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Chen SW, 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 DOI: 10.1021/jacs.3c14703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [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.
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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
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2
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Bigi A, Fani G, Bessi V, Napolitano L, Bagnoli S, Ingannato A, Neri L, Cascella R, Matteini P, Sorbi S, Nacmias B, Cecchi C, Chiti F. Putative novel CSF biomarkers of Alzheimer's disease based on the novel concept of generic protein misfolding and proteotoxicity: the PRAMA cohort. Transl Neurodegener 2024; 13:14. [PMID: 38459525 PMCID: PMC10924410 DOI: 10.1186/s40035-024-00405-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 02/16/2024] [Indexed: 03/10/2024] Open
Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy
| | - Valentina Bessi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliero-Universitaria Careggi. Largo Brambilla, 3, 50134, Florence, Italy
| | - Liliana Napolitano
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy
| | - Silvia Bagnoli
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliero-Universitaria Careggi. Largo Brambilla, 3, 50134, Florence, Italy
| | - Assunta Ingannato
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliero-Universitaria Careggi. Largo Brambilla, 3, 50134, Florence, Italy
| | - Lorenzo Neri
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy
| | - Paolo Matteini
- Institute of Applied Physics "Nello Carrara", National Research Council, 50019, Sesto Fiorentino, Italy
| | - Sandro Sorbi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliero-Universitaria Careggi. Largo Brambilla, 3, 50134, Florence, Italy
- IRCCS Fondazione Don Carlo Gnocchi, Florence, Italy
| | - Benedetta Nacmias
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliero-Universitaria Careggi. Largo Brambilla, 3, 50134, Florence, Italy
- IRCCS Fondazione Don Carlo Gnocchi, Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy.
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Section of Biochemistry, University of Florence, Viale Morgagni 50, 50134, Florence, Italy.
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3
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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.
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4
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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5
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Abstract
The misfolding and aggregation of α-synuclein is the general hallmark of a group of devastating neurodegenerative pathologies referred to as synucleinopathies, such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. In such conditions, a range of different misfolded aggregates, including oligomers, protofibrils, and fibrils, are present both in neurons and glial cells. Growing experimental evidence supports the proposition that soluble oligomeric assemblies, formed during the early phases of the aggregation process, are the major culprits of neuronal toxicity; at the same time, fibrillar conformers appear to be the most efficient at propagating among interconnected neurons, thus contributing to the spreading of α-synuclein pathology. Moreover, α-synuclein fibrils have been recently reported to release soluble and highly toxic oligomeric species, responsible for an immediate dysfunction in the recipient neurons. In this review, we discuss the current knowledge about the plethora of mechanisms of cellular dysfunction caused by α-synuclein oligomers and fibrils, both contributing to neurodegeneration in synucleinopathies.
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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
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence, Italy
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6
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Capitini C, Bigi A, Parenti N, Emanuele M, Bianchi N, Cascella R, Cecchi C, Maggi L, Annunziato F, Pavone FS, Calamai M. APP and Bace1: Differential effect of cholesterol enrichment on processing and plasma membrane mobility. iScience 2023; 26:106611. [PMID: 37128606 PMCID: PMC10148118 DOI: 10.1016/j.isci.2023.106611] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/08/2023] [Accepted: 03/31/2023] [Indexed: 05/03/2023] Open
Abstract
High cholesterol levels are a risk factor for the development of Alzheimer's disease. Experiments investigating the influence of cholesterol on the proteolytic processing of the amyloid precursor protein (APP) by the β-secretase Bace1 and on their proximity in cells have led to conflicting results. By using a fluorescence bioassay coupled with flow cytometry we found a direct correlation between the increase in membrane cholesterol amount and the degree of APP shedding in living human neuroblastoma cells. Analogue results were obtained for cells overexpressing an APP mutant that cannot be processed by α-secretase, highlighting the major influence of cholesterol enrichment on the cleavage of APP carried out by Bace1. By contrast, the cholesterol content was not correlated with changes in membrane dynamics of APP and Bace1 analyzed with single molecule tracking, indicating that the effect of cholesterol enrichment on APP processing by Bace1 is uncoupled from changes in their lateral diffusion.
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Affiliation(s)
- Claudia Capitini
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, 50019 Florence, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Niccolò Parenti
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019Florence, Italy
| | - Marco Emanuele
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019Florence, Italy
| | - Niccolò Bianchi
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Laura Maggi
- Department of Experimental and Clinical Medicine, University of Florence 50134 Florence, Italy
| | - Francesco Annunziato
- Department of Experimental and Clinical Medicine, University of Florence 50134 Florence, Italy
| | - Francesco Saverio Pavone
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, 50019 Florence, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019Florence, Italy
- National Institute of Optics, National Research Council of Italy (CNR), Largo Fermi 6, 50125Florence, Italy
| | - Martino Calamai
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019Florence, Italy
- National Institute of Optics, National Research Council of Italy (CNR), Largo Fermi 6, 50125Florence, Italy
- Corresponding author
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7
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Bigi A, Lombardo E, Cascella R, Cecchi C. The Toxicity of Protein Aggregates: New Insights into the Mechanisms. Int J Mol Sci 2023; 24:ijms24097974. [PMID: 37175681 PMCID: PMC10178715 DOI: 10.3390/ijms24097974] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
The aberrant aggregation of specific peptides and proteins is the common feature of a range of more than 50 human pathologies, collectively referred to as protein misfolding diseases [...].
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Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Eva Lombardo
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
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8
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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: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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9
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Staderini T, Bigi A, Mongiello D, Cecchi C, Chiti F. Biophysical characterization of full-length TAR DNA-binding protein (TDP-43) phase separation. Protein Sci 2022; 31:e4509. [PMID: 36371546 PMCID: PMC9703588 DOI: 10.1002/pro.4509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/17/2022] [Accepted: 11/05/2022] [Indexed: 11/15/2022]
Abstract
Amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions are associated with deposition of cytosolic inclusion bodies of TAR DNA-binding protein 43 (TDP-43) in brain and motor neurons. We induced phase separation of purified full-length TDP-43 devoid of large tags using a solution-jump method, and monitored it with an array of biophysical techniques. The tetramethylrhodamine-5-maleimide- or Alexa488-labeled protein formed rapidly (<1 min) apparently round, homogeneous and 0.5-1.0 μm wide assemblies, when imaged using confocal fluorescence, bright-field, and stimulated emission depletion microscopy. The assemblies, however, had limited internal diffusion, as assessed with fluorescence recovery after photobleaching, and did not coalesce, but rather clustered into irregular bunches, unlike those formed by the C-terminal domain. They were enriched with α-helical structure, with minor contributions of β-sheet/random structure, had a red-shifted tryptophan fluorescence and did not bind thioflavin T. By monitoring with turbidimetry both the formation of the spherical species and their further clustering under different experimental conditions, we carried out a multiparametric analysis of the two phenomena. In particular, both processes were found to be promoted by high protein concentrations, salts, crowding agents, weakly by reducing agents, as the pH approached a value of 6.0 from either side (corresponding to the TDP-43 isoionic point), and as the temperature approached a value of 31°C from either side. Important differences were found with respect to the TDP-43 C-terminal domain. Our multiparametric results also provide explanations to some of the solubility data obtained on full-length TDP-43 that were difficult to explain following the multiparametric analysis acquired on the C-terminal domain.
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Affiliation(s)
- Tommaso Staderini
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Daniele Mongiello
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”University of FlorenceFlorenceItaly
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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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
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11
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Cascella R, Bigi A, Riffert DG, Gagliani MC, Ermini E, Moretti M, Cortese K, Cecchi C, Chiti F. A quantitative biology approach correlates neuronal toxicity with the largest inclusions of TDP-43. Sci Adv 2022; 8:eabm6376. [PMID: 35895809 PMCID: PMC9328675 DOI: 10.1126/sciadv.abm6376] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A number of neurodegenerative conditions are associated with the formation of cytosolic inclusions of TDP-43 within neurons. We expressed full-length TDP-43 in a motoneuron/neuroblastoma hybrid cell line (NSC-34) and exploited the high-resolution power of stimulated emission depletion microscopy to monitor the changes of nuclear and cytoplasmic TDP-43 levels and the formation of various size classes of cytoplasmic TDP-43 aggregates with time. Concomitantly, we monitored oxidative stress and mitochondrial impairment using the MitoSOX and MTT reduction assays, respectively. Using a quantitative biology approach, we attributed neuronal dysfunction associated with cytoplasmic deposition component to the formation of the largest inclusions, independently of stress granules. This is in contrast to other neurodegenerative diseases where toxicity is attributed to small oligomers. Using specific inhibitors, markers, and electron microscopy, the proteasome and autophagy were found to target mainly the largest deleterious inclusions, but their efficiency soon decreases without full recovery of neuronal viability.
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Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Dylan Giorgino Riffert
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Maria Cristina Gagliani
- Department of Experimental Medicine, Cellular Electron Microscopy Laboratory, University of Genova, 16132 Genova, Italy
| | - Emilio Ermini
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Matteo Moretti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
| | - Katia Cortese
- Department of Experimental Medicine, Cellular Electron Microscopy Laboratory, University of Genova, 16132 Genova, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
- Corresponding author. (C.C.); (F.C.)
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy
- Corresponding author. (C.C.); (F.C.)
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12
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Limbocker R, Staats R, Chia S, Ruggeri FS, Mannini B, Xu CK, Perni M, Cascella R, Bigi A, Sasser LR, Block NR, Wright AK, Kreiser RP, Custy ET, Meisl G, Errico S, Habchi J, Flagmeier P, Kartanas T, Hollows JE, Nguyen LT, LeForte K, Barbut D, Kumita JR, Cecchi C, Zasloff M, Knowles TPJ, Dobson CM, Chiti F, Vendruscolo M. Squalamine and Its Derivatives Modulate the Aggregation of Amyloid-β and α-Synuclein and Suppress the Toxicity of Their Oligomers. Front Neurosci 2021; 15:680026. [PMID: 34220435 PMCID: PMC8249941 DOI: 10.3389/fnins.2021.680026] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022] Open
Abstract
The aberrant aggregation of proteins is a key molecular event in the development and progression of a wide range of neurodegenerative disorders. We have shown previously that squalamine and trodusquemine, two natural products in the aminosterol class, can modulate the aggregation of the amyloid-β peptide (Aβ) and of α-synuclein (αS), which are associated with Alzheimer's and Parkinson's diseases. In this work, we expand our previous analyses to two squalamine derivatives, des-squalamine and α-squalamine, obtaining further insights into the mechanism by which aminosterols modulate Aβ and αS aggregation. We then characterize the ability of these small molecules to alter the physicochemical properties of stabilized oligomeric species in vitro and to suppress the toxicity of these aggregates to varying degrees toward human neuroblastoma cells. We found that, despite the fact that these aminosterols exert opposing effects on Aβ and αS aggregation under the conditions that we tested, the modifications that they induced to the toxicity of oligomers were similar. Our results indicate that the suppression of toxicity is mediated by the displacement of toxic oligomeric species from cellular membranes by the aminosterols. This study, thus, provides evidence that aminosterols could be rationally optimized in drug discovery programs to target oligomer toxicity in Alzheimer's and Parkinson's diseases.
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Affiliation(s)
- Ryan Limbocker
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Roxine Staats
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Sean Chia
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Francesco S. Ruggeri
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Laboratory of Organic Chemistry, Wageningen University, Wageningen, Netherlands
- Laboratory of Physical Chemistry, Wageningen University, Wageningen, Netherlands
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Catherine K. Xu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Michele Perni
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Liam R. Sasser
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Natalie R. Block
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Aidan K. Wright
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Ryan P. Kreiser
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Edward T. Custy
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Georg Meisl
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Silvia Errico
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Johnny Habchi
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Patrick Flagmeier
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Tadas Kartanas
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jared E. Hollows
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Lam T. Nguyen
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | - Kathleen LeForte
- Department of Chemistry & Life Science, United States Military Academy, West Point, NY, United States
| | | | - Janet R. Kumita
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Michael Zasloff
- Enterin Inc., Philadelphia, PA, United States
- MedStar Georgetown Transplant Institute, School of Medicine, Georgetown University, Washington, DC, United States
| | - Tuomas P. J. Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M. Dobson
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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13
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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: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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.
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14
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Bigi A, Loffredo G, Cascella R, Cecchi C. Targeting Pathological Amyloid Aggregates with Conformation-Sensitive Antibodies. Curr Alzheimer Res 2020; 17:722-734. [PMID: 33167834 DOI: 10.2174/1567205017666201109093848] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 08/05/2020] [Accepted: 10/01/2020] [Indexed: 01/10/2023]
Abstract
BACKGROUND The pathogenesis of Alzheimer's disease (AD) is not directly caused by the presence of senile plaques but rather by the detrimental effects exerted on neuronal cells by toxic soluble oligomers. Such species are formed early during the aggregation process of the Aβ1-42 peptide or can be released from mature fibrils. Nowadays, efficient tools for an early diagnosis, as well as pharmaceutical treatments targeting the harmful agents in samples of AD patients, are still missing. OBJECTIVE By integrating in vitro immunochemical assay with in vivo neuronal models of toxicity, we aim to understand and target the principles that drive toxicity in AD. METHODS We evaluated the specificity and sensitivity of A11 and OC conformational antibodies to target a range of pathologically relevant amyloid conformers and rescue their cytotoxic effects in neuronal culture models using a number of cellular readouts. RESULTS We demonstrated the peculiar ability of conformational antibodies to label pathologically relevant Aβ1-42 oligomers and fibrils and to prevent their detrimental effects on neuronal cells. CONCLUSION Our results substantially improve our knowledge on the role of toxic assemblies in neurodegenerative diseases, thus suggesting new and more effective diagnostic and therapeutic tools for AD.
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Affiliation(s)
- Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence 50134, Italy
| | - Gilda Loffredo
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Florence 50134, Italy
| | - Roberta Cascella
- 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
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15
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Limbocker R, Mannini B, Ruggeri FS, Cascella R, Xu CK, Perni M, Chia S, Chen SW, Habchi J, Bigi A, Kreiser RP, Wright AK, Albright JA, Kartanas T, Kumita JR, Cremades N, Zasloff M, Cecchi C, Knowles TPJ, Chiti F, Vendruscolo M, Dobson CM. Trodusquemine displaces protein misfolded oligomers from cell membranes and abrogates their cytotoxicity through a generic mechanism. Commun Biol 2020; 3:435. [PMID: 32792544 PMCID: PMC7426408 DOI: 10.1038/s42003-020-01140-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/07/2020] [Indexed: 12/21/2022] Open
Abstract
The onset and progression of numerous protein misfolding diseases are associated with the presence of oligomers formed during the aberrant aggregation of several different proteins, including amyloid-β (Aβ) in Alzheimer’s disease and α-synuclein (αS) in Parkinson’s disease. These small, soluble aggregates are currently major targets for drug discovery. In this study, we show that trodusquemine, a naturally-occurring aminosterol, markedly reduces the cytotoxicity of αS, Aβ and HypF-N oligomers to human neuroblastoma cells by displacing the oligomers from cell membranes in the absence of any substantial morphological and structural changes to the oligomers. These results indicate that the reduced toxicity results from a mechanism that is common to oligomers from different proteins, shed light on the origin of the toxicity of the most deleterious species associated with protein aggregation and suggest that aminosterols have the therapeutically-relevant potential to protect cells from the oligomer-induced cytotoxicity associated with numerous protein misfolding diseases. Limbocker et al. show that trodusquemine, an aminosterol, reduces the cytotoxicity of protein misfolded oligomers by displacing them from cell membranes in the absence of any overt structural/ morphological changes in them. This mechanism appears to be general, as they test it for oligomers of αS, Aβ and the model protein HypF-N to human neuroblastoma cells.
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Affiliation(s)
- Ryan Limbocker
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Francesco S Ruggeri
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy
| | - Catherine K Xu
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Michele Perni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Sean Chia
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Serene W Chen
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Johnny Habchi
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy
| | - Ryan P Kreiser
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Aidan K Wright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - J Alex Albright
- Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Tadas Kartanas
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Janet R Kumita
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Nunilo Cremades
- Institute for Biocomputation and Physics of Complex Systems (BIFI)-Joint Unit BIFI-IQFR (CSIC), University of Zaragoza, 50018, Zaragoza, Spain
| | - Michael Zasloff
- MedStar-Georgetown Transplant Institute, Georgetown University School of Medicine, Washington, DC, 20010, USA
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Science, University of Florence, 50134, Florence, Italy.
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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16
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La Manna S, Scognamiglio PL, Roviello V, Borbone F, Florio D, Di Natale C, Bigi A, Cecchi C, Cascella R, Giannini C, Sibillano T, Novellino E, Marasco D. The acute myeloid leukemia-associated Nucleophosmin 1 gene mutations dictate amyloidogenicity of the C-terminal domain. FEBS J 2019; 286:2311-2328. [PMID: 30921500 DOI: 10.1111/febs.14815] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/29/2019] [Accepted: 03/21/2019] [Indexed: 01/04/2023]
Abstract
Nucleophosmin 1 (NPM1) is a nucleus-cytoplasm shuttling protein ubiquitously expressed and highly conserved. It is involved in many cellular processes and its gene is mutated in ~ 50-60% of Acute Myeloid Leukemia (AML) patients. These mutations cause its cytoplasmic mislocation and accumulation (referred to as NPM1c+) and open the door to rational targeted therapy for AML diseases with mutated NPM1. Currently, there is limited knowledge on the mechanism of action of NPM1c+ and on structural determinants of the leukemogenic potential of AML mutations. Numerous previous studies outlined an unexpected amyloid-like aggregation tendency of several regions located in the C-terminal domain that, in wild-type form, fold as a three-helical-bundle. Here, using a combination of different techniques including Thioflavin T fluorescence, congo red absorbance, CD spectroscopy, Scanning Electron Microscopy (SEM) and wide-angle X-ray scattering on a series of peptides bearing mutations, we evidence that the amyloidogenicity of NPM1 mutants is directly linked to AML. Noticeably, AML point mutations strongly affect the amyloid cytotoxic effects in neuroblastoma cells and the morphologies of deriving fibrils. This study paves the way to deepen our understanding of AML-associated NPM1 mutants, and could help to break new ground for the identification of novel drugs targeting NPM1c+ for treatment of AML.
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Affiliation(s)
- Sara La Manna
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", Italy
| | - Pasqualina Liana Scognamiglio
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", Italy
| | - Valentina Roviello
- Analytical Chemistry for the Environment and CeSMA (Advanced Metrologic Service Center), University of Naples "Federico II", Italy
| | - Fabio Borbone
- Department of Chemical Sciences, University of Naples "Federico II", Italy
| | - Daniele Florio
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", Italy
| | - Concetta Di Natale
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, Italy
| | - Cinzia Giannini
- Institute of Crystallography (IC), National Research Council, Bari, Italy
| | - Teresa Sibillano
- Institute of Crystallography (IC), National Research Council, Bari, Italy
| | - Ettore Novellino
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", Italy
| | - Daniela Marasco
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", Italy
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17
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Cascella R, Evangelisti E, Bigi A, Becatti M, Fiorillo C, Stefani M, Chiti F, Cecchi C. Soluble Oligomers Require a Ganglioside to Trigger Neuronal Calcium Overload. J Alzheimers Dis 2018; 60:923-938. [PMID: 28922156 DOI: 10.3233/jad-170340] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An altered distribution of membrane gangliosides (GM), including GM1, has recently been reported in the brains of Alzheimer's disease (AD) patients. Moreover, amyloid-positive synaptosomes obtained from AD brains were found to contain high-density GM1 clusters, suggesting a pathological significance of GM1 increase at presynaptic neuritic terminals in AD. Here, we show that membrane GM1 specifically recruits small soluble oligomers of the 42-residue form of amyloid-β peptide (Aβ42), with intracellular flux of Ca2+ ions in primary rat hippocampal neurons and in human neuroblastoma cells. Specific membrane proteins appear to be involved in the early and transient influx of Ca2+ ions induced by Aβ42 oligomers with high solvent-exposed hydrophobicity (A+), but not in the sustained late influx of the same oligomers and in that induced by Aβ42 oligomers with low solvent-exposed hydrophobicity (A-) in GM1-enriched cells. In addition, A+ oligomers accumulate in proximity of membrane NMDA and AMPA receptors, inducing the early and transient Ca2+ influx, although FRET shows that the interaction is not direct. These results suggest that age-dependent clustering of GM1 within neuronal membranes could induce neurodegeneration in elderly people as a consequence of an increased ability of the lipid bilayers to recruit membrane-permeabilizing oligomers. We also show that both lipid and protein components of the plasma membrane can contribute to neuronal dysfunction, thus expanding the molecular targets for therapeutic intervention in AD.
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Affiliation(s)
- Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Elisa Evangelisti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Alessandra Bigi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Matteo Becatti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Claudia Fiorillo
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
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18
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Bernardoni V, Elser M, Valli G, Valentini S, Bigi A, Fermo P, Piazzalunga A, Vecchi R. Size-segregated aerosol in a hot-spot pollution urban area: Chemical composition and three-way source apportionment. Environ Pollut 2017; 231:601-611. [PMID: 28843899 DOI: 10.1016/j.envpol.2017.08.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/10/2017] [Accepted: 08/11/2017] [Indexed: 06/07/2023]
Abstract
In this work, a comprehensive characterisation and source apportionment of size-segregated aerosol collected using a multistage cascade impactor was performed. The samples were collected during wintertime in Milan (Italy), which is located in the Po Valley, one of the main pollution hot-spot areas in Europe. For every sampling, size-segregated mass concentration, elemental and ionic composition, and levoglucosan concentration were determined. Size-segregated data were inverted using the program MICRON to identify and quantify modal contributions of all the measured components. The detailed chemical characterisation allowed the application of a three-way (3-D) receptor model (implemented using Multilinear Engine) for size-segregated source apportionment and chemical profiles identification. It is noteworthy that - as far as we know - this is the first time that three-way source apportionment is attempted using data of aerosol collected by traditional cascade impactors. Seven factors were identified: wood burning, industry, resuspended dust, regional aerosol, construction works, traffic 1, and traffic 2. Further insights into size-segregated factor profiles suggested that the traffic 1 factor can be associated to diesel vehicles and traffic 2 to gasoline vehicles. The regional aerosol factor resulted to be the main contributor (nearly 50%) to the droplet mode (accumulation sub-mode with modal diameter in the range 0.5-1 μm), whereas the overall contribution from the two factors related to traffic was the most important one in the other size modes (34-41%). The results showed that applying a 3-D receptor model to size-segregated samples allows identifying factors of local and regional origin while receptor modelling on integrated PM fractions usually singles out factors characterised by primary (e.g. industry, traffic, soil dust) and secondary (e.g. ammonium sulphate and nitrate) origin. Furthermore, the results suggested that the information on size-segregated chemical composition in different size classes was exploited by the model to relate primary emissions to rapidly-formed secondary compounds.
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Affiliation(s)
- V Bernardoni
- Dipartimento di Fisica, Università Degli Studi di Milano and INFN-Milan, Milan, Italy
| | - M Elser
- Dipartimento di Fisica, Università Degli Studi di Milano and INFN-Milan, Milan, Italy
| | - G Valli
- Dipartimento di Fisica, Università Degli Studi di Milano and INFN-Milan, Milan, Italy
| | - S Valentini
- Dipartimento di Fisica, Università Degli Studi di Milano and INFN-Milan, Milan, Italy
| | - A Bigi
- Dipartimento di Ingegneria "Enzo Ferrari", Università Degli Studi di Modena e Reggio Emilia, Modena, Italy
| | - P Fermo
- Dipartimento di Chimica, Università Degli Studi di Milano, Milan, Italy
| | - A Piazzalunga
- Dipartimento di Chimica, Università Degli Studi di Milano, Milan, Italy
| | - R Vecchi
- Dipartimento di Fisica, Università Degli Studi di Milano and INFN-Milan, Milan, Italy.
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19
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Bigi A, Beltrami E, Trinei M, Stendardo M, Pelicci PG, Giorgio M. Cyclophilin D counteracts P53-mediated growth arrest and promotes Ras tumorigenesis. Oncogene 2016; 35:5132-43. [PMID: 26973251 DOI: 10.1038/onc.2016.42] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 01/04/2016] [Accepted: 02/08/2016] [Indexed: 02/07/2023]
Abstract
Mitochondrial alterations induced by oncogenes are known to be crucial for tumorigenesis. Ras oncogene leads to proliferative signals through a Raf-1/MEK/ERK kinase cascade, whose components have been found to be also associated with mitochondria. The mitochondrial pepdidyl-prolyl isomerase cyclophilin D (CypD) is an important regulator of the mitochondrial permeability transition and a key player in mitochondria physiology; however, its role in cancer is still unclear. Using cellular and in vivo mouse models, we demonstrated that CypD protein upregulation induced by oncogenic Ras through the Raf-1/MEK/ERK pathway has a deterministic role in tumor progression. In fact, targeting CypD gene expression clearly affected RasV12-induced transformation, as showed by in vitro data on murine NIH3T3 and human MCF10A mammary epithelial cells. In addition, studies in xenograft and K-Ras lung cancer mouse models demonstrated that genetic deletion or pharmacological suppression of CypD efficiently prevented Ras-dependent tumor formation. Furthermore, Erbb2-mediated breast tumorigenesis was similarly prevented by targeting CypD. From a mechanistic point of view, CypD expression was associated with a reduced induction of p21(WAF1/CIP1) and p53 functions, unraveling an antagonistic function of CypD on p21-p53-mediated growth suppression. CypD activity is p53 dependent. Interestingly, a physical association between p53 and CypD was detected in mitochondria of MCF10A cells; furthermore, both in vitro and in vivo studies proved that CypD inhibitor-based treatment was able to efficiently impair this interaction, leading to a tumor formation reduction. All together, these findings indicate that the countering effect of CypD on the p53-p21 pathway participates in oncogene-dependent transformation.
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Affiliation(s)
- A Bigi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - E Beltrami
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - M Trinei
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - M Stendardo
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - P G Pelicci
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - M Giorgio
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
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Abstract
INTRODUCTION Tracheal rhinoscleroma is an infectious granulomatosis of the tracheobronchial tract caused by a Gram-negative bacillus. Exclusively tracheal involvement has been rarely reported in the literature. The purpose of this study was to report a case of subglottic stenosis secondary to rhinoscleroma. SUMMARY A 46-year-old North African woman with no medical or surgical history presented with inspiratory dyspnoea that had been present for several years. Endoscopic examination under general anaesthesia revealed tracheal stenosis. Histological examination of mucosal biopsies demonstrated Mikulicz cells and culture of bacteriological samples taken during a second biopsy confirmed the diagnosis of rhinoscleroma. CO2 laser subglottic obstruction relief was performed and treatment with ofloxacin was initiated. No recurrence of tracheal stenosis was observed with a follow-up of 6 months. DISCUSSION The diagnosis of rhinoscleroma is based on histological and bacteriological examination. Cultures are positive in 60% of cases, but negative cultures do not exclude the diagnosis of rhinoscleroma. Specific treatment consists of long-term antibiotic therapy, while surgery may be indicated for symptomatic treatment.
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Affiliation(s)
- A Bigi
- Département de chirurgie cervico-faciale, centre hospitalo universitaire, hôpital Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France.
| | - M Bartolomeo
- Département de chirurgie cervico-faciale, centre hospitalo universitaire, hôpital Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France
| | - V Costes
- Département d'anatomopathologie, pôle neurosciences, centre hospitalo universitaire, hôpital Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France
| | - M Makeieff
- Département de chirurgie cervico-faciale, centre hospitalo universitaire, hôpital Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France
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21
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Rapino S, Marcu R, Bigi A, Soldà A, Marcaccio M, Paolucci F, Pelicci PG, Giorgio M. Scanning electro-chemical microscopy reveals cancer cell redox state. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.04.053] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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22
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Bartolomeo M, Bigi A, Pelliccia P, Makeieff M. Surgical treatment of a case of adult epiglottic laryngomalacia. Eur Ann Otorhinolaryngol Head Neck Dis 2015; 132:45-7. [DOI: 10.1016/j.anorl.2013.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 08/22/2013] [Accepted: 10/30/2013] [Indexed: 11/16/2022]
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23
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Leone G, Volpato MD, Nelli N, Lamponi S, Boanini E, Bigi A, Magnani A. Continuous multilayered composite hydrogel as osteochondral substitute. J Biomed Mater Res A 2014; 103:2521-30. [PMID: 25504681 DOI: 10.1002/jbm.a.35389] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 12/02/2014] [Accepted: 12/08/2014] [Indexed: 01/28/2023]
Abstract
Cartilage is a highly organized avascular soft tissue that assembles from nano-to macro-scale to produce a complex structural network. To mimic cartilage tissue, we developed a stable multilayered composite material, characterized by a tailored gradient of mechanical properties. The optimized procedure implies chemical crosslinking of each layer directly onto the previous one and ensures a drastic reduction of the material discontinuities and brittleness. The multilayered composite was characterized by infrared spectroscopy, differential scanning calorimetry, thermogravimetry, and scanning electron microscopy in order to compare its physico-chemical characteristics with those of cartilage tissue. The rheological behavior of the multilayered composite was similar to that of human cartilage. Finally its cytocompatibility toward chondrocytes and osteoblasts was evaluated.
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Affiliation(s)
- G Leone
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena (INSTM), via Aldo Moro 2, Siena, 53100, Italy
| | - M D Volpato
- Via Fratelli Rosselli, 16-Colle Di Val D'elsa, Siena, Italy
| | - N Nelli
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena (INSTM), via Aldo Moro 2, Siena, 53100, Italy
| | - S Lamponi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena (INSTM), via Aldo Moro 2, Siena, 53100, Italy
| | - E Boanini
- Department of Chemistry "G. Ciamician,", University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - A Bigi
- Department of Chemistry "G. Ciamician,", University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - A Magnani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena (INSTM), via Aldo Moro 2, Siena, 53100, Italy
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24
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Bigi A, Tringali C, Forcella M, Mozzi A, Venerando B, Monti E, Fusi P. A proline-rich loop mediates specific functions of human sialidase NEU4 in SK-N-BE neuronal differentiation. Glycobiology 2013; 23:1499-509. [PMID: 24030392 DOI: 10.1093/glycob/cwt078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human sialidase NEU4 long (N4L) is a membrane-associated enzyme that has been shown to be localized in the outer mitochondrial membrane. A role in different cellular processes has been suggested for this enzyme, such as apoptosis, neuronal differentiation and tumorigenesis. However, the molecular bases for these roles, not found in any of the other highly similar human sialidases, are not understood. We have found that a proline-rich sequence of 81 amino acids, unique to NEU4 sequence, contains potential Akt and Erk1 kinase motifs. Molecular modeling, based on the experimentally determined three-dimensional structure of cytosolic human NEU2, showed that the proline-rich sequence is accommodated in a loop, thus preserving the typical beta-barrel structure of sialidases. In order to investigate the role of this loop in neuronal differentiation, we obtained SK-N-BE neuroblastoma cells stably overexpressing either human wild-type N4L or a deletion mutant lacking the proline-rich loop. Our results demonstrate that the proline-rich region can also enhance cell proliferation and retinoic acid (RA)-induced neuronal differentiation and it is also involved in NEU4 interaction with Akt, as well as in substrate recognition, modifying directly or through the interaction with other protein(s) the enzyme specificity toward sialylated glycoprotein(s). On the whole, our results suggest that N4L could be a downstream component of the PI3K/Akt signaling pathway required for RA-induced differentiation of neuroblastoma SK-N-BE cells.
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Affiliation(s)
- Alessandra Bigi
- Department of Biotechnologies and Biosciences, University of Milan-Bicocca, 20126 Milan, Italy
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25
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Forcella M, Mozzi A, Bigi A, Parenti P, Fusi P. Molecular cloning of soluble trehalase from Chironomus riparius larvae, its heterologous expression in Escherichia coli and bioinformatic analysis. Arch Insect Biochem Physiol 2012; 81:77-89. [PMID: 22851493 DOI: 10.1002/arch.21041] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Trehalase is involved in the control of trehalose concentration, the main blood sugar in insects. Here, we describe the molecular cloning of the cDNA encoding for the soluble form of the trehalase from the midge larvae of Chironomus riparius, a well-known bioindicator of the quality of freshwater environments. Molecular cloning was achieved through multiple alignment of Diptera trehalase sequences, allowing the synthesis of internal homology-based primers; the complete open reading frame(ORF) was subsequently obtained through RACE-PCR(where RACE is rapid amplification of cDNA ends). The cDNA contained the 5' untranslated region (UTR), the 3' UTR including a poly(A) tail and the ORF of 1,725 bp consisting of 574 amino acid residues with a predicted molecular mass of 65,778 Da. Recombinant trehalase was successfully expressed in Escherichia coli as a His-tagged protein and purified on Ni-NTA affinity chromatography. Primary structure analysis showed a series of characteristic features shared by all insect trehalases, while three-dimensional structure prediction yielded the typical glucosidase fold, the two key residues involved in the catalytic mechanism being conserved. Production of recombinant insect trehalases opens the way to structural characterizations of the catalytic site, which might represent, among others, an element for reconsidering the enzyme as a target in pest insects' control.
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Affiliation(s)
- Matilde Forcella
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, Milan, Italy
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26
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Panzavolta S, Bracci B, Focarete ML, Gualandi C, Bigi A. Fiber reinforcement of a biomimetic bone cement. J Mater Sci Mater Med 2012; 23:1363-1370. [PMID: 22528068 DOI: 10.1007/s10856-012-4618-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/08/2012] [Indexed: 05/31/2023]
Abstract
In this study we investigated the influence of electrospun polymer fibers on the properties of a α-tricalcium phosphate/gelatin biomimetic cement. To this aim, we added different amounts of poly(L-lactic acid) and poly(lactide-co-glycolide) fibers to the cement composition. Fibers enrichment provoked a significant reduction of both initial and final setting times. Moreover electrospun polymer fibers slowed down the conversion of α-tricalcium phosphate into calcium deficient hydroxyapatite. As a result, the final cements were more compact than the control cement, because of the smaller crystal dimensions and reduced crystallinity of the apatitic phase. The compressive strength, σ(b), and Young's modulus, E, of the control cement decreased significantly after 40 days soaking in physiological solution, whereas the more compact microstructure enabled fiber reinforced cements to maintain their mechanical properties in the long term.
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Affiliation(s)
- S Panzavolta
- Department of Chemistry G. Ciamician, University of Bologna, Bologna, Italy.
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27
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Bigi A, Bracci B, Cojazzi G, Panzavolta S, Rubini K. In vitro mineralization of gelatin-polyacrylic acid complex matrices. Journal of Biomaterials Science, Polymer Edition 2012; 15:243-54. [PMID: 15147160 DOI: 10.1163/156856204322977166] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Gelatin-polyacrylic acid (gel-PAA) matrices were obtained by slow diffusion of polyacrylic acid into gelatin gels. The matrices were submitted to uniaxial stretching, which induces a preferential orientation of the collagen molecules, and used as biomimetic substrates for the nucleation of hydroxyapatite from simulated body fluid (SBF). The relative amount of hydroxyapatite deposited from 1.5SBF increases as a function of polyelectrolyte content in the matrices, up to about 30 wt%. In the absence of PAA, the inorganic phase is laid down on the surface of the gelatin matrices as hemispherical aggregates. At variance, hydroxyapatite deposition in the gel-PAA composite matrices at relatively low PAA content occurs preferentially in the spaces between the layers on the surface of the matrices and displays a tablet-like morphology. At high polyelectrolyte concentration, an almost uniform layer of hydroxyapatite covers the whole surface of the matrices. The preferential orientation of the (002) hydroxyapatite reflection indicates a close relationship between the inorganic crystals and the collagen molecules.
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Affiliation(s)
- A Bigi
- Department of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, Italy.
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28
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Tripodi F, Pagliarin R, Fumagalli G, Bigi A, Fusi P, Orsini F, Frattini M, Coccetti P. Synthesis and Biological Evaluation of 1,4-Diaryl-2-azetidinones as Specific Anticancer Agents: Activation of Adenosine Monophosphate Activated Protein Kinase and Induction of Apoptosis. J Med Chem 2012; 55:2112-24. [DOI: 10.1021/jm201344a] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Farida Tripodi
- Department of Biotechnology
and Biosciences, University of Milan-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Roberto Pagliarin
- Department of Organic and Industrial
Chemistry, University of Milan, Via Venezian
21, 20133 Milan, Italy
| | - Gabriele Fumagalli
- Department of Organic and Industrial
Chemistry, University of Milan, Via Venezian
21, 20133 Milan, Italy
| | - Alessandra Bigi
- Department of Biotechnology
and Biosciences, University of Milan-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Paola Fusi
- Department of Biotechnology
and Biosciences, University of Milan-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Fulvia Orsini
- Department of Organic and Industrial
Chemistry, University of Milan, Via Venezian
21, 20133 Milan, Italy
| | - Milo Frattini
- Institute of Pathology, Via in Selva 24,
6600 Locarno, Switzerland
| | - Paola Coccetti
- Department of Biotechnology
and Biosciences, University of Milan-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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29
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Boanini E, Torricelli P, Fini M, Bigi A. Osteopenic bone cell response to strontium-substituted hydroxyapatite. J Mater Sci Mater Med 2011; 22:2079-2088. [PMID: 21691830 DOI: 10.1007/s10856-011-4379-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 06/09/2011] [Indexed: 05/30/2023]
Abstract
Ionic substitution is a powerful tool to improve the biological performance of calcium phosphate based materials. In this work, we investigated the response of primary cultures of rat osteoblasts derived from osteopenic (O-OB) bone to strontium substituted hydroxyapatite (SrHA), and to hydroxyapatite (HA) as reference material, compared to normal (N-OB) bone cells. Strontium (Sr) and calcium (Ca) cumulative releases in physiological solution are in agreement with the greater solubility of SrHA than HA, whereas the differences between the two materials are levelled off in DMEM, which significantly reduced ion release. O-OB cells grown on SrHA exhibited higher proliferation and increased values of the differentiation parameters. In particular, Sr substitution increased the levels of proliferation, alkaline phosphatase, and collagen type I, and down-regulated the production of interleukin-6 of O-OB cells, demonstrating a promising future of SrHA in the treatment of bone lesions and defects in the presence of osteoporotic bone.
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Affiliation(s)
- E Boanini
- Department of Chemistry G. Ciamician, University of Bologna, Bologna, Italy
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30
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Panzavolta S, Torricelli P, Bracci B, Fini M, Bigi A. Functionalization of biomimetic calcium phosphate bone cements with alendronate. J Inorg Biochem 2010; 104:1099-106. [PMID: 20638728 DOI: 10.1016/j.jinorgbio.2010.06.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 06/17/2010] [Accepted: 06/18/2010] [Indexed: 11/28/2022]
Abstract
Bisphosphonates (BPs) are widely employed for the treatment of a variety of bone disorders. We have previously successfully added small amounts of BPs into calcium phosphate bone cements in order to enhance their bio-functionality. In this work we were able to increase greatly the amount of BP introduced in the cement, thanks to suitable modifications of composition. In particular, we utilized biomimetic alpha-tricalcium phosphate (alpha-TCP) cements at different gelatin contents (10, 15 and 20 wt.%) to introduce Disodium Alendronate up to a concentration of 25 mM. Due to the small liquid/powder ratio (0.22 ml/g) the lengthening of the setting times due to alendronate is quite modest. The rate of transformation of alpha-TCP into calcium deficient hydroxyapatite slightly decreases as a function of alendronate content, whereas it increases with increasing gelatin concentration. Moreover, relatively high alendronate concentrations provoke significant reduction of the compressive strength of the cements. The results of in vitro tests indicate that alendronate-containing cements significantly affect osteoclast proliferation and differentiation, whereas they promote osteoblast differentiation, to an extent which depends on cement composition.
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Affiliation(s)
- S Panzavolta
- Department of Chemistry G. Ciamician, University of Bologna, Bologna, Italy
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31
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Boanini E, Gazzano M, Bigi A. Ionic substitutions in calcium phosphates synthesized at low temperature. Acta Biomater 2010; 6:1882-94. [PMID: 20040384 DOI: 10.1016/j.actbio.2009.12.041] [Citation(s) in RCA: 353] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/16/2009] [Accepted: 12/21/2009] [Indexed: 11/29/2022]
Abstract
Ionic substitutions have been proposed as a tool to improve the biological performance of calcium phosphate based materials. This review provides an overview of the recent results achieved on ion-substituted calcium phosphates prepared at low temperature, i.e. by direct synthesis in aqueous medium or through hydrolysis of more soluble calcium phosphates. Particular attention is focused on several ions, including Si, Sr, Mg, Zn and Mn, which are attracting increasing interest for their possible biological role, and on the recent trends and developments in the applications of ion-substituted calcium phosphates in the biomedical field.
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Affiliation(s)
- E Boanini
- Department of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, Italy
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32
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Boanini E, Panzavolta S, Rubini K, Gandolfi M, Bigi A. Effect of strontium and gelatin on the reactivity of alpha-tricalcium phosphate. Acta Biomater 2010; 6:936-42. [PMID: 19819353 DOI: 10.1016/j.actbio.2009.10.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 09/30/2009] [Accepted: 10/05/2009] [Indexed: 10/20/2022]
Abstract
The hydrolysis reaction of alpha-tricalcium phosphate (alpha-TCP) is of great interest because of its widespread use in the preparation of biomaterials for hard tissue repair. The aim of this study was to investigate how this reaction is influenced by the presence of a bioactive ion, Sr(2+), and of a biopolymer, gelatin, which were previously reported to affect the setting reaction of alpha-TCP-based cements. Hydrolysis experiments were carried out at different Sr(2+) concentrations (0, 5, 10, 20 at.%) in solutions at different gelatin concentrations (0, 0.1, 0.5, 1.0 wt.%). The results indicate that Sr(2+) delays the conversion of alpha-TCP into calcium-deficient hydroxyapatite (CDHA). The structural and morphological modifications of CDHA obtained from solutions at increasing Sr(2+) concentrations indicate that during hydrolysis strontium enters the structure of CDHA, where it partially substitutes for calcium. On the contrary, alpha-TCP hydrolysis rate increases on increasing gelatin concentration. Gelatin promotes conversion of alpha-TCP into octacalcium phosphate, and strongly interacts with the nucleating and growing crystals.
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Bigi A, Morosi L, Pozzi C, Forcella M, Tettamanti G, Venerando B, Monti E, Fusi P. Human sialidase NEU4 long and short are extrinsic proteins bound to outer mitochondrial membrane and the endoplasmic reticulum, respectively. Glycobiology 2009; 20:148-57. [PMID: 19797320 DOI: 10.1093/glycob/cwp156] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sialidases are widely distributed glycohydrolytic enzymes removing sialic acid residues from glycoconjugates. In mammals, several sialidases with different subcellular localizations and biochemical features have been described. NEU4, the most recently identified member of the human sialidase family, is found in two forms, NEU4 long and NEU4 short, differing in the presence of a 12-amino-acid sequence at the N-terminus. Contradictory data are present in the literature about the subcellular distribution of these enzymes, their membrane anchoring mechanism being still unclear. In this work, we investigate the human NEU4 long and NEU4 short membrane anchoring mechanism and their subcellular localization. Protein extraction with Triton X-114 and sodium carbonate and cross-linking experiments demonstrate that both forms of NEU4 are extrinsic membrane proteins, anchored via protein-protein interactions. Moreover, through confocal microscopy and subcellular fractionation, we show that the long form localizes in mitochondria, while the short form is also associated with the endoplasmic reticulum. Finally, mitochondria subfractionation experiments suggest that NEU4 long is bound to the outer mitochondrial membrane.
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Affiliation(s)
- Alessandra Bigi
- Department of Biotechnologies and Biosciences, University of Milan-Bicocca, Piazza della Scienza, 2, 20126, Milano
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Capuccini C, Torricelli P, Boanini E, Gazzano M, Giardino R, Bigi A. Interaction of Sr-doped hydroxyapatite nanocrystals with osteoclast and osteoblast-like cells. J Biomed Mater Res A 2009; 89:594-600. [DOI: 10.1002/jbm.a.31975] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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35
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Panzavolta S, Fini M, Nicoletti A, Bracci B, Rubini K, Giardino R, Bigi A. Porous composite scaffolds based on gelatin and partially hydrolyzed alpha-tricalcium phosphate. Acta Biomater 2009; 5:636-43. [PMID: 18819853 DOI: 10.1016/j.actbio.2008.08.017] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 07/30/2008] [Accepted: 08/29/2008] [Indexed: 11/25/2022]
Abstract
Porous composite scaffolds of varying compositions were prepared by freeze-drying gelatin foams containing increasing amounts of alpha-tricalcium phosphate (alpha-TCP), up to about 40 wt.%. Due to the presence of gelatin, a partial hydrolysis of alpha-TCP into octacalcium phosphate (OCP) occurs during foaming. As a consequence, the scaffolds contain both alpha-TCP and OCP, in relative amounts of about 74% and 26%, respectively, independent of the initial composition. In physiological conditions the inorganic component of the scaffolds undergoes a further hydrolysis as shown by the finding that after immersion in phosphate-buffered saline at 37 degrees C for 1 week the scaffolds contain poorly crystalline hydroxyapatite together with OCP. The scaffolds display a porous interconnected microstructure. The mean dimensions of the pores decrease from about 350 to about 170 microm as the inorganic phase content increases. Simultaneously, the mean values of the compression strength and Young's modulus increase. Stabilization of the scaffolds was obtained by using a natural, non-toxic, crosslinking agent, genipin, which significantly improves their mechanical properties.
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Capuccini C, Torricelli P, Sima F, Boanini E, Ristoscu C, Bracci B, Socol G, Fini M, Mihailescu IN, Bigi A. Strontium-substituted hydroxyapatite coatings synthesized by pulsed-laser deposition: in vitro osteoblast and osteoclast response. Acta Biomater 2008; 4:1885-93. [PMID: 18554996 DOI: 10.1016/j.actbio.2008.05.005] [Citation(s) in RCA: 286] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 04/30/2008] [Accepted: 05/09/2008] [Indexed: 11/28/2022]
Abstract
The increasing interest in strontium incorporation into biomaterials for hard tissue repair is justified by the growing evidence of its beneficial effect on bone. We successfully synthesized hydroxyapatite (HA) thin films with different extents of strontium substitution for calcium (0, 1, 3 or 7 at.%) by pulsed-laser deposition. The coatings displayed a granular surface and a good degree of crystallinity, which slightly diminished as strontium content increased. Osteoblast-like MG63 cells and human osteoclasts were cultured on the thin films up to 21 days. MG63 cells grown on the strontium-doped HA coatings displayed normal morphology, good proliferation and increased values of the differentiation parameters, whereas the number of osteoclasts was negatively influenced by the presence of strontium. The positive effect of the ion on bone cells was particularly evident in the case of coatings deposited from HA at relatively high strontium contents (3-7%), where significantly increased values of alkaline phosphatase activity, osteocalcin, type I collagen and osteoprotegerin/TNF-related activation-induced cytokine receptor ratio, and considerably reduced values of osteoclast proliferation, were observed.
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Affiliation(s)
- C Capuccini
- Department of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, Italy
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37
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Panzavolta S, Torricelli P, Bracci B, Fini M, Bigi A. Alendronate and Pamidronate calcium phosphate bone cements: setting properties and in vitro response of osteoblast and osteoclast cells. J Inorg Biochem 2008; 103:101-6. [PMID: 18977031 DOI: 10.1016/j.jinorgbio.2008.09.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/21/2008] [Accepted: 09/18/2008] [Indexed: 10/21/2022]
Abstract
We have investigated the effect of Alendronate and Pamidronate, two bisphosphonates widely employed for the treatment of pathologies related to bone loss, on the setting properties and in vitro bioactivity of a calcium phosphate bone cement. The cement composition includes alpha-tricalcium phosphate (alpha-TCP) (90 wt%), nanocrystalline hydroxyapatite (5 wt%) and CaHPO(4) x 2H(2)O (5 wt%). Disodium Alendronate and disodium Pamidronate were added to the liquid phase (bidistilled water) at two different concentrations: 0.4 and 1mM (AL0.4, AL1.0, PAM0.4, PAM1.0). Both the initial and the final setting times of the bisphosphonate-containing cements increase with respect to the control cement. X-ray diffraction analysis, mechanical tests, and SEM investigations were carried out on the cements after different times of soaking in physiological solution. The rate of transformation of alpha-TCP into calcium deficient hydroxyapatite, as well as the microstructure of the cements, is not affected by the presence of Alendronate and Pamidronate. At variance, the bisphosphonates provoke a modest worsening of the mechanical properties. MG63 osteoblasts grown on the cements show a normal morphology and biological tests demonstrate very good rate of proliferation and viability in every experimental time. In particular, both Alendronate and Pamidronate promote osteoblast proliferation and differentiation, whereas they inhibit osteoclastogenesis and osteoclast function.
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Affiliation(s)
- S Panzavolta
- Department of Chemistry G Ciamician, University of Bologna, Bologna, Italy
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Pozzi C, Valtorta M, Tedeschi G, Galbusera E, Pastori V, Bigi A, Nonnis S, Grassi E, Fusi P. Study of subcellular localization and proteolysis of ataxin-3. Neurobiol Dis 2008; 30:190-200. [PMID: 18353661 DOI: 10.1016/j.nbd.2008.01.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 01/15/2008] [Accepted: 01/19/2008] [Indexed: 11/19/2022] Open
Abstract
In this work we investigate subcellular localization and proteolytic cleavage of different forms of ataxin-3 (AT-3), the protein responsible for spinocerebellar ataxia type 3. Normal (AT-3Q6 and AT-3Q26) and pathological (AT-3Q72) ataxins-3, as well as two truncated forms lacking poly-Q, were studied. Full-length proteins were also expressed as C14A mutants, in order to assess whether AT-3 autoproteolytic activity was involved in its fragmentation. We found that both normal and pathological proteins localized in the cytoplasm and in the nucleus, as expected, but also in the mitochondria. Microsequencing showed that all ataxins-3 underwent the same proteolytic cleavage, removing the first 27 amino acids. Interestingly, while normal ataxins were further cleaved at a number of caspase sites, pathological AT-3 was proteolyzed to a much lesser extent. This may play a role in the pathogenesis, hampering degradation of aggregation-prone expanded AT-3. In addition, autolytic cleavage was apparently not involved in AT-3 proteolysis.
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Affiliation(s)
- Chiara Pozzi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, P.za della Scienza 2, 20126 Milan, Italy
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Panzavolta S, Torricelli P, Sturba L, Bracci B, Giardino R, Bigi A. Setting properties andin vitro bioactivity of strontium-enriched gelatin–calcium phosphate bone cements. J Biomed Mater Res A 2008; 84:965-72. [PMID: 17647240 DOI: 10.1002/jbm.a.31412] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Strontium is known to reduce bone resorption and stimulate bone formation. We have investigated the effect of strontium on the setting properties and in vitro bioactivity of a biomimetic gelatin-calcium phosphate bone cement. Gelatin-alpha-TCP powders, with a gelatin content of 15 wt %, were prepared by grinding and sieving the solid compounds obtained by casting gelatin aqueous solutions containing alpha-TCP. 5 wt % of CaHPO(4).2H(2)O were added to the cement powders before mixing with the liquid phase, with a L/P ratio of 0.3 mL/g. Strontium was added as SrCl(2).6H(2)O in different amounts up to 5 atom %. X-ray diffraction analysis, mechanical tests, and SEM investigations were carried out on the cements after different times of soaking in physiological solution. The presence of strontium affects both the initial and the final setting times of the cements, which increase with the ion content. The microstructural modifications observed in the SEM micrographs of the fractured surfaces are in agreement with the increase of the total porosity, and with the slight reduction of the compressive strength of the aged cements, on increasing strontium content. The rate of transformation of alpha-TCP into calcium deficient hydroxyapatite increases on increasing strontium content. SEM reveals that MG63 osteoblasts grown on the cements show a normal morphology and biological tests demonstrate very good rate of proliferation and viability in every experimental time. In particular, strontium stimulates Alkaline Phosphatase activity, Collagen type I, osteocalcin, and osteoprotegerin expression.
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Affiliation(s)
- S Panzavolta
- Department of Chemistry "G. Ciamician," University of Bologna, 40126 Bologna, Italy
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Bigi A, Nicoli-Aldini N, Bracci B, Zavan B, Boanini E, Sbaiz F, Panzavolta S, Zorzato G, Giardino R, Facchini A, Abatangelo G, Cortivo R. In vitro culture of mesenchymal cells onto nanocrystalline hydroxyapatite-coated Ti13Nb13Zr alloy. J Biomed Mater Res A 2007; 82:213-21. [PMID: 17266017 DOI: 10.1002/jbm.a.31132] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study we coated a new biocompatible, nanostructured titanium alloy, Ti13Nb13Zr, with a thin layer of hydroxyapatite nanocrystals and we investigated the response of human bone-marrow-derived mesenchymal cells. The coating was realized using a slightly supersaturated CaP solution, which provokes a fast deposition of nanocrystalline hydroxyapatite. A thin layer of deposition is appreciable on the etched Ti13Nb13Zr substrates after just 1.5 h soaking in the CaP solution, and it reaches a thickness of 1-2 mum after 3 h soaking. The coating seems thinner than that deposited on Ti6Al4V, which was examined for comparison, likely because of the different roughness profiles of the two etched alloys, and it is constituted of elongated HA nanocrystals, with a mean length of about 100 nm. Mesenchymal stem cells were seeded onto coated and uncoated Ti alloys and cultured for up to 35 days. Cell morphology, proliferation and differentiation were evaluated. The cells display good adhesion and proliferation on the uncoated substrates, whereas the presence of hydroxyapatite coating slightly reduces cell proliferation and induces differentiation of MSCs towards a phenotypic osteoblastic lineage, in agreement with the increase of the expression of osteopontin, osteonectin and collagen type I, evaluated by means of rt-PCR. Type I collagen expression is higher in Ti13Nb13Zr MSC culture compared to Ti6Al4V, standing for a more efficient extracellular matrix deposition.
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Affiliation(s)
- A Bigi
- Department of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, Italy.
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Bigi A, Panzavolta S, Sturba L, Torricelli P, Fini M, Giardino R. Normal and osteopenic bone‐derived osteoblast response to a biomimetic gelatin–calcium phosphate bone cement. J Biomed Mater Res A 2006; 78:739-45. [PMID: 16739178 DOI: 10.1002/jbm.a.30765] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have recently developed a new calcium phosphate bone cement enriched with gelatin (GEL-CP), which exhibits improved mechanical properties with respect to the control cement (C-CP). In a previous study, we demonstrated the good response of osteoblast-like cells to the new biomimetic bone cement. Herein, we extend the investigation to primary culture of osteoblasts derived from healthy and pathological bones. Osteoblasts derived from normal (N-OB) and osteopenic (O-OB) sheep bones were cultured on samples of GEL-CP, and their behavior was compared with that of cells cultured on C-CP as control. Cell morphology, proliferation, and differentiation were evaluated at 3 and 7 days. SEM analysis revealed that both N-OB and O-OB showed a normal morphology when cultured on GEL-CP. Biological tests demonstrated that the gelatin-enriched cement improves osteoblasts' activity and differentiation of O-OB cultures, with respect to the control samples. The data indicate that the new composite cement positively stimulates alkaline phosphatase activity, collagen type I, and osteocalcin production, not only in N-OB, but also in O-OB culture. The improvement due to the presence of gelatin suggests that the biomimetic composite material could be successfully applied as bone substitute also in the presence of osteopenic bone.
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Affiliation(s)
- A Bigi
- Department of Chemistry "G. Ciamician, " University of Bologna, 40126 Bologna, Italy.
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Bigi A, Boanini E, Gazzano M, Rubini K. Structural and morphological modifications of hydroxyapatite-polyaspartate composite crystals induced by heat treatment. Cryst Res Technol 2005. [DOI: 10.1002/crat.200410493] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Boanini E, Gazzano M, Rubini K, Bigi A. Hydroxyapatite-bisphosphonate nanocrystals. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305085016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Bigi A, Bracci B, Cuisinier F, Elkaim R, Fini M, Mayer I, Mihailescu IN, Socol G, Sturba L, Torricelli P. Human osteoblast response to pulsed laser deposited calcium phosphate coatings. Biomaterials 2005; 26:2381-9. [PMID: 15585241 DOI: 10.1016/j.biomaterials.2004.07.057] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Accepted: 07/23/2004] [Indexed: 11/16/2022]
Abstract
Octacalcium phosphate (OCP) and Mn(2+)-doped carbonate hydroxyapatite (Mn-CHA) thin films were deposited on pure, highly polished and chemically etched Ti substrates with pulsed laser deposition. The coatings exhibit different composition, crystallinity and morphology that might affect their osteoconductivity. Human osteoblasts were cultured on the surfaces of OCP and Mn-CHA thin films, and the cell attachment, proliferation and differentiation were evaluated up to 21 days. The cells showed a normal morphology and a very good rate of proliferation and viability in every experimental time. Alkaline phosphatase activity was always higher than the control and Ti groups. From days 7 to 21 collagen type I production was higher in comparison with control and Ti groups. The level of transforming growth factor beta 1 (TGF-beta1) was lower at 3 and 7 days, but reached the highest values during following experimental times (14 and 21 days). Our data demonstrate that both calcium phosphate coatings favour osteoblasts proliferation, activation of their metabolism and differentiation.
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Affiliation(s)
- A Bigi
- Department of Chemistry "G. Ciamician", University of Bologna, via Selmi, 2, Bologna 40126, Italy.
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Bigi A, Panzavolta S, Rubini K. Relationship between triple-helix content and mechanical properties of gelatin films. Biomaterials 2005; 25:5675-80. [PMID: 15159084 DOI: 10.1016/j.biomaterials.2004.01.033] [Citation(s) in RCA: 282] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Accepted: 01/16/2004] [Indexed: 12/01/2022]
Abstract
This paper reports a study on the influence of the renaturation level of gelatin on the mechanical and swelling properties of gelatin films. Films at different renaturation level were obtained from gelatin samples with different Bloom index. It was verified that the triple-helix content, calculated from the values of the enthalpy of denaturation associated to the endothermal transition at about 41 degrees C of gelatin, increases with the Bloom index. The d.s.c. data are further supported by the results of the X-ray diffraction investigation carried out on the same samples. The increase of triple-helix content provokes a significant reduction in the degree of swelling, and a remarkable improvement of the mechanical properties of the films. The elastic Young's modulus, E, increases linearly with the renaturation level, from 3.6 to 12.0 MPa. Crosslinking with GTA 1% remarkably reduces the degree of swelling of all the samples, and induces a further increase of the Young's modulus, which reaches values up to 27 MPa.
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Affiliation(s)
- A Bigi
- Department of Chemistry, University of Bologna, via Selmi, 2, Bologna 40126, Italy.
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Abstract
The interest in new bone substitutes is rapidly increasing in the field of orthopedic surgery. A variety of calcium phosphate bone cement has been developed and different additives have been used to improve their biocompatibility and bioactivity. Following a biomimetic strategy aimed at reproducing bone characteristics, this study investigates the biological properties of a new gelatin enriched calcium phosphate cement (GEL-CP) that exhibits improved mechanical properties with respect to cement prepared without gelatin (C-CP). Human osteoblast MG63 were cultured on the surfaces of GEL-CP and were compared to cells cultured on C-CP samples, and on polystyrene of plate culture as control (C). Cell attachment, proliferation and differentiation were evaluated up to 21 days. SEM revealed that osteoblasts grown on GEL-CP showed a normal morphology and biological tests demonstrated very good rate of proliferation and viability in every experimental time. The presence of gelatin stimulated alkaline phosphatase activity, collagen and transforming growth factor 31 production. The data indicate that the new cement GEL-CP favors osteoblast proliferation, activation of their metabolism and differentiation. The remarkable improvement of the setting properties of the calcium phosphate cement due to the presence of gelatin suggest that the biomimetic composite material could be successfully applied as bone substitute.
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Affiliation(s)
- A Bigi
- Department of Chemistry G. Ciamician, University of Bologna, Bologna, Italy
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György E, Toricelli P, Socol G, Iliescu M, Mayer I, Mihailescu IN, Bigi A, Werckman J. Biocompatible Mn2+-doped carbonated hydroxyapatite thin films grown by pulsed laser deposition. J Biomed Mater Res A 2004; 71:353-8. [PMID: 15372467 DOI: 10.1002/jbm.a.30172] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mn(2+)-doped carbonated hydroxyapatite (Mn-CHA) thin films were obtained by pulsed laser deposition on Ti substrates. The results of the performed complementary diagnostic techniques, X-ray diffraction, infrared spectroscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy investigations indicate that the films are crystalline with a Ca/P ratio of about 1.64-1.66. The optimum conditions, when nearly stoichiometric crystalline thin films were deposited, were found to be 10 Pa oxygen pressure, 400 degrees C substrate temperature, and postdeposition heat treatment in water vapors at the same substrate temperature. The films were seeded with L929 fibroblast and hFOB1.19 osteoblast cells and subjected to in vitro tests. Both fibroblast and osteoblast cells have a good adherence on the Mn-CHA film and on the Ti or polystyrene references. Proliferation and viability tests showed that osteoblast cells growth on Mn-CHA-coated Ti was enhanced as compared to uncoated pure Ti surfaces. Caspase-1 activity was not affected significantly by the material, showing that Mn-CHA does not induce apoptosis of cultured cells. These results demonstrate that Mn-CHA films on Ti should provoke a faster osteointegration of the coated implants as compared to pure Ti. (c) 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 353-358, 2004.
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Affiliation(s)
- E György
- National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele, Romania
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Abstract
This study investigates the effect of gelatin on the setting time, compressive strength, phase evolution and microstructure of calcium phosphate cement. The composite cement powder (about 18 wt% gelatin, and 82 wt% alpha-tricalcium phosphate) was prepared from the solid compound obtained by casting a gelatin aqueous solution containing alpha-tricalcium phosphate. 5 wt% of CaHPO(4) x 2H(2)O were added to the powder before mixing with the liquid phase. Two cement formulations were prepared using two different liquid/powder ratios, and their properties compared with those of control samples, prepared without gelatin. The final setting time increases from 10 min to more than 45 min when the L/P ratio increases from 0.3 to 0.4 ml/g. The presence of gelatin accelerates the setting reaction, and improves the mechanical properties of the cements. The compressive strength increases with the setting reaction up to 10.7-14.0 MPa for the gelatin cements, whereas the control samples exhibit much lower values. The improved mechanical properties of the composite cements with respect to the controls can be related to their reduced total porosity and more compact microstructure.
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Affiliation(s)
- A Bigi
- Department of Chemistry "G. Ciamician", University of Bologna, 40126 Bologna, Italy.
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Bigi A, Cantelli I, Panzavolta S, Rubini K. Alpha-Tricalcium phosphate-gelatin composite cements. J Appl Biomater Biomech 2004; 2:81-87. [PMID: 20803441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This study investigates gelatin influence on calcium phosphate cement (CPC) setting properties. Cements of different compositions were prepared using |Alpha -tricalcium phosphate (|Alpha -TCP) enriched with a small amount of dicalcium phosphate dihydrate (DCPD), and different gelatin amounts up to 20 wt%. The cements, prepared with a liquid/powder ratio of 0.3 ml/g, were soaked in simulated body fluid (SBF) for different times inverted exclamation markU21 days. The setting reaction of the control cement prepared without gelatin occurred in 7 days, whereas the transformation of the cements at high gelatin content into apatite was almost complete in 2-day aging in SBF. Gelatin presence reduced the total porosity of the cements, and significantly modified their microstructure. The fractured surface of the aged control cement was covered with entangled plate-like apatite crystals, whereas the gelatin cements displayed more compact surfaces, most likely due to the inhibiting effect of gelatin on apatite crystal growth. The microstructural modifications were in agreement with the mprovement of the mechanical properties in the aged cements, the compressive strength of which increased linearly as a function of gelatin content, from 2.0 inverted exclamation markA 0.8 to 14 inverted exclamation markA 1 MPa.
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Affiliation(s)
- A Bigi
- Department of Chemistry ""G. Ciamician"", University of Bologna, Bologna - Italy
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