1
|
Ferguson R, Goold R, Coupland L, Flower M, Tabrizi SJ. Therapeutic validation of MMR-associated genetic modifiers in a human ex vivo model of Huntington disease. Am J Hum Genet 2024; 111:1165-1183. [PMID: 38749429 PMCID: PMC11179424 DOI: 10.1016/j.ajhg.2024.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/18/2024] [Accepted: 04/18/2024] [Indexed: 06/09/2024] Open
Abstract
The pathological huntingtin (HTT) trinucleotide repeat underlying Huntington disease (HD) continues to expand throughout life. Repeat length correlates both with earlier age at onset (AaO) and faster progression, making slowing its expansion an attractive therapeutic approach. Genome-wide association studies have identified candidate variants associated with altered AaO and progression, with many found in DNA mismatch repair (MMR)-associated genes. We examine whether lowering expression of these genes affects the rate of repeat expansion in human ex vivo models using HD iPSCs and HD iPSC-derived striatal medium spiny neuron-enriched cultures. We have generated a stable CRISPR interference HD iPSC line in which we can specifically and efficiently lower gene expression from a donor carrying over 125 CAG repeats. Lowering expression of each member of the MMR complexes MutS (MSH2, MSH3, and MSH6), MutL (MLH1, PMS1, PMS2, and MLH3), and LIG1 resulted in characteristic MMR deficiencies. Reduced MSH2, MSH3, and MLH1 slowed repeat expansion to the largest degree, while lowering either PMS1, PMS2, or MLH3 slowed it to a lesser degree. These effects were recapitulated in iPSC-derived striatal cultures where MutL factor expression was lowered. CRISPRi-mediated lowering of key MMR factor expression to levels feasibly achievable by current therapeutic approaches was able to effectively slow the expansion of the HTT CAG tract. We highlight members of the MutL family as potential targets to slow pathogenic repeat expansion with the aim to delay onset and progression of HD and potentially other repeat expansion disorders exhibiting somatic instability.
Collapse
Affiliation(s)
- Ross Ferguson
- Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; Dementia Research Institute at UCL, London WC1N 3BG, UK
| | - Robert Goold
- Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; Dementia Research Institute at UCL, London WC1N 3BG, UK
| | - Lucy Coupland
- Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; Dementia Research Institute at UCL, London WC1N 3BG, UK
| | - Michael Flower
- Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; Dementia Research Institute at UCL, London WC1N 3BG, UK
| | - Sarah J Tabrizi
- Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; Dementia Research Institute at UCL, London WC1N 3BG, UK.
| |
Collapse
|
2
|
Bile Acids: A Communication Channel in the Gut-Brain Axis. Neuromolecular Med 2020; 23:99-117. [PMID: 33085065 DOI: 10.1007/s12017-020-08625-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/08/2020] [Indexed: 02/08/2023]
Abstract
Bile acids are signalling hormones involved in the regulation of several metabolic pathways. The ability of bile acids to bind and signal through their receptors is modulated by the gut microbiome, since the microbiome contributes to the regulation and synthesis of bile acids as well to their physiochemical properties. From the gut, bacteria have been shown to send signals to the central nervous system via their metabolites, thus affecting the behaviour and brain function of the host organism. In the last years it has become increasingly evident that bile acids affect brain function, during normal physiological and pathological conditions. Although bile acids may be synthesized locally in the brain, the majority of brain bile acids are taken up from the systemic circulation. Since the composition of the brain bile acid pool may be regulated by the action of intestinal bacteria, it is possible that bile acids function as a communication bridge between the gut microbiome and the brain. However, little is known about the molecular mechanisms and the physiological roles of bile acids in the central nervous system. The possibility that bile acids may be a direct link between the intestinal microbiome and the brain is also an understudied subject. Here we review the influence of gut bacteria on the bile acid pool composition and properties, as well as striking evidence showing the role of bile acids as neuroactive molecules.
Collapse
|
3
|
Zhao M, Cheah FSH, Tan ASC, Lian M, Phang GP, Agarwal A, Chong SS. Robust Preimplantation Genetic Testing of Huntington Disease by Combined Triplet-Primed PCR Analysis of the HTT CAG Repeat and Multi-Microsatellite Haplotyping. Sci Rep 2019; 9:16481. [PMID: 31712634 PMCID: PMC6848083 DOI: 10.1038/s41598-019-52769-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022] Open
Abstract
Huntington disease (HD) is a lethal neurodegenerative disorder caused by expansion of a CAG repeat within the huntingtin (HTT) gene. Disease prevention can be facilitated by preimplantation genetic testing for this monogenic disorder (PGT-M). We developed a strategy for HD PGT-M, involving whole genome amplification (WGA) followed by combined triplet-primed PCR (TP-PCR) for HTT CAG repeat expansion detection and multi-microsatellite marker genotyping for disease haplotype phasing. The strategy was validated and tested pre-clinically in a simulated PGT-M case before clinical application in five cycles of a PGT-M case. The assay reliably and correctly diagnosed all embryos, even where allele dropout (ADO) occurred at the HTT CAG repeat locus or at one or more linked markers. Ten of the 27 embryos analyzed were diagnosed as unaffected. Four embryo transfers were performed, two of which involved fresh cycle double embryo transfers and two were frozen-thawed single embryo transfers. Pregnancies were achieved from each of the frozen-thawed single embryo transfers and confirmed to be unaffected by amniocentesis, culminating in live births at term. This strategy enhances diagnostic confidence for PGT-M of HD and can also be employed in situations where disease haplotype phase cannot be established prior to the start of PGT-M.
Collapse
Affiliation(s)
- Mingjue Zhao
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Felicia Siew Hong Cheah
- Preimplantation Genetic Diagnosis Center, Khoo Teck Puat - National University Children's Medical Institute, National University Health System, Singapore, Singapore
| | - Arnold Sia Chye Tan
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Preimplantation Genetic Diagnosis Center, Khoo Teck Puat - National University Children's Medical Institute, National University Health System, Singapore, Singapore
| | - Mulias Lian
- Preimplantation Genetic Diagnosis Center, Khoo Teck Puat - National University Children's Medical Institute, National University Health System, Singapore, Singapore
| | - Gui Ping Phang
- Preimplantation Genetic Diagnosis Center, Khoo Teck Puat - National University Children's Medical Institute, National University Health System, Singapore, Singapore
| | - Anupriya Agarwal
- Clinic for Human Reproduction, Department of Obstetrics and Gynecology, National University Hospital, Singapore, Singapore
| | - Samuel S Chong
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,Preimplantation Genetic Diagnosis Center, Khoo Teck Puat - National University Children's Medical Institute, National University Health System, Singapore, Singapore. .,Molecular Diagnosis Center and Clinical Cytogenetics Service, Department of Laboratory Medicine, National University Hospital, Singapore, Singapore.
| |
Collapse
|
4
|
Chheda P, Chanekar M, Salunkhe Y, Dama T, Pais A, Pande S, Bendre R, Shah N. A Study of Triplet-Primed PCR for Identification of CAG Repeat Expansion in the HTT Gene in a Cohort of 503 Indian Cases with Huntington's Disease Symptoms. Mol Diagn Ther 2018; 22:353-359. [PMID: 29619771 DOI: 10.1007/s40291-018-0327-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder with an average age at onset of 40 years. It is a polyglutamine (polyQ) disorder that is caused by an increase in the number of CAG repeats in the huntingtin (HTT) gene. Genetic tests that accurately determine the number of CAG repeats are performed for confirmation of diagnosis, predictive testing of persons at genetic risk for inheriting HD, and prenatal testing. The aim of our study was to evaluate efficacy of triplet-primed polymerase chain reaction (TP-PCR) for routine diagnosis of HD in suspected cases from India. METHODS We evaluated a combination of CAG flanking PCR and triplet-primed PCR for estimation of CAG repeats in 503 cases with clinical suspicion of HD. RESULTS There were 250 cases (49.7%) that showed the presence of expanded alleles, with 241 (47.9%) being fully penetrant alleles and nine (1.8%) in the reduced penetrance category. There were seven juvenile cases with an age of onset of < 20 years, with the longest allele comprising 106 CAG repeats found in an 8-year-old male patient. The results demonstrated an inverse (R = - 0.67) relationship between CAG length and age at clinical onset. CONCLUSION Our study on pan-Indian cases is one of the largest studies reported so far in India and focuses on the most accurate and comprehensive molecular diagnostic evaluation of HD.
Collapse
Affiliation(s)
- Pratiksha Chheda
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India.
| | - Milind Chanekar
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Yogita Salunkhe
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Tavisha Dama
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Anurita Pais
- Genetics Department, Metropolis Healthcare Ltd, Mumbai, 400 070, India
| | - Shailesh Pande
- Genetics Department, Metropolis Healthcare Ltd, Mumbai, 400 070, India
| | - Rajesh Bendre
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| | - Nilesh Shah
- Department of Molecular Pathology, Metropolis Healthcare Ltd, Commercial Building A, Unit No. 409 to 416, 4th Floor, Kohinoor City, Near Kohinoor Mall, Kirol Road, Kurla-W, Mumbai, 400 070, India
| |
Collapse
|
5
|
Zhao M, Cheah FSH, Chen M, Lee CG, Law HY, Chong SS. Improved high sensitivity screen for Huntington disease using a one-step triplet-primed PCR and melting curve assay. PLoS One 2017; 12:e0180984. [PMID: 28700716 PMCID: PMC5507316 DOI: 10.1371/journal.pone.0180984] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 05/22/2017] [Indexed: 11/19/2022] Open
Abstract
Molecular diagnosis of Huntington disease (HD) is currently performed by fluorescent repeat-flanking or triplet-primed PCR (TP-PCR) with capillary electrophoresis (CE). However, CE requires multiple post-PCR steps and may result in high cost in high-throughput settings. We previously described a cost-effective single-step molecular screening strategy employing the use of melting curve analysis (MCA). However, because it relies on repeat-flanking PCR, its efficiency in detecting expansion mutations decreases with increasing size of the repeat, which could lead to false-negative results. To address this pitfall, we have developed an improved screening assay coupling TP-PCR, which has been shown in CE-based assays to detect all expanded alleles regardless of size, with MCA in a rapid one-step assay. A companion protocol for rapid size confirmation of expansion-positive samples is also described. The assay was optimized on 30 genotype-known DNAs, and two plasmids pHTT(CAG)26 and pHTT(CAG)33 were used to establish the threshold temperatures (TTs) distinguishing normal from expansion-positive samples. In contrast to repeat-flanking PCR MCA, TP-PCR MCA displayed much higher sensitivity for detecting large expansions. All 30 DNAs generated distinct melt peak Tms which correlated well with each sample's larger allele. Normal samples were clearly distinguished from affected samples. The companion sizing protocol accurately sized even the largest expanded allele of ~180 CAGs. Blinded analysis of 69 clinical samples enriched for HD demonstrated 100% assay sensitivity and specificity in sample segregation. The assay targets the HTT CAG repeat specifically, tolerates a wide range of input DNA, and works well using DNA from saliva and buccal swab in addition to blood. Therefore, rapid, accurate, reliable, and high-throughput detection/exclusion of HD can be achieved using this one-step screening assay, at less than half the cost of fluorescent PCR with CE.
Collapse
Affiliation(s)
- Mingjue Zhao
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Felicia S. H. Cheah
- Khoo Teck Puat – National University Children’s Medical Institute, National University Health System, Singapore, Singapore
| | - Min Chen
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Caroline G. Lee
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Division of Medical Sciences, National Cancer Center, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Hai-Yang Law
- Department of Pediatric Medicine, KK Women’s and Children’s Hospital, Singapore, Singapore
| | - Samuel S. Chong
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Khoo Teck Puat – National University Children’s Medical Institute, National University Health System, Singapore, Singapore
- Department of Laboratory Medicine, National University Hospital, Singapore, Singapore
- * E-mail:
| |
Collapse
|
6
|
Bouhouche A, Regragui W, Lamghari H, Khaldi K, Birouk N, Lytim S, Bellamine S, Kriouile Y, Bouslam N, Haddou EHAB, Faris MA, Benomar A, Yahyaoui M. Clinical and genetic data of Huntington disease in Moroccan patients. Afr Health Sci 2015; 15:1232-8. [PMID: 26958025 DOI: 10.4314/ahs.v15i4.23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Huntington's disease (HD) occurs worldwide with prevalence varying from 0.1 to 10/100,000 depending of the ethnic origin. Since no data is available in the Maghreb population, the aim of this study is to describe clinical and genetic characteristics of Huntington patients of Moroccan origin. METHODS Clinical and genetics data of 21 consecutive patients recruited from 2009 to 2014 from the outpatient clinic of six medical centers were analyzed. Statistical analysis was performed using descriptive statistics. RESULTS Twenty one patients from 17 families were diagnosed positive for the IT15 gene CAG expansion. Clinical symptoms were predominantly motor (19/21). Twelve patients had psychiatric and behavioral disorders, and 11 patients had cognitive disorders essentially of memory impairment. Analysis of genetic results showed that 5 patients had reduced penetrant (RP) alleles and 16 had fully penetrant (FP) alleles. The mean CAG repeat length in patients with RP alleles was 38.4 ± 0.54, and 45.37 ± 8.30 in FP alleles. The age of onset and the size of the CAG repeat length showed significant inverse correlation (p <0.001, r = -0.754). CONCLUSION Clinical and genetic data of Moroccan patients are similar to those of Caucasian populations previously reported in the literature.
Collapse
Affiliation(s)
- Ahmed Bouhouche
- Equipe de Recherche sur les Maladies Neurodégénératives, Faculté de Médecine et de Pharmacie, Université Mohammed V de Rabat, Morocco; Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| | - Wafaa Regragui
- Equipe de Recherche sur les Maladies Neurodégénératives, Faculté de Médecine et de Pharmacie, Université Mohammed V de Rabat, Morocco; Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| | | | | | - Nazha Birouk
- Service de Neurophysiologie clinique, Hôpital des Spécialités de Rabat, Morocco
| | - Safaa Lytim
- Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| | - Soufiane Bellamine
- Service de Neurologie et de Neuropsychologie, Hôpital des Spécialités de Rabat, Morocco
| | | | - Naima Bouslam
- Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| | - El Hachmia Ait Ben Haddou
- Equipe de Recherche sur les Maladies Neurodégénératives, Faculté de Médecine et de Pharmacie, Université Mohammed V de Rabat, Morocco; Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| | - Mustapha Alaoui Faris
- Service de Neurologie et de Neuropsychologie, Hôpital des Spécialités de Rabat, Morocco
| | - Ali Benomar
- Equipe de Recherche sur les Maladies Neurodégénératives, Faculté de Médecine et de Pharmacie, Université Mohammed V de Rabat, Morocco; Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| | - Mohamed Yahyaoui
- Equipe de Recherche sur les Maladies Neurodégénératives, Faculté de Médecine et de Pharmacie, Université Mohammed V de Rabat, Morocco; Service de Neurologie et de Neurogénétique, Hôpital des Spécialités de Rabat, Morocco
| |
Collapse
|
7
|
Kern A, Seitz O. Template-directed ligation on repetitive DNA sequences: a chemical method to probe the length of Huntington DNA. Chem Sci 2015; 6:724-728. [PMID: 28706635 PMCID: PMC5494559 DOI: 10.1039/c4sc01974a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/16/2014] [Indexed: 01/17/2023] Open
Abstract
Several genomic disorders are caused by an excessive number of DNA triplet repeats. We developed a DNA-templated reaction in which product formation occurs only when the number of repeats exceeds a threshold indicative for the outbreak of Chorea Huntington. The combined use of native chemical PNA ligation and auxiliary DNA probes enabled reactions on templates obtained from human genomic DNA.
Collapse
Affiliation(s)
- Anika Kern
- Institut für Chemie , Humboldt-Universität zu Berlin , Brook-Taylor-Straße 2 , 12489 Berlin , Germany .
| | - Oliver Seitz
- Institut für Chemie , Humboldt-Universität zu Berlin , Brook-Taylor-Straße 2 , 12489 Berlin , Germany .
| |
Collapse
|
8
|
Massai L, Petricca L, Magnoni L, Rovetini L, Haider S, Andre R, Tabrizi SJ, Süssmuth SD, Landwehrmeyer BG, Caricasole A, Pollio G, Bernocco S. Development of an ELISA assay for the quantification of soluble huntingtin in human blood cells. BMC BIOCHEMISTRY 2013; 14:34. [PMID: 24274906 PMCID: PMC4221641 DOI: 10.1186/1471-2091-14-34] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 11/19/2013] [Indexed: 11/10/2022]
Abstract
Background Huntington’s disease (HD) is a monogenic disorder caused by an aberrant expansion of CAG repeats in the huntingtin gene (HTT). Pathogenesis is associated with expression of the mutant (mHTT) protein in the CNS, with its levels most likely related to disease progression and symptom severity. Since non-invasive methods to quantify HTT in the CNS do not exist, measuring amount of soluble HTT in peripheral cells represents an important step in development of disease-modifying interventions in HD. Results An ELISA assay using commercially available antibodies was developed to quantify HTT levels in complex matrices like mammalian cell cultures lysates and human samples. The immunoassay was optimized using a recombinant full-length HTT protein, and validated both on wild-type and mutant HTT species. The ability of the assay to detect significant variations of soluble HTT levels was evaluated using an HSP90 inhibitor that is known to enhance HTT degradation. Once optimized, the bioassay was applied to peripheral blood mononuclear cells (PBMCs) from HD patients, demonstrating good potential in tracking the disease course. Conclusions The method described here represents a validated, simple and rapid bio-molecular assay to evaluate soluble HTT levels in blood cells as useful tool in disease and pharmacodynamic marker identification for observational and clinical trials.
Collapse
Affiliation(s)
- Luisa Massai
- Pharmacology Department, Siena Biotech SpA, Strada del Petriccio e Belriguardo, 35, 53100 Siena, Italy.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|