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Du J, Nakachi Y, Murata Y, Kiyota E, Kato T, Bundo M, Iwamoto K. Exploration of cell type-specific somatic mutations in schizophrenia and the impact of maternal immune activation on the somatic mutation profile in the brain. Psychiatry Clin Neurosci 2024; 78:237-247. [PMID: 38334156 DOI: 10.1111/pcn.13640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/10/2023] [Accepted: 12/20/2023] [Indexed: 02/10/2024]
Abstract
AIM Schizophrenia (SZ) is a severe psychiatric disorder caused by the interaction of genetic and environmental factors. Although somatic mutations that occur in the brain after fertilization may play an important role in the cause of SZ, their frequencies and patterns in the brains of patients and related animal models have not been well studied. This study aimed to find somatic mutations related to the pathophysiology of SZ. METHODS We performed whole-exome sequencing (WES) of neuronal and nonneuronal nuclei isolated from the postmortem prefrontal cortex of patients with SZ (n = 10) and controls (n = 10). After detecting somatic mutations, we explored the similarities and differences in shared common mutations between two cell types and cell type-specific mutations. We also performed WES of prefrontal cortex samples from an animal model of SZ based on maternal immune activation (MIA) and explored the possible impact of MIA on the patterns of somatic mutations. RESULTS We did not find quantitative differences in somatic mutations but found higher variant allele fractions of neuron-specific mutations in patients with SZ. In the mouse model, we found a larger variation in the number of somatic mutations in the offspring of MIA mice, with the occurrence of somatic mutations in neurodevelopment-related genes. CONCLUSION Somatic mutations occurring at an earlier stage of brain cell differentiation toward neurons may be important for the cause of SZ. MIA may affect somatic mutation profiles in the brain.
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Affiliation(s)
- Jianbin Du
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yutaka Nakachi
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yui Murata
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Emi Kiyota
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
- Department of Psychiatry and Behavioral Science, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Miki Bundo
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
| | - Kazuya Iwamoto
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Japan
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Nishioka M, Takayama J, Sakai N, Kazuno AA, Ishiwata M, Ueda J, Hayama T, Fujii K, Someya T, Kuriyama S, Tamiya G, Takata A, Kato T. Deep exome sequencing identifies enrichment of deleterious mosaic variants in neurodevelopmental disorder genes and mitochondrial tRNA regions in bipolar disorder. Mol Psychiatry 2023; 28:4294-4306. [PMID: 37248276 PMCID: PMC10827672 DOI: 10.1038/s41380-023-02096-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/31/2023]
Abstract
Bipolar disorder (BD) is a global medical issue, afflicting around 1% of the population with manic and depressive episodes. Despite various genetic studies, the genetic architecture and pathogenesis of BD have not been fully resolved. Besides germline variants, postzygotic mosaic variants are proposed as new candidate mechanisms contributing to BD. Here, we performed extensive deep exome sequencing (DES, ~300×) and validation experiments to investigate the roles of mosaic variants in BD with 235 BD cases (194 probands of trios and 41 single cases) and 39 controls. We found an enrichment of developmental disorder (DD) genes in the genes hit by deleterious mosaic variants in BD (P = 0.000552), including a ClinVar-registered pathogenic variant in ARID2. An enrichment of deleterious mosaic variants was also observed for autism spectrum disorder (ASD) genes (P = 0.000428). The proteins coded by the DD/ASD genes with non-synonymous mosaic variants in BD form more protein-protein interaction than expected, suggesting molecular mechanisms shared with DD/ASD but restricted to a subset of cells in BD. We also found significant enrichment of mitochondrial heteroplasmic variants, another class of mosaic variants, in mitochondrial tRNA genes in BD (P = 0.0102). Among them, recurrent m.3243 A > G variants known as causal for mitochondrial diseases were found in two unrelated BD probands with allele fractions of 5-12%, lower than in mitochondrial diseases. Despite the limitation of using peripheral tissues, our DES investigation supports the possible contribution of deleterious mosaic variants in the nuclear genome responsible for severer phenotypes, such as DD/ASD, to the risk of BD and further demonstrates that the same paradigm can be applied to the mitochondrial genome. These results, as well as the enrichment of heteroplasmic mitochondrial tRNA variants in BD, add a new piece to the understanding of the genetic architecture of BD and provide general insights into the pathological roles of mosaic variants in human diseases.
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Affiliation(s)
- Masaki Nishioka
- Department of Psychiatry and Behavioral Science, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
- Department of Molecular Pathology of Mood Disorders, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Jun Takayama
- Department of AI and Innovative Medicine, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-Ku, Sendai, Miyagi, 980-8575, Japan
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-Ku, Sendai, Miyagi, 980-8573, Japan
- Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan
| | - Naomi Sakai
- Department of Psychiatry and Behavioral Science, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - An-A Kazuno
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Mizuho Ishiwata
- Department of Psychiatry and Behavioral Science, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Junko Ueda
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Takashi Hayama
- Yokohama Mental Clinic Totsuka, 494-8 Kamikurata-cho, Totsuka-ku, Yokohama, 244-0816, Japan
| | - Kumiko Fujii
- Department of Psychiatry, Shiga University of Medical Science, Seta Tsukinowa-Cho, Otsu, Shiga, 520-2192, Japan
| | - Toshiyuki Someya
- Department of Psychiatry, Niigata University Graduate School of Medical and Dental Sciences, 757 Asahimachidori-ichibancho, Chuo-ku, Niigata, 951-8510, Japan
| | - Shinichi Kuriyama
- Department of Preventive Medicine and Epidemiology, Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-Ku, Sendai, Miyagi, 980-8573, Japan
- Department of Molecular Epidemiology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-Ku, Sendai, Miyagi, 980-8575, Japan
| | - Gen Tamiya
- Department of AI and Innovative Medicine, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-Ku, Sendai, Miyagi, 980-8575, Japan
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-Ku, Sendai, Miyagi, 980-8573, Japan
- Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan
| | - Atsushi Takata
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
| | - Tadafumi Kato
- Department of Psychiatry and Behavioral Science, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
- Department of Molecular Pathology of Mood Disorders, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
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Menon V, Brash DE. Next-generation sequencing methodologies to detect low-frequency mutations: "Catch me if you can". MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2023; 792:108471. [PMID: 37716438 PMCID: PMC10843083 DOI: 10.1016/j.mrrev.2023.108471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/18/2023]
Abstract
Mutations, the irreversible changes in an organism's DNA sequence, are present in tissues at a variant allele frequency (VAF) ranging from ∼10-8 per bp for a founder mutation to ∼10-3 for a histologically normal tissue sample containing several independent clones - compared to 1%- 50% for a heterozygous tumor mutation or a polymorphism. The rarity of these events poses a challenge for accurate clinical diagnosis and prognosis, toxicology, and discovering new disease etiologies. Standard Next-Generation Sequencing (NGS) technologies report VAFs as low as 0.5% per nt, but reliably observing rarer precursor events requires additional sophistication to measure ultralow-frequency mutations. We detail the challenge; define terms used to characterize the results, which vary between laboratories and sometimes conflict between biologists and bioinformaticists; and describe recent innovations to improve standard NGS methodologies including: single-strand consensus sequence methods such as Safe-SeqS and SiMSen-Seq; tandem-strand consensus sequence methods such as o2n-Seq and SMM-Seq; and ultrasensitive parent-strand consensus sequence methods such as DuplexSeq, PacBio HiFi, SinoDuplex, OPUSeq, EcoSeq, BotSeqS, Hawk-Seq, NanoSeq, SaferSeq, and CODEC. Practical applications are also noted. Several methods quantify VAF down to 10-5 at a nt and mutation frequency (MF) in a target region down to 10-7 per nt. By expanding to > 1 Mb of sites never observed twice, thus forgoing VAF, other methods quantify MF < 10-9 per nt or < 15 errors per haploid genome. Clonal expansion cannot be directly distinguished from independent mutations by sequencing, so it is essential for a paper to report whether its MF counted only different mutations - the minimum independent-mutation frequency MFminI - or all mutations observed including recurrences - the larger maximum independent-mutation frequency MFmaxI which may reflect clonal expansion. Ultrasensitive methods reveal that, without their use, even mutations with VAF 0.5-1% are usually spurious.
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Affiliation(s)
- Vijay Menon
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA.
| | - Douglas E Brash
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; Department of Dermatology, Yale School of Medicine, New Haven, CT 06520-8059, USA; Yale Cancer Center, Yale School of Medicine, New Haven, CT 06520-8028, USA.
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4
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Nakamura T, Takata A. The molecular pathology of schizophrenia: an overview of existing knowledge and new directions for future research. Mol Psychiatry 2023; 28:1868-1889. [PMID: 36878965 PMCID: PMC10575785 DOI: 10.1038/s41380-023-02005-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 03/08/2023]
Abstract
Despite enormous efforts employing various approaches, the molecular pathology in the schizophrenia brain remains elusive. On the other hand, the knowledge of the association between the disease risk and changes in the DNA sequences, in other words, our understanding of the genetic pathology of schizophrenia, has dramatically improved over the past two decades. As the consequence, now we can explain more than 20% of the liability to schizophrenia by considering all analyzable common genetic variants including those with weak or no statistically significant association. Also, a large-scale exome sequencing study identified single genes whose rare mutations substantially increase the risk for schizophrenia, of which six genes (SETD1A, CUL1, XPO7, GRIA3, GRIN2A, and RB1CC1) showed odds ratios larger than ten. Based on these findings together with the preceding discovery of copy number variants (CNVs) with similarly large effect sizes, multiple disease models with high etiological validity have been generated and analyzed. Studies of the brains of these models, as well as transcriptomic and epigenomic analyses of patient postmortem tissues, have provided new insights into the molecular pathology of schizophrenia. In this review, we overview the current knowledge acquired from these studies, their limitations, and directions for future research that may redefine schizophrenia based on biological alterations in the responsible organ rather than operationalized criteria.
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Affiliation(s)
- Takumi Nakamura
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Atsushi Takata
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
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5
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Li Z, Min S, Alliey-Rodriguez N, Giase G, Cheng L, Craig DW, Faulkner GJ, Asif H, Liu C, Gershon ES. Single-neuron whole genome sequencing identifies increased somatic mutation burden in Alzheimer's disease related genes. Neurobiol Aging 2023; 123:222-232. [PMID: 36599749 DOI: 10.1016/j.neurobiolaging.2022.12.002] [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: 05/31/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 12/15/2022]
Abstract
Accumulation of somatic mutations in human neurons is associated with aging and neurodegeneration. To shed light on the somatic mutational burden in Alzheimer's disease (AD) neurons and get more insight into the role of somatic mutations in AD pathogenesis, we performed single-neuron whole genome sequencing to detect genome-wide somatic mutations (single nucleotide variants (SNVs) and Indels) in 96 single prefrontal cortex neurons from 8 AD patients and 8 elderly controls. We found that the mutational burden is ∼3000 somatic mutations per neuron genome in elderly subjects. AD patients have increased somatic mutation burden in AD-related annotation categories, including AD risk genes and differentially expressed genes in AD neurons. Mutational signature analysis showed somatic SNVs (sSNVs) primarily caused by aging and oxidative DNA damage processes but no significant difference was detected between AD and controls. Additionally, functional somatic mutations identified in AD patients showed significant enrichment in several AD-related pathways, including AD pathway, Notch-signaling pathway and Calcium-signaling pathway. These findings provide genetic insights into how somatic mutations may alter the function of single neurons and exert their potential roles in the pathogenesis of AD.
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Affiliation(s)
- Zongchang Li
- Department of Psychiatry, The Second Xiangya Hospital; Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China; Department of Psychiatry and Behavioral Neurosciences, University of Chicago, Chicago, IL, USA
| | - Shishi Min
- Department of Psychiatry, The Second Xiangya Hospital; Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China; Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, USA; Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ney Alliey-Rodriguez
- Department of Psychiatry and Behavioral Neurosciences, University of Chicago, Chicago, IL, USA
| | - Gina Giase
- School of Public Health, University of Illinois at Chicago, Chicago, IL, USA
| | - Lijun Cheng
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - David Wesley Craig
- Department of Translational Genomics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Geoffrey J Faulkner
- Mater Research Institute - University of Queensland, Woolloongabba, Queensland, Australia; Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Huma Asif
- Department of Psychiatry and Behavioral Neurosciences, University of Chicago, Chicago, IL, USA.
| | - Chunyu Liu
- Department of Psychiatry, The Second Xiangya Hospital; Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China; Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, USA; School of Psychology, Shaanxi Normal University, Xi'an, China.
| | - Elliot S Gershon
- Department of Psychiatry and Behavioral Neurosciences, University of Chicago, Chicago, IL, USA; Department of Human Genetics, University of Chicago, Chicago, IL, USA.
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Southwood D, Singh S, Chatterton Z. Brain-derived cell-free DNA. Neural Regen Res 2022; 17:2213-2214. [PMID: 35259835 PMCID: PMC9083148 DOI: 10.4103/1673-5374.335794] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/30/2021] [Accepted: 11/09/2021] [Indexed: 11/29/2022] Open
Affiliation(s)
- Dean Southwood
- Brain and Mind Center, School of Medical Sciences, Department of Neuroscience, The University of Sydney, Camperdown, NSW, Australia
| | - Sanyukta Singh
- Brain and Mind Center, School of Medical Sciences, Department of Neuroscience, The University of Sydney, Camperdown, NSW, Australia
| | - Zac Chatterton
- Brain and Mind Center, School of Medical Sciences, Department of Neuroscience, The University of Sydney, Camperdown, NSW, Australia
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7
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Joshi R, Salton SRJ. Neurotrophin Crosstalk in the Etiology and Treatment of Neuropsychiatric and Neurodegenerative Disease. Front Mol Neurosci 2022; 15:932497. [PMID: 35909451 PMCID: PMC9335126 DOI: 10.3389/fnmol.2022.932497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/23/2022] [Indexed: 12/27/2022] Open
Abstract
This article reviews the current progress in our understanding of the mechanisms by which growth factors, including brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), and select neurotrophin-regulated gene products, such as VGF (non-acronymic) and VGF-derived neuropeptides, function in the central nervous system (CNS) to modulate neuropsychiatric and neurodegenerative disorders, with a discussion of the possible therapeutic applications of these growth factors to major depressive disorder (MDD) and Alzheimer’s disease (AD). BDNF and VEGF levels are generally decreased regionally in the brains of MDD subjects and in preclinical animal models of depression, changes that are associated with neuronal atrophy and reduced neurogenesis, and are reversed by conventional monoaminergic and novel ketamine-like antidepressants. Downstream of neurotrophins and their receptors, VGF was identified as a nerve growth factor (NGF)- and BDNF-inducible secreted protein and neuropeptide precursor that is produced and trafficked throughout the CNS, where its expression is greatly influenced by neuronal activity and exercise, and where several VGF-derived peptides modulate neuronal activity, function, proliferation, differentiation, and survival. Moreover, levels of VGF are reduced in the CSF of AD subjects, where it has been repetitively identified as a disease biomarker, and in the hippocampi of subjects with MDD, suggesting possible shared mechanisms by which reduced levels of VGF and other proteins that are similarly regulated by neurotrophin signaling pathways contribute to and potentially drive the pathogenesis and progression of co-morbid neuropsychiatric and neurodegenerative disorders, particularly MDD and AD, opening possible therapeutic windows.
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Affiliation(s)
- Rajeev Joshi
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Stephen R. J. Salton
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, United States
- Brookdale Department of Geriatrics and Palliative Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- *Correspondence: Stephen R. J. Salton,
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Wasilewska K, Gambin T, Rydzanicz M, Szczałuba K, Płoski R. Postzygotic mutations and where to find them - Recent advances and future implications in the field of non-neoplastic somatic mosaicism. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2022; 790:108426. [PMID: 35690331 DOI: 10.1016/j.mrrev.2022.108426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 05/05/2022] [Accepted: 06/03/2022] [Indexed: 01/01/2023]
Abstract
The technological progress of massively parallel sequencing (MPS) has triggered a remarkable development in the research on postzygotic mutations. Although the overwhelming majority of studies in the field focus on oncogenesis, non-neoplastic diseases are attracting more and more attention. The aim of this review was to summarize some of the most recent findings in the field of somatic mosaicism in diseases other than neoplastic events. We discuss the abundance and role of postzygotic mutations, with a special emphasis on disorders which occur only in a mosaic form (obligatory mosaic diseases; OMDs). Based on the list of OMDs compiled from the published literature and three databases (OMIM, Orphanet and MosaicBase), we demonstrate the prevalence of cancer-related genes across OMDs and suggest other sources to further explore OMDs and OMD-related genes. Additionally, we comment on some practical aspects related to mosaic diseases, such as approaches to tissue sampling, the MPS coverage required to detect variants at a very low frequency, as well as on bioinformatic and molecular tools dedicated to detect somatic mutations in MPS data.
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Affiliation(s)
- Krystyna Wasilewska
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawińskiego 3c, 02-106 Warsaw, Poland
| | - Tomasz Gambin
- Institute of Computer Science, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawińskiego 3c, 02-106 Warsaw, Poland
| | - Krzysztof Szczałuba
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawińskiego 3c, 02-106 Warsaw, Poland
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawińskiego 3c, 02-106 Warsaw, Poland.
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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.
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Affiliation(s)
| | | | | | - Bing Lang
- *Correspondence: Bing Lang, ; Xiao-Ping Wang,
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10
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Lee S, Lee JH. Brain somatic mutations as RNA therapeutic targets in neurological disorders. Ann N Y Acad Sci 2022; 1514:11-20. [PMID: 35527236 DOI: 10.1111/nyas.14786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Research into the genetic etiology of a neurological disorder can provide directions for genetic diagnosis and targeted therapy. In the past, germline mutations, which are transmitted from parents or newly arise from parental germ cells, were considered as major genetic causes of neurological disorders. However, recent evidence has shown that somatic mutations in the brain, which can arise from neural stem cells during development or over aging, account for a significant number of brain disorders, ranging from neurodevelopmental, neurodegenerative, and neuropsychiatric to neoplastic disease. Moreover, the identification of disease-causing somatic mutations or mutated genes has provided new insights into molecular pathogenesis and unveiled potential therapeutic targets for treating neurological disorders that have few, or no, therapeutic options. RNA therapeutics, including antisense oligonucleotide (ASO) and small interfering RNA (siRNA), are emerging as promising therapeutic tools for treating genetic neurological disorders. As the number of approved and investigational ASO and siRNA drugs for neurological disorders associated with germline mutations increases, they may also prove to be attractive modalities for treating neurologic disorders resulting from somatic mutations. In this perspective, we highlight several neurological diseases caused by brain somatic mutations and discuss the potential role of RNA therapeutics in these conditions.
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Affiliation(s)
- Sungyul Lee
- SoVarGen Co., Ltd., Daejeon, Republic of Korea
| | - Jeong Ho Lee
- SoVarGen Co., Ltd., Daejeon, Republic of Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute Science and Technology (KAIST), KAIST BioMedical Research Center, Daejeon, Republic of Korea
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11
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Genetic mosaicism in the human brain: from lineage tracing to neuropsychiatric disorders. Nat Rev Neurosci 2022; 23:275-286. [PMID: 35322263 DOI: 10.1038/s41583-022-00572-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 12/18/2022]
Abstract
Genetic mosaicism is the result of the accumulation of somatic mutations in the human genome starting from the first postzygotic cell generation and continuing throughout the whole life of an individual. The rapid development of next-generation and single-cell sequencing technologies is now allowing the study of genetic mosaicism in normal tissues, revealing unprecedented insights into their clonal architecture and physiology. The somatic variant repertoire of an adult human neuron is the result of somatic mutations that accumulate in the brain by different mechanisms and at different rates during development and ageing. Non-pathogenic developmental mutations function as natural barcodes that once identified in deep bulk or single-cell sequencing can be used to retrospectively reconstruct human lineages. This approach has revealed novel insights into the clonal structure of the human brain, which is a mosaic of clones traceable to the early embryo that contribute differentially to the brain and distinct areas of the cortex. Some of the mutations happening during development, however, have a pathogenic effect and can contribute to some epileptic malformations of cortical development and autism spectrum disorder. In this Review, we discuss recent findings in the context of genetic mosaicism and their implications for brain development and disease.
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Deb BK, Bateup HS. Modeling Somatic Mutations Associated With Neurodevelopmental Disorders in Human Brain Organoids. Front Mol Neurosci 2022; 14:787243. [PMID: 35058746 PMCID: PMC8764387 DOI: 10.3389/fnmol.2021.787243] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are a collection of diseases with early life onset that often present with developmental delay, cognitive deficits, and behavioral conditions. In some cases, severe outcomes such as brain malformations and intractable epilepsy can occur. The mutations underlying NDDs may be inherited or de novo, can be gain- or loss-of-function, and can affect one or more genes. Recent evidence indicates that brain somatic mutations contribute to several NDDs, in particular malformations of cortical development. While advances in sequencing technologies have enabled the detection of these somatic mutations, the mechanisms by which they alter brain development and function are not well understood due to limited model systems that recapitulate these events. Human brain organoids have emerged as powerful models to study the early developmental events of the human brain. Brain organoids capture the developmental progression of the human brain and contain human-enriched progenitor cell types. Advances in human stem cell and genome engineering provide an opportunity to model NDD-associated somatic mutations in brain organoids. These organoids can be tracked throughout development to understand the impact of somatic mutations on early human brain development and function. In this review, we discuss recent evidence that somatic mutations occur in the developing human brain, that they can lead to NDDs, and discuss how they could be modeled using human brain organoids.
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Affiliation(s)
- Bipan K. Deb
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
- *Correspondence: Helen S. Bateup
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Kisby GE, Spencer PS. Genotoxic Damage During Brain Development Presages Prototypical Neurodegenerative Disease. Front Neurosci 2021; 15:752153. [PMID: 34924930 PMCID: PMC8675606 DOI: 10.3389/fnins.2021.752153] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/20/2021] [Indexed: 01/15/2023] Open
Abstract
Western Pacific Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex (ALS/PDC) is a disappearing prototypical neurodegenerative disorder (tau-dominated polyproteinopathy) linked with prior exposure to phytogenotoxins in cycad seed used for medicine and/or food. The principal cycad genotoxin, methylazoxymethanol (MAM), forms reactive carbon-centered ions that alkylate nucleic acids in fetal rodent brain and, depending on the timing of systemic administration, induces persistent developmental abnormalities of the cortex, hippocampus, cerebellum, and retina. Whereas administration of MAM prenatally or postnatally can produce animal models of epilepsy, schizophrenia or ataxia, administration to adult animals produces little effect on brain structure or function. The neurotoxic effects of MAM administered to rats during cortical brain development (specifically, gestation day 17) are used to model the histological, neurophysiological and behavioral deficits of human schizophrenia, a condition that may precede or follow clinical onset of motor neuron disease in subjects with sporadic ALS and ALS/PDC. While studies of migrants to and from communities impacted by ALS/PDC indicate the degenerative brain disorder may be acquired in juvenile and adult life, a proportion of indigenous cases shows neurodevelopmental aberrations in the cerebellum and retina consistent with MAM exposure in utero. MAM induces specific patterns of DNA damage and repair that associate with increased tau expression in primary rat neuronal cultures and with brain transcriptional changes that parallel those associated with human ALS and Alzheimer’s disease. We examine MAM in relation to neurodevelopment, epigenetic modification, DNA damage/replicative stress, genomic instability, somatic mutation, cell-cycle reentry and cellular senescence. Since the majority of neurodegenerative disease lacks a solely inherited genetic basis, research is needed to explore the hypothesis that early-life exposure to genotoxic agents may trigger or promote molecular events that culminate in neurodegeneration.
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Affiliation(s)
- Glen E Kisby
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Lebanon, OR, United States
| | - Peter S Spencer
- School of Medicine (Neurology), Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, United States
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Gozes I. A Different Outlook at Psychiatric and Neurological Diseases: Brain Somatic Mutations Are Implicated in Schizophrenia. Biol Psychiatry 2021; 90:6-8. [PMID: 34140120 DOI: 10.1016/j.biopsych.2021.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/25/2022]
Affiliation(s)
- Illana Gozes
- The Elton Laboratory for Molecular Neuroendocrinology, Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv, Israel.
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