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Das D, Bharadwaz P, Mattaparthi VSK. Computational investigation on the effect of the peptidomimetic inhibitors (NPT100-18A and NPT200-11) on the α-synuclein and lipid membrane interactions. J Biomol Struct Dyn 2023:1-12. [PMID: 37768058 DOI: 10.1080/07391102.2023.2262599] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023]
Abstract
Parkinson's disease (PD) is associated with α-synuclein (α-Syn), a presynaptic protein that binds to cell membranes. The molecular pathophysiology of PD most likely begins with the binding of α-Syn to membranes. Recently, two peptidomimetic inhibitors (NPT100-18A and NPT200-11) were identified to potentially interact with α-Syn and affect the interaction of α-Syn with the membrane. In this study, the effect of the two peptidomimetic inhibitors on the α-Syn-membrane interaction was demonstrated. DFT calculations were performed for optimization of the two inhibitors, and the nucleophilicity (N) and electrophilicity (ω) of NPT100-18A and NPT200-11 were calculated to be 3.90 and 3.86 (N); 1.06 and 1.04 (ω), respectively. Using the docking tool (CB-dock2), the two α-Syn-peptidomimetic inhibitor complexes (α-Syn-NPT100-18A and α-Syn-NPT200-11) have been prepared. Then all-atom molecular dynamics (MD) simulation was carried out on the α-Syn (control), α-Syn-NPT100-18A and α-Syn-NPT200-11 complex systems in presence of DOPE: DOPS: DOPC (5:3:2) lipid bilayer. From the conformational dynamics analysis, the 3-D structure of α-Syn was found to be stable, and the helices present in the regions (1-37) and (45-95) of α-Syn were found to be retained in the presence of the two peptidomimetic inhibitors. The electron density profile analysis revealed the binding modes of NAC and C-terminal region of α-Syn (in the presence of NPT200-11 inhibitor) with lipid membrane are in the close vicinity from the lipid bilayer centre. Our findings in this study on α-Syn-membrane interactions may be useful for developing a new therapeutic approach for treating PD and other neurodegenerative disorders.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Dorothy Das
- Molecular Modelling and Simulation Laboratory, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Priyam Bharadwaz
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Venkata Satish Kumar Mattaparthi
- Molecular Modelling and Simulation Laboratory, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
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2
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Han S, Seo MH, Lim S, Yeo S. Decrease in ITGA7 Levels Is Associated with an Increase in α-Synuclein Levels in an MPTP-Induced Parkinson's Disease Mouse Model and SH-SY5Y Cells. Int J Mol Sci 2021; 22:ijms222312616. [PMID: 34884422 PMCID: PMC8657770 DOI: 10.3390/ijms222312616] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 12/19/2022] Open
Abstract
We investigated the potential association between integrin α7 (ITGA7) and alpha-synuclein (α-syn) in a methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson’s disease (PD) mouse model. Tyrosine hydroxylase (TH), ITGA7, and α-syn expression in the substantia nigra (SN) of the brain were observed to examine the pathological characteristics of PD. To determine the relationship between ITGA7 and PD, the expression of TH and α-syn was investigated after ITGA7 siRNA knockdown in SH-SY5Y cells. The ITGA7 microarray signal was decreased in the SN of the MPTP group, indicating reduced ITGA7 expression compared to that in the control. The expression patterns of ITGA7 in the control group and those of α-syn in the MPTP group were similar on immunohistochemical staining. Reduction in ITGA7 expression by ITGA7 siRNA administration induced a decrease in TH expression and an increase in α-syn expression in SH-SY5Y cells. The decreased expression of ITGA7 significantly decreased the expression of bcl2 and increased the bax/bcl2 ratio in SH-SY5Y cells. These results suggest that reduced ITGA7 expression may be related to increased α-syn expression and apoptosis of dopaminergic cells in an MPTP-induced PD mouse model. To the best of our knowledge, this is the first study to show an association between ITGA7 and PD.
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Affiliation(s)
- Sangeun Han
- Department of Meridian and Acupoint, College of Korean Medicine, Kyung Hee University, Seoul 02453, Korea;
| | - Min Hyung Seo
- Department of Meridian and Acupoint, College of Korean Medicine, Sang Ji University, Wonju 26339, Korea;
| | - Sabina Lim
- Department of Meridian and Acupoint, College of Korean Medicine, Kyung Hee University, Seoul 02453, Korea;
- Correspondence: (S.L.); (S.Y.); Tel.: +82-962-0324 (S.L.); +82-33-738-7506 (S.Y.)
| | - Sujung Yeo
- Department of Meridian and Acupoint, College of Korean Medicine, Sang Ji University, Wonju 26339, Korea;
- Research Institute of Korean Medicine, Sang Ji University, Wonju 26339, Korea
- Correspondence: (S.L.); (S.Y.); Tel.: +82-962-0324 (S.L.); +82-33-738-7506 (S.Y.)
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3
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Lautenbach V, Hosseinpour S, Peukert W. Isoelectric Point of Proteins at Hydrophobic Interfaces. Front Chem 2021; 9:712978. [PMID: 34395381 PMCID: PMC8360839 DOI: 10.3389/fchem.2021.712978] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/19/2021] [Indexed: 12/02/2022] Open
Abstract
Structural and colloidal stability of proteins at different surfaces and interfaces is of great importance in many fields including medical, pharmaceutical, or material science. Due to their flexibility, proteins tend to respond to their environmental conditions and can undergo structural and conformational changes. For instance, alterations in physiological factors such as temperature, ions concentration, or pH as well as the adsorption to an interface can initiate protein aggregation. Therefore, at different surfaces and interfaces the characterization of the structural and colloidal stability of proteins, which is mainly influenced by their electrostatic and hydrophobic interactions, is of fundamental importance. In this study, we utilized sum frequency generation (SFG) spectroscopy to assess the role of solution pH on the polarity and magnitude of the electric field within the hydration shell of selected model proteins adsorbed to a hydrophobic surface. We used polystyrene (PS) as a model hydrophobic surface and determined the isoelectric point (IEP) of four structurally different model proteins. Comparing the measured IEP of proteins at the PS/solution or air/solution interface with that determined in the bulk solution via zeta potential measurement, we found significant similarities between the IEP of surface adsorbed proteins and those in the bulk aqueous phase. The pH dependence behavior of proteins was correlated to their amino acid composition and degree of hydrophobicity.
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Affiliation(s)
- Vanessa Lautenbach
- Institute of Particle Technology (LFG), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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4
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Ma L, Gholam Azad M, Dharmasivam M, Richardson V, Quinn RJ, Feng Y, Pountney DL, Tonissen KF, Mellick GD, Yanatori I, Richardson DR. Parkinson's disease: Alterations in iron and redox biology as a key to unlock therapeutic strategies. Redox Biol 2021; 41:101896. [PMID: 33799121 PMCID: PMC8044696 DOI: 10.1016/j.redox.2021.101896] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 12/13/2022] Open
Abstract
A plethora of studies indicate that iron metabolism is dysregulated in Parkinson's disease (PD). The literature reveals well-documented alterations consistent with established dogma, but also intriguing paradoxical observations requiring mechanistic dissection. An important fact is the iron loading in dopaminergic neurons of the substantia nigra pars compacta (SNpc), which are the cells primarily affected in PD. Assessment of these changes reveal increased expression of proteins critical for iron uptake, namely transferrin receptor 1 and the divalent metal transporter 1 (DMT1), and decreased expression of the iron exporter, ferroportin-1 (FPN1). Consistent with this is the activation of iron regulator protein (IRP) RNA-binding activity, which is an important regulator of iron homeostasis, with its activation indicating cytosolic iron deficiency. In fact, IRPs bind to iron-responsive elements (IREs) in the 3ꞌ untranslated region (UTR) of certain mRNAs to stabilize their half-life, while binding to the 5ꞌ UTR prevents translation. Iron loading of dopaminergic neurons in PD may occur through these mechanisms, leading to increased neuronal iron and iron-mediated reactive oxygen species (ROS) generation. The "gold standard" histological marker of PD, Lewy bodies, are mainly composed of α-synuclein, the expression of which is markedly increased in PD. Of note, an atypical IRE exists in the α-synuclein 5ꞌ UTR that may explain its up-regulation by increased iron. This dysregulation could be impacted by the unique autonomous pacemaking of dopaminergic neurons of the SNpc that engages L-type Ca+2 channels, which imparts a bioenergetic energy deficit and mitochondrial redox stress. This dysfunction could then drive alterations in iron trafficking that attempt to rescue energy deficits such as the increased iron uptake to provide iron for key electron transport proteins. Considering the increased iron-loading in PD brains, therapies utilizing limited iron chelation have shown success. Greater therapeutic advancements should be possible once the exact molecular pathways of iron processing are dissected.
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Affiliation(s)
- L Ma
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - M Gholam Azad
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia; Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - M Dharmasivam
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia; Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - V Richardson
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia; Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - R J Quinn
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - Y Feng
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - D L Pountney
- School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - K F Tonissen
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - G D Mellick
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia
| | - I Yanatori
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - D R Richardson
- School of Environment and Science, Griffith University Nathan, Brisbane, Queensland, Australia; Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia; Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia; Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan.
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5
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Jakubec M, Bariås E, Furse S, Govasli ML, George V, Turcu D, Iashchishyn IA, Morozova-Roche LA, Halskau Ø. Cholesterol-containing lipid nanodiscs promote an α-synuclein binding mode that accelerates oligomerization. FEBS J 2021; 288:1887-1905. [PMID: 32892498 DOI: 10.1111/febs.15551] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 07/28/2020] [Accepted: 09/01/2020] [Indexed: 01/09/2023]
Abstract
Dysregulation of the biosynthesis of cholesterol and other lipids has been implicated in many neurological diseases, including Parkinson's disease. Misfolding of α-synuclein (α-Syn), the main actor in Parkinson's disease, is associated with changes in a lipid environment. However, the exact molecular mechanisms underlying cholesterol effect on α-Syn binding to lipids as well as α-Syn oligomerization and fibrillation remain elusive, as does the relative importance of cholesterol compared to other factors. We probed the interactions and fibrillation behaviour of α-Syn using styrene-maleic acid nanodiscs, containing zwitterionic and anionic lipid model systems with and without cholesterol. Surface plasmon resonance and thioflavin T fluorescence assays were employed to monitor α-Syn binding, as well as fibrillation in the absence and presence of membrane models. 1 H-15 N-correlated NMR was used to monitor the fold of α-Syn in response to nanodisc binding, determining individual residue apparent affinities for the nanodisc-contained bilayers. The addition of cholesterol inhibited α-Syn interaction with lipid bilayers and, however, significantly promoted α-Syn fibrillation, with a more than a 20-fold reduction of lag times before fibrillation onset. When α-Syn bilayer interactions were analysed at an individual residue level by solution-state NMR, we observed two different effects of cholesterol. In nanodiscs made of DOPC, the addition of cholesterol modulated the NAC part of α-Syn, leading to stronger interaction of this region with the lipid bilayer. In contrast, in the nanodiscs comprising DOPC, DOPE and DOPG, the NAC part was mostly unaffected by the presence of cholesterol, while the binding of the N and the C termini was both inhibited.
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Affiliation(s)
- Martin Jakubec
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Espen Bariås
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Samuel Furse
- Department of Molecular Biology, University of Bergen, Norway
| | - Morten L Govasli
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
- Division of Infection and Immunity, University College London, London, UK
| | - Vinnit George
- Department of Chemistry, University of Bergen, Norway
| | - Diana Turcu
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Igor A Iashchishyn
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | | | - Øyvind Halskau
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
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6
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Watson MD, Flynn JD, Lee JC. Raman spectral imaging of 13C 2H 15N-labeled α-synuclein amyloid fibrils in cells. Biophys Chem 2020; 269:106528. [PMID: 33418468 DOI: 10.1016/j.bpc.2020.106528] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/11/2022]
Abstract
Parkinson's disease is characterized by the intracellular accumulation of α-synuclein (α-syn) amyloid fibrils, which are insoluble, β-sheet-rich protein aggregates. Raman spectroscopy is a powerful technique that reports on intrinsic molecular vibrations such as the coupled vibrational modes of the polypeptide backbone, yielding secondary structural information. However, in order to apply this method in cells, spectroscopically unique frequencies are necessary to resolve proteins of interest from the cellular proteome. Here, we report the use of 13C2H15N-labeled α-syn to study the localization of preformed fibrils fed to cells. Isotopic labeling shifts the amide-I (13CO) band away from endogenous 12CO vibrations, permitting secondary structural analysis of internalized α-syn fibrils. Similarly, 13C2H stretches move to lower energies in the "cellular quiet" region, where there is negligible biological spectral interference. This combination of well-resolved, distinct vibrations allows Raman spectral imaging of α-syn fibrils across a cell, which provides conformational information with spatial context.
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Affiliation(s)
- Matthew D Watson
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Jessica D Flynn
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States of America.
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7
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D’Onofrio M, Munari F, Assfalg M. Alpha-Synuclein-Nanoparticle Interactions: Understanding, Controlling and Exploiting Conformational Plasticity. Molecules 2020; 25:E5625. [PMID: 33260436 PMCID: PMC7731430 DOI: 10.3390/molecules25235625] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/25/2020] [Accepted: 11/27/2020] [Indexed: 12/29/2022] Open
Abstract
Alpha-synuclein (αS) is an extensively studied protein due to its involvement in a group of neurodegenerative disorders, including Parkinson's disease, and its documented ability to undergo aberrant self-aggregation resulting in the formation of amyloid-like fibrils. In dilute solution, the protein is intrinsically disordered but can adopt multiple alternative conformations under given conditions, such as upon adsorption to nanoscale surfaces. The study of αS-nanoparticle interactions allows us to better understand the behavior of the protein and provides the basis for developing systems capable of mitigating the formation of toxic aggregates as well as for designing hybrid nanomaterials with novel functionalities for applications in various research areas. In this review, we summarize current progress on αS-nanoparticle interactions with an emphasis on the conformational plasticity of the biomolecule.
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Affiliation(s)
| | | | - Michael Assfalg
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (M.D.); (F.M.)
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8
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Gilmozzi V, Gentile G, Castelo Rueda MP, Hicks AA, Pramstaller PP, Zanon A, Lévesque M, Pichler I. Interaction of Alpha-Synuclein With Lipids: Mitochondrial Cardiolipin as a Critical Player in the Pathogenesis of Parkinson's Disease. Front Neurosci 2020; 14:578993. [PMID: 33122994 PMCID: PMC7573567 DOI: 10.3389/fnins.2020.578993] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/10/2020] [Indexed: 12/31/2022] Open
Abstract
Alpha-Synuclein (α-Syn) is a central protein in the pathogenesis of synucleinopathies, a group of neurodegenerative disorders including Parkinson’s disease (PD). Although its role in neurotransmission is well established, the precise role of this protein in disease pathogenesis is still not fully understood. It is, however, widely regarded to be associated with the misfolding and accumulation of toxic intracellular aggregates. In fact, α-Syn is the most abundant protein component of Lewy bodies and Lewy neurites, which are also characterized by a high lipid content. Lipids, the main constituents of cellular membranes, have been implicated in many aspects of PD-related processes. α-Syn interacts with membrane phospholipids and free fatty acids via its N-terminal domain, and altered lipid-protein complexes might enhance both its binding to synaptic and mitochondrial membranes and its oligomerization. Several studies have highlighted a specific interaction of α-Syn with the phospholipid cardiolipin (CL), a major constituent of mitochondrial membranes. By interacting with CL, α-Syn is able to disrupt mitochondrial membrane integrity, leading to mitochondrial dysfunction. Additionally, externalized CL is able to facilitate the refolding of toxic α-Syn species at the outer mitochondrial membrane. In this review, we discuss how α-Syn/lipid interactions, in particular the α-Syn/CL interaction at the mitochondrial membrane, may affect α-Syn aggregation and mitochondrial dysfunction and may thus represent an important mechanism in the pathogenesis of PD.
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Affiliation(s)
- Valentina Gilmozzi
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Giovanna Gentile
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | | | - Andrew A Hicks
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Peter P Pramstaller
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy.,Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Alessandra Zanon
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Martin Lévesque
- Department of Psychiatry and Neurosciences, Cervo Brain Research Centre, Université Laval, Quebec, QC, Canada
| | - Irene Pichler
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
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9
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Amyloidogenic Intrinsically Disordered Proteins: New Insights into Their Self-Assembly and Their Interaction with Membranes. Life (Basel) 2020; 10:life10080144. [PMID: 32784399 PMCID: PMC7459996 DOI: 10.3390/life10080144] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/02/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022] Open
Abstract
Aβ, IAPP, α-synuclein, and prion proteins belong to the amyloidogenic intrinsically disordered proteins’ family; indeed, they lack well defined secondary and tertiary structures. It is generally acknowledged that they are involved, respectively, in Alzheimer’s, Type II Diabetes Mellitus, Parkinson’s, and Creutzfeldt–Jakob’s diseases. The molecular mechanism of toxicity is under intense debate, as many hypotheses concerning the involvement of the amyloid and the toxic oligomers have been proposed. However, the main role is represented by the interplay of protein and the cell membrane. Thus, the understanding of the interaction mechanism at the molecular level is crucial to shed light on the dynamics driving this phenomenon. There are plenty of factors influencing the interaction as mentioned above, however, the overall view is made trickier by the apparent irreproducibility and inconsistency of the data reported in the literature. Here, we contextualized this topic in a historical, and even more importantly, in a future perspective. We introduce two novel insights: the chemical equilibrium, always established in the aqueous phase between the free and the membrane phospholipids, as mediators of protein-transport into the core of the bilayer, and the symmetry-breaking of oligomeric aggregates forming an alternating array of partially ordered and disordered monomers.
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10
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The Role of Xenobiotics and Trace Metals in Parkinson’s Disease. Mol Neurobiol 2019; 57:1405-1417. [DOI: 10.1007/s12035-019-01832-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/01/2019] [Indexed: 12/21/2022]
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11
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Cholak E, Bucciarelli S, Bugge K, Johansen NT, Vestergaard B, Arleth L, Kragelund BB, Langkilde AE. Distinct α-Synuclein:Lipid Co-Structure Complexes Affect Amyloid Nucleation through Fibril Mimetic Behavior. Biochemistry 2019; 58:5052-5065. [DOI: 10.1021/acs.biochem.9b00925] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ersoy Cholak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen N, Denmark
| | - Saskia Bucciarelli
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen N, Denmark
| | - Katrine Bugge
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, and REPIN, Department of Biology, Faculty of Science, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Nicolai Tidemand Johansen
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen N, Denmark
| | - Bente Vestergaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen N, Denmark
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen N, Denmark
| | - Birthe B. Kragelund
- Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, and REPIN, Department of Biology, Faculty of Science, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Annette E. Langkilde
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen N, Denmark
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12
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Ferree AW. Cathepsin Oxidation Alters Alpha-Synuclein Processing. Front Neurol 2019; 10:530. [PMID: 31191432 PMCID: PMC6540588 DOI: 10.3389/fneur.2019.00530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/03/2019] [Indexed: 11/20/2022] Open
Affiliation(s)
- Andrew W Ferree
- Neurology Department, Boston University Medical Center, Boston, MA, United States
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13
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Sahoo A, Matysiak S. Computational insights into lipid assisted peptide misfolding and aggregation in neurodegeneration. Phys Chem Chem Phys 2019; 21:22679-22694. [DOI: 10.1039/c9cp02765c] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An overview of recent advances in computational investigation of peptide–lipid interactions in neurodegeneration – Alzheimer's, Parkinson's and Huntington's disease.
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Affiliation(s)
- Abhilash Sahoo
- Biophysics Program
- Institute of Physical Science and Technology
- University of Maryland
- College Park
- USA
| | - Silvina Matysiak
- Biophysics Program
- Institute of Physical Science and Technology
- University of Maryland
- College Park
- USA
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14
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Maldonado Vidaurri E, Chavez-Montes A, Garza Tapia M, Castro-Rios R, Gonzalez-Horta A. Differential interaction of α-synuclein N-terminal segment with mitochondrial model membranes. Int J Biol Macromol 2018; 119:1286-1293. [DOI: 10.1016/j.ijbiomac.2018.08.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 01/27/2023]
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15
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O'Leary EI, Jiang Z, Strub MP, Lee JC. Effects of phosphatidylcholine membrane fluidity on the conformation and aggregation of N-terminally acetylated α-synuclein. J Biol Chem 2018; 293:11195-11205. [PMID: 29853639 DOI: 10.1074/jbc.ra118.002780] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/22/2018] [Indexed: 12/15/2022] Open
Abstract
Membrane association of α-synuclein (α-syn), a neuronal protein associated with Parkinson's disease (PD), is involved in α-syn function and pathology. Most previous studies on α-syn-membrane interactions have not used the physiologically relevant N-terminally acetylated (N-acetyl) α-syn form nor the most naturally abundant cellular lipid, i.e. phosphatidylcholine (PC). Here, we report on how PC membrane fluidity affects the conformation and aggregation propensity of N-acetyl α-syn. It is well established that upon membrane binding, α-syn adopts an α-helical structure. Using CD spectroscopy, we show that N-acetyl α-syn transitions from α-helical to disordered at the lipid melting temperature (Tm ). We found that this fluidity sensing is a robust characteristic, unaffected by acyl chain length (Tm = 34-55 °C) and preserved in its homologs β- and γ-syn. Interestingly, both N-acetyl α-syn membrane binding and amyloid formation trended with lipid order (1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) > 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/sphingomyelin/cholesterol (2:2:1) ≥ DOPC), with gel-phase vesicles shortening aggregation kinetics and promoting fibril formation compared to fluid membranes. Furthermore, we found that acetylation enhances binding to PC micelles and small unilamellar vesicles with high curvature (r ∼16-20 nm) and that DPPC binding is reduced in the presence of cholesterol. These results confirmed that the exposure of hydrocarbon chains (i.e. packing defects) is essential for binding to zwitterionic gel membranes. Collectively, our in vitro results suggest that N-acetyl α-syn localizes to highly curved, ordered membranes inside a cell. We propose that age-related changes in membrane fluidity can promote the formation of amyloid fibrils, insoluble materials associated with PD.
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Affiliation(s)
- Emma I O'Leary
- From the Laboratory of Protein Conformation and Dynamics and
| | - Zhiping Jiang
- From the Laboratory of Protein Conformation and Dynamics and
| | - Marie-Paule Strub
- the Biochemistry and Biophysics Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Jennifer C Lee
- From the Laboratory of Protein Conformation and Dynamics and
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16
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Jiang Z, Flynn JD, Teague WE, Gawrisch K, Lee JC. Stimulation of α-synuclein amyloid formation by phosphatidylglycerol micellar tubules. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1840-1847. [PMID: 29501608 DOI: 10.1016/j.bbamem.2018.02.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/23/2018] [Accepted: 02/25/2018] [Indexed: 10/25/2022]
Abstract
α-Synuclein (α-Syn) is a presynaptic protein that is accumulated in its amyloid form in the brains of Parkinson's patients. Although its biological function remains unclear, α-syn has been suggested to bind to synaptic vesicles and facilitate neurotransmitter release. Recently, studies have found that α-syn induces membrane tubulation, highlighting a potential mechanism for α-syn to stabilize highly curved membrane structures which could have both functional and dysfunctional consequences. To understand how membrane remodeling by α-syn affects amyloid formation, we have studied the α-syn aggregation process in the presence of phosphatidylglycerol (PG) micellar tubules, which were the first reported example of membrane tubulation by α-syn. Aggregation kinetics, β-sheet content, and macroscopic protein-lipid structures were observed by Thioflavin T fluorescence, circular dichroism spectroscopy and transmission electron microscopy, respectively. Collectively, the presence of PG micellar tubules formed at a stochiometric (L/P = 1) ratio was found to stimulate α-syn fibril formation. Moreover, transmission electron microscopy and solid-state nuclear magnetic resonance spectroscopy revealed the co-assembly of PG and α-syn into fibril structures. However, isolated micellar tubules do not form fibrils by themselves, suggesting an important role of free α-syn monomers during amyloid formation. In contrast, fibrils did not form in the presence of excess PG lipids (≥L/P = 50), where most of the α-syn molecules are in a membrane-bound α-helical form. Our results provide new mechanistic insights into how membrane tubules modulate α-syn amyloid formation and support a pivotal role of protein-lipid interaction in the dysfunction of α-syn.
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Affiliation(s)
- Zhiping Jiang
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jessica D Flynn
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Walter E Teague
- Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Klaus Gawrisch
- Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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17
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Alpha-synuclein: Pathology, mitochondrial dysfunction and neuroinflammation in Parkinson’s disease. Neurobiol Dis 2018; 109:249-257. [DOI: 10.1016/j.nbd.2017.04.004] [Citation(s) in RCA: 339] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/29/2017] [Accepted: 04/05/2017] [Indexed: 12/12/2022] Open
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18
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de la Fuente C, Burke DG, Eaton S, Heales SJ. Inhibition of neuronal mitochondrial complex I or lysosomal glucocerebrosidase is associated with increased dopamine and serotonin turnover. Neurochem Int 2017; 109:94-100. [DOI: 10.1016/j.neuint.2017.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 02/16/2017] [Accepted: 02/21/2017] [Indexed: 01/31/2023]
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19
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Varkey J, Langen R. Membrane remodeling by amyloidogenic and non-amyloidogenic proteins studied by EPR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:127-139. [PMID: 28579098 PMCID: PMC5461824 DOI: 10.1016/j.jmr.2017.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/18/2017] [Accepted: 02/18/2017] [Indexed: 06/07/2023]
Abstract
The advancement in site-directed spin labeling of proteins has enabled EPR studies to expand into newer research areas within the umbrella of protein-membrane interactions. Recently, membrane remodeling by amyloidogenic and non-amyloidogenic proteins has gained a substantial interest in relation to driving and controlling vital cellular processes such as endocytosis, exocytosis, shaping of organelles like endoplasmic reticulum, Golgi and mitochondria, intracellular vesicular trafficking, formation of filopedia and multivesicular bodies, mitochondrial fusion and fission, and synaptic vesicle fusion and recycling in neurotransmission. Misregulation in any of these processes due to an aberrant protein (mutation or misfolding) or alteration of lipid metabolism can be detrimental to the cell and cause disease. Dissection of the structural basis of membrane remodeling by proteins is thus quite necessary for an understanding of the underlying mechanisms, but it remains a formidable task due to the difficulties of various common biophysical tools in monitoring the dynamic process of membrane binding and bending by proteins. This is largely since membranes generally complicate protein structure analysis and this problem is amplified for structural analysis in the presence of different types of membrane curvatures. Recent EPR studies on membrane remodeling by proteins show that a significant structural information can be generated to delineate the role of different protein modules, domains and individual amino acids in the generation of membrane curvature. These studies also show how EPR can complement the data obtained by high resolution techniques such as X-ray and NMR. This perspective covers the application of EPR in recent studies for understanding membrane remodeling by amyloidogenic and non-amyloidogenic proteins that is useful for researchers interested in using or complimenting EPR to gain better understanding of membrane remodeling. We also discuss how a single protein can generate different type of membrane curvatures using specific conformations for specific membrane structures and how EPR is a versatile tool well-suited to analyze subtle alterations in structures under such modifying conditions which otherwise would have been difficult using other biophysical tools.
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Affiliation(s)
- Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
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20
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Enhanced Autophagy Contributes to Protective Effects of GM1 Ganglioside Against Aβ1-42-Induced Neurotoxicity and Cognitive Deficits. Neurochem Res 2017; 42:2417-2426. [PMID: 28497346 DOI: 10.1007/s11064-017-2266-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/18/2017] [Accepted: 04/10/2017] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder. The aggregation of Aβ peptides, Aβ1-42 in particular, is thought to be a fundamental pathogenic mechanism leading to the neuronal damage in AD. Recently, monosialoganglioside GM1 is reported to possess pivotal neuroprotection in neurodegenerative diseases. Previous studies have focused on the conformational dynamics and the biochemical interaction of the amyloid-peptide with the GM1 ganglioside, as well as the protective effect of GM1 on cognition. However, the phenomenon of autophagy with regard to neuronal dysfunction in AD is less investigated. In the present study, GM1 treatment were investigated in an AD mouse model and cultured PC12 dells to examine cognition-protective and neuroprotective effects of GM1. Furthermore, GM1 was found to induce autophagy via testing light chain 3 (LC3), Beclin1, neighbor of BRCA1 gene 1 protein and p62 (a substrate of LC3). Chloroquine, an inhibitor of lysosomal, was used to exclude the interference of lysosome, which could fuse with autophagosome and then clear it. In the presence of the inhibitor of autophagy (3-methyladenine; 3-MA), the protective effect of GM1 on PC12 cells in Aβ (1-42) induced toxic conditions was diminished. Interestingly, the expression of histone deacetylase 1 was increased in PC12 cells when treated with GM1, indicating that autophagy might be activated by GM1 through a pathway integrates protein acetylation. This study provides a novel insight into the protective role of GM1 against Aβ (1-42)-induced neurotoxicity via enhancing autophagy.
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21
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Lucato CM, Lupton CJ, Halls ML, Ellisdon AM. Amyloidogenicity at a Distance: How Distal Protein Regions Modulate Aggregation in Disease. J Mol Biol 2017; 429:1289-1304. [PMID: 28342736 DOI: 10.1016/j.jmb.2017.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/12/2017] [Accepted: 03/14/2017] [Indexed: 12/14/2022]
Abstract
The misfolding of proteins to form amyloid is a key pathological feature of several progressive, and currently incurable, diseases. A mechanistic understanding of the pathway from soluble, native protein to insoluble amyloid is crucial for therapeutic design, and recent efforts have helped to elucidate the key molecular events that trigger protein misfolding. Generally, either global or local structural perturbations occur early in amyloidogenesis to expose aggregation-prone regions of the protein that can then self-associate to form toxic oligomers. Surprisingly, these initiating structural changes are often caused or influenced by protein regions distal to the classically amyloidogenic sequences. Understanding the importance of these distal regions in the pathogenic process has highlighted many remaining knowledge gaps regarding the precise molecular events that occur in classic aggregation pathways. In this review, we discuss how these distal regions can influence aggregation in disease and the recent technical and conceptual advances that have allowed this insight.
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Affiliation(s)
- Christina M Lucato
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Christopher J Lupton
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Andrew M Ellisdon
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.
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22
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Robotta M, Cattani J, Martins JC, Subramaniam V, Drescher M. Alpha-Synuclein Disease Mutations Are Structurally Defective and Locally Affect Membrane Binding. J Am Chem Soc 2017; 139:4254-4257. [PMID: 28298083 DOI: 10.1021/jacs.6b05335] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The intrinsically disordered human protein alpha-Synuclein (αS) has a prominent role in Parkinson's disease (PD) pathology. Several familial variants of αS are correlated with inherited PD. Disease mutations have been shown to have an impact on lipid membrane binding. Here, using electron paramagnetic resonance spectroscopy in combination with site-directed spin labeling, we show that familial PD-associated variants are structurally defective in membrane binding and alter the local binding properties of the protein.
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Affiliation(s)
- Marta Robotta
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Julia Cattani
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Juliana Cristina Martins
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany.,Department of Physics, State University of Londrina , 86057-970 Londrina, Brazil
| | - Vinod Subramaniam
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany.,Vrije Universiteit Amsterdam , De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | - Malte Drescher
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
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23
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Baumann A, Jorge-Finnigan A, Jung-Kc K, Sauter A, Horvath I, Morozova-Roche LA, Martinez A. Tyrosine Hydroxylase Binding to Phospholipid Membranes Prompts Its Amyloid Aggregation and Compromises Bilayer Integrity. Sci Rep 2016; 6:39488. [PMID: 28004763 PMCID: PMC5177901 DOI: 10.1038/srep39488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 11/21/2016] [Indexed: 12/14/2022] Open
Abstract
Tyrosine hydroxylase (TH), a rate-limiting enzyme in the synthesis of catecholamine neurotransmitters and hormones, binds to negatively charged phospholipid membranes. Binding to both large and giant unilamellar vesicles causes membrane permeabilization, as observed by efflux and influx of fluorescence dyes. Whereas the initial protein-membrane interaction involves the N-terminal tail that constitutes an extension of the regulatory ACT-domain, prolonged membrane binding induces misfolding and self-oligomerization of TH over time as shown by circular dichroism and Thioflavin T fluorescence. The gradual amyloid-like aggregation likely occurs through cross-β interactions involving aggregation-prone motives in the catalytic domains, consistent with the formation of chain and ring-like protofilaments observed by atomic force microscopy in monolayer-bound TH. PC12 cells treated with the neurotoxin 6-hydroxydopamine displayed increased TH levels in the mitochondrial fraction, while incubation of isolated mitochondria with TH led to a decrease in the mitochondrial membrane potential. Furthermore, cell-substrate impedance and viability assays showed that supplementing the culture media with TH compromises cell viability over time. Our results revealed that the disruptive effect of TH on cell membranes may be a cytotoxic and pathogenic factor if the regulation and intracellular stability of TH is compromised.
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Affiliation(s)
- Anne Baumann
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, 5021 Bergen, Norway
| | - Ana Jorge-Finnigan
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
| | - Kunwar Jung-Kc
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
| | - Alexander Sauter
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,Department of Clinical Dentistry, University of Bergen, 5009 Bergen, Norway
| | - Istvan Horvath
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | | | - Aurora Martinez
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
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24
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Wrasidlo W, Tsigelny IF, Price DL, Dutta G, Rockenstein E, Schwarz TC, Ledolter K, Bonhaus D, Paulino A, Eleuteri S, Skjevik ÅA, Kouznetsova VL, Spencer B, Desplats P, Gonzalez-Ruelas T, Trejo-Morales M, Overk CR, Winter S, Zhu C, Chesselet MF, Meier D, Moessler H, Konrat R, Masliah E. A de novo compound targeting α-synuclein improves deficits in models of Parkinson's disease. Brain 2016; 139:3217-3236. [PMID: 27679481 DOI: 10.1093/brain/aww238] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 06/21/2016] [Accepted: 08/01/2016] [Indexed: 12/24/2022] Open
Abstract
Abnormal accumulation and propagation of the neuronal protein α-synuclein has been hypothesized to underlie the pathogenesis of Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Here we report a de novo-developed compound (NPT100-18A) that reduces α-synuclein toxicity through a novel mechanism that involves displacing α-synuclein from the membrane. This compound interacts with a domain in the C-terminus of α-synuclein. The E83R mutation reduces the compound interaction with the 80-90 amino acid region of α-synuclein and prevents the effects of NPT100-18A. In vitro studies showed that NPT100-18A reduced the formation of wild-type α-synuclein oligomers in membranes, reduced the neuronal accumulation of α-synuclein, and decreased markers of cell toxicity. In vivo studies were conducted in three different α-synuclein transgenic rodent models. Treatment with NPT100-18A ameliorated motor deficits in mThy1 wild-type α-synuclein transgenic mice in a dose-dependent manner at two independent institutions. Neuropathological examination showed that NPT100-18A decreased the accumulation of proteinase K-resistant α-synuclein aggregates in the CNS and was accompanied by the normalization of neuronal and inflammatory markers. These results were confirmed in a mutant line of α-synuclein transgenic mice that is prone to generate oligomers. In vivo imaging studies of α-synuclein-GFP transgenic mice using two-photon microscopy showed that NPT100-18A reduced the cortical synaptic accumulation of α-synuclein within 1 h post-administration. Taken together, these studies support the notion that altering the interaction of α-synuclein with the membrane might be a feasible therapeutic approach for developing new disease-modifying treatments of Parkinson's disease and other synucleinopathies.
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Affiliation(s)
- Wolfgang Wrasidlo
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Igor F Tsigelny
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA.,2 San Diego Supercomputer Center, University of California San Diego, La Jolla, CA 92093, USA
| | - Diana L Price
- 3 Neuropore Therapies, Inc., San Diego, CA 92121, USA
| | - Garima Dutta
- 4 Department of Neurology, University of California, Los Angeles, CA, 90095-1769, USA
| | - Edward Rockenstein
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | | | | | | | - Amy Paulino
- 3 Neuropore Therapies, Inc., San Diego, CA 92121, USA
| | - Simona Eleuteri
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Åge A Skjevik
- 2 San Diego Supercomputer Center, University of California San Diego, La Jolla, CA 92093, USA.,6 Department of Biomedicine, University of Bergen, N-5009 Bergen, Norway
| | | | - Brian Spencer
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paula Desplats
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tania Gonzalez-Ruelas
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Cassia R Overk
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Chunni Zhu
- 4 Department of Neurology, University of California, Los Angeles, CA, 90095-1769, USA
| | | | - Dieter Meier
- 3 Neuropore Therapies, Inc., San Diego, CA 92121, USA
| | | | | | - Eliezer Masliah
- 1 Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA .,9 Department of Pathology, University of California, San Diego, La Jolla, CA 92093, USA
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25
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Lee JH, Ying J, Bax A. Nuclear Magnetic Resonance Observation of α-Synuclein Membrane Interaction by Monitoring the Acetylation Reactivity of Its Lysine Side Chains. Biochemistry 2016; 55:4949-59. [PMID: 27455358 PMCID: PMC5015657 DOI: 10.1021/acs.biochem.6b00637] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
interaction between α-synuclein (αS) protein and
lipid membranes is key to its role in synaptic vesicle homeostasis
and plays a role in initiating fibril formation, which is implicated
in Parkinson’s disease. The natural state of αS inside
the cell is generally believed to be intrinsically disordered, but
chemical cross-linking experiments provided evidence of a tetrameric
arrangement, which was reported to be rich in α-helical secondary
structure based on circular dichroism (CD). Cross-linking relies on
chemical modification of the protein’s Lys Cε amino groups, commonly by glutaraldehyde, or by disuccinimidyl glutarate
(DSG), with the latter agent preferred for cellular assays. We used
ultra-high-resolution homonuclear decoupled nuclear magnetic resonance
experiments to probe the reactivity of the 15 αS Lys residues
toward N-succinimidyl acetate, effectively half the
DSG cross-linker, which results in acetylation of Lys. The intensities
of both side chain and backbone amide signals of acetylated Lys residues
provide direct information about the reactivity, showing a difference
of a factor of 2.5 between the most reactive (K6) and the least reactive
(K102) residue. The presence of phospholipid vesicles decreases reactivity
of most Lys residues by up to an order of magnitude at high lipid:protein
stoichiometries (500:1), but only weakly at low ratios. The decrease
in Lys reactivity is found to be impacted by lipid composition, even
for vesicles that yield similar αS CD signatures. Our data provide
new insight into the αS–bilayer interaction, including
the pivotal state in which the available lipid surface is limited.
Protection of Lys Cε amino groups by αS–bilayer
interaction will strongly impact quantitative interpretation of DSG
cross-linking experiments.
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Affiliation(s)
- Jung Ho Lee
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
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26
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Alpha-synuclein and familial variants affect the chain order and the thermotropic phase behavior of anionic lipid vesicles. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1206-1214. [PMID: 27177693 DOI: 10.1016/j.bbapap.2016.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/15/2016] [Accepted: 05/07/2016] [Indexed: 12/15/2022]
Abstract
Alpha-synuclein (aSN) is a presynaptic protein with a pathological role in Parkinson's disease (PD). The mutants A30P, E46K and A53T are involved in PD early-onset forms. aSN is natively unfolded but can self-assemble to oligomers and fibrils and binds anionic membranes in a helical conformation. We study the influence of wild-type (wt) aSN and familial variants on the chain order and thermotropic phase behavior of anionic dimyristoylphosphatidylglycerol (DMPG) bilayers by using electron spin resonance and calorimetry, respectively. The alpha-helical conformation of the proteins in the membrane-bound state is assessed by circular dichroism thermal scans. wt and mutated aSN upon binding to fluid DMPG vesicles progressively increase chain order. Lipid:protein molar binding stoichiometries correspond to 50 for A30P, 35-36 for aSN and A53T, 30 for E46K. The temperature range over which the variants assume the α-helical fold correlates directly with the density of proteins on vesicle surfaces. All variants preserve the characteristic chain flexibility gradient and impart motional restriction in the lipid chain. This is evident at the first CH2 segments and is markedly reduced at the chain termini, disappearing completely for A30P. The proteins slightly reduce DMPG main transition temperature, revealing preferential affinity for the fluid phase, and broaden the transition, promoting gel-fluid phase coexistence. The overall results are consistent with protein surface association in which the degree of binding correlates with the degree of folding and perturbation of the membrane bilayer. However, the degree of binding of monomer to membrane does not correlate directly with aSN toxicity in vivo.
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27
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In Vitro Studies of Membrane Permeability Induced by Amyloidogenic Polypeptides Using Large Unilamellar Vesicles. Methods Mol Biol 2016; 1345:283-90. [PMID: 26453219 PMCID: PMC5627766 DOI: 10.1007/978-1-4939-2978-8_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The process of amyloid formation is cytotoxic and contributes to a wide range of human diseases, but the mechanisms of amyloid-induced cytotoxicity are not well understood. It has been proposed that amyloidogenic peptides exert their toxic effects by damaging membranes. Membrane disruption is clearly not the only mechanism of toxicity, but the literature suggests that loss of membrane integrity may be a contributing factor. In this chapter we describe the measurement of in vitro membrane leakage induced by amyloidogenic proteins via the use of model vesicles. We use islet amyloid polypeptide (IAPP, amylin) as an example, but the methods are general.
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28
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Ghio S, Kamp F, Cauchi R, Giese A, Vassallo N. Interaction of α-synuclein with biomembranes in Parkinson's disease--role of cardiolipin. Prog Lipid Res 2015; 61:73-82. [PMID: 26703192 DOI: 10.1016/j.plipres.2015.10.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/14/2015] [Accepted: 10/30/2015] [Indexed: 12/15/2022]
Abstract
One of the key molecular events underlying the pathogenesis of Parkinson's disease (PD) is the aberrant misfolding and aggregation of the α-synuclein (αS) protein into higher-order oligomers that play a key role in neuronal dysfunction and degeneration. A wealth of experimental data supports the hypothesis that the neurotoxicity of αS oligomers is intrinsically linked with their ability to interact with, and disrupt, biological membranes; especially those membranes having negatively-charged surfaces and/or lipid packing defects. Consequences of αS-lipid interaction include increased membrane tension, permeation by pore formation, membrane lysis and/or leakage due to the extraction of lipids from the bilayer. Moreover, we assert that the interaction of αS with a liquid-disordering phospholipid uniquely enriched in mitochondrial membranes, namely cardiolipin (1,3-diphosphatidyl-sn-glycerol, CL), helps target the αS oligomeric complexes intracellularly to mitochondria. Binding mediated by CL may thus represent an important pathomechanism by which cytosolic αS could physically associate with mitochondrial membranes and disrupt their integrity. Impaired mitochondrial function culminates in a cellular bioenergetic crisis and apoptotic death. To conclude, we advocate the accelerated discovery of new drugs targeting this pathway in order to restore mitochondrial function in PD.
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Affiliation(s)
- Stephanie Ghio
- Dept. of Physiology and Biochemistry, University of Malta, Msida, Malta
| | - Frits Kamp
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University & DZNE, 81377 Munich, Germany
| | - Ruben Cauchi
- Dept. of Physiology and Biochemistry, University of Malta, Msida, Malta
| | - Armin Giese
- Zentrum für Neuropathologie und Prionforschung, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Neville Vassallo
- Dept. of Physiology and Biochemistry, University of Malta, Msida, Malta.
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α-Synuclein interactions with phospholipid model membranes: Key roles for electrostatic interactions and lipid-bilayer structure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2002-12. [DOI: 10.1016/j.bbamem.2015.06.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 12/31/2022]
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Anunciado D, Rai DK, Qian S, Urban V, O'Neill H. Small-angle neutron scattering reveals the assembly of alpha-synuclein in lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1881-1889. [PMID: 26321599 DOI: 10.1016/j.bbapap.2015.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/12/2015] [Accepted: 08/25/2015] [Indexed: 12/15/2022]
Abstract
The aggregation of α-synuclein (asyn), an intrinsically disordered protein (IDP), is a hallmark in Parkinson's disease (PD). We investigated the conformational changes that asyn undergoes in the presence of membrane and membrane mimetics using small-angle neutron scattering (SANS). In solution, asyn is monomeric and unfolded assuming an ensemble of conformers spanning extended and compact conformations. Using the contrast variation technique and SANS, the protein scattering signal in the membrane-protein complexes is selectively highlighted in order to monitor its conformational changes in this environment. We showed that in the presence of phospholipid membranes asyn transitions from a monodisperse state to aggregated structures with sizes ranging from 200 to 900Å coexisting with the monomeric species. Detailed SANS data analysis revealed that asyn aggregates have a hierarchical organization in which clusters of smaller asyn aggregates assemble to form the larger structures. This study provides new insight into the mechanism of asyn aggregation. We propose an aggregation mechanism in which stable asyn aggregates seed the aggregation process and hence the hierarchical assembly of structures. Our findings demonstrate that membrane-induced conformational changes in asyn lead to its heterogeneous aggregation which could be physiologically relevant in its function or in the diseased state.
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Affiliation(s)
- Divina Anunciado
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Durgesh K Rai
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Shuo Qian
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Volker Urban
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Hugh O'Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
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Garten M, Prévost C, Cadart C, Gautier R, Bousset L, Melki R, Bassereau P, Vanni S. Methyl-branched lipids promote the membrane adsorption of α-synuclein by enhancing shallow lipid-packing defects. Phys Chem Chem Phys 2015; 17:15589-97. [DOI: 10.1039/c5cp00244c] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reconstitution experiments on Giant Unilamellar Vesicles and Molecular Dynamics Simulations indicate that alpha-synuclein binds to neutral flat membranes in the presence of methyl-branched lipids.
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Affiliation(s)
| | | | | | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire
- Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique
- UMR 7275
- 06560 Valbonne
- France
| | - Luc Bousset
- CNRS
- Paris Saclay Institute of Neuroscience
- Gif-sur-Yvette
- France
| | - Ronald Melki
- CNRS
- Paris Saclay Institute of Neuroscience
- Gif-sur-Yvette
- France
| | | | - Stefano Vanni
- Institut de Pharmacologie Moléculaire et Cellulaire
- Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique
- UMR 7275
- 06560 Valbonne
- France
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Giráldez-Pérez RM, Antolín-Vallespín M, Muñoz MD, Sánchez-Capelo A. Models of α-synuclein aggregation in Parkinson's disease. Acta Neuropathol Commun 2014; 2:176. [PMID: 25497491 PMCID: PMC4272812 DOI: 10.1186/s40478-014-0176-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 12/04/2014] [Indexed: 12/13/2022] Open
Abstract
Parkinson's disease (PD) is not only characterized by motor disturbances but also, by cognitive, sensory, psychiatric and autonomic dysfunction. It has been proposed that some of these symptoms might be related to the widespread pathology of α-synuclein (α-syn) aggregation in different nuclei of the central and peripheral nervous system. However, the pathogenic formation of α-syn aggregates in different brain areas of PD patients is poorly understood. Most experimental models of PD are valuable to assess specific aspects of its pathogenesis, such as toxin-induced dopaminergic neurodegeneration. However, new models are required that reflect the widespread and progressive formation of α-syn aggregates in different brain areas. Such α-syn aggregation is induced in only a few animal models, for example perikaryon inclusions are found in rats administered rotenone, aggregates with a neuritic morphology develop in mice overexpressing either mutated or wild-type α-syn, and in Smad3 deficient mice, aggregates form extensively in the perikaryon and neurites of specific brain nuclei. In this review we focus on α-syn aggregation in the human disorder, its genetics and the availability of experimental models. Indeed, evidences show that dopamine (DA) metabolism may be related to α-syn and its conformational plasticity, suggesting an interesting link between the two pathological hallmarks of PD: dopaminergic neurodegeneration and Lewy body (LB) formation.
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Affiliation(s)
- Rosa María Giráldez-Pérez
- />CIBERNED - Ser. Neurobiología – Investigación, Hospital Universitario Ramón y Cajal – IRYCIS, Ctra. Colmenar Viejo Km 9, 28034 Madrid, Spain
- />Departamento Fisiología, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain
| | - Mónica Antolín-Vallespín
- />CIBERNED - Ser. Neurobiología – Investigación, Hospital Universitario Ramón y Cajal – IRYCIS, Ctra. Colmenar Viejo Km 9, 28034 Madrid, Spain
| | - María Dolores Muñoz
- />Unidad de Neurología Experimental, Hospital Universitario Ramón y Cajal – IRYCIS, Ctra. Colmenar Viejo Km 9, 28034 Madrid, Spain
| | - Amelia Sánchez-Capelo
- />CIBERNED - Ser. Neurobiología – Investigación, Hospital Universitario Ramón y Cajal – IRYCIS, Ctra. Colmenar Viejo Km 9, 28034 Madrid, Spain
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Mattam U, Jagota A. Daily rhythms of serotonin metabolism and the expression of clock genes in suprachiasmatic nucleus of rotenone-induced Parkinson's disease male Wistar rat model and effect of melatonin administration. Biogerontology 2014; 16:109-23. [PMID: 25430725 DOI: 10.1007/s10522-014-9541-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/07/2014] [Indexed: 12/21/2022]
Abstract
The circadian system in suprachiasmatic nucleus (SCN) involves regulated serotonin levels and coordinated expression of various clock genes. To understand circadian disfunction in the age-related neurodegenerative disorder Parkinson's disease (PD), the rotenone-induced PD (RIPD) male Wistar rat model was used. The alterations in the rhythmic dynamic equilibrium of interactions between the various components of serotonin metabolism and the molecular clock were measured. There was significant decrease in the mean 24 h levels of tryptophan, 5-hydroxytryptophan (5-HTP), serotonin (5-HT), N-acetyl serotonin (NAS) and melatonin (MEL) by approximately 63, 51, 76 and 96% respectively ( p ≤ 0.05). However significant increase in 5-methoxy indole acetic acid (5-MIAA), 5-methoxy tryptophol (5-MTOH), 5-hydroxy tryptophol (5-HTOH) indicated increased serotonin catabolism with the abolition of daily rhythms of MEL, 5-HTP and 5-MIAA in RIPD. 24 h mean levels of rPer1, rCry1, rBmal1 reduced by about 0.5, 0.74 and 0.39-fold and increased for rPer2 by about 1.7-fold. The daily pulse of rPer2, rCry1, rCry2 and rBmal1 significantly decreased by 0.36, 0.6, 0.14, 0.1 and 0.2-fold. As melatonin, an antioxidant and an endogenous synchronizer of rhythm declined in RIPD male Wistar rat model, the effects of melatonin-administration on the rhythmic expression of various clock genes were studied. Interestingly, melatonin-administration resulted in restoration of the phase of rPer1 daily rhythm in RIPD indicating differential sensitivity of various clock components towards melatonin. The animals which were administered both rotenone and MEL for 48 days interestingly showed neuroprotective effects in dark phase on correlations between expression of various genes.
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Affiliation(s)
- Ushodaya Mattam
- Neurobiology and Molecular Chronobiology Laboratory, Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
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Robotta M, Gerding HR, Vogel A, Hauser K, Schildknecht S, Karreman C, Leist M, Subramaniam V, Drescher M. Alpha-synuclein binds to the inner membrane of mitochondria in an α-helical conformation. Chembiochem 2014; 15:2499-502. [PMID: 25209675 DOI: 10.1002/cbic.201402281] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Indexed: 12/15/2022]
Abstract
The human alpha-Synuclein (αS) protein is of significant interest because of its association with Parkinson's disease and related neurodegenerative disorders. The intrinsically disordered protein (140 amino acids) is characterized by the absence of a well-defined structure in solution. It displays remarkable conformational flexibility upon macromolecular interactions, and can associate with mitochondrial membranes. Site-directed spin-labeling in combination with electron paramagnetic resonance spectroscopy enabled us to study the local binding properties of αS on artificial membranes (mimicking the inner and outer mitochondrial membranes), and to evaluate the importance of cardiolipin in this interaction. With pulsed, two-frequency, double-electron electron paramagnetic resonance (DEER) approaches, we examined, to the best of our knowledge for the first time, the conformation of αS bound to isolated mitochondria.
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Affiliation(s)
- Marta Robotta
- Department of Chemistry and Biology, Konstanz Research School Chemical Biology (KoRS-CB) and the Zukunftskolleg, University of Konstanz, 78457 Konstanz (Germany)
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35
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Kasai T, Tokuda T, Ishii R, Ishigami N, Tsuboi Y, Nakagawa M, Mizuno T, El-Agnaf OMA. Increased α-synuclein levels in the cerebrospinal fluid of patients with Creutzfeldt-Jakob disease. J Neurol 2014; 261:1203-9. [PMID: 24737170 DOI: 10.1007/s00415-014-7334-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 12/01/2022]
Abstract
Recent studies have shown that cerebrospinal fluid (CSF) levels of α-synuclein (α-syn) are highly elevated in patients with Creutzfeldt-Jakob disease (CJD) compared to controls. However, the diagnostic value of CSF α-syn in CJD has not been established. To confirm whether CSF α-syn is increased in CJD and is a useful marker for this disease, two independent enzyme-linked immunoabsorbent assays (ELISAs) specific for α-syn were used: ELISA 211-FL140, which is specific for full-length α-syn, and ELISA N19-FL140, which is specific for the full-length and associated C-terminal truncated forms of α-syn. CSF samples from 24 patients with CJD and 24 controls were assessed in this study. We found that samples from the CJD patients showed significantly higher levels of CSF α-syn compared to controls in both ELISA (211-FL140 or N19-FL140) tests (P = 0.0467 and P = 0.0010, respectively). However, there was a considerable overlap in the concentration ranges of the two groups of subjects. We also measured the levels of total tau (t-tau) protein in these samples and found that CSF t-tau levels were 5-10-times higher in the CJD group (P < 0.0001) compared with the controls. When the CSF t-tau and α-syn levels were combined, the area under the ROC curve (AUC) was slightly increased in clinically diagnosed CJD cases (AUC of 0.964) relative to an AUC of 0.943 for increased CSF t-tau alone. The combined use of CSF α-syn and t-tau levels may be a useful biomarker for the diagnosis of CJD.
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Affiliation(s)
- Takashi Kasai
- Department of Neurology, Research Institute for Geriatrics, Kyoto Prefectural University of Medicine, Kyoto, 602-0841, Japan,
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36
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Ca(2+) modulating α-synuclein membrane transient interactions revealed by solution NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:853-8. [PMID: 24316000 DOI: 10.1016/j.bbamem.2013.11.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/07/2013] [Accepted: 11/25/2013] [Indexed: 01/08/2023]
Abstract
α-Synuclein is involved in Parkinson's disease and its interaction with cell membrane is crucial to its pathological and physiological functions. Membrane properties, such as curvature and lipid composition, have been shown to affect the interactions by various techniques, but ion effects on α-synuclein membrane interactions remain elusive. Ca(2+) dynamic fluctuation in neurons plays important roles in the onset of Parkinson's disease and its influx is considered as one of the reasons to cause cell death. Using solution Nuclear Magnetic Resonance (NMR) spectroscopy, here we show that Ca(2+) can modulate α-synuclein membrane interactions through competitive binding to anionic lipids, resulting in dissociation of α-synuclein from membranes. These results suggest a negative modulatory effect of Ca(2+) on membrane mediated normal function of α-synuclein, which may provide a clue, to their dysfunction in neurodegenerative disease.
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37
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Jiang Z, de Messieres M, Lee JC. Membrane remodeling by α-synuclein and effects on amyloid formation. J Am Chem Soc 2013; 135:15970-3. [PMID: 24099487 PMCID: PMC3859146 DOI: 10.1021/ja405993r] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
α-Synuclein (α-Syn), an intrinsically disordered protein, is associated with Parkinson's disease. Though molecular pathogenic mechanisms are ill-defined, mounting evidence connects its amyloid forming and membrane binding propensities to disease etiology. Contrary to recent data suggesting that membrane remodeling by α-syn involves anionic phospholipids and helical structure, we discovered that the protein deforms vesicles with no net surface charge (phosphatidylcholine, PC) into tubules (average diameter ∼20 nm). No discernible secondary structural changes were detected by circular dichroism spectroscopy upon the addition of vesicles. Notably, membrane remodeling inhibits α-syn amyloid formation affecting both lag and growth phases. Using five single tryptophan variants and time-resolved fluorescence anisotropy measurements, we determined that α-syn influences bilayer structure with surprisingly weak interaction and no site specificity (partition constant, Kp ∼ 300 M(-1)). Vesicle deformation by α-syn under a variety of different lipid/protein conditions is characterized via transmission electron microscopy. As cellular membranes are enriched in PC lipids, these results support possible biological consequences for α-syn induced membrane remodeling related to both function and pathogenesis.
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Affiliation(s)
- Zhiping Jiang
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Michel de Messieres
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jennifer C. Lee
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
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38
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Does Restraining Nitric Oxide Biosynthesis Rescue from Toxins-Induced Parkinsonism and Sporadic Parkinson's Disease? Mol Neurobiol 2013; 49:262-75. [DOI: 10.1007/s12035-013-8517-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 07/16/2013] [Indexed: 12/21/2022]
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Deleersnijder A, Gerard M, Debyser Z, Baekelandt V. The remarkable conformational plasticity of alpha-synuclein: blessing or curse? Trends Mol Med 2013; 19:368-77. [DOI: 10.1016/j.molmed.2013.04.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 04/03/2013] [Accepted: 04/03/2013] [Indexed: 12/21/2022]
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Varkey J, Mizuno N, Hegde BG, Cheng N, Steven AC, Langen R. α-Synuclein oligomers with broken helical conformation form lipoprotein nanoparticles. J Biol Chem 2013; 288:17620-30. [PMID: 23609437 DOI: 10.1074/jbc.m113.476697] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
α-Synuclein (αS) is a membrane-binding protein with sequence similarity to apolipoproteins and other lipid-carrying proteins, which are capable of forming lipid-containing nanoparticles, sometimes referred to as "discs." Previously, it has been unclear whether αS also possesses this property. Using cryo-electron microscopy and light scattering, we found that αS can remodel phosphatidylglycerol vesicles into nanoparticles whose shape (ellipsoidal) and dimensions (in the 7-10-nm range) resemble those formed by apolipoproteins. The molar ratio of αS to lipid in nanoparticles is ∼1:20, and αS is oligomeric (including trimers and tetramers). Similar nanoparticles form when αS is added to vesicles of mitochondrial lipids. This observation suggests a mechanism for the previously reported disruption of mitochondrial membranes by αS. Circular dichroism and four-pulse double electron electron resonance experiments revealed that in nanoparticles αS assumes a broken helical conformation distinct from the extended helical conformation adopted when αS is bound to intact vesicles or membrane tubules. We also observed αS-dependent tubule and nanoparticle formation in the presence of oleic acid, implying that αS can interact with fatty acids and lipids in a similar manner. αS-related nanoparticles might play a role in lipid and fatty acid transport functions previously attributed to this protein.
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Affiliation(s)
- Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033, USA
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41
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Solid-state ¹³C NMR reveals annealing of raft-like membranes containing cholesterol by the intrinsically disordered protein α-Synuclein. J Mol Biol 2013; 425:2973-87. [PMID: 23583776 DOI: 10.1016/j.jmb.2013.04.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 03/14/2013] [Accepted: 04/02/2013] [Indexed: 11/20/2022]
Abstract
Misfolding and aggregation of the intrinsically disordered protein α-Synuclein (αS) in Lewy body plaques are characteristic markers of late-stage Parkinson's disease. It is well established that membrane binding is initiated at the N-terminus of the protein and affects biasing of conformational ensembles of αS. However, little is understood about the effect of αS on the membrane lipid bilayer. One hypothesis is that intrinsically disordered αS alters the structural properties of the membrane, thereby stabilizing the bilayer against fusion. Here, we used two-dimensional (13)C separated local-field NMR to study interaction of the wild-type α-Synuclein (wt-αS) or its N-terminal (1-25) amino acid sequence (N-αS) with a cholesterol-enriched ternary membrane system. This lipid bilayer mimics cellular raft-like domains in the brain that are proposed to be involved in neuronal membrane fusion. The two-dimensional dipolar-recoupling pulse sequence DROSS (dipolar recoupling on-axis with scaling and shape preservation) was implemented to measure isotropic (13)C chemical shifts and (13)C-(1)H residual dipolar couplings under magic-angle spinning. Site-specific changes in NMR chemical shifts and segmental order parameters indicate that both wt-αS and N-αS bind to the membrane interface and change lipid packing within raft-like membranes. Mean-torque modeling of (13)C-(1)H NMR order parameters shows that αS induces a remarkable thinning of the bilayer (≈6Å), accompanied by an increase in phospholipid cross-sectional area (≈10Å(2)). This perturbation is characterized as membrane annealing and entails structural remodeling of the raft-like liquid-ordered phase. We propose this process is implicated in regulation of synaptic membrane fusion that may be altered by aggregation of αS in Parkinson's disease.
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Schildknecht S, Gerding HR, Karreman C, Drescher M, Lashuel HA, Outeiro TF, Di Monte DA, Leist M. Oxidative and nitrative alpha-synuclein modifications and proteostatic stress: implications for disease mechanisms and interventions in synucleinopathies. J Neurochem 2013; 125:491-511. [PMID: 23452040 DOI: 10.1111/jnc.12226] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/21/2013] [Accepted: 02/21/2013] [Indexed: 12/22/2022]
Abstract
Alpha-synuclein (ASYN) is a major constituent of the typical protein aggregates observed in several neurodegenerative diseases that are collectively referred to as synucleinopathies. A causal involvement of ASYN in the initiation and progression of neurological diseases is suggested by observations indicating that single-point (e.g., A30P, A53T) or multiplication mutations of the gene encoding for ASYN cause early onset forms of Parkinson's disease (PD). The relative regional specificity of ASYN pathology is still a riddle that cannot be simply explained by its expression pattern. Also, transgenic over-expression of ASYN in mice does not recapitulate the typical dopaminergic neuronal death observed in PD. Thus, additional factors must contribute to ASYN-related toxicity. For instance, synucleinopathies are usually associated with inflammation and elevated levels of oxidative stress in affected brain areas. In turn, these conditions favor oxidative modifications of ASYN. Among these modifications, nitration of tyrosine residues, formation of covalent ASYN dimers, as well as methionine sulfoxidations are prominent examples that are observed in post-mortem PD brain sections. Oxidative modifications can affect ASYN aggregation, as well as its binding to biological membranes. This would affect neurotransmitter recycling, mitochondrial function and dynamics (fission/fusion), ASYN's degradation within a cell and, possibly, the transfer of modified ASYN to adjacent cells. Here, we propose a model on how covalent modifications of ASYN link energy stress, altered proteostasis, and oxidative stress, three major pathogenic processes involved in PD progression. Moreover, we hypothesize that ASYN may act physiologically as a catalytically regenerated scavenger of oxidants in healthy cells, thus performing an important protective role prior to the onset of disease or during aging.
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Affiliation(s)
- Stefan Schildknecht
- Department of Biology, Doerenkamp-Zbinden Chair for In vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany.
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Oxidation and nitration of α-synuclein and their implications in neurodegenerative diseases. Arch Biochem Biophys 2013; 533:25-32. [PMID: 23454347 DOI: 10.1016/j.abb.2013.02.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 02/07/2013] [Accepted: 02/15/2013] [Indexed: 01/14/2023]
Abstract
Synucleinopathies include Parkinson's disease, dementia with Lewy bodies, Lewy body variant of Alzheimer's disease and multiple system atrophy, among the most relevant diseases. All of these diseases are characterized by the presence of amyloid inclusions in neurons, which are rich in the aggregate α-synuclein protein. What is the biological mechanism concerned in the gain-of-function that implicates the participation of α-synuclein in these diseases? Post-translational modifications of α-synuclein induced by nitroxidative stress are a relevant hypothesis that may explain many of the experimental data. We will review the biophysical and biochemical properties of α-synuclein, methionine residues oxidation, nitration and oxidation of tyrosine residues in α-synuclein, and modifications of α-synuclein mediated by proteins and lipids under nitroxidative stress conditions. The biological consequences of these modifications are analyzed in terms of the properties of α-synuclein oligomerization and fibrillation, degradation of α-synuclein and the implications in the immunological response.
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44
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The Angiotensin II Type 2 Receptor in Brain Functions: An Update. Int J Hypertens 2012; 2012:351758. [PMID: 23320146 PMCID: PMC3540774 DOI: 10.1155/2012/351758] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 11/29/2012] [Indexed: 02/07/2023] Open
Abstract
Angiotensin II (Ang II) is the main active product of the renin-angiotensin system (RAS), mediating its action via two major receptors, namely, the Ang II type 1 (AT1) receptor and the type 2 (AT2) receptor. Recent results also implicate several other members of the renin-angiotensin system in various aspects of brain functions. The first aim of this paper is to summarize the current state of knowledge regarding the properties and signaling of the AT2 receptor, its expression in the brain, and its well-established effects. Secondly, we will highlight the potential role of the AT2 receptor in cognitive function, neurological disorders and in the regulation of appetite and the possible link with development of metabolic disorders. The potential utility of novel nonpeptide selective AT2 receptor ligands in clarifying potential roles of this receptor in physiology will also be discussed. If confirmed, these new pharmacological tools should help to improve impaired cognitive performance, not only through its action on brain microcirculation and inflammation, but also through more specific effects on neurons. However, the overall physiological relevance of the AT2 receptor in the brain must also consider the Ang IV/AT4 receptor.
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Mitochondrial dysfunction in Parkinson's disease: molecular mechanisms and pathophysiological consequences. EMBO J 2012; 31:3038-62. [PMID: 22735187 DOI: 10.1038/emboj.2012.170] [Citation(s) in RCA: 411] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/01/2012] [Indexed: 12/24/2022] Open
Abstract
Neurons are critically dependent on mitochondrial integrity based on specific morphological, biochemical, and physiological features. They are characterized by high rates of metabolic activity and need to respond promptly to activity-dependent fluctuations in bioenergetic demand. The dimensions and polarity of neurons require efficient transport of mitochondria to hot spots of energy consumption, such as presynaptic and postsynaptic sites. Moreover, the postmitotic state of neurons in combination with their exposure to intrinsic and extrinsic neuronal stress factors call for a high fidelity of mitochondrial quality control systems. Consequently, it is not surprising that mitochondrial alterations can promote neuronal dysfunction and degeneration. In particular, mitochondrial dysfunction has long been implicated in the etiopathogenesis of Parkinson's disease (PD), based on the observation that mitochondrial toxins can cause parkinsonism in humans and animal models. Substantial progress towards understanding the role of mitochondria in the disease process has been made by the identification and characterization of genes causing familial variants of PD. Studies on the function and dysfunction of these genes revealed that various aspects of mitochondrial biology appear to be affected in PD, comprising mitochondrial biogenesis, bioenergetics, dynamics, transport, and quality control.
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Robotta M, Hintze C, Schildknecht S, Zijlstra N, Jüngst C, Karreman C, Huber M, Leist M, Subramaniam V, Drescher M. Locally Resolved Membrane Binding Affinity of the N-Terminus of α-Synuclein. Biochemistry 2012; 51:3960-2. [DOI: 10.1021/bi300357a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marta Robotta
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Christian Hintze
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Stefan Schildknecht
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Niels Zijlstra
- Nanobiophysics,
MESA+ Institute
for Nanotechnology and MIRA Institute for Biomedical Technology and
Technical Medicine, University of Twente, 7500 AE Enschede, The Netherlands
| | - Christian Jüngst
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Christiaan Karreman
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Martina Huber
- Leiden Institute of Physics, University of Leiden, P.O. Box 9504, 2300 RA Leiden,
The Netherlands
| | - Marcel Leist
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Vinod Subramaniam
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
- Nanobiophysics,
MESA+ Institute
for Nanotechnology and MIRA Institute for Biomedical Technology and
Technical Medicine, University of Twente, 7500 AE Enschede, The Netherlands
| | - Malte Drescher
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
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Högen T, Levin J, Schmidt F, Caruana M, Vassallo N, Kretzschmar H, Bötzel K, Kamp F, Giese A. Two different binding modes of α-synuclein to lipid vesicles depending on its aggregation state. Biophys J 2012; 102:1646-55. [PMID: 22500765 DOI: 10.1016/j.bpj.2012.01.059] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 12/05/2011] [Accepted: 01/30/2012] [Indexed: 12/13/2022] Open
Abstract
Aggregation of α-synuclein is involved in the pathogenesis of Parkinson's disease (PD). Studies of in vitro aggregation of α-synuclein are rendered complex because of the formation of a heterogeneous population of oligomers. With the use of confocal single-molecule fluorescence techniques, we demonstrate that small aggregates (oligomers) of α-synuclein formed from unbound monomeric species in the presence of organic solvent (DMSO) and iron (Fe(3+)) ions have a high affinity to bind to model membranes, regardless of the lipid-composition or membrane curvature. This binding mode contrasts with the well-established membrane binding of α-synuclein monomers, which is accompanied with α-helix formation and requires membranes with high curvature, defects in the lipid packing, and/or negatively charged lipids. Additionally, we demonstrate that membrane-bound α-synuclein monomers are protected from aggregation. Finally, we identified compounds that potently dissolved vesicle-bound α-synuclein oligomers into monomers, leaving the lipid vesicles intact. As it is commonly believed that formation of oligomers is related PD progression, such compounds may provide a promising strategy for the design of novel therapeutic drugs in Parkinson's disease.
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Affiliation(s)
- Tobias Högen
- Neurologische Klinik, Klinikum Großhadern, Ludwig-Maximilians-Universität, Munich, Germany
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Tsigelny IF, Sharikov Y, Wrasidlo W, Gonzalez T, Desplats PA, Crews L, Spencer B, Masliah E. Role of α-synuclein penetration into the membrane in the mechanisms of oligomer pore formation. FEBS J 2012; 279:1000-13. [PMID: 22251432 DOI: 10.1111/j.1742-4658.2012.08489.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Parkinson's disease (PD) and dementia with Lewy bodies are common disorders of the aging population and characterized by the progressive accumulation of α-synuclein (α-syn) in the central nervous system. Aggregation of α-syn into oligomers with a ring-like appearance has been proposed to play a role in toxicity. However, the molecular mechanisms and the potential sequence of events involved in the formation of pore-like structures are unclear. We utilized computer modeling and cell-based studies to investigate the process of oligomerization of wild-type and A53T mutant α-syn in membranes. The studies suggest that α-syn penetrates the membrane rapidly, changing its conformation from α-helical towards a coiled structure. This penetration facilitates the incorporation of additional α-syn monomers in the complex, and the subsequent displacement of phospholipids and the formation of oligomers in the membrane. This process occurred more rapidly, and with a more favorable energy of interaction, for mutant A53T compared with wild-type α-syn. After 4 ns of simulation of the protein-membrane model, α-syn had penetrated through two-thirds of the membrane. By 9 ns, the penetration of the annular α-syn oligomers can result in the formation of pore-like structures that fully perforate the lipid bilayer. Experimental incubation of recombinant α-syn in synthetic membranes resulted in the formation of similar pore-like complexes. Moreover, mutant (A53T) α-syn had a greater tendency to accumulate in neuronal membrane fractions in cell cultures, resulting in greater neuronal permeability, as demonstrated with the calcein efflux assay. These studies provide a sequential molecular explanation for the process of α-syn oligomerization in the membrane, and support the role of formation of pore-like structures in the pathogenesis of the neurodegenerative process in PD.
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Affiliation(s)
- Igor F Tsigelny
- San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, USA
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Pfefferkorn CM, Jiang Z, Lee JC. Biophysics of α-synuclein membrane interactions. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1818:162-71. [PMID: 21819966 PMCID: PMC3249522 DOI: 10.1016/j.bbamem.2011.07.032] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/20/2011] [Accepted: 07/21/2011] [Indexed: 12/14/2022]
Abstract
Membrane proteins participate in nearly all cellular processes; however, because of experimental limitations, their characterization lags far behind that of soluble proteins. Peripheral membrane proteins are particularly challenging to study because of their inherent propensity to adopt multiple and/or transient conformations in solution and upon membrane association. In this review, we summarize useful biophysical techniques for the study of peripheral membrane proteins and their application in the characterization of the membrane interactions of the natively unfolded and Parkinson's disease (PD) related protein, α-synuclein (α-syn). We give particular focus to studies that have led to the current understanding of membrane-bound α-syn structure and the elucidation of specific membrane properties that affect α-syn-membrane binding. Finally, we discuss biophysical evidence supporting a key role for membranes and α-syn in PD pathogenesis. This article is part of a Special Issue entitled: Membrane protein structure and function.
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Affiliation(s)
- Candace M. Pfefferkorn
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Zhiping Jiang
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Jennifer C. Lee
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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Guo Y, Rosati B, Scarlata S. α-Synuclein increases the cellular level of phospholipase Cβ1. Cell Signal 2012; 24:1109-14. [PMID: 22286107 DOI: 10.1016/j.cellsig.2012.01.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 12/30/2011] [Accepted: 01/12/2012] [Indexed: 12/22/2022]
Abstract
α-Synuclein is a conserved protein that is a key component in neurodegenerative plaques [1,2]. α-Synuclein binds strongly to phospholipase Cβ (PLCβ) and promotes Ca2+ release in cells. Here, we show that expression of α-synuclein increases the cellular level of PLCβ1 in two neuronal cell lines: PC12 and SK-N-S-SH. The increase in PLCβ1 is not accompanied by changes in the level of RNA or in ubiquitination. Instead, we find that α-synuclein protects PLCβ1 from trypsin digestion and from degradation by the Ca(+2) activated protease calpain. Calpain removes the C-terminal region of the enzyme which mediates activation by Gα(q). We find that in SK-N-SH cells, α-synuclein reduced degradation of PLCβ1 by calpain during Ca2+ signaling allowing the enzyme to remain sensitive to Gα(q) activation. Taken together, our studies show that α-synuclein protects the integrity of PLCβ1 and its ability to be activated by Gα(q), which may in turn impact Ca2+ signaling.
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Affiliation(s)
- Yuanjian Guo
- Department of Physiology & Biophysics, Stony Book University, Stony Brook, NY 11794-8661, USA
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