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Meyer DH, Schumacher B. Aging clocks based on accumulating stochastic variation. NATURE AGING 2024; 4:871-885. [PMID: 38724736 PMCID: PMC11186771 DOI: 10.1038/s43587-024-00619-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/28/2024] [Indexed: 05/15/2024]
Abstract
Aging clocks have provided one of the most important recent breakthroughs in the biology of aging, and may provide indicators for the effectiveness of interventions in the aging process and preventive treatments for age-related diseases. The reproducibility of accurate aging clocks has reinvigorated the debate on whether a programmed process underlies aging. Here we show that accumulating stochastic variation in purely simulated data is sufficient to build aging clocks, and that first-generation and second-generation aging clocks are compatible with the accumulation of stochastic variation in DNA methylation or transcriptomic data. We find that accumulating stochastic variation is sufficient to predict chronological and biological age, indicated by significant prediction differences in smoking, calorie restriction, heterochronic parabiosis and partial reprogramming. Although our simulations may not explicitly rule out a programmed aging process, our results suggest that stochastically accumulating changes in any set of data that have a ground state at age zero are sufficient for generating aging clocks.
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Affiliation(s)
- David H Meyer
- Institute for Genome Stability in Aging and Disease, University Hospital and University of Cologne, Cologne, Germany.
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
| | - Björn Schumacher
- Institute for Genome Stability in Aging and Disease, University Hospital and University of Cologne, Cologne, Germany.
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
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2
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Di Giorgio E, Ranzino L, Tolotto V, Dalla E, Burelli M, Gualandi N, Brancolini C. Transcription of endogenous retroviruses in senescent cells contributes to the accumulation of double-stranded RNAs that trigger an anti-viral response that reinforces senescence. Cell Death Dis 2024; 15:157. [PMID: 38383514 PMCID: PMC10882003 DOI: 10.1038/s41419-024-06548-2] [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: 06/08/2023] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 02/23/2024]
Abstract
An important epigenetic switch marks the onset and maintenance of senescence. This allows transcription of the genetic programs that arrest the cell cycle and alter the microenvironment. Transcription of endogenous retroviruses (ERVs) is also a consequence of this epigenetic switch. In this manuscript, we have identified a group of ERVs that are epigenetically silenced in proliferating cells but are upregulated during replicative senescence or during various forms of oncogene-induced senescence, by RAS and Akt, or after HDAC4 depletion. In a HDAC4 model of senescence, removal of the repressive histone mark H3K27me3 is the plausible mechanism that allows the transcription of intergenic ERVs during senescence. We have shown that ERVs contribute to the accumulation of dsRNAs in senescence, which can initiate the antiviral response via the IFIH1-MAVS signaling pathway and thus contribute to the maintenance of senescence. This pathway, and MAVS in particular, plays an active role in shaping the microenvironment and maintaining growth arrest, two essential features of the senescence program.
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Affiliation(s)
- Eros Di Giorgio
- Laboratory of Biochemistry, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Liliana Ranzino
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Vanessa Tolotto
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Emiliano Dalla
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Matteo Burelli
- Laboratory of Biochemistry, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Nicolò Gualandi
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Claudio Brancolini
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy.
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3
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Zhen Z, Chen Y, Wang H, Tang H, Zhang H, Liu H, Jiang Y, Mao Z. Nuclear cGAS restricts L1 retrotransposition by promoting TRIM41-mediated ORF2p ubiquitination and degradation. Nat Commun 2023; 14:8217. [PMID: 38086852 PMCID: PMC10716122 DOI: 10.1038/s41467-023-43001-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023] Open
Abstract
Cyclic GMP-AMP synthase (cGAS), initially identified as a cytosolic DNA sensor, detects DNA fragments to trigger an innate immune response. Recently, accumulating evidence reveals the presence of cGAS within the nucleus. However, the biological functions of nuclear cGAS are not fully understood. Here, we demonstrate that nuclear cGAS represses LINE-1 (L1) retrotransposition to preserve genome integrity in human cells. Mechanistically, the E3 ligase TRIM41 interacts with and ubiquitinates ORF2p to influence its stability, and cGAS enhances the association of ORF2p with TRIM41, thereby promoting TRIM41-mediated ORF2p degradation and the suppression of L1 retrotransposition. In response to DNA damage, cGAS is phosphorylated at serine residues 120 and 305 by CHK2, which promotes cGAS-TRIM41 association, facilitating TRIM41-mediated ORF2p degradation. Moreover, we show that nuclear cGAS mediates the repression of L1 retrotransposition in senescent cells induced by DNA damage agents. We also identify several cancer-associated cGAS mutations that abolish the suppressive effect on L1 retrotransposition by disrupting the CHK2-cGAS-TRIM41-ORF2p regulatory axis. Together, these findings indicate that nuclear cGAS exhibits an inhibitory function in L1 retrotransposition which could provide avenues for future interventions in both aging and tumorigenesis.
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Affiliation(s)
- Zhengyi Zhen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
- Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
- Tsingtao Advanced Research Institute, Tongji University, Qingdao, 266071, China
| | - Yu Chen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
- Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Haiyan Wang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
| | - Huanyin Tang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
| | - Haiping Zhang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
- Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Haipeng Liu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
| | - Ying Jiang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China
- Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Zhiyong Mao
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, 200092, Shanghai, China.
- Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China.
- Tsingtao Advanced Research Institute, Tongji University, Qingdao, 266071, China.
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4
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Jeong S, Cho S, Yang SK, Oh SA, Kang YK. Parallel shift of DNA methylation and gene expression toward the mean in mouse spleen with aging. Aging (Albany NY) 2023; 15:6690-6709. [PMID: 37494662 PMCID: PMC10415566 DOI: 10.18632/aging.204903] [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: 04/19/2023] [Accepted: 07/06/2023] [Indexed: 07/28/2023]
Abstract
Age-associated DNA-methylation drift (AMD) manifests itself in two ways in mammals: global decrease (hypomethylation) and local increase of DNA methylation (hypermethylation). To comprehend the principle behind this bidirectional AMD, we studied methylation states of spatially clustered CpG dinucleotides in mouse splenic DNA using reduced-representation-bisulfite-sequencing (RRBS). The mean methylation levels of whole CpGs declined with age. Promoter-resident CpGs, generally weakly methylated (<5%) in young mice, became hypermethylated in old mice, whereas CpGs in gene-body and intergenic regions, initially moderately (~33%) and extensively (>80%) methylated, respectively, were hypomethylated in the old. Chromosome-wise analysis of methylation revealed that inter-individual heterogeneities increase with age. The density of nearby CpGs was used to classify individual CpGs, which found hypermethylation in CpG-rich regions and hypomethylation in CpG-poor regions. When genomic regions were grouped by methylation level, high-methylation regions tended to become hypomethylated whereas low-methylation regions tended to become hypermethylated, regardless of genomic structure/function. Data analysis revealed that while methylation level and CpG density were interdependent, methylation level was a better predictor of the AMD pattern representing a shift toward the mean. Further analysis of gene-expression data showed a decrease in the expression of highly-expressed genes and an increase in the expression of lowly-expressed genes with age. This shift towards the mean in gene-expression changes was correlated with that of methylation changes, indicating a potential link between the two age-associated changes. Our findings suggest that age-associated hyper- and hypomethylation events are stochastic and attributed to malfunctioning intrinsic mechanisms for methylation maintenance in low- and high-methylation regions, respectively.
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Affiliation(s)
- Sangkyun Jeong
- Medical Research Division, Korea Institute of Oriental Medicine (KIOM), Yuseong-gu, Daejeon 34054, South Korea
- Genomics Department, Keyomics Co. Ltd., Yuseong-gu, Daejeon 34013, South Korea
| | - Sunwha Cho
- Genomics Department, Keyomics Co. Ltd., Yuseong-gu, Daejeon 34013, South Korea
| | - Seung Kyoung Yang
- Genomics Department, Keyomics Co. Ltd., Yuseong-gu, Daejeon 34013, South Korea
| | - Soo A. Oh
- Medical Research Division, Korea Institute of Oriental Medicine (KIOM), Yuseong-gu, Daejeon 34054, South Korea
| | - Yong-Kook Kang
- Development and Differentiation Research Center, Aging Convergence Research Center (ACRC), Korea Research Institute of Bioscience Biotechnology (KRIBB), Yuseong-gu, Daejeon 34141, South Korea
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5
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Ramini D, Latini S, Giuliani A, Matacchione G, Sabbatinelli J, Mensà E, Bacalini MG, Garagnani P, Rippo MR, Bronte G, Bonafè M, Cardelli M, Olivieri F. Replicative Senescence-Associated LINE1 Methylation and LINE1-Alu Expression Levels in Human Endothelial Cells. Cells 2022; 11:cells11233799. [PMID: 36497059 PMCID: PMC9739197 DOI: 10.3390/cells11233799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/22/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
One of the main challenges of current research on aging is to identify the complex epigenetic mechanisms involved in the acquisition of the cellular senescent phenotype. Despite some evidence suggested that epigenetic changes of DNA repetitive elements, including transposable elements (TE) sequences, are associated with replicative senescence of fibroblasts, data on different types of cells are scarce. We previously analysed genome-wide DNA methylation of young and replicative senescent human endothelial cells (HUVECs), highlighting increased levels of demethylated sequences in senescent cells. Here, we aligned the most significantly demethylated single CpG sites to the reference genome and annotated their localization inside TE sequences and found a significant hypomethylation of sequences belonging to the Long-Interspersed Element-1 (LINE-1 or L1) subfamilies L1M, L1P, and L1HS. To verify the hypothesis that L1 demethylation could be associated with increased transcription/activation of L1s and/or Alu elements (non-autonomous retroelements that usually depend on L1 sequences for reverse transcription and retrotransposition), we quantified the RNA expression levels of both L1 (generic L1 elements or site-specific L1PA2 on chromosome 14) and Alu elements in young and senescent HUVECs and human dermal fibroblasts (NHDFs). The RNA expression of Alu and L1 sequences was significantly increased in both senescent HUVECs and NHDFs, whereas the RNA transcript of L1PA2 on chromosome 14 was not significantly modulated in senescent cells. Moreover, we found an increased amount of TE DNA copies in the cytoplasm of senescent HUVECs and NHDFs. Our results support the hypothesis that TE, which are significantly increased in senescent cells, could be retrotranscribed to DNA sequences.
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Affiliation(s)
- Deborah Ramini
- Clinic of Laboratory and Precision Medicine, IRCCS INRCA, 60121 Ancona, Italy
| | - Silvia Latini
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
| | - Angelica Giuliani
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
- Correspondence: ; Tel.: +39-071-220-6243
| | - Giulia Matacchione
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
| | - Jacopo Sabbatinelli
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
- Laboratory Medicine Unit, Azienda Ospedaliero Universitaria delle Marche, 60126 Ancona, Italy
| | - Emanuela Mensà
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
| | | | - Paolo Garagnani
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, 40126 Bologna, Italy
- Applied Biomedical Research Center (CRBA), S. Orsola-Malpighi Polyclinic, 40126 Bologna, Italy
- CNR Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza”-Unit of Bologna, 40126 Bologna, Italy
- Department of Laboratory Medicine, Clinical Chemistry, Karolinska Institutet, Karolinska University Hospital, 141 86 Huddinge, Sweden
| | - Maria Rita Rippo
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
| | - Giuseppe Bronte
- Clinic of Laboratory and Precision Medicine, IRCCS INRCA, 60121 Ancona, Italy
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
| | - Massimiliano Bonafè
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, 40126 Bologna, Italy
| | - Maurizio Cardelli
- Advanced Technology Center for Aging Research, IRCCS INRCA, 60121 Ancona, Italy
| | - Fabiola Olivieri
- Clinic of Laboratory and Precision Medicine, IRCCS INRCA, 60121 Ancona, Italy
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, 60126 Ancona, Italy
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6
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The landscape of aging. SCIENCE CHINA LIFE SCIENCES 2022; 65:2354-2454. [PMID: 36066811 PMCID: PMC9446657 DOI: 10.1007/s11427-022-2161-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/05/2022] [Indexed: 02/07/2023]
Abstract
Aging is characterized by a progressive deterioration of physiological integrity, leading to impaired functional ability and ultimately increased susceptibility to death. It is a major risk factor for chronic human diseases, including cardiovascular disease, diabetes, neurological degeneration, and cancer. Therefore, the growing emphasis on “healthy aging” raises a series of important questions in life and social sciences. In recent years, there has been unprecedented progress in aging research, particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes. In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases, we review the descriptive, conceptual, and interventive aspects of the landscape of aging composed of a number of layers at the cellular, tissue, organ, organ system, and organismal levels.
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7
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Abstract
Over the course of a human lifespan, genome integrity erodes, leading to an increased abundance of several types of chromatin changes. The abundance of DNA lesions (chemical perturbations to nucleotides) increases with age, as does the number of genomic mutations and transcriptional disruptions caused by replication or transcription of those lesions, respectively. At the epigenetic level, precise DNA methylation patterns degrade, likely causing increasingly stochastic variations in gene expression. Similarly, the tight regulation of histone modifications begins to unravel. The genomic instability caused by these mechanisms allows transposon element reactivation and remobilization, further mutations, gene dysregulation, and cytoplasmic chromatin fragments. This cumulative genomic instability promotes cell signaling events that drive cell fate decisions and extracellular communications known to disrupt tissue homeostasis and regeneration. In this Review, we focus on age-related epigenetic changes and their interactions with age-related genomic changes that instigate these events.
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Affiliation(s)
- Carolina Soto-Palma
- Institute on the Biology of Aging and Metabolism
- Department of Biochemistry, Molecular Biology, and Biophysics
| | - Laura J. Niedernhofer
- Institute on the Biology of Aging and Metabolism
- Department of Biochemistry, Molecular Biology, and Biophysics
| | - Christopher D. Faulk
- Institute on the Biology of Aging and Metabolism
- Department of Animal Science, and
| | - Xiao Dong
- Institute on the Biology of Aging and Metabolism
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, USA
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8
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Loh D, Reiter RJ. Melatonin: Regulation of Viral Phase Separation and Epitranscriptomics in Post-Acute Sequelae of COVID-19. Int J Mol Sci 2022; 23:8122. [PMID: 35897696 PMCID: PMC9368024 DOI: 10.3390/ijms23158122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/09/2022] [Accepted: 07/20/2022] [Indexed: 01/27/2023] Open
Abstract
The relentless, protracted evolution of the SARS-CoV-2 virus imposes tremendous pressure on herd immunity and demands versatile adaptations by the human host genome to counter transcriptomic and epitranscriptomic alterations associated with a wide range of short- and long-term manifestations during acute infection and post-acute recovery, respectively. To promote viral replication during active infection and viral persistence, the SARS-CoV-2 envelope protein regulates host cell microenvironment including pH and ion concentrations to maintain a high oxidative environment that supports template switching, causing extensive mitochondrial damage and activation of pro-inflammatory cytokine signaling cascades. Oxidative stress and mitochondrial distress induce dynamic changes to both the host and viral RNA m6A methylome, and can trigger the derepression of long interspersed nuclear element 1 (LINE1), resulting in global hypomethylation, epigenetic changes, and genomic instability. The timely application of melatonin during early infection enhances host innate antiviral immune responses by preventing the formation of "viral factories" by nucleocapsid liquid-liquid phase separation that effectively blockades viral genome transcription and packaging, the disassembly of stress granules, and the sequestration of DEAD-box RNA helicases, including DDX3X, vital to immune signaling. Melatonin prevents membrane depolarization and protects cristae morphology to suppress glycolysis via antioxidant-dependent and -independent mechanisms. By restraining the derepression of LINE1 via multifaceted strategies, and maintaining the balance in m6A RNA modifications, melatonin could be the quintessential ancient molecule that significantly influences the outcome of the constant struggle between virus and host to gain transcriptomic and epitranscriptomic dominance over the host genome during acute infection and PASC.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA;
| | - Russel J. Reiter
- Department of Cell Systems and Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA
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Di Giorgio E, Xodo LE. Endogenous Retroviruses (ERVs): Does RLR (RIG-I-Like Receptors)-MAVS Pathway Directly Control Senescence and Aging as a Consequence of ERV De-Repression? Front Immunol 2022; 13:917998. [PMID: 35757716 PMCID: PMC9218063 DOI: 10.3389/fimmu.2022.917998] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Bi-directional transcription of Human Endogenous Retroviruses (hERVs) is a common feature of autoimmunity, neurodegeneration and cancer. Higher rates of cancer incidence, neurodegeneration and autoimmunity but a lower prevalence of autoimmune diseases characterize elderly people. Although the re-expression of hERVs is commonly observed in different cellular models of senescence as a result of the loss of their epigenetic transcriptional silencing, the hERVs modulation during aging is more complex, with a peak of activation in the sixties and a decline in the nineties. What is clearly accepted, instead, is the impact of the re-activation of dormant hERV on the maintenance of stemness and tissue self-renewing properties. An innate cellular immunity system, based on the RLR-MAVS circuit, controls the degradation of dsRNAs arising from the transcription of hERV elements, similarly to what happens for the accumulation of cytoplasmic DNA leading to the activation of cGAS/STING pathway. While agonists and inhibitors of the cGAS-STING pathway are considered promising immunomodulatory molecules, the effect of the RLR-MAVS pathway on innate immunity is still largely based on correlations and not on causality. Here we review the most recent evidence regarding the activation of MDA5-RIG1-MAVS pathway as a result of hERV de-repression during aging, immunosenescence, cancer and autoimmunity. We will also deal with the epigenetic mechanisms controlling hERV repression and with the strategies that can be adopted to modulate hERV expression in a therapeutic perspective. Finally, we will discuss if the RLR-MAVS signalling pathway actively modulates physiological and pathological conditions or if it is passively activated by them.
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Affiliation(s)
- Eros Di Giorgio
- Laboratory of Biochemistry, Department of Medicine, University of Udine, Udine, Italy
| | - Luigi E Xodo
- Laboratory of Biochemistry, Department of Medicine, University of Udine, Udine, Italy
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10
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Kang YK, Min B, Eom J, Park JS. Different phases of aging in mouse old skeletal muscle. Aging (Albany NY) 2022; 14:143-160. [PMID: 35017317 PMCID: PMC8791220 DOI: 10.18632/aging.203812] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 12/03/2021] [Indexed: 11/25/2022]
Abstract
With a graying population and increasing longevity, it is essential to identify life transition in later years and discern heterogeneity among older people. Subclassifying the elderly population to inspect the subdivisions for pathophysiological differences is particularly important for the investigation of age-related illnesses. For this purpose, using 24- and 28-month-old mice to represent the "young-old" and "old-old", respectively, we compared their skeletal muscle transcriptomes and found each in a distinct stage: early/gradual (E-aging) and late/accelerated aging phase (L-aging). Principal component analysis showed that the old-old transcriptomes were largely disengaged from the forward transcriptomic trajectory generated in the younger-aged group, indicating a substantial change in gene expression profiles during L-aging. By calculating the transcriptomic distance, it was found that the 28-month group was closer to the two-month group than to the 24-month group. The divergence rate per month for the transcriptomes was the highest in L-aging, twice as fast as the rate in E-aging. Indeed, many of the L-aging genes were significantly altered in transcription, although the changes did not seem random but rather coordinated in a variety of functional gene sets. Of 2,707 genes transcriptionally altered during E-aging, two-thirds were also significantly changed during L-aging, to either downturning or upturning way. The downturn genes were related to mitochondrial function and translational gene sets, while the upturn genes were linked to inflammation-associated gene sets. Our results provide a transcriptomic muscle signature that distinguishes old-old mice from young-old mice. This can help to methodically examine muscle disorders in the elderly.
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Affiliation(s)
- Yong-Kook Kang
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), Yuseong-Gu, Daejeon 34141, South Korea.,Department of Functional Genomics, Korea University of Science and Technology (UST), Yuseong-Gu, Daejeon 34113, South Korea
| | - Byungkuk Min
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), Yuseong-Gu, Daejeon 34141, South Korea
| | - Jaemin Eom
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), Yuseong-Gu, Daejeon 34141, South Korea.,Department of Functional Genomics, Korea University of Science and Technology (UST), Yuseong-Gu, Daejeon 34113, South Korea
| | - Jung Sun Park
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), Yuseong-Gu, Daejeon 34141, South Korea
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11
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Factors Regulating the Activity of LINE1 Retrotransposons. Genes (Basel) 2021; 12:genes12101562. [PMID: 34680956 PMCID: PMC8535693 DOI: 10.3390/genes12101562] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 12/15/2022] Open
Abstract
LINE-1 (L1) is a class of autonomous mobile genetic elements that form somatic mosaicisms in various tissues of the organism. The activity of L1 retrotransposons is strictly controlled by many factors in somatic and germ cells at all stages of ontogenesis. Alteration of L1 activity was noted in a number of diseases: in neuropsychiatric and autoimmune diseases, as well as in various forms of cancer. Altered activity of L1 retrotransposons for some pathologies is associated with epigenetic changes and defects in the genes involved in their repression. This review discusses the molecular genetic mechanisms of the retrotransposition and regulation of the activity of L1 elements. The contribution of various factors controlling the expression and distribution of L1 elements in the genome occurs at all stages of the retrotransposition. The regulation of L1 elements at the transcriptional, post-transcriptional and integration into the genome stages is described in detail. Finally, this review also focuses on the evolutionary aspects of L1 accumulation and their interplay with the host regulation system.
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12
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Kang YK, Min B. SETDB1 Overexpression Sets an Intertumoral Transcriptomic Divergence in Non-small Cell Lung Carcinoma. Front Genet 2020; 11:573515. [PMID: 33343623 PMCID: PMC7738479 DOI: 10.3389/fgene.2020.573515] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
An increasing volume of evidence suggests that SETDB1 plays a role in the tumorigenesis of various cancers, classifying SETDB1 as an oncoprotein. However, owing to its numerous protein partners and their global-scale effects, the molecular mechanism underlying SETDB1-involved oncogenesis remains ambiguous. In this study, using public transcriptome data of lung adenocarcinoma (ADC) and squamous-cell carcinoma (SCC), we compared tumors with high-level SETDB1 (SH) and those with low-level SETDB1 (comparable with normal samples; SL). The results of principal component analysis revealed a transcriptomic distinction and divergence between the SH and SL samples in both ADCs and SCCs. The results of gene set enrichment analysis indicated that genes involved in the “epithelial–mesenchymal transition,” “innate immune response,” and “autoimmunity” collections were significantly depleted in SH tumors, whereas those involved in “RNA interference” collections were enriched. Chromatin-modifying genes were highly expressed in SH tumors, and the variance in their expression was incomparably high in SCC-SH, which suggested greater heterogeneity within SCC tumors. DNA methyltransferase genes were also overrepresented in SH samples, and most differentially methylated CpGs (SH/SL) were undermethylated in a highly biased manner in ADCs. We identified interesting molecular signatures associated with the possible roles of SETDB1 in lung cancer. We expect these SETDB1-associated molecular signatures to facilitate the development of biologically relevant targeted therapies for particular types of lung cancer.
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Affiliation(s)
- Yong-Kook Kang
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology, Daejeon, South Korea.,Department of Functional Genomics, Korea University of Science and Technology, Daejeon, South Korea
| | - Byungkuk Min
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology, Daejeon, South Korea
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13
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Kuroki R, Murata Y, Fuke S, Nakachi Y, Nakashima J, Kujoth GC, Prolla TA, Bundo M, Kato T, Iwamoto K. Establishment of Quantitative PCR Assays for Active Long Interspersed Nuclear Element-1 Subfamilies in Mice and Applications to the Analysis of Aging-Associated Retrotransposition. Front Genet 2020; 11:519206. [PMID: 33193604 PMCID: PMC7525186 DOI: 10.3389/fgene.2020.519206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 08/20/2020] [Indexed: 01/01/2023] Open
Abstract
The retrotransposon long interspersed nuclear element-1 (LINE-1) can autonomously increase its copy number within a host genome through the retrotransposition process. LINE-1 is active in the germline and in neural progenitor cells, and its somatic retrotransposition activity has a broad impact on neural development and susceptibility to neuropsychiatric disorders. The method to quantify the genomic copy number of LINE-1 would be important in unraveling the role of retrotransposition, especially in the brain. However, because of the species-specific evolution of LINE-1 sequences, methods for quantifying the copy number should be independently developed. Here, we developed a quantitative PCR (qPCR) assay to measure the copy number of active LINE-1 subfamilies in mice. Using the assay, we investigated aging-associated alterations of LINE-1 copy number in several brain regions in wild-type mice and Polg+/D257A mice as a model for accelerated aging. We found that aged Polg+/D257A mice showed higher levels of the type GfII LINE-1 in the basal ganglia than the wild-type mice did, highlighting the importance of assays that focus on an individual active LINE-1 subfamily.
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Affiliation(s)
- Ryota Kuroki
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yui Murata
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Satoshi Fuke
- Lab for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Japan
| | - Yutaka Nakachi
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Jun Nakashima
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Gregory C Kujoth
- Department of Genetics and Medical Genetics, University of Wisconsin, Madison, WI, United States
| | - Tomas A Prolla
- Department of Genetics and Medical Genetics, University of Wisconsin, Madison, WI, United States
| | - Miki Bundo
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Tadafumi Kato
- Lab for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Japan
| | - Kazuya Iwamoto
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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14
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Min B, Park JS, Jeong YS, Jeon K, Kang YK. Dnmt1 binds and represses genomic retroelements via DNA methylation in mouse early embryos. Nucleic Acids Res 2020; 48:8431-8444. [PMID: 32667642 PMCID: PMC7470951 DOI: 10.1093/nar/gkaa584] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/10/2020] [Accepted: 07/03/2020] [Indexed: 12/12/2022] Open
Abstract
Genome-wide passive DNA demethylation in cleavage-stage mouse embryos is related to the cytoplasmic localization of the maintenance methyltransferase DNMT1. However, recent studies provided evidences of the nuclear localization of DNMT1 and its contribution to the maintenance of methylation levels of imprinted regions and other genomic loci in early embryos. Using the DNA adenine methylase identification method, we identified Dnmt1-binding regions in four- and eight-cell embryos. The unbiased distribution of Dnmt1 peaks in the genic regions (promoters and CpG islands) as well as the absence of a correlation between the Dnmt1 peaks and the expression levels of the peak-associated genes refutes the active participation of Dnmt1 in the transcriptional regulation of genes in the early developmental period. Instead, Dnmt1 was found to associate with genomic retroelements in a greatly biased fashion, particularly with the LINE1 (long interspersed nuclear elements) and ERVK (endogenous retrovirus type K) sequences. Transcriptomic analysis revealed that the transcripts of the Dnmt1-enriched retroelements were overrepresented in Dnmt1 knockdown embryos. Finally, methyl-CpG-binding domain sequencing proved that the Dnmt1-enriched retroelements, which were densely methylated in wild-type embryos, became demethylated in the Dnmt1-depleted embryos. Our results indicate that Dnmt1 is involved in the repression of retroelements through DNA methylation in early mouse development.
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Affiliation(s)
- Byungkuk Min
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Jung Sun Park
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Young Sun Jeong
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Kyuheum Jeon
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea.,Department of Functional Genomics, Korea University of Science and Technology, Daejeon 34113, South Korea
| | - Yong-Kook Kang
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea.,Department of Functional Genomics, Korea University of Science and Technology, Daejeon 34113, South Korea
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15
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Min B, Jeon K, Park JS, Kang Y. Demethylation and derepression of genomic retroelements in the skeletal muscles of aged mice. Aging Cell 2019; 18:e13042. [PMID: 31560164 PMCID: PMC6826136 DOI: 10.1111/acel.13042] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/07/2019] [Accepted: 08/30/2019] [Indexed: 12/13/2022] Open
Abstract
Changes in DNA methylation influence the aging process and contribute to aging phenotypes, but few studies have been conducted on DNA methylation changes in conjunction with skeletal muscle aging. We explored the DNA methylation changes in a variety of retroelement families throughout aging (at 2, 20, and 28 months of age) in murine skeletal muscles by methyl‐binding domain sequencing (MBD‐seq). The two following contrasting patterns were observed among the members of each repeat family in superaged mice: (a) hypermethylation in weakly methylated retroelement copies and (b) hypomethylation in copies with relatively stronger methylation levels, representing a pattern of “regression toward the mean” within a single retroelement family. Interestingly, these patterns depended on the sizes of the copies. While the majority of the elements showed a slight increase in methylation, the larger copies (>5 kb) displayed evident demethylation. All these changes were not observed in T cells. RNA sequencing revealed a global derepression of retroelements during the late phase of aging (between 20 and 28 months of age), which temporally coincided with retroelement demethylation. Following this methylation drift trend of “regression toward the mean,” aging tended to progressively lose the preexisting methylation differences and local patterns in the genomic regions that had been elaborately established during the early period of development.
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Affiliation(s)
- Byungkuk Min
- Development and Differentiation Research Center Korea Research Institute of Bioscience Biotechnology (KRIBB) Daejeon Korea
| | - Kyuheum Jeon
- Development and Differentiation Research Center Korea Research Institute of Bioscience Biotechnology (KRIBB) Daejeon Korea
- Department of Functional Genomics University of Science and Technology (UST) Daejeon Korea
| | - Jung Sun Park
- Development and Differentiation Research Center Korea Research Institute of Bioscience Biotechnology (KRIBB) Daejeon Korea
| | - Yong‐Kook Kang
- Development and Differentiation Research Center Korea Research Institute of Bioscience Biotechnology (KRIBB) Daejeon Korea
- Department of Functional Genomics University of Science and Technology (UST) Daejeon Korea
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