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Mahbub NU, Islam MM, Hong ST, Chung HJ. Dysbiosis of the gut microbiota and its effect on α-synuclein and prion protein misfolding: consequences for neurodegeneration. Front Cell Infect Microbiol 2024; 14:1348279. [PMID: 38435303 PMCID: PMC10904658 DOI: 10.3389/fcimb.2024.1348279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 01/24/2024] [Indexed: 03/05/2024] Open
Abstract
Abnormal behavior of α-synuclein and prion proteins is the hallmark of Parkinson's disease (PD) and prion illnesses, respectively, being complex neurological disorders. A primary cause of protein aggregation, brain injury, and cognitive loss in prion illnesses is the misfolding of normal cellular prion proteins (PrPC) into an infectious form (PrPSc). Aggregation of α-synuclein causes disruptions in cellular processes in Parkinson's disease (PD), leading to loss of dopamine-producing neurons and motor symptoms. Alteration in the composition or activity of gut microbes may weaken the intestinal barrier and make it possible for prions to go from the gut to the brain. The gut-brain axis is linked to neuroinflammation; the metabolites produced by the gut microbiota affect the aggregation of α-synuclein, regulate inflammation and immunological responses, and may influence the course of the disease and neurotoxicity of proteins, even if their primary targets are distinct proteins. This thorough analysis explores the complex interactions that exist between the gut microbiota and neurodegenerative illnesses, particularly Parkinson's disease (PD) and prion disorders. The involvement of the gut microbiota, a complex collection of bacteria, archaea, fungi, viruses etc., in various neurological illnesses is becoming increasingly recognized. The gut microbiome influences neuroinflammation, neurotransmitter synthesis, mitochondrial function, and intestinal barrier integrity through the gut-brain axis, which contributes to the development and progression of disease. The review delves into the molecular mechanisms that underlie these relationships, emphasizing the effects of microbial metabolites such as bacterial lipopolysaccharides (LPS), and short-chain fatty acids (SCFAs) in regulating brain functioning. Additionally, it looks at how environmental influences and dietary decisions affect the gut microbiome and whether they could be risk factors for neurodegenerative illnesses. This study concludes by highlighting the critical role that the gut microbiota plays in the development of Parkinson's disease (PD) and prion disease. It also provides a promising direction for future research and possible treatment approaches. People afflicted by these difficult ailments may find hope in new preventive and therapeutic approaches if the role of the gut microbiota in these diseases is better understood.
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Affiliation(s)
- Nasir Uddin Mahbub
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, Jeonju, Republic of Korea
| | - Md Minarul Islam
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, Jeonju, Republic of Korea
| | - Seong-Tshool Hong
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, Jeonju, Republic of Korea
| | - Hea-Jong Chung
- Gwangju Center, Korea Basic Science Institute, Gwangju, Republic of Korea
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2
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FitzGerald EA, Vagrys D, Opassi G, Klein HF, Hamilton DJ, Talibov VO, Abramsson M, Moberg A, Lindgren MT, Holmgren C, Davis B, O'Brien P, Wijtmans M, Hubbard RE, de Esch IJP, Danielson UH. Multiplexed experimental strategies for fragment library screening against challenging drug targets using SPR biosensors. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2024; 29:40-51. [PMID: 37714432 DOI: 10.1016/j.slasd.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023]
Abstract
Surface plasmon resonance (SPR) biosensor methods are ideally suited for fragment-based lead discovery. However, generally applicable experimental procedures and detailed protocols are lacking, especially for structurally or physico-chemically challenging targets or when tool compounds are not available. Success depends on accounting for the features of both the target and the chemical library, purposely designing screening experiments for identification and validation of hits with desired specificity and mode-of-action, and availability of orthogonal methods capable of confirming fragment hits. The range of targets and libraries amenable to an SPR biosensor-based approach for identifying hits is considerably expanded by adopting multiplexed strategies, using multiple complementary surfaces or experimental conditions. Here we illustrate principles and multiplexed approaches for using flow-based SPR biosensor systems for screening fragment libraries of different sizes (90 and 1056 compounds) against a selection of challenging targets. It shows strategies for the identification of fragments interacting with 1) large and structurally dynamic targets, represented by acetyl choline binding protein (AChBP), a Cys-loop receptor ligand gated ion channel homologue, 2) targets in multi protein complexes, represented by lysine demethylase 1 and a corepressor (LSD1/CoREST), 3) structurally variable or unstable targets, represented by farnesyl pyrophosphate synthase (FPPS), 4) targets containing intrinsically disordered regions, represented by protein tyrosine phosphatase 1B (PTP1B), and 5) aggregation-prone proteins, represented by an engineered form of human tau (tau K18M). Practical considerations and procedures accounting for the characteristics of the proteins and libraries, and that increase robustness, sensitivity, throughput and versatility are highlighted. The study shows that the challenges for addressing these types of targets is not identification of potentially useful fragments per se, but establishing methods for their validation and evolution into leads.
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Affiliation(s)
- Edward A FitzGerald
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden; Beactica Therapeutics AB, Virdings allé 2, Uppsala, Sweden
| | - Darius Vagrys
- Vernalis (R&D) Ltd., Granta Park, Great Abington, Cambridge, United Kingdom; YSBL, Department of Chemistry, University of York, York, United Kingdom
| | - Giulia Opassi
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden
| | - Hanna F Klein
- Department of Chemistry, University of York, York, United Kingdom
| | - David J Hamilton
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | | | - Mia Abramsson
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden
| | | | | | | | - Ben Davis
- Vernalis (R&D) Ltd., Granta Park, Great Abington, Cambridge, United Kingdom
| | - Peter O'Brien
- Department of Chemistry, University of York, York, United Kingdom
| | - Maikel Wijtmans
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Roderick E Hubbard
- Vernalis (R&D) Ltd., Granta Park, Great Abington, Cambridge, United Kingdom; YSBL, Department of Chemistry, University of York, York, United Kingdom
| | - Iwan J P de Esch
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - U Helena Danielson
- Department of Chemistry - BMC, Uppsala University, Uppsala, Sweden; Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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3
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Ramalingam N, Brontesi L, Jin S, Selkoe DJ, Dettmer U. Dynamic reversibility of α-synuclein serine-129 phosphorylation is impaired in synucleinopathy models. EMBO Rep 2023; 24:e57145. [PMID: 37870370 PMCID: PMC10702791 DOI: 10.15252/embr.202357145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 09/28/2023] [Accepted: 10/06/2023] [Indexed: 10/24/2023] Open
Abstract
α-Synuclein phosphorylation at serine-129 (pS129) is a widely used surrogate marker of pathology in Parkinson's disease and other synucleinopathies. However, we recently demonstrated that phosphorylation of S129 is also a physiological activator of synaptic transmission. In a feed-forward fashion, neuronal activity triggers reversible pS129. Here, we show that Parkinson's disease-linked missense mutations in SNCA impact activity-dependent pS129. Under basal conditions, cytosol-enriched A30P, H50Q, and G51D mutant forms of α-synuclein exhibit reduced pS129 levels in rat primary cortical neurons. A53T pS129 levels are similar to wild-type, and E46K pS129 levels are higher. A30P and E46K mutants show impaired reversibility of pS129 after stimulation. For the engineered profoundly membrane-associated α-synuclein mutant "3K" (E35K + E46K + E61K), de-phosphorylation was virtually absent after blocking stimulation, implying that reversible pS129 is severely compromised. Importantly, pS129 excess resulting from proteasome inhibition is also associated with reduced reversibility by neuronal inhibition, kinase inhibition, or phosphatase activation. Our findings suggest that perturbed pS129 dynamics are probably a shared characteristic of pathology-associated α-synuclein, with possible implications for synucleinopathy treatment and diagnosis.
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Affiliation(s)
- Nagendran Ramalingam
- Ann Romney Center for Neurologic DiseasesBrigham and Women's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Lisa Brontesi
- Ann Romney Center for Neurologic DiseasesBrigham and Women's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Shan‐Xue Jin
- Ann Romney Center for Neurologic DiseasesBrigham and Women's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic DiseasesBrigham and Women's Hospital and Harvard Medical SchoolBostonMAUSA
| | - Ulf Dettmer
- Ann Romney Center for Neurologic DiseasesBrigham and Women's Hospital and Harvard Medical SchoolBostonMAUSA
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4
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Brontesi L, Imberdis T, Ramalingam N, Dettmer U. The effects of KTKEGV repeat motif and intervening ATVA sequence on α-synuclein solubility and assembly. J Neurochem 2023; 165:246-258. [PMID: 36625497 PMCID: PMC10211470 DOI: 10.1111/jnc.15763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 01/11/2023]
Abstract
Alpha-synuclein (αS), the key protein in Parkinson's disease, is typically described as an intrinsically disordered protein. Consistent with this notion, several context-dependent folding states may coexist in neurons. Unfolded soluble monomers, helical monomers at membranes and helical multimers (soluble or at membranes) have all been reported and may be in an equilibrium with each other. We previously found that αS can be stabilized in its membrane-associated monomeric form by genetically increasing the hydrophobicity of the membrane-embedded half of the αS helix. αS amphipathic helix formation at membranes is governed by up to nine 11-amino acid repeats with the core motif KTKEGV. However, this repeat is only imperfectly conserved; for example, it consists of KAKEGV in repeat #1, KTKEQV in repeat #5, and AVVTGV in the poorly conserved repeat #6. Here we explored the effect of perfecting the αS core repeat to nine times KTKEGV ("9KV") and found by sequential protein extraction that this engineered mutant accumulates in the cytosolic phase of neural cells. Intact-cell cross-linking trapped a part of the cytosolic portion at multimeric positions (30, 60, 80, 100 kDa). Thus, compared to wild-type αS, αS 9KV seems less prone to populating the membrane-associated monomeric form. Removing the "ATVA" intervening amino-acid sequence between repeats 4 and 5 slightly increased cytosolic localization while adding "ATVA" in between all repeats 1-8 caused αS to be trapped as a monomer in membrane fractions. Our results contribute to an ongoing debate on the dynamic structure of αS, highlighting that wild-type αS is unlikely to be fully multimeric/monomeric or fully cytosolic/membrane-associated in cells, but protein engineering can create αS variants that preferentially adopt a certain state. Overall, the imperfect nature of the KTKEGV repeat motifs and the presence of ATVA in between repeats 4 and 5 seem to prevent a strong cytosolic localization of αS and thus play a major role in the protein's ability to dynamically populate cytosolic vs. membrane-associated and monomeric vs. multimeric states.
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Affiliation(s)
| | | | - Nagendran Ramalingam
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115 USA
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5
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Maina KN, Smet-Nocca C, Bitan G. Using FRET-Based Biosensor Cells to Study the Seeding Activity of Tau and α-Synuclein. Methods Mol Biol 2023; 2551:125-145. [PMID: 36310201 PMCID: PMC9836052 DOI: 10.1007/978-1-0716-2597-2_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Two fluorescence resonance energy transfer (FRET)-based biosensor cell lines developed several years ago by the Diamond group (University of Texas, Southwestern) have allowed convenient, sensitive, and specific measurement of the intracellular aggregation of tau and α-synuclein following the addition of oligomer or small-aggregate "seeds" of these proteins from various sources, and an advancement relative to similar single-fluorophore systems. These biosensor cell lines allow researchers to both visualize the intracellular aggregates of tau or α-synuclein and measure intracellular aggregation with high sensitivity using a FRET signal in flow cytometry. Here we provide detailed protocols for generating seeds, culturing the biosensor cells, measuring intracellular aggregates by flow cytometry, and analyzing the results and discuss the utility of the technique with the aim of characterizing factors involved in the regulation of intracellular tau and α-synuclein aggregation.
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Affiliation(s)
- Katherine N Maina
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Caroline Smet-Nocca
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS EMR9002 Integrative Structural Biology, Lille, France
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
- Brain Research Institute, University of California, Los Angeles, CA, USA.
- Molecular Biology Institute, University of California, Los Angeles, CA, USA.
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6
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Hughes S, van Dop M, Kolsters N, van de Klashorst D, Pogosova A, Rijs AM. Using a Caenorhabditis elegans Parkinson's Disease Model to Assess Disease Progression and Therapy Efficiency. Pharmaceuticals (Basel) 2022; 15:512. [PMID: 35631338 PMCID: PMC9143865 DOI: 10.3390/ph15050512] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 12/12/2022] Open
Abstract
Despite Parkinson's Disease (PD) being the second most common neurodegenerative disease, treatment options are limited. Consequently, there is an urgent need to identify and screen new therapeutic compounds that slow or reverse the pathology of PD. Unfortunately, few new therapeutics are being produced, partly due to the low throughput and/or poor predictability of the currently used model organisms and in vivo screening methods. Our objective was to develop a simple and affordable platform for drug screening utilizing the nematode Caenorhabditis elegans. The effect of Levodopa, the "Gold standard" of PD treatment, was explored in nematodes expressing the disease-causing α-synuclein protein. We focused on two key hallmarks of PD: plaque formation and mobility. Exposure to Levodopa ameliorated the mobility defect in C. elegans, similar to people living with PD who take the drug. Further, long-term Levodopa exposure was not detrimental to lifespan. This C. elegans-based method was used to screen a selection of small-molecule drugs for an impact on α-synuclein aggregation and mobility, identifying several promising compounds worthy of further investigation, most notably Ambroxol. The simple methodology means it can be adopted in many labs to pre-screen candidate compounds for a positive impact on disease progression.
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Affiliation(s)
- Samantha Hughes
- HAN BioCentre, HAN University of Applied Sciences, Laan van Scheut 2, 6525 EM Nijmegen, The Netherlands; (M.v.D.); (N.K.); (D.v.d.K.); (A.P.)
- A-LIFE Amsterdam Institute for Life and Environment, Section Environmental Health and Toxicology, Vrije Univeristeit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Maritza van Dop
- HAN BioCentre, HAN University of Applied Sciences, Laan van Scheut 2, 6525 EM Nijmegen, The Netherlands; (M.v.D.); (N.K.); (D.v.d.K.); (A.P.)
| | - Nikki Kolsters
- HAN BioCentre, HAN University of Applied Sciences, Laan van Scheut 2, 6525 EM Nijmegen, The Netherlands; (M.v.D.); (N.K.); (D.v.d.K.); (A.P.)
| | - David van de Klashorst
- HAN BioCentre, HAN University of Applied Sciences, Laan van Scheut 2, 6525 EM Nijmegen, The Netherlands; (M.v.D.); (N.K.); (D.v.d.K.); (A.P.)
| | - Anastasia Pogosova
- HAN BioCentre, HAN University of Applied Sciences, Laan van Scheut 2, 6525 EM Nijmegen, The Netherlands; (M.v.D.); (N.K.); (D.v.d.K.); (A.P.)
| | - Anouk M. Rijs
- Division of BioAnalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Univeristeit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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7
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Oláh J, Szénási T, Lehotzky A, Norris V, Ovádi J. Challenges in Discovering Drugs That Target the Protein-Protein Interactions of Disordered Proteins. Int J Mol Sci 2022; 23:ijms23031550. [PMID: 35163473 PMCID: PMC8835748 DOI: 10.3390/ijms23031550] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 12/17/2022] Open
Abstract
Protein–protein interactions (PPIs) outnumber proteins and are crucial to many fundamental processes; in consequence, PPIs are associated with several pathological conditions including neurodegeneration and modulating them by drugs constitutes a potentially major class of therapy. Classically, however, the discovery of small molecules for use as drugs entails targeting individual proteins rather than targeting PPIs. This is largely because discovering small molecules to modulate PPIs has been seen as extremely challenging. Here, we review the difficulties and limitations of strategies to discover drugs that target PPIs directly or indirectly, taking as examples the disordered proteins involved in neurodegenerative diseases.
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Affiliation(s)
- Judit Oláh
- Institute of Enzymology, Research Centre for Natural Sciences, ELKH, 1117 Budapest, Hungary; (J.O.); (T.S.); (A.L.)
| | - Tibor Szénási
- Institute of Enzymology, Research Centre for Natural Sciences, ELKH, 1117 Budapest, Hungary; (J.O.); (T.S.); (A.L.)
| | - Attila Lehotzky
- Institute of Enzymology, Research Centre for Natural Sciences, ELKH, 1117 Budapest, Hungary; (J.O.); (T.S.); (A.L.)
| | - Victor Norris
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen, 76821 Mont Saint Aignan, France;
| | - Judit Ovádi
- Institute of Enzymology, Research Centre for Natural Sciences, ELKH, 1117 Budapest, Hungary; (J.O.); (T.S.); (A.L.)
- Correspondence:
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8
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Kayed R, Dettmer U, Lesné SE. Soluble endogenous oligomeric α-synuclein species in neurodegenerative diseases: Expression, spreading, and cross-talk. JOURNAL OF PARKINSON'S DISEASE 2021; 10:791-818. [PMID: 32508330 PMCID: PMC7458533 DOI: 10.3233/jpd-201965] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
There is growing recognition in the field of neurodegenerative diseases that mixed proteinopathies are occurring at greater frequency than originally thought. This is particularly true for three amyloid proteins defining most of these neurological disorders, amyloid-beta (Aβ), tau, and alpha-synuclein (αSyn). The co-existence and often co-localization of aggregated forms of these proteins has led to the emergence of concepts positing molecular interactions and cross-seeding between Aβ, tau, and αSyn aggregates. Amongst this trio, αSyn has received particular attention in this context during recent years due to its ability to modulate Aβ and tau aggregation in vivo, to interact at a molecular level with Aβ and tau in vivo and to cross-seed tau in mice. Here we provide a comprehensive, critical, and accessible review about the expression, role and nature of endogenous soluble αSyn oligomers because of recent developments in the understanding of αSyn multimerization, misfolding, aggregation, cross-talk, spreading and cross-seeding in neurodegenerative disorders, including Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, Alzheimer's disease, and Huntington's disease. We will also discuss our current understanding about the relative toxicity of endogenous αSyn oligomers in vivo and in vitro, and introduce potential opportunities to counter their deleterious effects.
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Affiliation(s)
- Rakez Kayed
- Departments of Neurology & Neuroscience & Cell Biology & Anatomy, University of Texas Medical Branch Galveston, Galveston, TX, USA,George and Cynthia Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch Galveston, Galveston, TX, USA
| | - Ulf Dettmer
- Department of Neurology, Harvard Medical School, Boston, MA, USA,Ann Romney Center for Neurologic Diseases, Harvard Medical School, Boston, MA, USA
| | - Sylvain E. Lesné
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA,Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA,Correspondence to: Sylvain E. Lesné, PhD, University of Minnesota, Wallin Medical Biosciences Building (Room 4-114), 2101 Sixth Street SE, CDC 2641, Minneapolis, MN 55414, USA. Tel.: +1 612 626 8341; E-mail: ; Website: https://lesnelab.org
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9
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Kim TE, Newman AJ, Imberdis T, Brontesi L, Tripathi A, Ramalingam N, Fanning S, Selkoe D, Dettmer U. Excess membrane binding of monomeric alpha-, beta-, and gamma-synuclein is invariably associated with inclusion formation and toxicity. Hum Mol Genet 2021; 30:2332-2346. [PMID: 34254125 PMCID: PMC8600006 DOI: 10.1093/hmg/ddab188] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/15/2021] [Accepted: 07/05/2021] [Indexed: 11/27/2022] Open
Abstract
α-Synuclein (αS) has been well-documented to play a role in human synucleinopathies such as Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). First, the lesions found in PD/DLB brains—Lewy bodies and Lewy neurites—are rich in aggregated αS. Second, genetic evidence links missense mutations and increased αS expression to familial forms of PD/DLB. Third, toxicity and cellular stress can be caused by αS under certain experimental conditions. In contrast, the homologs β-synuclein (βS) and γ-synuclein (γS) are not typically found in Lewy bodies/neurites, have not been clearly linked to brain diseases and have been largely non-toxic in experimental settings. In αS, the so-called non-amyloid-β component of plaques (NAC) domain, constituting amino acids 61–95, has been identified to be critical for aggregation in vitro. This domain is partially absent in βS and only incompletely conserved in γS, which could explain why both homologs do not cause disease. However, αS in vitro aggregation and cellular toxicity have not been firmly linked experimentally, and it has been proposed that excess αS membrane binding is sufficient to induce neurotoxicity. Indeed, recent characterizations of Lewy bodies have highlighted the accumulation of lipids and membranous organelles, raising the possibility that βS and γS could also become neurotoxic if they were more prone to membrane/lipid binding. Here, we increased βS and γS membrane affinity by strategic point mutations and demonstrate that these proteins behave like membrane-associated monomers, are cytotoxic and form round cytoplasmic inclusions that can be prevented by inhibiting stearoyl-CoA desaturase.
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Affiliation(s)
- Tae-Eun Kim
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Andrew J Newman
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Thibaut Imberdis
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Lisa Brontesi
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Arati Tripathi
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Nagendran Ramalingam
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Saranna Fanning
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Dennis Selkoe
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
| | - Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
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10
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Crowded organelles, lipid accumulation, and abnormal membrane tubulation in cellular models of enhanced α-synuclein membrane interaction. Brain Res 2021; 1758:147349. [PMID: 33571519 DOI: 10.1016/j.brainres.2021.147349] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/13/2021] [Accepted: 02/02/2021] [Indexed: 11/24/2022]
Abstract
Previous work from our group showed that certain engineered missense mutations to the α-synuclein (αS) KTKEGV repeat motifs abrogate the protein's ability to form native multimers. The resultant excess monomers accumulate in lipid-membrane-rich inclusions associated with neurotoxicity exceeding that of natural familial Parkinson's disease mutants such as E46K. We presented an initial characterization of the lipid-rich inclusions and found similarities to the αS- and vesicle-rich inclusions that form in baker's yeast when αS is expressed. We also discussed, with some caution, a possible role of membrane-rich inclusions as precursors to filamentous Lewy bodies, the widely accepted hallmark pathology of Parkinson's disease and other synucleinopathies. In the meantime, advances in the microscopic characterization of Lewy bodies have highlighted the presence of crowded organelles and lipid membranes in addition to αS accumulation. This prompted us to revisit the αS inclusions caused by our repeat motif variants in neuroblastoma cells. In addition to our previous characterization, we found that these inclusions can often be seen by brightfield microscopy, overlap with endogenous vesicle markers in immunofluorescence experiments, stain positive for lipid dyes, and can be found to be closely associated with mitochondria. We also observed abnormal tubulation of membranes, which was subtle in inducible lines and pronounced in cells that transiently expressed high amounts of the highly disruptive KTKEGV motif mutant "KLKEGV". Membrane tubulation had been reported before as an αS activity in reductionist systems. Our in-cellulo demonstration now suggests that this mechanism could possibly be a relevant aspect of aberrant αS behavior in cells.
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11
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Ramalingam N, Dettmer U. Temperature is a key determinant of alpha- and beta-synuclein membrane interactions in neurons. J Biol Chem 2021; 296:100271. [PMID: 33428933 PMCID: PMC7949061 DOI: 10.1016/j.jbc.2021.100271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 02/02/2023] Open
Abstract
Aggregation of α-synuclein (αS) leads to the hallmark neuropathology of Parkinson's disease (PD) and related synucleinopathies. αS has been described to exist in both cytosolic and membrane-associated forms, the relative abundance of which has remained unsettled. To study αS under the most relevant conditions by a quantitative method, we cultured and matured rodent primary cortical neurons for >17 days and determined αS cytosol:membrane distribution via centrifugation-free sequential extractions based on the weak ionic detergent digitonin. We noticed that at lower temperatures (4 °C or room temperature), αS was largely membrane-associated. At 37 °C, however, αS solubility was markedly increased. In contrast, the extraction of control proteins (GAPDH, cytosolic; calnexin, membrane) was not affected by temperature. When we compared the relative distribution of the synuclein homologs αS and β-synuclein (βS) under various conditions that differed in temperature and digitonin concentration (200-1200 μg/ml), we consistently found αS to be more membrane-associated than βS. Both proteins, however, exhibited temperature-dependent membrane binding. Under the most relevant conditions (37 °C and 800 μg/ml digitonin, i.e., the lowest digitonin concentration that extracted cytosolic GAPDH to near completion), cytosolic distribution was 49.8% ± 9.0% for αS and 63.6% ± 6.6% for βS. PD-linked αS A30P was found to be largely cytosolic, confirming previous studies that had used different methods. Our work highlights the dynamic nature of cellular synuclein behavior and has important implications for protein-biochemical and cell-biological studies of αS proteostasis, such as testing the effects of genetic and pharmacological manipulations.
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Affiliation(s)
- Nagendran Ramalingam
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
| | - Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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Sears JC, Broadie K. FMRP-PKA Activity Negative Feedback Regulates RNA Binding-Dependent Fibrillation in Brain Learning and Memory Circuitry. Cell Rep 2020; 33:108266. [PMID: 33053340 PMCID: PMC7590955 DOI: 10.1016/j.celrep.2020.108266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 09/07/2020] [Accepted: 09/22/2020] [Indexed: 11/29/2022] Open
Abstract
Fragile X mental retardation protein (FMRP) promotes cyclic AMP (cAMP) signaling. Using an in vivo protein kinase A activity sensor (PKA-SPARK), we find that Drosophila FMRP (dFMRP) and human FMRP (hFMRP) enhance PKA activity in a central brain learning and memory center. Increasing neuronal PKA activity suppresses FMRP in Kenyon cells, demonstrating an FMRP-PKA negative feedback loop. A patient-derived R140Q FMRP point mutation mislocalizes PKA-SPARK activity, whereas deletion of the RNA-binding argi-nine-glycine-glycine (RGG) box (hFMRP-ΔRGG) produces fibrillar PKA-SPARK assemblies colocalizing with ribonucleoprotein (RNP) and aggregation (thioflavin T) markers, demonstrating fibrillar partitioning of cytosolic protein aggregates. hFMRP-ΔRGG reduces dFMRP levels, indicating RGG-independent regulation. Short-term hFMRP-ΔRGG induction produces activated PKA-SPARK puncta, whereas long induction drives fibrillar assembly. Elevated temperature disassociates hFMRP-ΔRGG aggregates and blocks activated PKA-SPARK localization. These results suggest that FMRP regulates compartmentalized signaling via complex assembly, directing PKA activity localization, with FMRP RGG box RNA binding restricting separation via low-complexity interactions. FMRP is required for brain cAMP induction and cAMP-dependent PKA activation, but the FMRP mechanism is uncharacterized. Sears and Broadie test FXS patient-derived and FMRP domain-deficient mutants to reveal conserved FMRP functions regulating PKA activation, subcellular localization, and reversible partitioning into elongated fibrillar assemblies in brain learning/ memory circuit neurons.
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Affiliation(s)
- James C Sears
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN 37235, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
| | - Kendal Broadie
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN 37235, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37235, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37235, USA.
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Maackiain Ameliorates 6-Hydroxydopamine and SNCA Pathologies by Modulating the PINK1/Parkin Pathway in Models of Parkinson's Disease in Caenorhabditis elegans and the SH-SY5Y Cell Line. Int J Mol Sci 2020; 21:ijms21124455. [PMID: 32585871 PMCID: PMC7352553 DOI: 10.3390/ijms21124455] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/18/2020] [Accepted: 06/21/2020] [Indexed: 02/07/2023] Open
Abstract
The movement disorder Parkinson's disease (PD) is the second most frequently diagnosed neurodegenerative disease, and is associated with aging, the environment, and genetic factors. The intracellular aggregation of α-synuclein and the loss of dopaminergic neurons in the substantia nigra pars compacta are the pathological hallmark of PD. At present, there is no successful treatment for PD. Maackiain (MK) is a flavonoid extracted from dried roots of Sophora flavescens Aiton. MK has emerged as a novel agent for PD treatment that acts by inhibiting monoamine oxidase B. In this study, we assessed the neuroprotective potential of MK in Caenorhabditis elegans and investigated possible mechanism of this neuroprotection in the human SH-SY5Y cell line. We found that MK significantly reduced dopaminergic neuron damage in 6-hydroxydopamine (6-OHDA)-exposed worms of the BZ555 strain, with corresponding improvements in food-sensing behavior and life-span. In transgenic worms of strain NL5901 treated with 0.25 mM MK, the accumulation of α-synuclein was diminished by 27% (p < 0.01) compared with that in untreated worms. Moreover, in worms and the SH-SY5Y cell line, we confirmed that the mechanism of MK-mediated protection against PD pathology may include blocking apoptosis, enhancing the ubiquitin-proteasome system, and augmenting autophagy by increasing PINK1/parkin expression. The use of small interfering RNA to downregulate parkin expression in vivo and in vitro could reverse the benefits of MK in PD models. MK may have considerable therapeutic applications in PD.
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Penke B, Szűcs M, Bogár F. Oligomerization and Conformational Change Turn Monomeric β-Amyloid and Tau Proteins Toxic: Their Role in Alzheimer's Pathogenesis. Molecules 2020; 25:molecules25071659. [PMID: 32260279 PMCID: PMC7180792 DOI: 10.3390/molecules25071659] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
The structural polymorphism and the physiological and pathophysiological roles of two important proteins, β-amyloid (Aβ) and tau, that play a key role in Alzheimer's disease (AD) are reviewed. Recent results demonstrate that monomeric Aβ has important physiological functions. Toxic oligomeric Aβ assemblies (AβOs) may play a decisive role in AD pathogenesis. The polymorph fibrillar Aβ (fAβ) form has a very ordered cross-β structure and is assumed to be non-toxic. Tau monomers also have several important physiological actions; however, their oligomerization leads to toxic oligomers (TauOs). Further polymerization results in probably non-toxic fibrillar structures, among others neurofibrillary tangles (NFTs). Their structure was determined by cryo-electron microscopy at atomic level. Both AβOs and TauOs may initiate neurodegenerative processes, and their interactions and crosstalk determine the pathophysiological changes in AD. TauOs (perhaps also AβO) have prionoid character, and they may be responsible for cell-to-cell spreading of the disease. Both extra- and intracellular AβOs and TauOs (and not the previously hypothesized amyloid plaques and NFTs) may represent the novel targets of AD drug research.
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Affiliation(s)
- Botond Penke
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
- Correspondence:
| | - Mária Szűcs
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
| | - Ferenc Bogár
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
- MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Hungary
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Neuroinflammation and Neurogenesis in Alzheimer's Disease and Potential Therapeutic Approaches. Int J Mol Sci 2020; 21:ijms21030701. [PMID: 31973106 PMCID: PMC7037892 DOI: 10.3390/ijms21030701] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/17/2020] [Accepted: 01/19/2020] [Indexed: 12/17/2022] Open
Abstract
In adult brain, new neurons are generated throughout adulthood in the subventricular zone and the dentate gyrus; this process is commonly known as adult neurogenesis. The regulation or modulation of adult neurogenesis includes various intrinsic pathways (signal transduction pathway and epigenetic or genetic modulation pathways) or extrinsic pathways (metabolic growth factor modulation, vascular, and immune system pathways). Altered neurogenesis has been identified in Alzheimer's disease (AD), in both human AD brains and AD rodent models. The exact mechanism of the dysregulation of adult neurogenesis in AD has not been completely elucidated. However, neuroinflammation has been demonstrated to alter adult neurogenesis. The presence of various inflammatory components, such as immune cells, cytokines, or chemokines, plays a role in regulating the survival, proliferation, and maturation of neural stem cells. Neuroinflammation has also been considered as a hallmark neuropathological feature of AD. In this review, we summarize current, state-of-the art perspectives on adult neurogenesis, neuroinflammation, and the relationship between these two phenomena in AD. Furthermore, we discuss the potential therapeutic approaches, focusing on the anti-inflammatory and proneurogenic interventions that have been reported in this field.
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16
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Parkinson's disease: proteinopathy or lipidopathy? NPJ PARKINSONS DISEASE 2020; 6:3. [PMID: 31909184 PMCID: PMC6941970 DOI: 10.1038/s41531-019-0103-7] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/02/2019] [Indexed: 12/16/2022]
Abstract
Lipids play a more significant role in Parkinson’s disease and its related brain disorders than is currently recognized, supporting a “lipid cascade”. The 14 kDa protein α-synuclein (αS) is strongly associated with Parkinson’s disease (PD), dementia with Lewy bodies (DLB), other synucleinopathies such as multiple system atrophy, and even certain forms of Alzheimer’s disease. Rigorously deciphering the biochemistry of αS in native systems is the key to developing treatments. αS is highly expressed in the brain, the second most lipid-rich organ, and has been proposed to be a lipid-binding protein that physiologically interacts with phospholipids and fatty acids (FAs). αS-rich cytoplasmic inclusions called Lewy bodies and Lewy neurites are the hallmark lesions of synucleinopathies. Excess αS–membrane interactions may trigger proteinaceous αS aggregation by stimulating its primary nucleation. However, αS may also exert its toxicity prior to or independent of its self-aggregation, e.g., via excessive membrane interactions, which may be promoted by certain lipids and FAs. A complex αS-lipid landscape exists, which comprises both physiological and pathological states of αS. As novel insights about the composition of Lewy lesions occur, new lipid-related PD drug candidates emerge, and genome-wide association studies (GWAS) increasingly validate new hits in lipid-associated pathways, it seems timely to review our current knowledge of lipids in PD and consider the roles for these pathways in synucleinopathies.αS ↔ lipid interplay: aspects of cellular αS homeostasis (blue oval), aspects of lipid homeostasis (green oval), and overlapping aspects. Pathological states are labeled in red. Simplified schematic of both select αS and select lipid species. Several existing publications suggest αS effects on lipids and vice versa, as indicated by arrows. DG diglyceride, ER endoplasmic reticulum, FA fatty acid, LD, lipid droplet, TG triglyceride. ![]()
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Poulson BG, Szczepski K, Lachowicz JI, Jaremko L, Emwas AH, Jaremko M. Aggregation of biologically important peptides and proteins: inhibition or acceleration depending on protein and metal ion concentrations. RSC Adv 2019; 10:215-227. [PMID: 35492549 PMCID: PMC9047971 DOI: 10.1039/c9ra09350h] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 12/14/2019] [Indexed: 01/03/2023] Open
Abstract
The process of aggregation of proteins and peptides is dependent on the concentration of proteins, and the rate of aggregation can be altered by the presence of metal ions, but this dependence is not always a straightforward relationship. In general, aggregation does not occur under normal physiological conditions, yet it can be induced in the presence of certain metal ions. However, the extent of the influence of metal ion interactions on protein aggregation has not yet been fully comprehended. A consensus has thus been difficult to reach because the acceleration/inhibition of the aggregation of proteins in the presence of metal ions depends on several factors such as pH and the concentration of the aggregated proteins involved as well as metal concentration level of metal ions. Metal ions, like Cu2+, Zn2+, Pb2+ etc. may either accelerate or inhibit aggregation simply because the experimental conditions affect the behavior of biomolecules. It is clear that understanding the relationship between metal ion concentration and protein aggregation will prove useful for future scientific applications. This review focuses on the dependence of the aggregation of selected important biomolecules (peptides and proteins) on metal ion concentrations. We review proteins that are prone to aggregation, the result of which can cause serious neurodegenerative disorders. Furthering our understanding of the relationship between metal ion concentration and protein aggregation will prove useful for future scientific applications, such as finding therapies for neurodegenerative diseases.
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Affiliation(s)
- Benjamin Gabriel Poulson
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
| | - Kacper Szczepski
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
| | - Joanna Izabela Lachowicz
- Department of Medical Sciences and Public Health, University of Cagliari, Cittadella Universitaria 09042 Monserrato Italy
| | - Lukasz Jaremko
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
| | - Abdul-Hamid Emwas
- Core Labs, King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
| | - Mariusz Jaremko
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
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