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Calabrese EJ, Nascarella M, Pressman P, Hayes AW, Dhawan G, Kapoor R, Calabrese V, Agathokleous E. Hormesis determines lifespan. Ageing Res Rev 2024; 94:102181. [PMID: 38182079 DOI: 10.1016/j.arr.2023.102181] [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: 10/05/2023] [Revised: 12/27/2023] [Accepted: 12/30/2023] [Indexed: 01/07/2024]
Abstract
This paper addresses how long lifespan can be extended via multiple interventions, such as dietary supplements [e.g., curcumin, resveratrol, sulforaphane, complex phytochemical mixtures (e.g., Moringa, Rhodiola)], pharmaceutical agents (e.g., metformin), caloric restriction, intermittent fasting, exercise and other activities. This evaluation was framed within the context of hormesis, a biphasic dose response with specific quantitative features describing the limits of biological/phenotypic plasticity for integrative biological endpoints (e.g., cell proliferation, memory, fecundity, growth, tissue repair, stem cell population expansion/differentiation, longevity). Evaluation of several hundred lifespan extending agents using yeast, nematode (Caenorhabditis elegans), multiple insect and other invertebrate and vertebrate models (e.g., fish, rodents), revealed they responded in a manner [average (mean/median) and maximum lifespans] consistent with the quantitative features [i.e., 30-60% greater at maximum (Hormesis Rule)] of the hormetic dose response. These lifespan extension features were independent of biological model, inducing agent, endpoints measured and mechanism. These findings indicate that hormesis describes the capacity to extend life via numerous agents and activities and that the magnitude of lifespan extension is modest, in the percentage, not fold, range. These findings have important implications for human aging, genetic diseases/environmental stresses and lifespan extension, as well as public health practices and long-term societal resource planning.
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Affiliation(s)
- Edward J Calabrese
- School of Public Health and Health Sciences; University of Massachusetts, Morrill I - Room N344, Amherst, MA 01003, USA.
| | - Marc Nascarella
- Mass College of Pharmacy and Health Sciences University; School of Arts and Sciences, 179 Longwood Avenue, Boston, MA 02115, USA
| | - Peter Pressman
- University of Maine, 5728 Fernald Hall, Room 201, Orono, ME 04469, USA
| | - A Wallace Hayes
- Center for Environmental Occupational Risk Analysis and Management; College of Public Health; University of South Florida, Tampa, FL, USA
| | - Gaurav Dhawan
- Sri Guru Ram Das (SGRD) University of Health Sciences, Amritsar, India
| | - Rachna Kapoor
- Saint Francis Hospital and Medical Center, Hartford, CT, USA
| | - Vittorio Calabrese
- Department of Biomedical and Biotechnological Sciences, School of Medicine University of Catania, Via Santa Sofia 97, Catania 95123, Italy
| | - Evgenios Agathokleous
- School of Ecology and Applied Meteorology; Nanjing University of Information Science & Technology; Nanjing 210044, China
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Tippetts TS, Sieber MH, Solmonson A. Beyond energy and growth: the role of metabolism in developmental signaling, cell behavior and diapause. Development 2023; 150:dev201610. [PMID: 37883062 PMCID: PMC10652041 DOI: 10.1242/dev.201610] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Metabolism is crucial for development through supporting cell growth, energy production, establishing cell identity, developmental signaling and pattern formation. In many model systems, development occurs alongside metabolic transitions as cells differentiate and specialize in metabolism that supports new functions. Some cells exhibit metabolic flexibility to circumvent mutations or aberrant signaling, whereas other cell types require specific nutrients for developmental progress. Metabolic gradients and protein modifications enable pattern formation and cell communication. On an organism level, inadequate nutrients or stress can limit germ cell maturation, implantation and maturity through diapause, which slows metabolic activities until embryonic activation under improved environmental conditions.
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Affiliation(s)
- Trevor S. Tippetts
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Matthew H. Sieber
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ashley Solmonson
- Laboratory of Developmental Metabolism and Placental Biology, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Zhou L, Luo S, Wang X, Zhou Y, Zhang Y, Zhu S, Chen T, Feng S, Yuan M, Ding C. Blumea laciniata protected Hep G2 cells and Caenorhabditis elegans against acrylamide-induced toxicity via insulin/IGF-1 signaling pathway. Food Chem Toxicol 2021; 158:112667. [PMID: 34762976 DOI: 10.1016/j.fct.2021.112667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/30/2021] [Accepted: 11/07/2021] [Indexed: 02/07/2023]
Abstract
Acrylamide (AC), a proved toxin is mainly used in industrial fields and proved to possess various toxicities. In recent years, AC has been found in starch-containing foods due to Maillard reaction in a high-temperature process. Therefore, how to mitigate the toxic effect of AC is a research spot. Blumea laciniata is a widely used folk medicine in Asia and the extract from B. laciniata (EBL) exhibited a strong protection on cells against oxidative stress. In this work, we used EBL to protect Hep G2 cells and Caenorhabditis elegans against AC toxicity. As the results turned out, EBL increased cell viability under AC stress and notably reduced the cell apoptosis through decreasing the high level of ROS. Moreover, EBL extended the survival time of C. elegans, while EBL failed to prolong the survival time of mutants that were in Insulin signaling pathway. Besides, the expressions of antioxidant enzymes were activated after the worms were treated with EBL and daf-16 gene was activated. Our results indicated that EBL exhibited a protective effect against AC induced toxicity in Hep G2 cells and C. elegans via Insulin/IGF-1 signaling pathway. These outcomes may provide a promising natural drug to alleviate the toxic effect of AC.
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Affiliation(s)
- Lijun Zhou
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Siyuan Luo
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Xiaoju Wang
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Yiling Zhou
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Yuan Zhang
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Shuai Zhu
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Tao Chen
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Shiling Feng
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Ming Yuan
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
| | - Chunbang Ding
- College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
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Sub-nanowatt resolution direct calorimetry for probing real-time metabolic activity of individual C. elegans worms. Nat Commun 2020; 11:2983. [PMID: 32532993 PMCID: PMC7293274 DOI: 10.1038/s41467-020-16690-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 05/13/2020] [Indexed: 11/25/2022] Open
Abstract
Calorimetry has been widely used in metabolic studies, but direct measurements from individual small biological model organisms such as C. elegans or isolated single cells have been limited by poor sensitivity of existing techniques and difficulties in resolving very small heat outputs. Here, by careful thermal engineering, we developed a robust, highly sensitive and bio-compatible calorimetric platform that features a resolution of ~270 pW—more than a 500-fold improvement over the most sensitive calorimeter previously used for measuring the metabolic heat output of C. elegans. Using this calorimeter, we demonstrate time-resolved metabolic measurements of single C. elegans worms from larval to adult stages. Further, we show that the metabolic output is significantly lower in long-lived C. elegans daf-2 mutants. These demonstrations clearly highlight the broad potential of this tool for studying the role of metabolism in disease, development and aging of small model organisms and single cells. Calorimetry is widely used for metabolic studies, but measurements of single cells and small organisms are limited by the sensitivity of current techniques. Here the authors develop a sensitive platform for performing time-resolved metabolic measurements of single C. elegans worms from larval to adult stages.
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DAF-16/FoxO in Caenorhabditis elegans and Its Role in Metabolic Remodeling. Cells 2020; 9:cells9010109. [PMID: 31906434 PMCID: PMC7017163 DOI: 10.3390/cells9010109] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/30/2019] [Accepted: 12/31/2019] [Indexed: 12/31/2022] Open
Abstract
DAF-16, the only forkhead box transcription factors class O (FoxO) homolog in Caenorhabditis elegans, integrates signals from upstream pathways to elicit transcriptional changes in many genes involved in aging, development, stress, metabolism, and immunity. The major regulator of DAF-16 activity is the insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) pathway, reduction of which leads to lifespan extension in worms, flies, mice, and humans. In C. elegans daf-2 mutants, reduced IIS leads to a heterochronic activation of a dauer survival program during adulthood. This program includes elevated antioxidant defense and a metabolic shift toward accumulation of carbohydrates (i.e., trehalose and glycogen) and triglycerides, and activation of the glyoxylate shunt, which could allow fat-to-carbohydrate conversion. The longevity of daf-2 mutants seems to be partially supported by endogenous trehalose, a nonreducing disaccharide that mammals cannot synthesize, which points toward considerable differences in downstream mechanisms by which IIS regulates aging in distinct groups.
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Yanase S, Ishii T, Yasuda K, Ishii N. Metabolic Biomarkers in Nematode C. elegans During Aging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1134:163-175. [PMID: 30919337 DOI: 10.1007/978-3-030-12668-1_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Changes in energy metabolism occur not only in diseases such as cancer but also in the normal development and aging processes of various organisms. These metabolic changes result to lead to imbalances in energy metabolism related to cellular and tissue homeostasis. In the model organism C. elegans, which is used to study aging, an imbalance in age-related energy metabolism exists between mitochondrial oxidative phosphorylation and aerobic glycolysis. Cellular lactate and pyruvate are key intermediates in intracellular energy metabolic pathways and can indicate age-related imbalances in energy metabolism. Thus, the cellular lactate/pyruvate ratio can be monitored as a biomarker during aging. Moreover, recent studies have proposed a candidate novel biomarker for aging and age-related declines in the nematode C. elegans.
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Affiliation(s)
- Sumino Yanase
- Department of Health Science, Daito Bunka University School of Sports & Health Science, Higashi-matsuyama, Saitama, Japan. .,Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
| | - Takamasa Ishii
- Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Kayo Yasuda
- Department of Health Management, Undergraduate School of Health Studies, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Naoaki Ishii
- Department of Health Management, Undergraduate School of Health Studies, Tokai University, Hiratsuka, Kanagawa, Japan
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Huang HW, Lin YH, Lin MH, Huang YR, Chou CH, Hong HC, Wang MR, Tseng YT, Liao PC, Chung MC, Ma YJ, Wu SC, Chuang YJ, Wang HD, Wang YM, Huang HD, Lu TT, Liaw WF. Extension of C. elegans lifespan using the ·NO-delivery dinitrosyl iron complexes. J Biol Inorg Chem 2018; 23:775-784. [DOI: 10.1007/s00775-018-1569-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 05/18/2018] [Indexed: 12/12/2022]
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8
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Braeckman BP, Dhondt I. Lifespan extension in Caenorhabditis elegans insulin/IGF-1 signalling mutants is supported by non-vertebrate physiological traits. NEMATOLOGY 2017. [DOI: 10.1163/15685411-00003060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The insulin/IGF-1 signalling (IIS) pathway connects nutrient levels to metabolism, growth and lifespan in eukaryotes ranging from yeasts to humans, including nematodes such as the genetic model organismCaenorhabditis elegans. The link between ageing and the IIS pathway has been thoroughly studied inC. elegans; upon reduced IIS signalling, a genetic survival program is activated resulting in a drastic lifespan extension. One of the components of this program is the upregulation of antioxidant activity but experiments failed to show a clear causal relation to longevity. However, oxidative damage, such as protein carbonyls, accumulates at a slower pace in long-livedC. elegansmutants with reduced IIS. This is probably not achieved by increased macroautophagy, a process that sequesters cellular components to be eliminated as protein turnover rates are slowed down in IIS mutants. The IIS mutantdaf-2, bearing a mutation in the insulin/IGF-1 receptor, recapitulates the dauer survival program, including accumulation of fat and glycogen. Fat can be converted into glucose and glycogenviathe glyoxylate shunt, a pathway absent in vertebrates. These carbohydrates can be used as substrates for trehalose synthesis, also absent in mammals. Trehalose, a non-reducing homodimer of glucose, stabilises intracellular components and is responsible for almost half of the lifespan extension in IIS mutants. Hence, the molecular mechanisms by which lifespan is extended under reduced IIS may differ substantially between phyla that have an active glyoxylate cycle and trehalose synthesis, such as ecdysozoans and fungi, and vertebrate species such as mammals.
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Affiliation(s)
- Bart P. Braeckman
- Biology Department, Ghent University, Proeftuinstraat 86 N1, Ghent, Belgium
| | - Ineke Dhondt
- Biology Department, Ghent University, Proeftuinstraat 86 N1, Ghent, Belgium
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9
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10
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Identification of a previously undetected metabolic defect in the Complex II Caenorhabditis elegans mev-1 mutant strain using respiratory control analysis. Biogerontology 2016; 18:189-200. [PMID: 28039571 DOI: 10.1007/s10522-016-9672-6] [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] [Received: 08/06/2016] [Accepted: 12/03/2016] [Indexed: 12/18/2022]
Abstract
Hypometabolism may play an important role in the pathogenesis of ageing and ageing-related diseases. The nematode Caenorhabditis elegans offers the opportunity to study "living mitochondria" in a small (~1 mm) animal replete with a highly stereotypical, yet complex, anatomy and physiology. Basal oxygen consumption rate is often employed as a proxy for energy metabolism in this context. This parameter is traditionally measured using single-chamber Clark electrodes without the addition of metabolic modulators. Recently, multi-well oxygen electrodes, facilitating addition of metabolic modulators and hence study of respiratory control during different mitochondrial respiration states, have been developed. However, only limited official protocols exist for C. elegans, and key limitations of these techniques are therefore unclear. Following modification and testing of some of the existing protocols, we used these methods to explore mitochondrial bioenergetics in live nematodes of an electron transfer chain Complex II mutant strain, mev-1, and identified a previously undetected metabolic defect. We find that mev-1 mutants cannot respond adequately to increased energy demands, suggesting that oxidative phosphorylation is more severely impaired in these animals than has previously been appreciated.
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11
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Yen CA, Curran SP. Gene-diet interactions and aging in C. elegans. Exp Gerontol 2016; 86:106-112. [PMID: 26924670 DOI: 10.1016/j.exger.2016.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/16/2016] [Accepted: 02/24/2016] [Indexed: 02/06/2023]
Abstract
Diet is the most variable aspect of life history, as most individuals have a large diversity of food choices, varying in the type and amount that they ingest. In the short-term, diet can affect metabolism and energy levels. However, in the long run, the net deficiency or excess of calories from diet can influence the progression and severity of age-related diseases. An old and yet still debated question is: how do specific dietary choices impact health- and lifespan? It is clear that genetics can play a critical role - perhaps just as important as diet choices. For example, poor diet in combination with genetic susceptibility can lead to metabolic disorders, such as obesity and type 2 diabetes. Recent work in Caenorhabditis elegans has identified the existence of diet-gene pairs, where the consequence of mutating a specific gene is only realized on specific diets. Many core metabolic pathways are conserved from worm to human. Although only a handful of these diet-gene pairs has been characterized, there are potentially hundreds, if not thousands, of such interactions, which may explain the variability in the rates of aging in humans and the incidence and severity of age-related diseases.
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Affiliation(s)
- Chia An Yen
- University of Southern California, Dornsife College of Letters, Arts, and Science, Department of Molecular and Computational Biology, United States
| | - Sean P Curran
- University of Southern California, Dornsife College of Letters, Arts, and Science, Department of Molecular and Computational Biology, United States; University of Southern California, Davis School of Gerontology, United States.
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12
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Morsci NS, Hall DH, Driscoll M, Sheng ZH. Age-Related Phasic Patterns of Mitochondrial Maintenance in Adult Caenorhabditis elegans Neurons. J Neurosci 2016; 36:1373-85. [PMID: 26818523 PMCID: PMC4728731 DOI: 10.1523/jneurosci.2799-15.2016] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 12/11/2015] [Accepted: 12/18/2015] [Indexed: 12/22/2022] Open
Abstract
Aging is associated with cognitive decline and increasing risk of neurodegeneration. Perturbation of mitochondrial function, dynamics, and trafficking are implicated in the pathogenesis of several age-associated neurodegenerative diseases. Despite this fundamental importance, the critical understanding of how organismal aging affects lifetime neuronal mitochondrial maintenance remains unknown, particularly in a physiologically relevant context. To address this issue, we performed a comprehensive in vivo analysis of age-associated changes in mitochondrial morphology, density, trafficking, and stress resistance in individual Caenorhabditis elegans neurons throughout adult life. Adult neurons display three distinct stages of increase, maintenance, and decrease in mitochondrial size and density during adulthood. Mitochondrial trafficking in the distal neuronal processes declines progressively with age starting from early adulthood. In contrast, long-lived daf-2 mutants exhibit delayed age-associated changes in mitochondrial morphology, constant mitochondrial density, and maintained trafficking rates during adulthood. Reduced mitochondrial load at late adulthood correlates with decreased mitochondrial resistance to oxidative stress. Revealing aging-associated changes in neuronal mitochondria in vivo is an essential precedent that will allow future elucidation of the mechanistic causes of mitochondrial aging. Thus, our study establishes the critical foundation for the future analysis of cellular pathways and genetic and pharmacological factors regulating mitochondrial maintenance in aging- and disease-relevant conditions. SIGNIFICANCE STATEMENT Using Caenorhabditis elegans as a model, we address long-standing questions: How does aging affect neuronal mitochondrial morphology, density, trafficking, and oxidative stress resistance? Are these age-related changes amenable to genetic manipulations that slow down the aging process? Our study illustrates that mitochondrial trafficking declines progressively from the first day of adulthood, whereas mitochondrial size, density, and resistance to oxidative stress undergo three distinct stages: increase in early adulthood, maintenance at high levels during mid-adulthood, and decline during late adulthood. Thus, our study characterizes mitochondrial aging profile at the level of a single neuron in its native environment and establishes the critical foundation for the future genetic and pharmacological dissection of factors that influence long-term mitochondrial maintenance in neurons.
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Affiliation(s)
- Natalia S Morsci
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
| | - David H Hall
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, and
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08855
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892,
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Glycogen Fuels Survival During Hyposmotic-Anoxic Stress in Caenorhabditis elegans. Genetics 2015; 201:65-74. [PMID: 26116152 PMCID: PMC4566277 DOI: 10.1534/genetics.115.179416] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/18/2015] [Indexed: 11/18/2022] Open
Abstract
Oxygen is an absolute requirement for multicellular life. Animals that are deprived of oxygen for sufficient periods of time eventually become injured and die. This is largely due to the fact that, without oxygen, animals are unable to generate sufficient quantities of energy. In human diseases triggered by oxygen deprivation, such as heart attack and stroke, hyposmotic stress and cell swelling (edema) arise in affected tissues as a direct result of energetic failure. Edema independently enhances tissue injury in these diseases by incompletely understood mechanisms, resulting in poor clinical outcomes. Here, we present investigations into the effects of osmotic stress during complete oxygen deprivation (anoxia) in the genetically tractable nematode Caenorhabditis elegans. Our findings demonstrate that nematode survival of a hyposmotic environment during anoxia (hyposmotic anoxia) depends on the nematode’s ability to engage in glycogen metabolism. We also present results of a genome-wide screen for genes affecting glycogen content and localization in the nematode, showing that nematode survival of hyposmotic anoxia depends on a large number of these genes. Finally, we show that an inability to engage in glycogen synthesis results in suppression of the enhanced survival phenotype observed in daf-2 insulin-like pathway mutants, suggesting that alterations in glycogen metabolism may serve as a basis for these mutants’ resistance to hyposmotic anoxia.
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Lourenço AB, Muñoz-Jiménez C, Venegas-Calerón M, Artal-Sanz M. Analysis of the effect of the mitochondrial prohibitin complex, a context-dependent modulator of longevity, on the C. elegans metabolome. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1457-68. [PMID: 26092086 PMCID: PMC4580209 DOI: 10.1016/j.bbabio.2015.06.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 05/11/2015] [Accepted: 06/03/2015] [Indexed: 11/25/2022]
Abstract
The mitochondrial prohibitin complex, composed of two proteins, PHB-1 and PHB-2, is a context-dependent modulator of longevity. Specifically, prohibitin deficiency shortens the lifespan of otherwise wild type worms, while it dramatically extends the lifespan under compromised metabolic conditions. This extremely intriguingly phenotype has been linked to alterations in mitochondrial function and in fat metabolism. However, the true function of the mitochondrial prohibitin complex remains elusive. Here, we used gas chromatography coupled to a flame ionization detector (GC/FID) and 1H NMR spectroscopy to gain molecular insights into the effect of prohibitin depletion on the Caenorhabditis elegans metabolome. We analysed the effect of prohibitin deficiency in two different developmental stages and under two different conditions, which result in opposing longevity phenotypes, namely wild type worms and daf-2(e1370) insulin signalling deficient mutants. Prohibitin depletion was shown to alter the fatty acid (GC/FID) and 1H NMR metabolic profiles of wild type animals both at the fourth larval stage of development (L4) and at the young adult (YA) stage, while being more pronounced at the later stage. Furthermore, wild type and the diapause mutant daf-2(e1370), either expressing or not prohibitin, were clearly distinguishable based on their metabolic profiles, revealing changes in fatty acid composition, as well as in carbohydrate and amino acid metabolism. Moreover, the metabolic data indicate that daf-2(e1370) mutants are more robust than the wild type animals to changes induced by prohibitin depletion. The impact of prohibitin depletion on the C. elegans metabolome will be discussed herein in the scope of its effect on longevity. This article is part of a Special Issue entitled: Mitochondrial Dysfunction in Aging. Guest Editor: Aleksandra Trifunovic Impact of the mitochondrial prohibitin (PHB) complex on the C. elegans metabolome Depletion of individual PHB subunits results in similar metabolic profiles. PHB affects fatty acid composition, amino acid and carbohydrate metabolism. daf-2 mutants are more robust than wild type worms to the effect of PHB depletion. Modulation of fermentation may contribute to the longevity of PHB-depleted worms.
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Affiliation(s)
- Artur B Lourenço
- Andalusian Centre for Developmental Biology (CABD), CSIC, Universidad Pablo de Olavide-Junta de Andalucía, Carretera de Utrera, km 1, 41013 Sevilla, Spain
| | - Celia Muñoz-Jiménez
- Andalusian Centre for Developmental Biology (CABD), CSIC, Universidad Pablo de Olavide-Junta de Andalucía, Carretera de Utrera, km 1, 41013 Sevilla, Spain
| | - Mónica Venegas-Calerón
- Department of Biochemistry and Molecular Biology of Plant Products, Instituto de la Grasa (IG-CSIC), Ctra. Utrera Km 1, Campus Universitario Pablo de Olavide, 41013, Sevilla, Spain
| | - Marta Artal-Sanz
- Andalusian Centre for Developmental Biology (CABD), CSIC, Universidad Pablo de Olavide-Junta de Andalucía, Carretera de Utrera, km 1, 41013 Sevilla, Spain.
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Song S, Zhang X, Wu H, Han Y, Zhang J, Ma E, Guo Y. Molecular basis for antioxidant enzymes in mediating copper detoxification in the nematode Caenorhabditis elegans. PLoS One 2014; 9:e107685. [PMID: 25243607 PMCID: PMC4171499 DOI: 10.1371/journal.pone.0107685] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 08/15/2014] [Indexed: 11/21/2022] Open
Abstract
Antioxidant enzymes play a major role in defending against oxidative damage by copper. However, few studies have been performed to determine which antioxidant enzymes respond to and are necessary for copper detoxification. In this study, we examined both the activities and mRNA levels of SOD, CAT, and GPX under excessive copper stress in Caenorhabditis elegans, which is a powerful model for toxicity studies. Then, taking advantage of the genetics of this model, we assessed the lethal concentration (LC50) values of copper for related mutant strains. The results showed that the SOD, CAT, and GPX activities were significantly greater in treated groups than in controls. The mRNA levels of sod-3, sod-5, ctl-1, ctl-2, and almost all gpx genes were also significantly greater in treated groups than in controls. Among tested mutants, the sod-5, ctl-1, gpx-3, gpx-4, and gpx-6 variants exhibited hypersensitivity to copper. The strains with SOD or CAT over expression were reduced sensitive to copper. Mutations in daf-2 and age-1, which are involved in the insulin/insulin-like growth factor-1 signaling pathway, result in reduced sensitivity to stress. Here, we showed that LC50 values for copper in daf-2 and age-1 mutants were significantly greater than in N2 worms. However, the LC50 values in daf-16;daf-2 and daf-16;age-1 mutants were significantly reduced than in daf-2 and age-1 mutants, implying that reduced copper sensitivity is influenced by DAF-16-related functioning. SOD, CAT, and GPX activities and the mRNA levels of the associated copper responsive genes were significantly increased in daf-2 and age-1 mutants compared to N2. Additionally, the activities of SOD, CAT, and GPX were greater in these mutants than in N2 when treated with copper. Our results not only support the theory that antioxidant enzymes play an important role in copper detoxification but also identify the response and the genes involved in these processes.
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Affiliation(s)
- Shaojuan Song
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Xueyao Zhang
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Haihua Wu
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Yan Han
- School of Life Science, Shanxi University, Taiyuan, Shanxi, China
| | - Jianzhen Zhang
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Enbo Ma
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Yaping Guo
- School of Life Science, Shanxi University, Taiyuan, Shanxi, China
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Ristow M, Schmeisser K. Mitohormesis: Promoting Health and Lifespan by Increased Levels of Reactive Oxygen Species (ROS). Dose Response 2014; 12:288-341. [PMID: 24910588 PMCID: PMC4036400 DOI: 10.2203/dose-response.13-035.ristow] [Citation(s) in RCA: 314] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Increasing evidence indicates that reactive oxygen species (ROS), consisting of superoxide, hydrogen peroxide, and multiple others, do not only cause oxidative stress, but rather may function as signaling molecules that promote health by preventing or delaying a number of chronic diseases, and ultimately extend lifespan. While high levels of ROS are generally accepted to cause cellular damage and to promote aging, low levels of these may rather improve systemic defense mechanisms by inducing an adaptive response. This concept has been named mitochondrial hormesis or mitohormesis. We here evaluate and summarize more than 500 publications from current literature regarding such ROS-mediated low-dose signaling events, including calorie restriction, hypoxia, temperature stress, and physical activity, as well as signaling events downstream of insulin/IGF-1 receptors, AMP-dependent kinase (AMPK), target-of-rapamycin (TOR), and lastly sirtuins to culminate in control of proteostasis, unfolded protein response (UPR), stem cell maintenance and stress resistance. Additionally, consequences of interfering with such ROS signals by pharmacological or natural compounds are being discussed, concluding that particularly antioxidants are useless or even harmful.
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Affiliation(s)
- Michael Ristow
- Energy Metabolism Laboratory, ETH Zürich (Swiss Federal Institute of Technology Zurich), Schwerzenbach/Zürich, CH 8603, Switzerland
- Dept. of Human Nutrition, Institute of Nutrition, University of Jena, Jena D-07743, Germany
| | - Kathrin Schmeisser
- Dept. of Human Nutrition, Institute of Nutrition, University of Jena, Jena D-07743, Germany
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Fernandes de Abreu DA, Caballero A, Fardel P, Stroustrup N, Chen Z, Lee K, Keyes WD, Nash ZM, López-Moyado IF, Vaggi F, Cornils A, Regenass M, Neagu A, Ostojic I, Liu C, Cho Y, Sifoglu D, Shen Y, Fontana W, Lu H, Csikasz-Nagy A, Murphy CT, Antebi A, Blanc E, Apfeld J, Zhang Y, Alcedo J, Ch'ng Q. An insulin-to-insulin regulatory network orchestrates phenotypic specificity in development and physiology. PLoS Genet 2014; 10:e1004225. [PMID: 24675767 PMCID: PMC3967928 DOI: 10.1371/journal.pgen.1004225] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 01/22/2014] [Indexed: 12/22/2022] Open
Abstract
Insulin-like peptides (ILPs) play highly conserved roles in development and physiology. Most animal genomes encode multiple ILPs. Here we identify mechanisms for how the forty Caenorhabditis elegans ILPs coordinate diverse processes, including development, reproduction, longevity and several specific stress responses. Our systematic studies identify an ILP-based combinatorial code for these phenotypes characterized by substantial functional specificity and diversity rather than global redundancy. Notably, we show that ILPs regulate each other transcriptionally, uncovering an ILP-to-ILP regulatory network that underlies the combinatorial phenotypic coding by the ILP family. Extensive analyses of genetic interactions among ILPs reveal how their signals are integrated. A combined analysis of these functional and regulatory ILP interactions identifies local genetic circuits that act in parallel and interact by crosstalk, feedback and compensation. This organization provides emergent mechanisms for phenotypic specificity and graded regulation for the combinatorial phenotypic coding we observe. Our findings also provide insights into how large hormonal networks regulate diverse traits.
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Affiliation(s)
| | - Antonio Caballero
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Pascal Fardel
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Biozentrum, University of Basel, Basel, Basel, Switzerland
| | - Nicholas Stroustrup
- Dept of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Zhunan Chen
- Dept of Organismic and Evolutionary Biology, The Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - KyungHwa Lee
- Lewis-Sigler Institute for Integrative Genomics and Dept of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - William D. Keyes
- Lewis-Sigler Institute for Integrative Genomics and Dept of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Zachary M. Nash
- Dept of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Isaac F. López-Moyado
- Dept of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Federico Vaggi
- Research and Innovation Center, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Astrid Cornils
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Martin Regenass
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Anca Neagu
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Biozentrum, University of Basel, Basel, Basel, Switzerland
| | - Ivan Ostojic
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Chang Liu
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Yongmin Cho
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Deniz Sifoglu
- Dept of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - Yu Shen
- Dept of Organismic and Evolutionary Biology, The Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Walter Fontana
- Dept of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hang Lu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Attila Csikasz-Nagy
- Research and Innovation Center, Fondazione Edmund Mach, San Michele all'Adige, Italy
- Institute for Mathematical and Molecular Biomedicine, King's College London, London, United Kingdom
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Coleen T. Murphy
- Lewis-Sigler Institute for Integrative Genomics and Dept of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Adam Antebi
- Max Planck Institute for Biology of Ageing, Koeln, Germany
| | - Eric Blanc
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Javier Apfeld
- Dept of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yun Zhang
- Dept of Organismic and Evolutionary Biology, The Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Joy Alcedo
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Dept of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - QueeLim Ch'ng
- MRC Centre for Developmental Neurobiology, King's College London, London, United Kingdom
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18
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Iranon NN, Miller DL. Interactions between oxygen homeostasis, food availability, and hydrogen sulfide signaling. Front Genet 2012; 3:257. [PMID: 23233860 PMCID: PMC3516179 DOI: 10.3389/fgene.2012.00257] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/04/2012] [Indexed: 12/19/2022] Open
Abstract
The ability to sense and respond to stressful conditions is essential to maintain organismal homeostasis. It has long been recognized that stress response factors that improve survival in changing conditions can also influence longevity. In this review, we discuss different strategies used by animals in response to decreased O(2) (hypoxia) to maintain O(2) homeostasis, and consider interactions between hypoxia responses, nutritional status, and H(2)S signaling. O(2) is an essential environmental nutrient for almost all metazoans as it plays a fundamental role in development and cellular metabolism. However, the physiological response(s) to hypoxia depend greatly on the amount of O(2) available. Animals must sense declining O(2) availability to coordinate fundamental metabolic and signaling pathways. It is not surprising that factors involved in the response to hypoxia are also involved in responding to other key environmental signals, particularly food availability. Recent studies in mammals have also shown that the small gaseous signaling molecule hydrogen sulfide (H(2)S) protects against cellular damage and death in hypoxia. These results suggest that H(2)S signaling also integrates with hypoxia response(s). Many of the signaling pathways that mediate the effects of hypoxia, food deprivation, and H(2)S signaling have also been implicated in the control of lifespan. Understanding how these pathways are coordinated therefore has the potential to reveal new cellular and organismal homeostatic mechanisms that contribute to longevity assurance in animals.
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Affiliation(s)
- Nicole N Iranon
- Department of Biochemistry, University of Washington School of Medicine Seattle, WA, USA ; Molecular and Cellular Biology Graduate Program, University of Washington School of Medicine Seattle, WA, USA
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Kim Y, Sun H. ASM-3 acid sphingomyelinase functions as a positive regulator of the DAF-2/AGE-1 signaling pathway and serves as a novel anti-aging target. PLoS One 2012; 7:e45890. [PMID: 23049887 PMCID: PMC3457945 DOI: 10.1371/journal.pone.0045890] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 08/27/2012] [Indexed: 02/05/2023] Open
Abstract
In C. elegans, the highly conserved DAF-2/insulin/insulin-like growth factor 1 receptor signaling (IIS) pathway regulates longevity, metabolism, reproduction and development. In mammals, acid sphingomyelinase (ASM) is an enzyme that hydrolyzes sphingomyelin to produce ceramide. ASM has been implicated in CD95 death receptor signaling under certain stress conditions. However, the involvement of ASM in growth factor receptor signaling under physiological conditions is not known. Here, we report that in vivo ASM functions as a positive regulator of the DAF-2/IIS pathway in C. elegans. We have shown that inactivation of asm-3 extends animal lifespan and promotes dauer arrest, an alternative developmental process. A significant cooperative effect on lifespan is observed between asm-3 deficiency and loss-of-function alleles of the age-1/PI 3-kinase, with the asm-3; age-1 double mutant animals having a mean lifespan 259% greater than that of the wild-type animals. The lifespan extension phenotypes caused by the loss of asm-3 are dependent on the functions of daf-16/FOXO and daf-18/PTEN. We have demonstrated that inactivation of asm-3 causes nuclear translocation of DAF-16::GFP protein, up-regulates endogenous DAF-16 protein levels and activates the downstream targeting genes of DAF-16. Together, our findings reveal a novel role of asm-3 in regulation of lifespan and diapause by modulating IIS pathway. Importantly, we have found that two drugs known to inhibit mammalian ASM activities, desipramine and clomipramine, markedly extend the lifespan of wild-type animals, in a manner similar to that achieved by genetic inactivation of the asm genes. Our studies illustrate a novel strategy of anti-aging by targeting ASM, which may potentially be extended to mammals.
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Affiliation(s)
- Yongsoon Kim
- Laboratory of Cancer Genomics, Nevada Cancer Institute, Las Vegas, Nevada, United States of America
- Department of Chemistry, University of Nevada, Las Vegas, Las Vegas, Nevada, United States of America
- * E-mail: (YK); (HS)
| | - Hong Sun
- Laboratory of Cancer Genomics, Nevada Cancer Institute, Las Vegas, Nevada, United States of America
- Department of Chemistry, University of Nevada, Las Vegas, Las Vegas, Nevada, United States of America
- * E-mail: (YK); (HS)
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20
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Zarse K, Schmeisser S, Groth M, Priebe S, Beuster G, Kuhlow D, Guthke R, Platzer M, Kahn CR, Ristow M. Impaired insulin/IGF1 signaling extends life span by promoting mitochondrial L-proline catabolism to induce a transient ROS signal. Cell Metab 2012; 15:451-65. [PMID: 22482728 PMCID: PMC4844853 DOI: 10.1016/j.cmet.2012.02.013] [Citation(s) in RCA: 331] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 02/01/2012] [Accepted: 02/23/2012] [Indexed: 01/14/2023]
Abstract
Impaired insulin and IGF-1 signaling (iIIS) in C. elegans daf-2 mutants extends life span more than 2-fold. Constitutively, iIIS increases mitochondrial activity and reduces reactive oxygen species (ROS) levels. By contrast, acute impairment of daf-2 in adult C. elegans reduces glucose uptake and transiently increases ROS. Consistent with the concept of mitohormesis, this ROS signal causes an adaptive response by inducing ROS defense enzymes (SOD, catalase), culminating in ultimately reduced ROS levels despite increased mitochondrial activity. Inhibition of this ROS signal by antioxidants reduces iIIS-mediated longevity by up to 60%. Induction of the ROS signal requires AAK-2 (AMPK), while PMK-1 (p38) and SKN-1 (NRF-2) are needed for the retrograde response. IIIS upregulates mitochondrial L-proline catabolism, and impairment of the latter impairs the life span-extending capacity of iIIS while L-proline supplementation extends C. elegans life span. Taken together, iIIS promotes L-proline metabolism to generate a ROS signal for the adaptive induction of endogenous stress defense to extend life span.
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Affiliation(s)
- Kim Zarse
- Department of Human Nutrition, Institute of Nutrition, University of Jena, Jena, Germany
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21
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Ristow M, Schmeisser S. Extending life span by increasing oxidative stress. Free Radic Biol Med 2011; 51:327-36. [PMID: 21619928 DOI: 10.1016/j.freeradbiomed.2011.05.010] [Citation(s) in RCA: 509] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 05/08/2011] [Accepted: 05/09/2011] [Indexed: 12/31/2022]
Abstract
Various nutritional, behavioral, and pharmacological interventions have been previously shown to extend life span in diverse model organisms, including Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mice, and rats, as well as possibly monkeys and humans. This review aims to summarize published evidence that several longevity-promoting interventions may converge by causing an activation of mitochondrial oxygen consumption to promote increased formation of reactive oxygen species (ROS). These serve as molecular signals to exert downstream effects to ultimately induce endogenous defense mechanisms culminating in increased stress resistance and longevity, an adaptive response more specifically named mitochondrial hormesis or mitohormesis. Consistently, we here summarize findings that antioxidant supplements that prevent these ROS signals interfere with the health-promoting and life-span-extending capabilities of calorie restriction and physical exercise. Taken together and consistent with ample published evidence, the findings summarized here question Harman's Free Radical Theory of Aging and rather suggest that ROS act as essential signaling molecules to promote metabolic health and longevity.
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Affiliation(s)
- Michael Ristow
- Department of Human Nutrition, Institute of Nutrition, University of Jena, D-07743 Jena, Germany.
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22
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Schaffer S, Gruber J, Ng LF, Fong S, Wong YT, Tang SY, Halliwell B. The effect of dichloroacetate on health- and lifespan in C. elegans. Biogerontology 2010; 12:195-209. [PMID: 21153705 DOI: 10.1007/s10522-010-9310-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 11/29/2010] [Indexed: 12/14/2022]
Abstract
Aging is associated with increased vulnerability to chronic, degenerative diseases and death. Strategies for promoting healthspan without necessarily affecting lifespan or aging rate have gained much interest. The mitochondrial free radical theory of aging suggests that mitochondria and, in particular, age-dependent mitochondrial decline play a central role in aging, making compounds that affect mitochondrial function a possible strategy for the modulation of healthspan and possibly the aging rate. Here we tested such a "metabolic tuning" approach in nematodes using the mitochondrial modulator dichloroacetate (DCA). We explored DCA as a proof-of-principle compound to alter mitochondrial parameters in wild-type animals and tested whether this approach is suitable for reducing reactive oxygen species (ROS) production and for improving organismal health- and lifespan. In parallel, we addressed the potential problem of operator bias by running both unblinded and blinded lifespan studies. We found that DCA treatment (1) increased ATP levels without elevating oxidative protein damage and (2) reduced ROS production in adult C. elegans. DCA treatment also significantly prolonged nematode health- and lifespan, but did not strongly impact mortality doubling time. Operator blinding resulted in considerably smaller lifespan-extending effects of DCA. Our data illustrate the promise of a "metabolic tuning" intervention strategy, emphasize the importance of mitochondria in nematode aging and highlight operator bias as a potential confounder in lifespan studies.
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Affiliation(s)
- S Schaffer
- Department of Biochemistry, Centre for Life Sciences, National University of Singapore, Singapore.
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23
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Kim J, Shirasawa T, Miyamoto Y. The effect of TAT conjugated platinum nanoparticles on lifespan in a nematode Caenorhabditis elegans model. Biomaterials 2010; 31:5849-54. [DOI: 10.1016/j.biomaterials.2010.03.077] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 03/30/2010] [Indexed: 11/26/2022]
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Brys K, Castelein N, Matthijssens F, Vanfleteren JR, Braeckman BP. Disruption of insulin signalling preserves bioenergetic competence of mitochondria in ageing Caenorhabditis elegans. BMC Biol 2010; 8:91. [PMID: 20584279 PMCID: PMC2914644 DOI: 10.1186/1741-7007-8-91] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 06/28/2010] [Indexed: 11/30/2022] Open
Abstract
Background The gene daf-2 encodes the single insulin/insulin growth factor-1-like receptor of Caenorhabditis elegans. The reduction-of-function allele e1370 induces several metabolic alterations and doubles lifespan. Results We found that the e1370 mutation alters aerobic energy production substantially. In wild-type worms the abundance of key mitochondrial proteins declines with age, accompanied by a dramatic decrease in energy production, although the mitochondrial mass, inferred from the mitochondrial DNA copy number, remains unaltered. In contrast, the age-dependent decrease of both key mitochondrial proteins and bioenergetic competence is considerably attenuated in daf-2(e1370) adult animals. The increase in daf-2(e1370) mitochondrial competence is associated with a higher membrane potential and increased reactive oxygen species production, but with little damage to mitochondrial protein or DNA. Together these results point to a higher energetic efficiency of daf-2(e1370) animals. Conclusions We conclude that low daf-2 function alters the overall rate of ageing by a yet unidentified mechanism with an indirect protective effect on mitochondrial function.
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Affiliation(s)
- Kristel Brys
- Department of Biology, Ghent University, K L Ledeganckstraat 35, Ghent B-9000, Belgium.
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25
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How increased oxidative stress promotes longevity and metabolic health: The concept of mitochondrial hormesis (mitohormesis). Exp Gerontol 2010; 45:410-8. [PMID: 20350594 DOI: 10.1016/j.exger.2010.03.014] [Citation(s) in RCA: 531] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 03/09/2010] [Accepted: 03/19/2010] [Indexed: 12/23/2022]
Abstract
Recent evidence suggests that calorie restriction and specifically reduced glucose metabolism induces mitochondrial metabolism to extend life span in various model organisms, including Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans and possibly mice. In conflict with Harman's free radical theory of aging (FRTA), these effects may be due to increased formation of reactive oxygen species (ROS) within the mitochondria causing an adaptive response that culminates in subsequently increased stress resistance assumed to ultimately cause a long-term reduction of oxidative stress. This type of retrograde response has been named mitochondrial hormesis or mitohormesis, and may in addition be applicable to the health-promoting effects of physical exercise in humans and, hypothetically, impaired insulin/IGF-1-signaling in model organisms. Consistently, abrogation of this mitochondrial ROS signal by antioxidants impairs the lifespan-extending and health-promoting capabilities of glucose restriction and physical exercise, respectively. In summary, the findings discussed in this review indicate that ROS are essential signaling molecules which are required to promote health and longevity. Hence, the concept of mitohormesis provides a common mechanistic denominator for the physiological effects of physical exercise, reduced calorie uptake, glucose restriction, and possibly beyond.
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26
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Back P, Matthijssens F, Vlaeminck C, Braeckman BP, Vanfleteren JR. Effects of sod gene overexpression and deletion mutation on the expression profiles of reporter genes of major detoxification pathways in Caenorhabditis elegans. Exp Gerontol 2010; 45:603-10. [PMID: 20096764 DOI: 10.1016/j.exger.2010.01.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 12/23/2009] [Accepted: 01/14/2010] [Indexed: 12/17/2022]
Abstract
Reactive oxygen species have long been considered a major cause of aging. However, previous work showed that loss of superoxide dismutase (SOD) only weakly affects lifespan of Caenorhabditis elegans. Here, we examined the impact of sod gene deletion and overexpression on the mRNA levels of the remaining sod genes and other detoxification genes. We detected no compensatory upregulation of other sod genes in any of the sod deletion mutants in both wild-type and daf-2(m577) genetic backgrounds when L4 larvae were shifted from 17 to 24 degrees C, and harvested as young adults. Elimination of MnSOD increased transcription of SKN-1 regulated genes and reduced transcription of multiple DAF-16 targets. Loss of the major Cu/ZnSOD isoform SOD-1 caused enhanced expression of subsets of both SKN-1 and DAF-16 targets when the animals were grown continuously at 24 degrees C, and strong overexpression of sod-1 induced a compensatory decrease in all tested SKN-1 regulated gst genes. When combined, these results suggest that low cytosolic SOD may activate SKN-1 signaling, whereas high levels may be repressive. Overall, our results suggest that sod gene manipulation causes complex, combinatorial regulation of expression of individual targets of stress sensitive transcription factors.
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Affiliation(s)
- Patricia Back
- Laboratory for Aging Physiology and Molecular Evolution, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, Ghent, Belgium.
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27
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Frazier HN, Roth MB. Adaptive sugar provisioning controls survival of C. elegans embryos in adverse environments. Curr Biol 2009; 19:859-63. [PMID: 19398339 DOI: 10.1016/j.cub.2009.03.066] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 03/06/2009] [Accepted: 03/25/2009] [Indexed: 01/08/2023]
Abstract
The ability to adapt to changing environmental conditions is essential to the fitness of organisms. In some cases, adaptation of the parent alters the offspring's phenotype [1-10]. Such parental effects are adaptive for the offspring if the future environment is similar to the current one but can be maladaptive otherwise [11]. One mechanism by which adaptation occurs is altered provisioning of embryos by the parent [12-16]. Here we show that exposing adult Caenorhabditis elegans to hyperosmotic conditions protects their offspring from these conditions but causes sensitivity to anoxia exposure. We show that this alteration of survival is correlated with changes in the sugar content of adults and embryos. In addition, mutations in gene products that alter sugar homeostasis also alter the ability of embryos to survive in hyperosmotic and anoxic conditions and engage in the adaptive parental effect. Our results indicate that there is a physiological trade-off between the presence of glycerol, which protects animals from hyperosmotic conditions, and glycogen, which is consumed during anoxia. These two metabolites play an essential role in the survival of worms in these adverse environments, and the adaptive parental effect we describe is mediated by the provisioning of these metabolites to the embryo.
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Affiliation(s)
- Harold N Frazier
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195, USA
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28
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Schulenburg H, Kurtz J, Moret Y, Siva-Jothy MT. Introduction. Ecological immunology. Philos Trans R Soc Lond B Biol Sci 2009; 364:3-14. [PMID: 18926970 DOI: 10.1098/rstb.2008.0249] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An organism's fitness is critically reliant on its immune system to provide protection against parasites and pathogens. The structure of even simple immune systems is surprisingly complex and clearly will have been moulded by the organism's ecology. The aim of this review and the theme issue is to examine the role of different ecological factors on the evolution of immunity. Here, we will provide a general framework of the field by contextualizing the main ecological factors, including interactions with parasites, other types of biotic as well as abiotic interactions, intraspecific selective constraints (life-history trade-offs, sexual selection) and population genetic processes. We then elaborate the resulting immunological consequences such as the diversity of defence mechanisms (e.g. avoidance behaviour, resistance, tolerance), redundancy and protection against immunopathology, life-history integration of the immune response and shared immunity within a community (e.g. social immunity and microbiota-mediated protection). Our review summarizes the concepts of current importance and directs the reader to promising future research avenues that will deepen our understanding of the defence against parasites and pathogens.
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Affiliation(s)
- Hinrich Schulenburg
- Zoological Institute, University of Kiel, Am Botanischen Garten, 24098 Kiel, Germany.
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29
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Pri-Tal BM, Brown JM, Riehle MA. Identification and characterization of the catalytic subunit of phosphatidylinositol 3-kinase in the yellow fever mosquito Aedes aegypti. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2008; 38:932-939. [PMID: 18718536 DOI: 10.1016/j.ibmb.2008.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 07/22/2008] [Accepted: 07/22/2008] [Indexed: 05/26/2023]
Abstract
We characterized the catalytic subunit of phosphatidylinositol 3-kinase in Aedes aegypti (Aaegp110). Aaegp110 is an essential component of the insulin/ insulin growth factor I signaling (IIS) cascade, which regulates aging, reproduction, and other physiological processes in diverse organisms. The Aaegp110 gene encodes five putative domains (adapter binding, ras binding, C2, helical, and PI3-kinase) identified by sequence homology with other p110 proteins. Aaegp110 transcript was expressed during all A. aegypti life stages except late pupae, with particularly high levels in embryos. In female tissues, Aaegp110 transcript and protein were strongly expressed in ovaries, and moderately expressed in midguts, fat bodies and heads. The importance of IIS in mosquito reproduction led us to examine Aaegp110 ovarian expression during reproduction. Aaegp110 was expressed in ovaries prior to and during the first 24h post-bloodmeal, but undetectable 36-48 h post-bloodmeal. Following oviposition Aaegp110 protein levels returned to pre-bloodmeal levels. In reproductively arrested ovaries, Aaegp110 was present predominantly in the cytoplasm of follicle cells surrounding the oocyte. In vitro stimulation of the ovaries with 17 microM bovine insulin resulted in translocation of Aaegp110 from the cytoplasm to cell membrane in 15s. Lower concentrations (0.17 microM) also recruited Aaegp110 to the cell membrane.
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30
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Yanase S, Ishii N. Hyperoxia exposure induced hormesis decreases mitochondrial superoxide radical levels via Ins/IGF-1 signaling pathway in a long-lived age-1 mutant of Caenorhabditis elegans. JOURNAL OF RADIATION RESEARCH 2008; 49:211-218. [PMID: 18285659 DOI: 10.1269/jrr.07043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The hormetic effect, which extends the lifespan by various stressors, has been confirmed in Caenorhabditis elegans (C. elegans). We have previously reported that oxidative stress resistance in a long-lived mutant age-1 is associated with the hormesis. In the age-1 allele, which activates an insulin/insulin-like growth factor-1 (Ins/IGF-1) signaling pathway, the superoxide dismutase (SOD) and catalase activities increased during normal aging. We now demonstrate changes in the mitochondrial superoxide radical (*O(2)(-)) levels of the hormetic conditioned age-related strains. The *O(2)(-) levels in age-1 strain significantly decreased after intermittent hyperoxia exposure. On the other hand, this phenomenon was not observed in a daf-16 null mutant. This hormesis-dependent reduction of the *O(2)(-) levels was observed even if the mitochondrial Mn-SOD was experimentally reduced. Therefore, it is indicated that the hormesis is mediated by events that suppress the mitochondrial *O(2)(-) production. Moreover, some SOD gene expressions in the hormetic conditioned age-1 mutant were induced over steady state mRNA levels. These data suggest that oxidative stress-inducible hormesis is associated with a reduction of the mitochondrial *O(2)(-) production by activation of the antioxidant system via the Ins/IGF-1 signaling pathway.
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Affiliation(s)
- Sumino Yanase
- Department of Health Science, Daito Bunka University School of Sports & Health Science, Iwadono, Saitama, Japan
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31
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Lagido C, Pettitt J, Flett A, Glover LA. Bridging the phenotypic gap: real-time assessment of mitochondrial function and metabolism of the nematode Caenorhabditis elegans. BMC PHYSIOLOGY 2008; 8:7. [PMID: 18384668 PMCID: PMC2364618 DOI: 10.1186/1472-6793-8-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 04/02/2008] [Indexed: 12/21/2022]
Abstract
BACKGROUND The ATP levels of an organism are an important physiological parameter that is affected by genetic make up, ageing, stress and disease. RESULTS We have generated luminescent C. elegans through ubiquitous, constitutive expression of firefly luciferase, widely used for in vitro ATP determination. We hypothesise that whole animal luminescence reflects its intracellular ATP levels in vivo. To test this, we characterised the bioluminescence response of C. elegans during sublethal exposure to, and recovery from azide, a treatment that inhibits mitochondrial respiration reversibly, and causes ATP depletion. Consistent with our expectations, in vivo luminescence decreased with increasing sublethal azide levels, and recovered fully when worms were removed from azide. Firefly luciferase expression levels, stability and activity did not influence the final luminescence. Bioluminescence also reflected the lowered activity of the electron transport chain achieved with RNA interference (RNAi) of genes encoding respiratory chain components. CONCLUSION Results indicated that C. elegans luminescence reports on ATP levels in real-time. For the first time, we are able to directly assess the metabolism of a whole, living, multicellular organism by determination of the relative ATP levels. This will enable genetic analysis based on a readily quantifiable metabolic phenotype and will provide novel insights into mechanisms of fitness and disease that are likely to be of relevance for other organisms, as well as the worm.
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Affiliation(s)
- Cristina Lagido
- Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Jonathan Pettitt
- Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Aileen Flett
- Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - L Anne Glover
- Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Aberdeen, UK
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32
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Hoogewijs D, Houthoofd K, Matthijssens F, Vandesompele J, Vanfleteren JR. Selection and validation of a set of reliable reference genes for quantitative sod gene expression analysis in C. elegans. BMC Mol Biol 2008; 9:9. [PMID: 18211699 PMCID: PMC2254638 DOI: 10.1186/1471-2199-9-9] [Citation(s) in RCA: 289] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 01/22/2008] [Indexed: 11/10/2022] Open
Abstract
Background In the nematode Caenorhabditis elegans the conserved Ins/IGF-1 signaling pathway regulates many biological processes including life span, stress response, dauer diapause and metabolism. Detection of differentially expressed genes may contribute to a better understanding of the mechanism by which the Ins/IGF-1 signaling pathway regulates these processes. Appropriate normalization is an essential prerequisite for obtaining accurate and reproducible quantification of gene expression levels. The aim of this study was to establish a reliable set of reference genes for gene expression analysis in C. elegans. Results Real-time quantitative PCR was used to evaluate the expression stability of 12 candidate reference genes (act-1, ama-1, cdc-42, csq-1, eif-3.C, mdh-1, gpd-2, pmp-3, tba-1, Y45F10D.4, rgs-6 and unc-16) in wild-type, three Ins/IGF-1 pathway mutants, dauers and L3 stage larvae. After geNorm analysis, cdc-42, pmp-3 and Y45F10D.4 showed the most stable expression pattern and were used to normalize 5 sod expression levels. Significant differences in mRNA levels were observed for sod-1 and sod-3 in daf-2 relative to wild-type animals, whereas in dauers sod-1, sod-3, sod-4 and sod-5 are differentially expressed relative to third stage larvae. Conclusion Our findings emphasize the importance of accurate normalization using stably expressed reference genes. The methodology used in this study is generally applicable to reliably quantify gene expression levels in the nematode C. elegans using quantitative PCR.
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Affiliation(s)
- David Hoogewijs
- Department of Biology and Center for Molecular Phylogeny and Evolution, Ghent University, B-9000 Ghent, Belgium.
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33
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Meyer JN, Boyd WA, Azzam GA, Haugen AC, Freedman JH, Van Houten B. Decline of nucleotide excision repair capacity in aging Caenorhabditis elegans. Genome Biol 2007; 8:R70. [PMID: 17472752 PMCID: PMC1929140 DOI: 10.1186/gb-2007-8-5-r70] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 11/03/2006] [Accepted: 05/01/2007] [Indexed: 11/29/2022] Open
Abstract
Repair of UVC-induced DNA damage in Caenorhabditis elegans is similar kinetically and genetically to repair in humans, and it slows significantly in aging C. elegans. Background Caenorhabditis elegans is an important model for the study of DNA damage and repair related processes such as aging, neurodegeneration, and carcinogenesis. However, DNA repair is poorly characterized in this organism. We adapted a quantitative polymerase chain reaction assay to characterize repair of DNA damage induced by ultraviolet type C (UVC) radiation in C. elegans, and then tested whether DNA repair rates were affected by age in adults. Results UVC radiation induced lesions in young adult C. elegans, with a slope of 0.4 to 0.5 lesions per 10 kilobases of DNA per 100 J/m2, in both nuclear and mitochondrial targets. L1 and dauer larvae were more than fivefold more sensitive to lesion formation than were young adults. Nuclear repair kinetics in a well expressed nuclear gene were biphasic in nongravid adult nematodes: a faster, first order (half-life about 16 hours) phase lasting approximately 24 hours and resulting in removal of about 60% of the photoproducts was followed by a much slower phase. Repair in ten nuclear DNA regions was 15% and 50% higher in more actively transcribed regions in young and aging adults, respectively. Finally, repair was reduced by 30% to 50% in each of the ten nuclear regions in aging adults. However, this decrease in repair could not be explained by a reduction in expression of nucleotide excision repair genes, and we present a plausible mechanism, based on gene expression data, to account for this decrease. Conclusion Repair of UVC-induced DNA damage in C. elegans is similar kinetically and genetically to repair in humans. Furthermore, this important repair process slows significantly in aging C. elegans, the first whole organism in which this question has been addressed.
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Affiliation(s)
- Joel N Meyer
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Windy A Boyd
- Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Gregory A Azzam
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Astrid C Haugen
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jonathan H Freedman
- Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Bennett Van Houten
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Alexander Drive, Research Triangle Park, NC 27709, USA
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34
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Ruzanov P, Riddle DL, Marra MA, McKay SJ, Jones SM. Genes that may modulate longevity in C. elegans in both dauer larvae and long-lived daf-2 adults. Exp Gerontol 2007; 42:825-39. [PMID: 17543485 PMCID: PMC2755518 DOI: 10.1016/j.exger.2007.04.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 03/29/2007] [Accepted: 04/03/2007] [Indexed: 10/23/2022]
Abstract
We used Serial Analysis of Gene Expression (SAGE) to compare the global transcription profiles of long-lived mutant daf-2 adults and dauer larvae, aiming to identify aging-related genes based on similarity of expression patterns. Genes that are expressed similarly in both long-lived types potentially define a common life-extending program. Comparison of eight SAGE libraries yielded a set of 120 genes, the expression of which was significantly different in long-lived worms vs. normal adults. The gene annotations indicate a strong link between oxidative stress and life span, further supporting the hypothesis that metabolic activity is a major determinant in longevity. The SAGE data show changes in mRNA levels for electron transport chain components, elevated expression of glyoxylate shunt enzymes and significantly reduced expression for components of the TCA cycle in longer-lived nematodes. We propose a model for enhanced longevity through a cytochrome c oxidase-mediated reduction in reactive oxygen species commonly held to be a major contributor to aging.
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Affiliation(s)
- Peter Ruzanov
- Genome Sciences Centre, BC Cancer Research Centre, Ste 100-570 West 7th Ave Vancouver, BC V5Z 4S6 Canada
| | - Donald L. Riddle
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4 Canada
| | - Marco A. Marra
- Genome Sciences Centre, BC Cancer Research Centre, Ste 100-570 West 7th Ave Vancouver, BC V5Z 4S6 Canada
| | - Sheldon J. McKay
- Genome Sciences Centre, BC Cancer Research Centre, Ste 100-570 West 7th Ave Vancouver, BC V5Z 4S6 Canada
| | - Steven M Jones
- Genome Sciences Centre, BC Cancer Research Centre, Ste 100-570 West 7th Ave Vancouver, BC V5Z 4S6 Canada
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35
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Houthoofd K, Vanfleteren JR. Public and private mechanisms of life extension in Caenorhabditis elegans. Mol Genet Genomics 2007; 277:601-17. [PMID: 17364197 DOI: 10.1007/s00438-007-0225-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Accepted: 02/20/2007] [Indexed: 12/18/2022]
Abstract
Model organisms have been widely used to study the ageing phenomenon in order to learn about human ageing. Although the phylogenetic diversity between vertebrates and some of the most commonly used model systems could hardly be greater, several mechanisms of life extension are public (common characteristic in divergent species) and likely share a common ancestry. Dietary restriction, reduced IGF-signaling and, seemingly, reduced ROS-induced damage are the best known mechanisms for extending longevity in a variety of organisms. In this review, we summarize the knowledge of ageing in the nematode Caenorhabditis elegans and compare the mechanisms of life extension with knowledge from other model organisms.
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Affiliation(s)
- Koen Houthoofd
- Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
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36
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McElwee JJ, Schuster E, Blanc E, Thornton J, Gems D. Erratum to "Diapause-associated metabolic traits reiterated in long-lived daf-2 mutants in the nematode Caenorhabditis elegans" [Mech. Ageing Dev. 127 (5) (2006) 458-472]. Mech Ageing Dev 2007; 127:922-36. [PMID: 17216712 DOI: 10.1016/j.mad.2006.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The longevity of the Caenorhabditis elegans diapausal dauer larva greatly exceeds that of the adult. Dauer formation and adult ageing are both regulated by insulin/IGF-1 signalling (IIS). Reduced IIS, e.g. by mutation of the daf-2 insulin/IGF-1 receptor gene, increases adult lifespan. This may reflect mis-expression in the adult of dauer longevity-assurance processes. Since IIS plays a central role in the regulation of metabolism, metabolic alterations shared by dauer larvae and daf-2 adults represent candidate mechanisms for lifespan determination. We have conducted a detailed comparison of transcript profile data from dauers and daf-2 mutant adults, focusing on expression of metabolic pathway genes. Our results imply up-regulation in both dauers and daf-2 mutant adults of gluconeogenesis, glyoxylate pathway activity, and trehalose biosynthesis. Down-regulation of the citric acid cycle and mitochondrial respiratory chain occurs in dauers, but not daf-2 adults. However, the F1 ATPase inhibitor was up-regulated in both, implying enhanced homeostasis in conditions where mitochondria are stressed. Overall, the data implies increased conversion of fat to carbohydrate, and conservation of ATP stocks in daf-2 mutant adults, suggesting a state of increased energy availability. We postulate that this fuels increased somatic maintenance activity, as suggested by the disposable soma theory.
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Affiliation(s)
- Joshua J McElwee
- Department of Biology, University College London, Gower Street, London WC1E 6BT, UK
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37
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Szewczyk NJ, Udranszky IA, Kozak E, Sunga J, Kim SK, Jacobson LA, Conley CA. Delayed development and lifespan extension as features of metabolic lifestyle alteration in C. elegans under dietary restriction. ACTA ACUST UNITED AC 2007; 209:4129-39. [PMID: 17023606 DOI: 10.1242/jeb.02492] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Studies of the model organism Caenorhabditis elegans have almost exclusively utilized growth on a bacterial diet. Such culturing presents a challenge to automation of experimentation and introduces bacterial metabolism as a secondary concern in drug and environmental toxicology studies. Axenic cultivation of C. elegans can avoid these problems, yet past work suggests that axenic growth is unhealthy for C. elegans. Here we employ a chemically defined liquid medium to culture C. elegans and find development slows, fecundity declines, lifespan increases, lipid and protein stores decrease, and gene expression changes relative to that on a bacterial diet. These changes do not appear to be random pathologies associated with malnutrition, as there are no developmental delays associated with starvation, such as L1 or dauer diapause. Additionally, development and reproductive period are fixed percentages of lifespan regardless of diet, suggesting that these alterations are adaptive. We propose that C. elegans can exist as a healthy animal with at least two distinct adult life histories. One life history maximizes the intrinsic rate of population increase, the other maximizes the efficiency of exploitation of the carrying capacity of the environment. Microarray analysis reveals increased transcript levels of daf-16 and downstream targets and past experiments demonstrate that DAF-16 (FOXO) acting on downstream targets can influence all of the phenotypes we see altered in maintenance medium. Thus, life history alteration in response to diet may be modulated by DAF-16. Our observations introduce a powerful system for automation of experimentation on healthy C. elegans and for systematic analysis of the profound impact of diet on animal physiology.
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38
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Braeckman BP, Vanfleteren JR. Genetic control of longevity in C. elegans. Exp Gerontol 2007; 42:90-8. [PMID: 16829009 DOI: 10.1016/j.exger.2006.04.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 04/28/2006] [Indexed: 11/22/2022]
Abstract
The nematode Caenorhabditis elegans has proven to be a very useful tool for studying the genetics of longevity. Over 70 genes have been found to influence lifespan in this worm. Those related to the Ins/IGF signaling pathway are among the best studied and will be focused on in this review. The master regulator of this pathway, the forkhead transcription factor DAF-16, can activate an enhanced life maintenance program in response to environmental and gonadal inputs. DAF-16 up- and downregulates expression of many genes leading to metabolic alterations and increased stress and microbial resistance. This is generally confirmed by biochemical and physiological data. Longevity mutants are not hypometabolic and probably produce more reactive oxygen species than wild type. However, their high antioxidant capacity may result in lower oxidative damage. Enhanced molecular turnover rates may also play a role in their longevity phenotype.
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Affiliation(s)
- Bart P Braeckman
- Biology Department, Ghent University, K.L.Ledeganckstraat 35, B-9000 Ghent, Belgium.
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39
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Wolff S, Dillin A. The trifecta of aging in Caenorhabditis elegans. Exp Gerontol 2006; 41:894-903. [PMID: 16919905 DOI: 10.1016/j.exger.2006.06.054] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 06/06/2006] [Accepted: 06/12/2006] [Indexed: 11/28/2022]
Abstract
Insulin signaling, mitochondrial respiration, and dietary restriction share conserved roles not only in the regulation of lifespan, but also in the timing and control of diverse functions such as reproduction, stress resistance and metabolism. These autonomous pathways differ in their dependence on known transcription factors and in their temporal requirements, but converge to manipulate the core set of physiological systems necessary for extended lifespan in worms. Recent work suggests that components of these pleiotrophic pathways might be manipulated specifically for their effects on aging without affecting additional downstream functions. Examination of these findings will help us to understand how the molecular mechanisms of distinct pathways can unite in the regulation of longevity.
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Affiliation(s)
- Suzanne Wolff
- The Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
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40
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McElwee JJ, Schuster E, Blanc E, Thornton J, Gems D. Diapause-associated metabolic traits reiterated in long-lived daf-2 mutants in the nematode Caenorhabditis elegans. Mech Ageing Dev 2006; 127:458-72. [PMID: 16522328 DOI: 10.1016/j.mad.2006.01.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 12/15/2005] [Accepted: 01/19/2006] [Indexed: 11/16/2022]
Abstract
The longevity of the Caenorhabditis elegans diapausal dauer larva greatly exceeds that of the adult. Dauer formation and adult ageing are both regulated by insulin/IGF-1 signaling (IIS). Reduced IIS, e.g. by mutation of the daf-2 insulin/IGF-1 receptor gene, increases adult lifespan. This may reflect mis-expression in the adult of dauer longevity-assurance processes. Since IIS plays a central role in the regulation of metabolism, metabolic alterations shared by dauer larvae and daf-2 adults represent candidate mechanisms for lifespan determination. We have conducted a detailed comparison of transcript profile data from dauers and daf-2 mutant adults, focusing on expression of metabolic pathway genes. Our results imply up-regulation in both dauers and daf-2 mutant adults of gluconeogenesis, glyoxylate pathway activity, and trehalose biosynthesis. Down-regulation of the citric acid cycle and mitochondrial respiratory chain occurs in dauers, but not daf-2 adults. However, the F(1) ATPase inhibitor was up-regulated in both, implying enhanced homeostasis in conditions where mitochondria are stressed. Overall, the data implies increased conversion of fat to carbohydrate, and conservation of ATP stocks in daf-2 mutant adults, suggesting a state of increased energy availability. We postulate that this fuels increased somatic maintenance activity, as suggested by the disposable soma theory.
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41
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Piper MD, Selman C, McElwee JJ, Partridge L. Models of insulin signalling and longevity. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.ddmod.2005.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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42
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Burnell AM, Houthoofd K, O'Hanlon K, Vanfleteren JR. Alternate metabolism during the dauer stage of the nematode Caenorhabditis elegans. Exp Gerontol 2005; 40:850-6. [PMID: 16221538 DOI: 10.1016/j.exger.2005.09.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Revised: 09/19/2005] [Accepted: 09/19/2005] [Indexed: 11/16/2022]
Abstract
When environmental conditions are unsuitable to support nematode reproduction, Caenorhabditis elegans arrests development before the onset of sexual maturity and specialised 'dauer' larvae, adapted for dispersal, and extended diapause are formed. Dauer larvae do not feed and their metabolism is dependent on internal food reserves. Adult worms which express defects in the insulin/insulin-like growth factor receptor DAF-2 also display enhanced longevity. Whole genome mRNA expression profiling has demonstrated that C. elegans dauer larvae and daf-2 adults have similar transcription profiles for a cohort of longevity genes. Important components of this enhanced longevity system are the alpha-crystallin family of small heat shock proteins, anti-ROS defence systems, increased activity of cellular detoxification processes and possibly also increased chromatin stability and decreased protein turnover. Anaerobic fermentation pathways are upregulated in dauer larvae, while long-lived daf-2 adults appear to have normal oxidative metabolism. Anabolic pathways are down regulated in dauer larvae (and possibly in daf-2 adults as well), and energy consumption appears to be diverted to enhanced cellular maintenance and detoxification processes in both systems.
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Affiliation(s)
- Ann M Burnell
- Department of Biology, Institute of Bioengineering and Agroecology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland.
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