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Malovic E, Ealy A, Hsu PJ, Sarkar S, Miller C, Rokad D, Goeser C, Hartman AK, Zhu A, Palanisamy B, Zenitsky G, Jin H, Anantharam V, Kanthasamy A, He C, Kanthasamy AG. Epitranscriptomic Reader YTHDF2 Regulates SEK1( MAP2K4 )-JNK-cJUN Inflammatory Signaling in Astrocytes during Neurotoxic Stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.26.577106. [PMID: 38328119 PMCID: PMC10849634 DOI: 10.1101/2024.01.26.577106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
As the most abundant glial cells in the CNS, astrocytes dynamically respond to neurotoxic stress, however, the key molecular regulators controlling the inflammatory status of these sentinels during neurotoxic stress have remained elusive. Herein, we demonstrate that the m6A epitranscriptomic mRNA modification tightly regulates the pro-inflammatory functions of astrocytes. Specifically, the astrocytic neurotoxic stresser, manganese (Mn), downregulated the m6A reader YTHDF2 in human and mouse astrocyte cultures and in the mouse brain. Functionally, YTHDF2 knockdown augmented, while its overexpression dampened, neurotoxic stress induced proinflammatory response, suggesting YTHDF2 serves as a key upstream regulator of inflammatory responses in astrocytes. Mechnistically, YTHDF2 RIP-sequencing identified MAP2K4 ( MKK4; SEK1) mRNA as a YTHDF2 target influencing inflammatory signaling. Our target validation revealed Mn-exposed astrocytes mediates proinflammatory response by activating the phosphorylation of SEK1, JNK, and cJUN signaling. Collectively, YTHDF2 serves a key upstream 'molecular switch' controlling SEK1( MAP2K4 )-JNK-cJUN proinflammatory signaling in astrocytes.
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Critical Involvement of Glial Cells in Manganese Neurotoxicity. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1596185. [PMID: 34660781 PMCID: PMC8514895 DOI: 10.1155/2021/1596185] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/16/2021] [Accepted: 09/21/2021] [Indexed: 12/13/2022]
Abstract
Over the years, most of the research concerning manganese exposure was restricted to the toxicity of neuronal cells. Manganese is an essential trace element that in high doses exerts neurotoxic effects. However, in the last two decades, efforts have shifted toward a more comprehensive approach that takes into account the involvement of glial cells in the development of neurotoxicity as a brain insult. Glial cells provide structural, trophic, and metabolic support to neurons. Nevertheless, these cells play an active role in adult neurogenesis, regulation of synaptogenesis, and synaptic plasticity. Disturbances in glial cell function can lead to neurological disorders, including neurodegenerative diseases. This review highlights the pivotal role that glial cells have in manganese-induced neurotoxicity as well as the most sounding mechanisms involved in the development of this phenomenon.
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Sarkar S. Mechanism of Gene-Environment Interactions Driving Glial Activation in Parkinson's Diseases. Curr Environ Health Rep 2021; 8:203-211. [PMID: 34043217 DOI: 10.1007/s40572-021-00320-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE OF REVIEW Parkinson's disease (PD) is the most prevalent motor disorder and is characterized by loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) region of the brain. Though the pathology of PD is well established, the cause of this neuronal loss is not well understood. Approximately 90% of PD cases are sporadic, and the environment plays a significant role in disease pathogenesis. The etiology of PD is highly complex, with neuroinflammation being one of the most critical factors implicated in PD. However, the signaling mechanisms underlying neuroinflammation and its interaction with environmental factors are unclear. RECENT FINDINGS Astroglia and microglia are the two principal cells that play an essential role in maintaining neuronal health in many ways, including through immunological means. Exposure to environmental stressors from various sources affects these glial cells leading to chronic and sustained inflammation. Recent epidemiological studies have identified an interaction among environmental factors and glial genes in Parkinson's disease. Mechanistic studies have shown that exposure to pesticides like rotenone and paraquat, neurotoxic metals like manganese and lead, and even diesel exhaust fumes induce glial activation by regulating various key inflammatory pathways, including the inflammasomes, NOX pathways, and others. This review aims to discuss the recent advances in understanding the mechanism of glial induction in response to environmental stressors and discuss the potential role of gene-environment interaction in driving glial activation.
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Affiliation(s)
- Souvarish Sarkar
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA.
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4
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Ivleva I, Pestereva N, Zubov A, Karpenko M. Intranasal exposure of manganese induces neuroinflammation and disrupts dopamine metabolism in the striatum and hippocampus. Neurosci Lett 2020; 738:135344. [PMID: 32889006 DOI: 10.1016/j.neulet.2020.135344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/18/2020] [Accepted: 08/27/2020] [Indexed: 01/26/2023]
Abstract
Prolonged exposure to manganese (Mn) may lead to toxic effects on the central nervous system (CNS). The mechanisms underlying neuronal death from exposure to Mn are not well understood but undoubtedly involve inflammatory processes. The aim of this study was to explore the effects of long-lasting intranasal Mn exposure in rats focusing on inflammatory processes and catecholamine (dopamine, norepinephrine) levels in the striatum and hippocampus. It was found that intranasal administration by instillation of MnCl2 solution once a day for 90 days leads to impaired movement and gait. We also observed that Mn concentration increased in the hippocampus (by 30 %) and in the striatum (by 220 %), dopamine (24 %) and DOPAC (35 %) were reduced in the striatum, and dopamine (190 %) and DOPAC (220 %) levels increased with simultaneously norepinephrine reduction (30 %) in the hippocampus. Observation of cytokine mRNA revealed increased expression of both assayed cytokines (IL-1β and TNF-α) in the hippocampus. There was a 3-fold increase in the expression of IBA-1 mRNA, 2-fold increase in NFκB mRNA, and dramatic reduction in IkB mRNA in the striatum. Taken together, intranasal exposure to a high dose of MnCl2 induces neuroinflammation and neurotransmission disturbance, but the effects are specific for each studied brain region.
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Affiliation(s)
- Irina Ivleva
- Department of Physiology (Pavlov's), Institute of Experimental Medicine, St. Petersburg, Russia.
| | - Nina Pestereva
- Department of Physiology (Pavlov's), Institute of Experimental Medicine, St. Petersburg, Russia
| | - Alexander Zubov
- Department of Physiology (Pavlov's), Institute of Experimental Medicine, St. Petersburg, Russia
| | - Marina Karpenko
- Department of Physiology (Pavlov's), Institute of Experimental Medicine, St. Petersburg, Russia; Institute of Physics, Nanotechnology and Telecommunications, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
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Mechanism of Manganese Dysregulation of Dopamine Neuronal Activity. J Neurosci 2020; 40:5871-5891. [PMID: 32576620 DOI: 10.1523/jneurosci.2830-19.2020] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 01/01/2023] Open
Abstract
Manganese exposure produces Parkinson's-like neurologic symptoms, suggesting a selective dysregulation of dopamine transmission. It is unknown, however, how manganese accumulates in dopaminergic brain regions or how it regulates the activity of dopamine neurons. Our in vivo studies in male C57BLJ mice suggest that manganese accumulates in dopamine neurons of the VTA and substantia nigra via nifedipine-sensitive Ca2+ channels. Manganese produces a Ca2+ channel-mediated current, which increases neurotransmitter release and rhythmic firing activity of dopamine neurons. These increases are prevented by blockade of Ca2+ channels and depend on downstream recruitment of Ca2+-activated potassium channels to the plasma membrane. These findings demonstrate the mechanism of manganese-induced dysfunction of dopamine neurons, and reveal a potential therapeutic target to attenuate manganese-induced impairment of dopamine transmission.SIGNIFICANCE STATEMENT Manganese is a trace element critical to many physiological processes. Overexposure to manganese is an environmental risk factor for neurologic disorders, such as a Parkinson's disease-like syndrome known as manganism. We found that manganese concentration-dependently increased the excitability of dopamine neurons, decreased the amplitude of action potentials, and narrowed action potential width. Blockade of Ca2+ channels prevented these effects as well as manganese accumulation in the mouse midbrain in vivo Our data provide a potential mechanism for manganese regulation of dopaminergic neurons.
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Hernroth B, Tassidis H, Baden SP. Immunosuppression of aquatic organisms exposed to elevated levels of manganese: From global to molecular perspective. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 104:103536. [PMID: 31705914 DOI: 10.1016/j.dci.2019.103536] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/03/2019] [Indexed: 06/10/2023]
Abstract
Manganese (Mn) is an essential trace metal for all organisms. However, in excess it causes toxic effects but the impact on aquatic environments has so far been highly overlooked. Manganese is abundant both in costal and deep sea sediments and becomes bioavailable (Mn2+) during redox conditions. This is an increasing phenomenon due to eutrophication-induced hypoxia and aggravated through the ongoing climate change. Intracellular accumulation of Mn2+ causes oxidative stress and activates evolutionary conserved pathways inducing apoptosis and cell cycle arrest. Here, studies are compiled on how excess of dissolved Mn suppresses the immune system of various aquatic organisms by adversely affecting both renewal of immunocytes and their functionality, such as phagocytosis and activation of pro-phenoloxidase. These impairments decrease the animal's bacteriostatic capacity, indicating higher susceptibility to infections. Increased distribution of pathogens, which is believed to accompany climate change, requires preserved immune sentinel functions and Mn can be crucial for the outcome of host-pathogen interactions.
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Affiliation(s)
- Bodil Hernroth
- Department of Natural Science, Kristianstad University, SE-291 88, Kristianstad, Sweden; The Royal Swedish Academy of Sciences, Kristineberg Marine Research Station, SE-450 34, Fiskebäckskil, Sweden.
| | - Helena Tassidis
- Department of Natural Science, Kristianstad University, SE-291 88, Kristianstad, Sweden
| | - Susanne P Baden
- Department of Biological and Environmental Sciences, University of Gothenburg, Kristineberg Marine Research Station, SE-45034, Fiskebäckskil, Sweden
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Ijomone OM, Aluko OM, Okoh COA, Martins AC, Aschner M. Role for calcium signaling in manganese neurotoxicity. J Trace Elem Med Biol 2019; 56:146-155. [PMID: 31470248 DOI: 10.1016/j.jtemb.2019.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Calcium is an essential macronutrient that is involved in many cellular processes. Homeostatic control of intracellular levels of calcium ions [Ca2+] is vital to maintaining cellular structure and function. Several signaling molecules are involved in regulating Ca2+ levels in cells and perturbation of calcium signaling processes is implicated in several neurodegenerative and neurologic conditions. Manganese [Mn] is a metal which is essential for basic physiological functions. However, overexposure to Mn from environmental contamination and workplace hazards is a global concern. Mn overexposure leads to its accumulation in several human organs particularly the brain. Mn accumulation in the brain results in a manganism, a Parkinsonian-like syndrome. Additionally, Mn is a risk factor for several neurodegenerative diseases including Parkinson's disease and Alzheimer's disease. Mn neurotoxicity also affects several neurotransmitter systems including dopaminergic, cholinergic and GABAergic. The mechanisms of Mn neurotoxicity are still being elucidated. AIM The review will highlight a potential role for calcium signaling molecules in the mechanisms of Mn neurotoxicity. CONCLUSION Ca2+ regulation influences the neurodegenerative process and there is possible role for perturbed calcium signaling in Mn neurotoxicity. Mechanisms implicated in Mn-induced neurodegeneration include oxidative stress, generation of free radicals, and apoptosis. These are influenced by mitochondrial integrity which can be dependent on intracellular Ca2+ homeostasis. Nevertheless, further elucidation of the direct effects of calcium signaling dysfunction and calcium-binding proteins activities in Mn neurotoxicity is required.
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Affiliation(s)
- Omamuyovwi M Ijomone
- The Neuro- Lab, Department of Human Anatomy, Federal University of Technology Akure, Ondo, Nigeria.
| | - Oritoke M Aluko
- Department of Physiology, Federal University of Technology Akure, Ondo, Nigeria
| | - Comfort O A Okoh
- The Neuro- Lab, Department of Human Anatomy, Federal University of Technology Akure, Ondo, Nigeria
| | - Airton Cunha Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States.
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Fernandes J, Chandler JD, Lili LN, Uppal K, Hu X, Hao L, Go YM, Jones DP. Transcriptome Analysis Reveals Distinct Responses to Physiologic versus Toxic Manganese Exposure in Human Neuroblastoma Cells. Front Genet 2019; 10:676. [PMID: 31396262 PMCID: PMC6668488 DOI: 10.3389/fgene.2019.00676] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/27/2019] [Indexed: 12/16/2022] Open
Abstract
Manganese (Mn) is an essential trace element, which also causes neurotoxicity in exposed occupational workers. Mn causes mitochondrial toxicity; however, little is known about transcriptional responses discriminated by physiological and toxicological levels of Mn. Identification of such mechanisms could provide means to evaluate risk of Mn toxicity and also potential avenues to protect against adverse effects. To study the Mn dose-response effects on transcription, analyzed by RNA-Seq, we used human SH-SY5Y neuroblastoma cells exposed for 5 h to Mn (0 to 100 μM), a time point where no immediate cell death occurred at any of the doses. Results showed widespread effects on abundance of protein-coding genes for metabolism of reactive oxygen species, energy sensing, glycolysis, and protein homeostasis including the unfolded protein response and transcriptional regulation. Exposure to a concentration (10 μM Mn for 5 h) that did not result in cell death after 24-h increased abundance of differentially expressed genes (DEGs) in the protein secretion pathway that function in protein trafficking and cellular homeostasis. These include BET1 (Golgi vesicular membrane-trafficking protein), ADAM10 (ADAM metallopeptidase domain 10), and ARFGAP3 (ADP-ribosylation factor GTPase-activating protein 3). In contrast, 5-h exposure to 100 μM Mn, a concentration that caused cell death after 24 h, increased abundance of DEGs for components of the mitochondrial oxidative phosphorylation pathway. Integrated pathway analysis results showed that protein secretion gene set was associated with amino acid metabolites in response to 10 μM Mn, while oxidative phosphorylation gene set was associated with energy, lipid, and neurotransmitter metabolites at 100 μM Mn. These results show that differential effects of Mn occur at a concentration which does not cause subsequent cell death compared to a concentration that causes subsequent cell death. If these responses translate to effects on the secretory pathway and mitochondrial functions in vivo, differential activities of these systems could provide a sensitive basis to discriminate sub-toxic and toxic environmental and occupational Mn exposures.
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Affiliation(s)
| | | | | | | | | | | | - Young-Mi Go
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Dean P. Jones
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University, Atlanta, GA, United States
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Synchrotron radiation-based FTIR spectro-microscopy of the brainstem of the hSOD1 G93A rat model of amyotrophic lateral sclerosis. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:475-484. [PMID: 31243482 DOI: 10.1007/s00249-019-01380-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 04/28/2019] [Accepted: 06/17/2019] [Indexed: 10/26/2022]
Abstract
Pathological mechanisms in amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, are still poorly understood. One subset of familial ALS cases is caused by mutations in the metallo-enzyme copper-zinc superoxide dismutase (SOD1), increasing the susceptibility of the SOD1 protein to form insoluble intracellular aggregates. Here, we employed synchrotron radiation-based Fourier transform infrared spectroscopy and microscopy to investigate brainstem cross-sections from the transgenic hSOD1 G93A rat model of ALS that overexpresses human-mutated SOD1. We compared the biomacromolecular organic composition in brainstem tissue cross-sections of ALS rats and their non-transgenic littermates (NTg). We demonstrate that the proteins and especially their antiparallel β-sheet structure significantly differed in all three regions: the facial nucleus (FN), the gigantocellular reticular nucleus (GRN) and the trigeminal motor nucleus (TMN) in the brainstem tissue of ALS rats. The protein levels varied between different brainstem areas, with the highest concentration observed in the region of the FN in the brainstem tissue of NTg animals. Furthermore, the concentration of lipids and esters was significantly decreased in the TMN and FN of ALS animals. A similar pattern was detected for choline and phosphate assigned to nucleic acids with the highest concentrations in the FN of NTg animals. The spectroscopic analysis showed significant differences in phosphates, amide and lipid structure in the FN of NTg animals in comparison with the same area of ALS rats. These results show that the hG93A SOD1 mutation causes metabolic cellular changes and point to a link between bioorganic composition and hallmarks of protein aggregation.
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Dučić T, Stamenković S, Lai B, Andjus P, Lučić V. Multimodal Synchrotron Radiation Microscopy of Intact Astrocytes from the hSOD1 G93A Rat Model of Amyotrophic Lateral Sclerosis. Anal Chem 2018; 91:1460-1471. [DOI: 10.1021/acs.analchem.8b04273] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Tanja Dučić
- CELLS − ALBA, Carrer de la Llum 2-26, 08290 Cerdanyola del Vallès, Barcelona, Spain
| | - Stefan Stamenković
- Faculty of Biology, University of Belgrade, Center for Laser Microscopy−CLM, Studentski Trg 3, 11000 Belgrade, Serbia
| | - Barry Lai
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Pavle Andjus
- Faculty of Biology, University of Belgrade, Center for Laser Microscopy−CLM, Studentski Trg 3, 11000 Belgrade, Serbia
| | - Vladan Lučić
- Max Planck Institute of Biochemistry, Am Klopferspitz 1, 82152, Martinsried, Germany
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11
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Affiliation(s)
- Jiao Li
- Department of Hygiene Toxicology, School of Public Health, Zunyi Medical College, Zunyi, P.R. China
- The second people’s Hospital of Qixingguan District, Bijie, Guizhou, P.R. China
| | - Yuyan Cen
- Department of Hygiene Toxicology, School of Public Health, Zunyi Medical College, Zunyi, P.R. China
| | - Yan Li
- Department of Hygiene Toxicology, School of Public Health, Zunyi Medical College, Zunyi, P.R. China
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12
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Belkacemi T, Niermann A, Hofmann L, Wissenbach U, Birnbaumer L, Leidinger P, Backes C, Meese E, Keller A, Bai X, Scheller A, Kirchhoff F, Philipp SE, Weissgerber P, Flockerzi V, Beck A. TRPC1- and TRPC3-dependent Ca 2+ signaling in mouse cortical astrocytes affects injury-evoked astrogliosis in vivo. Glia 2017. [PMID: 28636132 DOI: 10.1002/glia.23180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Following brain injury astrocytes change into a reactive state, proliferate and grow into the site of lesion, a process called astrogliosis, initiated and regulated by changes in cytoplasmic Ca2+ . Transient receptor potential canonical (TRPC) channels may contribute to Ca2+ influx but their presence and possible function in astrocytes is not known. By RT-PCR and RNA sequencing we identified transcripts of Trpc1, Trpc2, Trpc3, and Trpc4 in FACS-sorted glutamate aspartate transporter (GLAST)-positive cultured mouse cortical astrocytes and subcloned full-length Trpc1 and Trpc3 cDNAs from these cells. Ca2+ entry in cortical astrocytes depended on TRPC3 and was increased in the absence of Trpc1. After co-expression of Trpc1 and Trpc3 in HEK-293 cells both proteins co-immunoprecipitate and form functional heteromeric channels, with TRPC1 reducing TRPC3 activity. In vitro, lack of Trpc3 reduced astrocyte proliferation and migration whereas the TRPC3 gain-of-function moonwalker mutation and Trpc1 deficiency increased astrocyte migration. In vivo, astrogliosis and cortex edema following stab wound injury were reduced in Trpc3-/- but increased in Trpc1-/- mice. In summary, our results show a decisive contribution of TRPC3 to astrocyte Ca2+ signaling, which is even augmented in the absence of Trpc1, in particular following brain injury. Targeted therapies to reduce TRPC3 channel activity in astrocytes might therefore be beneficial in traumatic brain injury.
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Affiliation(s)
- Thabet Belkacemi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Alexander Niermann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Laura Hofmann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Ulrich Wissenbach
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA.,Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, C1107AFF, Argentina
| | | | - Christina Backes
- Klinische Bioinformatik, Universität des Saarlandes, Saarbrücken, 66123, Germany
| | - Eckart Meese
- Institut für Humangenetik, Homburg, 66421, Germany
| | - Andreas Keller
- Klinische Bioinformatik, Universität des Saarlandes, Saarbrücken, 66123, Germany
| | - Xianshu Bai
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Anja Scheller
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Frank Kirchhoff
- Molekulare Physiologie, Universität des Saarlandes, Homburg, 66421, Germany
| | - Stephan E Philipp
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Petra Weissgerber
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany
| | - Andreas Beck
- Experimentelle und Klinische Pharmakologie und Toxikologie, Homburg, 66421, Germany.,Zentrum für Human- und Molekularbiologie, Homburg, 66421, Germany
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13
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Sarkar S, Malovic E, Harischandra DS, Ngwa HA, Ghosh A, Hogan C, Rokad D, Zenitsky G, Jin H, Anantharam V, Kanthasamy AG, Kanthasamy A. Manganese exposure induces neuroinflammation by impairing mitochondrial dynamics in astrocytes. Neurotoxicology 2017; 64:204-218. [PMID: 28539244 DOI: 10.1016/j.neuro.2017.05.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/19/2017] [Accepted: 05/19/2017] [Indexed: 12/21/2022]
Abstract
Chronic manganese (Mn) exposure induces neurotoxicity, which is characterized by Parkinsonian symptoms resulting from impairment in the extrapyramidal motor system of the basal ganglia. Mitochondrial dysfunction and oxidative stress are considered key pathophysiological features of Mn neurotoxicity. Recent evidence suggests astrocytes as a major target of Mn neurotoxicity since Mn accumulates predominantly in astrocytes. However, the primary mechanisms underlying Mn-induced astroglial dysfunction and its role in metal neurotoxicity are not completely understood. In this study, we examined the interrelationship between mitochondrial dysfunction and astrocytic inflammation in Mn neurotoxicity. We first evaluated whether Mn exposure alters mitochondrial bioenergetics in cultured astrocytes. Metabolic activity assessed by MTS assay revealed an IC50 of 92.68μM Mn at 24h in primary mouse astrocytes (PMAs) and 50.46μM in the human astrocytic U373 cell line. Mn treatment reduced mitochondrial mass, indicative of impaired mitochondrial function and biogenesis, which was substantiated by the significant reduction in mRNA of mitofusin-2, a protein that serves as a ubiquitination target for mitophagy. Furthermore, Mn increased mitochondrial circularity indicating augmented mitochondrial fission. Seahorse analysis of bioenergetics status in Mn-treated astrocytes revealed that Mn significantly impaired the basal mitochondrial oxygen consumption rate as well as the ATP-linked respiration rate. The effect of Mn on mitochondrial energy deficits was further supported by a reduction in ATP production. Mn-exposed primary astrocytes also exhibited a severely quiescent energy phenotype, which was substantiated by the inability of oligomycin to increase the extracellular acidification rate. Since astrocytes regulate immune functions in the CNS, we also evaluated whether Mn modulates astrocytic inflammation. Mn exposure in astrocytes not only stimulated the release of proinflammatory cytokines, but also exacerbated the inflammatory response induced by aggregated α-synuclein. The novel mitochondria-targeted antioxidant, mito-apocynin, significantly attenuated Mn-induced inflammatory gene expression, further supporting the role of mitochondria dysfunction and oxidative stress in mediating astrogliosis. Lastly, intranasal delivery of Mn in vivo elevated GFAP and depressed TH levels in the olfactory bulbs, clearly supporting the involvement of astrocytes in Mn-induced dopaminergic neurotoxicity. Collectively, our study demonstrates that Mn drives proinflammatory events in astrocytes by impairing mitochondrial bioenergetics.
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Affiliation(s)
- Souvarish Sarkar
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Emir Malovic
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Dilshan S Harischandra
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Hilary A Ngwa
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Anamitra Ghosh
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Colleen Hogan
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Dharmin Rokad
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Gary Zenitsky
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Huajun Jin
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Vellareddy Anantharam
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Anumantha G Kanthasamy
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States
| | - Arthi Kanthasamy
- Parkinson Disorders Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, 2062 Veterinary Medicine Building, Iowa State University, Ames, IA 50011, United States.
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14
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Inflammatory Activation of Microglia and Astrocytes in Manganese Neurotoxicity. ADVANCES IN NEUROBIOLOGY 2017; 18:159-181. [PMID: 28889267 DOI: 10.1007/978-3-319-60189-2_8] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurotoxicity due to excessive exposure to manganese (Mn) has been described as early as 1837 (Couper, Br Ann Med Pharm Vital Stat Gen Sci 1:41-42, 1837). Extensive research over the past two decades has revealed that Mn-induced neurological injury involves complex pathophysiological signaling mechanisms between neurons and glial cells. Glial cells are an important target of Mn in the brain, both for sequestration of the metal, as well as for activating inflammatory signaling pathways that damage neurons through overproduction of numerous reactive oxygen and nitrogen species and inflammatory cytokines. Understanding how these pathways are regulated in glial cells during Mn exposure is critical to determining the mechanisms underlying permanent neurological dysfunction stemming from excess exposure. The subject of this review will be to delineate mechanisms by which Mn interacts with glial cells to perturb neuronal function, with a particular emphasis on neuroinflammation and neuroinflammatory signaling between distinct populations of glial cells.
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"Manganese-induced neurotoxicity: a review of its behavioral consequences and neuroprotective strategies". BMC Pharmacol Toxicol 2016; 17:57. [PMID: 27814772 PMCID: PMC5097420 DOI: 10.1186/s40360-016-0099-0] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 10/19/2016] [Indexed: 01/20/2023] Open
Abstract
Manganese (Mn) is an essential heavy metal. However, Mn’s nutritional aspects are paralleled by its role as a neurotoxicant upon excessive exposure. In this review, we covered recent advances in identifying mechanisms of Mn uptake and its molecular actions in the brain as well as promising neuroprotective strategies. The authors focused on reporting findings regarding Mn transport mechanisms, Mn effects on cholinergic system, behavioral alterations induced by Mn exposure and studies of neuroprotective strategies against Mn intoxication. We report that exposure to Mn may arise from environmental sources, occupational settings, food, total parenteral nutrition (TPN), methcathinone drug abuse or even genetic factors, such as mutation in the transporter SLC30A10. Accumulation of Mn occurs mainly in the basal ganglia and leads to a syndrome called manganism, whose symptoms of cognitive dysfunction and motor impairment resemble Parkinson’s disease (PD). Various neurotransmitter systems may be impaired due to Mn, especially dopaminergic, but also cholinergic and GABAergic. Several proteins have been identified to transport Mn, including divalent metal tranporter-1 (DMT-1), SLC30A10, transferrin and ferroportin and allow its accumulation in the central nervous system. Parallel to identification of Mn neurotoxic properties, neuroprotective strategies have been reported, and these include endogenous antioxidants (for instance, vitamin E), plant extracts (complex mixtures containing polyphenols and non-characterized components), iron chelating agents, precursors of glutathione (GSH), and synthetic compounds that can experimentally afford protection against Mn-induced neurotoxicity.
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Potential Role of Epigenetic Mechanism in Manganese Induced Neurotoxicity. BIOMED RESEARCH INTERNATIONAL 2016; 2016:2548792. [PMID: 27314012 PMCID: PMC4899583 DOI: 10.1155/2016/2548792] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/08/2016] [Indexed: 02/07/2023]
Abstract
Manganese is a vital nutrient and is maintained at an optimal level (2.5–5 mg/day) in human body. Chronic exposure to manganese is associated with neurotoxicity and correlated with the development of various neurological disorders such as Parkinson's disease. Oxidative stress mediated apoptotic cell death has been well established mechanism in manganese induced toxicity. Oxidative stress has a potential to alter the epigenetic mechanism of gene regulation. Epigenetic insight of manganese neurotoxicity in context of its correlation with the development of parkinsonism is poorly understood. Parkinson's disease is characterized by the α-synuclein aggregation in the form of Lewy bodies in neuronal cells. Recent findings illustrate that manganese can cause overexpression of α-synuclein. α-Synuclein acts epigenetically via interaction with histone proteins in regulating apoptosis. α-Synuclein also causes global DNA hypomethylation through sequestration of DNA methyltransferase in cytoplasm. An individual genetic difference may also have an influence on epigenetic susceptibility to manganese neurotoxicity and the development of Parkinson's disease. This review presents the current state of findings in relation to role of epigenetic mechanism in manganese induced neurotoxicity, with a special emphasis on the development of Parkinson's disease.
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Dučić T, Carboni E, Lai B, Chen S, Michalke B, Lázaro DF, Outeiro TF, Bähr M, Barski E, Lingor P. Alpha-Synuclein Regulates Neuronal Levels of Manganese and Calcium. ACS Chem Neurosci 2015; 6:1769-79. [PMID: 26284970 DOI: 10.1021/acschemneuro.5b00093] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Manganese (Mn) may foster aggregation of alpha-synuclein (αSyn) contributing to the pathogenesis of PD. Here, we examined the influence of αSyn overexpression on distribution and oxidation states of Mn in frozen-hydrated primary midbrain neurons (PMNs) by synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near edge structure spectroscopy (XANES). Overexpression of αSyn increased intracellular Mn levels, whereas levels of Ca, Zn, K, P, and S were significantly decreased. Mn oxidation states were not altered. A strong correlation between Cu-/Mn-levels as well as Fe-/Mn-levels was observed in αSyn-overexpressing cells. Subcellular resolution revealed a punctate or filament-like perinuclear and neuritic distribution of Mn, which resembled the expression of DMT1 and MnSOD. While overexpression of αSyn did not significantly alter the expression patterns of the most-expressed Mn transport proteins (DMT1, VGCC, Fpn1), it attenuated the Mn release from Mn-treated neurons. Thus, these data suggest that αSyn may act as an intracellular Mn store. In total, neurotoxicity in PD could be mediated via regulation of transition metal levels and the metal-binding capacity of αSyn, which could represent a promising therapeutic target for this neurodegenerative disorder.
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Affiliation(s)
- Tanja Dučić
- CELLS
−
ALBA, Carretera BP 1413, de Cerdanyola
del Vallès a Sant Cugat del Vallè, km. 33, 08290 Cerdanyola del Vallès,
Barcelona, Spain
| | - Eleonora Carboni
- Department
of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
- DFG-Research Center
for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
| | - Barry Lai
- Advanced
Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States,
| | - Si Chen
- Advanced
Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States,
| | - Bernhard Michalke
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Diana F. Lázaro
- Department
of Neurodegeneration and Restorative Research, University Medicine Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Tiago F. Outeiro
- Department
of Neurodegeneration and Restorative Research, University Medicine Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Mathias Bähr
- Department
of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
- DFG-Research Center
for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
| | - Elisabeth Barski
- Department
of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Paul Lingor
- Department
of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
- DFG-Research Center
for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
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Samsel A, Seneff S. Glyphosate, pathways to modern diseases III: Manganese, neurological diseases, and associated pathologies. Surg Neurol Int 2015; 6:45. [PMID: 25883837 PMCID: PMC4392553 DOI: 10.4103/2152-7806.153876] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/21/2015] [Indexed: 12/20/2022] Open
Abstract
Manganese (Mn) is an often overlooked but important nutrient, required in small amounts for multiple essential functions in the body. A recent study on cows fed genetically modified Roundup(®)-Ready feed revealed a severe depletion of serum Mn. Glyphosate, the active ingredient in Roundup(®), has also been shown to severely deplete Mn levels in plants. Here, we investigate the impact of Mn on physiology, and its association with gut dysbiosis as well as neuropathologies such as autism, Alzheimer's disease (AD), depression, anxiety syndrome, Parkinson's disease (PD), and prion diseases. Glutamate overexpression in the brain in association with autism, AD, and other neurological diseases can be explained by Mn deficiency. Mn superoxide dismutase protects mitochondria from oxidative damage, and mitochondrial dysfunction is a key feature of autism and Alzheimer's. Chondroitin sulfate synthesis depends on Mn, and its deficiency leads to osteoporosis and osteomalacia. Lactobacillus, depleted in autism, depend critically on Mn for antioxidant protection. Lactobacillus probiotics can treat anxiety, which is a comorbidity of autism and chronic fatigue syndrome. Reduced gut Lactobacillus leads to overgrowth of the pathogen, Salmonella, which is resistant to glyphosate toxicity, and Mn plays a role here as well. Sperm motility depends on Mn, and this may partially explain increased rates of infertility and birth defects. We further reason that, under conditions of adequate Mn in the diet, glyphosate, through its disruption of bile acid homeostasis, ironically promotes toxic accumulation of Mn in the brainstem, leading to conditions such as PD and prion diseases.
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Affiliation(s)
- Anthony Samsel
- Research Scientist and Consultant, Deerfield, NH 03037, USA
| | - Stephanie Seneff
- Spoken Language Systems Group, Computer Science and Artificial Intelligence Laboratory, MIT, Cambridge MA 02139, USA
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Streifel KM, Gonzales AL, De Miranda B, Mouneimne R, Earley S, Tjalkens R. Dopaminergic neurotoxicants cause biphasic inhibition of purinergic calcium signaling in astrocytes. PLoS One 2014; 9:e110996. [PMID: 25365260 PMCID: PMC4217743 DOI: 10.1371/journal.pone.0110996] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 09/27/2014] [Indexed: 11/18/2022] Open
Abstract
Dopaminergic nuclei in the basal ganglia are highly sensitive to damage from oxidative stress, inflammation, and environmental neurotoxins. Disruption of adenosine triphosphate (ATP)-dependent calcium (Ca2+) transients in astrocytes may represent an important target of such stressors that contributes to neuronal injury by disrupting critical Ca2+-dependent trophic functions. We therefore postulated that plasma membrane cation channels might be a common site of inhibition by structurally distinct cationic neurotoxicants that could modulate ATP-induced Ca2+ signals in astrocytes. To test this, we examined the capacity of two dopaminergic neurotoxicants to alter ATP-dependent Ca2+ waves and transients in primary murine striatal astrocytes: MPP+, the active metabolite of 1-methyl 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and 6-hydroxydopamine (6-OHDA). Both compounds acutely decreased ATP-induced Ca2+ transients and waves in astrocytes and blocked OAG-induced Ca2+ influx at micromolar concentrations, suggesting the transient receptor potential channel, TRPC3, as an acute target. MPP+ inhibited 1-oleoyl-2-acetyl-sn-glycerol (OAG)-induced Ca2+ transients similarly to the TRPC3 antagonist, pyrazole-3, whereas 6-OHDA only partly suppressed OAG-induced transients. RNAi directed against TRPC3 inhibited the ATP-induced transient as well as entry of extracellular Ca2+, which was augmented by MPP+. Whole-cell patch clamp experiments in primary astrocytes and TRPC3-overexpressing cells demonstrated that acute application of MPP+ completely blocked OAG-induced TRPC3 currents, whereas 6-OHDA only partially inhibited OAG currents. These findings indicate that MPP+ and 6-OHDA inhibit ATP-induced Ca2+ signals in astrocytes in part by interfering with purinergic receptor mediated activation of TRPC3, suggesting a novel pathway in glia that could contribute to neurotoxic injury.
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Affiliation(s)
- Karin M. Streifel
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado, United States of America
| | - Albert L. Gonzales
- Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Briana De Miranda
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado, United States of America
| | - Rola Mouneimne
- Department of Veterinary Integrative Biosciences, Texas A & M University, College Station, Texas, United States of America
| | - Scott Earley
- Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ronald Tjalkens
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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Bakthavatsalam S, Das Sharma S, Sonawane M, Thirumalai V, Datta A. A zebrafish model of manganism reveals reversible and treatable symptoms that are independent of neurotoxicity. Dis Model Mech 2014; 7:1239-51. [PMID: 25261567 PMCID: PMC4213728 DOI: 10.1242/dmm.016683] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Manganese (manganese ion; referred to as Mn) is essential for neuronal function, yet it is toxic at high concentrations. Environmental and occupational exposure to high concentrations of Mn causes manganism, a well-defined movement disorder in humans, with symptoms resembling Parkinson's disease (PD). However, manganism is distinct from PD and the neural basis of its pathology is poorly understood. To address this issue, we generated a zebrafish model of manganism by incubating larvae in rearing medium containing Mn. We find that Mn-treated zebrafish larvae exhibit specific postural and locomotor defects. Larvae begin to float on their sides, show a curved spine and swim in circles. We discovered that treatment with Mn causes postural defects by interfering with mechanotransduction at the neuromasts. Furthermore, we find that the circling locomotion could be caused by long-duration bursting in the motor neurons, which can lead to long-duration tail bends in the Mn-treated larvae. Mn-treated larvae also exhibited fewer startle movements. Additionally, we show that the intensity of tyrosine hydroxylase immunoreactivity is reversibly reduced after Mn-treatment. This led us to propose that reduced dopamine neuromodulation drives the changes in startle movements. To test this, when we supplied an external source of dopamine to Mn-treated larvae, the larvae exhibited a normal number of startle swims. Taken together, these results indicate that Mn interferes with neuronal function at the sensory, motor and modulatory levels, and open avenues for therapeutically targeted studies on the zebrafish model of manganism.
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Affiliation(s)
- Subha Bakthavatsalam
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai-400005, India
| | - Shreya Das Sharma
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore-560065, India
| | - Mahendra Sonawane
- Department of Biological Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai-400005, India
| | - Vatsala Thirumalai
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore-560065, India.
| | - Ankona Datta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai-400005, India.
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Physiological Function and Characterization of TRPCs in Neurons. Cells 2014; 3:455-75. [PMID: 24852263 PMCID: PMC4092863 DOI: 10.3390/cells3020455] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 04/22/2014] [Accepted: 05/13/2014] [Indexed: 12/14/2022] Open
Abstract
Ca2+ entry is essential for regulating vital physiological functions in all neuronal cells. Although neurons are engaged in multiple modes of Ca2+ entry that regulates variety of neuronal functions, we will only discuss a subset of specialized Ca2+-permeable non-selective Transient Receptor Potential Canonical (TRPC) channels and summarize their physiological and pathological role in these excitable cells. Depletion of endoplasmic reticulum (ER) Ca2+ stores, due to G-protein coupled receptor activation, has been shown to activate TRPC channels in both excitable and non-excitable cells. While all seven members of TRPC channels are predominately expressed in neuronal cells, the ion channel properties, mode of activation, and their physiological responses are quite distinct. Moreover, many of these TRPC channels have also been suggested to be associated with neuronal development, proliferation and differentiation. In addition, TRPCs also regulate neurosecretion, long-term potentiation and synaptic plasticity. Similarly, perturbations in Ca2+ entry via the TRPC channels have been also suggested in a spectrum of neuropathological conditions. Hence, understanding the precise involvement of TRPCs in neuronal function and in neurodegenerative conditions would presumably unveil avenues for plausible therapeutic interventions for these devastating neuronal diseases.
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