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Kojima S. Investigating mobile element variations by statistical genetics. Hum Genome Var 2024; 11:23. [PMID: 38816353 PMCID: PMC11140006 DOI: 10.1038/s41439-024-00280-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 06/01/2024] Open
Abstract
The integration of structural variations (SVs) in statistical genetics provides an opportunity to understand the genetic factors influencing complex human traits and disease. Recent advances in long-read technology and variant calling methods for short reads have improved the accurate discovery and genotyping of SVs, enabling their use in expression quantitative trait loci (eQTL) analysis and genome-wide association studies (GWAS). Mobile elements are DNA sequences that insert themselves into various genome locations. Insertional polymorphisms of mobile elements between humans, called mobile element variations (MEVs), contribute to approximately 25% of human SVs. We recently developed a variant caller that can accurately identify and genotype MEVs from biobank-scale short-read whole-genome sequencing (WGS) datasets and integrate them into statistical genetics. The use of MEVs in eQTL analysis and GWAS has a minimal impact on the discovery of genome loci associated with gene expression and disease; most disease-associated haplotypes can be identified by single nucleotide variations (SNVs). On the other hand, it helps make hypotheses about causal variants or effector variants. Focusing on MEVs, we identified multiple MEVs that contribute to differential gene expression and one of them is a potential cause of skin disease, emphasizing the importance of the integration of MEVs in medical genetics. Here, I will provide an overview of MEVs, MEV calling from WGS, and the integration of MEVs in statistical genetics. Finally, I will discuss the unanswered questions about MEVs, such as rare variants.
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Affiliation(s)
- Shohei Kojima
- Genome Immunobiology RIKEN Hakubi Research Team, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan.
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Kulski JK, Suzuki S, Shiina T, Pfaff AL, Kõks S. Regulatory SVA retrotransposons and classical HLA genotyped-transcripts associated with Parkinson's disease. Front Immunol 2024; 15:1349030. [PMID: 38590523 PMCID: PMC10999589 DOI: 10.3389/fimmu.2024.1349030] [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: 12/04/2023] [Accepted: 03/06/2024] [Indexed: 04/10/2024] Open
Abstract
Introduction Parkinson's disease (PD) is a neurodegenerative and polygenic disorder characterised by the progressive loss of neural dopamine and onset of movement disorders. We previously described eight SINE-VNTR-Alu (SVA) retrotransposon-insertion-polymorphisms (RIPs) located and expressed within the Human Leucocyte Antigen (HLA) genomic region of chromosome 6 that modulate the differential co-expression of 71 different genes including the HLA classical class I and class II genes in a Parkinson's Progression Markers Initiative (PPMI) cohort. Aims and methods In the present study, we (1) reanalysed the PPMI genomic and transcriptomic sequencing data obtained from whole blood of 1521 individuals (867 cases and 654 controls) to infer the genotypes of the transcripts expressed by eight classical HLA class I and class II genes as well as DRA and the DRB3/4/5 haplotypes, and (2) examined the statistical differences between three different PD subgroups (cases) and healthy controls (HC) for the HLA and SVA transcribed genotypes and inferred haplotypes. Results Significant differences for 57 expressed HLA alleles (21 HLA class I and 36 HLA class II alleles) up to the three-field resolution and four of eight expressed SVA were detected at p<0.05 by the Fisher's exact test within one or other of three different PD subgroups (750 individuals with PD, 57 prodromes, 60 individuals who had scans without evidence of dopamine deficits [SWEDD]), when compared against a group of 654 HCs within the PPMI cohort and when not corrected by the Bonferroni test for multiple comparisons. Fourteen of 20 significant alleles were unique to the PD-HC comparison, whereas 31 of the 57 alleles overlapped between two or more different subgroup comparisons. Only the expressed HLA-DRA*01:01:01 and -DQA1*03:01:01 protective alleles (PD v HC), the -DQA1*03:03:01 risk (HC v Prodrome) or protective allele (PD v Prodrome), the -DRA*01:01:02 and -DRB4*01:03:02 risk alleles (SWEDD v HC), and the NR_SVA_381 present genotype (PD v HC) at a 5% homozygous insertion frequency near HLA-DPA1, were significant (Pc<0.1) after Bonferroni corrections. The homologous NR_SVA_381 insertion significantly decreased the transcription levels of HLA-DPA1 and HLA-DPB1 in the PPMI cohort and its presence as a homozygous genotype is a risk factor (Pc=0.012) for PD. The most frequent NR_SVA_381 insertion haplotype in the PPMI cohort was NR_SVA_381/DPA1*02/DPB1*01 (3.7%). Although HLA C*07/B*07/DRB5*01/DRB1*15/DQB1*06 was the most frequent HLA 5-loci phased-haplotype (n, 76) in the PPMI cohort, the NR_SVA_381 insertion was present in only six of them (8%). Conclusions These data suggest that expressed SVA and HLA gene alleles in circulating white blood cells are coordinated differentially in the regulation of immune responses and the long-term onset and progression of PD, the mechanisms of which have yet to be elucidated.
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Affiliation(s)
- Jerzy K. Kulski
- Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- Health and Medical Science, Division of Immunology and Microbiology, School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Shingo Suzuki
- Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Takashi Shiina
- Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Abigail L. Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Sulev Kõks
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
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Shiina T, Kulski JK. HLA Genetics for the Human Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1444:237-258. [PMID: 38467984 DOI: 10.1007/978-981-99-9781-7_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Highly polymorphic human leukocyte antigen (HLA) molecules (alleles) expressed by different classical HLA class I and class II genes have crucial roles in the regulation of innate and adaptive immune responses, transplant rejection and in the pathogenesis of numerous infectious and autoimmune diseases. To date, over 35,000 HLA alleles have been published from the IPD-IMGT/HLA database, and specific HLA alleles and HLA haplotypes have been reported to be associated with more than 100 different diseases and phenotypes. Next generation sequencing (NGS) technology developed in recent years has provided breakthroughs in various HLA genomic/gene studies and transplant medicine. In this chapter, we review the current information on the HLA genomic structure and polymorphisms, as well as the genetic context in which numerous disease associations have been identified in this region.
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Affiliation(s)
| | - Jerzy K Kulski
- Tokai University School of Medicine, Isehara, Japan
- School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
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Kulski JK, Pfaff AL, Marney LD, Fröhlich A, Bubb VJ, Quinn JP, Koks S. Regulation of expression quantitative trait loci by SVA retrotransposons within the major histocompatibility complex. Exp Biol Med (Maywood) 2023; 248:2304-2318. [PMID: 38031415 PMCID: PMC10903234 DOI: 10.1177/15353702231209411] [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: 07/07/2023] [Accepted: 10/04/2023] [Indexed: 12/01/2023] Open
Abstract
Genomic and transcriptomic studies of expression quantitative trait loci (eQTL) revealed that SINE-VNTR-Alu (SVA) retrotransposon insertion polymorphisms (RIPs) within human genomes markedly affect the co-expression of many coding and noncoding genes by coordinated regulatory processes. This study examined the polymorphic SVA modulation of gene co-expression within the major histocompatibility complex (MHC) genomic region where more than 160 coding genes are involved in innate and adaptive immunity. We characterized the modulation of SVA RIPs utilizing the genomic and transcriptomic sequencing data obtained from whole blood of 1266 individuals in the Parkinson's Progression Markers Initiative (PPMI) cohort that included an analysis of human leukocyte antigen (HLA)-A regulation in a subpopulation of the cohort. The regulatory properties of eight SVAs located within the class I and class II MHC regions were associated with differential co-expression of 71 different genes within and 75 genes outside the MHC region. Some of the same genes were affected by two or more different SVA. Five SVA are annotated in the human genomic reference sequence GRCh38.p14/hg38, whereas the other three were novel insertions within individuals. We also examined and found distinct structural effects (long and short variants and the CT internal variants) for one of the SVA (R_SVA_24) insertions on the differential expression of the HLA-A gene within a subpopulation (550 individuals) of the PPMI cohort. This is the first time that many HLA and non-HLA genes (multilocus expression units) and splicing mechanisms have been shown to be regulated by eight structurally polymorphic SVA within the MHC genomic region by applying precise statistical analysis of RNA data derived from the blood samples of a human cohort population. This study shows that SVA within the MHC region are important regulators or rheostats of gene co-expression that might have potential roles in diversity, health, and disease.
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Affiliation(s)
- Jerzy K Kulski
- Department of Molecular Life Sciences, School of Medicine, Tokai University, Isehara, Kanagawa 259–1193, Japan
- Health and Medical Science. Division of Immunology and Microbiology, School of Biomedical Sciences, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Abigail L Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Luke D Marney
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 3BX, UK
| | - Alexander Fröhlich
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 3BX, UK
| | - Vivien J Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 3BX, UK
| | - John P Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 3BX, UK
| | - Sulev Koks
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
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Fröhlich A, Pfaff AL, Bubb VJ, Quinn JP, Koks S. Reference LINE-1 insertion polymorphisms correlate with Parkinson's disease progression and differential transcript expression in the PPMI cohort. Sci Rep 2023; 13:13857. [PMID: 37620405 PMCID: PMC10449770 DOI: 10.1038/s41598-023-41052-1] [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: 05/18/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023] Open
Abstract
Long interspersed nuclear element-1 (LINE-1/L1) retrotransposons make up 17% of the human genome. They represent one class of transposable elements with the capacity to both mobilize autonomously and in trans via the mobilization of other elements, primarily Alu and SVA elements. Reference LINE-1 elements are, by definition, found in the reference genome, however, due to the polymorphic nature of these elements, variation for presence or absence is present within the population. We used a combination of clinical and transcriptomic data from the Parkinson's Progression Markers Initiative (PPMI) and applied matrix expression quantitative trait loci analysis and linear mixed-effects models involving 114 clinical, biochemical and imaging data from the PPMI cohort to elucidate the role of reference LINE-1 insertion polymorphism on both gene expression genome-wide and progression of Parkinson's disease (PD). We demonstrate that most LINE-1 insertion polymorphisms are capable of regulating gene expression, preferentially in trans, including previously identified PD risk loci. In addition, we show that 70 LINE-1 elements were associated with longitudinal changes of at least one PD progression marker, including ipsilateral count density ratio and UPDRS scores which are indicators of degeneration and severity. In conclusion, this study highlights the effect of the polymorphic nature of LINE-1 retrotransposons on gene regulation and progression of PD which underlines the importance of analyzing transposable elements within complex diseases.
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Affiliation(s)
- Alexander Fröhlich
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Abigail L Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Vivien J Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - John P Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK.
| | - Sulev Koks
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia.
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia.
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Pfaff AL, Bubb VJ, Quinn JP, Koks S. A Genome-Wide Screen for the Exonisation of Reference SINE-VNTR-Alus and Their Expression in CNS Tissues of Individuals with Amyotrophic Lateral Sclerosis. Int J Mol Sci 2023; 24:11548. [PMID: 37511314 PMCID: PMC10380656 DOI: 10.3390/ijms241411548] [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: 06/22/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
The hominid-specific retrotransposon SINE-VNTR-Alu (SVA) is a composite element that has contributed to the genetic variation between individuals and influenced genomic structure and function. SVAs are involved in modulating gene expression and splicing patterns, altering mRNA levels and sequences, and have been associated with the development of disease. We evaluated the genome-wide effects of SVAs present in the reference genome on transcript sequence and expression in the CNS of individuals with and without the neurodegenerative disorder Amyotrophic Lateral Sclerosis (ALS). This study identified SVAs in the exons of 179 known transcripts, several of which were expressed in a tissue-specific manner, as well as 92 novel exonisation events occurring in the motor cortex. An analysis of 65 reference genome SVAs polymorphic for their presence/absence in the ALS consortium cohort did not identify any elements that were significantly associated with disease status, age at onset, and survival. However, there were transcripts, such as transferrin and HLA-A, that were differentially expressed between those with or without disease, and expression levels were associated with the genotype of proximal SVAs. This study demonstrates the functional consequences of several SVA elements altering mRNA splicing patterns and expression levels in tissues of the CNS.
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Affiliation(s)
- Abigail L Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Vivien J Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK
| | - John P Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK
| | - Sulev Koks
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
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Spirito G, Filosi M, Domenici E, Mangoni D, Gustincich S, Sanges R. Exploratory analysis of L1 retrotransposons expression in autism. Mol Autism 2023; 14:22. [PMID: 37381037 DOI: 10.1186/s13229-023-00554-5] [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: 11/03/2022] [Accepted: 06/15/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a set of highly heterogeneous neurodevelopmental diseases whose genetic etiology is not completely understood. Several investigations have relied on transcriptome analysis from peripheral tissues to dissect ASD into homogenous molecular phenotypes. Recently, analysis of changes in gene expression from postmortem brain tissues has identified sets of genes that are involved in pathways previously associated with ASD etiology. In addition to protein-coding transcripts, the human transcriptome is composed by a large set of non-coding RNAs and transposable elements (TEs). Advancements in sequencing technologies have proven that TEs can be transcribed in a regulated fashion, and their dysregulation might have a role in brain diseases. METHODS We exploited published datasets comprising RNA-seq data from (1) postmortem brain of ASD subjects, (2) in vitro cell cultures where ten different ASD-relevant genes were knocked out and (3) blood of discordant siblings. We measured the expression levels of evolutionarily young full-length transposable L1 elements and characterized the genomic location of deregulated L1s assessing their potential impact on the transcription of ASD-relevant genes. We analyzed every sample independently, avoiding to pool together the disease subjects to unmask the heterogeneity of the molecular phenotypes. RESULTS We detected a strong upregulation of intronic full-length L1s in a subset of postmortem brain samples and in in vitro differentiated neurons from iPSC knocked out for ATRX. L1 upregulation correlated with an high number of deregulated genes and retained introns. In the anterior cingulate cortex of one subject, a small number of significantly upregulated L1s overlapped with ASD-relevant genes that were significantly downregulated, suggesting the possible existence of a negative effect of L1 transcription on host transcripts. LIMITATIONS Our analyses must be considered exploratory and will need to be validated in bigger cohorts. The main limitation is given by the small sample size and by the lack of replicates for postmortem brain samples. Measuring the transcription of locus-specific TEs is complicated by the repetitive nature of their sequence, which reduces the accuracy in mapping sequencing reads to the correct genomic locus. CONCLUSIONS L1 upregulation in ASD appears to be limited to a subset of subjects that are also characterized by a general deregulation of the expression of canonical genes and an increase in intron retention. In some samples from the anterior cingulate cortex, L1s upregulation seems to directly impair the expression of some ASD-relevant genes by a still unknown mechanism. L1s upregulation may therefore identify a group of ASD subjects with common molecular features and helps stratifying individuals for novel strategies of therapeutic intervention.
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Affiliation(s)
- Giovanni Spirito
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy
- CMP3vda, Via Lavoratori Vittime del Col Du Mont 28, Aosta, Italy
| | - Michele Filosi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, TN, Italy
- Eurac Research, Institute for Biomedicine, Bolzano, BZ, Italy
| | - Enrico Domenici
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, TN, Italy
- Fondazione The Microsoft Research - University of Trento Centre for Computational and Systems Biology (COSBI), Rovereto, TN, Italy
| | - Damiano Mangoni
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy
| | - Stefano Gustincich
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy.
- CMP3vda, Via Lavoratori Vittime del Col Du Mont 28, Aosta, Italy.
| | - Remo Sanges
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience, Via Bonomea 265, 34136, Trieste, Italy.
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy.
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Kõks S, Pfaff AL, Singleton LM, Bubb VJ, Quinn JP. Non-reference genome transposable elements (TEs) have a significant impact on the progression of the Parkinson's disease. Exp Biol Med (Maywood) 2022; 247:1680-1690. [PMID: 36000172 PMCID: PMC9597212 DOI: 10.1177/15353702221117147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The pathophysiology of Parkinson's disease (PD) is a complex process of the interaction between genetic and environmental factors. Studies on the genetic component of PD have predominantly focused on single nucleotide polymorphisms (SNPs) using a cross-sectional case-control design in large genome-wide association studies. This approach while giving insight into a significant portion of the genetics of PD does not fully account for all the genetic components resulting in missing heritability. In this study, we approached this problem by focusing on the non-reference genome transposable elements (TEs) and their impact on the progression of PD using a longitudinal study design within the Parkinson's progression markers initiative (PPMI) cohort. We analyzed 2886 Alu repeats, 360 LINE1 and 128 SINE-VNTR-Alus (SVAs) that were called from the whole-genome sequence data which are not within the reference genome. The presence or absence of these non-reference TE variants is known as a retrotransposon insertion polymorphism, and measuring this polymorphism describes the impact of TEs on the traits. The variations for the presence or absence of the non-reference TE elements were modeled to align with the changes in the 114 outcome measures during the five-year follow-up period of the PPMI cohort. Linear mixed-effects models were used, and many TEs were found to have a highly significant effect on the longitudinal changes in the clinically important PD outcomes such as UPDRS subscale II, UPDRS total scores, and modified Schwab and England ADL scale. In addition, the progression of several imaging and functional measures, including the Caudate/Putamen ratio and levodopa equivalent daily dose (LEDD) were also significantly affected by the TEs. In conclusion, this study identified the overwhelming effect of the non-reference TEs on the progression of PD and is a good example of the impact the variations in the "junk DNA" have on complex diseases.
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Affiliation(s)
- Sulev Kõks
- Perron Institute for Neurological and
Translational Science, Perth, WA 6009, Australia,Centre for Molecular Medicine and
Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia,Sulev Kõks.
| | - Abigail L Pfaff
- Perron Institute for Neurological and
Translational Science, Perth, WA 6009, Australia,Centre for Molecular Medicine and
Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Lewis M Singleton
- Perron Institute for Neurological and
Translational Science, Perth, WA 6009, Australia
| | - Vivien J Bubb
- Department of Pharmacology and
Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of
Liverpool, Liverpool L69 3BX, UK
| | - John P Quinn
- Department of Pharmacology and
Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of
Liverpool, Liverpool L69 3BX, UK
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Pfaff AL, Singleton LM, Kõks S. Mechanisms of disease-associated SINE-VNTR-Alus. Exp Biol Med (Maywood) 2022; 247:756-764. [PMID: 35387528 DOI: 10.1177/15353702221082612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
SINE-VNTR-Alus (SVAs) are the youngest retrotransposon family in the human genome. Their ongoing mobilization has generated genetic variation within the human population. At least 24 insertions to date, detailed in this review, have been associated with disease. The predominant mechanisms through which this occurs are alterations to normal splicing patterns, exonic insertions causing loss-of-function mutations, and large genomic deletions. Dissecting the functional impact of these SVAs and the mechanism through which they cause disease provides insight into the consequences of their presence in the genome and how these elements could influence phenotypes. Many of these disease-associated SVAs have been difficult to characterize and would not have been identified through routine analyses. However, the number identified has increased in recent years as DNA and RNA sequencing data became more widely available. Therefore, as the search for complex structural variation in disease continues, it is likely to yield further disease-causing SVA insertions.
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Affiliation(s)
- Abigail L Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Lewis M Singleton
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
| | - Sulev Kõks
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
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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.
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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
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