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Settivari R, LeVora J, Nass R. The divalent metal transporter homologues SMF-1/2 mediate dopamine neuron sensitivity in caenorhabditis elegans models of manganism and parkinson disease. J Biol Chem 2009; 284:35758-68. [PMID: 19801673 PMCID: PMC2791006 DOI: 10.1074/jbc.m109.051409] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 09/17/2009] [Indexed: 01/26/2023] Open
Abstract
Parkinson disease (PD) and manganism are characterized by motor deficits and a loss of dopamine (DA) neurons in the substantia nigra pars compacta. Epidemiological studies indicate significant correlations between manganese exposure and the propensity to develop PD. The vertebrate divalent metal transporter-1 (DMT-1) contributes to maintaining cellular Mn(2+) homeostasis and has recently been implicated in Fe(2+)-mediated neurodegeneration in PD. In this study we describe a novel model for manganism that incorporates the genetically tractable nematode Caenorhabditis elegans. We show that a brief exposure to Mn(2+) increases reactive oxygen species and glutathione production, decreases oxygen consumption and head mitochondria membrane potential, and confers DA neuronal death. DA neurodegeneration is partially dependent on a putative homologue to DMT-1, SMF-1, as genetic knockdown or deletion partially inhibits the neuronal death. Mn(2+) also amplifies the DA neurotoxicity of the PD-associated protein alpha-synuclein. Furthermore, both SMF-1 and SMF-2 are expressed in DA neurons and contribute to PD-associated neurotoxicant-induced DA neuron death. These studies describe a C. elegans model for manganism and show that DMT-1 homologues contribute to Mn(2+)- and PD-associated DA neuron vulnerability.
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Affiliation(s)
- Raja Settivari
- From the
Department of Pharmacology and Toxicology
- Center for Environmental Health, and
| | - Jennifer LeVora
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Richard Nass
- From the
Department of Pharmacology and Toxicology
- Center for Environmental Health, and
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202
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52
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Benedetto A, Au C, Aschner M. Manganese-Induced Dopaminergic Neurodegeneration: Insights into Mechanisms and Genetics Shared with Parkinson’s Disease. Chem Rev 2009; 109:4862-84. [DOI: 10.1021/cr800536y] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Alexandre Benedetto
- Department of Pediatrics, Center for Molecular Neuroscience, Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0414
| | - Catherine Au
- Department of Pediatrics, Center for Molecular Neuroscience, Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0414
| | - Michael Aschner
- Department of Pediatrics, Center for Molecular Neuroscience, Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0414
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53
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Parkel S, Näsman J, Rinken A. Enhancement of agonist binding to 5-HT1A receptors in rat brain membranes by millimolar Mn2+. Neurosci Lett 2009; 457:32-5. [DOI: 10.1016/j.neulet.2009.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 04/01/2009] [Accepted: 04/02/2009] [Indexed: 11/28/2022]
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54
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Stanwood GD, Leitch DB, Savchenko V, Wu J, Fitsanakis VA, Anderson DJ, Stankowski JN, Aschner M, McLaughlin B. Manganese exposure is cytotoxic and alters dopaminergic and GABAergic neurons within the basal ganglia. J Neurochem 2009; 110:378-89. [PMID: 19457100 DOI: 10.1111/j.1471-4159.2009.06145.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Manganese is an essential nutrient, integral to proper metabolism of amino acids, proteins and lipids. Excessive environmental exposure to manganese can produce extrapyramidal symptoms similar to those observed in Parkinson's disease (PD). We used in vivo and in vitro models to examine cellular and circuitry alterations induced by manganese exposure. Primary mesencephalic cultures were treated with 10-800 microM manganese chloride which resulted in dramatic changes in the neuronal cytoskeleton even at subtoxic concentrations. Using cultures from mice with red fluorescent protein driven by the tyrosine hydroxylase (TH) promoter, we found that dopaminergic neurons were more susceptible to manganese toxicity. To understand the vulnerability of dopaminergic cells to chronic manganese exposure, mice were given i.p. injections of MnCl(2) for 30 days. We observed a 20% reduction in TH-positive neurons in the substantia nigra pars compacta (SNpc) following manganese treatment. Quantification of Nissl bodies revealed a widespread reduction in SNpc cell numbers. Other areas of the basal ganglia were also altered by manganese as evidenced by the loss of glutamic acid decarboxylase 67 in the striatum. These studies suggest that acute manganese exposure induces cytoskeletal dysfunction prior to degeneration and that chronic manganese exposure results in neurochemical dysfunction with overlapping features to PD.
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Affiliation(s)
- Gregg D Stanwood
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37620, USA
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55
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Papaefthimiou C, Antonopoulou E, Theophilidis G. Inhibitory vs. protective effects of N-acetyl-l-cysteine (NAC) on the electromechanical properties of the spontaneously beating atria of the frog (Rana ridibunda): An ex vivo study. Toxicol In Vitro 2009; 23:272-80. [DOI: 10.1016/j.tiv.2008.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Revised: 11/04/2008] [Accepted: 12/05/2008] [Indexed: 10/21/2022]
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56
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Martínez-Villaluenga C, Zieliński H, Frias J, Piskuła MK, Kozłowska H, Vidal-Valverde C. Antioxidant capacity and polyphenolic content of high-protein lupin products. Food Chem 2009. [DOI: 10.1016/j.foodchem.2008.05.040] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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57
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Lazrishvili IL, Shukakidze AA, Chkhartishvili NN, Bikashvili TZ. Morphological changes and manganese content in the brains of rat pups subjected to subchronic poisoning with manganese chloride. ACTA ACUST UNITED AC 2008; 39:7-12. [PMID: 19089633 DOI: 10.1007/s11055-008-9092-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 07/11/2007] [Indexed: 11/25/2022]
Abstract
Morphological changes in neurons and the distributions of nerve and glial cells were studied, the glial index was calculated, and manganese (Mn) contents were determined in the caudate nucleus, the nucleus accumbens, the dorsal and ventral septal nuclei, and the frontoparietal areas of the cerebral cortex in the 40-day-old offspring of rats given different doses (10 and 20 mg/kg) of manganese chloride (MnCl2.4H2O) 15-20 days before pregnancy, during pregnancy, and for one month after parturition with the first portion of food. Mn poisoning increased Mn contents in the brains of rat pups, damaged a small proportion of neurons, and produced marked gliosis. These changes are believed to underlie previously described impairments to learning processes and emotional state in rat pups.
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Affiliation(s)
- I L Lazrishvili
- Laboratory for Functional Neuroanatomy, I. S. Beritashvili Institute of Physiology, Tbilisi, Georgia.
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58
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Jones DC, Miller GW. The effects of environmental neurotoxicants on the dopaminergic system: A possible role in drug addiction. Biochem Pharmacol 2008; 76:569-81. [DOI: 10.1016/j.bcp.2008.05.010] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 05/01/2008] [Accepted: 05/05/2008] [Indexed: 11/29/2022]
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59
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Martin K, Huggins T, King C, Carroll MA, Catapane EJ. The neurotoxic effects of manganese on the dopaminergic innervation of the gill of the bivalve mollusc, Crassostrea virginica. Comp Biochem Physiol C Toxicol Pharmacol 2008; 148:152-9. [PMID: 18547869 PMCID: PMC2533860 DOI: 10.1016/j.cbpc.2008.05.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Revised: 04/28/2008] [Accepted: 05/02/2008] [Indexed: 10/22/2022]
Abstract
We examined effects of manganese on the nervous system and innervation of lateral cilia of Crassostrea virginica. While essential in trace amounts, tissue manganese accumulation is neurotoxic, inducing Manganism, a Parkinson's-like disease in humans. Lateral cilia of the gill of C. virginica are controlled by a reciprocal serotonergic-dopaminergic innervation from their ganglia. Oysters were incubated 3 days in the presence of up to 1 mM manganese, followed by superfusion of the cerebral ganglia, visceral ganglia or gill with dopamine or serotonin. Beating rates of cilia were measured by stroboscopic microscopy of isolated gill preparations or gill preparations with the ipsilateral cerebral and/or visceral ganglia attached. Acute manganese treatments impaired the dopaminergic, cilio-inhibitory system, while having no effect on the serotonergic, cilio-excitatory system, which is in agreement with the proposed mechanism of manganese toxicity in humans. Manganese treatments also decreased endogenous dopamine levels in the cerebral and visceral ganglia, and gills, but not serotonin levels. We demonstrated that manganese disrupts the animal's dopaminergic system, and also that this preparation can be used to investigate mechanisms that underlie manganese neurotoxicity. It also may serve as a model in pharmacological studies of drugs to treat or prevent Manganism and other dopaminergic cell disorders.
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Affiliation(s)
| | | | | | | | - Edward J. Catapane
- Corresponding author: Department of Biology, Medgar Evers College, 1150 Carroll Street, Brooklyn, NY 11225, USA, Tel: 718.270.6203, fax 718.270.6196, email
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60
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Peterson RT, Nass R, Boyd WA, Freedman JH, Dong K, Narahashi T. Use of non-mammalian alternative models for neurotoxicological study. Neurotoxicology 2008; 29:546-55. [PMID: 18538410 DOI: 10.1016/j.neuro.2008.04.006] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/28/2008] [Accepted: 04/01/2008] [Indexed: 11/26/2022]
Abstract
The field of neurotoxicology needs to satisfy two opposing demands: the testing of a growing list of chemicals, and resource limitations and ethical concerns associated with testing using traditional mammalian species. National and international government agencies have defined a need to reduce, refine or replace mammalian species in toxicological testing with alternative testing methods and non-mammalian models. Toxicological assays using alternative animal models may relieve some of this pressure by allowing testing of more compounds while reducing expense and using fewer mammals. Recent advances in genetic technologies and the strong conservation between human and non-mammalian genomes allow for the dissection of the molecular pathways involved in neurotoxicological responses and neurological diseases using genetically tractable organisms. In this review, applications of four non-mammalian species, zebrafish, cockroach, Drosophila, and Caenorhabditis elegans, in the investigation of neurotoxicology and neurological diseases are presented.
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61
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Moschou M, Kosmidis EK, Kaloyianni M, Geronikaki A, Dabarakis N, Theophilidis G. In vitro assessment of the neurotoxic and neuroprotective effects of N-acetyl-l-cysteine (NAC) on the rat sciatic nerve fibers. Toxicol In Vitro 2008; 22:267-74. [PMID: 17959349 DOI: 10.1016/j.tiv.2007.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 09/07/2007] [Accepted: 09/07/2007] [Indexed: 11/28/2022]
Affiliation(s)
- Magdalini Moschou
- Laboratory of Animal Physiology, Department of Zoology, School of Biology, Aristotle University, Thessaloniki 54124, Hellas, Greece
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62
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Zhang P, Hatter A, Liu B. Manganese chloride stimulates rat microglia to release hydrogen peroxide. Toxicol Lett 2007; 173:88-100. [PMID: 17669604 PMCID: PMC2100035 DOI: 10.1016/j.toxlet.2007.06.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 06/21/2007] [Accepted: 06/21/2007] [Indexed: 12/21/2022]
Abstract
Elevated exposure to manganese is known to cause neurodegeneration in the basal ganglia and to induce movement abnormalities called manganism. However, the underlying mechanism of action is not fully understood. Activation of the resident immune cells in the brain, microglia that release a variety of neurotoxic factors, has been implicated to contribute to neurodegeneration. Of the various neurotoxic factors released by activated microglia, reactive oxygen species such as superoxide and hydrogen peroxide are particularly detrimental to the survival of the oxidative damage-prone neurons. In this study, we report that exposure of rat microglia to manganese chloride (MnCl(2)) resulted in a time- and concentration-dependent release of hydrogen peroxide (H(2)O(2)). The MnCl(2)-stimulated microglial H(2)O(2) release was sensitive to inhibitors of mitogen-activated protein kinases (MAPK) but not that of NADPH oxidase. MnCl(2)-induced a rapid activation of the extracellular signal-regulated kinase (ERK) and p38-MAPK in microglia that appeared to precede the MnCl(2)-induced H(2)O(2) release, suggesting that ERK and p38-MAPK influenced the MnCl(2)-induced H(2)O(2) release in microglia. In summary, these results demonstrate that manganese chloride is capable of activating microglia to release ROS and MAPK may, in part, be key regulators of the process. These findings may shed significant light on the potential role of microglia in the manganese-induced neurotoxicity.
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Affiliation(s)
- Ping Zhang
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Angela Hatter
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Bin Liu
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
- Corresponding author: Tel.: +1 352 392 3972; Fax: +1 352 392 9187. E-mail address:
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63
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Aschner M, Guilarte TR, Schneider JS, Zheng W. Manganese: recent advances in understanding its transport and neurotoxicity. Toxicol Appl Pharmacol 2007; 221:131-47. [PMID: 17466353 PMCID: PMC1950780 DOI: 10.1016/j.taap.2007.03.001] [Citation(s) in RCA: 415] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 01/16/2007] [Accepted: 03/02/2007] [Indexed: 11/19/2022]
Abstract
The present review is based on presentations from the meeting of the Society of Toxicology in San Diego, CA (March 2006). It addresses recent developments in the understanding of the transport of manganese (Mn) into the central nervous system (CNS), as well as brain imaging and neurocognitive studies in non-human primates aimed at improving our understanding of the mechanisms of Mn neurotoxicity. Finally, we discuss potential therapeutic modalities for treating Mn intoxication in humans.
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Affiliation(s)
- Michael Aschner
- Department of Pediatrics, and The Kennedy Center for Research on Human Development, Vanderbilt University, School of Medicine, Nashville, TN 37232-2495, USA.
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64
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Choi CJ, Anantharam V, Saetveit NJ, Houk RS, Kanthasamy A, Kanthasamy AG. Normal cellular prion protein protects against manganese-induced oxidative stress and apoptotic cell death. Toxicol Sci 2007; 98:495-509. [PMID: 17483122 PMCID: PMC3407037 DOI: 10.1093/toxsci/kfm099] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The normal prion protein is abundantly expressed in the central nervous system, but its biological function remains unclear. The prion protein has octapeptide repeat regions that bind to several divalent metals, suggesting that the prion proteins may alter the toxic effect of environmental neurotoxic metals. In the present study, we systematically examined whether prion protein modifies the neurotoxicity of manganese (Mn) by comparing the effect of Mn on mouse neural cells expressing prion protein (PrP(C)-cells) and prion-knockout (PrP(KO)-cells). Exposure to Mn (10microM-10mM) for 24 h produced a dose-dependent cytotoxic response in both PrP(C)-cells and PrP(KO)-cells. Interestingly, PrP(C)-cells (EC(50) 117.6microM) were more resistant to Mn-induced cytotoxicity, as compared to PrP(KO)-cells (EC(50) 59.9microM), suggesting a protective role for PrP(C) against Mn neurotoxicity. Analysis of intracellular Mn levels showed less Mn accumulation in PrP(C)-cells as compared to PrP(KO)-cells, but no significant changes in the expression of the metal transporter proteins transferrin and DMT-1. Furthermore, Mn-induced mitochondrial depolarization and reactive oxygen species (ROS) generation were significantly attenuated in PrP(C)-cells as compared to PrP(KO)-cells. Measurement of antioxidant status revealed similar basal levels of glutathione (GSH) in PrP(C)-cells and PrP(KO)-cells; however, Mn treatment caused greater depletion of GSH in PrP(KO)-cells. Mn-induced mitochondrial depolarization and ROS production were followed by time- and dose-dependent activation of the apoptotic cell death cascade involving caspase-9 and -3. Notably, DNA fragmentation induced by both Mn treatment and the oxidative stress inducer hydrogen peroxide (100microM) was significantly suppressed in PrP(C)-cells as compared to PrP(KO)-cells. Together, these results demonstrate that prion protein interferes with divalent metal Mn uptake and protects against Mn-induced oxidative stress and apoptotic cell death.
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Affiliation(s)
- Christopher J Choi
- Neuroscience and Toxicology Graduate Programs, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa 50011, USA
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65
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Sistrunk SC, Ross MK, Filipov NM. Direct effects of manganese compounds on dopamine and its metabolite Dopac: an in vitro study. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2007; 23:286-296. [PMID: 18449324 PMCID: PMC1868515 DOI: 10.1016/j.etap.2006.11.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Following combustion of fuel containing the additive methylcyclopentadienyl-manganese-tricarbonyl (MMT), manganese phosphate (MnPO(4)) and manganese sulfate (MnSO(4)) are emitted in the atmosphere. Manganese chloride (MnCl(2)), another Mn(2+) species, is widely used experimentally. Using rat striatal slices, we found that MnPO(4) decreased tissue and media dopamine (DA) and media Dopac (a DA metabolite) levels substantially more than either MnCl(2) or MnSO(4); antioxidants were partially protective. Also, both MnCl(2) and MnPO(4) (more potently) oxidized DA and Dopac even in the absence of tissue in the media, suggesting a direct interaction between Mn and DA/Dopac. Because aminochrome is a major oxidation product of DA, we next determined whether MnPO(4) will be more potent in forming aminochrome than MnCl(2) or MnSO(4) which, indeed, was the case. Thus, a potential additional mechanism for the neurotoxic effects of environmentally-relevant forms of Mn, MnPO(4) in particular, is the generation of reactive DA intermediates.
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Affiliation(s)
- Shannon C Sistrunk
- Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
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66
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Improvement in food intake and nutritive utilization of protein from Lupinus albus var. multolupa protein isolates supplemented with ascorbic acid. Food Chem 2007. [DOI: 10.1016/j.foodchem.2006.09.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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67
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Taylor MD, Erikson KM, Dobson AW, Fitsanakis VA, Dorman DC, Aschner M. Effects of inhaled manganese on biomarkers of oxidative stress in the rat brain. Neurotoxicology 2006; 27:788-97. [PMID: 16842851 DOI: 10.1016/j.neuro.2006.05.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 05/09/2006] [Accepted: 05/12/2006] [Indexed: 12/11/2022]
Abstract
Manganese (Mn) is a ubiquitous and essential element that can be toxic at high doses. In individuals exposed to high levels of this metal, Mn can accumulate in various brain regions, leading to neurotoxicity. In particular, Mn accumulation in the mid-brain structures, such as the globus pallidus and striatum, can lead to a Parkinson's-like movement disorder known as manganism. While the mechanism of this toxicity is currently unknown, it has been postulated that Mn may be involved in the generation of reactive oxygen species (ROS) through interaction with intracellular molecules, such as superoxide and hydrogen peroxide, produced within mitochondria. Conversely, Mn is a required component of an important antioxidant enzyme, Mn superoxide dismutase (MnSOD), while glutamine synthetase (GS), a Mn-containing astrocyte-specific enzyme, is exquisitely sensitive to oxidative stress. To investigate the possible role of oxidative stress in Mn-induced neurotoxicity, a series of inhalation studies was performed in neonatal and adult male and female rats as well as senescent male rats exposed to various levels of airborne-Mn for periods of time ranging from 14 to 90 days. Oxidative stress was then indirectly assessed by measuring glutathione (GSH), metallothionein (MT), and GS levels in several brain regions. MT and GS mRNA levels and regional brain Mn concentrations were also determined. The collective results of these studies argue against extensive involvement of ROS in Mn neurotoxicity in rats of differing genders and ages. There are, however, instances of changes in individual endpoints consistent with oxidative stress in certain brain tissues.
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Affiliation(s)
- Michael D Taylor
- Environmental Science, Afton Chemical Corporation, 500 Spring Street, Richmond, VA 23219, USA.
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68
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Latchoumycandane C, Anantharam V, Kitazawa M, Yang Y, Kanthasamy A, Kanthasamy AG. Protein Kinase Cδ Is a Key Downstream Mediator of Manganese-Induced Apoptosis in Dopaminergic Neuronal Cells. J Pharmacol Exp Ther 2004; 313:46-55. [PMID: 15608081 DOI: 10.1124/jpet.104.078469] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Manganese (Mn) exposure causes manganism, a neurological disorder similar to Parkinson's disease. However, the cellular mechanism by which Mn induces dopaminergic neuronal cell death remains unclear. In the present study, we sought to investigate the key downstream apoptotic cell signaling events that contribute to Mn-induced cell death in mesencephalic dopaminergic neuronal (N27) cells. Mn exposure induced a dose-dependent increase in neuronal cell death in N27 cells. The cell death was accompanied by sequential activation of mitochondrial-dependent proapoptotic events, including cytochrome c release, caspase-3 activation, and DNA fragmentation, but not caspase-8 activation, indicating that the mitochondrial-dependent apoptotic cascade primarily triggers Mn-induced apoptosis. Notably, Mn treatment proteolytically activated protein kinase Cdelta (PKCdelta), a member of a novel class of protein kinase C. The caspase-3 specific inhibitor benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone (Z-DEVD-FMK) significantly blocked PKCdelta cleavage and its kinase activity, indicating that caspase-3 mediates the proteolytic activation. Cotreatment with the PKCdelta inhibitor rottlerin or the caspase-3 inhibitor Z-DEVD-FMK almost completely blocked Mn-induced DNA fragmentation. Additionally, N27 cells expressing a catalytically inactive PKCdelta(K376R) protein (PKCdelta dominant negative mutant) or a caspase cleavage resistant PKCdelta(D327A) protein (PKCdelta cleavage resistant mutant) were found to be resistant to Mn-induced apoptosis. To further establish the proapoptotic role of PKCdelta, RNA interference-mediated gene knockdown was performed. Small interfering RNA suppression of PKCdelta expression protected N27 cells from Mn-induced apoptotic cell death. Collectively, these results suggest that caspase-3-dependent proteolytic activation of PKCdelta plays a key role in Mn-induced apoptotic cell death.
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Affiliation(s)
- Calivarathan Latchoumycandane
- Parkinson's Disorder Research Laboratory, Department of Biomedical Sciences, 2008 Veterinary Medicine Bldg., Iowa State University, Ames, IA 50011-1250, USA
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