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Goldberg JM, Lippard SJ. Mobile zinc as a modulator of sensory perception. FEBS Lett 2023; 597:151-165. [PMID: 36416529 PMCID: PMC10108044 DOI: 10.1002/1873-3468.14544] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/24/2022]
Abstract
Mobile zinc is an abundant transition metal ion in the central nervous system, with pools of divalent zinc accumulating in regions of the brain engaged in sensory perception and memory formation. Here, we present essential tools that we developed to interrogate the role(s) of mobile zinc in these processes. Most important are (a) fluorescent sensors that report the presence of mobile zinc and (b) fast, Zn-selective chelating agents for measuring zinc flux in animal tissue and live animals. The results of our studies, conducted in collaboration with neuroscientist experts, are presented for sensory organs involved in hearing, smell, vision, and learning and memory. A general principle emerging from these studies is that the function of mobile zinc in all cases appears to be downregulation of the amplitude of the response following overstimulation of the respective sensory organs. Possible consequences affecting human behavior are presented for future investigations in collaboration with interested behavioral scientists.
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Affiliation(s)
| | - Stephen J Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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2
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Ishimaru T. Enhancement of olfaction by femtomolar concentrations of zinc ions. Neurosci Lett 2022; 788:136837. [PMID: 35963478 DOI: 10.1016/j.neulet.2022.136837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/28/2022]
Abstract
Zinc is recognized as an important element for olfaction. Zinc nanoparticles enhance olfaction in response to odors; however, the mechanisms underlying this action remain unknown. Herein, the effect of zinc on olfactory receptors was deduced using electro-olfactogram (EOG) responses recorded from the isolated olfactory mucosae of bullfrogs (Rana catesbeiana) following the administration or chelation of zinc ions. Menthone and n-amyl acetate were used as odorants, whereas forskolin (an adenylate cyclase activator) and cholera toxin (a Gαolf activator) were used as intracellular signal transduction activators. The EOG responses provoked by the odorants and cholera toxin were suppressed by dithizone-mediated zinc ion chelation, and the EOG responses were recovered by administering non-chelated zinc. However, the EOG response to forskolin was not suppressed by dithizone. In contrast, the addition of femtomolar concentrations of zinc ions enhanced the EOG responses. The above-mentioned effects on EOG responses were examined by changing the concentration of zinc ions but not zinc nanoparticles. The results of this study suggest that Gαolf alone or both olfactory receptors and Gαolf likely require zinc ions for their activation.
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Affiliation(s)
- Tadashi Ishimaru
- Department of Otorhinolaryngology, Hyotan-machi ENT Clinic, Hyotan-machi 2-13, Kanazawa 920-0845, Japan.
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3
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Ghorai P, Pal K, Karmakar P, Saha A. The development of two fluorescent chemosensors for the selective detection of Zn2+ and Al3+ ions in a quinoline platform by tuning the substituents in the receptor part: elucidation of the structures of the metal-bound chemosensors and biological studies. Dalton Trans 2020; 49:4758-4773. [DOI: 10.1039/c9dt04902a] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Two aminoquinoline-based chemosensors (HL1 and HL2) are reported for selective detection of Zn2+ and Al3+ ions.
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Affiliation(s)
- Pravat Ghorai
- Department of Chemistry
- Jadavpur University
- Kolkata-700032
- India
| | - Kunal Pal
- Department of Life Science and Biotechnology
- Jadavpur University
- Kolkata-700032
- India
| | - Parimal Karmakar
- Department of Life Science and Biotechnology
- Jadavpur University
- Kolkata-700032
- India
| | - Amrita Saha
- Department of Chemistry
- Jadavpur University
- Kolkata-700032
- India
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4
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Marszałek I, Goch W, Bal W. Ternary Zn(II) Complexes of Fluorescent Zinc Probes Zinpyr-1 and Zinbo-5 with the Low Molecular Weight Component of Exchangeable Cellular Zinc Pool. Inorg Chem 2019; 58:14741-14751. [PMID: 31646867 DOI: 10.1021/acs.inorgchem.9b02419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The intracellular exchangeable Zn(II) is usually measured with synthetic fluorescent zinc sensors. 4',5'-Bis[bis(2-pyridylmethyl)aminomethyl]-2',7'-dichlorofluorescein (Zinpyr-1) is a sensor containing the fluorescein platform and a duplicated chelating unit. Its advantages include brightness and a relatively high affinity for Zn(II), Kd = 0.7 nM. 2-(4,5-Dimethoxy-2-hydroxyphenyl)-4-(2-pyridylmethyl)aminomethylbenzoxazole (Zinbo-5) is a member of a growing family of ratiometric synthetic Zn(II) probes, offering a possibility to determine Zn(II) concentration independently of the sensor concentration. Cells, however, contain high, millimolar or nearly millimolar concentrations of low molecular weight ligands (LMWLs) capable of binding Zn(II) ions. Previously, we demonstrated that such LMWLs can perturb the performance of some fluorescent zinc sensors by competition and formation of ternary Zn(sensor) (LMWL) complexes. Here we tested Zinpyr-1 and Zinbo-5 in this respect. Despite structural differences, both sensors formed such ternary complexes. We determined their stability constants CKtern and performed numerical simulations of Zn(II) distributions at physiological concentrations of selected LMWLs. Glutamic acid was found to provide the strongest ternary complexes with either of the studied sensors. Zn(Zinpyr-1)(Glu) was an absolutely dominant Zn(II)/Zinpyr-1 species (more than 96% of the exchangeable Zn(II)), and Zn(Zinbo-5)(Glu) was the most abundant one (more than 40%) in these simulations. Our results indicate that under cellular conditions these sensors are able to report Zn(II) complexed to LMWLs rather than free Zn2+ ions. On the other hand, the specific affinity of Zn(Zinpyr-1) and Zn(Zinbo-5) for Glu creates interesting opportunities for determining glutamic acid in biological samples.
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Affiliation(s)
- Ilona Marszałek
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Goch
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland.,Faculty of Pharmacy , Medical University of Warsaw , Banacha 1 , 02-091 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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5
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Marszałek I, Goch W, Bal W. Ternary Zn(II) Complexes of FluoZin-3 and the Low Molecular Weight Component of the Exchangeable Cellular Zinc Pool. Inorg Chem 2018; 57:9826-9838. [PMID: 30088924 DOI: 10.1021/acs.inorgchem.8b00489] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Knowledge of the nature of exchangeable (labile) intracellular Zn(II) is increasingly important for biomedical research. The detection and quantitative determination of Zn(II) ions is usually performed by using Zn(II)-specific fluorescent sensors, among which 2-[2-[2-[2-[bis(carboxylatomethyl)amino]-5-methoxyphenoxy]ethoxy]-4-(2,7-difluoro-3-oxido-6-oxo-4a,9a-dihydroxanthen-9-yl)anilino]acetate (FluoZin-3) has been used most widely. Selectivity of this sensor for Zn(II) over other divalent cations was demonstrated, but possible interference in its performance by other compounds has not been investigated. Many potential low molecular weight ligands for Zn(II) ions (LMWLs) are abundant in the cell. In this study we demonstrate that FluoZin-3 is susceptible to competition for Zn(II) from LMWLs and also forms strong ternary complexes with some of them. We determined the set of conditional stability constants C Ktern for ternary Zn(FluoZin-3)(LMWL) complexes using fluorescence titrations and applied it to model the response of exchangeable zinc to FluoZin-3. We found that competition and formation of ternary complexes with LMWLs together strongly affect (net reduce) the Zn(FluoZin-3) fluorescence. This effect may cause a significant underestimation of exchangeable Zn(II). We also demonstrated a strong pH dependence of this effect. Reduced glutathione (GSH) emerged as the most important Zn(II) partner among the LMWLs, characterized with Ktern = 2.8 ± 0.2 × 106 M-1. Our experiments and calculations suggest that Zn(LMWL) complexes contribute to the exchangeable cellular zinc pool.
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Affiliation(s)
- Ilona Marszałek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Goch
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland.,Faculty of Pharmacy , Medical University of Warsaw , Banacha 1 , 02-091 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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6
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Quinta-Ferreira ME, Sampaio Dos Aidos FDS, Matias CM, Mendes PJ, Dionísio JC, Santos RM, Rosário LM, Quinta-Ferreira RM. Modelling zinc changes at the hippocampal mossy fiber synaptic cleft. J Comput Neurosci 2016; 41:323-337. [PMID: 27696002 DOI: 10.1007/s10827-016-0620-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/11/2016] [Accepted: 08/15/2016] [Indexed: 01/18/2023]
Abstract
Zinc, a transition metal existing in very high concentrations in the hippocampal mossy fibers from CA3 area, is assumed to be co-released with glutamate and to have a neuromodulatory role at the corresponding synapses. The synaptic action of zinc is determined both by the spatiotemporal characteristics of the zinc release process and by the kinetics of zinc binding to sites located in the cleft area, as well as by their concentrations. This work addresses total, free and complexed zinc concentration changes, in an individual synaptic cleft, following single, short and long periods of evoked zinc release. The results estimate the magnitude and time course of the concentrations of zinc complexes, assuming that the dynamics of the release processes are similar to those of glutamate. It is also considered that, for the cleft zinc concentrations used in the model (≤ 1 μM), there is no postsynaptic zinc entry. For this reason, all released zinc ends up being reuptaken in a process that is several orders of magnitude slower than that of release and has thus a much smaller amplitude. The time derivative of the total zinc concentration in the cleft is represented by the difference between two alpha functions, corresponding to the released and uptaken components. These include specific parameters that were chosen assuming zinc and glutamate co-release, with similar time courses. The peak amplitudes of free zinc in the cleft were selected based on previously reported experimental cleft zinc concentration changes evoked by single and multiple stimulation protocols. The results suggest that following a low amount of zinc release, similar to that associated with one or a few stimuli, zinc clearance is mainly mediated by zinc binding to the high-affinity sites on the NMDA receptors and to the low-affinity sites on the highly abundant GLAST glutamate transporters. In the case of higher zinc release brought about by a larger group of stimuli, most zinc binding occurs essentially to the GLAST transporters, having the corresponding zinc complex a maximum concentration that is more than one order of magnitude larger than that for the high and low affinity NMDA sites. The other zinc complexes considered in the model, namely those formed with sites on the AMPA receptors, calcium and KATP channels and with ATP molecules, have much smaller contributions to the synaptic zinc clearance.
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Affiliation(s)
- M E Quinta-Ferreira
- CNC- Center for Neuroscience and Cell Biology, University of Coimbra, P-3004-504, Coimbra, Portugal.
- Department of Physics, University of Coimbra, P-3004-516, Coimbra, Portugal.
| | - F D S Sampaio Dos Aidos
- CNC- Center for Neuroscience and Cell Biology, University of Coimbra, P-3004-504, Coimbra, Portugal
- Department of Physics, University of Coimbra, P-3004-516, Coimbra, Portugal
- CFisUC, Department of Physics, University of Coimbra, P-3004-516, Coimbra, Portugal
| | - C M Matias
- CNC- Center for Neuroscience and Cell Biology, University of Coimbra, P-3004-504, Coimbra, Portugal
- UTAD- University of Trás-os-montes and Alto Douro, P-5000-801, Vila Real, Portugal
| | - P J Mendes
- Department of Physics, University of Coimbra, P-3004-516, Coimbra, Portugal
- LIP- Laboratory of Instrumentation and Experimental Particles Physics, P-3004-516, Coimbra, Portugal
| | - J C Dionísio
- CNC- Center for Neuroscience and Cell Biology, University of Coimbra, P-3004-504, Coimbra, Portugal
- Department of Animal Biology, University of Lisbon, P-1749-016, Lisbon, Portugal
| | - R M Santos
- CNC- Center for Neuroscience and Cell Biology, University of Coimbra, P-3004-504, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, P-3004-516, Coimbra, Portugal
| | - L M Rosário
- CNC- Center for Neuroscience and Cell Biology, University of Coimbra, P-3004-504, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, P-3004-516, Coimbra, Portugal
| | - R M Quinta-Ferreira
- CIEPQPF - Research Centre of Chemical Process Engineering and Forest Products, Department of Chemical Engineering, University of Coimbra, P-3030-790, Coimbra, Portugal
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7
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Sharma RK, Maurya A, Rajamani P, Mehata MS, Kumar A. meta-Benziporphodimethenes: New Cell-Imaging Porphyrin Analogue Molecules. ChemistrySelect 2016. [DOI: 10.1002/slct.201600812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Ravi Kumar Sharma
- Department of Applied Chemistry; Delhi Technological University; Bawana Road Delhi-42 India
| | - Anurag Maurya
- School of Environmental Sciences; Jawaharlal Nehru University; Delhi-67 India
| | - Paulraj Rajamani
- School of Environmental Sciences; Jawaharlal Nehru University; Delhi-67 India
| | - Mohan Singh Mehata
- Department of Applied Physics; Delhi Technological University; Bawana Road Delhi-42 India
| | - Anil Kumar
- Department of Applied Chemistry; Delhi Technological University; Bawana Road Delhi-42 India
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8
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Hara H, Taniguchi M, Kobayashi M, Kamiya T, Adachi T. Plasma-activated medium-induced intracellular zinc liberation causes death of SH-SY5Y cells. Arch Biochem Biophys 2015; 584:51-60. [DOI: 10.1016/j.abb.2015.08.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/21/2015] [Accepted: 08/23/2015] [Indexed: 01/29/2023]
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9
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Goswami S, Maity S, Maity AC, Das AK, Khanra K, Mandal TK, Bhattacharyya N. A macrocyclic piperazine linked extremely Zn2+ selective fluorescent chemosensor with bio-imaging and for H2PO4− sensing. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Safin DA, Babashkina MG, Garcia Y. Crown ether-containing Schiff base as a highly efficient "turn-on" fluorescent sensor for determination and separation of Zn2+ in water. Dalton Trans 2013; 42:1969-72. [PMID: 23235741 DOI: 10.1039/c2dt32445h] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A highly efficient Zn(2+) "turn-on" fluorescent sensor, [4'-benzo-15-crown-5]N=CH-(2-OH-C(6)H(4)) (HL), has been synthesized. In the presence of Zn(NO(3))(2), displays high selectivity and sensitive enhancement of fluorescence intensity in water with the formation of [ZnL(2)]. Addition of an equimolar amount of KNO(3) to [ZnL(2)] leads to the formation of {[KZnL(2)]NO(3)}(n).
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Affiliation(s)
- Damir A Safin
- Institute of Condensed Matter and Nanosciences, MOST - Inorganic Chemistry, Université Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve, Belgium.
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11
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Hawkins BE, Frederickson CJ, Dewitt DS, Prough DS. Fluorophilia: fluorophore-containing compounds adhere non-specifically to injured neurons. Brain Res 2011; 1432:28-35. [PMID: 22137653 DOI: 10.1016/j.brainres.2011.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/02/2011] [Accepted: 11/03/2011] [Indexed: 11/18/2022]
Abstract
Ionic (free) zinc (Zn(2+)) is implicated in apoptotic neuronal degeneration and death. In our attempt to examine the effects of Zn(2+) in neurodegeneration following brain injury, we serendipitously discovered that injured neurons bind fluorescein moieties, either alone or as part of an indicator dye, in histologic sections. This phenomenon, that we have termed "fluorophilia", is analogous to the ability of degenerating neuronal somata and axons to bind silver ions (argyrophilia - the basis of silver degeneration stains). To provide evidence that fluorophilia occurs in sections of brain tissue, we used a wide variety of indicators such as Fluoro-Jade (FJ), a slightly modified fluorescein sold as a marker for degenerating neurons; Newport Green, a fluorescein-containing Zn(2+) probe; Rhod-5N, a rhodamine-containing Ca(2+) probe; and plain fluorescein. All yielded remarkably similar staining of degenerating neurons in the traumatic brain-injured tissue with the absence of staining in our sham-injured brains. Staining of presumptive injured neurons by these agents was not modified when Zn(2+) in the brain section was removed by prior chelation with EDTA or TPEN, whereas staining by a non-fluorescein containing Zn(2+) probe, N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide (TSQ), was suppressed by prior chelation. Thus, certain fluorophore-containing compounds nonspecifically stain degenerating neuronal tissue in histologic sections and may not reflect the presence of Zn(2+). This may be of concern to researchers using indicator dyes to detect metals in brain tissue sections. Further experiments may be advised to clarify whether Zn(2+)-binding dyes bind more specifically in intact neurons in culture or organotypic slices.
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Affiliation(s)
- Bridget E Hawkins
- Charles R. Allen Research Laboratories, Department of Anesthesiology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-1102, USA.
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12
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Ballestín R, Molowny A, Marín MP, Esteban-Pretel G, Romero AM, Lopez-Garcia C, Renau-Piqueras J, Ponsoda X. Ethanol reduces zincosome formation in cultured astrocytes. Alcohol Alcohol 2010; 46:17-25. [PMID: 21123366 DOI: 10.1093/alcalc/agq079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Zinc is an ion that participates in basic cellular and tissular functions. Zinc deficiency is present in many physiological and health problems affecting most body organs, including the brain. Among the circumstances involved in zinc deficiency, ethanol consumption is probably one of the most frequent. A dietary zinc supplement has been proposed as possibly being an efficient method to palliate zinc deficiency. Astrocytes form part of the hematoencephalic barrier, and they are apparently implicated in the homeostasis of the neuronal medium. In this work, we analyze the effect of ethanol on extracellular zinc management by rat astrocytes in culture. METHODS Intracellular levels of 'free zinc ions', in controls and 30 mM ethanol-treated astrocytes, were visualized by using the zinc fluorochrome TSQ. Cytoplasmic fluorescence and zincosome formation were measured after adding extracellular 50 µM ZnSO(4) to cell monolayers. Zincosomes were also observed at the electron microscopy level. RESULTS Exposure to ethanol for 7 days lowered the basal zinc levels of astrocytes by ∼30%. This difference was consistently maintained after the zinc pulse. Zinc ions were confined to bright fluorescent particles, the 'zincosomes', which appeared to be formed by the endocytic pathway. Zincosomes were less abundant in alcohol-treated cells, indicating a deficit in endocytoses as the origin of low zinc intake in astrocytes after ethanol treatment. CONCLUSIONS Ethanol reduces both intracellular ionic zinc levels and extracellular zinc uptake, resulting in poorer zincosome formation. Given the endocytic nature of zincosomes, the effect of ethanol on membrane trafficking is apparently the origin of this deficit.
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Affiliation(s)
- Raúl Ballestín
- 1Biologia Cellular, Universitat de València, Avda. Dr. Moliner 50, 46100 Burjassot, Spain
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13
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Winters MS, Chan Q, Caruso JA, Deepe GS. Metallomic analysis of macrophages infected with Histoplasma capsulatum reveals a fundamental role for zinc in host defenses. J Infect Dis 2010; 202:1136-45. [PMID: 20731582 DOI: 10.1086/656191] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The fungal pathogen Histoplasma capsulatum evades the innate and adaptive immune responses and thrives within resting macrophages. Cytokines that induce antimicrobial activity, such as granulocyte macrophage colony-stimulating factor (GM-CSF), inhibit H. capsulatum growth in macrophages. Conversely, interleukin 4 inhibits the killing of intracellular pathogens. Using inductively coupled plasma mass spectrometry, we examined alterations in the metal homeostasis of murine H. capsulatum-infected macrophages that were exposed to activating cytokines. Decreases in the levels of iron (Fe(2+) and Fe(3+)) and zinc (Zn(2+)) were observed in infected, GM-CSF-treated macrophages compared with those in infected controls. Interleukin 4 reversed the antifungal activity of GM-CSF-activated macrophages and was associated with increased intracellular Zn(2+) levels. Chelation of Zn(2+) inhibited yeast replication in both the absence of macrophages and the presence of macrophages. Treatment of cells with GM-CSF altered the host Zn(2+) binding species profile. These results establish that Zn(2+) deprivation may be a host defense mechanism utilized by macrophages.
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Affiliation(s)
- Michael S Winters
- Division of Infectious Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0560, USA.
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14
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Abstract
In the past decade, fluorescent chemosensors for zinc ion (Zn(2+)) have attracted great attention because of the biological significance of zinc combined with the simplicity and high sensitivity of fluorescence assays. Chemosensors can be divided into a fluorophore, a spacer and a receptor unit; the receptor is the central processing unit (CPU) of a chemosensor. This tutorial review will classify zinc chemosensors based on receptor types.
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Affiliation(s)
- Zhaochao Xu
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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15
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Colvin RA, Holmes WR, Fontaine CP, Maret W. Cytosolic zinc buffering and muffling: their role in intracellular zinc homeostasis. Metallomics 2010; 2:306-17. [PMID: 21069178 DOI: 10.1039/b926662c] [Citation(s) in RCA: 307] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Our knowledge of the molecular mechanisms of intracellular homeostatic control of zinc ions is now firmly grounded on experimental findings gleaned from the study of zinc proteomes and metallomes, zinc transporters, and insights from the use of computational approaches. A cell's repertoire of zinc homeostatic molecules includes cytosolic zinc-binding proteins, transporters localized to cytoplasmic and organellar membranes, and sensors of cytoplasmic free zinc ions. Under steady state conditions, a primary function of cytosolic zinc-binding proteins is to buffer the relatively large zinc content found in most cells to a cytosolic zinc(ii) ion concentration in the picomolar range. Under non-steady state conditions, zinc-binding proteins and transporters act in concert to modulate transient changes in cytosolic zinc ion concentration in a process that is called zinc muffling. For example, if a cell is challenged by an influx of zinc ions, muffling reactions will dampen the resulting rise in cytosolic zinc ion concentration and eventually restore the cytosolic zinc ion concentration to its original value by shuttling zinc ions into subcellular stores or by removing zinc ions from the cell. In addition, muffling reactions provide a potential means to control changes in cytosolic zinc ion concentrations for purposes of cell signalling in what would otherwise be considered a buffered environment not conducive for signalling. Such intracellular zinc ion signals are known to derive from redox modifications of zinc-thiolate coordination environments, release from subcellular zinc stores, and zinc ion influx via channels. Recently, it has been discovered that metallothionein binds its seven zinc ions with different affinities. This property makes metallothionein particularly well positioned to participate in zinc buffering and muffling reactions. In addition, it is well established that metallothionein is a source of zinc ions under conditions of redox signalling. We suggest that the biological functions of transient changes in cytosolic zinc ion concentrations (presumptive zinc signals) complement those of calcium ions in both spatial and temporal dimensions.
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Affiliation(s)
- Robert A Colvin
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
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16
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Trapani V, Farruggia G, Marraccini C, Iotti S, Cittadini A, Wolf FI. Intracellular magnesium detection: imaging a brighter future. Analyst 2010; 135:1855-66. [DOI: 10.1039/c0an00087f] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Ohana E, Hoch E, Keasar C, Kambe T, Yifrach O, Hershfinkel M, Sekler I. Identification of the Zn2+ binding site and mode of operation of a mammalian Zn2+ transporter. J Biol Chem 2009; 284:17677-86. [PMID: 19366695 DOI: 10.1074/jbc.m109.007203] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vesicular zinc transporters (ZnTs) play a critical role in regulating Zn2+ homeostasis in various cellular compartments and are linked to major diseases ranging from Alzheimer disease to diabetes. Despite their importance, the intracellular localization of ZnTs poses a major challenge for establishing the mechanisms by which they function and the identity of their ion binding sites. Here, we combine fluorescence-based functional analysis and structural modeling aimed at elucidating these functional aspects. Expression of ZnT5 was followed by both accelerated removal of Zn2+ from the cytoplasm and its increased vesicular sequestration. Further, activity of this zinc transport was coupled to alkalinization of the trans-Golgi network. Finally, structural modeling of ZnT5, based on the x-ray structure of the bacterial metal transporter YiiP, identified four residues that can potentially form the zinc binding site on ZnT5. Consistent with this model, replacement of these residues, Asp599 and His451, with alanine was sufficient to block Zn2+ transport. These findings indicate, for the first time, that Zn2+ transport mediated by a mammalian ZnT is catalyzed by H+/Zn2+ exchange and identify the zinc binding site of ZnT proteins essential for zinc transport.
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Affiliation(s)
- Ehud Ohana
- Department of Physiology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
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18
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Vašák M, Meloni G. Metallothionein-3, Zinc, and Copper in the Central Nervous System. METALLOTHIONEINS AND RELATED CHELATORS 2009. [DOI: 10.1039/9781847559531-00319] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Metallothionein-3 (MT-3), also known as the neuronal growth inhibitory factor, has been discovered by Uchida and coworkers in 1991 in their search for a cellular component responsible for antagonizing aberrant neuritic sprouting and increased survival of cultured neurons stimulated by Alzheimer's disease (AD) brain extract. Since this initial discovery further studies showed that MT-3 possesses peculiar structural and functional properties not shared by other members of the mammalian MT family. Several lines of evidence suggest that the metal-binding protein MT-3 plays a vital role in zinc and copper homeostasis in the brain. Although far from being understood, the unusual structural properties of MT-3 are responsible for its neuronal growth inhibitory activity, involvement in trafficking of zinc vesicles in the central nervous system, protection against copper-mediated toxicity in AD and in controlling abnormal metal-protein interactions in other neurodegenerative disorders.
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Affiliation(s)
- Milan Vašák
- Institute of Biochemistry, University of Zürich Winterthurerstrasse 190 CH-8057 Zürich Switzerland
| | - Gabriele Meloni
- Institute of Biochemistry, University of Zürich Winterthurerstrasse 190 CH-8057 Zürich Switzerland
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Suh SW. Detection of zinc translocation into apical dendrite of CA1 pyramidal neuron after electrical stimulation. J Neurosci Methods 2008; 177:1-13. [PMID: 18929598 DOI: 10.1016/j.jneumeth.2008.09.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 09/08/2008] [Accepted: 09/09/2008] [Indexed: 11/19/2022]
Abstract
Translocation of the endogenous cation zinc from presynaptic terminals to postsynaptic neurons after brain insult has been implicated as a potential neurotoxic event. Several studies have previously demonstrated that a brief electrical stimulation is sufficient to induce the translocation of zinc from presynaptic vesicles into the cytoplasm (soma) of postsynaptic neurons. In the present work I have extended those findings in three ways: (i) providing evidence that zinc translocation occurs into apical dendrites, (ii) presenting data that there is an apparent translocation into apical dendrites when only a zinc-containing synaptic input is stimulated, and (iii) presenting data that there is no zinc translocation into apical dendrite of ZnT3 KO mice following electrical stimulation. Hippocampal slices were preloaded with the "trappable" zinc fluorescent probe, Newport Green. After washout, a single apical dendrite in the stratum radiatum of hippocampal CA1 area was selected and focused on. Burst stimulation (100Hz, 500microA, 0.2ms, monopolar) was delivered to either the adjacent Schaffer-collateral inputs (zinc-containing) or to the adjacent temporo-ammonic inputs (zinc-free) to the CA1 dendrites. Stimulation of the Schaffer collaterals increased the dendritic fluorescence, which was blocked by TTX, low-Ca medium, or the extracellular zinc chelator, CaEDTA. Stimulation of the temporo-ammonic pathway caused no significant rise in the fluorescence. Genetic depletion of vesicular zinc by ZnT3 KO showed no stimulation-induced apical dendrite zinc rise. The present study provides evidence that synaptically released zinc translocates into postsynaptic neurons through the apical dendrites of CA1 pyramidal neurons during physiological synaptic activity.
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Affiliation(s)
- Sang Won Suh
- Department of Neurology, University of California, San Francisco and Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
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20
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Dineley KE, Devinney MJ, Zeak JA, Rintoul GL, Reynolds IJ. Glutamate mobilizes [Zn2+] through Ca2+ -dependent reactive oxygen species accumulation. J Neurochem 2008; 106:2184-93. [PMID: 18624907 DOI: 10.1111/j.1471-4159.2008.05536.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Liberation of zinc from intracellular stores contributes to oxidant-induced neuronal injury. However, little is known regarding how endogenous oxidant systems regulate intracellular free zinc ([Zn(2+)](i)). Here we simultaneously imaged [Ca(2+)](i) and [Zn(2+)](i) to study acute [Zn(2+)](i) changes in cultured rat forebrain neurons after glutamate receptor activation. Neurons were loaded with fura-2FF and FluoZin-3 to follow [Ca(2+)](i) and [Zn(2+)](i), respectively. Neurons treated with glutamate (100 microM) for 10 min gave large Ca(2+) responses that did not recover after termination of the glutamate stimulus. Glutamate also increased [Zn(2+)](i), however glutamate-induced [Zn(2+)](i) changes were completely dependent on Ca(2+) entry, appeared to arise entirely from internal stores, and were substantially reduced by co-application of the membrane-permeant chelator TPEN during the glutamate treatment. Pharmacological maneuvers revealed that a number of endogenous oxidant producing systems, including nitric oxide synthase, phospholipase A(2), and mitochondria all contributed to glutamate-induced [Zn(2+)](i) changes. We found no evidence that mitochondria buffered [Zn(2+)](i) during acute glutamate receptor activation. We conclude that glutamate-induced [Zn(2+)](i) transients are caused in part by [Ca(2+)](i)-induced reactive oxygen species that arises from both cytosolic and mitochondrial sources.
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Affiliation(s)
- Kirk E Dineley
- Department of Biology, Francis Marion University, Florence, SC, USA
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21
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A novel method for the detection of viable human pancreatic beta cells by flow cytometry using fluorophores that selectively detect labile zinc, mitochondrial membrane potential and protein thiols. Cytometry A 2008; 73:615-25. [DOI: 10.1002/cyto.a.20560] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Mashraqui SH, Sundaram S, Khan T, Bhasikuttan A. Zn2+ selective luminescent ‘off–on’ probes derived from diaryl oxadiazole and aza-15-crown-5. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.08.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Gong HY, Zheng QY, Zhang XH, Wang DX, Wang MX. Methylazacalix[4]pyridine: En Route to Zn2+-Specific Fluoresence Sensors. Org Lett 2006; 8:4895-8. [PMID: 17020330 DOI: 10.1021/ol061928k] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structure: see text] Owing to the electronic nature of the bridging nitrogen atoms which can adopt different hybridizations and form various conjugations with the adjacent pyridine(s), methylazacalix[4]pyridine underwent conformation and cavity preorganization to highly selectively bind the Zn(2+) ion. Rigidification and coplanarity of the macrocyclic ring led to a great enhancement of fluorescence of the intrinsic fluorescent host molecule.
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Affiliation(s)
- Han-Yuan Gong
- Beijing National Laboratory for Molecular Sciences, Laboratory of Chemical Biology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
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24
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Bozym RA, Thompson RB, Stoddard AK, Fierke CA. Measuring picomolar intracellular exchangeable zinc in PC-12 cells using a ratiometric fluorescence biosensor. ACS Chem Biol 2006; 1:103-11. [PMID: 17163650 DOI: 10.1021/cb500043a] [Citation(s) in RCA: 187] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Zinc plays both physiological and pathological roles in biology, making it of increasing interest. To date, intracellular free zinc has been measured in cell types supplemented with or enriched in zinc, such as hippocampal neurons. Here we quantitatively image intracellular exchangeable zinc in an ordinary resting cell culture line (PC-12), using an excitation ratiometric fluorescent biosensor based on carbonic anhydrase (CA). Human CA II has a K d of 4 pM for zinc and suffers no interference from millimolar calcium or magnesium ions. The CA-based biosensor was readily introduced into the cell by a novel approach: fusing a transactivator of transcription (TAT)-derived cell penetrating peptide to the CA molecule and adding it to the cells. Our results indicate that the resting concentration is approximately 5-10 pM in cytoplasm and nucleus. Interestingly, the tetrakis(2-pyridylmethyl)ethylenediamine (TPEN)-Zn complex and TPEN are both apoptogenic for this cell line.
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Affiliation(s)
- Rebecca A Bozym
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, Maryland 21201, USA
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25
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Nolan EM, Jaworski J, Okamoto KI, Hayashi Y, Sheng M, Lippard SJ. QZ1 and QZ2: rapid, reversible quinoline-derivatized fluoresceins for sensing biological Zn(II). J Am Chem Soc 2006; 127:16812-23. [PMID: 16316228 PMCID: PMC1851667 DOI: 10.1021/ja052184t] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
QZ1, 2-[2-chloro-6-hydroxy-3-oxo-5-(quinolin-8-ylaminomethyl)-3H-xanthen-9-yl]benzoic acid, and QZ2, 2-[6-hydroxy-3-oxo-4,5-bis-(quinolin-8-ylaminomethyl)-3H-xanthen-9-yl]benzoic acid, two fluorescein-based dyes derivatized with 8-aminoquinoline, have been prepared and their photophysical, thermodynamic, and zinc-binding kinetic properties determined. Because of their low background fluorescence and highly emissive Zn(II) complexes, QZ1 and QZ2 have a large dynamic range, with approximately 42- and approximately 150-fold fluorescence enhancements upon Zn(II) coordination, respectively. These dyes have micromolar K(d) values for Zn(II) and are selective for Zn(II) over biologically relevant concentrations of the alkali and alkaline earth metals. The Zn(II) complexes also fluoresce brightly in the presence of excess Mn(II), Fe(II), Co(II), Cd(II), and Hg(II), offering improved specificity for Zn(II) over di(2-picolyl)amine-based Zn(II) sensors. Stopped-flow kinetic investigations indicate that QZ1 and QZ2 bind Zn(II) with k(on) values of (3-4) x 10(6) M(-1) s(-1), compared to (6-8) x 10(5) M(-1) s(-1) for select ZP (Zinpyr) dyes, at 4.3 degrees C. Dissociation of Zn(II) from QZ1 and QZ2 occurs with k(off) values of 150 and 160 s(-1), over 5 orders of magnitude larger than those for ZP probes, achieving reversibility on the biological (millisecond) time scale. Laser scanning confocal and two-photon microscopy studies reveal that QZ2 is cell-permeable and Zn(II)-responsive in vivo. Because of its weaker affinity for Zn(II), QZ2 responds to higher concentrations of intracellular Zn(II) than members of the ZP family, illustrating that binding affinity is an important parameter for Zn(II) detection in vivo.
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Affiliation(s)
- Elizabeth M Nolan
- Department of Chemistry, Cambridge, Massachusetts Institute of Technology, 02139, USA
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26
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Tang B, Huang H, Xu K, Tong L, Yang G, Liu X, An L. Highly sensitive and selective near-infrared fluorescent probe for zinc and its application to macrophage cells. Chem Commun (Camb) 2006:3609-11. [PMID: 17047780 DOI: 10.1039/b606809j] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new highly sensitive and selective near-infrared fluorescent probe for zinc ion, based on photoinduced electron transfer (PET) mechanism, has been designed, synthesized, and applied to macrophage cells.
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Affiliation(s)
- Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, China.
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27
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Varea E, Alonso-Llosà G, Molowny A, Lopez-Garcia C, Ponsoda X. Capture of extracellular zinc ions by astrocytes. Glia 2006; 54:304-15. [PMID: 16856150 DOI: 10.1002/glia.20382] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Synaptic zinc ions released during synaptic transmission interact with pre- and postsynaptic neuroreceptors, thus modulating neurotransmission. It is likely that they have to be efficiently cleared from the extracellular milieu to assure subsequent synaptic events. Both neurons and glia are assumed to participate in this clearance by mechanisms that are not fully understood. In this study, electron microscopic zinc cytochemistry has shown zinc-electrondense particles associated with hippocampal astrocytic membranes frequently found accumulated in stacked lamellae. In cultured astrocytes, the use of zinc fluorochromes and endocytic markers allowed the simultaneous imaging of the capture of extracellular zinc simultaneously to plasma membrane markers; this endocytic process was inhibited by high sucrose concentrations. Finally, electron microscopy of zinc-loaded and fluorochrome photoconverted cells demonstrated some early events of extracellular zinc capture as well as its late accumulation in lysosome-like organelles.
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Affiliation(s)
- Emilio Varea
- Cell Biology Department, Universitat de Valencia, Valencia, Spain
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28
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Devinney MJ, Reynolds IJ, Dineley KE. Simultaneous detection of intracellular free calcium and zinc using fura-2FF and FluoZin-3. Cell Calcium 2005; 37:225-32. [PMID: 15670869 DOI: 10.1016/j.ceca.2004.10.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2004] [Revised: 10/09/2004] [Accepted: 10/12/2004] [Indexed: 11/27/2022]
Abstract
Elevation of intracellular free zinc ([Zn2+]i) probably contributes to cell death in injury paradigms involving calcium deregulation and oxidative stress such as glutamate excitotoxicity. However, it is difficult to monitor both ions simultaneously in live cells. Here we present a new method using fluorescence microscopy and the ion sensitive indicators fura-2FF and FluoZin-3 to monitor both [Ca2+]i and [Zn2+]i in primary cortical neurons. We show that the new single wavelength dye FluoZin-3 responds robustly to small zinc loads, is insensitive to high Ca2+ or Mg2+, and is relatively unaffected by low pH or oxidants. The ratiometric indicator fura-2FF is sensitive to both Ca2+ and Zn2+. However, in conditions analogous to excitotoxic glutamate exposure where [Ca2+]i is high relative to [Zn2+]i, we found that fura-2FF responds mostly to [Ca2+]i but is relatively unaffected by low [Zn2+]i. Moreover, fura-2FF ratio changes caused by high [Ca2+]i or high [Zn2+]i could be distinguished because each ion produces a different spectral response. Finally, dual dye experiments showed that FluoZin-3 and fura-2FF respond robustly to [Zn2+]i and [Ca2+]j, respectively, in the same neurons during intense glutamate exposure. These studies provide a novel method for the simultaneous detection of both calcium and zinc in cells.
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Affiliation(s)
- Michael J Devinney
- Department of Pharmacology, University of Pittsburgh School of Medicine, W1351 BST, Pittsburgh, PA 15261, USA
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30
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Quinta-Ferreira ME, Matias CM, Arif M, Dionísio JC. Measurement of presynaptic zinc changes in hippocampal mossy fibers. Brain Res 2004; 1026:1-10. [PMID: 15476692 DOI: 10.1016/j.brainres.2004.07.054] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2004] [Indexed: 11/17/2022]
Abstract
The hippocampal mossy fiber terminals of CA3 area contain high levels of vesicular zinc that is released in a calcium-dependent way, following high-frequency stimulation. However the properties of zinc release during normal synaptic transmission, paired-pulse facilitation and mossy fiber long-term potentiation are still unknown. Using the fluorescent zinc probe N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide, we measured fast mossy fiber zinc changes indicating that zinc is released following single and low levels of electrical stimulation. The observed presynaptic zinc signals are maintained during the expression of mossy fiber long-term potentiation, assumed to be mediated by an increase in transmitter release, and are enhanced during paired-pulse facilitation. This zinc enhancement is, like paired-pulse facilitation, reduced during established long-term potentiation. The correlation between the paired-pulse evoked zinc and field potential responses supports the idea that zinc is co-released with glutamate.
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Affiliation(s)
- M E Quinta-Ferreira
- Department of Physics and Center for Neurosciences of Coimbra, University of Coimbra, 3004-516 Coimbra, Portugal.
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31
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Abstract
Although the presence of Zn2+ in the brain has been known for nearly half a century, only recently has its precise location and potential roles as a neuromodulator and signaling molecule as well as neurotoxic agent come to the forefront. Unfortunately, our understanding of Zn2+ homeostatic mechanisms lags far behind. The recent identification of presumed Zn2+ transporters has opened new approaches to studying Zn2+ homeostatic mechanisms in neurons. Zn2+ transporters are involved in separate Zn2+ influx and efflux pathways in neurons. However, we are only beginning to understand the mechanism of Zn2+ transport and much more research needs to be done. We are only beginning to understand the transcriptional control and cellular location of Zn2+ transporters, as well. Finally, this review presents a working model of neuronal Zn2+ homeostasis and discusses the experimental evidence for the proposed roles that Zn2+ transporters might play.
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Affiliation(s)
- Robert A Colvin
- Program in Neuroscience, Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
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32
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Ohana E, Segal D, Palty R, Ton-That D, Moran A, Sensi SL, Weiss JH, Hershfinkel M, Sekler I. A Sodium Zinc Exchange Mechanism Is Mediating Extrusion of Zinc in Mammalian Cells. J Biol Chem 2004; 279:4278-84. [PMID: 14581475 DOI: 10.1074/jbc.m309229200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Zinc influx, driven by a steep inward electrochemical gradient, plays a fundamental role in zinc signaling and in pathophysiologies linked to intracellular accumulation of toxic zinc. Yet, the cellular transport mechanisms that actively generate or maintain the transmembrane gradients are not well understood. We monitored Na+-dependent Zn2+ transport in HEK293 cells and cortical neurons, using fluorescent imaging. Treatment of the HEK293 cells with CaPO4 precipitates induced Na+-dependent Zn2+ extrusion, against a 500-fold transmembrane zinc gradient, or zinc influx upon reversal of Na+ gradient, thus indicating that Na+/Zn2+ exchange is catalyzing active Zn2+ transport. Depletion of intracellular ATP did not inhibit the Na+-dependent Zn2+ extrusion, consistent with a mechanism involving a secondary active transporter. Inhibitors of the Na+/Ca2+ exchanger failed to inhibit Na+-dependent Zn2+ efflux. In addition, zinc transport was unchanged in HEK293 cells heterologously expressing functional cardiac or neuronal Na+/Ca2+ exchangers, thus indicating that the Na+/Zn2+ exchange activity is not mediated by the Na+/Ca2+ exchanger. Sodium-dependent zinc exchange, facilitating the removal of intracellular zinc, was also monitored in neurons. To our knowledge, the Na+/Zn2+ exchanger described here is the first example of a mammalian transport mechanism capable of Na+-dependent active extrusion of zinc. Such mechanism is likely to play an important role, not only in generating the transmembrane zinc gradients, but also in protecting cells from the potentially toxic effects of permeation of this ion.
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Affiliation(s)
- Ehud Ohana
- Department of Physiology, Faculty of Health Science, Ben Gurion University of the Negev, POB 653, Beer-Sheva 84105, Israel
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Gore A, Moran A, Hershfinkel M, Sekler I. Inhibitory mechanism of store-operated Ca2+ channels by zinc. J Biol Chem 2004; 279:11106-11. [PMID: 14715648 DOI: 10.1074/jbc.m400005200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Capacitative calcium influx plays an important role in shaping the Ca(2+) response of various tissues and cell types. Inhibition by heavy metals is a hallmark of store-operated calcium channel (SOCC) activity. Paradoxically, although zinc is the only potentially physiological relevant ion, it is the least investigated in terms of inhibitory mechanism. In the present study, we characterize the inhibitory mechanism of the SOCC by Zn(2+) in the human salivary cell line, HSY, and rat salivary submandibular ducts and acini by monitoring SOCC activity using fluorescence imaging. Analysis of Zn(2+) inhibition indicated that Zn(2+) acts as a competitive inhibitor of Ca(2+) influx but does not permeate through the SOCC, suggesting that Zn(2+) interacts with an extracellular site of SOCC. Application of the reducing agents, dithiothreitol (DTT) and beta-mercaptoethanol, totally eliminated Zn(2+) and Cd(2+) inhibition of SOCC, suggesting that cysteines are part of the Zn(2+) and Cd(2+) binding site. Interestingly, reducing conditions failed to eliminate the inhibition of SOCC by La(3+) and Gd(3+), indicating that the Zn(2+) and lanthanides binding sites are distinct. Finally, we show that changes in redox potential and Zn(2+) are regulating, via SOCC activity, the agonist-induced Ca(2+) response in salivary ducts. The presence of a specific Zn(2+) site, responsive to physiological Zn(2+) and redox potential, may not only be instrumental for future structural studies of various SOCC candidates but may also reveal novel physiological aspects of the interaction between zinc, redox potential, and cellular Ca(2+) homeostasis.
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Affiliation(s)
- Ariel Gore
- Physiology and Morphology, Faculty of Health Science and the Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, POB 653, Beer-Sheva, 84105, Israel
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34
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Jiang P, Guo Z. Fluorescent detection of zinc in biological systems: recent development on the design of chemosensors and biosensors. Coord Chem Rev 2004. [DOI: 10.1016/j.cct.2003.10.013] [Citation(s) in RCA: 739] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lin AMY, Fan SF, Yang DM, Hsu LL, Yang CHJ. Zinc-induced apoptosis in substantia nigra of rat brain: neuroprotection by vitamin D3. Free Radic Biol Med 2003; 34:1416-25. [PMID: 12757852 DOI: 10.1016/s0891-5849(03)00105-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Accumulation of transition metals has been suggested to be responsible for the deteriorated nigrostriatal dopaminergic system in Parkinson's patients. In the present study, the mechanism underlying the zinc-induced neurotoxicity was investigated in the nigrostriatal dopaminergic system in vivo. Our 6-methoxy-8-paratoluene sulfonamide quinoline fluorescence study showed zinc translocation in the infused nigral cells after intranigral infusion of zinc. Furthermore, lipid peroxidation in the zinc-infused substantia nigra was consistently elevated 4 h to 7 d after the infusion. At the same time, an abrupt increase in cytosolic cytochrome c content in the infused substantia nigra was observed 4 h after zinc infusion and gradually decreased to basal levels 7 d after infusion. Both TUNEL-positive neurons and DNA fragmentation, indicatives of apoptosis, were detected in the zinc-infused substantia nigra. Furthermore, striatal dopamine content was reduced 7 d after the infusion. In attempt to prevent zinc-induced neurotoxicity, vitamin D3 was systemically administered. Zinc-induced increases in lipid peroxidation and cytosolic cytochrome c in the infused substantia nigra were prevented by this treatment. Moreover, zinc-induced reduction in striatal dopamine content was attenuated after vitamin D3 treatment. Our in vivo data suggest that zinc-induced oxidative stress may result in apoptosis followed by reduced dopaminergic function in the nigrostriatal dopaminergic system. Furthermore, vitamin D3 prevented zinc-induced oxidative injuries in the rat brain.
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Affiliation(s)
- Anya M Y Lin
- Department of Medical Research and Education, Veterans General Hospital-Taipei, Taipei, Taiwan
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36
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Abstract
Metalloneurochemistry is the study of metal ion function in the brain and nervous system at the molecular level. Research in this area is exemplified through discussion of several forefront areas where significant progress has been made in recent years. The structure and function of ion channels have been elucidated through high-resolution x-ray structural work on the bacterial K(+) ion channel. Selection of potassium over sodium ions is achieved by taking advantage of key principles of coordination chemistry. The role of calcium ions in neuronal signal transduction is effected by several Ca(2+)-binding protein such as calmodulin, calcineurin, and synaptotagmin. Structural changes in response to calcium ion concentrations allow these proteins to function in memory formation and other neurochemical roles. Metallochaperones help to achieve metal ion homeostasis and thus prevent neurological diseases because of metal ion imbalance. Much detailed chemical information about these systems has become available recently. Zinc is another important metal ion in neuroscience. Its concentration in brain is in part controlled by metallothionein, and zinc is released in the hippocampus at glutamatergic synapses. New fluorescent sensors have become available to help track such zinc release.
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Affiliation(s)
- Shawn C Burdette
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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37
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Thompson RB, Peterson D, Mahoney W, Cramer M, Maliwal BP, Suh SW, Frederickson C, Fierke C, Herman P. Fluorescent zinc indicators for neurobiology. J Neurosci Methods 2002; 118:63-75. [PMID: 12191759 DOI: 10.1016/s0165-0270(02)00144-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mounting evidence indicates that zinc has multiple roles in cell biology, viz. as a part of metalloenzyme catalytic sites, as a structural component of gene regulatory proteins, and (like calcium) as a free signal ion, particularly in the cortex of the brain. While most Zn(II) in the brain is tightly bound, such that free Zn(II) levels extracellularly and intracellularly are likely to be picomolar, a subset of glutamatergic neurons possess weakly bound zinc in presynaptic boutons which is released at micromolar levels in response to a variety of stimuli. Key to further progress in understanding the multiple roles of zinc will be the availability of fluorescent indicator systems that will permit quantitative determination and imaging of zinc fluxes and levels over a broad concentration range both intracellularly and extracellularly using fluorescence microscopy. Towards that end, we have compared a variety of fluorescent indicators for their sensitivity to Zn(II) and Cu(II), selectivity for Zn(II) in the presence of potential interferents such as Ca(II) or Mg(II), and potential for quantitative imaging. The commercially available probes Fura-2, Mag-Fura-5, Newport Green DCF, and FuraZin-1 were compared with the carbonic anhydrase-based indicator systems for selectivity and sensitivity. In addition, intracellular levels of Zn following excitotoxic insult were determined by single pixel fluorescence lifetime microscopy of Newport Green DCF, and extracellular levels of free zinc following stimulus of rat hippocampal slices were determined ratiometrically with a carbonic anhydrase-based indicator system. These results suggest that zinc ion at high nM to microM levels can be accurately quantitated by FuraZin-1 ratiometrically or by Newport Green DCF by fluorescence lifetime; and at levels down to pM by intensity ratio, lifetime, or polarization using carbonic anhydrase-based systems.
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Affiliation(s)
- R B Thompson
- Department of Biochemistry and Molecular Biology and Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201, USA.
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38
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Gee KR, Zhou ZL, Ton-That D, Sensi SL, Weiss JH. Measuring zinc in living cells. A new generation of sensitive and selective fluorescent probes. Cell Calcium 2002; 31:245-51. [PMID: 12098227 DOI: 10.1016/s0143-4160(02)00053-2] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
New fluorescent indicators with nanomolar to micromolar affinities for Zn(2+) have been synthesized in wavelengths from UV to the far red. The UV light-excited indicators are ratiometric. The visible wavelength indicators are non-ratiometric and exhibit large and pH-independent fluorescence increases with increasing zinc concentrations, with little to no sensitivity to physiologically relevant Ca(2+) concentrations. Experiments in neuronal and non-neuronal cell cultures show the new indicators to retain their sensitivity to and selectivity for zinc after conversion to cell-permeable forms.
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Affiliation(s)
- K R Gee
- Molecular Probes, Inc., 4849 Pitchford Avenue, Eugene, OR 97478, USA.
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Lukowiak B, Vandewalle B, Riachy R, Kerr-Conte J, Gmyr V, Belaich S, Lefebvre J, Pattou F. Identification and purification of functional human beta-cells by a new specific zinc-fluorescent probe. J Histochem Cytochem 2001; 49:519-28. [PMID: 11259455 DOI: 10.1177/002215540104900412] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Pancreatic beta-cells contain large amounts of zinc. We took advantage of this to try to localize, quantify, and isolate insulin-producing cells from islet preparations. Our study was designed to identify a non-toxic zinc-sensitive fluorescent probe able to selectively label labile zinc in viable beta-cells and to exhibit excitation and emission wavelengths in the visible spectrum, making this technique exploitable by most instruments. We tested Newport Green, a probe excitable at 485 nm with a dissociation constant in the micromolar range corresponding to a low affinity for zinc. The loading of the lipophilic esterified form of Newport Green was easy, rapid, specific, and non-toxic to cells. Confocal microscopy highlighted an intense fluorescence associated with secretory granules. Regression analyses showed a good relationship between zinc fluorescence and islet number (r = 0.98) and between zinc fluorescence and insulin content (r = 0.81). The determination of Zn fluorescence per DNA enabled us to assess the quality of the different islet preparations intended for islet allografting in terms of both purity and viability. Cell sorting of dissociated Newport Green-labeled cells resulted in a clear separation of beta-cells, as judged by insulin content per DNA and immunocytochemical analysis. This zinc probe, the first able to specifically label living cells in the visible spectrum, appears very promising for beta-cell experimentation, both clinically and for basic research.
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Affiliation(s)
- B Lukowiak
- UPRS 1048/ERIT-M-INSERM, Université de Lille, Lille, France
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Méplan C, Richard MJ, Hainaut P. Metalloregulation of the tumor suppressor protein p53: zinc mediates the renaturation of p53 after exposure to metal chelators in vitro and in intact cells. Oncogene 2000; 19:5227-36. [PMID: 11077439 DOI: 10.1038/sj.onc.1203907] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The tumor suppressor p53 is a transcription factor which binds DNA through a structurally complex domain stabilized by a zinc atom. Zinc chelation disrupts the architecture of this domain, inducing the protein to adopt an immunological phenotype identical to that of many mutant forms of p53. In this report, we used 65Zn to show that incorporation of zinc within the protein was required for folding in the 'wild-type' conformation capable of specific DNA-binding. Using a cellular assay, we show that addition of extracellular zinc at concentrations within the physiological range (5 microM) was required for renaturation and reactivation of wild-type p53. Among other divalent metals tested (Cd2+, Cu2+, Co2+, Fe2+ and Ni2+), only Co2+ at 125 microM had a similar effect. Recombinant metallothionein (MT), a metal chelator protein, was found to modulate p53 conformation in vitro. In cultured cells, overexpression of MT by transfection could modulate p53 transcriptional activity. Taken together, these results suggest that zinc binding plays a regulatory role in the control of p53 folding and DNA-binding activity.
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Affiliation(s)
- C Méplan
- Group of Molecular Carcinogenesis, International Agency for Research on Cancer, 150 cours Albert Thomas, F-69372, Lyon Cedex 08, France
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Aizenman E, Stout AK, Hartnett KA, Dineley KE, McLaughlin B, Reynolds IJ. Induction of neuronal apoptosis by thiol oxidation: putative role of intracellular zinc release. J Neurochem 2000; 75:1878-88. [PMID: 11032877 DOI: 10.1046/j.1471-4159.2000.0751878.x] [Citation(s) in RCA: 314] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis.
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Affiliation(s)
- E Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
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Hyrc KL, Bownik JM, Goldberg MP. Ionic selectivity of low-affinity ratiometric calcium indicators: mag-Fura-2, Fura-2FF and BTC. Cell Calcium 2000; 27:75-86. [PMID: 10756974 DOI: 10.1054/ceca.1999.0092] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Accurate measurement of elevated intracellular calcium levels requires indicators with low calcium affinity and high selectivity. We examined fluorescence spectral properties and ionic specificity of three low-affinity, ratiometric indicators structurally related to Fura-2: mag-Fura-2 (furaptra), Fura-2FF, and BTC. The indicators differed in respect to their excitation wavelengths, affinity for Ca2+ (Kd approximately 20 microM, 6 microM and 12 microM respectively) and selectivity over Mg2+ (Kd approximately 2 mM for mag-Fura-2, > 10 mM for Fura-2FF and BTC). Among the tested indicators, BTC was limited by a modest dynamic range upon Ca2+ binding, susceptibility to photodamage, and sensitivity to alterations in pH. All three indicators bound other metal ions including Zn2+, Cd2+ and Gd3+. Interestingly, only in the case of BTC were spectral differences apparent between Ca2+ and other metal ions. For example, the presence of Zn2+ increased BTC fluorescence 6-fold at the Ca2+ isosbestic point, suggesting that this dye may be used as a fluorescent Zn2+ indicator. Fura-2FF has high specificity, wide dynamic range, and low pH sensitivity, and is an optimal low-affinity Ca2+ indicator for most imaging applications. BTC may be useful if experimental conditions require visible wavelength excitation or sensitivity to other metal ions including Zn2+.
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Affiliation(s)
- K L Hyrc
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
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Abstract
Epidemiological studies have shown a strong relationship between the level of lead in blood and bone as assessed by performance on IQ tests and other psychometric tests. Approximately 1 out of 10 children in the United States have blood lead levels above 10 microg/dl, which has been established as the level of concern. Studies on experimental animals exposed to lead after birth have shown learning deficits at similar blood lead levels. Since learning requires the remodeling of synapses in the brain, lead may specifically affect synaptic transmission. Although the molecular targets for lead are unknown, a vast amount of evidence accumulated over many years has shown that lead disrupts processes that are regulated by calcium. Our laboratory has been studying the effect of lead on protein kinase C, a family of isozymes some of which require calcium for activity. We and others have shown that picomolar concentrations of lead can replace micromolar concentrations of calcium in a protein kinase C enzyme assay. Furthermore, lead activates protein kinase C in intact cells and induces the expression of new genes by a mechanism dependent on protein kinase C. We propose that the learning deficits caused by lead are due to events regulated by protein kinase C that most likely occur at the synapse.
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Affiliation(s)
- J Bressler
- Dept. of Neurology, The Johns Hopkins University School of Public Health and Hygiene and The Kennedy Krieger Research Institute, Baltimore, MD 21205, USA.
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Sensi SL, Yin HZ, Carriedo SG, Rao SS, Weiss JH. Preferential Zn2+ influx through Ca2+-permeable AMPA/kainate channels triggers prolonged mitochondrial superoxide production. Proc Natl Acad Sci U S A 1999; 96:2414-9. [PMID: 10051656 PMCID: PMC26798 DOI: 10.1073/pnas.96.5.2414] [Citation(s) in RCA: 323] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synaptically released Zn2+ can enter and cause injury to postsynaptic neurons. Microfluorimetric studies using the Zn2+-sensitive probe, Newport green, examined levels of [Zn2+]i attained in cultured cortical neurons on exposure to N-methyl-D-asparte, kainate, or high K+ (to activate voltage-sensitive Ca2+ channels) in the presence of 300 microM Zn2+. Indicating particularly high permeability through Ca2+-permeable alpha-amino3-hydroxy-5-methyl-4-isoxazolepropionic-acid/kainate (Ca-A/K) channels, micromolar [Zn2+]i rises were observed only after kainate exposures and only in neurons expressing these channels [Ca-A/K(+) neurons]. Further studies using the oxidation-sensitive dye, hydroethidine, revealed Zn2+-dependent reactive oxygen species (ROS) generation that paralleled the [Zn2+]i rises, with rapid oxidation observed only in the case of Zn2+ entry through Ca-A/K channels. Indicating a mitochondrial source of this ROS generation, hydroethidine oxidation was inhibited by the mitochondrial electron transport blocker, rotenone. Additional evidence for a direct interaction between Zn2+ and mitochondria was provided by the observation that the Zn2+ entry through Ca-A/K channels triggered rapid mitochondrial depolarization, as assessed by using the potential-sensitive dye tetramethylrhodamine ethylester. Whereas Ca2+ influx through Ca-A/K channels also triggers ROS production, the [Zn2+]i rises and subsequent ROS production are of more prolonged duration.
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Affiliation(s)
- S L Sensi
- Department of Neurology, University of California, Irvine, CA 92697-4292, USA
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