1
|
Bravo JI, Zhang L, Benayoun BA. Multi-ancestry GWAS reveals loci linked to human variation in LINE-1- and Alu-copy numbers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.10.612283. [PMID: 39314493 PMCID: PMC11419044 DOI: 10.1101/2024.09.10.612283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Long INterspersed Element-1 (LINE-1; L1) and Alu are two families of transposable elements (TEs) occupying ~17% and ~11% of the human genome, respectively. Though only a small fraction of L1 copies is able to produce the machinery to mobilize autonomously, Alu elements and degenerate L1 copies can hijack their functional machinery and mobilize in trans. The expression and subsequent copy number expansion of L1 and Alu can exert pathological effects on their hosts, promoting genome instability, inflammation, and cell cycle alterations. These features have made L1 and Alu promising focus subjects in studies of aging and aging diseases where they can become active. However, the mechanisms regulating variation in their expression and copy number remain incompletely characterized. Moreover, the relevance of known mechanisms to diverse human populations remains unclear, as mechanisms are often characterized in isogenic cell culture models. To address these gaps, we leveraged genomic data from the 1000 Genomes Project to carry out a trans-ethnic GWAS of L1 and Alu insertion global singletons. These singletons are rare insertions observed only once in a population, potentially reflecting recently acquired L1 and Alu integrants or structural variants, and which we used as proxies for L1/Alu-associated copy number variation. Our computational approach identified single nucleotide variants in genomic regions containing genes with potential and known TE regulatory properties, and it enriched for single nucleotide variants in regions containing known regulators of L1 expression. Moreover, we identified many reference TE copies and polymorphic structural variants that were associated with L1/Alu singletons, suggesting their potential contribution to TE copy number variation through transposition-dependent or transposition-independent mechanisms. Finally, a transcriptional analysis of lymphoblastoid cells highlighted potential cell cycle alterations in a subset of samples harboring L1/Alu singletons. Collectively, our results (i) suggest that known TE regulatory mechanisms may also play regulatory roles in diverse human populations, (ii) expand the list of genic and repetitive genomic loci implicated in TE copy number variation, and (iii) reinforce the links between TEs and disease.
Collapse
Affiliation(s)
- Juan I. Bravo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Lucia Zhang
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Quantitative and Computational Biology Department, USC Dornsife College of Letters, Arts and Sciences, Los Angeles, California, USA
| | - 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
| |
Collapse
|
2
|
Sran S, Ringland A, Bedrosian TA. Building the brain mosaic: an expanded view. Trends Genet 2024; 40:747-756. [PMID: 38853120 PMCID: PMC11387136 DOI: 10.1016/j.tig.2024.05.008] [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: 03/31/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/11/2024]
Abstract
The complexity of the brain is closely tied to its nature as a genetic mosaic, wherein each cell is distinguished by a unique constellation of somatic variants that contribute to functional and phenotypic diversity. Postzygotic variation arising during neurogenesis is recognized as a key contributor to brain mosaicism; however, recent advances have broadened our understanding to include sources of neural genomic diversity that develop throughout the entire lifespan, from embryogenesis through aging. Moving beyond the traditional confines of neurodevelopment, in this review, we delve into the complex mechanisms that enable various origins of brain mosaicism.
Collapse
Affiliation(s)
- Sahibjot Sran
- Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Amanda Ringland
- Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Tracy A Bedrosian
- Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
| |
Collapse
|
3
|
Betancourt AJ, Wei KHC, Huang Y, Lee YCG. Causes and Consequences of Varying Transposable Element Activity: An Evolutionary Perspective. Annu Rev Genomics Hum Genet 2024; 25:1-25. [PMID: 38603565 DOI: 10.1146/annurev-genom-120822-105708] [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: 04/13/2024]
Abstract
Transposable elements (TEs) are genomic parasites found in nearly all eukaryotes, including humans. This evolutionary success of TEs is due to their replicative activity, involving insertion into new genomic locations. TE activity varies at multiple levels, from between taxa to within individuals. The rapidly accumulating evidence of the influence of TE activity on human health, as well as the rapid growth of new tools to study it, motivated an evaluation of what we know about TE activity thus far. Here, we discuss why TE activity varies, and the consequences of this variation, from an evolutionary perspective. By studying TE activity in nonhuman organisms in the context of evolutionary theories, we can shed light on the factors that affect TE activity. While the consequences of TE activity are usually deleterious, some have lasting evolutionary impacts by conferring benefits on the host or affecting other evolutionary processes.
Collapse
Affiliation(s)
- Andrea J Betancourt
- Institute of Infection, Veterinary, and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Kevin H-C Wei
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yuheng Huang
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Yuh Chwen G Lee
- Center for Complex Biological Systems, University of California, Irvine, California, USA;
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| |
Collapse
|
4
|
Borgognone A, Casadellà M, Martínez de Lagrán M, Paredes R, Clotet B, Dierssen M, Elizalde-Torrent A. Lamivudine modulates the expression of neurological impairment-related genes and LINE-1 retrotransposons in brain tissues of a Down syndrome mouse model. Front Aging Neurosci 2024; 16:1386944. [PMID: 39100749 PMCID: PMC11294114 DOI: 10.3389/fnagi.2024.1386944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 07/05/2024] [Indexed: 08/06/2024] Open
Abstract
Elevated activity of retrotransposons is increasingly recognized to be implicated in a wide range of neurodegenerative and neurodevelopmental diseases, including Down syndrome (DS), which is the most common chromosomal condition causing intellectual disability globally. Previous research by our group has revealed that treatment with lamivudine, a reverse transcriptase inhibitor, improved neurobehavioral phenotypes and completely rescued hippocampal-dependent recognition memory in a DS mouse model, Ts65Dn. We hypothesized that retrotransposition rates would increase in the Ts65Dn mouse model, and lamivudine could block retrotransposons. We analyzed the differentially expressed long interspersed element-1 (LINE-1 or L1) mapping on MMU16 and 17, and showed for the first time that retrotransposition could be associated with Ts65Dn's pathology, as misregulation of L1 was found in brain tissues associated with trisomy. In the cerebral cortex, 6 out of 26 upregulated L1s in trisomic treated mice were located in the telomeric region of MMU16 near Ttc3, Kcnj6, and Dscam genes. In the hippocampus, one upregulated L1 element in trisomic treated mice was located near the Fgd4 gene on MMU16. Moreover, two downregulated L1s rescued after treatment with lamivudine were located in the intronic region of Nrxn1 (MMU17) and Snhg14 (MMU7), implicated in a variety of neurodegenerative disorders. To gain further insight into the mechanism of this improvement, we here analyzed the gene expression profile in the hippocampus and cerebral cortex of trisomic mice treated and no-treated with lamivudine compared to their wild-type littermates. We found that treatment with lamivudine rescued the expression of 24% of trisomic genes in the cortex (located on mouse chromosome (MMU) 16 and 17) and 15% in the hippocampus (located in the human chromosome 21 orthologous regions), with important DS candidate genes such as App and Ets2, rescued in both regions.
Collapse
Affiliation(s)
| | | | - María Martínez de Lagrán
- Center for Genomic Regulation, The Barcelona Institute for Science and Technology, Barcelona, Spain
| | - Roger Paredes
- IrsiCaixa, Badalona, Spain
- Department of Infeccious Diseases and Immunity, University of Vic-Central University of Catalonia (UVic-UCC), Vic, Spain
- CIBERINFEC, ISCIII, Madrid, Spain
- Department of Pathology, Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, United States
- Department of Infectious Diseases Service, Germans Trias i Pujol University Hospital, Badalona, Spain
- Fundació Lluita contra les Infeccions, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Bonaventura Clotet
- IrsiCaixa, Badalona, Spain
- Department of Infeccious Diseases and Immunity, University of Vic-Central University of Catalonia (UVic-UCC), Vic, Spain
- CIBERINFEC, ISCIII, Madrid, Spain
- Department of Infectious Diseases Service, Germans Trias i Pujol University Hospital, Badalona, Spain
- Fundació Lluita contra les Infeccions, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Mara Dierssen
- Center for Genomic Regulation, The Barcelona Institute for Science and Technology, Barcelona, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | | |
Collapse
|
5
|
Talley MJ, Longworth MS. Retrotransposons in embryogenesis and neurodevelopment. Biochem Soc Trans 2024; 52:1159-1171. [PMID: 38716891 PMCID: PMC11346457 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.
Collapse
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
| |
Collapse
|
6
|
Horváth V, Garza R, Jönsson ME, Johansson PA, Adami A, Christoforidou G, Karlsson O, Castilla Vallmanya L, Koutounidou S, Gerdes P, Pandiloski N, Douse CH, Jakobsson J. Mini-heterochromatin domains constrain the cis-regulatory impact of SVA transposons in human brain development and disease. Nat Struct Mol Biol 2024:10.1038/s41594-024-01320-8. [PMID: 38834915 DOI: 10.1038/s41594-024-01320-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/17/2024] [Indexed: 06/06/2024]
Abstract
SVA (SINE (short interspersed nuclear element)-VNTR (variable number of tandem repeats)-Alu) retrotransposons remain active in humans and contribute to individual genetic variation. Polymorphic SVA alleles harbor gene regulatory potential and can cause genetic disease. However, how SVA insertions are controlled and functionally impact human disease is unknown. Here we dissect the epigenetic regulation and influence of SVAs in cellular models of X-linked dystonia parkinsonism (XDP), a neurodegenerative disorder caused by an SVA insertion at the TAF1 locus. We demonstrate that the KRAB zinc finger protein ZNF91 establishes H3K9me3 and DNA methylation over SVAs, including polymorphic alleles, in human neural progenitor cells. The resulting mini-heterochromatin domains attenuate the cis-regulatory impact of SVAs. This is critical for XDP pathology; removal of local heterochromatin severely aggravates the XDP molecular phenotype, resulting in increased TAF1 intron retention and reduced expression. Our results provide unique mechanistic insights into how human polymorphic transposon insertions are recognized and how their regulatory impact is constrained by an innate epigenetic defense system.
Collapse
Affiliation(s)
- Vivien Horváth
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Raquel Garza
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Marie E Jönsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Pia A Johansson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Anita Adami
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Georgia Christoforidou
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Ofelia Karlsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Laura Castilla Vallmanya
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Symela Koutounidou
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Patricia Gerdes
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Ninoslav Pandiloski
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Christopher H Douse
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Johan Jakobsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden.
| |
Collapse
|
7
|
Janecki DM, Sen R, Szóstak N, Kajdasz A, Kordyś M, Plawgo K, Pandakov D, Philips A, Warkocki Z. LINE-1 mRNA 3' end dynamics shape its biology and retrotransposition potential. Nucleic Acids Res 2024; 52:3327-3345. [PMID: 38197223 PMCID: PMC11014359 DOI: 10.1093/nar/gkad1251] [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: 05/11/2023] [Revised: 12/16/2023] [Accepted: 12/20/2023] [Indexed: 01/11/2024] Open
Abstract
LINE-1 (L1) retrotransposons are mobile genetic elements that create new genomic insertions by a copy-paste mechanism involving L1 RNA/RNP intermediates. L1 encodes two ORFs, of which L1-ORF2p nicks genomic DNA and reverse transcribes L1 mRNA using the nicked DNA as a primer which base-pairs with poly(A) tail of L1 mRNA. To better understand the importance of non-templated L1 3' ends' dynamics and the interplay between L1 3' and 5' ends, we investigated the effects of genomic knock-outs and temporal knock-downs of XRN1, DCP2, and other factors. We hypothesized that in the absence of XRN1, the major 5'→3' exoribonuclease, there would be more L1 mRNA and retrotransposition. Conversely, we observed that loss of XRN1 decreased L1 retrotransposition. This occurred despite slight stabilization of L1 mRNA, but with decreased L1 RNP formation. Similarly, loss of DCP2, the catalytic subunit of the decapping complex, lowered retrotransposition despite increased steady-state levels of L1 proteins. In both XRN1 and DCP2 depletions we observed shortening of L1 3' poly(A) tails and their increased uridylation by TUT4/7. We explain the observed reduction of L1 retrotransposition by the changed qualities of non-templated L1 mRNA 3' ends demonstrating the important role of L1 3' end dynamics in L1 biology.
Collapse
Affiliation(s)
- Damian M Janecki
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Raneet Sen
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Natalia Szóstak
- Laboratory of Bioinformatics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Arkadiusz Kajdasz
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Martyna Kordyś
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Kinga Plawgo
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Dmytro Pandakov
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Anna Philips
- Laboratory of Bioinformatics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Zbigniew Warkocki
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| |
Collapse
|
8
|
Le Breton A, Bettencourt MP, Gendrel AV. Navigating the brain and aging: exploring the impact of transposable elements from health to disease. Front Cell Dev Biol 2024; 12:1357576. [PMID: 38476259 PMCID: PMC10927736 DOI: 10.3389/fcell.2024.1357576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/08/2024] [Indexed: 03/14/2024] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that constitute on average 45% of mammalian genomes. Their presence and activity in genomes represent a major source of genetic variability. While this is an important driver of genome evolution, TEs can also have deleterious effects on their hosts. A growing number of studies have focused on the role of TEs in the brain, both in physiological and pathological contexts. In the brain, their activity is believed to be important for neuronal plasticity. In neurological and age-related disorders, aberrant activity of TEs may contribute to disease etiology, although this remains unclear. After providing a comprehensive overview of transposable elements and their interactions with the host, this review summarizes the current understanding of TE activity within the brain, during the aging process, and in the context of neurological and age-related conditions.
Collapse
Affiliation(s)
| | | | - Anne-Valerie Gendrel
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
9
|
Lanciano S, Philippe C, Sarkar A, Pratella D, Domrane C, Doucet AJ, van Essen D, Saccani S, Ferry L, Defossez PA, Cristofari G. Locus-level L1 DNA methylation profiling reveals the epigenetic and transcriptional interplay between L1s and their integration sites. CELL GENOMICS 2024; 4:100498. [PMID: 38309261 PMCID: PMC10879037 DOI: 10.1016/j.xgen.2024.100498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/20/2023] [Accepted: 01/09/2024] [Indexed: 02/05/2024]
Abstract
Long interspersed element 1 (L1) retrotransposons are implicated in human disease and evolution. Their global activity is repressed by DNA methylation, but deciphering the regulation of individual copies has been challenging. Here, we combine short- and long-read sequencing to unveil L1 methylation heterogeneity across cell types, families, and individual loci and elucidate key principles involved. We find that the youngest primate L1 families are specifically hypomethylated in pluripotent stem cells and the placenta but not in most tumors. Locally, intronic L1 methylation is intimately associated with gene transcription. Conversely, the L1 methylation state can propagate to the proximal region up to 300 bp. This phenomenon is accompanied by the binding of specific transcription factors, which drive the expression of L1 and chimeric transcripts. Finally, L1 hypomethylation alone is typically insufficient to trigger L1 expression due to redundant silencing pathways. Our results illuminate the epigenetic and transcriptional interplay between retrotransposons and their host genome.
Collapse
Affiliation(s)
- Sophie Lanciano
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Claude Philippe
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Arpita Sarkar
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - David Pratella
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Cécilia Domrane
- University Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | - Aurélien J Doucet
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Dominic van Essen
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Simona Saccani
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Laure Ferry
- University Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | | | - Gael Cristofari
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France.
| |
Collapse
|
10
|
Singh S, Borkar MR, Bhatt LK. Transposable Elements: Emerging Therapeutic Targets in Neurodegenerative Diseases. Neurotox Res 2024; 42:9. [PMID: 38270797 DOI: 10.1007/s12640-024-00688-1] [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: 09/26/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are characterized by the progressive loss of neuronal function and structure. While several genetic and environmental factors have been implicated in the pathogenesis of these disorders, emerging evidence suggests that transposable elements (TEs), once considered "junk DNA," play a significant role in their development and progression. TEs are mobile genetic elements capable of moving within the genome, and their dysregulation has been associated with genomic instability, altered gene expression, and neuroinflammation. This review provides an overview of TEs, including long interspersed nuclear elements (LINEs), short interspersed nuclear elements (SINEs), and endogenous retroviruses (ERVs), mechanisms of repression and derepression, and their potential impact on neurodegeneration. The evidence linking TEs to AD, PD, and ALS by shedding light on the complex interactions between TEs and neurodegeneration has been discussed. Furthermore, the therapeutic potential of targeting TEs in neurodegenerative diseases has been explored. Understanding the role of TEs in neurodegeneration holds promise for developing novel therapeutic strategies aimed at mitigating disease progression and preserving neuronal health.
Collapse
Affiliation(s)
- Shrishti Singh
- Department of Pharmacology, Bhanuben Nanavati College of Pharmacy, SVKM's DrVile Parle (W), Mumbai, India
| | - Maheshkumar R Borkar
- Department of Pharmaceutical Chemistry, SVKM's Dr, Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India
| | - Lokesh Kumar Bhatt
- Department of Pharmacology, Bhanuben Nanavati College of Pharmacy, SVKM's DrVile Parle (W), Mumbai, India.
| |
Collapse
|
11
|
Martínez de Lagrán M, Bascón-Cardozo K, Dierssen M. Neurodevelopmental disorders: 2024 update. FREE NEUROPATHOLOGY 2024; 5:5-20. [PMID: 39252863 PMCID: PMC11382549 DOI: 10.17879/freeneuropathology-2024-5734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Accepted: 08/12/2024] [Indexed: 09/11/2024]
Abstract
Neurodevelopmental disorders encompass a range of conditions such as intellectual disability, autism spectrum disorder, rare genetic disorders and developmental and epileptic encephalopathies, all manifesting during childhood. Over 1,500 genes involved in various signaling pathways, including numerous transcriptional regulators, spliceosome elements, chromatin-modifying complexes and de novo variants have been recognized for their substantial role in these disorders. Along with new machine learning tools applied to neuroimaging, these discoveries facilitate genetic diagnoses, providing critical insights into neuropathological mechanisms and aiding in prognosis, and precision medicine. Also, new findings underscore the importance of understanding genetic contributions beyond protein-coding genes and emphasize the role of RNA and non-coding DNA molecules but also new players, such as transposable elements, whose dysregulation generates gene function disruption, epigenetic alteration, and genomic instability. Finally, recent developments in analyzing neuroimaging now offer the possibility of characterizing neuronal cytoarchitecture in vivo, presenting a viable alternative to traditional post-mortem studies. With a recently launched digital atlas of human fetal brain development, these new approaches will allow answering complex biological questions about fetal origins of cognitive function in childhood. In this review, we present ten fascinating topics where major progress has been made in the last year.
Collapse
Affiliation(s)
- María Martínez de Lagrán
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Karen Bascón-Cardozo
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Mara Dierssen
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain
- Biomedical Research Networking Center for Rare Diseases (CIBERER), Barcelona 08003, Spain
- Hospital del Mar Research Institute, Barcelona 08003, Spain
| |
Collapse
|
12
|
Mendez-Dorantes C, Burns KH. LINE-1 retrotransposition and its deregulation in cancers: implications for therapeutic opportunities. Genes Dev 2023; 37:948-967. [PMID: 38092519 PMCID: PMC10760644 DOI: 10.1101/gad.351051.123] [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] [Indexed: 12/28/2023]
Abstract
Long interspersed element 1 (LINE-1) is the only protein-coding transposon that is active in humans. LINE-1 propagates in the genome using RNA intermediates via retrotransposition. This activity has resulted in LINE-1 sequences occupying approximately one-fifth of our genome. Although most copies of LINE-1 are immobile, ∼100 copies are retrotransposition-competent. Retrotransposition is normally limited via epigenetic silencing, DNA repair, and other host defense mechanisms. In contrast, LINE-1 overexpression and retrotransposition are hallmarks of cancers. Here, we review mechanisms of LINE-1 regulation and how LINE-1 may promote genetic heterogeneity in tumors. Finally, we discuss therapeutic strategies to exploit LINE-1 biology in cancers.
Collapse
Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kathleen H Burns
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| |
Collapse
|
13
|
Smalheiser NR. Mobile circular DNAs regulating memory and communication in CNS neurons. Front Mol Neurosci 2023; 16:1304667. [PMID: 38125007 PMCID: PMC10730651 DOI: 10.3389/fnmol.2023.1304667] [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: 09/29/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023] Open
Abstract
Stimuli that stimulate neurons elicit transcription of immediate-early genes, a process which requires local sites of chromosomal DNA to form double-strand breaks (DSBs) generated by topoisomerase IIb within a few minutes, followed by repair within a few hours. Wakefulness, exploring a novel environment, and contextual fear conditioning also elicit turn-on of synaptic genes requiring DSBs and repair. It has been reported (in non-neuronal cells) that extrachromosomal circular DNA can form at DSBs as the sites are repaired. I propose that activated neurons may generate extrachromosomal circular DNAs during repair at DSB sites, thus creating long-lasting "markers" of that activity pattern which contain sequences from their sites of origin and which regulate long-term gene expression. Although the population of extrachromosomal DNAs is diverse and overall associated with pathology, a subclass of small circular DNAs ("microDNAs," ∼100-400 bases long), largely derives from unique genomic sequences and has attractive features to act as stable, mobile circular DNAs to regulate gene expression in a sequence-specific manner. Circular DNAs can be templates for the transcription of RNAs, particularly small inhibitory siRNAs, circular RNAs and other non-coding RNAs that interact with microRNAs. These may regulate translation and transcription of other genes involved in synaptic plasticity, learning and memory. Another possible fate for mobile DNAs is to be inserted stably into chromosomes after new DSB sites are generated in response to subsequent activation events. Thus, the insertions of mobile DNAs into activity-induced genes may tend to inactivate them and aid in homeostatic regulation to avoid over-excitation, as well as providing a "counter" for a neuron's activation history. Moreover, activated neurons release secretory exosomes that can be transferred to recipient cells to regulate their gene expression. Mobile DNAs may be packaged into exosomes, released in an activity-dependent manner, and transferred to recipient cells, where they may be templates for regulatory RNAs and possibly incorporated into chromosomes. Finally, aging and neurodegenerative diseases (including Alzheimer's disease) are also associated with an increase in DSBs in neurons. It will become important in the future to assess how pathology-associated DSBs may relate to activity-induced mobile DNAs, and whether the latter may potentially contribute to pathogenesis.
Collapse
Affiliation(s)
- Neil R. Smalheiser
- Department of Psychiatry, University of Illinois College of Medicine, Chicago, IL, United States
| |
Collapse
|
14
|
Tooley KB, Chucair-Elliott AJ, Ocañas SR, Machalinski AH, Pham KD, Hoolehan W, Kulpa AM, Stanford DR, Freeman WM. Differential usage of DNA modifications in neurons, astrocytes, and microglia. Epigenetics Chromatin 2023; 16:45. [PMID: 37953264 PMCID: PMC10642035 DOI: 10.1186/s13072-023-00522-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 11/06/2023] [Indexed: 11/14/2023] Open
Abstract
BACKGROUND Cellular identity is determined partly by cell type-specific epigenomic profiles that regulate gene expression. In neuroscience, there is a pressing need to isolate and characterize the epigenomes of specific CNS cell types in health and disease. In this study, we developed an in vivo tagging mouse model (Camk2a-NuTRAP) for paired isolation of neuronal DNA and RNA without cell sorting and then used this model to assess epigenomic regulation, DNA modifications in particular, of gene expression between neurons and glia. RESULTS After validating the cell-specificity of the Camk2a-NuTRAP model, we performed TRAP-RNA-Seq and INTACT-whole genome oxidative bisulfite sequencing (WGoxBS) to assess the neuronal translatome and epigenome in the hippocampus of young mice (4 months old). WGoxBS findings were validated with enzymatic methyl-Seq (EM-Seq) and nanopore sequencing. Comparing neuronal data to microglial and astrocytic data from NuTRAP models, microglia had the highest global mCG levels followed by astrocytes and then neurons, with the opposite pattern observed for hmCG and mCH. Differentially modified regions between cell types were predominantly found within gene bodies and distal intergenic regions, rather than proximal promoters. Across cell types there was a negative correlation between DNA modifications (mCG, mCH, hmCG) and gene expression at proximal promoters. In contrast, a negative correlation of gene body mCG and a positive relationship between distal promoter and gene body hmCG with gene expression was observed. Furthermore, we identified a neuron-specific inverse relationship between mCH and gene expression across promoter and gene body regions. CONCLUSIONS Neurons, astrocytes, and microglia demonstrate different genome-wide levels of mCG, hmCG, and mCH that are reproducible across analytical methods. However, modification-gene expression relationships are conserved across cell types. Enrichment of differential modifications across cell types in gene bodies and distal regulatory elements, but not proximal promoters, highlights epigenomic patterning in these regions as potentially greater determinants of cell identity. These findings also demonstrate the importance of differentiating between mC and hmC in neuroepigenomic analyses, as up to 30% of what is conventionally interpreted as mCG can be hmCG, which often has a different relationship to gene expression than mCG.
Collapse
Affiliation(s)
- Kyla B Tooley
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - Ana J Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - Sarah R Ocañas
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - Adeline H Machalinski
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - Kevin D Pham
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - Walker Hoolehan
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - Adam M Kulpa
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK, 73104, USA
| | - David R Stanford
- Center for Biomedical Data Sciences, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Willard M Freeman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Biochemistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA.
| |
Collapse
|
15
|
Ding J, Wang S, Liu Q, Duan Y, Cheng T, Ye Z, Cui Z, Zhang A, Liu Q, Zhang Z, Zhang N, Liu Q, An N, Zhao J, Yi D, Li Q, Wang J, Zhang Y, Ma L, Guo S, Wang J, Liang C, Zhou J, Cen S, Li X. Schlafen-5 inhibits LINE-1 retrotransposition. iScience 2023; 26:107968. [PMID: 37810251 PMCID: PMC10551903 DOI: 10.1016/j.isci.2023.107968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 07/20/2023] [Accepted: 09/15/2023] [Indexed: 10/10/2023] Open
Abstract
Long interspersed element 1 (LINE-1) is the only currently known active autonomous transposon in humans, and its retrotransposition may cause deleterious effects on the structure and function of host cell genomes and result in sporadic genetic diseases. Host cells therefore developed defense strategies to restrict LINE-1 mobilization. In this study, we demonstrated that IFN-inducible Schlafen5 (SLFN5) inhibits LINE-1 retrotransposition. Mechanistic studies revealed that SLFN5 interrupts LINE-1 ribonucleoprotein particle (RNP) formation, thus diminishing nuclear entry of the LINE-1 RNA template and subsequent LINE-1 cDNA production. The ability of SLFN5 to bind to LINE-1 RNA and the involvement of the helicase domain of SLFN5 in its inhibitory activity suggest a mechanism that SLFN5 binds to LINE-1 RNA followed by dissociation of ORF1p through its helicase activity, resulting in impaired RNP formation. These data highlight a new mechanism of host cells to restrict LINE-1 mobilization.
Collapse
Affiliation(s)
- Jiwei Ding
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Shujie Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Qipeng Liu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yuqing Duan
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Tingting Cheng
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhongjie Ye
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhanding Cui
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ao Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Qiuyu Liu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zixiong Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ning Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Qian Liu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ni An
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jianyuan Zhao
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Dongrong Yi
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Quanjie Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jing Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yongxin Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ling Ma
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Saisai Guo
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jinhui Wang
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Chen Liang
- The Lady Davis Institute-Jewish General Hospital, Montreal, QC H3T 1E2, Canada
| | - Jinming Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xiaoyu Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| |
Collapse
|
16
|
Cheng KCL, Frost JM, Sánchez-Luque FJ, García-Canãdas M, Taylor D, Yang WR, Irayanar B, Sampath S, Patani H, Agger K, Helin K, Ficz G, Burns KH, Ewing A, García-Pérez JL, Branco MR. Vitamin C activates young LINE-1 elements in mouse embryonic stem cells via H3K9me3 demethylation. Epigenetics Chromatin 2023; 16:39. [PMID: 37845773 PMCID: PMC10578016 DOI: 10.1186/s13072-023-00514-6] [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: 08/07/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND Vitamin C (vitC) enhances the activity of 2-oxoglutarate-dependent dioxygenases, including TET enzymes, which catalyse DNA demethylation, and Jumonji-domain histone demethylases. The epigenetic remodelling promoted by vitC improves the efficiency of induced pluripotent stem cell derivation, and is required to attain a ground-state of pluripotency in embryonic stem cells (ESCs) that closely mimics the inner cell mass of the early blastocyst. However, genome-wide DNA and histone demethylation can lead to upregulation of transposable elements (TEs), and it is not known how vitC addition in culture media affects TE expression in pluripotent stem cells. RESULTS Here we show that vitC increases the expression of several TE families, including evolutionarily young LINE-1 (L1) elements, in mouse ESCs. We find that TET activity is dispensable for L1 upregulation, and that instead it occurs largely as a result of H3K9me3 loss mediated by KDM4A/C histone demethylases. Despite increased L1 levels, we did not detect increased somatic insertion rates in vitC-treated cells. Notably, treatment of human ESCs with vitC also increases L1 protein levels, albeit through a distinct, post-transcriptional mechanism. CONCLUSION VitC directly modulates the expression of mouse L1s and other TEs through epigenetic mechanisms, with potential for downstream effects related to the multiple emerging roles of L1s in cellular function.
Collapse
Affiliation(s)
- Kevin C L Cheng
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
- Computational Biology Program, Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Jennifer M Frost
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Francisco J Sánchez-Luque
- Institute of Parasitology and Biomedicine "Lopez-Neyra" (IPBLN), Spanish National Research Council (CSIC), PTS Granada, Granada, Spain
| | - Marta García-Canãdas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Darren Taylor
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
- MRC London Institute of Medical Sciences, London, W12 0NN, UK
| | - Wan R Yang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Branavy Irayanar
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Swetha Sampath
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Hemalvi Patani
- Barts Cancer Institute, Faculty of Medicine and Dentistry, QMUL, London, EC1M 6BQ, UK
| | - Karl Agger
- The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen, Denmark
| | - Kristian Helin
- The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen, Denmark
- The Institute of Cancer Research, London, UK
| | - Gabriella Ficz
- Barts Cancer Institute, Faculty of Medicine and Dentistry, QMUL, London, EC1M 6BQ, UK
| | - Kathleen H Burns
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Adam Ewing
- Mater Research Institute, University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - José L García-Pérez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Miguel R Branco
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK.
| |
Collapse
|
17
|
Luqman-Fatah A, Miyoshi T. Human LINE-1 retrotransposons: impacts on the genome and regulation by host factors. Genes Genet Syst 2023; 98:121-154. [PMID: 36436935 DOI: 10.1266/ggs.22-00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Genome sequencing revealed that nearly half of the human genome is comprised of transposable elements. Although most of these elements have been rendered inactive due to mutations, full-length intact long interspersed element-1 (LINE-1 or L1) copies retain the ability to mobilize through RNA intermediates by a so-called "copy-and-paste" mechanism, termed retrotransposition. L1 is the only known autonomous mobile genetic element in the genome, and its retrotransposition contributes to inter- or intra-individual genetic variation within the human population. However, L1 retrotransposition also poses a threat to genome integrity due to gene disruption and chromosomal instability. Moreover, recent studies suggest that aberrant L1 expression can impact human health by causing diseases such as cancer and chronic inflammation that might lead to autoimmune disorders. To counteract these adverse effects, the host cells have evolved multiple layers of defense mechanisms at the epigenetic, RNA and protein levels. Intriguingly, several host factors have also been reported to facilitate L1 retrotransposition, suggesting that there is competition between negative and positive regulation of L1 by host factors. Here, we summarize the known host proteins that regulate L1 activity at different stages of the replication cycle and discuss how these factors modulate disease-associated phenotypes caused by L1.
Collapse
Affiliation(s)
- Ahmad Luqman-Fatah
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
| | - Tomoichiro Miyoshi
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
| |
Collapse
|
18
|
Gerdes P, Chan D, Lundberg M, Sanchez-Luque FJ, Bodea GO, Ewing AD, Faulkner GJ, Richardson SR. Locus-resolution analysis of L1 regulation and retrotransposition potential in mouse embryonic development. Genome Res 2023; 33:1465-1481. [PMID: 37798118 PMCID: PMC10620060 DOI: 10.1101/gr.278003.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023]
Abstract
Mice harbor ∼2800 intact copies of the retrotransposon Long Interspersed Element 1 (L1). The in vivo retrotransposition capacity of an L1 copy is defined by both its sequence integrity and epigenetic status, including DNA methylation of the monomeric units constituting young mouse L1 promoters. Locus-specific L1 methylation dynamics during development may therefore elucidate and explain spatiotemporal niches of endogenous retrotransposition but remain unresolved. Here, we interrogate the retrotransposition efficiency and epigenetic fate of source (donor) L1s, identified as mobile in vivo. We show that promoter monomer loss consistently attenuates the relative retrotransposition potential of their offspring (daughter) L1 insertions. We also observe that most donor/daughter L1 pairs are efficiently methylated upon differentiation in vivo and in vitro. We use Oxford Nanopore Technologies (ONT) long-read sequencing to resolve L1 methylation genome-wide and at individual L1 loci, revealing a distinctive "smile" pattern in methylation levels across the L1 promoter region. Using Pacific Biosciences (PacBio) SMRT sequencing of L1 5' RACE products, we then examine DNA methylation dynamics at the mouse L1 promoter in parallel with transcription start site (TSS) distribution at locus-specific resolution. Together, our results offer a novel perspective on the interplay between epigenetic repression, L1 evolution, and genome stability.
Collapse
Affiliation(s)
- Patricia Gerdes
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Dorothy Chan
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Mischa Lundberg
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, Queensland 4102, Australia
- Translational Bioinformatics, Commonwealth Scientific and Industrial Research Organisation, Sydney, New South Wales 2113, Australia
| | - Francisco J Sanchez-Luque
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- GENYO. Centre for Genomics and Oncological Research (Pfizer-University of Granada-Andalusian Regional Government), PTS Granada, 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
| | - Gabriela O Bodea
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Adam D Ewing
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia;
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sandra R Richardson
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia;
| |
Collapse
|
19
|
Berteli TS, Wang F, Navarro PA, Kohlrausch FB, Keefe DL. A pilot study of LINE-1 copy number and telomere length with aging in human sperm. J Assist Reprod Genet 2023; 40:1845-1854. [PMID: 37382785 PMCID: PMC10371944 DOI: 10.1007/s10815-023-02857-1] [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: 03/27/2023] [Accepted: 06/03/2023] [Indexed: 06/30/2023] Open
Abstract
PURPOSE Unlike other cells in the body, in sperm, telomere length (TL) increases with age. TL can regulate nearby genes, and the subtelomeric region is rich in retrotransposons. We hypothesized that age-related telomere lengthening in sperm might suppress Long Interspersed Element 1 (LINE-1/L1), the only competent retrotransposon in humans. METHODS We measured L1 copy number (L1-CN) and sperm telomere length (STL) from young and older men to evaluate the relationship between age, TL and L1-CN. We also evaluated L1-CN and TL in individual sperm to determine whether these variables influence sperm morphology. STL was assayed by Multiplex quantitative polymerase chain reaction method (mmqPCR) and L1-CN by Quantitative polymerase chain reaction (qPCR). RESULTS We found that STL increased, and L1-CN decreased significantly with paternal age. STL in normal single sperm was significantly higher than in abnormal sperm. L1-CN did not differ between normal and abnormal sperm. Furthermore, morphologically normal sperm have longer telomeres than abnormal sperm. CONCLUSIONS Elongation of telomeres in the male germline could repress retrotransposition, which tends to increase with cellular aging. More studies in larger cohorts across a wide age span are needed to confirm our conclusions and explore their biological and clinical significance.
Collapse
Affiliation(s)
- Thalita S Berteli
- Department of Obstetrics and Gynecology, Langone Medical Center, New York University, 462, 1st Avenue, New York, NY, 10016, USA.
- Human Reproduction Division, Department of Gynecology and Obstetrics, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
| | - Fang Wang
- Department of Obstetrics and Gynecology, Langone Medical Center, New York University, 462, 1st Avenue, New York, NY, 10016, USA
| | - Paula A Navarro
- Human Reproduction Division, Department of Gynecology and Obstetrics, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Fabiana B Kohlrausch
- Department of Obstetrics and Gynecology, Langone Medical Center, New York University, 462, 1st Avenue, New York, NY, 10016, USA
- Human Genetics Laboratory, Fluminense Federal University, Niteroi, RJ, Brazil
| | - David L Keefe
- Department of Obstetrics and Gynecology, Langone Medical Center, New York University, 462, 1st Avenue, New York, NY, 10016, USA
| |
Collapse
|
20
|
Goodier JL, Wan H, Soares AO, Sanchez L, Selser JM, Pereira GC, Karma S, García-Pérez JL, Kazazian HH, García Cañadas MM. ZCCHC3 is a stress granule zinc knuckle protein that strongly suppresses LINE-1 retrotransposition. PLoS Genet 2023; 19:e1010795. [PMID: 37405998 DOI: 10.1371/journal.pgen.1010795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 05/23/2023] [Indexed: 07/07/2023] Open
Abstract
Retrotransposons have generated about half of the human genome and LINE-1s (L1s) are the only autonomously active retrotransposons. The cell has evolved an arsenal of defense mechanisms to protect against retrotransposition with factors we are only beginning to understand. In this study, we investigate Zinc Finger CCHC-Type Containing 3 (ZCCHC3), a gag-like zinc knuckle protein recently reported to function in the innate immune response to infecting viruses. We show that ZCCHC3 also severely restricts human retrotransposons and associates with the L1 ORF1p ribonucleoprotein particle. We identify ZCCHC3 as a bona fide stress granule protein, and its association with LINE-1 is further supported by colocalization with L1 ORF1 protein in stress granules, dense cytoplasmic aggregations of proteins and RNAs that contain stalled translation pre-initiation complexes and form when the cell is under stress. Our work also draws links between ZCCHC3 and the anti-viral and retrotransposon restriction factors Mov10 RISC Complex RNA Helicase (MOV10) and Zinc Finger CCCH-Type, Antiviral 1 (ZC3HAV1, also called ZAP). Furthermore, collective evidence from subcellular localization, co-immunoprecipitation, and velocity gradient centrifugation connects ZCCHC3 with the RNA exosome, a multi-subunit ribonuclease complex capable of degrading various species of RNA molecules and that has previously been linked with retrotransposon control.
Collapse
Affiliation(s)
- John L Goodier
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Han Wan
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alisha O Soares
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Laura Sanchez
- GENYO, Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - John Michael Selser
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Gavin C Pereira
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sadik Karma
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jose Luis García-Pérez
- GENYO, Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Haig H Kazazian
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Marta M García Cañadas
- GENYO, Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| |
Collapse
|
21
|
Pal D, Patel M, Boulet F, Sundarraj J, Grant OA, Branco MR, Basu S, Santos SDM, Zabet NR, Scaffidi P, Pradeepa MM. H4K16ac activates the transcription of transposable elements and contributes to their cis-regulatory function. Nat Struct Mol Biol 2023; 30:935-947. [PMID: 37308596 PMCID: PMC10352135 DOI: 10.1038/s41594-023-01016-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 05/05/2023] [Indexed: 06/14/2023]
Abstract
Mammalian genomes harbor abundant transposable elements (TEs) and their remnants, with numerous epigenetic repression mechanisms enacted to silence TE transcription. However, TEs are upregulated during early development, neuronal lineage, and cancers, although the epigenetic factors contributing to the transcription of TEs have yet to be fully elucidated. Here, we demonstrate that the male-specific lethal (MSL)-complex-mediated histone H4 acetylation at lysine 16 (H4K16ac) is enriched at TEs in human embryonic stem cells (hESCs) and cancer cells. This in turn activates transcription of subsets of full-length long interspersed nuclear elements (LINE1s, L1s) and endogenous retrovirus (ERV) long terminal repeats (LTRs). Furthermore, we show that the H4K16ac-marked L1 and LTR subfamilies display enhancer-like functions and are enriched in genomic locations with chromatin features associated with active enhancers. Importantly, such regions often reside at boundaries of topologically associated domains and loop with genes. CRISPR-based epigenetic perturbation and genetic deletion of L1s reveal that H4K16ac-marked L1s and LTRs regulate the expression of genes in cis. Overall, TEs enriched with H4K16ac contribute to the cis-regulatory landscape at specific genomic locations by maintaining an active chromatin landscape at TEs.
Collapse
Affiliation(s)
- Debosree Pal
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Manthan Patel
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Fanny Boulet
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Jayakumar Sundarraj
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
- Bhabha Atomic Research Centre, Mumbai, India
| | - Olivia A Grant
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
- School of Life Sciences, University of Essex, Colchester, UK
| | - Miguel R Branco
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Srinjan Basu
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | | | - Nicolae Radu Zabet
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Paola Scaffidi
- Francis Crick Institute, London, UK
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Madapura M Pradeepa
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK.
| |
Collapse
|
22
|
Tooley KB, Chucair-Elliott AJ, Ocañas SR, Machalinski AH, Pham KD, Stanford DR, Freeman WM. Differential usage of DNA modifications in neurons, astrocytes, and microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543497. [PMID: 37333391 PMCID: PMC10274634 DOI: 10.1101/2023.06.05.543497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background Cellular identity is determined partly by cell type-specific epigenomic profiles that regulate gene expression. In neuroscience, there is a pressing need to isolate and characterize the epigenomes of specific CNS cell types in health and disease. This is especially true as for DNA modifications where most data are derived from bisulfite sequencing that cannot differentiate between DNA methylation and hydroxymethylation. In this study, we developed an in vivo tagging mouse model (Camk2a-NuTRAP) for paired isolation of neuronal DNA and RNA without cell sorting and then used this model to assess epigenomic regulation of gene expression between neurons and glia. Results After validating the cell-specificity of the Camk2a-NuTRAP model, we performed TRAP-RNA-Seq and INTACT whole genome oxidative bisulfite sequencing to assess the neuronal translatome and epigenome in the hippocampus of young mice (3 months old). These data were then compared to microglial and astrocytic data from NuTRAP models. When comparing the different cell types, microglia had the highest global mCG levels followed by astrocytes and then neurons, with the opposite pattern observed for hmCG and mCH. Differentially modified regions between cell types were predominantly found within gene bodies and distal intergenic regions, with limited differences occurring within proximal promoters. Across cell types there was a negative correlation between DNA modifications (mCG, mCH, hmCG) and gene expression at proximal promoters. In contrast, a negative correlation of mCG with gene expression within the gene body while a positive relationship between distal promoter and gene body hmCG and gene expression was observed. Furthermore, we identified a neuron-specific inverse relationship between mCH and gene expression across promoter and gene body regions. Conclusions In this study, we identified differential usage of DNA modifications across CNS cell types, and assessed the relationship between DNA modifications and gene expression in neurons and glia. Despite having different global levels, the general modification-gene expression relationship was conserved across cell types. The enrichment of differential modifications in gene bodies and distal regulatory elements, but not proximal promoters, across cell types highlights epigenomic patterning in these regions as potentially greater determinants of cell identity.
Collapse
Affiliation(s)
- Kyla B. Tooley
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Ana J. Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Sarah R. Ocañas
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Adeline H. Machalinski
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Kevin D. Pham
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - David R. Stanford
- Center for Biomedical Data Sciences, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Willard M. Freeman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
- Department of Biochemistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK USA
| |
Collapse
|
23
|
Singh M, Kondrashkina AM, Widmann TJ, Cortes JL, Bansal V, Wang J, Römer C, Garcia-Canadas M, Garcia-Perez JL, Hurst LD, Izsvák Z. A new human embryonic cell type associated with activity of young transposable elements allows definition of the inner cell mass. PLoS Biol 2023; 21:e3002162. [PMID: 37339119 DOI: 10.1371/journal.pbio.3002162] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 05/12/2023] [Indexed: 06/22/2023] Open
Abstract
There remains much that we do not understand about the earliest stages of human development. On a gross level, there is evidence for apoptosis, but the nature of the affected cell types is unknown. Perhaps most importantly, the inner cell mass (ICM), from which the foetus is derived and hence of interest in reproductive health and regenerative medicine, has proven hard to define. Here, we provide a multi-method analysis of the early human embryo to resolve these issues. Single-cell analysis (on multiple independent datasets), supported by embryo visualisation, uncovers a common previously uncharacterised class of cells lacking commitment markers that segregates after embryonic gene activation (EGA) and shortly after undergo apoptosis. The discovery of this cell type allows us to clearly define their viable ontogenetic sisters, these being the cells of the ICM. While ICM is characterised by the activity of an Old non-transposing endogenous retrovirus (HERVH) that acts to suppress Young transposable elements, the new cell type, by contrast, expresses transpositionally competent Young elements and DNA-damage response genes. As the Young elements are RetroElements and the cells are excluded from the developmental process, we dub these REject cells. With these and ICM being characterised by differential mobile element activities, the human embryo may be a "selection arena" in which one group of cells selectively die, while other less damaged cells persist.
Collapse
Affiliation(s)
- Manvendra Singh
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
- Max Planck Institute of Multidisciplinary Sciences, City Campus, Göttingen, Germany
| | | | - Thomas J Widmann
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
| | - Jose L Cortes
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
| | - Vikas Bansal
- German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Jichang Wang
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
| | - Christine Römer
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
| | - Marta Garcia-Canadas
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
| | - Jose L Garcia-Perez
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
- Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Crewe Road, Edinburgh, United Kingdom
| | - Laurence D Hurst
- The Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - Zsuzsanna Izsvák
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
| |
Collapse
|
24
|
Wang F, McCulloh DH, Chan K, Wiltshire A, McCaffrey C, Grifo JA, Keefe DL. The Landscape of Telomere Length and Telomerase in Human Embryos at Blastocyst Stage. Genes (Basel) 2023; 14:1200. [PMID: 37372380 DOI: 10.3390/genes14061200] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/19/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
The telomere length of human blastocysts exceeds that of oocytes and telomerase activity increases after zygotic activation, peaking at the blastocyst stage. Yet, it is unknown whether aneuploid human embryos at the blastocyst stage exhibit a different profile of telomere length, telomerase gene expression, and telomerase activity compared to euploid embryos. In present study, 154 cryopreserved human blastocysts, donated by consenting patients, were thawed and assayed for telomere length, telomerase gene expression, and telomerase activity using real-time PCR (qPCR) and immunofluorescence (IF) staining. Aneuploid blastocysts showed longer telomeres, higher telomerase reverse transcriptase (TERT) mRNA expression, and lower telomerase activity compared to euploid blastocysts. The TERT protein was found in all tested embryos via IF staining with anti-hTERT antibody, regardless of ploidy status. Moreover, telomere length or telomerase gene expression did not differ in aneuploid blastocysts between chromosomal gain or loss. Our data demonstrate that telomerase is activated and telomeres are maintained in all human blastocyst stage embryos. The robust telomerase gene expression and telomere maintenance, even in aneuploid human blastocysts, may explain why extended in vitro culture alone is insufficient to cull out aneuploid embryos during in vitro fertilization.
Collapse
Affiliation(s)
- Fang Wang
- NYU Langone Fertility Center, New York, NY 10022, USA
- Department of Obstetrics and Gynecology, NYU Grossman, School of Medicine, New York, NY 10016, USA
| | | | - Kasey Chan
- Department of Obstetrics and Gynecology, NYU Grossman, School of Medicine, New York, NY 10016, USA
| | | | | | - James A Grifo
- NYU Langone Fertility Center, New York, NY 10022, USA
| | - David L Keefe
- NYU Langone Fertility Center, New York, NY 10022, USA
- Department of Obstetrics and Gynecology, NYU Grossman, School of Medicine, New York, NY 10016, USA
| |
Collapse
|
25
|
Copley KE, Shorter J. Repetitive elements in aging and neurodegeneration. Trends Genet 2023; 39:381-400. [PMID: 36935218 PMCID: PMC10121923 DOI: 10.1016/j.tig.2023.02.008] [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: 12/14/2022] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 03/19/2023]
Abstract
Repetitive elements (REs), such as transposable elements (TEs) and satellites, comprise much of the genome. Here, we review how TEs and (peri)centromeric satellite DNA may contribute to aging and neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). Alterations in RE expression, retrotransposition, and chromatin microenvironment may shorten lifespan, elicit neurodegeneration, and impair memory and movement. REs may cause these phenotypes via DNA damage, protein sequestration, insertional mutagenesis, and inflammation. We discuss several TE families, including gypsy, HERV-K, and HERV-W, and how TEs interact with various factors, including transactive response (TAR) DNA-binding protein 43 kDa (TDP-43) and the siRNA and piwi-interacting (pi)RNA systems. Studies of TEs in neurodegeneration have focused on Drosophila and, thus, further examination in mammals is needed. We suggest that therapeutic silencing of REs could help mitigate neurodegenerative disorders.
Collapse
Affiliation(s)
- Katie E Copley
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
26
|
Muotri AR. Interchromosomal translocation in neural progenitor cells exposed to L1 retrotransposition. Genet Mol Biol 2023; 46:e20220268. [PMID: 36734369 PMCID: PMC9936793 DOI: 10.1590/1678-4685-gmb-2022-0268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/20/2022] [Indexed: 02/04/2023] Open
Abstract
LINE-1 (L1) elements are a class of transposons, comprising approximately 19% and 21% of the mouse and human genomes, respectively. L1 retrotransposons can reverse transcribe their own RNA sequence into a de novo DNA copy integrated into a new genomic location. This activity, known as retrotransposition, may induce genomic alterations, such as insertions and deletions. Interestingly, L1s can retrotranspose and generate more de novo L1 copies in brains than in other somatic tissues. Here, we describe for the first time interchromosomal translocation triggered by ectopic L1 retrotransposition in neural progenitor cells. Such an observation adds to the studies in neurological and psychiatric diseases that exhibited variation in L1 activity between diseased brains compared with controls, suggesting that L1 activity could be detrimental when de-regulated.
Collapse
Affiliation(s)
- Alysson R. Muotri
- University of California San Diego, Department of Pediatrics, La Jolla, CA, USA.,University of California San Diego, Department of Cellular & Molecular Medicine, La Jolla, CA , USA.,University of California San Diego, Center for Academic Research and Training in Anthropogeny, Kavli Institute for Brain and Mind, Archealization Center, La Jolla, CA , USA.
| |
Collapse
|
27
|
Warkocki Z. An update on post-transcriptional regulation of retrotransposons. FEBS Lett 2023; 597:380-406. [PMID: 36460901 DOI: 10.1002/1873-3468.14551] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022]
Abstract
Retrotransposons, including LINE-1, Alu, SVA, and endogenous retroviruses, are one of the major constituents of human genomic repetitive sequences. Through the process of retrotransposition, some of them occasionally insert into new genomic locations by a copy-paste mechanism involving RNA intermediates. Irrespective of de novo genomic insertions, retrotransposon expression can lead to DNA double-strand breaks and stimulate cellular innate immunity through endogenous patterns. As a result, retrotransposons are tightly regulated by multi-layered regulatory processes to prevent the dangerous effects of their expression. In recent years, significant progress was made in revealing how retrotransposon biology intertwines with general post-transcriptional RNA metabolism. Here, I summarize current knowledge on the involvement of post-transcriptional factors in the biology of retrotransposons, focusing on LINE-1. I emphasize general RNA metabolisms such as methylation of adenine (m6 A), RNA 3'-end polyadenylation and uridylation, RNA decay and translation regulation. I discuss the effects of retrotransposon RNP sequestration in cytoplasmic bodies and autophagy. Finally, I summarize how innate immunity restricts retrotransposons and how retrotransposons make use of cellular enzymes, including the DNA repair machinery, to complete their replication cycles.
Collapse
Affiliation(s)
- Zbigniew Warkocki
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| |
Collapse
|
28
|
Ahn HW, Worman ZF, Lechsinska A, Payer LM, Wang T, Malik N, Li W, Burns KH, Nath A, Levin HL. Retrotransposon insertions associated with risk of neurologic and psychiatric diseases. EMBO Rep 2023; 24:e55197. [PMID: 36367221 PMCID: PMC9827563 DOI: 10.15252/embr.202255197] [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: 04/08/2022] [Revised: 10/11/2022] [Accepted: 10/20/2022] [Indexed: 11/13/2022] Open
Abstract
Transposable elements (TEs) are active in neuronal cells raising the question whether TE insertions contribute to risk of neuropsychiatric disease. While genome-wide association studies (GWAS) serve as a tool to discover genetic loci associated with neuropsychiatric diseases, unfortunately GWAS do not directly detect structural variants such as TEs. To examine the role of TEs in psychiatric and neurologic disease, we evaluated 17,000 polymorphic TEs and find 76 are in linkage disequilibrium with disease haplotypes (P < 10-6 ) defined by GWAS. From these 76 polymorphic TEs, we identify potentially causal candidates based on having insertions in genomic regions of regulatory chromatin and on having associations with altered gene expression in brain tissues. We show that lead candidate insertions have regulatory effects on gene expression in human neural stem cells altering the activity of a minimal promoter. Taken together, we identify 10 polymorphic TE insertions that are potential candidates on par with other variants for having a causal role in neurologic and psychiatric disorders.
Collapse
Affiliation(s)
- Hyo Won Ahn
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| | - Zelia F Worman
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
- Present address:
Seven BridgesCharlestownMAUSA
| | - Arianna Lechsinska
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| | - Lindsay M Payer
- Department of PathologyJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Tongguang Wang
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Nasir Malik
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Wenxue Li
- Section of Infections of the Nervous SystemNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Kathleen H Burns
- Department of Oncologic PathologyDana‐Farber Cancer InstituteBostonMAUSA
| | - Avindra Nath
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
- Section of Infections of the Nervous SystemNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Henry L Levin
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| |
Collapse
|
29
|
Dutta B, Osato M. The RUNX Family, a Novel Multifaceted Guardian of the Genome. Cells 2023; 12:255. [PMID: 36672189 PMCID: PMC9856552 DOI: 10.3390/cells12020255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/24/2022] [Accepted: 12/30/2022] [Indexed: 01/11/2023] Open
Abstract
The DNA repair machinery exists to protect cells from daily genetic insults by orchestrating multiple intrinsic and extrinsic factors. One such factor recently identified is the Runt-related transcription factor (RUNX) family, a group of proteins that act as a master transcriptional regulator for multiple biological functions such as embryonic development, stem cell behaviors, and oncogenesis. A significant number of studies in the past decades have delineated the involvement of RUNX proteins in DNA repair. Alterations in RUNX genes cause organ failure and predisposition to cancers, as seen in patients carrying mutations in the other well-established DNA repair genes. Herein, we review the currently existing findings and provide new insights into transcriptional and non-transcriptional multifaceted regulation of DNA repair by RUNX family proteins.
Collapse
Affiliation(s)
- Bibek Dutta
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Motomi Osato
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- International Research Center for Medical Sciences, Kumamoto University, Kumamoto 860-0811, Japan
| |
Collapse
|
30
|
Garcia-Cañadas M, Sanchez-Luque FJ, Sanchez L, Rojas J, Garcia Perez JL. LINE-1 Retrotransposition Assays in Embryonic Stem Cells. Methods Mol Biol 2023; 2607:257-309. [PMID: 36449167 DOI: 10.1007/978-1-0716-2883-6_13] [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: 06/17/2023]
Abstract
The ongoing mobilization of active non-long terminal repeat (LTR) retrotransposons continues to impact the genomes of most mammals, including humans and rodents. Non-LTR retrotransposons mobilize using an intermediary RNA and a copy-and-paste mechanism termed retrotransposition. Non-LTR retrotransposons are subdivided into long and short interspersed elements (LINEs and SINEs, respectively), depending on their size and autonomy; while active class 1 LINEs (LINE-1s or L1s) encode the enzymatic machinery required to mobilize in cis, active SINEs use the enzymatic machinery of active LINE-1s to mobilize in trans. The mobilization mechanism used by LINE-1s/SINEs was exploited to develop ingenious plasmid-based retrotransposition assays in cultured cells, which typically exploit a reporter gene that can only be activated after a round of retrotransposition. Retrotransposition assays, in cis or in trans, are instrumental tools to study the biology of mammalian LINE-1s and SINEs. In fact, these and other biochemical/genetic assays were used to uncover that endogenous mammalian LINE-1s/SINEs naturally retrotranspose during early embryonic development. However, embryonic stem cells (ESCs) are typically used as a cellular model in these and other studies interrogating LINE-1/SINE expression/regulation during early embryogenesis. Thus, human and mouse ESCs represent an excellent model to understand how active retrotransposons are regulated and how their activity impacts the germline. Here, we describe robust and quantitative protocols to study human/mouse LINE-1 (in cis) and SINE (in trans) retrotransposition using (human and mice) ESCs. These protocols are designed to study the mobilization of active non-LTR retrotransposons in a cellular physiologically relevant context.
Collapse
Affiliation(s)
- Marta Garcia-Cañadas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain.
| | - Francisco J Sanchez-Luque
- Institute of Parasitology and Biomedicine "Lopez-Neyra" (IPBLN), Spanish National Research Council (CSIC), PTS Granada, Granada, Spain
| | - Laura Sanchez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Johana Rojas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Jose L Garcia Perez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain.
- MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC)/University of Edinburgh, Western General Hospital Campus, Edinburgh, UK.
| |
Collapse
|
31
|
Gerdes P, Lim SM, Ewing AD, Larcombe MR, Chan D, Sanchez-Luque FJ, Walker L, Carleton AL, James C, Knaupp AS, Carreira PE, Nefzger CM, Lister R, Richardson SR, Polo JM, Faulkner GJ. Retrotransposon instability dominates the acquired mutation landscape of mouse induced pluripotent stem cells. Nat Commun 2022; 13:7470. [PMID: 36463236 PMCID: PMC9719517 DOI: 10.1038/s41467-022-35180-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 11/22/2022] [Indexed: 12/04/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs) can in principle differentiate into any cell of the body, and have revolutionized biomedical research and regenerative medicine. Unlike their human counterparts, mouse iPSCs (miPSCs) are reported to silence transposable elements and prevent transposable element-mediated mutagenesis. Here we apply short-read or Oxford Nanopore Technologies long-read genome sequencing to 38 bulk miPSC lines reprogrammed from 10 parental cell types, and 18 single-cell miPSC clones. While single nucleotide variants and structural variants restricted to miPSCs are rare, we find 83 de novo transposable element insertions, including examples intronic to Brca1 and Dmd. LINE-1 retrotransposons are profoundly hypomethylated in miPSCs, beyond other transposable elements and the genome overall, and harbor alternative protein-coding gene promoters. We show that treatment with the LINE-1 inhibitor lamivudine does not hinder reprogramming and efficiently blocks endogenous retrotransposition, as detected by long-read genome sequencing. These experiments reveal the complete spectrum and potential significance of mutations acquired by miPSCs.
Collapse
Affiliation(s)
- Patricia Gerdes
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Sue Mei Lim
- grid.1002.30000 0004 1936 7857Department of Anatomy & Developmental Biology, Monash University, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC 3800 Australia
| | - Adam D. Ewing
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Michael R. Larcombe
- grid.1002.30000 0004 1936 7857Department of Anatomy & Developmental Biology, Monash University, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC 3800 Australia
| | - Dorothy Chan
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Francisco J. Sanchez-Luque
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia ,grid.418805.00000 0004 0500 8423GENYO. Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS, Granada, 18016 Spain
| | - Lucinda Walker
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Alexander L. Carleton
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Cini James
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Anja S. Knaupp
- grid.1002.30000 0004 1936 7857Department of Anatomy & Developmental Biology, Monash University, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC 3800 Australia
| | - Patricia E. Carreira
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Christian M. Nefzger
- grid.1002.30000 0004 1936 7857Department of Anatomy & Developmental Biology, Monash University, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC 3800 Australia
| | - Ryan Lister
- grid.1012.20000 0004 1936 7910Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Perth, WA 6009 Australia ,grid.431595.f0000 0004 0469 0045Harry Perkins Institute of Medical Research, Perth, WA 6009 Australia
| | - Sandra R. Richardson
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
| | - Jose M. Polo
- grid.1002.30000 0004 1936 7857Department of Anatomy & Developmental Biology, Monash University, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC 3800 Australia ,grid.1010.00000 0004 1936 7304Adelaide Centre for Epigenetics and The South Australian Immunogenomics Cancer Institute, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Geoffrey J. Faulkner
- grid.1003.20000 0000 9320 7537Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia ,grid.1003.20000 0000 9320 7537Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072 Australia
| |
Collapse
|
32
|
Wyrwoll MJ, Gaasbeek CM, Golubickaite I, Stakaitis R, Oud MS, Nagirnaja L, Dion C, Sindi EB, Leitch HG, Jayasena CN, Sironen A, Dicke AK, Rotte N, Stallmeyer B, Kliesch S, Grangeiro CHP, Araujo TF, Lasko P, D'Hauwers K, Smits RM, Ramos L, Xavier MJ, Conrad DF, Almstrup K, Veltman JA, Tüttelmann F, van der Heijden GW. The piRNA-pathway factor FKBP6 is essential for spermatogenesis but dispensable for control of meiotic LINE-1 expression in humans. Am J Hum Genet 2022; 109:1850-1866. [PMID: 36150389 PMCID: PMC9606565 DOI: 10.1016/j.ajhg.2022.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 09/01/2022] [Indexed: 01/25/2023] Open
Abstract
Infertility affects around 7% of the male population and can be due to severe spermatogenic failure (SPGF), resulting in no or very few sperm in the ejaculate. We initially identified a homozygous frameshift variant in FKBP6 in a man with extreme oligozoospermia. Subsequently, we screened a total of 2,699 men with SPGF and detected rare bi-allelic loss-of-function variants in FKBP6 in five additional persons. All six individuals had no or extremely few sperm in the ejaculate, which were not suitable for medically assisted reproduction. Evaluation of testicular tissue revealed an arrest at the stage of round spermatids. Lack of FKBP6 expression in the testis was confirmed by RT-qPCR and immunofluorescence staining. In mice, Fkbp6 is essential for spermatogenesis and has been described as being involved in piRNA biogenesis and formation of the synaptonemal complex (SC). We did not detect FKBP6 as part of the SC in normal human spermatocytes, but small RNA sequencing revealed that loss of FKBP6 severely impacted piRNA levels, supporting a role for FKBP6 in piRNA biogenesis in humans. In contrast to findings in piRNA-pathway mouse models, we did not detect an increase in LINE-1 expression in men with pathogenic FKBP6 variants. Based on our findings, FKBP6 reaches a "strong" level of evidence for being associated with male infertility according to the ClinGen criteria, making it directly applicable for clinical diagnostics. This will improve patient care by providing a causal diagnosis and will help to predict chances for successful surgical sperm retrieval.
Collapse
Affiliation(s)
- Margot J Wyrwoll
- Institute of Reproductive Genetics, University of Münster, Münster, Germany
| | - Channah M Gaasbeek
- Department of Human Genetics, Radboudumc, Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, the Netherlands; Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ieva Golubickaite
- Division of Genetics, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA; Department of Growth and Reproduction, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Genetics and Molecular Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Rytis Stakaitis
- Division of Genetics, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA; Department of Growth and Reproduction, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Laboratory of Molecular Neurooncology, Neuroscience Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Manon S Oud
- Department of Human Genetics, Radboudumc, Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, the Netherlands
| | - Liina Nagirnaja
- Division of Genetics, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Camille Dion
- MRC London Institute of Medical Sciences, London, UK; Institute of Clinical Sciences, Imperial College London, London, UK
| | - Emad B Sindi
- Section of Investigative Medicine, Imperial College London, London, UK
| | - Harry G Leitch
- MRC London Institute of Medical Sciences, London, UK; Institute of Clinical Sciences, Imperial College London, London, UK; Centre for Paediatrics and Child Health, Faculty of Medicine, Imperial College London, London, UK
| | - Channa N Jayasena
- Section of Investigative Medicine, Imperial College London, London, UK
| | - Anu Sironen
- Natural Resources Institute Finland, Production Systems, Jokioinen, Finland; Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Ann-Kristin Dicke
- Institute of Reproductive Genetics, University of Münster, Münster, Germany
| | - Nadja Rotte
- Institute of Reproductive Genetics, University of Münster, Münster, Germany
| | - Birgit Stallmeyer
- Institute of Reproductive Genetics, University of Münster, Münster, Germany
| | - Sabine Kliesch
- Centre of Reproductive Medicine and Andrology, Department of Clinical and Surgical Andrology, University Hospital of Münster, Münster, Germany
| | | | - Thaís F Araujo
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Paul Lasko
- Department of Human Genetics, Radboudumc, Nijmegen, the Netherlands; Department of Biology, McGill University, Montréal, QC, Canada
| | | | - Roos M Smits
- Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Liliana Ramos
- Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Miguel J Xavier
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Don F Conrad
- Division of Genetics, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Kristian Almstrup
- Department of Growth and Reproduction, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Joris A Veltman
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Frank Tüttelmann
- Institute of Reproductive Genetics, University of Münster, Münster, Germany
| | | |
Collapse
|
33
|
Li Y, Yang J, Shen S, Wang W, Liu N, Guo H, Wei W. SARS-CoV-2-encoded inhibitors of human LINE-1 retrotransposition. J Med Virol 2022; 95:e28135. [PMID: 36085352 PMCID: PMC9538743 DOI: 10.1002/jmv.28135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 01/11/2023]
Abstract
The ongoing pandemic of severe acute respiratory coronavirus 2 (SARS-CoV-2) is causing a devastating impact on public health worldwide. However, details concerning the profound impact of SARS-CoV-2 on host cells remain elusive. Here, we investigated the effects of SARS-CoV-2-encoded viral proteins on the intracellular activity of long interspersed element 1 (L1) retrotransposons using well-established reporter systems. Several nonstructural or accessory proteins (Nsps) of SARS-CoV-2 (i.e., Nsp1, Nsp3, Nsp5, and Nsp14) significantly suppress human L1 mobility, and these viral L1 inhibitors generate a complex network that modulates L1 transposition. Specifically, Nsp1 and Nsp14 inhibit the intracellular accumulation of L1 open reading frame proteins (ORF1p), whereas Nsp3, Nsp5, and Nsp14 repress the reverse transcriptase activity of L1 ORF2p. Given recent findings concerning the roles of L1 in antiviral immune activation and host genome instability, the anti-L1 activities mediated by SARS-CoV-2-encoded inhibitors suggest that SARS-CoV-2 employs different strategies to optimize the host genetic environment.
Collapse
Affiliation(s)
- Yan Li
- Institute of Virology and AIDS Research, First HospitalJilin UniversityChangchunJilinChina
| | - Jiaxin Yang
- Institute of Virology and AIDS Research, First HospitalJilin UniversityChangchunJilinChina
| | - Siyu Shen
- Institute of Virology and AIDS Research, First HospitalJilin UniversityChangchunJilinChina
| | - Wei Wang
- Institute of Virology and AIDS Research, First HospitalJilin UniversityChangchunJilinChina
| | - Nian Liu
- School of Life SciencesTsinghua UniversityBeijingChina
| | - Haoran Guo
- Institute of Virology and AIDS Research, First HospitalJilin UniversityChangchunJilinChina,Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First HospitalJilin UniversityChangchunJilinChina
| | - Wei Wei
- Institute of Virology and AIDS Research, First HospitalJilin UniversityChangchunJilinChina,Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First HospitalJilin UniversityChangchunJilinChina
| |
Collapse
|
34
|
Billon V, Sanchez-Luque FJ, Rasmussen J, Bodea GO, Gerhardt DJ, Gerdes P, Cheetham SW, Schauer SN, Ajjikuttira P, Meyer TJ, Layman CE, Nevonen KA, Jansz N, Garcia-Perez JL, Richardson SR, Ewing AD, Carbone L, Faulkner GJ. Somatic retrotransposition in the developing rhesus macaque brain. Genome Res 2022; 32:1298-1314. [PMID: 35728967 PMCID: PMC9341517 DOI: 10.1101/gr.276451.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022]
Abstract
The retrotransposon LINE-1 (L1) is central to the recent evolutionary history of the human genome and continues to drive genetic diversity and germline pathogenesis. However, the spatiotemporal extent and biological significance of somatic L1 activity are poorly defined and are virtually unexplored in other primates. From a single L1 lineage active at the divergence of apes and Old World monkeys, successive L1 subfamilies have emerged in each descendant primate germline. As revealed by case studies, the presently active human L1 subfamily can also mobilize during embryonic and brain development in vivo. It is unknown whether nonhuman primate L1s can similarly generate somatic insertions in the brain. Here we applied approximately 40× single-cell whole-genome sequencing (scWGS), as well as retrotransposon capture sequencing (RC-seq), to 20 hippocampal neurons from two rhesus macaques (Macaca mulatta). In one animal, we detected and PCR-validated a somatic L1 insertion that generated target site duplications, carried a short 5' transduction, and was present in ∼7% of hippocampal neurons but absent from cerebellum and nonbrain tissues. The corresponding donor L1 allele was exceptionally mobile in vitro and was embedded in PRDM4, a gene expressed throughout development and in neural stem cells. Nanopore long-read methylome and RNA-seq transcriptome analyses indicated young retrotransposon subfamily activation in the early embryo, followed by repression in adult tissues. These data highlight endogenous macaque L1 retrotransposition potential, provide prototypical evidence of L1-mediated somatic mosaicism in a nonhuman primate, and allude to L1 mobility in the brain over the past 30 million years of human evolution.
Collapse
Affiliation(s)
- Victor Billon
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
- Biology Department, École Normale Supérieure Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Francisco J Sanchez-Luque
- GENYO. Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
- Institute of Parasitology and Biomedicine "Lopez-Neyra"-Spanish National Research Council, PTS Granada 18016, Spain
| | - Jay Rasmussen
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
| | - Gabriela O Bodea
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Daniel J Gerhardt
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Patricia Gerdes
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Seth W Cheetham
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Stephanie N Schauer
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Prabha Ajjikuttira
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
| | - Thomas J Meyer
- Division of Genetics, Oregon National Primate Research Center, Beaverton, Oregon 97006, USA
| | - Cora E Layman
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Kimberly A Nevonen
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Natasha Jansz
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Jose L Garcia-Perez
- GENYO. Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
| | - Sandra R Richardson
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Adam D Ewing
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Lucia Carbone
- Division of Genetics, Oregon National Primate Research Center, Beaverton, Oregon 97006, USA
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Geoffrey J Faulkner
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| |
Collapse
|
35
|
Jahangir M, Li L, Zhou JS, Lang B, Wang XP. L1 Retrotransposons: A Potential Endogenous Regulator for Schizophrenia. Front Genet 2022; 13:878508. [PMID: 35832186 PMCID: PMC9271560 DOI: 10.3389/fgene.2022.878508] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
The long interspersed nuclear elements 1 (LINE-1/L1s) are the only active autonomous retrotransposons found in humans which can integrate anywhere in the human genome. They can expand the genome and thus bring good or bad effects to the host cells which really depends on their integration site and associated polymorphism. LINE-1 retrotransposition has been found participating in various neurological disorders such as autism spectrum disorder, Alzheimer’s disease, major depression disorder, post-traumatic stress disorder and schizophrenia. Despite the recent progress, the roles and pathological mechanism of LINE-1 retrotransposition in schizophrenia and its heritable risks, particularly, contribution to “missing heritability” are yet to be determined. Therefore, this review focuses on the potentially etiological roles of L1s in the development of schizophrenia, possible therapeutic choices and unaddressed questions in order to shed lights on the future research.
Collapse
Affiliation(s)
| | | | | | - Bing Lang
- *Correspondence: Bing Lang, ; Xiao-Ping Wang,
| | | |
Collapse
|
36
|
Jacquier A, Roubille S, Lomonte P, Schaeffer L. Microrchidia CW-Type Zinc Finger 2, a Chromatin Modifier in a Spectrum of Peripheral Neuropathies. Front Cell Neurosci 2022; 16:896854. [PMID: 35722617 PMCID: PMC9203694 DOI: 10.3389/fncel.2022.896854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/11/2022] [Indexed: 12/12/2022] Open
Abstract
Microrchidia CW-type zinc finger 2 (MORC2) gene encodes a protein expressed in all tissues and enriched in the brain. MORC2 protein is composed of a catalytic ATPase domain, three coil-coiled domains allowing dimerization or protein complex interaction, a zinc-finger CW domain allowing DNA interaction, and a CHROMO-like (CHRromatin Organization Modifier) domain. Recently, de novo or dominantly inherited heterozygous mutations have been associated with a spectrum of disorders affecting the peripheral nervous system such as the Charcot-Marie-Tooth disease, spinal muscular atrophy-like phenotype disorder, or a neurodevelopmental syndrome associated with developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy (DIGFAN). In this review, we detail the various mutations of MORC2 and their consequences on clinical manifestations. Possible genotype-phenotype correlations as well as intra and inter-family variability are discussed. MORC2 molecular functions such as transcriptional modulation, DNA damage repair, and lipid metabolism are then reviewed. We further discuss the impact of MORC2 mutations on the epigenetic landscape in the neuromuscular system and hypothesize probable pathophysiological mechanisms underlying the phenotypic variability observed.
Collapse
Affiliation(s)
- Arnaud Jacquier
- INMG-Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, Lyon, France
- Hospices Civils de Lyon, Groupement Est, Bron, France
| | - Simon Roubille
- INMG-Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, Lyon, France
| | - Patrick Lomonte
- INMG-Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, Lyon, France
| | - Laurent Schaeffer
- INMG-Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, Lyon, France
- Hospices Civils de Lyon, Groupement Est, Bron, France
| |
Collapse
|
37
|
Chesnokova E, Beletskiy A, Kolosov P. The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:5847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
Collapse
Affiliation(s)
- Ekaterina Chesnokova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, 117485 Moscow, Russia; (A.B.); (P.K.)
| | | | | |
Collapse
|
38
|
A retrotransposon storm marks clinical phenoconversion to late-onset Alzheimer's disease. GeroScience 2022; 44:1525-1550. [PMID: 35585302 PMCID: PMC9213607 DOI: 10.1007/s11357-022-00580-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/26/2022] [Indexed: 12/03/2022] Open
Abstract
Recent reports have suggested that the reactivation of otherwise transcriptionally silent transposable elements (TEs) might induce brain degeneration, either by dysregulating the expression of genes and pathways implicated in cognitive decline and dementia or through the induction of immune-mediated neuroinflammation resulting in the elimination of neural and glial cells. In the work we present here, we test the hypothesis that differentially expressed TEs in blood could be used as biomarkers of cognitive decline and development of AD. To this aim, we used a sample of aging subjects (age > 70) that developed late-onset Alzheimer’s disease (LOAD) over a relatively short period of time (12–48 months), for which blood was available before and after their phenoconversion, and a group of cognitive stable subjects as controls. We applied our developed and validated customized pipeline that allows the identification, characterization, and quantification of the differentially expressed (DE) TEs before and after the onset of manifest LOAD, through analyses of RNA-Seq data. We compared the level of DE TEs within more than 600,000 TE-mapping RNA transcripts from 25 individuals, whose specimens we obtained before and after their phenotypic conversion (phenoconversion) to LOAD, and discovered that 1790 TE transcripts showed significant expression differences between these two timepoints (logFC ± 1.5, logCMP > 5.3, nominal p value < 0.01). These DE transcripts mapped both over- and under-expressed TE elements. Occurring before the clinical phenoconversion, this TE storm features significant increases in DE transcripts of LINEs, LTRs, and SVAs, while those for SINEs are significantly depleted. These dysregulations end with signs of manifest LOAD. This set of highly DE transcripts generates a TE transcriptional profile that accurately discriminates the before and after phenoconversion states of these subjects. Our findings suggest that a storm of DE TEs occurs before phenoconversion from normal cognition to manifest LOAD in risk individuals compared to controls, and may provide useful blood-based biomarkers for heralding such a clinical transition, also suggesting that TEs can indeed participate in the complex process of neurodegeneration.
Collapse
|
39
|
Takahashi F, Zhang C, Hohjoh H, Raveney B, Yamamura T, Hayashi N, Oki S. Immune-mediated neurodegenerative trait provoked by multimodal derepression of long-interspersed nuclear element-1. iScience 2022; 25:104278. [PMID: 35573205 PMCID: PMC9097630 DOI: 10.1016/j.isci.2022.104278] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/25/2022] [Accepted: 04/18/2022] [Indexed: 11/25/2022] Open
Abstract
Neurodegeneration is a process involving both cell autonomous and non-cell autonomous neuron loss, followed by a collapse of neural networks, but its pathogenesis is poorly understood. We have previously demonstrated that Eomes-positive helper T (Eomes + Th) cells recognizing LINE-1(L1)-derived prototypic antigen ORF1 mediate neurotoxicity associated with the neurodegenerative pathology of experimental autoimmune encephalomyelitis (EAE). Here, we show that Eomes + Th cells accumulate in the CNS of mouse models of authentic neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and Alzheimer’s disease (AD), and secrete the neurotoxic granzyme B after encounter with ORF1 antigen. Multimodal derepression of neuronal L1 transcription is observed in EAE and ALS/AD models during neurodegeneration in active and cell cycle-mediated manner, respectively. These data suggest that the adventitious concurrence of immune-mediated neurodegenerative traits by Eomes + Th cells and ectopic expression of L1-derived antigen(s) in the inflamed CNS may materialize a communal and previously unappreciated pathogenesis of neurodegeneration. Eomes + Th cells accumulate in the CNS with undergoing neurodegeneration in common Multimodal L1 derepression is emerged in neuron cells under neurodegeneration Eomes + Th cells recognize L1-ORF1 antigen to exert neurotoxicity via granzyme B Immune-mediated neurotoxicity may embody a novel pathogenesis of neurodegeneration
Collapse
Affiliation(s)
- Fumio Takahashi
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Chenyang Zhang
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Hirohiko Hohjoh
- Department of Molecular Pharmacology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Ben Raveney
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Takashi Yamamura
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Nobuhiro Hayashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Shinji Oki
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
- Corresponding author
| |
Collapse
|
40
|
Domazet-Lošo T. mRNA Vaccines: Why Is the Biology of Retroposition Ignored? Genes (Basel) 2022; 13:719. [PMID: 35627104 PMCID: PMC9141755 DOI: 10.3390/genes13050719] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 02/07/2023] Open
Abstract
The major advantage of mRNA vaccines over more conventional approaches is their potential for rapid development and large-scale deployment in pandemic situations. In the current COVID-19 crisis, two mRNA COVID-19 vaccines have been conditionally approved and broadly applied, while others are still in clinical trials. However, there is no previous experience with the use of mRNA vaccines on a large scale in the general population. This warrants a careful evaluation of mRNA vaccine safety properties by considering all available knowledge about mRNA molecular biology and evolution. Here, I discuss the pervasive claim that mRNA-based vaccines cannot alter genomes. Surprisingly, this notion is widely stated in the mRNA vaccine literature but never supported by referencing any primary scientific papers that would specifically address this question. This discrepancy becomes even more puzzling if one considers previous work on the molecular and evolutionary aspects of retroposition in murine and human populations that clearly documents the frequent integration of mRNA molecules into genomes, including clinical contexts. By performing basic comparisons, I show that the sequence features of mRNA vaccines meet all known requirements for retroposition using L1 elements-the most abundant autonomously active retrotransposons in the human genome. In fact, many factors associated with mRNA vaccines increase the possibility of their L1-mediated retroposition. I conclude that is unfounded to a priori assume that mRNA-based therapeutics do not impact genomes and that the route to genome integration of vaccine mRNAs via endogenous L1 retroelements is easily conceivable. This implies that we urgently need experimental studies that would rigorously test for the potential retroposition of vaccine mRNAs. At present, the insertional mutagenesis safety of mRNA-based vaccines should be considered unresolved.
Collapse
Affiliation(s)
- Tomislav Domazet-Lošo
- Laboratory of Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička Cesta 54, HR-10000 Zagreb, Croatia;
- School of Medicine, Catholic University of Croatia, Ilica 242, HR-10000 Zagreb, Croatia
| |
Collapse
|
41
|
Intracellular Reverse Transcription of Pfizer BioNTech COVID-19 mRNA Vaccine BNT162b2 In Vitro in Human Liver Cell Line. Curr Issues Mol Biol 2022; 44:1115-1126. [PMID: 35723296 PMCID: PMC8946961 DOI: 10.3390/cimb44030073] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/19/2022] [Accepted: 02/23/2022] [Indexed: 12/25/2022] Open
Abstract
Preclinical studies of COVID-19 mRNA vaccine BNT162b2, developed by Pfizer and BioNTech, showed reversible hepatic effects in animals that received the BNT162b2 injection. Furthermore, a recent study showed that SARS-CoV-2 RNA can be reverse-transcribed and integrated into the genome of human cells. In this study, we investigated the effect of BNT162b2 on the human liver cell line Huh7 in vitro. Huh7 cells were exposed to BNT162b2, and quantitative PCR was performed on RNA extracted from the cells. We detected high levels of BNT162b2 in Huh7 cells and changes in gene expression of long interspersed nuclear element-1 (LINE-1), which is an endogenous reverse transcriptase. Immunohistochemistry using antibody binding to LINE-1 open reading frame-1 RNA-binding protein (ORFp1) on Huh7 cells treated with BNT162b2 indicated increased nucleus distribution of LINE-1. PCR on genomic DNA of Huh7 cells exposed to BNT162b2 amplified the DNA sequence unique to BNT162b2. Our results indicate a fast up-take of BNT162b2 into human liver cell line Huh7, leading to changes in LINE-1 expression and distribution. We also show that BNT162b2 mRNA is reverse transcribed intracellularly into DNA in as fast as 6 h upon BNT162b2 exposure.
Collapse
|
42
|
Peze-Heidsieck E, Bonnifet T, Znaidi R, Ravel-Godreuil C, Massiani-Beaudoin O, Joshi RL, Fuchs J. Retrotransposons as a Source of DNA Damage in Neurodegeneration. Front Aging Neurosci 2022; 13:786897. [PMID: 35058771 PMCID: PMC8764243 DOI: 10.3389/fnagi.2021.786897] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/30/2021] [Indexed: 01/09/2023] Open
Abstract
The etiology of aging-associated neurodegenerative diseases (NDs), such as Parkinson's disease (PD) and Alzheimer's disease (AD), still remains elusive and no curative treatment is available. Age is the major risk factor for PD and AD, but the molecular link between aging and neurodegeneration is not fully understood. Aging is defined by several hallmarks, some of which partially overlap with pathways implicated in NDs. Recent evidence suggests that aging-associated epigenetic alterations can lead to the derepression of the LINE-1 (Long Interspersed Element-1) family of transposable elements (TEs) and that this derepression might have important implications in the pathogenesis of NDs. Almost half of the human DNA is composed of repetitive sequences derived from TEs and TE mobility participated in shaping the mammalian genomes during evolution. Although most TEs are mutated and no longer mobile, more than 100 LINE-1 elements have retained their full coding potential in humans and are thus retrotransposition competent. Uncontrolled activation of TEs has now been reported in various models of neurodegeneration and in diseased human brain tissues. We will discuss in this review the potential contribution of LINE-1 elements in inducing DNA damage and genomic instability, which are emerging pathological features in NDs. TEs might represent an important molecular link between aging and neurodegeneration, and a potential target for urgently needed novel therapeutic disease-modifying interventions.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Julia Fuchs
- Center for Interdisciplinary Research in Biology (CIRB), CNRS, INSERM, Collège de France, Université PSL, Paris, France
| |
Collapse
|
43
|
Akhlaghpour H. An RNA-Based Theory of Natural Universal Computation. J Theor Biol 2021; 537:110984. [PMID: 34979104 DOI: 10.1016/j.jtbi.2021.110984] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 09/30/2021] [Accepted: 12/07/2021] [Indexed: 12/15/2022]
Abstract
Life is confronted with computation problems in a variety of domains including animal behavior, single-cell behavior, and embryonic development. Yet we currently do not know of a naturally existing biological system that is capable of universal computation, i.e., Turing-equivalent in scope. Generic finite-dimensional dynamical systems (which encompass most models of neural networks, intracellular signaling cascades, and gene regulatory networks) fall short of universal computation, but are assumed to be capable of explaining cognition and development. I present a class of models that bridge two concepts from distant fields: combinatory logic (or, equivalently, lambda calculus) and RNA molecular biology. A set of basic RNA editing rules can make it possible to compute any computable function with identical algorithmic complexity to that of Turing machines. The models do not assume extraordinarily complex molecular machinery or any processes that radically differ from what we already know to occur in cells. Distinct independent enzymes can mediate each of the rules and RNA molecules solve the problem of parenthesis matching through their secondary structure. In the most plausible of these models all of the editing rules can be implemented with merely cleavage and ligation operations at fixed positions relative to predefined motifs. This demonstrates that universal computation is well within the reach of molecular biology. It is therefore reasonable to assume that life has evolved - or possibly began with - a universal computer that yet remains to be discovered. The variety of seemingly unrelated computational problems across many scales can potentially be solved using the same RNA-based computation system. Experimental validation of this theory may immensely impact our understanding of memory, cognition, development, disease, evolution, and the early stages of life.
Collapse
Affiliation(s)
- Hessameddin Akhlaghpour
- Laboratory of Integrative Brain Function, The Rockefeller University, New York, NY, 10065, USA
| |
Collapse
|
44
|
Savino A, Nichols CD. Lysergic acid diethylamide induces increased signalling entropy in rats' prefrontal cortex. J Neurochem 2021; 162:9-23. [PMID: 34729786 PMCID: PMC9298798 DOI: 10.1111/jnc.15534] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 12/11/2022]
Abstract
Psychedelic drugs are gaining attention from the scientific community as potential new compounds for the treatment of psychiatric diseases such as mood and substance use disorders. The 5‐HT2A receptor has been identified as the main molecular target, and early studies pointed to an effect on the expression of neuroplasticity genes. Analysing RNA‐seq data from the prefrontal cortex of rats chronically treated with lysergic acid diethylamide (LSD), we describe the psychedelic‐induced rewiring of gene co‐expression networks, which become less centralised but more complex, with an overall increase in signalling entropy typical of highly plastic systems. Intriguingly, signalling entropy mirrors, at the molecular level, the increased brain entropy reported through neuroimaging studies in human, suggesting the underlying mechanisms of higher‐order phenomena. Moreover, from the analysis of network topology, we identify potential transcriptional regulators and propose the involvement of different cell types in psychedelics’ activity.
Collapse
Affiliation(s)
- Aurora Savino
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, Italy
| | - Charles D Nichols
- Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| |
Collapse
|
45
|
Ravel-Godreuil C, Znaidi R, Bonnifet T, Joshi RL, Fuchs J. Transposable elements as new players in neurodegenerative diseases. FEBS Lett 2021; 595:2733-2755. [PMID: 34626428 DOI: 10.1002/1873-3468.14205] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/23/2021] [Accepted: 10/03/2021] [Indexed: 01/02/2023]
Abstract
Neurodegenerative diseases (NDs), including the most prevalent Alzheimer's disease and Parkinson disease, share common pathological features. Despite decades of gene-centric approaches, the molecular mechanisms underlying these diseases remain widely elusive. In recent years, transposable elements (TEs), long considered 'junk' DNA, have gained growing interest as pathogenic players in NDs. Age is the major risk factor for most NDs, and several repressive mechanisms of TEs, such as heterochromatinization, fail with age. Indeed, heterochromatin relaxation leading to TE derepression has been reported in various models of neurodegeneration and NDs. There is also evidence that certain pathogenic proteins involved in NDs (e.g., tau, TDP-43) may control the expression of TEs. The deleterious consequences of TE activation are not well known but they could include DNA damage and genomic instability, altered host gene expression, and/or neuroinflammation, which are common hallmarks of neurodegeneration and aging. TEs might thus represent an overlooked pathogenic culprit for both brain aging and neurodegeneration. Certain pathological effects of TEs might be prevented by inhibiting their activity, pointing to TEs as novel targets for neuroprotection.
Collapse
Affiliation(s)
- Camille Ravel-Godreuil
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rania Znaidi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Tom Bonnifet
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rajiv L Joshi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Julia Fuchs
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| |
Collapse
|
46
|
Factors Regulating the Activity of LINE1 Retrotransposons. Genes (Basel) 2021; 12:genes12101562. [PMID: 34680956 PMCID: PMC8535693 DOI: 10.3390/genes12101562] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [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.
Collapse
|
47
|
Costantino I, Nicodemus J, Chun J. Genomic Mosaicism Formed by Somatic Variation in the Aging and Diseased Brain. Genes (Basel) 2021; 12:1071. [PMID: 34356087 PMCID: PMC8305509 DOI: 10.3390/genes12071071] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Over the past 20 years, analyses of single brain cell genomes have revealed that the brain is composed of cells with myriad distinct genomes: the brain is a genomic mosaic, generated by a host of DNA sequence-altering processes that occur somatically and do not affect the germline. As such, these sequence changes are not heritable. Some processes appear to occur during neurogenesis, when cells are mitotic, whereas others may also function in post-mitotic cells. Here, we review multiple forms of DNA sequence alterations that have now been documented: aneuploidies and aneusomies, smaller copy number variations (CNVs), somatic repeat expansions, retrotransposons, genomic cDNAs (gencDNAs) associated with somatic gene recombination (SGR), and single nucleotide variations (SNVs). A catch-all term of DNA content variation (DCV) has also been used to describe the overall phenomenon, which can include multiple forms within a single cell's genome. A requisite step in the analyses of genomic mosaicism is ongoing technology development, which is also discussed. Genomic mosaicism alters one of the most stable biological molecules, DNA, which may have many repercussions, ranging from normal functions including effects of aging, to creating dysfunction that occurs in neurodegenerative and other brain diseases, most of which show sporadic presentation, unlinked to causal, heritable genes.
Collapse
Affiliation(s)
- Isabel Costantino
- Translational Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; (I.C.); (J.N.)
- Neurosciences Graduate Program, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Juliet Nicodemus
- Translational Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; (I.C.); (J.N.)
- Neurosciences Graduate Program, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Jerold Chun
- Translational Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; (I.C.); (J.N.)
| |
Collapse
|
48
|
Siudeja K, van den Beek M, Riddiford N, Boumard B, Wurmser A, Stefanutti M, Lameiras S, Bardin AJ. Unraveling the features of somatic transposition in the Drosophila intestine. EMBO J 2021; 40:e106388. [PMID: 33634906 PMCID: PMC8090852 DOI: 10.15252/embj.2020106388] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) play a significant role in evolution, contributing to genetic variation. However, TE mobilization in somatic cells is not well understood. Here, we address the prevalence of transposition in a somatic tissue, exploiting the Drosophila midgut as a model. Using whole-genome sequencing of in vivo clonally expanded gut tissue, we have mapped hundreds of high-confidence somatic TE integration sites genome-wide. We show that somatic retrotransposon insertions are associated with inactivation of the tumor suppressor Notch, likely contributing to neoplasia formation. Moreover, applying Oxford Nanopore long-read sequencing technology we provide evidence for tissue-specific differences in retrotransposition. Comparing somatic TE insertional activity with transcriptomic and small RNA sequencing data, we demonstrate that transposon mobility cannot be simply predicted by whole tissue TE expression levels or by small RNA pathway activity. Finally, we reveal that somatic TE insertions in the adult fly intestine are enriched in genic regions and in transcriptionally active chromatin. Together, our findings provide clear evidence of ongoing somatic transposition in Drosophila and delineate previously unknown features underlying somatic TE mobility in vivo.
Collapse
Affiliation(s)
- Katarzyna Siudeja
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Marius van den Beek
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Nick Riddiford
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Benjamin Boumard
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Annabelle Wurmser
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Marine Stefanutti
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Sonia Lameiras
- ICGex Next‐Generation Sequencing PlatformInstitut CuriePSL Research UniversityParisFrance
| | - Allison J Bardin
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| |
Collapse
|
49
|
Ross SE, Hesselson D, Bogdanovic O. Developmental Accumulation of Gene Body and Transposon Non-CpG Methylation in the Zebrafish Brain. Front Cell Dev Biol 2021; 9:643603. [PMID: 33748137 PMCID: PMC7978034 DOI: 10.3389/fcell.2021.643603] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/08/2021] [Indexed: 12/13/2022] Open
Abstract
DNA methylation predominantly occurs at CG dinucleotides in vertebrate genomes; however, non-CG methylation (mCH) is also detectable in vertebrate tissues, most notably in the nervous system. In mammals it is well established that mCH is targeted to CAC trinucleotides by DNMT3A during nervous system development where it is enriched in gene bodies and associated with transcriptional repression. Nevertheless, the conservation of developmental mCH accumulation and its deposition by DNMT3A is largely unexplored and has yet to be functionally demonstrated in other vertebrates. In this study, by analyzing DNA methylomes and transcriptomes of zebrafish brains, we identified enrichment of mCH at CAC trinucleotides (mCAC) at defined transposon motifs as well as in developmentally downregulated genes associated with developmental and neural functions. We further generated and analyzed DNA methylomes and transcriptomes of developing zebrafish larvae and demonstrated that, like in mammals, mCH accumulates during post-embryonic brain development. Finally, by employing CRISPR/Cas9 technology, we unraveled a conserved role for Dnmt3a enzymes in developmental mCAC deposition. Overall, this work demonstrates the evolutionary conservation of developmental mCH dynamics and highlights the potential of zebrafish as a model to study mCH regulation and function during normal and perturbed development.
Collapse
Affiliation(s)
- Samuel E Ross
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.,Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Daniel Hesselson
- Centenary Institute, The University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Ozren Bogdanovic
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
50
|
Ahmadi A, De Toma I, Vilor-Tejedor N, Eftekhariyan Ghamsari MR, Sadeghi I. Transposable elements in brain health and disease. Ageing Res Rev 2020; 64:101153. [PMID: 32977057 DOI: 10.1016/j.arr.2020.101153] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 07/22/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022]
Abstract
Transposable elements (TEs) occupy a large fraction of the human genome but only a small proportion of these elements are still active today. Recent works have suggested that TEs are expressed and active in the brain, challenging the dogma that neuronal genomes are static and revealing that they are susceptible to somatic genomic alterations. These new findings have major implications for understanding the neuroplasticity of the brain, which could hypothetically have a role in behavior and cognition, and contribute to vulnerability to disease. As active TEs could induce genetic diversity and mutagenesis, their influences on human brain development and diseases are of great interest. In this review, we will focus on the active TEs in the human genome and discuss in detail their impacts on human brain development. Furthermore, the association between TEs and brain-related diseases is discussed.
Collapse
|