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Nunes MJ, Carvalho AN, Sá-Lemos C, Colaço M, Cervenka I, Ciraci V, Santos SG, Ribeiro MM, Castanheira M, Jannig PR, Gama MJ, Castro-Caldas M, Rodrigues CMP, Rodrigues E, Ruas JL. Sustained PGC-1α2 or PGC-1α3 expression induces astrocyte dysfunction and degeneration. Eur J Cell Biol 2024; 103:151377. [PMID: 38006841 DOI: 10.1016/j.ejcb.2023.151377] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/27/2023] Open
Abstract
Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) transcriptional coactivators are key regulators of energy metabolism-related genes and are expressed in energy-demanding tissues. There are several PGC-1α variants with different biological functions in different tissues. The brain is one of the tissues where the role of PGC-1α isoforms remains less explored. Here, we used a toxin-based mouse model of Parkinson's disease (PD) and observed that the expression levels of variants PGC-1α2 and PGC-1α3 in the nigrostriatal pathway increases at the onset of dopaminergic cell degeneration. This increase occurs concomitant with an increase in glial fibrillary acidic protein levels. Since PGC-1α coactivators regulate cellular adaptive responses, we hypothesized that they could be involved in the modulation of astrogliosis induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Therefore, we analysed the transcriptome of astrocytes transduced with expression vectors encoding PGC-1α1 to 1α4 by massively parallel sequencing (RNA-seq) and identified the main cellular pathways controlled by these isoforms. Interestingly, in reactive astrocytes the inflammatory and antioxidant responses, adhesion, migration, and viability were altered by PGC-1α2 and PGC-1α3, showing that sustained expression of these isoforms induces astrocyte dysfunction and degeneration. This work highlights PGC-1α isoforms as modulators of astrocyte reactivity and as potential therapeutic targets for the treatment of PD and other neurodegenerative disorders.
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Affiliation(s)
- M J Nunes
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - A N Carvalho
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - C Sá-Lemos
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - M Colaço
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - I Cervenka
- Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, Stockholm, Sweden
| | - V Ciraci
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - S G Santos
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - M M Ribeiro
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - M Castanheira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - P R Jannig
- Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, Stockholm, Sweden
| | - M J Gama
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - M Castro-Caldas
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; UCIBIO, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - C M P Rodrigues
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - E Rodrigues
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - J L Ruas
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, Stockholm, Sweden.
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2
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Yildirim-Balatan C, Fenyi A, Besnault P, Gomez L, Sepulveda-Diaz JE, Michel PP, Melki R, Hunot S. Parkinson's disease-derived α-synuclein assemblies combined with chronic-type inflammatory cues promote a neurotoxic microglial phenotype. J Neuroinflammation 2024; 21:54. [PMID: 38383421 PMCID: PMC10882738 DOI: 10.1186/s12974-024-03043-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/12/2024] [Indexed: 02/23/2024] Open
Abstract
Parkinson's disease (PD) is a common age-related neurodegenerative disorder characterized by the aggregation of α-Synuclein (αSYN) building up intraneuronal inclusions termed Lewy pathology. Mounting evidence suggests that neuron-released αSYN aggregates could be central to microglial activation, which in turn mounts and orchestrates neuroinflammatory processes potentially harmful to neurons. Therefore, understanding the mechanisms that drive microglial cell activation, polarization and function in PD might have important therapeutic implications. Here, using primary microglia, we investigated the inflammatory potential of pure αSYN fibrils derived from PD patients. We further explored and characterized microglial cell responses to a chronic-type inflammatory stimulation combining PD patient-derived αSYN fibrils (FPD), Tumor necrosis factor-α (TNFα) and prostaglandin E2 (PGE2) (TPFPD). We showed that FPD hold stronger inflammatory potency than pure αSYN fibrils generated de novo. When combined with TNFα and PGE2, FPD polarizes microglia toward a particular functional phenotype departing from FPD-treated cells and featuring lower inflammatory cytokine and higher glutamate release. Whereas metabolomic studies showed that TPFPD-exposed microglia were closely related to classically activated M1 proinflammatory cells, notably with similar tricarboxylic acid cycle disruption, transcriptomic analysis revealed that TPFPD-activated microglia assume a unique molecular signature highlighting upregulation of genes involved in glutathione and iron metabolisms. In particular, TPFPD-specific upregulation of Slc7a11 (which encodes the cystine-glutamate antiporter xCT) was consistent with the increased glutamate response and cytotoxic activity of these cells toward midbrain dopaminergic neurons in vitro. Together, these data further extend the structure-pathological relationship of αSYN fibrillar polymorphs to their innate immune properties and demonstrate that PD-derived αSYN fibrils, TNFα and PGE2 act in concert to drive microglial cell activation toward a specific and highly neurotoxic chronic-type inflammatory phenotype characterized by robust glutamate release and iron retention.
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Affiliation(s)
- Cansu Yildirim-Balatan
- Sorbonne Université, Paris, France
- Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de la Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013, Paris, France
- Inserm UMRS 1127, Paris, France
- CNRS UMR 7225, Paris, France
| | - Alexis Fenyi
- CEA and Laboratory of Neurodegenerative Diseases, CNRS, Institut François Jacob, MIRCen, 92265, Fontenay-aux-Roses, France
| | - Pierre Besnault
- Sorbonne Université, Paris, France
- Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de la Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013, Paris, France
- Inserm UMRS 1127, Paris, France
- CNRS UMR 7225, Paris, France
| | - Lina Gomez
- Sorbonne Université, Paris, France
- Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de la Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013, Paris, France
- Inserm UMRS 1127, Paris, France
- CNRS UMR 7225, Paris, France
| | - Julia E Sepulveda-Diaz
- Sorbonne Université, Paris, France
- Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de la Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013, Paris, France
- Inserm UMRS 1127, Paris, France
- CNRS UMR 7225, Paris, France
| | - Patrick P Michel
- Sorbonne Université, Paris, France
- Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de la Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013, Paris, France
- Inserm UMRS 1127, Paris, France
- CNRS UMR 7225, Paris, France
| | - Ronald Melki
- CEA and Laboratory of Neurodegenerative Diseases, CNRS, Institut François Jacob, MIRCen, 92265, Fontenay-aux-Roses, France
| | - Stéphane Hunot
- Sorbonne Université, Paris, France.
- Institut du Cerveau - Paris Brain Institute - ICM, Hôpital de la Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013, Paris, France.
- Inserm UMRS 1127, Paris, France.
- CNRS UMR 7225, Paris, France.
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3
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Hang TD, Hung HM, Beckers P, Desmet N, Lamrani M, Massie A, Hermans E, Vanommeslaeghe K. Structural investigation of human cystine/glutamate antiporter system xc− (Sxc−) using homology modeling and molecular dynamics. Front Mol Biosci 2022; 9:1064199. [DOI: 10.3389/fmolb.2022.1064199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/15/2022] [Indexed: 12/04/2022] Open
Abstract
The cystine/glutamate antiporter system xc− (Sxc−) belongs to the SLC7 family of plasma membrane transporters. It exports intracellular glutamate along the latter’s concentration gradient as a driving force for cellular uptake of cystine. Once imported, cystine is mainly used for the production of glutathione, a tripeptide thiol crucial in maintenance of redox homeostasis and protection of cells against oxidative stress. Overexpression of Sxc− has been found in several cancer cells, where it is thought to counteract the increased oxidative stress. In addition, Sxc− is important in the central nervous system, playing a complex role in regulating glutamatergic neurotransmission and glutamate toxicity. Accordingly, this transporter is considered a potential target for the treatment of cancer as well as neurodegenerative diseases. Till now, no specific inhibitors are available. We herein present four conformations of Sxc− along its transport pathway, obtained using multi-template homology modeling and refined by means of Molecular Dynamics. Comparison with a very recently released cryo-EM structure revealed an excellent agreement with our inward-open conformation. Intriguingly, our models contain a structured N-terminal domain that is unresolved in the experimental structures and is thought to play a gating role in the transport mechanism of other SLC7 family members. In contrast to the inward-open model, there is no direct experimental counterpart for the other three conformations we obtained, although they are in fair agreement with the other stages of the transport mechanism seen in other SLC7 transporters. Therefore, our models open the prospect for targeting alternative Sxc− conformations in structure-based drug design efforts.
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Maschalidi S, Mehrotra P, Keçeli BN, De Cleene HKL, Lecomte K, Van der Cruyssen R, Janssen P, Pinney J, van Loo G, Elewaut D, Massie A, Hoste E, Ravichandran KS. Targeting SLC7A11 improves efferocytosis by dendritic cells and wound healing in diabetes. Nature 2022; 606:776-784. [PMID: 35614212 DOI: 10.1038/s41586-022-04754-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 04/11/2022] [Indexed: 02/07/2023]
Abstract
Chronic non-healing wounds are a major complication of diabetes, which affects 1 in 10 people worldwide. Dying cells in the wound perpetuate the inflammation and contribute to dysregulated tissue repair1-3. Here we reveal that the membrane transporter SLC7A11 acts as a molecular brake on efferocytosis, the process by which dying cells are removed, and that inhibiting SLC7A11 function can accelerate wound healing. Transcriptomics of efferocytic dendritic cells in mouse identified upregulation of several SLC7 gene family members. In further analyses, pharmacological inhibition of SLC7A11, or deletion or knockdown of Slc7a11 using small interfering RNA enhanced efferocytosis in dendritic cells. Slc7a11 was highly expressed in dendritic cells in skin, and single-cell RNA sequencing of inflamed skin showed that Slc7a11 was upregulated in innate immune cells. In a mouse model of excisional skin wounding, inhibition or loss of SLC7A11 expression accelerated healing dynamics and reduced the apoptotic cell load in the wound. Mechanistic studies revealed a link between SLC7A11, glucose homeostasis and diabetes. SLC7A11-deficient dendritic cells were dependent on aerobic glycolysis using glucose derived from glycogen stores for increased efferocytosis; also, transcriptomics of efferocytic SLC7A11-deficient dendritic cells identified increased expression of genes linked to gluconeogenesis and diabetes. Further, Slc7a11 expression was higher in the wounds of diabetes-prone db/db mice, and targeting SLC7A11 accelerated their wound healing. The faster healing was also linked to the release of the TGFβ family member GDF15 from efferocytic dendritic cells. In sum, SLC7A11 is a negative regulator of efferocytosis, and removing this brake improves wound healing, with important implications for wound management in diabetes.
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Affiliation(s)
- Sophia Maschalidi
- Unit for Cell Clearance in Health and Disease, VIB Center for Inflammation Research, Ghent, Belgium. .,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
| | - Parul Mehrotra
- Unit for Cell Clearance in Health and Disease, VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Burcu N Keçeli
- Unit for Cell Clearance in Health and Disease, VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Hannah K L De Cleene
- Unit for Cell Clearance in Health and Disease, VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Kim Lecomte
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Unit for Cellular and Molecular Pathophysiology, VIB Center for Inflammation Research, Ghent, Belgium
| | - Renée Van der Cruyssen
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Laboratory for Molecular Immunology and Inflammation, Department of Rheumatology, Ghent University Hospital, Ghent, Belgium
| | - Pauline Janssen
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Jonathan Pinney
- The Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.,Department of Microbiology, Immunology, and Cancer Biology, and the Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
| | - Geert van Loo
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Unit for Cellular and Molecular Pathophysiology, VIB Center for Inflammation Research, Ghent, Belgium
| | - Dirk Elewaut
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Laboratory for Molecular Immunology and Inflammation, Department of Rheumatology, Ghent University Hospital, Ghent, Belgium
| | - Ann Massie
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Esther Hoste
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Unit for Cellular and Molecular Pathophysiology, VIB Center for Inflammation Research, Ghent, Belgium
| | - Kodi S Ravichandran
- Unit for Cell Clearance in Health and Disease, VIB Center for Inflammation Research, Ghent, Belgium. .,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium. .,The Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA. .,Department of Microbiology, Immunology, and Cancer Biology, and the Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA. .,Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA.
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5
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Beckers P, Lara O, Belo do Nascimento I, Desmet N, Massie A, Hermans E. Validation of a System xc– Functional Assay in Cultured Astrocytes and Nervous Tissue Samples. Front Cell Neurosci 2022; 15:815771. [PMID: 35095428 PMCID: PMC8793334 DOI: 10.3389/fncel.2021.815771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Disruption of the glutamatergic homeostasis is commonly observed in neurological diseases and has been frequently correlated with the altered expression and/or function of astrocytic high-affinity glutamate transporters. There is, however, a growing interest for the role of the cystine-glutamate exchanger system xc– in controlling glutamate transmission. This exchanger is predominantly expressed in glial cells, especially in microglia and astrocytes, and its dysregulation has been documented in diverse neurological conditions. While most studies have focused on measuring the expression of its specific subunit xCT by RT-qPCR or by Western blotting, the activity of this exchanger in tissue samples remains poorly examined. Indeed, the reported use of sulfur- and carbon-radiolabeled cystine in uptake assays shows several drawbacks related to its short radioactive half-life and its relatively high cost. We here report on the elaborate validation of a method using tritiated glutamate as a substrate for the reversed transport mediated by system xc–. The uptake assay was validated in primary cultured astrocytes, in transfected cells as well as in crude synaptosomes obtained from fresh nervous tissue samples. Working in buffers containing defined concentrations of Na+, allowed us to differentiate the glutamate uptake supported by system xc– or by high-affinity glutamate transporters, as confirmed by using selective pharmacological inhibitors. The specificity was further demonstrated in primary astrocyte cultures from transgenic mice lacking xCT or in cell lines where xCT expression was genetically induced or reduced. As such, this assay appears to be a robust and cost-efficient solution to investigate the activity of this exchanger in physiological and pathological conditions. It also provides a reliable tool for the screening and characterization of new system xc– inhibitors which have been frequently cited as valuable drugs for nervous disorders and cancer.
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Affiliation(s)
- Pauline Beckers
- Group of Neuropharmacology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Olaya Lara
- Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ines Belo do Nascimento
- Group of Neuropharmacology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Nathalie Desmet
- Group of Neuropharmacology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Ann Massie
- Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Emmanuel Hermans
- Group of Neuropharmacology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- *Correspondence: Emmanuel Hermans,
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6
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Bentea E, De Pauw L, Verbruggen L, Winfrey LC, Deneyer L, Moore C, Albertini G, Sato H, Van Eeckhaut A, Meshul CK, Massie A. Aged xCT-Deficient Mice Are Less Susceptible for Lactacystin-, but Not 1-Methyl-4-Phenyl-1,2,3,6- Tetrahydropyridine-, Induced Degeneration of the Nigrostriatal Pathway. Front Cell Neurosci 2022; 15:796635. [PMID: 34975413 PMCID: PMC8718610 DOI: 10.3389/fncel.2021.796635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 11/24/2021] [Indexed: 12/23/2022] Open
Abstract
The astrocytic cystine/glutamate antiporter system x c - (with xCT as the specific subunit) imports cystine in exchange for glutamate and has been shown to interact with multiple pathways in the brain that are dysregulated in age-related neurological disorders, including glutamate homeostasis, redox balance, and neuroinflammation. In the current study, we investigated the effect of genetic xCT deletion on lactacystin (LAC)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced degeneration of the nigrostriatal pathway, as models for Parkinson's disease (PD). Dopaminergic neurons of adult xCT knock-out mice (xCT-/-) demonstrated an equal susceptibility to intranigral injection of the proteasome inhibitor LAC, as their wild-type (xCT+/+) littermates. Contrary to adult mice, aged xCT-/- mice showed a significant decrease in LAC-induced degeneration of nigral dopaminergic neurons, depletion of striatal dopamine (DA) and neuroinflammatory reaction, compared to age-matched xCT+/+ littermates. Given this age-related protection, we further investigated the sensitivity of aged xCT-/- mice to chronic and progressive MPTP treatment. However, in accordance with our previous observations in adult mice (Bentea et al., 2015a), xCT deletion did not confer protection against MPTP-induced nigrostriatal degeneration in aged mice. We observed an increased loss of nigral dopaminergic neurons, but equal striatal DA denervation, in MPTP-treated aged xCT-/- mice when compared to age-matched xCT+/+ littermates. To conclude, we reveal age-related protection against proteasome inhibition-induced nigrostriatal degeneration in xCT-/- mice, while xCT deletion failed to protect nigral dopaminergic neurons of aged mice against MPTP-induced toxicity. Our findings thereby provide new insights into the role of system x c - in mechanisms of dopaminergic cell loss and its interaction with aging.
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Affiliation(s)
- Eduard Bentea
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Laura De Pauw
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lise Verbruggen
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lila C Winfrey
- Neurocytology Laboratory, Veterans Affairs Medical Center, Research Services, Portland, OR, United States
| | - Lauren Deneyer
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Cynthia Moore
- Neurocytology Laboratory, Veterans Affairs Medical Center, Research Services, Portland, OR, United States
| | - Giulia Albertini
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hideyo Sato
- Department of Medical Technology, Niigata University, Niigata, Japan
| | - Ann Van Eeckhaut
- Research Group Experimental Pharmacology, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Vrije Universiteit Brussel, Brussels, Belgium
| | - Charles K Meshul
- Neurocytology Laboratory, Veterans Affairs Medical Center, Research Services, Portland, OR, United States.,Department of Behavioral Neuroscience and Pathology, Oregon Health and Science University, Portland, OR, United States
| | - Ann Massie
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
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7
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Cystine/Glutamate Antiporter in Schizophrenia: From Molecular Mechanism to Novel Biomarker and Treatment. Int J Mol Sci 2021; 22:ijms22189718. [PMID: 34575878 PMCID: PMC8466274 DOI: 10.3390/ijms22189718] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/06/2021] [Accepted: 09/06/2021] [Indexed: 01/04/2023] Open
Abstract
Glutamate, a crucial excitatory neurotransmitter, plays a major role in the modulation of schizophrenia’s pathogenesis. New drug developments for schizophrenia have been prompted by the hypoglutamatergic hypothesis of schizophrenia. The cystine/glutamate antiporter system xc− is related to glutamate-release regulation. Patients with schizophrenia were recently discovered to exhibit downregulation of xc− subunits—the solute carrier (SLC) family 3 member 2 and the SLC family 7 member 11. We searched for relevant studies from 1980, when Bannai and Kitamura first identified the protein subunit system xc− in lung fibroblasts, with the aim of compiling the biological, functional, and pharmacological characteristics of antiporter xc−, which consists of several subunits. Some of them can significantly stimulate the human brain through the glutamate pathway. Initially, extracellular cysteine activates neuronal xc−, causing glutamate efflux. Next, excitatory amino acid transporters enhance the unidirectional transportation of glutamate and sodium. These two biochemical pathways are also crucial to the production of glutathione, a protective agent for neural and glial cells and astrocytes. Investigation of the expression of system xc− genes in the peripheral white blood cells of patients with schizophrenia can facilitate better understanding of the mental disorder and future development of novel biomarkers and treatments for schizophrenia. In addition, the findings further support the hypoglutamatergic hypothesis of schizophrenia.
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8
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Bentea E, Villers A, Moore C, Funk AJ, O’Donovan SM, Verbruggen L, Lara O, Janssen P, De Pauw L, Declerck NB, DePasquale EAK, Churchill MJ, Sato H, Hermans E, Arckens L, Meshul CK, Ris L, McCullumsmith RE, Massie A. Corticostriatal dysfunction and social interaction deficits in mice lacking the cystine/glutamate antiporter. Mol Psychiatry 2021; 26:4754-4769. [PMID: 32366950 PMCID: PMC7609546 DOI: 10.1038/s41380-020-0751-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/07/2020] [Accepted: 04/21/2020] [Indexed: 12/11/2022]
Abstract
The astrocytic cystine/glutamate antiporter system xc- represents an important source of extracellular glutamate in the central nervous system, with potential impact on excitatory neurotransmission. Yet, its function and importance in brain physiology remain incompletely understood. Employing slice electrophysiology and mice with a genetic deletion of the specific subunit of system xc-, xCT (xCT-/- mice), we uncovered decreased neurotransmission at corticostriatal synapses. This effect was partly mitigated by replenishing extracellular glutamate levels, indicating a defect linked with decreased extracellular glutamate availability. We observed no changes in the morphology of striatal medium spiny neurons, the density of dendritic spines, or the density or ultrastructure of corticostriatal synapses, indicating that the observed functional defects are not due to morphological or structural abnormalities. By combining electron microscopy with glutamate immunogold labeling, we identified decreased intracellular glutamate density in presynaptic terminals, presynaptic mitochondria, and in dendritic spines of xCT-/- mice. A proteomic and kinomic screen of the striatum of xCT-/- mice revealed decreased expression of presynaptic proteins and abnormal kinase network signaling, that may contribute to the observed changes in postsynaptic responses. Finally, these corticostriatal deregulations resulted in a behavioral phenotype suggestive of autism spectrum disorder in the xCT-/- mice; in tests sensitive to corticostriatal functioning we recorded increased repetitive digging behavior and decreased sociability. To conclude, our findings show that system xc- plays a previously unrecognized role in regulating corticostriatal neurotransmission and influences social preference and repetitive behavior.
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Affiliation(s)
- Eduard Bentea
- grid.8767.e0000 0001 2290 8069Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Agnès Villers
- grid.8364.90000 0001 2184 581XDepartment of Neurosciences, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Cynthia Moore
- grid.410404.50000 0001 0165 2383Research Services, Neurocytology Laboratory, Veterans Affairs Medical Center, Portland, OR USA
| | - Adam J. Funk
- grid.267337.40000 0001 2184 944XDepartment of Neurosciences, University of Toledo College of Medicine, Toledo, OH USA
| | - Sinead M. O’Donovan
- grid.267337.40000 0001 2184 944XDepartment of Neurosciences, University of Toledo College of Medicine, Toledo, OH USA
| | - Lise Verbruggen
- grid.8767.e0000 0001 2290 8069Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Olaya Lara
- grid.8767.e0000 0001 2290 8069Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Pauline Janssen
- grid.8767.e0000 0001 2290 8069Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Laura De Pauw
- grid.8767.e0000 0001 2290 8069Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Noemi B. Declerck
- grid.8767.e0000 0001 2290 8069Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Erica A. K. DePasquale
- grid.239573.90000 0000 9025 8099Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USA ,grid.24827.3b0000 0001 2179 9593Department of Biomedical Informatics, University of Cincinnati, Cincinnati, OH USA
| | - Madeline J. Churchill
- grid.410404.50000 0001 0165 2383Research Services, Neurocytology Laboratory, Veterans Affairs Medical Center, Portland, OR USA
| | - Hideyo Sato
- grid.260975.f0000 0001 0671 5144Department of Medical Technology, Faculty of Medicine, Laboratory of Biochemistry and Molecular Biology, Niigata University, Niigata, Japan
| | - Emmanuel Hermans
- grid.7942.80000 0001 2294 713XInstitute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Lutgarde Arckens
- grid.5596.f0000 0001 0668 7884Laboratory of Neuroplasticity and Neuroproteomics, and Leuven Brain Institute (LBI), KU Leuven—University of Leuven, Leuven, Belgium
| | - Charles K. Meshul
- grid.410404.50000 0001 0165 2383Research Services, Neurocytology Laboratory, Veterans Affairs Medical Center, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR USA
| | - Laurence Ris
- grid.8364.90000 0001 2184 581XDepartment of Neurosciences, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Robert E. McCullumsmith
- grid.267337.40000 0001 2184 944XDepartment of Neurosciences, University of Toledo College of Medicine, Toledo, OH USA
| | - Ann Massie
- Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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9
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Miyazaki I, Asanuma M. Neuron-Astrocyte Interactions in Parkinson's Disease. Cells 2020; 9:cells9122623. [PMID: 33297340 PMCID: PMC7762285 DOI: 10.3390/cells9122623] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/20/2020] [Accepted: 12/05/2020] [Indexed: 12/12/2022] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disease. PD patients exhibit motor symptoms such as akinesia/bradykinesia, tremor, rigidity, and postural instability due to a loss of nigrostriatal dopaminergic neurons. Although the pathogenesis in sporadic PD remains unknown, there is a consensus on the involvement of non-neuronal cells in the progression of PD pathology. Astrocytes are the most numerous glial cells in the central nervous system. Normally, astrocytes protect neurons by releasing neurotrophic factors, producing antioxidants, and disposing of neuronal waste products. However, in pathological situations, astrocytes are known to produce inflammatory cytokines. In addition, various studies have reported that astrocyte dysfunction also leads to neurodegeneration in PD. In this article, we summarize the interaction of astrocytes and dopaminergic neurons, review the pathogenic role of astrocytes in PD, and discuss therapeutic strategies for the prevention of dopaminergic neurodegeneration. This review highlights neuron-astrocyte interaction as a target for the development of disease-modifying drugs for PD in the future.
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Iovino L, Tremblay ME, Civiero L. Glutamate-induced excitotoxicity in Parkinson's disease: The role of glial cells. J Pharmacol Sci 2020; 144:151-164. [PMID: 32807662 DOI: 10.1016/j.jphs.2020.07.011] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/30/2020] [Accepted: 07/27/2020] [Indexed: 12/11/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the central nervous system. Glutamate transmission efficiency depends on the correct functionality and expression of a plethora of receptors and transporters, located both on neurons and glial cells. Of note, glutamate reuptake by dedicated transporters prevents its accumulation at the synapse as well as non-physiological spillover. Indeed, extracellular glutamate increase causes aberrant synaptic signaling leading to neuronal excitotoxicity and death. Moreover, extrasynaptic glutamate diffusion is strongly associated with glia reaction and neuroinflammation. Glutamate-induced excitotoxicity is mainly linked to an impaired ability of glial cells to reuptake and respond to glutamate, then this is considered a common hallmark in many neurodegenerative diseases, including Parkinson's disease (PD). In this review, we discuss the function of astrocytes and microglia in glutamate homeostasis, focusing on how glial dysfunction causes glutamate-induced excitotoxicity leading to neurodegeneration in PD.
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Affiliation(s)
- L Iovino
- Department of Biology, University of Padova, Italy
| | - M E Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, Canada
| | - L Civiero
- Department of Biology, University of Padova, Italy; IRCCS San Camillo Hospital, Venice, Italy.
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11
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Sharma M, Anirudh CR. In silico characterization of residues essential for substrate binding of human cystine transporter, xCT. J Mol Model 2019; 25:336. [PMID: 31705320 DOI: 10.1007/s00894-019-4233-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 10/14/2019] [Indexed: 02/06/2023]
Abstract
xCT is a sodium-independent amino acid antiporter that imports L-cystine and exports L-glutamate in a 1:1 ratio. It is a component of heterodimeric amino acid transporter system Xc- working at the cross-roads of maintaining neurological processes and regulating antioxidant defense. The transporter has 12 transmembrane domains with intracellular N- and C-termini, and like other transporter proteins can undergo various conformational changes while switching the ligand accessibilities from intracellular to extracellular site. In the present study, we generated two homology models of human xCT in two distinct conformations: inward-facing occluded state and outward-facing open state. Our results indicated the substrate translocation channel composed of transmembrane helices TMs 1, 3, 6, 8, and 10. We docked anionic L-cystine and L-glutamate within the cavities to assess the two distinct binding scenarios for xCT as antiporter. We also assessed the interactions between the ligands and transporter and observed that ligands bind to similar residues within the channel. Using MM-PBSA/MM-GBSA approach, we computed the binding energies of these ligands to different conformational states. Cystine and glutamate bind xCT with favorable binding energies, with more favorable binding observed in inward occluded state than in outward open state. We further computed the residue-wise decomposition of these binding energies and identified the residues as essential for substrate binding/permeation. Filtering the residues that form favorable energetic contributions to the ligand binding in both the states, our studies suggest T56, A60, R135, A138, V141, Y244, A247, F250, S330, L392, and R396 as critical residues for ligand binding as well as ligand transport for any conformational state adopted by xCT during its transport cycle. .Graphical Abstract.
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Affiliation(s)
- Monika Sharma
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Sector 81, Knowledge City, SAS, Nagar, Punjab, India.
| | - C R Anirudh
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Sector 81, Knowledge City, SAS, Nagar, Punjab, India
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12
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Demuyser T, Deneyer L, Bentea E, Albertini G, Femenia T, Walrave L, Sato H, Danbolt NC, De Bundel D, Michotte A, Lindskog M, Massie A, Smolders I. Slc7a11 (xCT) protein expression is not altered in the depressed brain and system xc- deficiency does not affect depression-associated behaviour in the corticosterone mouse model. World J Biol Psychiatry 2019; 20:381-392. [PMID: 28882088 DOI: 10.1080/15622975.2017.1371332] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Objectives: The cystine/glutamate antiporter (system xc-) is believed to contribute to nonvesicular glutamate release from glial cells in various brain areas. Although recent investigations implicate system xc- in mood disorders, unambiguous evidence has not yet been established. Therefore, we evaluated the possible role of system xc- in the depressive state. Methods: We conducted a protein expression analysis of the specific subunit of system xc- (xCT) in brain regions of the corticosterone mouse model, Flinders Sensitive Line rat model and post-mortem tissue of depressed patients. We next subjected system xc- deficient mice to the corticosterone model and analysed their behaviour in several tests. Lastly, we subjected additional cohorts of xCT-deficient and wild-type mice to N-acetylcysteine treatment to unveil whether the previously reported antidepressant-like effects are dependent upon system xc-. Results: We did not detect any changes in xCT expression levels in the animal models or patients compared to proper controls. Furthermore, loss of system xc- had no effect on depression- and anxiety-like behaviour. Finally, the antidepressant-like effects of N-acetylcysteine are not mediated via system xc-. Conclusions: xCT protein expression is not altered in the depressed brain and system xc- deficiency does not affect depression-associated behaviour in the corticosterone mouse model.
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Affiliation(s)
- Thomas Demuyser
- a Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information , Center for Neurosciences (C4N), Vrije Universiteit Brussel , Brussels , Belgium
| | - Lauren Deneyer
- b Department of Pharmaceutical Biotechnology and Molecular Biology , C4N, Vrije Universiteit Brussel , Brussels , Belgium
| | - Eduard Bentea
- b Department of Pharmaceutical Biotechnology and Molecular Biology , C4N, Vrije Universiteit Brussel , Brussels , Belgium
| | - Giulia Albertini
- a Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information , Center for Neurosciences (C4N), Vrije Universiteit Brussel , Brussels , Belgium
| | - Teresa Femenia
- c Department of Neuroscience , Karolinska Institutet , Stockholm , Sweden
| | - Laura Walrave
- a Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information , Center for Neurosciences (C4N), Vrije Universiteit Brussel , Brussels , Belgium
| | - Hideyo Sato
- d Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology , Niigata University , Niigata , Japan
| | - Niels C Danbolt
- e Department of Molecular Medicine , Institute of Basic Medical Sciences, University of Oslo , Oslo , Norway
| | - Dimitri De Bundel
- a Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information , Center for Neurosciences (C4N), Vrije Universiteit Brussel , Brussels , Belgium
| | - Alex Michotte
- f Experimental Pathology and Neuropathology , University Hospital Brussels, Vrije Universiteit Brussel , Brussels , Belgium
| | - Maria Lindskog
- c Department of Neuroscience , Karolinska Institutet , Stockholm , Sweden
| | - Ann Massie
- b Department of Pharmaceutical Biotechnology and Molecular Biology , C4N, Vrije Universiteit Brussel , Brussels , Belgium
| | - Ilse Smolders
- a Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information , Center for Neurosciences (C4N), Vrije Universiteit Brussel , Brussels , Belgium
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13
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Loewen JL, Albertini G, Dahle EJ, Sato H, Smolders IJ, Massie A, Wilcox KS. Genetic and pharmacological manipulation of glial glutamate transporters does not alter infection-induced seizure activity. Exp Neurol 2019; 318:50-60. [PMID: 31022385 DOI: 10.1016/j.expneurol.2019.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/19/2019] [Accepted: 04/20/2019] [Indexed: 12/11/2022]
Abstract
The contribution of glial transporters to glutamate movement across the membrane has been identified as a potential target for anti-seizure therapies. Two such glutamate transporters, GLT-1 and system xc-, are expressed on glial cells, and modulation of their expression and function have been identified as a means by which seizures, neuronal injury, and gliosis can be reduced in models of brain injury. While GLT-1 is responsible for the majority of glutamate uptake in the brain, system xc- releases glutamate in the extracellular cleft in exchange for cystine and represents as such the major source of hippocampal extracellular glutamate. Using the Theiler's Murine Encephalomyelitis Virus (TMEV) model of viral-induced epilepsy, we have taken two well-studied approaches, one pharmacological, one genetic, to investigate the potential role(s) of GLT-1 and system xc- in TMEV-induced pathology. Our findings suggest that the methods we utilized to modulate these glial transporters, while effective in other models, are not sufficient to reduce the number or severity of behavioral seizures in TMEV-infected mice. However, genetic knockout of xCT, the specific subunit of system xc-, may have cellular effects, as we observed a slight decrease in neuronal injury caused by TMEV and an increase in astrogliosis in the CA1 region of the hippocampus. Furthermore, xCT knockout caused an increase in GLT-1 expression selectively in the cortex. These findings have significant implications for both the characterization of the TMEV model as well as for future efforts to discover novel and effective anti-seizure drugs.
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Affiliation(s)
- Jaycie L Loewen
- Department of Pharmacology and Toxicology, University of Utah, USA; Interdepartmental Program in Neuroscience, University of Utah, USA
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium
| | - E Jill Dahle
- Department of Pharmacology and Toxicology, University of Utah, USA
| | - Hideyo Sato
- Department of Medical Technology, Niigata University, Japan
| | - Ilse J Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, C4N, Vrije Universiteit Brussel, Belgium
| | - Karen S Wilcox
- Department of Pharmacology and Toxicology, University of Utah, USA; Interdepartmental Program in Neuroscience, University of Utah, USA.
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14
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Čolović M, Yang H, Merkens H, Colpo N, Bénard F, Schaffer P. Non-invasive Use of Positron Emission Tomography to Monitor Diethyl maleate and Radiation-Induced Changes in System x C- Activity in Breast Cancer. Mol Imaging Biol 2019; 21:1107-1116. [PMID: 30838549 DOI: 10.1007/s11307-019-01331-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE The system xC- transporter is upregulated in cancer cells in response to oxidative stress (OS). 5-[18F]fluoroaminosuberic acid ([18F]FASu) has been reported as a novel positron emission tomography (PET) imaging agent, targeting system xC-. The goal of this study was to evaluate the utility of [18F]FASu in monitoring cellular response to diethyl maleate (DEM) and radiation-induced OS fluctuations. PROCEDURES [18F]FASu uptake by breast cancer cells was studied in correlation to OS biomarkers: glutathione (GSH) and reactive oxygen species (ROS), as well as transcriptional and translational levels of xCT (the functional subunit of xC-). System xC- inhibitor, sulfasalazine (SSZ), and small interfering RNA (siRNA) knockdown were used as negative controls. Radiotracer uptake was evaluated in three breast cancer models: MDA-MB-231, MCF-7, and ZR-75-1, at two-time points (1 h and 16 h) following OS induction. In vivo [18F]FASu imaging and biodistribution were performed using MDA-MB-231 xenograft-bearing mice at 16 and 24 h post-radiation treatment. RESULTS [18F]FASu uptake was positively correlated to intracellular GSH and SLC7A11 expression levels, and radiotracer uptake was induced both by radiation treatment and by DEM at time points longer than 3 h. In an in vivo setting, there was no statistically significant uptake difference between irradiated and control tumors. CONCLUSION [18F]FASu is a specific system xC- PET radiotracer and as such it can be used to monitor system xC- activity due to OS. As such, [18F]FASu has the potential to be used in therapy response monitoring by PET. Further optimization is required for in vivo application.
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Affiliation(s)
- Milena Čolović
- Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada.,British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - Hua Yang
- Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - Helen Merkens
- British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - Nadine Colpo
- British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - François Bénard
- British Columbia Cancer Research Centre, Vancouver, BC, Canada. .,Molecular Oncology, British Columbia Cancer Research Centre, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada. .,Department of Radiology, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
| | - Paul Schaffer
- Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada. .,Department of Radiology, Faculty of Medicine, University of British Columbia, Vancouver, Canada. .,Department of Chemistry, Faculty of Science, Simon Fraser University, Vancouver, Canada.
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15
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Albertini G, Deneyer L, Ottestad-Hansen S, Zhou Y, Ates G, Walrave L, Demuyser T, Bentea E, Sato H, De Bundel D, Danbolt NC, Massie A, Smolders I. Genetic deletion of xCT attenuates peripheral and central inflammation and mitigates LPS-induced sickness and depressive-like behavior in mice. Glia 2018; 66:1845-1861. [PMID: 29693305 DOI: 10.1002/glia.23343] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/18/2022]
Abstract
The communication between the immune and central nervous system (CNS) is affected in many neurological disorders. Peripheral injections of the endotoxin lipopolysaccharide (LPS) are widely used to study this communication: an LPS challenge leads to a biphasic syndrome that starts with acute sickness and is followed by persistent brain inflammation and chronic behavioral alterations such as depressive-like symptoms. In vitro, the response to LPS treatment has been shown to involve enhanced expression of system <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>x</mml:mi></mml:mrow> <mml:mrow><mml:mi>c</mml:mi></mml:mrow> <mml:mrow><mml:mo>-</mml:mo></mml:mrow> </mml:msubsup> </mml:math> . This cystine-glutamate antiporter, with xCT as specific subunit, represents the main glial provider of extracellular glutamate in mouse hippocampus. Here we injected male xCT knockout and wildtype mice with a single intraperitoneal dose of 5 mg/kg LPS. LPS-injection increased hippocampal xCT expression but did not alter the mainly astroglial localization of the xCT protein. Peripheral and central inflammation (as defined by cytokine levels and morphological activation of microglia) as well as LPS-induced sickness and depressive-like behavior were significantly attenuated in xCT-deficient mice compared with wildtype mice. Our study is the first to demonstrate the involvement of system <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>x</mml:mi></mml:mrow> <mml:mrow><mml:mi>c</mml:mi></mml:mrow> <mml:mrow><mml:mo>-</mml:mo></mml:mrow> </mml:msubsup> </mml:math> in peripheral and central inflammation in vivo and the potential therapeutic relevance of its inhibition in brain disorders characterized by peripheral and central inflammation, such as depression.
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Affiliation(s)
- Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Lauren Deneyer
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Sigrid Ottestad-Hansen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0372, Norway
| | - Yun Zhou
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0372, Norway
| | - Gamze Ates
- Department of In Vitro Toxicology and Dermato-cosmetology, Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Laura Walrave
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Hideyo Sato
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology, Niigata University, Niigata, 951-8518, Japan
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Niels C Danbolt
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0372, Norway
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, 1090, Belgium
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16
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Albano R, Lobner D. Transport of BMAA into Neurons and Astrocytes by System x c. Neurotox Res 2017; 33:1-5. [PMID: 28470569 DOI: 10.1007/s12640-017-9739-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/30/2017] [Accepted: 04/21/2017] [Indexed: 01/13/2023]
Abstract
The study of the mechanism of β-N-methylamino-L-alanine (BMAA) neurotoxicity originally focused on its effects at the N-methyl-D-aspartate (NMDA) receptor. In recent years, it has become clear that its mechanism of action is more complicated. First, there are certain cell types, such as motor neurons and cholinergic neurons, where the dominate mechanism of toxicity is through action at AMPA receptors. Second, even in cortical neurons where the primary mechanism of toxicity appears to be activation of NMDA receptors, there are other mechanisms involved. We found that along with NMDA receptors, activation of mGLuR5 receptors and effects on the cystine/glutamate antiporter (system xc-) were involved in the toxicity. The effects on system xc- are of particular interest. System xc- mediates the transport of cystine into the cell in exchange for releasing glutamate into the extracellular fluid. By releasing glutamate, system xc- can potentially cause excitotoxicity. However, through providing cystine to the cell, it regulates the levels of cellular glutathione (GSH), the main endogenous intracellular antioxidant, and in this way may protect cells against oxidative stress. We have previously published that BMAA inhibits cystine uptake leading to GSH depletion and had indirect evidence that BMAA is transported into the cells by system xc-. We now present direct evidence that BMAA is transported into both astrocytes and neurons through system xc-. The fact that BMAA is transported by system xc- also provides a mechanism for BMAA to enter brain cells potentially leading to misincorporation into proteins and protein misfolding.
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Affiliation(s)
- Rebecca Albano
- Department of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426, Milwaukee, WI, 53233, USA
| | - Doug Lobner
- Department of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426, Milwaukee, WI, 53233, USA.
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17
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Figuera-Losada M, Thomas AG, Stathis M, Stockwell BR, Rojas C, Slusher BS. Development of a primary microglia screening assay and its use to characterize inhibition of system x c- by erastin and its analogs. Biochem Biophys Rep 2017; 9:266-272. [PMID: 28956014 PMCID: PMC5614578 DOI: 10.1016/j.bbrep.2016.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/21/2016] [Accepted: 12/29/2016] [Indexed: 01/03/2023] Open
Abstract
The inflammatory response in the central nervous system involves activated microglia. Under normal conditions they remove damaged neurons by phagocytosis. On the other hand, neurodegenerative diseases are thought to involve chronic microglia activation resulting in release of excess glutamate, proinflammatory cytokines and reactive oxygen species, leading to neuronal death. System xC- cystine/glutamate antiporter (SXC), a sodium independent heterodimeric transporter found in microglia and astrocytes in the CNS, imports cystine into the cell and exports glutamate. SXC has been shown to be upregulated in neurodegenerative diseases including multiple sclerosis, ALS, neuroAIDS Parkinson's disease and Alzheimer's disease. Consequently, SXC inhibitors could be of use in the treatment of diseases characterized by neuroinflammation and glutamate excitotoxicity. We report on the optimization of a primary microglia-based assay to screen for SXC inhibitors. Rat primary microglia were activated using lipopolysaccharides (LPS) and glutamate release and cystine uptake were monitored by fluorescence and radioactivity respectively. LPS-induced glutamate release increased with increasing cell density, time of incubation and LPS concentration. Conditions to screen for SXC inhibitors were optimized in 96-well format and subsequently used to evaluate SXC inhibitors. Known SXC inhibitors sulfasalazine, S-4CPG and erastin blocked glutamate release and cystine uptake while R-4CPG, the inactive enantiomer of S-4CPG, failed to inhibit glutamate release or cystine transport. In addition, several erastin analogs were evaluated using primary microglia and found to have EC50 values in agreement with previous studies using established cell lines. Conditions to screen for SXC inhibitors were optimized in 96-well format. Assay enables higher throughput screens for SXC inhibitors with primary microglia. Screening assay was used to evaluate prototype SXC inhibitors and erastin analogs.
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Affiliation(s)
- Mariana Figuera-Losada
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Ajit G. Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Marigo Stathis
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Brent R. Stockwell
- Departments of Biological Sciences and Chemistry, Columbia University, New York, NY 10027, United States
| | - Camilo Rojas
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Barbara S. Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Departments of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
- Correspondence to: Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, United States.
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18
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Merckx E, Albertini G, Paterka M, Jensen C, Albrecht P, Dietrich M, Van Liefferinge J, Bentea E, Verbruggen L, Demuyser T, Deneyer L, Lewerenz J, van Loo G, De Keyser J, Sato H, Maher P, Methner A, Massie A. Absence of system x c- on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis. J Neuroinflammation 2017; 14:9. [PMID: 28086920 PMCID: PMC5237180 DOI: 10.1186/s12974-016-0787-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 12/28/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System xc- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration. METHODS Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system xc-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT-/-) mice and irradiated mice reconstituted in xCT-/- bone marrow (BM), to their proper wild type (xCT+/+) controls. RESULTS xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT+/+ mice, xCT-/- mice were equally susceptible to EAE, whereas mice transplanted with xCT-/- BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected. CONCLUSIONS Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system xc- on immune cells invading the CNS participates to EAE. Since a total loss of system xc- had no net beneficial effects, these results have important implications for targeting system xc- for treatment of MS.
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Affiliation(s)
- Ellen Merckx
- Center for Neurosciences (C4N), Department of Pharmaceutical Biotechnology and Molecular Biology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Giulia Albertini
- Center for Neurosciences (C4N), Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels, Belgium
| | - Magdalena Paterka
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Cathy Jensen
- Center for Neurosciences (C4N), Department of Pharmaceutical Biotechnology and Molecular Biology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Philipp Albrecht
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| | - Michael Dietrich
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| | - Joeri Van Liefferinge
- Center for Neurosciences (C4N), Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels, Belgium
| | - Eduard Bentea
- Center for Neurosciences (C4N), Department of Pharmaceutical Biotechnology and Molecular Biology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Lise Verbruggen
- Center for Neurosciences (C4N), Department of Pharmaceutical Biotechnology and Molecular Biology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Thomas Demuyser
- Center for Neurosciences (C4N), Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lauren Deneyer
- Center for Neurosciences (C4N), Department of Pharmaceutical Biotechnology and Molecular Biology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Jan Lewerenz
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Geert van Loo
- Inflammation Research Center, VIB and Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Jacques De Keyser
- Center for Neurosciences (C4N), Department of Neurology, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Hideyo Sato
- Department of Medical Technology, Faculty of Medicine, Niigata University, Niigata, Japan
| | - Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Axel Methner
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Ann Massie
- Center for Neurosciences (C4N), Department of Pharmaceutical Biotechnology and Molecular Biology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium.
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Bentea E, Van Liefferinge J, Verbruggen L, Martens K, Kobayashi S, Deneyer L, Demuyser T, Albertini G, Maes K, Sato H, Smolders I, Lewerenz J, Massie A. Zonisamide attenuates lactacystin-induced parkinsonism in mice without affecting system x c<sup/>. Exp Neurol 2016; 290:15-28. [PMID: 28024798 DOI: 10.1016/j.expneurol.2016.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 12/15/2016] [Accepted: 12/21/2016] [Indexed: 11/29/2022]
Abstract
Zonisamide (ZNS), an anticonvulsant drug exhibiting symptomatic effects in Parkinson's disease (PD), was recently reported to exert neuroprotection in rodent models. One of the proposed neuroprotective mechanisms involves increased protein expression of xCT, the specific subunit of the cystine/glutamate antiporter system xc-, inducing glutathione (GSH) synthesis. Here, we investigated the outcome of ZNS treatment in a mouse model of PD based on intranigral proteasome inhibition, and whether the observed effects would be mediated by system xc-. The proteasome inhibitor lactacystin (LAC) was administered intranigrally to male C57BL/6J mice receiving repeated intraperitoneal injections of either ZNS 30mgkg-1 or vehicle. Drug administration was initiated three days prior to stereotaxic LAC injection and was maintained until six days post-surgery. One week after lesion, mice were behaviorally assessed and investigated in terms of nigrostriatal neurodegeneration and molecular changes at the level of the basal ganglia, including expression levels of xCT. ZNS reduced the loss of nigral dopaminergic neurons following LAC injection and the degree of sensorimotor impairment. ZNS failed, however, to modulate xCT expression in basal ganglia of lesioned mice. In a separate set of experiments, the impact of ZNS treatment on system xc- was investigated in control conditions in vivo as well as in vitro. Similarly, ZNS did not influence xCT or glutathione levels in naive male C57BL/6J mice, nor did it alter system xc- activity or glutathione content in vitro. Taken together, these results demonstrate that ZNS treatment provides neuroprotection and behavioral improvement in a PD mouse model based on proteasome inhibition via system xc- independent mechanisms.
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Affiliation(s)
- Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Joeri Van Liefferinge
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lise Verbruggen
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Katleen Martens
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Sho Kobayashi
- Department of Food and Applied Life Sciences, Yamagata University, Yamagata, Japan
| | - Lauren Deneyer
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Katrien Maes
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hideyo Sato
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology, Niigata University, Niigata, Japan
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jan Lewerenz
- Department of Neurology, Ulm University, Ulm, Germany
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium.
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Lin CH, Lin PP, Lin CY, Lin CH, Huang CH, Huang YJ, Lane HY. Decreased mRNA expression for the two subunits of system xc(-), SLC3A2 and SLC7A11, in WBC in patients with schizophrenia: Evidence in support of the hypo-glutamatergic hypothesis of schizophrenia. J Psychiatr Res 2016; 72:58-63. [PMID: 26540405 DOI: 10.1016/j.jpsychires.2015.10.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND The cystine/glutamate antiporter system xc(-), playing a critical role in the regulation of glutamate release, might be implicated in the pathogenesis of schizophrenia. This study examined whether peripheral expressions of the system xc(-) subunits are characteristic of schizophrenia. METHODS Expression of system xc(-) genes including SLC3A2 and SLC7A11 in peripheral WBCs of patients with schizophrenia and healthy individuals were measured using quantitative PCR. Both psychotropic-free and medicated patients with schizophrenia were recruited. RESULTS A total of 96 schizophrenia patients (48 medicated and 48 drug-free) and 96 healthy individuals were enrolled. The mRNA expression levels using the 2(-ΔΔC)T Method of both SLC3A2 and SLC7A11 in WBCs of schizophrenia patients were markedly lower than that of healthy individuals (0.22 and 0.48, respectively, the mRNA expression level of normal controls was normalized to 1). There was no significant difference between medicated and drug-free patients in the mRNA expressions of both SLC3A2 and SLC7A11. The Receiver Operating Characteristics (ROC) analysis of SLC3A2 mRNA levels using ΔΔCT values for drug-free schizophrenia patients vs. healthy controls determined an optimal cutoff value, 0.801, with high sensitivity (1.000) and modest specificity (0.694) (area under curve of ROC = 0.794). CONCLUSION This is the first study indicating that the peripheral mRNA expression levels of SLC7A11 and SLC3A2 may be lower in patients with schizophrenia than healthy individuals. The finding supports the hypo-glutamatergic neurotransmission hypothesis in schizophrenia. Whether mRNA expression of system xc(-) subunits genes, particularly SLC3A2, could serve as a potential biomarker of schizophrenia needs further studies.
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Affiliation(s)
- Chieh-Hsin Lin
- Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan; Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Pei-Pei Lin
- Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Chun-Yuan Lin
- Department of General Psychiatry, Tsaotun Psychiatric Center, Taichung, Taiwan
| | - Ching-Hua Lin
- Department of Psychiatry, Kai-Suan Psychiatric Hospital, Kaohsiung, Taiwan
| | - Chiung-Hsien Huang
- Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Jhen Huang
- Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan
| | - Hsien-Yuan Lane
- Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan; Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan.
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Patel D, Kharkar PS, Nandave M. Emerging roles of system antiporter and its inhibition in CNS disorders. Mol Membr Biol 2015; 32:89-116. [PMID: 26508554 DOI: 10.3109/09687688.2015.1096972] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
| | - Prashant S. Kharkar
- Department of Pharmaceutical Chemistry, SPP School of Pharmacy and Technology Management, SVKM’s NMIMS University, Mumbai, India
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Van Liefferinge J, Bentea E, Demuyser T, Albertini G, Follin-Arbelet V, Holmseth S, Merckx E, Sato H, Aerts JL, Smolders I, Arckens L, Danbolt NC, Massie A. Comparative analysis of antibodies to xCT (Slc7a11): Forewarned is forearmed. J Comp Neurol 2015; 524:1015-32. [DOI: 10.1002/cne.23889] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/24/2015] [Accepted: 08/25/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Joeri Van Liefferinge
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Virginie Follin-Arbelet
- Department of Molecular Medicine, Institute of Basic Medical Sciences; University of Oslo; Oslo 0317 Norway
| | - Silvia Holmseth
- Department of Molecular Medicine, Institute of Basic Medical Sciences; University of Oslo; Oslo 0317 Norway
| | - Ellen Merckx
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Hideyo Sato
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology; Niigata University; Niigata Niigata Prefecture 950-2181 Japan
| | - Joeri L. Aerts
- Laboratory of Molecular and Cellular Therapy, Department of Immunology-Physiology; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
| | - Lutgarde Arckens
- Laboratory of Neuroplasticity and Neuroproteomics; KU Leuven; Leuven 3000 Belgium
| | - Niels C. Danbolt
- Department of Molecular Medicine, Institute of Basic Medical Sciences; University of Oslo; Oslo 0317 Norway
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences; Vrije Universiteit Brussel; Brussels 1090 Belgium
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Massie A, Boillée S, Hewett S, Knackstedt L, Lewerenz J. Main path and byways: non-vesicular glutamate release by system xc(-) as an important modifier of glutamatergic neurotransmission. J Neurochem 2015; 135:1062-79. [PMID: 26336934 DOI: 10.1111/jnc.13348] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/24/2015] [Accepted: 08/25/2015] [Indexed: 12/14/2022]
Abstract
System xc(-) is a cystine/glutamate antiporter that exchanges extracellular cystine for intracellular glutamate. Cystine is intracellularly reduced to cysteine, a building block of GSH. As such, system xc(-) can regulate the antioxidant capacity of cells. Moreover, in several brain regions, system xc(-) is the major source of extracellular glutamate. As such this antiporter is able to fulfill key physiological functions in the CNS, while evidence indicates it also plays a role in certain brain pathologies. Since the transcription of xCT, the specific subunit of system xc(-), is enhanced by the presence of reactive oxygen species and inflammatory cytokines, system xc(-) could be involved in toxic extracellular glutamate release in neurological disorders that are associated with increased oxidative stress and neuroinflammation. System xc(-) has also been reported to contribute to the invasiveness of brain tumors and, as a source of extracellular glutamate, could participate in the induction of peritumoral seizures. Two independent reviews (Pharmacol. Rev. 64, 2012, 780; Antioxid. Redox Signal. 18, 2013, 522), approached from a different perspective, have recently been published on the functions of system xc(-) in the CNS. In this review, we highlight novel achievements and insights covering the regulation of system xc(-) as well as its involvement in emotional behavior, cognition, addiction, neurological disorders and glioblastomas, acquired in the past few years. System xc(-) constitutes an important source of extrasynaptic glutamate in the brain. By modulating the tone of extrasynaptic metabotropic or ionotropic glutamate receptors, it affects excitatory neurotransmission, the threshold for overexcitation and excitotoxicity and, as a consequence, behavior. This review describes the current knowledge of how system xc(-) is regulated and involved in physiological as well as pathophysiological brain functioning.
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Affiliation(s)
- Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Séverine Boillée
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Sandra Hewett
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Lori Knackstedt
- Psychology Department, University of Florida, Gainesville, Florida, USA
| | - Jan Lewerenz
- Department of Neurology, Ulm University, Oberer Eselsberg 45, Ulm, Germany
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El Arfani A, Albertini G, Bentea E, Demuyser T, Van Eeckhaut A, Smolders I, Massie A. Alterations in the motor cortical and striatal glutamatergic system and D-serine levels in the bilateral 6-hydroxydopamine rat model for Parkinson's disease. Neurochem Int 2015; 88:88-96. [PMID: 26172319 DOI: 10.1016/j.neuint.2015.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 06/30/2015] [Accepted: 07/07/2015] [Indexed: 01/05/2023]
Abstract
Parkinson's disease (PD) is hallmarked by progressive degeneration of the substantia nigra pars compacta (SNc) neurons and is associated with aberrant glutamatergic activity. However, studies on the glutamatergic system in the motor cortex and striatum, two motor loop-related areas, are lacking in the clinically relevant bilateral SNc 6-hydroxydopamine (6-OHDA) rat model, and therefore led to the rationale behind the present investigations. Using Western blotting, the expression levels of the glial glutamate transporters, GLT-1 and GLAST, as well as xCT, the specific subunit of system xc(-), and the vesicular glutamate transporters, VGLUT1 and 2 were investigated at two different time points (1 week and 2 weeks) post-lesion. In addition, the total content of glutamate was measured. Moreover, the total D-serine levels were, to the best of our knowledge, studied for the first time in these two PD-related areas in the bilateral 6-OHDA rat model. In the motor cortex, no significant changes were observed in the different glutamate transporter expression levels in the bilaterally-lesioned rats. In the striatum, GLAST expression was significantly decreased at both time points whereas VGLUT1 and 2 expressions were significantly decreased 2 weeks after bilateral 6-OHDA lesion. Interestingly, bilateral 6-OHDA SNc lesion resulted in an enhancement of the total d-serine content in both motor cortex and striatum at 1 week post-lesion suggesting its possible involvement in the pathophysiology of PD. In conclusion, this study demonstrates disturbed glutamate and D-serine regulation in the bilateral SNc-lesioned brain which could contribute to the behavioral impairments in PD.
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Affiliation(s)
- Anissa El Arfani
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
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Merckx E, Demuyser T, Bentea E, Van Liefferinge J, Albertini G, Deneyer L, Michiels T, Massie A. Lack of effect of Theiler's murine encephalomyelitis virus infection on system xc⁻. Neurosci Lett 2015; 593:124-8. [PMID: 25796181 DOI: 10.1016/j.neulet.2015.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 02/07/2023]
Abstract
Changes in the expression of xCT, the specific subunit of system xc(-) or the cystine/glutamate antiporter, have been associated with several neurological disorders and system xc(-) was recently proposed as a potential target for the development of new treatment strategies for multiple sclerosis (MS). In this study we used Theiler's murine encephalomyelitis virus (TMEV) infection, both in vitro and in vivo, as a model to further evaluate the involvement of system xc(-) in MS. Protein levels of xCT, as well as activity of system xc(-) were unaffected in RAW264.7 macrophages after infection with the demyelinating DA strain of TMEV. Also, protein expression of xCT remained stable in spinal cord and brain of FVB mice 1-2 and 6 weeks after intracranial injection of the DA strain of TMEV. These results demonstrate that TMEV infection of macrophages or FVB mice has no effect on system xc(-) and as such cannot be used as a model to study the involvement of system xc(-) in MS.
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Affiliation(s)
- Ellen Merckx
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Joeri Van Liefferinge
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Lauren Deneyer
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
| | - Thomas Michiels
- de Duve Institute, Université Catholique de Louvain, Avenue Hippocrate 74, 1200 Brussels, Belgium.
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
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26
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Bentea E, Sconce MD, Churchill MJ, Van Liefferinge J, Sato H, Meshul CK, Massie A. MPTP-induced parkinsonism in mice alters striatal and nigral xCT expression but is unaffected by the genetic loss of xCT. Neurosci Lett 2015; 593:1-6. [PMID: 25766755 DOI: 10.1016/j.neulet.2015.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/03/2015] [Accepted: 03/05/2015] [Indexed: 01/22/2023]
Abstract
Nigral cell loss in Parkinson's disease (PD) is associated with disturbed glutathione (GSH) and glutamate levels, leading to oxidative stress and excitotoxicity, respectively. System xc- is a plasma membrane antiporter that couples cystine import (amino acid that can be further used for the synthesis of GSH) with glutamate export to the extracellular environment, and can thus affect both oxidative stress and glutamate excitotoxicity. In the current study, we evaluated the involvement of system xc- in a progressive 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. Our results indicate that the expression of xCT (the specific subunit of system xc-) undergoes region-specific changes in MPTP-treated mice, with increased expression in the striatum, and decreased expression in the substantia nigra. Furthermore, mice lacking xCT were equally sensitive to the neurotoxic effects of MPTP compared to wild-type (WT) mice, as they demonstrate similar decreases in striatal dopamine content, striatal tyrosine hydroxylase (TH) expression, nigral TH immunopositive neurons and forelimb grip strength, five weeks after commencing MPTP treatment. Altogether, our data indicate that progressive lesioning with MPTP induces striatal and nigral dysregulation of system xc-. However, loss of system xc- does not affect MPTP-induced nigral dopaminergic neurodegeneration and motor impairment in mice.
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Affiliation(s)
- Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Michelle D Sconce
- Research Services, Neurocytology Laboratory, Veterans Affairs Medical Center, Portland, OR, USA
| | - Madeline J Churchill
- Research Services, Neurocytology Laboratory, Veterans Affairs Medical Center, Portland, OR, USA
| | - Joeri Van Liefferinge
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hideyo Sato
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology, Faculty of Medicine, Niigata University, Niigata, Japan
| | - Charles K Meshul
- Research Services, Neurocytology Laboratory, Veterans Affairs Medical Center, Portland, OR, USA; Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium.
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Mesci P, Zaïdi S, Lobsiger CS, Millecamps S, Escartin C, Seilhean D, Sato H, Mallat M, Boillée S. System xC- is a mediator of microglial function and its deletion slows symptoms in amyotrophic lateral sclerosis mice. ACTA ACUST UNITED AC 2014; 138:53-68. [PMID: 25384799 DOI: 10.1093/brain/awu312] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis is the most common adult-onset motor neuron disease and evidence from mice expressing amyotrophic lateral sclerosis-causing SOD1 mutations suggest that neurodegeneration is a non-cell autonomous process where microglial cells influence disease progression. However, microglial-derived neurotoxic factors still remain largely unidentified in amyotrophic lateral sclerosis. With excitotoxicity being a major mechanism proposed to cause motor neuron death in amyotrophic lateral sclerosis, our hypothesis was that excessive glutamate release by activated microglia through their system [Formula: see text] (a cystine/glutamate antiporter with the specific subunit xCT/Slc7a11) could contribute to neurodegeneration. Here we show that xCT expression is enriched in microglia compared to total mouse spinal cord and absent from motor neurons. Activated microglia induced xCT expression and during disease, xCT levels were increased in both spinal cord and isolated microglia from mutant SOD1 amyotrophic lateral sclerosis mice. Expression of xCT was also detectable in spinal cord post-mortem tissues of patients with amyotrophic lateral sclerosis and correlated with increased inflammation. Genetic deletion of xCT in mice demonstrated that activated microglia released glutamate mainly through system [Formula: see text]. Interestingly, xCT deletion also led to decreased production of specific microglial pro-inflammatory/neurotoxic factors including nitric oxide, TNFa and IL6, whereas expression of anti-inflammatory/neuroprotective markers such as Ym1/Chil3 were increased, indicating that xCT regulates microglial functions. In amyotrophic lateral sclerosis mice, xCT deletion surprisingly led to earlier symptom onset but, importantly, this was followed by a significantly slowed progressive disease phase, which resulted in more surviving motor neurons. These results are consistent with a deleterious contribution of microglial-derived glutamate during symptomatic disease. Therefore, we show that system [Formula: see text] participates in microglial reactivity and modulates amyotrophic lateral sclerosis motor neuron degeneration, revealing system [Formula: see text] inactivation, as a potential approach to slow amyotrophic lateral sclerosis disease progression after onset of clinical symptoms.
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Affiliation(s)
- Pinar Mesci
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Sakina Zaïdi
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Christian S Lobsiger
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Stéphanie Millecamps
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Carole Escartin
- 2 CEA, DSV, I2BM, MIRCen and CNRS URA2210, Fontenay-aux-Roses, France
| | - Danielle Seilhean
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Hideyo Sato
- 3 Department of Food and Applied Life Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata, Japan
| | - Michel Mallat
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Séverine Boillée
- 1 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
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Lewerenz J, Baxter P, Kassubek R, Albrecht P, Van Liefferinge J, Westhoff MA, Halatsch ME, Karpel-Massler G, Meakin PJ, Hayes JD, Aronica E, Smolders I, Ludolph AC, Methner A, Conrad M, Massie A, Hardingham GE, Maher P. Phosphoinositide 3-kinases upregulate system xc(-) via eukaryotic initiation factor 2α and activating transcription factor 4 - A pathway active in glioblastomas and epilepsy. Antioxid Redox Signal 2014; 20:2907-22. [PMID: 24219064 PMCID: PMC4038988 DOI: 10.1089/ars.2013.5455] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 10/25/2013] [Accepted: 11/12/2013] [Indexed: 01/08/2023]
Abstract
AIMS Phosphoinositide 3-kinases (PI3Ks) relay growth factor signaling and mediate cytoprotection and cell growth. The cystine/glutamate antiporter system xc(-) imports cystine while exporting glutamate, thereby promoting glutathione synthesis while increasing extracellular cerebral glutamate. The aim of this study was to analyze the pathway through which growth factor and PI3K signaling induce the cystine/glutamate antiporter system xc(-) and to demonstrate its biological significance for neuroprotection, cell growth, and epilepsy. RESULTS PI3Ks induce system xc(-) through glycogen synthase kinase 3β (GSK-3β) inhibition, general control non-derepressible-2-mediated eukaryotic initiation factor 2α phosphorylation, and the subsequent translational up-regulation of activating transcription factor 4. This pathway is essential for PI3Ks to modulate oxidative stress resistance of nerve cells and insulin-induced growth in fibroblasts. Moreover, the pathway is active in human glioblastoma cells. In addition, it is induced in primary cortical neurons in response to robust neuronal activity and in hippocampi from patients with temporal lobe epilepsy. INNOVATION Our findings further extend the concepts of how growth factors and PI3Ks induce neuroprotection and cell growth by adding a new branch to the signaling network downstream of GSK-3β, which, ultimately, leads to the induction of the cystine/glutamate antiporter system xc(-). Importantly, the induction of this pathway by neuronal activity and in epileptic hippocampi points to a potential role in epilepsy. CONCLUSION PI3K-regulated system xc(-) activity is not only involved in the stress resistance of neuronal cells and in cell growth by increasing the cysteine supply and glutathione synthesis, but also plays a role in the pathophysiology of tumor- and non-tumor-associated epilepsy by up-regulating extracellular cerebral glutamate.
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Affiliation(s)
- Jan Lewerenz
- Department of Neurology, Ulm University, Ulm, Germany
| | - Paul Baxter
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | | | - Philipp Albrecht
- Department of Neurology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Joeri Van Liefferinge
- Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | | | | | | | - Paul J. Meakin
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland, United Kingdom
| | - John D. Hayes
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland, United Kingdom
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- SEIN—Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands
| | - Ilse Smolders
- Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Axel Methner
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Mainz, Germany
| | - Marcus Conrad
- Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Ann Massie
- Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Giles E. Hardingham
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California
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Behavioral characterization of system xc- mutant mice. Behav Brain Res 2014; 265:1-11. [PMID: 24548853 DOI: 10.1016/j.bbr.2014.02.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/04/2014] [Accepted: 02/08/2014] [Indexed: 01/18/2023]
Abstract
The slc7a11 gene encodes xCT, an essential component of 'system xc-', a plasma membrane exchanger that imports cystine and exports glutamate. Slc7a11 is expressed primarily in the brain, but its role there is not clear. We performed behavioral tests on two different strains of homozygous slc7a11 mutant mice ('sut' and 'xCT'), as well as heteroallelic offspring of these two strains ('xCT/sut') and their associated genetic backgrounds. Homozygous sut mutant males showed reduced spontaneous alternation in spontaneous alternation tasks as well as reduced movement in an open field maze, but xCT and xCT/sut strains did not show significant changes in these tasks compared to appropriate controls. Neither xCT nor sut mutants showed differences from controls in rotarod tests. Female behavioral phenotypes were independent of estrus cycle stage. To ensure that homozygous xCT, sut, and xCT/sut strains all represent protein null alleles, we measured whole brain xCT protein levels using immunoblots. xCT, sut and xCT/sut strains showed no detectable xCT protein expression, confirming them as null alleles. Previously published microdialysis experiments showed reduced striatal glutamate in xCT mutants. Using the same methods, we measured reduced interstitial glutamate levels in the striatum but not cerebellum of sut mutants. However, we detected no glutamate change in the striatum or cerebellum of sut/xCT mice. We detected no changes in whole brain EAAT-1, -2, or -3 expression. We conclude that the behavioral and chemical differences exist between slc7a11 mutant strains, but we were unable to definitively attribute any of these differences to loss of system xc-.
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Glutamate transporters in the biology of malignant gliomas. Cell Mol Life Sci 2013; 71:1839-54. [PMID: 24281762 DOI: 10.1007/s00018-013-1521-z] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/22/2013] [Accepted: 11/11/2013] [Indexed: 12/11/2022]
Abstract
Malignant gliomas are relentless tumors that offer a dismal clinical prognosis. They develop many biological advantages that allow them to grow and survive in the unique environment of the brain. The glutamate transporters system x c (-) and excitatory amino acid transporters (EAAT) are emerging as key players in the biology and malignancy of these tumors. Gliomas manipulate glutamate transporter expression and function to alter glutamate homeostasis in the brain, which supports their own growth, invasion, and survival. As a consequence, malignant cells are able to quickly destroy and invade surrounding normal brain. Recent findings are painting a larger picture of these transporters in glioma biology, and as such are providing opportunities for clinical intervention for patients. This review will detail the current understanding of glutamate transporters in the biology of malignant gliomas and highlight some of the unique aspects of these tumors that make them so devastating and difficult to treat.
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Lewerenz J, Hewett SJ, Huang Y, Lambros M, Gout PW, Kalivas PW, Massie A, Smolders I, Methner A, Pergande M, Smith SB, Ganapathy V, Maher P. The cystine/glutamate antiporter system x(c)(-) in health and disease: from molecular mechanisms to novel therapeutic opportunities. Antioxid Redox Signal 2013; 18:522-55. [PMID: 22667998 PMCID: PMC3545354 DOI: 10.1089/ars.2011.4391] [Citation(s) in RCA: 656] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The antiporter system x(c)(-) imports the amino acid cystine, the oxidized form of cysteine, into cells with a 1:1 counter-transport of glutamate. It is composed of a light chain, xCT, and a heavy chain, 4F2 heavy chain (4F2hc), and, thus, belongs to the family of heterodimeric amino acid transporters. Cysteine is the rate-limiting substrate for the important antioxidant glutathione (GSH) and, along with cystine, it also forms a key redox couple on its own. Glutamate is a major neurotransmitter in the central nervous system (CNS). By phylogenetic analysis, we show that system x(c)(-) is a rather evolutionarily new amino acid transport system. In addition, we summarize the current knowledge regarding the molecular mechanisms that regulate system x(c)(-), including the transcriptional regulation of the xCT light chain, posttranscriptional mechanisms, and pharmacological inhibitors of system x(c)(-). Moreover, the roles of system x(c)(-) in regulating GSH levels, the redox state of the extracellular cystine/cysteine redox couple, and extracellular glutamate levels are discussed. In vitro, glutamate-mediated system x(c)(-) inhibition leads to neuronal cell death, a paradigm called oxidative glutamate toxicity, which has successfully been used to identify neuroprotective compounds. In vivo, xCT has a rather restricted expression pattern with the highest levels in the CNS and parts of the immune system. System x(c)(-) is also present in the eye. Moreover, an elevated expression of xCT has been reported in cancer. We highlight the diverse roles of system x(c)(-) in the regulation of the immune response, in various aspects of cancer and in the eye and the CNS.
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Affiliation(s)
- Jan Lewerenz
- Department of Neurology, University of Ulm, Ulm, Germany.
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Abstract
Breast cancers are the most common source of metastases to bone, of which cancer-induced bone pain is a frequent pathological feature. Cancer-induced bone pain is a unique pain state with multiple determinants that remains to be well understood and managed. Current standard treatments are limited by dose-dependent side effects that can reduce the quality of life of patients. Glutamate is a neurotransmitter and bone cell-signalling molecule that is released via the system x(c)(-) cystine/glutamate antiporter from cancer cell types that frequently metastasize to bone, including breast cancers. In cancer cells, glutamate release is understood to be a side effect of the cellular response to oxidative stress that upregulates the expression and activity of system x(c)(-) to promote the increased import of cystine. Attenuation of glutamate release from cancer cells has been demonstrated to result in reductions in associated cancer-induced bone pain in animal models. This review examines the clinical implications of attenuating cystine uptake and glutamate release in the treatment of cancer-induced bone pain.
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Affiliation(s)
- Robert G Ungard
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8N 3Z5, Canada
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Bridges R, Lutgen V, Lobner D, Baker DA. Thinking outside the cleft to understand synaptic activity: contribution of the cystine-glutamate antiporter (System xc-) to normal and pathological glutamatergic signaling. Pharmacol Rev 2012; 64:780-802. [PMID: 22759795 PMCID: PMC3400835 DOI: 10.1124/pr.110.003889] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
System x(c)(-) represents an intriguing target in attempts to understand the pathological states of the central nervous system. Also called a cystine-glutamate antiporter, system x(c)(-) typically functions by exchanging one molecule of extracellular cystine for one molecule of intracellular glutamate. Nonvesicular glutamate released during cystine-glutamate exchange activates extrasynaptic glutamate receptors in a manner that shapes synaptic activity and plasticity. These findings contribute to the intriguing possibility that extracellular glutamate is regulated by a complex network of release and reuptake mechanisms, many of which are unique to glutamate and rarely depicted in models of excitatory signaling. Because system x(c)(-) is often expressed on non-neuronal cells, the study of cystine-glutamate exchange may advance the emerging viewpoint that glia are active contributors to information processing in the brain. It is noteworthy that system x(c)(-) is at the interface between excitatory signaling and oxidative stress, because the uptake of cystine that results from cystine-glutamate exchange is critical in maintaining the levels of glutathione, a critical antioxidant. As a result of these dual functions, system x(c)(-) has been implicated in a wide array of central nervous system diseases ranging from addiction to neurodegenerative disorders to schizophrenia. In the current review, we briefly discuss the major cellular components that regulate glutamate homeostasis, including glutamate release by system x(c)(-). This is followed by an in-depth discussion of system x(c)(-) as it relates to glutamate release, cystine transport, and glutathione synthesis. Finally, the role of system x(c)(-) is surveyed across a number of psychiatric and neurodegenerative disorders.
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Affiliation(s)
- Richard Bridges
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana, USA
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Walker RH, Moore C, Davies G, Dirling LB, Koch RJ, Meshul CK. Effects of subthalamic nucleus lesions and stimulation upon corticostriatal afferents in the 6-hydroxydopamine-lesioned rat. PLoS One 2012; 7:e32919. [PMID: 22427909 PMCID: PMC3299711 DOI: 10.1371/journal.pone.0032919] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 02/06/2012] [Indexed: 12/27/2022] Open
Abstract
Abnormalities of striatal glutamate neurotransmission may play a role in the pathophysiology of Parkinson's disease and may respond to neurosurgical interventions, specifically stimulation or lesioning of the subthalamic nucleus (STN). The major glutamatergic afferent pathways to the striatum are from the cortex and thalamus, and are thus likely to be sources of striatal neuronally-released glutamate. Corticostriatal terminals can be distinguished within the striatum at the electron microscopic level as their synaptic vesicles contain the vesicular glutamate transporter, VGLUT1. The majority of terminals which are immunolabeled for glutamate but are not VGLUT1 positive are likely to be thalamostriatal afferents. We compared the effects of short term, high frequency, STN stimulation and lesioning in 6-hydroxydopamine (6OHDA)-lesioned rats upon striatal terminals immunolabeled for both presynaptic glutamate and VGLUT1. 6OHDA lesions resulted in a small but significant increase in the proportions of VGLUT1-labeled terminals making synapses on dendritic shafts rather than spines. STN stimulation for one hour, but not STN lesions, increased the proportion of synapses upon spines. The density of presynaptic glutamate immuno-gold labeling was unchanged in both VGLUT1-labeled and -unlabeled terminals in 6OHDA-lesioned rats compared to controls. Rats with 6OHDA lesions+STN stimulation showed a decrease in nerve terminal glutamate immuno-gold labeling in both VGLUT1-labeled and -unlabeled terminals. STN lesions resulted in a significant decrease in the density of presynaptic immuno-gold-labeled glutamate only in VGLUT1-labeled terminals. STN interventions may achieve at least part of their therapeutic effect in PD by normalizing the location of corticostriatal glutamatergic terminals and by altering striatal glutamatergic neurotransmission.
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Affiliation(s)
- Ruth H Walker
- Department of Neurology, James J Peters Veterans Affairs Medical Center, Bronx, New York, United States of America.
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Liu X, Resch J, Rush T, Lobner D. Functional upregulation of system xc− by fibroblast growth factor-2. Neuropharmacology 2012; 62:901-6. [DOI: 10.1016/j.neuropharm.2011.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
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Loss of system x(c)- does not induce oxidative stress but decreases extracellular glutamate in hippocampus and influences spatial working memory and limbic seizure susceptibility. J Neurosci 2011; 31:5792-803. [PMID: 21490221 DOI: 10.1523/jneurosci.5465-10.2011] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
System x(c)- exchanges intracellular glutamate for extracellular cystine, giving it a potential role in intracellular glutathione synthesis and nonvesicular glutamate release. We report that mice lacking the specific xCT subunit of system x(c)- (xCT(-/-)) do not have a lower hippocampal glutathione content, increased oxidative stress or brain atrophy, nor exacerbated spatial reference memory deficits with aging. Together these results indicate that loss of system x(c)- does not induce oxidative stress in vivo. Young xCT(-/-) mice did however display a spatial working memory deficit. Interestingly, we observed significantly lower extracellular hippocampal glutamate concentrations in xCT(-/-) mice compared to wild-type littermates. Moreover, intrahippocampal perfusion with system x(c)- inhibitors lowered extracellular glutamate, whereas the system x(c)- activator N-acetylcysteine elevated extracellular glutamate in the rat hippocampus. This indicates that system x(c)- may be an interesting target for pathologies associated with excessive extracellular glutamate release in the hippocampus. Correspondingly, xCT deletion in mice elevated the threshold for limbic seizures and abolished the proconvulsive effects of N-acetylcysteine. These novel findings sustain that system x(c)-) is an important source of extracellular glutamate in the hippocampus. System x(c)(-) is required for optimal spatial working memory, but its inactivation is clearly beneficial to decrease susceptibility for limbic epileptic seizures.
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Pampliega O, Domercq M, Soria FN, Villoslada P, Rodríguez-Antigüedad A, Matute C. Increased expression of cystine/glutamate antiporter in multiple sclerosis. J Neuroinflammation 2011; 8:63. [PMID: 21639880 PMCID: PMC3117706 DOI: 10.1186/1742-2094-8-63] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 06/03/2011] [Indexed: 11/10/2022] Open
Abstract
Background Glutamate excitotoxicity contributes to oligodendrocyte and tissue damage in multiple sclerosis (MS). Intriguingly, glutamate level in plasma and cerebrospinal fluid of MS patients is elevated, a feature which may be related to the pathophysiology of this disease. In addition to glutamate transporters, levels of extracellular glutamate are controlled by cystine/glutamate antiporter xc-, an exchanger that provides intracellular cystine for production of glutathione, the major cellular antioxidant. The objective of this study was to analyze the role of the system xc- in glutamate homeostasis alterations in MS pathology. Methods Primary cultures of human monocytes and the cell line U-937 were used to investigate the mechanism of glutamate release. Expression of cystine glutamate exchanger (xCT) was quantified by quantitative PCR, Western blot, flow cytometry and immunohistochemistry in monocytes in vitro, in animals with experimental autoimmune encephalomyelitis (EAE), the animal model of MS, and in samples of MS patients. Results and discussion We show here that human activated monocytes release glutamate through cystine/glutamate antiporter xc- and that the expression of the catalytic subunit xCT is upregulated as a consequence of monocyte activation. In addition, xCT expression is also increased in EAE and in the disease proper. In the later, high expression of xCT occurs both in the central nervous system (CNS) and in peripheral blood cells. In particular, cells from monocyte-macrophage-microglia lineage have higher xCT expression in MS and in EAE, indicating that immune activation upregulates xCT levels, which may result in higher glutamate release and contribution to excitotoxic damage to oligodendrocytes. Conclusions Together, these results reveal that increased expression of the cystine/glutamate antiporter system xc- in MS provides a link between inflammation and excitotoxicity in demyelinating diseases.
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Affiliation(s)
- Olatz Pampliega
- Neurotek-UPV/EHU, Parque Tecnológico de Bizkaia, Zamudio, Bizkaia, Spain
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Massie A, Schallier A, Kim SW, Fernando R, Kobayashi S, Beck H, Bundel DD, Vermoesen K, Bannai S, Smolders I, Conrad M, Plesnila N, Sato H, Michotte Y. Dopaminergic neurons of system x
c
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‐deficient mice are highly protected against 6‐hydroxydopamine‐induced toxicity. FASEB J 2010; 25:1359-69. [DOI: 10.1096/fj.10-177212] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ann Massie
- Department of Pharmaceutical Chemistry and Drug AnalysisResearch Group Experimental Pharmacology, Vrije Universiteit Brussel Brussels Belgium
| | - Anneleen Schallier
- Department of Pharmaceutical Chemistry and Drug AnalysisResearch Group Experimental Pharmacology, Vrije Universiteit Brussel Brussels Belgium
| | | | - Ruani Fernando
- Department of Medical Biochemistry and BiophysicsKarolinska Institutet Stockholm Sweden
| | - Sho Kobayashi
- Department of Food and Applied Life SciencesFaculty of Agriculture, Yamagata University Tsuruoka Yamagata Japan
| | - Heike Beck
- Walter Brendel Center of Experimental Medicine, Ludwig‐Maximilians‐University Munich Germany
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry and Drug AnalysisResearch Group Experimental Pharmacology, Vrije Universiteit Brussel Brussels Belgium
| | - Katia Vermoesen
- Department of Pharmaceutical Chemistry and Drug AnalysisResearch Group Experimental Pharmacology, Vrije Universiteit Brussel Brussels Belgium
| | - Shiro Bannai
- Department of Food and Applied Life SciencesFaculty of Agriculture, Yamagata University Tsuruoka Yamagata Japan
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug AnalysisResearch Group Experimental Pharmacology, Vrije Universiteit Brussel Brussels Belgium
| | - Marcus Conrad
- Helmholtz Center MunichInstitute of Clinical Molecular Biology and Tumor Genetics Munich Germany
| | | | - Hideyo Sato
- Department of Food and Applied Life SciencesFaculty of Agriculture, Yamagata University Tsuruoka Yamagata Japan
| | - Yvette Michotte
- Department of Pharmaceutical Chemistry and Drug AnalysisResearch Group Experimental Pharmacology, Vrije Universiteit Brussel Brussels Belgium
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Massie A, Goursaud S, Schallier A, Vermoesen K, Meshul CK, Hermans E, Michotte Y. Time-dependent changes in GLT-1 functioning in striatum of hemi-Parkinson rats. Neurochem Int 2010; 57:572-8. [PMID: 20643175 DOI: 10.1016/j.neuint.2010.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 06/29/2010] [Accepted: 07/08/2010] [Indexed: 10/19/2022]
Abstract
Striatal dopamine loss in Parkinson's disease is accompanied by a dysregulation of corticostriatal glutamatergic neurotransmission. Within this study, we investigated striatal expression and activity of the glial high-affinity Na(+)/K(+)-dependent glutamate transporters, GLT-1 and GLAST, in the 6-hydroxydopamine hemi-Parkinson rat model at different time points after unilateral 6-hydroxydopamine injection into the medial forebrain bundle. Using semi-quantitative Western blotting and an ex vivo D-[(3)H]-aspartate uptake assay, we showed a time-dependent bilateral effect of unilateral 6-hydroxydopamine lesioning on the expression as well as activity of GLT-1. At 3 and 12 weeks post-lesion, striatal GLT-1 function was bilaterally upregulated whereas at 5 weeks there was no change. Even though our data do not allow a straightforward conclusion as for the role of glutamate transporters in the pathogenesis of the disease, they do clearly demonstrate a link between disturbed glutamatergic neurotransmission and glutamate transporter functioning in the striatum of a rat model for Parkinson's disease.
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Affiliation(s)
- Ann Massie
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels, Belgium
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