1
|
Zhao X, McHugh C, Coffey SR, Jimenez DA, Adams E, Carroll JB, Usdin K. Stool is a sensitive and noninvasive source of DNA for monitoring expansion in repeat expansion disease mouse models. Dis Model Mech 2022; 15:275011. [PMID: 35403689 PMCID: PMC9118036 DOI: 10.1242/dmm.049453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/05/2022] [Indexed: 11/27/2022] Open
Abstract
Repeat expansion diseases are a large group of human genetic disorders caused by expansion of a specific short tandem repeat tract. Expansion in somatic cells affects age of onset and disease severity in some of these disorders. However, alleles in DNA derived from blood, a commonly used source of DNA, usually show much less expansion than disease-relevant cells in the central nervous system in both humans and mouse models. Here we examined the extent of expansion in different DNA sources from mouse models of the fragile X-related disorders, Huntington's disease, spinocerebellar ataxia type 1 and spinocerebellar ataxia type 2. We found that DNA isolated from stool is a much better indicator of somatic expansion than DNA from blood. As stool is a sensitive and noninvasive source of DNA, it can be useful for studies of factors affecting the risk of expansion, or the monitoring of treatments aimed at reducing expansion in preclinical trials, as it would allow expansions to be examined longitudinally in the same animal and allow significant changes in expansion to be observed much earlier than is possible with other DNA sources. Summary: Stool is a readily available, noninvasive and sensitive source of DNA for monitoring repeat expansion in mouse models of four different repeat expansion diseases.
Collapse
Affiliation(s)
- Xiaonan Zhao
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cassandra McHugh
- Behavioral Neuroscience Program, Psychology Department, Western Washington University, Bellingham, WA 98225, USA
| | - Sydney R Coffey
- Behavioral Neuroscience Program, Psychology Department, Western Washington University, Bellingham, WA 98225, USA
| | - Diego Antonio Jimenez
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elizabeth Adams
- Behavioral Neuroscience Program, Psychology Department, Western Washington University, Bellingham, WA 98225, USA
| | - Jeffrey B Carroll
- Behavioral Neuroscience Program, Psychology Department, Western Washington University, Bellingham, WA 98225, USA
| | - Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
2
|
Larson E, Fyfe I, Morton AJ, Monckton DG. Age-, tissue- and length-dependent bidirectional somatic CAG•CTG repeat instability in an allelic series of R6/2 Huntington disease mice. Neurobiol Dis 2015; 76:98-111. [PMID: 25662336 DOI: 10.1016/j.nbd.2015.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/30/2014] [Accepted: 01/25/2015] [Indexed: 12/11/2022] Open
Abstract
The expansion of simple sequence CAG•CTG repeats is associated with a number of inherited disorders including Huntington disease (HD), myotonic dystrophy type 1 and several of the spinocerebellar ataxias. Inherited disease-associated alleles usually exceed 40 repeats and may be in excess of 1,000 repeats in some disorders. Inherited allele length is inversely proportional to age at onset, and frequent germline expansions account for the striking anticipation observed in affected families. Expanded disease associated alleles are also somatically unstable via a pathway that is age dependent and tissue specific, and also appears to be expansion biased. Somatic expansions are thought to contribute toward both tissue specificity and disease progression. Here we have examined the somatic mutational dynamics in brain and peripheral tissues from an allelic series of R6/2 HD transgenic mice inheriting from 52 to >700 CAG repeats. We found age-dependent, tissue-specific somatic instability, with particularly large expansions observed in the striatum and cortex. We also found a positive increase in somatic instability with increasing allele length. Surprisingly, however, the degree of somatic variation did not increase in a linear fashion, but leveled off with increasing allele length. Most unexpectedly, the almost exclusive bias toward the accumulation of expansions observed in mice inheriting smaller alleles was lost, and a high frequency of large somatic contractions was observed in mice inheriting very large alleles (>500 repeats). These data highlight the bidirectional nature of CAG•CTG repeat instability and the subtle balance that exists between expansion and contraction in vivo. Defining the dynamics and tissue specificity of expansion and contraction is important for understanding the role of genetic instability in pathophysiology and in particular the development of novel therapies based on suppressing expansions and/or promoting contractions.
Collapse
|
3
|
Fratta P, Polke JM, Newcombe J, Mizielinska S, Lashley T, Poulter M, Beck J, Preza E, Devoy A, Sidle K, Howard R, Malaspina A, Orrell RW, Clarke J, Lu CH, Mok K, Collins T, Shoaii M, Nanji T, Wray S, Adamson G, Pittman A, Renton AE, Traynor BJ, Sweeney MG, Revesz T, Houlden H, Mead S, Isaacs AM, Fisher EMC. Screening a UK amyotrophic lateral sclerosis cohort provides evidence of multiple origins of the C9orf72 expansion. Neurobiol Aging 2015; 36:546.e1-7. [PMID: 25179228 PMCID: PMC4270445 DOI: 10.1016/j.neurobiolaging.2014.07.037] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 07/27/2014] [Indexed: 12/13/2022]
Abstract
An expanded hexanucleotide repeat in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Although 0-30 hexanucleotide repeats are present in the general population, expansions >500 repeats are associated with C9ALS/FTD. Large C9ALS/FTD expansions share a common haplotype and whether these expansions derive from a single founder or occur more frequently on a predisposing haplotype is yet to be determined and is relevant to disease pathomechanisms. Furthermore, although cases carrying 50-200 repeats have been described, their role and the pathogenic threshold of the expansions remain to be identified and carry importance for diagnostics and genetic counseling. We present clinical and genetic data from a UK ALS cohort and report the detailed molecular study of an atypical somatically unstable expansion of 90 repeats. Our results across different tissues provide evidence for the pathogenicity of this repeat number by showing they can somatically expand in the central nervous system to the well characterized pathogenic range. Our results support the occurrence of multiple expansion events for C9ALS/FTD.
Collapse
Affiliation(s)
- Pietro Fratta
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Centre for Neuromuscular Diseases, University College London, Queen Square, London, UK.
| | | | - Jia Newcombe
- NeuroResource, Institute of Neurology, University College London, Queen Square, London, UK
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, University College London, Queen Square, London, UK
| | - Mark Poulter
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Prion Unit, University College London, Queen Square, London, UK
| | - Jon Beck
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Prion Unit, University College London, Queen Square, London, UK
| | - Elisavet Preza
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Anny Devoy
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Katie Sidle
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Robin Howard
- National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Andrea Malaspina
- National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Centre for Neuroscience & Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Richard W Orrell
- MRC Centre for Neuromuscular Diseases, University College London, Queen Square, London, UK; Department of Molecular Neuroscience, University College London, Queen Square, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Jan Clarke
- National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Ching-Hua Lu
- Centre for Neuroscience & Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK; Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Queen Square, London, UK
| | - Kin Mok
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Queen Square, London, UK
| | - Toby Collins
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Maryam Shoaii
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Tina Nanji
- Neurogenetics Unit, Queen Square, London, UK
| | - Selina Wray
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Gary Adamson
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Prion Unit, University College London, Queen Square, London, UK
| | - Alan Pittman
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Alan E Renton
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institutes of Health, National Institute on Aging, Bethesda, MD, USA
| | - Bryan J Traynor
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institutes of Health, National Institute on Aging, Bethesda, MD, USA
| | | | - Tamas Revesz
- Queen Square Brain Bank for Neurological Disorders, University College London, Queen Square, London, UK
| | - Henry Houlden
- Neurogenetics Unit, Queen Square, London, UK; Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Simon Mead
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Elizabeth M C Fisher
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Centre for Neuromuscular Diseases, University College London, Queen Square, London, UK.
| |
Collapse
|