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Magrì A, Tabbì G, Naletova I, Attanasio F, Arena G, Rizzarelli E. A Deeper Insight in Metal Binding to the hCtr1 N-terminus Fragment: Affinity, Speciation and Binding Mode of Binuclear Cu 2+ and Mononuclear Ag + Complex Species. Int J Mol Sci 2022; 23:ijms23062929. [PMID: 35328348 PMCID: PMC8953729 DOI: 10.3390/ijms23062929] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 01/27/2023] Open
Abstract
Ctr1 regulates copper uptake and its intracellular distribution. The first 14 amino acid sequence of the Ctr1 ectodomain Ctr1(1-14) encompasses the characteristic Amino Terminal Cu2+ and Ni2+ binding motif (ATCUN) as well as the bis-His binding motif (His5 and His6). We report a combined thermodynamic and spectroscopic (UV-vis, CD, EPR) study dealing with the formation of Cu2+ homobinuclear complexes with Ctr1(1-14), the percentage of which is not negligible even in the presence of a small Cu2+ excess and clearly prevails at a M/L ratio of 1.9. Ascorbate fails to reduce Cu2+ when bound to the ATCUN motif, while it reduces Cu2+ when bound to the His5-His6 motif involved in the formation of binuclear species. The histidine diade characterizes the second binding site and is thought to be responsible for ascorbate oxidation. Binding constants and speciation of Ag+ complexes with Ctr1(1-14), which are assumed to mimic Cu+ interaction with N-terminus of Ctr1(1-14), were also determined. A preliminary immunoblot assay evidences that the anti-Ctr1 extracellular antibody recognizes Ctr1(1-14) in a different way from the longer Ctr1(1-25) that encompasses a second His and Met rich domain.
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Affiliation(s)
- Antonio Magrì
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
| | - Giovanni Tabbì
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
| | - Irina Naletova
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
- Consorzio Interuniversitario per la Ricerca dei Metalli nei Sistemi Biologici, Via Ulpiani 27, 70126 Bari, Italy
| | - Francesco Attanasio
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
- Correspondence: (F.A.); (E.R.); Tel.: +39-095-7385070 (E.R.)
| | - Giuseppe Arena
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy;
| | - Enrico Rizzarelli
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
- Consorzio Interuniversitario per la Ricerca dei Metalli nei Sistemi Biologici, Via Ulpiani 27, 70126 Bari, Italy
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy;
- Correspondence: (F.A.); (E.R.); Tel.: +39-095-7385070 (E.R.)
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2
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Wallin C, Jarvet J, Biverstål H, Wärmländer S, Danielsson J, Gräslund A, Abelein A. Metal ion coordination delays amyloid-β peptide self-assembly by forming an aggregation-inert complex. J Biol Chem 2020; 295:7224-7234. [PMID: 32241918 PMCID: PMC7247290 DOI: 10.1074/jbc.ra120.012738] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/01/2020] [Indexed: 01/28/2023] Open
Abstract
A detailed understanding of the molecular pathways for amyloid-β (Aβ) peptide aggregation from monomers into amyloid fibrils, a hallmark of Alzheimer's disease, is crucial for the development of diagnostic and therapeutic strategies. We investigate the molecular details of peptide fibrillization in vitro by perturbing this process through addition of differently charged metal ions. Here, we used a monovalent probe, the silver ion, that, similarly to divalent metal ions, binds to monomeric Aβ peptide and efficiently modulates Aβ fibrillization. On the basis of our findings, combined with our previous results on divalent zinc ions, we propose a model that links the microscopic metal-ion binding to Aβ monomers to its macroscopic impact on the peptide self-assembly observed in bulk experiments. We found that substoichiometric concentrations of the investigated metal ions bind specifically to the N-terminal region of Aβ, forming a dynamic, partially compact complex. The metal-ion bound state appears to be incapable of aggregation, effectively reducing the available monomeric Aβ pool for incorporation into fibrils. This is especially reflected in a decreased fibril-end elongation rate. However, because the bound state is significantly less stable than the amyloid state, Aβ peptides are only transiently redirected from fibril formation, and eventually almost all Aβ monomers are integrated into fibrils. Taken together, these findings unravel the mechanistic consequences of delaying Aβ aggregation via weak metal-ion binding, quantitatively linking the contributions of specific interactions of metal ions with monomeric Aβ to their effects on bulk aggregation.
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Affiliation(s)
- Cecilia Wallin
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Henrik Biverstål
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, 141 52 Huddinge, Sweden; Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga LV-1006, Latvia
| | - Sebastian Wärmländer
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Jens Danielsson
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Axel Abelein
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, 141 52 Huddinge, Sweden.
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3
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Bacchella C, Gentili S, Bellotti D, Quartieri E, Draghi S, Baratto MC, Remelli M, Valensin D, Monzani E, Nicolis S, Casella L, Tegoni M, Dell'Acqua S. Binding and Reactivity of Copper to R 1 and R 3 Fragments of tau Protein. Inorg Chem 2019; 59:274-286. [PMID: 31820933 DOI: 10.1021/acs.inorgchem.9b02266] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tau protein is present in significant amounts in neurons, where it contributes to the stabilization of microtubules. Insoluble neurofibrillary tangles of tau are associated with several neurological disorders known as tauopathies, among which is Alzheimer's disease. In neurons, tau binds tubulin through its microtubule binding domain which comprises four imperfect repeats (R1-R4). The histidine residues contained in these fragments are potential binding sites for metal ions and are located close to the regions that drive the formation of amyloid aggregates of tau. In this study, we present a detailed characterization through potentiometric and spectroscopic methods of the binding of copper in both oxidation states to R1 and R3 peptides, which contain one and two histidine residues, respectively. We also evaluate how the redox cycling of copper bound to tau peptides can mediate oxidation that can potentially target exogenous substrates such as neuronal catecholamines. The resulting quinone oxidation products undergo oligomerization and can competitively give post-translational peptide modifications yielding catechol adducts at amino acid residues. The presence of His-His tandem in the R3 peptide strongly influences both the binding of copper and the reactivity of the resulting copper complex. In particular, the presence of the two adjacent histidines makes the copper(I) binding to R3 much stronger than in R1. The copper-R3 complex is also much more active than the copper-R1 complex in promoting oxidative reactions, indicating that the two neighboring histidines activate copper as a catalyst in molecular oxygen activation reactions.
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Affiliation(s)
- Chiara Bacchella
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Silvia Gentili
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale , Università di Parma , Parco Area delle Scienze 11/A , 43124 Parma , Italy
| | - Denise Bellotti
- Dipartimento di Scienze Chimiche e Farmaceutiche , Università di Ferrara , Via Luigi Borsari 46 , 44121 Ferrara , Italy
| | - Eleonora Quartieri
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale , Università di Parma , Parco Area delle Scienze 11/A , 43124 Parma , Italy
| | - Sara Draghi
- Dipartimento di Biotecnologie, Chimica e Farmacia , Università di Siena , Via A. Moro 2 , 53100 , Siena , Italy
| | - Maria Camilla Baratto
- Dipartimento di Biotecnologie, Chimica e Farmacia , Università di Siena , Via A. Moro 2 , 53100 , Siena , Italy
| | - Maurizio Remelli
- Dipartimento di Scienze Chimiche e Farmaceutiche , Università di Ferrara , Via Luigi Borsari 46 , 44121 Ferrara , Italy
| | - Daniela Valensin
- Dipartimento di Biotecnologie, Chimica e Farmacia , Università di Siena , Via A. Moro 2 , 53100 , Siena , Italy
| | - Enrico Monzani
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Stefania Nicolis
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Luigi Casella
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
| | - Matteo Tegoni
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale , Università di Parma , Parco Area delle Scienze 11/A , 43124 Parma , Italy
| | - Simone Dell'Acqua
- Dipartimento di Chimica , Università di Pavia , Via Taramelli 12 , 27100 Pavia , Italy
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4
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De Gregorio G, Biasotto F, Hecel A, Luczkowski M, Kozlowski H, Valensin D. Structural analysis of copper(I) interaction with amyloid β peptide. J Inorg Biochem 2019; 195:31-38. [DOI: 10.1016/j.jinorgbio.2019.03.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 12/01/2022]
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5
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Hecel A, Kolkowska P, Krzywoszynska K, Szebesczyk A, Rowinska-Zyrek M, Kozlowski H. Ag+ Complexes as Potential Therapeutic Agents in Medicine and Pharmacy. Curr Med Chem 2019; 26:624-647. [DOI: 10.2174/0929867324666170920125943] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 07/28/2017] [Accepted: 08/09/2017] [Indexed: 12/17/2022]
Abstract
Silver is a non-essential element with promising antimicrobial and anticancer properties. This work is a detailed summary of the newest findings on the bioinorganic chemistry of silver, with a special focus on the applications of Ag+ complexes and nanoparticles. The coordination chemistry of silver is given a reasonable amount of attention, summarizing the most common silver binding sites and giving examples of such binding motifs in biologically important proteins. Possible applications of this metal and its complexes in medicine, particularly as antibacterial and antifungal agents and in cancer therapy, are discussed in detail. The most recent data on silver nanoparticles are also summarized.
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Affiliation(s)
- Aleksandra Hecel
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50383 Wroclaw, Poland
| | - Paulina Kolkowska
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, via A. Moro 2, 53100 Siena, Italy
| | - Karolina Krzywoszynska
- Institute of Cosmetology, Public Higher Medical Professional School in Opole, Katowicka 68, 45060 Opole, Poland
| | - Agnieszka Szebesczyk
- Institute of Cosmetology, Public Higher Medical Professional School in Opole, Katowicka 68, 45060 Opole, Poland
| | | | - Henryk Kozlowski
- Institute of Cosmetology, Public Higher Medical Professional School in Opole, Katowicka 68, 45060 Opole, Poland
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6
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Hecel A, Valensin D, Kozłowski H. How copper ions and membrane environment influence the structure of the human and chicken tandem repeats domain? J Inorg Biochem 2018; 191:143-153. [PMID: 30529722 DOI: 10.1016/j.jinorgbio.2018.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/14/2022]
Abstract
Prion proteins (PrPs) from different species have the enormous ability to anchor copper ions. The N-terminal domain of human prion protein (hPrP) contains four tandem repeats of the -PHGGGWGQ- octapeptide sequence. This octarepeat domain can bind up to four Cu2+ ions. Similarly to hPrP, chicken prion protein (chPrP) is able to interact with Cu2+ through the tandem hexapeptide -HNPGYP- region (residues 53-94). In this work, we focused on the human octapeptide repeat (human Octa4, hPrP60-91) (Ac-PHGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQ-NH2) and chicken hexapeptide repeat (chicken Hexa4, chPrP54-77) (Ac-HNPGYPHNPGYPHNPGYPHNPGYP-NH2) prion protein fragments. Due to the fact that PrP is a membrane-anchored glycoprotein and its unstructured and flexible N-terminal domain may interact with the lipid bilayer, our studies were carried out in presence of the surfactant sodium dodecyl sulfate (SDS) mimicking the membrane environment in vitro. The main objective of this work was to understand the effects of copper ion on the structural rearrangements of the human and chicken N-terminal repeat domain. The obtained results provide a fundamental first step in describing the thermodynamic (potentiometric titrations) and structural properties of Cu(II) binding (UV-Vis, NMR, CD spectroscopy) to both human Octa4 and chicken Hexa4 repeats in both a DMSO/water and SDS micelle environment. Interestingly, in SDS environment, both ligands indicate different copper coordination modes, which results of the conformational changes in micelle environment. Our results strongly support that copper binding mode strongly depends on the protein backbone structure. Moreover, we focused on previously obtained results for amyloidogenic human and chicken fragments in membrane mimicking environment.
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Affiliation(s)
- Aleksandra Hecel
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50383 Wroclaw, Poland.
| | - Daniela Valensin
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Henryk Kozłowski
- Opole Medical School in Opole, Katowicka 68, 45060 Opole, Poland
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7
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Sánchez-López C, Rivillas-Acevedo L, Cruz-Vásquez O, Quintanar L. Methionine 109 plays a key role in Cu(II) binding to His111 in the 92–115 fragment of the human prion protein. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.09.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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8
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Abbaoui A, Gamrani H. Neuronal, astroglial and locomotor injuries in subchronic copper intoxicated rats are repaired by curcumin: A possible link with Parkinson's disease. Acta Histochem 2018; 120:542-550. [PMID: 29954586 DOI: 10.1016/j.acthis.2018.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 01/05/2023]
Abstract
We aim herein to assess the neurotoxic effects of subchronic Cu-exposition (0125%) for 6 weeks on dopaminergic and astroglial systems then locomotor activity in rats as well as the probable therapeutic efficiency of curcumin-I (30 mg/kg B.W.). We found that intoxicated rats showed a significant impairment of Tyrosine Hydroxylase (TH) within substantia nigra pars compacta (SNc), ventral tegmental area (VTA) and the striatal outputs together with loss expression of GFAP in these structures. This was linked with an evident decrease in locomotor performance. Co-treatment with curcumin-I inverted these damages and exhibited a significant neuroprotective potential, thus, both TH expression and locomotor performance was reinstated in intoxicated rats. These results prove a profound dopaminergic and astroglial damages following subchronic Cu exposition and new beneficial curative potential of curcumin against subchronic Cu-induced astroglial and dopaminergic neurotoxicity. Consequently, we suggest that Cu neurotoxicity may be strengthened in vivo firstly by attacking and weaking the astroglial system, and curcumin could be prized as a powerful and preventive target for the neurodegenerative diseases related metal element, especially Parkinson's disease.
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9
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Kawahara M, Kato-Negishi M, Tanaka K. Cross talk between neurometals and amyloidogenic proteins at the synapse and the pathogenesis of neurodegenerative diseases. Metallomics 2018; 9:619-633. [PMID: 28516990 DOI: 10.1039/c7mt00046d] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increasing evidence suggests that disruption of metal homeostasis contributes to the pathogenesis of various neurodegenerative diseases, including Alzheimer's disease, prion diseases, Lewy body diseases, and vascular dementia. Conformational changes of disease-related proteins (amyloidogenic proteins), such as β-amyloid protein, prion proteins, and α-synuclein, are well-established contributors to neurotoxicity and to the pathogenesis of these diseases. Recent studies have demonstrated that these amyloidogenic proteins are metalloproteins that bind trace elements, including zinc, iron, copper, and manganese, and play significant roles in the maintenance of metal homeostasis. We present a current review of the role of trace elements in the functions and toxicity of amyloidogenic proteins, and propose a hypothesis integrating metal homeostasis and the pathogenesis of neurodegenerative diseases that is focused on the interactions among metals and between metals and amyloidogenic proteins at the synapse, considering that these amyloidogenic proteins and metals are co-localized at the synapse.
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Affiliation(s)
- M Kawahara
- Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo 202-8585, Japan.
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10
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Ivanova J, Petrova E, Kamenova K, Gluhcheva Y. Comparative effects of meso-2,3- dimercaptosuccinic acid, monensin, and salinomycin on cadmium-induced brain dysfunction in cadmium-intoxicated mice. Interdiscip Toxicol 2017; 10:107-113. [PMID: 30174534 PMCID: PMC6107650 DOI: 10.1515/intox-2017-0017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/02/2017] [Indexed: 12/15/2022] Open
Abstract
Cadmium (Cd) is a risk factor for neurodegenerative diseases. The purpose of this study was to compare the effects of meso-2,3-dimercaptosuccinic acid (DMSA) and the polyether ionophorous antibiotics monensin and salinomycin on Cd-induced neurodegenerative alterations in mice. The results show that subacute intoxication of mice with Cd (II) acetate (20 mg/kg body weight (BW) for 14 days) caused a significant accumulation of cadmium (Cd) in the brain. Treatment of Cd-exposed mice with DMSA (20 mg/kg BW for 14 days) significantly increased the Cd concentration in the brains compared to those of the Cd-treated group. However, administration of monensin (20 mg/kg BW for 14 days) or salinomycin (20 mg/kg BW for 14 days) significantly reduced the Cd concentration in the brains of Cd-treated mice compared to the toxic control group. Histopathological analysis of brain tissues from the Cd-treated mice revealed that Cd induced neuronal necrosis, characterized by many shrunken, darkly stained pyknotic neurons with prominent perineuronal spaces. Whereas monensin and salinomycin significantly reduced the adverse effects of Cd on brain morphology of Cd-treated mice, DMSA did not. Monensin slightly increased the copper and iron endogenous levels in the brains of Cd-exposed mice compared to those of the untreated mice. Salinomycin did not affect the concentrations of biometal ions in the brain of Cd-exposed mice compared to untreated controls. The results demonstrated salinomycin to be a better potential chelating agent for treatment of Cd-induced brain injury compared to DMSA and monensin.
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Affiliation(s)
- Juliana Ivanova
- Faculty of Medicine, Sofia University ‘St. Kliment Ohridski’, Kozjak Str., 1, 1407-Sofia, Bulgaria
| | - Emilia Petrova
- Institute of Experimental Morphology, Pathology and Anthropology with Museum, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Str., Bl. 25, 1113-Sofia, Bulgaria
| | - Kalina Kamenova
- Faculty of Chemistry and Pharmacy, Sofia University ‘St. Kliment Ohridski’, J. Bourchier Ave., 1, 1164 - Sofia, Bulgaria
| | - Yordanka Gluhcheva
- Institute of Experimental Morphology, Pathology and Anthropology with Museum, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Str., Bl. 25, 1113-Sofia, Bulgaria
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11
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Hecel A, De Ricco R, Valensin D. Influence of membrane environments and copper ions on the structural features of amyloidogenic proteins correlated to neurodegeneration. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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12
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Arcos-López T, Qayyum M, Rivillas-Acevedo L, Miotto MC, Grande-Aztatzi R, Fernández CO, Hedman B, Hodgson KO, Vela A, Solomon EI, Quintanar L. Spectroscopic and Theoretical Study of Cu(I) Binding to His111 in the Human Prion Protein Fragment 106-115. Inorg Chem 2016; 55:2909-22. [PMID: 26930130 PMCID: PMC4804749 DOI: 10.1021/acs.inorgchem.5b02794] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Indexed: 12/19/2022]
Abstract
The ability of the cellular prion protein (PrP(C)) to bind copper in vivo points to a physiological role for PrP(C) in copper transport. Six copper binding sites have been identified in the nonstructured N-terminal region of human PrP(C). Among these sites, the His111 site is unique in that it contains a MKHM motif that would confer interesting Cu(I) and Cu(II) binding properties. We have evaluated Cu(I) coordination to the PrP(106-115) fragment of the human PrP protein, using NMR and X-ray absorption spectroscopies and electronic structure calculations. We find that Met109 and Met112 play an important role in anchoring this metal ion. Cu(I) coordination to His111 is pH-dependent: at pH >8, 2N1O1S species are formed with one Met ligand; in the range of pH 5-8, both methionine (Met) residues bind to Cu(I), forming a 1N1O2S species, where N is from His111 and O is from a backbone carbonyl or a water molecule; at pH <5, only the two Met residues remain coordinated. Thus, even upon drastic changes in the chemical environment, such as those occurring during endocytosis of PrP(C) (decreased pH and a reducing potential), the two Met residues in the MKHM motif enable PrP(C) to maintain the bound Cu(I) ions, consistent with a copper transport function for this protein. We also find that the physiologically relevant Cu(I)-1N1O2S species activates dioxygen via an inner-sphere mechanism, likely involving the formation of a copper(II) superoxide complex. In this process, the Met residues are partially oxidized to sulfoxide; this ability to scavenge superoxide may play a role in the proposed antioxidant properties of PrP(C). This study provides further insight into the Cu(I) coordination properties of His111 in human PrP(C) and the molecular mechanism of oxygen activation by this site.
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Affiliation(s)
| | - Munzarin Qayyum
- Department of Chemistry, Stanford University, Stanford, California 94395, United States
| | | | - Marco C. Miotto
- Max Planck
Laboratory for Structural Biology, Chemistry and Molecular Biophysics
of Rosario (MPLbioR, UNR-MPIbpC) and Instituto de Investigaciones
para el Descubrimiento de Fármacos de Rosario (IIDEFAR, UNR-CONICET), Universidad Nacional de Rosario, Ocampo y Esmeralda, S2002LRK Rosario, Argentina
| | | | - Claudio O. Fernández
- Max Planck
Laboratory for Structural Biology, Chemistry and Molecular Biophysics
of Rosario (MPLbioR, UNR-MPIbpC) and Instituto de Investigaciones
para el Descubrimiento de Fármacos de Rosario (IIDEFAR, UNR-CONICET), Universidad Nacional de Rosario, Ocampo y Esmeralda, S2002LRK Rosario, Argentina
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC, Stanford University, Menlo Park, California 94025, United States
| | - Keith O. Hodgson
- Department of Chemistry, Stanford University, Stanford, California 94395, United States
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC, Stanford University, Menlo Park, California 94025, United States
| | - Alberto Vela
- Departamento
de Química, Cinvestav, Gustavo A. Madero, 07360 México
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California 94395, United States
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC, Stanford University, Menlo Park, California 94025, United States
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13
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Abstract
Metals play important roles in the human body, maintaining cell structure and regulating gene expression, neurotransmission, and antioxidant response, to name a few. However, excessive metal accumulation in the nervous system may be toxic, inducing oxidative stress, disrupting mitochondrial function, and impairing the activity of numerous enzymes. Damage caused by metal accumulation may result in permanent injuries, including severe neurological disorders. Epidemiological and clinical studies have shown a strong correlation between aberrant metal exposure and a number of neurological diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, autism spectrum disorders, Guillain–Barré disease, Gulf War syndrome, Huntington’s disease, multiple sclerosis, Parkinson’s disease, and Wilson’s disease. Here, we briefly survey the literature relating to the role of metals in neurodegeneration.
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Affiliation(s)
- Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, USA
| | - Mahfuzur Rahman Miah
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, USA
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