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Shafie A, Ashour AA, Anwar S, Anjum F, Hassan MI. Exploring molecular mechanisms, therapeutic strategies, and clinical manifestations of Huntington's disease. Arch Pharm Res 2024:10.1007/s12272-024-01499-w. [PMID: 38764004 DOI: 10.1007/s12272-024-01499-w] [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: 12/18/2023] [Accepted: 05/02/2024] [Indexed: 05/21/2024]
Abstract
Huntington's disease (HD) is a paradigm of a genetic neurodegenerative disorder characterized by the expansion of CAG repeats in the HTT gene. This extensive review investigates the molecular complexities of HD by highlighting the pathogenic mechanisms initiated by the mutant huntingtin protein. Adverse outcomes of HD include mitochondrial dysfunction, compromised protein clearance, and disruption of intracellular signaling, consequently contributing to the gradual deterioration of neurons. Numerous therapeutic strategies, particularly precision medicine, are currently used for HD management. Antisense oligonucleotides, such as Tominersen, play a leading role in targeting and modulating the expression of mutant huntingtin. Despite the promise of these therapies, challenges persist, particularly in improving delivery systems and the necessity for long-term safety assessments. Considering the future landscape, the review delineates promising directions for HD research and treatment. Innovations such as Clustered regularly interspaced short palindromic repeats associated system therapies (CRISPR)-based genome editing and emerging neuroprotective approaches present unprecedented opportunities for intervention. Collaborative interdisciplinary endeavors and a more insightful understanding of HD pathogenesis are on the verge of reshaping the therapeutic landscape. As we navigate the intricate landscape of HD, this review serves as a guide for unraveling the intricacies of this disease and progressing toward transformative treatments.
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Affiliation(s)
- Alaa Shafie
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, PO Box 11099, 21944, Taif, Saudi Arabia
| | - Amal Adnan Ashour
- Department of Oral and Maxillofacial Surgery and Diagnostic Sciences, Faculty of Dentistry, Taif University, PO Box 11099, 21944, Taif, Saudi Arabia
| | - Saleha Anwar
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Farah Anjum
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, PO Box 11099, 21944, Taif, Saudi Arabia
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India.
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2
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Cheng Y, Zhang S, Shang H. Latest advances on new promising molecular-based therapeutic approaches for Huntington's disease. J Transl Int Med 2024; 12:134-147. [PMID: 38779119 PMCID: PMC11107186 DOI: 10.2478/jtim-2023-0142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024] Open
Abstract
Huntington's disease (HD) is a devastating, autosomal-dominant inherited, neurodegenerative disorder characterized by progressive motor deficits, cognitive impairments, and neuropsychiatric symptoms. It is caused by excessive cytosine-adenine-guanine (CAG) trinucleotide repeats within the huntingtin gene (HTT). Presently, therapeutic interventions capable of altering the trajectory of HD are lacking, while medications for abnormal movement and psychiatric symptoms are limited. Numerous pre-clinical and clinical studies have been conducted and are currently underway to test the efficacy of therapeutic approaches targeting some of these mechanisms with varying degrees of success. In this review, we update the latest advances on new promising molecular-based therapeutic strategies for this disorder, including DNA-targeting techniques such as zinc-finger proteins, transcription activator-like effector nucleases, and CRISPR/Cas9; post-transcriptional huntingtin-lowering approaches such as RNAi, antisense oligonucleotides, and small-molecule splicing modulators; and novel methods to clear the mHTT protein, such as proteolysis-targeting chimeras. We mainly focus on the ongoing clinical trials and the latest pre-clinical studies to explore the progress of emerging potential HD therapeutics.
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Affiliation(s)
- Yangfan Cheng
- Department of Neurology, Laboratory of Neurodegenerative Disorders, Rare disease center, West China Hospital, Sichuan University, Chengdu610041, Sichuan Province, China
| | - Sirui Zhang
- Department of Neurology, Laboratory of Neurodegenerative Disorders, Rare disease center, West China Hospital, Sichuan University, Chengdu610041, Sichuan Province, China
| | - Huifang Shang
- Department of Neurology, Laboratory of Neurodegenerative Disorders, Rare disease center, West China Hospital, Sichuan University, Chengdu610041, Sichuan Province, China
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3
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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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4
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Caron NS, Aly AEE, Findlay Black H, Martin DDO, Schmidt ME, Ko S, Anderson C, Harvey EM, Casal LL, Anderson LM, Rahavi SMR, Reid GSD, Oda MN, Stanimirovic D, Abulrob A, McBride JL, Leavitt BR, Hayden MR. Systemic delivery of mutant huntingtin lowering antisense oligonucleotides to the brain using apolipoprotein A-I nanodisks for Huntington disease. J Control Release 2024; 367:27-44. [PMID: 38215984 DOI: 10.1016/j.jconrel.2024.01.011] [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: 08/13/2023] [Revised: 12/09/2023] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
Efficient delivery of therapeutics to the central nervous system (CNS) remains a major challenge for the treatment of neurological diseases. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion mutation in the HTT gene which codes for a toxic mutant huntingtin (mHTT) protein. Pharmacological reduction of mHTT in the CNS using antisense oligonucleotides (ASO) ameliorates HD-like phenotypes in rodent models of HD, with such therapies being investigated in clinical trials for HD. In this study, we report the optimization of apolipoprotein A-I nanodisks (apoA-I NDs) as vehicles for delivery of a HTT-targeted ASO (HTT ASO) to the brain and peripheral organs for HD. We demonstrate that apoA-I wild type (WT) and the apoA-I K133C mutant incubated with a synthetic lipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine, can self-assemble into monodisperse discoidal particles with diameters <20 nm that transmigrate across an in vitro blood-brain barrier model of HD. We demonstrate that apoA-I NDs are well tolerated in vivo, and that apoA-I K133C NDs show enhanced distribution to the CNS and peripheral organs compared to apoA-I WT NDs following systemic administration. ApoA-I K133C conjugated with HTT ASO forms NDs (HTT ASO NDs) that induce significant mHTT lowering in the liver, skeletal muscle and heart as well as in the brain when delivered intravenously in the BACHD mouse model of HD. Furthermore, HTT ASO NDs increase the magnitude of mHTT lowering in the striatum and cortex compared to HTT ASO alone following intracerebroventricular administration. These findings demonstrate the potential utility of apoA-I NDs as biocompatible vehicles for enhancing delivery of mutant HTT lowering ASOs to the CNS and peripheral organs for HD.
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Affiliation(s)
- Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amirah E-E Aly
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada; Department of Biology, University of Waterloo, Ontario, Canada
| | - Mandi E Schmidt
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Seunghyun Ko
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Christine Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Emily M Harvey
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Lorenzo L Casal
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Lisa M Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Seyed M R Rahavi
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregor S D Reid
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Danica Stanimirovic
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Abedelnasser Abulrob
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Jodi L McBride
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA; Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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5
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Hett K, Eisma JJ, Hernandez AB, McKnight CD, Song A, Elenberger J, Considine C, Donahue MJ, Claassen DO. Cerebrospinal Fluid Flow in Patients with Huntington's Disease. Ann Neurol 2023; 94:885-894. [PMID: 37493342 PMCID: PMC10615133 DOI: 10.1002/ana.26749] [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: 04/16/2023] [Revised: 07/08/2023] [Accepted: 07/17/2023] [Indexed: 07/27/2023]
Abstract
OBJECTIVE Investigations of cerebrospinal fluid (CSF) flow aberrations in Huntington's disease (HD) are of growing interest, as impaired CSF flow may contribute to mutant Huntington retention and observed heterogeneous responsiveness to intrathecally administered therapies. METHOD We assessed net cerebral aqueduct CSF flow and velocity in 29 HD participants (17 premanifest and 12 manifest) and 51 age- and sex matched non-HD control participants using 3-Tesla magnetic resonance imaging methods. Regression models were applied to test hypotheses regarding: (i) net CSF flow and cohort, (ii) net CSF flow and disease severity (CAP-score), and (iii) CSF volume after correcting for age and sex. RESULTS Group-wise analyses support a decrease in net CSF flow in HD (mean 0.14 ± 0.27 mL/min) relative to control (mean 0.32 ± 0.20 mL/min) participants (p = 0.02), with lowest flow in the manifest HD cohort (mean 0.04 ± 0.25 mL/min). This finding was explained by hyperdynamic CSF movement, manifesting as higher caudal systolic CSF flow velocity and higher diastolic cranial CSF flow velocity across the cardiac cycle, in HD (caudal flow: 0.17 ± 0.07 mL/s, cranial flow: 0.14 ± 0.08 mL/s) compared to control (caudal flow: 0.13 ± 0.06 mL/s, cranial flow: 0.11 ± 0.04 mL/s) participants. A positive correlation between cranial diastolic flow and disease severity was observed (p = 0.02). INTERPRETATIONS Findings support aqueductal CSF flow dynamics changing with disease severity in HD. These accelerated changes are consistent with changes observed over the typical adult lifespan, and may have relevance to mutant Huntington retention and intrathecally administered therapeutics responsiveness. ANN NEUROL 2023;94:885-894.
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Affiliation(s)
- Kilian Hett
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jarrod J. Eisma
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Colin D. McKnight
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alexander Song
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jason Elenberger
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ciaran Considine
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Manus J. Donahue
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Daniel O. Claassen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
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6
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Shing K, Sapp E, Boudi A, Liu S, Seeley C, Marchionini D, DiFiglia M, Kegel-Gleason KB. Early whole-body mutant huntingtin lowering averts changes in proteins and lipids important for synapse function and white matter maintenance in the LacQ140 mouse model. Neurobiol Dis 2023; 187:106313. [PMID: 37777020 PMCID: PMC10731584 DOI: 10.1016/j.nbd.2023.106313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 10/02/2023] Open
Abstract
Expansion of a triplet repeat tract in exon 1 of the HTT gene causes Huntington's disease (HD). The mutant HTT protein (mHTT) has numerous aberrant interactions with diverse, pleiomorphic effects. Lowering mHTT is a promising approach to treat HD, but it is unclear when lowering should be initiated, how much is necessary, and what duration should occur to achieve benefits. Furthermore, the effects of mHTT lowering on brain lipids have not been assessed. Using a mHtt-inducible mouse model, we analyzed mHtt lowering initiated at different ages and sustained for different time-periods. mHTT protein in cytoplasmic and synaptic compartments of the striatum was reduced 38-52%; however, there was minimal lowering of mHTT in nuclear and perinuclear regions where aggregates formed at 12 months of age. Total striatal lipids were reduced in 9-month-old LacQ140 mice and preserved by mHtt lowering. Subclasses important for white matter structure and function including ceramide (Cer), sphingomyelin (SM), and monogalactosyldiacylglycerol (MGDG), contributed to the reduction in total lipids. Phosphatidylinositol (PI), phosphatidylserine (PS), and bismethyl phosphatidic acid (BisMePA) were also changed in LacQ140 mice. Levels of all subclasses except ceramide were preserved by mHtt lowering. mRNA expression profiling indicated that a transcriptional mechanism contributes to changes in myelin lipids, and some but not all changes can be prevented by mHtt lowering. Our findings suggest that early and sustained reduction in mHtt can prevent changes in levels of select striatal proteins and most lipids, but a misfolded, degradation-resistant form of mHTT hampers some benefits in the long term.
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Affiliation(s)
- Kai Shing
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Adel Boudi
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Sophia Liu
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Connor Seeley
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | | | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
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7
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Liu L, Malagu K, Haughan AF, Khetarpal V, Stott AJ, Esmieu W, Vater HD, Webster SJ, Van de Poël AJ, Clissold C, Cosgrove B, Sutton B, Spencer JA, Breccia P, Gancia E, Bonomo S, Ladduwahetty T, Lazari O, Patel H, Atton HC, Clifton S, Mota DM, Magnani D, O'Neill A, Stebbeds M, Macabuag N, Todd D, Herva ME, Mitchell P, Visser M, Compte Sancerni S, Grand Moursel L, da Silva M, Kritikou E, Heikkinen TT, Bolkvadze T, Fodale V, Spadafora D, Daldin M, Bresciani A, Mangette JE, Doherty EM, Lee MR, Herbst T, Monteagudo E, Macdonald D, Plotnikov NV, Chambers M, McAllister G, Muňoz-Sanjuan I, Dominguez C. Identification and Optimization of RNA-Splicing Modulators as Huntingtin Protein-Lowering Agents for the Treatment of Huntington's Disease. J Med Chem 2023; 66:13205-13246. [PMID: 37712656 DOI: 10.1021/acs.jmedchem.3c01173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat in exon 1 of the huntingtin (HTT) gene. We report the design of a series of HTT pre-mRNA splicing modulators that lower huntingtin (HTT) protein, including the toxic mutant huntingtin (mHTT), by promoting insertion of a pseudoexon containing a premature termination codon at the exon 49-50 junction. The resulting transcript undergoes nonsense-mediated decay, leading to a reduction of HTT mRNA transcripts and protein levels. The starting benzamide core was modified to pyrazine amide and further optimized to give a potent, CNS-penetrant, and orally bioavailable HTT-splicing modulator 27. This compound reduced canonical splicing of the HTT RNA exon 49-50 and demonstrated significant HTT-lowering in both human HD stem cells and mouse BACHD models. Compound 27 is a structurally diverse HTT-splicing modulator that may help understand the mechanism of adverse effects such as peripheral neuropathy associated with branaplam.
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Affiliation(s)
- Longbin Liu
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Karine Malagu
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Alan F Haughan
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Vinod Khetarpal
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Andrew J Stott
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - William Esmieu
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Huw D Vater
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Stephen J Webster
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Amanda J Van de Poël
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Cole Clissold
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Brett Cosgrove
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Benjamin Sutton
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Jonathan A Spencer
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Perla Breccia
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Emanuela Gancia
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Silvia Bonomo
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Tammy Ladduwahetty
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Ovadia Lazari
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Hiral Patel
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Helen C Atton
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Steve Clifton
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Daniel M Mota
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Dario Magnani
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Amy O'Neill
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Marta Stebbeds
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Natsuko Macabuag
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Daniel Todd
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Maria E Herva
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Philip Mitchell
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - Mijke Visser
- Charles River, Darwinweg 24, 2333 CR Leiden, The Netherlands
| | | | | | - Marta da Silva
- Charles River, Darwinweg 24, 2333 CR Leiden, The Netherlands
| | - Eva Kritikou
- Charles River, Darwinweg 24, 2333 CR Leiden, The Netherlands
| | | | | | | | | | | | | | | | - Elizabeth M Doherty
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Matthew R Lee
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Todd Herbst
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Edith Monteagudo
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Douglas Macdonald
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Nikolay V Plotnikov
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Mark Chambers
- Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K
| | - George McAllister
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Ignacio Muňoz-Sanjuan
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
| | - Celia Dominguez
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States
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8
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Li SH, Colson TLL, Chen J, Abd-Elrahman KS, Ferguson SSG. Comparison of Huntington's disease phenotype progression in male and female heterozygous FDNQ175 mice. Mol Brain 2023; 16:67. [PMID: 37726802 PMCID: PMC10508000 DOI: 10.1186/s13041-023-01054-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/06/2023] [Indexed: 09/21/2023] Open
Abstract
Huntington's Disease (HD) is an inherited autosomal dominant neurodegenerative disorder that leads to progressive motor and cognitive impairment due to the expansion of a polyglutamine (CAG) repeat in the N-terminal region of the huntingtin (Htt) protein. The creation of HD mouse models represents a critical step in the research for HD treatment. Among the currently available HD mouse models, the zQ175 knock-in mouse line is the first to display robust disease phenotype on a heterozygous background. The newer FDNQ175 mouse model is derived from the zQ175 mouse line and presents a more aggressive phenotype. Moreover, increasing evidence has implicated sex as a contributing factor in the progression of HD symptoms. Here, we compared the progression of HD phenotypes in male and female heterozygous FDNQ175 mice. We found that both male and female heterozygous mice showed deficits in forelimb grip strength and cognition as early as 6 months of age. However, female FDNQ175 mice were less vulnerable to HD-associated decline in limb coordination and movement. Neither male nor female FDNQ175 mice exhibited reduced locomotor activity in the open field or exhibit consistent differences in anxiety at 6-12 months of age. Both male and female FDNQ175 mice exhibited increased numbers of huntingtin aggregates with age and 8-month-old female FDNQ175 mice had significantly more aggregates than their male counterparts. Taken together, our results provide further evidence that sex can influence the progression of HD phenotype in preclinical animal models and must be taken into consideration for future HD research.
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Affiliation(s)
- Si Han Li
- University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Tash-Lynn L Colson
- University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Jingwei Chen
- University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Khaled S Abd-Elrahman
- Department of Anesthesiology, Pharmacology and Therapeutics, and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- Department of Pharmacology and Therapeutics, College of Medicine and Health Science, Khalifa University, Abu Dhabi, United Arab Emirates
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt
| | - Stephen S G Ferguson
- University of Ottawa Brain and Mind Research Institute, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
- Department of Neuroscience, Faculty of Health Sciences, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada.
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9
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Aly AEE, Caron NS, Black HF, Schmidt ME, Anderson C, Ko S, Baddeley HJE, Anderson L, Casal LL, Rahavi RSM, Martin DDO, Hayden MR. Delivery of mutant huntingtin-lowering antisense oligonucleotides to the brain by intranasally administered apolipoprotein A-I nanodisks. J Control Release 2023; 360:913-927. [PMID: 37468110 DOI: 10.1016/j.jconrel.2023.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/12/2023] [Accepted: 07/15/2023] [Indexed: 07/21/2023]
Abstract
Lowering mutant huntingtin (mHTT) in the central nervous system (CNS) using antisense oligonucleotides (ASOs) is a promising approach currently being evaluated in clinical trials for Huntington disease (HD). However, the therapeutic potential of ASOs in HD patients is limited by their inability to cross the blood-brain barrier (BBB). In non-human primates, intrathecal infusion of ASOs results in limited brain distribution, with higher ASO concentrations in superficial regions and lower concentrations in deeper regions, such as the basal ganglia. To address the need for improved delivery of ASOs to the brain, we are evaluating the therapeutic potential of apolipoprotein A-I nanodisks (apoA-I NDs) as novel delivery vehicles for mHTT-lowering ASOs to the CNS after intranasal administration. Here, we have demonstrated the ability of apoA-I nanodisks to bypass the BBB after intranasal delivery in the BACHD model of HD. Following intranasal administration of apoA-I NDs, apoA-I protein levels were elevated along the rostral-caudal brain axis, with highest levels in the most rostral brain regions including the olfactory bulb and frontal cortex. Double-label immunohistochemistry indicates that both the apoA-I and ASO deposit in neurons. Most importantly, a single intranasal dose of apoA-I ASO-NDs significantly reduces mHTT levels in the brain regions most affected in HD, namely the cortex and striatum. This approach represents a novel non-invasive means for improving delivery and brain distribution of oligonucleotide therapies and enhancing likelihood of efficacy. Improved ASO delivery to the brain has widespread application for treatment of many other CNS disorders.
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Affiliation(s)
- Amirah E-E Aly
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Mandi E Schmidt
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Christine Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC V5Z 4H4, Canada
| | - Seunghyun Ko
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC V5Z 4H4, Canada
| | - Helen J E Baddeley
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC V5Z 4H4, Canada
| | - Lisa Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC V5Z 4H4, Canada
| | - Lorenzo L Casal
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC V5Z 4H4, Canada
| | - Reza S M Rahavi
- Michael Cuccione Childhood Cancer Research Program, British Columbia Children's a Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada; Department of Biology, University of Waterloo, Ontario, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada.
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10
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Shing K, Sapp E, Boudi A, Liu S, Seeley C, Marchionini D, DiFiglia M, Kegel-Gleason KB. Early whole-body mutant huntingtin lowering averts changes in proteins and lipids important for synapse function and white matter maintenance in the LacQ140 mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525697. [PMID: 36747614 PMCID: PMC9900921 DOI: 10.1101/2023.01.26.525697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Expansion of a triplet repeat tract in exon1 of the HTT gene causes Huntington's disease (HD). The mutant HTT protein (mHTT) has numerous aberrant interactions with diverse, pleiomorphic effects. No disease modifying treatments exist but lowering mutant huntingtin (mHTT) by gene therapy is a promising approach to treat Huntington's disease (HD). It is not clear when lowering should be initiated, how much lowering is necessary and for what duration lowering should occur to achieve benefits. Furthermore, the effects of mHTT lowering on brain lipids have not been assessed. Using a mHtt-inducible mouse model we analyzed whole body mHtt lowering initiated at different ages and sustained for different time-periods. Subcellular fractionation (density gradient ultracentrifugation), protein chemistry (gel filtration, western blot, and capillary electrophoresis immunoassay), liquid chromatography and mass spectrometry of lipids, and bioinformatic approaches were used to test effects of mHTT transcriptional lowering. mHTT protein in cytoplasmic and synaptic compartments of the caudate putamen, which is most affected in HD, was reduced 38-52%. Little or no lowering of mHTT occurred in nuclear and perinuclear regions where aggregates formed at 12 months of age. mHtt transcript repression partially or fully preserved select striatal proteins (SCN4B, PDE10A). Total lipids in striatum were reduced in LacQ140 mice at 9 months and preserved by early partial mHtt lowering. The reduction in total lipids was due in part to reductions in subclasses of ceramide (Cer), sphingomyelin (SM), and monogalactosyldiacylglycerol (MGDG), which are known to be important for white matter structure and function. Lipid subclasses phosphatidylinositol (PI), phosphatidylserine (PS), and bismethyl phosphatidic acid (BisMePA) were also changed in LacQ140 mice. Levels of all subclasses other than ceramide were preserved by early mHtt lowering. Pathway enrichment analysis of RNAseq data imply a transcriptional mechanism is responsible in part for changes in myelin lipids, and some but not all changes can be rescued by mHTT lowering. Our findings suggest that early and sustained reduction in mHtt can prevent changes in levels of select striatal proteins and most lipids but a misfolded, degradation-resistant form of mHTT hampers some benefits in the long term.
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Affiliation(s)
- Kai Shing
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129
| | - Adel Boudi
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129
| | - Sophia Liu
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129
| | - Connor Seeley
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129
| | | | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129
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11
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Polikarpova AV, Egorova TV, Lunev EA, Tsitrina AA, Vassilieva SG, Savchenko IM, Silaeva YY, Deykin AV, Bardina MV. CRISPR/Cas9-generated mouse model with humanizing single-base substitution in the Gnao1 for safety studies of RNA therapeutics. Front Genome Ed 2023; 5:1034720. [PMID: 37077890 PMCID: PMC10106585 DOI: 10.3389/fgeed.2023.1034720] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 03/20/2023] [Indexed: 04/05/2023] Open
Abstract
The development of personalized medicine for genetic diseases requires preclinical testing in the appropriate animal models. GNAO1 encephalopathy is a severe neurodevelopmental disorder caused by heterozygous de novo mutations in the GNAO1 gene. GNAO1 c.607 G>A is one of the most common pathogenic variants, and the mutant protein Gαo-G203R likely adversely affects neuronal signaling. As an innovative approach, sequence-specific RNA-based therapeutics such as antisense oligonucleotides or effectors of RNA interference are potentially applicable for selective suppression of the mutant GNAO1 transcript. While in vitro validation can be performed in patient-derived cells, a humanized mouse model to rule out the safety of RNA therapeutics is currently lacking. In the present work, we employed CRISPR/Cas9 technology to introduce a single-base substitution into exon 6 of the Gnao1 to replace the murine Gly203-coding triplet (GGG) with the codon used in the human gene (GGA). We verified that genome-editing did not interfere with the Gnao1 mRNA or Gαo protein synthesis and did not alter localization of the protein in the brain structures. The analysis of blastocysts revealed the off-target activity of the CRISPR/Cas9 complexes; however, no modifications of the predicted off-target sites were detected in the founder mouse. Histological staining confirmed the absence of abnormal changes in the brain of genome-edited mice. The created mouse model with the “humanized” fragment of the endogenous Gnao1 is suitable to rule out unintended targeting of the wild-type allele by RNA therapeutics directed at lowering GNAO1 c.607 G>A transcripts.
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Affiliation(s)
- Anna V. Polikarpova
- Laboratory of Modeling and Gene Therapy of Hereditary Diseases, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Marlin Biotech, Sochi, Russia
| | - Tatiana V. Egorova
- Laboratory of Modeling and Gene Therapy of Hereditary Diseases, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Marlin Biotech, Sochi, Russia
| | - Evgenii A. Lunev
- Laboratory of Modeling and Gene Therapy of Hereditary Diseases, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Marlin Biotech, Sochi, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Alexandra A. Tsitrina
- Koltzov Institute of Developmental Biology Russian Academy of Sciences, Moscow, Russia
| | - Svetlana G. Vassilieva
- Laboratory of Modeling and Gene Therapy of Hereditary Diseases, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Marlin Biotech, Sochi, Russia
| | - Irina M. Savchenko
- Marlin Biotech, Sochi, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Yuliya Y. Silaeva
- Core Facility Center, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Alexey V. Deykin
- Marlin Biotech, Sochi, Russia
- Core Facility Center, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Laboratory of Genetic Technologies and Genome Editing for Biomedicine and Animal Health, Joint Center for Genetic Technologies, Belgorod National Research University, Belgorod, Russia
| | - Maryana V. Bardina
- Laboratory of Modeling and Gene Therapy of Hereditary Diseases, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Marlin Biotech, Sochi, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- *Correspondence: Maryana V. Bardina,
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12
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Dindot SV, Christian S, Murphy WJ, Berent A, Panagoulias J, Schlafer A, Ballard J, Radeva K, Robinson R, Myers L, Jepp T, Shaheen H, Hillman P, Konganti K, Hillhouse A, Bredemeyer KR, Black L, Douville J. An ASO therapy for Angelman syndrome that targets an evolutionarily conserved region at the start of the UBE3A-AS transcript. Sci Transl Med 2023; 15:eabf4077. [PMID: 36947593 DOI: 10.1126/scitranslmed.abf4077] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Angelman syndrome is a devastating neurogenetic disorder for which there is currently no effective treatment. It is caused by mutations or epimutations affecting the expression or function of the maternally inherited allele of the ubiquitin-protein ligase E3A (UBE3A) gene. The paternal UBE3A allele is imprinted in neurons of the central nervous system (CNS) by the UBE3A antisense (UBE3A-AS) transcript, which represents the distal end of the small nucleolar host gene 14 (SNHG14) transcription unit. Reactivating the expression of the paternal UBE3A allele in the CNS has long been pursued as a therapeutic option for Angelman syndrome. Here, we described the development of an antisense oligonucleotide (ASO) therapy for Angelman syndrome that targets an evolutionarily conserved region demarcating the start of the UBE3A-AS transcript. We designed and chemically optimized gapmer ASOs targeting specific sequences at the start of the human UBE3A-AS transcript. We showed that ASOs targeting this region precisely and efficiently repress the transcription of UBE3A-AS, reactivating the expression of the paternal UBE3A allele in neurotypical and Angelman syndrome induced pluripotent stem cell-derived neurons. We further showed that human-targeted ASOs administered to the CNS of cynomolgus macaques by lumbar intrathecal injection repress UBE3A-AS and reactivate the expression of the paternal UBE3A allele throughout the CNS. These findings support the advancement of this investigational molecular therapy for Angelman syndrome into clinical development (ClinicalTrials.gov, NCT04259281).
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Affiliation(s)
- Scott V Dindot
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University, College Station, TX 77843, USA
- GeneTx Biotherapeutics LLC, Sarasota, FL 34233, USA
- Research Department, Ultragenyx Pharmaceutical, Novato, CA 94949, USA
| | - Sarah Christian
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - William J Murphy
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | | | | | - Annalise Schlafer
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Johnathan Ballard
- Texas A&M Institute for Genomic Medicine (TIGM), Texas A&M University, College Station, TX 77843, USA
| | - Kamelia Radeva
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
- School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK
| | - Ruth Robinson
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
- School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK
| | - Luke Myers
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
- School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK
| | - Thomas Jepp
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
- School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK
| | - Hillary Shaheen
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Paul Hillman
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Kranti Konganti
- Texas A&M University Institute for Genome Sciences and Society (TIGSS), Texas A&M University, College Station, TX 77843, USA
| | - Andrew Hillhouse
- Texas A&M University Institute for Genome Sciences and Society (TIGSS), Texas A&M University, College Station, TX 77843, USA
| | - Kevin R Bredemeyer
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | | | - Julie Douville
- Charles River Laboratories, Montreal, Senneville, Quebec H9X 1C1, Canada
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13
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Therapeutic targeting of Huntington's disease: Molecular and clinical approaches. Biochem Biophys Res Commun 2023; 655:18-24. [PMID: 36913762 DOI: 10.1016/j.bbrc.2023.02.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/26/2023] [Indexed: 03/09/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant ailment that affects a larger population. Due to its complex pathology operating at DNA, RNA, and protein levels, it is regarded as a protein-misfolding disease and an expansion repeat disorder. Despite the availability of early genetic diagnostics, disease-modifying treatments are still missing. Importantly, potential therapies are starting to make their way through clinical trials. Still, clinical trials are ongoing to discover potential drugs to relieve HD symptoms. However, now being aware of the root cause, the clinical studies are focused on molecular therapies to target it. The road to success has not been without bumps since a big phase III trial of tominersen was unexpectedly discontinued due to exceeding risks than drug's benefit to the patients. Although the trial's conclusion was disappointing, there is still cause to be optimistic about what this technique may achieve. We have reviewed the present disease-modifying therapies in clinical development for HD and examined the current landscape of developing clinical therapies. We further investigated the pharmaceutical development of Huntington's medicine in the pharma industries and addressed the existing challenges in their therapeutic success.
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14
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Cas9-mediated replacement of expanded CAG repeats in a pig model of Huntington's disease. Nat Biomed Eng 2023; 7:629-646. [PMID: 36797418 DOI: 10.1038/s41551-023-01007-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 01/20/2023] [Indexed: 02/18/2023]
Abstract
The monogenic nature of Huntington's disease (HD) and other neurodegenerative diseases caused by the expansion of glutamine-encoding CAG repeats makes them particularly amenable to gene therapy. Here we show the feasibility of replacing expanded CAG repeats in the mutant HTT allele with a normal CAG repeat in genetically engineered pigs mimicking the selective neurodegeneration seen in patients with HD. A single intracranial or intravenous injection of adeno-associated virus encoding for Cas9, a single-guide RNA targeting the HTT gene, and donor DNA containing the normal CAG repeat led to the depletion of mutant HTT in the animals and to substantial reductions in the dysregulated expression and neurotoxicity of mutant HTT and in neurological symptoms. Our findings support the further translational development of virally delivered Cas9-based gene therapies for the treatment of genetic neurodegenerative diseases.
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15
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Cyclodextrin-Based Nanoparticles for Delivery of Antisense Oligonucleotides Targeting Huntingtin. Pharmaceutics 2023; 15:pharmaceutics15020520. [PMID: 36839842 PMCID: PMC9965918 DOI: 10.3390/pharmaceutics15020520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 02/02/2023] [Indexed: 02/09/2023] Open
Abstract
Huntington's disease (HD) is a progressive inherited neurodegenerative disease caused by a CAG repeat expansion in the huntingtin gene, which is translated into the pathologic mutant huntingtin (mHTT) protein. Despite the great potential of HTT lowering strategies and the numerous antisense oligonucleotides (ASOs) in pre- and clinical trials, sustained silencing of mHTT has not been achieved. As a strategy to improve ASO delivery, cyclodextrin-based nanoparticles (CDs) offer a promising approach. Here, three CDs with distinct chemical structures were designed and their efficacies were compared as potential platforms for the delivery of ASO targeting HTT. Results using striatal neurons and HD patient-derived fibroblasts indicate that modified γ-CDs exhibited the best uptake efficiency and successfully downregulated mHTT at protein and allele levels. The incorporation of the brain-targeting peptide RVG into the modified γ-CDs showed greater downregulation of mHTT protein and HD-causing allele SNP1 than untargeted ones in an in vitro blood-brain barrier model. Although the ASO sequence was designed as a nonallele-specific therapeutic approach, our strategy gives an additional benefit of some mHTT selectivity. Overall, this study demonstrated the CD platform's feasibility for delivering ASO-based therapeutics for HD treatment.
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16
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Lim CK, McCallister TX, Saporito-Magriña C, McPheron GD, Krishnan R, Zeballos C MA, Powell JE, Clark LV, Perez-Pinera P, Gaj T. CRISPR base editing of cis-regulatory elements enables the perturbation of neurodegeneration-linked genes. Mol Ther 2022; 30:3619-3631. [PMID: 35965414 PMCID: PMC9734028 DOI: 10.1016/j.ymthe.2022.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/25/2022] [Accepted: 08/09/2022] [Indexed: 12/15/2022] Open
Abstract
CRISPR technology has demonstrated broad utility for controlling target gene expression; however, there remains a need for strategies capable of modulating expression via the precise editing of non-coding regulatory elements. Here, we demonstrate that CRISPR base editors, a class of gene-modifying proteins capable of creating single-base substitutions in DNA, can be used to perturb gene expression via their targeted mutagenesis of cis-acting sequences. Using the promoter region of the human huntingtin (HTT) gene as an initial target, we show that editing of the binding site for the transcription factor NF-κB led to a marked reduction in HTT gene expression in base-edited cell populations. We found that these gene perturbations were persistent and specific, as a transcriptome-wide RNA analysis revealed minimal off-target effects resulting from the action of the base editor protein. We further demonstrate that this base-editing platform could influence gene expression in vivo as its delivery to a mouse model of Huntington's disease led to a potent decrease in HTT mRNA in striatal neurons. Finally, to illustrate the applicability of this concept, we target the amyloid precursor protein, showing that multiplex editing of its promoter region significantly perturbed its expression. These findings demonstrate the potential for base editors to regulate target gene expression.
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Affiliation(s)
- Colin K.W. Lim
- Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA
| | | | | | | | - Ramya Krishnan
- Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA
| | | | - Jackson E. Powell
- Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA
| | - Lindsay V. Clark
- Roy J. Carver Biotechnology Center, University of Illinois, Urbana, IL 61801, USA
| | - Pablo Perez-Pinera
- Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA,Department of Biomedical and Translational Sciences, Carle-Illinois College of Medicine, University of Illinois, Urbana, IL 61801, USA,Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA,Corresponding author: Pablo Perez-Pinera, Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA.
| | - Thomas Gaj
- Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA,Corresponding author: Thomas Gaj, Department of Bioengineering, University of Illinois, Urbana, IL 61801, USA.
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17
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Robillard KN, de Vrieze E, van Wijk E, Lentz JJ. Altering gene expression using antisense oligonucleotide therapy for hearing loss. Hear Res 2022; 426:108523. [PMID: 35649738 DOI: 10.1016/j.heares.2022.108523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/20/2022] [Accepted: 05/14/2022] [Indexed: 12/12/2022]
Abstract
Hearing loss affects more than 430 million people, worldwide, and is the third most common chronic physical condition in the United States and Europe (GBD Hearing Loss Collaborators, 2021; NIOSH, 2021; WHO, 2021). The loss of hearing significantly impacts motor and cognitive development, communication, education, employment, and overall quality of life. The inner ear houses the sensory organs for both hearing and balance and provides an accessible target for therapeutic delivery. Antisense oligonucleotides (ASOs) use various mechanisms to manipulate gene expression and can be tailor-made to treat disorders with defined genetic targets. In this review, we discuss the preclinical advancements within the field of the highly promising ASO-based therapies for hereditary hearing loss disorders. Particular focus is on ASO mechanisms of action, preclinical studies on ASO treatments of hearing loss, timing of therapeutic intervention, and delivery routes to the inner ear.
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Affiliation(s)
| | - Erik de Vrieze
- Department of Otorhinolaryngology, RUMC, Geert Grooteplein 10, Route 855, GA, Nijmegen 6525, the Netherlands; Donders Institute for Brain, Cognition, and Behavior, RUMC, Nijmegen, NL
| | - Erwin van Wijk
- Department of Otorhinolaryngology, RUMC, Geert Grooteplein 10, Route 855, GA, Nijmegen 6525, the Netherlands; Donders Institute for Brain, Cognition, and Behavior, RUMC, Nijmegen, NL.
| | - Jennifer J Lentz
- Neuroscience Center of Excellence, LSUHSC, New Orleans, LA, USA; Department of Otorhinolaryngology, LSUHSC, 2020 Gravier Street, Lions Building, Room 795, New Orleans, LA, USA.
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18
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Conroy F, Miller R, Alterman JF, Hassler MR, Echeverria D, Godinho BMDC, Knox EG, Sapp E, Sousa J, Yamada K, Mahmood F, Boudi A, Kegel-Gleason K, DiFiglia M, Aronin N, Khvorova A, Pfister EL. Chemical engineering of therapeutic siRNAs for allele-specific gene silencing in Huntington's disease models. Nat Commun 2022; 13:5802. [PMID: 36192390 PMCID: PMC9530163 DOI: 10.1038/s41467-022-33061-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 08/31/2022] [Indexed: 11/23/2022] Open
Abstract
Small interfering RNAs are a new class of drugs, exhibiting sequence-driven, potent, and sustained silencing of gene expression in vivo. We recently demonstrated that siRNA chemical architectures can be optimized to provide efficient delivery to the CNS, enabling development of CNS-targeted therapeutics. Many genetically-defined neurodegenerative disorders are dominant, favoring selective silencing of the mutant allele. In some cases, successfully targeting the mutant allele requires targeting single nucleotide polymorphism (SNP) heterozygosities. Here, we use Huntington’s disease (HD) as a model. The optimized compound exhibits selective silencing of mutant huntingtin protein in patient-derived cells and throughout the HD mouse brain, demonstrating SNP-based allele-specific RNAi silencing of gene expression in vivo in the CNS. Targeting a disease-causing allele using RNAi-based therapies could be helpful in a range of dominant CNS disorders where maintaining wild-type expression is essential. Chemically modified siRNAs distinguish between mutant and normal huntingtin based on a single nucleotide difference and lower mutant huntingtin specifically in patient derived cells and in a mouse model of Huntington’s disease.
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Affiliation(s)
- Faith Conroy
- Department of Medicine, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Rachael Miller
- Department of Medicine, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Julia F Alterman
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Matthew R Hassler
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Dimas Echeverria
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Bruno M D C Godinho
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Emily G Knox
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Jaquelyn Sousa
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Ken Yamada
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Farah Mahmood
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Adel Boudi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Kimberly Kegel-Gleason
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Neil Aronin
- Department of Medicine, UMass Chan Medical School, Worcester, MA, 01605, USA.,RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Anastasia Khvorova
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, 01605, USA.
| | - Edith L Pfister
- Department of Medicine, UMass Chan Medical School, Worcester, MA, 01605, USA.
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19
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Helm J, Schöls L, Hauser S. Towards Personalized Allele-Specific Antisense Oligonucleotide Therapies for Toxic Gain-of-Function Neurodegenerative Diseases. Pharmaceutics 2022; 14:pharmaceutics14081708. [PMID: 36015334 PMCID: PMC9416334 DOI: 10.3390/pharmaceutics14081708] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/29/2022] Open
Abstract
Antisense oligonucleotides (ASOs) are single-stranded nucleic acid strings that can be used to selectively modify protein synthesis by binding complementary (pre-)mRNA sequences. By specific arrangements of DNA and RNA into a chain of nucleic acids and additional modifications of the backbone, sugar, and base, the specificity and functionality of the designed ASOs can be adjusted. Thereby cellular uptake, toxicity, and nuclease resistance, as well as binding affinity and specificity to its target (pre-)mRNA, can be modified. Several neurodegenerative diseases are caused by autosomal dominant toxic gain-of-function mutations, which lead to toxic protein products driving disease progression. ASOs targeting such mutations—or even more comprehensively, associated variants, such as single nucleotide polymorphisms (SNPs)—promise a selective degradation of the mutant (pre-)mRNA while sparing the wild type allele. By this approach, protein expression from the wild type strand is preserved, and side effects from an unselective knockdown of both alleles can be prevented. This makes allele-specific targeting strategies a focus for future personalized therapies. Here, we provide an overview of current strategies to develop personalized, allele-specific ASO therapies for the treatment of neurodegenerative diseases, such Huntington’s disease (HD) and spinocerebellar ataxia type 3 (SCA3/MJD).
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Affiliation(s)
- Jacob Helm
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Hertie Institute for Clinical Brain Research and Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
- Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Ludger Schöls
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Hertie Institute for Clinical Brain Research and Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
| | - Stefan Hauser
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Hertie Institute for Clinical Brain Research and Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
- Correspondence:
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20
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Tabrizi SJ, Estevez-Fraga C, van Roon-Mom WMC, Flower MD, Scahill RI, Wild EJ, Muñoz-Sanjuan I, Sampaio C, Rosser AE, Leavitt BR. Potential disease-modifying therapies for Huntington's disease: lessons learned and future opportunities. Lancet Neurol 2022; 21:645-658. [PMID: 35716694 PMCID: PMC7613206 DOI: 10.1016/s1474-4422(22)00121-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 02/18/2022] [Accepted: 03/04/2022] [Indexed: 01/03/2023]
Abstract
Huntington's disease is the most frequent autosomal dominant neurodegenerative disorder; however, no disease-modifying interventions are available for patients with this disease. The molecular pathogenesis of Huntington's disease is complex, with toxicity that arises from full-length expanded huntingtin and N-terminal fragments of huntingtin, which are both prone to misfolding due to proteolysis; aberrant intron-1 splicing of the HTT gene; and somatic expansion of the CAG repeat in the HTT gene. Potential interventions for Huntington's disease include therapies targeting huntingtin DNA and RNA, clearance of huntingtin protein, DNA repair pathways, and other treatment strategies targeting inflammation and cell replacement. The early termination of trials of the antisense oligonucleotide tominersen suggest that it is time to reflect on lessons learned, where the field stands now, and the challenges and opportunities for the future.
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Affiliation(s)
- Sarah J Tabrizi
- Huntington's Disease Centre, UCL Queen Square Institute of Neurology, University College London, London, UK.
| | - Carlos Estevez-Fraga
- Huntington's Disease Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | | | - Michael D Flower
- Huntington's Disease Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Rachael I Scahill
- Huntington's Disease Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Edward J Wild
- Huntington's Disease Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | | | - Cristina Sampaio
- CHDI Management, CHDI Foundation Los Angeles, CA, USA; Laboratory of Clinical Pharmacology, Faculdade de Medicina de Lisboa, Lisbon, Portugal
| | - Anne E Rosser
- BRAIN unit, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK
| | - Blair R Leavitt
- Centre for Huntington's disease, University of British Columbia, Vancouver, BC, Canada
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21
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Khang M, Bindra RS, Mark Saltzman W. Intrathecal delivery and its applications in leptomeningeal disease. Adv Drug Deliv Rev 2022; 186:114338. [PMID: 35561835 DOI: 10.1016/j.addr.2022.114338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 04/26/2022] [Accepted: 05/06/2022] [Indexed: 12/22/2022]
Abstract
Intrathecal delivery (IT) of opiates into the cerebrospinal fluid (CSF) for anesthesia and pain relief has been used clinically for decades, but this relatively straightforward approach of bypassing the blood-brain barrier has been underutilized for other indications because of its lack of utility in delivering small lipid-soluble drugs. However, emerging evidence suggests that IT drug delivery be an efficacious strategy for the treatment of cancers in which there is leptomeningeal spread of disease. In this review, we discuss CSF flow dynamics and CSF clearance pathways in the context of intrathecal delivery. We discuss human and animal studies of several new classes of therapeutic agents-cellular, protein, nucleic acid, and nanoparticle-based small molecules-that may benefit from IT delivery. The complexity of the CSF compartment presents several key challenges in predicting biodistribution of IT-delivered drugs. New approaches and strategies are needed that can overcome the high rates of turnover in the CSF to reach specific tissues or cellular targets.
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22
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Shin JW, Shin A, Park SS, Lee JM. Haplotype-specific insertion-deletion variations for allele-specific targeting in Huntington's disease. Mol Ther Methods Clin Dev 2022; 25:84-95. [PMID: 35356757 PMCID: PMC8933729 DOI: 10.1016/j.omtm.2022.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/01/2022] [Indexed: 11/25/2022]
Abstract
Huntington's disease (HD) is a dominantly inherited neurodegenerative disease caused by an expanded CAG repeat in huntingtin (HTT). Given an important role for HTT in development and significant neurodegeneration at the time of clinical manifestation in HD, early treatment of allele-specific drugs represents a promising strategy. The feasibility of an allele-specific antisense oligonucleotide (ASO) targeting single-nucleotide polymorphisms (SNPs) has been demonstrated in models of HD. Here, we constructed a map of haplotype-specific insertion-deletion variations (indels) to develop alternative mutant-HTT-specific strategies. We mapped indels annotated in the 1000 Genomes Project data on common HTT haplotypes, revealing candidate indels for mutant-specific HTT targeting. Subsequent sequencing of an HD family confirmed candidate sites and revealed additional allele-specific indels. Interestingly, the most common normal HTT haplotype carries indels of big allele length differences at many sites, further uncovering promising haplotype-specific targets. When patient-derived cells carrying the most common HTT diplotype were treated with ASOs targeting the mutant alleles of candidate indels (rs772629195 or rs72239206), complete mutant specificity was observed. In summary, our map of haplotype-specific indels permits the identification of allele-specific targets in HD subjects, potentially contributing to the development of safe HTT-lowering therapeutics that are suitable for early treatment in HD.
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Affiliation(s)
- Jun Wan Shin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Aram Shin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Seri S Park
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Jong-Min Lee
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.,Medical and Population Genetics Program, Broad Institute of M.I.T. and Harvard, Cambridge, MA 02142, USA
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23
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Ferguson MW, Kennedy CJ, Palpagama TH, Waldvogel HJ, Faull RLM, Kwakowsky A. Current and Possible Future Therapeutic Options for Huntington’s Disease. J Cent Nerv Syst Dis 2022; 14:11795735221092517. [PMID: 35615642 PMCID: PMC9125092 DOI: 10.1177/11795735221092517] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 03/21/2022] [Indexed: 11/16/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal neurodegenerative disease that is characterized by an excessive number of CAG trinucleotide repeats within the huntingtin gene ( HTT). HD patients can present with a variety of symptoms including chorea, behavioural and psychiatric abnormalities and cognitive decline. Each patient has a unique combination of symptoms, and although these can be managed using a range of medications and non-drug treatments there is currently no cure for the disease. Current therapies prescribed for HD can be categorized by the symptom they treat. These categories include chorea medication, antipsychotic medication, antidepressants, mood stabilizing medication as well as non-drug therapies. Fortunately, there are also many new HD therapeutics currently undergoing clinical trials that target the disease at its origin; lowering the levels of mutant huntingtin protein (mHTT). Currently, much attention is being directed to antisense oligonucleotide (ASO) therapies, which bind to pre-RNA or mRNA and can alter protein expression via RNA degradation, blocking translation or splice modulation. Other potential therapies in clinical development include RNA interference (RNAi) therapies, RNA targeting small molecule therapies, stem cell therapies, antibody therapies, non-RNA targeting small molecule therapies and neuroinflammation targeted therapies. Potential therapies in pre-clinical development include Zinc-Finger Protein (ZFP) therapies, transcription activator-like effector nuclease (TALEN) therapies and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system (Cas) therapies. This comprehensive review aims to discuss the efficacy of current HD treatments and explore the clinical trial progress of emerging potential HD therapeutics.
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Affiliation(s)
- Mackenzie W. Ferguson
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Connor J. Kennedy
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Thulani H. Palpagama
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Henry J. Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Richard L. M. Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre, National University of Ireland Galway, Galway, Ireland
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24
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Gu X, Richman J, Langfelder P, Wang N, Zhang S, Bañez-Coronel M, Wang HB, Yang L, Ramanathan L, Deng L, Park CS, Choi CR, Cantle JP, Gao F, Gray M, Coppola G, Bates GP, Ranum LPW, Horvath S, Colwell CS, Yang XW. Uninterrupted CAG repeat drives striatum-selective transcriptionopathy and nuclear pathogenesis in human Huntingtin BAC mice. Neuron 2022; 110:1173-1192.e7. [PMID: 35114102 PMCID: PMC9462388 DOI: 10.1016/j.neuron.2022.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/30/2021] [Accepted: 01/06/2022] [Indexed: 02/08/2023]
Abstract
In Huntington's disease (HD), the uninterrupted CAG repeat length, but not the polyglutamine length, predicts disease onset. However, the underlying pathobiology remains unclear. Here, we developed bacterial artificial chromosome (BAC) transgenic mice expressing human mutant huntingtin (mHTT) with uninterrupted, and somatically unstable, CAG repeats that exhibit progressive disease-related phenotypes. Unlike prior mHTT transgenic models with stable, CAA-interrupted, polyglutamine-encoding repeats, BAC-CAG mice show robust striatum-selective nuclear inclusions and transcriptional dysregulation resembling those in murine huntingtin knockin models and HD patients. Importantly, the striatal transcriptionopathy in HD models is significantly correlated with their uninterrupted CAG repeat length but not polyglutamine length. Finally, among the pathogenic entities originating from mHTT genomic transgenes and only present or enriched in the uninterrupted CAG repeat model, somatic CAG repeat instability and nuclear mHTT aggregation are best correlated with early-onset striatum-selective molecular pathogenesis and locomotor and sleep deficits, while repeat RNA-associated pathologies and repeat-associated non-AUG (RAN) translation may play less selective or late pathogenic roles, respectively.
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Affiliation(s)
- Xiaofeng Gu
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jeffrey Richman
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peter Langfelder
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Nan Wang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Shasha Zhang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Monica Bañez-Coronel
- Center for Neurogenetics, Department of Molecular Genetics and Microbiology, College of Medicine, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute of Neurological Diseases, University of Florida, Gainesville, FL, USA
| | - Huei-Bin Wang
- Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Lucia Yang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Lalini Ramanathan
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Linna Deng
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Chang Sin Park
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Christopher R Choi
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jeffrey P Cantle
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Fuying Gao
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Michelle Gray
- Department of Neurology and Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Giovanni Coppola
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Gillian P Bates
- Huntington's Disease Centre, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Laura P W Ranum
- Center for Neurogenetics, Department of Molecular Genetics and Microbiology, College of Medicine, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute of Neurological Diseases, University of Florida, Gainesville, FL, USA
| | - Steve Horvath
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Christopher S Colwell
- Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - X William Yang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA; Department Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
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25
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Rook ME, Southwell AL. Antisense Oligonucleotide Therapy: From Design to the Huntington Disease Clinic. BioDrugs 2022; 36:105-119. [PMID: 35254632 PMCID: PMC8899000 DOI: 10.1007/s40259-022-00519-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2022] [Indexed: 12/14/2022]
Abstract
Huntington disease (HD) is a fatal progressive neurodegenerative disorder caused by an inherited mutation in the huntingtin (HTT) gene, which encodes mutant HTT protein. Though HD remains incurable, various preclinical studies have reported a favorable response to HTT suppression, emphasizing HTT lowering strategies as prospective disease-modifying treatments. Antisense oligonucleotides (ASOs) lower HTT by targeting transcripts and are well suited for treating neurodegenerative disorders as they distribute broadly throughout the central nervous system (CNS) and are freely taken up by neurons, glia, and ependymal cells. With the FDA approval of an ASO therapy for another disease of the CNS, spinal muscular atrophy, ASOs have become a particularly attractive therapeutic option for HD. However, two types of ASOs were recently assessed in human clinical trials for the treatment of HD, and both were halted early. In this review, we will explore the differences in chemistry, targeting, and specificity of these HTT ASOs as well as preliminary clinical findings and potential reasons for and implications of these halted trials.
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Affiliation(s)
- Morgan E Rook
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32827, USA.
| | - Amber L Southwell
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32827, USA
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26
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Keller CG, Shin Y, Monteys AM, Renaud N, Beibel M, Teider N, Peters T, Faller T, St-Cyr S, Knehr J, Roma G, Reyes A, Hild M, Lukashev D, Theil D, Dales N, Cha JH, Borowsky B, Dolmetsch R, Davidson BL, Sivasankaran R. An orally available, brain penetrant, small molecule lowers huntingtin levels by enhancing pseudoexon inclusion. Nat Commun 2022; 13:1150. [PMID: 35241644 PMCID: PMC8894458 DOI: 10.1038/s41467-022-28653-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/27/2022] [Indexed: 02/07/2023] Open
Abstract
Huntington's Disease (HD) is a progressive neurodegenerative disorder caused by CAG trinucleotide repeat expansions in exon 1 of the huntingtin (HTT) gene. The mutant HTT (mHTT) protein causes neuronal dysfunction, causing progressive motor, cognitive and behavioral abnormalities. Current treatments for HD only alleviate symptoms, but cerebral spinal fluid (CSF) or central nervous system (CNS) delivery of antisense oligonucleotides (ASOs) or virus vectors expressing RNA-induced silencing (RNAi) moieties designed to induce mHTT mRNA lowering have progressed to clinical trials. Here, we present an alternative disease modifying therapy the orally available, brain penetrant small molecule branaplam. By promoting inclusion of a pseudoexon in the primary transcript, branaplam lowers mHTT protein levels in HD patient cells, in an HD mouse model and in blood samples from Spinal Muscular Atrophy (SMA) Type I patients dosed orally for SMA (NCT02268552). Our work paves the way for evaluating branaplam's utility as an HD therapy, leveraging small molecule splicing modulators to reduce expression of dominant disease genes by driving pseudoexon inclusion.
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Affiliation(s)
| | - Youngah Shin
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Alex Mas Monteys
- The Raymond G Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, USA
| | - Nicole Renaud
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Martin Beibel
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Natalia Teider
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Thomas Peters
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Thomas Faller
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Sophie St-Cyr
- The Raymond G Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Judith Knehr
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Guglielmo Roma
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Alejandro Reyes
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Marc Hild
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | | | - Diethilde Theil
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Natalie Dales
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Jang-Ho Cha
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | | | | | - Beverly L Davidson
- The Raymond G Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, USA.
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27
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Cerebrospinal fluid mutant huntingtin is a biomarker for huntingtin lowering in the striatum of Huntington disease mice. Neurobiol Dis 2022; 166:105652. [PMID: 35143966 PMCID: PMC8901112 DOI: 10.1016/j.nbd.2022.105652] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 12/20/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disease caused by a trinucleotide repeat expansion in the HTT gene encoding an elongated polyglutamine tract in the huntingtin (HTT) protein. Expanded mutant HTT (mHTT) is toxic and leads to regional atrophy and neuronal cell loss in the brain, which occurs earliest in the striatum. Therapeutic lowering of mHTT in the central nervous system (CNS) has shown promise in preclinical studies, with multiple approaches currently in clinical development for HD. Quantitation of mHTT in the cerebrospinal fluid (CSF) is being used as a clinical pharmacodynamic biomarker of target engagement in the CNS. We have previously shown that the CNS is a major source of mHTT in the CSF. However, little is known about the specific brain regions and cell types that contribute to CSF mHTT. Therefore, a better understanding of the origins of CSF mHTT and whether therapies targeting mHTT in the striatum would be expected to be associated with significant lowering of mHTT in the CSF is needed. Here, we use complementary pharmacological and genetic-based approaches to either restrict expression of mHTT to the striatum or selectively deplete mHTT in the striatum to evaluate the contribution of this brain region to mHTT in the CSF. We show that viral expression of a mHTT fragment restricted to the striatum leads to detectable mHTT in the CSF. We demonstrate that targeted lowering of mHTT selectively in the striatum using an antisense oligonucleotide leads to a significant reduction of mHTT in the CSF of HD mice. Furthermore, using a transgenic mouse model of HD that expresses full length human mHTT and wild type HTT, we show that genetic inactivation of mHTT selectively in the striatum results in a significant reduction of mHTT in the CSF. Taken together, our data supports the conclusion that the striatum contributes sufficiently to the pool of mHTT in the CSF that therapeutic levels of mHTT lowering in the striatum can be detected by this measure in HD mice. This suggests that CSF mHTT may represent a pharmacodynamic biomarker for therapies that lower mHTT in the striatum.
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28
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Maruyama R, Nguyen Q, Roshmi RR, Touznik A, Yokota T. Allele-Selective Locked Nucleic Acid Gapmers for the Treatment of Fibrodysplasia Ossificans Progressiva Knock Down the Pathogenic ACVR1 R206H Transcript and Inhibit Osteogenic Differentiation. Nucleic Acid Ther 2022; 32:185-193. [PMID: 35085461 DOI: 10.1089/nat.2021.0009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder characterized by episodic heterotopic ossification. The median life span of people with this disorder is ∼40 years, and currently, there is no effective treatment available. More than 95% of cases are caused by a recurrent mutation (c.617G>A; R206H) of Activin A receptor, type I (ACVR1)/Activin receptor-like kinase-2 (ALK2), a bone morphogenetic protein type I receptor. The mutation renders ACVR1 responsive to activin A, which does not activate wild-type ACVR1. Ectopic activation of ACVR1R206H by activin A induces heterotopic ossification. Since ACVR1R206H is a hyperactive receptor, a promising therapeutic strategy is to decrease the activity of mutated ACVR1. To accomplish this goal, we developed locked nucleic acid (LNA) gapmers. These are short DNA oligonucleotides with LNA modification at both ends. They induce targeted mRNA degradation and specific knockdown of gene expression. We demonstrated that some of these gapmers efficiently knocked down ACVR1R206H expression at RNA levels, while ACVR1WT was mostly unaffected in human FOP fibroblasts. Also, the gapmers suppressed osteogenic differentiation induced by ACVR1R206H and activin A. These gapmers may be promising drug candidates for FOP. This novel strategy will also pave the way for antisense-mediated therapy of other autosomal dominant disorders.
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Affiliation(s)
- Rika Maruyama
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Quynh Nguyen
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Rohini Roy Roshmi
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Aleksander Touznik
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.,The Friends of Garrett Cumming Research & Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, Edmonton, Canada
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29
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Restoring SMN Expression: An Overview of the Therapeutic Developments for the Treatment of Spinal Muscular Atrophy. Cells 2022; 11:cells11030417. [PMID: 35159227 PMCID: PMC8834523 DOI: 10.3390/cells11030417] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder and one of the most common genetic causes of infant death. It is characterized by progressive weakness of the muscles, loss of ambulation, and death from respiratory complications. SMA is caused by the homozygous deletion or mutations in the survival of the motor neuron 1 (SMN1) gene. Humans, however, have a nearly identical copy of SMN1 known as the SMN2 gene. The severity of the disease correlates inversely with the number of SMN2 copies present. SMN2 cannot completely compensate for the loss of SMN1 in SMA patients because it can produce only a fraction of functional SMN protein. SMN protein is ubiquitously expressed in the body and has a variety of roles ranging from assembling the spliceosomal machinery, autophagy, RNA metabolism, signal transduction, cellular homeostasis, DNA repair, and recombination. Motor neurons in the anterior horn of the spinal cord are extremely susceptible to the loss of SMN protein, with the reason still being unclear. Due to the ability of the SMN2 gene to produce small amounts of functional SMN, two FDA-approved treatment strategies, including an antisense oligonucleotide (AON) nusinersen and small-molecule risdiplam, target SMN2 to produce more functional SMN. On the other hand, Onasemnogene abeparvovec (brand name Zolgensma) is an FDA-approved adeno-associated vector 9-mediated gene replacement therapy that can deliver a copy of the human SMN1. In this review, we summarize the SMA etiology, the role of SMN, and discuss the challenges of the therapies that are approved for SMA treatment.
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Maity S, Komal P, Kumar V, Saxena A, Tungekar A, Chandrasekar V. Impact of ER Stress and ER-Mitochondrial Crosstalk in Huntington's Disease. Int J Mol Sci 2022; 23:780. [PMID: 35054963 PMCID: PMC8775980 DOI: 10.3390/ijms23020780] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 02/07/2023] Open
Abstract
Accumulation of misfolded proteins is a common phenomenon of several neurodegenerative diseases. The misfolding of proteins due to abnormal polyglutamine (PolyQ) expansions are linked to the development of PolyQ diseases including Huntington's disease (HD). Though the genetic basis of PolyQ repeats in HD remains prominent, the primary molecular basis mediated by PolyQ toxicity remains elusive. Accumulation of misfolded proteins in the ER or disruption of ER homeostasis causes ER stress and activates an evolutionarily conserved pathway called Unfolded protein response (UPR). Protein homeostasis disruption at organelle level involving UPR or ER stress response pathways are found to be linked to HD. Due to dynamic intricate connections between ER and mitochondria, proteins at ER-mitochondria contact sites (mitochondria associated ER membranes or MAMs) play a significant role in HD development. The current review aims at highlighting the most updated information about different UPR pathways and their involvement in HD disease progression. Moreover, the role of MAMs in HD progression has also been discussed. In the end, the review has focused on the therapeutic interventions responsible for ameliorating diseased states via modulating either ER stress response proteins or modulating the expression of ER-mitochondrial contact proteins.
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Affiliation(s)
- Shuvadeep Maity
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS)-Pilani (Hyderabad Campus), Shameerpet-Mandal, Hyderabad 500078, Telangana, India; (P.K.); (V.K.); (A.S.); (A.T.); (V.C.)
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Small molecule splicing modifiers with systemic HTT-lowering activity. Nat Commun 2021; 12:7299. [PMID: 34911927 PMCID: PMC8674292 DOI: 10.1038/s41467-021-27157-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 10/28/2021] [Indexed: 02/07/2023] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the huntingtin (HTT) gene. Consequently, the mutant protein is ubiquitously expressed and drives pathogenesis of HD through a toxic gain-of-function mechanism. Animal models of HD have demonstrated that reducing huntingtin (HTT) protein levels alleviates motor and neuropathological abnormalities. Investigational drugs aim to reduce HTT levels by repressing HTT transcription, stability or translation. These drugs require invasive procedures to reach the central nervous system (CNS) and do not achieve broad CNS distribution. Here, we describe the identification of orally bioavailable small molecules with broad distribution throughout the CNS, which lower HTT expression consistently throughout the CNS and periphery through selective modulation of pre-messenger RNA splicing. These compounds act by promoting the inclusion of a pseudoexon containing a premature termination codon (stop-codon psiExon), leading to HTT mRNA degradation and reduction of HTT levels.
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Komatsu H. Innovative Therapeutic Approaches for Huntington's Disease: From Nucleic Acids to GPCR-Targeting Small Molecules. Front Cell Neurosci 2021; 15:785703. [PMID: 34899193 PMCID: PMC8662694 DOI: 10.3389/fncel.2021.785703] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/08/2021] [Indexed: 12/02/2022] Open
Abstract
Huntington’s disease (HD) is a fatal neurodegenerative disorder due to an extraordinarily expanded CAG repeat in the huntingtin gene that confers a gain-of-toxic function in the mutant protein. There is currently no effective cure that attenuates progression and severity of the disease. Since HD is an inherited monogenic disorder, lowering the mutant huntingtin (mHTT) represents a promising therapeutic strategy. Huntingtin lowering strategies mostly focus on nucleic acid approaches, such as small interfering RNAs (siRNAs) and antisense oligonucleotides (ASOs). While these approaches seem to be effective, the drug delivery to the brain poses a great challenge and requires direct injection into the central nervous system (CNS) that results in substantial burden for patients. This review discusses the topics on Huntingtin lowering strategies with clinical trials in patients already underway and introduce an innovative approach that has the potential to deter the disease progression through the inhibition of GPR52, a striatal-enriched class A orphan G protein-coupled receptor (GPCR) that represents a promising therapeutic target for psychiatric disorders. Chemically simple, potent, and selective GPR52 antagonists have been discovered through high-throughput screening and subsequent structure-activity relationship studies. These small molecule antagonists not only diminish both soluble and aggregated mHTT in the striatum, but also ameliorate HD-like defects in HD mice. This therapeutic approach offers great promise as a novel strategy for HD therapy, while nucleic acid delivery still faces considerable challenges.
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Affiliation(s)
- Hidetoshi Komatsu
- Business Strategy, Kyowa Pharmaceutical Industry Co., Ltd., Osaka, Japan.,Department of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
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Jarosińska OD, Rüdiger SGD. Molecular Strategies to Target Protein Aggregation in Huntington's Disease. Front Mol Biosci 2021; 8:769184. [PMID: 34869596 PMCID: PMC8636123 DOI: 10.3389/fmolb.2021.769184] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/18/2021] [Indexed: 11/30/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the aggregation of the mutant huntingtin (mHTT) protein in nerve cells. mHTT self-aggregates to form soluble oligomers and insoluble fibrils, which interfere in a number of key cellular functions. This leads to cell quiescence and ultimately cell death. There are currently still no treatments available for HD, but approaches targeting the HTT levels offer systematic, mechanism-driven routes towards curing HD and other neurodegenerative diseases. This review summarizes the current state of knowledge of the mRNA targeting approaches such as antisense oligonucleotides and RNAi system; and the novel methods targeting mHTT and aggregates for degradation via the ubiquitin proteasome or the autophagy-lysosomal systems. These methods include the proteolysis-targeting chimera, Trim-Away, autophagosome-tethering compound, autophagy-targeting chimera, lysosome-targeting chimera and approach targeting mHTT for chaperone-mediated autophagy. These molecular strategies provide a knowledge-based approach to target HD and other neurodegenerative diseases at the origin.
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Affiliation(s)
- Olga D. Jarosińska
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, Netherlands
- Science for Life, Utrecht University, Utrecht, Netherlands
| | - Stefan G. D. Rüdiger
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, Netherlands
- Science for Life, Utrecht University, Utrecht, Netherlands
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Lemarié FL, Caron NS, Sanders SS, Schmidt ME, Nguyen YTN, Ko S, Xu X, Pouladi MA, Martin DDO, Hayden MR. Rescue of aberrant huntingtin palmitoylation ameliorates mutant huntingtin-induced toxicity. Neurobiol Dis 2021; 158:105479. [PMID: 34390831 DOI: 10.1016/j.nbd.2021.105479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/29/2021] [Accepted: 08/09/2021] [Indexed: 01/14/2023] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by a CAG expansion in the HTT gene that codes for an elongated polyglutamine tract in the huntingtin (HTT) protein. HTT is subject to multiple post-translational modifications (PTMs) that regulate its cellular function. Mutating specific PTM sites within mutant HTT (mHTT) in HD mouse models can modulate disease phenotypes, highlighting the key role of HTT PTMs in the pathogenesis of HD. These findings have led to increased interest in developing small molecules to modulate HTT PTMs in order to decrease mHTT toxicity. However, the therapeutic efficacy of pharmacological modulation of HTT PTMs in preclinical HD models remains largely unknown. HTT is palmitoylated at cysteine 214 by the huntingtin-interacting protein 14 (HIP14 or ZDHHC17) and 14-like (HIP14L or ZDHHC13) acyltransferases. Here, we assessed if HTT palmitoylation should be regarded as a therapeutic target to treat HD by (1) investigating palmitoylation dysregulation in rodent and human HD model systems, (2) measuring the impact of mHTT-lowering therapy on brain palmitoylation, and (3) evaluating if HTT palmitoylation can be pharmacologically modulated. We show that palmitoylation of mHTT and some HIP14/HIP14L-substrates is decreased early in multiple HD mouse models, and that mHTT palmitoylation decreases further with aging. Lowering mHTT in the brain of YAC128 mice is not sufficient to rescue aberrant palmitoylation. However, we demonstrate that mHTT palmitoylation can be normalized in COS-7 cells, in YAC128 cortico-striatal primary neurons and HD patient-derived lymphoblasts using an acyl-protein thioesterase (APT) inhibitor. Moreover, we show that modulating palmitoylation reduces mHTT aggregation and mHTT-induced cytotoxicity in COS-7 cells and YAC128 neurons.
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Affiliation(s)
- Fanny L Lemarié
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Shaun S Sanders
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada; Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Mandi E Schmidt
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Yen T N Nguyen
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Seunghyun Ko
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Xiaohong Xu
- Department of Neurology and Stroke Center, The First Affiliated Hospital, Jinan University, Guangzhou, China; Translational Laboratory in Genetic Medicine, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mahmoud A Pouladi
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada; Translational Laboratory in Genetic Medicine, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada; Department of Biology, University of Waterloo, Waterloo, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada.
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Yildirim F, Foddis M, Blumenau S, Müller S, Kajetan B, Holtgrewe M, Kola V, Beule D, Sassi C. Shared and oppositely regulated transcriptomic signatures in Huntington's disease and brain ischemia confirm known and unveil novel potential neuroprotective genes. Neurobiol Aging 2021; 104:122.e1-122.e17. [PMID: 33875290 DOI: 10.1016/j.neurobiolaging.2021.03.001] [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: 02/23/2020] [Revised: 02/13/2021] [Accepted: 03/02/2021] [Indexed: 11/20/2022]
Abstract
Huntington's disease and subcortical vascular dementia display similar dementing features, shaped by different degrees of striatal atrophy, deep white matter degeneration and tau pathology. To investigate the hypothesis that Huntington's disease transcriptomic hallmarks may provide a window into potential protective genes upregulated during brain acute and subacute ischemia, we compared RNA sequencing signatures in the most affected brain areas of 2 widely used experimental mouse models: Huntington's disease, (R6/2, striatum and cortex and Q175, hippocampus) and brain ischemia-subcortical vascular dementia (BCCAS, striatum, cortex and hippocampus). We identified a cluster of 55 shared genes significantly differentially regulated in both models and we screened these in 2 different mouse models of Alzheimer's disease, and 96 early-onset familial and apparently sporadic small vessel ischemic disease patients. Our data support the prevalent role of transcriptional regulation upon genetic coding variability of known neuroprotective genes (Egr2, Fos, Ptgs2, Itga5, Cdkn1a, Gsn, Npas4, Btg2, Cebpb) and provide a list of potential additional ones likely implicated in different dementing disorders and worth further investigation.
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Affiliation(s)
- Ferah Yildirim
- Department of Neuropsychiatry, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Marco Foddis
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Sonja Blumenau
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Susanne Müller
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Bentele Kajetan
- Berlin Institute of Health, BIH, Core Unit Bioinformatics, Berlin, Germany
| | - Manuel Holtgrewe
- Berlin Institute of Health, BIH, Core Unit Bioinformatics, Berlin, Germany
| | - Vasilis Kola
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Dieter Beule
- Berlin Institute of Health, BIH, Core Unit Bioinformatics, Berlin, Germany
| | - Celeste Sassi
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
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36
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Bizot F, Vulin A, Goyenvalle A. Current Status of Antisense Oligonucleotide-Based Therapy in Neuromuscular Disorders. Drugs 2021; 80:1397-1415. [PMID: 32696107 DOI: 10.1007/s40265-020-01363-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neuromuscular disorders include a wide range of diseases affecting the peripheral nervous system, which are primarily characterized by progressive muscle weakness and wasting. While there were no effective therapies until recently, several therapeutic approaches have advanced to clinical trials in the past few years. Among these, the antisense technology aiming at modifying RNA processing and function has remarkably progressed and a few antisense oligonucleotides (ASOs) have now been approved. Despite these recent clinical successes, several ASOs have also failed and clinical programs have been suspended, in most cases when the route of administration was systemic, highlighting the existing challenges notably with respect to effective ASO delivery. In this review we summarize the recent advances and current status of antisense based-therapies for neuromuscular disorders, using successful as well as unsuccessful examples to highlight the variability of outcomes depending on the target tissue and route of administration. We describe the different ASO-mediated therapeutic approaches, including splice-switching applications, steric-blocking strategies and targeted gene knock-down mediated by ribonuclease H recruitment. In this overview, we discuss the merits and challenges of the current ASO technology, and discuss the future of ASO development.
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Affiliation(s)
- Flavien Bizot
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000, Versailles, France
| | - Adeline Vulin
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000, Versailles, France.,SQY Therapeutics, Université de Versailles St-Quentin, Montigny le Bretonneux, France
| | - Aurélie Goyenvalle
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, 78000, Versailles, France. .,LIA BAHN, Centre scientifique de Monaco, Monaco, Monaco.
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37
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Borbolla-Jiménez FV, Del Prado-Audelo ML, Cisneros B, Caballero-Florán IH, Leyva-Gómez G, Magaña JJ. New Perspectives of Gene Therapy on Polyglutamine Spinocerebellar Ataxias: From Molecular Targets to Novel Nanovectors. Pharmaceutics 2021; 13:1018. [PMID: 34371710 PMCID: PMC8309146 DOI: 10.3390/pharmaceutics13071018] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 01/03/2023] Open
Abstract
Seven of the most frequent spinocerebellar ataxias (SCAs) are caused by a pathological expansion of a cytosine, adenine and guanine (CAG) trinucleotide repeat located in exonic regions of unrelated genes, which in turn leads to the synthesis of polyglutamine (polyQ) proteins. PolyQ proteins are prone to aggregate and form intracellular inclusions, which alter diverse cellular pathways, including transcriptional regulation, protein clearance, calcium homeostasis and apoptosis, ultimately leading to neurodegeneration. At present, treatment for SCAs is limited to symptomatic intervention, and there is no therapeutic approach to prevent or reverse disease progression. This review provides a compilation of the experimental advances obtained in cell-based and animal models toward the development of gene therapy strategies against polyQ SCAs, providing a discussion of their potential application in clinical trials. In the second part, we describe the promising potential of nanotechnology developments to treat polyQ SCA diseases. We describe, in detail, how the design of nanoparticle (NP) systems with different physicochemical and functionalization characteristics has been approached, in order to determine their ability to evade the immune system response and to enhance brain delivery of molecular tools. In the final part of this review, the imminent application of NP-based strategies in clinical trials for the treatment of polyQ SCA diseases is discussed.
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Affiliation(s)
- Fabiola V. Borbolla-Jiménez
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Ciudad de México 14389, Mexico;
- Programa de Ciencias Biomédicas, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - María Luisa Del Prado-Audelo
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey Campus Ciudad de México, Ciudad de México 14380, Mexico;
| | - Bulmaro Cisneros
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México 07360, Mexico;
| | - Isaac H. Caballero-Florán
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
- Departamento de Farmacia, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México 07360, Mexico
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
| | - Jonathan J. Magaña
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Ciudad de México 14389, Mexico;
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey Campus Ciudad de México, Ciudad de México 14380, Mexico;
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38
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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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Caron NS, Anderson C, Black HF, Sanders SS, Lemarié FL, Doty CN, Hayden MR. Reliable Resolution of Full-Length Huntingtin Alleles by Quantitative Immunoblotting. J Huntingtons Dis 2021; 10:355-365. [PMID: 34092649 DOI: 10.3233/jhd-200463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Therapeutics that lower mutant huntingtin (mHTT) have shown promise in preclinical studies and are in clinical development for the treatment of Huntington's disease (HD). Multiple assays have been developed that either quantify mHTT or total HTT but may not accurately measure levels of wild type HTT (wtHTT) in biological samples. OBJECTIVE To optimize a method that can be used to resolve, quantify and directly compare levels of full length wtHTT and mHTT in HD samples. METHODS We provide a detailed quantitative immunoblotting protocol to reproducibly resolve full length wtHTT and mHTT in multiple HD mouse and patient samples. RESULTS We show that this assay can be modified, depending on the sample, to resolve wtHTT and mHTT with a wide range of polyglutamine differences (ΔQs 22-179). We also demonstrate that this method can be used to quantify allele-selective lowering of mHTT using an antisense oligonucleotide in HD patient-derived cells. CONCLUSION This quantitative immunoblotting method can be used to reliably resolve full length HTT alleles with ΔQs≥22 and allows for direct comparison of wtHTT and mHTT levels in HD samples.
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Affiliation(s)
- Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | | | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Shaun S Sanders
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,Current address: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Fanny L Lemarié
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
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40
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Brooker SM, Edamakanti CR, Akasha SM, Kuo SH, Opal P. Spinocerebellar ataxia clinical trials: opportunities and challenges. Ann Clin Transl Neurol 2021; 8:1543-1556. [PMID: 34019331 PMCID: PMC8283160 DOI: 10.1002/acn3.51370] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/14/2022] Open
Abstract
The spinocerebellar ataxias (SCAs) are a group of dominantly inherited diseases that share the defining feature of progressive cerebellar ataxia. The disease process, however, is not confined to the cerebellum; other areas of the brain, in particular, the brainstem, are also affected, resulting in a high burden of morbidity and mortality. Currently, there are no disease‐modifying treatments for the SCAs, but preclinical research has led to the development of therapeutic agents ripe for testing in patients. Unfortunately, due to the rarity of these diseases and their slow and variable progression, there are substantial hurdles to overcome in conducting clinical trials. While the epidemiological features of the SCAs are immutable, the feasibility of conducting clinical trials is being addressed through a combination of strategies. These include improvements in clinical outcome measures, the identification of imaging and fluid biomarkers, and innovations in clinical trial design. In this review, we highlight current challenges in initiating clinical trials for the SCAs and also discuss pathways for researchers and clinicians to mitigate these challenges and harness opportunities for clinical trial development.
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Affiliation(s)
- Sarah M Brooker
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Sara M Akasha
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Sheng-Han Kuo
- Department of Neurology, Columbia University, New York, New York, USA.,Initiative for Columbia Ataxia and Tremor, Columbia University, New York, New York, USA
| | - Puneet Opal
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Aslesh T, Yokota T. Development of Antisense Oligonucleotide Gapmers for the Treatment of Huntington's Disease. Methods Mol Biol 2021; 2176:57-67. [PMID: 32865782 DOI: 10.1007/978-1-0716-0771-8_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The field of neuromuscular and neurodegenerative diseases has been revolutionized by the advent of genetics and molecular biology to evaluate the pathogenicity, thereby providing considerable insight to develop suitable therapies. With the successful translation of antisense oligonucleotides (AOs) from in vitro into animal models and clinical practice, modifications are being continuously made to the AOs to improve the pharmacokinetics and pharmacodynamics. In order to activate RNase H-mediated cleavage of the target mRNA, as well as to increase the binding affinity and specificity, gapmer AOs are designed to have a phosphorothioate (PS) backbone flanked with the modified AOs on both sides. Antisense-mediated knockdown of mutated huntingtin is a promising therapeutic approach for Huntington's disease (HD), a devastating disorder affecting the motor and cognitive abilities. This chapter focuses on the modified gapmer AOs for the treatment of HD.
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Affiliation(s)
- Tejal Aslesh
- Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada. .,The Friends of Garrett Cumming Research and Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, Edmonton, AB, Canada.
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de Vrieze E, Cañas Martín J, Peijnenborg J, Martens A, Oostrik J, van den Heuvel S, Neveling K, Pennings R, Kremer H, van Wijk E. AON-based degradation of c.151C>T mutant COCH transcripts associated with dominantly inherited hearing impairment DFNA9. MOLECULAR THERAPY-NUCLEIC ACIDS 2021; 24:274-283. [PMID: 33815940 PMCID: PMC7985667 DOI: 10.1016/j.omtn.2021.02.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 02/24/2021] [Indexed: 01/22/2023]
Abstract
The c.151C>T founder mutation in COCH is a frequent cause of late-onset, dominantly inherited hearing impairment and vestibular dysfunction (DFNA9) in the Dutch/Belgian population. The initial clinical symptoms only manifest between the 3rd and 5th decade of life, which leaves ample time for therapeutic intervention. The dominant inheritance pattern and established non-haploinsufficiency disease mechanism indicate that suppressing translation of mutant COCH transcripts has high therapeutic potential. Single-molecule real-time (SMRT) sequencing resulted in the identification of 11 variants with a low population frequency (<10%) that are specific to the c.151C>T mutant COCH allele. Proof of concept was obtained that gapmer antisense oligonucleotides (AONs), directed against the c.151C>T mutation or mutant allele-specific intronic variants, are able to induce mutant COCH transcript degradation when delivered to transgenic cells expressing COCH minigenes. The most potent AON, directed against the c.151C>T mutation, was able to induce a 60% decrease in mutant COCH transcripts without affecting wild-type COCH transcript levels. Allele specificity decreased when increasing concentrations of AON were delivered to the cells. With the proven safety of AONs in humans, and rapid advancements in inner ear drug delivery, our in vitro studies indicate that AONs offer a promising treatment modality for DFNA9.
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Affiliation(s)
- Erik de Vrieze
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Corresponding author: Erik de Vrieze, Department of Otorhinolaryngology, Radboud University Medical Center, P.O. Box 9101, 6525 GA Nijmegen (Route 855), the Netherlands.
| | - Jorge Cañas Martín
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Jolien Peijnenborg
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Aniek Martens
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Jaap Oostrik
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Simone van den Heuvel
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Ronald Pennings
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Hannie Kremer
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
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Shacham T, Patel C, Lederkremer GZ. PERK Pathway and Neurodegenerative Disease: To Inhibit or to Activate? Biomolecules 2021; 11:biom11030354. [PMID: 33652720 PMCID: PMC7996871 DOI: 10.3390/biom11030354] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 12/12/2022] Open
Abstract
With the extension of life span in recent decades, there is an increasing burden of late-onset neurodegenerative diseases, for which effective treatments are lacking. Neurodegenerative diseases include the widespread Alzheimer’s disease (AD) and Parkinson’s disease (PD), the less frequent Huntington’s disease (HD) and Amyotrophic Lateral Sclerosis (ALS) and also rare early-onset diseases linked to mutations that cause protein aggregation or loss of function in genes that maintain protein homeostasis. The difficulties in applying gene therapy approaches to tackle these diseases is drawing increasing attention to strategies that aim to inhibit cellular toxicity and restore homeostasis by intervening in cellular pathways. These include the unfolded protein response (UPR), activated in response to endoplasmic reticulum (ER) stress, a cellular affliction that is shared by these diseases. Special focus is turned to the PKR-like ER kinase (PERK) pathway of the UPR as a target for intervention. However, the complexity of the pathway and its ability to promote cell survival or death, depending on ER stress resolution, has led to some confusion in conflicting studies. Both inhibition and activation of the PERK pathway have been reported to be beneficial in disease models, although there are also some reports where they are counterproductive. Although with the current knowledge a definitive answer cannot be given on whether it is better to activate or to inhibit the pathway, the most encouraging strategies appear to rely on boosting some steps without compromising downstream recovery.
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Affiliation(s)
- Talya Shacham
- Cell Biology Division, George Wise Faculty of Life Sciences, The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 69978, Israel; (T.S.); (C.P.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Chaitanya Patel
- Cell Biology Division, George Wise Faculty of Life Sciences, The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 69978, Israel; (T.S.); (C.P.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gerardo Z. Lederkremer
- Cell Biology Division, George Wise Faculty of Life Sciences, The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 69978, Israel; (T.S.); (C.P.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
- Correspondence: ; Tel.: +972-3-640-9239
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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: 25] [Impact Index Per Article: 8.3] [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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Minakawa EN, Nagai Y. Protein Aggregation Inhibitors as Disease-Modifying Therapies for Polyglutamine Diseases. Front Neurosci 2021; 15:621996. [PMID: 33642983 PMCID: PMC7907447 DOI: 10.3389/fnins.2021.621996] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/18/2021] [Indexed: 12/11/2022] Open
Abstract
The polyglutamine (polyQ) diseases are a group of inherited neurodegenerative diseases caused by the abnormal expansion of a CAG trinucleotide repeat that are translated into an expanded polyQ stretch in the disease-causative proteins. The expanded polyQ stretch itself plays a critical disease-causative role in the pathomechanisms underlying polyQ diseases. Notably, the expanded polyQ stretch undergoes a conformational transition from the native monomer into the β-sheet-rich monomer, followed by the formation of soluble oligomers and then insoluble aggregates with amyloid fibrillar structures. The intermediate soluble species including the β-sheet-rich monomer and oligomers exhibit substantial neurotoxicity. Therefore, protein conformation stabilization and aggregation inhibition that target the upstream of the insoluble aggregate formation would be a promising approach toward the development of disease-modifying therapies for polyQ diseases. PolyQ aggregation inhibitors of different chemical categories, such as intrabodies, peptides, and small chemical compounds, have been identified through intensive screening methods. Among them, recent advances in the brain delivery methods of several peptides and the screening of small chemical compounds have brought them closer to clinical utility. Notably, the recent discovery of arginine as a potent conformation stabilizer and aggregation inhibitor of polyQ proteins both in vitro and in vivo have paved way to the clinical trial for the patients with polyQ diseases. Meanwhile, expression reduction of expanded polyQ proteins per se would be another promising approach toward disease modification of polyQ diseases. Gene silencing, especially by antisense oligonucleotides (ASOs), have succeeded in reducing the expression of polyQ proteins in the animal models of various polyQ diseases by targeting the aberrant mRNA with expanded CAG repeats. Of note, some of these ASOs have recently been translated into clinical trials. Here we overview and discuss these recent advances toward the development of disease modifying therapies for polyQ diseases. We envision that combination therapies using aggregation inhibitors and gene silencing would meet the needs of the patients with polyQ diseases and their caregivers in the near future to delay or prevent the onset and progression of these currently intractable diseases.
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Affiliation(s)
- Eiko N Minakawa
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Yoshitaka Nagai
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan.,Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Japan
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Jafar-nejad P, Powers B, Soriano A, Zhao H, Norris DA, Matson J, DeBrosse-Serra B, Watson J, Narayanan P, Chun S, Mazur C, Kordasiewicz H, Swayze EE, Rigo F. The atlas of RNase H antisense oligonucleotide distribution and activity in the CNS of rodents and non-human primates following central administration. Nucleic Acids Res 2021; 49:657-673. [PMID: 33367834 PMCID: PMC7826274 DOI: 10.1093/nar/gkaa1235] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 11/23/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022] Open
Abstract
Antisense oligonucleotides (ASOs) have emerged as a new class of drugs to treat a wide range of diseases, including neurological indications. Spinraza, an ASO that modulates splicing of SMN2 RNA, has shown profound disease modifying effects in Spinal Muscular Atrophy (SMA) patients, energizing efforts to develop ASOs for other neurological diseases. While SMA specifically affects spinal motor neurons, other neurological diseases affect different central nervous system (CNS) regions, neuronal and non-neuronal cells. Therefore, it is important to characterize ASO distribution and activity in all major CNS structures and cell types to have a better understanding of which neurological diseases are amenable to ASO therapy. Here we present for the first time the atlas of ASO distribution and activity in the CNS of mice, rats, and non-human primates (NHP), species commonly used in preclinical therapeutic development. Following central administration of an ASO to rodents, we observe widespread distribution and target RNA reduction throughout the CNS in neurons, oligodendrocytes, astrocytes and microglia. This is also the case in NHP, despite a larger CNS volume and more complex neuroarchitecture. Our results demonstrate that ASO drugs are well suited for treating a wide range of neurological diseases for which no effective treatments are available.
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Affiliation(s)
| | - Berit Powers
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
| | | | - Hien Zhao
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
| | | | - John Matson
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
| | | | - Jamie Watson
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
| | | | - Seung J Chun
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
| | - Curt Mazur
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
| | | | | | - Frank Rigo
- Ionis Pharmaceuticals Inc. Carlsbad, CA 92010, USA
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Abstract
The genetic basis for most inherited neurodegenerative diseases has been identified, yet there are limited disease-modifying therapies for these patients. A new class of drugs-antisense oligonucleotides (ASOs)-show promise as a therapeutic platform for treating neurological diseases. ASOs are designed to bind to the RNAs either by promoting degradation of the targeted RNA or by elevating expression by RNA splicing. Intrathecal injection into the cerebral spinal fluid results in broad distribution of antisense drugs and long-term effects. Approval of nusinersen in 2016 demonstrated that effective treatments for neurodegenerative diseases can be identified and that treatments not only slow disease progression but also improve some symptoms. Antisense drugs are currently in development for amyotrophic lateral sclerosis, Huntington's disease, Alzheimer's disease, Parkinson's disease, and Angelman syndrome, and several drugs are in late-stage research for additional neurological diseases. This review highlights the advances in antisense technology as potential treatments for neurological diseases.
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Affiliation(s)
- C Frank Bennett
- Ionis Pharmaceuticals Inc., Carlsbad, California 92010, USA;
| | | | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA
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Mutant Huntingtin Is Cleared from the Brain via Active Mechanisms in Huntington Disease. J Neurosci 2020; 41:780-796. [PMID: 33310753 DOI: 10.1523/jneurosci.1865-20.2020] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/17/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disease caused by a CAG trinucleotide repeat expansion in the huntingtin (HTT) gene. Therapeutics that lower HTT have shown preclinical promise and are being evaluated in clinical trials. However, clinical assessment of brain HTT lowering presents challenges. We have reported that mutant HTT (mHTT) in the CSF of HD patients correlates with clinical measures, including disease burden as well as motor and cognitive performance. We have also shown that lowering HTT in the brains of HD mice results in correlative reduction of mHTT in the CSF, prompting the use of this measure as an exploratory marker of target engagement in clinical trials. In this study, we investigate the mechanisms of mHTT clearance from the brain in adult mice of both sexes to elucidate the significance of therapy-induced CSF mHTT changes. We demonstrate that, although neurodegeneration increases CSF mHTT concentrations, mHTT is also present in the CSF of mice in the absence of neurodegeneration. Importantly, we show that secretion of mHTT from cells in the CNS followed by glymphatic clearance from the extracellular space contributes to mHTT in the CSF. Furthermore, we observe secretion of wild type HTT from healthy control neurons, suggesting that HTT secretion is a normal process occurring in the absence of pathogenesis. Overall, our data support both passive release and active clearance of mHTT into CSF, suggesting that its treatment-induced changes may represent a combination of target engagement and preservation of neurons.SIGNIFICANCE STATEMENT: Changes in CSF mutant huntingtin (mHTT) are being used as an exploratory endpoint in HTT lowering clinical trials for the treatment of Huntington disease (HD). Recently, it was demonstrated that intrathecal administration of a HTT lowering agent leads to dose-dependent reduction of CSF mHTT in HD patients. However, little is known about how HTT, an intracellular protein, reaches the extracellular space and ultimately the CSF. Our findings that HTT enters CSF by both passive release and active secretion followed by glymphatic clearance may have significant implications for interpretation of treatment-induced changes of CSF mHTT in clinical trials for HD.
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Antisense Transcription across Nucleotide Repeat Expansions in Neurodegenerative and Neuromuscular Diseases: Progress and Mysteries. Genes (Basel) 2020; 11:genes11121418. [PMID: 33261024 PMCID: PMC7760973 DOI: 10.3390/genes11121418] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Unstable repeat expansions and insertions cause more than 30 neurodegenerative and neuromuscular diseases. Remarkably, bidirectional transcription of repeat expansions has been identified in at least 14 of these diseases. More remarkably, a growing number of studies has been showing that both sense and antisense repeat RNAs are able to dysregulate important cellular pathways, contributing together to the observed clinical phenotype. Notably, antisense repeat RNAs from spinocerebellar ataxia type 7, myotonic dystrophy type 1, Huntington's disease and frontotemporal dementia/amyotrophic lateral sclerosis associated genes have been implicated in transcriptional regulation of sense gene expression, acting either at a transcriptional or posttranscriptional level. The recent evidence that antisense repeat RNAs could modulate gene expression broadens our understanding of the pathogenic pathways and adds more complexity to the development of therapeutic strategies for these disorders. In this review, we cover the amazing progress made in the understanding of the pathogenic mechanisms associated with repeat expansion neurodegenerative and neuromuscular diseases with a focus on the impact of antisense repeat transcription in the development of efficient therapies.
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Wright GEB, Black HF, Collins JA, Gall-Duncan T, Caron NS, Pearson CE, Hayden MR. Interrupting sequence variants and age of onset in Huntington's disease: clinical implications and emerging therapies. Lancet Neurol 2020; 19:930-939. [PMID: 33098802 DOI: 10.1016/s1474-4422(20)30343-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Huntington's disease is a fatal neurodegenerative disorder that is caused by CAG-CAA repeat expansion, encoding polyglutamine, in the huntingtin (HTT) gene. Current age-of-clinical-onset prediction models for Huntington's disease are based on polyglutamine length and explain only a proportion of the variability in age of onset observed between patients. These length-based assays do not interrogate the underlying genetic variation, because known genetic variants in this region do not alter the protein coding sequence. Given that individuals with identical repeat lengths can present with Huntington's disease decades apart, the search for genetic modifiers of clinical age of onset has become an active area of research. RECENT DEVELOPMENTS Results from three independent genetic studies of Huntington's disease have shown that glutamine-encoding CAA variants that interrupt DNA CAG repeat tracts, but do not alter polyglutamine length or polyglutamine homogeneity, are associated with substantial differences in age of onset of Huntington's disease in carriers. A variant that results in the loss of CAA interruption is associated with early onset and is particularly relevant to individuals that carry alleles in the reduced penetrance range (ie, CAG 36-39). Approximately a third of clinically manifesting carriers of reduced penetrance alleles, defined by current diagnostics, carry this variant. Somatic repeat instability, modified by interrupted CAG tracts, is the most probable cause mediating this effect. This relationship is supported by genome-wide screens for disease modifiers, which have revealed the importance of DNA-repair genes in Huntington's disease (ie, FAN1, LIG1, MLH1, MSH3, PMS1, and PMS2). WHERE NEXT?: Focus needs to be placed on refining our understanding of the effect of the loss-of-interruption and duplication-of-interruption variants and other interrupting sequence variants on age of onset, and assessing their effect in disease-relevant brain tissues, as well as in diverse population groups, such as individuals from Africa and Asia. Diagnostic tests should be augmented or updated, since current tests do not assess the underlying DNA sequence variation, especially when assessing individuals that carry alleles in the reduced penetrance range. Future studies should explore somatic repeat instability and DNA repair as new therapeutic targets to modify age of onset in Huntington's disease and in other repeat-mediated disorders. Disease-modifying therapies could potentially be developed by therapeutically targeting these processes. Promising approaches include therapeutically targeting the expanded repeat or directly perturbing key DNA-repair genes (eg, with antisense oligonucleotides or small molecules). Targeting the CAG repeat directly with naphthyridine-azaquinolone, a compound that induces contractions, and altering the expression of MSH3, represent two viable therapeutic strategies. However, as a first step, the capability of such novel therapeutic approaches to delay clinical onset in animal models should be assessed.
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Affiliation(s)
- Galen E B Wright
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada; Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Jennifer A Collins
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Terence Gall-Duncan
- Program of Genetics and Genome Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Christopher E Pearson
- Program of Genetics and Genome Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada.
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