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Kalitnik A, Szefczyk M, Wojciechowska AW, Wojciechowski JW, Gąsior-Głogowska M, Olesiak-Bańska J, Kotulska M. Cytotoxic Staphylococcus aureus PSMα3 inhibits the aggregation of human insulin in vitro. Phys Chem Chem Phys 2024; 26:15587-15599. [PMID: 38757742 DOI: 10.1039/d4cp00669k] [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: 05/18/2024]
Abstract
Phenol-soluble modulins (PSMs) are extracellular short amphipathic peptides secreted by the bacteria Staphylococcus aureus (S. aureus). They play an essential role in the bacterial lifecycle, biofilm formation, and stabilisation. From the PSM family, PSMα3 has been of special interest recently due to its cytotoxicity and highly stable α-helical conformation, which also remains in its amyloid fibrils. In particular, PSMα3 fibrils were shown to be composed of self-associating "sheets" of α-helices oriented perpendicular to the fibril axis, mimicking the architecture of canonical cross-β fibrils. Therefore, they were called cross-α-fibrils. PSMα3 was synthesised and verified for identity with wild-type sequences (S. aureus). Then, using several experimental techniques, we evaluated its propensity for in vitro aggregation. According to our findings, synthetic PSMα3 (which lacks the N-terminal formyl groups found in bacteria) does not form amyloid fibrils and maintains α-helical conformation in a soluble monomeric form for several days of incubation. We also evaluated the influence of PSMα3 on human insulin fibrillation in vitro, using a variety of experimental approaches in combination with computational molecular studies. First, it was shown that PSMα3 drastically inhibits the fibrillation of human insulin. The anti-fibrillation effect of PSMα3 was concentration-dependent and required a concentration ratio of PSMα3: insulin equal to or above 1 : 100. Molecular modelling revealed that PSMα3 most likely inhibits the production of insulin primary nuclei by competing for residues involved in its dimerization.
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Affiliation(s)
- Aleksandra Kalitnik
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
| | - Monika Szefczyk
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Alicja W Wojciechowska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
| | - Jakub W Wojciechowski
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
| | - Marlena Gąsior-Głogowska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
| | - Joanna Olesiak-Bańska
- Institute of Advanced Materials, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Małgorzata Kotulska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
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2
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Chen A, Shea D, Daggett V. Performance of SOBA-AD blood test in discriminating Alzheimer's disease patients from cognitively unimpaired controls in two independent cohorts. Sci Rep 2024; 14:7946. [PMID: 38575622 PMCID: PMC10995183 DOI: 10.1038/s41598-024-57107-w] [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: 01/02/2024] [Accepted: 03/14/2024] [Indexed: 04/06/2024] Open
Abstract
Amyloid-beta (Aβ) toxic oligomers are critical early players in the molecular pathology of Alzheimer's disease (AD). We have developed a Soluble Oligomer Binding Assay (SOBA-AD) for detection of these Aβ oligomers that contain α-sheet secondary structure that discriminates plasma samples from patients on the AD continuum from non-AD controls. We tested 265 plasma samples from two independent cohorts to investigate the performance of SOBA-AD. Testing was performed at two different sites, with different personnel, reagents, and instrumentation. Across two cohorts, SOBA-AD discriminated AD patients from cognitively unimpaired (CU) subjects with 100% sensitivity, > 95% specificity, and > 98% area under the curve (AUC) (95% CI 0.95-1.00). A SOBA-AD positive readout, reflecting α-sheet toxic oligomer burden, was found in AD patients, and not in controls, providing separation of the two populations, aside from 5 SOBA-AD positive controls. Based on an earlier SOBA-AD study, the Aβ oligomers detected in these CU subjects may represent preclinical cases of AD. The results presented here support the value of SOBA-AD as a promising blood-based tool for the detection and confirmation of AD.
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Affiliation(s)
- Amy Chen
- AltPep Corporation, 1150 Eastlake Avenue N, Suite 800, Seattle, WA, 98109, USA
| | - Dylan Shea
- AltPep Corporation, 1150 Eastlake Avenue N, Suite 800, Seattle, WA, 98109, USA
- University of Washington, Box 355610, Seattle, WA, 98195-5610, USA
| | - Valerie Daggett
- AltPep Corporation, 1150 Eastlake Avenue N, Suite 800, Seattle, WA, 98109, USA.
- University of Washington, Box 355610, Seattle, WA, 98195-5610, USA.
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3
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De Maeseneer T, Cauwenbergh T, Gardiner J, White JF, Thielemans W, Martin C, Moldenaers P, Ballet S, Cardinaels R. Peptide Sequence Variations Govern Hydrogel Stiffness: Insights from a Multi-Scale Structural Analysis of H-FQFQFK-NH 2 Peptide Derivatives. Macromol Biosci 2024:e2300579. [PMID: 38552257 DOI: 10.1002/mabi.202300579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/14/2024] [Indexed: 04/26/2024]
Abstract
Throughout the past decades, amphipathic peptide-based hydrogels have proven to be promising materials for biomedical applications. Amphipathic peptides are known to adopt β-sheet configurations that self-assemble into fibers that then interact to form a hydrogel network. A fundamental understanding of how the peptide sequence alters the structural properties of the hydrogels would allow for a more rational design of novel peptides for a variety of biomedical applications in the future. Therefore, the current work investigates how changing the type of amino acid, the amphipathic pattern, and the peptide length affects the secondary structure, fiber characteristics, and stiffness of peptide-based hydrogels. Hereto, seven amphipathic peptides of different sequence and length, four of which have not been previously reported, based on and including the hexapeptide H-Phe-Gln-Phe-Gln-Phe-Lys-NH2, are synthesized and thoroughly characterized by circular dichroism (CD), Fourier Transform Infrared (FTIR) spectroscopy, Wide Angle X-ray Scattering (WAXS), Small Angle X-ray Scattering (SAXS), Transmission Electron Microscopy (TEM), and Thioflavin T (ThT) fibrillization assays. The results show that a high amount of regularly spaced β-sheets, a high amount of fibers, and fiber bundling contribute to the stiffness of the hydrogel. Furthermore, a study of the time-dependent fibril formation process reveals complex transient dynamics. The peptide strands structure through an intermediate helical state prior to β-sheet formation, which is found to be concentration- and time-dependent.
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Affiliation(s)
- Tess De Maeseneer
- Soft Matter, Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J, Box 2424, Leuven, 3001, Belgium
| | - Thibault Cauwenbergh
- Research Group of Organic Chemistry, Department of Chemistry, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - James Gardiner
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3169, Australia
| | - Jacinta F White
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3169, Australia
| | - Wim Thielemans
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, campus Kulak Kortrijk, Etienne Sabbelaan 53, Kortrijk, 8500, Belgium
| | - Charlotte Martin
- Research Group of Organic Chemistry, Department of Chemistry, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Paula Moldenaers
- Soft Matter, Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J, Box 2424, Leuven, 3001, Belgium
| | - Steven Ballet
- Research Group of Organic Chemistry, Department of Chemistry, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Ruth Cardinaels
- Soft Matter, Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J, Box 2424, Leuven, 3001, Belgium
- Processing and Performance of Materials, Department of Mechanical Engineering, TU Eindhoven, P.O. Box 513, Eindhoven, 5600 MB, The Netherlands
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4
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Prosswimmer T, Heng A, Daggett V. Mechanistic insights into the role of amyloid-β in innate immunity. Sci Rep 2024; 14:5376. [PMID: 38438446 PMCID: PMC10912764 DOI: 10.1038/s41598-024-55423-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/23/2024] [Indexed: 03/06/2024] Open
Abstract
Colocalization of microbial pathogens and the β-amyloid peptide (Aβ) in the brain of Alzheimer's disease (AD) patients suggests that microbial infection may play a role in sporadic AD. Aβ exhibits antimicrobial activity against numerous pathogens, supporting a potential role for Aβ in the innate immune response. While mammalian amyloid is associated with disease, many bacteria form amyloid fibrils to fortify the biofilm that protects the cells from the surrounding environment. In the microbial AD hypothesis, Aβ aggregates in response to infection to combat the pathogen. We hypothesize that this occurs through toxic Aβ oligomers that contain α-sheet structure and form prior to fibrillization. De novo designed α-sheet peptides specifically bind to the α-sheet structure present in the oligomers of both bacterial and mammalian amyloidogenic proteins to neutralize toxicity and inhibit aggregation. Here, we measure the effect of E. coli on Aβ, including upregulation, aggregation, and toxicity. Additionally, we determined the effect of Aβ structure on E. coli amyloid fibrils, or curli comprised of the CsgA protein, and biofilm formation. We found that curli formation by E. coli increased Aβ oligomer production, and Aβ oligomers inhibited curli biogenesis and reduced biofilm cell density. Further, curli and biofilm inhibition by Aβ oligomers increased E. coli susceptibility to gentamicin. Toxic oligomers of Aβ and CsgA interact via α-sheet interactions, neutralizing their toxicity. These results suggest that exposure to toxic oligomers formed by microbial pathogens triggers Aβ oligomer upregulation and aggregation to combat infection via selective interactions between α-sheet oligomers to neutralize toxicity of both species with subsequent inhibition of fibrillization.
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Affiliation(s)
- Tatum Prosswimmer
- Molecular Engineering Program, University of Washington, Seattle, WA, 98195-5610, USA
| | - Anthony Heng
- Department of Neuroscience, University of Washington, Seattle, WA, 98195-5610, USA
- Department of Biochemistry, University of Washington, Seattle, WA, 98195-5610, USA
| | - Valerie Daggett
- Molecular Engineering Program, University of Washington, Seattle, WA, 98195-5610, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, 98195-5610, USA.
- Department of Bioengineering, University of Washington, Seattle, WA, 98195-5610, USA.
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5
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Hsu C, Templin AT, Prosswimmer T, Shea D, Li J, Brooks‐Worrell B, Kahn SE, Daggett V. Human islet amyloid polypeptide-induced β-cell cytotoxicity is linked to formation of α-sheet structure. Protein Sci 2024; 33:e4854. [PMID: 38062941 PMCID: PMC10823758 DOI: 10.1002/pro.4854] [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: 06/06/2023] [Revised: 11/10/2023] [Accepted: 12/04/2023] [Indexed: 01/30/2024]
Abstract
Type 2 diabetes (T2D) results from insulin secretory dysfunction arising in part from the loss of pancreatic islet β-cells. Several factors contribute to β-cell loss, including islet amyloid formation, which is observed in over 90% of individuals with T2D. The amyloid is comprised of human islet amyloid polypeptide (hIAPP). Here we provide evidence that early in aggregation, hIAPP forms toxic oligomers prior to formation of amyloid fibrils. The toxic oligomers contain α-sheet secondary structure, a nonstandard secondary structure associated with toxic oligomers in other amyloid diseases. De novo, synthetic α-sheet compounds designed to be nontoxic and complementary to the α-sheet structure in the toxic oligomers inhibit hIAPP aggregation and neutralize oligomer-mediated cytotoxicity in cell-based assays. In vivo administration of an α-sheet design to mice for 4 weeks revealed no evidence of toxicity nor did it elicit an immune response. Furthermore, the α-sheet designs reduced endogenous islet amyloid formation and mitigation of amyloid-associated β-cell loss in cultured islets isolated from an hIAPP transgenic mouse model of islet amyloidosis. Characterization of the involvement of α-sheet in early aggregation of hIAPP and oligomer toxicity contributes to elucidation of the molecular mechanisms underlying amyloid-associated β-cell loss.
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Affiliation(s)
- Cheng‐Chieh Hsu
- Department of BioengineeringUniversity of WashingtonSeattleWashingtonUSA
- Molecular Engineering ProgramUniversity of WashingtonSeattleWashingtonUSA
| | - Andrew T. Templin
- Division of Metabolism, Endocrinology and Nutrition, Department of MedicineVA Puget Sound Health Care System and University of WashingtonSeattleWashingtonUSA
| | - Tatum Prosswimmer
- Molecular Engineering ProgramUniversity of WashingtonSeattleWashingtonUSA
| | - Dylan Shea
- Molecular Engineering ProgramUniversity of WashingtonSeattleWashingtonUSA
| | - Jinzheng Li
- Department of BiochemistryUniversity of WashingtonSeattleWashingtonUSA
| | - Barbara Brooks‐Worrell
- Division of Metabolism, Endocrinology and Nutrition, Department of MedicineVA Puget Sound Health Care System and University of WashingtonSeattleWashingtonUSA
| | - Steven E. Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of MedicineVA Puget Sound Health Care System and University of WashingtonSeattleWashingtonUSA
| | - Valerie Daggett
- Department of BioengineeringUniversity of WashingtonSeattleWashingtonUSA
- Molecular Engineering ProgramUniversity of WashingtonSeattleWashingtonUSA
- Department of BiochemistryUniversity of WashingtonSeattleWashingtonUSA
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6
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Han YL, Yin HH, Xiao C, Bernards MT, He Y, Guan YX. Understanding the Molecular Mechanisms of Polyphenol Inhibition of Amyloid β Aggregation. ACS Chem Neurosci 2023; 14:4051-4061. [PMID: 37890131 DOI: 10.1021/acschemneuro.3c00586] [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: 10/29/2023] Open
Abstract
Alzheimer's disease (AD) is highly associated with self-aggregation of amyloid β (Aβ) proteins into fibrils. Inhibition of Aβ aggregation by polyphenols is one of the major therapeutic strategies for AD. Among them, four polyphenols (brazilin, resveratrol, hematoxylin, and rosmarinic acid) have been reported to be effective at inhibiting Aβ aggregation, but the inhibition mechanisms are still unclear. In this work, these four polyphenols were selected to explore their interactions with the Aβ17-42 pentamer by molecular dynamics simulation. All four polyphenols can bind to the pentamer tightly but prefer different binding sites. Conversion of the β-sheet to the random coil, fewer interchain hydrogen bonds, and weaker salt bridges were observed after binding. Interestingly, different Aβ17-42 pentamer destabilizing mechanisms for resveratrol and hematoxylin were found. Resveratrol inserts into the hydrophobic core of the pentamer by forming hydrogen bonds with Asp23 and Lys28, while hematoxylin prefers to bind beside chain A of the pentamer, which leads to β-sheet offset and dissociation of the β1 sheet of chain E. This work reveals the interactions between the Aβ17-42 pentamer and four polyphenols and discusses the relationship between inhibitor structures and their inhibition mechanisms, which also provides useful guidance for screening effective Aβ aggregation inhibitors and drug design against AD.
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Affiliation(s)
- Yin-Lei Han
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
| | - Huan-Huan Yin
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
| | - Chao Xiao
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
| | - Matthew T Bernards
- Department of Chemical and Biological Engineering, University of Idaho, Moscow 83844, Idaho, United States
| | - Yi He
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
- Department of Chemical Engineering, University of Washington, Seattle 98195, Washington, United States
| | - Yi-Xin Guan
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
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7
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Wang C, Shao S, Li N, Zhang Z, Zhang H, Liu B. Advances in Alzheimer's Disease-Associated Aβ Therapy Based on Peptide. Int J Mol Sci 2023; 24:13110. [PMID: 37685916 PMCID: PMC10487952 DOI: 10.3390/ijms241713110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/11/2023] [Accepted: 08/19/2023] [Indexed: 09/10/2023] Open
Abstract
Alzheimer's disease (AD) urgently needs innovative treatments due to the increasing aging population and lack of effective drugs and therapies. The amyloid fibrosis of AD-associated β-amyloid (Aβ) that could induce a series of cascades, such as oxidative stress and inflammation, is a critical factor in the progression of AD. Recently, peptide-based therapies for AD are expected to be great potential strategies for the high specificity to the targets, low toxicity, fast blood clearance, rapid cell and tissue permeability, and superior biochemical characteristics. Specifically, various chiral amino acids or peptide-modified interfaces draw much attention as effective manners to inhibit Aβ fibrillation. On the other hand, peptide-based inhibitors could be obtained through affinity screening such as phage display or by rational design based on the core sequence of Aβ fibrosis or by computer aided drug design based on the structure of Aβ. These peptide-based therapies can inhibit Aβ fibrillation and reduce cytotoxicity induced by Aβ aggregation and some have been shown to relieve cognition in AD model mice and reduce Aβ plaques in mice brains. This review summarizes the design method and characteristics of peptide inhibitors and their effect on the amyloid fibrosis of Aβ. We further describe some analysis methods for evaluating the inhibitory effect and point out the challenges in these areas, and possible directions for the design of AD drugs based on peptides, which lay the foundation for the development of new effective drugs in the future.
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Affiliation(s)
- Cunli Wang
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Lingshui Road, Dalian 116024, China; (C.W.); (S.S.); (N.L.); (Z.Z.); (H.Z.)
| | - Shuai Shao
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Lingshui Road, Dalian 116024, China; (C.W.); (S.S.); (N.L.); (Z.Z.); (H.Z.)
- Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Na Li
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Lingshui Road, Dalian 116024, China; (C.W.); (S.S.); (N.L.); (Z.Z.); (H.Z.)
- Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Zhengyao Zhang
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Lingshui Road, Dalian 116024, China; (C.W.); (S.S.); (N.L.); (Z.Z.); (H.Z.)
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin 124221, China
| | - Hangyu Zhang
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Lingshui Road, Dalian 116024, China; (C.W.); (S.S.); (N.L.); (Z.Z.); (H.Z.)
- Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Bo Liu
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Lingshui Road, Dalian 116024, China; (C.W.); (S.S.); (N.L.); (Z.Z.); (H.Z.)
- Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
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8
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Sheikh A, Mughal S, Owais R, Siddiqui MS. SOBA (soluble oligomer binding assay): A breakthrough or the early diagnosis of Alzheimer's disease. Health Sci Rep 2023; 6:e1492. [PMID: 37599661 PMCID: PMC10435830 DOI: 10.1002/hsr2.1492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/05/2023] [Accepted: 08/01/2023] [Indexed: 08/22/2023] Open
Affiliation(s)
- Ayesha Sheikh
- Department of MedicineDow University of Health SciencesKarachiPakistan
| | - Sanila Mughal
- Department of MedicineDow University of Health SciencesKarachiPakistan
| | - Rabia Owais
- Department of MedicineDow University of Health SciencesKarachiPakistan
| | - Mishal Shan Siddiqui
- Department of Surgery. Dr. Ruth K. M. Pfau, Civil Hospital KarachiDow University of Health SciencesKarachiPakistan
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9
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Bleem A, Prosswimmer T, Chen R, Hady TF, Li J, Bryers JD, Daggett V. Designed α-sheet peptides disrupt uropathogenic E. coli biofilms rendering bacteria susceptible to antibiotics and immune cells. Sci Rep 2023; 13:9272. [PMID: 37286572 PMCID: PMC10247742 DOI: 10.1038/s41598-023-36343-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 06/01/2023] [Indexed: 06/09/2023] Open
Abstract
Uropathogenic Escherichia coli account for the largest proportion of nosocomial infections in the United States. Nosocomial infections are a major source of increased costs and treatment complications. Many infections are biofilm associated, rendering antibiotic treatments ineffective or cause additional complications (e.g., microbiome depletion). This work presents a potentially complementary non-antibiotic strategy to fight nosocomial infections by inhibiting the formation of amyloid fibrils, a proteinaceous structural reinforcement known as curli in E. coli biofilms. Despite extensive characterization of the fibrils themselves and their associated secretion system, mechanistic details of curli assembly in vivo remain unclear. We hypothesized that, like other amyloid fibrils, curli polymerization involves a unique secondary structure termed "α-sheet". Biophysical studies herein confirmed the presence of α-sheet structure in prefibrillar species of CsgA, the major component of curli, as it aggregated. Binding of synthetic α-sheet peptides to the soluble α-sheet prefibrillar species inhibited CsgA aggregation in vitro and suppressed amyloid fibril formation in biofilms. Application of synthetic α-sheet peptides also enhanced antibiotic susceptibility and dispersed biofilm-resident bacteria for improved uptake by phagocytic cells. The ability of synthetic α-sheet peptides to reduce biofilm formation, improve antibiotic susceptibility, and enhance clearance by macrophages has broad implications for combating biofilm-associated infections.
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Affiliation(s)
- Alissa Bleem
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Tatum Prosswimmer
- Molecular Engineering Program, University of Washington, Seattle, WA, 98195, USA
| | - Ruying Chen
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
- Department of Surgery and Center for Lung Biology, University of Washington, Seattle, WA, 98109, USA
| | - Thomas F Hady
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Jinzheng Li
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - James D Bryers
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
- Department of Surgery and Center for Lung Biology, University of Washington, Seattle, WA, 98109, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA.
- Molecular Engineering Program, University of Washington, Seattle, WA, 98195, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA.
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10
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Indig RY, Landau M. Designed inhibitors to reduce amyloid virulence and cytotoxicity and combat neurodegenerative and infectious diseases. Curr Opin Chem Biol 2023; 75:102318. [PMID: 37196450 DOI: 10.1016/j.cbpa.2023.102318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 04/10/2023] [Accepted: 04/14/2023] [Indexed: 05/19/2023]
Abstract
The review highlights the role of amyloids in various diseases and the challenges associated with targeting human amyloids in therapeutic development. However, due to the better understanding of microbial amyloids' role as virulence factors, there is a growing interest in repurposing and designing anti-amyloid compounds for antivirulence therapy. The identification of amyloid inhibitors has not only significant clinical implications but also provides valuable insights into the structure and function of amyloids. The review showcases small molecules and peptides that specifically target amyloids in both humans and microbes, reducing cytotoxicity and biofilm formation, respectively. The review emphasizes the importance of further research on amyloid structures, mechanisms, and interactions across all life forms to yield new drug targets and improve the design of selective treatments. Overall, the review highlights the potential for amyloid inhibitors in therapeutic development for both human diseases and microbial infections.
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Affiliation(s)
- Rinat Yona Indig
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel; Centre for Structural Systems Biology (CSSB) and Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany; European Molecular Biology Laboratory (EMBL), Hamburg, Germany.
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11
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Ghosh S, Ali R, Verma S. Aβ-oligomers: A potential therapeutic target for Alzheimer's disease. Int J Biol Macromol 2023; 239:124231. [PMID: 36996958 DOI: 10.1016/j.ijbiomac.2023.124231] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/22/2023] [Accepted: 03/25/2023] [Indexed: 03/30/2023]
Abstract
The cascade of amyloid formation relates to multiple complex events at the molecular level. Previous research has established amyloid plaque deposition as the leading cause of Alzheimer's disease (AD) pathogenesis, detected mainly in aged population. The primary components of the plaques are two alloforms of amyloid-beta (Aβ), Aβ1-42 and Aβ1-40 peptides. Recent studies have provided considerable evidence contrary to the previous claim indicating that amyloid-beta oligomers (AβOs) as the main culprit responsible for AD-associated neurotoxicity and pathogenesis. In this review, we have discussed the primary features of AβOs, such as assembly formation, the kinetics of oligomer formation, interactions with various membranes/membrane receptors, the origin of toxicity, and oligomer-specific detection methods. Recently, the discovery of rationally designed antibodies has opened a gateway for using synthesized peptides as a grafting component in the complementarity determining region (CDR) of antibodies. Thus, the Aβ sequence motif or the complementary peptide sequence in the opposite strand of the β-sheet (extracted from the Protein Data Bank: PDB) helps design oligomer-specific inhibitors. The microscopic event responsible for oligomer formation can be targeted, and thus prevention of the overall macroscopic behaviour of the aggregation or the associated toxicity can be achieved. We have carefully reviewed the oligomer formation kinetics and associated parameters. Besides, we have depicted a thorough understanding of how the synthesized peptide inhibitors can impede the early aggregates (oligomers), mature fibrils, monomers, or a mixture of the species. The oligomer-specific inhibitors (peptides or peptide fragments) lack in-depth chemical kinetics and optimization control-based screening. In the present review, we have proposed a hypothesis for effectively screening oligomer-specific inhibitors using the chemical kinetics (determining the kinetic parameters) and optimization control strategy (cost-dependent analysis). Further, it may be possible to implement the structure-kinetic-activity-relationship (SKAR) strategy instead of structure-activity-relationship (SAR) to improve the inhibitor's activity. The controlled optimization of the kinetic parameters and dose usage will be beneficial for narrowing the search window for the inhibitors.
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12
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SOBA: Development and testing of a soluble oligomer binding assay for detection of amyloidogenic toxic oligomers. Proc Natl Acad Sci U S A 2022; 119:e2213157119. [PMID: 36490316 PMCID: PMC9897489 DOI: 10.1073/pnas.2213157119] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The formation of toxic Amyloid β-peptide (Aβ) oligomers is one of the earliest events in the molecular pathology of Alzheimer's Disease (AD). These oligomers lead to a variety of downstream effects, including impaired neuronal signaling, neuroinflammation, tau phosphorylation, and neurodegeneration, and it is estimated that these events begin 10 to 20 y before the presentation of symptoms. Toxic Aβ oligomers contain a nonstandard protein structure, termed α-sheet, and designed α-sheet peptides target this main-chain structure in toxic oligomers independent of sequence. Here we show that a designed α-sheet peptide inhibits the deleterious effects on neuronal signaling and also serves as a capture agent in our soluble oligomer binding assay (SOBA). Pre-incubated synthetic α-sheet-containing Aβ oligomers produce strong SOBA signals, while monomeric and β-sheet protofibrillar Aβ do not. α-sheet containing oligomers were also present in cerebrospinal fluid (CSF) from an AD patient versus a noncognitively impaired control. For the detection of toxic oligomers in plasma, we developed a plate coating to increase the density of the capture peptide. The proof of concept was achieved by testing 379 banked human plasma samples. SOBA detected Aβ oligomers in patients on the AD continuum, including controls who later progressed to mild cognitive impairment. In addition, SOBA discriminated AD from other forms of dementia, yielding sensitivity and specificity of 99% relative to clinical and neuropathological diagnoses. To explore the broader potential of SOBA, we adapted the assay for a-synuclein oligomers and confirmed their presence in CSF from patients with Parkinson's disease and Lewy body dementia.
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13
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Zhou P, Hu X, Li J, Wang Y, Yu H, Chen Z, Wang D, Zhao Y, King SM, Rogers SE, Wang J, Lu JR, Xu H. Peptide Self-Assemblies from Unusual α-Sheet Conformations Based on Alternation of d/ l Amino Acids. J Am Chem Soc 2022; 144:21544-21554. [DOI: 10.1021/jacs.2c08425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Peng Zhou
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Xuzhi Hu
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, U.K
| | - Jie Li
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Yan Wang
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Henghao Yu
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Zhaoyu Chen
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Dong Wang
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Yurong Zhao
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Stephen M. King
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, U.K
| | - Sarah E. Rogers
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, U.K
| | - Jiqian Wang
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Jian Ren Lu
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, U.K
| | - Hai Xu
- State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
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14
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Prosswimmer T, Daggett V. The role of α-sheet structure in amyloidogenesis: characterization and implications. Open Biol 2022; 12:220261. [PMID: 36416010 PMCID: PMC9682440 DOI: 10.1098/rsob.220261] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Amyloid diseases are linked to protein misfolding whereby the amyloidogenic protein undergoes a conformational change, aggregates and eventually forms amyloid fibrils. While the amyloid fibrils and plaques are hallmarks of these diseases, they typically form late in the disease process and do not correlate with disease. Instead, there is growing evidence that smaller, soluble toxic oligomers form prior and appear to be early triggers of the molecular pathology underlying these diseases. Nearly 20 years ago, we proposed the α-sheet hypothesis after discovering that the early conformational changes observed during atomistic molecular dynamics simulations involve the formation of a non-standard protein structure, α-sheet. Furthermore, we proposed that toxic oligomers contain α-sheet structure and that preferentially targeting this structure could neutralize the toxicity, prevent further aggregation and serve as the basis for early detection of disease. Here, we present the origin of the α-sheet hypothesis and describe α-sheet structure and the corresponding mechanisms of conversion. We discuss experimental studies demonstrating that both mammalian and bacterial amyloid systems form α-sheet oligomers before converting to conventional β-sheet fibrils. Furthermore, we show that the process can be inhibited with de novo designed α-sheet peptides complementary to the structure in the toxic oligomers.
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Affiliation(s)
- Tatum Prosswimmer
- Molecular Engineering Program, University of Washington, Seattle, WA 98195-5013, USA
| | - Valerie Daggett
- Molecular Engineering Program, University of Washington, Seattle, WA 98195-5013, USA,Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
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15
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Hilt S, Liu R, Maezawa I, Rojalin T, Aung HH, Budamagunta M, Slez R, Gong Q, Carney RP, Voss JC. Novel Stilbene-Nitroxyl Hybrid Compounds Display Discrete Modulation of Amyloid Beta Toxicity and Structure. Front Chem 2022; 10:896386. [PMID: 35720993 PMCID: PMC9204515 DOI: 10.3389/fchem.2022.896386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Several neurodegenerative diseases are driven by misfolded proteins that assemble into soluble aggregates. These "toxic oligomers" have been associated with a plethora of cellular dysfunction and dysregulation, however the structural features underlying their toxicity are poorly understood. A major impediment to answering this question relates to the heterogeneous nature of the oligomers, both in terms of structural disorder and oligomer size. This not only complicates elucidating the molecular etiology of these disorders, but also the druggability of these targets as well. We have synthesized a class of bifunctional stilbenes to modulate both the conformational toxicity within amyloid beta oligomers (AβO) and the oxidative stress elicited by AβO. Using a neuronal culture model, we demonstrate this bifunctional approach has the potential to counter the molecular pathogenesis of Alzheimer's disease in a powerful, synergistic manner. Examination of AβO structure by various biophysical tools shows that each stilbene candidate uniquely alters AβO conformation and toxicity, providing insight towards the future development of structural correctors for AβO. Correlations of AβO structural modulation and bioactivity displayed by each provides insights for future testing in vivo. The multi-target activity of these hybrid molecules represents a highly advantageous feature for disease modification in Alzheimer's, which displays a complex, multifactorial etiology. Importantly, these novel small molecules intervene with intraneuronal AβO, a necessary feature to counter the cycle of dysregulation, oxidative stress and inflammation triggered during the earliest stages of disease progression.
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Affiliation(s)
- Silvia Hilt
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Ruiwu Liu
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Izumi Maezawa
- M.I.N.D. Institute and Department of Pathology and Laboratory Medicine, University of California, Davis, Davis, CA, United States
| | - Tatu Rojalin
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
| | - Hnin H. Aung
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
- Research Division, California Air Resource Board, Sacramento, CA, United States
| | - Madhu Budamagunta
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Ryan Slez
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Qizhi Gong
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Randy P. Carney
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
| | - John C. Voss
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
- Paramag Biosciences Inc., Davis, CA, United States
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16
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Abstract
Alzheimer’s Disease (AD) is a neurodegenerative disorder that is characterized clinically by progressive cognitive decline and pathologically by the β-sheet rich fibril plaque deposition of the amyloid-β (Aβ) peptide in the brain. While plaques are a hallmark of AD, plaque burden is not correlated with cognitive impairment. Instead, Aβ oligomers formed during the aggregation process represent the main agents of neurotoxicity, which occurs 10–20 years before patients begin to show symptoms. These oligomers are dynamic in nature and represented by a heterogeneous distribution of aggregates ranging from low- to high-molecular weight, some of which are toxic while others are not. A major difficulty in determining the pathological mechanism(s) of Aβ, developing reliable diagnostic markers for early-stage detection, as well as effective therapeutics for AD are the differentiation and characterization of oligomers formed throughout disease propagation based on their molecular features, effects on biological function, and relevance to disease propagation and pathology. Thus, it is critical to methodically identify the mechanisms of Aβ aggregation and toxicity, as well as describe the roles of different oligomers and aggregates in disease progression and molecular pathology. Here, we describe a variety of biophysical techniques used to isolate and characterize a range of Aβ oligomer populations, as well as discuss proposed mechanisms of toxicity and therapeutic interventions aimed at specific assemblies formed during the aggregation process. The approaches being used to map the misfolding and aggregation of Aβ are like what was done during the fundamental early studies, mapping protein folding pathways using combinations of biophysical techniques in concert with protein engineering. Such information is critical to the design and molecular engineering of future diagnostics and therapeutics for AD.
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17
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Mukherjee N, Lin L, Contreras CJ, Templin AT. β-Cell Death in Diabetes: Past Discoveries, Present Understanding, and Potential Future Advances. Metabolites 2021; 11:metabo11110796. [PMID: 34822454 PMCID: PMC8620854 DOI: 10.3390/metabo11110796] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 12/19/2022] Open
Abstract
β-cell death is regarded as a major event driving loss of insulin secretion and hyperglycemia in both type 1 and type 2 diabetes mellitus. In this review, we explore past, present, and potential future advances in our understanding of the mechanisms that promote β-cell death in diabetes, with a focus on the primary literature. We first review discoveries of insulin insufficiency, β-cell loss, and β-cell death in human diabetes. We discuss findings in humans and mouse models of diabetes related to autoimmune-associated β-cell loss and the roles of autoreactive T cells, B cells, and the β cell itself in this process. We review discoveries of the molecular mechanisms that underlie β-cell death-inducing stimuli, including proinflammatory cytokines, islet amyloid formation, ER stress, oxidative stress, glucotoxicity, and lipotoxicity. Finally, we explore recent perspectives on β-cell death in diabetes, including: (1) the role of the β cell in its own demise, (2) methods and terminology for identifying diverse mechanisms of β-cell death, and (3) whether non-canonical forms of β-cell death, such as regulated necrosis, contribute to islet inflammation and β-cell loss in diabetes. We believe new perspectives on the mechanisms of β-cell death in diabetes will provide a better understanding of this pathological process and may lead to new therapeutic strategies to protect β cells in the setting of diabetes.
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Affiliation(s)
- Noyonika Mukherjee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
| | - Li Lin
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
| | - Christopher J. Contreras
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
- Department of Medicine, Roudebush Veterans Affairs Medical Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Andrew T. Templin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
- Department of Medicine, Roudebush Veterans Affairs Medical Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Center for Diabetes and Metabolic Diseases, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
- Correspondence:
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18
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Effect of a Short Peptide with Alternating L- and D-Amino Acid on the Aggregation and Membrane Damage of hIAPP. Chem Res Chin Univ 2021. [DOI: 10.1007/s40242-021-0386-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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19
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Transthyretin Misfolding, A Fatal Structural Pathogenesis Mechanism. Int J Mol Sci 2021; 22:ijms22094429. [PMID: 33922648 PMCID: PMC8122960 DOI: 10.3390/ijms22094429] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/18/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Transthyretin (TTR) is an essential transporter of a thyroid hormone and a holo-retinol binding protein, found abundantly in human plasma and cerebrospinal fluid. In addition, this protein is infamous for its amyloidogenic propensity, causing various amyloidoses in humans, such as senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy. It has been known for over two decades that decreased stability of the native tetrameric conformation of TTR is the main cause of these diseases. Yet, mechanistic details on the amyloidogenic transformation of TTR were not clear until recent multidisciplinary investigations on various structural states of TTR. In this review, we discuss recent advancements in the structural understanding of TTR misfolding and amyloidosis processes. Special emphasis has been laid on the observations of novel structural features in various amyloidogenic species of TTR. In addition, proteolysis-induced fragmentation of TTR, a recently proposed mechanism facilitating TTR amyloidosis, has been discussed in light of its structural consequences and relevance to acknowledge the amyloidogenicity of TTR.
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20
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Hayward S, Milner-White EJ. Determination of amino acids that favour the α L region using Ramachandran propensity plots. Implications for α-sheet as the possible amyloid intermediate. J Struct Biol 2021; 213:107738. [PMID: 33838226 DOI: 10.1016/j.jsb.2021.107738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/01/2021] [Accepted: 04/04/2021] [Indexed: 11/28/2022]
Abstract
In amyloid diseases an insoluble amyloid fibril forms via a soluble oligomeric intermediate. It is this intermediate that mediates toxicity and it has been suggested, somewhat controversially, that it has the α-sheet structure. Nests and α-strands are similar peptide motifs in that alternate residues lie in the αR and γL regions of the Ramachandran plot for nests, or αR and αL regions for α-strands. In nests a concavity is formed by the main chain NH atoms whereas in α-strands the main chain is almost straight. Using "Ramachandran propensity plots" to focus on the αL/γL region, it is shown that glycine favours γL (82% of amino acids are glycine), but disfavours αL (3% are glycine). Most charged and polar amino acids favour αL with asparagine having by far the highest propensity. Thus, glycine favours nests but, contrary to common expectation, should not favour α-sheet. By contrast most charged or polar amino acids should favour α-sheet by their propensity for the αL conformation, which is more discriminating amongst amino acids than the αR conformation. Thus, these results suggest the composition of sequences that favour α-sheet formation and point towards effective prediction of α-sheet from sequence.
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Affiliation(s)
- Steven Hayward
- Computational Biology Laboratory, School of Computing Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - E James Milner-White
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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21
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Shen J. D-Amino acid substituted peptides as potential alternatives of homochiral L-configurations. Amino Acids 2021; 53:265-280. [PMID: 33537892 DOI: 10.1007/s00726-021-02947-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 01/22/2021] [Indexed: 11/28/2022]
Abstract
On the primitive Earth, both L- and D-amino acids would have been present. However, only L-amino acids are essential blocks to construct proteins in modern life. To study the relative stability of D-amino acid substituted peptides, a variety of computational methods were applied. Ten prebiotic amino acids (Gly, Ala, Asp, Glu, Ile, Leu, Pro, Ser, Thr, and Val) were previously determined by multiple meteorite, spark discharge, and hydrothermal vent studies. Some previously reported early Earth polypeptide analogs were focused on in this study. Tripeptides composed of only Asp, Ser, and Val exemplified that different positions (i.e., N-terminus, C-terminus, and middle) made a difference in the minimal folding energy of peptides, while the chemical classification of amino acid (hydrophobic, acidic, or hydroxylic) did not show a significant difference. Hierarchical cluster analysis for dipeptides with all possible combinations of the proposed ten prebiotic amino acids and their D-amino acid substituted derivatives generated five clusters. Primordial simple polypeptides were modeled to test the significance of molecular fluctuations, secondary structure occupancies, and folding energy differences based on these clusters. We found peptides with α-helices, long β-sheets, and long loops are usually less sensitive to D-amino acid replacements in comparison to short β-sheets. Intriguingly, amongst 129 D-amino acid residues, mutation sensitivity profiles presented that the ratio of more to less stable residues was about 1. In conclusion, some combinations of a mixture of L- and D-amino acids can potentially act as essential building blocks of life.
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Affiliation(s)
- Jianxun Shen
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, KY16 9AL, UK.
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22
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Meng F, Lu T, Wang Y, Zhao Y, Li Z, Li F. Role of Chain Extension in the Ability of Peptide Oligomers to Damage the Lipid Membrane Studied by the l- to d-Amino Acid Substitutions of hIAPP 18-27. J Phys Chem B 2020; 124:10147-10156. [PMID: 33140962 DOI: 10.1021/acs.jpcb.0c07656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exploration of the relation between the structural feature of oligomers and the ability of oligomers to damage the membrane has been an important subject in the study of the cytotoxic mechanism of amyloid proteins. In this work, we selected the hIAPP18-27 fragment as a model peptide and modified it by an alternating substitution of a d-amino acid for an l-amino acid in the hydrophilic N-terminal region, the hydrophobic C-terminal region, and the entire sequence. We prepared the oligomers using these peptides and investigated the effects of chain extension in different regions of the peptide on the ability of the oligomers to damage the membrane composed of POPC/POPG 4:1. We examined the morphology, structure, surface hydrophobicity, and packing compactness of the oligomers and monitored the changes in the structure and aggregation of the peptides upon interaction with the membrane. We found that the surface hydrophobicity and the disruptive ability of the oligomers are increased by an alternating l- and d-amino acid arrangement in the hydrophobic region of the peptide, while the packing compactness of the oligomers is increased and the disruptive ability of the oligomers decreased by an alternating l- and d-amino acid arrangement only in the hydrophilic region. The extension of the hydrophobic chain plays a significant role in the disruptive ability of the oligomers. Our results suggest that a positive relation between the surface hydrophobicity and the disruptive ability could be established only for the oligomers in which the peptide chains are flexible and loosely packed.
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Affiliation(s)
- Feihong Meng
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P. R. China
| | - Tong Lu
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P. R. China
| | - Yajie Wang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P. R. China
| | - Yanping Zhao
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P. R. China
| | - Zhengqiang Li
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P. R. China
| | - Fei Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, P. R. China
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23
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Das M, Bhargava BL. Exploring the candidates for a new protein folding - cross-α amyloid - in available protein databases. Phys Chem Chem Phys 2020; 22:23725-23734. [PMID: 33057523 DOI: 10.1039/d0cp03256e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Amyloid fibrils are formed from the assembly of soluble proteins and are responsible for many diseases. They are known to have a cross-β structure, where the fibril runs perpendicular to the β-sheets. A new type of tertiary structure formed by the aggregation of peptides in their α-helical form, in naturally occurring as well as synthetic peptides, termed cross-α amyloid has been reported recently. We have studied the interactions responsible for the formation of these cross-α amyloids and proposed a model to determine the peptides that could form these structures. Eight such peptides obtained using the model have been shown to form a cross-α structure using molecular dynamics simulations. The formation of a cross-α structure from eight copies of a randomly chosen peptide and its stability over a microsecond simulation have been demonstrated. A software named Cross-Alpha-Det has been developed that can determine whether a protein can form a cross-α structure from its secondary structure.
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Affiliation(s)
- Mitradip Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, 400005, India. and School of Chemical Sciences, National Institute of Science Education and Research - Bhubaneswar, HBNI, Jatni, Odisha 752050, India.
| | - B L Bhargava
- School of Chemical Sciences, National Institute of Science Education and Research - Bhubaneswar, HBNI, Jatni, Odisha 752050, India.
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24
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Pignataro MF, Herrera MG, Dodero VI. Evaluation of Peptide/Protein Self-Assembly and Aggregation by Spectroscopic Methods. Molecules 2020; 25:E4854. [PMID: 33096797 PMCID: PMC7587993 DOI: 10.3390/molecules25204854] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/17/2020] [Accepted: 10/19/2020] [Indexed: 01/08/2023] Open
Abstract
The self-assembly of proteins is an essential process for a variety of cellular functions including cell respiration, mobility and division. On the other hand, protein or peptide misfolding and aggregation is related to the development of Parkinson's disease and Alzheimer's disease, among other aggregopathies. As a consequence, significant research efforts are directed towards the understanding of this process. In this review, we are focused on the use of UV-Visible Absorption Spectroscopy, Fluorescence Spectroscopy and Circular Dichroism to evaluate the self-organization of proteins and peptides in solution. These spectroscopic techniques are commonly available in most chemistry and biochemistry research laboratories, and together they are a powerful approach for initial as well as routine evaluation of protein and peptide self-assembly and aggregation under different environmental stimulus. Furthermore, these spectroscopic techniques are even suitable for studying complex systems like those in the food industry or pharmaceutical formulations, providing an overall idea of the folding, self-assembly, and aggregation processes, which is challenging to obtain with high-resolution methods. Here, we compiled and discussed selected examples, together with our results and those that helped us better to understand the process of protein and peptide aggregation. We put particular emphasis on the basic description of the methods as well as on the experimental considerations needed to obtain meaningful information, to help those who are just getting into this exciting area of research. Moreover, this review is particularly useful to those out of the field who would like to improve reproducibility in their cellular and biomedical experiments, especially while working with peptide and protein systems as an external stimulus. Our final aim is to show the power of these low-resolution techniques to improve our understanding of the self-assembly of peptides and proteins and translate this fundamental knowledge in biomedical research or food applications.
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Affiliation(s)
- María Florencia Pignataro
- Department of Physiology and Molecular and Cellular Biology, Institute of Biosciences, Biotechnology and Translational Biology (iB3), Faculty of Exact and Natural Sciences, University of Buenos Aires, Buenos Aires C1428EG, Argentina;
- Institute of Biological Chemistry and Physical Chemistry, Dr. Alejandro Paladini, University of Buenos Aires-CONICET, Buenos Aires C1113AAD, Argentina
| | - María Georgina Herrera
- Department of Physiology and Molecular and Cellular Biology, Institute of Biosciences, Biotechnology and Translational Biology (iB3), Faculty of Exact and Natural Sciences, University of Buenos Aires, Buenos Aires C1428EG, Argentina;
- Institute of Biological Chemistry and Physical Chemistry, Dr. Alejandro Paladini, University of Buenos Aires-CONICET, Buenos Aires C1113AAD, Argentina
- Organic and Bioorganic Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Verónica Isabel Dodero
- Organic and Bioorganic Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
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25
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Mitra A, Sarkar N. Sequence and structure-based peptides as potent amyloid inhibitors: A review. Arch Biochem Biophys 2020; 695:108614. [PMID: 33010227 DOI: 10.1016/j.abb.2020.108614] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 02/07/2023]
Abstract
Misfolded and natively disordered globular proteins tend to aggregate together in an interwoven fashion to form fibrous, proteinaceous deposits referred to as amyloid fibrils. Formation and deposition of such insoluble fibrils are the characteristic features of a broad group of diseases, known as amyloidosis. Some of these proteins are known to cause several degenerative disorders in humans, such as Amyloid-Beta (Aβ) in Alzheimer's disease (AD), human Islet Amyloid Polypeptide (hIAPP, amylin) in type 2 diabetes, α-synuclein (α-syn) in Parkinson's disease (PD) and so on. The fact that these proteins do not share any significant sequence or structural homology in their native states make therapy quite challenging. However, it is observed that aggregation-prone proteins and peptides tend to adopt a similar type of secondary structure during the formation of fibrils. Rationally designed peptides can be a potent inhibitor that has been shown to disrupt the fibril structure by binding specifically to the amyloidogenic region(s) within a protein. The following review will analyze the inhibitory potency of both sequence-based and structure-based small peptides that have been shown to inhibit amyloidogenesis of proteins such as Aβ, human amylin, and α-synuclein.
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Affiliation(s)
- Amit Mitra
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, 769008, Odisha, India
| | - Nandini Sarkar
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, 769008, Odisha, India.
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Bromley D, Daggett V. Tumorigenic p53 mutants undergo common structural disruptions including conversion to α-sheet structure. Protein Sci 2020; 29:1983-1999. [PMID: 32715544 DOI: 10.1002/pro.3921] [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: 09/03/2019] [Revised: 05/15/2020] [Accepted: 07/17/2020] [Indexed: 12/28/2022]
Abstract
The p53 protein is a commonly studied cancer target because of its role in tumor suppression. Unfortunately, it is susceptible to mutation-associated loss of function; approximately 50% of cancers are associated with mutations to p53, the majority of which are located in the central DNA-binding domain. Here, we report molecular dynamics simulations of wild-type (WT) p53 and 20 different mutants, including a stabilized pseudo-WT mutant. Our findings indicate that p53 mutants tend to exacerbate latent structural-disruption tendencies, or vulnerabilities, already present in the WT protein, suggesting that it may be possible to develop cancer therapies by targeting a relatively small set of structural-disruption motifs rather than a multitude of effects specific to each mutant. In addition, α-sheet secondary structure formed in almost all of the proteins. α-Sheet has been hypothesized and recently demonstrated to play a role in amyloidogenesis, and its presence in the reported p53 simulations coincides with the recent re-consideration of cancer as an amyloid disease.
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Affiliation(s)
- Dennis Bromley
- Division of Biomedical and Health Informatics, Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, Washington, USA
| | - Valerie Daggett
- Division of Biomedical and Health Informatics, Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, Washington, USA.,Department of Bioengineering, University of Washington, Seattle, Washington, USA
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Templin AT, Mellati M, Soininen R, Hogan MF, Esser N, Castillo JJ, Zraika S, Kahn SE, Hull RL. Loss of perlecan heparan sulfate glycosaminoglycans lowers body weight and decreases islet amyloid deposition in human islet amyloid polypeptide transgenic mice. Protein Eng Des Sel 2020; 32:95-102. [PMID: 31769491 DOI: 10.1093/protein/gzz041] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/24/2019] [Accepted: 10/01/2019] [Indexed: 11/14/2022] Open
Abstract
Islet amyloid is a pathologic feature of type 2 diabetes (T2D) that is associated with β-cell loss and dysfunction. These amyloid deposits form via aggregation of the β-cell secretory product islet amyloid polypeptide (IAPP) and contain other molecules including the heparan sulfate proteoglycan perlecan. Perlecan has been shown to bind amyloidogenic human IAPP (hIAPP) via its heparan sulfate glycosaminoglycan (HS GAG) chains and to enhance hIAPP aggregation in vitro. We postulated that reducing the HS GAG content of perlecan would also decrease islet amyloid deposition in vivo. hIAPP transgenic mice were crossed with Hspg2Δ3/Δ3 mice harboring a perlecan mutation that prevents HS GAG attachment (hIAPP;Hspg2Δ3/Δ3), and male offspring from this cross were fed a high fat diet for 12 months to induce islet amyloid deposition. At the end of the study body weight, islet amyloid area, β-cell area, glucose tolerance and insulin secretion were analyzed. hIAPP;Hspg2Δ3/Δ3 mice exhibited significantly less islet amyloid deposition and greater β-cell area compared to hIAPP mice expressing wild type perlecan. hIAPP;Hspg2Δ3/Δ3 mice also gained significantly less weight than other genotypes. When adjusted for differences in body weight using multiple linear regression modeling, we found no differences in islet amyloid deposition or β-cell area between hIAPP transgenic and hIAPP;Hspg2Δ3/Δ3 mice. We conclude that loss of perlecan exon 3 reduces islet amyloid deposition in vivo through indirect effects on body weight and possibly also through direct effects on hIAPP aggregation. Both of these mechanisms may promote maintenance of glucose homeostasis in the setting of T2D.
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Affiliation(s)
- Andrew T Templin
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - Mahnaz Mellati
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - Raija Soininen
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Pentti Kaiteran Katu 1, Linnanmaa, Oulu, Finland
| | - Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - Nathalie Esser
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - J Josh Castillo
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
| | - Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, Veterans Affairs Puget Sound Health Care System and University of Washington, 1660 South Columbian Way, Seattle, 98108, Washington, USA
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Armiento V, Spanopoulou A, Kapurniotu A. Peptide-Based Molecular Strategies To Interfere with Protein Misfolding, Aggregation, and Cell Degeneration. Angew Chem Int Ed Engl 2020; 59:3372-3384. [PMID: 31529602 PMCID: PMC7064928 DOI: 10.1002/anie.201906908] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Indexed: 12/31/2022]
Abstract
Protein misfolding into amyloid fibrils is linked to more than 40 as yet incurable cell- and neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and type 2 diabetes. So far, however, only one of the numerous anti-amyloid molecules has reached patients. This Minireview gives an overview of molecular strategies and peptide chemistry "tools" to design, develop, and discover peptide-based molecules as anti-amyloid drug candidates. We focus on two major inhibitor rational design strategies: 1) the oldest and most common strategy, based on molecular recognition elements of amyloid self-assembly, and 2) a more recent approach, based on cross-amyloid interactions. We discuss why peptide-based amyloid inhibitors, in particular their advanced generations, can be promising leads or candidates for anti-amyloid drugs as well as valuable tools for deciphering amyloid-mediated cell damage and its link to disease pathogenesis.
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Affiliation(s)
- Valentina Armiento
- Division of Peptide BiochemistryTUM School of Life SciencesTechnische Universität MünchenEmil-Erlenmeyer-Forum 585354FreisingGermany
| | - Anna Spanopoulou
- Division of Peptide BiochemistryTUM School of Life SciencesTechnische Universität MünchenEmil-Erlenmeyer-Forum 585354FreisingGermany
- Current address: Coriolis Pharma Research GmbHFraunhoferstrasse 18B82152PlaneggGermany
| | - Aphrodite Kapurniotu
- Division of Peptide BiochemistryTUM School of Life SciencesTechnische Universität MünchenEmil-Erlenmeyer-Forum 585354FreisingGermany
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Aggregation Mechanism of Alzheimer's Amyloid β-Peptide Mediated by α-Strand/α-Sheet Structure. Int J Mol Sci 2020; 21:ijms21031094. [PMID: 32046006 PMCID: PMC7038184 DOI: 10.3390/ijms21031094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases and a widespread form of dementia. Aggregated forms of the amyloid β-peptide (Aβ) are identified as a toxic species responsible for neuronal damage in AD. Extensive research has been conducted to reveal the aggregation mechanism of Aβ. However, the structure of pathological aggregates and the mechanism of aggregation are not well understood. Recently, experimental studies have confirmed that the α-sheet structure in Aβ drives aggregation and toxicity in AD. However, how the α-sheet structure is formed in Aβ and how it contributes to Aβ aggregation remains elusive. In the present study, molecular dynamics simulations suggest that Aβ adopts the α-strand conformation by peptide-plane flipping. Multiple α-strands interact through hydrogen bonding to form α-sheets. This structure acts as a nucleus that initiates and promotes aggregation and fibrillation of Aβ. Our findings are supported by previous experimental as well as theoretical studies. This study provides valuable structural insights for the design of anti-AD drugs exploiting the α-strand/α-sheet structure.
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30
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Armiento V, Spanopoulou A, Kapurniotu A. Peptid‐basierte molekulare Strategien zum Einsatz bei Proteinfehlfaltung, Proteinaggregation und Zelldegeneration. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Valentina Armiento
- Fachgebiet PeptidbiochemieTUM School of Life SciencesTechnische Universität München Emil-Erlenmeyer-Forum 5 85354 Freising Deutschland
| | - Anna Spanopoulou
- Fachgebiet PeptidbiochemieTUM School of Life SciencesTechnische Universität München Emil-Erlenmeyer-Forum 5 85354 Freising Deutschland
- Aktuelle Adresse: Coriolis Pharma Research GmbH Fraunhoferstraße 18B 82152 Planegg Deutschland
| | - Aphrodite Kapurniotu
- Fachgebiet PeptidbiochemieTUM School of Life SciencesTechnische Universität München Emil-Erlenmeyer-Forum 5 85354 Freising Deutschland
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31
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Childers MC, Daggett V. Drivers of α-Sheet Formation in Transthyretin under Amyloidogenic Conditions. Biochemistry 2019; 58:4408-4423. [PMID: 31609590 DOI: 10.1021/acs.biochem.9b00769] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Amyloid diseases make up a set of fatal disorders in which proteins aggregate to form fibrils that deposit in tissues throughout the body. Amyloid-associated diseases are challenging to study because amyloid formation occurs on time scales that span several orders of magnitude and involve heterogeneous, interconverting protein conformations. The development of more effective technologies to diagnose and treat amyloid disease requires both a map of the conformations sampled during amyloidogenesis and an understanding of the molecular mechanisms that drive this process. In prior molecular dynamics simulations of amyloid proteins, we observed the formation of a nonstandard type of secondary structure, called α-sheet, that we proposed is associated with the pathogenic conformers in amyloid disease, the soluble oligomers. However, the detailed molecular interactions that drive the conversion to α-sheet remain elusive. Here we use molecular dynamics simulations to interrogate a critical event in transthyretin aggregation, the formation of aggregation-competent, monomeric species. We show that conformational changes in one of the two β-sheets in transthyretin enable solvent molecules and polar side chains to form electrostatic interactions with main-chain peptide groups to facilitate and modulate conversion to α-sheet secondary structure. Our results shed light on the early conformational changes that drive transthyretin toward the α-sheet structure associated with toxicity. Delineation of the molecular events that lead to aggregation at atomic resolution can aid strategies to target the early, critical toxic soluble oligomers.
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Affiliation(s)
- Matthew Carter Childers
- Department of Bioengineering , University of Washington , Seattle , Washington 98195-5013 , United States
| | - Valerie Daggett
- Department of Bioengineering , University of Washington , Seattle , Washington 98195-5013 , United States
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32
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Meng F, Lu T, Li F. Stabilization of Solvent to α-Sheet Structure and Conversion between α-Sheet and β-Sheet in the Fibrillation Process of Amyloid Peptide. J Phys Chem B 2019; 123:9576-9583. [DOI: 10.1021/acs.jpcb.9b07903] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Feihong Meng
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Qianjin Avenue 2699, Changchun 130012, P. R. China
| | - Tong Lu
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Qianjin Avenue 2699, Changchun 130012, P. R. China
| | - Fei Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Qianjin Avenue 2699, Changchun 130012, P. R. China
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33
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Laxio Arenas J, Kaffy J, Ongeri S. Peptides and peptidomimetics as inhibitors of protein–protein interactions involving β-sheet secondary structures. Curr Opin Chem Biol 2019; 52:157-167. [DOI: 10.1016/j.cbpa.2019.07.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 06/27/2019] [Accepted: 07/18/2019] [Indexed: 02/02/2023]
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α-Sheet secondary structure in amyloid β-peptide drives aggregation and toxicity in Alzheimer's disease. Proc Natl Acad Sci U S A 2019; 116:8895-8900. [PMID: 31004062 DOI: 10.1073/pnas.1820585116] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the deposition of β-sheet-rich, insoluble amyloid β-peptide (Aβ) plaques; however, plaque burden is not correlated with cognitive impairment in AD patients; instead, it is correlated with the presence of toxic soluble oligomers. Here, we show, by a variety of different techniques, that these Aβ oligomers adopt a nonstandard secondary structure, termed "α-sheet." These oligomers form in the lag phase of aggregation, when Aβ-associated cytotoxicity peaks, en route to forming nontoxic β-sheet fibrils. De novo-designed α-sheet peptides specifically and tightly bind the toxic oligomers over monomeric and fibrillar forms of Aβ, leading to inhibition of aggregation in vitro and neurotoxicity in neuroblastoma cells. Based on this specific binding, a soluble oligomer-binding assay (SOBA) was developed as an indirect probe of α-sheet content. Combined SOBA and toxicity experiments demonstrate a strong correlation between α-sheet content and toxicity. The designed α-sheet peptides are also active in vivo where they inhibit Aβ-induced paralysis in a transgenic Aβ Caenorhabditis elegans model and specifically target and clear soluble, toxic oligomers in a transgenic APPsw mouse model. The α-sheet hypothesis has profound implications for further understanding the mechanism behind AD pathogenesis.
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35
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Xi W, Hansmann UHE. The effect of retro-inverse D-amino acid Aβ-peptides on Aβ-fibril formation. J Chem Phys 2019; 150:095101. [PMID: 30849871 DOI: 10.1063/1.5082194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Peptides build from D-amino acids resist enzymatic degradation. The resulting extended time of biological activity makes them prime candidates for the development of pharmaceuticals. Of special interest are D-retro-inverso (DRI) peptides where a reversed sequence of D-amino acids leads to molecules with almost the same structure, stability, and bioactivity as the parent L-peptides but increased resistance to proteolytic degradation. Here, we study the effect of DRI-Aβ40 and DRI-Aβ42 peptides on fibril formation. Using molecular dynamics simulations, we compare the stability of typical amyloid fibril models with such where the L-peptides are replaced by DRI-Aβ40 and DRI-Aβ42 peptides. We then explore the likelihood for cross fibrilization of Aβ L- and DRI-peptides by investigating how the presence of DRI peptides alters the elongation and stability of L-Aβ-fibrils. Our data suggest that full-length DRI-peptides may enhance the fibril formation and decrease the ratio of soluble toxic Aβ oligomers, pointing out potential for D-amino-acid-based drug design targeting Alzheimer's disease.
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Affiliation(s)
- Wenhui Xi
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Ulrich H E Hansmann
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
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36
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Computational insights into the role of α-strand/sheet in aggregation of α-synuclein. Sci Rep 2019; 9:59. [PMID: 30635607 PMCID: PMC6329781 DOI: 10.1038/s41598-018-37276-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/05/2018] [Indexed: 01/03/2023] Open
Abstract
The α-synuclein is a major component of amyloid fibrils found in Lewy bodies, the characteristic intracellular proteinaceous deposits which are pathological hallmarks of neurodegenerative diseases such as Parkinson’s disease (PD) and dementia. It is an intrinsically disordered protein that may undergo dramatic structural changes to form amyloid fibrils. Aggregation process from α-synuclein monomers to amyloid fibrils through oligomeric intermediates is considered as the disease-causative toxic mechanism. However, mechanism underlying aggregation is not well-known despite several attempts. To characterize the mechanism, we have explored the effects of pH and temperature on the structural properties of wild-type and mutant α-synuclein using molecular dynamics (MD) simulation technique. MD studies suggested that amyloid fibrils can grow by monomer. Conformational transformation of the natively unfolded protein into partially folded intermediate could be accountable for aggregation and fibrillation. An intermediate α-strand was observed in the hydrophobic non-amyloid-β component (NAC) region of α-synuclein that could proceed to α-sheet and initiate early assembly events. Water network around the intermediate was analyzed to determine its influence on the α-strand structure. Findings of this study provide novel insights into possible mechanism of α-synuclein aggregation and promising neuroprotective strategy that could aid alleviate PD and its symptoms.
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37
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Kazmi S, Mujeeb AA, Owais M. Cyclic undecapeptide Cyclosporin A mediated inhibition of amyloid synthesis: Implications in alleviation of amyloid induced neurotoxicity. Sci Rep 2018; 8:17283. [PMID: 30470780 PMCID: PMC6251898 DOI: 10.1038/s41598-018-35645-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 10/12/2018] [Indexed: 11/24/2022] Open
Abstract
Amyloids are highly organized fibril aggregates arise from inappropriately folded form of the protein or polypeptide precursors under both physiological as well as simulated ambience. Amyloid synthesis is a multistep process that involves formation of several metastable intermediates. Among various intermediate species, the as-formed soluble oligomers are extremely toxic to the neuronal cells. In the present study, we evaluated cyclosporine A (CsA), an undecapeptide, for its potential to prevent aggregation of model protein ovalbumin (OVA). In an attempt to elucidate involved operative mechanism, the preliminary studies delineate that CsA affects both primary nucleation as well as other secondary pathways involved in OVA fibrillation process. By its specific interaction with amyloid intermediates, the cyclic peptide CsA seems to regulate the lag phase of the fibrillation process in concentration dependent manner. The present study further suggests that exposure to CsA during lag phase ensues in reversal of OVA fibrillation process. On the contrary, mature OVA fibril remained impervious to the CsA treatment. The cyclic undecapeptide CsA was also found to successfully alleviate amyloid induced toxicity in neuroblastoma cells.
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Affiliation(s)
- Shadab Kazmi
- Molecular Immunology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002, India
| | - Anzar Abdul Mujeeb
- Molecular Immunology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002, India
| | - Mohammad Owais
- Molecular Immunology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002, India.
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Paranjapye N, Daggett V. De Novo Designed α-Sheet Peptides Inhibit Functional Amyloid Formation of Streptococcus mutans Biofilms. J Mol Biol 2018; 430:3764-3773. [PMID: 30006266 PMCID: PMC6168415 DOI: 10.1016/j.jmb.2018.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 06/29/2018] [Accepted: 07/02/2018] [Indexed: 12/11/2022]
Abstract
Streptococcus mutans is a bacterial species that predominates in the oral microbiome. S. mutans binds to the tooth surface, metabolizes sugars and produces acid, leading to cavity formation. S. mutans can also cause infectious endocarditis. Recent evidence suggests that S. mutans biofilms contain amyloid fibrils. Amyloids are insoluble fibrillar protein aggregates, and bacteria use functional amyloids to improve robustness of their biofilms. While the functional amyloids in bacteria such as Escherichia coli and Staphylococcus aureus have been heavily investigated, little is known about the mechanism of S. mutans amyloid formation. Previous results from our laboratory with the amyloidogenic proteins and peptides from the aforementioned bacteria and other mammalian amyloid systems suggest that amyloid formation progresses via an intermediate that adopts a unique secondary structure-α-sheet. De novo designed peptides with alternating l- and d-amino acid also adopt an α-sheet secondary structure and inhibit amyloid formation by binding to soluble oligomeric species during amyloidogenesis. Inhibition of fibrillization by α-sheet peptides suggests the presence of α-sheet during amyloid formation. To investigate the mechanism of functional amyloid formation in S. mutans, α-sheet peptides were compared to epigallocatechin gallate for their ability to inhibit fibril formation in S. mutans. Inhibition was demonstrated in a biofilm plate assay and on hydroxyapatite surfaces both in S. mutans alone and in bacteria from human saliva. The observed inhibition suggests that an α-sheet mediated mechanism may be operative during functional amyloid formation.
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Affiliation(s)
- Natasha Paranjapye
- Department of Bioengineering, University of Washington, Box 355013, Seattle, WA 98195-5013, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Box 355013, Seattle, WA 98195-5013, USA.
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39
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Templin AT, Meier DT, Willard JR, Wolden-Hanson T, Conway K, Lin YG, Gillespie PJ, Bokvist KB, Attardo G, Kahn SE, Scheuner D, Hull RL. Use of the PET ligand florbetapir for in vivo imaging of pancreatic islet amyloid deposits in hIAPP transgenic mice. Diabetologia 2018; 61:2215-2224. [PMID: 30046852 PMCID: PMC6119478 DOI: 10.1007/s00125-018-4695-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/19/2018] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Islet amyloid deposits contribute to beta cell dysfunction and death in most individuals with type 2 diabetes but non-invasive methods to determine the presence of these pathological protein aggregates are currently not available. Therefore, we examined whether florbetapir, a radiopharmaceutical agent used for detection of amyloid-β deposits in the brain, also allows identification of islet amyloid in the pancreas. METHODS Saturation binding assays were used to determine the affinity of florbetapir for human islet amyloid polypeptide (hIAPP) aggregates in vitro. Islet amyloid-prone transgenic mice that express hIAPP in their beta cells and amyloid-free non-transgenic control mice were used to examine the ability of florbetapir to detect islet amyloid deposits in vitro, in vivo and ex vivo. Mice or mouse pancreases were subjected to autoradiographic, histochemical and/or positron emission tomography (PET) analyses to assess the utility of florbetapir in identifying islet amyloid. RESULTS In vitro, florbetapir bound synthetic hIAPP fibrils with a dissociation constant of 7.9 nmol/l. Additionally, florbetapir bound preferentially to amyloid-containing hIAPP transgenic vs amyloid-free non-transgenic mouse pancreas sections in vitro, as determined by autoradiography (16,475 ± 5581 vs 5762 ± 575 density/unit area, p < 0.05). In hIAPP transgenic and non-transgenic mice fed a high-fat diet for 1 year, intravenous administration of florbetapir followed by PET scanning showed that the florbetapir signal was significantly higher in amyloid-laden hIAPP transgenic vs amyloid-free non-transgenic pancreases in vivo during the first 5 min of the scan (36.83 ± 2.22 vs 29.34 ± 2.03 standardised uptake value × min, p < 0.05). Following PET, pancreases were excised and florbetapir uptake was determined ex vivo by γ counting. Pancreatic uptake of florbetapir was significantly correlated with the degree of islet amyloid deposition, the latter assessed by histochemistry (r = 0.74, p < 0.001). CONCLUSIONS/INTERPRETATION Florbetapir binds to islet amyloid deposits in a specific and quantitative manner. In the future, florbetapir may be useful as a non-invasive tool to identify islet amyloid deposits in humans.
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Affiliation(s)
- Andrew T Templin
- Department of Medicine, VA Puget Sound Health Care System, 1660 S. Columbian Way, Seattle, WA, 98108, USA.
- University of Washington, Seattle, WA, USA.
| | - Daniel T Meier
- Department of Medicine, VA Puget Sound Health Care System, 1660 S. Columbian Way, Seattle, WA, 98108, USA
- University of Washington, Seattle, WA, USA
| | - Joshua R Willard
- Department of Medicine, VA Puget Sound Health Care System, 1660 S. Columbian Way, Seattle, WA, 98108, USA
- University of Washington, Seattle, WA, USA
| | - Tami Wolden-Hanson
- Department of Medicine, VA Puget Sound Health Care System, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Kelly Conway
- Avid Radiopharmaceuticals, Inc., Philadelphia, PA, USA
| | - Yin-Guo Lin
- Avid Radiopharmaceuticals, Inc., Philadelphia, PA, USA
| | | | | | | | - Steven E Kahn
- Department of Medicine, VA Puget Sound Health Care System, 1660 S. Columbian Way, Seattle, WA, 98108, USA
- University of Washington, Seattle, WA, USA
| | | | - Rebecca L Hull
- Department of Medicine, VA Puget Sound Health Care System, 1660 S. Columbian Way, Seattle, WA, 98108, USA
- University of Washington, Seattle, WA, USA
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40
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Bi TM, Daggett V. The Role of α-sheet in Amyloid Oligomer Aggregation and Toxicity. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2018; 91:247-255. [PMID: 30258312 PMCID: PMC6153628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A major barrier to developing effective treatments and diagnostics for amyloid diseases is the inability of traditional protein structure characterization methods to elucidate the structure of the toxic oligomers that form during amyloidogenesis. Some years ago, our lab "discovered" a novel protein secondary structure in molecular dynamics simulations of multiple unrelated amyloid proteins, which we call α-sheet. We hypothesize that α-sheet plays an important role in amyloid aggregation and oligomer toxicity. De novo monomeric α-sheet peptides designed to be complementary to the structure observed in simulations inhibit amyloid aggregation and toxicity and specifically bind to the toxic oligomeric species in a variety of unrelated mammalian and bacterial amyloid systems associated with a range of diseases. Furthermore, spectroscopic analysis of α-sheet structure, including nuclear magnetic resonance (NMR), circular dichroism (CD), and Fourier-transform infrared spectroscopy (FTIR), correspond well to values predicted for α-sheet. These α-sheet designs are now being tested for their ability to detect and neutralize toxic oligomers in animals and in patient samples, demonstrating the potential of this nonstandard secondary structure as a target for therapeutic and diagnostic agents for amyloid diseases.
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Affiliation(s)
- Timothy M. Bi
- Department of Bioengineering, University of Washington, Seattle, WA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA
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41
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Ryan P, Patel B, Makwana V, Jadhav HR, Kiefel M, Davey A, Reekie TA, Rudrawar S, Kassiou M. Peptides, Peptidomimetics, and Carbohydrate-Peptide Conjugates as Amyloidogenic Aggregation Inhibitors for Alzheimer's Disease. ACS Chem Neurosci 2018; 9:1530-1551. [PMID: 29782794 DOI: 10.1021/acschemneuro.8b00185] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder accounting for 60-80% of dementia cases. For many years, AD causality was attributed to amyloid-β (Aβ) aggregated species. Recently, multiple therapies that target Aβ aggregation have failed in clinical trials, since Aβ aggregation is found in AD and healthy patients. Attention has therefore shifted toward the aggregation of the tau protein as a major driver of AD. Numerous inhibitors of tau-based pathology have recently been developed. Diagnosis of AD has shifted from measuring late stage senile plaques to early stage biomarkers, amyloid-β and tau monomers and oligomeric assemblies. Synthetic peptides and some derivative structures are being explored for use as theranostic tools as they possess the capacity both to bind the biomarkers and to inhibit their pathological self-assembly. Several studies have demonstrated that O-linked glycoside addition can significantly alter amyloid aggregation kinetics. Furthermore, natural O-glycosylation of amyloid-forming proteins, including amyloid precursor protein (APP), tau, and α-synuclein, promotes alternative nonamyloidogenic processing pathways. As such, glycopeptides and related peptidomimetics are being investigated within the AD field. Here we review advancements made in the last 5 years, as well as the arrival of sugar-based derivatives.
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Affiliation(s)
- Philip Ryan
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast 4222, Australia
| | - Bhautikkumar Patel
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast 4222, Australia
| | - Vivek Makwana
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast 4222, Australia
| | - Hemant R. Jadhav
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Pilani-333031, Rajasthan, India
| | - Milton Kiefel
- Institute for Glycomics, Griffith University, Gold Coast 4222, Australia
| | - Andrew Davey
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast 4222, Australia
- Menzies Health Institute Queensland, Griffith University, Gold Coast 4222, Australia
- Quality Use of Medicines Network, Griffith University, Gold Coast 4222, Australia
| | | | - Santosh Rudrawar
- School of Pharmacy and Pharmacology, Griffith University, Gold Coast 4222, Australia
- Menzies Health Institute Queensland, Griffith University, Gold Coast 4222, Australia
- Quality Use of Medicines Network, Griffith University, Gold Coast 4222, Australia
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, NSW 2006, Australia
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Childers MC, Towse CL, Daggett V. Molecular dynamics-derived rotamer libraries for d-amino acids within homochiral and heterochiral polypeptides. Protein Eng Des Sel 2018; 31:191-204. [PMID: 29992252 PMCID: PMC6205366 DOI: 10.1093/protein/gzy016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 06/15/2018] [Indexed: 01/06/2023] Open
Abstract
Computational resources have contributed to the design and engineering of novel proteins by integrating genomic, structural and dynamic aspects of proteins. Non-canonical amino acids, such as d-amino acids, expand the available sequence space for designing and engineering proteins; however, the rotamer libraries for d-amino acids are usually constructed as the mirror images of l-amino acid rotamer libraries, an assumption that has not been tested. To this end, we have performed molecular dynamics (MD) simulations of model host-guest peptide systems containing d-amino acids. Our simulations systematically address the applicability of the mirror image convention as well as the effects of neighboring residue chirality. Rotamer libraries derived from these systems provide realistic rotamer distributions suitable for use in both rational and computational design workflows. Our simulations also address the impact of chirality on the intrinsic conformational preferences of amino acids, providing fundamental insights into the relationship between chirality and biomolecular dynamics. While d-amino acids are rare in naturally occurring proteins, they are used in designed proteins to stabilize a desired conformation, increase bioavailability or confer favorable biochemical and physical attributes. Here, we present d-amino acid rotamer libraries derived from MD simulations of alanine-based host-guest pentapeptides and show how certain residues can deviate from mirror image symmetry. Our simulations directly model d-amino acids as guest residues within the chiral l-Ala and d-Ala pentapeptide series to explicitly incorporate any contributions resulting from the chiralities of neighboring residues.
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Affiliation(s)
| | - Clare-Louise Towse
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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Bhattacharya S, Xu L, Thompson D. Revisiting the earliest signatures of amyloidogenesis: Roadmaps emerging from computational modeling and experiment. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Shayon Bhattacharya
- Department of Physics, Bernal InstituteUniversity of LimerickLimerickIreland
| | - Liang Xu
- Department of Physics, Bernal InstituteUniversity of LimerickLimerickIreland
| | - Damien Thompson
- Department of Physics, Bernal InstituteUniversity of LimerickLimerickIreland
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Ribarič S. Peptides as Potential Therapeutics for Alzheimer's Disease. Molecules 2018; 23:E283. [PMID: 29385735 PMCID: PMC6017258 DOI: 10.3390/molecules23020283] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 01/26/2018] [Accepted: 01/28/2018] [Indexed: 12/22/2022] Open
Abstract
Intracellular synthesis, folding, trafficking and degradation of proteins are controlled and integrated by proteostasis. The frequency of protein misfolding disorders in the human population, e.g., in Alzheimer's disease (AD), is increasing due to the aging population. AD treatment options are limited to symptomatic interventions that at best slow-down disease progression. The key biochemical change in AD is the excessive accumulation of per-se non-toxic and soluble amyloid peptides (Aβ(1-37/44), in the intracellular and extracellular space, that alters proteostasis and triggers Aβ modification (e.g., by reactive oxygen species (ROS)) into toxic intermediate, misfolded soluble Aβ peptides, Aβ dimers and Aβ oligomers. The toxic intermediate Aβ products aggregate into progressively less toxic and less soluble protofibrils, fibrils and senile plaques. This review focuses on peptides that inhibit toxic Aβ oligomerization, Aβ aggregation into fibrils, or stabilize Aβ peptides in non-toxic oligomers, and discusses their potential for AD treatment.
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Affiliation(s)
- Samo Ribarič
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, SI-1000 Ljubljana, Slovenia.
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45
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Nusrat S, Zaman M, Masroor A, Siddqi MK, Zaidi N, Neelofar K, Abdelhameed AS, Khan RH. Deciphering the enhanced inhibitory, disaggregating and cytoprotective potential of promethazine towards amyloid fibrillation. Int J Biol Macromol 2018; 106:851-863. [DOI: 10.1016/j.ijbiomac.2017.08.081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/12/2017] [Accepted: 08/13/2017] [Indexed: 11/26/2022]
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46
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Maris NL, Shea D, Bleem A, Bryers JD, Daggett V. Chemical and Physical Variability in Structural Isomers of an l/d α-Sheet Peptide Designed To Inhibit Amyloidogenesis. Biochemistry 2017; 57:507-510. [PMID: 29202245 DOI: 10.1021/acs.biochem.7b00345] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
There has been much interest in synthetic peptides as inhibitors of aggregation associated with amyloid diseases. Of particular interest are compounds that target the cytotoxic soluble oligomers preceding the formation of mature, nontoxic fibrils. This study explores physical and chemical differences between two de novo-designed peptides that share an identical primary structure but differ in backbone chirality at six key positions. We show that the presence of alternating l/d-amino acid motifs dramatically increases aqueous solubility, enforces α-sheet secondary structure, and inhibits aggregation of the β-amyloid peptide implicated in Alzheimer's disease, in addition to neutralizing its cytotoxicity. In contrast, the all-l-amino acid isomer does not form α-sheet structure and is insoluble and inactive.
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Affiliation(s)
- Nathan L Maris
- Department of Bioengineering and ‡Department of Molecular Engineering, University of Washington , Box 355013, Seattle, Washington 98195-5013, United States
| | - Dylan Shea
- Department of Bioengineering and ‡Department of Molecular Engineering, University of Washington , Box 355013, Seattle, Washington 98195-5013, United States
| | - Alissa Bleem
- Department of Bioengineering and ‡Department of Molecular Engineering, University of Washington , Box 355013, Seattle, Washington 98195-5013, United States
| | - James D Bryers
- Department of Bioengineering and ‡Department of Molecular Engineering, University of Washington , Box 355013, Seattle, Washington 98195-5013, United States
| | - Valerie Daggett
- Department of Bioengineering and ‡Department of Molecular Engineering, University of Washington , Box 355013, Seattle, Washington 98195-5013, United States
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47
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Templin AT, Samarasekera T, Meier DT, Hogan MF, Mellati M, Crow MT, Kitsis RN, Zraika S, Hull RL, Kahn SE. Apoptosis Repressor With Caspase Recruitment Domain Ameliorates Amyloid-Induced β-Cell Apoptosis and JNK Pathway Activation. Diabetes 2017; 66:2636-2645. [PMID: 28729244 PMCID: PMC5606321 DOI: 10.2337/db16-1352] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 07/13/2017] [Indexed: 12/28/2022]
Abstract
Islet amyloid is present in more than 90% of individuals with type 2 diabetes, where it contributes to β-cell apoptosis and insufficient insulin secretion. Apoptosis repressor with caspase recruitment domain (ARC) binds and inactivates components of the intrinsic and extrinsic apoptosis pathways and was recently found to be expressed in islet β-cells. Using a human islet amyloid polypeptide transgenic mouse model of islet amyloidosis, we show ARC knockdown increases amyloid-induced β-cell apoptosis and loss, while ARC overexpression decreases amyloid-induced apoptosis, thus preserving β-cells. These effects occurred in the absence of changes in islet amyloid deposition, indicating ARC acts downstream of amyloid formation. Because islet amyloid increases c-Jun N-terminal kinase (JNK) pathway activation, we investigated whether ARC affects JNK signaling in amyloid-forming islets. We found ARC knockdown enhances JNK pathway activation, whereas ARC overexpression reduces JNK, c-Jun phosphorylation, and c-Jun target gene expression (Jun and Tnf). Immunoprecipitation of ARC from mouse islet lysates showed ARC binds JNK, suggesting interaction between JNK and ARC decreases amyloid-induced JNK phosphorylation and downstream signaling. These data indicate that ARC overexpression diminishes amyloid-induced JNK pathway activation and apoptosis in the β-cell, a strategy that may reduce β-cell loss in type 2 diabetes.
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Affiliation(s)
- Andrew T Templin
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Tanya Samarasekera
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Daniel T Meier
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Meghan F Hogan
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Mahnaz Mellati
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Michael T Crow
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Richard N Kitsis
- Departments of Medicine and Cell Biology and Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY
| | - Sakeneh Zraika
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Rebecca L Hull
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Steven E Kahn
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
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48
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Bleem A, Francisco R, Bryers JD, Daggett V. Designed α-sheet peptides suppress amyloid formation in Staphylococcus aureus biofilms. NPJ Biofilms Microbiomes 2017; 3:16. [PMID: 28685098 PMCID: PMC5495782 DOI: 10.1038/s41522-017-0025-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 06/06/2017] [Accepted: 06/13/2017] [Indexed: 12/13/2022] Open
Abstract
Nosocomial infections affect hundreds of millions of patients worldwide each year, and ~60% of these infections are associated with biofilm formation on an implanted medical device. Biofilms are dense communities of microorganisms in which cells associate with surfaces and each other using a self-produced extracellular matrix composed of proteins, polysaccharides, and genetic material. Proteins in the extracellular matrix take on a variety of forms, but here we focus on functional amyloid structures. Amyloids have long been associated with protein misfolding and neurodegenerative diseases, but recent research has demonstrated that numerous bacterial species utilize the amyloid fold to fortify the biofilm matrix and resist disassembly. Consequently, these functional amyloids, in particular the soluble oligomeric intermediates formed during amyloidogenesis, represent targets to destabilize the extracellular matrix and interrupt biofilm formation. Our previous studies suggested that these amyloidogenic intermediates adopt a non-standard structure, termed "α-sheet", as they aggregate into soluble oligomeric species. This led to the design of complementary α-sheet peptides as anti-α-sheet inhibitors; these designs inhibit amyloidogenesis in three unrelated mammalian disease-associated systems through preferential binding of soluble oligomers. Here we show that these anti-α-sheet peptides inhibit amyloid formation in Staphylococcus aureus biofilms. Furthermore, they inhibit aggregation of pure, synthetic phenol soluble modulin α1, a major component of Staphylococcus aureus functional amyloids. As it aggregates phenol soluble modulin α1 adopts α-helix then α-sheet and finally forms β-sheet fibrils. The binding of the designed peptide inhibitors coincides with the formation of α-sheet.
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Affiliation(s)
- Alissa Bleem
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
| | - Robyn Francisco
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
| | - James D. Bryers
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
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49
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Nusrat S, Zaidi N, Siddiqi MK, Zaman M, Siddique IA, Ajmal MR, Abdelhameed AS, Khan RH. Anti-Parkinsonian L-Dopa can also act as anti-systemic amyloidosis—A mechanistic exploration. Int J Biol Macromol 2017; 99:630-640. [DOI: 10.1016/j.ijbiomac.2017.03.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 01/15/2023]
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50
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Childers MC, Daggett V. Insights from molecular dynamics simulations for computational protein design. MOLECULAR SYSTEMS DESIGN & ENGINEERING 2017; 2:9-33. [PMID: 28239489 PMCID: PMC5321087 DOI: 10.1039/c6me00083e] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A grand challenge in the field of structural biology is to design and engineer proteins that exhibit targeted functions. Although much success on this front has been achieved, design success rates remain low, an ever-present reminder of our limited understanding of the relationship between amino acid sequences and the structures they adopt. In addition to experimental techniques and rational design strategies, computational methods have been employed to aid in the design and engineering of proteins. Molecular dynamics (MD) is one such method that simulates the motions of proteins according to classical dynamics. Here, we review how insights into protein dynamics derived from MD simulations have influenced the design of proteins. One of the greatest strengths of MD is its capacity to reveal information beyond what is available in the static structures deposited in the Protein Data Bank. In this regard simulations can be used to directly guide protein design by providing atomistic details of the dynamic molecular interactions contributing to protein stability and function. MD simulations can also be used as a virtual screening tool to rank, select, identify, and assess potential designs. MD is uniquely poised to inform protein design efforts where the application requires realistic models of protein dynamics and atomic level descriptions of the relationship between dynamics and function. Here, we review cases where MD simulations was used to modulate protein stability and protein function by providing information regarding the conformation(s), conformational transitions, interactions, and dynamics that govern stability and function. In addition, we discuss cases where conformations from protein folding/unfolding simulations have been exploited for protein design, yielding novel outcomes that could not be obtained from static structures.
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Affiliation(s)
| | - Valerie Daggett
- Corresponding author: , Phone: 1.206.685.7420, Fax: 1.206.685.3300
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