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Tong H, Yang T, Xu S, Li X, Liu L, Zhou G, Yang S, Yin S, Li XJ, Li S. Huntington's Disease: Complex Pathogenesis and Therapeutic Strategies. Int J Mol Sci 2024; 25:3845. [PMID: 38612657 PMCID: PMC11011923 DOI: 10.3390/ijms25073845] [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: 02/19/2024] [Revised: 03/21/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
Huntington's disease (HD) arises from the abnormal expansion of CAG repeats in the huntingtin gene (HTT), resulting in the production of the mutant huntingtin protein (mHTT) with a polyglutamine stretch in its N-terminus. The pathogenic mechanisms underlying HD are complex and not yet fully elucidated. However, mHTT forms aggregates and accumulates abnormally in neuronal nuclei and processes, leading to disruptions in multiple cellular functions. Although there is currently no effective curative treatment for HD, significant progress has been made in developing various therapeutic strategies to treat HD. In addition to drugs targeting the neuronal toxicity of mHTT, gene therapy approaches that aim to reduce the expression of the mutant HTT gene hold great promise for effective HD therapy. This review provides an overview of current HD treatments, discusses different therapeutic strategies, and aims to facilitate future therapeutic advancements in the field.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Xiao-Jiang Li
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (H.T.); (T.Y.); (S.X.); (X.L.); (L.L.); (G.Z.); (S.Y.); (S.Y.)
| | - Shihua Li
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (H.T.); (T.Y.); (S.X.); (X.L.); (L.L.); (G.Z.); (S.Y.); (S.Y.)
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2
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Mitchell B, Thor S, Piper M. Cellular and molecular functions of SETD2 in the central nervous system. J Cell Sci 2023; 136:jcs261406. [PMID: 37921122 DOI: 10.1242/jcs.261406] [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] [Indexed: 11/04/2023] Open
Abstract
The covalent modification of histones is critical for many biological functions in mammals, including gene regulation and chromatin structure. Posttranslational histone modifications are added and removed by specialised 'writer' and 'eraser' enzymes, respectively. One such writer protein implicated in a wide range of cellular processes is SET domain-containing 2 (SETD2), a histone methyltransferase that catalyses the trimethylation of lysine 36 on histone H3 (H3K36me3). Recently, SETD2 has also been found to modify proteins other than histones, including actin and tubulin. The emerging roles of SETD2 in the development and function of the mammalian central nervous system (CNS) are of particular interest as several SETD2 variants have been implicated in neurodevelopmental disorders, such as autism spectrum disorder and the overgrowth disorder Luscan-Lumish syndrome. Here, we summarise the numerous roles of SETD2 in mammalian cellular functions and development, with a focus on the CNS. We also provide an overview of the consequences of SETD2 variants in human disease and discuss future directions for understanding essential cellular functions of SETD2.
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Affiliation(s)
- Benjamin Mitchell
- The School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stefan Thor
- The School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Michael Piper
- The School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
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3
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Kim H, Lenoir S, Helfricht A, Jung T, Karneva ZK, Lee Y, Beumer W, van der Horst GB, Anthonijsz H, Buil LC, van der Ham F, Platenburg GJ, Purhonen P, Hebert H, Humbert S, Saudou F, Klein P, Song JJ. A pathogenic proteolysis-resistant huntingtin isoform induced by an antisense oligonucleotide maintains huntingtin function. JCI Insight 2022; 7:154108. [PMID: 35943803 PMCID: PMC9536263 DOI: 10.1172/jci.insight.154108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 08/03/2022] [Indexed: 11/17/2022] Open
Abstract
Huntington’s disease (HD) is a late-onset neurological disorder for which therapeutics are not available. Its key pathological mechanism involves the proteolysis of polyglutamine-expanded (polyQ-expanded) mutant huntingtin (mHTT), which generates N-terminal fragments containing polyQ, a key contributor to HD pathogenesis. Interestingly, a naturally occurring spliced form of HTT mRNA with truncated exon 12 encodes an HTT (HTTΔ12) with a deletion near the caspase-6 cleavage site. In this study, we used a multidisciplinary approach to characterize the therapeutic potential of targeting HTT exon 12. We show that HTTΔ12 was resistant to caspase-6 cleavage in both cell-free and tissue lysate assays. However, HTTΔ12 retained overall biochemical and structural properties similar to those of wt-HTT. We generated mice in which HTT exon 12 was truncated and found that the canonical exon 12 was dispensable for the main physiological functions of HTT, including embryonic development and intracellular trafficking. Finally, we pharmacologically induced HTTΔ12 using the antisense oligonucleotide (ASO) QRX-704. QRX-704 showed predictable pharmacology and efficient biodistribution. In addition, it was stable for several months and inhibited pathogenic proteolysis. Furthermore, QRX-704 treatments resulted in a reduction of HTT aggregation and an increase in dendritic spine count. Thus, ASO-induced HTT exon 12 splice switching from HTT may provide an alternative therapeutic strategy for HD.
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Affiliation(s)
- Hyeongju Kim
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| | - Sophie Lenoir
- Grenoble Institute Neurosciences, University Grenoble Alpes, Grenoble, France
| | | | - Taeyang Jung
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| | | | - Yejin Lee
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
| | | | | | | | | | | | | | - Pasi Purhonen
- Department of Biomedical Engineering and Health Systems, The Royal Institute of Technology, KTH, Huddinge, Sweden
| | - Hans Hebert
- Department of Biomedical Engineering and Health Systems, The Royal Institute of Technology, KTH, Huddinge, Sweden
| | - Sandrine Humbert
- Grenoble Institute Neurosciences, University Grenoble Alpes, Grenoble, France
| | - Frédéric Saudou
- Grenoble Institute Neurosciences, University Grenoble Alpes, Grenoble, France
| | | | - Ji-Joon Song
- Department of Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology), Daejeon, Korea, Republic of
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4
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Fields E, Vaughan E, Tripu D, Lim I, Shrout K, Conway J, Salib N, Lee Y, Dhamsania A, Jacobsen M, Woo A, Xue H, Cao K. Gene targeting techniques for Huntington's disease. Ageing Res Rev 2021; 70:101385. [PMID: 34098113 PMCID: PMC8373677 DOI: 10.1016/j.arr.2021.101385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 02/08/2023]
Abstract
Huntington's disease (HD) is an autosomal neurodegenerative disorder caused by extended trinucleotide CAG repetition in the HTT gene. Wild-type huntingtin protein (HTT) is essential, involved in a variety of crucial cellular functions such as vesicle transportation, cell division, transcription regulation, autophagy, and tissue maintenance. The mutant HTT (mHTT) proteins in the body interfere with HTT's normal cellular functions and cause additional detrimental effects. In this review, we discuss multiple approaches targeting DNA and RNA to reduce mHTT expression. These approaches are categorized into non-allele-specific silencing and allele-specific-silencing using Single Nucleotide Polymorphisms (SNPs) and haplogroup analysis. Additionally, this review discusses a potential application of recent CRISPR prime editing technology in targeting HD.
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Affiliation(s)
- Eric Fields
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Erik Vaughan
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Deepika Tripu
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Isabelle Lim
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Katherine Shrout
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Jessica Conway
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Nicole Salib
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Yubin Lee
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Akash Dhamsania
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Michael Jacobsen
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Ashley Woo
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States
| | - Huijing Xue
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, United States
| | - Kan Cao
- Gemstone Honors Program, University of Maryland, College Park, MD 20742, United States; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, United States.
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5
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Barron JC, Hurley EP, Parsons MP. Huntingtin and the Synapse. Front Cell Neurosci 2021; 15:689332. [PMID: 34211373 PMCID: PMC8239291 DOI: 10.3389/fncel.2021.689332] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/24/2021] [Indexed: 12/16/2022] Open
Abstract
Huntington disease (HD) is a monogenic disease that results in a combination of motor, psychiatric and cognitive symptoms. HD is caused by a CAG trinucleotide repeat expansion in the huntingtin (HTT) gene, which results in the production of a pathogenic mutant HTT protein (mHTT). Although there is no cure at present for HD, a number of RNA-targeting therapies have recently entered clinical trials which aim to lower mHTT production through the use of antisense oligonucleotides (ASOs) and RNAi. However, many of these treatment strategies are non-selective in that they cannot differentiate between non-pathogenic wild type HTT (wtHTT) and the mHTT variant. As HD patients are already born with decreased levels of wtHTT, these genetic therapies may result in critically low levels of wtHTT. The consequence of wtHTT reduction in the adult brain is currently under debate, and here we argue that wtHTT loss is not well-tolerated at the synaptic level. Synaptic dysfunction is an extremely sensitive measure of subsequent cell death, and is known to precede neurodegeneration in numerous brain diseases including HD. The present review focuses on the prominent role of wtHTT at the synapse and considers the consequences of wtHTT loss on both pre- and postsynaptic function. We discuss how wtHTT is implicated in virtually all major facets of synaptic neurotransmission including anterograde and retrograde transport of proteins to/from terminal buttons and dendrites, neurotransmitter release, endocytic vesicle recycling, and postsynaptic receptor localization and recycling. We conclude that wtHTT presence is essential for proper synaptic function.
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Affiliation(s)
- Jessica C Barron
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Emily P Hurley
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Matthew P Parsons
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
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6
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Agasse F, Mendez-David I, Christaller W, Carpentier R, Braz BY, David DJ, Saudou F, Humbert S. Chronic Corticosterone Elevation Suppresses Adult Hippocampal Neurogenesis by Hyperphosphorylating Huntingtin. Cell Rep 2021; 32:107865. [PMID: 32640230 DOI: 10.1016/j.celrep.2020.107865] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 02/12/2020] [Accepted: 06/16/2020] [Indexed: 01/02/2023] Open
Abstract
Chronic exposure to stress is a major risk factor for neuropsychiatric disease, and elevated plasma corticosterone (CORT) correlates with reduced levels of both brain-derived neurotrophic factor (BDNF) and hippocampal neurogenesis. Precisely how these phenomena are linked, however, remains unclear. Using a cortico-hippocampal network-on-a-chip, we find that the glucocorticoid receptor agonist dexamethasone (DXM) stimulates the cyclin-dependent kinase 5 (CDK5) to phosphorylate huntingtin (HTT) at serines 1181 and 1201 (S1181/1201), which retards BDNF vesicular transport in cortical axons. Parallel studies in mice show that CORT induces phosphorylation of these same residues, reduces BDNF levels, and suppresses neurogenesis. The adverse effects of CORT are reduced in mice bearing an unphosphorylatable mutant HTT (HdhS1181A/S1201A). The protective effect of unphosphorylatable HTT, however, disappears if neurogenesis is blocked. The CDK5-HTT pathway, which regulates BDNF transport in the cortico-hippocampal network, thus provides a missing link between elevated CORT levels and suppressed neurogenesis.
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Affiliation(s)
- Fabienne Agasse
- Université Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Indira Mendez-David
- Université Paris-Saclay, Centre de Recherche en Epidémiologie et Santé des Populations (CESP), INSERM, Faculté de Pharmacie, 92290 Châtenay-Malabry, France
| | - Wilhelm Christaller
- Université Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Rémi Carpentier
- Université Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Barbara Y Braz
- Université Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Denis J David
- Université Paris-Saclay, Centre de Recherche en Epidémiologie et Santé des Populations (CESP), INSERM, Faculté de Pharmacie, 92290 Châtenay-Malabry, France
| | - Frédéric Saudou
- Université Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Sandrine Humbert
- Université Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, 38000 Grenoble, France.
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7
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Virlogeux A, Scaramuzzino C, Lenoir S, Carpentier R, Louessard M, Genoux A, Lino P, Hinckelmann MV, Perrier AL, Humbert S, Saudou F. Increasing brain palmitoylation rescues behavior and neuropathology in Huntington disease mice. SCIENCE ADVANCES 2021; 7:7/14/eabb0799. [PMID: 33789888 PMCID: PMC8011966 DOI: 10.1126/sciadv.abb0799] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 02/11/2021] [Indexed: 05/02/2023]
Abstract
Huntington disease (HD) damages the corticostriatal circuitry in large part by impairing transport of brain-derived neurotrophic factor (BDNF). We hypothesized that improving vesicular transport of BDNF could slow or prevent disease progression. We therefore performed selective proteomic analysis of vesicles transported within corticostriatal projecting neurons followed by in silico screening and identified palmitoylation as a pathway that could restore defective huntingtin-dependent trafficking. Using a synchronized trafficking assay and an HD network-on-a-chip, we found that increasing brain palmitoylation via ML348, which inhibits the palmitate-removing enzyme acyl-protein thioesterase 1 (APT1), restores axonal transport, synapse homeostasis, and survival signaling to wild-type levels without toxicity. In human HD induced pluripotent stem cell-derived cortical neurons, ML348 increased BDNF trafficking. In HD knock-in mice, it efficiently crossed the blood-brain barrier to restore palmitoylation levels and reverse neuropathology, locomotor deficits, and anxio-depressive behaviors. APT1 and its inhibitor ML348 thus hold therapeutic interest for HD.
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Affiliation(s)
- Amandine Virlogeux
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | - Chiara Scaramuzzino
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | - Sophie Lenoir
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | - Rémi Carpentier
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | | | - Aurélie Genoux
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | - Patricia Lino
- INSERM U861, UEVE, I-STEM, AFM, 91100, Corbeil-Essonnes, France
| | - Maria-Victoria Hinckelmann
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | - Anselme L Perrier
- INSERM U861, UEVE, I-STEM, AFM, 91100, Corbeil-Essonnes, France
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Direction de la Recherche Fondamentale, Institut François Jacob, Molecular Imaging Center (MIRCen), CNRS UMR 9199, Université Paris-Saclay, 92265, Fontenay-aux-Roses, France
| | - Sandrine Humbert
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France
| | - Frédéric Saudou
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, GIN, 38000, Grenoble, France.
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8
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Leavitt BR, Kordasiewicz HB, Schobel SA. Huntingtin-Lowering Therapies for Huntington Disease: A Review of the Evidence of Potential Benefits and Risks. JAMA Neurol 2021; 77:764-772. [PMID: 32202594 DOI: 10.1001/jamaneurol.2020.0299] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Huntington disease (HD) is caused by a cytosine-adenine-guanine trinucleotide repeat expansion in the huntingtin gene, HTT, that results in expression of variant (mutant) huntingtin protein (HTT). Therapeutic strategies that reduce HTT levels are currently being pursued to slow or stop disease progression in people with HD. These approaches are supported by robust preclinical data indicating that reducing variant huntingtin protein is associated with decreased HD pathology. However, the risk-benefit profile of reducing either variant HTT or both variant and wild-type HTT is currently an open question that is being addressed in ongoing clinical trials. This review aims to examine the current data available regarding altered HTT in humans, normal animals, and animal models of HD. Studies indexed in PubMed were searched using the MeSH term Huntington disease or the text words huntington or huntingtin from August 31, 1999, to August 31, 2019, with no language restrictions. Additional studies were included from the reference lists of relevant studies and the authors' personal files. Articles describing at least 1 aspect of HTT reduction were included, prioritizing those published within the last 10 years. In vivo studies were also prioritized, with a focus on studies that examined the consequences of wild-type HTT reduction in adults. In a recently completed phase 1/2a study of RG6042 in 46 adults with early manifest HD, antisense oligonucleotide-mediated partial reduction of HTT was reported to be generally safe and well tolerated over the course of 4-monthly RG6042 doses. In case studies of people with rare genetic variations in huntingtin alleles, the loss of 1 wild-type allele was not associated with HD. People with homozygous cytosine-adenine-guanine expansions developed normally until the onset of HD, although they may have experienced a more aggressive disease course. In mouse models of HD, partial reduction of HTT was beneficial, with improvements in motor, cognitive, and behavioral phenotypes. The partial reduction of wild-type HTT in normal adult rodents and nonhuman primates was generally safe and well tolerated. The body of evidence reviewed in this article indicates a positive risk-benefit profile for the partial reduction of either variant HTT alone or both variant and wild-type HTT. These strategies target the underlying cause of HD and are currently being tested in several investigational clinical trials.
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Affiliation(s)
- Blair R Leavitt
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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Kaemmerer WF, Grondin RC. The effects of huntingtin-lowering: what do we know so far? Degener Neurol Neuromuscul Dis 2019; 9:3-17. [PMID: 30881191 PMCID: PMC6413743 DOI: 10.2147/dnnd.s163808] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Therapies targeting mutant huntingtin DNA, mRNA, and protein have a chance at becoming the first disease-modifying treatments for Huntington’s disease, a fatal inherited neurodegenerative disorder for which only symptom management treatments are available today. This review focuses on evidence addressing several key questions pertinent to huntingtin-lowering, ranging from the functions of wild-type huntingtin (wtHTT) that may be disrupted by huntingtin-lowering treatments through the various ways huntingtin can be lowered, the tolerability of wtHTT-lowering in mice and primates, what has been found in the Ionis Pharmaceutical safety trial of a huntingtin-lowering therapy, and to the question of how much mutant huntingtin may need to be lowered for a therapy to be clinically effective. We conclude that adverse consequences of lowering wtHTT in animals appear to be brain region-specific, and/or dependent upon the animal’s stage of development and the amount by which huntingtin is lowered. Therefore, safe approaches to huntingtin-lowering in patients may be to lower huntingtin only moderately, or lower huntingtin only in the most affected brain regions, or lower huntingtin allele-selectively, or all of the above. Many additional questions about huntingtin-lowering remain open, and will only be answered by upcoming clinical trials, such as whether the delivery approaches currently planned will be adequate to get the treatment to the necessary brain regions, and whether non-allele-selective huntingtin-lowering will be safe in the long run. Meantime, there is a role for preclinical research to address key knowledge gaps, including the effects of non-allele-selective huntingtin-lowering on protein trafficking and viability at the cellular level, the tolerability of wtHTT-lowering in the corticostriatal connections of the primate brain, and the effects of this lowering on the functioning of neurotransmitter systems and the transport of neurotrophic factors to the striatum.
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Affiliation(s)
| | - Richard C Grondin
- Department of Neuroscience, University of Kentucky Medical Center, Lexington, KY, USA,
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10
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Dragatsis I, Dietrich P, Ren H, Deng YP, Del Mar N, Wang HB, Johnson IM, Jones KR, Reiner A. Effect of early embryonic deletion of huntingtin from pyramidal neurons on the development and long-term survival of neurons in cerebral cortex and striatum. Neurobiol Dis 2017; 111:102-117. [PMID: 29274742 PMCID: PMC5821111 DOI: 10.1016/j.nbd.2017.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 11/07/2017] [Accepted: 12/19/2017] [Indexed: 12/12/2022] Open
Abstract
We evaluated the impact of early embryonic deletion of huntingtin (htt) from pyramidal neurons on cortical development, cortical neuron survival and motor behavior, using a cre-loxP strategy to inactivate the mouse htt gene (Hdh) in emx1-expressing cell lineages. Western blot confirmed substantial htt reduction in cerebral cortex of these Emx-httKO mice, with residual cortical htt in all likelihood restricted to cortical interneurons of the subpallial lineage and/or vascular endothelial cells. Despite the loss of htt early in development, cortical lamination was normal, as revealed by layer-specific markers. Cortical volume and neuron abundance were, however, significantly less than normal, and cortical neurons showed reduced brain-derived neurotrophic factor (BDNF) expression and reduced activation of BDNF signaling pathways. Nonetheless, cortical volume and neuron abundance did not show progressive age-related decline in Emx-httKO mice out to 24 months. Although striatal neurochemistry was normal, reductions in striatal volume and neuron abundance were seen in Emx-httKO mice, which were again not progressive. Weight maintenance was normal in Emx-httKO mice, but a slight rotarod deficit and persistent hyperactivity were observed throughout the lifespan. Our results show that embryonic deletion of htt from developing pallium does not substantially alter migration of cortical neurons to their correct laminar destinations, but does yield reduced cortical and striatal size and neuron numbers. The Emx-httKO mice were persistently hyperactive, possibly due to defects in corticostriatal development. Importantly, deletion of htt from cortical pyramidal neurons did not yield age-related progressive cortical or striatal pathology.
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Affiliation(s)
- I Dragatsis
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - P Dietrich
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - H Ren
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Y P Deng
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - N Del Mar
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - H B Wang
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - I M Johnson
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - K R Jones
- Department of Molecular, Cellular, & Developmental Biology, 347 UCB, University of Colorado, Boulder, CO 80309, United States
| | - A Reiner
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States; Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
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11
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Abstract
Huntingtin (HTT) is an essential protein during early embryogenesis and the development of the central nervous system (CNS). Conditional knock-out of mouse Huntingtin (Htt) expression in the CNS beginning during neural development, as well as reducing Htt expression only during embryonic and early postnatal stages, results in neurodegeneration in the adult brain. These findings suggest that HTT is important for the development and/or maintenance of the CNS, but they do not address the question of whether HTT is required specifically in the adult CNS for its normal functions and/or homeostasis. Recently, it was reported that although removing Htt expression in young adult mice causes lethality due to acute pancreatitis, loss of Htt expression in the adult brain is well tolerated and does not result in either motor deficits or neurodegeneration for up to 7 months after Htt inactivation. However, recent studies have also demonstrated that HTT participates in several cellular functions that are important for neuronal homeostasis and survival including sensing reactive oxygen species (ROS), DNA damage repair, and stress responses, in addition to its role in selective macroautophagy. In this review, HTT's functions in development and in the adult CNS will be discussed in the context of these recent discoveries, together with a discussion of their potential impact on the design of therapeutic strategies for Huntington's disease (HD) aimed at lowering total HTT expression.
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Affiliation(s)
| | - Scott O. Zeitlin
- Correspondence to: Scott O. Zeitlin, Ph.D., Department of Neuroscience, University of Virginia School of Medicine, 409 Lane Rd., Box 801392, MR4-5022, Charlottesville, VA 22908, USA. Tel.: +1 434 924 5011; Fax: +1 434 982 4380; E-mail:
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Dietrich P, Johnson IM, Alli S, Dragatsis I. Elimination of huntingtin in the adult mouse leads to progressive behavioral deficits, bilateral thalamic calcification, and altered brain iron homeostasis. PLoS Genet 2017; 13:e1006846. [PMID: 28715425 PMCID: PMC5536499 DOI: 10.1371/journal.pgen.1006846] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 07/31/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
Huntington's Disease (HD) is an autosomal dominant progressive neurodegenerative disorder characterized by cognitive, behavioral and motor dysfunctions. HD is caused by a CAG repeat expansion in exon 1 of the HD gene that is translated into an expanded polyglutamine tract in the encoded protein, huntingtin (HTT). While the most significant neuropathology of HD occurs in the striatum, other brain regions are also affected and play an important role in HD pathology. To date there is no cure for HD, and recently strategies aiming at silencing HTT expression have been initiated as possible therapeutics for HD. However, the essential functions of HTT in the adult brain are currently unknown and hence the consequence of sustained suppression of HTT expression is unpredictable and can potentially be deleterious. Using the Cre-loxP system of recombination, we conditionally inactivated the mouse HD gene homologue at 3, 6 and 9 months of age. Here we show that elimination of Htt expression in the adult mouse results in behavioral deficits, progressive neuropathological changes including bilateral thalamic calcification, and altered brain iron homeostasis.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
| | - Irudayam Maria Johnson
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
| | - Shanta Alli
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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Dale M, Maltby J, Shimozaki S, Cramp R, Rickards H. Disease stage, but not sex, predicts depression and psychological distress in Huntington's disease: A European population study. J Psychosom Res 2016; 80:17-22. [PMID: 26721543 DOI: 10.1016/j.jpsychores.2015.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 11/07/2015] [Accepted: 11/11/2015] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Depression and anxiety significantly affect morbidity in Huntington's disease. Mice. models of Huntington's disease have identified sex differences in mood-like behaviours that vary across disease lifespan, but this interaction has not previously been explored in humans with Huntington's disease. However, among certain medical populations, evidence of sex differences in mood across various disease stages has been found, reflecting trends among the general population that women tend to experience anxiety and depression 1.5 to 2 times more than men. The current study examined whether disease stage and sex, either separately or as an interaction term, predicted anxiety and depression in Huntington's disease. METHODS A cross-sectional study of REGISTRY data involving 453 Huntington's disease participants from 12 European countries was undertaken using the Hospital Anxiety and Depression Scale. A series of multiple regression analyses were undertaken to discover to what extent disease stage and sex predicted anxiety, depression, and general distress after controlling for a number of known predictors of mood difficulties. RESULTS Disease stage, but not sex, was found to predict depressive symptoms and general distress. Neither disease stage nor sex predicted anxiety. Furthermore, an interaction term computed for disease stage and sex did not contribute to the models tested. CONCLUSION In terms of considering risks to developing depression and anxiety in the Huntington's disease population, practitioners may need to pay special attention to disease stage progression (but not sex differences) to enable early detection and treatment of depression (but not anxiety).
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Affiliation(s)
- Maria Dale
- College of Medicine, Biological Sciences and Psychology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, United Kingdom
| | - John Maltby
- College of Medicine, Biological Sciences and Psychology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, United Kingdom.
| | - Steve Shimozaki
- College of Medicine, Biological Sciences and Psychology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, United Kingdom
| | - Rebecca Cramp
- College of Medicine, Biological Sciences and Psychology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, United Kingdom
| | - Hugh Rickards
- College of Medicine, Biological Sciences and Psychology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, United Kingdom
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Wong BKY, Ehrnhoefer DE, Graham RK, Martin DDO, Ladha S, Uribe V, Stanek LM, Franciosi S, Qiu X, Deng Y, Kovalik V, Zhang W, Pouladi MA, Shihabuddin LS, Hayden MR. Partial rescue of some features of Huntington Disease in the genetic absence of caspase-6 in YAC128 mice. Neurobiol Dis 2015; 76:24-36. [PMID: 25583186 DOI: 10.1016/j.nbd.2014.12.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/22/2014] [Accepted: 12/31/2014] [Indexed: 12/13/2022] Open
Abstract
Huntington Disease (HD) is a progressive neurodegenerative disease caused by an elongated CAG repeat in the huntingtin (HTT) gene that encodes a polyglutamine tract in the HTT protein. Proteolysis of the mutant HTT protein (mHTT) has been detected in human and murine HD brains and is implicated in the pathogenesis of HD. Of particular importance is the site at amino acid (aa) 586 that contains a caspase-6 (Casp6) recognition motif. Activation of Casp6 occurs presymptomatically in human HD patients and the inhibition of mHTT proteolysis at aa586 in the YAC128 mouse model results in the full rescue of HD-like phenotypes. Surprisingly, Casp6 ablation in two different HD mouse models did not completely prevent the generation of this fragment, and therapeutic benefits were limited, questioning the role of Casp6 in the disease. We have evaluated the impact of the loss of Casp6 in the YAC128 mouse model of HD. Levels of the mHTT-586 fragment are reduced but not absent in the absence of Casp6 and we identify caspase 8 as an alternate enzyme that can generate this fragment. In vivo, the ablation of Casp6 results in a partial rescue of body weight gain, normalized IGF-1 levels, a reversal of the depression-like phenotype and decreased HTT levels. In the YAC128/Casp6-/- striatum there is a concomitant reduction in p62 levels, a marker of autophagic activity, suggesting increased autophagic clearance. These results implicate the HTT-586 fragment as a key contributor to certain features of HD, irrespective of the enzyme involved in its generation.
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Affiliation(s)
- Bibiana K Y Wong
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada; Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dagmar E Ehrnhoefer
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Rona K Graham
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada; Research Center on Aging, Department of Physiology and Biophysics, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Safia Ladha
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Valeria Uribe
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Lisa M Stanek
- Genzyme, a Sanofi Company, Framingham, MA 01701, USA
| | - Sonia Franciosi
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Xiaofan Qiu
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Yu Deng
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Vlad Kovalik
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Weining Zhang
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Mahmoud A Pouladi
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada; Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, 138648, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 138648, Singapore
| | | | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada.
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Swaminathan A, Kumar M, Halder Sinha S, Schneider-Anthony A, Boutillier AL, Kundu TK. Modulation of neurogenesis by targeting epigenetic enzymes using small molecules: an overview. ACS Chem Neurosci 2014; 5:1164-77. [PMID: 25250644 DOI: 10.1021/cn500117a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Neurogenesis consists of a plethora of complex cellular processes including neural stem cell (NSC) proliferation, migration, maturation or differentiation to neurons, and finally integration into the pre-existing neural circuits in the brain, which are temporally regulated and coordinated sequentially. Mammalian neurogenesis begins during embryonic development and continues in postnatal brain (adult neurogenesis). It is now evident that adult neurogenesis is driven by extracellular and intracellular signaling pathways, where epigenetic modifications like reversible histone acetylation, methylation, as well as DNA methylation play a vital role. Epigenetic regulation of gene expression during neural development is governed mainly by histone acetyltransferases (HATs), histone methyltransferase (HMTs), DNA methyltransferases (DNMTs), and also the enzymes for reversal, like histone deacetylases (HDACs), and many of these have also been shown to be involved in the regulation of adult neurogenesis. The contribution of these epigenetic marks to neurogenesis is increasingly being recognized, through knockout studies and small molecule modulator based studies. These small molecules are directly involved in regeneration and repair of neurons, and not only have applications from a therapeutic point of view, but also provide a tool to study the process of neurogenesis itself. In the present Review, we will focus on small molecules that act predominantly on epigenetic enzymes to enhance neurogenesis and neuroprotection and discuss the mechanism and recent advancements in their synthesis, targeting, and biology.
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Affiliation(s)
- Amrutha Swaminathan
- Transcription and
Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O, Bangalore-560064, India
| | - Manoj Kumar
- Transcription and
Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O, Bangalore-560064, India
| | - Sarmistha Halder Sinha
- Transcription and
Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O, Bangalore-560064, India
| | - Anne Schneider-Anthony
- Laboratoire de Neurosciences
Cognitives et Adaptatives (LNCA), UMR7364, Université de Strasbourg-CNRS,
GDR CNRS 2905, Faculté de Psychologie, 12 rue Goethe, 67000 Strasbourg, France
| | - Anne-Laurence Boutillier
- Laboratoire de Neurosciences
Cognitives et Adaptatives (LNCA), UMR7364, Université de Strasbourg-CNRS,
GDR CNRS 2905, Faculté de Psychologie, 12 rue Goethe, 67000 Strasbourg, France
| | - Tapas K Kundu
- Transcription and
Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O, Bangalore-560064, India
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Pla P, Orvoen S, Saudou F, David DJ, Humbert S. Mood disorders in Huntington's disease: from behavior to cellular and molecular mechanisms. Front Behav Neurosci 2014; 8:135. [PMID: 24795586 PMCID: PMC4005937 DOI: 10.3389/fnbeh.2014.00135] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/03/2014] [Indexed: 01/29/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder that is best known for its effect on motor control. Mood disturbances such as depression, anxiety, and irritability also have a high prevalence in patients with HD, and often start before the onset of motor symptoms. Various rodent models of HD recapitulate the anxiety/depressive behavior seen in patients. HD is caused by an expanded polyglutamine stretch in the N-terminal part of a 350 kDa protein called huntingtin (HTT). HTT is ubiquitously expressed and is implicated in several cellular functions including control of transcription, vesicular trafficking, ciliogenesis, and mitosis. This review summarizes progress in efforts to understand the cellular and molecular mechanisms underlying behavioral disorders in patients with HD. Dysfunctional HTT affects cellular pathways that are involved in mood disorders or in the response to antidepressants, including BDNF/TrkB and serotonergic signaling. Moreover, HTT affects adult hippocampal neurogenesis, a physiological phenomenon that is implicated in some of the behavioral effects of antidepressants and is linked to the control of anxiety. These findings are consistent with the emerging role of wild-type HTT as a crucial component of neuronal development and physiology. Thus, the pathogenic polyQ expansion in HTT could lead to mood disorders not only by the gain of a new toxic function but also by the perturbation of its normal function.
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Affiliation(s)
- Patrick Pla
- Institut Curie Orsay, France ; CNRS UMR3306 Orsay, France ; INSERM U1005 Orsay, France ; Faculté des Sciences, Université Paris-Sud Orsay, France
| | - Sophie Orvoen
- EA3544, Faculté de Pharmacie, Université Paris-Sud Châtenay-Malabry, France
| | - Frédéric Saudou
- Institut Curie Orsay, France ; CNRS UMR3306 Orsay, France ; INSERM U1005 Orsay, France
| | - Denis J David
- EA3544, Faculté de Pharmacie, Université Paris-Sud Châtenay-Malabry, France
| | - Sandrine Humbert
- Institut Curie Orsay, France ; CNRS UMR3306 Orsay, France ; INSERM U1005 Orsay, France
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