1
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Ndhlovu LC, Bendall ML, Dwaraka V, Pang APS, Dopkins N, Carreras N, Smith R, Nixon DF, Corley MJ. Retro-age: A unique epigenetic biomarker of aging captured by DNA methylation states of retroelements. Aging Cell 2024:e14288. [PMID: 39092674 DOI: 10.1111/acel.14288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 07/11/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024] Open
Abstract
Reactivation of retroelements in the human genome has been linked to aging. However, whether the epigenetic state of specific retroelements can predict chronological age remains unknown. We provide evidence that locus-specific retroelement DNA methylation can be used to create retroelement-based epigenetic clocks that accurately measure chronological age in the immune system, across human tissues, and pan-mammalian species. We also developed a highly accurate retroelement epigenetic clock compatible with EPICv.2.0 data that was constructed from CpGs that did not overlap with existing first- and second-generation epigenetic clocks, suggesting a unique signal for epigenetic clocks not previously captured. We found retroelement-based epigenetic clocks were reversed during transient epigenetic reprogramming, accelerated in people living with HIV-1, and responsive to antiretroviral therapy. Our findings highlight the utility of retroelement-based biomarkers of aging and support a renewed emphasis on the role of retroelements in geroscience.
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Affiliation(s)
- Lishomwa C Ndhlovu
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, New York City, USA
| | - Matthew L Bendall
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, New York City, USA
| | | | - Alina P S Pang
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, New York City, USA
| | - Nicholas Dopkins
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, New York City, USA
| | | | | | - Douglas F Nixon
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, New York City, USA
| | - Michael J Corley
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, New York City, USA
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2
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Frost B, Dubnau J. The Role of Retrotransposons and Endogenous Retroviruses in Age-Dependent Neurodegenerative Disorders. Annu Rev Neurosci 2024; 47:123-143. [PMID: 38663088 DOI: 10.1146/annurev-neuro-082823-020615] [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] [Indexed: 08/09/2024]
Abstract
Over 40% of the human genome is composed of retrotransposons, DNA species that hold the potential to replicate via an RNA intermediate and are evolutionarily related to retroviruses. Retrotransposons are most studied for their ability to jump within a genome, which can cause DNA damage and novel insertional mutations. Retrotransposon-encoded products, including viral-like proteins, double-stranded RNAs, and extrachromosomal circular DNAs, can also be potent activators of the innate immune system. A growing body of evidence suggests that retrotransposons are activated in age-related neurodegenerative disorders and that such activation causally contributes to neurotoxicity. Here we provide an overview of retrotransposon biology and outline evidence of retrotransposon activation in age-related neurodegenerative disorders, with an emphasis on those involving TAR-DNA binding protein-43 (TDP-43) and tau. Studies to date provide the basis for ongoing clinical trials and hold promise for innovative strategies to ameliorate the adverse effects of retrotransposon dysregulation in neurodegenerative disorders.
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Affiliation(s)
- Bess Frost
- Sam and Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, and Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas, USA;
| | - Josh Dubnau
- Department of Anesthesiology and Department of Neurobiology and Behavior, Stony Brook School of Medicine, Stony Brook, New York, USA;
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3
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Talley MJ, Longworth MS. Retrotransposons in embryogenesis and neurodevelopment. Biochem Soc Trans 2024; 52:1159-1171. [PMID: 38716891 DOI: 10.1042/bst20230757] [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: 02/07/2024] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 06/27/2024]
Abstract
Retrotransposable elements (RTEs) are genetic elements that can replicate and insert new copies into different genomic locations. RTEs have long been identified as 'parasitic genes', as their mobilization can cause mutations, DNA damage, and inflammation. Interestingly, high levels of retrotransposon activation are observed in early embryogenesis and neurodevelopment, suggesting that RTEs may possess functional roles during these stages of development. Recent studies demonstrate that RTEs can function as transcriptional regulatory elements through mechanisms such as chromatin organization and noncoding RNAs. It is clear, however, that RTE expression and activity must be restrained at some level during development, since overactivation of RTEs during neurodevelopment is associated with several developmental disorders. Further investigation is needed to understand the importance of RTE expression and activity during neurodevelopment and the balance between RTE-regulated development and RTE-mediated pathogenesis.
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Affiliation(s)
- Mary Jo Talley
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, U.S.A
| | - Michelle S Longworth
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, U.S.A
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44195, U.S.A
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4
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Stanković D, Tain LS, Uhlirova M. Xrp1 governs the stress response program to spliceosome dysfunction. Nucleic Acids Res 2024; 52:2093-2111. [PMID: 38303573 PMCID: PMC10954486 DOI: 10.1093/nar/gkae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 01/03/2024] [Accepted: 01/16/2024] [Indexed: 02/03/2024] Open
Abstract
Co-transcriptional processing of nascent pre-mRNAs by the spliceosome is vital to regulating gene expression and maintaining genome integrity. Here, we show that the deficiency of functional U5 small nuclear ribonucleoprotein particles (snRNPs) in Drosophila imaginal cells causes extensive transcriptome remodeling and accumulation of highly mutagenic R-loops, triggering a robust stress response and cell cycle arrest. Despite compromised proliferative capacity, the U5 snRNP-deficient cells increased protein translation and cell size, causing intra-organ growth disbalance before being gradually eliminated via apoptosis. We identify the Xrp1-Irbp18 heterodimer as the primary driver of transcriptional and cellular stress program downstream of U5 snRNP malfunction. Knockdown of Xrp1 or Irbp18 in U5 snRNP-deficient cells attenuated JNK and p53 activity, restored normal cell cycle progression and growth, and inhibited cell death. Reducing Xrp1-Irbp18, however, did not rescue the splicing defects, highlighting the requirement of accurate splicing for cellular and tissue homeostasis. Our work provides novel insights into the crosstalk between splicing and the DNA damage response and defines the Xrp1-Irbp18 heterodimer as a critical sensor of spliceosome malfunction and mediator of the stress-induced cellular senescence program.
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Affiliation(s)
- Dimitrije Stanković
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Luke S Tain
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Mirka Uhlirova
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
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5
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Ndhlovu LC, Bendall ML, Dwaraka V, Pang APS, Dopkins N, Carreras N, Smith R, Nixon DF, Corley MJ. Retroelement-Age Clocks: Epigenetic Age Captured by Human Endogenous Retrovirus and LINE-1 DNA methylation states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570422. [PMID: 38106164 PMCID: PMC10723416 DOI: 10.1101/2023.12.06.570422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Human endogenous retroviruses (HERVs), the remnants of ancient viral infections embedded within the human genome, and long interspersed nuclear elements 1 (LINE-1), a class of autonomous retrotransposons, are silenced by host epigenetic mechanisms including DNA methylation. The resurrection of particular retroelements has been linked to biological aging. Whether the DNA methylation states of locus specific HERVs and LINEs can be used as a biomarker of chronological age in humans remains unclear. We show that highly predictive epigenetic clocks of chronological age can be constructed from retroelement DNA methylation states in the immune system, across human tissues, and pan-mammalian species. We found retroelement epigenetic clocks were reversed during transient epigenetic reprogramming, accelerated in people living with HIV-1, responsive to antiretroviral therapy, and accurate in estimating long-term culture ages of human brain organoids. Our findings support the hypothesis of epigenetic dysregulation of retroelements as a potential contributor to the biological hallmarks of aging.
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Affiliation(s)
- Lishomwa C. Ndhlovu
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York City, New York, USA
| | - Matthew L. Bendall
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York City, New York, USA
| | | | - Alina PS Pang
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York City, New York, USA
| | - Nicholas Dopkins
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York City, New York, USA
| | | | | | - Douglas F. Nixon
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York City, New York, USA
| | - Michael J. Corley
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York City, New York, USA
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6
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Xu A, Teefy BB, Lu RJ, Nozownik S, Tyers AM, Valenzano DR, Benayoun BA. Transcriptomes of aging brain, heart, muscle, and spleen from female and male African turquoise killifish. Sci Data 2023; 10:695. [PMID: 37828039 PMCID: PMC10570339 DOI: 10.1038/s41597-023-02609-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
The African turquoise killifish is an emerging vertebrate model organism with great potential for aging research due to its naturally short lifespan. Thus far, turquoise killifish aging 'omic' studies have examined a single organ, single sex and/or evaluated samples from non-reference strains. Here, we describe a resource dataset of ribosomal RNA-depleted RNA-seq libraries generated from the brain, heart, muscle, and spleen from both sexes, as well as young and old animals, in the reference GRZ turquoise killifish strain. We provide basic quality control steps and demonstrate the utility of our dataset by performing differential gene expression and gene ontology analyses by age and sex. Importantly, we show that age has a greater impact than sex on transcriptional landscapes across probed tissues. Finally, we confirm transcription of transposable elements (TEs), which are highly abundant and increase in expression with age in brain tissue. This dataset will be a useful resource for exploring gene and TE expression as a function of both age and sex in a powerful naturally short-lived vertebrate model.
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Affiliation(s)
- Alan Xu
- Quantitative & Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, CA, 90089, USA
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Bryan B Teefy
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Ryan J Lu
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
- Graduate Program in the Biology of Aging, University of Southern California, Los Angeles, CA, USA
| | - Séverine Nozownik
- Unit of Forensic Genetics, University Center of Legal Medicine, Lausanne, Switzerland
| | - Alexandra M Tyers
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann Strasse 9b, 50931, Cologne, Germany
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Vairão, Portugal
| | - Dario R Valenzano
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann Strasse 9b, 50931, Cologne, Germany
| | - Bérénice A Benayoun
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA.
- Molecular and Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, CA, 90089, USA.
- Biochemistry and Molecular Medicine Department, USC Keck School of Medicine, Los Angeles, CA, 90089, USA.
- USC Norris Comprehensive Cancer Center, Epigenetics and Gene Regulation, Los Angeles, CA, 90089, USA.
- USC Stem Cell Initiative, Los Angeles, CA, 90089, USA.
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7
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Merkling SH, Crist AB, Henrion-Lacritick A, Frangeul L, Couderc E, Gausson V, Blanc H, Bergman A, Baidaliuk A, Romoli O, Saleh MC, Lambrechts L. Multifaceted contributions of Dicer2 to arbovirus transmission by Aedes aegypti. Cell Rep 2023; 42:112977. [PMID: 37573505 DOI: 10.1016/j.celrep.2023.112977] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 06/20/2023] [Accepted: 07/28/2023] [Indexed: 08/15/2023] Open
Abstract
Arthropod-borne viruses (arboviruses) transmitted by Aedes aegypti mosquitoes are an increasing threat to global health. The small interfering RNA (siRNA) pathway is considered the main antiviral immune pathway of insects, but its effective impact on arbovirus transmission is surprisingly poorly understood. Here, we use CRISPR-Cas9-mediated gene editing in vivo to mutate Dicer2, a gene encoding the RNA sensor and key component of the siRNA pathway. The loss of Dicer2 enhances early viral replication and systemic viral dissemination of four medically significant arboviruses (chikungunya, Mayaro, dengue, and Zika viruses) representing two viral families. However, Dicer2 mutants and wild-type mosquitoes display overall similar levels of vector competence. In addition, Dicer2 mutants undergo significant virus-induced mortality during infection with chikungunya virus. Together, our results define a multifaceted role for Dicer2 in the transmission of arboviruses by Ae. aegypti mosquitoes and pave the way for further mechanistic investigations.
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Affiliation(s)
- Sarah Hélène Merkling
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, 75015 Paris, France
| | - Anna Beth Crist
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, 75015 Paris, France
| | - Annabelle Henrion-Lacritick
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, 75015 Paris, France
| | - Lionel Frangeul
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, 75015 Paris, France
| | - Elodie Couderc
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, 75015 Paris, France; Sorbonne Université, Collège Doctoral, 75005 Paris, France
| | - Valérie Gausson
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, 75015 Paris, France
| | - Hervé Blanc
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, 75015 Paris, France
| | - Alexander Bergman
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, 75015 Paris, France
| | - Artem Baidaliuk
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, 75015 Paris, France; Sorbonne Université, Collège Doctoral, 75005 Paris, France
| | - Ottavia Romoli
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, 75015 Paris, France
| | - Maria-Carla Saleh
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, 75015 Paris, France.
| | - Louis Lambrechts
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, 75015 Paris, France.
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8
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Wodrich APK, Scott AW, Giniger E. What do we mean by "aging"? Questions and perspectives revealed by studies in Drosophila. Mech Ageing Dev 2023; 213:111839. [PMID: 37354919 PMCID: PMC10330756 DOI: 10.1016/j.mad.2023.111839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 06/26/2023]
Abstract
What is the nature of aging, and how best can we study it? Here, using a series of questions that highlight differing perspectives about the nature of aging, we ask how data from Drosophila melanogaster at the organismal, tissue, cellular, and molecular levels shed light on the complex interactions among the phenotypes associated with aging. Should aging be viewed as an individual's increasing probability of mortality over time or as a progression of physiological states? Are all age-correlated changes in physiology detrimental to vigor or are some compensatory changes that maintain vigor? Why do different age-correlated functions seem to change at different rates in a single individual as it ages? Should aging be considered as a single, integrated process across the scales of biological resolution, from organismal to molecular, or must we consider each level of biological scale as a separate, distinct entity? Viewing aging from these differing perspectives yields distinct but complementary interpretations about the properties and mechanisms of aging and may offer a path through the complexities related to understanding the nature of aging.
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Affiliation(s)
- Andrew P K Wodrich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, United States; Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, United States; College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Andrew W Scott
- National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, United States.
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9
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Schneider BK, Sun S, Lee M, Li W, Skvir N, Neretti N, Vijg J, Secombe J. Expression of retrotransposons contributes to aging in Drosophila. Genetics 2023; 224:iyad073. [PMID: 37084379 PMCID: PMC10213499 DOI: 10.1093/genetics/iyad073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/12/2022] [Accepted: 04/11/2023] [Indexed: 04/23/2023] Open
Abstract
Retrotransposons are a class of transposable elements capable of self-replication and insertion into new genomic locations. Across species, the mobilization of retrotransposons in somatic cells has been suggested to contribute to the cell and tissue functional decline that occurs during aging. Retrotransposons are broadly expressed across cell types, and de novo insertions have been observed to correlate with tumorigenesis. However, the extent to which new retrotransposon insertions occur during normal aging and their effect on cellular and animal function remains understudied. Here, we use a single nucleus whole genome sequencing approach in Drosophila to directly test whether transposon insertions increase with age in somatic cells. Analyses of nuclei from thoraces and indirect flight muscles using a newly developed pipeline, Retrofind, revealed no significant increase in the number of transposon insertions with age. Despite this, reducing the expression of two different retrotransposons, 412 and Roo, extended lifespan, but did not alter indicators of health such as stress resistance. This suggests a key role for transposon expression and not insertion in regulating longevity. Transcriptomic analyses revealed similar changes to gene expression in 412 and Roo knockdown flies and highlighted changes to genes involved in proteolysis and immune function as potential contributors to the observed changes in longevity. Combined, our data show a clear link between retrotransposon expression and aging.
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Affiliation(s)
- Blair K Schneider
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Ullmann 809 Bronx, NY 10461, USA
| | - Shixiang Sun
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Price 468 Bronx, NY 10461, USA
| | - Moonsook Lee
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Price 468 Bronx, NY 10461, USA
| | - Wenge Li
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Ullmann 909 Bronx, NY 10461, USA
| | - Nicholas Skvir
- Department of Molecular biology, Cell biology and Biochemistry, Brown University, 70 Ship St., Providence 02903, USA
| | - Nicola Neretti
- Department of Molecular biology, Cell biology and Biochemistry, Brown University, 70 Ship St., Providence 02903, USA
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Price 468 Bronx, NY 10461, USA
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Julie Secombe
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Ullmann 809 Bronx, NY 10461, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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10
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Wahl D, Smith ME, McEntee CM, Cavalier AN, Osburn SC, Burke SD, Grant RA, Nerguizian D, Lark DS, Link CD, LaRocca TJ. The reverse transcriptase inhibitor 3TC protects against age-related cognitive dysfunction. Aging Cell 2023; 22:e13798. [PMID: 36949552 PMCID: PMC10186603 DOI: 10.1111/acel.13798] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 03/24/2023] Open
Abstract
Aging is the primary risk factor for most neurodegenerative diseases, including Alzheimer's disease. Major hallmarks of brain aging include neuroinflammation/immune activation and reduced neuronal health/function. These processes contribute to cognitive dysfunction (a key risk factor for Alzheimer's disease), but their upstream causes are incompletely understood. Age-related increases in transposable element (TE) transcripts might contribute to reduced cognitive function with brain aging, as the reverse transcriptase inhibitor 3TC reduces inflammation in peripheral tissues and TE transcripts have been linked with tau pathology in Alzheimer's disease. However, the effects of 3TC on cognitive function with aging have not been investigated. Here, in support of a role for TE transcripts in brain aging/cognitive decline, we show that 3TC: (a) improves cognitive function and reduces neuroinflammation in old wild-type mice; (b) preserves neuronal health with aging in mice and Caenorhabditis elegans; and (c) enhances cognitive function in a mouse model of tauopathy. We also provide insight on potential underlying mechanisms, as well as evidence of translational relevance for these observations by showing that TE transcripts accumulate with brain aging in humans, and that these age-related increases intersect with those observed in Alzheimer's disease. Collectively, our results suggest that TE transcript accumulation during aging may contribute to cognitive decline and neurodegeneration, and that targeting these events with reverse transcriptase inhibitors like 3TC could be a viable therapeutic strategy.
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Affiliation(s)
- Devin Wahl
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - Meghan E. Smith
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - Cali M. McEntee
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - Alyssa N. Cavalier
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - Shelby C. Osburn
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - Samuel D. Burke
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - Randy A. Grant
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
| | - David Nerguizian
- Department of Biochemistry and Molecular GeneticsUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Daniel S. Lark
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
| | - Christopher D. Link
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderColoradoUSA
| | - Thomas J. LaRocca
- Department of Health and Exercise ScienceColorado State UniversityFort CollinsColoradoUSA
- Center for Healthy AgingColorado State UniversityFort CollinsColoradoUSA
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11
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Molecular Markers of Blood Cell Populations Can Help Estimate Aging of the Immune System. Int J Mol Sci 2023; 24:ijms24065708. [PMID: 36982782 PMCID: PMC10055688 DOI: 10.3390/ijms24065708] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
Aging of the immune system involves functional changes in individual cell populations, in hematopoietic tissues and at the systemic level. They are mediated by factors produced by circulating cells, niche cells, and at the systemic level. Age-related alterations in the microenvironment of the bone marrow and thymus cause a decrease in the production of naive immune cells and functional immunodeficiencies. Another result of aging and reduced tissue immune surveillance is the accumulation of senescent cells. Some viral infections deplete adaptive immune cells, increasing the risk of autoimmune and immunodeficiency conditions, leading to a general degradation in the specificity and effectiveness of the immune system in old age. During the COVID-19 pandemic, the state-of-the-art application of mass spectrometry, multichannel flow cytometry, and single-cell genetic analysis have provided vast data on the mechanisms of aging of the immune system. These data require systematic analysis and functional verification. In addition, the prediction of age-related complications is a priority task of modern medicine in the context of the increase in the aged population and the risk of premature death during epidemics. In this review, based on the latest data, we discuss the mechanisms of immune aging and highlight some cellular markers as indicators of age-related immune disbalance that increase the risk of senile diseases and infectious complications.
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12
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Gartland S, Zeng B, Marr MT. The small RNA landscape is stable with age and resistant to loss of dFOXO signaling in Drosophila. PLoS One 2022; 17:e0273590. [PMCID: PMC9668163 DOI: 10.1371/journal.pone.0273590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/18/2022] [Indexed: 11/17/2022] Open
Abstract
Aging can be defined as the progressive loss of physiological homeostasis that leads to a decline in cellular and organismal function. In recent years, it has become clear that small RNA pathways play a role in aging and aging related phenotypes. Small RNA pathways regulate many important processes including development, cellular physiology, and innate immunity. The pathways illicit a form of posttranscriptional gene regulation that relies on small RNAs bound by the protein components of the RNA-induced silencing complexes (RISCs), which inhibit the expression of complementary RNAs. In Drosophila melanogaster, Argonaute 1 (Ago1) is the core RISC component in microRNA (miRNA) silencing, while Argonaute 2 (Ago2) is the core RISC component in small interfering RNA (siRNA) silencing. The expression of Ago1 and Ago2 is regulated by stress response transcription factor Forkhead box O (dFOXO) increasing siRNA silencing efficiency. dFOXO plays a role in multiple stress responses and regulates pathways important for longevity. Here we use a next-generation sequencing approach to determine the effects of aging on small RNA abundance and RISC loading in male and female Drosophila. In addition, we examine the impact of the loss of dFOXO on these processes. We find that the relative abundance of the majority of small RNAs does not change with age. Additionally, under normal growth conditions, the loss of dFOXO has little effect on the small RNA landscape. However, we observed that age affects loading into RISC for a small number of miRNAs.
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Affiliation(s)
- Siobhan Gartland
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Baosheng Zeng
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Michael T. Marr
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
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