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Sultana OF, Bandaru M, Islam MA, Reddy PH. Unraveling the complexity of human brain: Structure, function in healthy and disease states. Ageing Res Rev 2024; 100:102414. [PMID: 39002647 DOI: 10.1016/j.arr.2024.102414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 06/29/2024] [Accepted: 07/05/2024] [Indexed: 07/15/2024]
Abstract
The human brain stands as an intricate organ, embodying a nexus of structure, function, development, and diversity. This review delves into the multifaceted landscape of the brain, spanning its anatomical intricacies, diverse functional capacities, dynamic developmental trajectories, and inherent variability across individuals. The dynamic process of brain development, from early embryonic stages to adulthood, highlights the nuanced changes that occur throughout the lifespan. The brain, a remarkably complex organ, is composed of various anatomical regions, each contributing uniquely to its overall functionality. Through an exploration of neuroanatomy, neurophysiology, and electrophysiology, this review elucidates how different brain structures interact to support a wide array of cognitive processes, sensory perception, motor control, and emotional regulation. Moreover, it addresses the impact of age, sex, and ethnic background on brain structure and function, and gender differences profoundly influence the onset, progression, and manifestation of brain disorders shaped by genetic, hormonal, environmental, and social factors. Delving into the complexities of the human brain, it investigates how variations in anatomical configuration correspond to diverse functional capacities across individuals. Furthermore, it examines the impact of neurodegenerative diseases on the structural and functional integrity of the brain. Specifically, our article explores the pathological processes underlying neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases, shedding light on the structural alterations and functional impairments that accompany these conditions. We will also explore the current research trends in neurodegenerative diseases and identify the existing gaps in the literature. Overall, this article deepens our understanding of the fundamental principles governing brain structure and function and paves the way for a deeper understanding of individual differences and tailored approaches in neuroscience and clinical practice-additionally, a comprehensive understanding of structural and functional changes that manifest in neurodegenerative diseases.
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Affiliation(s)
- Omme Fatema Sultana
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Madhuri Bandaru
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Md Ariful Islam
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Nutritional Sciences Department, College of Human Sciences, Texas Tech University, Lubbock, TX 79409, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA 5. Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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2
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Bonanni R, Cariati I, Cifelli P, Frank C, Annino G, Tancredi V, D'Arcangelo G. Exercise to Counteract Alzheimer's Disease: What Do Fluid Biomarkers Say? Int J Mol Sci 2024; 25:6951. [PMID: 39000060 PMCID: PMC11241657 DOI: 10.3390/ijms25136951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/14/2024] [Accepted: 06/22/2024] [Indexed: 07/16/2024] Open
Abstract
Neurodegenerative diseases (NDs) represent an unsolved problem to date with an ever-increasing population incidence. Particularly, Alzheimer's disease (AD) is the most widespread ND characterized by an accumulation of amyloid aggregates of beta-amyloid (Aβ) and Tau proteins that lead to neuronal death and subsequent cognitive decline. Although neuroimaging techniques are needed to diagnose AD, the investigation of biomarkers within body fluids could provide important information on neurodegeneration. Indeed, as there is no definitive solution for AD, the monitoring of these biomarkers is of strategic importance as they are useful for both diagnosing AD and assessing the progression of the neurodegenerative state. In this context, exercise is known to be an effective non-pharmacological management strategy for AD that can counteract cognitive decline and neurodegeneration. However, investigation of the concentration of fluid biomarkers in AD patients undergoing exercise protocols has led to unclear and often conflicting results, suggesting the need to clarify the role of exercise in modulating fluid biomarkers in AD. Therefore, this critical literature review aims to gather evidence on the main fluid biomarkers of AD and the modulatory effects of exercise to clarify the efficacy and usefulness of this non-pharmacological strategy in counteracting neurodegeneration in AD.
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Affiliation(s)
- Roberto Bonanni
- Department of Biomedicine and Prevention, "Tor Vergata" University of Rome, 00133 Rome, Italy
| | - Ida Cariati
- Department of Systems Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
| | - Pierangelo Cifelli
- Department of Applied Clinical and Biotechnological Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Claudio Frank
- UniCamillus-Saint Camillus International University of Health Sciences, 00131 Rome, Italy
| | - Giuseppe Annino
- Department of Systems Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
- Centre of Space Bio-Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
- Sports Engineering Laboratory, Department of Industrial Engineering, "Tor Vergata" University of Rome, 00133 Rome, Italy
| | - Virginia Tancredi
- Department of Systems Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
- Centre of Space Bio-Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
| | - Giovanna D'Arcangelo
- Department of Systems Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
- Centre of Space Bio-Medicine, "Tor Vergata" University of Rome, 00133 Rome, Italy
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3
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Bonsor M, Ammar O, Schnoegl S, Wanker EE, Silva Ramos E. Polyglutamine disease proteins: Commonalities and differences in interaction profiles and pathological effects. Proteomics 2024; 24:e2300114. [PMID: 38615323 DOI: 10.1002/pmic.202300114] [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: 11/30/2023] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/16/2024]
Abstract
Currently, nine polyglutamine (polyQ) expansion diseases are known. They include spinocerebellar ataxias (SCA1, 2, 3, 6, 7, 17), spinal and bulbar muscular atrophy (SBMA), dentatorubral-pallidoluysian atrophy (DRPLA), and Huntington's disease (HD). At the root of these neurodegenerative diseases are trinucleotide repeat mutations in coding regions of different genes, which lead to the production of proteins with elongated polyQ tracts. While the causative proteins differ in structure and molecular mass, the expanded polyQ domains drive pathogenesis in all these diseases. PolyQ tracts mediate the association of proteins leading to the formation of protein complexes involved in gene expression regulation, RNA processing, membrane trafficking, and signal transduction. In this review, we discuss commonalities and differences among the nine polyQ proteins focusing on their structure and function as well as the pathological features of the respective diseases. We present insights from AlphaFold-predicted structural models and discuss the biological roles of polyQ-containing proteins. Lastly, we explore reported protein-protein interaction networks to highlight shared protein interactions and their potential relevance in disease development.
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Affiliation(s)
- Megan Bonsor
- Department of Neuroproteomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Orchid Ammar
- Department of Neuroproteomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Sigrid Schnoegl
- Department of Neuroproteomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Erich E Wanker
- Department of Neuroproteomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Eduardo Silva Ramos
- Department of Neuroproteomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
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4
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Duda-Madej A, Stecko J, Szymańska N, Miętkiewicz A, Szandruk-Bender M. Amyloid, Crohn's disease, and Alzheimer's disease - are they linked? Front Cell Infect Microbiol 2024; 14:1393809. [PMID: 38779559 PMCID: PMC11109451 DOI: 10.3389/fcimb.2024.1393809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
Crohn's disease (CD) is a chronic inflammatory disease that most frequently affects part of the distal ileum, but it may affect any part of the gastrointestinal tract. CD may also be related to systemic inflammation and extraintestinal manifestations. Alzheimer's disease (AD) is the most common neurodegenerative disease, gradually worsening behavioral and cognitive functions. Despite the meaningful progress, both diseases are still incurable and have a not fully explained, heterogeneous pathomechanism that includes immunological, microbiological, genetic, and environmental factors. Recently, emerging evidence indicates that chronic inflammatory condition corresponds to an increased risk of neurodegenerative diseases, and intestinal inflammation, including CD, increases the risk of AD. Even though it is now known that CD increases the risk of AD, the exact pathways connecting these two seemingly unrelated diseases remain still unclear. One of the key postulates is the gut-brain axis. There is increasing evidence that the gut microbiota with its proteins, DNA, and metabolites influence several processes related to the etiology of AD, including β-amyloid abnormality, Tau phosphorylation, and neuroinflammation. Considering the role of microbiota in both CD and AD pathology, in this review, we want to shed light on bacterial amyloids and their potential to influence cerebral amyloid aggregation and neuroinflammation and provide an overview of the current literature on amyloids as a potential linker between AD and CD.
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Affiliation(s)
- Anna Duda-Madej
- Department of Microbiology, Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | - Jakub Stecko
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | | | | | - Marta Szandruk-Bender
- Department of Pharmacology, Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
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5
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Mohanty P, Phan TM, Mittal J. Transient interdomain interactions modulate the monomeric structural ensemble and oligomerization landscape of Huntingtin Exon 1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592468. [PMID: 38766024 PMCID: PMC11100600 DOI: 10.1101/2024.05.03.592468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Polyglutamine expansion (≥ 36 residues) within the N-terminal exon-1 of Huntingtin (Httex1) leads to Huntington's disease, a neurogenerative condition marked by the presence of intranuclear Htt inclusions. Notably, the polyglutamine tract in Httex1 is flanked by an N-terminal coiled-coil domain - N17 (17 amino acids), which undergoes self-association to promote the formation of soluble Httex1 oligomers and brings the aggregation-prone polyQ tracts in close spatial proximity. However, the mechanisms underlying the subsequent conversion of soluble oligomers into insoluble β-rich aggregates with increasing polyQ length, remain unclear. Current knowledge suggests that expansion of the polyQ tract increases its helicity, and this favors its oligomerization and aggregation. In addition, studies utilizing conformation-specific antibodies and a stable coiled-coil heterotetrametric system fused to polyQ indicate that domain "cross-talk" (i.e., interdomain interactions) may be necessary to efficiently promote the emergence of toxic conformations (in monomers and oligomers) and fibrillar aggregation. Here, we performed extensive atomistic molecular dynamics (MD) simulations (aggregate time ∼ 0.7 ms) of N17-polyQ fragments to uncover the interplay between structural transformation and domain "cross-talk" on the monomeric structural ensemble and oligomerization landscape of Httex1. Our simulation ensembles of N17-polyQ monomers validated against 13 C NMR chemical shifts indicated that in addition to elevated α-helicity, polyQ expansion also favors transient, interdomain (N17-polyQ) interactions which result in the emergence of β-conformations. Further, interdomain interactions decreased the overall stability of N17-mediated dimers by counteracting the stabilizing effect of increased α-helicity and promoted a heterogenous oligomerization landscape on the sub-microsecond timescale. Overall, our study uncovers the significance of domain "cross-talk" in modulating the monomeric conformational ensemble and oligomerization landscape of Httex1 to favor the formation of amyloid aggregates.
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6
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Liu Y, Zhang B, Duan R, Liu Y. Mitochondrial DNA Leakage and cGas/STING Pathway in Microglia: Crosstalk Between Neuroinflammation and Neurodegeneration. Neuroscience 2024; 548:1-8. [PMID: 38685462 DOI: 10.1016/j.neuroscience.2024.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/04/2024] [Accepted: 04/24/2024] [Indexed: 05/02/2024]
Abstract
Neurodegenerative diseases, characterized by abnormal deposition of misfolded proteins, often present with progressive loss of neurons. Chronic neuroinflammation is a striking hallmark of neurodegeneration. Microglia, as the primary immune cells in the brain, is the main type of cells that participate in the formation of inflammatory microenvironment. Cytoplasmic free mitochondrial DNA (mtDNA), a common component of damage-associated molecular patterns (DAMPs), can activate the cGas/stimulator of interferon genes (STING) signalling, which subsequently produces type I interferon and proinflammatory cytokines. There are various sources of free mtDNA in microglial cytoplasm, but mitochondrial oxidative stress accumulation plays the vital role. The upregulation of cGas/STING pathway in microglia contributes to the abnormal and persistent microglial activation, accompanied by excessive secretion of neurotoxic inflammatory mediators such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), which exacerbates the damage of neurons and promotes the development of neurodegeneration. Currently, novel therapeutic approaches need to be found to delay the progression of neurodegenerative disorders, and regulation of the cGas/STING signaling in microglia may be a potential target.
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Affiliation(s)
- Yuqian Liu
- Qilu Hospital of Shandong University, Jinan, China
| | - Bohan Zhang
- Qilu Hospital of Shandong University, Jinan, China
| | - Ruonan Duan
- Qilu Hospital of Shandong University, Jinan, China.
| | - Yiming Liu
- Qilu Hospital of Shandong University, Jinan, China.
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7
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van der Wel PC. Solid-state nuclear magnetic resonance in the structural study of polyglutamine aggregation. Biochem Soc Trans 2024; 52:719-731. [PMID: 38563485 PMCID: PMC11088915 DOI: 10.1042/bst20230731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/06/2024] [Accepted: 03/19/2024] [Indexed: 04/04/2024]
Abstract
The aggregation of proteins into amyloid-like fibrils is seen in many neurodegenerative diseases. Recent years have seen much progress in our understanding of these misfolded protein inclusions, thanks to advances in techniques such as solid-state nuclear magnetic resonance (ssNMR) spectroscopy and cryogenic electron microscopy (cryo-EM). However, multiple repeat-expansion-related disorders have presented special challenges to structural elucidation. This review discusses the special role of ssNMR analysis in the study of protein aggregates associated with CAG repeat expansion disorders. In these diseases, the misfolding and aggregation affect mutant proteins with expanded polyglutamine segments. The most common disorder, Huntington's disease (HD), is connected to the mutation of the huntingtin protein. Since the discovery of the genetic causes for HD in the 1990s, steady progress in our understanding of the role of protein aggregation has depended on the integrative and interdisciplinary use of multiple types of structural techniques. The heterogeneous and dynamic features of polyQ protein fibrils, and in particular those formed by huntingtin N-terminal fragments, have made these aggregates into challenging targets for structural analysis. ssNMR has offered unique insights into many aspects of these amyloid-like aggregates. These include the atomic-level structure of the polyglutamine core, but also measurements of dynamics and solvent accessibility of the non-core flanking domains of these fibrils' fuzzy coats. The obtained structural insights shed new light on pathogenic mechanisms behind this and other protein misfolding diseases.
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8
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Henriques C, Lopes MM, Silva AC, Lobo DD, Badin RA, Hantraye P, Pereira de Almeida L, Nobre RJ. Viral-based animal models in polyglutamine disorders. Brain 2024; 147:1166-1189. [PMID: 38284949 DOI: 10.1093/brain/awae012] [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: 07/09/2023] [Revised: 11/26/2023] [Accepted: 12/30/2023] [Indexed: 01/30/2024] Open
Abstract
Polyglutamine disorders are a complex group of incurable neurodegenerative disorders caused by an abnormal expansion in the trinucleotide cytosine-adenine-guanine tract of the affected gene. To better understand these disorders, our dependence on animal models persists, primarily relying on transgenic models. In an effort to complement and deepen our knowledge, researchers have also developed animal models of polyglutamine disorders employing viral vectors. Viral vectors have been extensively used to deliver genes to the brain, not only for therapeutic purposes but also for the development of animal models, given their remarkable flexibility. In a time- and cost-effective manner, it is possible to use different transgenes, at varying doses, in diverse targeted tissues, at different ages, and in different species, to recreate polyglutamine pathology. This paper aims to showcase the utility of viral vectors in disease modelling, share essential considerations for developing animal models with viral vectors, and provide a comprehensive review of existing viral-based animal models for polyglutamine disorders.
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Affiliation(s)
- Carina Henriques
- Center for Neuroscience and Cell Biology (CNC), Gene and Stem Cell Therapies for the Brain Group, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), Vectors, Gene and Cell Therapy Group, University of Coimbra, 3004-504 Coimbra, Portugal
- ViraVector-Viral Vector for Gene Transfer Core Facility, University of Coimbra, 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Miguel M Lopes
- Center for Neuroscience and Cell Biology (CNC), Gene and Stem Cell Therapies for the Brain Group, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), Vectors, Gene and Cell Therapy Group, University of Coimbra, 3004-504 Coimbra, Portugal
- ViraVector-Viral Vector for Gene Transfer Core Facility, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research (III), University of Coimbra, 3030-789 Coimbra, Portugal
| | - Ana C Silva
- Center for Neuroscience and Cell Biology (CNC), Gene and Stem Cell Therapies for the Brain Group, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), Vectors, Gene and Cell Therapy Group, University of Coimbra, 3004-504 Coimbra, Portugal
- ViraVector-Viral Vector for Gene Transfer Core Facility, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research (III), University of Coimbra, 3030-789 Coimbra, Portugal
| | - Diana D Lobo
- Center for Neuroscience and Cell Biology (CNC), Gene and Stem Cell Therapies for the Brain Group, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), Vectors, Gene and Cell Therapy Group, University of Coimbra, 3004-504 Coimbra, Portugal
- ViraVector-Viral Vector for Gene Transfer Core Facility, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research (III), University of Coimbra, 3030-789 Coimbra, Portugal
| | - Romina Aron Badin
- CEA, DRF, Institute of Biology François Jacob, Molecular Imaging Research Center (MIRCen), 92265 Fontenay-aux-Roses, France
- CNRS, CEA, Paris-Sud University, Université Paris-Saclay, Neurodegenerative Diseases Laboratory (UMR9199), 92265 Fontenay-aux-Roses, France
| | - Philippe Hantraye
- CEA, DRF, Institute of Biology François Jacob, Molecular Imaging Research Center (MIRCen), 92265 Fontenay-aux-Roses, France
- CNRS, CEA, Paris-Sud University, Université Paris-Saclay, Neurodegenerative Diseases Laboratory (UMR9199), 92265 Fontenay-aux-Roses, France
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology (CNC), Gene and Stem Cell Therapies for the Brain Group, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), Vectors, Gene and Cell Therapy Group, University of Coimbra, 3004-504 Coimbra, Portugal
- ViraVector-Viral Vector for Gene Transfer Core Facility, University of Coimbra, 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Rui Jorge Nobre
- Center for Neuroscience and Cell Biology (CNC), Gene and Stem Cell Therapies for the Brain Group, University of Coimbra, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), Vectors, Gene and Cell Therapy Group, University of Coimbra, 3004-504 Coimbra, Portugal
- ViraVector-Viral Vector for Gene Transfer Core Facility, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research (III), University of Coimbra, 3030-789 Coimbra, Portugal
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Skeens A, Siriwardhana C, Massinople SE, Wunder MM, Ellis ZL, Keith KM, Girman T, Frey SL, Legleiter J. The polyglutamine domain is the primary driver of seeding in huntingtin aggregation. PLoS One 2024; 19:e0298323. [PMID: 38483973 PMCID: PMC10939245 DOI: 10.1371/journal.pone.0298323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 01/22/2024] [Indexed: 03/17/2024] Open
Abstract
Huntington's Disease (HD) is a fatal, neurodegenerative disease caused by aggregation of the huntingtin protein (htt) with an expanded polyglutamine (polyQ) domain into amyloid fibrils. Htt aggregation is modified by flanking sequences surrounding the polyQ domain as well as the binding of htt to lipid membranes. Upon fibrillization, htt fibrils are able to template the aggregation of monomers into fibrils in a phenomenon known as seeding, and this process appears to play a critical role in cell-to-cell spread of HD. Here, exposure of C. elegans expressing a nonpathogenic N-terminal htt fragment (15-repeat glutamine residues) to preformed htt-exon1 fibrils induced inclusion formation and resulted in decreased viability in a dose dependent manner, demonstrating that seeding can induce toxic aggregation of nonpathogenic forms of htt. To better understand this seeding process, the impact of flanking sequences adjacent to the polyQ stretch, polyQ length, and the presence of model lipid membranes on htt seeding was investigated. Htt seeding readily occurred across polyQ lengths and was independent of flanking sequence, suggesting that the structured polyQ domain within fibrils is the key contributor to the seeding phenomenon. However, the addition of lipid vesicles modified seeding efficiency in a manner suggesting that seeding primarily occurs in bulk solution and not at the membrane interface. In addition, fibrils formed in the presence of lipid membranes displayed similar seeding efficiencies. Collectively, this suggests that the polyQ domain that forms the amyloid fibril core is the main driver of seeding in htt aggregation.
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Affiliation(s)
- Adam Skeens
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Chathuranga Siriwardhana
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Sophia E. Massinople
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Michelle M. Wunder
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Zachary L. Ellis
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Kaitlyn M. Keith
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Tyler Girman
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Shelli L. Frey
- The Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania, United States of America
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
- Rockefeller Neurosciences Institutes, West Virginia University, Morgantown, West Virginia, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia, United States of America
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10
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Parlato R, Volarić J, Lasorsa A, Bagherpoor Helabad M, Kobauri P, Jain G, Miettinen MS, Feringa BL, Szymanski W, van der Wel PCA. Photocontrol of the β-Hairpin Polypeptide Structure through an Optimized Azobenzene-Based Amino Acid Analogue. J Am Chem Soc 2024; 146:2062-2071. [PMID: 38226790 PMCID: PMC10811659 DOI: 10.1021/jacs.3c11155] [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: 10/09/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/17/2024]
Abstract
A family of neurodegenerative diseases, including Huntington's disease (HD) and spinocerebellar ataxias, are associated with an abnormal polyglutamine (polyQ) expansion in mutant proteins that become prone to form amyloid-like aggregates. Prior studies have suggested a key role for β-hairpin formation as a driver of nucleation and aggregation, but direct experimental studies have been challenging. Toward such research, we set out to enable spatiotemporal control over β-hairpin formation by the introduction of a photosensitive β-turn mimic in the polypeptide backbone, consisting of a newly designed azobenzene derivative. The reported derivative overcomes the limitations of prior approaches associated with poor photochemical properties and imperfect structural compatibility with the desired β-turn structure. A new azobenzene-based β-turn mimic was designed, synthesized, and found to display improved photochemical properties, both prior and after incorporation into the backbone of a polyQ polypeptide. The two isomers of the azobenzene-polyQ peptide showed different aggregate structures of the polyQ peptide fibrils, as demonstrated by electron microscopy and solid-state NMR (ssNMR). Notably, only peptides in which the β-turn structure was stabilized (azobenzene in the cis configuration) closely reproduced the spectral fingerprints of toxic, β-hairpin-containing fibrils formed by mutant huntingtin protein fragments implicated in HD. These approaches and findings will enable better deciphering of the roles of β-hairpin structures in protein aggregation processes in HD and other amyloid-related neurodegenerative diseases.
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Affiliation(s)
- Raffaella Parlato
- Zernike
Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Jana Volarić
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747
AG Groningen, The
Netherlands
| | - Alessia Lasorsa
- Zernike
Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Mahdi Bagherpoor Helabad
- Department
of Theory and Bio-Systems, Max Planck Institute
of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Piermichele Kobauri
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747
AG Groningen, The
Netherlands
| | - Greeshma Jain
- Zernike
Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Markus S. Miettinen
- Computational
Biology Unit, Departments of Chemistry and Informatics, University of Bergen, 5020 Bergen, Norway
| | - Ben L. Feringa
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747
AG Groningen, The
Netherlands
| | - Wiktor Szymanski
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747
AG Groningen, The
Netherlands
- Medical
Imaging Center, University Medical Center
Groningen, Hanzeplein
1, 9713 GZ Groningen, The Netherlands
| | - Patrick C. A. van der Wel
- Zernike
Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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11
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Kandola T, Venkatesan S, Zhang J, Lerbakken BT, Von Schulze A, Blanck JF, Wu J, Unruh JR, Berry P, Lange JJ, Box AC, Cook M, Sagui C, Halfmann R. Pathologic polyglutamine aggregation begins with a self-poisoning polymer crystal. eLife 2023; 12:RP86939. [PMID: 37921648 PMCID: PMC10624427 DOI: 10.7554/elife.86939] [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] [Indexed: 11/04/2023] Open
Abstract
A long-standing goal of amyloid research has been to characterize the structural basis of the rate-determining nucleating event. However, the ephemeral nature of nucleation has made this goal unachievable with existing biochemistry, structural biology, and computational approaches. Here, we addressed that limitation for polyglutamine (polyQ), a polypeptide sequence that causes Huntington's and other amyloid-associated neurodegenerative diseases when its length exceeds a characteristic threshold. To identify essential features of the polyQ amyloid nucleus, we used a direct intracellular reporter of self-association to quantify frequencies of amyloid appearance as a function of concentration, conformational templates, and rational polyQ sequence permutations. We found that nucleation of pathologically expanded polyQ involves segments of three glutamine (Q) residues at every other position. We demonstrate using molecular simulations that this pattern encodes a four-stranded steric zipper with interdigitated Q side chains. Once formed, the zipper poisoned its own growth by engaging naive polypeptides on orthogonal faces, in a fashion characteristic of polymer crystals with intramolecular nuclei. We further show that self-poisoning can be exploited to block amyloid formation, by genetically oligomerizing polyQ prior to nucleation. By uncovering the physical nature of the rate-limiting event for polyQ aggregation in cells, our findings elucidate the molecular etiology of polyQ diseases.
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Affiliation(s)
- Tej Kandola
- Stowers Institute for Medical ResearchKansas CityUnited States
- The Open UniversityMilton KeynesUnited Kingdom
| | | | - Jiahui Zhang
- Department of Physics, North Carolina State UniversityRaleighUnited States
| | | | | | | | - Jianzheng Wu
- Stowers Institute for Medical ResearchKansas CityUnited States
- Department of Biochemistry and Molecular Biology, University of Kansas Medical CenterKansas CityUnited States
| | - Jay R Unruh
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Paula Berry
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Jeffrey J Lange
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Andrew C Box
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Malcolm Cook
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Celeste Sagui
- Department of Physics, North Carolina State UniversityRaleighUnited States
| | - Randal Halfmann
- Stowers Institute for Medical ResearchKansas CityUnited States
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12
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Kandola T, Venkatesan S, Zhang J, Lerbakken B, Schulze AV, Blanck JF, Wu J, Unruh J, Berry P, Lange JJ, Box A, Cook M, Sagui C, Halfmann R. Pathologic polyglutamine aggregation begins with a self-poisoning polymer crystal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533418. [PMID: 36993401 PMCID: PMC10055281 DOI: 10.1101/2023.03.20.533418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
A long-standing goal of amyloid research has been to characterize the structural basis of the rate-determining nucleating event. However, the ephemeral nature of nucleation has made this goal unachievable with existing biochemistry, structural biology, and computational approaches. Here, we addressed that limitation for polyglutamine (polyQ), a polypeptide sequence that causes Huntington's and other amyloid-associated neurodegenerative diseases when its length exceeds a characteristic threshold. To identify essential features of the polyQ amyloid nucleus, we used a direct intracellular reporter of self-association to quantify frequencies of amyloid appearance as a function of concentration, conformational templates, and rational polyQ sequence permutations. We found that nucleation of pathologically expanded polyQ involves segments of three glutamine (Q) residues at every other position. We demonstrate using molecular simulations that this pattern encodes a four-stranded steric zipper with interdigitated Q side chains. Once formed, the zipper poisoned its own growth by engaging naive polypeptides on orthogonal faces, in a fashion characteristic of polymer crystals with intramolecular nuclei. We further show that self-poisoning can be exploited to block amyloid formation, by genetically oligomerizing polyQ prior to nucleation. By uncovering the physical nature of the rate-limiting event for polyQ aggregation in cells, our findings elucidate the molecular etiology of polyQ diseases.
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Affiliation(s)
- Tej Kandola
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- The Open University, Milton Keyes, MK7 6AA, UK
| | | | - Jiahui Zhang
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | | | - Alex Von Schulze
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jillian F Blanck
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jianzheng Wu
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jay Unruh
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Paula Berry
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Jeffrey J Lange
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Andrew Box
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Malcolm Cook
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Celeste Sagui
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Randal Halfmann
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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13
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Helabad MB, Matlahov I, Daldrop JO, Jain G, van der Wel PC, Miettinen MS. Integrative determination of the atomic structure of mutant huntingtin exon 1 fibrils from Huntington's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.549993. [PMID: 37502911 PMCID: PMC10370190 DOI: 10.1101/2023.07.21.549993] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Neurodegeneration in Huntington's disease (HD) is accompanied by the aggregation of fragments of the mutant huntingtin protein, a biomarker of disease progression. A particular pathogenic role has been attributed to the aggregation-prone huntingtin exon 1 (HttEx1) fragment, whose polyglutamine (polyQ) segment is expanded. Unlike amyloid fibrils from Parkinson's and Alzheimer's diseases, the atomic-level structure of HttEx1 fibrils has remained unknown, limiting diagnostic and treatment efforts. We present and analyze the structure of fibrils formed by polyQ peptides and polyQ-expanded HttEx1. Atomic-resolution perspectives are enabled by an integrative analysis and unrestrained all-atom molecular dynamics (MD) simulations incorporating experimental data from electron microscopy (EM), solid-state NMR, and other techniques. Visualizing the HttEx1 subdomains in atomic detail helps explaining the biological properties of these protein aggregates, as well as paves the way for targeting them for detection and degradation.
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Affiliation(s)
- Mahdi Bagherpoor Helabad
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
- Institute for Drug Discovery, Leipzig University Medical Center, 04103 Leipzig, Germany
| | - Irina Matlahov
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Jan O. Daldrop
- Fachbereich Physik, Freie Universitä t Berlin, 14195 Berlin, Germany
| | - Greeshma Jain
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | | | - Markus S. Miettinen
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
- Fachbereich Physik, Freie Universitä t Berlin, 14195 Berlin, Germany
- Department of Chemistry, University of Bergen, 5007 Bergen, Norway
- Computational Biology Unit, Department of Informatics, University of Bergen, 5008 Bergen, Norway
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14
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Tsai TY, Chen CY, Lin TW, Lin TC, Chiu FL, Shih O, Chang MY, Lin YC, Su AC, Chen CM, Jeng US, Kuo HC, Chang CF, Chen YR. Amyloid modifier SERF1a interacts with polyQ-expanded huntingtin-exon 1 via helical interactions and exacerbates polyQ-induced toxicity. Commun Biol 2023; 6:767. [PMID: 37479809 PMCID: PMC10361993 DOI: 10.1038/s42003-023-05142-0] [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: 01/05/2023] [Accepted: 07/13/2023] [Indexed: 07/23/2023] Open
Abstract
Abnormal polyglutamine (polyQ) expansion and fibrillization occur in Huntington's disease (HD). Amyloid modifier SERF enhances amyloid formation, but the underlying mechanism is not revealed. Here, the fibrillization and toxicity effect of SERF1a on Htt-exon1 are examined. SERF1a enhances the fibrillization of and interacts with mutant thioredoxin (Trx)-fused Httex1. NMR studies with Htt peptides show that TrxHttex1-39Q interacts with the helical regions in SERF1a and SERF1a preferentially interacts with the N-terminal 17 residues of Htt. Time-course analysis shows that SERF1a induces mutant TrxHttex1 to a single conformation enriched of β-sheet. Co-expression of SERF1a and Httex1-polyQ in neuroblastoma and lentiviral infection of SERF1a in HD-induced polypotent stem cell (iPSC)-derived neurons demonstrates the detrimental effect of SERF1a in HD. Higher level of SERF1a transcript or protein is detected in HD iPSC, transgenic mice, and HD plasma. Overall, this study provides molecular mechanism for SERF1a and mutant Httex1 to facilitate therapeutic development for HD.
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Affiliation(s)
- Tien-Ying Tsai
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Biological Chemistry, Academia Sinica, 128, Academia Road, Sec. 2. Nankang, Taipei, 115, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Chun-Yu Chen
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
| | - Tien-Wei Lin
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
| | - Tien-Chang Lin
- National Synchrotron Radiation Research Center, Hsinchu, 300, Taiwan
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Feng-Lan Chiu
- Institute of Cellular and Organismic Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
| | - Orion Shih
- National Synchrotron Radiation Research Center, Hsinchu, 300, Taiwan
| | - Ming-Yun Chang
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
| | - Yu-Chun Lin
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
| | - An-Chung Su
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Chiung-Mei Chen
- Department of Neurology, Linkou Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center, Hsinchu, 300, Taiwan
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Hung-Chih Kuo
- Institute of Cellular and Organismic Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
| | - Chi-Fon Chang
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan
| | - Yun-Ru Chen
- Genomics Research Center, Academia Sinica, 128, Academia Rd., Sec. 2, Nankang District, Taipei, 115, Taiwan.
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15
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Smith AN, Harrabi R, Halbritter T, Lee D, Aussenac F, van der Wel PCA, Hediger S, Sigurdsson ST, De Paëpe G. Fast magic angle spinning for the characterization of milligram quantities of organic and biological solids at natural isotopic abundance by 13C- 13C correlation DNP-enhanced NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2023; 123:101850. [PMID: 36592488 DOI: 10.1016/j.ssnmr.2022.101850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/25/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
We show that multidimensional solid-state NMR 13C-13C correlation spectra of biomolecular assemblies and microcrystalline organic molecules can be acquired at natural isotopic abundance with only milligram quantities of sample. These experiments combine fast Magic Angle Spinning of the sample, low-power dipolar recoupling, and dynamic nuclear polarization performed with AsymPol biradicals, a recently introduced family of polarizing agents. Such experiments are essential for structural characterization as they provide short- and long-range distance information. This approach is demonstrated on diverse sample types, including polyglutamine fibrils implicated in Huntington's disease and microcrystalline ampicillin, a small antibiotic molecule.
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Affiliation(s)
- Adam N Smith
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, MEM, 38000, Grenoble, France
| | - Rania Harrabi
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, MEM, 38000, Grenoble, France
| | - Thomas Halbritter
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107, Reykjavik, Iceland
| | - Daniel Lee
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, MEM, 38000, Grenoble, France
| | | | - Patrick C A van der Wel
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - Sabine Hediger
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, MEM, 38000, Grenoble, France
| | - Snorri Th Sigurdsson
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107, Reykjavik, Iceland
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, MEM, 38000, Grenoble, France.
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16
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Matlahov I, Boatz JC, C.A. van der Wel P. Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils. J Struct Biol X 2022; 6:100077. [PMID: 36419510 PMCID: PMC9677204 DOI: 10.1016/j.yjsbx.2022.100077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/20/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022] Open
Abstract
Mutant huntingtin exon 1 fibrils feature a broad range of molecular dynamics. Molecular motion is coupled to water dynamics outside the fiber core. Dynamics-based spectral editing ssNMR reveals mobile non-core residues. Intermediate-motion selection via dipolar dephasing of rigid sites. Semi-mobile glutamines outside the fiber core observed and identified.
Many amyloid-forming proteins, which are normally intrinsically disordered, undergo a disorder-to-order transition to form fibrils with a rigid β-sheet core flanked by disordered domains. Solid-state NMR (ssNMR) and cryogenic electron microscopy (cryoEM) excel at resolving the rigid structures within amyloid cores but studying the dynamically disordered domains remains challenging. This challenge is exemplified by mutant huntingtin exon 1 (HttEx1), which self-assembles into pathogenic neuronal inclusions in Huntington disease (HD). The mutant protein’s expanded polyglutamine (polyQ) segment forms a fibril core that is rigid and sequestered from the solvent. Beyond the core, solvent-exposed surface residues mediate biological interactions and other properties of fibril polymorphs. Here we deploy magic angle spinning ssNMR experiments to probe for semi-rigid residues proximal to the fibril core and examine how solvent dynamics impact the fibrils’ segmental dynamics. Dynamic spectral editing (DYSE) 2D ssNMR based on a combination of cross-polarization (CP) ssNMR with selective dipolar dephasing reveals the weak signals of solvent-mobilized glutamine residues, while suppressing the normally strong background of rigid core signals. This type of ‘intermediate motion selection’ (IMS) experiment based on cross-polarization (CP) ssNMR, is complementary to INEPT- and CP-based measurements that highlight highly flexible or highly rigid protein segments, respectively. Integration of the IMS-DYSE element in standard CP-based ssNMR experiments permits the observation of semi-rigid residues in a variety of contexts, including in membrane proteins and protein complexes. We discuss the relevance of semi-rigid solvent-facing residues outside the fibril core to the latter’s detection with specific dyes and positron emission tomography tracers.
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17
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Quantitative NMR analysis of the kinetics of prenucleation oligomerization and aggregation of pathogenic huntingtin exon-1 protein. Proc Natl Acad Sci U S A 2022; 119:e2207690119. [PMID: 35858329 PMCID: PMC9303973 DOI: 10.1073/pnas.2207690119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The N-terminal region of the huntingtin protein, encoded by exon-1 (httex1) and containing an expanded polyglutamine tract, forms fibrils that accumulate in neuronal inclusion bodies, resulting in Huntington's disease. We previously showed that reversible formation of a sparsely populated tetramer of the N-terminal amphiphilic domain, comprising a dimer of dimers in a four-helix bundle configuration, occurs on the microsecond timescale and is an essential prerequisite for subsequent nucleation and fibril formation that takes place orders of magnitude slower on a timescale of hours. For pathogenic httex1, such as httex1Q35 with 35 glutamines, NMR signals decay too rapidly to permit measurement of time-intensive exchange-based experiments. Here, we show that quantitative analysis of both the kinetics and mechanism of prenucleation tetramerization and aggregation can be obtained simultaneously from a series of 1H-15N band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence (SOFAST-HMQC) correlation spectra. The equilibria and kinetics of tetramerization are derived from the time dependence of the 15N chemical shifts and 1H-15N cross-peak volume/intensity ratios, while the kinetics of irreversible fibril formation are afforded by the decay curves of 1H-15N cross-peak intensities and volumes. Analysis of data on httex1Q35 over a series of concentrations ranging from 200 to 750 μM and containing variable (7 to 20%) amounts of the Met7O sulfoxide species, which does not tetramerize, shows that aggregation of native httex1Q35 proceeds via fourth-order primary nucleation, consistent with the critical role of prenucleation tetramerization, coupled with first-order secondary nucleation. The Met7O sulfoxide species does not nucleate but is still incorporated into fibrils by elongation.
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18
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Nazarov S, Chiki A, Boudeffa D, Lashuel HA. Structural Basis of Huntingtin Fibril Polymorphism Revealed by Cryogenic Electron Microscopy of Exon 1 HTT Fibrils. J Am Chem Soc 2022; 144:10723-10735. [PMID: 35679155 DOI: 10.1021/jacs.2c00509] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The lack of detailed insight into the structure of aggregates formed by the huntingtin protein (HTT) has hampered the efforts to develop therapeutics and diagnostics targeting pathology formation in the brain of patients with Huntington's disease. To address this knowledge gap, we investigated the structural properties of in vitro-generated fibrils from exon1 of the huntingtin protein by cryogenic electron microscopy and single-particle analyses. We show that wildtype and mutant exon1 of the huntingtin protein form nonhelical fibrils with a polyglutamine amyloid core composed of β-hairpins with unique characteristics that have not been previously observed with other amyloid filaments. The stacks of β-hairpins form long planar β-sheets (protofilaments) which combine inter- and intra-molecular interactions, with variable stacking angles and occasional out-of-register states of individual β-hairpins. These features and the propensity of protofilaments to undergo lateral association result in a high degree of fibril polymorphisms, including fibrils composed of varying numbers of protofilaments. Our results allow us to speculate on how the flanking domains are organized around the polyglutamine core of the fibril and provide insight into how they might affect the huntingtin fibril structure and polymorphism. The removal of the first 17 amino acids at the N-terminus resulted in surprising intra-fibril structural heterogeneity and reduced fibril's propensity to lateral associations. Overall, this work provides valuable insights that could help guide future mechanistic studies to elucidate the sequence and structural determinants of huntingtin aggregation, as well as for cryo-EM and structural studies of fibrils derived from huntingtin protein and other disease-associated polyglutamine-containing proteins.
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Affiliation(s)
- Sergey Nazarov
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.,BioEM Core Facility and Technology Platform, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Driss Boudeffa
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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19
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Molecular Pathophysiological Mechanisms in Huntington's Disease. Biomedicines 2022; 10:biomedicines10061432. [PMID: 35740453 PMCID: PMC9219859 DOI: 10.3390/biomedicines10061432] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/11/2022] Open
Abstract
Huntington’s disease is an inherited neurodegenerative disease described 150 years ago by George Huntington. The genetic defect was identified in 1993 to be an expanded CAG repeat on exon 1 of the huntingtin gene located on chromosome 4. In the following almost 30 years, a considerable amount of research, using mainly animal models or in vitro experiments, has tried to unravel the complex molecular cascades through which the transcription of the mutant protein leads to neuronal loss, especially in the medium spiny neurons of the striatum, and identified excitotoxicity, transcriptional dysregulation, mitochondrial dysfunction, oxidative stress, impaired proteostasis, altered axonal trafficking and reduced availability of trophic factors to be crucial contributors. This review discusses the pathogenic cascades described in the literature through which mutant huntingtin leads to neuronal demise. However, due to the ubiquitous presence of huntingtin, astrocytes are also dysfunctional, and neuroinflammation may additionally contribute to Huntington’s disease pathology. The quest for therapies to delay the onset and reduce the rate of Huntington’s disease progression is ongoing, but is based on findings from basic research.
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20
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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: 6] [Impact Index Per Article: 2.0] [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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21
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van der Wel PCA. Dihedral Angle Measurements for Structure Determination by Biomolecular Solid-State NMR Spectroscopy. Front Mol Biosci 2021; 8:791090. [PMID: 34938776 PMCID: PMC8685456 DOI: 10.3389/fmolb.2021.791090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
In structural studies of immobilized, aggregated and self-assembled biomolecules, solid-state NMR (ssNMR) spectroscopy can provide valuable high-resolution structural information. Among the structural restraints provided by magic angle spinning (MAS) ssNMR the canonical focus is on inter-atomic distance measurements. In the current review, we examine the utility of ssNMR measurements of angular constraints, as a complement to distance-based structure determination. The focus is on direct measurements of angular restraints via the judicious recoupling of multiple anisotropic ssNMR parameters, such as dipolar couplings and chemical shift anisotropies. Recent applications are highlighted, with a focus on studies of nanocrystalline polypeptides, aggregated peptides and proteins, receptor-substrate interactions, and small molecule interactions with amyloid protein fibrils. The review also examines considerations of when and where ssNMR torsion angle experiments are (most) effective, and discusses challenges and opportunities for future applications.
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Affiliation(s)
- Patrick C. A. van der Wel
- Solid-state NMR Group, Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
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22
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Perlikowska R. Whether short peptides are good candidates for future neuroprotective therapeutics? Peptides 2021; 140:170528. [PMID: 33716091 DOI: 10.1016/j.peptides.2021.170528] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/18/2021] [Accepted: 02/27/2021] [Indexed: 02/07/2023]
Abstract
Neurodegenerative diseases are a broad group of largely debilitating, and ultimately terminal conditions resulting in progressive degeneration of different brain regions. The observed damages are associated with cell death, structural and functional deficits of neurons, or demyelination. The concept of neuroprotection concerns the administration of the agent, which should reverse some of the damage or prevent further adverse changes. A growing body of evidence suggested that among many classes of compounds considered as neuroprotective agents, peptides derived from natural materials or their synthetic analogs are good candidates. They presented a broad spectrum of activities and abilities to act through diverse mechanisms of action. Biologically active peptides have many properties, including antioxidant, antimicrobial, antiinflammatory, and immunomodulatory effects. Peptides with pro-survival and neuroprotective activities, associated with inhibition of oxidative stress, apoptosis, inflammation and are able to improve cell viability or mitochondrial functions, are also promising molecules of particular interest to the pharmaceutical industries. Peptide multiple activities open the way for broad application potential as therapeutic agents or ingredients of health-promoting functional foods. Significantly, synthetic peptides can be remodeled in numerous ways to have desired features, such as increased solubility or biological stability, as well as selectivity towards a specific receptor, and finally better membrane penetration. This review summarized the most common features of major neurodegenerative disorders, their causes, consequences, and reported new neuroprotective drug development approaches. The author focused on the unique perspectives in neuroprotection and provided a concise survey of short peptides proposed as novel therapeutic agents against various neurodegenerative diseases.
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Affiliation(s)
- Renata Perlikowska
- Department of Biomolecular Chemistry, Faculty of Medicine, Medical University of Lodz, 92-215, Lodz, Poland.
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23
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Inhibition of p38 Mitogen-Activated Protein Kinase Ameliorates HAP40 Depletion-Induced Toxicity and Proteasomal Defect in Huntington's Disease Model. Mol Neurobiol 2021; 58:2704-2723. [PMID: 33492644 DOI: 10.1007/s12035-020-02280-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/30/2020] [Indexed: 02/07/2023]
Abstract
Huntington's disease (HD) is a progressive neurodegenerative disorder caused by an expansion of polyglutamine stretch (polyQ) at the N-terminus of huntingtin (Htt) protein. The abnormally expanded polyQ stretch of mutant Htt makes it prone to aggregate, leading to neuropathology. HAP40 is a 40-kDa huntingtin-associated protein with undefined functions. HAP40 protein has been shown to increase in HD patients and HD mouse model cells. However, recent proteomic analysis provides new evidence that HAP40 protein is decreased in the striatum of HD knockin model mice. In this study, we developed HAP40-specific antibody and showed that both HAP40 mRNA and its encoded protein were reduced in HD striatal neuronal STHDHQ111/Q111 cells. Depletion of endogenous HAP40 led to cytotoxicity that was linked to increased accumulation of aggregated and soluble forms of mutant Htt, which recapitulates HD pathology. Moreover, we found that HAP40 depletion reduced the proteasomal chymotrypsin-like activity and increased the autophagic flux. Importantly, inhibition of p38 MAPK pathway by PD169316 increased chymotrypsin-like activity and reduced accumulation of aggregated and soluble forms of mutant Htt in HAP40-depleted cells to alleviate HAP40-depletion induced cytotoxicity. Taken together, our results suggest that modulation of p38 MAPK-mediated proteasomal peptidase activity may provide a new therapeutic target to restore proteostasis in neurodegenerative diseases.
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24
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Chavali S, Singh AK, Santhanam B, Babu MM. Amino acid homorepeats in proteins. Nat Rev Chem 2020; 4:420-434. [PMID: 37127972 DOI: 10.1038/s41570-020-0204-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2020] [Indexed: 12/16/2022]
Abstract
Amino acid homorepeats, or homorepeats, are polypeptide segments found in proteins that contain stretches of identical amino acid residues. Although abnormal homorepeat expansions are linked to pathologies such as neurodegenerative diseases, homorepeats are prevalent in eukaryotic proteomes, suggesting that they are important for normal physiology. In this Review, we discuss recent advances in our understanding of the biological functions of homorepeats, which range from facilitating subcellular protein localization to mediating interactions between proteins across diverse cellular pathways. We explore how the functional diversity of homorepeat-containing proteins could be linked to the ability of homorepeats to adopt different structural conformations, an ability influenced by repeat composition, repeat length and the nature of flanking sequences. We conclude by highlighting how an understanding of homorepeats will help us better characterize and develop therapeutics against the human diseases to which they contribute.
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Affiliation(s)
- Sreenivas Chavali
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India.
| | - Anjali K Singh
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Balaji Santhanam
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
- Department of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - M Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
- Department of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN, USA.
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25
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Boatz JC, Piretra T, Lasorsa A, Matlahov I, Conway JF, van der Wel PCA. Protofilament Structure and Supramolecular Polymorphism of Aggregated Mutant Huntingtin Exon 1. J Mol Biol 2020; 432:4722-4744. [PMID: 32598938 DOI: 10.1016/j.jmb.2020.06.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 06/01/2020] [Accepted: 06/18/2020] [Indexed: 12/11/2022]
Abstract
Huntington's disease is a progressive neurodegenerative disease caused by expansion of the polyglutamine domain in the first exon of huntingtin (HttEx1). The extent of expansion correlates with disease progression and formation of amyloid-like protein deposits within the brain. The latter display polymorphism at the microscopic level, both in cerebral tissue and in vitro. Such polymorphism can dramatically influence cytotoxicity, leading to much interest in the conditions and mechanisms that dictate the formation of polymorphs. We examine conditions that govern HttEx1 polymorphism in vitro, including concentration and the role of the non-polyglutamine flanking domains. Using electron microscopy, we observe polymorphs that differ in width and tendency for higher-order bundling. Strikingly, aggregation yields different polymorphs at low and high concentrations. Narrow filaments dominate at low concentrations that may be more relevant in vivo. We dissect the role of N- and C-terminal flanking domains using protein with the former (httNT or N17) largely removed. The truncated protein is generated by trypsin cleavage of soluble HttEx1 fusion protein, which we analyze in some detail. Dye binding and solid-state NMR studies reveal changes in fibril surface characteristics and flanking domain mobility. Higher-order interactions appear facilitated by the C-terminal tail, while the polyglutamine forms an amyloid core resembling those of other polyglutamine deposits. Fibril-surface-mediated branching, previously attributed to secondary nucleation, is reduced in absence of httNT. A new model for the architecture of the HttEx1 filaments is presented and discussed in context of the assembly mechanism and biological activity.
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Affiliation(s)
- Jennifer C Boatz
- Department of Structural Biology, School of Medicine, University of Pittsburgh, 3501 5th Ave, Biomedical Science Tower 3, Pittsburgh, PA 15213, USA.
| | - Talia Piretra
- Department of Structural Biology, School of Medicine, University of Pittsburgh, 3501 5th Ave, Biomedical Science Tower 3, Pittsburgh, PA 15213, USA.
| | - Alessia Lasorsa
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands.
| | - Irina Matlahov
- Department of Structural Biology, School of Medicine, University of Pittsburgh, 3501 5th Ave, Biomedical Science Tower 3, Pittsburgh, PA 15213, USA; Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands.
| | - James F Conway
- Department of Structural Biology, School of Medicine, University of Pittsburgh, 3501 5th Ave, Biomedical Science Tower 3, Pittsburgh, PA 15213, USA.
| | - Patrick C A van der Wel
- Department of Structural Biology, School of Medicine, University of Pittsburgh, 3501 5th Ave, Biomedical Science Tower 3, Pittsburgh, PA 15213, USA; Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands.
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26
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Miao K, Wei L. Live-Cell Imaging and Quantification of PolyQ Aggregates by Stimulated Raman Scattering of Selective Deuterium Labeling. ACS CENTRAL SCIENCE 2020; 6:478-486. [PMID: 32341997 PMCID: PMC7181319 DOI: 10.1021/acscentsci.9b01196] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Indexed: 05/05/2023]
Abstract
Polyglutamine (polyQ) diseases are a group of neurodegenerative disorders, involving the deposition of aggregation-prone proteins with long polyQ expansions. However, the cytotoxic roles of these aggregates remain highly controversial, largely due to a lack of proper tools for quantitative and nonperturbative interrogations. Common methods including in vitro biochemical, spectroscopic assays, and live-cell fluorescence imaging all suffer from certain limitations. Here, we propose coupling stimulated Raman scattering microscopy with deuterium-labeled glutamine for live-cell imaging, quantification, and spectral analysis of native polyQ aggregates with subcellular resolution. First, through the enrichment of deuterated glutamine in the polyQ sequence of mutant Huntingtin (mHtt) exon1 proteins for Huntington's disease, we achieved sensitive and specific stimulated Raman scattering (SRS) imaging of carbon-deuterium bonds (C-D) from aggregates without GFP labeling, which is commonly employed in fluorescence microscopy. We revealed that these aggregates became 1.8-fold denser compared to those with GFP. Second, we performed ratiometric quantifications, which indicate a surprising dependence of protein compositions on aggregation sizes. Our further calculations, for the first time, reported the absolute concentrations for sequestered mHtt and non-mHtt proteins within the same aggregates. Third, we adopted hyperspectral SRS for Raman spectroscopic studies of aggregate structures. By inducing a cellular heat shock response, a potential therapeutic approach for inhibiting aggregate formation, we found a possible aggregate intermediate state with changed solvation microenvironments. Our method may hence readily unveil new features and mechanistic insight of polyQ aggregates and pave the way for comprehensive in vivo investigations.
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27
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Thompson TB, Kovall RA. Structural biology: Gaining atomic level insight into the biological function of macromolecules. Exp Biol Med (Maywood) 2019; 244:1507-1509. [PMID: 31718278 DOI: 10.1177/1535370219887678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Thomas B Thompson
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, OH 45267, USA
| | - Rhett A Kovall
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, OH 45267, USA
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