1
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Boulos A, Maroun D, Ciechanover A, Ziv NE. Peripheral sequestration of huntingtin delays neuronal death and depends on N-terminal ubiquitination. Commun Biol 2024; 7:1014. [PMID: 39155290 PMCID: PMC11330980 DOI: 10.1038/s42003-024-06733-1] [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: 10/30/2023] [Accepted: 08/13/2024] [Indexed: 08/20/2024] Open
Abstract
Huntington's disease (HD) is caused by a glutamine repeat expansion in the protein huntingtin. Mutated huntingtin (mHtt) forms aggregates whose impacts on neuronal survival are still debated. Using weeks-long, continual imaging of cortical neurons, we find that mHtt is gradually sequestrated into peripheral, mainly axonal aggregates, concomitant with dramatic reductions in cytosolic mHtt levels and enhanced neuronal survival. in-situ pulse-chase imaging reveals that aggregates continually gain and lose mHtt, in line with these acting as mHtt sinks at equilibrium with cytosolic pools. Mutating two N-terminal lysines found to be ubiquitinated in HD animal models suppresses peripheral aggregate formation and reductions in cytosolic mHtt, promotes nuclear aggregate formation, stabilizes aggregates and leads to pervasive neuronal death. These findings demonstrate the capacity of aggregates formed at peripheral locations to sequester away cytosolic, presumably toxic mHtt forms and support a crucial role for N-terminal ubiquitination in promoting these processes and delaying neuronal death.
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Affiliation(s)
- Ayub Boulos
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Fishbach Building, Technion City, Haifa, Israel
- Department of Neurology, Massachusetts General Hospital, and Harvard Medical School, Charlestown, MA, USA
| | - Dunia Maroun
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Fishbach Building, Technion City, Haifa, Israel
| | - Aaron Ciechanover
- Rappaport Faculty of Medicine and Rappaport Technion Integrated Cancer Center (RTICC), Technion-Israel Institute of Technology, Haifa, Israel
| | - Noam E Ziv
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Fishbach Building, Technion City, Haifa, Israel.
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2
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Qian SX, Bao YF, Li XY, Dong Y, Zhang XL, Wu ZY. Multi-omics Analysis Reveals Key Gut Microbiota and Metabolites Closely Associated with Huntington's Disease. Mol Neurobiol 2024:10.1007/s12035-024-04271-9. [PMID: 38850348 DOI: 10.1007/s12035-024-04271-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/27/2024] [Indexed: 06/10/2024]
Abstract
Dysbiosis of the gut microbiota is closely associated with neurodegenerative diseases, including Huntington's disease (HD). Gut microbiome-derived metabolites are key factors in host-microbiome interactions. This study aimed to investigate the crucial gut microbiome and metabolites in HD and their correlations. Fecal and serum samples from 11 to 26 patients with HD, respectively, and 16 and 23 healthy controls, respectively, were collected. The fecal samples were used for shotgun metagenomics while the serum samples for metabolomics analysis. Integrated analysis of the metagenomics and metabolomics data was also conducted. Firmicutes, Bacteroidota, Proteobacteria, Uroviricota, Actinobacteria, and Verrucomicrobia were the dominant phyla. At the genus level, the presence of Bacteroides, Faecalibacterium, Parabacteroides, Alistipes, Dialister, and Christensenella was higher in HD patients, while the abundance of Lachnospira, Roseburia, Clostridium, Ruminococcus, Blautia, Butyricicoccus, Agathobaculum, Phocaeicola, Coprococcus, and Fusicatenibacter decreased. A total of 244 differential metabolites were identified and found to be enriched in the glycerophospholipid, nucleotide, biotin, galactose, and alpha-linolenic acid metabolic pathways. The AUC value from the integrated analysis (1) was higher than that from the analysis of the gut microbiota (0.8632). No significant differences were found in the ACE, Simpson, Shannon, Sobs, and Chao indexes between HD patients and controls. Our study determined crucial functional gut microbiota and potential biomarkers associated with HD pathogenesis, providing new insights into the role of the gut microbiota-brain axis in HD occurrence and development.
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Affiliation(s)
- Shu-Xia Qian
- Department of Medical Genetics and Center for Rare Diseases, Department of Neurology in the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, China
- Nanhu Brain-Computer Interface Institute, Hangzhou, China
- Department of Neurology, the Second Affiliated Hospital of Jiaxing University, 1518 Huancheng North Road, Jiaxing, Zhejiang, China
| | - Yu-Feng Bao
- Department of Medical Genetics and Center for Rare Diseases, Department of Neurology in the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, China
| | - Xiao-Yan Li
- Department of Medical Genetics and Center for Rare Diseases, Department of Neurology in the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, China
| | - Yi Dong
- Department of Medical Genetics and Center for Rare Diseases, Department of Neurology in the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, China
| | - Xiao-Ling Zhang
- Department of Neurology, the Second Affiliated Hospital of Jiaxing University, 1518 Huancheng North Road, Jiaxing, Zhejiang, China.
| | - Zhi-Ying Wu
- Department of Medical Genetics and Center for Rare Diseases, Department of Neurology in the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang, China.
- Nanhu Brain-Computer Interface Institute, Hangzhou, China.
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3
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Aldous SG, Smith EJ, Landles C, Osborne GF, Cañibano-Pico M, Nita IM, Phillips J, Zhang Y, Jin B, Hirst MB, Benn CL, Bond BC, Edelmann W, Greene JR, Bates GP. A CAG repeat threshold for therapeutics targeting somatic instability in Huntington's disease. Brain 2024; 147:1784-1798. [PMID: 38387080 PMCID: PMC11068328 DOI: 10.1093/brain/awae063] [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: 12/01/2023] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
The Huntington's disease mutation is a CAG repeat expansion in the huntingtin gene that results in an expanded polyglutamine tract in the huntingtin protein. The CAG repeat is unstable and expansions of hundreds of CAGs have been detected in Huntington's disease post-mortem brains. The age of disease onset can be predicted partially from the length of the CAG repeat as measured in blood. Onset age is also determined by genetic modifiers, which in six cases involve variation in DNA mismatch repair pathways genes. Knocking-out specific mismatch repair genes in mouse models of Huntington's disease prevents somatic CAG repeat expansion. Taken together, these results have led to the hypothesis that somatic CAG repeat expansion in Huntington's disease brains is required for pathogenesis. Therefore, the pathogenic repeat threshold in brain is longer than (CAG)40, as measured in blood, and is currently unknown. The mismatch repair gene MSH3 has become a major focus for therapeutic development, as unlike other mismatch repair genes, nullizygosity for MSH3 does not cause malignancies associated with mismatch repair deficiency. Potential treatments targeting MSH3 currently under development include gene therapy, biologics and small molecules, which will be assessed for efficacy in mouse models of Huntington's disease. The zQ175 knock-in model carries a mutation of approximately (CAG)185 and develops early molecular and pathological phenotypes that have been extensively characterized. Therefore, we crossed the mutant huntingtin allele onto heterozygous and homozygous Msh3 knockout backgrounds to determine the maximum benefit of targeting Msh3 in this model. Ablation of Msh3 prevented somatic expansion throughout the brain and periphery, and reduction of Msh3 by 50% decreased the rate of expansion. This had no effect on the deposition of huntingtin aggregation in the nuclei of striatal neurons, nor on the dysregulated striatal transcriptional profile. This contrasts with ablating Msh3 in knock-in models with shorter CAG repeat expansions. Therefore, further expansion of a (CAG)185 repeat in striatal neurons does not accelerate the onset of molecular and neuropathological phenotypes. It is striking that highly expanded CAG repeats of a similar size in humans cause disease onset before 2 years of age, indicating that somatic CAG repeat expansion in the brain is not required for pathogenesis. Given that the trajectory for somatic CAG expansion in the brains of Huntington's disease mutation carriers is unknown, our study underlines the importance of administering treatments targeting somatic instability as early as possible.
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Affiliation(s)
- Sarah G Aldous
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Edward J Smith
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Christian Landles
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Georgina F Osborne
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Maria Cañibano-Pico
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Iulia M Nita
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Jemima Phillips
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Yongwei Zhang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Bo Jin
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | | | - Caroline L Benn
- LoQus23 Therapeutics, Riverside, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Brian C Bond
- Prism Training and Consultancy Limited, St John's Innovation Centre, Cambridge, CB4 0WS, UK
| | - Winfried Edelmann
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | | | - Gillian P Bates
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
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4
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Mätlik K, Baffuto M, Kus L, Deshmukh AL, Davis DA, Paul MR, Carroll TS, Caron MC, Masson JY, Pearson CE, Heintz N. Cell-type-specific CAG repeat expansions and toxicity of mutant Huntingtin in human striatum and cerebellum. Nat Genet 2024; 56:383-394. [PMID: 38291334 PMCID: PMC10937393 DOI: 10.1038/s41588-024-01653-6] [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: 06/21/2023] [Accepted: 12/28/2023] [Indexed: 02/01/2024]
Abstract
Brain region-specific degeneration and somatic expansions of the mutant Huntingtin (mHTT) CAG tract are key features of Huntington's disease (HD). However, the relationships among CAG expansions, death of specific cell types and molecular events associated with these processes are not established. Here, we used fluorescence-activated nuclear sorting (FANS) and deep molecular profiling to gain insight into the properties of cell types of the human striatum and cerebellum in HD and control donors. CAG expansions arise at mHTT in striatal medium spiny neurons (MSNs), cholinergic interneurons and cerebellar Purkinje neurons, and at mutant ATXN3 in MSNs from SCA3 donors. CAG expansions in MSNs are associated with higher levels of MSH2 and MSH3 (forming MutSβ), which can inhibit nucleolytic excision of CAG slip-outs by FAN1. Our data support a model in which CAG expansions are necessary but may not be sufficient for cell death and identify transcriptional changes associated with somatic CAG expansions and striatal toxicity.
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Affiliation(s)
- Kert Mätlik
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Matthew Baffuto
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Laura Kus
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Amit Laxmikant Deshmukh
- Program of Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - David A Davis
- Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Matthew R Paul
- Bioinformatics Resource Center, The Rockefeller University, New York, NY, USA
| | - Thomas S Carroll
- Bioinformatics Resource Center, The Rockefeller University, New York, NY, USA
| | - Marie-Christine Caron
- CHU de Québec Research Center, Oncology Division, Laval University Cancer Research Center, Quebec City, Quebec, Canada
| | - Jean-Yves Masson
- CHU de Québec Research Center, Oncology Division, Laval University Cancer Research Center, Quebec City, Quebec, Canada
| | - Christopher E Pearson
- Program of Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Nathaniel Heintz
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA.
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5
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Olechnowicz A, Blatkiewicz M, Jopek K, Isalan M, Mielcarek M, Rucinski M. Deregulated Transcriptome as a Platform for Adrenal Huntington's Disease-Related Pathology. Int J Mol Sci 2024; 25:2176. [PMID: 38396853 PMCID: PMC10888552 DOI: 10.3390/ijms25042176] [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: 01/05/2024] [Revised: 01/31/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder that affects mainly the central nervous system (CNS) by inducing progressive deterioration in both its structure and function. In recent years, there has been growing interest in the impact of HD on peripheral tissue function. Herein, we used the R6/2 mouse model of HD to investigate the influence of the disease on adrenal gland functioning. A transcriptomic analysis conducted using a well-established quantitative method, an Affymetrix array, revealed changes in gene expression in the R6/2 model compared to genetic background controls. For the first time, we identified disruptions in cholesterol and sterol metabolism, blood coagulation, and xenobiotic metabolism in HD adrenal glands. This study showed that the disrupted expression of these genes may contribute to the underlying mechanisms of Huntington's disease. Our findings may contribute to developing a better understanding of Huntington's disease progression and aid in the development of novel diagnostic or therapeutic approaches.
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Affiliation(s)
- Anna Olechnowicz
- Department of Histology and Embryology, Poznan University of Medical Sciences, 61-701 Poznan, Poland
- Doctoral School, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Małgorzata Blatkiewicz
- Department of Histology and Embryology, Poznan University of Medical Sciences, 61-701 Poznan, Poland
| | - Karol Jopek
- Department of Histology and Embryology, Poznan University of Medical Sciences, 61-701 Poznan, Poland
| | - Mark Isalan
- Department of Life Sciences, Imperial College London, Exhibition Road, London SW7 2AZ, UK
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Michal Mielcarek
- Department of Life Sciences, Imperial College London, Exhibition Road, London SW7 2AZ, UK
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Marcin Rucinski
- Department of Histology and Embryology, Poznan University of Medical Sciences, 61-701 Poznan, Poland
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6
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Sena LS, Lemes RB, Furtado GV, Saraiva-Pereira ML, Jardim LB. A model for the dynamics of expanded CAG repeat alleles: ATXN2 and ATXN3 as prototypes. Front Genet 2023; 14:1296614. [PMID: 38034492 PMCID: PMC10682950 DOI: 10.3389/fgene.2023.1296614] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 10/27/2023] [Indexed: 12/02/2023] Open
Abstract
Background: Spinocerebellar ataxia types 2 (SCA2) and 3 (SCA3/MJD) are diseases due to dominant unstable expansions of CAG repeats (CAGexp). Age of onset of symptoms (AO) correlates with the CAGexp length. Repeat instability leads to increases in the expanded repeats, to important AO anticipations and to the eventual extinction of lineages. Because of that, compensatory forces are expected to act on the maintenance of expanded alleles, but they are poorly understood. Objectives: we described the CAGexp dynamics, adapting a classical equation and aiming to estimate for how many generations will the descendants of a de novo expansion last. Methods: A mathematical model was adapted to encompass anticipation, fitness, and allelic segregation; and empirical data fed the model. The arbitrated ancestral mutations included in the model had the lowest CAGexp and the highest AO described in the literature. One thousand generations were simulated until the alleles were eliminated, fixed, or 650 generations had passed. Results: All SCA2 lineages were eliminated in a median of 10 generations. In SCA3/MJD lineages, 593 were eliminated in a median of 29 generations. The other ones were eliminated due to anticipation after the 650th generation or remained indefinitely with CAG repeats transitioning between expanded and unexpanded ranges. Discussion: the model predicted outcomes compatible with empirical data - the very old ancestral SCA3/MJD haplotype, and the de novo SCA2 expansions -, which previously seemed to be contradictory. This model accommodates these data into understandable dynamics and might be useful for other CAGexp disorders.
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Affiliation(s)
- Lucas Schenatto Sena
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | | | - Gabriel Vasata Furtado
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Maria Luiza Saraiva-Pereira
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Laura Bannach Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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7
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Xie J, Kittur FS, Hung CY, Ding TT. Regulation of one-carbon metabolism may open new avenues to slow down the initiation and progression of Huntington's disease. Neural Regen Res 2023; 18:2401-2402. [PMID: 37282468 PMCID: PMC10360093 DOI: 10.4103/1673-5374.371363] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/09/2023] [Accepted: 02/23/2023] [Indexed: 06/08/2023] Open
Affiliation(s)
- Jiahua Xie
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC, USA
| | - Farooqahmed S. Kittur
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC, USA
| | - Chiu-Yueh Hung
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC, USA
| | - Tomas T. Ding
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC, USA
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Pant A, Vasundhara M. Endophytic fungi: a potential source for drugs against central nervous system disorders. Braz J Microbiol 2023; 54:1479-1499. [PMID: 37165297 PMCID: PMC10485218 DOI: 10.1007/s42770-023-00997-1] [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: 10/02/2022] [Accepted: 04/27/2023] [Indexed: 05/12/2023] Open
Abstract
Neuroprotection is one of the important protection methods against neuronal cells and tissue damage caused by neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and multiple sclerosis. Various bioactive compounds produced by medicinal plants can potentially treat central nervous system (CNS) disorders. Apart from these resources, endophytes also produce diverse secondary metabolites capable of protecting the CNS. The bioactive compounds produced by endophytes play essential roles in enhancing the growth factors, antioxidant defence functions, diminishing neuroinflammatory, and apoptotic pathways. The efficacy of compounds produced by endophytic fungi was also evaluated by enzymes, cell lines, and in vivo models. Acetylcholine esterase (AChE) inhibition is frequently used to assess in vitro neuroprotective activity along with cytotoxicity-induced neuronal cell lines. Some of drugs, such as tacrine, donepezil, rivastigmine, galantamine, and other compounds, are generally used as reference standards. Furthermore, clinical trials are required to confirm the role of these natural compounds in neuroprotection efficacy and evaluate their safety profile. This review illustrates the production of various bioactive compounds produced by endophytic fungi and their role in preventing neurodegeneration.
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Affiliation(s)
- Anushree Pant
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala, Punjab, 147004, India
| | - M Vasundhara
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala, Punjab, 147004, India.
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9
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Mätlik K, Baffuto M, Kus L, Deshmukh AL, Davis DA, Paul MR, Carroll TS, Caron MC, Masson JY, Pearson CE, Heintz N. Cell Type Specific CAG Repeat Expansions and Toxicity of Mutant Huntingtin in Human Striatum and Cerebellum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538082. [PMID: 37333326 PMCID: PMC10274669 DOI: 10.1101/2023.04.24.538082] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Brain region-specific degeneration and somatic expansions of the mutant Huntingtin (mHTT) CAG tract are key features of Huntington's disease (HD). However, the relationships between CAG expansions, death of specific cell types, and molecular events associated with these processes are not established. Here we employed fluorescence-activated nuclear sorting (FANS) and deep molecular profiling to gain insight into the properties of cell types of the human striatum and cerebellum in HD and control donors. CAG expansions arise in striatal medium spiny neurons (MSNs) and cholinergic interneurons, in cerebellar Purkinje neurons, and at mATXN3 in MSNs from SCA3 donors. CAG expansions in MSNs are associated with higher levels of MSH2 and MSH3 (forming MutSβ), which can inhibit nucleolytic excision of CAG slip-outs by FAN1 in a concentration-dependent manner. Our data indicate that ongoing CAG expansions are not sufficient for cell death, and identify transcriptional changes associated with somatic CAG expansions and striatal toxicity.
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10
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Rnq1! You are still dangerous, but you can be my wingman anytime. Mol Cell 2022; 82:4194-4196. [PMID: 36400005 DOI: 10.1016/j.molcel.2022.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 10/18/2022] [Accepted: 10/18/2022] [Indexed: 11/19/2022]
Abstract
In this issue of Molecular Cell, Gropp et al. identify how the cellular background affects whether or not the Huntington's disease protein will form toxic pathological aggregates, providing insight into selective neuronal vulnerability in neurodegenerative disease.
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11
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Seefelder M, Klein FAC, Landwehrmeyer B, Fernández-Busnadiego R, Kochanek S. Huntingtin and Its Partner Huntingtin-Associated Protein 40: Structural and Functional Considerations in Health and Disease. J Huntingtons Dis 2022; 11:227-242. [PMID: 35871360 PMCID: PMC9484127 DOI: 10.3233/jhd-220543] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the discovery of the mutation causing Huntington’s disease (HD) in 1993, it has been debated whether an expanded polyglutamine (polyQ) stretch affects the properties of the huntingtin (HTT) protein and thus contributes to the pathological mechanisms responsible for HD. Here we review the current knowledge about the structure of HTT, alone (apo-HTT) or in a complex with Huntingtin-Associated Protein 40 (HAP40), the influence of polyQ-length variation on apo-HTT and the HTT-HAP40 complex, and the biology of HAP40. Phylogenetic analyses suggest that HAP40 performs essential functions. Highlighting the relevance of its interaction with HTT, HAP40 is one of the most abundant partners copurifying with HTT and is rapidly degraded, when HTT levels are reduced. As the levels of both proteins decrease during disease progression, HAP40 could also be a biomarker for HD. Whether declining HAP40 levels contribute to disease etiology is an open question. Structural studies have shown that the conformation of apo-HTT is less constrained but resembles that adopted in the HTT-HAP40 complex, which is exceptionally stable because of extensive interactions between HAP40 and the three domains of HTT. The complex— and to some extent apo-HTT— resists fragmentation after limited proteolysis. Unresolved regions of apo-HTT, constituting about 25% of the protein, are the main sites of post-translational modifications and likely have major regulatory functions. PolyQ elongation does not substantially alter the structure of HTT, alone or when associated with HAP40. Particularly, polyQ above the disease length threshold does not induce drastic conformational changes in full-length HTT. Therefore, models of HD pathogenesis stating that polyQ expansion drastically alters HTT properties should be reconsidered.
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Affiliation(s)
| | | | | | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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12
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Warner JH, Long JD, Mills JA, Langbehn DR, Ware J, Mohan A, Sampaio C. Standardizing the CAP Score in Huntington's Disease by Predicting Age-at-Onset. J Huntingtons Dis 2022; 11:153-171. [PMID: 35466943 DOI: 10.3233/jhd-210475] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Huntington's disease (HD) is an autosomal dominant, neurological disease caused by an expanded CAG repeat near the N-terminus of the huntingtin (HTT) gene. A leading theory concerning the etiology of HD is that both onset and progression are driven by cumulative exposure to the effects of mutant (or CAG expanded) huntingtin (mHTT). The CAG-Age-Product (CAP) score (i.e., the product of excess CAG length and age) is a commonly used measure of this cumulative exposure. CAP score has been widely used as a predictor of a variety of disease state variables in HD. The utility of the CAP score has been somewhat diminished, however, by a lack of agreement on its precise definition. The most commonly used forms of the CAP score are highly correlated so that, for purposes of prediction, it makes little difference which is used. However, reported values of CAP scores, based on commonly used definitions, differ substantially in magnitude when applied to the same data. This complicates the process of inter-study comparison. OBJECTIVE In this paper, we propose a standardized definition for the CAP score which will resolve this difficulty. Our standardization is chosen so that CAP = 100 at the expected age of diagnosis. METHODS Statistical methods include novel survival analysis methodology applied to the 13 disease landmarks taken from the Enroll-HD database (PDS 5) and comparisons with the existing, gold standard, onset model. RESULTS Useful by-products of our work include up-to-date, age-at-onset (AO) results and a refined AO model suitable for use in other contexts, a discussion of several useful properties of the CAP score that have not previously been noted in the literature and the introduction of the concept of a toxicity onset model. CONCLUSION We suggest that taking L = 30 and K = 6.49 provides a useful standardization of the CAP score, suitable for use in the routine modeling of clinical data in HD.
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Affiliation(s)
| | - Jeffrey D Long
- Departments of Psychiatry, Biostatistics, University of Iowa, Iowa City, IA, USA
| | - James A Mills
- Departments of Psychiatry, Biostatistics, University of Iowa, Iowa City, IA, USA
| | - Douglas R Langbehn
- Departments of Psychiatry, Biostatistics, University of Iowa, Iowa City, IA, USA
| | | | - Amrita Mohan
- CHDI Management/CHDI Foundation, Princeton, NJ, USA
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13
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Paul BD. Cysteine metabolism and hydrogen sulfide signaling in Huntington's disease. Free Radic Biol Med 2022; 186:93-98. [PMID: 35550919 PMCID: PMC10066926 DOI: 10.1016/j.freeradbiomed.2022.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/17/2022] [Accepted: 05/05/2022] [Indexed: 02/06/2023]
Abstract
The semi-essential amino acid, cysteine, plays important roles in both essential cellular processes as well as in modulation of signaling cascades. Cysteine is obtained both from the diet as well as generated endogenously via the transsulfuration pathway. Cysteine is further utilized in protein synthesis and biosynthesis of various sulfur containing molecules. One of the products of cysteine catabolism, hydrogen sulfide (H2S), is a gaseous signaling molecule, which regulates a multitude of cellular processes. Cysteine metabolism is dysregulated in several neurodegenerative diseases and during aging. This minireview focuses on aberrant cysteine and H2S metabolism in Huntington's disease, a neurodegenerative disease caused by expansion of polyglutamine encoding repeats in the gene huntingtin, which leads to motor and cognitive deficits.
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Affiliation(s)
- Bindu D Paul
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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14
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Petracca M, Di Tella S, Solito M, Zinzi P, Lo Monaco MR, Di Lazzaro G, Calabresi P, Silveri MC, Bentivoglio AR. Clinical and genetic characteristics of late-onset Huntington's disease in a large European cohort. Eur J Neurol 2022; 29:1940-1951. [PMID: 35357736 PMCID: PMC9324106 DOI: 10.1111/ene.15340] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/15/2022] [Accepted: 03/24/2022] [Indexed: 11/28/2022]
Abstract
Background and purpose Huntington's disease (HD) is an autosomal dominant condition caused by CAG‐triplet repeat expansions. CAG‐triplet repeat expansion is inversely correlated with age of onset in HD and largely determines the clinical features. The aim of this study was to examine the phenotypic and genotypic correlates of late‐onset HD (LoHD) and to determine whether LoHD is a more benign expression of HD. Methods This was a retrospective observational study of 5053 White European HD patients from the ENROLL‐HD database. Sociodemographic, genetic and phenotypic variables at baseline evaluation of subjects with LoHD, common‐onset HD (CoHD) and young‐onset HD (YoHD) were compared. LoHD subjects were compared with healthy subjects (HS) aged ≥60 years. Differences between the CoHD and LoHD groups were also explored in subjects with 41 CAG triplets, a repeat number in the lower pathological expansion range associated with wide variability in age at onset. Results Late‐onset HD presented predominantly as motor‐onset disease, with a lower prevalence of both psychiatric history and current symptomatology. Absent/unknown HD family history was significantly more common in the LoHD group (31.2%) than in the other groups. The LoHD group had more severe motor and cognitive deficits than the HS group. Subjects with LoHD and CoHD with 41 triplets in the larger allele were comparable with regard to cognitive impairment, but those with LoHD had more severe motor disorders, less problematic behaviors and more often an unknown HD family history. Conclusions It is likely that cognitive disorders and motor symptoms of LoHD are at least partly age‐related and not a direct expression of the disease. In addition to CAG‐triplet repeat expansion, future studies should investigate the role of other genetic and environmental factors in determining age of onset.
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Affiliation(s)
- M Petracca
- Movement Disorders Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome
| | - S Di Tella
- Department of Psychology, Università Cattolica del Sacro Cuore, 20123, Milan
| | - M Solito
- Movement Disorders Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome
| | - P Zinzi
- Movement Disorders Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome.,Clinical Psychology Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome
| | - M R Lo Monaco
- Geriatric Day-Hospital, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome.,Medicine of the Ageing, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome
| | - G Di Lazzaro
- Movement Disorders Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome.,Department of Systems Medicine, University of Rome Tor Vergata, Rome
| | - P Calabresi
- Movement Disorders Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome.,Institute of Neurology, Università Cattolica del Sacro Cuore, Rome
| | - M C Silveri
- Department of Psychology, Università Cattolica del Sacro Cuore, 20123, Milan.,Medicine of the Ageing, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome
| | - A R Bentivoglio
- Movement Disorders Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome.,Institute of Neurology, Università Cattolica del Sacro Cuore, Rome
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