1
|
Chen S, Barritt JD, Cascella R, Bigi A, Cecchi C, Banchelli M, Gallo A, Jarvis JA, Chiti F, Dobson CM, Fusco G, De Simone A. Structure-Toxicity Relationship in Intermediate Fibrils from α-Synuclein Condensates. J Am Chem Soc 2024; 146:10537-10549. [PMID: 38567991 PMCID: PMC11027145 DOI: 10.1021/jacs.3c14703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 04/18/2024]
Abstract
The aberrant aggregation of α-synuclein (αS) into amyloid fibrils is associated with a range of highly debilitating neurodegenerative conditions, including Parkinson's disease. Although the structural properties of mature amyloids of αS are currently understood, the nature of transient protofilaments and fibrils that appear during αS aggregation remains elusive. Using solid-state nuclear magnetic resonance (ssNMR), cryogenic electron microscopy (cryo-EM), and biophysical methods, we here characterized intermediate amyloid fibrils of αS forming during the aggregation from liquid-like spherical condensates to mature amyloids adopting the structure of pathologically observed aggregates. These transient amyloid intermediates, which induce significant levels of cytotoxicity when incubated with neuronal cells, were found to be stabilized by a small core in an antiparallel β-sheet conformation, with a disordered N-terminal region of the protein remaining available to mediate membrane binding. In contrast, mature amyloids that subsequently appear during the aggregation showed different structural and biological properties, including low levels of cytotoxicity, a rearranged structured core embedding also the N-terminal region, and a reduced propensity to interact with the membrane. The characterization of these two fibrillar forms of αS, and the use of antibodies and designed mutants, enabled us to clarify the role of critical structural elements endowing intermediate amyloid species with the ability to interact with membranes and induce cytotoxicity.
Collapse
Affiliation(s)
- Serene
W. Chen
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, U.K.
| | - Joseph D. Barritt
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, U.K.
| | - Roberta Cascella
- Department
of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence 50134, Italy
| | - Alessandra Bigi
- Department
of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence 50134, Italy
| | - Cristina Cecchi
- Department
of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence 50134, Italy
| | - Martina Banchelli
- Institute
of Applied Physics “Nello Carrara” National Research
Council of Italy, Sesto Fiorentino, Florence 50019, Italy
| | - Angelo Gallo
- Department
of Chemistry, University of Turin, Turin 10124, Italy
| | - James A. Jarvis
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, U.K.
- Randall
Centre for Cell and Molecular Biophysics and Centre for Biomolecular
Spectroscopy, King’s College London, London SE1 9RT, U.K.
| | - Fabrizio Chiti
- Department
of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence 50134, Italy
| | | | - Giuliana Fusco
- Department
of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
- Department
of Pharmacy, University of Naples, Naples 80131, Italy
| | - Alfonso De Simone
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, U.K.
- Department
of Pharmacy, University of Naples, Naples 80131, Italy
| |
Collapse
|
2
|
Naaman E, Qarawani A, Ben-Zvi Elimelech R, Harel M, Sigal-Dror S, Safuri S, Smirnovas V, Baronaite I, Romanova NV, Morozova-Roche LA, Zayit-Soudry S. The Surprising Nonlinear Effects of S100A9 Proteins in the Retina. ACS Chem Neurosci 2024; 15:735-744. [PMID: 38324770 DOI: 10.1021/acschemneuro.3c00650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024] Open
Abstract
Age-related macular degeneration (AMD) is a complex disease in which inflammation is implicated as a key factor but the precise molecular mechanisms are poorly understood. AMD lesions contain an excess of the pro-inflammatory S100A9 protein, but its retinal significance was yet unexplored. S100A9 was shown to be intrinsically amyloidogenic in vitro and in vivo. Here, we hypothesized that the retinal effects of S100A9 are related to its supramolecular conformation. ARPE-19 cultures were treated with native dimeric and fibrillar S100A9 preparations, and cell viability was determined. Wild-type rats were treated intravitreally with the S100A9 solutions in the right eye and with the vehicle in the left. Retinal function was assessed longitudinally by electroretinography (ERG), comparing the amplitudes and configurations for each intervention. Native S100A9 had no impact on cellular viability in vitro or on the retinal function in vivo. Despite dispersed intracellular uptake, fibrillar S100A9 did not decrease ARPE-19 cell viability. In contrast, S100A9 fibrils impaired retinal function in vivo following intravitreal injection in rats. Intriguingly, low-dose fibrillar S100A9 induced contrasting in vivo effects, significantly increasing the ERG responses, particularly over 14 days postinjection. The retinal effects of S100A9 were further characterized by glial and microglial cell activation. We provide the first indication for the retinal effects of S100A9, showing that its fibrils inflicted retinal dysfunction and glial activation in vivo, while low dose of the same assemblies resulted in an unpredicted enhancement of the ERG amplitudes. These nonlinear responses highlight the consequences of self-assembly of S100A9 and provide insight into its pathophysiological and possibly physiological roles in the retina.
Collapse
Affiliation(s)
- Efrat Naaman
- Department of Ophthalmology, Rambam Health Care Campus, Haifa 3109601, Israel
- Clinical Research Institute, Rambam Health Care Campus, Haifa 3109601, Israel
| | - Amanda Qarawani
- Clinical Research Institute, Rambam Health Care Campus, Haifa 3109601, Israel
- Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa 69094, Israel
| | - Rony Ben-Zvi Elimelech
- Clinical Research Institute, Rambam Health Care Campus, Haifa 3109601, Israel
- Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa 69094, Israel
| | - Michal Harel
- Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa 69094, Israel
| | - Shahaf Sigal-Dror
- Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa 69094, Israel
| | - Shadi Safuri
- Department of Ophthalmology, Rambam Health Care Campus, Haifa 3109601, Israel
- Clinical Research Institute, Rambam Health Care Campus, Haifa 3109601, Israel
| | - Vytautas Smirnovas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius LT-10257, Lithuania
| | - Ieva Baronaite
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius LT-10257, Lithuania
| | - Nina V Romanova
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-90781, Sweden
| | | | - Shiri Zayit-Soudry
- Department of Ophthalmology, Rambam Health Care Campus, Haifa 3109601, Israel
- Clinical Research Institute, Rambam Health Care Campus, Haifa 3109601, Israel
- Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa 69094, Israel
| |
Collapse
|
3
|
Bigi A, Napolitano L, Vadukul DM, Chiti F, Cecchi C, Aprile FA, Cascella R. A single-domain antibody detects and neutralises toxic Aβ 42 oligomers in the Alzheimer's disease CSF. Alzheimers Res Ther 2024; 16:13. [PMID: 38238842 PMCID: PMC10795411 DOI: 10.1186/s13195-023-01361-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/29/2023] [Indexed: 01/22/2024]
Abstract
BACKGROUND Amyloid-β42 (Aβ42) aggregation consists of a complex chain of nucleation events producing soluble oligomeric intermediates, which are considered the major neurotoxic agents in Alzheimer's disease (AD). Cerebral lesions in the brain of AD patients start to develop 20 years before symptom onset; however, no preventive strategies, effective treatments, or specific and sensitive diagnostic tests to identify people with early-stage AD are currently available. In addition, the isolation and characterisation of neurotoxic Aβ42 oligomers are particularly difficult because of their transient and heterogeneous nature. To overcome this challenge, a rationally designed method generated a single-domain antibody (sdAb), named DesAb-O, targeting Aβ42 oligomers. METHODS We investigated the ability of DesAb-O to selectively detect preformed Aβ42 oligomers both in vitro and in cultured neuronal cells, by using dot-blot, ELISA immunoassay and super-resolution STED microscopy, and to counteract the toxicity induced by the oligomers, monitoring their interaction with neuronal membrane and the resulting mitochondrial impairment. We then applied this approach to CSF samples (CSFs) from AD patients as compared to age-matched control subjects. RESULTS DesAb-O was found to selectively detect synthetic Aβ42 oligomers both in vitro and in cultured cells, and to neutralise their associated neuronal dysfunction. DesAb-O can also identify Aβ42 oligomers present in the CSFs of AD patients with respect to healthy individuals, and completely prevent cell dysfunction induced by the administration of CSFs to neuronal cells. CONCLUSIONS Taken together, our data indicate a promising method for the improvement of an early diagnosis of AD and for the generation of novel therapeutic approaches based on sdAbs for the treatment of AD and other devastating neurodegenerative conditions.
Collapse
Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - Liliana Napolitano
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - Devkee M Vadukul
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - Francesco A Aprile
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy.
| |
Collapse
|
4
|
Sun C, Slade L, Mbonu P, Ordner H, Mitchell C, Mitchell M, Liang FC. Membrane protein chaperone and sodium chloride modulate the kinetics and morphology of amyloid beta aggregation. FEBS J 2024; 291:158-176. [PMID: 37786925 DOI: 10.1111/febs.16967] [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: 12/13/2022] [Revised: 07/04/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
Protein aggregation is a biological phenomenon caused by the accumulation of misfolded proteins. Amyloid beta (Aβ) peptides are derived from the cleavage of a larger membrane protein molecule and accumulate to form plaques extracellularly. According to the amyloid hypothesis, accumulation of Aβ aggregates in the brain is primarily responsible for the pathogenesis of Alzheimer's disease (AD). Therefore, the disassembly of Aβ aggregates may provide opportunities for alleviating or treating AD. Here, we show that the novel protein targeting machinery from chloroplast, chloroplast signal recognition particle 43 (cpSRP43), is an ATP-independent membrane protein chaperone that can both prevent and reverse Aβ aggregation effectively. Using of thioflavin T dye, we obtained the aggregation kinetics of Aβ aggregation and determined that the chaperone prevents Aβ aggregation in a concentration-dependent manner. Size exclusion chromatography and sedimentation assays showed that 10-fold excess of cpSRP43 can keep Aβ in the soluble monomeric form. Electron microscopy showed that the fibril structure was disrupted in the presence of this chaperone. Importantly, cpSRP43 utilizes the binding energy to actively remodel the preformed Aβ aggregates without assistance by a co-chaperone and ATP, emphasizing its unique function among protein chaperones. Moreover, when sodium chloride concentration is higher than 25 mm, the Aβ aggregation rate increases drastically to form tightly associated aggregates and generate more oligomers. Our results demonstrate that the presence of cpSRP43 and low NaCl levels inhibit or retard Aβ peptide aggregation, potentially opening new avenues to strategically develop an effective treatment for AD.
Collapse
Affiliation(s)
- Christopher Sun
- Department of Biology, Midwestern State University, Wichita Falls, TX, USA
| | - Leah Slade
- Department of Chemistry, Midwestern State University, Wichita Falls, TX, USA
| | - Prisca Mbonu
- Department of Biology, Midwestern State University, Wichita Falls, TX, USA
| | - Hunter Ordner
- Department of Chemistry, Midwestern State University, Wichita Falls, TX, USA
| | - Connor Mitchell
- Department of Chemistry, Midwestern State University, Wichita Falls, TX, USA
| | - Matthew Mitchell
- Department of Chemistry, Midwestern State University, Wichita Falls, TX, USA
| | - Fu-Cheng Liang
- Department of Chemistry, Midwestern State University, Wichita Falls, TX, USA
| |
Collapse
|
5
|
Cascella R, Banchelli M, Abolghasem Ghadami S, Ami D, Gagliani MC, Bigi A, Staderini T, Tampellini D, Cortese K, Cecchi C, Natalello A, Adibi H, Matteini P, Chiti F. An in situ and in vitro investigation of cytoplasmic TDP-43 inclusions reveals the absence of a clear amyloid signature. Ann Med 2023; 55:72-88. [PMID: 36495262 PMCID: PMC9746631 DOI: 10.1080/07853890.2022.2148734] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Introduction: Several neurodegenerative conditions are associated with a common histopathology within neurons of the central nervous system, consisting of the deposition of cytoplasmic inclusions of TAR DNA-binding protein 43 (TDP-43). Such inclusions have variably been described as morphologically and molecularly ordered aggregates having amyloid properties, as filaments without the cross-β-structure and dye binding specific for amyloid, or as amorphous aggregates with no defined structure and fibrillar morphology.Aims and Methods: Here we have expressed human full-length TDP-43 in neuroblastoma x spinal cord 34 (NSC-34) cells to investigate the morphological, structural, and tinctorial properties of TDP-43 inclusions in situ. We have used last-generation amyloid diagnostic probes able to cross the cell membrane and detect amyloid in the cytoplasm and have adopted Raman and Fourier transform infrared microspectroscopies to study in situ the secondary structure of the TDP-43 protein in the inclusions. We have then used transmission electron microscopy to study the morphology of the TDP-43 inclusions.Results: The results show the absence of amyloid dye binding, the lack of an enrichment of cross-β structure in the inclusions, and of a fibrillar texture in the round inclusions. The aggregates formed in vitro from the purified protein under conditions in which it is initially native also lack all these characteristics, ruling out a clear amyloid-like signature.Conclusions: These findings indicate a low propensity of TDP-43 to form amyloid fibrils and even non-amyloid filaments, under conditions in which the protein is initially native and undergoes its typical nucleus-to-cell mislocalization. It cannot be excluded that filaments emerge on the long time scale from such inclusions, but the high propensity of the protein to form initially other types of inclusions appear to be an essential characteristic of TDP-43 proteinopathies.KEY MESSAGESCytoplasmic inclusions of TDP-43 formed in NSC-34 cells do not stain with amyloid-diagnostic dyes, are not enriched with cross-β structure, and do not show a fibrillar morphology.TDP-43 assemblies formed in vitro from pure TDP-43 do not have any hallmarks of amyloid.
Collapse
Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Martina Banchelli
- Institute of Applied Physics "Nello Carrara", National Research Council, Sesto Fiorentino, Italy
| | | | - Diletta Ami
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy.,Milan Center of Neuroscience (NeuroMI), Milan, Italy
| | - Maria Cristina Gagliani
- Cellular Electron Microscopy Laboratory, Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Tommaso Staderini
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Davide Tampellini
- U 1195 INSERM-Université Paris-Saclay, Paris, France.,Institut Professeur Baulieu, Paris, France
| | - Katia Cortese
- Cellular Electron Microscopy Laboratory, Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Antonino Natalello
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy.,Milan Center of Neuroscience (NeuroMI), Milan, Italy
| | - Hadi Adibi
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Paolo Matteini
- Institute of Applied Physics "Nello Carrara", National Research Council, Sesto Fiorentino, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| |
Collapse
|
6
|
Limbocker R, Cremades N, Cascella R, Tessier PM, Vendruscolo M, Chiti F. Characterization of Pairs of Toxic and Nontoxic Misfolded Protein Oligomers Elucidates the Structural Determinants of Oligomer Toxicity in Protein Misfolding Diseases. Acc Chem Res 2023. [PMID: 37071750 DOI: 10.1021/acs.accounts.3c00045] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
ConspectusThe aberrant misfolding and aggregation of peptides and proteins into amyloid aggregates occurs in over 50 largely incurable protein misfolding diseases. These pathologies include Alzheimer's and Parkinson's diseases, which are global medical emergencies owing to their prevalence in increasingly aging populations worldwide. Although the presence of mature amyloid aggregates is a hallmark of such neurodegenerative diseases, misfolded protein oligomers are increasingly recognized as of central importance in the pathogenesis of many of these maladies. These oligomers are small, diffusible species that can form as intermediates in the amyloid fibril formation process or be released by mature fibrils after they are formed. They have been closely associated with the induction of neuronal dysfunction and cell death. It has proven rather challenging to study these oligomeric species because of their short lifetimes, low concentrations, extensive structural heterogeneity, and challenges associated with producing stable, homogeneous, and reproducible populations. Despite these difficulties, investigators have developed protocols to produce kinetically, chemically, or structurally stabilized homogeneous populations of protein misfolded oligomers from several amyloidogenic peptides and proteins at experimentally ameneable concentrations. Furthermore, procedures have been established to produce morphologically similar but structurally distinct oligomers from the same protein sequence that are either toxic or nontoxic to cells. These tools offer unique opportunities to identify and investigate the structural determinants of oligomer toxicity by a close comparative inspection of their structures and the mechanisms of action through which they cause cell dysfunction.This Account reviews multidisciplinary results, including from our own groups, obtained by combining chemistry, physics, biochemistry, cell biology, and animal models for pairs of toxic and nontoxic oligomers. We describe oligomers comprised of the amyloid-β peptide, which underlie Alzheimer's disease, and α-synuclein, which are associated with Parkinson's disease and other related neurodegenerative pathologies, collectively known as synucleinopathies. Furthermore, we also discuss oligomers formed by the 91-residue N-terminal domain of [NiFe]-hydrogenase maturation factor from E. coli, which we use as a model non-disease-related protein, and by an amyloid stretch of Sup35 prion protein from yeast. These oligomeric pairs have become highly useful experimental tools for studying the molecular determinants of toxicity characteristic of protein misfolding diseases. Key properties have been identified that differentiate toxic from nontoxic oligomers in their ability to induce cellular dysfunction. These characteristics include solvent-exposed hydrophobic regions, interactions with membranes, insertion into lipid bilayers, and disruption of plasma membrane integrity. By using these properties, it has been possible to rationalize in model systems the responses to pairs of toxic and nontoxic oligomers. Collectively, these studies provide guidance for the development of efficacious therapeutic strategies to target rationally the cytotoxicity of misfolded protein oligomers in neurodegenerative conditions.
Collapse
Affiliation(s)
- Ryan Limbocker
- Department of Chemistry and Life Science, United States Military Academy, West Point, New York 10996, United States
| | - Nunilo Cremades
- Institute for Biocomputation and Physics of Complex Systems (BIFI) and Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza 50009, Spain
| | - Roberta Cascella
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence 50134, Italy
| | - Peter M Tessier
- Departments of Chemical Engineering, Pharmaceutical Sciences, and Biomedical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Fabrizio Chiti
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence 50134, Italy
| |
Collapse
|
7
|
Bigi A, Cascella R, Fani G, Bernacchioni C, Cencetti F, Bruni P, Chiti F, Donati C, Cecchi C. Sphingosine 1-phosphate attenuates neuronal dysfunction induced by amyloid-β oligomers through endocytic internalization of NMDA receptors. FEBS J 2023; 290:112-133. [PMID: 35851748 PMCID: PMC10087929 DOI: 10.1111/febs.16579] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/24/2022] [Accepted: 07/18/2022] [Indexed: 01/14/2023]
Abstract
Soluble oligomers arising from the aggregation of the amyloid beta peptide (Aβ) have been identified as the main pathogenic agents in Alzheimer's disease (AD). Prefibrillar oligomers of the 42-residue form of Aβ (Aβ42 O) show membrane-binding capacity and trigger the disruption of Ca2+ homeostasis, a causative event in neuron degeneration. Since bioactive lipids have been recently proposed as potent protective agents against Aβ toxicity, we investigated the involvement of sphingosine 1-phosphate (S1P) signalling pathway in Ca2+ homeostasis in living neurons exposed to Aβ42 O. We show that both exogenous and endogenous S1P rescued neuronal Ca2+ dyshomeostasis induced by toxic Aβ42 O in primary rat cortical neurons and human neuroblastoma SH-SY5Y cells. Further analysis revealed a strong neuroprotective effect of S1P1 and S1P4 receptors, and to a lower extent of S1P3 and S1P5 receptors, which activate the Gi -dependent signalling pathways, thus resulting in the endocytic internalization of the extrasynaptic GluN2B-containing N-methyl-D-aspartate receptors (NMDARs). Notably, the S1P beneficial effect can be sustained over time by sphingosine kinase-1 overexpression, thus counteracting the down-regulation of the S1P signalling induced by Aβ42 O. Our findings disclose underlying mechanisms of S1P neuronal protection against harmful Aβ42 O, suggesting that S1P and its signalling axis can be considered promising targets for therapeutic approaches for AD.
Collapse
Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Caterina Bernacchioni
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Francesca Cencetti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Paola Bruni
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Chiara Donati
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
| |
Collapse
|
8
|
Bigi A, Cascella R, Chiti F, Cecchi C. Amyloid fibrils act as a reservoir of soluble oligomers, the main culprits in protein deposition diseases. Bioessays 2022; 44:e2200086. [DOI: 10.1002/bies.202200086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/25/2021] [Accepted: 08/30/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences Section of Biochemistry University of Florence Florence Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences Section of Biochemistry University of Florence Florence Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences Section of Biochemistry University of Florence Florence Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences Section of Biochemistry University of Florence Florence Italy
| |
Collapse
|
9
|
Exploring the Release of Toxic Oligomers from α-Synuclein Fibrils with Antibodies and STED Microscopy. Life (Basel) 2021; 11:life11050431. [PMID: 34064766 PMCID: PMC8150853 DOI: 10.3390/life11050431] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 12/21/2022] Open
Abstract
α-Synuclein (αS) is an intrinsically disordered and highly dynamic protein involved in dopamine release at presynaptic terminals. The abnormal aggregation of αS as mature fibrils into intraneuronal inclusion bodies is directly linked to Parkinson’s disease. Increasing experimental evidence suggests that soluble oligomers formed early during the aggregation process are the most cytotoxic forms of αS. This study investigated the uptake by neuronal cells of pathologically relevant αS oligomers and fibrils exploiting a range of conformation-sensitive antibodies, and the super-resolution stimulated emission depletion (STED) microscopy. We found that prefibrillar oligomers promptly penetrate neuronal membranes, thus resulting in cell dysfunction. By contrast, fibril docking to the phospholipid bilayer is accompanied by αS conformational changes with a progressive release of A11-reactive oligomers, which can enter into the neurons and trigger cell impairment. Our data provide important evidence on the role of αS fibrils as a source of harmful oligomers, which resemble the intermediate conformers formed de novo during aggregation, underling the dynamic and reversible nature of protein aggregates responsible for α-synucleinopathies.
Collapse
|
10
|
Cascella R, Cecchi C. Calcium Dyshomeostasis in Alzheimer's Disease Pathogenesis. Int J Mol Sci 2021; 22:ijms22094914. [PMID: 34066371 PMCID: PMC8124842 DOI: 10.3390/ijms22094914] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 01/12/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder that is characterized by amyloid β-protein deposition in senile plaques, neurofibrillary tangles consisting of abnormally phosphorylated tau protein, and neuronal loss leading to cognitive decline and dementia. Despite extensive research, the exact mechanisms underlying AD remain unknown and effective treatment is not available. Many hypotheses have been proposed to explain AD pathophysiology; however, there is general consensus that the abnormal aggregation of the amyloid β peptide (Aβ) is the initial event triggering a pathogenic cascade of degenerating events in cholinergic neurons. The dysregulation of calcium homeostasis has been studied considerably to clarify the mechanisms of neurodegeneration induced by Aβ. Intracellular calcium acts as a second messenger and plays a key role in the regulation of neuronal functions, such as neural growth and differentiation, action potential, and synaptic plasticity. The calcium hypothesis of AD posits that activation of the amyloidogenic pathway affects neuronal Ca2+ homeostasis and the mechanisms responsible for learning and memory. Aβ can disrupt Ca2+ signaling through several mechanisms, by increasing the influx of Ca2+ from the extracellular space and by activating its release from intracellular stores. Here, we review the different molecular mechanisms and receptors involved in calcium dysregulation in AD and possible therapeutic strategies for improving the treatment.
Collapse
|
11
|
Cascella R, Chen SW, Bigi A, Camino JD, Xu CK, Dobson CM, Chiti F, Cremades N, Cecchi C. The release of toxic oligomers from α-synuclein fibrils induces dysfunction in neuronal cells. Nat Commun 2021; 12:1814. [PMID: 33753734 PMCID: PMC7985515 DOI: 10.1038/s41467-021-21937-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
The self-assembly of α-synuclein (αS) into intraneuronal inclusion bodies is a key characteristic of Parkinson's disease. To define the nature of the species giving rise to neuronal damage, we have investigated the mechanism of action of the main αS populations that have been observed to form progressively during fibril growth. The αS fibrils release soluble prefibrillar oligomeric species with cross-β structure and solvent-exposed hydrophobic clusters. αS prefibrillar oligomers are efficient in crossing and permeabilize neuronal membranes, causing cellular insults. Short fibrils are more neurotoxic than long fibrils due to the higher proportion of fibrillar ends, resulting in a rapid release of oligomers. The kinetics of released αS oligomers match the observed kinetics of toxicity in cellular systems. In addition to previous evidence that αS fibrils can spread in different brain areas, our in vitro results reveal that αS fibrils can also release oligomeric species responsible for an immediate dysfunction of the neurons in the vicinity of these species.
Collapse
Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - Serene W Chen
- Department of Life Science, Imperial College London, London, UK
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - José D Camino
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit BIFI-Institute of Physical Chemistry "Rocasolano" (CSIC), University of Zaragoza, Zaragoza, Spain
| | - Catherine K Xu
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
| | - Nunilo Cremades
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit BIFI-Institute of Physical Chemistry "Rocasolano" (CSIC), University of Zaragoza, Zaragoza, Spain.
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy.
| |
Collapse
|