- Department of Pathology, University of Washington, Seattle, Washington 98195
| | | | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, Washington 98195
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8
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Raynes R, Brunquell J, Westerheide SD. Stress Inducibility of SIRT1 and Its Role in Cytoprotection and Cancer. Genes Cancer 2013; 4:172-82. [PMID: 24020008 DOI: 10.1177/1947601913484497] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cells must continuously respond to stressful insults via the upregulation of cytoprotective pathways. The longevity factor and deacetylase SIRT1 plays a critical role in coordinating this cellular response to stress. SIRT1 activity and levels are regulated by cellular stressors, including metabolic, genotoxic, oxidative, and proteotoxic stress. As a stress sensor, SIRT1 impacts cell survival by deacetylating substrate proteins to drive the cell towards a cytoprotective pathway. Extreme stress conditions, however, can cause SIRT1 to lead cells down an apoptotic pathway instead. SIRT1 is frequently dysregulated in cancer cells and has been characterized to have a dual role as both an oncogene and a tumor suppressor, likely due to its pivotal function in regulating cytoprotection. Recently, the ability of SIRT1 to regulate HSF1-dependent induction of the heat shock response has highlighted another pathway through which SIRT1 can modulate cytoprotection. Activation of HSF1 results in the production of cytoprotective chaperones that can facilitate the transformed phenotype of cancer cells. In this review, we discuss the stress-dependent regulation of SIRT1. We highlight the role of SIRT1 in stress management and cytoprotection and emphasize SIRT1-dependent activation of HSF1 as a potential mechanism for cancer promotion.
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Affiliation(s)
- Rachel Raynes
- Department of Cell Biology, Microbiology and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, FL, USA
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9
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Huberts DHEW, Janssens GE, Lee SS, Vizcarra IA, Heinemann M. Continuous high-resolution microscopic observation of replicative aging in budding yeast. J Vis Exp 2013:e50143. [PMID: 23995364 DOI: 10.3791/50143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We demonstrate the use of a simple microfluidic setup, in which single budding yeast cells can be tracked throughout their entire lifespan. The microfluidic chip exploits the size difference between mother and daughter cells using an array of micropads. Upon loading, cells are trapped underneath these micropads, because the distance between the micropad and cover glass is similar to the diameter of a yeast cell (3-4 μm). After the loading procedure, culture medium is continuously flushed through the chip, which not only creates a constant and defined environment throughout the entire experiment, but also flushes out the emerging daughter cells, which are not retained underneath the pads due to their smaller size. The setup retains mother cells so efficiently that in a single experiment up to 50 individual cells can be monitored in a fully automated manner for 5 days or, if necessary, longer. In addition, the excellent optical properties of the chip allow high-resolution imaging of cells during the entire aging process.
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Affiliation(s)
- Daphne H E W Huberts
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen
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10
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Delaney JR, Chou A, Olsen B, Carr D, Murakami C, Ahmed U, Sim S, An EH, Castanza AS, Fletcher M, Higgins S, Holmberg M, Hui J, Jelic M, Jeong KS, Kim JR, Klum S, Liao E, Lin MS, Lo W, Miller H, Moller R, Peng ZJ, Pollard T, Pradeep P, Pruett D, Rai D, Ros V, Schleit J, Schuster A, Singh M, Spector BL, Sutphin GL, Wang AM, Wasko BM, Vander Wende H, Kennedy BK, Kaeberlein M. End-of-life cell cycle arrest contributes to stochasticity of yeast replicative aging. FEMS Yeast Res 2013; 13:267-76. [PMID: 23336757 DOI: 10.1111/1567-1364.12030] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 01/14/2013] [Accepted: 01/14/2013] [Indexed: 11/28/2022] Open
Abstract
There is growing evidence that stochastic events play an important role in determining individual longevity. Studies in model organisms have demonstrated that genetically identical populations maintained under apparently equivalent environmental conditions display individual variation in life span that can be modeled by the Gompertz-Makeham law of mortality. Here, we report that within genetically identical haploid and diploid wild-type populations, shorter-lived cells tend to arrest in a budded state, while cells that arrest in an unbudded state are significantly longer-lived. This relationship is particularly notable in diploid BY4743 cells, where mother cells that arrest in a budded state have a shorter mean life span (25.6 vs. 35.6) and larger coefficient of variance with respect to individual life span (0.42 vs. 0.32) than cells that arrest in an unbudded state. Mutations that cause genomic instability tend to shorten life span and increase the proportion of the population that arrest in a budded state. These observations suggest that randomly occurring damage may contribute to stochasticity during replicative aging by causing a subset of the population to terminally arrest prematurely in the S or G2 phase of the cell cycle.
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Affiliation(s)
- Joe R Delaney
- Department of Pathology, University of Washington, Seattle, WA 98195-7470, USA
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11
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Schleit J, Wasko BM, Kaeberlein M. Yeast as a model to understand the interaction between genotype and the response to calorie restriction. FEBS Lett 2012; 586:2868-73. [PMID: 22828279 PMCID: PMC4016815 DOI: 10.1016/j.febslet.2012.07.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 07/13/2012] [Accepted: 07/16/2012] [Indexed: 12/01/2022]
Abstract
Calorie restriction is reported to enhance survival and delay the onset of age-related decline in many different species. Several proteins have been proposed to play a role in mediating the response to calorie restriction, including the target of rapamycin kinase, sirtuins, and AMP kinase. An enhanced mechanistic understanding of calorie restriction has popularized the concept of "calorie restriction mimetics", drugs that mimic the beneficial effects of caloire restriction without requiring a reduction in nutrient intake. In theory, such drugs should delay the onset and progression of multiple age-related diseases, similar to calorie restriction in mammals. Despite the potential benefits of such calorie restriction mimetics, however, relatively little is known about the interaction between genetic variation and individual response to calorie restriction. Limited evidence from model systems indicates that genotype plays a large role in determining both the magnitude and direction of effect that calorie restriction has on longevity. Here we present an overview of these data from the perspective of using yeast as a model to study aging and describe an approach we are taking to further characterize the molecular mechanisms underlying genotype-dependent responses to calorie restriction.
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Affiliation(s)
- Jennifer Schleit
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Brian M. Wasko
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA, USA
- Institute of Aging Research, Guangdong Medical College, Dongguan 523808, China
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12
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Vaubel RA, Rustin P, Isaya G. Mutations in the dimer interface of dihydrolipoamide dehydrogenase promote site-specific oxidative damages in yeast and human cells. J Biol Chem 2011; 286:40232-45. [PMID: 21930696 PMCID: PMC3220568 DOI: 10.1074/jbc.m111.274415] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 09/13/2011] [Indexed: 12/31/2022] Open
Abstract
Dihydrolipoamide dehydrogenase (DLD) is a multifunctional protein well characterized as the E3 component of the pyruvate dehydrogenase and α-ketoglutarate dehydrogenase complexes. Previously, conditions predicted to destabilize the DLD dimer revealed that DLD could also function as a diaphorase and serine protease. However, the relevance of these cryptic activities remained undefined. We analyzed human DLD mutations linked to strikingly different clinical phenotypes, including E340K, D444V, R447G, and R460G in the dimer interface domain that are responsible for severe multisystem disorders of infancy and G194C in the NAD(+)-binding domain that is typically associated with milder presentations. In vitro, all of these mutations decreased to various degrees dihydrolipoamide dehydrogenase activity, whereas dimer interface mutations also enhanced proteolytic and/or diaphorase activity. Human DLD proteins carrying each individual mutation complemented fully the respiratory-deficient phenotype of yeast cells lacking endogenous DLD even when residual dihydrolipoamide dehydrogenase activity was as low as 21% of controls. However, under elevated oxidative stress, expression of DLD proteins with dimer interface mutations greatly accelerated the loss of respiratory function, resulting from enhanced oxidative damage to the lipoic acid cofactor of pyruvate dehydrogenase and α-ketoglutarate dehydrogenase and other mitochondrial targets. This effect was not observed with the G194C mutation or a mutation that disrupts the proteolytic active site of DLD. As in yeast, lipoic acid cofactor was damaged in human D444V-homozygous fibroblasts after exposure to oxidative stress. We conclude that the cryptic activities of DLD promote oxidative damage to neighboring molecules and thus contribute to the clinical severity of DLD mutations.
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Affiliation(s)
- Rachael A. Vaubel
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, Mayo Clinic, Rochester Minnesota 55905
| | - Pierre Rustin
- INSERM U676 Hôpital Robert Debré, F-75019 Paris, France, and
- Université Paris 7, Faculté de Médecine Denis Diderot, IFR02 Paris, France
| | - Grazia Isaya
- From the Departments of Pediatric and Adolescent Medicine and Biochemistry and Molecular Biology, Mayo Clinic, Rochester Minnesota 55905
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13
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Confronting Cellular Heterogeneity in Studies of Protein Metabolism and Homeostasis in Aging Research. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 694:234-44. [DOI: 10.1007/978-1-4419-7002-2_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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14
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Bush EW, McKinsey TA. Targeting histone deacetylases for heart failure. Expert Opin Ther Targets 2009; 13:767-84. [DOI: 10.1517/14728220902939161] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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15
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Gakh O, Smith DY, Isaya G. Assembly of the iron-binding protein frataxin in Saccharomyces cerevisiae responds to dynamic changes in mitochondrial iron influx and stress level. J Biol Chem 2008; 283:31500-10. [PMID: 18784075 PMCID: PMC2581586 DOI: 10.1074/jbc.m805415200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 09/08/2008] [Indexed: 11/06/2022] Open
Abstract
Defects in frataxin result in Friedreich ataxia, a genetic disease characterized by early onset of neurodegeneration, cardiomyopathy, and diabetes. Frataxin is a conserved mitochondrial protein that controls iron needed for iron-sulfur cluster assembly and heme synthesis and also detoxifies excess iron. Studies in vitro have shown that either monomeric or oligomeric frataxin delivers iron to other proteins, whereas ferritin-like frataxin particles convert redox-active iron to an inert mineral. We have investigated how these different forms of frataxin are regulated in vivo. In Saccharomyces cerevisiae, only monomeric yeast frataxin (Yfh1) was detected in unstressed cells when mitochondrial iron uptake was maintained at a steady, low nanomolar level. Increments in mitochondrial iron uptake induced stepwise assembly of Yfh1 species ranging from trimer to > or = 24-mer, independent of interactions between Yfh1 and its major iron-binding partners, Isu1/Nfs1 or aconitase. The rate-limiting step in Yfh1 assembly was a structural transition that preceded conversion of monomer to trimer. This step was induced, independently or synergistically, by mitochondrial iron increments, overexpression of wild type Yfh1 monomer, mutations that stabilize Yfh1 trimer, or heat stress. Faster assembly kinetics correlated with reduced oxidative damage and higher levels of aconitase activity, respiratory capacity, and cell survival. However, deregulation of Yfh1 assembly resulted in Yfh1 aggregation, aconitase sequestration, and mitochondrial DNA depletion. The data suggest that Yfh1 assembly responds to dynamic changes in mitochondrial iron uptake or stress exposure in a highly controlled fashion and that this may enable frataxin to simultaneously promote respiratory function and stress tolerance.
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Affiliation(s)
- Oleksandr Gakh
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, College of Medicine, Rochester, Minnesota 55905, USA
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16
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Gitler AD. Beer and bread to brains and beyond: can yeast cells teach us about neurodegenerative disease? Neurosignals 2007; 16:52-62. [PMID: 18097160 DOI: 10.1159/000109759] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
For millennia, humans have harnessed the astonishing power of yeast, producing such culinary masterpieces as bread, beer and wine. Therefore, in this new millennium, is it very farfetched to ask if we can also use yeast to unlock some of the modern day mysteries of human disease? Remarkably, these seemingly simple cells possess most of the same basic cellular machinery as the neurons in the brain. We and others have been using the baker's yeast, Saccharomyces cerevisiae, as a model system to study the mechanisms of devastating neurodegenerative diseases such as Parkinson's, Huntington's, Alzheimer's and amyotrophic lateral sclerosis. While very different in their pathophysiology, they are collectively referred to as protein-misfolding disorders because of the presence of misfolded and aggregated forms of various proteins in the brains of affected individuals. Using yeast genetics and the latest high-throughput screening technologies, we have identified some of the potential causes underpinning these disorders and discovered conserved genes that have proven effective in preventing neuron loss in animal models. Thus, these genes represent new potential drug targets. In this review, I highlight recent work investigating mechanisms of cellular toxicity in a yeast Parkinson's disease model and discuss how similar approaches are being applied to additional neurodegenerative diseases.
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Affiliation(s)
- Aaron D Gitler
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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Abstract
The use of genomic technologies in biogerontology has the potential to greatly enhance our understanding of human ageing. High-throughput screens for alleles correlated with survival in long-lived people have uncovered novel genes involved in age-associated disease. Genome-wide longevity studies in simple eukaryotes are identifying evolutionarily conserved pathways that determine longevity. It is hoped that validation of these 'public' aspects of ageing in mice, along with analyses of variation in candidate human ageing genes, will provide targets for future interventions to slow the ageing process and retard the onset of age-associated pathologies.
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Affiliation(s)
- Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA.
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18
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Powers RW, Kaeberlein M, Caldwell SD, Kennedy BK, Fields S. Extension of chronological life span in yeast by decreased TOR pathway signaling. Genes Dev 2006; 20:174-84. [PMID: 16418483 PMCID: PMC1356109 DOI: 10.1101/gad.1381406] [Citation(s) in RCA: 733] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Chronological life span (CLS) in Saccharomyces cerevisiae, defined as the time cells in a stationary phase culture remain viable, has been proposed as a model for the aging of post-mitotic tissues in mammals. We developed a high-throughput assay to determine CLS for approximately 4800 single-gene deletion strains of yeast, and identified long-lived strains carrying mutations in the conserved TOR pathway. TOR signaling regulates multiple cellular processes in response to nutrients, especially amino acids, raising the possibility that decreased TOR signaling mediates life span extension by calorie restriction. In support of this possibility, removal of either asparagine or glutamate from the media significantly increased stationary phase survival. Pharmacological inhibition of TOR signaling by methionine sulfoximine or rapamycin also increased CLS. Decreased TOR activity also promoted increased accumulation of storage carbohydrates and enhanced stress resistance and nuclear relocalization of the stress-related transcription factor Msn2. We propose that up-regulation of a highly conserved response to starvation-induced stress is important for life span extension by decreased TOR signaling in yeast and higher eukaryotes.
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Affiliation(s)
- R Wilson Powers
- Department of Genome Sciences and Medicine, The Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
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19
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Gakh O, Park S, Liu G, Macomber L, Imlay JA, Ferreira GC, Isaya G. Mitochondrial iron detoxification is a primary function of frataxin that limits oxidative damage and preserves cell longevity. Hum Mol Genet 2006; 15:467-79. [PMID: 16371422 DOI: 10.1093/hmg/ddi461] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Friedreich ataxia is a severe autosomal-recessive disease characterized by neurodegeneration, cardiomyopathy and diabetes, resulting from reduced synthesis of the mitochondrial protein frataxin. Although frataxin is ubiquitously expressed, frataxin deficiency leads to a selective loss of dorsal root ganglia neurons, cardiomyocytes and pancreatic beta cells. How frataxin normally promotes survival of these particular cells is the subject of intense debate. The predominant view is that frataxin sustains mitochondrial energy production and other cellular functions by providing iron for heme synthesis and iron-sulfur cluster (ISC) assembly and repair. We have proposed that frataxin not only promotes the biogenesis of iron-containing enzymes, but also detoxifies surplus iron thereby affording a critical anti-oxidant mechanism. These two functions have been difficult to tease apart, however, and the physiologic role of iron detoxification by frataxin has not yet been demonstrated in vivo. Here, we describe mutations that specifically impair the ferroxidation or mineralization activity of yeast frataxin, which are necessary for iron detoxification but do not affect the iron chaperone function of the protein. These mutations increase the sensitivity of yeast cells to oxidative stress, shortening chronological life span and precluding survival in the absence of the anti-oxidant enzyme superoxide dismutase. Thus, the role of frataxin is not limited to promoting ISC assembly or heme synthesis. Iron detoxification is another function of frataxin relevant to anti-oxidant defense and cell longevity that could play a critical role in the metabolically demanding environment of non-dividing neuronal, cardiac and pancreatic beta cells.
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Affiliation(s)
- Oleksandr Gakh
- Department of Pediatric, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Kaeberlein M, Kirkland KT, Fields S, Kennedy BK. Sir2-independent life span extension by calorie restriction in yeast. PLoS Biol 2004; 2:E296. [PMID: 15328540 PMCID: PMC514491 DOI: 10.1371/journal.pbio.0020296] [Citation(s) in RCA: 335] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 07/07/2004] [Indexed: 01/12/2023] Open
Abstract
Calorie restriction slows aging and increases life span in many organisms. In yeast, a mechanistic explanation has been proposed whereby calorie restriction slows aging by activating Sir2. Here we report the identification of a Sir2-independent pathway responsible for a majority of the longevity benefit associated with calorie restriction. Deletion of FOB1 and overexpression of SIR2 have been previously found to increase life span by reducing the levels of toxic rDNA circles in aged mother cells. We find that combining calorie restriction with either of these genetic interventions dramatically enhances longevity, resulting in the longest-lived yeast strain reported thus far. Further, calorie restriction results in a greater life span extension in cells lacking both Sir2 and Fob1 than in cells where Sir2 is present. These findings indicate that Sir2 and calorie restriction act in parallel pathways to promote longevity in yeast and, perhaps, higher eukaryotes. This study indicates that calorie restriction and Sir2 promote longevity in yeast through distinct pathways. This undermines the accepted view, and has implications for aging in higher organisms
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Affiliation(s)
- Matt Kaeberlein
- 1Departments of Genome Sciences and Medicine, University of WashingtonSeattle, Washington, United States of America
| | - Kathryn T Kirkland
- 2Department of Biochemistry, University of WashingtonSeattle, Washington, United States of America
| | - Stanley Fields
- 1Departments of Genome Sciences and Medicine, University of WashingtonSeattle, Washington, United States of America
- 3Howard Hughes Medical Institute, University of WashingtonSeattle, WashingtonUnited States of America
| | - Brian K Kennedy
- 2Department of Biochemistry, University of WashingtonSeattle, Washington, United States of America
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