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Mishra R, Gerlach GJ, Sahoo B, Camacho CJ, Wetzel R. A Targetable Self-association Surface of the Huntingtin exon1 Helical Tetramer Required for Assembly of Amyloid Pre-nucleation Oligomers. J Mol Biol 2024; 436:168607. [PMID: 38734203 DOI: 10.1016/j.jmb.2024.168607] [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: 12/13/2023] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/13/2024]
Abstract
Polyglutamine (polyQ) sequences undergo repeat-length dependent formation of disease-associated, amyloid-like cross-β core structures with kinetics and aggregate morphologies often influenced by the flanking sequences. In Huntington's disease (HD), the httNT segment on the polyQ's N-terminal flank enhances aggregation rates by changing amyloid nucleation from a classical homogeneous mechanism to a two-step process requiring an ɑ-helix-rich oligomeric intermediate. A folded, helix-rich httNT tetrameric structure suggested to be this critical intermediate was recently reported. Here we employ single alanine replacements along the httNT sequence to assess this proposed structure and refine the mechanistic model. We find that Ala replacement of hydrophobic residues within simple httNT peptides greatly suppresses helicity, supporting the tetramer model. These same helix-disruptive replacements in the httNT segment of an exon-1 analog greatly reduce aggregation kinetics, suggesting that an ɑ-helix rich multimer - either the tetramer or a larger multimer - plays an on-pathway role in nucleation. Surprisingly, several other Ala replacements actually enhance helicity and/or amyloid aggregation. The spatial localization of these residues on the tetramer surface suggests a self-association interface responsible for formation of the octomers and higher-order multimers most likely required for polyQ amyloid nucleation. Multimer docking of the tetramer, using the protein-protein docking algorithm ClusPro, predicts this symmetric surface to be a viable tetramer dimerization interface. Intriguingly, octomer formation brings the emerging polyQ chains into closer proximity at this tetramer-tetramer interface. Further supporting the potential importance of tetramer super-assembly, computational docking with a known exon-1 aggregation inhibitor predicts ligand contacts with residues at this interface.
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Affiliation(s)
- Rakesh Mishra
- Department Structural Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
| | - Gabriella J Gerlach
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA
| | - Bankanidhi Sahoo
- Department Structural Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
| | - Carlos J Camacho
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
| | - Ronald Wetzel
- Department Structural Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
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2
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Chang CY, Wang SSS, Lai YR, Koh WG, Wu JW, Chiang YH. Ophthalmic drug effects on the amyloidogenesis of a transforming growth factor β-induced protein (TGFBIp) peptide fragment. Exp Eye Res 2024; 244:109932. [PMID: 38762008 DOI: 10.1016/j.exer.2024.109932] [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: 11/05/2023] [Revised: 03/30/2024] [Accepted: 05/15/2024] [Indexed: 05/20/2024]
Abstract
Drugs that can treat one disease may either be detrimental or beneficial toward another due to possible cross-interactions. Therefore, care in choosing a suitable drug for patients with multiple diseases is crucial in successful patient management. This study explores several currently available ophthalmic drugs used to treat common ocular diseases to understand how they can affect the amyloidogenesis of a transforming growth factor β-induced protein (TGFBIp) peptide fragment found in abundance in the corneal protein aggregation deposits of lattice corneal dystrophy (LCD) patients. Results from this study provided supporting evidence that some drugs intended to treat other diseases can enhance or inhibit fibrillar aggregation of TGFBIp peptide, which may have potential implication of affecting the disease progression of LCD by either worsening or ameliorating it. Comparisons of the different properties of ophthalmic compounds explored in this study may also provide some guidance for future design of drugs geared toward the treatment of LCD.
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Affiliation(s)
- Chia-Yu Chang
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan
| | - Steven S-S Wang
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan
| | - You-Ren Lai
- Department of Chemical Engineering, National Taiwan University, Taipei, 10617, Taiwan
| | - Won-Gun Koh
- Department of Chemical and Biomolecular Engineering, Yonsei University, South Korea
| | - Josephine W Wu
- Department of Optometry, Yuanpei University of Medical Technology, Hsinchu City, 30015, Taiwan; Department of Optometry, Mackay Medical College, New Taipei City, 252, Taiwan.
| | - Yi-Hui Chiang
- Department of Ophthalmology, En Chu Kong Hospital, New Taipei City, 237, Taiwan.
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3
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Tandon S, Aggarwal P, Sarkar S. Polyglutamine disorders: Pathogenesis and potential drug interventions. Life Sci 2024; 344:122562. [PMID: 38492921 DOI: 10.1016/j.lfs.2024.122562] [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: 11/02/2023] [Revised: 02/27/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024]
Abstract
Polyglutamine/poly(Q) diseases are a group nine hereditary neurodegenerative disorders caused due to abnormally expanded stretches of CAG trinucleotide in functionally distinct genes. All human poly(Q) diseases are characterized by the formation of microscopically discernable poly(Q) positive aggregates, the inclusion bodies. These toxic inclusion bodies are responsible for the impairment of several cellular pathways such as autophagy, transcription, cell death, etc., that culminate in disease manifestation. Although, these diseases remain largely without treatment, extensive research has generated mounting evidences that various events of poly(Q) pathogenesis can be developed as potential drug targets. The present review article briefly discusses the key events of disease pathogenesis, model system-based investigations that support the development of effective therapeutic interventions against pathogenesis of human poly(Q) disorders, and a comprehensive list of pharmacological and bioactive compounds that have been experimentally shown to alleviate poly(Q)-mediated neurotoxicity. Interestingly, due to the common cause of pathogenesis, all poly(Q) diseases share etiology, thus, findings from one disease can be potentially extrapolated to other poly(Q) diseases as well.
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Affiliation(s)
- Shweta Tandon
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Prerna Aggarwal
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Surajit Sarkar
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.
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4
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Geijtenbeek KW, Aranda AS, Sanz AS, Janzen J, Bury AE, Kors S, Al Amery N, Schmitz NCM, Reits EAJ, Schipper-Krom S. Insulin-Degrading Enzyme Efficiently Degrades polyQ Peptides but not Expanded polyQ Huntingtin Fragments. J Huntingtons Dis 2024:JHD230583. [PMID: 38640164 DOI: 10.3233/jhd-230583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
Background Huntington's disease is an inheritable autosomal dominant disorder caused by an expanded CAG trinucleotide repeat within the Huntingtin gene, leading to a polyglutamine (polyQ) expansion in the mutant protein. Objective A potential therapeutic approach for delaying or preventing the onset of the disease involves enhancing the degradation of the aggregation-prone polyQ-expanded N-terminal mutant huntingtin (mHTT) exon1 fragment. A few proteases and peptidases have been identified that are able to cleave polyQ fragments with low efficiency. This study aims to identify a potent polyQ-degrading endopeptidase. Methods Here we used quenched polyQ peptides to identify a polyQ-degrading endopeptidase. Next we investigated its role on HTT turnover, using purified polyQ-expanded HTT fragments and striatal cells expressing mHTT exon1 peptides. Results We identified insulin-degrading enzyme (IDE) as a novel endopeptidase for degrading polyQ peptides. IDE was, however, ineffective in reducing purified polyQ-expanded HTT fragments. Similarly, in striatal cells expressing mHTT exon1 peptides, IDE did not enhance mHTT turnover. Conclusions This study shows that despite IDE's efficiency in degrading polyQ peptides, it does not contribute to the direct degradation of polyQ-expanded mHTT fragments.
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Affiliation(s)
- Karlijne W Geijtenbeek
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Angela Santiago Aranda
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Alicia Sanz Sanz
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Jolien Janzen
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Aleksandra E Bury
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Suzan Kors
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | | | - Nina C M Schmitz
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Eric A J Reits
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
| | - Sabine Schipper-Krom
- Amsterdam UMC, University of Amsterdam, Medical Biology, Meibergdreef, Amsterdam, Netherlands
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5
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Yang T, Xue T, Mao J, Chen Y, Tian H, Bartolome A, Xia H, Yao X, Kumar CV, Cheng J, Lin Y. Tailoring Synthetic Polypeptide Design for Directed Fibril Superstructure Formation and Enhanced Hydrogel Properties. J Am Chem Soc 2024; 146:5823-5833. [PMID: 38174701 DOI: 10.1021/jacs.3c10762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The biological significance of self-assembled protein filament networks and their unique mechanical properties have sparked interest in the development of synthetic filament networks that mimic these attributes. Building on the recent advancement of autoaccelerated ring-opening polymerization of amino acid N-carboxyanhydrides (NCAs), this study strategically explores a series of random copolymers comprising multiple amino acids, aiming to elucidate the core principles governing gelation pathways of these purpose-designed copolypeptides. Utilizing glutamate (Glu) as the primary component of copolypeptides, two targeted pathways were pursued: first, achieving a fast fibrillation rate with lower interaction potential using serine (Ser) as a comonomer, facilitating the creation of homogeneous fibril networks; and second, creating more rigid networks of fibril clusters by incorporating alanine (Ala) and valine (Val) as comonomers. The selection of amino acids played a pivotal role in steering both the morphology of fibril superstructures and their assembly kinetics, subsequently determining their potential to form sample-spanning networks. Importantly, the viscoelastic properties of the resulting supramolecular hydrogels can be tailored according to the specific copolypeptide composition through modulations in filament densities and lengths. The findings enhance our understanding of directed self-assembly in high molecular weight synthetic copolypeptides, offering valuable insights for the development of synthetic fibrous networks and biomimetic supramolecular materials with custom-designed properties.
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Affiliation(s)
- Tianjian Yang
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Tianrui Xue
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jianan Mao
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Yingying Chen
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Huidi Tian
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Arlene Bartolome
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Hongwei Xia
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Xudong Yao
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Challa V Kumar
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Jianjun Cheng
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yao Lin
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
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6
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Lobato AG, Ortiz-Vega N, Zhu Y, Neupane D, Meier KK, Zhai RG. Copper enhances aggregational toxicity of mutant huntingtin in a Drosophila model of Huntington's Disease. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166928. [PMID: 38660915 PMCID: PMC11046041 DOI: 10.1016/j.bbadis.2023.166928] [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: 08/04/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 04/26/2024]
Abstract
Huntington's disease (HD) is a progressive neurodegenerative disorder with clinical presentations of moderate to severe cognitive, motor, and psychiatric disturbances. HD is caused by the trinucleotide repeat expansion of CAG of the huntingtin (HTT) gene. The mutant HTT protein containing pathological polyglutamine (polyQ) extension is prone to misfolding and aggregation in the brain. It has previously been observed that copper and iron concentrations are increased in the striata of post-mortem human HD brains. Although it has been shown that the accumulation of mutant HTT protein can interact with copper, the underlying HD progressive phenotypes due to copper overload remains elusive. Here, in a Drosophila model of HD, we showed that copper induces dose-dependent aggregational toxicity and enhancement of Htt-induced neurodegeneration. Specifically, we found that copper increases mutant Htt aggregation, enhances the accumulation of Thioflavin S positive β-amyloid structures within Htt aggregates, and consequently alters autophagy in the brain. Administration of copper chelator D-penicillamine (DPA) through feeding significantly decreases β-amyloid aggregates in the HD pathological model. These findings reveal a direct role of copper in potentiating mutant Htt protein-induced aggregational toxicity, and further indicate the potential impact of environmental copper exposure in the disease onset and progression of HD.
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Affiliation(s)
- Amanda G Lobato
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA; Graduate Program in Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Natalie Ortiz-Vega
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA; Graduate Program in Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Yi Zhu
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Deepa Neupane
- Graduate Program in Chemistry, University of Miami, Coral Gables, Florida, USA; Department of Chemistry, University of Miami, Coral Gables, Florida, USA
| | - Katlyn K Meier
- Department of Chemistry, University of Miami, Coral Gables, Florida, USA
| | - R Grace Zhai
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA.
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7
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Zhang H, Lv S, Jin C, Ren F, Wang J. Wheat gluten amyloid fibrils: Conditions, mechanism, characterization, application, and future perspectives. Int J Biol Macromol 2023; 253:126435. [PMID: 37611682 DOI: 10.1016/j.ijbiomac.2023.126435] [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: 04/18/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/25/2023]
Abstract
Amyloid fibrils have excellent structural characteristics, such as a high aspect ratio, excellent stiffness, and a wide availability of functional groups on the surface. More studies are now focusing on the formation of amyloid fibrils using food proteins. Protein fibrillation is now becoming recognized as a promising strategy for enhancing the function of food proteins and expanding their range of applications. Wheat gluten is rich in glutamine (Q), hydrophobic amino acids, and the α-helix structure with high β-sheet tendency. These characteristics make it very easy for wheat gluten to form amyloid fibrils. The conditions, formation mechanism, characterization methods, and application of amyloid fibrils formed by wheat gluten are summarized in this review. Further exploration of amyloid fibrils formed by wheat gluten will reveal how they can play a significant role in food, biology, and other fields, especially in medicine.
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Affiliation(s)
- Huijuan Zhang
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China.
| | - Shihao Lv
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China
| | - Chengming Jin
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China
| | - Feiyue Ren
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China
| | - Jing Wang
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China.
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8
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Stonebraker AR, Hankin R, Kapp KL, Li P, Valentine SJ, Legleiter J. Charge within Nt17 peptides modulates huntingtin aggregation and initial lipid binding events. Biophys Chem 2023; 303:107123. [PMID: 37852163 PMCID: PMC10843285 DOI: 10.1016/j.bpc.2023.107123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/22/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023]
Abstract
Toxic aggregation of pathogenic huntingtin protein (htt) is implicated in Huntington's disease and influenced by various factors, including the first seventeen amino acids at the N-terminus (Nt17) and the presence of lipid membranes. Nt17 has a propensity to form an amphipathic α-helix in the presence of binding partners, which promotes α-helix rich oligomer formation and facilitates htt/lipid interactions. Within Nt17 are multiple sites that are subject to post-translational modification, including acetylation and phosphorylation. Acetylation can occur at lysine 6, 9, and/or 15 while phosphorylation can occur at threonine 3, serine 13, and/or serine 16. Such modifications impact aggregation and lipid binding through the alteration of various intra- and intermolecular interactions. When incubated with htt-exon1(46Q), free Nt17 peptides containing point mutations mimicking acetylation or phosphorylation reduced fibril formation and altered oligomer morphologies. Upon exposure to lipid vesicles, changes to peptide/lipid complexation were observed and peptide-containing oligomers demonstrated reduced lipid interactions.
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Affiliation(s)
- Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Rachel Hankin
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Kathryn L Kapp
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Peng Li
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA; Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, USA.
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9
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Lipiński WP, Zehnder J, Abbas M, Güntert P, Spruijt E, Wiegand T. Fibrils Emerging from Droplets: Molecular Guiding Principles behind Phase Transitions of a Short Peptide-Based Condensate Studied by Solid-State NMR. Chemistry 2023; 29:e202301159. [PMID: 37310801 DOI: 10.1002/chem.202301159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/10/2023] [Accepted: 06/13/2023] [Indexed: 06/15/2023]
Abstract
Biochemical reactions occurring in highly crowded cellular environments require different means of control to ensure productivity and specificity. Compartmentalization of reagents by liquid-liquid phase separation is one of these means. However, extremely high local protein concentrations of up to 400 mg/ml can result in pathological aggregation into fibrillar amyloid structures, a phenomenon that has been linked to various neurodegenerative diseases. Despite its relevance, the process of liquid-to-solid transition inside condensates is still not well understood at the molecular level. We thus herein use small peptide derivatives that can undergo both liquid-liquid and subsequent liquid-to-solid phase transition as model systems to study both processes. Using solid-state nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM), we compare the structure of condensed states of leucine, tryptophan and phenylalanine containing derivatives, distinguishing between liquid-like condensates, amorphous aggregates and fibrils, respectively. A structural model for the fibrils formed by the phenylalanine derivative was obtained by an NMR-based structure calculation. The fibrils are stabilised by hydrogen bonds and side-chain π-π interactions, which are likely much less pronounced or absent in the liquid and amorphous state. Such noncovalent interactions are equally important for the liquid-to-solid transition of proteins, particularly those related to neurodegenerative diseases.
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Affiliation(s)
- Wojciech P Lipiński
- Radboud University, Institute of Molecules and Materials (IMM), Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Johannes Zehnder
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland
| | - Manzar Abbas
- Radboud University, Institute of Molecules and Materials (IMM), Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Peter Güntert
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland
- Institute of Biophysical Chemistry Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max-von-Laue-Str. 9, 60438, Frankfurt am Main, Germany
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji-shi, 192-0397, Tokyo, Japan
| | - Evan Spruijt
- Radboud University, Institute of Molecules and Materials (IMM), Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Thomas Wiegand
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany
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10
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Zhang H, Lv S, Ren F, Liu J, Wang J. Degree of Hydrolysis Regulated by Enzyme Mediation of Wheat Gluten Fibrillation: Structural Characterization and Analysis of the Mechanism of Action. Int J Mol Sci 2023; 24:13529. [PMID: 37686349 PMCID: PMC10488075 DOI: 10.3390/ijms241713529] [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: 08/02/2023] [Revised: 08/26/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023] Open
Abstract
The impact of different degrees of hydrolysis (DHs) on fibrillation when trypsin mediates wheat gluten (WG) fibrillation has not been thoroughly investigated. This study discussed the differences in amyloid fibrils (AFs) formed from wheat gluten peptides (WGPs) at various DH values. The results from Thioflavin T (ThT) fluorescence analysis indicated that WGPs with DH6 were able to form the most AFs. Changes in Fourier Transform Infrared (FTIR) absorption spectra and secondary structure also suggested a higher degree of fibrillation in DH6 WGPs. Analysis of surface hydrophobicity and ζ-potential showed that DH6 AFs had the highest surface hydrophobicity and the most stable water solutions. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images revealed the best overall morphology of DH6 AFs. These findings can offer valuable insights into the development of a standardized method for preparing wheat gluten amyloid fibrils.
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Affiliation(s)
- Huijuan Zhang
- China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing 100048, China
- Key Laboratory of Special Food Supervision Technology for State Market Regulation, Beijing 100048, China
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China; (S.L.); (F.R.); (J.L.)
| | - Shihao Lv
- China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing 100048, China
- Key Laboratory of Special Food Supervision Technology for State Market Regulation, Beijing 100048, China
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China; (S.L.); (F.R.); (J.L.)
| | - Feiyue Ren
- China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing 100048, China
- Key Laboratory of Special Food Supervision Technology for State Market Regulation, Beijing 100048, China
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China; (S.L.); (F.R.); (J.L.)
| | - Jie Liu
- China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing 100048, China
- Key Laboratory of Special Food Supervision Technology for State Market Regulation, Beijing 100048, China
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China; (S.L.); (F.R.); (J.L.)
| | - Jing Wang
- China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing 100048, China
- Key Laboratory of Special Food Supervision Technology for State Market Regulation, Beijing 100048, China
- School of Food and Health, Beijing Technology & Business University (BTBU), Beijing 100048, China; (S.L.); (F.R.); (J.L.)
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11
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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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12
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Paladino A, Vitagliano L, Graziano G. The Action of Chemical Denaturants: From Globular to Intrinsically Disordered Proteins. BIOLOGY 2023; 12:biology12050754. [PMID: 37237566 DOI: 10.3390/biology12050754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023]
Abstract
Proteins perform their many functions by adopting either a minimal number of strictly similar conformations, the native state, or a vast ensemble of highly flexible conformations. In both cases, their structural features are highly influenced by the chemical environment. Even though a plethora of experimental studies have demonstrated the impact of chemical denaturants on protein structure, the molecular mechanism underlying their action is still debated. In the present review, after a brief recapitulation of the main experimental data on protein denaturants, we survey both classical and more recent interpretations of the molecular basis of their action. In particular, we highlight the differences and similarities of the impact that denaturants have on different structural classes of proteins, i.e., globular, intrinsically disordered (IDP), and amyloid-like assemblies. Particular attention has been given to the IDPs, as recent studies are unraveling their fundamental importance in many physiological processes. The role that computation techniques are expected to play in the near future is illustrated.
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Affiliation(s)
- Antonella Paladino
- Institute of Biostructures and Bioimaging, CNR, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, CNR, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Giuseppe Graziano
- Department of Science and Technology, University of Sannio, via Francesco de Sanctis snc, 82100 Benevento, Italy
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13
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Liu H, Wang J, Liu M, Zhang X, Liang Y, Wang J. Effect of Thermal Treatment on the Self-Assembly of Wheat Gluten Polypeptide. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020834. [PMID: 36677896 PMCID: PMC9862778 DOI: 10.3390/molecules28020834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/30/2022] [Accepted: 01/12/2023] [Indexed: 01/17/2023]
Abstract
Self-assembled fibrillation of wheat gluten is a common phenomenon in the daily production and processing of wheat flour products. The driving forces for its formation and the factors that influence the morphology of fibrils have not been thoroughly investigated. In this study, the effect of three bonding changes (breaking hydrogen bonds, strengthening hydrophobic interactions, and SH-SS exchange reactions) on gluten polypeptide (GP) fibrillation was simulated by adjusting the heating temperature (room temperature (RT), 45 °C, 65 °C, and 95 °C). The results showed that the breakage of hydrogen bonds could induce conformational transitions in GPs and help to excite fibrillation in GPs. Strengthened hydrophobic interactions significantly contributed to the fibrillation of GPs. Covalent crosslinks generated by SH-SS exchange reactions might also promote the fibrillation of GPs. GPs with different degrees of hydrolysis (4.0%, 6.0%, and 10.0%, represented by DH 4, DH 6, and DH 10, respectively) presented different extents of fibrillation, with DH 10 GPs having a higher propensity to fibrillation than DH 4 and DH 6 GPs. The results of Fourier's transform infrared spectroscopy indicated that hydrophobic interactions drive the transition from a random coil and α-helix to a β-sheet. In addition, hydrophobic interactions also drive the intermolecular polymerization of GPs, resulting in larger molecular weight aggregates. The morphology presented by transmission electron microscopy showed that the greater the DH, the stronger the tendency for the worm-like aggregation of GPs.
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Affiliation(s)
- Hao Liu
- College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Jingxuan Wang
- College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Mei Liu
- College of Food Science and Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Xia Zhang
- College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Ying Liang
- College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
- Correspondence: (Y.L.); (J.W.); Tel./Fax: +86-0371-67756872 (Y.L.); +86-0371-67756512 (J.W.)
| | - Jinshui Wang
- College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
- Correspondence: (Y.L.); (J.W.); Tel./Fax: +86-0371-67756872 (Y.L.); +86-0371-67756512 (J.W.)
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14
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Bhat SA, Ahamad S, Dar NJ, Siddique YH, Nazir A. The Emerging Landscape of Natural Small-molecule Therapeutics for Huntington's Disease. Curr Neuropharmacol 2023; 21:867-889. [PMID: 36797612 PMCID: PMC10227909 DOI: 10.2174/1570159x21666230216104621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/12/2022] [Accepted: 11/18/2022] [Indexed: 02/18/2023] Open
Abstract
Huntington's disease (HD) is a rare and fatal neurodegenerative disorder with no diseasemodifying therapeutics. HD is characterized by extensive neuronal loss and is caused by the inherited expansion of the huntingtin (HTT) gene that encodes a toxic mutant HTT (mHTT) protein having expanded polyglutamine (polyQ) residues. Current HD therapeutics only offer symptomatic relief. In fact, Food and Drug Administration (FDA) approved two synthetic small-molecule VMAT2 inhibitors, tetrabenazine (1) and deutetrabenazine (2), for managing HD chorea and various other diseases in clinical trials. Therefore, the landscape of drug discovery programs for HD is evolving to discover disease- modifying HD therapeutics. Likewise, numerous natural products are being evaluated at different stages of clinical development and have shown the potential to ameliorate HD pathology. The inherent anti-inflammatory and antioxidant properties of natural products mitigate the mHTT-induced oxidative stress and neuroinflammation, improve mitochondrial functions, and augment the anti-apoptotic and pro-autophagic mechanisms for increased survival of neurons in HD. In this review, we have discussed HD pathogenesis and summarized the anti-HD clinical and pre-clinical natural products, focusing on their therapeutic effects and neuroprotective mechanism/s.
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Affiliation(s)
| | - Shakir Ahamad
- Department of Chemistry, Aligarh Muslim University, Aligarh, U.P., India
| | - Nawab John Dar
- School of Medicine, UT Health San Antonio, Texas, TX, USA
| | | | - Aamir Nazir
- Division of Neuroscience and Ageing Biology, CSIR-Central Drug Research Institute, Lucknow, U.P., India
- Academy of Scientific and Innovative Research, New Delhi, India
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15
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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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16
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Pillai M, Jha SK. Multistep molecular mechanism of amyloid-like aggregation of nucleic acid-binding domain of TDP-43. Proteins 2022; 91:649-664. [PMID: 36530161 DOI: 10.1002/prot.26455] [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: 05/02/2022] [Revised: 11/16/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
TDP-43 protein is associated with many neurodegenerative diseases and has been shown to adopt various oligomeric and fibrillar states. However, a detailed kinetic understanding of the structural transformation of the native form of the protein to the fibrillar state is missing. In this study, we delineate the temporal sequence of structural events during the amyloid-like assembly of the functional nucleic acid-binding domain of TDP-43. We kinetically mapped the aggregation process using multiple probes such as tryptophan and thioflavin T (ThT) fluorescence, circular dichroism (CD), and dynamic light scattering (DLS) targeting different structural events. Our data reveal that aggregation occurs in four distinct steps-very fast, fast, slow, and very slow. The "very fast" change results in partially unfolded forms that undergo conformational conversion, oligomerization and bind to ThT in the "fast step" to form higher order intermediates (HOI). The temporal sequence of the formation of ThT binding sites and conformational conversion depends upon the protein concentration. The HOI further undergoes structural rearrangement to form protofibrils in the "slow" step, which, consequently, assembles in the "very slow" step to form an amyloid-like assembly. The spectroscopic properties of the amyloid-like assembly across the protein concentration remain similar. Additionally, we observe no lag phase across protein concentration for all the probes studied, suggesting that the aggregation process follows a linear polymerization reaction. Overall, our study demonstrates that the amyloid-like assembly forms in multiple steps, which is also supported by the temperature dependence of the kinetics.
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Affiliation(s)
- Meenakshi Pillai
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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17
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Bhagavatula H, Sarkar A, Santra B, Das A. Scan-Find-Scan-Model: Discrete Site-Targeted Suppressor Design Strategy for Amyloid-β. ACS Chem Neurosci 2022; 13:2191-2208. [PMID: 35767676 DOI: 10.1021/acschemneuro.2c00272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease is undoubtedly the most well-studied neurodegenerative disease. Consequently, the amyloid-β (Aβ) protein ranks at the top in terms of getting attention from the scientific community for structural property-based characterization. Even after decades of extensive research, there is existing volatility in terms of understanding and hence the effective tackling procedures against the disease that arises due to the lack of knowledge of both specific target- and site-specific drugs. Here, we develop a multidimensional approach based on the characterization of the common static-dynamic-thermodynamic trait of the monomeric protein, which efficiently identifies a small target sequence that contains an inherent tendency to misfold and consequently aggregate. The robustness of the identification of the target sequence comes with an abundance of a priori knowledge about the length and sequence of the target and hence guides toward effective designing of the target-specific drug with a very low probability of bottleneck and failure. Based on the target sequence information, we further identified a specific mutant that showed the maximum potential to act as a destabilizer of the monomeric protein as well as enormous success as an aggregation suppressor. We eventually tested the drug efficacy by estimating the extent of modulation of binding affinity existing within the fibrillar form of the Aβ protein due to a single-point mutation and hence provided a proof of concept of the entire protocol.
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Affiliation(s)
- Hasathi Bhagavatula
- Department of Biotechnology, Progressive Education Society's Modern College of Arts Science and Commerce, Shivajinagar, Pune 411005, India
| | - Archishman Sarkar
- School of Applied and Interdisciplinary Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja Subodh Chandra Mallick Road, Kolkata, West Bengal 700032, India
| | - Binit Santra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kalyanpur, Kanpur, Uttar Pradesh 208016, India
| | - Atanu Das
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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18
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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: 0] [Impact Index Per Article: 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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19
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Sinnige T. Molecular mechanisms of amyloid formation in living systems. Chem Sci 2022; 13:7080-7097. [PMID: 35799826 PMCID: PMC9214716 DOI: 10.1039/d2sc01278b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/14/2022] [Indexed: 12/28/2022] Open
Abstract
Fibrillar protein aggregation is a hallmark of a variety of human diseases. Examples include the deposition of amyloid-β and tau in Alzheimer's disease, and that of α-synuclein in Parkinson's disease. The molecular mechanisms by which soluble proteins form amyloid fibrils have been extensively studied in the test tube. These investigations have revealed the microscopic steps underlying amyloid formation, and the role of factors such as chaperones that modulate these processes. This perspective explores the question to what extent the mechanisms of amyloid formation elucidated in vitro apply to human disease. The answer is not yet clear, and may differ depending on the protein and the associated disease. Nevertheless, there are striking qualitative similarities between the aggregation behaviour of proteins in vitro and the development of the related diseases. Limited quantitative data obtained in model organisms such as Caenorhabditis elegans support the notion that aggregation mechanisms in vivo can be interpreted using the same biophysical principles established in vitro. These results may however be biased by the high overexpression levels typically used in animal models of protein aggregation diseases. Molecular chaperones have been found to suppress protein aggregation in animal models, but their mechanisms of action have not yet been quantitatively analysed. Several mechanisms are proposed by which the decline of protein quality control with organismal age, but also the intrinsic nature of the aggregation process may contribute to the kinetics of protein aggregation observed in human disease. The molecular mechanisms of amyloid formation have been studied extensively in test tube reactions. This perspective article addresses the question to what extent these mechanisms apply to the complex situation in living cells and organisms.![]()
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Affiliation(s)
- Tessa Sinnige
- Bijvoet Centre for Biomolecular Research, Utrecht University Padualaan 8 3584 CH Utrecht The Netherlands
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20
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Hsueh SS, Lu JH, Wu JW, Lin TH, Wang SSS. Protection of human γD-crystallin protein from ultraviolet C-induced aggregation by ortho-vanillin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 261:120023. [PMID: 34098480 DOI: 10.1016/j.saa.2021.120023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
Cataract is known as one of the leading causes of vision impairment worldwide. While the detailed mechanism of cataratogenesis remains unclear, cataract is believed to be correlated with the aggregation and/or misfolding of human ocular lens proteins called crystallins. A 173-residue structural protein human γD-crystallin is a major γ-crystallin protein in the human eye lens and associated with the development of juvenile and mature-onset cataracts. This work is aimed at investigating the effect of a small molecule, e.g., ortho-vanillin, on human γD-crystallin aggregation upon exposure to ultraviolet-C irradiation. According to the findings of right-angle light scattering, transmission electron microscopy, and gel electrophoresis, ortho-vanillin was demonstrated to dose-dependently suppress ultraviolet-C-triggered aggregation of human γD-crystallin. Results from the synchronous fluorescence spectroscopy, tryptophan fluorescence quenching, and molecular docking studies revealed the structural change of γD-crystallin induced by the interaction/binding between ortho-vanillin and protein. We believe the outcome from this work may contribute to the development of potential therapeutics for cataract.
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Affiliation(s)
- Shu-Shun Hsueh
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Jian-Hong Lu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Josephine W Wu
- Department of Optometry, Yuanpei University of Medical Technology, Hsinchu City 30015, Taiwan.
| | - Ta-Hsien Lin
- Basic Research Division, Medical Research Department, Taipei Veterans General Hospital, Taipei 11217, Taiwan; Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan.
| | - Steven S-S Wang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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21
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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: 17] [Impact Index Per Article: 5.7] [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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22
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Fisher RS, Jimenez RM, Soto E, Kalev D, Elbaum-Garfinkle S. An apparent core/shell architecture of polyQ aggregates in the aging Caenorhabditis elegans neuron. Protein Sci 2021; 30:1482-1486. [PMID: 33966305 DOI: 10.1002/pro.4105] [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: 03/08/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 01/28/2023]
Abstract
Huntington's disease is caused by a polyglutamine (polyQ) expansion in the huntingtin protein which results in its abnormal aggregation in the nervous system. Huntingtin aggregates are linked to toxicity and neuronal dysfunction, but a comprehensive understanding of the aggregation mechanism in vivo remains elusive. Here, we examine the morphology of polyQ aggregates in Caenorhabditis elegans mechanosensory neurons as a function of age using confocal and fluorescence lifetime imaging microscopy. We find that aggregates in young worms are mostly spherical with homogenous intensity, but as the worm ages aggregates become substantially more heterogeneous. Most prominently, in older worms we observe an apparent core/shell morphology of polyQ assemblies with decreased intensity in the center. The fluorescence lifetime of polyQ is uniform across the aggregate indicating that the dimmed intensity in the assembly center is most likely not due to quenching or changes in local environment, but rather to displacement of fluorescent polyQ from the central region. This apparent core/shell architecture of polyQ aggregates in aging C. elegans neurons contributes to the diverse landscape of polyQ aggregation states implicated in Huntington's disease.
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Affiliation(s)
- Rachel S Fisher
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Rosa Meyo Jimenez
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Elizabeth Soto
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Darin Kalev
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA
| | - Shana Elbaum-Garfinkle
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, USA.,Ph.D. Programs in Biochemistry and Biology, The Graduate Center, CUNY, New York, New York, USA
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23
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Fonda BD, Jami KM, Boulos NR, Murray DT. Identification of the Rigid Core for Aged Liquid Droplets of an RNA-Binding Protein Low Complexity Domain. J Am Chem Soc 2021; 143:6657-6668. [PMID: 33896178 DOI: 10.1021/jacs.1c02424] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The biomolecular condensation of proteins with low complexity sequences plays a functional role in RNA metabolism and a pathogenic role in neurodegenerative diseases. The formation of dynamic liquid droplets brings biomolecules together to achieve complex cellular functions. The rigidification of liquid droplets into β-strand-rich hydrogel structures composed of protein fibrils is thought to be purely pathological in nature. However, low complexity sequences often harbor multiple fibril-prone regions with delicately balanced functional and pathological interactions. Here, we investigate the maturation of liquid droplets formed by the low complexity domain of the TAR DNA-binding protein 43 (TDP-43). Solid state nuclear magnetic resonance measurements on the aged liquid droplets identify residues 365-400 as the structured core, which are squarely outside the region between residues 311-360 thought to be most important for pathological fibril formation and aggregation. The results of this study suggest that multiple segments of this low complexity domain are prone to form fibrils and that stabilization of β-strand-rich structure in one segment precludes the other region from adopting a rigid fibril structure.
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Affiliation(s)
- Blake D Fonda
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Khaled M Jami
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Natalie R Boulos
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Dylan T Murray
- Department of Chemistry, University of California, Davis, California 95616, United States
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24
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Characterization of design grammar of peptides for regulating liquid droplets and aggregates of FUS. Sci Rep 2021; 11:6643. [PMID: 33758287 PMCID: PMC7988016 DOI: 10.1038/s41598-021-86098-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/10/2021] [Indexed: 12/12/2022] Open
Abstract
Liquid droplets of aggregation-prone proteins, which become hydrogels or form amyloid fibrils, are a potential target for drug discovery. In this study, we proposed an experiment-guided protocol for characterizing the design grammar of peptides that can regulate droplet formation and aggregation. The protocol essentially involves investigation of 19 amino acid additives and polymerization of the identified amino acids. As a proof of concept, we applied this protocol to fused in sarcoma (FUS). First, we evaluated 19 amino acid additives for an FUS solution and identified Arg and Tyr as suppressors of droplet formation. Molecular dynamics simulations suggested that the Arg additive interacts with specific residues of FUS, thereby inhibiting the cation-π and electrostatic interactions between the FUS molecules. Second, we observed that Arg polymers promote FUS droplet formation, unlike Arg monomers, by bridging the FUS molecules. Third, we found that the Arg additive suppressed solid aggregate formation of FUS, while Arg polymer enhanced it. Finally, we observed that amyloid-forming peptides induced the conversion of FUS droplets to solid aggregates of FUS. The developed protocol could be used for the primary design of peptides controlling liquid droplets and aggregates of proteins.
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25
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Kinetic analysis reveals that independent nucleation events determine the progression of polyglutamine aggregation in C. elegans. Proc Natl Acad Sci U S A 2021; 118:2021888118. [PMID: 33836595 PMCID: PMC7980373 DOI: 10.1073/pnas.2021888118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Protein aggregation is associated with a wide range of degenerative human diseases with devastating consequences, as exemplified by Alzheimer's, Parkinson's, and Huntington's diseases. In vitro kinetic studies have provided a mechanistic understanding of the aggregation process at the molecular level. However, it has so far remained largely unclear to what extent the biophysical principles of amyloid formation learned in vitro translate to the complex environment of living organisms. Here, we take advantage of the unique properties of a Caenorhabditis elegans model expressing a fluorescently tagged polyglutamine (polyQ) protein, which aggregates into discrete micrometer-sized inclusions that can be directly visualized in real time. We provide a quantitative analysis of protein aggregation in this system and show that the data are described by a molecular model where stochastic nucleation occurs independently in each cell, followed by rapid aggregate growth. Global fitting of the image-based aggregation kinetics reveals a nucleation rate corresponding to 0.01 h-1 per cell at 1 mM intracellular protein concentration, and shows that the intrinsic molecular stochasticity of nucleation accounts for a significant fraction of the observed animal-to-animal variation. Our results highlight how independent, stochastic nucleation events in individual cells control the overall progression of polyQ aggregation in a living animal. The key finding that the biophysical principles associated with protein aggregation in small volumes remain the governing factors, even in the complex environment of a living organism, will be critical for the interpretation of in vivo data from a wide range of protein aggregation diseases.
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26
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Minakawa EN, Nagai Y. Protein Aggregation Inhibitors as Disease-Modifying Therapies for Polyglutamine Diseases. Front Neurosci 2021; 15:621996. [PMID: 33642983 PMCID: PMC7907447 DOI: 10.3389/fnins.2021.621996] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/18/2021] [Indexed: 12/11/2022] Open
Abstract
The polyglutamine (polyQ) diseases are a group of inherited neurodegenerative diseases caused by the abnormal expansion of a CAG trinucleotide repeat that are translated into an expanded polyQ stretch in the disease-causative proteins. The expanded polyQ stretch itself plays a critical disease-causative role in the pathomechanisms underlying polyQ diseases. Notably, the expanded polyQ stretch undergoes a conformational transition from the native monomer into the β-sheet-rich monomer, followed by the formation of soluble oligomers and then insoluble aggregates with amyloid fibrillar structures. The intermediate soluble species including the β-sheet-rich monomer and oligomers exhibit substantial neurotoxicity. Therefore, protein conformation stabilization and aggregation inhibition that target the upstream of the insoluble aggregate formation would be a promising approach toward the development of disease-modifying therapies for polyQ diseases. PolyQ aggregation inhibitors of different chemical categories, such as intrabodies, peptides, and small chemical compounds, have been identified through intensive screening methods. Among them, recent advances in the brain delivery methods of several peptides and the screening of small chemical compounds have brought them closer to clinical utility. Notably, the recent discovery of arginine as a potent conformation stabilizer and aggregation inhibitor of polyQ proteins both in vitro and in vivo have paved way to the clinical trial for the patients with polyQ diseases. Meanwhile, expression reduction of expanded polyQ proteins per se would be another promising approach toward disease modification of polyQ diseases. Gene silencing, especially by antisense oligonucleotides (ASOs), have succeeded in reducing the expression of polyQ proteins in the animal models of various polyQ diseases by targeting the aberrant mRNA with expanded CAG repeats. Of note, some of these ASOs have recently been translated into clinical trials. Here we overview and discuss these recent advances toward the development of disease modifying therapies for polyQ diseases. We envision that combination therapies using aggregation inhibitors and gene silencing would meet the needs of the patients with polyQ diseases and their caregivers in the near future to delay or prevent the onset and progression of these currently intractable diseases.
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Affiliation(s)
- Eiko N Minakawa
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Yoshitaka Nagai
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan.,Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Japan
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27
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Siu HW, Heck B, Kovermann M, Hauser K. Template-assisted design of monomeric polyQ models to unravel the unique role of glutamine side chains in disease-related aggregation. Chem Sci 2020; 12:412-426. [PMID: 33552461 PMCID: PMC7863018 DOI: 10.1039/d0sc05299j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/28/2020] [Indexed: 01/28/2023] Open
Abstract
PolyQ model peptides reveal the effect of individual glutamine side chains on fibril formation.
Expanded polyglutamine (polyQ) sequences cause numerous neurodegenerative diseases which are accompanied by the formation of polyQ fibrils. The unique role of glutamines in the aggregation onset is undoubtedly accepted and a lot structural data of the fibrils have been acquired, however side-chain specific structural dynamics inducing oligomerization are not well understood yet. To analyze spectroscopically the nucleation process, we designed various template-assisted glutamine-rich β-hairpin monomers mimicking the structural motif of a polyQ fibril. In a top-down strategy, we use a template which forms a well-defined stable hairpin in solution, insert polyQ-rich sequences into each strand and monitor the effects of individual glutamines by NMR, CD and IR spectroscopic approaches. The design was further advanced by alternating glutamines with other amino acids (T, W, E, K), thereby enhancing the solubility and increasing the number of cross-strand interacting glutamine side chains. Our spectroscopic studies reveal a decreasing hairpin stability with increased glutamine content and demonstrate the enormous impact of only a few glutamines – far below the disease threshold – to destabilize structure. Furthermore, we could access sub-ms conformational dynamics of monomeric polyQ-rich peptides by laser-excited temperature-jump IR spectroscopy. Both, the increased number of interacting glutamines and higher concentrations are key parameters to induce oligomerization. Concentration-dependent time-resolved IR measurements indicate an additional slower kinetic phase upon oligomer formation. The here presented peptide models enable spectroscopic molecular analyses to distinguish between monomer and oligomer dynamics in the early steps of polyQ fibril formation and in a side-chain specific manner.
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Affiliation(s)
- Ho-Wah Siu
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
| | - Benjamin Heck
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
| | - Michael Kovermann
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
| | - Karin Hauser
- Department of Chemistry , University of Konstanz , 78457 Konstanz , Germany . ;
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28
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Investigating the effect of sugar-terminated nanoparticles on amyloid fibrillogenesis of β-lactoglobulin. Int J Biol Macromol 2020; 165:291-307. [PMID: 32961178 DOI: 10.1016/j.ijbiomac.2020.09.104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 08/19/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022]
Abstract
In vivo tissue deposition of fibrillar protein aggregates is the cause of several degenerative diseases. Evidence suggests that interfering with the pathology-associated amyloid fibrillogenesis by inhibitory molecules is envisaged as the primary therapeutic strategy. Amyloid fibril formation of proteins has been demonstrated to be influenced by nanoparticles/nanomaterials. As compared with their molecular form counterpart, this work examined the effect of sucrose-terminated nanoparticles on the in vitro amyloid fibrillogenesis and structural properties of β-lactoglobulin at pH 2.0 and 80 °C. ThT binding and electron microscopy results demonstrated that sucrose-terminated nanoparticles were able to suppress β-lactoglobulin fibrillogenesis in a concentration-dependent fashion. Importantly, sucrose-terminated nanoparticles showed better β-lactoglobulin fibril-inhibiting ability than sucrose molecules. ANS fluorescence and right-angle light scattering results showed reduced solvent exposure and decreased aggregation, respectively, in the β-lactoglobulin samples upon treatment with sucrose-terminated nanoparticles. Moreover, fluorescence quenching analyses revealed that the static quenching mechanism and formation of a non-fluorescent fluorophore-nanoparticle complex are involved in the nanoparticle-β-lactoglobulin interaction. We believe that the results from this study may suggest that the nanoparticle form of biocompatible sugar-related osmolytes may serve as effective inhibiting/suppressing agents toward protein fibrillogenesis.
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29
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Rosselli-Murai LK, Joseph JG, Lopes-Cendes I, Liu AP, Murai MJ. The Machado-Joseph disease-associated form of ataxin-3 impacts dynamics of clathrin-coated pits. Cell Biol Int 2020; 44:1252-1259. [PMID: 31970864 DOI: 10.1002/cbin.11312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 01/22/2020] [Indexed: 12/14/2022]
Abstract
Expansion above a certain threshold in the polyglutamine (polyQ) tract of ataxin-3 is the main cause of neurodegeneration in Machado-Joseph disease. Ataxin-3 contains an N-terminal catalytic domain, called Josephin domain, and a highly aggregation-prone C-terminal domain containing the polyQ tract. Recent work has shown that protein aggregation inhibits clathrin-mediated endocytosis (CME). However, the effects of polyQ expansion in ataxin-3 on CME have not been investigated. We hypothesize that the expansion of the polyQ tract in ataxin-3 could impact CME. Here, we report that both the wild-type and the expanded ataxin-3 reduce transferrin internalization and expanded ataxin-3 impacts dynamics of clathrin-coated pits (CCPs) by reducing CCP nucleation and increasing short-lived abortive CCPs. Since endocytosis plays a central role in regulating receptor uptake and cargo release, our work highlights a potential mechanism linking protein aggregation to cellular dysregulation.
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Affiliation(s)
- Luciana K Rosselli-Murai
- Department of Pharmacology, University of Michigan Medical School, 2301 MSRB III, 1150 W. Medical Center Dr., Ann Arbor, Michigan, 48109, USA.,Department of Mechanical Engineering, University of Michigan, 2674 GGB, 2350 Hayward, Ann Arbor, Michigan, 48109, USA
| | - Jophin G Joseph
- Department of Mechanical Engineering, University of Michigan, 2674 GGB, 2350 Hayward, Ann Arbor, Michigan, 48109, USA
| | - Iscia Lopes-Cendes
- Department of Medical Genetics, School of Medical Sciences, University of Campinas, R. Tessália Vieira de Camargo, 126, Campinas, São Paulo, 13083-970, Brazil.,The Brazilian Institute of Neuroscience and Neurotechnology, R. Vital Brasil, 251, Campinas, São Paulo, 13083-888, Brazil
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, 2674 GGB, 2350 Hayward, Ann Arbor, Michigan, 48109, USA
| | - Marcelo J Murai
- Department of Pharmacology, University of Michigan Medical School, 2301 MSRB III, 1150 W. Medical Center Dr., Ann Arbor, Michigan, 48109, USA.,Department of Medical Genetics, School of Medical Sciences, University of Campinas, R. Tessália Vieira de Camargo, 126, Campinas, São Paulo, 13083-970, Brazil
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30
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Moldovean SN, Chiş V. Molecular Dynamics Simulations Applied to Structural and Dynamical Transitions of the Huntingtin Protein: A Review. ACS Chem Neurosci 2020; 11:105-120. [PMID: 31841621 DOI: 10.1021/acschemneuro.9b00561] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Over the recent years, Huntington's disease (HD) has become widely discussed in the scientific literature especially because at the mutant level there are several contradictions regarding the aggregation mechanism. The specific role of the physiological huntingtin protein remains unknown, due to the lack of characterization of its entire crystallographic structure, making the experimental and theoretical research even harder when taking into consideration its involvement in multiple biological functions and its high affinity for different interacting partners. Different types of models, containing fewer (not more than 35 Qs) polyglutamine residues for the WT structure and above 35 Qs for the mutants, were subjected to classical or advanced MD simulations to establish the proteins' structural stability by evaluating their conformational changes. Outside the polyQ tract, there are two other regions of interest (the N17 domain and the polyP rich domain) considered to be essential for the aggregation kinetics at the mutant level. The polymerization process is considered to be dependent on the polyQ length. As the polyQ tract's dimension increases, the structures present more β-sheet conformations. Contrarily, it is also considered that the aggregation stability is not necessarily dependent on the number of Qs, while the initial stage of the aggregation seed might play the decisive role. A general assumption regarding the polyP domain is that it might preserve the polyQ structures soluble by acting as an antagonist for β-sheet formation.
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Affiliation(s)
| | - Vasile Chiş
- Babeş-Bolyai University, Faculty of Physics, Kogălniceanu 1, RO-400084 Cluj-Napoca, Romania
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31
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Escobedo A, Chiesa G, Salvatella X. Recombinant Production of Monomeric Isotope-Enriched Aggregation-Prone Peptides: Polyglutamine Tracts and Beyond. Methods Mol Biol 2020; 2141:211-231. [PMID: 32696359 DOI: 10.1007/978-1-0716-0524-0_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
High solvent exposure of certain sequences located in intrinsically disordered regions (IDRs) may eventually lead to aggregation, as is the case for some low-complexity regions (LCRs) and short linear motifs (SLiMs). In particular, polyglutamine (polyQ) tracts are LCRs of variable length highly enriched in glutamine residues. They are common in transcription factors, and their length can have an impact on transcriptional activity. In nine proteins, polyQ tract expansions beyond specific thresholds cause nine neurodegenerative diseases, and aggregates formed by the protein harboring the polyQ tract can be detected in affected individuals. A structural characterization of polyQ proteins in their monomeric form is key to understand how their expansion can affect their aggregation propensity. In this regard, nuclear magnetic resonance (NMR) spectroscopy can provide high-resolution structural information. Here, we present a protocol to prepare monomeric samples of isotope-enriched short helical polyQ peptides based on the sequence of the androgen receptor (AR) suitable for NMR characterization and suggest different ways to adapt it for the production and monomerization of other relatively short IDR sequences and SLiMs.
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Affiliation(s)
- Albert Escobedo
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Joint BSC-IRB Research Programme in Computational Biology, Barcelona, Spain
| | - Giulio Chiesa
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Joint BSC-IRB Research Programme in Computational Biology, Barcelona, Spain
- Department of Biomedical Engineering and Biological Design Center, Boston University, Boston, MA, USA
| | - Xavier Salvatella
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Joint BSC-IRB Research Programme in Computational Biology, Barcelona, Spain.
- ICREA, Barcelona, Spain.
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32
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Owen MC, Gnutt D, Gao M, Wärmländer SKTS, Jarvet J, Gräslund A, Winter R, Ebbinghaus S, Strodel B. Effects of in vivo conditions on amyloid aggregation. Chem Soc Rev 2019; 48:3946-3996. [PMID: 31192324 DOI: 10.1039/c8cs00034d] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the grand challenges of biophysical chemistry is to understand the principles that govern protein misfolding and aggregation, which is a highly complex process that is sensitive to initial conditions, operates on a huge range of length- and timescales, and has products that range from protein dimers to macroscopic amyloid fibrils. Aberrant aggregation is associated with more than 25 diseases, which include Alzheimer's, Parkinson's, Huntington's, and type II diabetes. Amyloid aggregation has been extensively studied in the test tube, therefore under conditions that are far from physiological relevance. Hence, there is dire need to extend these investigations to in vivo conditions where amyloid formation is affected by a myriad of biochemical interactions. As a hallmark of neurodegenerative diseases, these interactions need to be understood in detail to develop novel therapeutic interventions, as millions of people globally suffer from neurodegenerative disorders and type II diabetes. The aim of this review is to document the progress in the research on amyloid formation from a physicochemical perspective with a special focus on the physiological factors influencing the aggregation of the amyloid-β peptide, the islet amyloid polypeptide, α-synuclein, and the hungingtin protein.
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Affiliation(s)
- Michael C Owen
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - David Gnutt
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany and Lead Discovery Wuppertal, Bayer AG, 42096 Wuppertal, Germany
| | - Mimi Gao
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany and Sanofi-Aventis Deutschland GmbH, R&D, Industriepark Höchst, 65926 Frankfurt, Germany
| | - Sebastian K T S Wärmländer
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 42525 Jülich, Germany. and Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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33
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Laine RF, Sinnige T, Ma KY, Haack AJ, Poudel C, Gaida P, Curry N, Perni M, Nollen EA, Dobson CM, Vendruscolo M, Kaminski Schierle GS, Kaminski CF. Fast Fluorescence Lifetime Imaging Reveals the Aggregation Processes of α-Synuclein and Polyglutamine in Aging Caenorhabditis elegans. ACS Chem Biol 2019; 14:1628-1636. [PMID: 31246415 PMCID: PMC7612977 DOI: 10.1021/acschembio.9b00354] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The nematode worm Caenorhabditis elegans has emerged as an important model organism in the study of the molecular mechanisms of protein misfolding diseases associated with amyloid formation because of its small size, ease of genetic manipulation, and optical transparency. Obtaining a reliable and quantitative read-out of protein aggregation in this system, however, remains a challenge. To address this problem, we here present a fast time-gated fluorescence lifetime imaging (TG-FLIM) method and show that it provides functional insights into the process of protein aggregation in living animals by enabling the rapid characterization of different types of aggregates. Specifically, in longitudinal studies of C. elegans models of Parkinson's and Huntington's diseases, we observed marked differences in the aggregation kinetics and the nature of the protein inclusions formed by α-synuclein and polyglutamine. In particular, we found that α-synuclein inclusions do not display amyloid-like features until late in the life of the worms, whereas polyglutamine forms amyloid characteristics rapidly in early adulthood. Furthermore, we show that the TG-FLIM method is capable of imaging live and non-anaesthetized worms moving in specially designed agarose microchambers. Taken together, our results show that the TG-FLIM method enables high-throughput functional imaging of living C. elegans that can be used to study in vivo mechanisms of protein aggregation and that has the potential to aid the search for therapeutic modifiers of protein aggregation and toxicity.
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Affiliation(s)
- Romain F. Laine
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Tessa Sinnige
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Kai Yu Ma
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Amanda J. Haack
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
- Molecular Neuroscience Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Chetan Poudel
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Peter Gaida
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Nathan Curry
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Michele Perni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Ellen A.A. Nollen
- European Research Institute for the Biology of Ageing, University Medical Centre Groningen, 9700 AD Groningen, The Netherlands
| | - Christopher M. Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Gabriele S. Kaminski Schierle
- Molecular Neuroscience Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Clemens F. Kaminski
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
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Wahyuningtyas D, Chen WH, Huang CH, He YJ, Huang JJT. Biocompatible Inhibitor Based on Chitosan and Amphiphilic Peptide against Mutant Huntingtin Toxicity. Chembiochem 2019; 20:2133-2140. [PMID: 31166067 DOI: 10.1002/cbic.201900242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Indexed: 12/15/2022]
Abstract
Huntington's disease (HD) is classified as a protein-misfolding disease correlated with the mutant Huntingtin (mHtt) protein with abnormally expanded polyglutamine (polyQ) domains. Because no effective drugs have yet been reported, attempts to develop better therapy to delay the age of onset are in urgent demand. In this study, an amphiphilic peptide consisting of negatively charged hexaglutamic acid and a stretch of decaglutamine (E6 Q10 ) was chemically synthesized as an inhibitor against polyQ and mHtt toxicity. It is found that E6 Q10 selfassembles into spherical vesicles, as shown by means of TEM, cryoelectron microscopy, and dynamic light scattering. Assembled E6 Q10 prevented the polyQ-rich peptide (KKWQ20 AKK) from forming amyloid fibrils. To enable the cell-penetration ability of E6 Q10 , the E6 Q10 ⋅chitosan complex was generated. It is demonstrated that the complex penetrates cells, interferes with the mHtt oligomerization and aggregation process, and prevents mHtt cytotoxicity. By combining positively charged chitosan and amphiphilic peptides with a negatively charge moiety, a new strategy is provided to develop biocompatible and biodegradable inhibitors against mHtt toxicity.
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Affiliation(s)
- Devi Wahyuningtyas
- Institute of Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 115, Taiwan.,Sustainable Chemical Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 115, Taiwan.,Department of Applied Chemistry, National Chiao Tung University, Science Building 2, 1001 Ta Hsueh Road, Hsinchu, 300, Taiwan
| | - Wen-Hao Chen
- Institute of Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 115, Taiwan
| | - Chen-Han Huang
- Department of Biomedical Sciences and Engineering, National Central University, No. 300, Zhongda Road, Zhongli, Taoyuan, 32001, Taiwan
| | - Yu-Jung He
- Institute of Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 115, Taiwan
| | - Joseph Jen-Tse Huang
- Institute of Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 115, Taiwan
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35
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How SC, Hsin A, Chen GY, Hsu WT, Yang SM, Chou WL, Chou SH, Wang SSS. Exploring the influence of brilliant blue G on amyloid fibril formation of lysozyme. Int J Biol Macromol 2019; 138:37-48. [PMID: 31295491 DOI: 10.1016/j.ijbiomac.2019.07.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/28/2019] [Accepted: 07/07/2019] [Indexed: 12/19/2022]
Abstract
Evidence suggests that amyloid fibril mitigation/inhibition is considered a promising approach toward treating amyloid diseases. In this work, we first examined how amyloid fibrillogenesis of lysozyme was affected by BBG, a safe triphenylmethane compound with nice blood-brain-barrier-permeability, and found that shorter fibrillar species were formed in the lysozyme samples treated with BBG. Next, alterations in the features including the secondary as well as tertiary structure, extent of aggregation, and molecular distribution of lysozyme triggered by the addition of BBG were examined by various spectroscopic techniques, right-angle light scattering, dynamic light scattering, and SDS-PAGE. In addition, we have investigated how BBG affected the lysozyme fibril-induced cytotoxicity in SH-SY5Y cells. We found that a large quantity of shorter fibrillar species and more lysozyme monomers were present in the samples treated with BBG. Also, the addition of BBG rescued SH-SY5Y cells from cell death induced by amyloid fibrils of lysozyme. Finally, information about the binding sites and interacting forces involved in the BBG-lysozyme interaction was further explored using synchronous fluorescence and molecular docking approaches. Molecular docking results revealed that, apart from the hydrophobic interaction(s), hydrogen bonding, electrostatic interactions, and van der Waal forces may also be involved in the binding interaction.
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Affiliation(s)
- Su-Chun How
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Ai Hsin
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Guan-Yu Chen
- Department of Life Science, Fu-Jen Catholic University, Xinzhuang Dist., New Taipei City, Taiwan
| | - Wei-Tse Hsu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Szu-Ming Yang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Wei-Lung Chou
- Department of Safety, Health and Environmental Engineering, Hungkuang University, Sha Lu, Taichung City 433, Taiwan.
| | - Shiu-Huey Chou
- Department of Life Science, Fu-Jen Catholic University, Xinzhuang Dist., New Taipei City, Taiwan.
| | - Steven S-S Wang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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36
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Matlahov I, van der Wel PC. Conformational studies of pathogenic expanded polyglutamine protein deposits from Huntington's disease. Exp Biol Med (Maywood) 2019; 244:1584-1595. [PMID: 31203656 PMCID: PMC6920524 DOI: 10.1177/1535370219856620] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Huntington’s disease, like other neurodegenerative diseases, continues to lack an
effective cure. Current treatments that address early symptoms ultimately fail
Huntington’s disease patients and their families, with the disease typically
being fatal within 10–15 years from onset. Huntington’s disease is an inherited
disorder with motor and mental impairment, and is associated with the genetic
expansion of a CAG codon repeat encoding a polyglutamine-segment-containing
protein called huntingtin. These Huntington’s disease mutations cause misfolding
and aggregation of fragments of the mutant huntingtin protein, thereby likely
contributing to disease toxicity through a combination of gain-of-toxic-function
for the misfolded aggregates and a loss of function from sequestration of
huntingtin and other proteins. As with other amyloid diseases, the mutant
protein forms non-native fibrillar structures, which in Huntington’s disease are
found within patients’ neurons. The intracellular deposits are associated with
dysregulation of vital processes, and inter-neuronal transport of aggregates may
contribute to disease progression. However, a molecular understanding of these
aggregates and their detrimental effects has been frustrated by insufficient
structural data on the misfolded protein state. In this review, we examine
recent developments in the structural biology of polyglutamine-expanded
huntingtin fragments, and especially the contributions enabled by advances in
solid-state nuclear magnetic resonance spectroscopy. We summarize and discuss
our current structural understanding of the huntingtin deposits and how this
information furthers our understanding of the misfolding mechanism and disease
toxicity mechanisms.
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Affiliation(s)
- Irina Matlahov
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Patrick Ca van der Wel
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA.,Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747 AG, The Netherlands
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37
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Jansens KJA, Lambrecht MA, Rombouts I, Monge Morera M, Brijs K, Rousseau F, Schymkowitz J, Delcour JA. Conditions Governing Food Protein Amyloid Fibril Formation-Part I: Egg and Cereal Proteins. Compr Rev Food Sci Food Saf 2019; 18:1256-1276. [PMID: 33336994 DOI: 10.1111/1541-4337.12462] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/26/2019] [Accepted: 05/13/2019] [Indexed: 12/18/2022]
Abstract
Conditions including heating mode, time, temperature, pH, moisture and protein concentration, shear, and the presence of alcohols, chaotropic/reducing agents, enzymes, and/or salt influence amyloid fibril (AF) formation as they can affect the accessibility of amino acid sequences prone to aggregate. As some conditions applied on model protein resemble conditions in food processing unit operations, we here hypothesize that food processing can lead to formation of protein AFs with a compact cross β-sheet structure. This paper reviews conditions and food constituents that affect amyloid fibrillation of egg and cereal proteins. While egg and cereal proteins often coexist in food products, their impact on each other's fibrillation remains unknown. Hen egg ovalbumin and lysozyme form AFs when subjected to moderate heating at acidic pH separately. AFs can also be formed at higher pH, especially in the presence of alcohols or chaotropic/reducing agents. Tryptic wheat gluten digests can form fibrillar structures at neutral pH and maize and rice proteins do so in aqueous ethanol or at acidic pH, respectively.
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Affiliation(s)
- Koen J A Jansens
- KU Leuven, Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Kasteelpark Arenberg 20, B-3001, Leuven, Belgium.,Nutrex NV, Achterstenhoek 5, B-2275, Lille, Belgium
| | - Marlies A Lambrecht
- KU Leuven, Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Kasteelpark Arenberg 20, B-3001, Leuven, Belgium
| | - Ine Rombouts
- KU Leuven, Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Kasteelpark Arenberg 20, B-3001, Leuven, Belgium.,KU Leuven, ECOVO, Kasteelpark Arenberg 21, B-3001, Leuven, Belgium
| | - Margarita Monge Morera
- KU Leuven, Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Kasteelpark Arenberg 20, B-3001, Leuven, Belgium
| | - Kristof Brijs
- KU Leuven, Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Kasteelpark Arenberg 20, B-3001, Leuven, Belgium
| | - Frederic Rousseau
- Switch Laboratory, VIB, and Dept. of Cellular and Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium
| | - Joost Schymkowitz
- Switch Laboratory, VIB, and Dept. of Cellular and Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium
| | - Jan A Delcour
- KU Leuven, Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), Kasteelpark Arenberg 20, B-3001, Leuven, Belgium
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38
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Jakubek RS, Workman RJ, White SE, Asher SA. Polyglutamine Solution-State Structural Propensity Is Repeat Length Dependent. J Phys Chem B 2019; 123:4193-4203. [PMID: 31008597 DOI: 10.1021/acs.jpcb.9b01433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Expanded polyglutamine (polyQ) tracts in proteins, which are known to induce their aggregation, are associated with numerous neurodegenerative diseases. Longer polyQ tracts correlate with faster protein aggregation kinetics and a decreased age of onset for polyQ disease symptoms. Here, we use UV resonance Raman spectroscopy, circular dichroism spectroscopy, and metadynamics simulations to investigate the solution-state structures of the D2Q15K2 (Q15) and D2Q20K2 (Q20) peptides. Using metadynamics, we explore the conformational energy landscapes of Q15 and Q20 and investigate the relative energies and activation barriers between these low-energy structures. We compare the solution-state structures of D2Q10K2 (Q10), Q15, and Q20 to determine the dependence of polyQ structure on the Q tract length. We show that these peptides can adopt two distinct monomeric conformations: an aggregation-resistant PPII-like conformation and an aggregation-prone β-strand-like conformation. We find that longer polyQ peptides have an increased preference for the aggregation-prone β-strand-like conformation. This preference may play an important role in the increased aggregation rate of longer polyQ peptides that is thought to lead to decreased neurodegenerative disease age of onset for polyQ disease patients.
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Affiliation(s)
| | - Riley J Workman
- Department of Chemistry and Biochemistry, Center for Computational Sciences , Duquesne University , Pittsburgh , Pennsylvania 15282 , United States
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39
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Lu NH, How SC, Lin CY, Tsai SL, Bednarikova Z, Fedunova D, Gazova Z, Wu JW, Wang SSS. Examining the effects of dextran-based polymer-coated nanoparticles on amyloid fibrillogenesis of human insulin. Colloids Surf B Biointerfaces 2018; 172:674-683. [DOI: 10.1016/j.colsurfb.2018.09.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/24/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022]
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40
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Contessotto MG, Rosselli-Murai LK, Garcia MCC, Oliveira CL, Torriani IL, Lopes-Cendes I, Murai MJ. The Machado-Joseph disease-associated expanded form of ataxin-3: Overexpression, purification, and preliminary biophysical and structural characterization. Protein Expr Purif 2018; 152:40-45. [DOI: 10.1016/j.pep.2018.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 06/15/2018] [Accepted: 07/14/2018] [Indexed: 01/14/2023]
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41
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Pylaeva S, Böker A, Elgabarty H, Paul W, Sebastiani D. The Conformational Ensemble of Polyglutamine-14 Chains: Specific Influences of Solubility Tail and Chromophores. Chemphyschem 2018; 19:2931-2937. [PMID: 30106503 DOI: 10.1002/cphc.201800551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Indexed: 11/11/2022]
Abstract
We address polyglutamine-14 in aqueous solution with specific chromophores and a solubility chain by means of a multiscale simulation approach, combining atomistic molecular dynamics simulations and coarse-grained Monte-Carlo conformational sampling. Despite the intrinsically disordered nature of the amyloidogenic polyglutamine, we observe transient characteristic structural motifs which exhibit a specific hydrogen bonding pattern. We illustrate the relationship between structure pattern and the distance distribution of a pair of chromophores attached to the peptide termini, in light of specific influence of a short solubility tail and the chromophores themselves on the conformational ensemble.
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Affiliation(s)
- Svetlana Pylaeva
- Chemistry Department, MLU Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Arne Böker
- Physics Department, MLU Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Hossam Elgabarty
- Chemistry Department, MLU Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Wolfgang Paul
- Physics Department, MLU Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Daniel Sebastiani
- Chemistry Department, MLU Halle-Wittenberg, 06120, Halle (Saale), Germany
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42
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Burra G, Thakur AK. Insights into the molecular mechanism behind solubilization of amyloidogenic polyglutamine‐containing peptides. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24094] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Gunasekhar Burra
- Department of Biological Sciences and BioengineeringIndian Institute of Technology Kanpur Kanpur‐208016 India
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and BioengineeringIndian Institute of Technology Kanpur Kanpur‐208016 India
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43
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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: 8.0] [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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44
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Saha I, Singh V, Burra G, Thakur AK. Osmolytes modulate polyglutamine aggregation in a sequence dependent manner. J Pept Sci 2018; 24:e3115. [DOI: 10.1002/psc.3115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/18/2018] [Accepted: 06/22/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Itika Saha
- Department of Cellular Biochemistry; Max Planck Institute of Biochemistry; Martinsried Germany
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
| | - Virender Singh
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
| | - Gunasekhar Burra
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
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45
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Cox D, Raeburn C, Sui X, Hatters DM. Protein aggregation in cell biology: An aggregomics perspective of health and disease. Semin Cell Dev Biol 2018; 99:40-54. [PMID: 29753879 DOI: 10.1016/j.semcdb.2018.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/21/2018] [Accepted: 05/04/2018] [Indexed: 01/08/2023]
Abstract
Maintaining protein homeostasis (proteostasis) is essential for cellular health and is governed by a network of quality control machinery comprising over 800 genes. When proteostasis becomes imbalanced, proteins can abnormally aggregate or become mislocalized. Inappropriate protein aggregation and proteostasis imbalance are two of the central pathological features of common neurodegenerative diseases including Alzheimer, Parkinson, Huntington, and motor neuron diseases. How aggregation contributes to the pathogenic mechanisms of disease remains incompletely understood. Here, we integrate some of the key and emerging ideas as to how protein aggregation relates to imbalanced proteostasis with an emphasis on Huntington disease as our area of main expertise. We propose the term "aggregomics" be coined in reference to how aggregation of particular proteins concomitantly influences the spatial organization and protein-protein interactions of the surrounding proteome. Meta-analysis of aggregated interactomes from various published datasets reveals chaperones and RNA-binding proteins are common components across various disease contexts. We conclude with an examination of therapeutic avenues targeting proteostasis mechanisms.
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Affiliation(s)
- Dezerae Cox
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia
| | - Candice Raeburn
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia
| | - Xiaojing Sui
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia
| | - Danny M Hatters
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia.
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46
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Punihaole D, Jakubek RS, Workman RJ, Asher SA. Interaction Enthalpy of Side Chain and Backbone Amides in Polyglutamine Solution Monomers and Fibrils. J Phys Chem Lett 2018; 9:1944-1950. [PMID: 29570305 DOI: 10.1021/acs.jpclett.8b00348] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We determined an empirical correlation that relates the amide I vibrational band frequencies of the glutamine (Q) side chain to the strength of hydrogen bonding, van der Waals, and Lewis acid-base interactions of its primary amide carbonyl. We used this correlation to determine the Q side chain carbonyl interaction enthalpy (Δ Hint) in monomeric and amyloid-like fibril conformations of D2Q10K2 (Q10). We independently verified these Δ Hint values through molecular dynamics simulations that showed excellent agreement with experiments. We found that side chain-side chain and side chain-peptide backbone interactions in fibrils and monomers are more enthalpically favorable than are Q side chain-water interactions. Q10 fibrils also showed a more favorable Δ Hint for side chain-side chain interactions compared to backbone-backbone interactions. This work experimentally demonstrates that interamide side chain interactions are important in the formation and stabilization of polyQ fibrils.
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Affiliation(s)
- David Punihaole
- Department of Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Ryan S Jakubek
- Department of Chemistry , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
| | - Riley J Workman
- Department of Chemistry and Biochemistry , Center for Computational Sciences, Duquesne University , Pittsburgh , Pennsylvania 15282 , United States
| | - Sanford A Asher
- Department of Chemistry , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
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47
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Rai A, Singh PK, Singh V, Kumar V, Mishra R, Thakur AK, Mahadevan A, Shankar SK, Jana NR, Ganesh S. Glycogen synthase protects neurons from cytotoxicity of mutant huntingtin by enhancing the autophagy flux. Cell Death Dis 2018; 9:201. [PMID: 29422655 PMCID: PMC5833817 DOI: 10.1038/s41419-017-0190-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/22/2017] [Accepted: 11/24/2017] [Indexed: 12/11/2022]
Abstract
Healthy neurons do not store glycogen while they do possess the machinery for the glycogen synthesis albeit at an inactive state. Neurons in the degenerating brain, however, are known to accumulate glycogen, although its significance was not well understood. Emerging reports present contrasting views on neuronal glycogen synthesis; a few reports demonstrate a neurotoxic effect of glycogen while a few others suggest glycogen to be neuroprotective. Thus, the specific role of glycogen and glycogen synthase in neuronal physiology is largely unexplored. Using cellular and animal models of Huntington's disease, we show here that the overexpression of cytotoxic mutant huntingtin protein induces glycogen synthesis in the neurons by activating glycogen synthase and the overexpressed glycogen synthase protected neurons from the cytotoxicity of the mutant huntingtin. Exposure of neuronal cells to proteasomal blockade and oxidative stress also activate glycogen synthase to induce glycogen synthesis and to protect against stress-induced neuronal death. We show that the glycogen synthase plays an essential and inductive role in the neuronal autophagic flux, and helps in clearing the cytotoxic huntingtin aggregate. We also show that the increased neuronal glycogen inhibits the aggregation of mutant huntingtin, and thus could directly contribute to its clearance. Finally, we demonstrate that excessive autophagy flux is the molecular basis of cell death caused by the activation of glycogen synthase in unstressed neurons. Taken together, our results thus provide a novel function for glycogen synthase in proteolytic processes and offer insight into the role of glycogen synthase and glycogen in both survival and death of the neurons.
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Affiliation(s)
- Anupama Rai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Pankaj Kumar Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
- Institut de Génétique et de Biologie Moléculaire et Cellulare (IGBMC), Illkirch, France
| | - Virender Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | | | - Rohit Mishra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neuroscience, Bengaluru, 560029, India
| | - Susarla Krishna Shankar
- Department of Neuropathology, National Institute of Mental Health and Neuroscience, Bengaluru, 560029, India
| | | | - Subramaniam Ganesh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, India.
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48
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Pearce MMP, Kopito RR. Prion-Like Characteristics of Polyglutamine-Containing Proteins. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a024257. [PMID: 28096245 DOI: 10.1101/cshperspect.a024257] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transmissible spongiform encephalopathies are infectious neurodegenerative diseases caused by the conversion of prion protein (PrP) into a self-replicating conformation that spreads via templated conversion of natively folded PrP molecules within or between cells. Recent studies provide compelling evidence that prion-like behavior is a general property of most protein aggregates associated with neurodegenerative diseases. Many of these disorders are associated with spontaneous protein aggregation, but genetic mutations can increase the aggregation propensity of specific proteins, including expansion of polyglutamine (polyQ) tracts, which is causative of nine inherited neurodegenerative diseases. Aggregates formed by polyQ-expanded huntingtin (Htt) in Huntington's disease can transfer between cells and seed the aggregation of cytoplasmic wild-type Htt in a prion-like manner. Additionally, prion-like properties of glutamine-rich proteins underlie nonpathological processes in yeast and higher eukaryotes. Here, we review current evidence supporting prion-like characteristics of polyQ and glutamine-rich proteins.
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Affiliation(s)
- Margaret M P Pearce
- Department of Biological Sciences, University of the Sciences, Philadelphia, Pennsylvania 19104
| | - Ron R Kopito
- Department of Biology, Stanford University, Stanford, California 94305
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49
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Ghosh DK, Roy A, Ranjan A. Disordered Nanostructure in Huntingtin Interacting Protein K Acts as a Stabilizing Switch To Prevent Protein Aggregation. Biochemistry 2018; 57:2009-2023. [DOI: 10.1021/acs.biochem.7b00776] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Debasish Kumar Ghosh
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
- Graduate Studies, Manipal University, Manipal, Karnataka 576104, India
| | - Ajit Roy
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Akash Ranjan
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
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50
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Wetzel R, Chemuru S, Misra P, Kodali R, Mukherjee S, Kar K. An Aggregate Weight-Normalized Thioflavin-T Measurement Scale for Characterizing Polymorphic Amyloids and Assembly Intermediates. Methods Mol Biol 2018; 1777:121-144. [PMID: 29744831 DOI: 10.1007/978-1-4939-7811-3_6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The red shift in the fluorescence excitation spectra of thioflavin dyes upon binding to fibrils has been a boon to the amyloid field, offering simple and effective methods for the qualitative detection of amyloid in tissue samples and for quantitation of particular fibril preparations with gravimetric linearity. The quantitative aspect of the thioflavin T (ThT) response, however, comes with an important caveat that bestows both significant limitations and great untapped power. It is now well established that amyloid fibrils of different proteins, as well as polymorphic fibrils of the same protein, can exhibit vastly different ThT fluorescence intensities for the same weight concentration of aggregates. Furthermore, the aggregated intermediates commonly observed in amyloid assembly reactions can exhibit aggregate weight-normalized (AWN) ThT fluorescence intensities that vary from essentially zero through a wide range of intermediate values before reaching the intensity of homogeneous, mature amyloid. These features make it very difficult to quantitatively interpret, without additional data, the time-dependent development of ThT fluorescence intensity in an assembly reaction. In this chapter, we describe a method for coupling ex situ ThT fluorescence determinations with an analytical HPLC supported sedimentation assay (also described in detail) that can provide significant new insights into amyloid assembly reactions. The time dependent aggregation data provided by the sedimentation assay reveals a time course of aggregation that is largely independent of aggregate properties. In addition, the combination of these data with ThT measurements of the same reaction time points reveals important aspects of average aggregate structure at each time point. Examples of the use and potential value of AWN-ThT measurements during amyloid assembly Aβ and polyglutamine peptides are provided.
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Affiliation(s)
- Ronald Wetzel
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Saketh Chemuru
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Pinaki Misra
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Ravi Kodali
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, USA
| | - Smita Mukherjee
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- The Wharton School, University of Pennsylvania, Philadelphia, PA, USA
| | - Karunakar Kar
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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