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Dai X, Guo X. Decoding and rejuvenating human ageing genomes: Lessons from mosaic chromosomal alterations. Ageing Res Rev 2021; 68:101342. [PMID: 33866012 DOI: 10.1016/j.arr.2021.101342] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 01/10/2023]
Abstract
One of the most curious findings emerged from genome-wide studies over the last decade was that genetic mosaicism is a dominant feature of human ageing genomes. The clonal dominance of genetic mosaicism occurs preceding the physiological and physical ageing and associates with propensity for diseases including cancer, Alzheimer's disease, cardiovascular disease and diabetes. These findings are revolutionizing the ways biologists thinking about health and disease pathogenesis. Among all mosaic mutations in ageing genomes, mosaic chromosomal alterations (mCAs) have the most significant functional consequences because they can produce intercellular genomic variations simultaneously involving dozens to hundreds or even thousands genes, and therefore have most profound effects in human ageing and disease etiology. Here, we provide a comprehensive picture of the landscapes, causes, consequences and rejuvenation of mCAs at multiple scales, from cell to human population, by reviewing data from cytogenetic, genetic and genomic studies in cells, animal models (fly and mouse) and, more frequently, large-cohort populations. A detailed decoding of ageing genomes with a focus on mCAs may yield important insights into the genomic architecture of human ageing, accelerate the risk stratification of age-related diseases (particularly cancers) and development of novel targets and strategies for delaying or rejuvenating human (genome) ageing.
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Affiliation(s)
- Xueqin Dai
- School of Life Sciences, Yunnan Normal University, Kunming, Yunnan, 650500, China
| | - Xihan Guo
- School of Life Sciences, Yunnan Normal University, Kunming, Yunnan, 650500, China; The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, Yunnan, 650500, China; Yunnan Environmental Mutagen Society, Kunming, Yunnan, 650500, China.
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2
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Pasyukova EG, Symonenko AV, Rybina OY, Vaiserman AM. Epigenetic enzymes: A role in aging and prospects for pharmacological targeting. Ageing Res Rev 2021; 67:101312. [PMID: 33657446 DOI: 10.1016/j.arr.2021.101312] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/05/2021] [Accepted: 02/25/2021] [Indexed: 02/06/2023]
Abstract
The development of interventions aimed at improving healthspan is one of the priority tasks for the academic and public health authorities. It is also the main objective of a novel branch in biogerontological research, geroscience. According to the geroscience concept, targeting aging is an effective way to combat age-related disorders. Since aging is an exceptionally complex process, system-oriented integrated approaches seem most appropriate for such an interventional strategy. Given the high plasticity and adaptability of the epigenome, epigenome-targeted interventions appear highly promising in geroscience research. Pharmaceuticals targeted at mechanisms involved in epigenetic control of gene activity are actively developed and implemented to prevent and treat various aging-related conditions such as cardiometabolic, neurodegenerative, inflammatory disorders, and cancer. In this review, we describe the roles of epigenetic mechanisms in aging; characterize enzymes contributing to the regulation of epigenetic processes; particularly focus on epigenetic drugs, such as inhibitors of DNA methyltransferases and histone deacetylases that may potentially affect aging-associated diseases and longevity; and discuss possible caveats associated with the use of epigenetic drugs.
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Affiliation(s)
- Elena G Pasyukova
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute", Kurchatov Sq. 2, Moscow, 123182, Russia
| | - Alexander V Symonenko
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute", Kurchatov Sq. 2, Moscow, 123182, Russia
| | - Olga Y Rybina
- Institute of Molecular Genetics of National Research Centre "Kurchatov Institute", Kurchatov Sq. 2, Moscow, 123182, Russia; Federal State Budgetary Educational Institution of Higher Education «Moscow Pedagogical State University», M. Pirogovskaya Str. 1/1, Moscow, 119991, Russia
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3
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van den Boogaard WMC, van den Heuvel-Eibrink MM, Hoeijmakers JHJ, Vermeij WP. Nutritional Preconditioning in Cancer Treatment in Relation to DNA Damage and Aging. ANNUAL REVIEW OF CANCER BIOLOGY 2021; 5:161-179. [PMID: 35474917 PMCID: PMC9037985 DOI: 10.1146/annurev-cancerbio-060820-090737] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dietary restriction (DR) is the most successful nutritional intervention for extending lifespan and preserving health in numerous species. Reducing food intake triggers a protective response that shifts energy resources from growth to maintenance and resilience mechanisms. This so-called survival response has been shown to particularly increase life- and health span and decrease DNA damage in DNA repair-deficient mice exhibiting accelerated aging. Accumulation of DNA damage is the main cause of aging, but also of cancer. Moreover, radiotherapies and most chemotherapies are based on damaging DNA, consistent with their ability to induce toxicity and accelerate aging. Since fasting and DR decrease DNA damage and its effects, nutritional preconditioning holds promise for improving (cancer) therapy and preventing short- and long-term side effects of anticancer treatments. This review provides an overview of the link between aging and cancer, highlights important preclinical studies applying such nutritional preconditioning, and summarizes the first clinical trials implementing nutritional preconditioning in cancer treatment.
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Affiliation(s)
- Winnie M C van den Boogaard
- Genome Instability and Nutrition Research Group, Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands.,Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Marry M van den Heuvel-Eibrink
- Pediatric Oncology Translational Research Group, Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | - Jan H J Hoeijmakers
- Genome Instability and Nutrition Research Group, Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands.,Oncode Institute, 3521 AL Utrecht, The Netherlands.,Department of Molecular Genetics, Erasmus University Medical Center, 3015 GD Rotterdam, The Netherlands.,CECAD Forschungszentrum, University of Cologne, 50931 Cologne, Germany
| | - Wilbert P Vermeij
- Genome Instability and Nutrition Research Group, Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands.,Oncode Institute, 3521 AL Utrecht, The Netherlands
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Chen Y, Geng A, Zhang W, Qian Z, Wan X, Jiang Y, Mao Z. Fight to the bitter end: DNA repair and aging. Ageing Res Rev 2020; 64:101154. [PMID: 32977059 DOI: 10.1016/j.arr.2020.101154] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
DNA carries the genetic information that directs complex biological processes; thus, maintaining a stable genome is critical for individual growth and development and for human health. DNA repair is a fundamental and conserved mechanism responsible for mending damaged DNA and restoring genomic stability, while its deficiency is closely related to multiple human disorders. In recent years, remarkable progress has been made in the field of DNA repair and aging. Here, we will extensively discuss the relationship among DNA damage, DNA repair, aging and aging-associated diseases based on the latest research. In addition, the possible role of DNA repair in several potential rejuvenation strategies will be discussed. Finally, we will also review the emerging methods that may facilitate future research on DNA repair.
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5
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Hood WR, Williams AS, Hill GE. An Ecologist’s Guide to Mitochondrial DNA Mutations and Senescence. Integr Comp Biol 2019; 59:970-982. [DOI: 10.1093/icb/icz097] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Abstract
Longevity plays a key role in the fitness of organisms, so understanding the processes that underlie variance in senescence has long been a focus of ecologists and evolutionary biologists. For decades, the performance and ultimate decline of mitochondria have been implicated in the demise of somatic tissue, but exactly why mitochondrial function declines as individual’s age has remained elusive. A possible source of decline that has been of intense debate is mutations to the mitochondrial DNA. There are two primary sources of such mutations: oxidative damage, which is widely discussed by ecologists interested in aging, and mitochondrial replication error, which is less familiar to most ecologists. The goal of this review is to introduce ecologists and evolutionary biologists to the concept of mitochondrial replication error and to review the current status of research on the relative importance of replication error in senescence. We conclude by detailing some of the gaps in our knowledge that currently make it difficult to deduce the relative importance of replication error in wild populations and encourage organismal biologists to consider this variable both when interpreting their results and as viable measure to include in their studies.
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Affiliation(s)
- Wendy R Hood
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Ashley S Williams
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Geoffrey E Hill
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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Vaiserman A, Koliada A, Lushchak O. Developmental programming of aging trajectory. Ageing Res Rev 2018; 47:105-122. [PMID: 30059788 DOI: 10.1016/j.arr.2018.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/12/2022]
Abstract
There is accumulating evidence that aging phenotype and longevity may be developmentally programmed. Main mechanisms linking developmental conditions to later-life health outcomes include persistent changes in epigenetic regulation, (re)programming of major endocrine axes such as growth hormone/insulin-like growth factor axis and hypothalamic-pituitary-adrenal axis and also early-life immune maturation. Recently, evidence has also been generated on the role of telomere biology in developmental programming of aging trajectory. In addition, persisting changes of intestinal microbiota appears to be crucially involved in these processes. In this review, experimental and epidemiological evidence on the role of early-life conditions in programming of aging phenotypes are presented and mechanisms potentially underlying these associations are discussed.
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7
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Lichtenstein AV. Genetic Mosaicism and Cancer: Cause and Effect. Cancer Res 2018; 78:1375-1378. [DOI: 10.1158/0008-5472.can-17-2769] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/14/2017] [Accepted: 01/09/2018] [Indexed: 11/16/2022]
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Tombline G, Millen JI, Polevoda B, Rapaport M, Baxter B, Van Meter M, Gilbertson M, Madrey J, Piazza GA, Rasmussen L, Wennerberg K, White EL, Nitiss JL, Goldfarb DS. Effects of an unusual poison identify a lifespan role for Topoisomerase 2 in Saccharomyces cerevisiae. Aging (Albany NY) 2017; 9:68-97. [PMID: 28077781 PMCID: PMC5310657 DOI: 10.18632/aging.101114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/29/2016] [Indexed: 12/17/2022]
Abstract
A progressive loss of genome maintenance has been implicated as both a cause and consequence of aging. Here we present evidence supporting the hypothesis that an age-associated decay in genome maintenance promotes aging in Saccharomyces cerevisiae (yeast) due to an inability to sense or repair DNA damage by topoisomerase 2 (yTop2). We describe the characterization of LS1, identified in a high throughput screen for small molecules that shorten the replicative lifespan of yeast. LS1 accelerates aging without affecting proliferative growth or viability. Genetic and biochemical criteria reveal LS1 to be a weak Top2 poison. Top2 poisons induce the accumulation of covalent Top2-linked DNA double strand breaks that, if left unrepaired, lead to genome instability and death. LS1 is toxic to cells deficient in homologous recombination, suggesting that the damage it induces is normally mitigated by genome maintenance systems. The essential roles of yTop2 in proliferating cells may come with a fitness trade-off in older cells that are less able to sense or repair yTop2-mediated DNA damage. Consistent with this idea, cells live longer when yTop2 expression levels are reduced. These results identify intrinsic yTop2-mediated DNA damage as a potentially manageable cause of aging.
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Affiliation(s)
- Gregory Tombline
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Jonathan I Millen
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Bogdan Polevoda
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Matan Rapaport
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Bonnie Baxter
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Michael Van Meter
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Matthew Gilbertson
- Department of Biopharmaceutical Sciences, UIC College of Pharmacy at Rockford, Rockford, IL 61107, USA
| | - Joe Madrey
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - Gary A Piazza
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - Lynn Rasmussen
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - Krister Wennerberg
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - E Lucile White
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - John L Nitiss
- Department of Biopharmaceutical Sciences, UIC College of Pharmacy at Rockford, Rockford, IL 61107, USA
| | - David S Goldfarb
- Biology Department, University of Rochester, Rochester, NY 14627, USA
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Marongiu F, Serra MP, Fanti M, Cadoni E, Serra M, Laconi E. Regenerative Medicine: Shedding Light on the Link between Aging and Cancer. Cell Transplant 2017; 26:1530-1537. [PMID: 29113461 PMCID: PMC5680953 DOI: 10.1177/0963689717721224] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/17/2017] [Accepted: 02/22/2017] [Indexed: 01/07/2023] Open
Abstract
The evidence linking aging and cancer is overwhelming. Findings emerging from the field of regenerative medicine reinforce the notion that aging and cancer are profoundly interrelated in their pathogenetic pathways. We discuss evidence to indicate that age-associated alterations in the tissue microenvironment contribute to the emergence of a neoplastic-prone tissue landscape, which is able to support the selective growth of preneoplastic cell populations. Interestingly, tissue contexts that are able to select for the growth of preneoplastic cells, including the aged liver microenvironment, are also supportive for the clonal expansion of normal, homotypic, transplanted cells. This suggests that the growth of normal and preneoplastic cells is possibly driven by similar mechanisms, implying that strategies based on principles of regenerative medicine might be applicable to modulate neoplastic disease.
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Affiliation(s)
- Fabio Marongiu
- Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy
| | - Maria Paola Serra
- Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy
| | - Maura Fanti
- Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy
| | - Erika Cadoni
- Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy
| | - Monica Serra
- Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy
| | - Ezio Laconi
- Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy
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Martin LJ, Wong M. Enforced DNA repair enzymes rescue neurons from apoptosis induced by target deprivation and axotomy in mouse models of neurodegeneration. Mech Ageing Dev 2016; 161:149-162. [PMID: 27364693 DOI: 10.1016/j.mad.2016.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/23/2016] [Accepted: 06/26/2016] [Indexed: 02/06/2023]
Abstract
It is unknown whether DNA damage accumulation is an upstream instigator or secondary effect of the cell death process in different populations of adult postmitotic neurons in the central nervous system. In two different mouse models of injury-induced neurodegeneration characterized by relatively synchronous accumulation of mitochondria, oxidative stress, and DNA damage prior to neuronal apoptosis, we enforced the expression of human 8-oxoguanine DNA glycosylase (hOGG1) and human apurinic-apyrimidinic endonuclease-1/Ref1 (hAPE) using recombinant adenoviruses (Ad). Thalamic lateral geniculate neurons and lumbar spinal cord motor neurons were transduced by Ad-hOGG1 and Ad-hAPE injections into the occipital cortex and skeletal muscle, respectively, prior to their target deprivation- and axotomy-induced retrograde apoptosis. Enforced expression of hOGG1 and hAPE in thalamus and spinal cord was confirmed by western blotting and immunohistochemistry. In injured populations of neurons in thalamus and spinal cord, a DNA damage response (DDR) was registered, as shown by localization of phospho-activated p53, Rad17, and replication protein A-32 immunoreactivities, and this DDR was attenuated more effectively by enforced hAPE expression than by hOGG1 expression. Enforced expression of hOGG1 and hAPE significantly protected thalamic neurons and motor neurons from retrograde apoptosis induced by target deprivation and axotomy. We conclude that a DDR response is engaged pre-apoptotically in different types of injured mature CNS neurons and that DNA repair enzymes can regulate the survival of retrogradely dying neurons, suggesting that DNA damage and activation of DDR are upstream mechanisms for this form of adult neurodegeneration in vivo, thus identifying DNA repair as a therapeutic target for neuroprotection.
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Affiliation(s)
- Lee J Martin
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Pathobiology Graduate Training Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Margaret Wong
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Abstract
Free circulating or cell‐free DNA (cfDNA), possibly from dying cells that release their contents into the blood as they break down, have become of major interest as a source for noninvasive diagnostics. Recent work demonstrated the uptake of human cfDNA in mouse cells in vitro and in vivo, accompanied by the activation of a cellular DNA damage response (DDR) and the appearance of apoptotic proteins in the host cells. By acting as a source of mobile genetic elements, cfDNA could be a continuous source of DNA mutagenesis of healthy cells in the body throughout life, promoting progressive cellular aging in vivo. As such, cfDNA may causally contribute to multiple aging‐related diseases, such as cancer, diabetes, and Alzheimer's disease.
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Affiliation(s)
- Silvia Gravina
- Department of Genetics Albert Einstein College of Medicine Bronx NY 10461 USA
| | - John M. Sedivy
- Department of Molecular Biology, Cell Biology and Biochemistry Brown University Providence RI 02912 USA
| | - Jan Vijg
- Department of Genetics Albert Einstein College of Medicine Bronx NY 10461 USA
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Leinwand SG, Yang CJ, Bazopoulou D, Chronis N, Srinivasan J, Chalasani SH. Circuit mechanisms encoding odors and driving aging-associated behavioral declines in Caenorhabditis elegans. eLife 2015; 4:e10181. [PMID: 26394000 PMCID: PMC4577979 DOI: 10.7554/elife.10181] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/24/2015] [Indexed: 12/15/2022] Open
Abstract
Chemosensory neurons extract information about chemical cues from the environment. How is the activity in these sensory neurons transformed into behavior? Using Caenorhabditis elegans, we map a novel sensory neuron circuit motif that encodes odor concentration. Primary neurons, AWCON and AWA, directly detect the food odor benzaldehyde (BZ) and release insulin-like peptides and acetylcholine, respectively, which are required for odor-evoked responses in secondary neurons, ASEL and AWB. Consistently, both primary and secondary neurons are required for BZ attraction. Unexpectedly, this combinatorial code is altered in aged animals: odor-evoked activity in secondary, but not primary, olfactory neurons is reduced. Moreover, experimental manipulations increasing neurotransmission from primary neurons rescues aging-associated neuronal deficits. Finally, we correlate the odor responsiveness of aged animals with their lifespan. Together, these results show how odors are encoded by primary and secondary neurons and suggest reduced neurotransmission as a novel mechanism driving aging-associated sensory neural activity and behavioral declines. DOI:http://dx.doi.org/10.7554/eLife.10181.001 A sense of smell can help animals to find food and detect danger. Odor molecules activate so-called olfactory neurons that relay signals to the brain in the form of nerve impulses. This information is then processed, and the appropriate response is triggered; for example, an animal might move towards the smell of food, or away from the scent of a predator. But how can the activity of olfactory neurons trigger the right behavioral response? Leinwand et al. have now explored the activity of olfactory neurons in a roundworm called C. elegans. The experiments revealed that a food odor activated two olfactory neurons directly, and that each of these ‘primary’ neurons then in turn activated another ‘secondary’ olfactory neuron. This communication between primary and secondary olfactory neurons was essential for worms to respond to the food odor. Further experiments revealed that the primary olfactory neurons send chemical signals, called neurotransmitters and neuropeptides, to communicate with the secondary neurons. Importantly, mutations that blocked this chemical signaling prevented the worms from responding appropriately to the smell of food. Aging animals, including people, often have impaired senses and can therefore find it difficult to identify and respond to odors. Leinwand et al. found that aged worms were no different. Further experiments suggested that aging worms' responses to odor decline because the communication between the primary and secondary olfactory neurons may be impaired with age. When Leinwand et al. strengthened this communication it reversed the effects of aging on the worms' sense of smell. Moreover, the experiments also showed that an animal's performance on the odor task was correlated with its longevity, such that the better performers also lived longer. A challenge for the future is to understand the precise changes that occur at early stages of aging to impair the sense of smell. Future studies could also test if similar combinations of olfactory neurons are needed to trigger certain behavioral responses to odors in young and old mammals. DOI:http://dx.doi.org/10.7554/eLife.10181.002
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Affiliation(s)
- Sarah G Leinwand
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Claire J Yang
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
| | - Daphne Bazopoulou
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, United States
| | - Nikos Chronis
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, United States
| | - Jagan Srinivasan
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, United States
| | - Sreekanth H Chalasani
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
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Maynard S, Fang EF, Scheibye-Knudsen M, Croteau DL, Bohr VA. DNA Damage, DNA Repair, Aging, and Neurodegeneration. Cold Spring Harb Perspect Med 2015; 5:cshperspect.a025130. [PMID: 26385091 DOI: 10.1101/cshperspect.a025130] [Citation(s) in RCA: 228] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Aging in mammals is accompanied by a progressive atrophy of tissues and organs, and stochastic damage accumulation to the macromolecules DNA, RNA, proteins, and lipids. The sequence of the human genome represents our genetic blueprint, and accumulating evidence suggests that loss of genomic maintenance may causally contribute to aging. Distinct evidence for a role of imperfect DNA repair in aging is that several premature aging syndromes have underlying genetic DNA repair defects. Accumulation of DNA damage may be particularly prevalent in the central nervous system owing to the low DNA repair capacity in postmitotic brain tissue. It is generally believed that the cumulative effects of the deleterious changes that occur in aging, mostly after the reproductive phase, contribute to species-specific rates of aging. In addition to nuclear DNA damage contributions to aging, there is also abundant evidence for a causative link between mitochondrial DNA damage and the major phenotypes associated with aging. Understanding the mechanistic basis for the association of DNA damage and DNA repair with aging and age-related diseases, such as neurodegeneration, would give insight into contravening age-related diseases and promoting a healthy life span.
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Affiliation(s)
- Scott Maynard
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Evandro Fei Fang
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Morten Scheibye-Knudsen
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Vilhelm A Bohr
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, DK-2200 Copenhagen, Denmark Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
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SIRT6 represses LINE1 retrotransposons by ribosylating KAP1 but this repression fails with stress and age. Nat Commun 2014; 5:5011. [PMID: 25247314 PMCID: PMC4185372 DOI: 10.1038/ncomms6011] [Citation(s) in RCA: 254] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 08/18/2014] [Indexed: 02/08/2023] Open
Abstract
L1 retrotransposons are an abundant class of transposable elements which pose a threat to genome stability and may play a role in age-related pathologies such as cancer. Recent evidence indicates that L1s become more active in somatic tissues during the course of aging; the mechanisms underlying this phenomenon remain unknown, however. Here we report that the longevity regulating protein, SIRT6, is a powerful repressor of L1 activity. Specifically, SIRT6 binds to the 5′UTR of L1 loci, where it mono-ADP ribosylates the nuclear corepressor protein, KAP1, and facilitates KAP1 interaction with the heterochromatin factor, HP1α, thereby contributing to the packaging of L1 elements into transcriptionally repressive heterochromatin. During the course of aging, and also in response to DNA damage, however, we find that SIRT6 is depleted from L1 loci, allowing for the activation of these previously silenced retroelements.
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Abstract
Natural selection defined by differential survival and reproduction of individuals in populations is influenced by genetic, developmental, and environmental factors operating at every age and stage in human life history: generation of gametes, conception, birth, maturation, reproduction, senescence, and death. Biological systems are built upon a hierarchical organization nesting subcellular organelles, cells, tissues, and organs within individuals, individuals within families, and families within populations, and the latter among other populations. Natural selection often acts simultaneously at more than one level of biological organization and on specific traits, which we define as multilevel selection. Under this model, the individual is a fundamental unit of biological organization and also of selection, imbedded in a larger evolutionary context, just as it is a unit of medical intervention imbedded in larger biological, cultural, and environmental contexts. Here, we view human health and life span as necessary consequences of natural selection, operating at all levels and phases of biological hierarchy in human life history as well as in sociological and environmental milieu. An understanding of the spectrum of opportunities for natural selection will help us develop novel approaches to improving healthy life span through specific and global interventions that simultaneously focus on multiple levels of biological organization. Indeed, many opportunities exist to apply multilevel selection models employed in evolutionary biology and biodemography to improving human health at all hierarchical levels. Multilevel selection perspective provides a rational theoretical foundation for a synthesis of medicine and evolution that could lead to discovering effective predictive, preventive, palliative, potentially curative, and individualized approaches in medicine and in global health programs.
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