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D'Alfonso A, Micheli G, Camilloni G. rDNA transcription, replication and stability in Saccharomyces cerevisiae. Semin Cell Dev Biol 2024; 159-160:1-9. [PMID: 38244478 DOI: 10.1016/j.semcdb.2024.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 12/20/2023] [Accepted: 01/10/2024] [Indexed: 01/22/2024]
Abstract
The ribosomal DNA locus (rDNA) is central for the functioning of cells because it encodes ribosomal RNAs, key components of ribosomes, and also because of its links to fundamental metabolic processes, with significant impact on genome integrity and aging. The repetitive nature of the rDNA gene units forces the locus to maintain sequence homogeneity through recombination processes that are closely related to genomic stability. The co-presence of basic DNA transactions, such as replication, transcription by major RNA polymerases, and recombination, in a defined and restricted area of the genome is of particular relevance as it affects the stability of the rDNA locus by both direct and indirect mechanisms. This condition is well exemplified by the rDNA of Saccharomyces cerevisiae. In this review we summarize essential knowledge on how the complexity and overlap of different processes contribute to the control of rDNA and genomic stability in this model organism.
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Affiliation(s)
- Anna D'Alfonso
- Dipartimento di Biologia e Biotecnologie C. Darwin, Università degli studi di Roma, Sapienza, Rome, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Giorgio Camilloni
- Dipartimento di Biologia e Biotecnologie C. Darwin, Università degli studi di Roma, Sapienza, Rome, Italy.
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2
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Zsichla L, Müller V. Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors. Viruses 2023; 15:175. [PMID: 36680215 PMCID: PMC9863423 DOI: 10.3390/v15010175] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
The clinical course and outcome of COVID-19 are highly variable, ranging from asymptomatic infections to severe disease and death. Understanding the risk factors of severe COVID-19 is relevant both in the clinical setting and at the epidemiological level. Here, we provide an overview of host, viral and environmental factors that have been shown or (in some cases) hypothesized to be associated with severe clinical outcomes. The factors considered in detail include the age and frailty, genetic polymorphisms, biological sex (and pregnancy), co- and superinfections, non-communicable comorbidities, immunological history, microbiota, and lifestyle of the patient; viral genetic variation and infecting dose; socioeconomic factors; and air pollution. For each category, we compile (sometimes conflicting) evidence for the association of the factor with COVID-19 outcomes (including the strength of the effect) and outline possible action mechanisms. We also discuss the complex interactions between the various risk factors.
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Affiliation(s)
- Levente Zsichla
- Institute of Biology, Eötvös Loránd University, 1117 Budapest, Hungary
- National Laboratory for Health Security, Eötvös Loránd University, 1117 Budapest, Hungary
| | - Viktor Müller
- Institute of Biology, Eötvös Loránd University, 1117 Budapest, Hungary
- National Laboratory for Health Security, Eötvös Loránd University, 1117 Budapest, Hungary
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3
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Shah AA, Liu B, Tang Z, Wang W, Yang W, Hu Q, Liu Y, Zhang N, Liu K. Hydrogen sulfide treatment at the late growth stage of Saccharomyces cerevisiae extends chronological lifespan. Aging (Albany NY) 2021; 13:9859-9873. [PMID: 33744847 PMCID: PMC8064171 DOI: 10.18632/aging.202738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 02/16/2021] [Indexed: 11/25/2022]
Abstract
Previous studies demonstrated that lifelong treatment with a slow H2S releasing donor extends yeast chronological lifespan (CLS), but it is not clear when the action of H2S benefits to CLS during yeast growth. Here, we show that short H2S treatments by using NaHS as a fast H2S releasing donor at 96 hours after inoculation extended yeast CLS while NaHS treatments earlier than 72 hours after inoculation failed to do so. To reveal the mechanism, we analyzed the transcriptome of yeast cells with or without the early and late NaHS treatments. We found that both treatments had similar effects on pathways related to CLS regulation. Follow-up qPCR and ROS analyses suggest that altered expression of some antioxidant genes by the early NaHS treatments were not stable enough to benefit CLS. Moreover, transcriptome data also indicated that some genes were regulated differently by the early and late H2S treatment. Specifically, we found that the expression of YPK2, a human SGK2 homolog and also a key regulator of the yeast cell wall synthesis, was significantly altered by the late NaHS treatment but not altered by the early NaHS treatment. Finally, the key role of YPK2 in CLS regulation by H2S is revealed by CLS data showing that the late NaHS treatment did not enhance the CLS of a ypk2 knockout mutant. This study sheds light on the molecular mechanism of CLS extension induced by H2S, and for the first time addresses the importance of H2S treatment timing for lifespan extension.
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Affiliation(s)
- Arman Ali Shah
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Binghua Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Zhihuai Tang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Wang Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Wenjie Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Quanjun Hu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Yan Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Nianhui Zhang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
| | - Ke Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China
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Zhu A, Ji Z, Zhao J, Zhang W, Sun Y, Zhang T, Gao S, Li G, Wang Q. Effect of Euphorbia factor L1 on intestinal barrier impairment and defecation dysfunction in Caenorhabditis elegans. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 65:153102. [PMID: 31654989 DOI: 10.1016/j.phymed.2019.153102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/22/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Euphorbia factor L1 (EFL1) is a lathyrane-type diterpenoid from the medicinal herb Euphorbia lathyris L., and has been reported with intestinal toxicity, but the potential mechanisms remain unknown. PURPOSE The objective of this study was to investigate the intestinal toxicity of EFL1 and the underlying mechanisms using nematode Caenorhabditis elegans. METHODS C. elegans were exposed to 0-200 μM EFL1 for 72 h, then the survival rate, body length and body width, locomotion and chemoreception behavior, intestinal ROS and lipofuscin accumulation, intestinal permeability, and defecation rhythm were detected. The γ-aminobutyric acid(GABA) energic neurons AVL and DVB were shown via green fluorescent protein under a laser scanning confocal microscope. The structure of GABA transporter UNC-47 were predicted by homology modeling, and the interaction between EFL1 and UNC-47 was simulated by molecular docking. The mRNA expression of genes related to oxidative stress, intestinal permeability and defecation after EFL1 exposure were detected by RT-qPCR. RESULTS EFL1 did not induce lethality of nematodes. The general toxicity was characterized by abnormal growth, locomotion and chemoreception. The intestinal barrier was leaky, due to down-regulated cell junction and active cation transport. The mean defecation cycle length in nematodes was decreased, relating to disorder vesicular and ion transport, enhanced rhythm behavior and muscle contraction. The dysfunctional defecation also attributed to injured UNC-47 protein, as well as GABAergic neurons AVL and DVB. Excessive ROS and lipofuscin accumulation were observed in intestine, along with activation of antioxidant enzymes of SOD, COQ7 and CAT. CONCLUSION This study elucidated the EFL1-induced intestinal toxicity in nematodes, characterized as leaky intestinal barrier and accelerated defecation behavior. The underlying mechanisms were involved in oxidative stress, cell junctions, transportation, rhythm behavior, muscle contraction, and GABAergic neurons.
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Affiliation(s)
- An Zhu
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Zonghui Ji
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Jingwei Zhao
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Wenjing Zhang
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing Center of Preventive Medicine Research, Beijing 100013, China; School of Public Health, Capital Medical University, Beijing 100069, China
| | - Yuqing Sun
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Tao Zhang
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China
| | - Shan Gao
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing Center of Preventive Medicine Research, Beijing 100013, China
| | - Guojun Li
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing Center of Preventive Medicine Research, Beijing 100013, China; School of Public Health, Capital Medical University, Beijing 100069, China.
| | - Qi Wang
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Key Laboratory of State Administration of Traditional Chinese Medicine for Compatibility Toxicology, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China.
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5
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Jazwinski SM, Kim S. Examination of the Dimensions of Biological Age. Front Genet 2019; 10:263. [PMID: 30972107 PMCID: PMC6445152 DOI: 10.3389/fgene.2019.00263] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 03/08/2019] [Indexed: 12/22/2022] Open
Abstract
The concept of biological age has been used more and more frequently in aging research in attempts to measure the progress of the biological aging process as opposed to the simple passage of time. Several approaches to quantify biological age have been utilized, including the use of biomarkers in the form of serum analytes, epigenetic markers, and deficit or frailty indices. Among these methods, the deficit index possesses a theoretical basis grounded in systems biology by incorporating networks, with their emergent properties, to describe the complex aging system. Application of the deficit index in human aging studies points to the increased energetic demands posed by an aging system that is losing integration. Different aspects of mitochondrial function appear to be responsible in males and females. The gut microbiome loses complexity in tandem with the host, as biological age increases, with likely impact on host metabolism and immunity. Specific DNA methylation changes are associated with biological age. They suggest declining connectivity within the aging network, at the cellular level. The deficit/frailty index may account for at least part of the departure at older ages of the observed mortality in the population from the exponential increase modeled by the Gompertz equation.
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Affiliation(s)
- S Michal Jazwinski
- Tulane Center for Aging, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, United States
| | - Sangkyu Kim
- Tulane Center for Aging, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, United States
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6
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Maskell DL, Kennedy AI, Hodgson JA, Smart KA. Impact of Carbohydrate Composition of Media on Lager Yeast Replicative Lifespan. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-59-0111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Dawn L. Maskell
- School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP, UK
| | - Alan I. Kennedy
- Scottish Courage Brewing Limited, Technical Centre, Edinburgh, EH8 8DD, UK
| | - Jeff A. Hodgson
- Scottish Courage Brewing Limited, Technical Centre, Edinburgh, EH8 8DD, UK
| | - Katherine A. Smart
- School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP, UK
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Mena A, Medina DA, García-Martínez J, Begley V, Singh A, Chávez S, Muñoz-Centeno MC, Pérez-Ortín JE. Asymmetric cell division requires specific mechanisms for adjusting global transcription. Nucleic Acids Res 2017; 45:12401-12412. [PMID: 29069448 PMCID: PMC5716168 DOI: 10.1093/nar/gkx974] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/10/2017] [Indexed: 12/19/2022] Open
Abstract
Most cells divide symmetrically into two approximately identical cells. There are many examples, however, of asymmetric cell division that can generate sibling cell size differences. Whereas physical asymmetric division mechanisms and cell fate consequences have been investigated, the specific problem caused by asymmetric division at the transcription level has not yet been addressed. In symmetrically dividing cells the nascent transcription rate increases in parallel to cell volume to compensate it by keeping the actual mRNA synthesis rate constant. This cannot apply to the yeast Saccharomyces cerevisiae, where this mechanism would provoke a never-ending increasing mRNA synthesis rate in smaller daughter cells. We show here that, contrarily to other eukaryotes with symmetric division, budding yeast keeps the nascent transcription rates of its RNA polymerases constant and increases mRNA stability. This control on RNA pol II-dependent transcription rate is obtained by controlling the cellular concentration of this enzyme.
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Affiliation(s)
- Adriana Mena
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
| | - Daniel A Medina
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
| | - José García-Martínez
- Departamento de Genética and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
| | - Victoria Begley
- Departamento de Genética, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, 41013 Sevilla, Spain
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716, USA
| | - Sebastián Chávez
- Departamento de Genética, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, 41013 Sevilla, Spain
| | - Mari C Muñoz-Centeno
- Departamento de Genética, Universidad de Sevilla and Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, 41013 Sevilla, Spain
| | - José E Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular and E.R.I. Biotecmed, Universitat de València, Dr. Moliner, 50, Burjassot 46100, Valencia, Spain
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8
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The Gcn4 transcription factor reduces protein synthesis capacity and extends yeast lifespan. Nat Commun 2017; 8:457. [PMID: 28878244 PMCID: PMC5587724 DOI: 10.1038/s41467-017-00539-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 07/07/2017] [Indexed: 01/21/2023] Open
Abstract
In Saccharomyces cerevisiae, deletion of large ribosomal subunit protein-encoding genes increases the replicative lifespan in a Gcn4-dependent manner. However, how Gcn4, a key transcriptional activator of amino acid biosynthesis genes, increases lifespan, is unknown. Here we show that Gcn4 acts as a repressor of protein synthesis. By analyzing the messenger RNA and protein abundance, ribosome occupancy and protein synthesis rate in various yeast strains, we demonstrate that Gcn4 is sufficient to reduce protein synthesis and increase yeast lifespan. Chromatin immunoprecipitation reveals Gcn4 binding not only at genes that are activated, but also at genes, some encoding ribosomal proteins, that are repressed upon Gcn4 overexpression. The promoters of repressed genes contain Rap1 binding motifs. Our data suggest that Gcn4 is a central regulator of protein synthesis under multiple perturbations, including ribosomal protein gene deletions, calorie restriction, and rapamycin treatment, and provide an explanation for its role in longevity and stress response. The transcription factor Gcn4 is known to regulate yeast amino acid synthesis. Here, the authors show that Gcn4 also acts as a repressor of protein biosynthesis in a range of conditions that enhance yeast lifespan, such as ribosomal protein knockout, calorie restriction or mTOR inhibition.
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9
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Saghiv MS, Sira DB, Goldhammer E, Sagiv M. The effects of aerobic and anaerobic exercises on circulating soluble-Klotho and IGF-I in young and elderly adults and in CAD patients. J Circ Biomark 2017; 6:1849454417733388. [PMID: 29081845 PMCID: PMC5644364 DOI: 10.1177/1849454417733388] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 08/09/2017] [Indexed: 12/15/2022] Open
Abstract
Different studies support the notion that chronic aerobic exercises training can influence the circulating levels of soluble-Klotho (s-Klotho) and insulin-like growth factor 1 (IGF-I). The effects of s-Klotho include improving the quality of life, alleviating the negative impact of age on the body's work capacity, and possibly increasing longevity. This review provides an overview of the latest findings in this field of research in humans. The different modes of dynamic exercise and their impact on circulating levels of s-Klotho and IGF-I in young adult athletes, untrained young adults, trained healthy older adults, untrained healthy older adults, and coronary artery disease (CAD) patients are reviewed and discussed. Together these findings suggest that long-lasting (chronic) aerobic exercise training is probably one of the antiaging factors that counteract the aging and CAD process by increasing the circulating s-Klotho and lowering the IGF-I levels. However, following anaerobic exercise training the opposite occurs. The exact metabolic and physiological pathways involved in the activity of these well-trained young and master sportsmen should be further studied and elucidated. The purpose of this review was to provide a clarification regarding the roles of s-Klotho and intensities and durations of different exercise on human health.
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Affiliation(s)
- Moran S Saghiv
- Exercise Physiology Department, University of Mary, Bismarck, ND, USA
| | - D Ben Sira
- Life Sciences Department, Wingate College, Wingate, Israel
| | - E Goldhammer
- Heart Institute Bnai-Zion Haifa Medical Center, Technion Institute, Haifa, Israel
| | - M Sagiv
- Life Sciences Department, Wingate College, Wingate, Israel
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10
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Lee JY, Shin C, Baik I. Longitudinal associations between micronutrient consumption and leukocyte telomere length. J Hum Nutr Diet 2016; 30:236-243. [DOI: 10.1111/jhn.12403] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- J.-Y. Lee
- Department of Foods and Nutrition; College of Natural Sciences; Kookmin University; Seoul Korea
| | - C. Shin
- Department of Internal Medicine; Korea University Ansan Hospital; Ansan-si Korea
| | - I. Baik
- Department of Foods and Nutrition; College of Natural Sciences; Kookmin University; Seoul Korea
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11
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Affiliation(s)
- S Michal Jazwinski
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1901 Perdido Street, Box P7-2, New Orleans, Louisiana 70112 USA
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12
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Shin C, Yun CH, Yoon DW, Baik I. Association between Snoring and Leukocyte Telomere Length. Sleep 2016; 39:767-72. [PMID: 26715224 DOI: 10.5665/sleep.5624] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 11/21/2015] [Indexed: 12/17/2022] Open
Abstract
STUDY OBJECTIVES Data on the association between snoring and telomere length, an indicator of biological aging, are very limited. Moreover, no polysomnography (PSG) studies on this association in a general population have been conducted. Our study aimed to evaluate the association between snoring and leukocyte telomere length (LTL) using PSG and a questionnaire. METHODS A cross-sectional PSG study embedded in a population-based cohort from the Korean Genome Epidemiology Study was conducted in 2010-2013. During the same period, questionnaire-based interviews, blood collection, and relative LTL assays were conducted. A total of 887 Korean men and women aged 50-79 y with an apnea-hypopnea index (AHI) < 15 determined in the PSG study were included in the study. RESULTS We observed that the percentage of time spent snoring during sleep (% time spent snoring) assessed by PSG was inversely associated with LTL even after adjusting for potential risk factors and AHI. In the linear regression association between tertiles of percentage of time spent snoring and log-transformed LTL, coefficient estimates (P value) were -0.076 (< 0.05) for the second tertile and -0.084 (< 0.01) for the third tertile compared with the bottom tertile. When LTL was compared according to snoring status determined using PSG and questionnaire information, both primary snorers and those with mild sleep apnea (5 ≤ AHI < 15) had shorter LTL than nonsnorers. CONCLUSIONS Our findings suggest that snoring may influence telomere attrition independent of sleep apnea.
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Affiliation(s)
- Chol Shin
- Department of Internal Medicine, Korea University Ansan Hospital, Ansan.,Institute of Human Genomic Study, Korea University Ansan Hospital, Ansan
| | - Chang-Ho Yun
- Department of Neurology and Bundang Clinical Neuroscience Institute, Seoul National University Bundang Hospital, Seongnam
| | - Dae Wui Yoon
- Department of Pharmacology, Seoul National University College of Medicine, Seoul
| | - Inkyung Baik
- Department of Foods and Nutrition, College of Natural Sciences, Kookmin University, Seoul, Republic of Korea
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13
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Kim S, Welsh DA, Myers L, Cherry KE, Wyckoff J, Jazwinski SM. Non-coding genomic regions possessing enhancer and silencer potential are associated with healthy aging and exceptional survival. Oncotarget 2016; 6:3600-12. [PMID: 25682868 PMCID: PMC4414140 DOI: 10.18632/oncotarget.2877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/08/2014] [Indexed: 01/04/2023] Open
Abstract
We have completed a genome-wide linkage scan for healthy aging using data collected from a family study, followed by fine-mapping by association in a separate population, the first such attempt reported. The family cohort consisted of parents of age 90 or above and their children ranging in age from 50 to 80. As a quantitative measure of healthy aging, we used a frailty index, called FI34, based on 34 health and function variables. The linkage scan found a single significant linkage peak on chromosome 12. Using an independent cohort of unrelated nonagenarians, we carried out a fine-scale association mapping of the region suggestive of linkage and identified three sites associated with healthy aging. These healthy-aging sites (HASs) are located in intergenic regions at 12q13-14. HAS-1 has been previously associated with multiple diseases, and an enhancer was recently mapped and experimentally validated within the site. HAS-2 is a previously uncharacterized site possessing genomic features suggestive of enhancer activity. HAS-3 contains features associated with Polycomb repression. The HASs also contain variants associated with exceptional longevity, based on a separate analysis. Our results provide insight into functional genomic networks involving non-coding regulatory elements that are involved in healthy aging and longevity.
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Affiliation(s)
- Sangkyu Kim
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - David A Welsh
- Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Leann Myers
- Department of Biostatistics and Bioinformatics, School of Public Health and Tropical Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - Katie E Cherry
- Department of Psychology, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Jennifer Wyckoff
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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14
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Lee JY, Jun NR, Yoon D, Shin C, Baik I. Association between dietary patterns in the remote past and telomere length. Eur J Clin Nutr 2015; 69:1048-52. [DOI: 10.1038/ejcn.2015.58] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 02/23/2015] [Accepted: 03/10/2015] [Indexed: 01/21/2023]
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15
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Jazwinski SM. The retrograde response: a conserved compensatory reaction to damage from within and from without. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 127:133-54. [PMID: 25149216 DOI: 10.1016/b978-0-12-394625-6.00005-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The retrograde response was discovered in Saccharomyces cerevisiae as a signaling pathway from the mitochondrion to the nucleus that triggers an array of gene regulatory changes in the latter. The activation of the retrograde response compensates for the deficits associated with aging, and thus it extends yeast replicative life span. The retrograde response is activated by the progressive decline in mitochondrial membrane potential during aging that is the result of increasing mitochondrial dysfunction. The ensuing metabolic adaptations and stress resistance can only delay the inevitable demise of the yeast cell. The retrograde response is embedded in a network of signal transduction pathways that impinge upon virtually every aspect of cell physiology. Thus, its manifestations are complicated. Many of these pathways have been implicated in life span regulation quite independently of the retrograde response. Together, they operate in a delicate balance in promoting longevity. The retrograde response is closely aligned with cell quality control, often performing when quality control is not sufficient to assure longevity. Among the key pathways related to this aspect of retrograde signaling are target of rapamycin and ceramide signaling. The retrograde response can also be found in other organisms, including Caenorhabditis elegans, Drosophila melanogaster, mouse, and human, where it exhibits an ever-increasing complexity that may be corralled by the transcription factor NFκB. The retrograde response may have evolved as a cytoprotective mechanism that senses and defends the organism from pathogens and environmental toxins.
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Affiliation(s)
- S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
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SIRT6: a promising target for cancer prevention and therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 818:181-96. [PMID: 25001537 DOI: 10.1007/978-1-4471-6458-6_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many of the pathologies associated with the aging process also contribute to tumor initiation, growth or metastasis. Insights from biogerontology may be instrumental for developing new therapies for cancer. This chapter highlights the rationale for combining biogerontology and cancer research to generate new strategies for cancer treatment. In particular, this chapter focuses on one gene, SIRT6, which has emerged as an important regulator of longevity in mammals and appears to have multiple biochemical functions, which antagonize tumor development and may be useful in cancer prevention and treatment.
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Nyström T, Liu B. Protein quality control in time and space - links to cellular aging. FEMS Yeast Res 2013; 14:40-8. [PMID: 24103195 DOI: 10.1111/1567-1364.12095] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 07/15/2013] [Accepted: 09/06/2013] [Indexed: 01/08/2023] Open
Abstract
The evolutionary theory of aging regards aging as an evolved characteristic of the soma, and proponents of the theory state that selection does not allow the evolution of aging in unicellular species lacking a soma-germ demarcation. However, the life history of some microorganisms, reproducing vegetatively by either budding or binary fission, has been demonstrated to encompass an ordered, polar-dependent, segregation of damage leading to an aging cell lineage within the clonal population. In the yeast Saccharomyces cerevisiae and the bacterium Escherichia coli, such segregation is under genetic control and includes an asymmetrical inheritance of protein aggregates and inclusions. Herein, the ultimate and proximate causation for such an asymmetrical inheritance, with special emphasis on damaged/aggregated proteins in budding yeast, is reviewed.
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Affiliation(s)
- Thomas Nyström
- Department of Chemistry and Molecular Biology, Göteborg University, Göteborg, Sweden
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18
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Martien S, Pluquet O, Vercamer C, Malaquin N, Martin N, Gosselin K, Pourtier A, Abbadie C. Cellular senescence involves an intracrine prostaglandin E2 pathway in human fibroblasts. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1217-27. [DOI: 10.1016/j.bbalip.2013.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Braeckman BP, Houthoofd K, Vanfleteren JR. Patterns of metabolic activity during aging of the wild type and longevity mutants of Caenorhabditis elegans. J Am Aging Assoc 2013; 23:55-73. [PMID: 23604840 DOI: 10.1007/s11357-000-0007-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
At least three mechanisms determine life span in Caenorhabditis elegans. An insulin-like signaling pathway regulates dauer diapause, reproduction and longevity. Reduction-or loss-of-function mutations in this pathway can extend longevity substantially, suggesting that the wild-type alleles shorten life span. The mutations extend life span by activating components of a dauer longevity assurance program in adult life, resulting in altered metabolism and enhanced stress resistance. The Clock (Clk) genes regulate many temporal processes, including life span. Mutation in the Clk genes clk-1 and gro-1 mildly affect energy production, but repress energy consumption dramatically, thereby reducing the rate of anabolic metabolism and lengthening life span. Dietary restriction, either imposed by mutation or by the culture medium increases longevity and uncovers a third mechanism of life span determination. Dietary restriction likely elicits the longevity assurance program. There is still uncertainty as to whether these pathways converge on daf-16 to activate downstream longevity effector genes such as ctl-1 and sod-3. There is overwhelming evidence that the interplay between reactive oxygen species (ROS) and the capacity to resist oxidative stress controls the aging process and longevity. It is as yet not clear whether metabolic homeostasis collapses with age as a direct result of ROS-derived damage or is selectively repressed by longevity-determining genes. The dramatic decline of protein turnover during senescence results in the accumulation of altered enzymes and in a gradual decline of metabolic performance eventually followed by fatal failure of the system.
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Affiliation(s)
- B P Braeckman
- Department of Biology, University of Gent, Ledeganckstraat 35, B-9000 Gent, Belgium
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20
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Jazwinski SM. The retrograde response: when mitochondrial quality control is not enough. BIOCHIMICA ET BIOPHYSICA ACTA 2013. [PMID: 22374136 DOI: 10.1016/j.bbamcr.2012.02.010 [epub ahead of print]] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Mitochondria are responsible for generating adenosine triphosphate (ATP) and metabolic intermediates for biosynthesis. These dual functions require the activity of the electron transport chain in the mitochondrial inner membrane. The performance of these electron carriers is imperfect, resulting in release of damaging reactive oxygen species. Thus, continued mitochondrial activity requires maintenance. There are numerous means by which this quality control is ensured. Autophagy and selective mitophagy are among them. However, the cell inevitably must compensate for declining quality control by activating a variety of adaptations that entail the signaling of the presence of mitochondrial dysfunction to the nucleus. The best known of these is the retrograde response. This signaling pathway is triggered by the loss of mitochondrial membrane potential, which engages a series of signal transduction proteins, and it culminates in the induction of a broad array of nuclear target genes. One of the hallmarks of the retrograde response is its capacity to extend the replicative life span of the cell. The retrograde signaling pathway interacts with several other signaling pathways, such as target of rapamycin (TOR) and ceramide signaling. All of these pathways respond to stress, including metabolic stress. The retrograde response is also linked to both autophagy and mitophagy at the gene and protein activation levels. Another quality control mechanism involves age-asymmetry in the segregation of dysfunctional mitochondria. One of the processes that impinge on this age-asymmetry is related to biogenesis of the organelle. Altogether, it is apparent that mitochondrial quality control constitutes a complex network of processes, whose full understanding will require a systems approach. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids.
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Affiliation(s)
- S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
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21
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Jazwinski SM. The retrograde response: when mitochondrial quality control is not enough. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:400-9. [PMID: 22374136 DOI: 10.1016/j.bbamcr.2012.02.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/10/2012] [Accepted: 02/12/2012] [Indexed: 12/28/2022]
Abstract
Mitochondria are responsible for generating adenosine triphosphate (ATP) and metabolic intermediates for biosynthesis. These dual functions require the activity of the electron transport chain in the mitochondrial inner membrane. The performance of these electron carriers is imperfect, resulting in release of damaging reactive oxygen species. Thus, continued mitochondrial activity requires maintenance. There are numerous means by which this quality control is ensured. Autophagy and selective mitophagy are among them. However, the cell inevitably must compensate for declining quality control by activating a variety of adaptations that entail the signaling of the presence of mitochondrial dysfunction to the nucleus. The best known of these is the retrograde response. This signaling pathway is triggered by the loss of mitochondrial membrane potential, which engages a series of signal transduction proteins, and it culminates in the induction of a broad array of nuclear target genes. One of the hallmarks of the retrograde response is its capacity to extend the replicative life span of the cell. The retrograde signaling pathway interacts with several other signaling pathways, such as target of rapamycin (TOR) and ceramide signaling. All of these pathways respond to stress, including metabolic stress. The retrograde response is also linked to both autophagy and mitophagy at the gene and protein activation levels. Another quality control mechanism involves age-asymmetry in the segregation of dysfunctional mitochondria. One of the processes that impinge on this age-asymmetry is related to biogenesis of the organelle. Altogether, it is apparent that mitochondrial quality control constitutes a complex network of processes, whose full understanding will require a systems approach. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids.
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Affiliation(s)
- S Michal Jazwinski
- Tulane Center for Aging and Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
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22
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Pence BD, Martin SA, Woods JA. Exercise Training and Immunosenescence. Am J Lifestyle Med 2011. [DOI: 10.1177/1559827610392317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
During the aging process, a decrease in the ability of the immune system to control infection, known as immunosenescence, takes place. Paradoxically, aging also results in chronic low-level inflammation and exaggerated inflammatory responses. A number of studies have investigated the effects of a variety of exercise training interventions on the immune system both in humans and using animal models of aging. Cross-sectional studies that compared masters athletes to untrained, age-matched controls found that the athletes had significantly better immune function, but these studies suffered because of the difficulty in generalizing results from highly trained athletes to a general population of physically active older adults. Prospective studies in humans have attempted to address this, but these studies have resulted in sometimes equivocal findings, possibly as a result of the differences in exercise training programs used. Finally, animal studies, both observational and mechanistic, have almost universally supported the exercise effect on enhancing immune status in the aged. More research is needed to determine the mechanism by which exercise influences immunity in the aged and to identify exercise training programs for use in this population. It is clear, however, that exercise is likely to be effective at boosting immunity in the older people when undertaken regularly.
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Affiliation(s)
- Brandt D. Pence
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Stephen A. Martin
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Jeffrey A. Woods
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, Department of Pathology, University of Illinois at Urbana-Champaign, Urbana, Illinois, Integrative Immunology and Behavior Program, University of Illinois at Urbana-Champaign, Urbana, Illinois,
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Lam YT, Aung-Htut MT, Lim YL, Yang H, Dawes IW. Changes in reactive oxygen species begin early during replicative aging of Saccharomyces cerevisiae cells. Free Radic Biol Med 2011; 50:963-70. [PMID: 21255640 DOI: 10.1016/j.freeradbiomed.2011.01.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 12/22/2010] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
Increased reactive oxygen species (ROS) are a feature of aging cells, but little is known about when ROS generation begins as cells age. Here we show how ROS change in Saccharomyces cerevisiae cells throughout their early replicative life span using the fluorescent ROS indicator dihydroethidium (DHE), which has some specificity for the superoxide anion. Cells in a particular age range were heterogeneous with respect to their ROS burden. Surprisingly, some cells as young as 5-7 generations acquired a greatly increased level of ROS detected by DHE relative to virgin cells. By 12 generations 50% of cells had a substantial ROS burden despite being only halfway through their life span. In contrast to the wild type, cells of a sir2 mutant had lower levels of ROS reacting with DHE. Daughters from older mothers had low ROS levels, and this asymmetric distribution of ROS was SIR2-independent. Mitochondrial fragmentation also began to occur in cells after 4 generations and increased markedly as cells aged. Daughter cells regenerated normal tubular mitochondria despite the fragmentation of mitochondria in the mother cells, whereas daughters of the sir2 mutant had fragmented mitochondria at all ages.
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Affiliation(s)
- Yuen T Lam
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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24
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Sarup P, Sørensen P, Loeschcke V. Flies selected for longevity retain a young gene expression profile. AGE (DORDRECHT, NETHERLANDS) 2011; 33:69-80. [PMID: 20607427 PMCID: PMC3063640 DOI: 10.1007/s11357-010-9162-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 06/15/2010] [Indexed: 05/29/2023]
Abstract
We investigated correlated responses in the transcriptomes of longevity-selected lines of Drosophila melanogaster to identify pathways that affect life span in metazoan systems. We evaluated the gene expression profile in young, middle-aged, and old male flies, finding that 530 genes were differentially expressed between selected and control flies when measured at the same chronological age. The longevity-selected flies consistently showed expression profiles more similar to control flies one age class younger than control flies of the same age. This finding is in accordance with a younger gene expression profile in longevity-selected lines. Among the genes down-regulated in longevity-selected lines, we found a clear over-representation of genes involved in immune functions, supporting the hypothesis of a life-shortening effect of an overactive immune system, known as inflammaging. We judged the physiological age as the level of cumulative mortality. Eighty-four genes were differentially expressed between the control and longevity-selected lines at the same physiological age, and the overlap between the same chronological and physiological age gene lists included 40 candidate genes for increased longevity. Among these candidates were genes with roles in starvation resistance, immune response regulation, and several that have not yet been linked to longevity. Investigating these genes would provide new knowledge of the pathways that affect life span in invertebrates and, potentially, mammals.
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Affiliation(s)
- Pernille Sarup
- Aarhus Centre for Environmental Stress Research (ACES), Department of Biological Sciences, Aarhus University, Ny Munkegade 114, Aarhus C, Denmark.
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25
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Anversa P, Olivetti G. Cellular Basis of Physiological and Pathological Myocardial Growth. Compr Physiol 2011. [DOI: 10.1002/cphy.cp020102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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26
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Klijs B, Mackenbach JP, Kunst AE. Disability occurrence and proximity to death. Disabil Rehabil 2010; 32:1733-41. [PMID: 20373858 DOI: 10.3109/09638281003746049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE This paper aims to assess whether disability occurrence is related more strongly to proximity to death than to age. METHOD Self reported disability and vital status were available from six annual waves and a subsequent 12-year mortality follow-up of the Dutch GLOBE longitudinal study. Logit and Poisson regression methods were used to study associations of disability occurrence with age and with proximity to death. RESULTS For disability in activities of daily living (ADL), regression models with proximity to death had better goodness of fit than models with age. With approaching death, the odds for ADL disability prevalence and incidence rates increased 20.0% and 18.9% per year, whereas severity increased 4.1% per year. For the ages younger than 60, 60-69 and older than 70 years, the odds for ADL disability prevalence increased 6.4%, 16.0% and 23.0% per year. Among subjects with asthma/chronic obstructive pulmonary disease, heart disease and diabetes increases were 25.1%, 19.5% and 22.7% per year. Functional impairments were more strongly related to age. CONCLUSIONS The strong association of (ADL) disability occurrence with proximity to death implies that a substantial part of the disability burden may shift to older ages with further increases in life expectancy.
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Affiliation(s)
- Bart Klijs
- Department of Public Health, Erasmus MC, Rotterdam, The Netherlands.
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27
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Jazwinski SM, Kim S, Dai J, Li L, Bi X, Jiang JC, Arnold J, Batzer MA, Walker JA, Welsh DA, Lefante CM, Volaufova J, Myers L, Su LJ, Hausman DB, Miceli MV, Ravussin E, Poon LW, Cherry KE, Welsch MA. HRAS1 and LASS1 with APOE are associated with human longevity and healthy aging. Aging Cell 2010; 9:698-708. [PMID: 20569235 DOI: 10.1111/j.1474-9726.2010.00600.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The search for longevity-determining genes in human has largely neglected the operation of genetic interactions. We have identified a novel combination of common variants of three genes that has a marked association with human lifespan and healthy aging. Subjects were recruited and stratified according to their genetically inferred ethnic affiliation to account for population structure. Haplotype analysis was performed in three candidate genes, and the haplotype combinations were tested for association with exceptional longevity. An HRAS1 haplotype enhanced the effect of an APOE haplotype on exceptional survival, and a LASS1 haplotype further augmented its magnitude. These results were replicated in a second population. A profile of healthy aging was developed using a deficit accumulation index, which showed that this combination of gene variants is associated with healthy aging. The variation in LASS1 is functional, causing enhanced expression of the gene, and it contributes to healthy aging and greater survival in the tenth decade of life. Thus, rare gene variants need not be invoked to explain complex traits such as aging; instead rare congruence of common gene variants readily fulfills this role. The interaction between the three genes described here suggests new models for cellular and molecular mechanisms underlying exceptional survival and healthy aging that involve lipotoxicity.
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Affiliation(s)
- S Michal Jazwinski
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
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28
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Abstract
We review the definitions, predictors, and biobehavioral determinants of successful aging, as well as the evidence for and mechanisms of underlying selected interventions to enhance cognitive and emotional health in older adults. Defining successful aging has proven difficult, with discrepancies seen among biomedical, psychological, and lay perspectives. Although consensus is lacking, a number of studies have examined the genetic, lifestyle, and social determinants of operationalized determinants of successful aging; qualitative examinations of the meaning of the construct have also been conducted. The determinants coincide with fundamental aspects of aging. Recent clinical trials suggest that caloric restriction, physical activity, cognitive intervention, stress reduction, and social programs may enhance cognitive and emotional health in older people.
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Affiliation(s)
- Colin Depp
- Sam and Rose Stein Institute for Research on Aging, Department of Psychiatry, University of California, San Diego, La Jolla, California 92093
| | - Ipsit V. Vahia
- Sam and Rose Stein Institute for Research on Aging, Department of Psychiatry, University of California, San Diego, La Jolla, California 92093
| | - Dilip Jeste
- Sam and Rose Stein Institute for Research on Aging, Department of Psychiatry, University of California, San Diego, La Jolla, California 92093
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29
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Greve W, Bjorklund DF. The Nestor effect: Extending evolutionary developmental psychology to a lifespan perspective. DEVELOPMENTAL REVIEW 2009. [DOI: 10.1016/j.dr.2009.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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30
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Liu J, Zhawar VK, Kaur G, Kaur GP, Deriel JK, Kandpal RP, Athwal RS. Chromosome 6 encoded RNaseT2 protein is a cell growth regulator. J Cell Mol Med 2009; 14:1146-55. [PMID: 19382914 PMCID: PMC3822751 DOI: 10.1111/j.1582-4934.2009.00749.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We have previously shown by chromosome transfer technique that chromosome 6 alters the phenotype of a variety of tumour cells and SV40 immortalized cells. We present here the phenotypic effects of the ectopic expression of RNaseT2, a highly conserved ribonuclease encoded by chromosome 6q27, in SV40 immortalized cell lines. We contrast our findings with those reported for ovarian carcinoma cell lines and an SV40 immortalized cell line transfected with RNaseT2. Although RNaseT2 expression is elevated in normal diploid fibroblasts approaching senescence (passage 64), forced expression of the gene in immortalized cells does not cause them to senesce. A significant reduction was observed in colony forming efficiency, anchorage independence and growth rate of cells transfected with RNaseT2. The levels of transcripts involved in Akt signalling pathway, cell cycle control and pathways related to cell proliferation decreased 2–10-folds in SV40 immortalized cells in response to RNaseT2 expression. Interestingly, some immortalized cells expressed alternatively spliced transcript variants instead of the full-length RNaseT2 transcript. Our results are consistent with the conclusion that RNaseT2 is a cell growth regulator and it does not induce senescence in SV40 immortalized cell lines.
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Affiliation(s)
- Jinglan Liu
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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31
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Brown-Borg HM. Hormonal control of aging in rodents: the somatotropic axis. Mol Cell Endocrinol 2009; 299:64-71. [PMID: 18674587 PMCID: PMC4390024 DOI: 10.1016/j.mce.2008.07.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 04/20/2008] [Accepted: 07/03/2008] [Indexed: 01/08/2023]
Abstract
There is a growing body of literature focusing on the somatotropic axis and regulation of aging and longevity. Many of these reports derive data from multiple endocrine mutants, those that exhibit both elevated growth hormone (GH) and insulin-like growth factor I (IGF-1) or deficiencies in one or both of these hormones. In general, both spontaneous and genetically engineered GH and IGF-1 deficiencies have lead to small body size, delayed development of sexual maturation and age-related pathology, and life span extension. In contrast, characteristics of high circulating GH included larger body sizes, early puberty and reproductive senescence, increased cancer incidence and reduced life span when compared to wild-type animals with normal plasma hormone concentrations. This information, along with that found in multiple other species, implicates this anabolic pathway as the major regulator of longevity in animals.
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Affiliation(s)
- Holly M Brown-Borg
- Department of Pharmacology, Physiology & Therapeutics, University of North Dakota School of Medicine & Health Sciences, 501 North Columbia Road, Grand Forks, ND 58203, United States.
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32
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Strub GM, Depcrynski A, Elmore LW, Holt SE. Recovery from stress is a function of age and telomere length. Cell Stress Chaperones 2008; 13:475-82. [PMID: 18491040 PMCID: PMC2673929 DOI: 10.1007/s12192-008-0047-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/07/2008] [Accepted: 04/14/2008] [Indexed: 10/22/2022] Open
Abstract
Cells are constantly exposed to a wide variety of stimuli and must be able to mount appropriate physiological responses in order to maintain proper form and function. Cells from every organism have evolved highly conserved mechanisms to cope with environmental changes, including the widely studied heat shock response (HSR), which is induced by a variety of cellular stresses such as heavy metal ion exposure. It has long been known that as organisms and individual cells age, their ability to appropriately cope with environmental stress is attenuated. Here, we examine the ability of two heavy metal ions (ZnCl(2), SnCl(2)) to induce the HSR in human fibroblasts by assessing the expression of heat shock proteins (Hsp90, Hsp70, and p23) and the ability of the cells to recover over time. We demonstrate that the induction and recovery of chaperone levels is attenuated with age and that cells immortalized with the human telomerase reverse transcriptase component of the telomerase enzyme do not attenuate their HSR as their replicative age increases. Our data suggest that the recovery of normal human cells from an HSR is related in part to age and the cell's overall telomere length.
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Affiliation(s)
- Graham M. Strub
- Department of Biochemistry, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298-0662 USA
| | - Amy Depcrynski
- Department of Human and Molecular Genetics, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298-0662 USA
| | - Lynne W. Elmore
- Department of Pathology, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298-0662 USA
- Massey Cancer Center, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298–0662 USA
| | - Shawn E. Holt
- Department of Human and Molecular Genetics, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298-0662 USA
- Department of Pathology, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298-0662 USA
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298–0662 USA
- Massey Cancer Center, Medical College of Virginia Campus at Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298–0662 USA
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Fahey GC, Barry KA, Swanson KS. Age-Related Changes in Nutrient Utilization by Companion Animals. Annu Rev Nutr 2008; 28:425-45. [DOI: 10.1146/annurev.nutr.28.061807.155325] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- George C. Fahey
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, Illinois 61801; , ,
| | - Kathleen A. Barry
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, Illinois 61801; , ,
| | - Kelly S. Swanson
- Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, Illinois 61801; , ,
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Abstract
Much attention has been focused on the hypothesis that oxidative damage plays a part in cellular and organismal aging. Oxygen is initially converted to superoxide anion (O2), one of the reactive oxygen species (ROS), by electrons mainly leaked from complex III in the electron transport system present in mitochondria, where it is the major endogenous source of ROS. We have shown that a mutation in a subunit, cytochrome b large subunit (SDHC), of complex II, also results in increasing O2 production and therefore leads to apoptosis and precocious aging in Caenorhabditis elegans. Recently, individuals with an inherited propensity for vascularized head and neck tumors (ie, paragangliomas) have been shown to possess one of several mutations in complex II. To further explore the role of oxidative stress from mitochondria on apoptosis and cancer, we established a transgenic cell line with a point mutation at the ubiquinone binding region in the SDHC gene. As expected, this mutation increased O2 production from complex II and led to excess apoptosis. Moreover, a significant fraction of the surviving cells from the apoptosis were transformed, as evidenced by increased tumor formation, after injection into mice. Oxidative stress results in damage to the cellular components including mitochondria and therefore leads to apoptosis. Furthermore, oxidative stress seems to cause mutations in DNA and leads to cancer. It is suggested that oxidative stress from mitochondria plays an important role in apoptosis, which leads to precocious aging and cancer.
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Affiliation(s)
- Naoaki Ishii
- Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan.
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35
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Lushchak VI. Free radical oxidation of proteins and its relationship with functional state of organisms. BIOCHEMISTRY (MOSCOW) 2007; 72:809-27. [DOI: 10.1134/s0006297907080020] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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36
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Abstract
Increasing numbers of very elderly patients require surgery. Elderly patients are at increased risk of perioperative morbidity and mortality because of the high incidence of co-existing age-related diseases. With greater experience, outcomes from major operations in octogenarians have improved. The increased risks of surgery in the elderly must, however, be individually weighed against the benefits to be gained from symptom relief and improved quality of life.
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Affiliation(s)
- B T Veering
- Department of Anaesthesiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
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37
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Pardon MC. Stress and ageing interactions: A paradox in the context of shared etiological and physiopathological processes. ACTA ACUST UNITED AC 2007; 54:251-73. [PMID: 17408561 DOI: 10.1016/j.brainresrev.2007.02.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 02/15/2007] [Accepted: 02/22/2007] [Indexed: 12/18/2022]
Abstract
Gerontology has made considerable progress in the understanding of the mechanisms underlying the ageing process and age-related neurodegenerative disorders. However, ways to improve quality of life in the elderly remain to be elucidated. It is now clear that stress and the ageing process share a number of underlying mechanisms bound in a very close, if not indissociable, relationship. The ageing process is regulated by the factors underlying the ability to adjust to stress, whilst stress has an influence on the life span and the quality of ageing. In addition, the ability to cope with stress in adulthood predicts life expectancy and quality of life at senescence. The ageing process and stress also share several common mechanisms, particularly in relation to the energy factor. Stress consumes energy and ageing may be considered as a cost of the energy expended to deal with the stressors to which the body is exposed throughout its lifetime. This suggests that the ageing process is associated with and/or a consequence of a long-lasting activation of the major stress responsive systems. However, despite common features, the interaction between stress and the ageing process gives rise to some paradoxes. Stress can either diminish or exacerbate the ageing process just as the ageing process can worsen or counter the effects of stress. There has been little attempt to understand how ageing and stress might interact to promote "successful" or pathological ageing. A key factor in this respect is the individual's ability to adapt to stress. Viewed from this angle, the quality of life of aged subjects may be improved through therapy designed to improve the tolerance to stress.
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Affiliation(s)
- Marie-Christine Pardon
- Institute of Neuroscience, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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38
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Abstract
Multiple biological and environmental factors impact the life span of an organism. The endocrine system is a highly integrated physiological system in mammals that regulates metabolism, growth, reproduction, and response to stress, among other functions. As such, this pervasive entity has a major influence on aging and longevity. The growth hormone, insulin-like growth factor-1 and insulin pathways have been at the forefront of hormonal control of aging research in the last few years. Other hormones, including those from the thyroid and reproductive system have also been studied in terms of life span regulation. The relevance of these hormones to human longevity remains to be established, however the evidence from other species including yeast, nematodes, and flies suggest that evolutionarily well-conserved mechanisms are at play and the endocrine system is a key determinant.
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Affiliation(s)
- Holly M Brown-Borg
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58203, USA.
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39
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Parsons PA. The ecological stress theory of aging and hormesis: an energetic evolutionary model. Biogerontology 2007; 8:233-42. [PMID: 17473992 DOI: 10.1007/s10522-007-9080-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 12/30/2006] [Indexed: 10/23/2022]
Abstract
Free-living organisms normally struggle to exist in harsh environments that are nutritionally and energetically inadequate, where evolutionary adaptation is challenged by internal stresses within organisms and external stresses from the environment. The incorporation of environmental variables into aging theories such as the free-radical and metabolic rate/oxidative stress theories, is the basis of the ecological stress theory of aging and hormesis. Environmental variation from optimum to lethal extremes gives a fitness-stress continuum, where energetic efficiency, or fitness, is inversely related to stress level; in the evolutionary context survival is a more direct measure of fitness for assessing aging than is lifespan. On this continuum, the hormetic zone is in the optimum region, while aging emphasizes survival towards lethal extremes. At the limits of survival, a convergence of physiological and genetical processes is expected under accumulating stress from Reactive Oxygen Species, ROS. Limited ecologically-oriented studies imply that major genes are important towards limits of survival compared with the hormetic zone. Future investigations could usefully explore outlier populations physiologically and genetically, since there is the likelihood that genetic variability may be lower in those cohorts managing to survive to extremely advanced ages as found in highly stressed ecological outlier populations. If so, an evolutionary explanation of the mortality-rate decline typical of cohorts of the extremely old emerges. In summary, an energetic evolutionary approach produces a general aging theory which automatically incorporates hormesis, since the theory is based on a fitness-stress continuum covering the whole range of possible abiotic environments of natural populations.
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40
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Erickson RR, Dunning LM, Holtzman JL. The effect of aging on the chaperone concentrations in the hepatic, endoplasmic reticulum of male rats: the possible role of protein misfolding due to the loss of chaperones in the decline in physiological function seen with age. J Gerontol A Biol Sci Med Sci 2006; 61:435-43. [PMID: 16720739 DOI: 10.1093/gerona/61.5.435] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The endoplasmic reticulum (ER) chaperones are highly conserved proteins that catalyze the posttranslational processing of all secretory and membrane proteins. Our studies suggest that chaperone declines are one of the two central defects in Alzheimer's disease. We propose that similar declines in other organ systems underlie the physiological deficits of aging. Rats were maintained in a colony from age 21 days to death. Animals were killed at regular intervals, and hepatic, ER chaperone contents were determined by immunoblotting. ERp55, ERp57, ERp72, BiP, and calnexin constitutive levels declined 30%-50% with age. Calreticulin was unaffected. BiP (also known as GRP78), ERp55, and ERp57 showed marked swings with peaks occurring in midwinter and midsummer. This cyclics declined 73% with age. Considering the role of the ER chaperones in membrane and secretory protein posttranslational processing, these data support the concept that their loss could lead to many of the physiological declines associated with aging.
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Affiliation(s)
- Richard R Erickson
- Department of Pharmacology, University of Minnesota, and Research, Veterans Affairs Medical Center, 4710 Girard Ave. S., Minneapolis, MN 55419, USA
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41
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Becker B, Holtgrefe S, Jung S, Wunrau C, Kandlbinder A, Baier M, Dietz KJ, Backhausen JE, Scheibe R. Influence of the photoperiod on redox regulation and stress responses in Arabidopsis thaliana L. (Heynh.) plants under long- and short-day conditions. PLANTA 2006; 224:380-93. [PMID: 16435132 DOI: 10.1007/s00425-006-0222-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Accepted: 12/14/2005] [Indexed: 05/06/2023]
Abstract
Arabidopsis thaliana L. (Heynh.) plants were grown in low light (150 micromol photons m(-2) s(-1) and 20 degrees C) either in short days (7.5 h photoperiod) or long days (16 h photoperiod), and then transferred into high light and low temperature (350-800 micromol photons m(-2) s(-1) at 12 degrees C). Plants grown in short days responded with a rapid increase in NADP-malate dehydrogenase (EC 1.1.1.82) activation state. However, persisting overreduction revealed a new level of regulation of the malate valve. Activity measurements and Northern-blot analyses indicated that NADP-malate dehydrogenase transcript and protein levels increased within a few hours. Using macroarrays, additional changes in gene expression were identified. Transcript levels for several enzymes of glutathione metabolism and of some photosynthetic genes increased. The cellular glutathione level increased, but its redox state remained unchanged. A different situation was observed in plants grown in long-day conditions. Neither NADP-malate dehydrogenase nor glutathione content changed, but the expression of several antioxidative enzymes increased strongly. We conclude that the endogenous systems that measure day length interact with redox regulation, and override the interpretation of the signals, i.e. they redirect redox-mediated acclimation signals to allow for more efficient light usage and redox poising in short days to systems for the prevention of oxidative damages when grown under long-day conditions.
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Affiliation(s)
- Beril Becker
- Pflanzenphysiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, 49069, Osnabrück, Germany
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42
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Rollo CD. Radiation and the regulatory landscape of neo2-Darwinism. Mutat Res 2006; 597:18-31. [PMID: 16414092 DOI: 10.1016/j.mrfmmm.2005.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Revised: 06/24/2005] [Accepted: 09/14/2005] [Indexed: 05/06/2023]
Abstract
Several recently revealed features of eukaryotic genomes were not predicted by earlier evolutionary paradigms, including the relatively small number of genes, the very large amounts of non-functional code and its quarantine in heterochromatin, the remarkable conservation of many functionally important genes across relatively enormous phylogenetic distances, and the prevalence of extra-genomic information associated with chromatin structure and histone proteins. All of these emphasize a paramount role for regulatory evolution, which is further reinforced by recent perspectives highlighting even higher-order regulation governing epigenetics and development (EVO-DEVO). Modern neo2-Darwinism, with its emphasis on regulatory mechanisms and regulatory evolution provides new vision for understanding radiation biology, particularly because free radicals and redox states are central to many regulatory mechanisms and free radicals generated by radiation mimic and amplify endogenous signalling. This paper explores some of these aspects and their implications for low-dose radiation biology.
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Affiliation(s)
- C David Rollo
- Department of Biology, Life Sciences Building, 1280 Main St. West, Hamilton, Ont., Canada L8S 4K1.
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43
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Abstract
Women are living longer today, composing the majority of persons aged 65 and over. Their dermatologic needs are unique and cross ethnic and cultural lines. With this increased life expectancy comes an increased occurrence of skin disorders. The identification and treatment of these conditions is important for the practicing clinician. This article reviews some of the more common dermatologic disorders of older women, and discusses the latest treatments and issues facing this geriatric population.
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Affiliation(s)
- Wendy E Roberts
- Loma Linda University Medical School, Loma Linda, and Desert Dermatology Medical Associates, 39-700 Bob Hope Drive, Suite 115, Rancho Mirage, CA 92270, USA.
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44
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Affiliation(s)
- Holly M Brown-Borg
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks 58203, USA
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Zhang C, Wang J, Liu G, Chen Q. Effect of the Chinese traditional medicine "Bushen Yinao Pian" on the cerebral gene expression of the senescence-accelerated mouse prone 8/ta. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2005; 33:639-50. [PMID: 16173537 DOI: 10.1142/s0192415x05003235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The effect of Chinese traditional medicine "Bushen Yinao Pian," a complex prescription used for anti-aging, on the cerebral gene expression of the senescence-accelerated mouse prone 8/Ta (SAMP8/Ta) had been studied with messenger ribonuclear acids reverse transcription differential display polymerase chain reaction (mRNA DDRT-PCR). Eight differential displayed bands had been discerned and sequenced. The sequences of those fragments are matched to adipocyte-specific protein-5; low density lipoprotein receptor-related protein associated protein-1; reticulon-3; cysteine and histidine-rich domain (CHORD)-containing, zinc-binding protein-1; cytochrome c oxidase subunit-2 (Cox-2); cytochrome c gene, MC1; DNA sequence from clone RP23-72M11 on chromosome X, respectively and a novel sequence fragment. Most of these genes are aging-related. It can be proved that the "Bushen Yinao Pian" truly has anti-aging function.
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Affiliation(s)
- Chong Zhang
- The Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100080, China
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Abstract
This review covers the application of mass spectrometric techniques to aging research. Modern proteomic strategies will be discussed as well as the targeted analysis of specific proteins for the correlation of post-translational modifications with protein function. Selected examples will show both the power and also current limitations of the respective techniques. Experimental results and strategies are discussed in view of current theories of the aging process.
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Affiliation(s)
- Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Avenue, Lawrence, Kansas 66047, USA
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47
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Jazwinski SM. Rtg2 protein: at the nexus of yeast longevity and aging. FEMS Yeast Res 2005; 5:1253-9. [PMID: 16099222 DOI: 10.1016/j.femsyr.2005.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 06/28/2005] [Accepted: 07/01/2005] [Indexed: 10/25/2022] Open
Abstract
Firm support for the notion that metabolism and particularly mitochondrial metabolism plays a significant role in aging has been gathered in studies on yeast. As in other organisms, mitochondria contribute to aging through their propensity to generate reactive oxygen species. There is more to the involvement of mitochondria in aging than this, however. Mitochondrial dysfunction, which accumulates during aging, triggers the retrograde response, an intracellular signaling pathway that activates genes that compensate for this dysfunction. A key signaling protein in this pathway is the Rtg2 protein. Recent studies have provided evidence that this protein lies at the nexus of the four major processes that are involved in aging in yeast and in other organisms; namely, metabolism, stress resistance, chromatin-dependent gene regulation, and genome stability. The details of this central role of Rtg2 protein explain the delicate balance between longevity and aging, which ultimately must tip towards the latter. Phenomena that resemble the retrograde response appear to exist in human cells, with both common and cell type-specific gene expression changes as the output.
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Affiliation(s)
- S Michal Jazwinski
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1901 Perdido St., P.O. Box P7-2, New Orleans, LA 70112, USA.
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Agarwal S, Sharma S, Agrawal V, Roy N. Caloric restriction augments ROS defense in S. cerevisiae, by a Sir2p independent mechanism. Free Radic Res 2005; 39:55-62. [PMID: 15875812 DOI: 10.1080/10715760400022343] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Aging is associated with increased production of reactive oxygen species (ROS) and oxidation-induced damage to intracellular structures and membranes. Caloric restriction (CR) has been demonstrated to delay aging in a variety of species. Although the mechanisms of CR remain to be clearly elucidated, reductions in oxidative damage have been shown to increase lifespan in several model systems. Contrary to the general belief that ROS production is reduced in CR, this article provides evidence that not only oxygen consumption but ROS production is enhanced in the calorie restricted condition. To understand the biological mechanism underlying the anti aging action of CR, the role of scavenging enzymes was studied. It was found that super oxide dismutase (SOD1 and SOD2), catalase and glutathione peroxidase (GPx) all are over expressed in CR. We further investigated the role of Sir2, a potential effector of CR response in the activation of scavenging enzymes. No marked difference was found in CR mediated activation of SOD and catalase in the absence of Sir2. Our results suggest that in CR scavenging enzymes are activated by a Sir2 independent manner.
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Affiliation(s)
- Shruti Agarwal
- Department of Biotechnology, National Institute of Pharmaceutical Education, and Research Sector 67, S.A.S. Nagar, Punjab 160062, India
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Jazwinski SM. The retrograde response links metabolism with stress responses, chromatin-dependent gene activation, and genome stability in yeast aging. Gene 2005; 354:22-7. [PMID: 15890475 DOI: 10.1016/j.gene.2005.03.040] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Accepted: 03/25/2005] [Indexed: 10/25/2022]
Abstract
Yeast can be used as a model to understand the impact mitochondria have on aging in higher organisms. Mitochondrial dysfunction increases with replicative age in yeast, and this is associated with the induction of the retrograde response. This intracellular signaling pathway from the mitochondrion to the nucleus results in changes in the expression of metabolic and stress genes, which adapt the yeast cell to the loss of tricarboxylic acid cycle activity by providing alternate anaplerotic sources of biosynthetic precursors. The induction of the retrograde response increases longevity. Paradoxically, it also leads to the production of extrachromosomal ribosomal DNA circles, which cause yeast demise. The deleterious effects of these circles are mitigated by the retrograde response, which increases longevity in part due to this effect and partly due to other activities. Rtg2p is the retrograde signal transducer proximal to the mitochondrion, and it interacts with several proteins in relaying the retrograde signal to the transcription factor Rtg1p-Rtg3p. Rtg2p also suppresses ribosomal DNA circle production. When it is engaged in retrograde signaling, it cannot fulfill the latter role. The SAGA-like SLIK complex is one of the protein complexes in which Rtg2p has been found. This histone acetyltransferase, transcriptional co-activator complex contains Gcn5p, and it potentiates the activation of retrograde responsive genes. SLIK complex integrity, and in particular Gcn5p, are needed for retrograde response extension of life span. Thus, the retrograde response through SLIK links metabolism, stress responses, chromatin-dependent gene regulation, and genome stability in yeast aging. Gene regulatory phenomena akin to the retrograde response also operate in human cells, which display both common and cell-type specific changes in gene expression on loss of mitochondrial function.
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Affiliation(s)
- S Michal Jazwinski
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1901 Perdido St., Box P7-2, New Orleans, LA 70112, USA.
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Kim S, Ohkuni K, Couplan E, Jazwinski SM. The histone acetyltransferase GCN5 modulates the retrograde response and genome stability determining yeast longevity. Biogerontology 2005; 5:305-16. [PMID: 15547318 DOI: 10.1007/s10522-004-2568-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transcriptional silencing decreases at both subtelomeric and silent mating-type loci and increases at the ribosomal DNA locus during the replicative life span of the yeast Saccharomyces cerevisiae . Evidence exists that epigenetic changes in the regulatory state of chromatin may be a causal factor in determining yeast longevity and that histone deacetylases play a role. The significance of histone acetylation has been examined here in more detail. Deletion of the histone acetyltransferase gene GCN5 suppressed the extension of replicative life span afforded by the induction of the retrograde response, which signals mitochondrial dysfunction and leads to changes in nuclear gene expression. It was difficult to ascribe this effect to changes in transcriptional silencing in any of the three known types of heterochromatin. However, a promoter related effect was uncovered by the participation of GCN5 in the induction of the retrograde response. Gcn5p and the retrograde signal transducer Rtg2p are components of the histone acetyltransferase coactivator complex SLIK. Rtg2p blocks the production of extrachromosomal ribosomal DNA circles when it is not engaged in transmission of the retrograde signal. Deletion of GCN5 , which disrupts the integrity of SLIK, suppressed circle accumulation. The results indicate that Gcn5p and SLIK impact the interplay between the retrograde response signal and Rtg2p with consequences for the induction of the response and circle production. Rtg2p and Gcn5p in the SLIK complex link metabolism to stress responses, chromatin-dependent gene regulation, and genome stability in yeast aging.
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Affiliation(s)
- Sangkyu Kim
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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