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Tanihira H, Fujiwara T, Kikuta S, Homma N, Osanai M. Manganese Dynamics in Mouse Brain After Systemic MnCl 2 Administration for Activation-Induced Manganese-Enhanced MRI. Front Neural Circuits 2022; 15:787692. [PMID: 34987361 PMCID: PMC8722453 DOI: 10.3389/fncir.2021.787692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/16/2021] [Indexed: 12/02/2022] Open
Abstract
Activation-induced manganese-enhanced MRI (AIM-MRI) is an attractive tool for non-invasively mapping whole brain activities. Manganese ions (Mn2+) enter and accumulate in active neurons via calcium channels. Mn2+ shortens the longitudinal relaxation time (T1) of H+, and the longitudinal relaxation rate R1 (1/T1) is proportional to Mn2+ concentration. Thus, AIM-MRI can map neural activities throughout the brain by assessing the R1 map. However, AIM-MRI is still not widely used, partially due to insufficient information regarding Mn2+ dynamics in the brain. To resolve this issue, we conducted a longitudinal study looking at manganese dynamics after systemic administration of MnCl2 by AIM-MRI with quantitative analysis. In the ventricle, Mn2+ increased rapidly within 1 h, remained high for 3 h, and returned to near control levels by 24 h after administration. Microdialysis showed that extracellular Mn returned to control levels by 4 h after administration, indicating a high concentration of extracellular Mn2+ lasts at least about 3 h after administration. In the brain parenchyma, Mn2+ increased slowly, peaked 24–48 h after administration, and returned to control level by 5 days after a single administration and by 2 weeks after a double administration with a 24-h interval. These time courses suggest that AIM-MRI records neural activity 1–3 h after MnCl2 administration, an appropriate timing of the MRI scan is in the range of 24–48 h following systemic administration, and at least an interval of 5 days or a couple of weeks for single or double administrations, respectively, is needed for a repeat AIM-MRI experiment.
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Affiliation(s)
- Hiroki Tanihira
- Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tomonori Fujiwara
- Faculty of Health and Medical Care, Saitama Medical University, Hidaka, Japan.,Department of Medical Physiology, Faculty of Medicine, Kyorin University, Mitaka, Japan
| | - Satomi Kikuta
- Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan.,Department of Neurophysiology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Noriyasu Homma
- Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan.,Department of Intelligent Biomedical Systems Engineering, Graduate Scholl of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Makoto Osanai
- Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan.,Laboratory for Physiological Functional Imaging, Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
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Hiney JK, Srivastava VK, Dees WL. Manganese induces IGF-1 and cyclooxygenase-2 gene expressions in the basal hypothalamus during prepubertal female development. Toxicol Sci 2011; 121:389-96. [PMID: 21402727 DOI: 10.1093/toxsci/kfr057] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Precocious puberty is a significant child health problem, especially in girls, because 95% of cases are idiopathic. Our earlier studies demonstrated that low-dose levels of manganese (Mn) caused precocious puberty via stimulating the secretion of luteinizing hormone-releasing hormone (LHRH). Because glial-neuronal communications are important for the activation of LHRH secretion at puberty, we investigated the effects of prepubertal Mn exposure on specific glial-derived puberty-related genes known to affect neuronal LHRH release. Animals were supplemented with MnCl(2) (10 mg/kg) or saline by gastric gavage from day 12 until day 22 or day 29, then decapitated, and brains removed. The site of LHRH release is the medial basal hypothalamus (MBH), and tissues from this area were analyzed by real-time PCR for transforming growth factor α (TGFα), insulin-like growth factor-1 (IGF-1), and cyclooxygenase-2 (COX-2) messenger RNA levels. Protein levels for IGF-1 receptor (IGF-1R) were measured by Western blot analysis. LHRH gene expression was measured in the preoptic area/anteroventral periventricular (POA/AVPV) region. In the MBH, at 22 days, IGF-1 gene expression was increased (p < 0.05) with a concomitant increase (p < 0.05) in IGF-1R protein expression. Mn also increased (p < 0.01) COX-2 gene expression. At 29 days, the upregulation of IGF-1 (p < 0.05) and COX-2 (p < 0.05) continued in the MBH. At this time, we observed increased (p < 0.05) LHRH gene expression in the POA/AVPV. Additionally, Mn stimulated prostaglandin E(2) and LHRH release from 29-day-old median eminences incubated in vitro. These results demonstrate that Mn, through the upregulation of IGF-1 and COX-2, may promote maturational events and glial-neuronal communications facilitating the increased neurosecretory activity, including that of LHRH, resulting in precocious pubertal development.
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Affiliation(s)
- Jill K Hiney
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843-4458, USA
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Extracellular dopamine potentiates mn-induced oxidative stress, lifespan reduction, and dopaminergic neurodegeneration in a BLI-3-dependent manner in Caenorhabditis elegans. PLoS Genet 2010; 6. [PMID: 20865164 PMCID: PMC2928785 DOI: 10.1371/journal.pgen.1001084] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 07/22/2010] [Indexed: 01/30/2023] Open
Abstract
Parkinson's disease (PD)-mimicking drugs and pesticides, and more recently PD-associated gene mutations, have been studied in cell cultures and mammalian models to decipher the molecular basis of PD. Thus far, a dozen of genes have been identified that are responsible for inherited PD. However they only account for about 8% of PD cases, most of the cases likely involving environmental contributions. Environmental manganese (Mn) exposure represents an established risk factor for PD occurrence, and both PD and Mn-intoxicated patients display a characteristic extrapyramidal syndrome primarily involving dopaminergic (DAergic) neurodegeneration with shared common molecular mechanisms. To better understand the specificity of DAergic neurodegeneration, we studied Mn toxicity in vivo in Caenorhabditis elegans. Combining genetics and biochemical assays, we established that extracellular, and not intracellular, dopamine (DA) is responsible for Mn-induced DAergic neurodegeneration and that this process (1) requires functional DA-reuptake transporter (DAT-1) and (2) is associated with oxidative stress and lifespan reduction. Overexpression of the anti-oxidant transcription factor, SKN-1, affords protection against Mn toxicity, while the DA-dependency of Mn toxicity requires the NADPH dual-oxidase BLI-3. These results suggest that in vivo BLI-3 activity promotes the conversion of extracellular DA into toxic reactive species, which, in turn, can be taken up by DAT-1 in DAergic neurons, thus leading to oxidative stress and cell degeneration.
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Lee B, Hiney JK, Pine MD, Srivastava VK, Dees WL. Manganese stimulates luteinizing hormone releasing hormone secretion in prepubertal female rats: hypothalamic site and mechanism of action. J Physiol 2006; 578:765-72. [PMID: 17110411 PMCID: PMC2151346 DOI: 10.1113/jphysiol.2006.123083] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have shown recently that Mn2+ stimulates gonadotropin secretion via an action at the hypothalamic level, and a diet supplemented with a low dose of the element is capable of advancing the time of female puberty. In this study, we used an in vitro approach to investigate the mechanism by which Mn2+ induces luteinizing hormone-releasing hormone (LHRH) secretion from prepubertal female rats. The medial basal hypothalamus from 30-day-old rats was incubated in Locke solution for 30 min to assess basal LHRH secretion, then incubated with buffer alone or buffer plus either a nitric oxide synthase (NOS) inhibitor (N-monomethyl-L-arginine (NMMA); 300 or 500 microM) or a soluble guanylyl cyclase (sGC) inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ); 100 or 250 microM) for another 30 min. Finally, the incubation continued for a further 30 min, but in the presence of MnCl2 (50 or 250 microM) to assess the effect of the blockers on stimulated LHRH secretion. Both 50 and 250 microM MnCl2 stimulated LHRH release (P < 0.05 and P < 0.01, respectively). The addition of 300-500 microM NMMA to the medium did not block Mn2+-stimulated release of LHRH, even with the higher dose of MnCl2. Furthermore, while 50, 100 and 250 microM MnCl2 all significantly induced LHRH release, the two lowest doses did not stimulate total nitrite released from the same tissue, an effect only observed with the highest dose. Taken together, these data suggest that Mn2+ is not an effective stimulator of NO. Conversely, inhibiting sGC with ODQ blocked the Mn2+-stimulated secretion of LHRH in a dose-dependent manner, indicating that GC is the site of action of Mn2+. Additionally, we showed that Mn2+ stimulated cGMP and LHRH from the same tissues, and that downstream blocking of protein kinase G formation with KT5823 (10 microM) inhibited Mn2+-induced LHRH release. These data demonstrate that the principal action of Mn2+ within the hypothalamus is to activate sGC directly and/or as a cofactor with available NO, hence generating cGMP and resulting in prepubertal LHRH release.
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Affiliation(s)
- Boyeon Lee
- Department of Veterinary Medicine, College of Veterinary Medicine, Texas A & M University, College Station, TX 77843-4458, USA
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Zwingmann C, Leibfritz D, Hazell AS. Energy metabolism in astrocytes and neurons treated with manganese: relation among cell-specific energy failure, glucose metabolism, and intercellular trafficking using multinuclear NMR-spectroscopic analysis. J Cereb Blood Flow Metab 2003; 23:756-71. [PMID: 12796724 DOI: 10.1097/01.wcb.0000056062.25434.4d] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A central question in manganese neurotoxicity concerns mitochondrial dysfunction leading to cerebral energy failure. To obtain insight into the underlying mechanism(s), the authors investigated cell-specific pathways of [1-13C]glucose metabolism by high-resolution multinuclear NMR-spectroscopy. Five-day treatment of neurons with 100-micro mol/L MnCl(2) led to 50% and 70% decreases of ATP/ADP and phosphocreatine-creatine ratios, respectively. An impaired flux of [1-13C]glucose through pyruvate dehydrogenase, which was associated with Krebs cycle inhibition and hence depletion of [4-13C]glutamate, [2-13C]GABA, and [13C]glutathione, hindered the ability of neurons to compensate for mitochondrial dysfunction by oxidative glucose metabolism and further aggravated neuronal energy failure. Stimulated glycolysis and oxidative glucose metabolism protected astrocytes against energy failure and oxidative stress, leading to twofold increased de novo synthesis of [3-13C]lactate and fourfold elevated [4-13C]glutamate and [13C]glutathione levels. Manganese, however, inhibited the synthesis and release of glutamine. Comparative NMR data obtained from cocultures showed disturbed astrocytic function and a failure of astrocytes to provide neurons with substrates for energy and neurotransmitter metabolism, leading to deterioration of neuronal antioxidant capacity (decreased glutathione levels) and energy metabolism. The results suggest that, concomitant to impaired neuronal glucose oxidation, changes in astrocytic metabolism may cause a loss of intercellular homeostatic equilibrium, contributing to neuronal dysfunction in manganese neurotoxicity.
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Affiliation(s)
- Claudia Zwingmann
- Department of Medicine, Hôpital Saint-Luc (CHUM), University of Montreal, Montreal, Quebec, Canada
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Tiffany-Castiglion E, Qian Y. Astroglia as metal depots: molecular mechanisms for metal accumulation, storage and release. Neurotoxicology 2001; 22:577-92. [PMID: 11770879 DOI: 10.1016/s0161-813x(01)00050-x] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The brain is an organ that concentrates metals, and these metals are often localized to astroglia. An examination of metal physiology of brain cells, particularly astroglia, offers insights into the developmental neurotoxicity of certain metals, including lead (Pb), mercury (Hg), manganese (Mn), and copper (Cu). Xenobiotic metals probably accumulate in cells by exploiting the normal functions of proteins that transport and handle essential metals. In addition, essential metals may become toxic by accumulating at levels that exceed the normal metal buffering capacity of the cell. This review considers the uptake, accumulation, storage, and release of two xenobiotic metals, Pb and Hg, as well as two essential nutrient metals that are neurotoxic in high amounts, Mn and Cu. Evidence that each metal accumulates in astroglia is evaluated, together with the mechanisms the host cell may invoke to protect itself from cytoxicity.
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Affiliation(s)
- E Tiffany-Castiglion
- Department of Veterinary Anatomy and Public Health, Center for Environmental and Rural Health, Texas A&M University, College Station 77843-4458, USA.
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Ledig M, Copin JC, Tholey G, Leroy M, Rastegar F, Wedler F. Effect of manganese on the development of glial cells cultured from prenatally alcohol exposed rats. Neurochem Res 1995; 20:435-41. [PMID: 7651581 DOI: 10.1007/bf00973099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Maternal alcohol abuse is known to produce retardation in brain maturation and brain functions. Using cultured glial cells as a model system to study these effects of alcohol we found an alcohol antagonizing property for manganese (Mn). Mn was added to the alcohol diet (MnCl2 25 mg/l of 20% v/v ethanol) of pregnant rats. Glial cells were cultured during 4 weeks from cortical brain cells of pups born to these mothers. Several biochemical parameters were examined: protein levels, enzymatic markers of glial cell maturation (enolase and glutamine synthetase), superoxide dismutase a scavenger of free radicals produced during alcohol degradation. The results were compared to appropriate controls. A beneficent effect of Mn was observed for the pups weight which was no more significantly different from the control values. Protein levels, enolase and glutamine synthetase activities were increased mainly during the proliferative period when Mn was added to the alcohol diet compared to the only alcohol treated animals. This Mn effect was not found for superoxide dismutase in cultured glial cells but exists in the total brain of the 2 week-old offspring. In the total 2 and 4 week-old brain the alcohol induced decrease of enolase and glutamine synthetase was also antagonized by the Mn supplementation. Our data suggest that Mn may act as a factor overcoming at least partially some aspects of alcohol induced retardation of nerve cell development.
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Affiliation(s)
- M Ledig
- Laboratoire de Neurobiologie Ontogénique, Centre de Neurochimie du CNRS, Strasbourg, France
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Wedler FC, Vichnin MC, Ley BW, Tholey G, Ledig M, Copin JC. Effects of Ca(II) ions on Mn(II) dynamics in chick glia and rat astrocytes: potential regulation of glutamine synthetase. Neurochem Res 1994; 19:145-51. [PMID: 7910379 DOI: 10.1007/bf00966809] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Previous studies have demonstrated that in glia and astrocytes Mn(II) is distributed with ca. 30-40% in the cytoplasm, 60-70% in mitochondria. Ca(II) ions were observed to alter both the flux rates and distribution of Mn(II) ions in primary cultures of chick glia and rat astrocytes. External (influxing) Ca(II) ions had the greatest effect on Mn(II) uptake and efflux, compared to internal (effluxing) or internal-external equilibrated Ca(II) ions. External (influxing) Ca(II) ions inhibited the net rate and extent of Mn(II) uptake but enhanced Mn(II) efflux from mitochondria. These observations differ from Ca(II)-Mn(II) effects previously reported with "brain" (neuronal) mitochondria. Overall, increased cytoplasmic Ca(II) acts to block Mn(II) uptake and enhance Mn(II) release by mitochondria, which serve to increase the cytoplasmic concentration of free Mn(II). A hypothesis is presented involving external L-glutamate acting through membrane receptors to mobilize cell Ca(II), which in turn causes mitochondrial Mn(II) to be released. Because the concentration of free cytoplasmic Mn(II) is poised near the Kd for Mn(II) with glutamine synthetase, a slight increase in cytoplasmic Mn(II) will directly enhance the activity of glutamine synthetase, which catalyzes removal of neurotoxic glutamate and ammonia.
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Affiliation(s)
- F C Wedler
- Dept. of Molecular & Cell Biology, Althouse Laboratory, Pennsylvania State University, University Park 16802
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Wedler FC. Biological significance of manganese in mammalian systems. PROGRESS IN MEDICINAL CHEMISTRY 1993; 30:89-133. [PMID: 7905650 DOI: 10.1016/s0079-6468(08)70376-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- F C Wedler
- Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802
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Ledig M, Tholey G, Megias-Megias L, Kopp P, Wedler F. Combined effects of ethanol and manganese on cultured neurons and glia. Neurochem Res 1991; 16:591-6. [PMID: 1684408 DOI: 10.1007/bf00974879] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Manganese is essential for normal development and activity of the nervous tissue. Mn2+ ions are involved in protein synthesis and may prevent free radical damage. Since it is now established that alcohol degradation may produce free radicals, we studied the effect of Mn2+ on ethanol induced alterations using cultured nerve cells as an experimental model of the central nervous system. Neurons and glial cells were cultured from rat brain cortex; a tumoral rat glial cell line (C6) was also examined. We measured enzymatic markers of nerve cell maturation (enolase, glutamine synthetase) and superoxide dismutase, a scavenger of free radicals; all these enzymes being activated by Mn2+ ions. Only for the glial cell types an alcohol antagonizing effect was found when Mn2+ was combined with ethanol. Neurons were not sensitive to that Mn2+ effect.
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Affiliation(s)
- M Ledig
- Centre de Neurochimie du CNRS, Strasbourg, France
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