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Salzinger A, Ramesh V, Das Sharma S, Chandran S, Thangaraj Selvaraj B. Neuronal Circuit Dysfunction in Amyotrophic Lateral Sclerosis. Cells 2024; 13:792. [PMID: 38786016 PMCID: PMC11120636 DOI: 10.3390/cells13100792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
The primary neural circuit affected in Amyotrophic Lateral Sclerosis (ALS) patients is the corticospinal motor circuit, originating in upper motor neurons (UMNs) in the cerebral motor cortex which descend to synapse with the lower motor neurons (LMNs) in the spinal cord to ultimately innervate the skeletal muscle. Perturbation of these neural circuits and consequent loss of both UMNs and LMNs, leading to muscle wastage and impaired movement, is the key pathophysiology observed. Despite decades of research, we are still lacking in ALS disease-modifying treatments. In this review, we document the current research from patient studies, rodent models, and human stem cell models in understanding the mechanisms of corticomotor circuit dysfunction and its implication in ALS. We summarize the current knowledge about cortical UMN dysfunction and degeneration, altered excitability in LMNs, neuromuscular junction degeneration, and the non-cell autonomous role of glial cells in motor circuit dysfunction in relation to ALS. We further highlight the advances in human stem cell technology to model the complex neural circuitry and how these can aid in future studies to better understand the mechanisms of neural circuit dysfunction underpinning ALS.
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Affiliation(s)
- Andrea Salzinger
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Vidya Ramesh
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Shreya Das Sharma
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Siddharthan Chandran
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- Anne Rowling Regenerative Neurology Clinic (ARRNC), University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Bhuvaneish Thangaraj Selvaraj
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- Anne Rowling Regenerative Neurology Clinic (ARRNC), University of Edinburgh, Edinburgh EH16 4SB, UK
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2
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Sun Z, Zhang B, Peng Y. Development of novel treatments for amyotrophic lateral sclerosis. Metab Brain Dis 2024; 39:467-482. [PMID: 38078970 DOI: 10.1007/s11011-023-01334-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 12/01/2023] [Indexed: 03/22/2024]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that causes paralysis whose etiology and pathogenesis have not been fully elucidated. Presently it is incurable and rapidly progressive with a survival of 2-5 years from onset, and no treatments could cure it. Therefore, it is urgent to identify which therapeutic target(s) are more promising to develop treatments that could effectively treat ALS. So far, more than 90 novel treatments for ALS patients have been registered on ClinicalTrials.gov, of which 23 are in clinical trials, 12 have been terminated and the rest suspended. This review will systematically summarize the possible targets of these novel treatments under development or failing based on published literature and information released by sponsors, so as to provide basis and support for subsequent drug research and development.
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Affiliation(s)
- Zhuo Sun
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
- Department of Pharmacy, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Shuaifuyuan, Dongcheng District, Beijing, 100730, China
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Beijing, 100730, China
| | - Bo Zhang
- Department of Pharmacy, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Shuaifuyuan, Dongcheng District, Beijing, 100730, China.
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Beijing, 100730, China.
| | - Ying Peng
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
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Yuan Y, Bailey JM, Rivera-Lopez GM, Atchison WD. Preferential potentiation of AMPA-mediated currents in brainstem hypoglossal motoneurons by subchronic exposure of mice expressing the human superoxide dismutase 1 G93A gene mutation to neurotoxicant methylmercury in vivo. Neurotoxicology 2024; 100:72-84. [PMID: 38065418 PMCID: PMC10877233 DOI: 10.1016/j.neuro.2023.12.002] [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: 05/12/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/18/2023]
Abstract
The exact causes of Amyotrophic lateral sclerosis (ALS), a progressive and fatal neurological disorder due to loss of upper and/or lower motoneurons, remain elusive. Gene-environment interactions are believed to be an important factor in the development of ALS. We previously showed that in vivo exposure of mice overexpressing the human superoxide dismutase 1 (hSOD1) gene mutation (hSOD1G93A; G93A), a mouse model for ALS, to environmental neurotoxicant methylmercury (MeHg) accelerated the onset of ALS-like phenotype. Here we examined the time-course of effects of MeHg on AMPA receptor (AMPAR)-mediated currents in hypoglossal motoneurons in brainstem slices prepared from G93A, hSOD1wild-type (hWT) and non-carrier WT mice following in vivo exposure to MeHg. Mice were exposed daily to 3 ppm (approximately 0.7 mg/kg/day) MeHg via drinking water beginning at postnatal day 28 (P28) and continued until P47, 64 or 84, then acute brainstem slices were prepared, and spontaneous excitatory postsynaptic currents (sEPSCs) or AMPA-evoked currents were examined using whole cell patch-clamp recording technique. Brainstem slices of untreated littermates were prepared at the same time points to serve as control. MeHg exposure had no significant effect on either sEPSCs or AMPA-evoked currents in slices from hWT or WT mice during any of those exposure time periods under our experimental conditions. MeHg also did not cause any significant effect on sEPSCs or AMPA-currents in G93A hypoglossal motoneurons at P47 and P64. However, at P84, MeHg significantly increased amplitudes of both sEPSCs and AMPA-evoked currents in hypoglossal motineurons from G93A mice (p < 0.05), but not the sEPSC frequency, suggesting a postsynaptic action on AMPARs. MeHg exposure did not cause any significant effect on GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs). Therefore, MeHg exposure in vivo caused differential effects on AMPARs in hypoglossal motoneurons from mice with different genetic backgrounds. MeHg appears to preferentially stimulate the AMPAR-mediated currents in G93A hypoglossal motoneurons in an exposure time-dependent manner, which may contribute to the AMPAR-mediated motoneuron excitotoxicity, thereby facilitating development of ALS-like phenotype.
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Affiliation(s)
- Yukun Yuan
- Department of Pharmacology/Toxicology, Michigan State University, Life Sciences Building, 1355 Bogue Street, East Lansing, MI 48824-1317, USA.
| | - Jordan M Bailey
- Department of Pharmacology/Toxicology, Michigan State University, Life Sciences Building, 1355 Bogue Street, East Lansing, MI 48824-1317, USA
| | - Gretchen M Rivera-Lopez
- Department of Pharmacology/Toxicology, Michigan State University, Life Sciences Building, 1355 Bogue Street, East Lansing, MI 48824-1317, USA
| | - William D Atchison
- Department of Pharmacology/Toxicology, Michigan State University, Life Sciences Building, 1355 Bogue Street, East Lansing, MI 48824-1317, USA
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Vukolova MN, Yen LY, Khmyz MI, Sobolevsky AI, Yelshanskaya MV. Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis-emerging role of AMPA and kainate subtypes of ionotropic glutamate receptors. Front Cell Dev Biol 2023; 11:1252953. [PMID: 38033869 PMCID: PMC10683763 DOI: 10.3389/fcell.2023.1252953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 10/05/2023] [Indexed: 12/02/2023] Open
Abstract
Ionotropic glutamate receptors (iGluRs) mediate the majority of excitatory neurotransmission and are implicated in various neurological disorders. In this review, we discuss the role of the two fastest iGluRs subtypes, namely, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors, in the pathogenesis and treatment of Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis. Although both AMPA and kainate receptors represent promising therapeutic targets for the treatment of these diseases, many of their antagonists show adverse side effects. Further studies of factors affecting the selective subunit expression and trafficking of AMPA and kainate receptors, and a reasonable approach to their regulation by the recently identified novel compounds remain promising directions for pharmacological research.
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Affiliation(s)
- Marina N. Vukolova
- Department of Pathophysiology, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Laura Y. Yen
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
- Cellular and Molecular Physiology and Biophysics Graduate Program, Columbia University, New York, NY, United States
| | - Margarita I. Khmyz
- N. V. Sklifosovsky Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Alexander I. Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
| | - Maria V. Yelshanskaya
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
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Jomova K, Makova M, Alomar SY, Alwasel SH, Nepovimova E, Kuca K, Rhodes CJ, Valko M. Essential metals in health and disease. Chem Biol Interact 2022; 367:110173. [PMID: 36152810 DOI: 10.1016/j.cbi.2022.110173] [Citation(s) in RCA: 156] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/10/2022] [Accepted: 09/05/2022] [Indexed: 11/03/2022]
Abstract
In total, twenty elements appear to be essential for the correct functioning of the human body, half of which are metals and half are non-metals. Among those metals that are currently considered to be essential for normal biological functioning are four main group elements, sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca), and six d-block transition metal elements, manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn) and molybdenum (Mo). Cells have developed various metallo-regulatory mechanisms for maintaining a necessary homeostasis of metal-ions for diverse cellular processes, most importantly in the central nervous system. Since redox active transition metals (for example Fe and Cu) may participate in electron transfer reactions, their homeostasis must be carefully controlled. The catalytic behaviour of redox metals which have escaped control, e.g. via the Fenton reaction, results in the formation of reactive hydroxyl radicals, which may cause damage to DNA, proteins and membranes. Transition metals are integral parts of the active centers of numerous enzymes (e.g. Cu,Zn-SOD, Mn-SOD, Catalase) which catalyze chemical reactions at physiologically compatible rates. Either a deficiency, or an excess of essential metals may result in various disease states arising in an organism. Some typical ailments that are characterized by a disturbed homeostasis of redox active metals include neurological disorders (Alzheimer's, Parkinson's and Huntington's disorders), mental health problems, cardiovascular diseases, cancer, and diabetes. To comprehend more deeply the mechanisms by which essential metals, acting either alone or in combination, and/or through their interaction with non-essential metals (e.g. chromium) function in biological systems will require the application of a broader, more interdisciplinary approach than has mainly been used so far. It is clear that a stronger cooperation between bioinorganic chemists and biophysicists - who have already achieved great success in understanding the structure and role of metalloenzymes in living systems - with biologists, will access new avenues of research in the systems biology of metal ions. With this in mind, the present paper reviews selected chemical and biological aspects of metal ions and their possible interactions in living systems under normal and pathological conditions.
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Affiliation(s)
- Klaudia Jomova
- Department of Chemistry, Faculty of Natural Sciences and Informatics, Constantine The Philosopher University in Nitra, 949 01, Nitra, Slovakia
| | - Marianna Makova
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, 812 37, Bratislava, Slovakia
| | - Suliman Y Alomar
- King Saud University, Zoology Department, College of Science, Riyadh, 11451, Saudi Arabia
| | - Saleh H Alwasel
- King Saud University, Zoology Department, College of Science, Riyadh, 11451, Saudi Arabia
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, 50003 Hradec Kralove, Czech Republic
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, 50003 Hradec Kralove, Czech Republic; Biomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | | | - Marian Valko
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, 812 37, Bratislava, Slovakia; King Saud University, Zoology Department, College of Science, Riyadh, 11451, Saudi Arabia.
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Widagdo J, Udagedara S, Bhembre N, Tan JZA, Neureiter L, Huang J, Anggono V, Lee M. Familial ALS-associated SFPQ variants promote the formation of SFPQ cytoplasmic aggregates in primary neurons. Open Biol 2022; 12:220187. [PMID: 36168806 PMCID: PMC9516340 DOI: 10.1098/rsob.220187] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Splicing factor proline- and glutamine-rich (SFPQ) is a nuclear RNA-binding protein that is involved in a wide range of physiological processes including neuronal development and homeostasis. However, the mislocalization and cytoplasmic aggregation of SFPQ are associated with the pathophysiology of amyotrophic lateral sclerosis (ALS). We have previously reported that zinc mediates SFPQ polymerization and promotes the formation of cytoplasmic aggregates in neurons. Here we characterize two familial ALS (fALS)-associated SFPQ variants, which cause amino acid substitutions in the proximity of the SFPQ zinc-coordinating centre (N533H and L534I). Both mutants display increased zinc-binding affinities, which can be explained by the presence of a second zinc-binding site revealed by the 1.83 Å crystal structure of the human SFPQ L534I mutant. Overexpression of these fALS-associated mutants significantly increases the number of SFPQ cytoplasmic aggregates in primary neurons. Although they do not affect the density of dendritic spines, the presence of SFPQ cytoplasmic aggregates causes a marked reduction in the levels of the GluA1, but not the GluA2 subunit of AMPA-type glutamate receptors on the neuronal surface. Taken together, our data demonstrate that fALS-associated mutations enhance the propensity of SFPQ to bind zinc and form aggregates, leading to the dysregulation of AMPA receptor subunit composition, which may contribute to neuronal dysfunction in ALS.
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Affiliation(s)
- Jocelyn Widagdo
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Saumya Udagedara
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Nishita Bhembre
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jing Zhi Anson Tan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Lara Neureiter
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jie Huang
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Victor Anggono
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mihwa Lee
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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The Biogenesis of miRNAs and Their Role in the Development of Amyotrophic Lateral Sclerosis. Cells 2022; 11:cells11030572. [PMID: 35159383 PMCID: PMC8833997 DOI: 10.3390/cells11030572] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/02/2022] [Accepted: 02/05/2022] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects upper and lower motor neurons. As there is no effective treatment for ALS, it is particularly important to screen key gene therapy targets. The identifications of microRNAs (miRNAs) have completely changed the traditional view of gene regulation. miRNAs are small noncoding single-stranded RNA molecules involved in the regulation of post-transcriptional gene expression. Recent advances also indicate that miRNAs are biomarkers in many diseases, including neurodegenerative diseases. In this review, we summarize recent advances regarding the mechanisms underlying the role of miRNAs in ALS pathogenesis and its application to gene therapy for ALS. The potential of miRNAs to target diverse pathways opens a new avenue for ALS therapy.
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Akamatsu M, Yamashita T, Teramoto S, Huang Z, Lynch J, Toda T, Niu L, Kwak S. Testing of the therapeutic efficacy and safety of AMPA receptor RNA aptamers in an ALS mouse model. Life Sci Alliance 2022; 5:5/4/e202101193. [PMID: 35022247 PMCID: PMC8761490 DOI: 10.26508/lsa.202101193] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 11/24/2022] Open
Abstract
In motor neurons of sporadic amyotrophic lateral sclerosis (ALS) patients, the RNA editing at the glutamine/arginine site of the GluA2 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors is defective or incomplete. As a result, AMPA receptors containing the abnormally expressed, unedited isoform of GluA2 are highly Ca2+-permeable, and are responsible for mediating abnormal Ca2+ influx, thereby triggering motor neuron degeneration and cell death. Thus, blocking the AMPA receptor-mediated, abnormal Ca2+ influx is a potential therapeutic strategy for treatment of sporadic ALS. Here, we report a study of the efficacy and safety of two RNA aptamers targeting AMPA receptors on the ALS phenotype of AR2 mice. A 12-wk continuous, intracerebroventricular infusion of aptamers to AR2 mice reduced the progression of motor dysfunction, normalized TDP-43 mislocalization, and prevented death of motor neurons. Our results demonstrate that the use of AMPA receptor aptamers as a novel class of AMPA receptor antagonists is a promising strategy for developing an ALS treatment approach.
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Affiliation(s)
- Megumi Akamatsu
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Takenari Yamashita
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sayaka Teramoto
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Neurology, Tokyo Medical University, Tokyo, Japan
| | - Zhen Huang
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, USA
| | - Janet Lynch
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, USA
| | - Tatsushi Toda
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Li Niu
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, USA
| | - Shin Kwak
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan .,Department of Neurology, Tokyo Medical University, Tokyo, Japan
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Guo C, Ma YY. Calcium Permeable-AMPA Receptors and Excitotoxicity in Neurological Disorders. Front Neural Circuits 2021; 15:711564. [PMID: 34483848 PMCID: PMC8416103 DOI: 10.3389/fncir.2021.711564] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/23/2021] [Indexed: 12/13/2022] Open
Abstract
Excitotoxicity is one of the primary mechanisms of cell loss in a variety of diseases of the central and peripheral nervous systems. Other than the previously established signaling pathways of excitotoxicity, which depend on the excessive release of glutamate from axon terminals or over-activation of NMDA receptors (NMDARs), Ca2+ influx-triggered excitotoxicity through Ca2+-permeable (CP)-AMPA receptors (AMPARs) is detected in multiple disease models. In this review, both acute brain insults (e.g., brain trauma or spinal cord injury, ischemia) and chronic neurological disorders, including Epilepsy/Seizures, Huntington’s disease (HD), Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), chronic pain, and glaucoma, are discussed regarding the CP-AMPAR-mediated excitotoxicity. Considering the low expression or absence of CP-AMPARs in most cells, specific manipulation of the CP-AMPARs might be a more plausible strategy to delay the onset and progression of pathological alterations with fewer side effects than blocking NMDARs.
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Affiliation(s)
- Changyong Guo
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Yao-Ying Ma
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
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Abstract
The brain is one of the organs that are preferentially targeted by adenosine-to-inosine (A-to-I) RNA editing, a posttranscriptional modification. This chemical modification affects neuronal development and functions at multiple levels, leading to normal brain homeostasis by increasing the complexity of the transcriptome. This includes modulation of the properties of ion channel and neurotransmitter receptors by recoding, redirection of miRNA targets by changing sequence complementarity, and suppression of immune response by altering RNA structure. Therefore, from another perspective, it appears that the brain is highly vulnerable to dysregulation of A-to-I RNA editing. Here, we focus on how aberrant A-to-I RNA editing is involved in neurological and neurodegenerative diseases of humans including epilepsy, amyotrophic lateral sclerosis, psychiatric disorders, developmental disorders, brain tumors, and encephalopathy caused by autoimmunity. In addition, we provide information regarding animal models to better understand the mechanisms behind disease phenotype.
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Affiliation(s)
- Pedro Henrique Costa Cruz
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yukio Kawahara
- Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.
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Morello G, Gentile G, Spataro R, Spampinato AG, Guarnaccia M, Salomone S, La Bella V, Conforti FL, Cavallaro S. Genomic Portrait of a Sporadic Amyotrophic Lateral Sclerosis Case in a Large Spinocerebellar Ataxia Type 1 Family. J Pers Med 2020; 10:jpm10040262. [PMID: 33276461 PMCID: PMC7712010 DOI: 10.3390/jpm10040262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 11/17/2022] Open
Abstract
Background: Repeat expansions in the spinocerebellar ataxia type 1 (SCA1) gene ATXN1 increases the risk for amyotrophic lateral sclerosis (ALS), supporting a relationship between these disorders. We recently reported the co-existence, in a large SCA1 family, of a clinically definite ALS individual bearing an intermediate ATXN1 expansion and SCA1 patients with a full expansion, some of which manifested signs of lower motor neuron involvement. Methods: In this study, we employed a systems biology approach that integrated multiple genomic analyses of the ALS patient and some SCA1 family members. Results: Our analysis identified common and distinctive candidate genes/variants and related biological processes that, in addition to or in combination with ATXN1, may contribute to motor neuron degeneration phenotype. Among these, we distinguished ALS-specific likely pathogenic variants in TAF15 and C9ORF72, two ALS-linked genes involved in the regulation of RNA metabolism, similarly to ATXN1, suggesting a selective role for this pathway in ALS pathogenesis. Conclusions: Overall, our work supports the utility to apply personal genomic information for characterizing complex disease phenotypes.
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Affiliation(s)
- Giovanna Morello
- Institute for Research and Biomedical Innovation (IRIB), Italian National Research Council (CNR), Via Paolo Gaifami, 18, 95125 Catania, Italy; (G.M.); (G.G.); (A.G.S.); (M.G.)
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95123 Catania, Italy;
| | - Giulia Gentile
- Institute for Research and Biomedical Innovation (IRIB), Italian National Research Council (CNR), Via Paolo Gaifami, 18, 95125 Catania, Italy; (G.M.); (G.G.); (A.G.S.); (M.G.)
| | - Rossella Spataro
- ALS Clinical Research Center and Neurochemistry Laboratory, BioNeC, University of Palermo, 90127 Palermo, Italy; (R.S.); (V.L.B.)
| | - Antonio Gianmaria Spampinato
- Institute for Research and Biomedical Innovation (IRIB), Italian National Research Council (CNR), Via Paolo Gaifami, 18, 95125 Catania, Italy; (G.M.); (G.G.); (A.G.S.); (M.G.)
- Department of Mathematics and Computer Science, University of Catania, 95123 Catania, Italy
| | - Maria Guarnaccia
- Institute for Research and Biomedical Innovation (IRIB), Italian National Research Council (CNR), Via Paolo Gaifami, 18, 95125 Catania, Italy; (G.M.); (G.G.); (A.G.S.); (M.G.)
| | - Salvatore Salomone
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95123 Catania, Italy;
| | - Vincenzo La Bella
- ALS Clinical Research Center and Neurochemistry Laboratory, BioNeC, University of Palermo, 90127 Palermo, Italy; (R.S.); (V.L.B.)
| | - Francesca Luisa Conforti
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Arcavacata di Rende, 87036 Rende, Italy
- Correspondence: (F.L.C.); (S.C.); Tel.: +39-0984-496204 (F.L.C.); +39-095-7338111 (S.C.); Fax: +39-0984-496203 (F.L.C.); +39-095-7338110 (S.C.)
| | - Sebastiano Cavallaro
- Institute for Research and Biomedical Innovation (IRIB), Italian National Research Council (CNR), Via Paolo Gaifami, 18, 95125 Catania, Italy; (G.M.); (G.G.); (A.G.S.); (M.G.)
- Correspondence: (F.L.C.); (S.C.); Tel.: +39-0984-496204 (F.L.C.); +39-095-7338111 (S.C.); Fax: +39-0984-496203 (F.L.C.); +39-095-7338110 (S.C.)
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12
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Valko K, Ciesla L. Amyotrophic lateral sclerosis. PROGRESS IN MEDICINAL CHEMISTRY 2019; 58:63-117. [DOI: 10.1016/bs.pmch.2018.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Jinnah H, Ulbricht RJ. Using mouse models to unlock the secrets of non-synonymous RNA editing. Methods 2018; 156:40-45. [PMID: 30827465 DOI: 10.1016/j.ymeth.2018.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/05/2018] [Accepted: 10/22/2018] [Indexed: 11/26/2022] Open
Abstract
The deamination of adenosine to inosine by RNA editing is a widespread post-transcriptional process that expands genetic diversity. Selective substitution of inosine for adenosine in pre-mRNA transcripts can alter splicing, mRNA stability, and the amino acid sequence of the encoded protein. The functional consequences of RNA editing-dependent amino acid substitution are known for only a handful of RNA editing substrates. Many of these studies began in heterologous mammalian expression systems; however, the gold-standard for determining the functional significance of transcript-specific re-coding A-to-I editing events is the generation of a mouse model that expresses only one RNA editing-dependent isoform. The frequency of site-specific RNA editing varies spatially, temporally, and in some diseases, therefore, determining the profile of RNA editing frequency is also an important element of research. Here we review the strengths and weaknesses of existing mouse models for the study of RNA editing, as well as methods for quantifying RNA editing frequencies in vivo. Importantly, we highlight opportunities for future RNA editing studies in mice, projecting that improvements in genome editing and high-throughput sequencing technologies will allow the field to excel in coming years.
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Affiliation(s)
- Hussain Jinnah
- Vanderbilt University, Department of Pharmacology, 8140 Medical Research Building 3, Nashville, TN 37240-1104, United States.
| | - Randi J Ulbricht
- Missouri State University, Department of Biomedical Sciences, 901 South National Avenue, Springfield, MO 65897, United States.
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14
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Studniarczyk D, Needham EL, Mitchison HM, Farrant M, Cull-Candy SG. Altered Cerebellar Short-Term Plasticity but No Change in Postsynaptic AMPA-Type Glutamate Receptors in a Mouse Model of Juvenile Batten Disease. eNeuro 2018; 5:ENEURO.0387-17.2018. [PMID: 29780879 PMCID: PMC5956745 DOI: 10.1523/eneuro.0387-17.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 03/22/2018] [Accepted: 03/27/2018] [Indexed: 12/28/2022] Open
Abstract
Juvenile Batten disease is the most common progressive neurodegenerative disorder of childhood. It is associated with mutations in the CLN3 gene, causing loss of function of CLN3 protein and degeneration of cerebellar and retinal neurons. It has been proposed that changes in granule cell AMPA-type glutamate receptors (AMPARs) contribute to the cerebellar dysfunction. In this study, we compared AMPAR properties and synaptic transmission in cerebellar granule cells from wild-type and Cln3 knock-out mice. In Cln3Δex1-6 cells, the amplitude of AMPA-evoked whole-cell currents was unchanged. Similarly, we found no change in the amplitude, kinetics, or rectification of synaptic currents evoked by individual quanta, or in their underlying single-channel conductance. We found no change in cerebellar expression of GluA2 or GluA4 protein. By contrast, we observed a reduced number of quantal events following mossy-fiber stimulation in Sr2+, altered short-term plasticity in conditions of reduced extracellular Ca2+, and reduced mossy fiber vesicle number. Thus, while our results suggest early presynaptic changes in the Cln3Δex1-6 mouse model of juvenile Batten disease, they reveal no evidence for altered postsynaptic AMPARs.
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Affiliation(s)
- Dorota Studniarczyk
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Elizabeth L. Needham
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Hannah M. Mitchison
- UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Mark Farrant
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Stuart G. Cull-Candy
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
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15
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Nakano M, Nakajima M. Significance of A-to-I RNA editing of transcripts modulating pharmacokinetics and pharmacodynamics. Pharmacol Ther 2018; 181:13-21. [DOI: 10.1016/j.pharmthera.2017.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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16
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Therapeutic progress in amyotrophic lateral sclerosis-beginning to learning. Eur J Med Chem 2016; 121:903-917. [DOI: 10.1016/j.ejmech.2016.06.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 04/29/2016] [Accepted: 06/10/2016] [Indexed: 12/11/2022]
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17
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Acioglu C, Mirabelli E, Baykal AT, Ni L, Ratnayake A, Heary RF, Elkabes S. Toll like receptor 9 antagonism modulates spinal cord neuronal function and survival: Direct versus astrocyte-mediated mechanisms. Brain Behav Immun 2016; 56:310-24. [PMID: 27044334 DOI: 10.1016/j.bbi.2016.03.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 03/16/2016] [Accepted: 03/31/2016] [Indexed: 12/31/2022] Open
Abstract
Toll like receptors (TLRs) are expressed by cells of the immune system and mediate the host innate immune responses to pathogens. However, increasing evidence indicates that they are important contributors to central nervous system (CNS) function in health and in pathological conditions involving sterile inflammation. In agreement with this idea, we have previously shown that intrathecal administration of a TLR9 antagonist, cytidine-phosphate-guanosine oligodeoxynucleotide 2088 (CpG ODN 2088), ameliorates the outcomes of spinal cord injury (SCI). Although these earlier studies showed a marked effect of CpG ODN 2088 on inflammatory cells, the expression of TLR9 in spinal cord (SC) neurons and astrocytes suggested that the antagonist exerts additional effects through direct actions on these cells. The current study was undertaken to assess the direct effects of CpG ODN 2088 on SC neurons, astrocytes and astrocyte-neuron interactions, in vitro. We report, for the first time, that inhibition of TLR9 in cultured SC neurons alters their function and confers protection against kainic acid (KA)-induced excitotoxic death. Moreover, the TLR9 antagonist attenuated the KA-elicited endoplasmic reticulum (ER) stress response in neurons, in vitro. CpG ODN 2088 also reduced the transcript levels and release of chemokine (C-X-C) motif ligand 1 (CXCL1) and monocyte chemotactic protein 1 (MCP-1) by astrocytes and it diminished interleukin-6 (IL-6) release without affecting transcript levels in vitro. Conditioned medium (CM) of CpG ODN 2088-treated astroglial cultures decreased the viability of SC neurons compared to CM of vehicle-treated astrocytes. However, this toxicity was not observed when astrocytes were co-cultured with neurons. Although CpG ODN 2088 limited the survival-promoting effects of astroglia, it did not reduce neuronal viability compared to controls grown in the absence of astrocytes. We conclude that the TLR9 antagonist acts directly on both SC neurons and astrocytes. Neuronal TLR9 antagonism confers protection against excitotoxic death. It is likely that this neuroprotection is partly due to the attenuation of the ER stress response provoked by excitotoxicity. Although CpG ODN 2088 limits the supportive effects of astrocytes on neurons, it could potentially exert beneficial effects by decreasing the release of pro-inflammatory cytokines and chemokines by astroglia. These findings highlight the multiple roles of TLR9 in the SC and have implications for pathological conditions including SCI where excitotoxicity and neuroinflammation play a prominent role in neuronal degeneration.
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Affiliation(s)
- Cigdem Acioglu
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States; Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Kilis 7 Aralik University, 79000 Kilis, Turkey
| | - Ersilia Mirabelli
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States; Graduate School of Biomedical Sciences, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Ahmet Tarik Baykal
- Department of Medical Biochemistry, School of Medicine, Acibadem University, 34752 Istanbul, Turkey
| | - Li Ni
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Ayomi Ratnayake
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Robert F Heary
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Stella Elkabes
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
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18
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Akamatsu M, Yamashita T, Hirose N, Teramoto S, Kwak S. The AMPA receptor antagonist perampanel robustly rescues amyotrophic lateral sclerosis (ALS) pathology in sporadic ALS model mice. Sci Rep 2016; 6:28649. [PMID: 27350567 PMCID: PMC4923865 DOI: 10.1038/srep28649] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/06/2016] [Indexed: 02/08/2023] Open
Abstract
Both TDP-43 pathology and failure of RNA editing of AMPA receptor subunit GluA2, are etiology-linked molecular abnormalities that concomitantly occur in the motor neurons of the majority of patients with amyotrophic lateral sclerosis (ALS). AR2 mice, in which an RNA editing enzyme adenosine deaminase acting on RNA 2 (ADAR2) is conditionally knocked out in the motor neurons, exhibit a progressive ALS phenotype with TDP-43 pathology in the motor neurons through a Ca2+-permeable AMPA receptor-mediated mechanism. Therefore, amelioration of the increased Ca2+ influx by AMPA receptor antagonists may be a potential ALS therapy. Here, we showed that orally administered perampanel, a selective, non-competitive AMPA receptor antagonist significantly prevented the progression of the ALS phenotype and normalized the TDP-43 pathology-associated death of motor neurons in the AR2 mice. Given that perampanel is an approved anti-epileptic drug, perampanel is a potential candidate ALS drug worthy of a clinical trial.
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Affiliation(s)
- Megumi Akamatsu
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takenari Yamashita
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Naoki Hirose
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Sayaka Teramoto
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shin Kwak
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Clinical Research Center for Medicine, International University of Health and Welfare, Ichikawa, Chiba, Japan
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19
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Joshi DC, Tewari BP, Singh M, Joshi PG, Joshi NB. AMPA receptor activation causes preferential mitochondrial Ca2+ load and oxidative stress in motor neurons. Brain Res 2015; 1616:1-9. [DOI: 10.1016/j.brainres.2015.04.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 04/18/2015] [Accepted: 04/22/2015] [Indexed: 01/05/2023]
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20
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Wu A, Wang C, Niu L. Mechanism of inhibition of the GluA1 AMPA receptor channel opening by the 2,3-benzodiazepine compound GYKI 52466 and a N-methyl-carbamoyl derivative. Biochemistry 2014; 53:3033-41. [PMID: 24738995 PMCID: PMC4025570 DOI: 10.1021/bi5002079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
2,3-Benzodiazepine derivatives, also
known as GYKI compounds, represent
a group of the most promising synthetic inhibitors of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic
acid (AMPA) receptors. Here we investigate the mechanism of inhibition
of the GluA1 channel opening and the site of inhibition by GYKI 52466
and its N-3 methyl-carbamoyl derivative, which we term as BDZ-f. GluA1 is a key AMPA receptor subunit involved in the
brain function. Excessive activity and elevated expression of GluA1,
however, has been implicated in a number of neurological disorders.
Using a laser-pulse photolysis technique, which provides ∼60
μs resolution, we measured the effect of these inhibitors on
the rate of GluA1 channel opening and the amplitude of the glutamate-induced
whole-cell current. We found that both compounds inhibit GluA1 channel
noncompetitively. Addition of an N-3 methyl-carbamoyl group to the
diazepine ring with the azomethine feature (i.e., GYKI 52466) improves
the potency of the resulting compound or BDZ-f without
changing the site of binding. This site, which we previously termed
as the “M” site on the GluA2 AMPA receptor subunit,
therefore favorably accommodates an N-3 acylating group. On the basis
of the magnitude of the inhibition constants for the same inhibitors
but different receptors, the “M” sites on GluA1 and
GuA2 are different. Overall, the “M” site or the binding
environment on GluA2 accommodates the same compounds better, or the
same inhibitors show stronger potency on GluA2, as we have reported
previously [Wang et al. Biochemistry (2011) 50, 7284−729321751782]. However, acylating
the N-3 position to occupy the N-3 side pocket of the “M”
site can significantly narrow the difference and improve the potency
of a resulting compound on GluA1.
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Affiliation(s)
- Andrew Wu
- Department of Chemistry, and Center for Neuroscience Research, University at Albany, SUNY , Albany, New York 12222, United States
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21
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Sasaki S, Hideyama T, Kwak S. Unique nuclear vacuoles in the motor neurons of conditional ADAR2-knockout mice. Brain Res 2014; 1550:36-46. [PMID: 24440630 DOI: 10.1016/j.brainres.2014.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 01/06/2014] [Accepted: 01/07/2014] [Indexed: 11/17/2022]
Abstract
A reduction in adenosine deaminase acting on RNA 2 (ADAR2) activity causes the death of spinal motor neurons specifically via the GluA2 Q/R site-RNA editing failure in sporadic amyotrophic lateral sclerosis (ALS). We studied, over time, the spinal cords of ADAR2-knockout mice, which are the mechanistic model mice for sporadic ALS, using homozygous ADAR2(flox/flox)/VAChT-Cre.Fast (AR2), homozygous ADAR2(flox/flox)/VAChT-Cre.Slow (AR2Slow), and heterozygous ADAR2(flox/+)/VAChT-Cre.Fast (AR2H) mice. The conditional ADAR2-knockout mice were divided into 3 groups by stage: presymptomatic (AR2H mice), early symptomatic (AR2 mice, AR2H mice) and late symptomatic (AR2Slow mice). Light-microscopically, some motor neurons in AR2 and AR2H mice (presymptomatic) showed simple neuronal atrophy and astrogliosis, and AR2H (early symptomatic) and AR2Slow mice often showed vacuoles predominantly in motor neurons. The number of vacuole-bearing anterior horn neurons decreased with the loss of anterior horn neurons in AR2H mice after 40 weeks of age. Electron-microscopically, in AR2 mice, while the cytoplasm of normal-looking motor neurons was almost always normal-appearing, the interior of dendrites was frequently loose and disorganized. In AR2H and AR2Slow mice, large vacuoles without a limiting membrane were observed in the anterior horns, preferentially in the nuclei of motor neurons, astrocytes and oligodendrocytes. Nuclear vacuoles were not observed in AR2res (ADAR2(flox/flox)/VAChT-Cre.Fast/GluR-B(R/R)) mice, in which motor neurons express edited GluA2 in the absence of ADAR2. These findings suggest that ADAR2-reduction is associated with progressive deterioration of nuclear architecture, resulting in vacuolated nuclei due to a Ca(2+)-permeable AMPA receptor-mediated mechanism.
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Affiliation(s)
- Shoichi Sasaki
- Department of Neurology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
| | - Takuto Hideyama
- Department of Neurology, Graduate School of Medicine, University of Tokyo, Japan
| | - Shin Kwak
- Department of Neurology, Graduate School of Medicine, University of Tokyo, Japan; Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Japan; Clinical Research Center for Medicine, International University of Health and Welfare, Japan
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22
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Bruijn LI, Cudkowicz M. Therapeutic targets for amyotrophic lateral sclerosis: current treatments and prospects for more effective therapies. Expert Rev Neurother 2014; 6:417-28. [PMID: 16533145 DOI: 10.1586/14737175.6.3.417] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although amyotrophic lateral sclerosis (ALS) was described more than 130 years ago, the cause(s) of most cases of this adult motor neuron disease remains a mystery. With the discovery of mutations in one gene (Cu/Zn superoxide dismutase) as a primary cause of some forms of ALS, model systems have been developed that have helped us begin to understand mechanisms involved in motor neuron death and enabled testing of potential new therapies. Several other genes have been implicated as risk factors in motor neuron diseases, including neurofilaments, cytoplasmic dynein and dynactin, vascular endothelial growth factor, and angiogenin. With advances in the basic research of the disease, many hypotheses accounting for motor neuron death are being explored, including loss of trophic support, protein mishandling, mitochondrial dysfunction, excitotoxicity, axonal abnormalities and inflammation. Many of these mechanisms are the focus of research in other neurodegenerative disorders, such as Parkinson's, Alzheimer's and Huntington's disease.
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23
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Wang C, Niu L. Mechanism of inhibition of the GluA2 AMPA receptor channel opening by talampanel and its enantiomer: the stereochemistry of the 4-methyl group on the diazepine ring of 2,3-benzodiazepine derivatives. ACS Chem Neurosci 2013; 4:635-44. [PMID: 23402301 DOI: 10.1021/cn3002398] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Stereoselectivity of 2,3-benzodiazepine compounds provides a unique way for the design of stereoisomers as more selective and more potent inhibitors as drug candidates for treatment of the neurological diseases involving excessive activity of AMPA receptors. Here we investigate a pair of enantiomers known as Talampanel and its (+) counterpart about their mechanism of inhibition and selectivity toward four AMPA receptor subunits or GluA1-4. We show that Talampanel is the eutomer with the endismic ratio being 14 for the closed-channel and 10 for the open-channel state of GluA2. Kinetic evidence supports that Talampanel is a noncompetitive inhibitor and it binds to the same site for those 2,3-benzodiazepine compounds with the C-4 methyl group on the diazepine ring. This site, which we term as the "M" site, recognizes preferentially those 2,3-benzodiazepine compounds with the C-4 methyl group being in the R configuration, as in the chemical structure of Talampanel. Given that Talampanel inhibits GluA1 and GluA2, but is virtually ineffective on the GluA3 and GluA4 AMPA receptor subunits, we hypothesize that the "M" site(s) on GluA1 and GluA2 to which Talampanel binds is different from that on GluA3 and GluA4. If the molecular properties of the AMPA receptors and Talampanel are used for selecting an inhibitor as a single drug candidate for controlling the activity of all AMPA receptors in vivo, Talampanel is not ideal. Our results further suggest that addition of longer acyl groups to the N-3 position should produce more potent 2,3-benzodiazepine inhibitors for the "M" site.
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Affiliation(s)
- Congzhou Wang
- Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222,
United States
| | - Li Niu
- Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222,
United States
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24
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Abstract
Manganese is an important metal for human health, being absolutely necessary for development, metabolism, and the antioxidant system. Nevertheless, excessive exposure or intake may lead to a condition known as manganism, a neurodegenerative disorder that causes dopaminergic neuronal death and parkinsonian-like symptoms. Hence, Mn has a paradoxal effect in animals, a Janus-faced metal. Extensive work has been carried out to understand Mn-induced neurotoxicity and to find an effective treatment. This review focuses on the requirement for Mn in human health as well as the diseases associated with excessive exposure to this metal.
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Affiliation(s)
- Daiana Silva Avila
- Biochemistry Graduation Program, Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul, Brazil,
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25
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Tariq A, Jantsch MF. Transcript diversification in the nervous system: a to I RNA editing in CNS function and disease development. Front Neurosci 2012; 6:99. [PMID: 22787438 PMCID: PMC3391646 DOI: 10.3389/fnins.2012.00099] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 06/14/2012] [Indexed: 12/16/2022] Open
Abstract
RNA editing by adenosine deaminases that act on RNA converts adenosines to inosines in coding and non-coding regions of mRNAs. Inosines are interpreted as guanosines and hence, this type of editing can change codons, alter splice patterns, or influence the fate of an RNA. A to I editing is most abundant in the central nervous system (CNS). Here, targets for this type of nucleotide modification frequently encode receptors and channels. In many cases, the editing-induced amino acid exchanges alter the properties of the receptors and channels. Consistently, changes in editing patterns are frequently found associated with diseases of the CNS. In this review we describe the mechanisms of RNA editing and focus on target mRNAs of editing that are functionally relevant to normal and aberrant CNS activity.
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Affiliation(s)
- Aamira Tariq
- Max F. Perutz Laboratories, Department of Chromosome Biology, University of Vienna Vienna, Austria
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26
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Wright A, Vissel B. The essential role of AMPA receptor GluR2 subunit RNA editing in the normal and diseased brain. Front Mol Neurosci 2012; 5:34. [PMID: 22514516 PMCID: PMC3324117 DOI: 10.3389/fnmol.2012.00034] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Accepted: 02/29/2012] [Indexed: 11/13/2022] Open
Abstract
α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are comprised of different combinations of GluA1–GluA4 (also known asGluR1–GluR4 and GluR-A to GluR-D) subunits. The GluA2 subunit is subject to RNA editing by the ADAR2 enzyme, which converts a codon for glutamine (Gln; Q), present in the GluA2 gene, to a codon for arginine (Arg; R) found in the mRNA. AMPA receptors are calcium (Ca2+)-permeable if they contain the unedited GluA2(Q) subunit or if they lack the GluA2 subunit. While most AMPA receptors in the brain contain the edited GluA2(R) subunit and are therefore Ca2+-impermeable, recent evidence suggests that Ca2+-permeable AMPA receptors are important in synaptic plasticity, learning, and disease. Strong evidence supports the notion that Ca2+-permeable AMPA receptors are usually GluA2-lacking AMPA receptors, with little evidence to date for a significant role of unedited GluA2 in normal brain function. However, recent detailed studies suggest that Ca2+-permeable AMPA receptors containing unedited GluA2 do in fact occur in neurons and can contribute to excitotoxic cell loss, even where it was previously thought that there was no unedited GluA2.This review provides an update on the role of GluA2 RNA editing in the healthy and diseased brain and summarizes recent insights into the mechanisms that control this process. We suggest that further studies of the role of unedited GluA2 in normal brain function and disease are warranted, and that GluA2 editing should be considered as a possible contributing factor when Ca2+-permeable AMPA receptors are observed.
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Affiliation(s)
- Amanda Wright
- Neurodegenerative Disorders Laboratory, Neuroscience Department, Garvan Institute of Medical Research, Sydney, NSW, Australia
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27
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Sica REP, Nicola AFD, González Deniselle MC, Rodriguez G, Monachelli GMG, Peralta LM, Bettini M. Sporadic amyotrophic lateral sclerosis: new hypothesis regarding its etiology and pathogenesis suggests that astrocytes might be the primary target hosting a still unknown external agent. ARQUIVOS DE NEURO-PSIQUIATRIA 2012; 69:699-706. [PMID: 21877044 DOI: 10.1590/s0004-282x2011000500023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Accepted: 04/05/2011] [Indexed: 12/11/2022]
Abstract
This article briefly describes the already known clinical features and pathogenic mechanisms underlying sporadic amyotrophic lateral sclerosis, namely excitoxicity, oxidative stress, protein damage, inflammation, genetic abnormalities and neuronal death. Thereafter, it puts forward the hypothesis that astrocytes may be the cells which serve as targets for the harmful action of a still unknown environmental agent, while neuronal death may be a secondary event following the initial insult to glial cells. The article also suggests that an emergent virus or a misfolded infectious protein might be potential candidates to accomplish this task.
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Affiliation(s)
- Roberto E P Sica
- Institute of Cardiological Investigations, Neurological Unit, School of Medicine, Buenos Aires University, Pueyrredon 1061 / piso 10, dpto. B 1118, Buenos Aires - Argentina.
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28
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Roberto E. Sporadic Amyotrophic Lateral Sclerosis: Brief Pathogenic Review and a New Causal Hypothesis. Biocybern Biomed Eng 2012. [DOI: 10.1016/s0208-5216(12)70046-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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Joshi DC, Singh M, Krishnamurthy K, Joshi PG, Joshi NB. AMPA induced Ca2+ influx in motor neurons occurs through voltage gated Ca2+ channel and Ca2+ permeable AMPA receptor. Neurochem Int 2011; 59:913-21. [PMID: 21777635 DOI: 10.1016/j.neuint.2011.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 06/27/2011] [Accepted: 06/29/2011] [Indexed: 11/19/2022]
Abstract
The rise in intracellular Ca(2+) mediated by AMPA subtype of glutamate receptors has been implicated in the pathogenesis of motor neuron disease, but the exact route of Ca(2+) entry into motor neurons is not clearly known. In the present study, we examined the role of voltage gated calcium channels (VGCCs) in AMPA induced Ca(2+) influx and subsequent intracellular signaling events responsible for motor neuron degeneration. AMPA stimulation caused sodium influx in spinal neurons that would depolarize the plasma membrane. The AMPA induced [Ca(2+)](i) rise in motor neurons as well as other spinal neurons was drastically reduced when extracellular sodium was replaced with NMDG, suggesting the involvement of voltage gated calcium channels. AMPA mediated rise in [Ca(2+)](i) was significantly inhibited by L-type VGCC blocker nifedipine, whereas ω-agatoxin-IVA and ω-conotoxin-GVIA, specific blockers of P/Q type and N-type VGCC were not effective. 1-Napthyl-acetyl spermine (NAS), an antagonist of Ca(2+) permeable AMPA receptors partially inhibited the AMPA induced [Ca(2+)](i) rise but selectively in motor neurons. Measurement of AMPA induced currents in whole cell voltage clamp mode suggests that a moderate amount of Ca(2+) influx occurs through Ca(2+) permeable AMPA receptors in a subpopulation of motor neurons. The AMPA induced mitochondrial calcium loading [Ca(2+)](m), mitochondrial depolarization and neurotoxicity were also significantly reduced in presence of nifedipine. Activation of VGCCs by depolarizing concentration of KCl (30mM) in extracellular medium increased the [Ca(2+)](i) but no change was observed in mitochondrial Ca(2+) and membrane potential. Our results demonstrate that a subpopulation of motor neurons express Ca(2+) permeable AMPA receptors, however the larger part of Ca(2+) influx occurs through L-type VGCCs subsequent to AMPA receptor activation and consequent mitochondrial dysfunction is the trigger for motor neuron degeneration. Nifedipine is an effective protective agent against AMPA induced mitochondrial stress and degeneration of motor neurons.
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Affiliation(s)
- Dinesh C Joshi
- Department of Biophysics, National Institute of Mental Health and Neuro Sciences, Bangalore 560 029, India
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Gallo A, Locatelli F. ADARs: allies or enemies? The importance of A-to-I RNA editing in human disease: from cancer to HIV-1. Biol Rev Camb Philos Soc 2011; 87:95-110. [PMID: 21682836 DOI: 10.1111/j.1469-185x.2011.00186.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosine (A) to inosine (I) in nuclear-encoded RNAs and viral RNAs. The activity of ADARs has been demonstrated to be essential in mammals and serves to fine-tune different proteins and modulate many molecular pathways. Recent findings have shown that ADAR activity is altered in many pathological tissues. Moreover, it has been shown that modulation of RNA editing is important for cell proliferation and migration, and has a protective effect on ischaemic insults. This review summarises available recent knowledge on A-to-I RNA editing and ADAR enzymes, with particular attention given to the emerging role played by these enzymes in cancer, some infectious diseases and immune-mediated disorders.
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Affiliation(s)
- Angela Gallo
- RNA Editing Laboratory, Oncohaematology Department, IRCCS, Ospedale Pediatrico "Bambino Gesù", Rome, Italy.
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Induced loss of ADAR2 engenders slow death of motor neurons from Q/R site-unedited GluR2. J Neurosci 2010; 30:11917-25. [PMID: 20826656 DOI: 10.1523/jneurosci.2021-10.2010] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
GluR2 is a subunit of the AMPA receptor, and the adenosine for the Q/R site of its pre-mRNA is converted to inosine (A-to-I conversion) by the enzyme called adenosine deaminase acting on RNA 2 (ADAR2). Failure of A-to-I conversion at this site affects multiple AMPA receptor properties, including the Ca(2+) permeability of the receptor-coupled ion channel, thereby inducing fatal epilepsy in mice (Brusa et al., 1995; Feldmeyer et al., 1999). In addition, inefficient GluR2 Q/R site editing is a disease-specific molecular dysfunction found in the motor neurons of sporadic amyotrophic lateral sclerosis (ALS) patients (Kawahara et al., 2004). Here, we generated genetically modified mice (designated as AR2) in which the ADAR2 gene was conditionally targeted in motor neurons using the Cre/loxP system. These AR2 mice showed a decline in motor function commensurate with the slow death of ADAR2-deficient motor neurons in the spinal cord and cranial motor nerve nuclei. Notably, neurons in nuclei of oculomotor nerves, which often escape degeneration in ALS, were not decreased in number despite a significant decrease in GluR2 Q/R site editing. All cellular and phenotypic changes in AR2 mice were prevented when the mice carried endogenous GluR2 alleles engineered to express edited GluR2 without ADAR2 activity (Higuchi et al., 2000). Thus, loss of ADAR2 activity causes AMPA receptor-mediated death of motor neurons.
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Rossi S, De Chiara V, Musella A, Cozzolino M, Bernardi G, Maccarrone M, Mercuri NB, Carrì MT, Centonze D. Abnormal sensitivity of cannabinoid CB1 receptors in the striatum of mice with experimental amyotrophic lateral sclerosis. ACTA ACUST UNITED AC 2010; 11:83-90. [PMID: 19452308 DOI: 10.3109/17482960902977954] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that primarily affects motor neurons. However, additional neuronal systems are also involved, and the aim of this study was to investigate the involvement of the nucleus striatum. By means of neurophysiological recordings in slices, we have investigated both excitatory and inhibitory synaptic transmission in the striatum of G93A-SOD1 ALS mice, along with the sensitivity of these synapses to cannabinoid CB1 receptor stimulation. We have observed reduced frequency of glutamate-mediated spontaneous excitatory postsynaptic currents (EPSCs) and increased frequency of GABA-mediated spontaneous inhibitory postsynaptic currents (IPSCs) recorded from striatal neurons of ALS mice, possibly due to presynaptic defects in transmitter release. The sensitivity of cannabinoid CB1 receptors controlling both glutamate and GABA transmission was remarkably potentiated in ALS mice, indicating that adaptations of the endocannabinoid system might be involved in the pathophysiology of ALS. In conclusion, our data identify possible physiological correlates of striatal dysfunction in ALS mice, and suggest that cannabinoid CB1 receptors might be potential therapeutic targets for this dramatic disease.
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Affiliation(s)
- Silvia Rossi
- Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy
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Aizawa H, Sawada J, Hideyama T, Yamashita T, Katayama T, Hasebe N, Kimura T, Yahara O, Kwak S. TDP-43 pathology in sporadic ALS occurs in motor neurons lacking the RNA editing enzyme ADAR2. Acta Neuropathol 2010; 120:75-84. [PMID: 20372915 DOI: 10.1007/s00401-010-0678-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 02/28/2010] [Accepted: 03/20/2010] [Indexed: 12/11/2022]
Abstract
Both the appearance of cytoplasmic inclusions containing phosphorylated TAR DNA-binding protein (TDP-43) and inefficient RNA editing at the GluR2 Q/R site are molecular abnormalities observed specifically in motor neurons of patients with sporadic amyotrophic lateral sclerosis (ALS). The purpose of this study is to determine whether a link exists between these two specific molecular changes in ALS spinal motor neurons. We immunohistochemically examined the expression of adenosine deaminase acting on RNA 2 (ADAR2), the enzyme that specifically catalyzes GluR2 Q/R site-editing, and the expression of phosphorylated and non-phosphorylated TDP-43 in the spinal motor neurons of patients with sporadic ALS. We found that all motor neurons were ADAR2-positive in the control cases, whereas more than half of them were ADAR2-negative in the ALS cases. All ADAR2-negative neurons had cytoplasmic inclusions that were immunoreactive to phosphorylated TDP-43, but lacked non-phosphorylated TDP-43 in the nucleus. Our results suggest a molecular link between reduced ADAR2 activity and TDP-43 pathology.
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Affiliation(s)
- Hitoshi Aizawa
- Department of Internal Medicine, Asahikawa Medical College, Japan
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The AMPA receptor as a therapeutic target: current perspectives and emerging possibilities. Future Med Chem 2010; 2:877-91. [DOI: 10.4155/fmc.10.27] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) is a subtype of the ionotropic glutamate receptors that plays a prominent role in neurotransmission and is widespread throughout the CNS. Because of this, its malfunction can result in a multitude of nervous system diseases. This review looks at compounds that are able to modulate AMPAR function by binding to one of several sites on the receptor that either downregulate its function (competitive, noncompetitive and uncompetitive antagonists) or upregulate its function (positive modulators). It will also give an account of the various diseases that have implicated AMPAR dysfunction and how specific types of AMPAR modulator may be beneficial in their treatment. The AMPAR remains an unexploited but important therapeutic target.
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Hideyama T, Yamashita T, Nishimoto Y, Suzuki T, Kwak S. Novel etiological and therapeutic strategies for neurodiseases: RNA editing enzyme abnormality in sporadic amyotrophic lateral sclerosis. J Pharmacol Sci 2010; 113:9-13. [PMID: 20424386 DOI: 10.1254/jphs.09r21fm] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
The motor neurons of patients with sporadic amyotrophic lateral sclerosis (ALS) express abundant Q/R site-unedited GluR2 mRNA, whereas those of patients with other motor neuron diseases including familial ALS associated with mutated SOD1 (ALS1) and those of normal subjects express only Q/R site-edited GluR2 mRNA. Because adenosine deaminase acting on RNA type 2 (ADAR2) specifically catalyzes GluR2 Q/R site-editing, it is likely that ADAR2 activity is not sufficient to edit this site completely in motor neurons of patients with sporadic ALS. Because these molecular abnormalities occur in disease- and motor neuron-specific fashion and induce fatal epilepsy in mice, we have hypothesized that GluR2 Q/R site-underediting due to ADAR2 underactivity is a cause of neuronal death in sporadic ALS. We found that cytoplasmic fragile X mental retardation protein interacting protein 2 (CYFIP2) mRNA had an ADAR2-mediated editing position using RNA interference knockdown. Our review will include a discussion of new ADAR2 substrates that may be useful for research on sporadic ALS.
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Affiliation(s)
- Takuto Hideyama
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Japan.
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Kwak S, Hideyama T, Yamashita T, Aizawa H. AMPA receptor-mediated neuronal death in sporadic ALS. Neuropathology 2010; 30:182-8. [DOI: 10.1111/j.1440-1789.2009.01090.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Duncan K. The role of AMPA receptor-mediated excitotoxicity in ALS: Is deficient RNA editing to blame? ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.cacc.2009.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Basavarajappa BS, Nixon RA, Arancio O. Endocannabinoid system: emerging role from neurodevelopment to neurodegeneration. Mini Rev Med Chem 2009; 9:448-62. [PMID: 19356123 DOI: 10.2174/138955709787847921] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The endocannabinoid system, including endogenous ligands ('endocannabinoids' ECs), their receptors, synthesizing and degrading enzymes, as well as transporter molecules, has been detected from the earliest stages of embryonic development and throughout pre- and postnatal development. ECs are bioactive lipids, which comprise amides, esters and ethers of long chain polyunsaturated fatty acids. Anandamide (N-arachidonoylethanolamine; AEA) and 2-arachidonoylglycerol (2-AG) are the best studied ECs, and act as agonists of cannabinoid receptors. Thus, AEA and 2-AG mimic several pharmacological effects of the exogenous cannabinoid delta9-tetrahydrocannabinol (Delta(9)-THC), the psychoactive principle of cannabis sativa preparations like hashish and marijuana. Recently, however, several lines of evidence have suggested that the EC system may play an important role in early neuronal development as well as a widespread role in neurodegeneration disorders. Many of the effects of cannabinoids and ECs are mediated by two G protein-coupled receptors (GPCRs), CB1 and CB2, although additional receptors may be implicated. Both CB1 and CB2 couple primarily to inhibitory G proteins and are subject to the same pharmacological influences as other GPCRs. This new system is briefly presented in this review, in order to put in a better perspective the role of the EC pathway from neurodevelopment to neurodegenerative disorders, like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In addition, the potential exploitation of antagonists of CB1 receptors, or of inhibitors of EC metabolism, as next-generation therapeutics is discussed.
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Affiliation(s)
- Balapal S Basavarajappa
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd, Orangeburg, NY 10962, USA.
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Mattson MP. Glutamate and neurotrophic factors in neuronal plasticity and disease. Ann N Y Acad Sci 2009; 1144:97-112. [PMID: 19076369 DOI: 10.1196/annals.1418.005] [Citation(s) in RCA: 410] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glutamate's role as a neurotransmitter at synapses has been known for 40 years, but glutamate has since been shown to regulate neurogenesis, neurite outgrowth, synaptogenesis, and neuron survival in the developing and adult mammalian nervous system. Cell-surface glutamate receptors are coupled to Ca(2+) influx and release from endoplasmic reticulum stores, which causes rapid (kinase- and protease-mediated) and delayed (transcription-dependent) responses that change the structure and function of neurons. Neurotrophic factors and glutamate interact to regulate developmental and adult neuroplasticity. For example, glutamate stimulates the production of brain-derived neurotrophic factor (BDNF), which, in turn, modifies neuronal glutamate sensitivity, Ca(2+) homeostasis, and plasticity. Neurotrophic factors may modify glutamate signaling directly, by changing the expression of glutamate receptor subunits and Ca(2+)-regulating proteins, and also indirectly by inducing the production of antioxidant enzymes, energy-regulating proteins, and antiapoptotic Bcl-2 family members. Excessive activation of glutamate receptors, under conditions of oxidative and metabolic stress, may contribute to neuronal dysfunction and degeneration in diseases ranging from stroke and Alzheimer's disease to psychiatric disorders. By enhancing neurotrophic factor signaling, environmental factors such as exercise and dietary energy restriction, and chemicals such as antidepressants may optimize glutamatergic signaling and protect against neurological disorders.
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Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA.
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Domoic acid toxicologic pathology: a review. Mar Drugs 2008; 6:180-219. [PMID: 18728725 PMCID: PMC2525487 DOI: 10.3390/md20080010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 05/16/2008] [Accepted: 05/16/2008] [Indexed: 12/29/2022] Open
Abstract
Domoic acid was identified as the toxin responsible for an outbreak of human poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels [Mytilus edulis]. The poisoning was characterized by a constellation of clinical symptoms and signs. Among the most prominent features described was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Domoic acid is produced by certain marine organisms, such as the red alga Chondria armata and planktonic diatom of the genus Pseudo-nitzschia. Since 1987, monitoring programs have been successful in preventing other human incidents of ASP. However, there are documented cases of domoic acid intoxication in wild animals and outbreaks of coastal water contamination in many regions world-wide. Hence domoic acid continues to pose a global risk to the health and safety of humans and wildlife. Several mechanisms have been implicated as mediators for the effects of domoic acid. Of particular importance is the role played by glutamate receptors as mediators of excitatory neurotransmission and the demonstration of a wide distribution of these receptors outside the central nervous system, prompting the attention to other tissues as potential target sites. The aim of this document is to provide a comprehensive review of ASP, DOM induced pathology including ultrastructural changes associated to subchronic oral exposure, and discussion of key proposed mechanisms of cell/tissue injury involved in DOM induced brain pathology and considerations relevant to food safety and human health.
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Vascular Endothelial Growth Factor Prevents Paralysis and Motoneuron Death in a Rat Model of Excitotoxic Spinal Cord Neurodegeneration. J Neuropathol Exp Neurol 2007; 66:913-22. [DOI: 10.1097/nen.0b013e3181567c16] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Du M, Ulrich H, Zhao X, Aronowski J, Jayaraman V. Water soluble RNA based antagonist of AMPA receptors. Neuropharmacology 2007; 53:242-51. [PMID: 17588619 PMCID: PMC2001231 DOI: 10.1016/j.neuropharm.2007.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 04/27/2007] [Accepted: 05/14/2007] [Indexed: 11/18/2022]
Abstract
Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are one of the important receptor classes involved in glutamate-mediated excitotoxicity. Although small molecule antagonists of this receptor have been shown to have neuroprotective properties, their low solubilities pose severe side effects in clinical trials. Here we have used the SELEX method to obtain water-soluble nuclease-resistant RNA ligands that bind to the agonist binding site of AMPA receptors. Using whole-cell current recordings, we have characterized the functional consequences of a representative aptamer from this class and show that it is a competitive antagonist of AMPA receptors and in the concentration range where it acts as an inhibitor of the AMPA receptor the RNA has no effect on the GluR6 homomeric kainate receptors. Additionally, using a fluorescence resonance energy transfer (FRET) probe, we show that this RNA ligand stabilizes the open cleft conformation of the ligand binding domain, consistent with the known structures of small antagonist-bound states of the soluble domain of this protein. Finally, using rat primary cortical neurons, we show that this RNA ligand significantly reduces neurotoxicity associated with oxygen glucose deprivation. The water-soluble and antagonistic properties of this aptamer coupled with its neuroprotective properties make it an excellent candidate for potential use in diseases or pathological conditions involving glutamate-mediated excitotoxicity.
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Affiliation(s)
- Mei Du
- 6431 Fannin, Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX 77030, USA
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Kwak S, Weiss JH. Calcium-permeable AMPA channels in neurodegenerative disease and ischemia. Curr Opin Neurobiol 2006; 16:281-7. [PMID: 16698262 DOI: 10.1016/j.conb.2006.05.004] [Citation(s) in RCA: 196] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 05/04/2006] [Indexed: 11/19/2022]
Abstract
Compelling evidence supports contributions of glutamate receptor overactivation ('excitotoxicity') to neurodegeneration in both acute conditions, such as stroke, and chronic neurodegenerative conditions, such as amyotrophic lateral sclerosis. However, anti-excitotoxic therapeutic trials, which have generally targeted highly Ca2+ permeable NMDA-type glutamate channels, have to date failed to demonstrate impressive efficacy. Whereas most AMPA type glutamate channels are Ca2+ impermeable, an evolving body of evidence supports the contention that relatively unusual Ca2+ permeable AMPA channels might be crucial contributors to injury in these conditions. These channels are preferentially expressed in discrete neuronal subpopulations, and their numbers appear to be upregulated in amyotrophic lateral sclerosis and stroke. In addition, unlike NMDA channels, Ca2+ permeable AMPA channels are not blocked by Mg2+, but are highly permeable to another potentially harmful endogenous cation, Zn2+. The targeting of these channels might provide efficacious new avenues in the therapy of certain neurological diseases.
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Affiliation(s)
- Shin Kwak
- Department of Neurology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8655 Tokyo, Japan
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Abstract
The post-transcriptional modification of mammalian transcripts by A-to-I RNA editing has been recognized as an important mechanism for the generation of molecular diversity and also regulates protein function through recoding of genomic information. As the molecular players of editing are characterized and an increasing number of genes become identified that are subject to A-to-I modification, the potential impact of editing on the etiology or progression of human diseases is realized. Here we review the recent knowledge on where disturbances in A-to-I RNA editing have been correlated with human disease phenotypes.
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