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Lange A, Segner H. The Role of Glutathione and Sulfhydryl Groups in Cadmium Uptake by Cultures of the Rainbow Trout RTG-2 Cell Line. Cells 2023; 12:2720. [PMID: 38067148 PMCID: PMC10705847 DOI: 10.3390/cells12232720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
The aim of this study is to investigate the role of cellular sulfhydryl and glutathione (GSH) status in cellular cadmium (Cd) accumulation using cultures of the rainbow trout cell line RTG-2. In a first set of experiments, the time course of Cd accumulation in RTG-2 cells exposed to a non-cytotoxic CdCl2 concentration (25 μM) was determined, as were the associated changes in the cellular sulfhydryl status. The cellular levels of total GSH, oxidized glutathione (GSSG), and cysteine were determined with fluorometric high-performance liquid chromatography (HPLC), and the intracellular Cd concentrations were determined with inductively coupled plasma mass spectrometry (ICP-MS). The Cd uptake during the first 24 h of exposure was linear before it approached a plateau at 48 h. The metal accumulation did not cause an alteration in cellular GSH, GSSG, or cysteine levels. In a second set of experiments, we examined whether the cellular sulfhydryl status modulates Cd accumulation. To this end, the following approaches were used: (a) untreated RTG-2 cells as controls, and (b) RTG-2 cells that were either depleted of GSH through pre-exposure to 1 mM L-buthionine-SR-sulfoximine (BSO), an inhibitor of glutathione synthesis, or the cellular sulfhydryl groups were blocked through treatment with 2.5 μM N-ethylmaleimide (NEM). Compared to the control cells, the cells depleted of intracellular GSH showed a 25% reduction in Cd accumulation. Likewise, the Cd accumulation was reduced by 25% in the RTG-2 cells with blocked sulfhydryl groups. However, the 25% decrease in cellular Cd accumulation in the sulfhydryl-manipulated cells was statistically not significantly different from the Cd accumulation in the control cells. The findings of this study suggest that the intracellular sulfhydryl and GSH status, in contrast to their importance for Cd toxicodynamics, is of limited importance for the toxicokinetics of Cd in fish cells.
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Aljerf L. A Gateway to Metal Resistance: Bacterial Response to Heavy Metal Toxicity in the Biological Environment. ACTA ACUST UNITED AC 2018. [DOI: 10.29328/journal.aac.1001012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Siscar R, Torreblanca A, del Ramo J, Solé M. Modulation of metallothionein and metal partitioning in liver and kidney of Solea senegalensis after long-term acclimation to two environmental temperatures. ENVIRONMENTAL RESEARCH 2014; 132:197-205. [PMID: 24813577 DOI: 10.1016/j.envres.2014.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 04/10/2014] [Accepted: 04/12/2014] [Indexed: 06/03/2023]
Abstract
Juveniles of Solea senegalensis were fed with commercial pellets under controlled conditions at two environmental Mediterranean temperatures (15 and 20°C) for two months. After this period, the accumulation of essential and non-essential metals and metallothionein (MT) levels was measured in liver and kidney by inductively coupled plasma mass spectrometry (ICP-MS) and pulse polarography, respectively. The bioaccumulation factor (BAF) for selected metals in both tissues was calculated in relation to levels present in the feed. Tissue partitioning (liver/kidney) and molar ratios, considering the metal protective mechanisms: MT and Selenium (Se), were included for evaluating the detoxification capacity of each tissue. Ag, Cd, Cu and Mn were preferentially accumulated in the liver whereas Co, Fe, Hg, Se and Zn were found in larger concentrations in the kidney, and higher temperature enhanced the accumulation of some of them, but not all. MT content in liver, but not in kidney, was also influenced by temperature changes and by length of exposure. The BAF revealed that Cu was taken up mainly by the liver whereas Se was efficiently taken up by both tissues. The high molar ratios of MT and most metals denoted the kidney's remarkable spare capacity for metal detoxification through MT binding. Moreover, the potential protective role of Se was also more evident in kidney as a higher Se:Cd and Se:Ag molar ratios were reached in this organ. In contrast to other fish, the storage of Cd in kidney was particularly low.
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Affiliation(s)
- R Siscar
- Departamento Biología Funcional y Antropología Física, Universitat de València, Dr. Moliner 50 Burjassot, 46100 València, Spain
| | - A Torreblanca
- Departamento Biología Funcional y Antropología Física, Universitat de València, Dr. Moliner 50 Burjassot, 46100 València, Spain
| | - J del Ramo
- Departamento Biología Funcional y Antropología Física, Universitat de València, Dr. Moliner 50 Burjassot, 46100 València, Spain
| | - M Solé
- Institut de Ciencies del Mar (ICM-CSIC), Passeig marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
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Chen L, Qu G, Sun X, Zhang S, Wang L, Sang N, Du Y, Liu J, Liu S. Characterization of the interaction between cadmium and chlorpyrifos with integrative techniques in incurring synergistic hepatoxicity. PLoS One 2013; 8:e59553. [PMID: 23516638 PMCID: PMC3597607 DOI: 10.1371/journal.pone.0059553] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 02/15/2013] [Indexed: 02/07/2023] Open
Abstract
Mixture toxicity is an important issue for the risk assessment of environmental pollutants, for which an extensive amount of data are necessary in evaluating their potential adverse health effects. However, it is very hard to decipher the interaction between compounds due to limited techniques. Contamination of heavy metals and organophosphoric insecticides under the environmental and biological settings poses substantial health risk to humans. Although previous studies demonstrated the co-occurrence of cadmium (Cd) and chlorpyrifos (CPF) in environmental medium and food chains, their interaction and potentially synergistic toxicity remain elusive thus far. Here we integrated the approaches of thin-layer chromatography and (1)H NMR to study the interaction between Cd(2+) and CPF in inducing hepatoxicity. A novel interaction was identified between Cd(2+) and CPF, which might be the bonding between Cd(2+) and nitrogen atom in the pyridine ring of CPF, or the chelation formation between one Cd(2+) and two CPF molecules. The Cd-CPF complex was conferred with distinct biological fate and toxicological performances from its parental components. We further demonstrated that the joint hepatoxicity of Cd ion and CPF was chiefly due to the Cd-CPF complex-facilitated intracellular transport associated with oxidative stress.
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Affiliation(s)
- Liqun Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
- College of Environment and Resource, Shanxi University, Taiyuan, Shanxi, China
| | - Guangbo Qu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Xue Sun
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Shuping Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Lei Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Nan Sang
- College of Environment and Resource, Shanxi University, Taiyuan, Shanxi, China
| | - Yuguo Du
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Jun Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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Water spinach (Ipomoea aquatic Forsk.) reduced the absorption of heavy metals in an in vitro bio-mimicking model system. Food Chem Toxicol 2012; 50:3862-6. [PMID: 22841954 DOI: 10.1016/j.fct.2012.07.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/05/2012] [Accepted: 07/13/2012] [Indexed: 11/22/2022]
Abstract
This study was conducted to investigate the effect of water spinach on bioaccessibility and intestinal uptake of heavy metals (Arsenic (As), Cadmium (Cd), and Lead (Pb)) using an in vitro digestion model with Caco-2 cells. Aliquots of each heavy metal were co-digested with each part of water spinach (stem and leaf) and then cultured with Caco-2 intestinal cells for 1h at 37 °C. Each heavy metal of As, Cd, and Pb was quantified using an ICP-OES. As the amount of stem and leaf (10, 50, 100, and 500 mg) of water spinach increased, bioaccessibility of As, Cd, and Pb decreased to 42.63%, 12.04%, and 26.17% by leaf and 30.37%, 43.27%, 40.07% by stem, respectively. Intestinal uptake of As, Cd, and Pb reduced to 65.8%, 25.7%, and 44.8% for leaf (500 mg) and 48.4%, 51.3%, and 64.3% for stem (500mg), respectively, compared with the control without leaf and stem. The leaf from water spinach was the most effective for decreasing both bioaccessibility and cellular uptake of Cd.
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ORTEGA RICHARD. APPLICATIONS OF NUCLEAR MICROPROBE ANALYSIS IN CANCER CELL BIOLOGY AND PHARMACOLOGY. ACTA ACUST UNITED AC 2011. [DOI: 10.1142/s0129083599000334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nuclear microprobe analysis studies in cancer cell pharmacology and biology carried out at Bordeaux-Gradignan are reported. The cellular pharmacology of two anticancer agents, cis-diammine-dichloroplatinum(II), and 4′-iodo-4′-deoxy-doxorubicin, were investigated, as well as the role of iron in neuroblastoma carcinogenesis, and chromium(III) in trans-generation carcinogenesis. Nuclear microprobe analysis, using PIXE and particle backscattering microanalysis, was able to reveal intracellular and tissue distributions of the elements under investigation. Moreover, the fully quantitative and multi-elemental character of nuclear microprobe analysis offered information on possible mechanisms of drug action, metal carcinogenesis, and interactions with endogenous trace elements in cancer cells.
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Affiliation(s)
- RICHARD ORTEGA
- LCNAB, CNRS UMR 5084, Université de Bordeaux 1, BP 120 Le Haut Vigneau, 33175 Gradignan, France
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Characterization of basolateral-to-apical transepithelial transport of cadmium in intestinal TC7 cell monolayers. Biometals 2011; 24:857-74. [PMID: 21424617 DOI: 10.1007/s10534-011-9440-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
Cadmium (Cd) is a toxic metal with an extremely long half-life in humans. The intestinal absorption of Cd has been extensively studied but the role the intestinal epithelium may play in metal excretion has never been considered. The basolateral (BL)-to-apical (AP) transepithelial transport of Cd was characterized in TC7 human intestinal cells. Both AP and BL uptakes varied with days in culture, and BL uptake was twofold higher compared to AP in differentiated cultures. A 50% increase in the BL uptake of 0.5 μM (109)Cd was observed at pH 8.5 in a chloride but not nitrate medium, suggesting the involvement of a pH-sensitive mechanism of transport for chloro-complexes. Fe and Zn inhibited the BL uptake of Cd whereas complexation by albumin had no effect, but the stimulatory effect of pH 8.5 was lost in the presence of albumin. The BL uptake of [(3)H]-MPP(+) and (109)Cd were both inhibited by decynium22 without reciprocal inhibition. MRP2 and MDR1 mRNA levels increased as a function of days in culture. A 25 and 20% decrease in the cellular AP efflux of Cd was observed in the presence of verapamil and probenecid, respectively. In cells treated with BSO, which lowered by 26% the total cellular thiol content, the inhibitory effect of verapamil increased, whereas that of probenecid decreased. These results reveal the existence of a decynium22-sensitive mechanism of transport for Cd at the BL membrane, and suggest the involvement of MDR1 and MRP2 in cellular Cd efflux at the AP membrane. It is conceivable that the intestinal epithelium may contribute to Cd blood excretion.
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Tandogan B, Ulusu NN. Effects of cadmium and zinc ions on purified lamb kidney cortex glucose-6-phosphate dehydrogenase activity. J Enzyme Inhib Med Chem 2008; 21:225-30. [PMID: 16789437 DOI: 10.1080/14756360500480533] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G-6-PD) is the first enzyme in the pentose phosphate pathway. Cadmium is a toxic heavy metal that inhibits several enzymes. Zinc is an essential metal but overdoses of zinc have toxic effects on enzyme activities. In this study G-6-PD from lamb kidney cortex was competitively inhibited by zinc both with respect to glucose-6-phosphate (G-6-P) and NADP+ with Ki values of 1.066 +/- 0.106 and 0.111 +/- 0.007 mM respectively whereas cadmium was a non-competitive inhibitor with respect to both G-6-P and NADP+ Ki values of 2.028 +/- 0.175 and 2.044 +/- 0.289 mM respectively.
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Affiliation(s)
- Berivan Tandogan
- Hacettepe University, Faculty of Medicine, Department of Biochemistry, 06100 Ankara, Turkey
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Wills NK, Ramanujam VMS, Chang J, Kalariya N, Lewis JR, Weng TX, van Kuijk FJGM. Cadmium accumulation in the human retina: effects of age, gender, and cellular toxicity. Exp Eye Res 2007; 86:41-51. [PMID: 17967453 DOI: 10.1016/j.exer.2007.09.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 08/17/2007] [Accepted: 09/14/2007] [Indexed: 11/30/2022]
Abstract
Tobacco smoking and aging are among the few factors linked to age-related macular degeneration (AMD), a major cause of blindness in the elderly. Recent studies indicate that cadmium (Cd), an environmental toxic trace metal, is approximately four-fold higher in the retinas of smokers compared to non-smokers. In this study, we determined the effects of age and gender on Cd accumulation in human retinal tissues, specifically the neural retina, retinal pigment epithelium (RPE), and choroid. Cadmium levels in cultured RPE cells or retinal tissues isolated from frozen donor eyes were measured using inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrophotometry (GF-AAS). Cadmium uptake in cultured human RPE cells (ARPE-19) was also assessed using GF-AAS. Toxic effects of cadmium were determined from cell loss (measured as a decrease in cell density) and lactate dehydrogenase release (an indicator of membrane disruption). In "young" eyes (< 55 years) Cd was highest in the retinal pigment epithelium and lowest in the neural retina. Cd was higher in all tissues in aged eyes (>or=55 years) and was significantly higher in the neural retina and RPE in older females. Cultured RPE cells exposed to Cd showed altered cell morphology, decreased cell survival, elevated ROS levels and concentration-dependent disruption of membrane integrity. We conclude that cadmium is accumulated differently in the neural retinal and RPE of older men and women. The deleterious effects of Cd on RPE cells indicate that this environmental toxin is a potentially important factor in age-related retinal disease.
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Affiliation(s)
- N K Wills
- Department of Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.
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Sures B, Scheef G, Klar B, Kloas W, Taraschewski H. Interaction between cadmium exposure and infection with the intestinal parasite Moniliformis moniliformis (Acanthocephala) on the stress hormone levels in rats. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2002; 119:333-340. [PMID: 12166667 DOI: 10.1016/s0269-7491(01)00340-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The impact of an infection with the acanthocephalan Moniliformis moniliformis and a simultaneous Cd-exposure on the stress hormone levels of rats was studied. Immediately after the application of cadmium to some rats, cortisol levels in all groups of rats, as quantified by radioimmunoassay (RIA), significantly increased. However, infections with M. moniliformis as well as the uptake of Cd reduced significantly the cortisol release compared to untreated controls. While catecholamine concentrations, as determined by high-performance liquid chromatography (HPLC), showed no clear tendency during the experimental period, the ratio of C(adrenaline)/C(noradrenaline) in the controls showed the significantly lowest value of all four groups after killing the animals. Thus, the acanthocephalan infection as well as the Cd-exposure and the combination of both treatments affect hormone homeostasis in the rats which probably lead to negative effects on the health of the rat. Therefore parasite infections must be carefully considered in environmental impact studies, as an important factor affecting the host's health.
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Affiliation(s)
- B Sures
- Zoologisches Institut I-Okologie/Parasitologie, Universität Karlsruhe, Germany.
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12
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Faurskov B, Bjerregaard HF. Chloride secretion in kidney distal epithelial cells (A6) evoked by cadmium. Toxicol Appl Pharmacol 2000; 163:267-78. [PMID: 10702366 DOI: 10.1006/taap.1999.8852] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of Cd(2+) on chloride secretion was examined in A6 renal epithelia cells by chloride-sensitive fluorescence (SPQ probe) and by the short-circuit-current (I(sc)) technique. Depleting the cells of Cl(-) suggests that the Cd(2+)-activated I(sc) (DeltaI(sc(Cd))) is dependent on the presence of Cl(-) ions. Among the Cl(-)-channel inhibitors the fenemates, flufenamic acid (FFA) and niflumic acid (NFA), and 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) significantly lowered DeltaI(sc(Cd)) compared with control level. In SPQ-loaded A6 cells, Cd(2+) evoked an increase in Cl(-) secretion ([DeltaCl(-)](Cd)), which significantly exceeded the basal Cl(-) transport and was blockable by FFA and NFA. The closely related metals, Zn(2+) or Ni(2+), were also able to activate Cl(-) secretion. Preexposure of Zn(2+) or Ni(2+) completely prevented [DeltaCl(-)](Cd), suggesting that Zn(2+) and Ni(2+) probably use similar mechanisms. Like Cd(2+), thapsigargin (TG), an inhibitor of intracellular Ca(2+)-ATPase and the Ca(2+)-ionophore A23187, induced an increase in I(sc). Moreover, TG and Cd(2+) were able to neutralize the responses of the counterparts as also observed in I(sc) measurements, which indicates that Cd(2+) activates Cl(-) secretion in a Ca(2+)-dependent manner. Hence, this study supports the idea that basolateral Cd(2+) (possibly also Zn(2+) and Ni(2+)), probably through a Ca(2+)-sensing receptor, causes calcium mobilization that activates apical fenemate-sensitive chloride channels leading to chloride secretion in A6 cells.
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Affiliation(s)
- B Faurskov
- Grenaa Central Hospital, Sygehusuej 6, 8500, Grenaa, Denmark.
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Foulkes EC. Transport of toxic heavy metals across cell membranes. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000; 223:234-40. [PMID: 10719835 DOI: 10.1046/j.1525-1373.2000.22334.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Membrane transport of nonessential toxic heavy metals (type D heavy metals) not only controls their access to intracellular target sites but also helps determine their uptake, distribution, and excretion from the body. The critical role of membranes in the toxicology of class D metals has attracted the attention of many investigators, and extensive information has been collected on the mechanism(s) of metal transfer across membranes. Characteristics of metal transport in different cells, or even on opposite sides of the same cell, or under different physiological conditions, are not identical, and no unitary hypothesis has been formulated to explain this process in all cells. However, it seems possible that the mechanisms proposed for different cells represent variations on a few common themes.
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Affiliation(s)
- E C Foulkes
- Department of Environmental Health, College of Medicine, University of Cincinnati, Ohio 45267-0056, USA.
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Abstract
The influx of the toxic cation Cd2+ was studied in fura 2-loaded rat cerebellar granule neurons. In cells depolarized with Ca2(+)-free, high-KCI solutions, the fluorescence emission ratio (R) increased in the presence of 100 microM Cd2(+). This increase was fully reversed by the Cd2+ chelator tetrakis(2-pyridylmethyl)ethylenediamine, indicating a cadmium influx into the cell. The rate of increase, dR/dt, was greatly reduced (67+/-5%) by 1 microM nimodipine and enhanced by 1 microM Bay K 8644. Concurrent application of nimodipine and omega-agatoxin IVA (200 nM) blocked Cd2+ permeation almost completely (88+/-5%), whereas omega-conotoxin MVIIC (2 microM) reduced dR/dt by 24+/-8%. These results indicate a primary role of voltage-dependent calcium channels in Cd2+ permeation. Stimulation with glutamate or NMDA and glycine also caused a rise of R in external Cd2+. Simultaneous application of nimodipine and omega-agatoxin IVA moderately reduced dR/dt (25+/-3%). NMDA-driven Cd2(+) entry was almost completely prevented by 1 mM Mg2+, 50 microM memantine, and 10 microM 5,7-dichlorokynurenic acid, suggesting a major contribution of NMDA-gated channels in glutamate-stimulated Cd2+ influx. Moreover, perfusion with alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate caused a slow increase of R. These results suggest that Cd2+ permeates the cell membrane mainly through the same pathways of Ca2+ influx.
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Affiliation(s)
- C Usai
- Istituto di Cibernetica e Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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Braeckman B, Smagghe G, Brutsaert N, Cornelis R, Raes H. Cadmium uptake and defense mechanism in insect cells. ENVIRONMENTAL RESEARCH 1999; 80:231-243. [PMID: 10092443 DOI: 10.1006/enrs.1998.3897] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The uptake of cadmium and the defense mechanism against this heavy metal were studied in the Aedes albopictus C6/36 cell line. The internalization of cadmium was a very quick process and exhibited saturation kinetics over the metal concentration gradient (1.37 to 131 micromol/L). Cd toxicity and influx were both shown to be temperature dependent. The uptake was not influenced by a 2, 4-dinitrophenol pretreatment but was significantly decreased by the Ca2+ antagonist verapamil. These data suggest that cadmium is readily taken up through mediated transport, not requiring metabolic energy. A considerable amount of the metal passes through the Ca2+ channels, but probably (an)other transporting molecule(s) also play(s) an important role in the uptake process. The remarkable, nonsigmoid viability pattern of Cd-treated cultures suggests that CdCl2 concentrations above 33 micromol/L induce a cellular defense system. This phenomenon went together with increased protein synthesis. We found a major induction of a group consisting of 71-, 75-, and 78-kDa proteins, probably belonging to the HSP70 family, as similar proteins were induced by heat shock. A slight induction of a 120-kDa protein also occurred. At the highest Cd concentrations 98-, 108-, and 110-kDa proteins were induced. These data suggest that heat shock proteins may play an important role in the Aedes cell protection against Cd insult.
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Affiliation(s)
- B Braeckman
- Physiology and Microbiology, University of Ghent, Ledeganckstraat 35, Ghent, B-9000, Belgium
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Novelli EL, Vieira EP, Rodrigues NL, Ribas BO. Risk assessment of cadmium toxicity on hepatic and renal tissues of rats. ENVIRONMENTAL RESEARCH 1998; 79:102-105. [PMID: 9841808 DOI: 10.1006/enrs.1998.3865] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Pollution and industrial practices result in concentrations of metals and other environmental agents that are related to environmental toxicity. A rat bioassay was utilized for the identification of toxic effects of cadmium intake. This demonstrated increased total urinary proteins and increased kidney weights in rats exposed to CdCl2 for 7 days, in drinking water (100 mg/L). Serum creatinine, total and direct bilirubin concentrations and alanine transaminase activity were increased in Cd-exposed rats, indicating renal and hepatic toxicity. It was also observed that lipoperoxide concentrations were increased, while Cu-Zn superoxide dismutase activity was decreased in rats treated with cadmium. This indicated that the renal and hepatic toxicity induced by cadmium involved superoxide radicals.
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Affiliation(s)
- E L Novelli
- Department of Chemistry, University Estadual Paulista, UNESP, Botucatu, São Paulo, 18618-000, Brazil
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Braeckman B, Cornelis R, Rzeznik U, Raes H. Uptake of HgCl2 and MeHgCl in an insect cell line (Aedes albopictus C6/36). ENVIRONMENTAL RESEARCH 1998; 79:33-40. [PMID: 9756678 DOI: 10.1006/enrs.1998.3841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We studied the uptake mechanism of mercuric chloride (Hg) and methylmercuric chloride (MeHg) in Aedes albopictus C6/36 cells. The uptake kinetics, together with the effect of temperature and a metabolic inhibitor (2, 4-dinitrophenol) on the mercury accumulation, were examined. Both amounts of internalized Hg and MeHg increased linearly with the extracellular concentration. Initially, the influx rate was high for both metal species but MeHg was found to accumulate seven times faster than Hg. At longer exposure times it leveled off for Hg, while for MeHg, the intracellular concentration decreased. Hg toxicity was not significantly influenced by elevated temperatures; in contrast there was a marked decrease of the LC50/24h value for MeHg. On the other hand, Hg accumulation was temperature dependent but MeHg was not. The different toxicity and uptake rate of both mercury compounds can be explained in terms of membrane permeability and target site. For Hg the main target seems to be the plasma membrane, while MeHg readily crosses this barrier and reacts with intracellular targets. 2, 4-Dinitrophenol had no effect on the accumulation of Hg but that of MeHg was doubled. This increased MeHg accumulation might be the result of the inhibition of an active MeHg efflux mechanism; this is in agreement with the MeHg influx kinetics. Despite these differences between Hg and MeHg, which probably result from their physicochemical properties, our experiments indicate that, for both mercury species, simple diffusion is probably the main way to entrance in Aedes cells.
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Affiliation(s)
- B Braeckman
- Department of Biochemistry, Physiology, and Microbiology, University of Ghent, Belgium.
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Rayms-Keller A, Olson KE, McGaw M, Oray C, Carlson JO, Beaty BJ. Effect of heavy metals on Aedes aegypti (Diptera: Culicidae) larvae. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 1998; 39:41-47. [PMID: 9515074 DOI: 10.1006/eesa.1997.1605] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Studies were conducted to determine the biological effects of heavy metals on the development of Aedes aegypti. Embryos immersed in 32 ppm Cu or 5 ppm Cd did not hatch. The arrest of hatching was in part reversible by removal of the heavy metals. The mortality rate of third-instar larvae exposed to heavy metals for 24 h was metal and dose dependent; the 50% lethal concentration (LC50) endpoints were 3.1, 16.5, and 33 ppm for Hg, Cd, and Cu, respectively. Interestingly, a proportion of Aedes aegypti third-instar larvae exposed to either Cu or Cd for 24 h failed to produce a dissectable peritrophic matrix. This failure to produce a dissectable peritrophic matrix also was metal and dose dependent. These results are discussed in the context of Aedes aegypti as a model system for investigating the molecular biological effects of heavy metals in aquatic insects.
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Affiliation(s)
- A Rayms-Keller
- Department of Microbiology, Colorado State University, Fort Collins 80523, USA
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Souza V, Bucio L, Jay D, Chávez E, Gutiérrez-Ruiz MC. Effect of cadmium on calcium transport in a human fetal hepatic cell line (WRL-68 cells). Toxicology 1996; 112:97-104. [PMID: 8814339 DOI: 10.1016/0300-483x(96)03335-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Toxic metals appear to use the transport pathways that exist for biologically essential metals. Calcium uptake in cells occurs through specific membrane channels. Since cadmium inhibits calcium uptake, this study was carried on to elucidate the mechanism of Cd interference with calcium transport using the fetal hepatic cell line WRL-68 as an in vitro model. Ca accumulation by WRL-68 cells presented an initial rapid phase, followed by a sustained phase of slower accumulation over a 60 min period. A concentration of 50 microM CdCl2 produced 39% inhibition of the uptake of CaCl2 (100 microM), while 100 microM nifedipine or verapamil decreased Ca accumulation by 35 and 63%, respectively. All Cd concentrations tested produced significant decrease in Ca uptake in a concentration-dependent manner at 1 min and thereafter, although with 10 microM CdCl2 no significant difference was found after 30 min of incubation. From the Lineweaver-Burk plot, we found that Cd exerted a competitive inhibition on Ca uptake, since there was no significant effect on the Vmax but an increased K(m). A second order rate constant of Cd inactivation of 0.061 mM-1.s-1 was determined from the course of Ca uptake during Cd inhibition. SH groups seemed to play an essential role in Ca inhibition uptake by Cd because the inhibition of Ca accumulation by 50 microM Cd was practically reversed after the addition of dithiothreitol.
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Affiliation(s)
- V Souza
- Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. México
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Xu C, Johnson JE, Singh PK, Jones MM, Yan H, Carter CE. In vivo studies of cadmium-induced apoptosis in testicular tissue of the rat and its modulation by a chelating agent. Toxicology 1996; 107:1-8. [PMID: 8597027 DOI: 10.1016/0300-483x(95)03195-l] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In vivo CdCl2-induced apoptotic DNA fragmentation in the testes of the male Wistar rat has been demonstrated on agarose gel. Characteristic DNA migration patterns (laddering) provide evidence of apoptosis (programmed cell death) in testicular tissue of rats administered CdCl2 at a level of 0.03 mmol/kg 48 h previously. Evidence that administration of an appropriate cadmium chelating agent within the first 24 h can suppress some or all of the apoptotic changes in testicular DNA has also been obtained for the first time. A greater reduction in apoptosis is observed as the interval between the administration of the cadmium and that of the chelating agent is shortened. Administration of monoisoamyl meso-2,3-dimercaptosuccinate (Mi-ADMS) to male Wistar rats given CdCl2 is effective in the modulation of the typically apoptotic DNA fragmentation and associated histopathologic injury when the antagonist is given within approximately 1 h after the CdCl2 exposure. When the antagonist is given at later times there is a progressively more pronounced degradation of the DNA into oligonucleotides as seen in the typical electrophoretic DNA ladder pattern found with apoptosis. There is also a progressive increase in histopathological tissue changes as the antagonist is administered at progressively greater intervals after the cadmium.
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Affiliation(s)
- C Xu
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
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Abstract
Metals have been mined and used since ancient times. The industrial era has seen a sharp increase in both the amounts and variety of metals that find applications in industry. The inadvertent release of metals, such as from fossil fuel consumption, also adds to the global burden. A number of catastrophic outbreaks have alerted us to the occupational and environmental health risks. Life on this planet has evolved in the presence of metals. Cells learned to make use of the more abundant metals in the Archean oceans as an integral component in their structure and function. Today, we inherit these as the essential metals. At the same time, evolving life must have developed means of coping with the potentially toxic actions of metals. The appearance of oxygen in the atmosphere in the Precambrian period also resulted in cells both using and developing protective mechanisms against what must have been a highly toxic, reactive gas. Atmospheric oxygen must have increased the solubility of many metals as insoluble metal sulfides were oxidized to the more soluble sulfates. It may be no coincidence that the protective mechanisms for oxygen are also used to protect against a number of toxic metals. Selected examples are given on the role of evolution in metal toxicology, specifically, examples where the normal function of essential metals is deranged by competition with nonessential metals. Examples are also given of protective mechanisms that involve enzymes or cofactors involved in the oxygen defense system.
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Affiliation(s)
- T Clarkson
- Department of Environmental Medicine, University of Rochester School of Medicine, New York 14642, USA
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