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Babych M, Garelja ML, Nguyen PT, Hay DL, Bourgault S. Converting the Amyloidogenic Islet Amyloid Polypeptide into a Potent Nonaggregating Peptide Ligand by Side Chain-to-Side Chain Macrocyclization. J Am Chem Soc 2024; 146:25513-25526. [PMID: 39225636 DOI: 10.1021/jacs.4c05297] [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: 09/04/2024]
Abstract
The islet amyloid polypeptide (IAPP), also known as amylin, is a hormone playing key physiological roles. However, its aggregation and deposition in the pancreatic islets are associated with type 2 diabetes. While this peptide adopts mainly a random coil structure in solution, its secondary conformational conversion into α-helix represents a critical step for receptor activation and contributes to amyloid formation and associated cytotoxicity. Considering the large conformational landscape and high amyloidogenicity of the peptide, as well as the complexity of the self-assembly process, it is challenging to delineate the delicate interplay between helical folding, peptide aggregation, and receptor activation. In the present study, we probed the roles of helical folding on the function-toxicity duality of IAPP by restricting its conformational ensemble through side chain-to-side chain stapling via azide-alkyne cycloaddition. Intramolecular macrocyclization (i; i + 4) constrained IAPP into α-helix and inhibited its aggregation into amyloid fibrils. These helical derivatives slowed down the self-assembly of unmodified IAPP. Site-specific macrocyclization modulated the capacity of IAPP to perturb lipid bilayers and cell plasma membrane and reduced, or even fully inhibited, the cytotoxicity associated with aggregation. Furthermore, the α-helical IAPP analogs showed moderate to high potency toward cognate G protein-coupled receptors. Overall, these results indicate that macrocyclization represents a promising strategy to protect an amyloidogenic peptide hormone from aggregation and associated toxicity, while maintaining high receptor activity.
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Affiliation(s)
- Margaryta Babych
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal H3C 3P8, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, C.P. 8888, Succursale Centre-Ville, Montréal H3C 3P8, Canada
| | - Michael L Garelja
- Department of Pharmacology and Toxicology, University of Otago, 18 Frederick Street, Dunedin 9016, New Zealand
| | - Phuong Trang Nguyen
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal H3C 3P8, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, C.P. 8888, Succursale Centre-Ville, Montréal H3C 3P8, Canada
| | - Debbie L Hay
- Department of Pharmacology and Toxicology, University of Otago, 18 Frederick Street, Dunedin 9016, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, 3A Symonds Street, Auckland 92019, New Zealand
| | - Steve Bourgault
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal H3C 3P8, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, C.P. 8888, Succursale Centre-Ville, Montréal H3C 3P8, Canada
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Paul S, Mondal S, Shenogina I, Cui Q. The molecular basis for the increased stability of the FUS-LC fibril at the anionic membrane- and air-water interfaces. Chem Sci 2024; 15:13788-13799. [PMID: 39211498 PMCID: PMC11352777 DOI: 10.1039/d4sc02295e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/22/2024] [Indexed: 09/04/2024] Open
Abstract
Self-organization of biomolecules can lead to the formation of liquid droplets, hydrogels, and irreversible aggregates that bear immense significance in biology and diseases. Despite the considerable number of studies conducted on biomolecular condensation in bulk solution, there is still a lack of understanding of how different surfaces regulate the condensation process. In this context, recent studies showed that, in contrast to zwitterionic lipid membranes, anionic membranes promoted the production of liquid droplets of FUsed in Sarcoma Low Complexity domain (FUS-LC) despite exhibiting no specific protein-lipid interactions. Moreover, the air-water interface led to a solid fibril-like aggregate of FUS-LC. The molecular mechanism of condensation/aggregation of proteins in response to surfaces of various charged states or levels of hydrophobicity remains to be better elucidated. Here, we provide initial insights into this question by investigating the stability of a small β fibril state of FUS-LC in bulk solution vs. membrane- and air-water interfaces. We perform multiple independent molecular dynamics simulations with distinct starting conformations for each system to demonstrate the statistical significance of our findings. Our study demonstrates the stability of the FUS-LC fibril in the presence of anionic membranes on the μs timescale while the fibril falls apart in bulk solution. We observe that a zwitterionic membrane does not enhance the stability of the fibril and 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS) has a higher propensity to stabilize the fibril than dioleoylphosphatidylglycerol (DOPG), in qualitative agreement with experiments. We further show that the fibril becomes more stable at the air-water interface. We pinpoint interfacial solvation at the membrane- and air-water interfaces as a key factor that contributes to the stabilization of the peptide assembly.
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Affiliation(s)
- Sanjoy Paul
- Department of Chemistry, Boston University 590 Commonwealth Avenue Massachusetts-02215 USA
| | - Sayantan Mondal
- Department of Chemistry, Boston University 590 Commonwealth Avenue Massachusetts-02215 USA
| | - Irina Shenogina
- Department of Physics, University of Illinois Urbana-Champaign USA
| | - Qiang Cui
- Department of Chemistry, Boston University 590 Commonwealth Avenue Massachusetts-02215 USA
- Departments of Physics, and Biomedical Engineering, Boston University Massachusetts-02215 USA
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Akdag M, van Schijndel V, Sinnige T. Islet amyloid polypeptide tagged with green fluorescent protein localises to mitochondria and forms filamentous aggregates in Caenorhabditis elegans. Biophys Chem 2024; 307:107180. [PMID: 38241827 DOI: 10.1016/j.bpc.2024.107180] [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: 10/27/2023] [Revised: 12/22/2023] [Accepted: 01/12/2024] [Indexed: 01/21/2024]
Abstract
Type 2 diabetes (T2D) is the most common form of diabetes and represents a growing health concern. A characteristic feature of T2D is the aggregation of islet amyloid polypeptide (IAPP), which is thought to be associated with the death of pancreatic β-cells. Inhibiting IAPP aggregation is a promising therapeutic avenue to treat T2D, but the mechanisms of aggregation and toxicity are not yet fully understood. Caenorhabditis elegans is a well-characterised multicellular model organism that has been extensively used to study protein aggregation diseases. In this study, we aimed to develop a simple in vivo model to investigate IAPP aggregation and toxicity based on expression in the C. elegans body wall muscle cells. We show that IAPP tagged with green fluorescent protein (GFP) localises to mitochondria not only in muscle cells but also when expressed in the intestine, in line with previous observations in mouse and human pancreatic β-cells. The IAPP-GFP fusion protein forms solid aggregates, which have a filamentous appearance as seen by electron microscopy. However, the animals expressing IAPP-GFP in the body wall muscle cells do not display a strong motility phenotype, suggesting that the IAPP-GFP aggregates are not considerably toxic. Nevertheless, the mitochondrial localisation and aggregate formation may be useful read-outs to screen for IAPP-solubilizing compounds as a therapeutic strategy for T2D.
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Affiliation(s)
- Mehmet Akdag
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Vera van Schijndel
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Tessa Sinnige
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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Viles JH. Imaging Amyloid-β Membrane Interactions: Ion-Channel Pores and Lipid-Bilayer Permeability in Alzheimer's Disease. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202215785. [PMID: 38515735 PMCID: PMC10952214 DOI: 10.1002/ange.202215785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Indexed: 03/08/2023]
Abstract
The accumulation of the amyloid-β peptides (Aβ) is central to the development of Alzheimer's disease. The mechanism by which Aβ triggers a cascade of events that leads to dementia is a topic of intense investigation. Aβ self-associates into a series of complex assemblies with different structural and biophysical properties. It is the interaction of these oligomeric, protofibril and fibrillar assemblies with lipid membranes, or with membrane receptors, that results in membrane permeability and loss of cellular homeostasis, a key event in Alzheimer's disease pathology. Aβ can have an array of impacts on lipid membranes, reports have included: a carpeting effect; a detergent effect; and Aβ ion-channel pore formation. Recent advances imaging these interactions are providing a clearer picture of Aβ induced membrane disruption. Understanding the relationship between different Aβ structures and membrane permeability will inform therapeutics targeting Aβ cytotoxicity.
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Affiliation(s)
- John H. Viles
- Department of Biochemistry, SBBS, Queen MaryUniversity of LondonUK
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5
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Viles JH. Imaging Amyloid-β Membrane Interactions: Ion-Channel Pores and Lipid-Bilayer Permeability in Alzheimer's Disease. Angew Chem Int Ed Engl 2023; 62:e202215785. [PMID: 36876912 PMCID: PMC10953358 DOI: 10.1002/anie.202215785] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/07/2023]
Abstract
The accumulation of the amyloid-β peptides (Aβ) is central to the development of Alzheimer's disease. The mechanism by which Aβ triggers a cascade of events that leads to dementia is a topic of intense investigation. Aβ self-associates into a series of complex assemblies with different structural and biophysical properties. It is the interaction of these oligomeric, protofibril and fibrillar assemblies with lipid membranes, or with membrane receptors, that results in membrane permeability and loss of cellular homeostasis, a key event in Alzheimer's disease pathology. Aβ can have an array of impacts on lipid membranes, reports have included: a carpeting effect; a detergent effect; and Aβ ion-channel pore formation. Recent advances imaging these interactions are providing a clearer picture of Aβ induced membrane disruption. Understanding the relationship between different Aβ structures and membrane permeability will inform therapeutics targeting Aβ cytotoxicity.
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Affiliation(s)
- John H. Viles
- Department of Biochemistry, SBBS, Queen MaryUniversity of LondonUK
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Sanders HM, Chalyavi F, Fields CR, Kostelic MM, Li MH, Raleigh DP, Zanni MT, Marty MT. Interspecies Variation Affects Islet Amyloid Polypeptide Membrane Binding. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:986-990. [PMID: 37126782 PMCID: PMC10330443 DOI: 10.1021/jasms.3c00005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The aggregation of islet amyloid polypeptide (IAPP) is associated with β-cell dysfunction in type 2 diabetes (T2D) in humans. One possible mechanism of toxicity is the interaction of IAPP oligomers with lipid membranes to disrupt the bilayer integrity and/or homeostasis of the cell. Amino acid sequence variations of IAPPs between species can greatly decrease their propensity for aggregation. For example, human IAPP is toxic to β-cells, but rat and pig IAPP are not. However, it is not clear how these differences affect membrane association. Using native mass spectrometry with lipid nanodiscs, we explored the differences in the association of human, rat, and pig IAPP with lipid bilayers. We discovered that human and rat IAPP bound nanodiscs with anionic dipalmitoyl-phosphatidylglycerol (DPPG) lipids, but pig IAPP did not. Furthermore, human and rat IAPP interacted differently with the membrane. Human IAPP show potential tetramer complexes, but rat IAPP associated with the membrane sequentially. Thus, overall IAPP-bilayer interactions are not necessarily related to disease, but small differences in oligomeric behavior at the membrane may instead play a role.
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Affiliation(s)
- Henry M. Sanders
- Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
| | - Farzaneh Chalyavi
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Caitlyn R. Fields
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marius M. Kostelic
- Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
| | - Ming-Hao Li
- Department of Chemistry and Laufer Center for Quantitative Biology, Stony Brook University, 100 Nicolls Rd., Stony Brook, New York 11794, USA
| | - Daniel P. Raleigh
- Department of Chemistry and Laufer Center for Quantitative Biology, Stony Brook University, 100 Nicolls Rd., Stony Brook, New York 11794, USA
| | - Martin T. Zanni
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Michael T. Marty
- Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
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Elenbaas BO, Kremsreiter SM, Khemtemourian L, Killian JA, Sinnige T. Fibril elongation by human islet amyloid polypeptide is the main event linking aggregation to membrane damage. BBA ADVANCES 2023; 3:100083. [PMID: 37082256 PMCID: PMC10074975 DOI: 10.1016/j.bbadva.2023.100083] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The aggregation of human islet amyloid polypeptide (hIAPP) is linked to the death of pancreatic β-cells in type II diabetes. The process of fibril formation by hIAPP is thought to cause membrane damage, but the precise mechanisms are still unclear. Previously, we showed that the aggregation of hIAPP in the presence of membranes containing anionic lipids is dominated by secondary nucleation events, which occur at the interface between existing fibrils and the membrane surface. Here, we used vesicles with different lipid composition to explore the connection between hIAPP aggregation and vesicle leakage. We found that different anionic lipids promote hIAPP aggregation to the same extent, whereas remarkably stochastic behaviour is observed on purely zwitterionic membranes. Vesicle leakage induced by hIAPP consists of two distinct phases for any of the used membrane compositions: (i) an initial phase in which hIAPP binding causes a certain level of leakage that is strongly dependent on osmotic conditions, membrane composition and the used dye, and (ii) a main leakage event that we attribute to elongation of hIAPP fibrils, based on seeded experiments. Altogether, our results shed more light on the relationship between hIAPP fibril formation and membrane damage, and strongly suggest that oligomeric intermediates do not considerably contribute to vesicle leakage.
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Affiliation(s)
- Barend O.W. Elenbaas
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Stefanie M. Kremsreiter
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Lucie Khemtemourian
- Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN), CNRS UMR5248, University of Bordeaux, Bordeaux INP, allée Geoffroy St-Hilaire, 33600, Pessac, France
| | - J. Antoinette Killian
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Tessa Sinnige
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
- Corresponding author.
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