1
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Quintas S, Sanles-Falagan R, Berbís MÁ. I 123-FP-CIT (DaTSCAN) SPECT beyond the Most Common Causes of Parkinsonism: A Systematic Review. Mov Disord Clin Pract 2024. [PMID: 38693679 DOI: 10.1002/mdc3.14055] [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: 11/14/2023] [Revised: 01/23/2024] [Accepted: 03/30/2024] [Indexed: 05/03/2024] Open
Abstract
BACKGROUND As the diagnosis of Parkinson's disease (PD) is fundamentally clinical, the usefulness of ioflupane (123I) single-photon emission computed tomography (SPECT) or DaTSCAN as a diagnostic tool has been a matter of debate for years. The performance of DaTSCAN is generally recommended in the follow-up of patients with a clinically uncertain diagnosis, especially in those with a suspected essential tremor, drug-induced parkinsonism, or vascular parkinsonism. However, there is a dearth of DaTSCAN findings regarding neurodegenerative parkinsonisms besides PD and atypical parkinsonisms. To date, a specific nigrostriatal dopamine uptake pattern that would help differentiate PD from the most frequent atypical parkinsonisms is yet to be described. This fact is further complicated by the possible visualization of abnormalities in the uptake pattern in patients with rarer neurodegenerative parkinsonisms. OBJECTIVES We aimed to summarize the current literature regarding DaTSCAN findings in patients with rare neurodegenerative parkinsonisms. METHODS The PubMed database was systematically screened for studies in English or Spanish up to October 15, 2023, using search terms "DaTSCAN", "ioflupane", "DaT-SPECT", "123I-FP-CIT SPECT", "dopamine transporter imaging", and "[123I] FP-CIT SPECT". Duplicated publications and studies regarding PD, atypical parkinsonisms, dystonia-parkinsonism, essential tremor, and parkinsonism due to non-degenerative causes were excluded. RESULTS The obtained results were reviewed and summarized, including DaTSCAN findings in fragile X-associated tremor/ataxia syndrome, prion diseases, Huntington's disease, spinocerebellar ataxia, hereditary spastic paraparesis, metabolic disorders, and other diseases (anti-IgLON5 disease, ring chromosome 20 syndrome, chorea-acanthocytosis, and neuronal ceroid lipofuscinosis). CONCLUSIONS This review highlights the need to determine in the future the utility and cost-effectiveness of DaTSCAN, both as a diagnostic and a prognostic tool, in patients with parkinsonian symptoms in rare neurodegenerative diseases.
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Affiliation(s)
- Sonia Quintas
- Department of Neurology, La Princesa University Hospital, Madrid, Spain
| | | | - M Álvaro Berbís
- Department of Radiology, HT Médica, San Juan de Dios Hospital, Córdoba, Spain
- Faculty of Medicine, Autonomous University of Madrid, Madrid, Spain
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2
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Bocoum A, Ouologuem M, Cissé L, Essop F, dit Papa Coulibaly S, Botha N, Cissé CAK, dit Baneye Maiga A, Krause A, Landouré G. The First Case of Huntington's Disease like 2 in Mali, West Africa. Tremor Other Hyperkinet Mov (N Y) 2024; 14:15. [PMID: 38617831 PMCID: PMC11011944 DOI: 10.5334/tohm.859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/07/2024] [Indexed: 04/16/2024] Open
Abstract
Background Huntington's disease like 2 (HDL2) has been reported exclusively in patients with African ancestry, mostly originating from South Africa. Case report We report three patients in Mali including a proband and his two children who have been examined by neurologists and psychiatrists after giving consent. They were aged between 28 and 56 years old. Psychiatric symptoms were predominant in the two younger patients while the father presented mainly with motor symptoms. Genetic testing identified a heterozygous 40 CTG repeat expansion in the Junctophilin-3 (JPH3) gene in all three patients. Discussion This study supports the hypothesis that HDL2 may be widely spread across Africa. Highlights We report here the first case of HDL2 in West Africa, suggesting that HDL2 is widely spread across African continent, and increasing access to genetic testing could uncover other cases.
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Affiliation(s)
| | | | | | - Fahmida Essop
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand, Johannesburg, South Africa
| | | | - Nadine Botha
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand, Johannesburg, South Africa
| | | | | | - Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand, Johannesburg, South Africa
| | - Guida Landouré
- Facultéde Médecine et d’Odontostomatologie, USTTB, Bamako, Mali
- Service de Neurologie, CHU Point “G”, Bamako, Mali
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3
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Hall DD, Takeshima H, Song LS. Structure, Function, and Regulation of the Junctophilin Family. Annu Rev Physiol 2024; 86:123-147. [PMID: 37931168 PMCID: PMC10922073 DOI: 10.1146/annurev-physiol-042022-014926] [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: 11/08/2023]
Abstract
In both excitable and nonexcitable cells, diverse physiological processes are linked to different calcium microdomains within nanoscale junctions that form between the plasma membrane and endo-sarcoplasmic reticula. It is now appreciated that the junctophilin protein family is responsible for establishing, maintaining, and modulating the structure and function of these junctions. We review foundational findings from more than two decades of research that have uncovered how junctophilin-organized ultrastructural domains regulate evolutionarily conserved biological processes. We discuss what is known about the junctophilin family of proteins. Our goal is to summarize the current knowledge of junctophilin domain structure, function, and regulation and to highlight emerging avenues of research that help our understanding of the transcriptional, translational, and post-translational regulation of this gene family and its roles in health and during disease.
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Affiliation(s)
- Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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4
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Sun S, Zhao G, Jia M, Jiang Q, Li S, Wang H, Li W, Wang Y, Bian X, Zhao YG, Huang X, Yang G, Cai H, Pastor-Pareja JC, Ge L, Zhang C, Hu J. Stay in touch with the endoplasmic reticulum. SCIENCE CHINA. LIFE SCIENCES 2024; 67:230-257. [PMID: 38212460 DOI: 10.1007/s11427-023-2443-9] [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: 03/19/2023] [Accepted: 08/28/2023] [Indexed: 01/13/2024]
Abstract
The endoplasmic reticulum (ER), which is composed of a continuous network of tubules and sheets, forms the most widely distributed membrane system in eukaryotic cells. As a result, it engages a variety of organelles by establishing membrane contact sites (MCSs). These contacts regulate organelle positioning and remodeling, including fusion and fission, facilitate precise lipid exchange, and couple vital signaling events. Here, we systematically review recent advances and converging themes on ER-involved organellar contact. The molecular basis, cellular influence, and potential physiological functions for ER/nuclear envelope contacts with mitochondria, Golgi, endosomes, lysosomes, lipid droplets, autophagosomes, and plasma membrane are summarized.
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Affiliation(s)
- Sha Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Gan Zhao
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Mingkang Jia
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Qing Jiang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Shulin Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Haibin Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenjing Li
- Laboratory of Computational Biology & Machine Intelligence, School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunyun Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xin Bian
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
| | - Yan G Zhao
- Brain Research Center, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Ge Yang
- Laboratory of Computational Biology & Machine Intelligence, School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Huaqing Cai
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Jose C Pastor-Pareja
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Institute of Neurosciences, Consejo Superior de Investigaciones Cientfflcas-Universidad Miguel Hernandez, San Juan de Alicante, 03550, Spain.
| | - Liang Ge
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Chuanmao Zhang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China.
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
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5
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Krause A, Anderson DG, Ferreira-Correia A, Dawson J, Baine-Savanhu F, Li PP, Margolis RL. Huntington disease-like 2: insight into neurodegeneration from an African disease. Nat Rev Neurol 2024; 20:36-49. [PMID: 38114648 DOI: 10.1038/s41582-023-00906-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2023] [Indexed: 12/21/2023]
Abstract
Huntington disease (HD)-like 2 (HDL2) is a rare genetic disease caused by an expanded trinucleotide repeat in the JPH3 gene (encoding junctophilin 3) that shows remarkable clinical similarity to HD. To date, HDL2 has been reported only in patients with definite or probable African ancestry. A single haplotype background is shared by patients with HDL2 from different populations, supporting a common African origin for the expansion mutation. Nevertheless, outside South Africa, reports of patients with HDL2 in Africa are scarce, probably owing to limited clinical services across the continent. Systematic comparisons of HDL2 and HD have revealed closely overlapping motor, cognitive and psychiatric features and similar patterns of cerebral and striatal atrophy. The pathogenesis of HDL2 remains unclear but it is proposed to occur through several mechanisms, including loss of protein function and RNA and/or protein toxicity. This Review summarizes our current knowledge of this African-specific HD phenocopy and highlights key areas of overlap between HDL2 and HD. Given the aforementioned similarities in clinical phenotype and pathology, an improved understanding of HDL2 could provide novel insights into HD and other neurodegenerative and/or trinucleotide repeat expansion disorders.
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Affiliation(s)
- Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - David G Anderson
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- University of Glasgow, Department of Neurology, Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, UK
| | - Aline Ferreira-Correia
- Department of Psychology, School of Human and Community Development, Faculty of Humanities, University of the Witwatersrand, Johannesburg, South Africa
| | - Jessica Dawson
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Fiona Baine-Savanhu
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Pan P Li
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Russell L Margolis
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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6
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Neiman AM. Pharmacological interventions for lipid transport disorders. Front Neurosci 2023; 17:1321250. [PMID: 38156273 PMCID: PMC10752963 DOI: 10.3389/fnins.2023.1321250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 11/29/2023] [Indexed: 12/30/2023] Open
Abstract
The recent discovery that defects in inter-organelle lipid transport are at the heart of several neurological and neurodegenerative disorders raises the challenge of identifying therapeutic strategies to correct lipid transport defects. This perspective highlights two potential strategies suggested by the study of lipid transport in budding yeast. In the first approach, small molecules are proposed that enhance the lipid transfer activity of VPS13 proteins and thereby compensate for reduced transport. In the second approach, molecules that act as inter-organelle tethers could be used to create artificial contact sites and bypass the loss of endogenous contacts.
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Affiliation(s)
- Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
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7
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Guillén-Samander A, De Camilli P. Endoplasmic Reticulum Membrane Contact Sites, Lipid Transport, and Neurodegeneration. Cold Spring Harb Perspect Biol 2023; 15:a041257. [PMID: 36123033 PMCID: PMC10071438 DOI: 10.1101/cshperspect.a041257] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Endoplasmic Reticulum (ER) is an endomembrane system that plays a multiplicity of roles in cell physiology and populates even the most distal cell compartments, including dendritic tips and axon terminals of neurons. Some of its functions are achieved by a cross talk with other intracellular membranous organelles and with the plasma membrane at membrane contacts sites (MCSs). As the ER synthesizes most membrane lipids, lipid exchanges mediated by lipid transfer proteins at MCSs are a particularly important aspect of this cross talk, which synergizes with the cross talk mediated by vesicular transport. Several mutations of genes that encode proteins localized at ER MCSs result in familial neurodegenerative diseases, emphasizing the importance of the normal lipid traffic within cells for a healthy brain. Here, we provide an overview of such diseases, with a specific focus on proteins that directly or indirectly impact lipid transport.
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Affiliation(s)
- Andrés Guillén-Samander
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06520, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland 20815, USA
| | - Pietro De Camilli
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06520, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland 20815, USA
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8
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Dixon RE, Trimmer JS. Endoplasmic Reticulum-Plasma Membrane Junctions as Sites of Depolarization-Induced Ca 2+ Signaling in Excitable Cells. Annu Rev Physiol 2023; 85:217-243. [PMID: 36202100 PMCID: PMC9918718 DOI: 10.1146/annurev-physiol-032122-104610] [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] [Indexed: 11/09/2022]
Abstract
Membrane contact sites between endoplasmic reticulum (ER) and plasma membrane (PM), or ER-PM junctions, are found in all eukaryotic cells. In excitable cells they play unique roles in organizing diverse forms of Ca2+ signaling as triggered by membrane depolarization. ER-PM junctions underlie crucial physiological processes such as excitation-contraction coupling, smooth muscle contraction and relaxation, and various forms of activity-dependent signaling and plasticity in neurons. In many cases the structure and molecular composition of ER-PM junctions in excitable cells comprise important regulatory feedback loops linking depolarization-induced Ca2+ signaling at these sites to the regulation of membrane potential. Here, we describe recent findings on physiological roles and molecular composition of native ER-PM junctions in excitable cells. We focus on recent studies that provide new insights into canonical forms of depolarization-induced Ca2+ signaling occurring at junctional triads and dyads of striated muscle, as well as the diversity of ER-PM junctions in these cells and in smooth muscle and neurons.
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Affiliation(s)
- Rose E Dixon
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
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9
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Fan C, Chen K, Wang Y, Ball EV, Stenson PD, Mort M, Bacolla A, Kehrer-Sawatzki H, Tainer JA, Cooper DN, Zhao H. Profiling human pathogenic repeat expansion regions by synergistic and multi-level impacts on molecular connections. Hum Genet 2023; 142:245-274. [PMID: 36344696 PMCID: PMC10290229 DOI: 10.1007/s00439-022-02500-6] [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: 08/02/2022] [Accepted: 10/24/2022] [Indexed: 11/09/2022]
Abstract
Whilst DNA repeat expansions cause numerous heritable human disorders, their origins and underlying pathological mechanisms are often unclear. We collated a dataset comprising 224 human repeat expansions encompassing 203 different genes, and performed a systematic analysis with respect to key topological features at the DNA, RNA and protein levels. Comparison with controls without known pathogenicity and genomic regions lacking repeats, allowed the construction of the first tool to discriminate repeat regions harboring pathogenic repeat expansions (DPREx). At the DNA level, pathogenic repeat expansions exhibited stronger signals for DNA regulatory factors (e.g. H3K4me3, transcription factor-binding sites) in exons, promoters, 5'UTRs and 5'genes but were not significantly different from controls in introns, 3'UTRs and 3'genes. Additionally, pathogenic repeat expansions were also found to be enriched in non-B DNA structures. At the RNA level, pathogenic repeat expansions were characterized by lower free energy for forming RNA secondary structure and were closer to splice sites in introns, exons, promoters and 5'genes than controls. At the protein level, pathogenic repeat expansions exhibited a preference to form coil rather than other types of secondary structure, and tended to encode surface-located protein domains. Guided by these features, DPREx ( http://biomed.nscc-gz.cn/zhaolab/geneprediction/# ) achieved an Area Under the Curve (AUC) value of 0.88 in a test on an independent dataset. Pathogenic repeat expansions are thus located such that they exert a synergistic influence on the gene expression pathway involving inter-molecular connections at the DNA, RNA and protein levels.
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Affiliation(s)
- Cong Fan
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang West Road, Guangzhou, 500001, People's Republic of China
| | - Ken Chen
- School of Computer Science and Engineering, Sun Yat-Sen University, Guangzhou, 500001, China
| | - Yukai Wang
- School of Life Science, Sun Yat-Sen University, Guangzhou, 500001, China
| | - Edward V Ball
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Peter D Stenson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Matthew Mort
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | | | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Huiying Zhao
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang West Road, Guangzhou, 500001, People's Republic of China.
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10
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Steel D, Vezyroglou A, Barwick K, Smith M, Vogt J, Gibbon FM, Cross JH, Kurian MA. Both Heterozygous and Homozygous Loss-of-Function JPH3 Variants Are Associated with a Paroxysmal Movement Disorder. Mov Disord 2023; 38:155-157. [PMID: 36273396 PMCID: PMC10092631 DOI: 10.1002/mds.29250] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/09/2022] [Accepted: 08/29/2022] [Indexed: 01/25/2023] Open
Affiliation(s)
- Dora Steel
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
| | - Aikaterini Vezyroglou
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
| | - Katy Barwick
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Martin Smith
- Department of Paediatric Neurology, Oxford University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women and Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Frances M Gibbon
- Noah's Ark Children's Hospital for Wales, Cardiff and Vale University Health Board, Cardiff, Wales, United Kingdom
| | - J Helen Cross
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
| | - Manju A Kurian
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
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11
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Ruscitti F, Origone P, Rosti G, Trevisan L, Marchese R, Brugnolo A, Massa F, Castellini P, Mandich P. A case of Huntington disease-like 2 in a patient of African ancestry: the everlasting support of clinical examination in the molecular era. Clin Case Rep 2022; 10:e6308. [PMID: 36237940 PMCID: PMC9536496 DOI: 10.1002/ccr3.6308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/07/2022] Open
Abstract
Chorea, cognitive decline, and psychiatric symptoms are shared by Huntington’s disease (HD) and similar conditions called HD phenocopies. We describe the first case reported in Italy of Huntington disease‐like 2 (HDL2), clinically and radiologically indistinguishable from HD, showing the importance of considering African ancestry in the diagnostic process.
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Affiliation(s)
- Federica Ruscitti
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly,IRCCS Ospedale Policlinico San Martino, Medical Genetics UnitGenoaItaly
| | - Paola Origone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly,IRCCS Ospedale Policlinico San Martino, Medical Genetics UnitGenoaItaly
| | - Giulia Rosti
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly,IRCCS Ospedale Policlinico San Martino, Medical Genetics UnitGenoaItaly
| | - Lucia Trevisan
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly,IRCCS Ospedale Policlinico San Martino, Medical Genetics UnitGenoaItaly
| | - Roberta Marchese
- IRCCS Ospedale Policlinico San Martino, Neurological UnitGenoaItaly
| | - Andrea Brugnolo
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly,IRCCS Ospedale Policlinico San Martino, Clinical Psychology UnitGenoaItaly
| | - Federico Massa
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly
| | - Paola Castellini
- IRCCS Ospedale Policlinico San Martino, Phoniatric UnitGenoaItaly
| | - Paola Mandich
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI)University of GenoaGenoaItaly,IRCCS Ospedale Policlinico San Martino, Medical Genetics UnitGenoaItaly
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12
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A partnership between the lipid scramblase XK and the lipid transfer protein VPS13A at the plasma membrane. Proc Natl Acad Sci U S A 2022; 119:e2205425119. [PMID: 35994651 PMCID: PMC9436381 DOI: 10.1073/pnas.2205425119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chorea-acanthocytosis (ChAc) and McLeod syndrome are diseases with shared clinical manifestations caused by mutations in VPS13A and XK, respectively. Key features of these conditions are the degeneration of caudate neurons and the presence of abnormally shaped erythrocytes. XK belongs to a family of plasma membrane (PM) lipid scramblases whose action results in exposure of PtdSer at the cell surface. VPS13A is an endoplasmic reticulum (ER)-anchored lipid transfer protein with a putative role in the transport of lipids at contacts of the ER with other membranes. Recently VPS13A and XK were reported to interact by still unknown mechanisms. So far, however, there is no evidence for a colocalization of the two proteins at contacts of the ER with the PM, where XK resides, as VPS13A was shown to be localized at contacts between the ER and either mitochondria or lipid droplets. Here we show that VPS13A can also localize at ER-PM contacts via the binding of its PH domain to a cytosolic loop of XK, that such interaction is regulated by an intramolecular interaction within XK, and that both VPS13A and XK are highly expressed in the caudate neurons. Binding of the PH domain of VPS13A to XK is competitive with its binding to intracellular membranes that mediate other tethering functions of VPS13A. Our findings support a model according to which VPS13A-dependent lipid transfer between the ER and the PM is coupled to lipid scrambling within the PM. They raise the possibility that defective cell surface exposure of PtdSer may be responsible for neurodegeneration.
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13
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Zhang S, Shen L, Jiao B. Cognitive Dysfunction in Repeat Expansion Diseases: A Review. Front Aging Neurosci 2022; 14:841711. [PMID: 35478698 PMCID: PMC9036481 DOI: 10.3389/fnagi.2022.841711] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
With the development of the sequencing technique, more than 40 repeat expansion diseases (REDs) have been identified during the past two decades. Moreover, the clinical features of these diseases show some commonality, and the nervous system, especially the cognitive function was affected in part by these diseases. However, the specific cognitive domains impaired in different diseases were inconsistent. Here, we survey literature on the cognitive consequences of the following disorders presenting cognitive dysfunction and summarizing the pathogenic genes, epidemiology, and different domains affected by these diseases. We found that the cognitive domains affected in neuronal intranuclear inclusion disease (NIID) were widespread including the executive function, memory, information processing speed, attention, visuospatial function, and language. Patients with C9ORF72-frontotemporal dementia (FTD) showed impairment in executive function, memory, language, and visuospatial function. While in Huntington's disease (HD), the executive function, memory, and information processing speed were affected, in the fragile X-associated tremor/ataxia syndrome (FXTAS), executive function, memory, information processing speed, and attention were impaired. Moreover, the spinocerebellar ataxias showed broad damage in almost all the cognitive domains except for the relatively intact language ability. Some other diseases with relatively rare clinical data also indicated cognitive dysfunction, such as myotonic dystrophy type 1 (DM1), progressive myoclonus epilepsy (PME), Friedreich ataxia (FRDA), Huntington disease like-2 (HDL2), and cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS). We drew a cognitive function landscape of the related REDs that might provide an aspect for differential diagnosis through cognitive domains and effective non-specific interventions for these diseases.
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Affiliation(s)
- Sizhe Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, China
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Bin Jiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, China
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- *Correspondence: Bin Jiao
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14
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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15
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Loureiro JR, Castro AF, Figueiredo AS, Silveira I. Molecular Mechanisms in Pentanucleotide Repeat Diseases. Cells 2022; 11:cells11020205. [PMID: 35053321 PMCID: PMC8773600 DOI: 10.3390/cells11020205] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 02/01/2023] Open
Abstract
The number of neurodegenerative diseases resulting from repeat expansion has increased extraordinarily in recent years. In several of these pathologies, the repeat can be transcribed in RNA from both DNA strands producing, at least, one toxic RNA repeat that causes neurodegeneration by a complex mechanism. Recently, seven diseases have been found caused by a novel intronic pentanucleotide repeat in distinct genes encoding proteins highly expressed in the cerebellum. These disorders are clinically heterogeneous being characterized by impaired motor function, resulting from ataxia or epilepsy. The role that apparently normal proteins from these mutant genes play in these pathologies is not known. However, recent advances in previously known spinocerebellar ataxias originated by abnormal non-coding pentanucleotide repeats point to a gain of a toxic function by the pathogenic repeat-containing RNA that abnormally forms nuclear foci with RNA-binding proteins. In cells, RNA foci have been shown to be formed by phase separation. Moreover, the field of repeat expansions has lately achieved an extraordinary progress with the discovery that RNA repeats, polyglutamine, and polyalanine proteins are crucial for the formation of nuclear membraneless organelles by phase separation, which is perturbed when they are expanded. This review will cover the amazing advances on repeat diseases.
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Affiliation(s)
- Joana R. Loureiro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana F. Castro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Ana S. Figueiredo
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Isabel Silveira
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Correspondence: ; Tel.: +351-2240-8800
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16
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Gall-Duncan T, Sato N, Yuen RKC, Pearson CE. Advancing genomic technologies and clinical awareness accelerates discovery of disease-associated tandem repeat sequences. Genome Res 2022; 32:1-27. [PMID: 34965938 PMCID: PMC8744678 DOI: 10.1101/gr.269530.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/29/2021] [Indexed: 11/25/2022]
Abstract
Expansions of gene-specific DNA tandem repeats (TRs), first described in 1991 as a disease-causing mutation in humans, are now known to cause >60 phenotypes, not just disease, and not only in humans. TRs are a common form of genetic variation with biological consequences, observed, so far, in humans, dogs, plants, oysters, and yeast. Repeat diseases show atypical clinical features, genetic anticipation, and multiple and partially penetrant phenotypes among family members. Discovery of disease-causing repeat expansion loci accelerated through technological advances in DNA sequencing and computational analyses. Between 2019 and 2021, 17 new disease-causing TR expansions were reported, totaling 63 TR loci (>69 diseases), with a likelihood of more discoveries, and in more organisms. Recent and historical lessons reveal that properly assessed clinical presentations, coupled with genetic and biological awareness, can guide discovery of disease-causing unstable TRs. We highlight critical but underrecognized aspects of TR mutations. Repeat motifs may not be present in current reference genomes but will be in forthcoming gapless long-read references. Repeat motif size can be a single nucleotide to kilobases/unit. At a given locus, repeat motif sequence purity can vary with consequence. Pathogenic repeats can be "insertions" within nonpathogenic TRs. Expansions, contractions, and somatic length variations of TRs can have clinical/biological consequences. TR instabilities occur in humans and other organisms. TRs can be epigenetically modified and/or chromosomal fragile sites. We discuss the expanding field of disease-associated TR instabilities, highlighting prospects, clinical and genetic clues, tools, and challenges for further discoveries of disease-causing TR instabilities and understanding their biological and pathological impacts-a vista that is about to expand.
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Affiliation(s)
- Terence Gall-Duncan
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nozomu Sato
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
| | - Ryan K C Yuen
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Christopher E Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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17
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The molecular pathogenesis of repeat expansion diseases. Biochem Soc Trans 2021; 50:119-134. [PMID: 34940797 DOI: 10.1042/bst20200143] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 12/28/2022]
Abstract
Expanded short tandem repeats in the genome cause various monogenic diseases, particularly neurological disorders. Since the discovery of a CGG repeat expansion in the FMR1 gene in 1991, more than 40 repeat expansion diseases have been identified to date. In the coding repeat expansion diseases, in which the expanded repeat sequence is located in the coding regions of genes, the toxicity of repeat polypeptides, particularly misfolding and aggregation of proteins containing an expanded polyglutamine tract, have been the focus of investigation. On the other hand, in the non-coding repeat expansion diseases, in which the expanded repeat sequence is located in introns or untranslated regions, the toxicity of repeat RNAs has been the focus of investigation. Recently, these repeat RNAs were demonstrated to be translated into repeat polypeptides by the novel mechanism of repeat-associated non-AUG translation, which has extended the research direction of the pathological mechanisms of this disease entity to include polypeptide toxicity. Thus, a common pathogenesis has been suggested for both coding and non-coding repeat expansion diseases. In this review, we briefly outline the major pathogenic mechanisms of repeat expansion diseases, including a loss-of-function mechanism caused by repeat expansion, repeat RNA toxicity caused by RNA foci formation and protein sequestration, and toxicity by repeat polypeptides. We also discuss perturbation of the physiological liquid-liquid phase separation state caused by these repeat RNAs and repeat polypeptides, as well as potential therapeutic approaches against repeat expansion diseases.
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18
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Piggott CA, Jin Y. Junctophilins: Key Membrane Tethers in Muscles and Neurons. Front Mol Neurosci 2021; 14:709390. [PMID: 34305529 PMCID: PMC8295595 DOI: 10.3389/fnmol.2021.709390] [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: 05/13/2021] [Accepted: 06/15/2021] [Indexed: 12/26/2022] Open
Abstract
Contacts between the endoplasmic reticulum (ER) and plasma membrane (PM) contain specialized tethering proteins that bind both ER and PM membranes. In excitable cells, ER–PM contacts play an important role in calcium signaling and transferring lipids. Junctophilins are a conserved family of ER–PM tethering proteins. They are predominantly expressed in muscles and neurons and known to simultaneously bind both ER- and PM-localized ion channels. Since their discovery two decades ago, functional studies using junctophilin-deficient animals have provided a deep understanding of their roles in muscles and neurons, including excitation-contraction coupling, store-operated calcium entry (SOCE), and afterhyperpolarization (AHP). In this review, we highlight key findings from mouse, fly, and worm that support evolutionary conservation of junctophilins.
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Affiliation(s)
- Christopher A Piggott
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
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19
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Chintalaphani SR, Pineda SS, Deveson IW, Kumar KR. An update on the neurological short tandem repeat expansion disorders and the emergence of long-read sequencing diagnostics. Acta Neuropathol Commun 2021; 9:98. [PMID: 34034831 PMCID: PMC8145836 DOI: 10.1186/s40478-021-01201-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/17/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Short tandem repeat (STR) expansion disorders are an important cause of human neurological disease. They have an established role in more than 40 different phenotypes including the myotonic dystrophies, Fragile X syndrome, Huntington's disease, the hereditary cerebellar ataxias, amyotrophic lateral sclerosis and frontotemporal dementia. MAIN BODY STR expansions are difficult to detect and may explain unsolved diseases, as highlighted by recent findings including: the discovery of a biallelic intronic 'AAGGG' repeat in RFC1 as the cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS); and the finding of 'CGG' repeat expansions in NOTCH2NLC as the cause of neuronal intranuclear inclusion disease and a range of clinical phenotypes. However, established laboratory techniques for diagnosis of repeat expansions (repeat-primed PCR and Southern blot) are cumbersome, low-throughput and poorly suited to parallel analysis of multiple gene regions. While next generation sequencing (NGS) has been increasingly used, established short-read NGS platforms (e.g., Illumina) are unable to genotype large and/or complex repeat expansions. Long-read sequencing platforms recently developed by Oxford Nanopore Technology and Pacific Biosciences promise to overcome these limitations to deliver enhanced diagnosis of repeat expansion disorders in a rapid and cost-effective fashion. CONCLUSION We anticipate that long-read sequencing will rapidly transform the detection of short tandem repeat expansion disorders for both clinical diagnosis and gene discovery.
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Affiliation(s)
- Sanjog R. Chintalaphani
- School of Medicine, University of New South Wales, Sydney, 2052 Australia
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
| | - Sandy S. Pineda
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
- Brain and Mind Centre, University of Sydney, Camperdown, NSW 2050 Australia
| | - Ira W. Deveson
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
- Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Sydney, NSW 2010 Australia
| | - Kishore R. Kumar
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
- Molecular Medicine Laboratory and Neurology Department, Central Clinical School, Concord Repatriation General Hospital, University of Sydney, Concord, NSW 2137 Australia
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20
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Zhao B, Shan Y, Yang Y, Yu Z, Li T, Wang X, Luo T, Zhu Z, Sullivan P, Zhao H, Li Y, Zhu H. Transcriptome-wide association analysis of brain structures yields insights into pleiotropy with complex neuropsychiatric traits. Nat Commun 2021; 12:2878. [PMID: 34001886 PMCID: PMC8128893 DOI: 10.1038/s41467-021-23130-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/16/2021] [Indexed: 02/03/2023] Open
Abstract
Structural variations of the human brain are heritable and highly polygenic traits, with hundreds of associated genes identified in recent genome-wide association studies (GWAS). Transcriptome-wide association studies (TWAS) can both prioritize these GWAS findings and also identify additional gene-trait associations. Here we perform cross-tissue TWAS analysis of 211 structural neuroimaging and discover 278 associated genes exceeding Bonferroni significance threshold of 1.04 × 10-8. The TWAS-significant genes for brain structures have been linked to a wide range of complex traits in different domains. Through TWAS gene-based polygenic risk scores (PRS) prediction, we find that TWAS PRS gains substantial power in association analysis compared to conventional variant-based GWAS PRS, and up to 6.97% of phenotypic variance (p-value = 7.56 × 10-31) can be explained in independent testing data sets. In conclusion, our study illustrates that TWAS can be a powerful supplement to traditional GWAS in imaging genetics studies for gene discovery-validation, genetic co-architecture analysis, and polygenic risk prediction.
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Affiliation(s)
- Bingxin Zhao
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yue Shan
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yue Yang
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhaolong Yu
- Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
| | - Tengfei Li
- Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Xifeng Wang
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tianyou Luo
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ziliang Zhu
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Patrick Sullivan
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Hongyu Zhao
- Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
- Department of Biostatistics, Yale University, New Haven, CT, USA
| | - Yun Li
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Hongtu Zhu
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Biomedical Research Imaging Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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21
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Allelic and phenotypic heterogeneity in Junctophillin-3 related neurodevelopmental and movement disorders. Eur J Hum Genet 2021; 29:1027-1031. [PMID: 33824468 PMCID: PMC8187377 DOI: 10.1038/s41431-021-00866-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 02/22/2021] [Accepted: 03/10/2021] [Indexed: 12/28/2022] Open
Abstract
Junctophilin-3 belongs to a triprotein junctional complex implicated in the regulation of neuronal excitability and involved in the formation of junctional membrane structures between voltage-gated ion channels and endoplasmic (ryanodine) reticular receptors. A monoallelic trinucleotide repeat expansion located within the junctophilin-3 gene (JPH3) has been implicated in a rare autosomal dominant (AD) late-onset (and progressive) disorder clinically resembling Huntington disease (HD), and known as HD-like 2 (HDL2; MIM# 606438). Although the exact molecular mechanisms underlying HDL2 has not yet been fully elucidated, toxic gain-of-function of the aberrant transcript (containing the trinucleotide repeat) and loss of expression of (full-length) junctophilin-3 have both been implicated in HDL2 pathophysiology. In this study, we identified by whole exome sequencing (WES) a JPH3 homozygous truncating variant [NM_020655.4: c.17405dup; p.(Val581Argfs*137)]. in a female individual affected with genetically undetermined neurodevelopmental anomalies (including delayed motor milestones, abnormal social communication, language difficulties and borderline cognitive impairment) and paroxysmal attacks of dystonia since her early infancy. Our study expands the JPH3-associated mutational spectrum and clinical phenotypes, implicating the loss of Junctophilin-3 in heterogeneous neurodevelopmental phenotypes and early-onset paroxysmal movement disorders.
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22
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Mechanisms of repeat-associated non-AUG translation in neurological microsatellite expansion disorders. Biochem Soc Trans 2021; 49:775-792. [PMID: 33729487 PMCID: PMC8106499 DOI: 10.1042/bst20200690] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 02/08/2023]
Abstract
Repeat-associated non-AUG (RAN) translation was discovered in 2011 in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1). This non-canonical form of translation occurs in all reading frames from both coding and non-coding regions of sense and antisense transcripts carrying expansions of trinucleotide to hexanucleotide repeat sequences. RAN translation has since been reported in 7 of the 53 known microsatellite expansion disorders which mainly present with neurodegenerative features. RAN translation leads to the biosynthesis of low-complexity polymeric repeat proteins with aggregating and cytotoxic properties. However, the molecular mechanisms and protein factors involved in assembling functional ribosomes in absence of canonical AUG start codons remain poorly characterised while secondary repeat RNA structures play key roles in initiating RAN translation. Here, we briefly review the repeat expansion disorders, their complex pathogenesis and the mechanisms of physiological translation initiation together with the known factors involved in RAN translation. Finally, we discuss research challenges surrounding the understanding of pathogenesis and future directions that may provide opportunities for the development of novel therapeutic approaches for this group of incurable neurodegenerative diseases.
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23
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Hewlett B, Singh NP, Vannier C, Galli T. ER-PM Contact Sites - SNARING Actors in Emerging Functions. Front Cell Dev Biol 2021; 9:635518. [PMID: 33681218 PMCID: PMC7928305 DOI: 10.3389/fcell.2021.635518] [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: 11/30/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
The compartmentalisation achieved by confining cytoplasm into membrane-enclosed organelles in eukaryotic cells is essential for maintaining vital functions including ATP production, synthetic and degradative pathways. While intracellular organelles are highly specialised in these functions, the restricting membranes also impede exchange of molecules responsible for the synchronised and responsive cellular activities. The initial identification of contact sites between the ER and plasma membrane (PM) provided a potential candidate structure for communication between organelles without mixing by fusion. Over the past decades, research has revealed a far broader picture of the events. Membrane contact sites (MCSs) have been recognized as increasingly important actors in cell differentiation, plasticity and maintenance, and, upon dysfunction, responsible for pathological conditions such as cancer and neurodegenerative diseases. Present in multiple organelles and cell types, MCSs promote transport of lipids and Ca2+ homoeostasis, with a range of associated protein families. Interestingly, each MCS displays a unique molecular signature, adapted to organelle functions. This review will explore the literature describing the molecular components and interactions taking place at ER-PM contact sites, their functions, and implications in eukaryotic cells, particularly neurons, with emphasis on lipid transfer proteins and emerging function of SNAREs.
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Affiliation(s)
- Bailey Hewlett
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Neha Pratap Singh
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Christian Vannier
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Thierry Galli
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,GHU PARIS Psychiatrie and Neurosciences, Paris, France
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24
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Monckton DG. The Contribution of Somatic Expansion of the CAG Repeat to Symptomatic Development in Huntington's Disease: A Historical Perspective. J Huntingtons Dis 2021; 10:7-33. [PMID: 33579863 PMCID: PMC7990401 DOI: 10.3233/jhd-200429] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery in the early 1990s of the expansion of unstable simple sequence repeats as the causative mutation for a number of inherited human disorders, including Huntington’s disease (HD), opened up a new era of human genetics and provided explanations for some old problems. In particular, an inverse association between the number of repeats inherited and age at onset, and unprecedented levels of germline instability, biased toward further expansion, provided an explanation for the wide symptomatic variability and anticipation observed in HD and many of these disorders. The repeats were also revealed to be somatically unstable in a process that is expansion-biased, age-dependent and tissue-specific, features that are now increasingly recognised as contributory to the age-dependence, progressive nature and tissue specificity of the symptoms of HD, and at least some related disorders. With much of the data deriving from affected individuals, and model systems, somatic expansions have been revealed to arise in a cell division-independent manner in critical target tissues via a mechanism involving key components of the DNA mismatch repair pathway. These insights have opened new approaches to thinking about how the disease could be treated by suppressing somatic expansion and revealed novel protein targets for intervention. Exciting times lie ahead in turning these insights into novel therapies for HD and related disorders.
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Affiliation(s)
- Darren G Monckton
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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25
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Antisense Transcription across Nucleotide Repeat Expansions in Neurodegenerative and Neuromuscular Diseases: Progress and Mysteries. Genes (Basel) 2020; 11:genes11121418. [PMID: 33261024 PMCID: PMC7760973 DOI: 10.3390/genes11121418] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Unstable repeat expansions and insertions cause more than 30 neurodegenerative and neuromuscular diseases. Remarkably, bidirectional transcription of repeat expansions has been identified in at least 14 of these diseases. More remarkably, a growing number of studies has been showing that both sense and antisense repeat RNAs are able to dysregulate important cellular pathways, contributing together to the observed clinical phenotype. Notably, antisense repeat RNAs from spinocerebellar ataxia type 7, myotonic dystrophy type 1, Huntington's disease and frontotemporal dementia/amyotrophic lateral sclerosis associated genes have been implicated in transcriptional regulation of sense gene expression, acting either at a transcriptional or posttranscriptional level. The recent evidence that antisense repeat RNAs could modulate gene expression broadens our understanding of the pathogenic pathways and adds more complexity to the development of therapeutic strategies for these disorders. In this review, we cover the amazing progress made in the understanding of the pathogenic mechanisms associated with repeat expansion neurodegenerative and neuromuscular diseases with a focus on the impact of antisense repeat transcription in the development of efficient therapies.
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26
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zakeri M, babaei AH, akbari MT, zare S, khordadpoor F. Prevalence of Trinucleotide Expansions in SCA17/TBP and JPH3 Genes and Octapeptide Insertion in PRNP Gene in Iranian Patients with Huntington-Disease like Syndrome. MEDICAL LABORATORY JOURNAL 2020. [DOI: 10.29252/mlj.14.5.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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27
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Khristich AN, Mirkin SM. On the wrong DNA track: Molecular mechanisms of repeat-mediated genome instability. J Biol Chem 2020; 295:4134-4170. [PMID: 32060097 PMCID: PMC7105313 DOI: 10.1074/jbc.rev119.007678] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Expansions of simple tandem repeats are responsible for almost 50 human diseases, the majority of which are severe, degenerative, and not currently treatable or preventable. In this review, we first describe the molecular mechanisms of repeat-induced toxicity, which is the connecting link between repeat expansions and pathology. We then survey alternative DNA structures that are formed by expandable repeats and review the evidence that formation of these structures is at the core of repeat instability. Next, we describe the consequences of the presence of long structure-forming repeats at the molecular level: somatic and intergenerational instability, fragility, and repeat-induced mutagenesis. We discuss the reasons for gender bias in intergenerational repeat instability and the tissue specificity of somatic repeat instability. We also review the known pathways in which DNA replication, transcription, DNA repair, and chromatin state interact and thereby promote repeat instability. We then discuss possible reasons for the persistence of disease-causing DNA repeats in the genome. We describe evidence suggesting that these repeats are a payoff for the advantages of having abundant simple-sequence repeats for eukaryotic genome function and evolvability. Finally, we discuss two unresolved fundamental questions: (i) why does repeat behavior differ between model systems and human pedigrees, and (ii) can we use current knowledge on repeat instability mechanisms to cure repeat expansion diseases?
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Affiliation(s)
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, Massachusetts 02155.
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28
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Huntington disease like 2 (HDL-2) with parkinsonism and abnormal DAT-SPECT – A novel observation. Parkinsonism Relat Disord 2020; 71:46-48. [DOI: 10.1016/j.parkreldis.2020.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 11/24/2022]
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29
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Öztürk Z, O’Kane CJ, Pérez-Moreno JJ. Axonal Endoplasmic Reticulum Dynamics and Its Roles in Neurodegeneration. Front Neurosci 2020; 14:48. [PMID: 32116502 PMCID: PMC7025499 DOI: 10.3389/fnins.2020.00048] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
The physical continuity of axons over long cellular distances poses challenges for their maintenance. One organelle that faces this challenge is endoplasmic reticulum (ER); unlike other intracellular organelles, this forms a physically continuous network throughout the cell, with a single membrane and a single lumen. In axons, ER is mainly smooth, forming a tubular network with occasional sheets or cisternae and low amounts of rough ER. It has many potential roles: lipid biosynthesis, glucose homeostasis, a Ca2+ store, protein export, and contacting and regulating other organelles. This tubular network structure is determined by ER-shaping proteins, mutations in some of which are causative for neurodegenerative disorders such as hereditary spastic paraplegia (HSP). While axonal ER shares many features with the tubular ER network in other contexts, these features must be adapted to the long and narrow dimensions of axons. ER appears to be physically continuous throughout axons, over distances that are enormous on a subcellular scale. It is therefore a potential channel for long-distance or regional communication within neurons, independent of action potentials or physical transport of cargos, but involving its physiological roles such as Ca2+ or organelle homeostasis. Despite its apparent stability, axonal ER is highly dynamic, showing features like anterograde and retrograde transport, potentially reflecting continuous fusion and breakage of the network. Here we discuss the transport processes that must contribute to this dynamic behavior of ER. We also discuss the model that these processes underpin a homeostatic process that ensures both enough ER to maintain continuity of the network and repair breaks in it, but not too much ER that might disrupt local cellular physiology. Finally, we discuss how failure of ER organization in axons could lead to axon degenerative diseases, and how a requirement for ER continuity could make distal axons most susceptible to degeneration in conditions that disrupt ER continuity.
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Affiliation(s)
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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30
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Ferreira-Correia A, Anderson DG, Cockcroft K, Krause A. The neuropsychological deficits and dissociations in Huntington Disease-Like 2: A series of case-control studies. Neuropsychologia 2020; 136:107238. [DOI: 10.1016/j.neuropsychologia.2019.107238] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/23/2019] [Accepted: 10/25/2019] [Indexed: 01/01/2023]
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31
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Sznajder ŁJ, Swanson MS. Short Tandem Repeat Expansions and RNA-Mediated Pathogenesis in Myotonic Dystrophy. Int J Mol Sci 2019; 20:ijms20133365. [PMID: 31323950 PMCID: PMC6651174 DOI: 10.3390/ijms20133365] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/27/2019] [Accepted: 07/08/2019] [Indexed: 12/23/2022] Open
Abstract
Short tandem repeat (STR) or microsatellite, expansions underlie more than 50 hereditary neurological, neuromuscular and other diseases, including myotonic dystrophy types 1 (DM1) and 2 (DM2). Current disease models for DM1 and DM2 propose a common pathomechanism, whereby the transcription of mutant DMPK (DM1) and CNBP (DM2) genes results in the synthesis of CUG and CCUG repeat expansion (CUGexp, CCUGexp) RNAs, respectively. These CUGexp and CCUGexp RNAs are toxic since they promote the assembly of ribonucleoprotein (RNP) complexes or RNA foci, leading to sequestration of Muscleblind-like (MBNL) proteins in the nucleus and global dysregulation of the processing, localization and stability of MBNL target RNAs. STR expansion RNAs also form phase-separated gel-like droplets both in vitro and in transiently transfected cells, implicating RNA-RNA multivalent interactions as drivers of RNA foci formation. Importantly, the nucleation and growth of these nuclear foci and transcript misprocessing are reversible processes and thus amenable to therapeutic intervention. In this review, we provide an overview of potential DM1 and DM2 pathomechanisms, followed by a discussion of MBNL functions in RNA processing and how multivalent interactions between expanded STR RNAs and RNA-binding proteins (RBPs) promote RNA foci assembly.
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Affiliation(s)
- Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
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32
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Anderson DG, Ferreira-Correia A, Rodrigues FB, Aziz NA, Carr J, Wild EJ, Margolis RL, Krause A. Comparison of the Huntington's Disease like 2 and Huntington's Disease Clinical Phenotypes. Mov Disord Clin Pract 2019; 6:302-311. [PMID: 31061838 DOI: 10.1002/mdc3.12742] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/23/2019] [Accepted: 02/13/2019] [Indexed: 01/17/2023] Open
Abstract
Background Huntington's disease like 2 (HDL2) is the most common Huntington's disease (HD) phenocopy in many countries and described as the phenocopy with the greatest resemblance to HD. The current clinical description of HDL2 is based on retrospective data. It is unknown whether HDL2 has clinical features that distinguish it from HD. Objective To describe the HDL2 phenotype and compare it to HD systematically. Methods A blinded cross-sectional design was used to compare the HDL2 (n = 15) and HD (n = 13) phenotypes. African ancestry participants underwent assessments, including the Unified Huntington's Disease Rating Scale (UHDRS). The UHDRS motor component was video recorded and evaluated by blinded experts and the inter-rater reliability calculated. Results Both groups were homogeneous in terms of demographics and disease characteristics. However, HDL2 patients presented three years earlier with more prominent dysarthria and dystonia. Raters could not distinguish between the two diseases with a high level of agreement. No significant differences in the TMS between HDL2 and HD were found. In both disorders, disease duration correlated with motor scores, with the exception of chorea. Psychiatric and cognitive scores were not significantly different between the groups. Conclusions The HDL2 phenotype is similar to HD and is initially characterized by dementia, chorea, and oculomotor abnormalities, progressing to a rigid and bradykinetic state, suggesting the UHDRS is useful to monitor disease progression in HDL2. Although HDL2 patients scored higher on some UHDRS domains, this did not differentiate between the two diseases; it may however be emerging evidence of HDL2 having a more severe clinical phenotype.
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Affiliation(s)
- David G Anderson
- The University of the Witwatersrand Donald Gordon Medical Centre Neurology Johannesburg South Africa.,Division of Human Genetics National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand Johannesburg South Africa
| | - Aline Ferreira-Correia
- Department of Psychology School of Human and Community Development, University of the Witwatersrand. Johannesburg South Africa
| | - Filipe B Rodrigues
- UCL Huntington's Disease Centre University College London UK.,Clinical Pharmacology Unit Instituto de Medicina Molecular Portugal.,Laboratory of Clinical Pharmacology and Therapeutics University of Lisbon Portugal
| | - N Ahmad Aziz
- German Center for Neurodegenerative Diseases (DZNE) Bonn Germany
| | - Jonathan Carr
- Division of Neurology, Department of Medicine University of Stellenbosch Cape Town South Africa
| | - Edward J Wild
- UCL Huntington's Disease Centre University College London UK
| | - Russell L Margolis
- Departments of Psychiatry and Neurology, Program in Cellular and Molecular Medicine Johns Hopkins University School of Medicine Baltimore MD USA
| | - Amanda Krause
- Division of Human Genetics National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand Johannesburg South Africa
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33
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Jiang J, Tang M, Huang Z, Chen L. Junctophilins emerge as novel therapeutic targets. J Cell Physiol 2019; 234:16933-16943. [DOI: 10.1002/jcp.28405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Jinyong Jiang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Mingzhu Tang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Zhen Huang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
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34
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Anderson DG, Haagensen M, Ferreira-Correia A, Pierson R, Carr J, Krause A, Margolis RL. Emerging differences between Huntington's disease-like 2 and Huntington's disease: A comparison using MRI brain volumetry. Neuroimage Clin 2019; 21:101666. [PMID: 30682531 PMCID: PMC6350216 DOI: 10.1016/j.nicl.2019.101666] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/18/2018] [Accepted: 01/04/2019] [Indexed: 01/18/2023]
Abstract
Huntington's Disease-Like 2 (HDL2), caused by a CTG/CAG expansion in JPH3 on chromosome 16q24, is the most common Huntington's Disease (HD) phenocopy in populations with African ancestry. Qualitatively, brain MRIs of HDL2 patients have been indistinguishable from HD. To determine brain regions most affected in HDL2 a cross-sectional study using MRI brain volumetry was undertaken to compare the brains of nine HDL2, 11 HD and nine age matched control participants. Participants were ascertained from the region in South Africa with the world's highest HDL2 incidence. The HDL2 and HD patient groups showed no significant differences with respect to mean age at MRI, disease duration, abnormal triplet repeat length, or age at disease onset. Overall, intracerebral volumes were smaller in both affected groups compared to the control group. Comparing the HDL2 and HD groups across multiple covariates, cortical and subcortical volumes were similar with the exception that the HDL2 thalamic volumes were smaller. Consistent with other similarities between the two diseases, these results indicate a pattern of neurodegeneration in HDL2 that is remarkably similar to HD. However smaller thalamic volumes in HDL2 raises intriguing questions into the pathogenesis of both disorders, and how these volumetric differences relate to their respective phenotypes.
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Affiliation(s)
- David G Anderson
- The University of the Witwatersrand Donald Gordon Medical Centre, Neurology, Johannesburg, South Africa; Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand, Johannesburg, South Africa.
| | - Mark Haagensen
- The University of the Witwatersrand Donald Gordon Medical Centre, Radiology Department, Johannesburg, South Africa
| | - Aline Ferreira-Correia
- Department of Psychology, School of Human and Community Development, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Jonathan Carr
- Division of Neurology, Department of Medicine, University of Stellenbosch, Cape Town, South Africa
| | - Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, The University of the Witwatersrand, Johannesburg, South Africa
| | - Russell L Margolis
- Departments of Psychiatry and Neurology, Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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35
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Murmann AE, Yu J, Opal P, Peter ME. Trinucleotide Repeat Expansion Diseases, RNAi, and Cancer. Trends Cancer 2018; 4:684-700. [PMID: 30292352 DOI: 10.1016/j.trecan.2018.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/23/2018] [Accepted: 08/24/2018] [Indexed: 01/12/2023]
Abstract
Many neurodegenerative diseases are caused by unstable trinucleotide repeat (TNR) expansions located in disease-associated genes. siRNAs based on CAG repeat expansions effectively kill cancer cell lines in vitro through RNAi. They also cause significant reduction in tumor growth in a human ovarian cancer mouse model with no toxicity to the treated mice. This suggests that cancer cells are particularly sensitive to CAG TNR-derived siRNAs, and explains a reported inverse correlation between the length of CAG TNRs and reduced global cancer incidences in some CAG TNR diseases. This review discusses both mutant proteins and mutant RNAs as a cause of TNR diseases, with a focus on RNAi and its role in contributing to disease pathology and in suppressing cancer.
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Affiliation(s)
- Andrea E Murmann
- Department of Medicine, Division Hematology/Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jindan Yu
- Department of Medicine, Division Hematology/Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, IL 60611, USA
| | - Puneet Opal
- Davee Department of Neurology, Northwestern University, Chicago, IL 60611, USA
| | - Marcus E Peter
- Department of Medicine, Division Hematology/Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, IL 60611, USA.
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36
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Kumar N, Leonzino M, Hancock-Cerutti W, Horenkamp FA, Li P, Lees JA, Wheeler H, Reinisch KM, De Camilli P. VPS13A and VPS13C are lipid transport proteins differentially localized at ER contact sites. J Cell Biol 2018; 217:3625-3639. [PMID: 30093493 PMCID: PMC6168267 DOI: 10.1083/jcb.201807019] [Citation(s) in RCA: 344] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 01/07/2023] Open
Abstract
Structural and biochemical studies show that VPS13 family proteins are lipid transporters. VPS13A and VPS13C tether the ER to mitochondria and to endosomes/lysosomes, respectively, suggesting lipid dyshomeostasis as the cause of chorea acanthocytosis and Parkinson’s disease resulting from their mutations. Mutations in the human VPS13 genes are responsible for neurodevelopmental and neurodegenerative disorders including chorea acanthocytosis (VPS13A) and Parkinson’s disease (VPS13C). The mechanisms of these diseases are unknown. Genetic studies in yeast hinted that Vps13 may have a role in lipid exchange between organelles. In this study, we show that the N-terminal portion of VPS13 is tubular, with a hydrophobic cavity that can solubilize and transport glycerolipids between membranes. We also show that human VPS13A and VPS13C bind to the ER, tethering it to mitochondria (VPS13A), to late endosome/lysosomes (VPS13C), and to lipid droplets (both VPS13A and VPS13C). These findings identify VPS13 as a lipid transporter between the ER and other organelles, implicating defects in membrane lipid homeostasis in neurological disorders resulting from their mutations. Sequence and secondary structure similarity between the N-terminal portions of Vps13 and other proteins such as the autophagy protein ATG2 suggest lipid transport roles for these proteins as well.
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Affiliation(s)
- Nikit Kumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Marianna Leonzino
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
| | - William Hancock-Cerutti
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
| | - Florian A Horenkamp
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - PeiQi Li
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Joshua A Lees
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Heather Wheeler
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
| | - Karin M Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT .,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
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37
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Walker RH, Gatto EM, Bustamante ML, Bernal-Pacheco O, Cardoso F, Castilhos RM, Chana-Cuevas P, Cornejo-Olivas M, Estrada-Bellmann I, Jardim LB, López-Castellanos R, López-Contreras R, Maia DP, Mazzetti P, Miranda M, Rodríguez-Violante M, Teive H, Tumas V. Huntington's disease-like disorders in Latin America and the Caribbean. Parkinsonism Relat Disord 2018; 53:10-20. [PMID: 29853295 DOI: 10.1016/j.parkreldis.2018.05.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 04/24/2018] [Accepted: 05/18/2018] [Indexed: 12/11/2022]
Abstract
Diseases with a choreic phenotype can be due to a variety of genetic etiologies. As testing for Huntington's disease (HD) becomes more available in previously resource-limited regions, it is becoming apparent that there are patients in these areas with other rare genetic conditions which cause an HD-like phenotype. Documentation of the presence of these conditions is important in order to provide appropriate diagnostic and clinical care for these populations. Information for this article was gathered in two ways; the literature was surveyed for publications reporting a variety of genetic choreic disorders, and movement disorders specialists from countries in Latin America and the Caribbean were contacted regarding their experiences with chorea of genetic etiology. Here we discuss the availability of molecular diagnostics for HD and for other choreic disorders, along with a summary of the published reports of affected subjects, and authors' personal experiences from the regions. While rare, patients affected by non-HD genetic choreas are evidently present in Latin America and the Caribbean. HD-like 2 is particularly prevalent in countries where the population has African ancestry. The incidence of other conditions is likely determined by other variations in ethnic background and settlement patterns. As genetic resources and awareness of these disorders improve, more patients are likely to be identified, and have the potential to benefit from education, support, and ultimately molecular therapies.
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Affiliation(s)
- Ruth H Walker
- Department of Neurology, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA; Mount Sinai School of Medicine, New York, NY, USA.
| | - Emilia M Gatto
- Sanatorio Trinidad Mitre, INEBA, Buenos Aires, Argentina
| | - M Leonor Bustamante
- Human Genetics Program, Biomedical Sciences Institute, and Department of Psychiatry North Division, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | | | | | - Raphael M Castilhos
- Neurology Service, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil
| | - Pedro Chana-Cuevas
- Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Mario Cornejo-Olivas
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
| | | | - Laura B Jardim
- Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Brazil
| | - Ricardo López-Castellanos
- Department of Neurology and Rehabilitation Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - Debora P Maia
- The Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Pilar Mazzetti
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
| | - Marcelo Miranda
- Department of Neurology, Clinica Las Condes, Santiago, Chile
| | | | - Helio Teive
- Movement Disorders Unit, Neurology Service, Internal Medicine Department, Hospital de Clínicas, Federal University of Parana, Curitiba, Brazil
| | - Vitor Tumas
- Department of Neuroscience and Behavior Sciences, Ribeirao Preto School of Medicine, University of Sao Paulo, Ribeirao Preto, Brazil
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38
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Youssov K, Bachoud-Lévi AC. Malattia di Huntington: aspetti diagnostici attuali e applicazioni pratiche. Neurologia 2018. [DOI: 10.1016/s1634-7072(18)89403-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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39
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Calpena E, López Del Amo V, Chakraborty M, Llamusí B, Artero R, Espinós C, Galindo MI. The Drosophila junctophilin gene is functionally equivalent to its four mammalian counterparts and is a modifier of a Huntingtin poly-Q expansion and the Notch pathway. Dis Model Mech 2018; 11:dmm.029082. [PMID: 29208631 PMCID: PMC5818072 DOI: 10.1242/dmm.029082] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 11/08/2017] [Indexed: 12/13/2022] Open
Abstract
Members of the Junctophilin (JPH) protein family have emerged as key actors in all excitable cells, with crucial implications for human pathophysiology. In mammals, this family consists of four members (JPH1-JPH4) that are differentially expressed throughout excitable cells. The analysis of knockout mice lacking JPH subtypes has demonstrated their essential contribution to physiological functions in skeletal and cardiac muscles and in neurons. Moreover, mutations in the human JPH2 gene are associated with hypertrophic and dilated cardiomyopathies; mutations in JPH3 are responsible for the neurodegenerative Huntington's disease-like-2 (HDL2), whereas JPH1 acts as a genetic modifier in Charcot–Marie–Tooth 2K peripheral neuropathy. Drosophila melanogaster has a single junctophilin (jp) gene, as is the case in all invertebrates, which might retain equivalent functions of the four homologous JPH genes present in mammalian genomes. Therefore, owing to the lack of putatively redundant genes, a jpDrosophila model could provide an excellent platform to model the Junctophilin-related diseases, to discover the ancestral functions of the JPH proteins and to reveal new pathways. By up- and downregulation of Jp in a tissue-specific manner in Drosophila, we show that altering its levels of expression produces a phenotypic spectrum characterized by muscular deficits, dilated cardiomyopathy and neuronal alterations. Importantly, our study has demonstrated that Jp modifies the neuronal degeneration in a Drosophila model of Huntington's disease, and it has allowed us to uncover an unsuspected functional relationship with the Notch pathway. Therefore, this Drosophila model has revealed new aspects of Junctophilin function that can be relevant for the disease mechanisms of their human counterparts. Summary: This work reveals that the Drosophila Junctophilin protein has similar functions to its mammalian homologues and uncovers new interactions of potential biomedical interest with Huntingtin and Notch signalling.
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Affiliation(s)
- Eduardo Calpena
- Program in Molecular Mechanisms of Disease, Centro de Investigación Príncipe Felipe (CIPF), c/ Eduardo Primo Yúfera no. 3, 46012 Valencia, Spain
| | - Víctor López Del Amo
- Program in Molecular Mechanisms of Disease, Centro de Investigación Príncipe Felipe (CIPF), c/ Eduardo Primo Yúfera no. 3, 46012 Valencia, Spain
| | - Mouli Chakraborty
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain.,Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, c/ Dr Moliner 50, 46100 Burjasot, Spain
| | - Beatriz Llamusí
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain.,Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, c/ Dr Moliner 50, 46100 Burjasot, Spain
| | - Rubén Artero
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain.,Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, c/ Dr Moliner 50, 46100 Burjasot, Spain
| | - Carmen Espinós
- Program in Molecular Mechanisms of Disease, Centro de Investigación Príncipe Felipe (CIPF), c/ Eduardo Primo Yúfera no. 3, 46012 Valencia, Spain.,UPV-CIPF Joint Unit Disease Mechanisms and Nanomedicine, 46012 Valencia, Spain
| | - Máximo I Galindo
- Program in Molecular Mechanisms of Disease, Centro de Investigación Príncipe Felipe (CIPF), c/ Eduardo Primo Yúfera no. 3, 46012 Valencia, Spain .,UPV-CIPF Joint Unit Disease Mechanisms and Nanomedicine, 46012 Valencia, Spain.,Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, 46022 Valencia, Spain
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Pathogenic insights from Huntington's disease-like 2 and other Huntington's disease genocopies. Curr Opin Neurol 2018; 29:743-748. [PMID: 27749395 DOI: 10.1097/wco.0000000000000386] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE OF REVIEW Huntington's disease-like 2 (HDL2) is a rare, progressive, autosomal dominant neurodegenerative disorder that genetically, clinically, and pathologically closely resembles Huntington's disease. We review HDL2 pathogenic mechanisms and examine the implications of these mechanisms for Huntington's disease and related diseases. RECENT FINDINGS HDL2 is caused by a CTG/CAG repeat expansion in junctophilin-3. Available data from cell and animal models and human brain suggest that HDL2 is a complex disease in which transcripts and proteins expressed bidirectionally from the junctophilin-3 locus contribute to pathogenesis through both gain-and loss-of-function mechanisms. Recent advances indicate that the pathogenesis of Huntington's disease is equally complex, despite the emphasis on toxic gain-of-function properties of the mutant huntingtin protein. SUMMARY Studies examining in parallel the genetic, clinical, neuropathological, and mechanistic similarities between Huntington's disease and HDL2 have begun to identify points of convergence between the pathogenic pathways of the two diseases. Comparisons to other diseases that are phenotypically or genetically related to Huntington's disease and HDL2 will likely reveal additional common pathways. The ultimate goal is to identify shared therapeutic targets and eventually develop therapies that may, at least in part, be effective across multiple similar rare diseases, an essential approach given the scarcity of resources for basic and translational research.
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Ocampo C, Daimari R, Oyekunle AA. Huntington’s disease-like 2 with an expansion mutation of the Junctophilin-3 gene; first reported case from Botswana. J Clin Neurosci 2018; 47:126-127. [PMID: 29066237 DOI: 10.1016/j.jocn.2017.10.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 10/02/2017] [Indexed: 02/06/2023]
Affiliation(s)
- C Ocampo
- Department of Internal Medicine, University of Botswana and Princess Marina Hospital, Gaborone, Botswana
| | - R Daimari
- Department of Internal Medicine, University of Botswana and Princess Marina Hospital, Gaborone, Botswana
| | - A A Oyekunle
- Department of Internal Medicine, University of Botswana and Princess Marina Hospital, Gaborone, Botswana.
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Toyoshima Y, Takahashi H. Spinocerebellar Ataxia Type 17 (SCA17). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1049:219-231. [PMID: 29427105 DOI: 10.1007/978-3-319-71779-1_10] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In 1999, a polyglutamine expansion was identified in the transcription factor TATA-binding protein (TBP) in a patient with ataxia with negative family history. Subsequently, CAG/CAA repeat expansions in the TBP gene were identified in families with spinocerebellar ataxia (SCA), establishing this repeat expansion as the underlying mutation in SCA type 17 (SCA17). There are several characteristic differences between SCA17 and other polyglutamine diseases. First, SCA17 shows a complex and variable clinical phenotype, in some cases overlapping that of Huntington's disease. Second, compared to the other SCA subtypes caused by expanded trinucleotide repeats, anticipation in SCA17 kindreds is rare because of the characteristic structure of the TBP gene. And thirdly, SCA17 patients often have diagnostic problems that may arise from non-penetrance. Because the gap between normal and abnormal repeat numbers is very narrow, it is difficult to determine a cutoff value for pathologic CAG repeat number in SCA17. Herein, we review the clinical, genetic and pathologic features of SCA17.
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Affiliation(s)
- Yasuko Toyoshima
- Department of Pathology, Brain Research Institute, University of Niigata, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Japan.
| | - Hitoshi Takahashi
- Department of Pathology, Brain Research Institute, University of Niigata, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Japan
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Abstract
More than 40 diseases, most of which primarily affect the nervous system, are caused by expansions of simple sequence repeats dispersed throughout the human genome. Expanded trinucleotide repeat diseases were discovered first and remain the most frequent. More recently tetra-, penta-, hexa-, and even dodeca-nucleotide repeat expansions have been identified as the cause of human disease, including some of the most common genetic disorders seen by neurologists. Repeat expansion diseases include both causes of myotonic dystrophy (DM1 and DM2), the most common genetic cause of amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72), Huntington disease, and eight other polyglutamine disorders, including the most common forms of dominantly inherited ataxia, the most common recessive ataxia (Friedreich ataxia), and the most common heritable mental retardation (fragile X syndrome). Here I review distinctive features of this group of diseases that stem from the unusual, dynamic nature of the underlying mutations. These features include marked clinical heterogeneity and the phenomenon of clinical anticipation. I then discuss the diverse molecular mechanisms driving disease pathogenesis, which vary depending on the repeat sequence, size, and location within the disease gene, and whether the repeat is translated into protein. I conclude with a brief clinical and genetic description of individual repeat expansion diseases that are most relevant to neurologists.
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Anderson DG, Carmona S, Naidoo K, Coetzer TL, Carr J, Rudnicki DD, Walker RH, Margolis RL, Krause A. Absence of Acanthocytosis in Huntington's Disease-like 2: A Prospective Comparison with Huntington's Disease. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2017; 7:512. [PMID: 29226019 PMCID: PMC5721130 DOI: 10.7916/d81j9pdx] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 11/15/2017] [Indexed: 12/27/2022]
Abstract
Background Huntington’s Disease-like 2 (HDL2) is classified as a neuroacanthocytosis; however, this remains unverified. We aim to determine if acanthocytes are present in HDL2 and whether acanthocytes can differentiate HDL2 from Huntington’s disease (HD). Methods We prospectively compared 13 HD and 12 HDL2 cases against 21 unaffected controls in Johannesburg. Blood smears were prepared using international standards and reviewed by at least two blinded reviewers. An acanthocytosis rate of greater than 1.2% in the dry smear or greater than 3.7% in the wet smear was designated a priori as the threshold for clinical significance based on previously established standards. Flow cytometry was performed on all but four of the cases. Red cell membrane protein analysis was performed on all participants. Results There were 12 HDL2, 13 HD, and 21 controls enrolled. None of the HD or HDL2 participants had defined acanthocytosis or other morphological abnormalities. None of the HD or HDL2 cases had evidence of an abnormal band 3. Discussion Acanthocytosis was not identified in either HDL2 or HD in our patient population. Our results, based on the first prospective study of acanthocytes in HDL2 or HD, suggest that screening for acanthocytes will not help establish the diagnosis of HD or HDL2, nor differentiate between the two disorders and raises the question if HDL2 should be placed within the neuroacanthocytosis syndromes.
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Affiliation(s)
- David G Anderson
- Department of Neurology, The University of the Witwatersrand Donald Gordon Medical Center, Johannesburg, South Africa.,Division of Human Genetics, University of the Witwatersrand, Johannesburg, South Africa
| | - Sergio Carmona
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Kubendran Naidoo
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Theresa L Coetzer
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Jonathan Carr
- Department of Neurology, University of Stellenbosch, Cape Town, South Africa
| | - Dobrila D Rudnicki
- Office of Special Initiatives, National Center for Advancing Translational Sciences, NIH, Bethesda, MD, USA.,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ruth H Walker
- Department of Neurology, James J. Peters Veterans Affairs Medical Center, New York, NY, USA.,Department of Neurology, Mount Sinai School of Medicine, New York City, NY, USA
| | - Russell L Margolis
- Departments of Psychiatry and Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Amanda Krause
- Division of Human Genetics, University of the Witwatersrand, Johannesburg, South Africa.,Division of Human Genetics, National Health Laboratory Service, Johannesburg, South Africa
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Intrinsic Disorder in Proteins with Pathogenic Repeat Expansions. Molecules 2017; 22:molecules22122027. [PMID: 29186753 PMCID: PMC6149999 DOI: 10.3390/molecules22122027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.
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Abstract
Neurodegeneration is a leading cause of death in the developed world and a natural, albeit unfortunate, consequence of longer-lived populations. Despite great demand for therapeutic intervention, it is often the case that these diseases are insufficiently understood at the basic molecular level. What little is known has prompted much hopeful speculation about a generalized mechanistic thread that ties these disparate conditions together at the subcellular level and can be exploited for broad curative benefit. In this review, we discuss a prominent theory supported by genetic and pathological changes in an array of neurodegenerative diseases: that neurons are particularly vulnerable to disruption of RNA-binding protein dosage and dynamics. Here we synthesize the progress made at the clinical, genetic, and biophysical levels and conclude that this perspective offers the most parsimonious explanation for these mysterious diseases. Where appropriate, we highlight the reciprocal benefits of cross-disciplinary collaboration between disease specialists and RNA biologists as we envision a future in which neurodegeneration declines and our understanding of the broad importance of RNA processing deepens.
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Affiliation(s)
- Erin G Conlon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Rohilla KJ, Gagnon KT. RNA biology of disease-associated microsatellite repeat expansions. Acta Neuropathol Commun 2017; 5:63. [PMID: 28851463 PMCID: PMC5574247 DOI: 10.1186/s40478-017-0468-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/22/2017] [Indexed: 12/13/2022] Open
Abstract
Microsatellites, or simple tandem repeat sequences, occur naturally in the human genome and have important roles in genome evolution and function. However, the expansion of microsatellites is associated with over two dozen neurological diseases. A common denominator among the majority of these disorders is the expression of expanded tandem repeat-containing RNA, referred to as xtrRNA in this review, which can mediate molecular disease pathology in multiple ways. This review focuses on the potential impact that simple tandem repeat expansions can have on the biology and metabolism of RNA that contain them and underscores important gaps in understanding. Merging the molecular biology of repeat expansion disorders with the current understanding of RNA biology, including splicing, transcription, transport, turnover and translation, will help clarify mechanisms of disease and improve therapeutic development.
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RNA phase transitions in repeat expansion disorders. Nature 2017; 546:243-247. [PMID: 28562589 PMCID: PMC5555642 DOI: 10.1038/nature22386] [Citation(s) in RCA: 515] [Impact Index Per Article: 73.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/24/2017] [Indexed: 12/19/2022]
Abstract
Expansions of short nucleotide repeats produce several neurological and neuromuscular disorders including Huntington’s disease, muscular dystrophy and amyotrophic lateral sclerosis. A common pathological feature of these diseases is the accumulation of the repeat containing transcripts into aberrant foci in the nucleus. RNA foci, as well as the disease symptoms, only manifest above a critical number of nucleotide repeats, but the molecular mechanism governing foci formation above this characteristic threshold remains unresolved. Here, we show that repeat expansions create templates for multivalent base-pairing, which causes purified RNA to undergo a sol-gel transition at a similar critical repeat number as observed in the diseases. In cells, RNA foci form by phase separation of the repeat-containing RNA and can be dissolved by agents that disrupt RNA gelation in vitro. Analogous to protein aggregation disorders, our results suggest that the sequence-specific gelation of RNAs could be a contributing factor to neurological disease.
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Hu X, Kuang Y, Li L, Tang H, Shi Q, Shu X, Zhang Y, Chan FKL, Tao Q, He C. Epigenomic and Functional Characterization of Junctophilin 3 (JPH3) as a Novel Tumor Suppressor Being Frequently Inactivated by Promoter CpG Methylation in Digestive Cancers. Am J Cancer Res 2017; 7:2150-2163. [PMID: 28656064 PMCID: PMC5485426 DOI: 10.7150/thno.18185] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 04/04/2017] [Indexed: 12/28/2022] Open
Abstract
Junctophilin (JPH) proteins stabilize junctional membrane complexes between plasma membrane and endoplasmic reticulum, also implicated in some human diseases. JPH3 mutations are linked to Huntington's disease-like 2 syndrome. Through epigenomic study of a colon cancer cell line pair (HCT116 and DKO), we identified JPH3 as a methylated novel tumor suppressor gene (TSG) candidate at 16q24. We further studied its epigenetic alterations and functions in digestive tumorigenesis. JPH3 expression at the RNA level was found to be frequently silenced or reduced in colorectal and gastric cancers due to its promoter CpG methylation, which is associated with tumor progression and poor survival of digestive cancer patients. Ectopic expression of JPH3 inhibited tumor cell growth in vitro and in vivo. JPH3 expression upregulated the cytosolic Ca2+ levels, and unfolded protein response gene expression upon endoplasmic reticulum stress. JPH3 also induced calpain activation and subsequent mitochondrial membrane depolarization and cell apoptosis. Thus, JPH3 was identified as a novel TSG methylated in colorectal and gastric tumors which promotes mitochondrial-mediated apoptosis, also as a potential metastasis and survival biomarker for digestive cancers.
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Morriss GR, Cooper TA. Protein sequestration as a normal function of long noncoding RNAs and a pathogenic mechanism of RNAs containing nucleotide repeat expansions. Hum Genet 2017; 136:1247-1263. [PMID: 28484853 DOI: 10.1007/s00439-017-1807-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/28/2017] [Indexed: 12/12/2022]
Abstract
An emerging class of long noncoding RNAs (lncRNAs) function as decoy molecules that bind and sequester proteins thereby inhibiting their normal functions. Titration of proteins by lncRNAs has wide-ranging effects affecting nearly all steps in gene expression. While decoy lncRNAs play a role in normal physiology, RNAs expressed from alleles containing nucleotide repeat expansions can be pathogenic due to protein sequestration resulting in disruption of normal functions. This review focuses on commonalities between decoy lncRNAs that regulate gene expression by competitive inhibition of protein function through sequestration and specific examples of nucleotide repeat expansion disorders mediated by toxic RNA that sequesters RNA-binding proteins and impedes their normal functions. Understanding how noncoding RNAs compete with various RNA and DNA molecules for binding of regulatory proteins will provide insight into how similar mechanisms contribute to disease pathogenesis.
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Affiliation(s)
- Ginny R Morriss
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Thomas A Cooper
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.
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