1
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Ingelson-Filpula WA, Kadamani KL, Ojaghi M, Pamenter ME, Storey KB. Hypoxia-induced downregulation of RNA m 6A protein machinery in the naked mole-rat heart. Biochimie 2024; 225:125-132. [PMID: 38788827 DOI: 10.1016/j.biochi.2024.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Naked mole-rats, Heterocephalus glaber, are champion hypoxia-tolerant rodents that live under low oxygen conditions in their subterranean burrows. Detrimental effects of low oxygen can be mitigated through metabolic rate depression (MRD), metabolic reorganization, and global downregulation of nonessential cellular processes. Recent research has progressively implicated epigenetic modifications - rapid, reversible changes to gene expression that do not alter the DNA sequence itself - as major players in implementing and maintaining MRD. N6-adenosine (m6A) methylation is the most prevalent mammalian RNA modification and is responsible for pre-mRNA processing and mRNA export from the nucleus. Hence, m6A -mediated conformational changes alter the cellular fate of transcripts. The present study investigated the role of m6A RNA methylation responses to 24 h of hypoxia exposure in H. glaber cardiac tissue. Total protein levels of m6A writers/readers/erasers, m6A demethylase activity, and total m6A quantification were measured under normoxic vs. hypoxic conditions in H. glaber heart. While there was no change in either demethylase activity or total m6A content, many proteins of the m6A pathway were downregulated during hypoxia. Overall, m6A may not be a signature hypoxia-responsive characteristic in H. glaber heart, but downregulation of the protein machinery involved in m6A cycling points to an alternate biological involvement. Further research will explore other forms of RNA modifications and other epigenetic mechanisms to determine the controls on hypoxia endurance in this subterranean mammal.
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Affiliation(s)
- W Aline Ingelson-Filpula
- Affiliation: Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada, K1S 5B6.
| | - Karen L Kadamani
- Biology Department, University of Ottawa, Marie-Curie Pvt, Ottawa, Ontario, K1N 9A7, Canada
| | - Mohammad Ojaghi
- Biology Department, University of Ottawa, Marie-Curie Pvt, Ottawa, Ontario, K1N 9A7, Canada
| | - Matthew E Pamenter
- Biology Department, University of Ottawa, Marie-Curie Pvt, Ottawa, Ontario, K1N 9A7, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Kenneth B Storey
- Affiliation: Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada, K1S 5B6
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2
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Okada D. Application of a mathematical model to clarify the statistical characteristics of a pan-tissue DNA methylation clock. GeroScience 2024; 46:2001-2015. [PMID: 37787856 PMCID: PMC10828133 DOI: 10.1007/s11357-023-00949-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 09/14/2023] [Indexed: 10/04/2023] Open
Abstract
DNA methylation clocks estimate biological age based on DNA methylation profiles. This study developed a mathematical model to describe DNA methylation aging and the establishment of a pan-tissue DNA methylation clock. The model simulates the aging dynamics of DNA methylation profiles based on passive demethylation as well as the process of cross-sectional bulk data acquisition. As a result, this study identified two conditions under which the pan-tissue DNA methylation clock can successfully predict biological age: one condition is that the target tissues are sufficiently well represented in the training dataset, and the other condition is that the target sample contains cell subsets that are common among different tissues. When either of these conditions is met, the clock performs well. It is also suggested that the epigenetic age of all samples in the target tissue tends to be either over or underestimated when biological age prediction fails. The model can reveal the statistical characteristics of DNA methylation clocks.
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Affiliation(s)
- Daigo Okada
- Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, 53 Syogoin-Kawaramachi, Sakyo-ku, Kyoto, Kyoto, 606-8507, Japan.
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3
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Le Clercq LS, Kotzé A, Grobler JP, Dalton DL. Biological clocks as age estimation markers in animals: a systematic review and meta-analysis. Biol Rev Camb Philos Soc 2023; 98:1972-2011. [PMID: 37356823 DOI: 10.1111/brv.12992] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 06/04/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Various biological attributes associated with individual fitness in animals change predictably over the lifespan of an organism. Therefore, the study of animal ecology and the work of conservationists frequently relies upon the ability to assign animals to functionally relevant age classes to model population fitness. Several approaches have been applied to determining individual age and, while these methods have proved useful, they are not without limitations and often lack standardisation or are only applicable to specific species. For these reasons, scientists have explored the potential use of biological clocks towards creating a universal age-determination method. Two biological clocks, tooth layer annulation and otolith layering have found universal appeal. Both methods are highly invasive and most appropriate for post-mortem age-at-death estimation. More recently, attributes of cellular ageing previously explored in humans have been adapted to studying ageing in animals for the use of less-invasive molecular methods for determining age. Here, we review two such methods, assessment of methylation and telomere length, describing (i) what they are, (ii) how they change with age, and providing (iii) a summary and meta-analysis of studies that have explored their utility in animal age determination. We found that both attributes have been studied across multiple vertebrate classes, however, telomere studies were used before methylation studies and telomere length has been modelled in nearly twice as many studies. Telomere length studies included in the review often related changes to stress responses and illustrated that telomere length is sensitive to environmental and social stressors and, in the absence of repair mechanisms such as telomerase or alternative lengthening modes, lacks the ability to recover. Methylation studies, however, while also detecting sensitivity to stressors and toxins, illustrated the ability to recover from such stresses after a period of accelerated ageing, likely due to constitutive expression or reactivation of repair enzymes such as DNA methyl transferases. We also found that both studied attributes have parentally heritable features, but the mode of inheritance differs among taxa and may relate to heterogamy. Our meta-analysis included more than 40 species in common for methylation and telomere length, although both analyses included at least 60 age-estimation models. We found that methylation outperforms telomere length in terms of predictive power evidenced from effect sizes (more than double that observed for telomeres) and smaller prediction intervals. Both methods produced age correlation models using similar sample sizes and were able to classify individuals into young, middle, or old age classes with high accuracy. Our review and meta-analysis illustrate that both methods are well suited to studying age in animals and do not suffer significantly from variation due to differences in the lifespan of the species, genome size, karyotype, or tissue type but rather that quantitative method, patterns of inheritance, and environmental factors should be the main considerations. Thus, provided that complex factors affecting the measured trait can be accounted for, both methylation and telomere length are promising targets to develop as biomarkers for age determination in animals.
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Affiliation(s)
- Louis-Stéphane Le Clercq
- South African National Biodiversity Institute, P.O. Box 754, Pretoria, 0001, South Africa
- Department of Genetics, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Antoinette Kotzé
- South African National Biodiversity Institute, P.O. Box 754, Pretoria, 0001, South Africa
- Department of Genetics, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - J Paul Grobler
- Department of Genetics, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Desiré Lee Dalton
- School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BA, UK
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4
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Lu YR, Tian X, Sinclair DA. The Information Theory of Aging. NATURE AGING 2023; 3:1486-1499. [PMID: 38102202 DOI: 10.1038/s43587-023-00527-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 10/02/2023] [Indexed: 12/17/2023]
Abstract
Information storage and retrieval is essential for all life. In biology, information is primarily stored in two distinct ways: the genome, comprising nucleic acids, acts as a foundational blueprint and the epigenome, consisting of chemical modifications to DNA and histone proteins, regulates gene expression patterns and endows cells with specific identities and functions. Unlike the stable, digital nature of genetic information, epigenetic information is stored in a digital-analog format, susceptible to alterations induced by diverse environmental signals and cellular damage. The Information Theory of Aging (ITOA) states that the aging process is driven by the progressive loss of youthful epigenetic information, the retrieval of which via epigenetic reprogramming can improve the function of damaged and aged tissues by catalyzing age reversal.
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Affiliation(s)
- Yuancheng Ryan Lu
- Paul F. Glenn Center for Biology of Aging Research, Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xiao Tian
- Paul F. Glenn Center for Biology of Aging Research, Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - David A Sinclair
- Paul F. Glenn Center for Biology of Aging Research, Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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5
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Tangili M, Slettenhaar AJ, Sudyka J, Dugdale HL, Pen I, Palsbøll PJ, Verhulst S. DNA methylation markers of age(ing) in non-model animals. Mol Ecol 2023; 32:4725-4741. [PMID: 37401200 DOI: 10.1111/mec.17065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/05/2023]
Abstract
Inferring the chronological and biological age of individuals is fundamental to population ecology and our understanding of ageing itself, its evolution, and the biological processes that affect or even cause ageing. Epigenetic clocks based on DNA methylation (DNAm) at specific CpG sites show a strong correlation with chronological age in humans, and discrepancies between inferred and actual chronological age predict morbidity and mortality. Recently, a growing number of epigenetic clocks have been developed in non-model animals and we here review these studies. We also conduct a meta-analysis to assess the effects of different aspects of experimental protocol on the performance of epigenetic clocks for non-model animals. Two measures of performance are usually reported, the R2 of the association between the predicted and chronological age, and the mean/median absolute deviation (MAD) of estimated age from chronological age, and we argue that only the MAD reflects accuracy. R2 for epigenetic clocks based on the HorvathMammalMethylChip4 was higher and the MAD scaled to age range lower, compared with other DNAm quantification approaches. Scaled MAD tended to be lower among individuals in captive populations, and decreased with an increasing number of CpG sites. We conclude that epigenetic clocks can predict chronological age with relatively high accuracy, suggesting great potential in ecological epigenetics. We discuss general aspects of epigenetic clocks in the hope of stimulating further DNAm-based research on ageing, and perhaps more importantly, other key traits.
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Affiliation(s)
- Marianthi Tangili
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Annabel J Slettenhaar
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Joanna Sudyka
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Hannah L Dugdale
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
- Faculty of Biological Sciences, School of Biology, University of Leeds, Leeds, UK
| | - Ido Pen
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Per J Palsbøll
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
- Center for Coastal Studies, Provincetown, Massachusetts, USA
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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6
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Li A, Koch Z, Ideker T. Epigenetic aging: Biological age prediction and informing a mechanistic theory of aging. J Intern Med 2022; 292:733-744. [PMID: 35726002 DOI: 10.1111/joim.13533] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Numerous studies have shown that epigenetic age-an individual's degree of aging based on patterns of DNA methylation-can be computed and is associated with an array of factors including diet, lifestyle, genetics, and disease. One can expect that still further associations will emerge with additional aging research, but to what end? Prediction of age was an important first step, but-in our view-the focus must shift from chasing increasingly accurate age computations to understanding the links between the epigenome and the mechanisms and physiological changes of aging. Here, we outline emerging areas of epigenetic aging research that prioritize biological understanding and clinical application. First, we survey recent progress in epigenetic clocks, which are beginning to predict not only chronological age but aging outcomes such as all-cause mortality and onset of disease, or which integrate aging signals across multiple biological processes. Second, we discuss research that exemplifies how investigation of the epigenome is building a mechanistic theory of aging and informing clinical practice. Such examples include identifying methylation sites and the genes most strongly predictive of aging-a subset of which have shown strong potential as biomarkers of neurodegenerative disease and cancer; relating epigenetic clock predictions to hallmarks of aging; and using longitudinal studies of DNA methylation to characterize human disease, resulting in the discovery of epigenetic indications of type 1 diabetes and the propensity for psychotic experiences.
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Affiliation(s)
- Adam Li
- Division of Genetics, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Zane Koch
- Division of Genetics, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Trey Ideker
- Division of Genetics, Department of Medicine, University of California San Diego, La Jolla, California, USA
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7
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Savina A, Jaffredo T, Saldmann F, Faulkes CG, Moguelet P, Leroy C, Marmol DD, Codogno P, Foucher L, Zalc A, Viltard M, Friedlander G, Aractingi S, Fontaine RH. Single-cell transcriptomics reveals age-resistant maintenance of cell identities, stem cell compartments and differentiation trajectories in long-lived naked mole-rats skin. Aging (Albany NY) 2022; 14:3728-3756. [PMID: 35507806 PMCID: PMC9134947 DOI: 10.18632/aging.204054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/25/2022] [Indexed: 11/25/2022]
Abstract
Naked mole-rats (NMR) are subterranean rodents characterized by an unusual longevity coupled with an unexplained resistance to aging. In the present study, we performed extensive in situ analysis and single-cell RNA-sequencing comparing young and older animals. At variance with other species, NMR exhibited a striking stability of skin compartments and cell types, which remained stable over time without aging-associated changes. Remarkably, the number of stem cells was constant throughout aging. We found three classical cellular states defining a unique keratinocyte differentiation trajectory that were not altered after pseudo-temporal reconstruction. Epidermal gene expression did not change with aging either. Langerhans cell clusters were conserved, and only a higher basal stem cell expression of Igfbp3 was found in aged animals. In accordance, NMR skin healing closure was similar in young and older animals. Altogether, these results indicate that NMR skin is characterized by peculiar genetic and cellular features, different from those previously demonstrated for mice and humans. The remarkable stability of the aging NMR skin transcriptome likely reflects unaltered homeostasis and resilience.
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Affiliation(s)
| | - Thierry Jaffredo
- Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Sorbonne Université, CNRS, INSERM, Paris, France
| | | | - Chris G Faulkes
- Queen Mary University of London, School of Biological and Chemical Sciences, London, United Kingdom
| | - Philippe Moguelet
- Service d'Anatomie et Cytologie Pathologiques, Hôpital Tenon, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Christine Leroy
- Université Paris Cité, CNRS, INSERM, Institut Necker-Enfants Malades, Paris, France
| | | | - Patrice Codogno
- Université Paris Cité, CNRS, INSERM, Institut Necker-Enfants Malades, Paris, France
| | - Lucy Foucher
- Ecole Nationale Vétérinaire d'Alfort, Centre de Recherche Biomédicale, Maisons-Alfort, France
| | - Antoine Zalc
- Université Paris Cité, CNRS, INSERM, Institut Cochin, Paris, France
| | - Mélanie Viltard
- Fondation pour la Recherche en Physiologie, Brussels, Belgium
| | - Gérard Friedlander
- Université Paris Cité, CNRS, INSERM, Institut Necker-Enfants Malades, Paris, France
| | - Selim Aractingi
- Université Paris Cité, CNRS, INSERM, Institut Cochin, Paris, France.,Service de Dermatologie, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris, France
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8
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Epigenetic aging of the demographically non-aging naked mole-rat. Nat Commun 2022; 13:355. [PMID: 35039495 PMCID: PMC8763950 DOI: 10.1038/s41467-022-27959-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 12/23/2021] [Indexed: 12/26/2022] Open
Abstract
The naked mole-rat (NMR) is an exceptionally long-lived rodent that shows no increase of mortality with age, defining it as a demographically non-aging mammal. Here, we perform bisulfite sequencing of the blood of > 100 NMRs, assessing > 3 million common CpG sites. Unsupervised clustering based on sites whose methylation correlates with age reveals an age-related methylome remodeling, and we also observe a methylome information loss, suggesting that NMRs age. We develop an epigenetic aging clock that accurately predicts the NMR age. We show that these animals age much slower than mice and much faster than humans, consistent with their known maximum lifespans. Interestingly, patterns of age-related changes of clock sites in Tert and Prpf19 differ between NMRs and mice, but there are also sites conserved between the two species. Together, the data indicate that NMRs, like other mammals, epigenetically age even in the absence of demographic aging of this species. The exceptionally long-lived naked mole-rat is characterized by the lack of increased mortality with aging. Here the authors perform epigenetic studies to show that naked mole-rats epigenetically age despite their non-increasing mortality rate.
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9
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Boison D, Masino SA, Lubin FD, Guo K, Lusardi T, Sanchez R, Ruskin DN, Ohm J, Geiger JD, Hur J. The impact of methodology on the reproducibility and rigor of DNA methylation data. Sci Rep 2022; 12:380. [PMID: 35013473 PMCID: PMC8748700 DOI: 10.1038/s41598-021-04346-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 12/14/2021] [Indexed: 01/05/2023] Open
Abstract
Epigenetic modifications are crucial for normal development and implicated in disease pathogenesis. While epigenetics continues to be a burgeoning research area in neuroscience, unaddressed issues related to data reproducibility across laboratories remain. Separating meaningful experimental changes from background variability is a challenge in epigenomic studies. Here we show that seemingly minor experimental variations, even under normal baseline conditions, can have a significant impact on epigenome outcome measures and data interpretation. We examined genome-wide DNA methylation and gene expression profiles of hippocampal tissues from wild-type rats housed in three independent laboratories using nearly identical conditions. Reduced-representation bisulfite sequencing and RNA-seq respectively identified 3852 differentially methylated and 1075 differentially expressed genes between laboratories, even in the absence of experimental intervention. Difficult-to-match factors such as animal vendors and a subset of husbandry and tissue extraction procedures produced quantifiable variations between wild-type animals across the three laboratories. Our study demonstrates that seemingly minor experimental variations, even under normal baseline conditions, can have a significant impact on epigenome outcome measures and data interpretation. This is particularly meaningful for neurological studies in animal models, in which baseline parameters between experimental groups are difficult to control. To enhance scientific rigor, we conclude that strict adherence to protocols is necessary for the execution and interpretation of epigenetic studies and that protocol-sensitive epigenetic changes, amongst naive animals, may confound experimental results.
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Affiliation(s)
- Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA
| | - Susan A Masino
- Department of Psychology and Neuroscience Program, Trinity College, Hartford, CT, 06106, USA
| | - Farah D Lubin
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Kai Guo
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Theresa Lusardi
- Knight Cancer Institute, Cancer Early Detection Advanced Research Center, Oregon Health and Science University, Portland, OR, 97239, USA
- Dow Neurobiology Labs, Legacy Research Institute, Portland, OR, 97232, USA
| | - Richard Sanchez
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
- Division of Biological Sciences, Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA
| | - David N Ruskin
- Department of Psychology and Neuroscience Program, Trinity College, Hartford, CT, 06106, USA
| | - Joyce Ohm
- Department of Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, 14263, USA
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA.
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10
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Horvath S, Haghani A, Macoretta N, Ablaeva J, Zoller JA, Li CZ, Zhang J, Takasugi M, Zhao Y, Rydkina E, Zhang Z, Emmrich S, Raj K, Seluanov A, Faulkes CG, Gorbunova V. DNA methylation clocks tick in naked mole rats but queens age more slowly than nonbreeders. NATURE AGING 2022; 2:46-59. [PMID: 35368774 PMCID: PMC8975251 DOI: 10.1038/s43587-021-00152-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
Naked mole rats (NMRs) live an exceptionally long life, appear not to exhibit age-related decline in physiological capacity and are resistant to age-related diseases. However, it has been unknown whether NMRs also evade aging according to a primary hallmark of aging: epigenetic changes. To address this question, we profiled n = 385 samples from 11 tissue types at loci that are highly conserved between mammalian species using a custom array (HorvathMammalMethylChip40). We observed strong epigenetic aging effects and developed seven highly accurate epigenetic clocks for several tissues (pan-tissue, blood, kidney, liver, skin clocks) and two dual-species (human-NMR) clocks. The skin clock correctly estimated induced pluripotent stem cells derived from NMR fibroblasts to be of prenatal age. The NMR epigenetic clocks revealed that breeding NMR queens age more slowly than nonbreeders, a feature that is also observed in some eusocial insects. Our results show that despite a phenotype of negligible senescence, the NMR ages epigenetically.
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Affiliation(s)
- Steve Horvath
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, USA
- Altos Labs, San Diego, CA, USA
- These authors contributed equally: Steve Horvath, Amin Haghani
| | - Amin Haghani
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- These authors contributed equally: Steve Horvath, Amin Haghani
| | - Nicholas Macoretta
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Julia Ablaeva
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Joseph A. Zoller
- Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, USA
| | - Caesar Z. Li
- Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, USA
| | - Joshua Zhang
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Masaki Takasugi
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Yang Zhao
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Elena Rydkina
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Zhihui Zhang
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Stephan Emmrich
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
| | - Ken Raj
- Radiation Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, UK
| | - Andrei Seluanov
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
- These authors jointly supervised this work: Andrei Seluanov, Chris G. Faulkes, Vera Gorbunova
| | - Chris G. Faulkes
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
- These authors jointly supervised this work: Andrei Seluanov, Chris G. Faulkes, Vera Gorbunova
| | - Vera Gorbunova
- Departments of Biology and Medicine, University of Rochester, Rochester, NY, USA
- These authors jointly supervised this work: Andrei Seluanov, Chris G. Faulkes, Vera Gorbunova
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11
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Heydenrych MJ, Saunders BJ, Bunce M, Jarman SN. Epigenetic Measurement of Key Vertebrate Population Biology Parameters. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.617376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The age, sex, and sexual maturity of individual animals are key parameters in assessing wild populations and informing conservation management strategies. These parameters represent the reproductive potential of a population and can indicate recovery rates or vulnerabilities. Natural populations of wild animals are difficult to study; logistically, economically, and due to the impacts of invasive biomonitoring. Genetic and epigenetic analyses offer a low impact, low cost, and information-rich alternative. As epigenetic mechanisms are intrinsically linked with both biological aging and reproductive processes, DNA methylation can be used as a suitable biomarker for population biology study. This review assesses published research utilizing DNA methylation analysis in relation to three key population parameters: age, sex, and sexual maturity. We review studies on wild vertebrates that investigate epigenetic age relationships, with successful age estimation assays designed for mammals, birds, and fish. For both determination of sex and identification of sexual maturity, very little has been explored regarding DNA methylation-based assays. Related research, however, confirms the links between DNA methylation and these processes. Future development of age estimation assays for underrepresented and key conservation taxa is suggested, as is the experimental development and design of DNA methylation-based assays for both sex and sexual maturity identification, further expanding the genomics toolkit for population biology studies.
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12
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Bertucci EM, Mason MW, Rhodes OE, Parrott BB. Exposure to ionizing radiation disrupts normal epigenetic aging in Japanese medaka. Aging (Albany NY) 2021; 13:22752-22771. [PMID: 34644261 PMCID: PMC8544305 DOI: 10.18632/aging.203624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/03/2021] [Indexed: 02/06/2023]
Abstract
Alterations to the epigenome are a hallmark of biological aging and age-dependent patterning of the DNA methylome ("epigenetic aging") can be modeled to produce epigenetic age predictors. Rates of epigenetic aging vary amongst individuals and correlate to the onset of age-related disease and all-cause mortality. Yet, the origins of epigenetic-to-chronological age discordance are not empirically resolved. Here, we investigate the relationship between aging, DNA methylation, and environmental exposures in Japanese medaka (Oryzias latipes). We find age-associated DNA methylation patterning enriched in genomic regions of low CpG density and that, similar to mammals, most age-related changes occur during early life. We construct an epigenetic clock capable of predicting chronological age with a mean error of 61.1 days (~8.4% of average lifespan). To test the role of environmental factors in driving epigenetic age variation, we exposed medaka to chronic, environmentally relevant doses of ionizing radiation. Because most organisms share an evolutionary history with ionizing radiation, we hypothesized that exposure would reveal fundamental insights into environment-by-epigenetic aging interactions. Radiation exposure disrupted epigenetic aging by accelerating and decelerating normal age-associated patterning and was most pronounced in cytosines that were moderately associated with age. These findings empirically demonstrate the role of DNA methylation in integrating environmental factors into aging trajectories.
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Affiliation(s)
- Emily M. Bertucci
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
| | - Marilyn W. Mason
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
| | - Olin E. Rhodes
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
| | - Benjamin B. Parrott
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802, USA
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13
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Simpson DJ, Chandra T. Epigenetic age prediction. Aging Cell 2021; 20:e13452. [PMID: 34415665 PMCID: PMC8441394 DOI: 10.1111/acel.13452] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 12/14/2022] Open
Abstract
Advanced age is the main common risk factor for cancer, cardiovascular disease and neurodegeneration. Yet, more is known about the molecular basis of any of these groups of diseases than the changes that accompany ageing itself. Progress in molecular ageing research was slow because the tools predicting whether someone aged slowly or fast (biological age) were unreliable. To understand ageing as a risk factor for disease and to develop interventions, the molecular ageing field needed a quantitative measure; a clock for biological age. Over the past decade, a number of age predictors utilising DNA methylation have been developed, referred to as epigenetic clocks. While they appear to estimate biological age, it remains unclear whether the methylation changes used to train the clocks are a reflection of other underlying cellular or molecular processes, or whether methylation itself is involved in the ageing process. The precise aspects of ageing that the epigenetic clocks capture remain hidden and seem to vary between predictors. Nonetheless, the use of epigenetic clocks has opened the door towards studying biological ageing quantitatively, and new clocks and applications, such as forensics, appear frequently. In this review, we will discuss the range of epigenetic clocks available, their strengths and weaknesses, and their applicability to various scientific queries.
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Affiliation(s)
- Daniel J. Simpson
- MRC Human Genetics UnitMRC Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
| | - Tamir Chandra
- MRC Human Genetics UnitMRC Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghUK
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14
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Torrillas de la Cal A, Paniagua-Torija B, Arevalo-Martin A, Faulkes CG, Jiménez AJ, Ferrer I, Molina-Holgado E, Garcia-Ovejero D. The Structure of the Spinal Cord Ependymal Region in Adult Humans Is a Distinctive Trait among Mammals. Cells 2021; 10:2235. [PMID: 34571884 PMCID: PMC8469235 DOI: 10.3390/cells10092235] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 02/06/2023] Open
Abstract
In species that regenerate the injured spinal cord, the ependymal region is a source of new cells and a prominent coordinator of regeneration. In mammals, cells at the ependymal region proliferate in normal conditions and react after injury, but in humans, the central canal is lost in the majority of individuals from early childhood. It is replaced by a structure that does not proliferate after damage and is formed by large accumulations of ependymal cells, strong astrogliosis and perivascular pseudo-rosettes. We inform here of two additional mammals that lose the central canal during their lifetime: the Naked Mole-Rat (NMR, Heterocephalus glaber) and the mutant hyh (hydrocephalus with hop gait) mice. The morphological study of their spinal cords shows that the tissue substituting the central canal is not similar to that found in humans. In both NMR and hyh mice, the central canal is replaced by tissue reminiscent of normal lamina X and may include small groups of ependymal cells in the midline, partially resembling specific domains of the former canal. However, no features of the adult human ependymal remnant are found, suggesting that this structure is a specific human trait. In order to shed some more light on the mechanism of human central canal closure, we provide new data suggesting that canal patency is lost by delamination of the ependymal epithelium, in a process that includes apical polarity loss and the expression of signaling mediators involved in epithelial to mesenchymal transitions.
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Affiliation(s)
- Alejandro Torrillas de la Cal
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos, 45071 Toledo, Spain; (A.T.d.l.C.); (B.P.-T.); (A.A.-M.); (E.M.-H.)
| | - Beatriz Paniagua-Torija
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos, 45071 Toledo, Spain; (A.T.d.l.C.); (B.P.-T.); (A.A.-M.); (E.M.-H.)
| | - Angel Arevalo-Martin
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos, 45071 Toledo, Spain; (A.T.d.l.C.); (B.P.-T.); (A.A.-M.); (E.M.-H.)
| | - Christopher Guy Faulkes
- School of Biological & Chemical Sciences, Queen Mary University of London, London E1 4NS, UK;
| | - Antonio Jesús Jiménez
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus de Teatinos, 29071 Malaga, Spain;
- Instituto de Investigación Biomédica de Málaga (IBIMA), 29010 Malaga, Spain
| | - Isidre Ferrer
- Institut de Neuropatologia, Servei d’Anatomia Patològica, IDIBELL-Hospital Universitari de Bellvitge, Universitat de Barcelona, 08908 L’Hospitalet de Llobregat, Spain;
| | - Eduardo Molina-Holgado
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos, 45071 Toledo, Spain; (A.T.d.l.C.); (B.P.-T.); (A.A.-M.); (E.M.-H.)
| | - Daniel Garcia-Ovejero
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos, 45071 Toledo, Spain; (A.T.d.l.C.); (B.P.-T.); (A.A.-M.); (E.M.-H.)
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Narayan V, McMahon M, O'Brien JJ, McAllister F, Buffenstein R. Insights into the Molecular Basis of Genome Stability and Pristine Proteostasis in Naked Mole-Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:287-314. [PMID: 34424521 DOI: 10.1007/978-3-030-65943-1_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The naked mole-rat (Heterocephalus glaber) is the longest-lived rodent, with a maximal reported lifespan of 37 years. In addition to its long lifespan - which is much greater than predicted based on its small body size (longevity quotient of ~4.2) - naked mole-rats are also remarkably healthy well into old age. This is reflected in a striking resistance to tumorigenesis and minimal declines in cardiovascular, neurological and reproductive function in older animals. Over the past two decades, researchers have been investigating the molecular mechanisms regulating the extended life- and health- span of this animal, and since the sequencing and assembly of the naked mole-rat genome in 2011, progress has been rapid. Here, we summarize findings from published studies exploring the unique molecular biology of the naked mole-rat, with a focus on mechanisms and pathways contributing to genome stability and maintenance of proteostasis during aging. We also present new data from our laboratory relevant to the topic and discuss our findings in the context of the published literature.
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Affiliation(s)
| | - Mary McMahon
- Calico Life Sciences, LLC, South San Francisco, CA, USA
| | | | | | - Rochelle Buffenstein
- Calico Life Sciences, LLC, South San Francisco, CA, USA. .,Department of Pharmacology, University of Texas Health at San Antonio, San Antonio, TX, USA.
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