1
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Krzystek TJ, Rathnayake R, Zeng J, Huang J, Iacobucci G, Yu MC, Gunawardena S. Opposing roles for GSK3β and ERK1-dependent phosphorylation of huntingtin during neuronal dysfunction and cell death in Huntington's disease. Cell Death Dis 2025; 16:328. [PMID: 40263294 PMCID: PMC12015319 DOI: 10.1038/s41419-025-07524-0] [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: 07/03/2024] [Revised: 02/11/2025] [Accepted: 03/12/2025] [Indexed: 04/24/2025]
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder that manifests from an N-terminal polyQ-expansion (>35) in the Huntingtin (HTT) gene leading to axonal degeneration and significant neuronal death. Despite evidence for a scaffolding role for HTT in membrane-related processes such as endocytosis, vesicle transport, and vesicle fusion, it remains unclear how polyQ-expansion alters membrane binding during these processes. Using quantitative Mass Spectrometry-based proteomics on HTT-containing light vesicle membranes isolated from healthy and HD iPSC-derived neurons, we found significant changes in the proteome and kinome of signal transduction, neuronal translation, trafficking, and axon guidance-related processes. Through a combination of in vitro kinase assays, Drosophila genetics, and pharmacological inhibitors, we identified that GSK3β and ERK1 phosphorylate HTT and that these events play distinct and opposing roles during HD with inhibition of GSK3β decreasing polyQ-mediated axonal transport defects and neuronal cell death, while inhibition of ERK enhancing these phenotypes. Together, this work proposes two novel pathways in which GSK3β phosphorylation events exacerbate and ERK phosphorylation events mitigate HD-dependent neuronal dysfunction highlighting a highly druggable pathway for targeted therapeutics using already available small molecules.
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Affiliation(s)
- Thomas J Krzystek
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Rasika Rathnayake
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Jia Zeng
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Jing Huang
- Neuroscience Program, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Gary Iacobucci
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Michael C Yu
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, USA.
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2
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Zhang S, Wang S, Yang Z, Li Y, Li J, Chen X, Yao H, Zheng Z, Guo X. Leucine 7 is a key residue for mutant huntingtin-induced mitochondrial pathology and neurotoxicity in Huntington's disease. J Biol Chem 2025; 301:108297. [PMID: 39947473 PMCID: PMC11930128 DOI: 10.1016/j.jbc.2025.108297] [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: 09/23/2024] [Revised: 01/16/2025] [Accepted: 02/04/2025] [Indexed: 03/09/2025] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of CAG repeats in exon 1 of the HTT gene. Mutant huntingtin (mHTT) associates with mitochondria, resulting in mitochondrial dysfunction and neuronal cell death. However, the underlying molecular mechanisms remain unknown. In this study, we investigate the role of N-terminal first 17 amino acids (N17) of mHTT in regulating its mitochondrial localization. Specifically, we demonstrate that the mutation at leucine 7 of N17 domain suppresses the association of mHTT with mitochondria. Blocking mitochondrial localization of HTT exon 1 with 73 glutamine repeats (HTT-Q73) strongly ameliorates polyglutamine-induced reduction of mitochondrial membrane potential, increase of reactive oxygen species production, and decrease in NAD+/NADH ratio. We observe that HTT-Q73-mediated abnormal mitochondrial morphology, mitochondrial DNA deletion, and cell death are abolished by HTT-Q73-L7A mutation. Finally, overexpression of HTT-Q73-L7A do not cause neurodegeneration and motor dysfunction in vivo. These findings highlight the pivotal role of the L7 residue which contributes to mHTT-caused HD pathology. Targeting the L7 residue of N17 domain may be a novel therapeutic strategy to alleviate mitochondrial dysfunction and neurodegeneration in HD.
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Affiliation(s)
- Shengrong Zhang
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shengda Wang
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zeyue Yang
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuanbo Li
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jinping Li
- Department of Anesthesiology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xushen Chen
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hao Yao
- Department of Anesthesiology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Zhilong Zheng
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Xing Guo
- Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China; State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China; The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China; Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu, China.
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3
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Yablonska S, Strohlein CE, Baranov SV, Yeh SM, Patel A, Singh T, Jauhari A, Kim J, Khattar NK, Li F, Wang X, Chang YF, Lee CYD, Yang XW, Carlisle DL, Friedlander RM. Regulation of Mutant Huntingtin Mitochondrial Toxicity by Phosphomimetic Mutations within Its N-Terminal Region. J Neurosci 2025; 45:e1254242024. [PMID: 39779371 PMCID: PMC11841767 DOI: 10.1523/jneurosci.1254-24.2024] [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: 07/02/2024] [Revised: 11/08/2024] [Accepted: 11/25/2024] [Indexed: 01/11/2025] Open
Abstract
Huntington's disease (HD), a neurodegenerative disease, affects approximately 30,000 people in the United States, with 200,000 more at risk. Mitochondrial dysfunction caused by mutant huntingtin (mHTT) drives early HD pathophysiology. mHTT binds the translocase of the mitochondrial inner membrane (TIM23) complex, inhibiting mitochondrial protein import and altering the mitochondrial proteome. The 17 aa HTT N-terminal sequence (N17) acts as a regulatory domain in HD pathogenesis; phosphomimetic modification of serines 13 and 16 of the N17 domain impacts subcellular localization and degradation and ameliorates toxicity in mouse and cell models of HD. Using cellular and mouse (either sex) HD models, we investigated the mechanisms by which HTT phosphorylation affects intracellular localization. We demonstrate that introducing phosphomimetic mutations within the mHTT fragment N17 domain decreased TIM23 binding affinity and reduced inhibition of mHTT-mediated mitochondrial protein import. BACHD-SD mice expressing full-length mHTT harboring the same two N17 phosphomimetic mutations have an ameliorated HD-like phenotype as compared with mice expressing mHTT. Consistent with reduced toxicity in vivo, we found that the amount of full-length mHTT in the brain mitochondria of BACHD-SD transgenic mice is less when the mHTT has two phosphomimetic mutations. To complement the relevance of the phosphomimetic HTT findings, endogenous N17 phospho-mHTT is less likely to translocate to the mitochondria compared with nonphosphorylated mHTT. We demonstrate that phosphorylation of mHTT at serines 13 and 16 is critical for negatively regulating mHTT mitochondrial targeting and that reducing mHTT mitochondrial localization and binding to TIM23 results in amelioration of mHTT-induced mitochondrial and neuronal toxicity.
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Affiliation(s)
- Svitlana Yablonska
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Colleen E Strohlein
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Sergei V Baranov
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Stacy M Yeh
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Aashka Patel
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Tanisha Singh
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Abhishek Jauhari
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - JinHo Kim
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Nicolas K Khattar
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Fang Li
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Xiaomin Wang
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Yue-Fang Chang
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - C Y Daniel Lee
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience & Human Behavior at UCLA, Los Angeles, California 90095
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - X William Yang
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience & Human Behavior at UCLA, Los Angeles, California 90095
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Diane L Carlisle
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Robert M Friedlander
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
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4
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Xu H, Ajayan A, Langen R, Chen J. Pleiotropic effects of mutant huntingtin on retinopathy in two mouse models of Huntington's disease. Neurobiol Dis 2025; 205:106780. [PMID: 39736404 PMCID: PMC11837809 DOI: 10.1016/j.nbd.2024.106780] [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: 08/28/2024] [Revised: 12/19/2024] [Accepted: 12/21/2024] [Indexed: 01/01/2025] Open
Abstract
Huntington's disease (HD) is caused by the expansion of a CAG repeat, encoding a string of glutamines (polyQ) in the first exon of the huntingtin gene (HTTex1). This mutant huntingtin protein (mHTT) with extended polyQ forms aggregates in cortical and striatal neurons, causing cell damage and death. The retina is part of the central nervous system (CNS), and visual deficits and structural abnormalities in the retina of HD patients have been observed. Defects in retinal structure and function are also present in the R6/2 and R6/1 HD transgenic mouse models that contain a gene fragment to express mHTTex1. We investigated whether these defects extend to the zQ175KI mouse model which is thought to be more representative of the human condition because it was engineered to contain the extended CAG repeat within the endogenous HTT locus. We found qualitatively similar phenotypes between R6/1 and zQ175KI retinae that include the presence of mHTT aggregates in retinal neurons, cone loss, downregulation of rod signaling proteins and abnormally elongated photoreceptor connecting cilia. In addition, we present novel findings that mHTT disrupts cell polarity in the photoreceptor cell layer and the retinal pigment epithelium (RPE). Furthermore, we show that the RPE cells from R6/1 mice contain mHTT nuclear inclusions, adding to the list of non-neuronal cells with mHTT aggregates and pathology. Thus, the eye may serve as a useful system to track disease progression and to test therapeutic intervention strategies for HD.
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Affiliation(s)
- Hui Xu
- Department of Physiology & Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Anakha Ajayan
- Department of Physiology & Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Ralf Langen
- Department of Physiology & Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jeannie Chen
- Department of Physiology & Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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5
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Cho H. The N17 domain of huntingtin as a multifaceted player in Huntington's disease. Front Mol Biosci 2025; 11:1527313. [PMID: 39845903 PMCID: PMC11753208 DOI: 10.3389/fmolb.2024.1527313] [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: 11/13/2024] [Accepted: 12/19/2024] [Indexed: 01/24/2025] Open
Abstract
Huntington's disease (HD) is primarily caused by the aberrant aggregation of the N-terminal exon 1 fragment of mutant huntingtin protein (mHttex1) with expanded polyglutamine (polyQ) repeats in neurons. The first 17 amino acids of the N-terminus of Httex1 (N17 domain) immediately preceding the polyQ repeat domain are evolutionarily conserved across vertebrates and play multifaceted roles in the pathogenesis of HD. Due to its amphipathic helical properties, the N17 domain, both alone and when membrane-associated, promotes mHttEx1 aggregation. Diverse post-translational modifications (PTMs) in the N17 domain alter the aggregation state, thus modulating the cellular toxicity of mHttex1. Furthermore, the N17 domain serves as a nuclear export signal (NES) and mediates the cytoplasmic localization of mHttex1. This review summarizes the four main roles of the N17 domain in regulating HD pathology and discusses potential therapeutic approaches targeting this N17 domain to mitigate HD progression.
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Affiliation(s)
- Hyunju Cho
- Center for Biomolecular and Cellular Structure, Institute for Basic Science, Daejeon, Republic of Korea
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6
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Shi W, Li L, Zhao H, Li Z, Ma Z, Gu Q, Ye H, Jiang X, Dong Y, Qin L, Zhou H, Yu Z, Jiao Z. Targeting SHCBP1 Inhibits Tumor Progression by Restoring Ciliogenesis in Ductal Carcinoma. Cancer Res 2024; 84:4156-4172. [PMID: 39312205 DOI: 10.1158/0008-5472.can-24-1095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 07/22/2024] [Accepted: 09/18/2024] [Indexed: 12/17/2024]
Abstract
Primary cilia detect and transmit environmental signals into cells. Primary cilia are absent in a subset of ductal carcinomas characterized by distinctive biological activities, and recovery of cilia with normal functionality has been shown to have therapeutic potential in some cancer types. Therefore, elucidation of the underlying mechanism and clinical significance of ciliary loss in ductal carcinomas could help develop effective treatment strategies. Here, we identified a link between Shc1-binding protein (SHCBP1) and cilia in ductal carcinomas. Shcbp1 knockout in transgenic mice profoundly impeded tumor progression and metastasis, prolonging survival. Single-cell transcriptome analysis revealed a functional connection between SHCBP1 deficiency and increased tumor ciliogenesis. SHCBP1 ablation restored ciliogenesis in unciliated ductal carcinoma by promoting the proximity between the midbody remnant (MBR) and centrosome through enhanced Rab8 GTPase activity and Rab8GTP positioning within the MBR. Inhibition of tumor progression by SHCBP1 loss relied on the recovery of ciliogenesis. Analysis of a large cohort of patients with ductal carcinoma revealed a negative correlation between SHCBP1-induced ciliary loss and patient prognosis. Restoring ciliogenesis via SHCBP1 ablation elicited therapeutic effects in patient-derived xenograft models. Together, this study delineates that induction of MBR-centrosome proximity through SHCBP1-deficiency reactivates ciliogenesis, offering unique opportunities for the treatment of unciliated ductal carcinomas. Significance: SHCBP1 depletion rescues tumor ciliogenesis by enhancing Rab8 GTPase activity to restore the proximity of the midbody remnant to the centrosome, which impedes progression of ductal carcinomas and suggests potential therapeutic strategies.
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Affiliation(s)
- Wengui Shi
- Cuiying Biomedical Research Center, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
- Biobank of Tumors from Plateau of Gansu Province, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
| | - Lianshun Li
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
| | - Huiming Zhao
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
| | - Zhengyang Li
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
| | - Zhijian Ma
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
| | - Qianlin Gu
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
| | - Huili Ye
- Cuiying Biomedical Research Center, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
- Biobank of Tumors from Plateau of Gansu Province, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
| | - Xiangyan Jiang
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
| | - Yuman Dong
- Cuiying Biomedical Research Center, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
- Biobank of Tumors from Plateau of Gansu Province, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
| | - Long Qin
- Cuiying Biomedical Research Center, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
- Biobank of Tumors from Plateau of Gansu Province, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
| | - Huinian Zhou
- The Department of General Surgery, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
| | - Zeyuan Yu
- The Department of General Surgery, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
| | - Zuoyi Jiao
- Biobank of Tumors from Plateau of Gansu Province, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, People's Republic of China
- The Department of General Surgery, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, People's Republic of China
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7
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Truant R, Harding RJ, Neuman K, Maiuri T. Revisiting huntingtin activity and localization signals in the context of protein structure. J Huntingtons Dis 2024; 13:419-430. [PMID: 39973382 DOI: 10.1177/18796397241295303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2025]
Abstract
Protein localization signals and activity motifs have been defined within huntingtin since 2003. Advances in technology in protein structure determination by cryo-electron microscopy (EM) have led to 2.6 Å resolution structures of huntingtin and HAP40 for the majority of the protein, although structure of the amino terminus with the polyglutamine expansion remains elusive in the context of full-length huntingtin. Recent advances in protein modeling using neural network algorithms trained on a database of known protein structures has resulted in structure predictions that are useful for researchers but need experimental validation. Here, we use both structures solved by cryo-EM as well as modeling centered around experimental structural data to retrospectively revisit huntingtin protein localization signals identified prior to the cryo-EM and AI-enabled structural revolutions. We interrogate these models as well as put forward testable hypotheses of allosteric changes in huntingtin and how they could be affected by polyglutamine expansion. We also extended this methodology to another polyglutamine disease protein, ataxin-1, expanded in Spinocerebellar Ataxia Type 1 (SCA1).
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Affiliation(s)
- Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Rachel J Harding
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada
- Structural Genomics Consortium, University of Toronto, Toronto, Canada
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Kaitlyn Neuman
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Tamara Maiuri
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
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8
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Maiuri T, Bazan CB, Harding RJ, Begeja N, Kam TI, Byrne LM, Rodrigues FB, Warner MM, Neuman K, Mansoor M, Badiee M, Dasovich M, Wang K, Thompson LM, Leung AKL, Andres SN, Wild EJ, Dawson TM, Dawson VL, Arrowsmith CH, Truant R. Poly ADP-ribose signaling is dysregulated in Huntington disease. Proc Natl Acad Sci U S A 2024; 121:e2318098121. [PMID: 39331414 PMCID: PMC11459172 DOI: 10.1073/pnas.2318098121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 08/18/2024] [Indexed: 09/28/2024] Open
Abstract
Huntington disease (HD) is a genetic neurodegenerative disease caused by cytosine, adenine, guanine (CAG) expansion in the Huntingtin (HTT) gene, translating to an expanded polyglutamine tract in the HTT protein. Age at disease onset correlates to CAG repeat length but varies by decades between individuals with identical repeat lengths. Genome-wide association studies link HD modification to DNA repair and mitochondrial health pathways. Clinical studies show elevated DNA damage in HD, even at the premanifest stage. A major DNA repair node influencing neurodegenerative disease is the PARP pathway. Accumulation of poly adenosine diphosphate (ADP)-ribose (PAR) has been implicated in Alzheimer and Parkinson diseases, as well as cerebellar ataxia. We report that HD mutation carriers have lower cerebrospinal fluid PAR levels than healthy controls, starting at the premanifest stage. Human HD induced pluripotent stem cell-derived neurons and patient-derived fibroblasts have diminished PAR response in the context of elevated DNA damage. We have defined a PAR-binding motif in HTT, detected HTT complexed with PARylated proteins in human cells during stress, and localized HTT to mitotic chromosomes upon inhibition of PAR degradation. Direct HTT PAR binding was measured by fluorescence polarization and visualized by atomic force microscopy at the single molecule level. While wild-type and mutant HTT did not differ in their PAR binding ability, purified wild-type HTT protein increased in vitro PARP1 activity while mutant HTT did not. These results provide insight into an early molecular mechanism of HD, suggesting possible targets for the design of early preventive therapies.
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Affiliation(s)
- Tamara Maiuri
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
| | - Carlos Barba Bazan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
| | - Rachel J. Harding
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, TorontoONM5S 3M2, Canada
- Structural Genomics Consortium, University of Toronto, Toronto, ONM5G 1L7, Canada
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Nola Begeja
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
| | - Tae-In Kam
- Neurodegeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore,MD21205
| | - Lauren M. Byrne
- University College London Huntington Disease Centre, University College London Queen Square Institute of Neurology, University College London, LondonWC1N 3BG, United Kingdom
| | - Filipe B. Rodrigues
- University College London Huntington Disease Centre, University College London Queen Square Institute of Neurology, University College London, LondonWC1N 3BG, United Kingdom
| | - Monica M. Warner
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4L8, Canada
| | - Kaitlyn Neuman
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
| | - Muqtasid Mansoor
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
| | - Mohsen Badiee
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21205
| | - Morgan Dasovich
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21205
| | - Keona Wang
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
| | - Leslie M. Thompson
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA92868
| | - Anthony K. L. Leung
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21205
- Department of Molecular Biology and Genetics, School of Medicine, Johns Hopkins University, Baltimore,MD21205
- Department of Genetic Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD21205
- Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD21205
| | - Sara N. Andres
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4L8, Canada
| | - Edward J. Wild
- University College London Huntington Disease Centre, University College London Queen Square Institute of Neurology, University College London, LondonWC1N 3BG, United Kingdom
| | - Ted M. Dawson
- Neurodegeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore,MD21205
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Valina L. Dawson
- Neurodegeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore,MD21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Cheryl H. Arrowsmith
- Structural Genomics Consortium, University of Toronto, Toronto, ONM5G 1L7, Canada
- Princess Margaret Cancer Centre, University of Toronto, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 1L7, Canada
| | - Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 3Z5, Canada
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9
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Yadav M, Harding RJ, Li T, Xu X, Gall-Duncan T, Khan M, Bardile CF, Sequiera GL, Duan S, Chandrasekaran R, Pan A, Bu J, Yamazaki T, Hirose T, Prinos P, Tippett L, Turner C, Curtis MA, Faull RL, Pouladi MA, Pearson CE, He HH, Arrowsmith CH. Huntingtin is an RNA binding protein and participates in NEAT1-mediated paraspeckles. SCIENCE ADVANCES 2024; 10:eado5264. [PMID: 39028820 PMCID: PMC11259171 DOI: 10.1126/sciadv.ado5264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 06/14/2024] [Indexed: 07/21/2024]
Abstract
Huntingtin protein, mutated in Huntington's disease, is implicated in nucleic acid-mediated processes, yet the evidence for direct huntingtin-nucleic acid interaction is limited. Here, we show wild-type and mutant huntingtin copurify with nucleic acids, primarily RNA, and interact directly with G-rich RNAs in in vitro assays. Huntingtin RNA-immunoprecipitation sequencing from patient-derived fibroblasts and neuronal progenitor cells expressing wild-type and mutant huntingtin revealed long noncoding RNA NEAT1 as a significantly enriched transcript. Altered NEAT1 levels were evident in Huntington's disease cells and postmortem brain tissues, and huntingtin knockdown decreased NEAT1 levels. Huntingtin colocalized with NEAT1 in paraspeckles, and we identified a high-affinity RNA motif preferred by huntingtin. This study highlights NEAT1 as a huntingtin interactor, demonstrating huntingtin's involvement in RNA-mediated functions and paraspeckle regulation.
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Affiliation(s)
- Manisha Yadav
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Rachel J. Harding
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Tiantian Li
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Xin Xu
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Terence Gall-Duncan
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Mahreen Khan
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Costanza Ferrari Bardile
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, Djavad Mowafaghian Centre for Brain Health, Edwin S. H. Leong Centre for Healthy Aging, Faculty of Medicine, University of British Columbia, British Columbia Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Glen L. Sequiera
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, Djavad Mowafaghian Centre for Brain Health, Edwin S. H. Leong Centre for Healthy Aging, Faculty of Medicine, University of British Columbia, British Columbia Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Shili Duan
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | | | - Anni Pan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Jiachuan Bu
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan
| | - Panagiotis Prinos
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Lynette Tippett
- School of Psychology, University of Auckland, Auckland, New Zealand
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Anatomical Pathology, Pathology and Laboratory Medicine, Auckland City Hospital, Auckland, New Zealand
| | - Maurice A. Curtis
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Richard L.M. Faull
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Mahmoud A. Pouladi
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, Djavad Mowafaghian Centre for Brain Health, Edwin S. H. Leong Centre for Healthy Aging, Faculty of Medicine, University of British Columbia, British Columbia Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Christopher E. Pearson
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Housheng Hansen He
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Cheryl H. Arrowsmith
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
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10
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Pandey NK, Varkey J, Ajayan A, George G, Chen J, Langen R. Fluorescent protein tagging promotes phase separation and alters the aggregation pathway of huntingtin exon-1. J Biol Chem 2024; 300:105585. [PMID: 38141760 PMCID: PMC10825056 DOI: 10.1016/j.jbc.2023.105585] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/25/2023] Open
Abstract
Fluorescent protein tags are convenient tools for tracking the aggregation states of amyloidogenic or phase separating proteins, but the effect of the tags is often not well understood. Here, we investigated the impact of a C-terminal red fluorescent protein (RFP) tag on the phase separation of huntingtin exon-1 (Httex1), an N-terminal portion of the huntingtin protein that aggregates in Huntington's disease. We found that the RFP-tagged Httex1 rapidly formed micron-sized, phase separated states in the presence of a crowding agent. The formed structures had a rounded appearance and were highly dynamic according to electron paramagnetic resonance and fluorescence recovery after photobleaching, suggesting that the phase separated state was largely liquid in nature. Remarkably, the untagged protein did not undergo any detectable liquid condensate formation under the same conditions. In addition to strongly promoting liquid-liquid phase separation, the RFP tag also facilitated fibril formation, as the tag-dependent liquid condensates rapidly underwent a liquid-to-solid transition. The rate of fibril formation under these conditions was significantly faster than that of the untagged protein. When expressed in cells, the RFP-tagged Httex1 formed larger aggregates with different antibody staining patterns compared to untagged Httex1. Collectively, these data reveal that the addition of a fluorescent protein tag significantly impacts liquid and solid phase separations of Httex1 in vitro and leads to altered aggregation in cells. Considering that the tagged Httex1 is commonly used to study the mechanisms of Httex1 misfolding and toxicity, our findings highlight the importance to validate the conclusions with untagged protein.
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Affiliation(s)
- Nitin K Pandey
- Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jobin Varkey
- Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Anakha Ajayan
- Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Gincy George
- Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jeannie Chen
- Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Ralf Langen
- Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA; Biochemistry and Molecular Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
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11
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Cariulo C, Martufi P, Verani M, Toledo-Sherman L, Lee R, Dominguez C, Petricca L, Caricasole A. IKBKB reduces huntingtin aggregation by phosphorylating serine 13 via a non-canonical IKK pathway. Life Sci Alliance 2023; 6:e202302006. [PMID: 37553253 PMCID: PMC10410066 DOI: 10.26508/lsa.202302006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/10/2023] Open
Abstract
N-terminal phosphorylation at residues T3 and S13 is believed to have important beneficial implications for the biological and pathological properties of mutant huntingtin, where inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB) was identified as a candidate regulator of huntingtin N-terminal phosphorylation. The paucity of mechanistic information on IKK pathways, together with the lack of sensitive methods to quantify endogenous huntingtin phosphorylation, prevented detailed study of the role of IKBKB in Huntington's disease. Using novel ultrasensitive assays, we demonstrate that IKBKB can regulate endogenous S13 huntingtin phosphorylation in a manner, dependent on its kinase activity and known regulators. We found that the ability of IKBKB to phosphorylate endogenous huntingtin S13 is mediated through a non-canonical interferon regulatory factor3-mediated IKK pathway, distinct from the established involvement of IKBKB in mutant huntingtin's pathological mechanisms mediated via the canonical pathway. Furthermore, increased huntingtin S13 phosphorylation by IKBKB resulted in decreased aggregation of mutant huntingtin in cells, again dependent on its kinase activity. These findings point to a non-canonical IKK pathway linking S13 huntingtin phosphorylation to the pathological properties of mutant huntingtin aggregation, thought to be significant to Huntington's disease.
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Affiliation(s)
- Cristina Cariulo
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Paola Martufi
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Margherita Verani
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Leticia Toledo-Sherman
- Rainwatercf.org Tau Consortium, Rainwater Charitable Foundation, Fort Worth, TX, USA
- UCLA, Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
| | - Ramee Lee
- CHDI Management/CHDI Foundation, Princeton, NJ, USA
| | | | - Lara Petricca
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Andrea Caricasole
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
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12
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Liu L, Tong H, Sun Y, Chen X, Yang T, Zhou G, Li XJ, Li S. Huntingtin Interacting Proteins and Pathological Implications. Int J Mol Sci 2023; 24:13060. [PMID: 37685866 PMCID: PMC10488016 DOI: 10.3390/ijms241713060] [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: 07/06/2023] [Revised: 08/08/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Huntington's disease (HD) is caused by an expansion of a CAG repeat in the gene that encodes the huntingtin protein (HTT). The exact function of HTT is still not fully understood, and previous studies have mainly focused on identifying proteins that interact with HTT to gain insights into its function. Numerous HTT-interacting proteins have been discovered, shedding light on the functions and structure of HTT. Most of these proteins interact with the N-terminal region of HTT. Among the various HTT-interacting proteins, huntingtin-associated protein 1 (HAP1) and HTT-interacting protein 1 (HIP1) have been extensively studied. Recent research has uncovered differences in the distribution of HAP1 in monkey and human brains compared with mice. This finding suggests that there may be species-specific variations in the regulation and function of HTT-interacting proteins. Understanding these differences could provide crucial insights into the development of HD. In this review, we will focus on the recent advancements in the study of HTT-interacting proteins, with particular attention to the differential distributions of HTT and HAP1 in larger animal models.
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Affiliation(s)
| | | | | | | | | | | | | | - Shihua Li
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of Central Nervous System Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510623, China; (L.L.); (H.T.); (Y.S.); (X.C.); (T.Y.); (G.Z.); (X.-J.L.)
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13
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Saha G, Ghosh S, Dubey VK, Saudagar P. Gene Alterations Induced by Glutamine (Q) Encoding CAG Repeats Associated with Neurodegeneration. Methods Mol Biol 2023; 2575:3-23. [PMID: 36301468 DOI: 10.1007/978-1-0716-2716-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Several studies have been reported linking the role of polyglutamine (polyQ) disease-associated proteins with altered gene regulation induced by an unstable trinucleotide (CAG) repeat. Owing to their dynamic nature of expansion, these DNA repeats form secondary structures interfering with the normal cellular mechanisms like replication and transcription and, thereby, have become the underlying cause of numerous neurodegenerative disorders involving mental retardation and/or muscular or neuronal degeneration. Despite the widespread expression of the disease-causing protein, specific subsets of neurons are susceptible to specific patterns of inheritance and clinical symptoms. Although this cell-type selectivity is still elusive and less understood, it has been found that aberrant transcriptional regulation is one of the primary causes of polyQ diseases where the functions of histone-modifying complexes are disrupted. Besides, epigenetic modifications play a critical role in the pathogenesis of these diseases. In this chapter, we will be delving into how these polyQ repeats induce the self-assembly and aggregation of altered carrier proteins based on gene alterations, causing neuronal toxicity and cellular deaths. Besides, genomic instability in CAG repeats due to altered chromatin-related enzymes will be highlighted, along with epigenetic changes present in many polyQ disorders. Understanding the underlying molecular mechanisms in the root cause of these disorders will culminate in identifying therapeutic approaches for the treatment of these neurodegenerative disorders.
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Affiliation(s)
- Gundappa Saha
- Department of Basic & Translational Sciences, Penn Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sukanya Ghosh
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Vikash Kumar Dubey
- School of Biochemical Engineering, Indian Institute of Technology BHU, Varanasi, Uttar Pradesh, India
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology, Warangal, Telangana, India.
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14
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Kim H, Gomez-Pastor R. HSF1 and Its Role in Huntington's Disease Pathology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1410:35-95. [PMID: 36396925 PMCID: PMC12001818 DOI: 10.1007/5584_2022_742] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE OF REVIEW Heat shock factor 1 (HSF1) is the master transcriptional regulator of the heat shock response (HSR) in mammalian cells and is a critical element in maintaining protein homeostasis. HSF1 functions at the center of many physiological processes like embryogenesis, metabolism, immune response, aging, cancer, and neurodegeneration. However, the mechanisms that allow HSF1 to control these different biological and pathophysiological processes are not fully understood. This review focuses on Huntington's disease (HD), a neurodegenerative disease characterized by severe protein aggregation of the huntingtin (HTT) protein. The aggregation of HTT, in turn, leads to a halt in the function of HSF1. Understanding the pathways that regulate HSF1 in different contexts like HD may hold the key to understanding the pathomechanisms underlying other proteinopathies. We provide the most current information on HSF1 structure, function, and regulation, emphasizing HD, and discussing its potential as a biological target for therapy. DATA SOURCES We performed PubMed search to find established and recent reports in HSF1, heat shock proteins (Hsp), HD, Hsp inhibitors, HSF1 activators, and HSF1 in aging, inflammation, cancer, brain development, mitochondria, synaptic plasticity, polyglutamine (polyQ) diseases, and HD. STUDY SELECTIONS Research and review articles that described the mechanisms of action of HSF1 were selected based on terms used in PubMed search. RESULTS HSF1 plays a crucial role in the progression of HD and other protein-misfolding related neurodegenerative diseases. Different animal models of HD, as well as postmortem brains of patients with HD, reveal a connection between the levels of HSF1 and HSF1 dysfunction to mutant HTT (mHTT)-induced toxicity and protein aggregation, dysregulation of the ubiquitin-proteasome system (UPS), oxidative stress, mitochondrial dysfunction, and disruption of the structural and functional integrity of synaptic connections, which eventually leads to neuronal loss. These features are shared with other neurodegenerative diseases (NDs). Currently, several inhibitors against negative regulators of HSF1, as well as HSF1 activators, are developed and hold promise to prevent neurodegeneration in HD and other NDs. CONCLUSION Understanding the role of HSF1 during protein aggregation and neurodegeneration in HD may help to develop therapeutic strategies that could be effective across different NDs.
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Affiliation(s)
- Hyuck Kim
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Rocio Gomez-Pastor
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, USA.
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15
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Sap KA, Geijtenbeek KW, Schipper-Krom S, Guler AT, Reits EA. Ubiquitin-modifying enzymes in Huntington's disease. Front Mol Biosci 2023; 10:1107323. [PMID: 36926679 PMCID: PMC10013475 DOI: 10.3389/fmolb.2023.1107323] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/16/2023] [Indexed: 02/10/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the N-terminus of the HTT gene. The CAG repeat expansion translates into a polyglutamine expansion in the mutant HTT (mHTT) protein, resulting in intracellular aggregation and neurotoxicity. Lowering the mHTT protein by reducing synthesis or improving degradation would delay or prevent the onset of HD, and the ubiquitin-proteasome system (UPS) could be an important pathway to clear the mHTT proteins prior to aggregation. The UPS is not impaired in HD, and proteasomes can degrade mHTT entirely when HTT is targeted for degradation. However, the mHTT protein is differently ubiquitinated when compared to wild-type HTT (wtHTT), suggesting that the polyQ expansion affects interaction with (de) ubiquitinating enzymes and subsequent targeting for degradation. The soluble mHTT protein is associated with several ubiquitin-modifying enzymes, and various ubiquitin-modifying enzymes have been identified that are linked to Huntington's disease, either by improving mHTT turnover or affecting overall homeostasis. Here we describe their potential mechanism of action toward improved mHTT targeting towards the proteostasis machinery.
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Affiliation(s)
- Karen A Sap
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Karlijne W Geijtenbeek
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Arzu Tugce Guler
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Eric A Reits
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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16
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White A, McGlone A, Gomez-Pastor R. Protein Kinase CK2 and Its Potential Role as a Therapeutic Target in Huntington's Disease. Biomedicines 2022; 10:1979. [PMID: 36009526 PMCID: PMC9406209 DOI: 10.3390/biomedicines10081979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022] Open
Abstract
Huntington's Disease (HD) is a devastating neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HTT gene, for which no disease modifying therapies are currently available. Much of the recent research has focused on developing therapies to directly lower HTT expression, and while promising, these therapies have presented several challenges regarding administration and efficacy. Another promising therapeutic approach is the modulation of HTT post-translational modifications (PTMs) that are dysregulated in disease and have shown to play a key role in HTT toxicity. Among all PTMs, modulation of HTT phosphorylation has been proposed as an attractive therapeutic option due to the possibility of orally administering specific kinase effectors. One of the kinases described to participate in HTT phosphorylation is Protein Kinase CK2. CK2 has recently emerged as a target for the treatment of several neurological and psychiatric disorders, although its role in HD remains controversial. While pharmacological studies in vitro inhibiting CK2 resulted in reduced HTT phosphorylation and increased toxicity, genetic approaches in mouse models of HD have provided beneficial effects. In this review we discuss potential therapeutic approaches related to the manipulation of HTT-PTMs with special emphasis on the role of CK2 as a therapeutic target in HD.
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Affiliation(s)
| | | | - Rocio Gomez-Pastor
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
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17
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Nag N, Tripathi T. Tau-FG-nucleoporin98 interaction and impaired nucleocytoplasmic transport in Alzheimer's disease. Brief Funct Genomics 2022; 22:161-167. [PMID: 35923096 DOI: 10.1093/bfgp/elac022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/29/2022] [Accepted: 07/11/2022] [Indexed: 11/14/2022] Open
Abstract
An emerging pathophysiology associated with the neurodegenerative Alzheimer's disease (AD) is the impairment of nucleocytoplasmic transport (NCT). The impairment can originate from damage to the nuclear pore complex (NPC) or other factors involved in NCT. The phenylalanine-glycine nucleoporins (FG-Nups) form a crucial component of the NPC, which is central to NCT. Recent discoveries have highlighted that the neuropathological protein tau is involved in direct interactions with the FG-Nups and impairment of the NCT process. Targeting such interactions may lead to the identification of novel interaction inhibitors and offer new therapeutic alternatives for the treatment of AD. This review highlights recent findings associated with impaired NCT in AD and the interaction between tau and the FG-Nups.
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Affiliation(s)
- Niharika Nag
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Timir Tripathi
- Regional Director's Office, Indira Gandhi National Open University (IGNOU), Regional Centre Kohima, Kenuozou, Kohima 797001, India
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18
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Podvin S, Rosenthal SB, Poon W, Wei E, Fisch KM, Hook V. Mutant Huntingtin Protein Interaction Map Implicates Dysregulation of Multiple Cellular Pathways in Neurodegeneration of Huntington's Disease. J Huntingtons Dis 2022; 11:243-267. [PMID: 35871359 PMCID: PMC9484122 DOI: 10.3233/jhd-220538] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a genetic neurodegenerative disease caused by trinucleotide repeat (CAG) expansions in the human HTT gene encoding the huntingtin protein (Htt) with an expanded polyglutamine tract. OBJECTIVE HD models from yeast to transgenic mice have investigated proteins interacting with mutant Htt that may initiate molecular pathways of cell death. There is a paucity of datasets of published Htt protein interactions that include the criteria of 1) defining fragments or full-length Htt forms, 2) indicating the number of poly-glutamines of the mutant and wild-type Htt forms, and 3) evaluating native Htt interaction complexes. This research evaluated such interactor data to gain understanding of Htt dysregulation of cellular pathways. METHODS Htt interacting proteins were compiled from the literature that meet our criteria and were subjected to network analysis via clustering, gene ontology, and KEGG pathways using rigorous statistical methods. RESULTS The compiled data of Htt interactors found that both mutant and wild-type Htt interact with more than 2,971 proteins. Application of a community detection algorithm to all known Htt interactors identified significant signal transduction, membrane trafficking, chromatin, and mitochondrial clusters, among others. Binomial analyses of a subset of reported protein interactor information determined that chromatin organization, signal transduction and endocytosis were diminished, while mitochondria, translation and membrane trafficking had enriched overall edge effects. CONCLUSION The data support the hypothesis that mutant Htt disrupts multiple cellular processes causing toxicity. This dataset is an open resource to aid researchers in formulating hypotheses of HD mechanisms of pathogenesis.
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Affiliation(s)
- Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Sara Brin Rosenthal
- Center for Computational Biology & Bioinformatics, University of California, San Diego, La Jolla, CA, USA
| | - William Poon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Enlin Wei
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Kathleen M Fisch
- Center for Computational Biology & Bioinformatics, University of California, San Diego, La Jolla, CA, USA.,Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA.,Department of Neuroscience and Dept of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA, USA
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19
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Zhang L, Kang H, Perez-Aguilar JM, Zhou R. Possible Co-Evolution of Polyglutamine and Polyproline in Huntingtin Protein: Proline-Rich Domain as Transient Folding Chaperone. J Phys Chem Lett 2022; 13:6331-6341. [PMID: 35796410 DOI: 10.1021/acs.jpclett.2c01184] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Huntington's disease is an inherited neurodegenerative disorder caused by the overduplication of CAG repeats in the Huntingtin gene. Recent findings revealed that among the orthologs, the expansion of CAG repeats (polyQ) in the Huntingtin gene occurs in tandem with the duplication of CCG repeats (polyP). However, the molecular mechanism of this possible co-evolution remains unknown. We examined the structures of Huntingtin exon 1 (HttEx1) from six species along with five designed mutants. We found that the polyP segments "chaperone" the rest of the HttEx1 by forming ad hoc polyP binding grooves. Such a process elongates the otherwise poorly solvated polyQ domain, while modulating its secondary structure propensity from β-strands to α-helices. This chaperoning effect is achieved mostly through transient hydrogen bond interactions between polyP and the rest of HttEx1, resulting in a striking golden ratio of ∼2:1 between the chain lengths of polyQ and polyP.
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Affiliation(s)
- Leili Zhang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Hongsuk Kang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Jose Manuel Perez-Aguilar
- School of Chemical Sciences, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | - Ruhong Zhou
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
- Institute of Quantitative Biology, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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20
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Babi M, Neuman K, Peng CY, Maiuri T, Suart CE, Truant R. Recent Microscopy Advances and the Applications to Huntington’s Disease Research. J Huntingtons Dis 2022; 11:269-280. [PMID: 35848031 PMCID: PMC9484089 DOI: 10.3233/jhd-220536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Huntingtin is a 3144 amino acid protein defined as a scaffold protein with many intracellular locations that suggest functions in these compartments. Expansion of the CAG DNA tract in the huntingtin first exon is the cause of Huntington’s disease. An important tool in understanding the biological functions of huntingtin is molecular imaging at the single-cell level by microscopy and nanoscopy. The evolution of these technologies has accelerated since the Nobel Prize in Chemistry was awarded in 2014 for super-resolution nanoscopy. We are in a new era of light imaging at the single-cell level, not just for protein location, but also for protein conformation and biochemical function. Large-scale microscopy-based screening is also being accelerated by a coincident development of machine-based learning that offers a framework for truly unbiased data acquisition and analysis at very large scales. This review will summarize the newest technologies in light, electron, and atomic force microscopy in the context of unique challenges with huntingtin cell biology and biochemistry.
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Affiliation(s)
- Mouhanad Babi
- McMaster Centre for Advanced Light Microscopy (CALM) McMaster University, Hamilton, Canada
| | - Kaitlyn Neuman
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Christina Y. Peng
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Tamara Maiuri
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Celeste E. Suart
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
- McMaster Centre for Advanced Light Microscopy (CALM) McMaster University, Hamilton, Canada
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21
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Adegbuyiro A, Stonebraker AR, Sedighi F, Fan CK, Hodges B, Li P, Valentine SJ, Legleiter J. Oxidation Promotes Distinct Huntingtin Aggregates in the Presence and Absence of Membranes. Biochemistry 2022; 61:1517-1530. [PMID: 35759798 DOI: 10.1021/acs.biochem.2c00212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expansion of a polyglutamine (polyQ) domain within the first exon of the huntingtin (htt) protein is the underlying cause of Huntington's disease, a genetic neurodegenerative disorder. PolyQ expansion triggers htt aggregation into oligomers, fibrils, and inclusions. The 17 N-terminal amino acids (Nt17) of htt-exon1, which directly precede the polyQ domain enhances polyQ fibrillization and functions as a lipid-binding domain. A variety of post-translational modifications occur within Nt17, including oxidation of two methionine residues. Here, the impact of oxidation within Nt17 on htt aggregation both in the presence and absence of lipid membranes was investigated. Treatment with hydrogen peroxide (H2O2) reduced fibril formation in a dose-dependent manner, resulting in shorter fibrils and an increased oligomer population. With excessive H2O2 treatments, fibrils developed a unique morphological feature around their periphery. In the presence of total brain lipid vesicles, H2O2 impacted fibrillization in a similar manner. That is, oligomerization was promoted at the expense of fibril elongation. The interaction of unoxidized and oxidized htt with supported lipid bilayers was directly observed using in situ atomic force microscopy. Without oxidation, granular htt aggregates developed on the bilayer surface. However, in the presence of H2O2, distinct plateau-like regions initially developed on the bilayer surface that gave way to rougher patches containing granular aggregates. Collectively, these observations suggest that oxidation of methionine residues within Nt17 plays a crucial role in both the aggregation of htt and its ability to interact with lipid surfaces.
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Affiliation(s)
- Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Caleb K Fan
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Breanna Hodges
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Peng Li
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States
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22
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Harding RJ, Deme JC, Hevler JF, Tamara S, Lemak A, Cantle JP, Szewczyk MM, Begeja N, Goss S, Zuo X, Loppnau P, Seitova A, Hutchinson A, Fan L, Truant R, Schapira M, Carroll JB, Heck AJR, Lea SM, Arrowsmith CH. Huntingtin structure is orchestrated by HAP40 and shows a polyglutamine expansion-specific interaction with exon 1. Commun Biol 2021; 4:1374. [PMID: 34880419 PMCID: PMC8654980 DOI: 10.1038/s42003-021-02895-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022] Open
Abstract
Huntington's disease results from expansion of a glutamine-coding CAG tract in the huntingtin (HTT) gene, producing an aberrantly functioning form of HTT. Both wildtype and disease-state HTT form a hetero-dimer with HAP40 of unknown functional relevance. We demonstrate in vivo and in cell models that HTT and HAP40 cellular abundance are coupled. Integrating data from a 2.6 Å cryo-electron microscopy structure, cross-linking mass spectrometry, small-angle X-ray scattering, and modeling, we provide a near-atomic-level view of HTT, its molecular interaction surfaces and compacted domain architecture, orchestrated by HAP40. Native mass spectrometry reveals a remarkably stable hetero-dimer, potentially explaining the cellular inter-dependence of HTT and HAP40. The exon 1 region of HTT is dynamic but shows greater conformational variety in the polyglutamine expanded mutant than wildtype exon 1. Our data provide a foundation for future functional and drug discovery studies targeting Huntington's disease and illuminate the structural consequences of HTT polyglutamine expansion.
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Affiliation(s)
- Rachel J Harding
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada.
| | - Justin C Deme
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Johannes F Hevler
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Sem Tamara
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Alexander Lemak
- Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Jeffrey P Cantle
- Behavioral Neuroscience Program, Department of Psychology, Western Washington University, Bellingham, WA, 98225, USA
| | - Magdalena M Szewczyk
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Nola Begeja
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Siobhan Goss
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Xiaobing Zuo
- X-ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Peter Loppnau
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Alma Seitova
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Ashley Hutchinson
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Lixin Fan
- Basic Science Program, Frederick National Laboratory for Cancer Research, SAXS Core of NCI, National Institutes of Health, Frederick, MD, 21701, USA
| | - Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Matthieu Schapira
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jeffrey B Carroll
- Behavioral Neuroscience Program, Department of Psychology, Western Washington University, Bellingham, WA, 98225, USA
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Cheryl H Arrowsmith
- Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada.
- Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada.
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23
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Pasha T, Zatorska A, Sharipov D, Rogelj B, Hortobágyi T, Hirth F. Karyopherin abnormalities in neurodegenerative proteinopathies. Brain 2021; 144:2915-2932. [PMID: 34019093 PMCID: PMC8194669 DOI: 10.1093/brain/awab201] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/08/2021] [Accepted: 05/11/2021] [Indexed: 11/12/2022] Open
Abstract
Neurodegenerative proteinopathies are characterized by progressive cell loss that is preceded by the mislocalization and aberrant accumulation of proteins prone to aggregation. Despite their different physiological functions, disease-related proteins like tau, α-synuclein, TAR DNA binding protein-43, fused in sarcoma and mutant huntingtin, all share low complexity regions that can mediate their liquid-liquid phase transitions. The proteins' phase transitions can range from native monomers to soluble oligomers, liquid droplets and further to irreversible, often-mislocalized aggregates that characterize the stages and severity of neurodegenerative diseases. Recent advances into the underlying pathogenic mechanisms have associated mislocalization and aberrant accumulation of disease-related proteins with defective nucleocytoplasmic transport and its mediators called karyopherins. These studies identify karyopherin abnormalities in amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's disease, and synucleinopathies including Parkinson's disease and dementia with Lewy bodies, that range from altered expression levels to the subcellular mislocalization and aggregation of karyopherin α and β proteins. The reported findings reveal that in addition to their classical function in nuclear import and export, karyopherins can also act as chaperones by shielding aggregation-prone proteins against misfolding, accumulation and irreversible phase-transition into insoluble aggregates. Karyopherin abnormalities can, therefore, be both the cause and consequence of protein mislocalization and aggregate formation in degenerative proteinopathies. The resulting vicious feedback cycle of karyopherin pathology and proteinopathy identifies karyopherin abnormalities as a common denominator of onset and progression of neurodegenerative disease. Pharmacological targeting of karyopherins, already in clinical trials as therapeutic intervention targeting cancers such as glioblastoma and viral infections like COVID-19, may therefore represent a promising new avenue for disease-modifying treatments in neurodegenerative proteinopathies.
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Affiliation(s)
- Terouz Pasha
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
| | - Anna Zatorska
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
| | - Daulet Sharipov
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
| | - Boris Rogelj
- Jozef Stefan Institute, Department of Biotechnology, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, 1000 Ljubljana, Slovenia
| | - Tibor Hortobágyi
- ELKH-DE Cerebrovascular and Neurodegenerative Research Group, Department of Neurology, University of Debrecen, 4032 Debrecen, Hungary
- King's College London, Department of Old Age Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, London SE5 8AF, UK
| | - Frank Hirth
- King’s College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, London SE5 9RT, UK
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24
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Nuclear and cytoplasmic huntingtin inclusions exhibit distinct biochemical composition, interactome and ultrastructural properties. Nat Commun 2021; 12:6579. [PMID: 34772920 PMCID: PMC8589980 DOI: 10.1038/s41467-021-26684-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
Despite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington's disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity.
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25
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Vieweg S, Mahul-Mellier AL, Ruggeri FS, Riguet N, DeGuire SM, Chiki A, Cendrowska U, Dietler G, Lashuel HA. The Nt17 Domain and its Helical Conformation Regulate the Aggregation, Cellular Properties and Neurotoxicity of Mutant Huntingtin Exon 1. J Mol Biol 2021; 433:167222. [PMID: 34492254 DOI: 10.1016/j.jmb.2021.167222] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/29/2022]
Abstract
Converging evidence points to the N-terminal domain comprising the first 17 amino acids of the Huntingtin protein (Nt17) as a key regulator of its aggregation, cellular properties and toxicity. In this study, we further investigated the interplay between Nt17 and the polyQ domain repeat length in regulating the aggregation and inclusion formation of exon 1 of the Huntingtin protein (Httex1). In addition, we investigated the effect of removing Nt17 or modulating its local structure on the membrane interactions, neuronal uptake, and toxicity of monomeric or fibrillar Httex1. Our results show that the polyQ and Nt17 domains synergistically modulate the aggregation propensity of Httex1 and that the Nt17 domain plays important roles in shaping the surface properties of mutant Httex1 fibrils and regulating their poly-Q-dependent growth, lateral association and neuronal uptake. Removal of Nt17 or disruption of its transient helical conformations slowed the aggregation of monomeric Httex1 in vitro, reduced inclusion formation in cells, enhanced the neuronal uptake and nuclear accumulation of monomeric Httex1 proteins, and was sufficient to prevent cell death induced by Httex1 72Q overexpression. Finally, we demonstrate that the uptake of Httex1 fibrils into primary neurons and the resulting toxicity are strongly influenced by mutations and phosphorylation events that influence the local helical propensity of Nt17. Altogether, our results demonstrate that the Nt17 domain serves as one of the key master regulators of Htt aggregation, internalization, and toxicity and represents an attractive target for inhibiting Htt aggregate formation, inclusion formation, and neuronal toxicity.
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Affiliation(s)
- Sophie Vieweg
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anne-Laure Mahul-Mellier
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Francesco S Ruggeri
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Nathan Riguet
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sean M DeGuire
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Urszula Cendrowska
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Giovanni Dietler
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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26
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Braatz EM, André EA, Liu JP, Zeitlin SO. Characterization of a Knock-In Mouse Model with a Huntingtin Exon 1 Deletion. J Huntingtons Dis 2021; 10:435-454. [PMID: 34459410 DOI: 10.3233/jhd-210494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The Huntingtin (HTT) N-terminal domains encoded by Huntingtin's (HTT) exon 1 consist of an N17 domain, the polyglutamine (polyQ) stretch and a proline-rich region (PRR). These domains are conserved in mammals and have been hypothesized to modulate HTT's functions in the developing and adult CNS, including DNA damage repair and autophagy. OBJECTIVE This study longitudinally characterizes the in vivo consequences of deleting the murine Htt N-terminal domains encoded by Htt exon 1. METHODS Knock-in mice with a deletion of Htt exon 1 sequences (HttΔE1) were generated and bred into the C57BL/6J congenic genetic background. Their behavior, DNA damage response, basal autophagy, and glutamatergic synapse numbers were evaluated. RESULTS Progeny from HttΔE1/+ intercrosses are born at the expected Mendelian frequency but with a distorted male to female ratio in both the HttΔE1/ΔE1 and Htt+/+ offspring. HttΔE1/ΔE1 adults exhibit a modest deficit in accelerating rotarod performance, and an earlier increase in cortical and striatal DNA damage with elevated neuronal pan-nuclear 53bp1 levels compared to Htt+/+ mice. However, a normal response to induced DNA damage, normal levels of basal autophagy markers, and no significant differences in corticocortical, corticostriatal, thalamocortical, or thalamostriatal synapses numbers were observed compared to controls. CONCLUSION Our results suggest that deletion of the Htt N-terminus encoded by the Htt exon 1 does not affect Htt's critical role during embryogenesis, but instead, may have a modest effect on certain motor tasks, basal levels of DNA damage in the brain, and Htt function in the testis.
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Affiliation(s)
- Elise M Braatz
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Emily A André
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jeh-Ping Liu
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Scott O Zeitlin
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
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27
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Kumar V, Singh A. Targeting N17 domain as a potential therapeutic target for the treatment of Huntington disease: An opinion. EXCLI JOURNAL 2021; 20:1086-1090. [PMID: 34267617 PMCID: PMC8278213 DOI: 10.17179/excli2021-3670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/04/2021] [Indexed: 11/24/2022]
Affiliation(s)
- Vishal Kumar
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Punjab, India.,Affiliated to IK Gujral Punjab Technical University, Jalandhar, Punjab-144603, India
| | - Arti Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Punjab, India.,Affiliated to IK Gujral Punjab Technical University, Jalandhar, Punjab-144603, India
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28
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Cryo-electron tomography provides topological insights into mutant huntingtin exon 1 and polyQ aggregates. Commun Biol 2021; 4:849. [PMID: 34239038 PMCID: PMC8266869 DOI: 10.1038/s42003-021-02360-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 06/15/2021] [Indexed: 01/27/2023] Open
Abstract
Huntington disease (HD) is a neurodegenerative trinucleotide repeat disorder caused by an expanded poly-glutamine (polyQ) tract in the mutant huntingtin (mHTT) protein. The formation and topology of filamentous mHTT inclusions in the brain (hallmarks of HD implicated in neurotoxicity) remain elusive. Using cryo-electron tomography and subtomogram averaging, here we show that mHTT exon 1 and polyQ-only aggregates in vitro are structurally heterogenous and filamentous, similar to prior observations with other methods. Yet, we find filaments in both types of aggregates under ~2 nm in width, thinner than previously reported, and regions forming large sheets. In addition, our data show a prevalent subpopulation of filaments exhibiting a lumpy slab morphology in both aggregates, supportive of the polyQ core model. This provides a basis for future cryoET studies of various aggregated mHTT and polyQ constructs to improve their structure-based modeling as well as their identification in cells without fusion tags.
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29
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Katow H, Katow T, Yoshida H, Kiyomoto M. Involvement of Huntingtin in Development and Ciliary Beating Regulation of Larvae of the Sea Urchin, Hemicentrotus pulcherrimus. Int J Mol Sci 2021; 22:5116. [PMID: 34066037 PMCID: PMC8151597 DOI: 10.3390/ijms22105116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 11/16/2022] Open
Abstract
The multiple functions of the wild type Huntington's disease protein of the sea urchin Hemicentrotus pulcherrimus (Hp-Htt) have been examined using the anti-Hp-Htt antibody (Ab) raised against synthetic oligopeptides. According to immunoblotting, Hp-Htt was detected as a single band at around the 350 kDa region at the swimming blastula stage to the prism larva stage. From the 2-arm pluteus stage (2aPL), however, an additional smaller band at the 165 kDa region appeared. Immunohistochemically, Hp-Htt was detected in the nuclei and the nearby cytoplasm of the ectodermal cells from the swimming blastula stage, and the blastocoelar cells from the mid-gastrula stage. The Ab-positive signal was converged to the ciliary band-associated strand (CBAS). There, it was accompanied by several CBAS-marker proteins in the cytoplasm, such as glutamate decarboxylase. Application of Hp-Htt morpholino (Hp-Htt-MO) has resulted in shortened larval arms, accompanied by decreased 5-bromo-2-deoxyuridin (BrdU) incorporation by the ectodermal cells of the larval arms. Hp-Htt-MO also resulted in lowered ciliary beating activity, accompanied by a disordered swirling pattern formation around the body. These Hp-Htt-MO-induced deficiencies took place after the onset of CBAS system formation at the larval arms. Thus, Hp-Htt is involved in cell proliferation and the ciliary beating pattern regulation signaling system in pluteus larvae.
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Affiliation(s)
- Hideki Katow
- Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan; (H.Y.); (M.K.)
- Research Center for Marine Biology, Tohoku University, Aomori 039-3501, Japan;
| | - Tomoko Katow
- Research Center for Marine Biology, Tohoku University, Aomori 039-3501, Japan;
| | - Hiromi Yoshida
- Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan; (H.Y.); (M.K.)
| | - Masato Kiyomoto
- Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan; (H.Y.); (M.K.)
- Marine and Coastal Research Center, Ochanomizu University, Chiba 294-0301, Japan
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30
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Doornbos C, Roepman R. Moonlighting of mitotic regulators in cilium disassembly. Cell Mol Life Sci 2021; 78:4955-4972. [PMID: 33860332 PMCID: PMC8233288 DOI: 10.1007/s00018-021-03827-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/03/2021] [Accepted: 03/27/2021] [Indexed: 02/07/2023]
Abstract
Correct timing of cellular processes is essential during embryological development and to maintain the balance between healthy proliferation and tumour formation. Assembly and disassembly of the primary cilium, the cell’s sensory signalling organelle, are linked to cell cycle timing in the same manner as spindle pole assembly and chromosome segregation. Mitotic processes, ciliary assembly, and ciliary disassembly depend on the centrioles as microtubule-organizing centres (MTOC) to regulate polymerizing and depolymerizing microtubules. Subsequently, other functional protein modules are gathered to potentiate specific protein–protein interactions. In this review, we show that a significant subset of key mitotic regulator proteins is moonlighting at the cilium, among which PLK1, AURKA, CDC20, and their regulators. Although ciliary assembly defects are linked to a variety of ciliopathies, ciliary disassembly defects are more often linked to brain development and tumour formation. Acquiring a better understanding of the overlap in regulators of ciliary disassembly and mitosis is essential in finding therapeutic targets for the different diseases and types of tumours associated with these regulators.
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Affiliation(s)
- Cenna Doornbos
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands. .,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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31
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Huang S, Dougherty LL, Avasthi P. Separable roles for RanGTP in nuclear and ciliary trafficking of a kinesin-2 subunit. J Biol Chem 2021; 296:100117. [PMID: 33234597 PMCID: PMC7948393 DOI: 10.1074/jbc.ra119.010936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023] Open
Abstract
Kinesin is part of the microtubule-binding motor protein superfamily, which serves important roles in cell division and intraorganellar transport. The heterotrimeric kinesin-2, consisting of the heterodimeric motor subunits, kinesin family member 3A/3B (KIF3A/3B), and kinesin-associated protein 3 (KAP3), is highly conserved across species from the unicellular eukaryote Chlamydomonas to humans. It plays diverse roles in cargo transport including anterograde (base to tip) trafficking in cilia. However, the molecular determinants mediating trafficking of heterotrimeric kinesin-2 itself are poorly understood. It has been previously suggested that ciliary transport is analogous to nuclear transport mechanisms. Using Chlamydomonas and human telomerase reverse transcriptase-retinal pigment epithelial cell line, we show that RanGTP, a small GTPase that dictates nuclear transport, regulates ciliary trafficking of KAP3, a key component for functional kinesin-2. We found that the armadillo-repeat region 6 to 9 (ARM6-9) of KAP3, required for its nuclear translocation, is also necessary and sufficient for its targeting to the ciliary base. Given that KAP3 is essential for cilium formation and there are the emerging roles for RanGTP/importin β in ciliary protein targeting, we further investigated the effect of RanGTP in cilium formation and maintenance. We found that precise control of RanGTP levels, revealed by different Ran mutants, is crucial for cilium formation and maintenance. Most importantly, we were able to provide orthogonal support in an algal model system that segregates RanGTP regulation of ciliary protein trafficking from its nuclear roles. Our work provides important support for the model that nuclear import mechanisms have been co-opted for independent roles in ciliary import.
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Affiliation(s)
- Shengping Huang
- Department of Ophthalmology, University of Kansas Medical Center, Kansas City, Kansas, USA.
| | - Larissa L Dougherty
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire, USA
| | - Prachee Avasthi
- Department of Ophthalmology, University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire, USA.
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32
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Groover SE, Beasley M, Ramamurthy V, Legleiter J. Phosphomimetic Mutations Impact Huntingtin Aggregation in the Presence of a Variety of Lipid Systems. Biochemistry 2020; 59:4681-4693. [PMID: 33256402 DOI: 10.1021/acs.biochem.0c00788] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of a polyglutamine (polyQ) tract in the first exon of the htt protein (htt). PolyQ expansion triggers the aggregation of htt into a variety of structures, including oligomers and fibrils. This aggregation is impacted by the first 17 N-terminal amino acids (Nt17) of htt that directly precedes the polyQ domain. Beyond impacting aggregation, Nt17 associates with lipid membranes by forming an amphipathic α-helix. Post-translational modifications within Nt17 are known to modify HD pathology, and in particular, phosphorylation at T3, S13, and/or S16 retards fibrillization and ameliorates the phenotype in HD models. Due to Nt17's propensity to interact with lipid membranes, the impact of introducing phosphomimetic mutations (T3D, S13D, and S16D) into htt-exon1 on aggregation in the presence of a variety of model lipid membranes (total brain lipid extract, 1-palmitoyl-2-oleoyl-glycero-3-phosphatidylcholine, and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-1'-rac-glycerol) was investigated. Phosphomimetic mutations altered htt's interaction with and aggregation in the presence of lipids; however, this was dependent on the lipid system.
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Affiliation(s)
- Sharon E Groover
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Visvanathan Ramamurthy
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
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33
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Hegde RN, Chiki A, Petricca L, Martufi P, Arbez N, Mouchiroud L, Auwerx J, Landles C, Bates GP, Singh-Bains MK, Dragunow M, Curtis MA, Faull RL, Ross CA, Caricasole A, Lashuel HA. TBK1 phosphorylates mutant Huntingtin and suppresses its aggregation and toxicity in Huntington's disease models. EMBO J 2020; 39:e104671. [PMID: 32757223 PMCID: PMC7459410 DOI: 10.15252/embj.2020104671] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/09/2020] [Accepted: 06/16/2020] [Indexed: 12/17/2022] Open
Abstract
Phosphorylation of the N‐terminal domain of the huntingtin (HTT) protein has emerged as an important regulator of its localization, structure, aggregation, clearance and toxicity. However, validation of the effect of bona fide phosphorylation in vivo and assessing the therapeutic potential of targeting phosphorylation for the treatment of Huntington's disease (HD) require the identification of the enzymes that regulate HTT phosphorylation. Herein, we report the discovery and validation of a kinase, TANK‐binding kinase 1 (TBK1), that efficiently phosphorylates full‐length and N‐terminal HTT fragments in vitro (at S13/S16), in cells (at S13) and in vivo. TBK1 expression in HD models (cells, primary neurons, and Caenorhabditis elegans) increases mutant HTT exon 1 phosphorylation and reduces its aggregation and cytotoxicity. We demonstrate that the TBK1‐mediated neuroprotective effects are due to phosphorylation‐dependent inhibition of mutant HTT exon 1 aggregation and an increase in autophagic clearance of mutant HTT. These findings suggest that upregulation and/or activation of TBK1 represents a viable strategy for the treatment of HD by simultaneously lowering mutant HTT levels and blocking its aggregation.
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Affiliation(s)
- Ramanath Narayana Hegde
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Lara Petricca
- Department of Neuroscience, IRBM Science Park, Rome, Italy
| | - Paola Martufi
- Department of Neuroscience, IRBM Science Park, Rome, Italy
| | - Nicolas Arbez
- Division of Neurobiology, Department of Psychiatry and Departments of Neurology, Neuroscience and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Laurent Mouchiroud
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Christian Landles
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Gillian P Bates
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Malvindar K Singh-Bains
- Centre for Brain Research, Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Mike Dragunow
- Centre for Brain Research, Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Christopher A Ross
- Division of Neurobiology, Department of Psychiatry and Departments of Neurology, Neuroscience and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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34
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Bitetto G, Di Fonzo A. Nucleo-cytoplasmic transport defects and protein aggregates in neurodegeneration. Transl Neurodegener 2020; 9:25. [PMID: 32616075 PMCID: PMC7333321 DOI: 10.1186/s40035-020-00205-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/01/2020] [Indexed: 02/06/2023] Open
Abstract
In the ongoing process of uncovering molecular abnormalities in neurodegenerative diseases characterized by toxic protein aggregates, nucleo-cytoplasmic transport defects have an emerging role. Several pieces of evidence suggest a link between neuronal protein inclusions and nuclear pore complex (NPC) damage. These processes lead to oxidative stress, inefficient transcription, and aberrant DNA/RNA maintenance. The clinical and neuropathological spectrum of NPC defects is broad, ranging from physiological aging to a suite of neurodegenerative diseases. A better understanding of the shared pathways among these conditions may represent a significant step toward dissecting their underlying molecular mechanisms, opening the way to a real possibility of identifying common therapeutic targets.
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Affiliation(s)
- Giacomo Bitetto
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Alessio Di Fonzo
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.
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35
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Goodliffe J, Rubakovic A, Chang W, Pathak D, Luebke J. Structural and functional features of medium spiny neurons in the BACHDΔN17 mouse model of Huntington's Disease. PLoS One 2020; 15:e0234394. [PMID: 32574176 PMCID: PMC7310706 DOI: 10.1371/journal.pone.0234394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 05/26/2020] [Indexed: 11/25/2022] Open
Abstract
In the BACHD mouse model of Huntington’s disease (HD), deletion of the N17 domain of the Huntingtin gene (BACHDΔN17, Q97) has been reported to lead to nuclear accumulation of mHTT and exacerbation of motor deficits, neuroinflammation and striatal atrophy (Gu et al., 2015). Here we characterized the effect of N17 deletion on dorsolateral striatal medium spiny neurons (MSNs) in BACHDΔN17 (Q97) and BACWTΔN17 (Q31) mice by comparing them to MSNs in wildtype (WT) mice. Mice were characterized on a series of motor tasks and subsequently whole cell patch clamp recordings with simultaneous biocytin filling of MSNs in in vitro striatal slices from these mice were used to comprehensively assess their physiological and morphological features. Key findings include that: Q97 mice exhibit impaired gait and righting reflexes but normal tail suspension reflexes and normal coats while Q31 mice do not differ from WT; intrinsic membrane and action potential properties are altered -but differentially so- in MSNs from Q97 and from Q31 mice; excitatory and inhibitory synaptic currents exhibit higher amplitudes in Q31 but not Q97 MSNs, while excitatory synaptic currents occur at lower frequency in Q97 than in WT and Q31 MSNs; there is a reduced total dendritic length in Q31 -but not Q97- MSNs compared to WT, while spine density and number did not differ in MSNs in the three groups. The findings that Q31 MSNs differed from Q97 and WT neurons with regard to some physiological features and structurally suggest a novel role of the N17 domain in the function of WT Htt. The motor phenotype seen in Q97 mice was less robust than that reported in an earlier study (Gu et al., 2015), and the alterations to MSN physiological properties were largely consistent with changes reported previously in a number of other mouse models of HD. Together this study indicates that N17 plays a role in the modulation of the properties of MSNs in both mHtt and WT-Htt mice, but does not markedly exacerbate HD-like pathogenesis in the BACHD model.
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Affiliation(s)
- Joseph Goodliffe
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
| | - Anastasia Rubakovic
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Wayne Chang
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Dhruba Pathak
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Jennifer Luebke
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
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36
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Sap KA, Reits EA. Strategies to Investigate Ubiquitination in Huntington's Disease. Front Chem 2020; 8:485. [PMID: 32596207 PMCID: PMC7300180 DOI: 10.3389/fchem.2020.00485] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/11/2020] [Indexed: 01/15/2023] Open
Abstract
Many neurodegenerative disorders including Huntington's Disease are hallmarked by intracellular protein aggregates that are decorated by ubiquitin and different ubiquitin ligases and deubiquitinating enzymes. The protein aggregates observed in Huntington's Disease are caused by a polyglutamine expansion in the N-terminus of the huntingtin protein (Htt). Improving the degradation of mutant Htt via the Ubiquitin Proteasome System prior to aggregation would be a therapeutic strategy to delay or prevent the onset of Huntington's Disease for which there is currently no cure. Here we examine the current approaches used to study the ubiquitination of both soluble Htt as well as insolubilized Htt present in aggregates, and we describe what is known about involved (de)ubiquitinating enzymes. Furthermore, we discuss novel methodologies to study the dynamics of Htt ubiquitination in living cells using fluorescent ubiquitin probes, to identify and quantify Htt ubiquitination by mass spectrometry-based approaches, and various approaches to identify involved ubiquitinating enzymes.
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Affiliation(s)
- Karen A Sap
- Department of Medical Biology, Amsterdam UMC, Amsterdam, Netherlands
| | - Eric A Reits
- Department of Medical Biology, Amsterdam UMC, Amsterdam, Netherlands
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37
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Ultrasensitive quantitative measurement of huntingtin phosphorylation at residue S13. Biochem Biophys Res Commun 2020; 521:549-554. [DOI: 10.1016/j.bbrc.2019.09.097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 09/22/2019] [Indexed: 11/21/2022]
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38
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Mustafa R, Kreiner G, Kamińska K, Wood AEJ, Kirsch J, Tucker KL, Parlato R. Targeted Depletion of Primary Cilia in Dopaminoceptive Neurons in a Preclinical Mouse Model of Huntington's Disease. Front Cell Neurosci 2019; 13:565. [PMID: 31920562 PMCID: PMC6936315 DOI: 10.3389/fncel.2019.00565] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/05/2019] [Indexed: 12/22/2022] Open
Abstract
Multiple pathomechanisms triggered by mutant Huntingtin (mHTT) underlie progressive degeneration of dopaminoceptive striatal neurons in Huntington’s disease (HD). The primary cilium is a membrane compartment that functions as a hub for various pathways that are dysregulated in HD, for example, dopamine (DA) receptor transmission and the mechanistic target of rapamycin (mTOR) pathway. The roles of primary cilia (PC) for the maintenance of striatal neurons and in HD progression remain unknown. Here, we investigated PC defects in vulnerable striatal neurons in a progressive model of HD, the mHTT-expressing knock-in zQ175 mice. We found that PC length is affected in striatal but not in cortical neurons, in association with the accumulation of mHTT. To explore the role of PC, we generated conditional mutant mice lacking IFT88, a component of the anterograde intraflagellar transport-B complex lacking PC in dopaminoceptive neurons. This mutation preserved the expression of the dopamine 1 receptor (D1R), and the survival of striatal neurons, but resulted in a mild increase of DA metabolites in the striatum, suggesting an imbalance of ciliary DA receptor transmission. Conditional loss of PC in zQ175 mice did not trigger astrogliosis, however, mTOR signaling was more active and resulted in a more pronounced accumulation of nuclear inclusions containing mHTT. Further studies will be required of aged mice to determine the role of aberrant ciliary function in more advanced stages of HD.
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Affiliation(s)
- Rasem Mustafa
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.,Institute of Anatomy and Cell Biology, Medical Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Grzegorz Kreiner
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Katarzyna Kamińska
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.,Jagiellonian Center for Experimental Therapeutics, Jagiellonian University, Kraków, Poland
| | - Amelia-Elise J Wood
- Department of Biomedical Sciences, Center for Excellence in the Neurosciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, United States
| | - Joachim Kirsch
- Institute of Anatomy and Cell Biology, Medical Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Kerry L Tucker
- Department of Biomedical Sciences, Center for Excellence in the Neurosciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, United States
| | - Rosanna Parlato
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.,Institute of Anatomy and Cell Biology, Medical Cell Biology, University of Heidelberg, Heidelberg, Germany
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39
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Maiuri T, Suart CE, Hung CLK, Graham KJ, Barba Bazan CA, Truant R. DNA Damage Repair in Huntington's Disease and Other Neurodegenerative Diseases. Neurotherapeutics 2019; 16:948-956. [PMID: 31364066 PMCID: PMC6985310 DOI: 10.1007/s13311-019-00768-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Recent genome-wide association studies of Huntington's disease (HD) primarily highlighted genes involved in DNA damage repair mechanisms as modifiers of age at onset and disease severity, consistent with evidence that more DNA repair genes are being implicated in late age-onset neurodegenerative diseases. This provides an exciting opportunity to advance therapeutic development in HD, as these pathways have already been under intense investigation in cancer research. Also emerging are the roles of other polyglutamine disease proteins in DNA damage repair mechanisms. A potential universal trigger of oxidative DNA damage shared in these late age-onset diseases is the increase of reactive oxygen species (ROS) in human aging, defining an age-related mechanism that has defied other hypotheses of neurodegeneration. We discuss the potential commonality of DNA damage repair pathways in HD and other neurodegenerative diseases. Potential targets for therapy that may prove beneficial across many of these diseases are also identified, defining nodes in the ataxia telangiectasia-mutated (ATM) complex, mismatch repair, and poly ADP-ribose polymerases (PARPs).
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Affiliation(s)
- T Maiuri
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - C E Suart
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - C L K Hung
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - K J Graham
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - C A Barba Bazan
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - R Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada.
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40
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Satir P, Satir BH. The conserved ancestral signaling pathway from cilium to nucleus. J Cell Sci 2019; 132:132/15/jcs230441. [PMID: 31375541 DOI: 10.1242/jcs.230441] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022] Open
Abstract
Many signaling molecules are localized to both the primary cilium and nucleus. Localization of specific transmembrane receptors and their signaling scaffold molecules in the cilium is necessary for correct physiological function. After a specific signaling event, signaling molecules leave the cilium, usually in the form of an endocytic vesicle scaffold, and move to the nucleus, where they dissociate from the scaffold and enter the nucleus to affect gene expression. This ancient pathway probably arose very early in eukaryotic evolution as the nucleus and cilium co-evolved. Because there are similarities in molecular composition of the nuclear and ciliary pores the entry and exit of proteins in both organelles rely on similar mechanisms. In this Hypothesis, we propose that the pathway is a dynamic universal cilia-based signaling pathway with some variations from protists to man. Everywhere the cilium functions as an important organelle for molecular storage of certain key receptors and selection and concentration of their associated signaling molecules that move from cilium to nucleus. This could also have important implications for human diseases such as Huntington disease.
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Affiliation(s)
- Peter Satir
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY 10461 .,B&P Nanobiology Consultants, 7 Byfield Lane, Greenwich, CT 06830, USA
| | - Birgit H Satir
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY 10461.,B&P Nanobiology Consultants, 7 Byfield Lane, Greenwich, CT 06830, USA
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41
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Tellone E, Galtieri A, Ficarra S. Reviewing Biochemical Implications of Normal and Mutated Huntingtin in Huntington's Disease. Curr Med Chem 2019; 27:5137-5158. [PMID: 31223078 DOI: 10.2174/0929867326666190621101909] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/08/2019] [Accepted: 05/22/2019] [Indexed: 12/17/2022]
Abstract
Huntingtin (Htt) is a multi-function protein of the brain. Normal Htt shows a common alpha-helical structure but conformational changes in the form with beta strands are the principal cause of Huntington's disease. Huntington's disease is a genetic neurological disorder caused by a repeated expansion of the CAG trinucleotide, causing instability in the N-terminal of the gene coding for the Huntingtin protein. The mutation leads to the abnormal expansion of the production of the polyglutamine tract (polyQ) resulting in the form of an unstable Huntingtin protein commonly referred to as mutant Huntingtin. Mutant Huntingtin is the cause of the complex neurological metabolic alteration of Huntington's disease, resulting in both the loss of all the functions of normal Huntingtin and the genesis of abnormal interactions due to the presence of this mutation. One of the problems arising from the misfolded Huntingtin is the increase in oxidative stress, which is common in many neurological diseases such as Alzheimer's, Parkinson's, Amyotrophic Lateral Sclerosis and Creutzfeldt-Jakob disease. In the last few years, the use of antioxidants had a strong incentive to find valid therapies for defence against neurodegenerations. Although further studies are needed, the use of antioxidant mixtures to counteract neuronal damages seems promising.
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Affiliation(s)
- Ester Tellone
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Antonio Galtieri
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Silvana Ficarra
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
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42
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Schultz JL, Nopoulos PC, Killoran A, Kamholz JA. Statin use and delayed onset of Huntington's disease. Mov Disord 2018; 34:281-285. [PMID: 30576007 DOI: 10.1002/mds.27591] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/31/2018] [Accepted: 11/15/2018] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND There is evidence to suggest that 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) may be beneficial in Huntington's disease (HD). OBJECTIVE This study aimed to determine if statin use was associated with delayed motor diagnosis in participants with premotor HD. METHODS Among premotor HD participants from the Enroll-HD database, statin users were propensity score matched with statin nonusers based on cytosine-adenine-guanine-age product score, cytosine-adenine-guanine repeat length, baseline age, sex, and region. A Cox regression survival analysis compared the annualized hazard ratio (HR) of receiving a motor diagnosis between the 2 groups. RESULTS The annualized HR of progressing to an HD motor diagnosis was lower in the statin users (n = 89) when compared with the statin nonusers (n = 89; HR = 0.27 [95% CI 0.18-0.50], P < .0001). CONCLUSIONS In patients with premotor HD, statin use was associated with a delayed motor diagnosis of HD. Further studies are warranted to investigate if statins would be an effective disease-modifying therapy for HD. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Jordan L Schultz
- Department of Psychiatry, Carver College of Medicine at the University of Iowa, Iowa City, Iowa, USA.,Department of Pharmaceutical Care, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.,Department of Pharmacy Practice and Science, The University of Iowa College of Pharmacy, Iowa City, Iowa, USA
| | - Peg C Nopoulos
- Department of Psychiatry, Carver College of Medicine at the University of Iowa, Iowa City, Iowa, USA.,Department of Neurology, Carver College of Medicine at the University of Iowa, Iowa City, Iowa, USA.,Stead Family Department of Pediatrics at the University of Iowa, Iowa City, Iowa, USA
| | - Annie Killoran
- Department of Neurology, Carver College of Medicine at the University of Iowa, Iowa City, Iowa, USA.,The Veteran's Affair Medical Center of Iowa City, Iowa City, Iowa, USA
| | - John A Kamholz
- Department of Psychiatry, Carver College of Medicine at the University of Iowa, Iowa City, Iowa, USA.,Department of Neurology, Carver College of Medicine at the University of Iowa, Iowa City, Iowa, USA
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43
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Son S, Bowie LE, Maiuri T, Hung CLK, Desmond CR, Xia J, Truant R. High-mobility group box 1 links sensing of reactive oxygen species by huntingtin to its nuclear entry. J Biol Chem 2018; 294:1915-1923. [PMID: 30538129 DOI: 10.1074/jbc.ra117.001440] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 12/04/2018] [Indexed: 11/06/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative, age-onset disorder caused by a CAG DNA expansion in exon 1 of the HTT gene, resulting in a polyglutamine expansion in the huntingtin protein. Nuclear accumulation of mutant huntingtin is a hallmark of HD, resulting in elevated mutant huntingtin levels in cell nuclei. Huntingtin is normally retained at the endoplasmic reticulum via its N17 amphipathic α-helix domain but is released by oxidation of Met-8 during reactive oxygen species (ROS) stress. Huntingtin enters the nucleus via an importin β1- and 2-dependent proline-tyrosine nuclear localization signal (PY-NLS), which has a unique intervening sequence in huntingtin. Here, we have identified the high-mobility group box 1 (HMGB1) protein as an interactor of the intervening sequence within the PY-NLS. Nuclear levels of HMGB1 positively correlated with varying levels of nuclear huntingtin in both HD and normal human fibroblasts. We also found that HMGB1 interacts with the huntingtin N17 region and that this interaction is enhanced by the presence of ROS and phosphorylation of critical serine residues in the N17 region. We conclude that HMGB1 is a huntingtin N17/PY-NLS ROS-dependent interactor, and this protein bridging is essential for relaying ROS sensing by huntingtin to its nuclear entry during ROS stress. ROS may therefore be a critical age-onset stress that triggers nuclear accumulation of mutant huntington in Huntington's disease.
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Affiliation(s)
- Susie Son
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Laura E Bowie
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Tamara Maiuri
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Claudia L K Hung
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Carly R Desmond
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Jianrun Xia
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Ray Truant
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
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Hung CLK, Maiuri T, Bowie LE, Gotesman R, Son S, Falcone M, Giordano JV, Gillis T, Mattis V, Lau T, Kwan V, Wheeler V, Schertzer J, Singh K, Truant R. A patient-derived cellular model for Huntington's disease reveals phenotypes at clinically relevant CAG lengths. Mol Biol Cell 2018; 29:2809-2820. [PMID: 30256717 PMCID: PMC6249865 DOI: 10.1091/mbc.e18-09-0590] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The huntingtin protein participates in several cellular processes that are disrupted when the polyglutamine tract is expanded beyond a threshold of 37 CAG DNA repeats in Huntington’s disease (HD). Cellular biology approaches to understand these functional disruptions in HD have primarily focused on cell lines with synthetically long CAG length alleles that clinically represent outliers in this disease and a more severe form of HD that lacks age onset. Patient-derived fibroblasts are limited to a finite number of passages before succumbing to cellular senescence. We used human telomerase reverse transcriptase (hTERT) to immortalize fibroblasts taken from individuals of varying age, sex, disease onset, and CAG repeat length, which we have termed TruHD cells. TruHD cells display classic HD phenotypes of altered morphology, size and growth rate, increased sensitivity to oxidative stress, aberrant adenosine diphosphate/adenosine triphosphate (ADP/ATP) ratios, and hypophosphorylated huntingtin protein. We additionally observed dysregulated reactive oxygen species (ROS)-dependent huntingtin localization to nuclear speckles in HD cells. We report the generation and characterization of a human, clinically relevant cellular model for investigating disease mechanisms in HD at the single-cell level, which, unlike transformed cell lines, maintains functions critical for huntingtin transcriptional regulation and genomic integrity.
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Affiliation(s)
- Claudia Lin-Kar Hung
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Tamara Maiuri
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Laura Erin Bowie
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Ryan Gotesman
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Susie Son
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Mina Falcone
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - James Victor Giordano
- Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114.,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Tammy Gillis
- Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114.,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Virginia Mattis
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048
| | - Trevor Lau
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Vickie Kwan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada.,Stem Cell and Cancer Research Institute, Faculty of Health Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Vanessa Wheeler
- Center for Genomic Medicine, Harvard Medical School, Boston, MA 02114.,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Jonathan Schertzer
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Karun Singh
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
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Abstract
The 25 years since the identification of the gene responsible for Huntington disease (HD) have stood witness to profound discoveries about the nature of the disease and its pathogenesis. Despite this progress, however, the development of disease-modifying therapies has thus far been slow. Preclinical validation of the therapeutic potential of disrupted pathways in HD has led to the advancement of pharmacological agents, both novel and repurposed, for clinical evaluation. The most promising therapeutic approaches include huntingtin (HTT) lowering and modification as well as modulation of neuroinflammation and synaptic transmission. With clinical trials for many of these approaches imminent or currently ongoing, the coming years are promising not only for HD but also for more prevalent neurodegenerative disorders, such as Alzheimer and Parkinson disease, in which many of these pathways have been similarly implicated.
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DeGuire SM, Ruggeri FS, Fares MB, Chiki A, Cendrowska U, Dietler G, Lashuel HA. N-terminal Huntingtin (Htt) phosphorylation is a molecular switch regulating Htt aggregation, helical conformation, internalization, and nuclear targeting. J Biol Chem 2018; 293:18540-18558. [PMID: 30185623 PMCID: PMC6290154 DOI: 10.1074/jbc.ra118.004621] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/25/2018] [Indexed: 12/31/2022] Open
Abstract
Huntington's disease is a fatal neurodegenerative disorder resulting from a CAG repeat expansion in the first exon of the gene encoding the Huntingtin protein (Htt). Phosphorylation of this protein region (Httex1) has been shown to play important roles in regulating the structure, toxicity, and cellular properties of N-terminal fragments and full-length Htt. However, increasing evidence suggests that phosphomimetic substitutions in Htt result in inconsistent findings and do not reproduce all aspects of true phosphorylation. Here, we investigated the effects of bona fide phosphorylation at Ser-13 or Ser-16 on the structure, aggregation, membrane binding, and subcellular properties of the Httex1-Q18A variant and compared these effects with those of phosphomimetic substitutions. We show that phosphorylation at either Ser-13 and/or Ser-16 or phosphomimetic substitutions at both these residues inhibit the aggregation of mutant Httex1, but that only phosphorylation strongly disrupts the amphipathic α-helix of the N terminus and prompts the internalization and nuclear targeting of preformed Httex1 aggregates. In synthetic peptides, phosphorylation at Ser-13, Ser-16, or both residues strongly disrupted the amphipathic α-helix of the N-terminal 17 residues (Nt17) of Httex1 and Nt17 membrane binding. Experiments with peptides bearing different combinations of phosphorylation sites within Nt17 revealed a phosphorylation-dependent switch that regulates the Httex1 structure, involving cross-talk between phosphorylation at Thr-3 and Ser-13 or Ser-16. Our results provide crucial insights into the role of phosphorylation in regulating Httex1 structure and function, and underscore the critical importance of identifying the enzymes responsible for regulating Htt phosphorylation, and their potential as therapeutic targets for managing Huntington's disease.
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Affiliation(s)
- Sean M DeGuire
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
| | - Francesco S Ruggeri
- the Laboratory of the Physics of Living Matter, Institute of Physics of Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Mohamed-Bilal Fares
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
| | - Anass Chiki
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
| | - Urszula Cendrowska
- the Laboratory of the Physics of Living Matter, Institute of Physics of Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Giovanni Dietler
- the Laboratory of the Physics of Living Matter, Institute of Physics of Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
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N6-Furfuryladenine is protective in Huntington's disease models by signaling huntingtin phosphorylation. Proc Natl Acad Sci U S A 2018; 115:E7081-E7090. [PMID: 29987005 DOI: 10.1073/pnas.1801772115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The huntingtin N17 domain is a modulator of mutant huntingtin toxicity and is hypophosphorylated in Huntington's disease (HD). We conducted high-content analysis to find compounds that could restore N17 phosphorylation. One lead compound from this screen was N6-furfuryladenine (N6FFA). N6FFA was protective in HD model neurons, and N6FFA treatment of an HD mouse model corrects HD phenotypes and eliminates cortical mutant huntingtin inclusions. We show that N6FFA restores N17 phosphorylation levels by being salvaged to a triphosphate form by adenine phosphoribosyltransferase (APRT) and used as a phosphate donor by casein kinase 2 (CK2). N6FFA is a naturally occurring product of oxidative DNA damage. Phosphorylated huntingtin functionally redistributes and colocalizes with CK2, APRT, and N6FFA DNA adducts at sites of induced DNA damage. We present a model in which this natural product compound is salvaged to provide a triphosphate substrate to signal huntingtin phosphorylation via CK2 during low-ATP stress under conditions of DNA damage, with protective effects in HD model systems.
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48
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Caterino M, Squillaro T, Montesarchio D, Giordano A, Giancola C, Melone MAB. Huntingtin protein: A new option for fixing the Huntington's disease countdown clock. Neuropharmacology 2018. [PMID: 29526547 DOI: 10.1016/j.neuropharm.2018.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Huntington's disease is a dreadful, incurable disorder. It springs from the autosomal dominant mutation in the first exon of the HTT gene, which encodes for the huntingtin protein (HTT) and results in progressive neurodegeneration. Thus far, all the attempted approaches to tackle the mutant HTT-induced toxicity causing this disease have failed. The mutant protein comes with the aberrantly expanded poly-glutamine tract. It is primarily to blame for the build-up of β-amyloid-like HTT aggregates, deleterious once broadened beyond the critical ∼35-37 repeats threshold. Recent experimental findings have provided valuable information on the molecular basis underlying this HTT-driven neurodegeneration. These findings indicate that the poly-glutamine siding regions and many post-translation modifications either abet or counter the poly-glutamine tract. This review provides an overall, up-to-date insight into HTT biophysics and structural biology, particularly discussing novel pharmacological options to specifically target the mutated protein and thus inhibit its functions and toxicity.
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Affiliation(s)
- Marco Caterino
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy
| | - Tiziana Squillaro
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Daniela Montesarchio
- InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA; Department of Medicine, Surgery and Neuroscience University of Siena, Siena, Italy
| | - Concetta Giancola
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy.
| | - Mariarosa A B Melone
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.
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Karyopherin α-3 is a key protein in the pathogenesis of spinocerebellar ataxia type 3 controlling the nuclear localization of ataxin-3. Proc Natl Acad Sci U S A 2018; 115:E2624-E2633. [PMID: 29476013 DOI: 10.1073/pnas.1716071115] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disorder caused by a CAG expansion in the ATXN3 gene leading to a polyglutamine expansion in the ataxin-3 protein. The nuclear presence and aggregation of expanded ataxin-3 are critical steps in disease pathogenesis. To identify novel therapeutic targets, we investigated the nucleocytoplasmic transport system by screening a collection of importins and exportins that potentially modulate this nuclear localization. Using cell, Drosophila, and mouse models, we focused on three transport proteins, namely, CRM1, IPO13, KPNA3, and their respective Drosophila orthologs Emb, Cdm, and Kap-α3. While overexpression of CRM1/Emb demonstrated positive effects in Drosophila, KPNA3/Kap-α3 emerged as the most promising target, as knockdown via multiple RNAi lines demonstrated its ability to shuttle both truncated and full-length expanded ataxin-3, rescue neurodegeneration, restore photoreceptor formation, and reduce aggregation. Furthermore, KPNA3 knockout in SCA3 mice resulted in an amelioration of molecular and behavioral disturbances such as total activity, anxiety, and gait. Since KPNA3 is known to function as an import protein and recognize nuclear localization signals (NLSs), this work unites ataxin-3 structure to the nuclear pore machinery and provides a link between karyopherins, NLS signals, and polyglutamine disease, as well as demonstrates that KPNA3 is a key player in the pathogenesis of SCA3.
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50
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Phosphorylation of huntingtin at residue T3 is decreased in Huntington's disease and modulates mutant huntingtin protein conformation. Proc Natl Acad Sci U S A 2017; 114:E10809-E10818. [PMID: 29162692 PMCID: PMC5740681 DOI: 10.1073/pnas.1705372114] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Posttranslational modifications can have profound effects on the biological and biophysical properties of proteins associated with misfolding and aggregation. However, their detection and quantification in clinical samples and an understanding of the mechanisms underlying the pathological properties of misfolding- and aggregation-prone proteins remain a challenge for diagnostics and therapeutics development. We have applied an ultrasensitive immunoassay platform to develop and validate a quantitative assay for detecting a posttranslational modification (phosphorylation at residue T3) of a protein associated with polyglutamine repeat expansion, namely Huntingtin, and characterized its presence in a variety of preclinical and clinical samples. We find that T3 phosphorylation is greatly reduced in samples from Huntington's disease models and in Huntington's disease patients, and we provide evidence that bona-fide T3 phosphorylation alters Huntingtin exon 1 protein conformation and aggregation properties. These findings have significant implications for both mechanisms of disease pathogenesis and the development of therapeutics and diagnostics for Huntington's disease.
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