51
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Sheng J, Olrichs NK, Geerts WJ, Kaloyanova DV, Helms JB. Metal ions and redox balance regulate distinct amyloid-like aggregation pathways of GAPR-1. Sci Rep 2019; 9:15048. [PMID: 31636315 PMCID: PMC6803662 DOI: 10.1038/s41598-019-51232-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 09/26/2019] [Indexed: 01/10/2023] Open
Abstract
Members of the CAP superfamily (Cysteine-rich secretory proteins, Antigen 5, and Pathogenesis-Related 1 proteins) are characterized by the presence of a structurally conserved CAP domain. The common structure-function relationship of this domain is still poorly understood. In this study, we unravel specific molecular mechanisms modulating the quaternary structure of the mammalian CAP protein GAPR-1 (Golgi-Associated plant Pathogenesis-Related protein 1). Copper ions are shown to induce a distinct amyloid-like aggregation pathway of GAPR-1 in the presence of heparin. This involves an immediate shift from native multimers to monomers which are prone to form amyloid-like fibrils. The Cu2+-induced aggregation pathway is independent of a conserved metal-binding site and involves the formation of disulfide bonds during the nucleation process. The elongation process occurs independently of the presence of Cu2+ ions, and amyloid-like aggregation can proceed under oxidative conditions. In contrast, the Zn2+-dependent aggregation pathway was found to be independent of cysteines and was reversible upon removal of Zn2+ ions. Together, our results provide insight into the regulation of the quaternary structure of GAPR-1 by metal ions and redox homeostasis with potential implications for regulatory mechanisms of other CAP proteins.
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Affiliation(s)
- Jie Sheng
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Nick K Olrichs
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Willie J Geerts
- Biomolecular Imaging, Bijvoet Center, Utrecht University, Utrecht, The Netherlands
| | - Dora V Kaloyanova
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - J Bernd Helms
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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52
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Gosztyla ML, Brothers HM, Robinson SR. Alzheimer's Amyloid-β is an Antimicrobial Peptide: A Review of the Evidence. J Alzheimers Dis 2019; 62:1495-1506. [PMID: 29504537 DOI: 10.3233/jad-171133] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The amyloid-β (Aβ) peptide has long been considered to be the driving force behind Alzheimer's disease (AD). However, clinical trials that have successfully reduced Aβ burden in the brain have not slowed the cognitive decline, and in some instances, have resulted in adverse outcomes. While these results can be interpreted in different ways, a more nuanced picture of Aβ is emerging that takes into account the facts that the peptide is evolutionarily conserved and is present throughout life in cognitively normal individuals. Recent evidence indicates a role for Aβ as an antimicrobial peptide (AMP), a class of innate immune defense molecule that utilizes fibrillation to protect the host from a wide range of infectious agents. In humans and in animal models, infection of the brain frequently leads to increased amyloidogenic processing of the amyloid-β protein precursor (AβPP) and resultant fibrillary aggregates of Aβ. Evidence from in vitro and in vivo studies demonstrates that Aβ oligomers have potent, broad-spectrum antimicrobial properties by forming fibrils that entrap pathogens and disrupt cell membranes. Importantly, overexpression of Aβ confers increased resistance to infection from both bacteria and viruses. The antimicrobial role of Aβ may explain why increased rates of infection have been observed in some of the AD clinical trials that depleted Aβ. Perhaps progress toward a cure for AD will accelerate once treatment strategies begin to take into account the likely physiological functions of this enigmatic peptide.
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Affiliation(s)
- Maya L Gosztyla
- Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Holly M Brothers
- Department of Psychology, The Ohio State University, Columbus, OH, USA
| | - Stephen R Robinson
- Discipline of Psychology, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
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53
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Gour S, Kumar V, Singh A, Gadhave K, Goyal P, Pandey J, Giri R, Yadav JK. Mammalian antimicrobial peptide protegrin‐4 self assembles and forms amyloid‐like aggregates: Assessment of its functional relevance. J Pept Sci 2019; 25:e3151. [DOI: 10.1002/psc.3151] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 12/18/2018] [Accepted: 01/13/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Shalini Gour
- Department of BiotechnologyCentral University of Rajasthan Ajmer India
| | - Vijay Kumar
- Department of BiotechnologyCentral University of Rajasthan Ajmer India
| | - Ashutosh Singh
- School of Basic SciencesIndian Institute of Technology Mandi Kamand India
| | - Kundlik Gadhave
- School of Basic SciencesIndian Institute of Technology Mandi Kamand India
| | - Pankaj Goyal
- Department of BiotechnologyCentral University of Rajasthan Ajmer India
| | - Janmejay Pandey
- Department of BiotechnologyCentral University of Rajasthan Ajmer India
| | - Rajanish Giri
- School of Basic SciencesIndian Institute of Technology Mandi Kamand India
| | - Jay Kant Yadav
- Department of BiotechnologyCentral University of Rajasthan Ajmer India
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54
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Cámara-Almirón J, Caro-Astorga J, de Vicente A, Romero D. Beyond the expected: the structural and functional diversity of bacterial amyloids. Crit Rev Microbiol 2018; 44:653-666. [PMID: 30354913 DOI: 10.1080/1040841x.2018.1491527] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intense research has confirmed the formerly theoretical distribution of amyloids in nature, and studies on different systems have illustrated the role of these proteins in microbial adaptation and in interactions with the environment. Two lines of research are expanding our knowledge on functional amyloids: (i) structural studies providing insights into the molecular machineries responsible for the transition from monomer to fibers and (ii) studies showing the way in which these proteins might participate in the microbial fitness in natural settings. Much is known about how amyloids play a role in the social behavior of bacteria, or biofilm formation, and in the adhesion of bacteria to surfaces; however, we are still in the initial stages of understanding a complementary involvement of amyloids in bacteria-host interactions. This review will cover the following two topics: first, the key aspects of the microbial platforms dedicated to the assembly of the fibers, and second, the mechanisms by which bacteria utilize the morphological and biochemical variability of amyloids to modulate the immunological response of the host, plants and humans, contributing to (i) infection, in the case of pathogenic bacteria or (ii) promotion of the health of the host, in the case of beneficial bacteria.
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Affiliation(s)
- Jesús Cámara-Almirón
- a Instituto de Hortofruticultura Subtropical y Mediterránea ''La Mayora'' - Departamento de Microbiología , Universidad de Málaga , Málaga , Spain
| | - Joaquin Caro-Astorga
- a Instituto de Hortofruticultura Subtropical y Mediterránea ''La Mayora'' - Departamento de Microbiología , Universidad de Málaga , Málaga , Spain
| | - Antonio de Vicente
- a Instituto de Hortofruticultura Subtropical y Mediterránea ''La Mayora'' - Departamento de Microbiología , Universidad de Málaga , Málaga , Spain
| | - Diego Romero
- a Instituto de Hortofruticultura Subtropical y Mediterránea ''La Mayora'' - Departamento de Microbiología , Universidad de Málaga , Málaga , Spain
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55
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Penney J, Li J. Protegrin 1 Enhances Innate Cellular Defense via the Insulin-Like Growth Factor 1 Receptor Pathway. Front Cell Infect Microbiol 2018; 8:331. [PMID: 30324092 PMCID: PMC6173103 DOI: 10.3389/fcimb.2018.00331] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 08/28/2018] [Indexed: 11/13/2022] Open
Abstract
Antimicrobial peptides (AMPs) represent a promising area of research to help combat the ever-growing problem of antibiotic resistance. Protegrin-1 is an AMP from the cathelicidin family. It is produced naturally in pigs and its mature form (mPG-1) has potent bactericidal properties and a unique β-hairpin structure that separates it from most AMPs found in mice and humans. While the antibacterial properties of protegrin-1 are well established, the role it plays in immune modulation has yet to be investigated, and our current study sought to explore this alternate role and potential mechanism behind. We found that mPG-1 stimulated intestinal cell migration, this is accompanied with altered expression of genes associated with cell migration, in addition to increased expression of pro-inflammatory cytokines and immune-related factors. Further study suggested that mPG-1 activates insulin-like growth factor 1 receptor (IGF1R) and through this receptor it modulates immune activity as well as cell migration. Our study revealed a novel function of mPG-1, and its associated pathway, suggesting therapeutic potential of the antimicrobial peptide for infection and/or immune disorders, particularly ones affecting the gastrointestinal tract such as inflammatory bowel syndrome.
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Affiliation(s)
- Jenna Penney
- Department of Life Science and Engineering, Foshan University, Foshan Shi, China.,Department of Animal Bioscience, University of Guelph, Guelph, ON, Canada
| | - Julang Li
- Department of Life Science and Engineering, Foshan University, Foshan Shi, China.,Department of Animal Bioscience, University of Guelph, Guelph, ON, Canada
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56
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Cereghetti G, Saad S, Dechant R, Peter M. Reversible, functional amyloids: towards an understanding of their regulation in yeast and humans. Cell Cycle 2018; 17:1545-1558. [PMID: 29963943 DOI: 10.1080/15384101.2018.1480220] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein aggregates, and in particular amyloids, are generally considered to be inherently irreversible aberrant clumps, and are often associated with pathologies, such as Alzheimer's disease, Parkinson's disease, or systemic amyloidosis. However, recent evidence demonstrates that some aggregates are not only fully reversible, but also perform essential physiological functions. Despite these new findings, very little is known about how these functional protein aggregates are regulated in a physiological context. Here, we take the yeast pyruvate kinase Cdc19 as an example of a protein forming functional, reversible, solid, amyloid-like aggregates in response to stress conditions. Cdc19 aggregation is regulated via an aggregation-prone low complexity region (LCR). In favorable growth conditions, this LCR is prevented from aggregating by phosphorylation or oligomerization, while upon glucose starvation it becomes exposed and allows aggregation. We suggest that LCR phosphorylation, oligomerization or partner-binding may be general and widespread mechanisms regulating LCR-mediated reversible protein aggregation. Moreover, we show that, as predicted by computational tools, Cdc19 forms amyloid-like aggregates in vitro. Interestingly, we also observe striking similarities between Cdc19 and its mammalian counterpart, PKM2. Indeed, also PKM2 harbors a LCR and contains several peptides with high amyloidogenic propensity, which coincide with known phosphorylation sites. Thus, we speculate that the formation of reversible, amyloid-like aggregates may be a general physiological mechanism for cells to adapt to stress conditions, and that the underlying regulatory mechanisms may be conserved from yeast to humans.
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Affiliation(s)
- Gea Cereghetti
- a Institute of Biochemistry, Department of Biology , ETH Zürich , Zürich , Switzerland.,b Life Science Zürich , Molecular Life Sciences , Zürich , Switzerland
| | - Shady Saad
- c Department of Chemical and Systems Biology , Stanford University , Stanford, CA , USA
| | - Reinhard Dechant
- a Institute of Biochemistry, Department of Biology , ETH Zürich , Zürich , Switzerland
| | - Matthias Peter
- a Institute of Biochemistry, Department of Biology , ETH Zürich , Zürich , Switzerland
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57
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Martin LL, Kubeil C, Piantavigna S, Tikkoo T, Gray NP, John T, Calabrese AN, Liu Y, Hong Y, Hossain MA, Patil N, Abel B, Hoffmann R, Bowie JH, Carver JA. Amyloid aggregation and membrane activity of the antimicrobial peptide uperin 3.5. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24052] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Clemens Kubeil
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
| | | | - Tarun Tikkoo
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
| | - Nicholas P. Gray
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
| | - Torsten John
- School of Chemistry; Monash University; Clayton Victoria 3800 Australia
- Leibniz Institute of Surface Engineering (IOM) and Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry; Leipzig University; Leipzig 04318 Germany
| | - Antonio N. Calabrese
- Department of Chemistry and School of Physical Sciences; The University of Adelaide; Adelaide South Australia 5005 Australia
| | - Yanqin Liu
- Department of Chemistry and School of Physical Sciences; The University of Adelaide; Adelaide South Australia 5005 Australia
| | - Yuning Hong
- Department of Chemistry and Physics; La Trobe Institute for Molecular Science, La Trobe University; Melbourne Victoria 3086 Australia
| | - Mohammed A. Hossain
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne; Parkville Victoria 3010 Australia
| | - Nitin Patil
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne; Parkville Victoria 3010 Australia
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM) and Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry; Leipzig University; Leipzig 04318 Germany
| | - Ralf Hoffmann
- Institute of Bioanalytical Chemistry, and Center for Biotechnology and Biomedicine (BBZ), Universität Leipzig; Leipzig 04103 Germany
| | - John H. Bowie
- Department of Chemistry and School of Physical Sciences; The University of Adelaide; Adelaide South Australia 5005 Australia
| | - John A. Carver
- Research School of Chemistry; The Australian National University; Acton Australian Capital Territory 2601 Australia
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58
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Schnaider L, Brahmachari S, Schmidt NW, Mensa B, Shaham-Niv S, Bychenko D, Adler-Abramovich L, Shimon LJW, Kolusheva S, DeGrado WF, Gazit E. Self-assembling dipeptide antibacterial nanostructures with membrane disrupting activity. Nat Commun 2017; 8:1365. [PMID: 29118336 PMCID: PMC5678095 DOI: 10.1038/s41467-017-01447-x] [Citation(s) in RCA: 249] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 09/19/2017] [Indexed: 01/08/2023] Open
Abstract
Peptide-based supramolecular assemblies are a promising class of nanomaterials with important biomedical applications, specifically in drug delivery and tissue regeneration. However, the intrinsic antibacterial capabilities of these assemblies have been largely overlooked. The recent identification of common characteristics shared by antibacterial and self-assembling peptides provides a paradigm shift towards development of antibacterial agents. Here we present the antibacterial activity of self-assembled diphenylalanine, which emerges as the minimal model for antibacterial supramolecular polymers. The diphenylalanine nano-assemblies completely inhibit bacterial growth, trigger upregulation of stress-response regulons, induce substantial disruption to bacterial morphology, and cause membrane permeation and depolarization. We demonstrate the specificity of these membrane interactions and the development of antibacterial materials by integration of the peptide assemblies into tissue scaffolds. This study provides important insights into the significance of the interplay between self-assembly and antimicrobial activity and establishes innovative design principles toward the development of antimicrobial agents and materials. Peptide-based supramolecular assemblies are a promising class of nanomaterials with important biomedical applications, but their antibacterial properties can be overlooked. Here the authors show the antibacterial activity of self-assembled diphenylalanine, which emerges as the minimal model for antibacterial supramolecular polymers.
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Affiliation(s)
- Lee Schnaider
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Sayanti Brahmachari
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Nathan W Schmidt
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA, 94158, USA
| | - Bruk Mensa
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA, 94158, USA
| | - Shira Shaham-Niv
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Darya Bychenko
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Lihi Adler-Abramovich
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Linda J W Shimon
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Sofiya Kolusheva
- Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva, 84105, Israel
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA, 94158, USA.
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel. .,Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, 69978, Israel.
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59
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Jackson MP, Hewitt EW. Why are Functional Amyloids Non-Toxic in Humans? Biomolecules 2017; 7:biom7040071. [PMID: 28937655 PMCID: PMC5745454 DOI: 10.3390/biom7040071] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 12/26/2022] Open
Abstract
Amyloids were first identified in association with amyloidoses, human diseases in which proteins and peptides misfold into amyloid fibrils. Subsequent studies have identified an array of functional amyloid fibrils that perform physiological roles in humans. Given the potential for the production of toxic species in amyloid assembly reactions, it is remarkable that cells can produce these functional amyloids without suffering any obvious ill effect. Although the precise mechanisms are unclear, there are a number of ways in which amyloid toxicity may be prevented. These include regulating the level of the amyloidogenic peptides and proteins, minimising the production of prefibrillar oligomers in amyloid assembly reactions, sequestrating amyloids within membrane bound organelles, controlling amyloid assembly by other molecules, and disassembling the fibrils under physiological conditions. Crucially, a better understanding of how toxicity is avoided in the production of functional amyloids may provide insights into the prevention of amyloid toxicity in amyloidoses.
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Affiliation(s)
- Matthew P Jackson
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Eric W Hewitt
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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60
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Drolle E, Negoda A, Hammond K, Pavlov E, Leonenko Z. Changes in lipid membranes may trigger amyloid toxicity in Alzheimer's disease. PLoS One 2017; 12:e0182194. [PMID: 28767712 PMCID: PMC5540602 DOI: 10.1371/journal.pone.0182194] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/13/2017] [Indexed: 12/16/2022] Open
Abstract
Amyloid-beta peptides (Aβ), implicated in Alzheimer’s disease (AD), interact with the cellular membrane and induce amyloid toxicity. The composition of cellular membranes changes in aging and AD. We designed multi-component lipid models to mimic healthy and diseased states of the neuronal membrane. Using atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM) and black lipid membrane (BLM) techniques, we demonstrated that these model membranes differ in their nanoscale structure and physical properties, and interact differently with Aβ1–42. Based on our data, we propose a new hypothesis that changes in lipid membrane due to aging and AD may trigger amyloid toxicity through electrostatic mechanisms, similar to the accepted mechanism of antimicrobial peptide action. Understanding the role of the membrane changes as a key activating amyloid toxicity may aid in the development of a new avenue for the prevention and treatment of AD.
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Affiliation(s)
- Elizabeth Drolle
- Department of Biology, University of Waterloo, Waterloo, Canada.,Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Canada
| | - Alexander Negoda
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
| | - Keely Hammond
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
| | - Evgeny Pavlov
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada.,Department of Basic Sciences, New York University College of Dentistry, New York, New York, United States of America
| | - Zoya Leonenko
- Department of Biology, University of Waterloo, Waterloo, Canada.,Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Canada.,Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
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61
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Harioudh MK, Sahai R, Mitra K, Ghosh JK. A short non-cytotoxic antimicrobial peptide designed from Aβ29-40 adopts a nanostructure and shows in vivo anti-endotoxin activity. Chem Commun (Camb) 2017; 53:13079-13082. [DOI: 10.1039/c7cc07547b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A schematic presentation of the plausible mechanism of antimicrobial activities of Aβ29-40-V2 and Aβ29-40-V4.
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Affiliation(s)
- Munesh Kumar Harioudh
- Molecular and Structural Biology Division
- CSIR-Central Drug Research Institute
- Lucknow-226031
- India
| | - Rohit Sahai
- Electron Microscopy Unit
- CSIR-Central Drug Research Institute
- Lucknow-226031
- India
| | - Kalyan Mitra
- Electron Microscopy Unit
- CSIR-Central Drug Research Institute
- Lucknow-226031
- India
| | - Jimut Kanti Ghosh
- Molecular and Structural Biology Division
- CSIR-Central Drug Research Institute
- Lucknow-226031
- India
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62
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Sayegh RSR, Batista IDFC, de Melo RL, Riske KA, Daffre S, Montich G, da Silva Junior PI. Longipin: An Amyloid Antimicrobial Peptide from the Harvestman Acutisoma longipes (Arachnida: Opiliones) with Preferential Affinity for Anionic Vesicles. PLoS One 2016; 11:e0167953. [PMID: 27997568 PMCID: PMC5172563 DOI: 10.1371/journal.pone.0167953] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 11/22/2016] [Indexed: 12/24/2022] Open
Abstract
In contrast to vertebrate immune systems, invertebrates lack an adaptive response and rely solely on innate immunity in which antimicrobial peptides (AMPs) play an essential role. Most of them are membrane active molecules that are typically unstructured in solution and adopt secondary/tertiary structures upon binding to phospholipid bilayers. This work presents the first characterization of a constitutive AMP from the hemolymph of an Opiliones order animal: the harvestman Acutisoma longipes. This peptide was named longipin. It presents 18 aminoacid residues (SGYLPGKEYVYKYKGKVF) and a positive net charge at neutral pH. No similarity with other AMPs was observed. However, high sequence similarity with heme-lipoproteins from ticks suggested that longipin might be a protein fragment. The synthetic peptide showed enhanced antifungal activity against Candida guilliermondii and C. tropicalis yeasts (MIC: 3.8–7.5 μM) and did not interfered with VERO cells line viability at all concentrations tested (200–0.1 μM). This selectivity against microbial cells is related to the highest affinity of longipin for anionic charged vesicles (POPG:POPC) compared to zwitterionic ones (POPC), once microbial plasma membrane are generally more negatively charged compared to mammalian cells membrane. Dye leakage from carboxyfluorescein-loaded POPG:POPC vesicles suggested that longipin is a membrane active antimicrobial peptide and FT-IR spectroscopy showed that the peptide chain is mainly unstructured in solution or in the presence of POPC vesicles. However, upon binding to POPG:POPC vesicles, the FT-IR spectrum showed bands related to β-sheet and amyloid-like fibril conformations in agreement with thioflavin-T binding assays, indicating that longipin is an amyloid antimicrobial peptide.
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Affiliation(s)
- Raphael Santa Rosa Sayegh
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, Brazil
- * E-mail: (RSSS); (PISJ)
| | - Isabel de Fátima Correia Batista
- Unidade de Sequenciamento de Proteínas e Peptídeos, Instituto Butantan, São Paulo, Brazil
- Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo, Brazil
| | - Robson Lopes de Melo
- Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, Brazil
| | - Karin A. Riske
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Sirlei Daffre
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Guillermo Montich
- Centro de Investigaciones en Quimica Biológica de Córdoba (CIQUIBIC, UNC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Pedro Ismael da Silva Junior
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, Brazil
- * E-mail: (RSSS); (PISJ)
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63
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Mechanical properties that influence antimicrobial peptide activity in lipid membranes. Appl Microbiol Biotechnol 2016; 100:10251-10263. [DOI: 10.1007/s00253-016-7975-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 01/22/2023]
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64
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Oligomerization of the antimicrobial peptide Protegrin-5 in a membrane-mimicking environment. Structural studies by high-resolution NMR spectroscopy. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 46:293-300. [PMID: 27589857 DOI: 10.1007/s00249-016-1167-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/23/2016] [Accepted: 08/26/2016] [Indexed: 10/21/2022]
Abstract
Protegrin pore formation is believed to occur in a stepwise fashion that begins with a nonspecific peptide interaction with the negatively charged bacterial cell walls via hydrophobic and positively charged amphipathic surfaces. There are five known nature protegrins (PG1-PG5), and early studies of PG-1 (PDB ID:1PG1) shown that it could form antiparallel dimer in membrane mimicking environment which could be a first step for further oligomeric membrane pore formation. Later, we solved PG-2 (PDB ID:2MUH) and PG-3 (PDB ID:2MZ6) structures in the same environment and for PG-3 observed a strong dαα NOE effects between residues R18 and F12, V14, and V16. These "inconsistent" with monomer structure NOEs appears due to formation of an additional antiparallel β-sheet between two monomers. It was also suggested that there is a possible association of protegrins dimers to form octameric or decameric β-barrels in an oligomer state. In order to investigate a more detailed oligomerization process of protegrins, in the present article we report the monomer (PDB ID: 2NC7) and octamer pore structures of the protegrin-5 (PG-5) in the presence of DPC micelles studied by solution NMR spectroscopy. In contrast to PG-1, PG-2, and PG-3 studies, for PG-5 we observed not only dimer NOEs but also several additional NOEs between side chains, which allows us to calculate an octamer pore structure of PG-5 that was in good agreement with previous AFM and PMF data.
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65
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Wang CK, King GJ, Conibear AC, Ramos MC, Chaousis S, Henriques ST, Craik DJ. Mirror Images of Antimicrobial Peptides Provide Reflections on Their Functions and Amyloidogenic Properties. J Am Chem Soc 2016; 138:5706-13. [PMID: 27064294 DOI: 10.1021/jacs.6b02575] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Enantiomeric forms of BTD-2, PG-1, and PM-1 were synthesized to delineate the structure and function of these β-sheet antimicrobial peptides. Activity and lipid-binding assays confirm that these peptides act via a receptor-independent mechanism involving membrane interaction. The racemic crystal structure of BTD-2 solved at 1.45 Å revealed a novel oligomeric form of β-sheet antimicrobial peptides within the unit cell: an antiparallel trimer, which we suggest might be related to its membrane-active form. The BTD-2 oligomer extends into a larger supramolecular state that spans the crystal lattice, featuring a steric-zipper motif that is common in structures of amyloid-forming peptides. The supramolecular structure of BTD-2 thus represents a new mode of fibril-like assembly not previously observed for antimicrobial peptides, providing structural evidence linking antimicrobial and amyloid peptides.
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Affiliation(s)
- Conan K Wang
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Gordon J King
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Anne C Conibear
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Mariana C Ramos
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Stephanie Chaousis
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland , Brisbane, Queensland 4072, Australia
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66
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Zughaier SM, Svoboda P, Pohl J. Structure-Dependent Immune Modulatory Activity of Protegrin-1 Analogs. Antibiotics (Basel) 2016; 3:694-713. [PMID: 26097747 PMCID: PMC4472440 DOI: 10.3390/antibiotics3040694] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Protegrins are porcine antimicrobial peptides (AMPs) that belong to the cathelicidin family of host defense peptides. Protegrin-1 (PG-1), the most investigated member of the protegrin family, is an arginine-rich peptide consisting of 18 amino acid residues, its main chain adopting a β-hairpin structure that is linked by two disulfide bridges. We report on the immune modulatory activity of PG-1 and its analogs in neutralizing bacterial endotoxin and capsular polysaccharides, consequently inhibiting inflammatory mediators’ release from macrophages. We demonstrate that the β-hairpin structure motif stabilized with at least one disulfide bridge is a prerequisite for the immune modulatory activity of this type of AMP.
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Affiliation(s)
- Susu M. Zughaier
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Laboratories of Microbial Pathogenesis, Atlanta Department of Veterans Affairs Medical Center, Atlanta, GA 30033, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-404-321-6111 (ext. 12461); Fax: +1-404-329-2210
| | - Pavel Svoboda
- Microchemical and Proteomics Facility, Emory University School of Medicine, Atlanta, GA 30322, USA; E-Mails: (P.S.); (J.P.)
- Biotechnology Core Facility Branch, Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Jan Pohl
- Microchemical and Proteomics Facility, Emory University School of Medicine, Atlanta, GA 30322, USA; E-Mails: (P.S.); (J.P.)
- Biotechnology Core Facility Branch, Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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67
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Gour S, Kaushik V, Kumar V, Bhat P, Yadav SC, Yadav JK. Antimicrobial peptide (Cn-AMP2) from liquid endosperm ofCocos nuciferaforms amyloid-like fibrillar structure. J Pept Sci 2016; 22:201-7. [DOI: 10.1002/psc.2860] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 12/15/2015] [Accepted: 01/04/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Shalini Gour
- Department of Biotechnology; Central University of Rajasthan; Bandersindri NH-8 Jaipur-Ajmer Highway, Dist. Ajmer 305 801 Rajasthan India
| | - Vibha Kaushik
- Department of Biotechnology; Central University of Rajasthan; Bandersindri NH-8 Jaipur-Ajmer Highway, Dist. Ajmer 305 801 Rajasthan India
| | - Vijay Kumar
- Department of Biotechnology; Central University of Rajasthan; Bandersindri NH-8 Jaipur-Ajmer Highway, Dist. Ajmer 305 801 Rajasthan India
| | - Priyanka Bhat
- Department of Biotechnology; Central University of Rajasthan; Bandersindri NH-8 Jaipur-Ajmer Highway, Dist. Ajmer 305 801 Rajasthan India
| | - Subhash C. Yadav
- Department of Anatomy; All India Institute of Medical Sciences; New Delhi -110029 India
| | - Jay K. Yadav
- Department of Biotechnology; Central University of Rajasthan; Bandersindri NH-8 Jaipur-Ajmer Highway, Dist. Ajmer 305 801 Rajasthan India
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68
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Coya JM, Akinbi HT, Sáenz A, Yang L, Weaver TE, Casals C. Natural Anti-Infective Pulmonary Proteins: In Vivo Cooperative Action of Surfactant Protein SP-A and the Lung Antimicrobial Peptide SP-BN. THE JOURNAL OF IMMUNOLOGY 2015; 195:1628-36. [PMID: 26163587 DOI: 10.4049/jimmunol.1500778] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/10/2015] [Indexed: 12/19/2022]
Abstract
The anionic antimicrobial peptide SP-B(N), derived from the N-terminal saposin-like domain of the surfactant protein (SP)-B proprotein, and SP-A are lung anti-infective proteins. SP-A-deficient mice are more susceptible than wild-type mice to lung infections, and bacterial killing is enhanced in transgenic mice overexpressing SP-B(N). Despite their potential anti-infective action, in vitro studies indicate that several microorganisms are resistant to SP-A and SP-B(N). In this study, we test the hypothesis that these proteins act synergistically or cooperatively to strengthen each other's microbicidal activity. The results indicate that the proteins acted synergistically in vitro against SP-A- and SP-B(N)-resistant capsulated Klebsiella pneumoniae (serotype K2) at neutral pH. SP-A and SP-B(N) were able to interact in solution (Kd = 0.4 μM), which enabled their binding to bacteria with which SP-A or SP-B(N) alone could not interact. In vivo, we found that treatment of K. pneumoniae-infected mice with SP-A and SP-B(N) conferred more protection against K. pneumoniae infection than each protein individually. SP-A/SP-B(N)-treated infected mice showed significant reduction of bacterial burden, enhanced neutrophil recruitment, and ameliorated lung histopathology with respect to untreated infected mice. In addition, the concentrations of inflammatory mediators in lung homogenates increased early in infection in contrast with the weak inflammatory response of untreated K. pneumoniae-infected mice. Finally, we found that therapeutic treatment with SP-A and SP-B(N) 6 or 24 h after bacterial challenge conferred significant protection against K. pneumoniae infection. These studies show novel anti-infective pathways that could drive development of new strategies against pulmonary infections.
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Affiliation(s)
- Juan Manuel Coya
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain; and
| | - Henry T Akinbi
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Alejandra Sáenz
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain; and
| | - Li Yang
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Timothy E Weaver
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Cristina Casals
- Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain; and
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69
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Usachev KS, Efimov SV, Kolosova OA, Filippov AV, Klochkov VV. High-resolution NMR structure of the antimicrobial peptide protegrin-2 in the presence of DPC micelles. JOURNAL OF BIOMOLECULAR NMR 2015; 61:227-34. [PMID: 25430060 DOI: 10.1007/s10858-014-9885-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/20/2014] [Indexed: 05/22/2023]
Abstract
PG-1 adopts a dimeric structure in dodecylphosphocholine (DPC) micelles, and a channel is formed by the association of several dimers but the molecular mechanisms of the membrane damage by non-α-helical peptides are still unknown. The formation of the PG-1 dimer is important for pore formation in the lipid bilayer, since the dimer can be regarded as the primary unit for assembly into the ordered aggregates. It was supposed that only 12 residues (RGGRL-CYCRR-RFCVC-V) are needed to endow protegrin molecules with strong antibacterial activity and that at least four additional residues are needed to add potent antifungal properties. Thus, the 16-residue protegrin (PG-2) represents the minimal structure needed for broad-spectrum antimicrobial activity encompassing bacteria and fungi. As the peptide conformation and peptide-to-membrane binding properties are very sensitive to single amino acid substitutions, the solution structure of PG-2 in solution and in a membrane mimicking environment are crucial. In order to find evidence if the oligomerization state of PG-1 in a lipid environment will be the same or not for another protegrins, we investigate in the present work the PG-2 NMR solution structure in the presence of perdeuterated DPC micelles. The NMR study reported in the present work indicates that PG-2 form a well-defined structure (PDB: 2MUH) composed of a two-stranded antiparallel β-sheet when it binds to DPC micelles.
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Affiliation(s)
- K S Usachev
- Kazan Federal University, Kremlevskaya, 18, Kazan, 420008, Russian Federation,
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70
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Zhang M, Zhao J, Zheng J. Molecular understanding of a potential functional link between antimicrobial and amyloid peptides. SOFT MATTER 2014; 10:7425-7451. [PMID: 25105988 DOI: 10.1039/c4sm00907j] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Antimicrobial and amyloid peptides do not share common sequences, typical secondary structures, or normal biological activity but both the classes of peptides exhibit membrane-disruption ability to induce cell toxicity. Different membrane-disruption mechanisms have been proposed for antimicrobial and amyloid peptides, individually, some of which are not exclusive to either peptide type, implying that certain common principles may govern the folding and functions of different cytolytic peptides and associated membrane disruption mechanisms. Particularly, some antimicrobial and amyloid peptides have been identified to have dual complementary amyloid and antimicrobial properties, suggesting a potential functional link between amyloid and antimicrobial peptides. Given that some similar structural and membrane-disruption characteristics exist between the two classes of peptides, this review summarizes major findings, recent advances, and future challenges related to antimicrobial and amyloid peptides and strives to illustrate the similarities, differences, and relationships in the sequences, structures, and membrane interaction modes between amyloid and antimicrobial peptides, with a special focus on direct interactions of the peptides with the membranes. We hope that this review will stimulate further research at the interface of antimicrobial and amyloid peptides - which has been studied less intensively than either type of peptides - to decipher a possible link between both amyloid pathology and antimicrobial activity, which can guide drug design and peptide engineering to influence peptide-membrane interactions important in human health and diseases.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.
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71
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Poojari C, Xiao D, Batista VS, Strodel B. Membrane permeation induced by aggregates of human islet amyloid polypeptides. Biophys J 2014; 105:2323-32. [PMID: 24268144 DOI: 10.1016/j.bpj.2013.09.045] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 09/12/2013] [Accepted: 09/30/2013] [Indexed: 01/23/2023] Open
Abstract
Several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases as well as nonneuropathic diseases such as type II diabetes and atrial amyloidosis are associated with aggregation of amyloid polypeptides into fibrillar structures, or plaques. In this study, we use molecular dynamics simulations to test the stability and orientation of membrane-embedded aggregates of the human islet amyloid polypeptide (hIAPP) implicated in type II diabetes. We find that in both monolayers and bilayers of dipalmitoylphosphatidylglycerol (DPPG) hIAPP trimers and tetramers remain inside the membranes and preserve their β-sheet secondary structure. Lipid bilayer-inserted hIAPP trimers and tetramers orient inside DPPG at 60° relative to the membrane/water interface and lead to water permeation and Na(+) intrusion, consistent with ion-toxicity in islet β-cells. In particular, hIAPP trimers form a water-filled β-sandwich that induce water permeability comparable with channel-forming proteins, such as aquaporins and gramicidin-A. The predicted disruptive orientation is consistent with the amphiphilic properties of the hIAPP aggregates and could be probed by chiral sum frequency generation (SFG) spectroscopy, as predicted by the simulated SFG spectra.
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Affiliation(s)
- Chetan Poojari
- Forschungszentrum Jülich GmbH, Institute of Complex Systems: Structural Biochemistry (ICS-6), 52425 Jülich, Germany
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72
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Gillman AL, Jang H, Lee J, Ramachandran S, Kagan B, Nussinov R, Teran Arce F. Activity and architecture of pyroglutamate-modified amyloid-β (AβpE3-42) pores. J Phys Chem B 2014; 118:7335-44. [PMID: 24922585 PMCID: PMC4096221 DOI: 10.1021/jp5040954] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 06/10/2014] [Indexed: 12/17/2022]
Abstract
Among the family of Aβ peptides, pyroglutamate-modified Aβ (AβpE) peptides are particularly associated with cytotoxicity in Alzheimer's disease (AD). They represent the dominant fraction of Aβ oligomers in the brains of AD patients, but their accumulation in the brains of elderly individuals with normal cognition is significantly lower. Accumulation of AβpE plaques precedes the formation of plaques of full-length Aβ (Aβ1-40/42). Most of these properties appear to be associated with the higher hydrophobicity of AβpE as well as an increased resistance to enzymatic degradation. However, the important question of whether AβpE peptides induce pore activity in lipid membranes and their potential toxicity compared with other Aβ pores is still open. Here we examine the activity of AβpE pores in anionic membranes using planar bilayer electrical recording and provide their structures using molecular dynamics simulations. We find that AβpE pores spontaneously induce ionic current across the membrane and have some similar properties to the other previously studied pores of the Aβ family. However, there are also some significant differences. The onset of AβpE3-42 pore activity is generally delayed compared with Aβ1-42 pores. However, once formed, AβpE3-42 pores produce increased ion permeability of the membrane, as indicated by a greater occurrence of higher conductance electrical events. Structurally, the lactam ring of AβpE peptides induces a change in the conformation of the N-terminal strands of the AβpE3-42 pores. While the N-termini of wild-type Aβ1-42 peptides normally reside in the bulk water region, the N-termini of AβpE3-42 peptides tend to reside in the hydrophobic lipid core. These studies provide a first step to an understanding of the enhanced toxicity attributed to AβpE peptides.
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Affiliation(s)
- Alan L. Gillman
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
| | - Hyunbum Jang
- Cancer
and Inflammation Program, National Cancer Institute at Frederick,
Leidos Biomedical Research, Inc., Frederick
National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Joon Lee
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Srinivasan Ramachandran
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Bruce
L. Kagan
- Department
of Psychiatry, David Geffen School of Medicine, Semel Institute for
Neuroscience and Human Behavior, University
of California, 760 Westwood
Plaza, Los Angeles, California 90024, United States
| | - Ruth Nussinov
- Cancer
and Inflammation Program, National Cancer Institute at Frederick,
Leidos Biomedical Research, Inc., Frederick
National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
- Department
of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fernando Teran Arce
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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73
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Landreh M, Johansson J, Jörnvall H. Separate molecular determinants in amyloidogenic and antimicrobial peptides. J Mol Biol 2014; 426:2159-66. [PMID: 24650898 DOI: 10.1016/j.jmb.2014.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/17/2014] [Accepted: 03/06/2014] [Indexed: 10/25/2022]
Abstract
Several amyloid-forming and antimicrobial peptides (AMYs and AMPs) have the ability to bind to and damage cell membranes. In addition, some AMYs possess antimicrobial activity and some AMPs form amyloid-like fibrils, relating the two peptide types and their properties. However, a comparison of their sequence characteristics reveals important differences. The high β-strand and aggregation propensities typical of AMYs are largely absent in α-helix-forming AMPs, which are instead marked by a strong amphipathic moment not generally found in AMYs. Although a few peptides, for example, islet amyloid polypeptide and dermaseptin S9, combine some determinants of both groups, the structural distinctions suggest that antimicrobial activity and amyloid formation are separate features not generally associated.
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Affiliation(s)
- Michael Landreh
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
| | - Jan Johansson
- KI Alzheimer's Disease Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, S-141 86 Stockholm, Sweden; Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-751 23 Uppsala, Sweden
| | - Hans Jörnvall
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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74
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Drolle E, Hane F, Lee B, Leonenko Z. Atomic force microscopy to study molecular mechanisms of amyloid fibril formation and toxicity in Alzheimer's disease. Drug Metab Rev 2014; 46:207-23. [PMID: 24495298 DOI: 10.3109/03602532.2014.882354] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease characterized by dementia and memory loss for which no cure or effective prevention is currently available. Neurodegeneration in AD is linked to formation of amyloid plaques found in brain tissues of Alzheimer's patients during post-mortem examination. Amyloid plaques are composed of amyloid fibrils and small oligomers - insoluble protein aggregates. Although amyloid plaques are found on the neuronal cell surfaces, the mechanism of amyloid toxicity is still not well understood. Currently, it is believed that the cytotoxicity is a result of the nonspecific interaction of small soluble amyloid oligomers (rather than longer fibrils) with the plasma membrane. In recent years, nanotechnology has contributed significantly to understanding the structure and function of lipid membranes and to the study of the molecular mechanisms of membrane-associated diseases. We review the current state of research, including applications of the latest nanotechnology approaches, on the interaction of lipid membranes with the amyloid-β (Aβ) peptide in relation to amyloid toxicity. We discuss the interactions of Aβ with model lipid membranes with a focus to demonstrate that composition, charge and phase of the lipid membrane, as well as lipid domains and rafts, affect the binding of Aβ to the membrane and contribute to toxicity. Understanding the role of the lipid membrane in AD at the nanoscale and molecular level will contribute to the understanding of the molecular mechanism of amyloid toxicity and may aid into the development of novel preventive strategies to combat AD.
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Affiliation(s)
- Elizabeth Drolle
- Department of Biology, University of Waterloo , Waterloo, ON , Canada
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75
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Poojari C, Strodel B. Stability of transmembrane amyloid β-peptide and membrane integrity tested by molecular modeling of site-specific Aβ42 mutations. PLoS One 2013; 8:e78399. [PMID: 24244308 PMCID: PMC3820573 DOI: 10.1371/journal.pone.0078399] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/11/2013] [Indexed: 11/20/2022] Open
Abstract
Interactions of the amyloid β-protein (Aβ) with neuronal cell membranes, leading to the disruption of membrane integrity, are considered to play a key role in the development of Alzheimer’s disease. Natural mutations in Aβ42, such as the Arctic mutation (E22G) have been shown to increase Aβ42 aggregation and neurotoxicity, leading to the early-onset of Alzheimer’s disease. A correlation between the propensity of Aβ42 to form protofibrils and its effect on neuronal dysfunction and degeneration has been established. Using rational mutagenesis of the Aβ42 peptide it was further revealed that the aggregation of different Aβ42 mutants in lipid membranes results in a variety of polymorphic aggregates in a mutation dependent manner. The mutant peptides also have a variable ability to disrupt bilayer integrity. To further test the connection between Aβ42 mutation and peptide–membrane interactions, we perform molecular dynamics simulations of membrane-inserted Aβ42 variants (wild-type and E22G, D23G, E22G/D23G, K16M/K28M and K16M/E22G/D23G/K28M mutants) as β-sheet monomers and tetramers. The effects of charged residues on transmembrane Aβ42 stability and membrane integrity are analyzed at atomistic level. We observe an increased stability for the E22G Aβ42 peptide and a decreased stability for D23G compared to wild-type Aβ42, while D23G has the largest membrane-disruptive effect. These results support the experimental observation that the altered toxicity arising from mutations in Aβ is not only a result of the altered aggregation propensity, but also originates from modified Aβ interactions with neuronal membranes.
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Affiliation(s)
- Chetan Poojari
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail:
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76
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Gupta K, Jang H, Harlen K, Puri A, Nussinov R, Schneider JP, Blumenthal R. Mechanism of membrane permeation induced by synthetic β-hairpin peptides. Biophys J 2013; 105:2093-103. [PMID: 24209854 PMCID: PMC3824417 DOI: 10.1016/j.bpj.2013.09.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/23/2013] [Accepted: 09/26/2013] [Indexed: 11/16/2022] Open
Abstract
We have investigated the membrane destabilizing properties of synthetic amphiphilic cationic peptides, MAX1 and MAX35, which have the propensity to form β-hairpin structures under certain conditions, and a control non-β-hairpin-forming peptide MAX8V16E. All three peptides bind to liposomes containing a mixture of zwitterionic POPC and negatively charged POPS lipids as determined by Zeta potential measurements. Circular dichroism measurements indicated folding of MAX1 and MAX35 in the presence of the POPC/POPS liposomes, whereas no such folding was observed with MAX8V16E. There was no binding or folding of these peptides to liposomes containing only POPC. MAX1 and MAX35 induced release of contents from negatively charged liposomes, whereas MAX8V16E failed to promote solute release under identical conditions. Thus, MAX1 and MAX35 bind to, and fold at the surface of negatively charged liposomes adopting a lytic conformation. We ruled out leaky fusion as a mechanism of release by including 2 mol % PEG-PE in the liposomes, which inhibits aggregation/fusion but not folding of MAX or MAX-induced leakage. Using a concentration-dependent quenching probe (calcein), we determined that MAX-induced leakage of liposome contents was an all-or-none process. At MAX1 concentrations, which cause release of ~50% of the liposomes that contain small (R(h) <1.5 nm) markers, only ~15% of those liposomes release a fluorescent dextran of 40 kDa. A multimeric model of the pore is presented based on these results. Atomistic molecular dynamics simulations show that barrels consisting of 10 β-hairpin MAX1 and MAX35 peptides are relatively more stable than MAX8V16E barrels in the bilayer, suggesting that barrels of this size are responsible for the peptides lytic action.
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Affiliation(s)
- Kshitij Gupta
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Hyunbum Jang
- Basic Science Program, SAIC-Frederick, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Kevin Harlen
- Peptide Design and Materials Section, Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Anu Puri
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Joel P. Schneider
- Peptide Design and Materials Section, Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Robert Blumenthal
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
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77
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Munyuki G, Jackson GE, Venter GA, Kövér KE, Szilágyi L, Rautenbach M, Spathelf BM, Bhattacharya B, van der Spoel D. β-Sheet Structures and Dimer Models of the Two Major Tyrocidines, Antimicrobial Peptides from Bacillus aneurinolyticus. Biochemistry 2013; 52:7798-806. [DOI: 10.1021/bi401363m] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gadzikano Munyuki
- Department
of Chemistry, University of Cape Town, P Bag X3, Rondebosch, Cape Town, South Africa 7701
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-751 24 Uppsala, Sweden
| | - Graham E. Jackson
- Department
of Chemistry, University of Cape Town, P Bag X3, Rondebosch, Cape Town, South Africa 7701
| | - Gerhard A. Venter
- Department
of Chemistry, University of Cape Town, P Bag X3, Rondebosch, Cape Town, South Africa 7701
| | - Katalin E. Kövér
- Department
of Chemistry, University of Debrecen, H-4010 Debrecen, Egyetem tér 1, Pf. 20, Hungary
| | - László Szilágyi
- Department
of Chemistry, University of Debrecen, H-4010 Debrecen, Egyetem tér 1, Pf. 20, Hungary
| | - Marina Rautenbach
- BIOPEP
Peptide group, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa 7600
| | - Barbara M. Spathelf
- BIOPEP
Peptide group, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa 7600
| | - Bhaswati Bhattacharya
- BIOPEP
Peptide group, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa 7600
| | - David van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-751 24 Uppsala, Sweden
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78
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Garvey M, Meehan S, Gras SL, Schirra HJ, Craik DJ, Van der Weerden NL, Anderson MA, Gerrard JA, Carver JA. A radish seed antifungal peptide with a high amyloid fibril-forming propensity. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1834:1615-23. [PMID: 23665069 DOI: 10.1016/j.bbapap.2013.04.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 04/12/2013] [Accepted: 04/29/2013] [Indexed: 11/24/2022]
Abstract
The amyloid fibril-forming ability of two closely related antifungal and antimicrobial peptides derived from plant defensin proteins has been investigated. As assessed by sequence analysis, thioflavin T binding, transmission electron microscopy, atomic force microscopy and X-ray fiber diffraction, a 19 amino acid fragment from the C-terminal region of Raphanus sativus antifungal protein, known as RsAFP-19, is highly amyloidogenic. Further, its fibrillar morphology can be altered by externally controlled conditions. Freezing and thawing led to amyloid fibril formation which was accompanied by loss of RsAFP-19 antifungal activity. A second, closely related antifungal peptide displayed no fibril-forming capacity. It is concluded that while fibril formation is not associated with the antifungal properties of these peptides, the peptide RsAFP-19 is of potential use as a controllable, highly amyloidogenic small peptide for investigating the structure of amyloid fibrils and their mechanism of formation.
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Affiliation(s)
- Megan Garvey
- School of Chemistry and Physics, The University of Adelaide, Adelaide, Australia
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79
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Last NB, Schlamadinger DE, Miranker AD. A common landscape for membrane-active peptides. Protein Sci 2013; 22:870-82. [PMID: 23649542 DOI: 10.1002/pro.2274] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 04/23/2013] [Accepted: 04/24/2013] [Indexed: 10/26/2022]
Abstract
Three families of membrane-active peptides are commonly found in nature and are classified according to their initial apparent activity. Antimicrobial peptides are ancient components of the innate immune system and typically act by disruption of microbial membranes leading to cell death. Amyloid peptides contribute to the pathology of diverse diseases from Alzheimer's to type II diabetes. Preamyloid states of these peptides can act as toxins by binding to and permeabilizing cellular membranes. Cell-penetrating peptides are natural or engineered short sequences that can spontaneously translocate across a membrane. Despite these differences in classification, many similarities in sequence, structure, and activity suggest that peptides from all three classes act through a small, common set of physical principles. Namely, these peptides alter the Brownian properties of phospholipid bilayers, enhancing the sampling of intrinsic fluctuations that include membrane defects. A complete energy landscape for such systems can be described by the innate membrane properties, differential partition, and the associated kinetics of peptides dividing between surface and defect regions of the bilayer. The goal of this review is to argue that the activities of these membrane-active families of peptides simply represent different facets of what is a shared energy landscape.
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Affiliation(s)
- Nicholas B Last
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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80
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Common mechanism unites membrane poration by amyloid and antimicrobial peptides. Proc Natl Acad Sci U S A 2013; 110:6382-7. [PMID: 23576726 DOI: 10.1073/pnas.1219059110] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Poration of bacterial membranes by antimicrobial peptides such as magainin 2 is a significant activity performed by innate immune systems. Pore formation by soluble forms of amyloid proteins such as islet amyloid polypeptide (IAPP) is implicated in cell death in amyloidoses. Similarities in structure and poration activity of these two systems suggest a commonality of mechanism. Here, we investigate and compare the mechanisms by which these peptides induce membrane leakage and bacterial cell death through the measurement of liposome leakage kinetics and bacterial growth inhibition. For both systems, leakage occurs through the nucleation-dependent formation of stable membrane pores. Remarkably, we observe IAPP and magainin 2 to be fully cross-cooperative in the induction of leakage and inhibition of bacterial growth. The effects are dramatic, with mixtures of these peptides showing activities >100-fold greater than simple sums of the activities of individual peptides. Direct protein-protein interactions cannot be the origin of cooperativity, as IAPP and its enantiomer D-IAPP are equally cross-cooperative. We conclude that IAPP and magainin 2 induce membrane leakage and cytotoxicity through a shared, cross-cooperative, tension-induced poration mechanism.
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81
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Semen-derived enhancer of viral infection (SEVI) binds bacteria, enhances bacterial phagocytosis by macrophages, and can protect against vaginal infection by a sexually transmitted bacterial pathogen. Antimicrob Agents Chemother 2013; 57:2443-50. [PMID: 23507280 DOI: 10.1128/aac.02464-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The semen-derived enhancer of viral infection (SEVI) is a positively charged amyloid fibril that is derived from a self-assembling proteolytic cleavage fragment of prostatic acid phosphatase (PAP(248-286)). SEVI efficiently facilitates HIV-1 infection in vitro, but its normal physiologic function remains unknown. In light of the fact that other amyloidogenic peptides have been shown to possess direct antibacterial activity, we investigated whether SEVI could inhibit bacterial growth. Neither SEVI fibrils nor the unassembled PAP(248-286) peptide had significant direct antibacterial activity in vitro. However, SEVI fibrils bound to both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Neisseria gonorrhoeae) bacteria, in a charge-dependent fashion. Furthermore, SEVI fibrils but not the monomeric PAP(248-286) peptide promoted bacterial aggregation and enhanced the phagocytosis of bacteria by primary human macrophages. SEVI also enhanced binding of bacteria to macrophages and the subsequent release of bacterially induced proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], and IL-1β). Finally, SEVI fibrils inhibited murine vaginal colonization with Neisseria gonorrhoeae. These findings demonstrate that SEVI has indirect antimicrobial activity and that this activity is dependent on both the cationic charge and the fibrillar nature of SEVI.
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82
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Li JJ, Yip CM. Super-resolved FT-IR spectroscopy: Strategies, challenges, and opportunities for membrane biophysics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2272-82. [PMID: 23500349 DOI: 10.1016/j.bbamem.2013.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 02/25/2013] [Indexed: 01/16/2023]
Abstract
Direct correlation of molecular conformation with local structure is critical to studies of protein- and peptide-membrane interactions, particularly in the context of membrane-facilitated aggregation, and disruption or disordering. Infrared spectroscopy has long been a mainstay for determining molecular conformation, following folding dynamics, and characterizing reactions. While tremendous advances have been made in improving the spectral and temporal resolution of infrared spectroscopy, it has only been with the introduction of scanned-probe techniques that exploit the raster-scanning tip as either a source, scattering tool, or measurement probe that researchers have been able to obtain sub-diffraction limit IR spectra. This review will examine the history of correlated scanned-probe IR spectroscopies, from their inception to their use in studies of molecular aggregates, membrane domains, and cellular structures. The challenges and opportunities that these platforms present for examining dynamic phenomena will be discussed. This article is part of a Special Issue entitled: FTIR in membrane proteins and peptide studies.
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Affiliation(s)
- Jessica J Li
- Department of Chemical Engineering and Applied Chemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada M5S 3E1
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83
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Poojari C, Kukol A, Strodel B. How the amyloid-β peptide and membranes affect each other: An extensive simulation study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:327-39. [DOI: 10.1016/j.bbamem.2012.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 11/24/2022]
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84
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Travkova OG, Brezesinski G. Adsorption of the antimicrobial peptide arenicin and its linear derivative to model membranes – A maximum insertion pressure study. Chem Phys Lipids 2013; 167-168:43-50. [DOI: 10.1016/j.chemphyslip.2013.01.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 01/26/2013] [Indexed: 11/25/2022]
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85
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Jang H, Connelly L, Arce FT, Ramachandran S, Kagan BL, Lal R, Nussinov R. Mechanisms for the Insertion of Toxic, Fibril-like β-Amyloid Oligomers into the Membrane. J Chem Theory Comput 2013; 9:822-833. [PMID: 23316126 PMCID: PMC3539805 DOI: 10.1021/ct300916f] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amyloid-β (Aβ) oligomers destabilize cellular ionic homeostasis, mediating Alzheimer's disease (AD). It is still unclear whether the mechanism (i) is mediated by cell surface receptors; (ii) is direct, with Aβ oligomers interacting with membrane lipids; or (iii) both mechanisms take place. Recent studies indicate that Aβ oligomers may act by either of the last two. Little is known about the oligomers' structures and how they spontaneously insert into the membrane. Using explicit solvent molecular dynamics (MD) simulations, we show that fibril-like Aβ(17-42) (p3) oligomer is capable of penetrating the membrane. Insertion is similar to that observed for protegrin-1 (PG-1), a cytolytic β-sheet-rich antimicrobial peptide (AMP). Both Aβ and PG-1 favor the amphipathic interface of the lipid bilayer in the early stage of interaction with the membrane. U-shaped Aβ oligomers are observed in solution and in the membrane, suggesting that the preformed seeds can be shared by amyloid fibrils in the growth phase and membrane toxicity. Here we provide sequential events in possible Aβ oligomer membrane-insertion pathways. We speculate that for the U-shaped motif, a trimer is the minimal oligomer size to insert effectively. We propose that monomers and dimers may insert in (apparently on-pathway) aggregation-intermediate β-hairpin state, and may (or may not) convert to a U-shape in the bilayer. Together with earlier observations, our results point to a non-specific, broadly heterogeneous landscape of membrane-inserting oligomer conformations, pathways, and membrane-mediated toxicity of β-rich oligomers.
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Affiliation(s)
- Hyunbum Jang
- Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
| | - Laura Connelly
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Fernando Teran Arce
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Srinivasan Ramachandran
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Bruce L. Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, California 90024, USA
| | - Ratnesh Lal
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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86
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Torrent M, Pulido D, Nogués MV, Boix E. Exploring new biological functions of amyloids: bacteria cell agglutination mediated by host protein aggregation. PLoS Pathog 2012; 8:e1003005. [PMID: 23133388 PMCID: PMC3486885 DOI: 10.1371/journal.ppat.1003005] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 09/17/2012] [Indexed: 01/02/2023] Open
Abstract
Antimicrobial proteins and peptides (AMPs) are important effectors of the innate immune system that play a vital role in the prevention of infections. Recent advances have highlighted the similarity between AMPs and amyloid proteins. Using the Eosinophil Cationic Protein as a model, we have rationalized the structure-activity relationships between amyloid aggregation and antimicrobial activity. Our results show how protein aggregation can induce bacteria agglutination and cell death. Using confocal and total internal reflection fluorescence microscopy we have tracked the formation in situ of protein amyloid-like aggregates at the bacteria surface and on membrane models. In both cases, fibrillar aggregates able to bind to amyloid diagnostic dyes were detected. Additionally, a single point mutation (Ile13 to Ala) can suppress the protein amyloid behavior, abolishing the agglutinating activity and impairing the antimicrobial action. The mutant is also defective in triggering both leakage and lipid vesicle aggregation. We conclude that ECP aggregation at the bacterial surface is essential for its cytotoxicity. Hence, we propose here a new prospective biological function for amyloid-like aggregates with potential biological relevance. Microbial infections are reported among the worst human diseases and cause millions of deaths per year over the world. Antibiotics are used to treat infections and have saved more lives than any other drug in human history. However, due to extended use, many strains are becoming refractive to common antibiotics. In this light, new promising compounds, like antimicrobial proteins and peptides (AMPs) are being investigated. Some AMPs also show agglutinating activity; this is the ability to clump bacteria after treatment. This feature is particularly appealing because agglutinating peptides could be used to keep bacteria to the infection focus, helping microbe clearance by host immune cells. In this study, we propose a novel mechanism to explain agglutinating activity at a molecular level using Eosinophil Cationic Protein. We show that the agglutinating mechanism is driven by the protein amyloid-like aggregation at the bacteria cell surface. Accordingly, elimination of the amyloid behavior abolishes both the agglutinating and the antimicrobial activities. This study provides a new concept on how Nature could exploit amyloid-like aggregates to fight bacterial infections. Moreover, these results could also add new insights in understanding the relation between infection and inflammation with dementia and amyloid-related diseases like Alzheimer.
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Affiliation(s)
- Marc Torrent
- Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.
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87
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DePas WH, Chapman MR. Microbial manipulation of the amyloid fold. Res Microbiol 2012; 163:592-606. [PMID: 23108148 PMCID: PMC3532741 DOI: 10.1016/j.resmic.2012.10.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/09/2012] [Indexed: 12/19/2022]
Abstract
Microbial biofilms are encased in a protein, DNA, and polysaccharide matrix that protects the community, promotes interactions with the environment, and helps cells adhere together. The protein component of these matrices is often a remarkably stable, β-sheet-rich polymer called amyloid. Amyloids form ordered, self-templating fibers that are highly aggregative, making them a valuable biofilm component. Some eukaryotic proteins inappropriately adopt the amyloid fold, and these misfolded protein aggregates disrupt normal cellular proteostasis, which can cause significant cytotoxicity. Indeed, until recently amyloids were considered solely the result of protein misfolding. However, research over the past decade has revealed how various organisms have capitalized on the amyloid fold by developing sophisticated biogenesis pathways that coordinate gene expression, protein folding, and secretion so that amyloid-related toxicities are minimized. How microbes manipulate amyloids, by augmenting their advantageous properties and by reducing their undesirable properties, will be the subject of this review.
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Affiliation(s)
- William H. DePas
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
| | - Matthew R. Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan LSA, 830 North University Ave., Ann Arbor, MI, 48109, USA
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88
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Anderluh G, Zerovnik E. Pore formation by human stefin B in its native and oligomeric states and the consequent amyloid induced toxicity. Front Mol Neurosci 2012; 5:85. [PMID: 22876218 PMCID: PMC3410518 DOI: 10.3389/fnmol.2012.00085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 07/17/2012] [Indexed: 11/13/2022] Open
Abstract
It is well documented that amyloid forming peptides and proteins interact with membranes and that this correlates with cytotoxicity. To introduce the theme we give a brief description of some amyloidogenic proteins and note their similarities with pore forming toxins (PFTs) and cell penetrating peptides. Human stefin B, a member of the family of cystatins, is an amyloidogenic protein in vitro. This review describes our studies of the interaction of stefin B oligomers and prefibrillar aggregates with model membranes leading to pore formation. We have studied the interaction between human stefin B and artificial membranes of various compositions. We also have prepared distinct sizes and morphologies of stefin B prefibrillar states and assessed their toxicity. Furthermore, we have measured electrical currents through pores formed by stefin B prefibrillar oligomers in a planar lipid bilayer setup. We finally discuss the possible functional and pathological significance of such pores formed by human stefin B.
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89
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Gößler-Schöfberger R, Hesser G, Reif MM, Friedmann J, Duscher B, Toca-Herrera JL, Oostenbrink C, Jilek A. A stereochemical switch in the aDrs model system, a candidate for a functional amyloid. Arch Biochem Biophys 2012; 522:100-6. [PMID: 22510364 PMCID: PMC3365241 DOI: 10.1016/j.abb.2012.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 03/18/2012] [Accepted: 04/04/2012] [Indexed: 11/21/2022]
Abstract
Amyloid fibrils are commonly observed to adopt multiple distinct morphologies, which eventually can have significantly different neurotoxicities, as e.g. demonstrated in case of the Alzheimer peptide. The architecture of amyloid deposits is apparently also determined by the stereochemistry of amino acids. Post-translational changes of the chirality of certain residues may thus be a factor in controlling the formation of functional or disease-related amyloids. Anionic dermaseptin (aDrs), an unusual peptide from the skin secretions of the frog Pachymedusa dacnicolor, assembles to amyloid-like fibrils in a pH-dependent manner, which could play a functional role in defense. aDrs can be enzymatically converted into the diastereomer [d-Leu2]-aDrs by an l/d-isomerase. EM and AFM on fibrils formed by these isomers have shown that their predominant morphology is controlled by the stereochemistry of residue 2, whereas kinetic and thermodynamic parameters of aggregation are barely affected. When fibrils were grown from preformed seeds, backbone stereochemistry rather than templating-effects apparently dominated the superstructural organization of the isomers. Interestingly, MD indicated small differences in the conformational propensities between the isomers. Our results demonstrate how d-amino acid substitutions could take active part in the formation of functional or disease-related amyloid. Moreover, these findings contribute to the development of amyloid-based nanomaterials.
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Affiliation(s)
| | - Günter Hesser
- CSNA Center for Surface- and Nanoanalytics, Johannes Kepler University Linz, Austria
| | - Maria M. Reif
- Institute for Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna, Austria
| | - Jacqueline Friedmann
- Laboratory of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna, Austria
| | | | - José Luis Toca-Herrera
- Laboratory of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna, Austria
| | - Chris Oostenbrink
- Institute for Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna, Austria
| | - Alexander Jilek
- Institute of Organic Chemistry, Johannes Kepler University Linz, Austria
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, Austria
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90
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Kagan BL, Jang H, Capone R, Arce FT, Ramachandran S, Lal R, Nussinov R. Antimicrobial properties of amyloid peptides. Mol Pharm 2012; 9:708-17. [PMID: 22081976 PMCID: PMC3297685 DOI: 10.1021/mp200419b] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
More than two dozen clinical syndromes known as amyloid diseases are characterized by the buildup of extended insoluble fibrillar deposits in tissues. These amorphous Congo red staining deposits known as amyloids exhibit a characteristic green birefringence and cross-β structure. Substantial evidence implicates oligomeric intermediates of amyloids as toxic species in the pathogenesis of these chronic disease states. A growing body of data has suggested that these toxic species form ion channels in cellular membranes causing disruption of calcium homeostasis, membrane depolarization, energy drainage, and in some cases apoptosis. Amyloid peptide channels exhibit a number of common biological properties including the universal U-shape β-strand-turn-β-strand structure, irreversible and spontaneous insertion into membranes, production of large heterogeneous single-channel conductances, relatively poor ion selectivity, inhibition by Congo red, and channel blockade by zinc. Recent evidence has suggested that increased amounts of amyloids not only are toxic to its host target cells but also possess antimicrobial activity. Furthermore, at least one human antimicrobial peptide, protegrin-1, which kills microbes by a channel-forming mechanism, has been shown to possess the ability to form extended amyloid fibrils very similar to those of classic disease-forming amyloids. In this paper, we will review the reported antimicrobial properties of amyloids and the implications of these discoveries for our understanding of amyloid structure and function.
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Affiliation(s)
- Bruce L. Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California, Los Angeles, California 90024, U.S.A
| | - Hyunbum Jang
- Center for Cancer Research Nanobiology Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702, U.S.A
| | - Ricardo Capone
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Fernando Teran Arce
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Srinivasan Ramachandran
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Ratnesh Lal
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Ruth Nussinov
- Center for Cancer Research Nanobiology Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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91
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Capone R, Jang H, Kotler SA, Connelly L, Teran Arce F, Ramachandran S, Kagan BL, Nussinov R, Lal R. All-d-Enantiomer of β-Amyloid Peptide Forms Ion Channels in Lipid Bilayers. J Chem Theory Comput 2012; 8:1143-1152. [PMID: 22423218 PMCID: PMC3302213 DOI: 10.1021/ct200885r] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is the most common type of senile dementia in aging populations. Amyloid β (Aβ)-mediated dysregulation of ionic homeostasis is the prevailing underlying mechanism leading to synaptic degeneration and neuronal death. Aβ-dependent ionic dysregulation most likely occurs either directly via unregulated ionic transport through the membrane or indirectly via Aβ binding to cell membrane receptors and subsequent opening of existing ion channels or transporters. Receptor binding is expected to involve a high degree of stereospecificity. Here, we investigated whether an Aβ peptide enantiomer, whose entire sequence consists of d-amino acids, can form ion-conducting channels; these channels can directly mediate Aβ effects even in the absence of receptor-peptide interactions. Using complementary approaches of planar lipid bilayer (PLB) electrophysiological recordings and molecular dynamics (MD) simulations, we show that the d-Aβ isomer exhibits ion conductance behavior in the bilayer indistinguishable from that described earlier for the l-Aβ isomer. The d isomer forms channel-like pores with heterogeneous ionic conductance similar to the l-Aβ isomer channels, and the d-isomer channel conductance is blocked by Zn(2+), a known blocker of l-Aβ isomer channels. MD simulations further verify formation of β-barrel-like Aβ channels with d- and l-isomers, illustrating that both d- and l-Aβ barrels can conduct cations. The calculated values of the single-channel conductance are approximately in the range of the experimental values. These findings are in agreement with amyloids forming Ca(2+) leaking, unregulated channels in AD, and suggest that Aβ toxicity is mediated through a receptor-independent, nonstereoselective mechanism.
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Affiliation(s)
- Ricardo Capone
- Departments of Bioengineering
and Mechanical and Aerospace Engineering and Material Science Program, University of California—San Diego, La Jolla,
California 92093, United States
| | - Hyunbum Jang
- Center for Cancer Research Nanobiology
Program, SAIC-Frederick, Incorporated,
NCI-Frederick, Frederick, Maryland 21702, United States
| | - Samuel A. Kotler
- Departments of Bioengineering
and Mechanical and Aerospace Engineering and Material Science Program, University of California—San Diego, La Jolla,
California 92093, United States
| | - Laura Connelly
- Departments of Bioengineering
and Mechanical and Aerospace Engineering and Material Science Program, University of California—San Diego, La Jolla,
California 92093, United States
| | - Fernando Teran Arce
- Departments of Bioengineering
and Mechanical and Aerospace Engineering and Material Science Program, University of California—San Diego, La Jolla,
California 92093, United States
| | - Srinivasan Ramachandran
- Departments of Bioengineering
and Mechanical and Aerospace Engineering and Material Science Program, University of California—San Diego, La Jolla,
California 92093, United States
| | - Bruce L. Kagan
- Department of Psychiatry, David
Geffen School of Medicine, Semel Institute for Neuroscience and Human
Behavior, University of California—Los Angeles, Los Angeles, California 90024, United States
| | - Ruth Nussinov
- Center for Cancer Research Nanobiology
Program, SAIC-Frederick, Incorporated,
NCI-Frederick, Frederick, Maryland 21702, United States
- Department of Human Molecular
Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ratnesh Lal
- Departments of Bioengineering
and Mechanical and Aerospace Engineering and Material Science Program, University of California—San Diego, La Jolla,
California 92093, United States
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Connelly L, Arce FT, Jang H, Capone R, Kotler SA, Ramachandran S, Kagan BL, Nussinov R, Lal R. Atomic force microscopy and MD simulations reveal pore-like structures of all-D-enantiomer of Alzheimer's β-amyloid peptide: relevance to the ion channel mechanism of AD pathology. J Phys Chem B 2012; 116:1728-35. [PMID: 22217000 PMCID: PMC4342054 DOI: 10.1021/jp2108126] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is a protein misfolding disease characterized by a buildup of β-amyloid (Aβ) peptide as senile plaques, uncontrolled neurodegeneration, and memory loss. AD pathology is linked to the destabilization of cellular ionic homeostasis and involves Aβ peptide-plasma membrane interactions. In principle, there are two possible ways through which disturbance of the ionic homeostasis can take place: directly, where the Aβ peptide either inserts into the membrane and creates ion-conductive pores or destabilizes the membrane organization, or, indirectly, where the Aβ peptide interacts with existing cell membrane receptors. To distinguish between these two possible types of Aβ-membrane interactions, we took advantage of the biochemical tenet that ligand-receptor interactions are stereospecific; L-amino acid peptides, but not their D-counterparts, bind to cell membrane receptors. However, with respect to the ion channel-mediated mechanism, like L-amino acids, D-amino acid peptides will also form ion channel-like structures. Using atomic force microscopy (AFM), we imaged the structures of both D- and L-enantiomers of the full length Aβ(1-42) when reconstituted in lipid bilayers. AFM imaging shows that both L- and D-Aβ isomers form similar channel-like structures. Molecular dynamics (MD) simulations support the AFM imaged 3D structures. Previously, we have shown that D-Aβ(1-42) channels conduct ions similarly to their L- counterparts. Taken together, our results support the direct mechanism of Aβ ion channel-mediated destabilization of ionic homeostasis rather than the indirect mechanism through Aβ interaction with membrane receptors.
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Affiliation(s)
- Laura Connelly
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Materials Science Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Fernando Teran Arce
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Materials Science Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hyunbum Jang
- Center for Cancer Research Nanobiology Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD 21702, USA
| | - Ricardo Capone
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Materials Science Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Samuel A. Kotler
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Materials Science Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Srinivasan Ramachandran
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Materials Science Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Bruce L. Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience Human Behavior, University of California, Los Angeles, CA 90024, USA
| | - Ruth Nussinov
- Center for Cancer Research Nanobiology Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD 21702, USA
| | - Ratnesh Lal
- Departments of Bioengineering and of Mechanical and Aerospace Engineering and Materials Science Program, University of California, San Diego, La Jolla, CA 92093, USA
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93
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Harris F, Dennison SR, Phoenix DA. Aberrant action of amyloidogenic host defense peptides: a new paradigm to investigate neurodegenerative disorders? FASEB J 2012; 26:1776-81. [PMID: 22308196 DOI: 10.1096/fj.11-199208] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Host defense peptides (HDPs) are components of the innate immune system with activity against a broad range of microbes. In some cases, it appears that this activity is mediated by the ability of these peptides to permeabilize microbial membranes via the formation of amyloid associated structures. Recent evidence suggests that the naturally occurring function of the Aβ40 and Aβ42 peptides, which are causative agents of Alzheimer's disease, may be to serve as amyloidogenic HDPs. Here, it is hypothesized that the neurotoxicity of these peptides is related to aberrant use of their amyloid-mediated antimicrobial mechanisms, which provides the as yet unexplored paradigm of a relationship among HDPs, neurodegenerative disorders, and other conditions that could contribute to their understanding and remediation.
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94
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Blanco LP, Evans ML, Smith DR, Badtke MP, Chapman MR. Diversity, biogenesis and function of microbial amyloids. Trends Microbiol 2012; 20:66-73. [PMID: 22197327 PMCID: PMC3278576 DOI: 10.1016/j.tim.2011.11.005] [Citation(s) in RCA: 235] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 11/09/2011] [Accepted: 11/11/2011] [Indexed: 11/27/2022]
Abstract
Amyloid is a distinct β-sheet-rich fold that many proteins can acquire. Frequently associated with neurodegenerative diseases in humans, including Alzheimer's, Parkinson's and Huntington's diseases, amyloids are traditionally considered the product of protein misfolding. However, the amyloid fold is now recognized as a ubiquitous part of normal cellular biology. Functional amyloids have been identified in nearly all facets of cellular life, with microbial functional amyloids leading the way. Unlike disease-associated amyloids, functional amyloids are assembled by dedicated, directed pathways and ultimately perform a physiological function that benefits the organism. The evolved amyloid assembly and disassembly pathways of microbes have provided novel insights into how cells have harnessed the amyloid assembly process for productive means. An understanding of functional amyloid biogenesis promises to provide a fresh perspective on the molecular events that underlie disease-associated amyloidogenesis. Here, we review functional microbial amyloids with an emphasis on curli fibers and their role in promoting biofilm formation and other community behaviors.
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Affiliation(s)
- Luz P Blanco
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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95
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Vivcharuk V, Kaznessis YN. Thermodynamic analysis of protegrin-1 insertion and permeation through a lipid bilayer. J Phys Chem B 2011; 115:14704-12. [PMID: 22044268 PMCID: PMC3461958 DOI: 10.1021/jp205153y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics (MD) simulations are used to study the pathway for the insertion of the cationic antimicrobial peptide protegrin-1 (PG1) into mixed anionic lipid bilayers composed of palmitoyl-oleoyl-phosphatidylglycerol (POPG) and palmitoyl-oleoyl-phosphatidylethanolamine (POPE) in a 1:3 ratio (POPG/POPE). We calculate the potential of mean force (PMF) during the transfer of the peptide from the bulk aqueous phase to the transmembrane (TM) configuration using the adaptive biasing force (ABF) method. We find that the PMF has two energy minima separated by an energy barrier. One minimum corresponds to the fully transmembrane inserted state, with a free energy of -20.1 kcal/mol. The second PMF minimum, which corresponds to adsorption to the membrane surface, has a value of -2.5 kcal/mol. The PMF also shows the existence of a free energy barrier of +6.3 kcal/mol for the insertion process. Using the Kramers theory Langevin equation and the Grote-Hynes theory generalized Langevin equation, we calculated the transmission coefficient for PG1 diffusion through the potential barrier. We focus on the use of the PMF and the time correlation function of the fluctuation of the instantaneous force to calculate the rate constants for insertion/deinsertion of PG1 from the mixed POPG/POPE membrane. The influence of the activation free energy barrier on the dynamics of the insertion and permeation of peptides through the membrane are discussed.
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Affiliation(s)
- Victor Vivcharuk
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132, USA
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96
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Ramachandran S, Teran Arce F, Lal R. Potential role of atomic force microscopy in systems biology. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 3:702-16. [PMID: 21766465 DOI: 10.1002/wsbm.154] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Systems biology is a quantitative approach for understanding a biological system at its global level through systematic perturbation and integrated analysis of all its components. Simultaneous acquisition of information data sets pertaining to the system components (e.g., genome, proteome) is essential to implement this approach. There are limitations to such an approach in measuring gene expression levels and accounting for all proteins in the system. The success of genomic studies is critically dependent on polymerase chain reaction (PCR) for its amplification, but PCR is very uneven in amplifying the samples, ineffective in scarce samples and unreliable in low copy number transcripts. On the other hand, lack of amplifying techniques for proteins critically limits their identification to only a small fraction of high concentration proteins. Atomic force microscopy (AFM), AFM cantilever sensors, and AFM force spectroscopy in particular, could address these issues directly. In this article, we reviewed and assessed their potential role in systems biology.
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97
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Kagan BL. Antimicrobial amyloids? Biophys J 2011; 100:1597-8. [PMID: 21463571 DOI: 10.1016/j.bpj.2011.02.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 11/26/2022] Open
Affiliation(s)
- Bruce L Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California, Los Angeles, California, USA.
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