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Wang C, Gao MQ. Research Progress on the Antidepressant Effects of Baicalin and Its Aglycone Baicalein: A Systematic Review of the Biological Mechanisms. Neurochem Res 2024; 49:14-28. [PMID: 37715823 DOI: 10.1007/s11064-023-04026-3] [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: 05/27/2023] [Revised: 08/16/2023] [Accepted: 08/31/2023] [Indexed: 09/18/2023]
Abstract
Depression is the most prevalent mental disorder, affecting more than 300 million adults worldwide each year, which can lead to serious economic and social problems. Antidepressants are usually the first-line treatment for depression, however, traditional antidepressants on the market have the disadvantage of low remission rates and may cause side effects to patients, therefore, the current focus in the field of depression is to develop novel therapeutic agents with high remission rates and few side effects. In this context, the antidepressant effects of natural compounds have received attention. Baicalin (baicalein-7-O-glucuronide) and its aglycone baicalein (5,6,7-trihydroxyflavone) are flavonoid compounds extracted from the root of Scutellaria baicalensis. Although lacking the support of clinical data, they have been shown to have significantly promising antidepressant activity in many preclinical studies through various rodent models of depression. This paper reviews the antidepressant effects of baicalin and baicalein in experimental animal models, with emphasis on summarizing the molecular mechanisms of their antidepressant effects including regulation of the HPA axis, inhibition of inflammation and oxidative stress, reduction of neuronal apoptosis and promotion of neurogenesis, as well as amelioration of mitochondrial dysfunction. Controlled clinical trials should be conducted in the future to examine the effects of baicalin and baicalein on depression in humans.
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Affiliation(s)
- Chen Wang
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, China
| | - Ming-Qi Gao
- Department of Clinical Pharmacology, School of Pharmacy, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, China.
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Chu E, Mychasiuk R, Green TRF, Zamani A, Dill LK, Sharma R, Raftery AL, Tsantikos E, Hibbs ML, Semple BD. Regulation of microglial responses after pediatric traumatic brain injury: exploring the role of SHIP-1. Front Neurosci 2023; 17:1276495. [PMID: 37901420 PMCID: PMC10603304 DOI: 10.3389/fnins.2023.1276495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 09/18/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction Severe traumatic brain injury (TBI) is the world's leading cause of permanent neurological disability in children. TBI-induced neurological deficits may be driven by neuroinflammation post-injury. Abnormal activity of SH2 domain-containing inositol 5' phosphatase-1 (SHIP-1) has been associated with dysregulated immunological responses, but the role of SHIP-1 in the brain remains unclear. The current study investigated the immunoregulatory role of SHIP-1 in a mouse model of moderate-severe pediatric TBI. Methods SHIP-1+/- and SHIP-1-/- mice underwent experimental TBI or sham surgery at post-natal day 21. Brain gene expression was examined across a time course, and immunofluorescence staining was evaluated to determine cellular immune responses, alongside peripheral serum cytokine levels by immunoassays. Brain tissue volume loss was measured using volumetric analysis, and behavior changes both acutely and chronically post-injury. Results Acutely, inflammatory gene expression was elevated in the injured cortex alongside increased IBA-1 expression and altered microglial morphology; but to a similar extent in SHIP-1-/- mice and littermate SHIP-1+/- control mice. Similarly, the infiltration and activation of CD68-positive macrophages, and reactivity of GFAP-positive astrocytes, was increased after TBI but comparable between genotypes. TBI increased anxiety-like behavior acutely, whereas SHIP-1 deficiency alone reduced general locomotor activity. Chronically, at 12-weeks post-TBI, SHIP-1-/- mice exhibited reduced body weight and increased circulating cytokines. Pro-inflammatory gene expression in the injured hippocampus was also elevated in SHIP-1-/- mice; however, GFAP immunoreactivity at the injury site in TBI mice was lower. TBI induced a comparable loss of cortical and hippocampal tissue in both genotypes, while SHIP-1-/- mice showed reduced general activity and impaired working memory, independent of TBI. Conclusion Together, evidence does not support SHIP-1 as an essential regulator of brain microglial morphology, brain immune responses, or the extent of tissue damage after moderate-severe pediatric TBI in mice. However, our data suggest that reduced SHIP-1 activity induces a greater inflammatory response in the hippocampus chronically post-TBI, warranting further investigation.
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Affiliation(s)
- Erskine Chu
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Deparment of Neurology, Alfred Health, Prahran, VIC, Australia
| | - Tabitha R. F. Green
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, United States
| | - Akram Zamani
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - Larissa K. Dill
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Alfred Health, Prahran, VIC, Australia
| | - Rishabh Sharma
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - April L. Raftery
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Evelyn Tsantikos
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Margaret L. Hibbs
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Bridgette D. Semple
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Deparment of Neurology, Alfred Health, Prahran, VIC, Australia
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia
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Neves D, Salazar IL, Almeida RD, Silva RM. Molecular mechanisms of ischemia and glutamate excitotoxicity. Life Sci 2023; 328:121814. [PMID: 37236602 DOI: 10.1016/j.lfs.2023.121814] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/05/2023] [Accepted: 05/23/2023] [Indexed: 05/28/2023]
Abstract
Excitotoxicity is classically defined as the neuronal damage caused by the excessive release of glutamate, and subsequent activation of excitatory plasma membrane receptors. In the mammalian brain, this phenomenon is mainly driven by excessive activation of glutamate receptors (GRs). Excitotoxicity is common to several chronic disorders of the Central Nervous System (CNS) and is considered the primary mechanism of neuronal loss of function and cell death in acute CNS diseases (e.g. ischemic stroke). Multiple mechanisms and pathways lead to excitotoxic cell damage including pro-death signaling cascade events downstream of glutamate receptors, calcium (Ca2+) overload, oxidative stress, mitochondrial impairment, excessive glutamate in the synaptic cleft as well as altered energy metabolism. Here, we review the current knowledge on the molecular mechanisms that underlie excitotoxicity, emphasizing the role of Nicotinamide Adenine Dinucleotide (NAD) metabolism. We also discuss novel and promising therapeutic strategies to treat excitotoxicity, highlighting recent clinical trials. Finally, we will shed light on the ongoing search for stroke biomarkers, an exciting and promising field of research, which may improve stroke diagnosis, prognosis and allow better treatment options.
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Affiliation(s)
- Diogo Neves
- iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Ivan L Salazar
- Multidisciplinary Institute of Ageing, MIA - Portugal, University of Coimbra, Coimbra, Portugal
| | - Ramiro D Almeida
- iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal; CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
| | - Raquel M Silva
- iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal; Universidade Católica Portuguesa, Faculdade de Medicina Dentária, Centro de Investigação Interdisciplinar em Saúde, Viseu, Portugal.
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Gaidin SG, Maiorov SA, Laryushkin DP, Zinchenko VP, Kosenkov AM. A novel approach for vital visualization and studying of neurons containing Ca 2+ -permeable AMPA receptors. J Neurochem 2023; 164:583-597. [PMID: 36415923 DOI: 10.1111/jnc.15729] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 10/19/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022]
Abstract
Calcium-permeable AMPA receptors (CP-AMPARs) play a pivotal role in brain functioning in health and disease. They are involved in synaptic plasticity, synaptogenesis, and neuronal circuits development. However, the functions of neurons expressing CP-AMPARs and their role in the modulation of network activity remain elusive since reliable and accurate visualization methods are absent. Here we developed an approach allowing the vital identification of neurons containing CP-AMPARs. The proposed method relies on evaluating Ca2+ influx in neurons during activation of AMPARs in the presence of NMDAR and KAR antagonists, and blockers of voltage-gated Ca2+ channels. Using this method, we studied the properties of CP-AMPARs-containing neurons. We showed that the overwhelming majority of neurons containing CP-AMPARs are GABAergic, and they are distinguished by higher amplitudes of the calcium responses to applications of the agonists. Furthermore, about 30% of CP-AMPARs-containing neurons demonstrate the presence of GluK1-containing KARs. Although CP-AMPARs-containing neurons are characterized by more significant Ca2+ influx during the activation of AMPARs than other neurons, AMPAR-mediated Na+ influx is similar in these two groups. We revealed that neurons containing CP-AMPARs demonstrate weak GABA(A)R-mediated inhibition because of the low percentage of GABAergic synapses on the soma of these cells. However, our data show that weak GABA(A)R-mediated inhibition is inherent to all GABAergic neurons in the culture and cannot be considered a unique feature of CP-AMPARs-containing neurons. We believe that the suggested approach will help to understand the role of CP-AMPARs in the mammalian nervous system in more detail.
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Affiliation(s)
- Sergei G Gaidin
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Sergei A Maiorov
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Denis P Laryushkin
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Valery P Zinchenko
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Artem M Kosenkov
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
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Niida-Kawaguchi M, Kakita A, Noguchi N, Kazama M, Masui K, Kato Y, Yamamoto T, Sawada T, Kitagawa K, Watabe K, Shibata N. Soluble iron accumulation induces microglial glutamate release in the spinal cord of sporadic amyotrophic lateral sclerosis. Neuropathology 2019; 40:152-166. [PMID: 31883180 DOI: 10.1111/neup.12632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 12/14/2022]
Abstract
Previous studies on sporadic amyotrophic lateral sclerosis (SALS) demonstrated iron accumulation in the spinal cord and increased glutamate concentration in the cerebrospinal fluid. To clarify the relationship between the two phenomena, we first performed quantitative and morphological analyses of substances related to iron and glutamate metabolism using spinal cords obtained at autopsy from 12 SALS patients and 12 age-matched control subjects. Soluble iron content determined by the Ferrozine method as well as ferritin (Ft) and glutaminase C (GLS-C) expression levels on Western blots were significantly higher in the SALS group than in the control group, while ferroportin (FPN) levels on Western blots were significantly reduced in the SALS group as compared to the control group. There was no significant difference in aconitase 1 (ACO1) and tumor necrosis factor-alpha (TNFα)-converting enzyme (TACE) levels on Western blots between the two groups. Immunohistochemically, Ft, ACO1, TACE, TNFα, and GLS-C were proven to be selectively expressed in microglia. Immunoreactivities for FPN and hepcidin were localized in neuronal and glial cells. Based on these observations, it is predicted that soluble iron may stimulate microglial glutamate release. To address this issue, cell culture experiments were carried out on a microglial cell line (BV-2). Treatment of BV-2 cells with ferric ammonium citrate (FAC) brought about significant increases in intracellular soluble iron and Ft expression levels and conditioned medium glutamate and TNFα concentrations. Glutamate concentration was also significantly increased in conditioned media of TNFα-treated BV-2 cells. While the FAC-driven increases in glutamate and TNFα release were completely canceled by pretreatment with ACO1 and TACE inhibitors, respectively, the TNFα-driven increase in glutamate release was completely canceled by GLS-C inhibitor pretreatment. Moreover, treatment of BV-2 cells with hepcidin resulted in a significant reduction in FPN expression levels on Western blots of the intracellular total protein extracts. The present results provide in vivo and in vitro evidence that microglial glutamate release in SALS spinal cords is enhanced by intracellular soluble iron accumulation-induced activation of ACO1 and TACE and by increased extracellular TNFα-stimulated GLS-C upregulation, and suggest a positive feedback mechanism to maintain increased intracellular soluble iron levels, involving TNFα, hepcidin, and FPN.
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Affiliation(s)
- Motoko Niida-Kawaguchi
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Noriko Noguchi
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Miku Kazama
- Faculty of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Kenta Masui
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Yoichiro Kato
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Tomoko Yamamoto
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Tatsuo Sawada
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazuo Kitagawa
- Department of Neurology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazuhiko Watabe
- Department of Medical Technology, Faculty of Health Sciences, Kyorin University, Mitaka, Japan
| | - Noriyuki Shibata
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
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Wang C, Wei Y, Yuan Y, Yu Y, Xie K, Dong B, Shi Y, Wang G. The role of PI3K-mediated AMPA receptor changes in post-conditioning of propofol in brain protection. BMC Neurosci 2019; 20:51. [PMID: 31570094 PMCID: PMC6771103 DOI: 10.1186/s12868-019-0532-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 09/13/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND We aimed to study the role of amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) glutamate receptor 2 (GluR2) subunit trafficking, and activity changes in short-term neuroprotection provided by propofol post-conditioning. We also aimed to determine the role of phosphoinositide-3-kinase (PI3K) in the regulation of these processes. METHODS Rats underwent 1 h of focal cerebral ischemia followed by 23 h of reperfusion were randomly divided into 6 groups (n = 36 per group): sham- operation (S), ischemia-reperfusion (IR), propofol (P group, propofol 20 mg/kg/h at the onset of reperfusion for 2 h after 60 min of occlusion), and LY294002 (PI3K non-selective antagonist) + sham (L + S, LY294002 of 1.5 mg/kg was infused 30 min before sham operation), LY294002+ ischemia-reperfusion (L + IR, LY294002 of 1.5 mg/kg was infused 30 min before middle cerebral artery occlusion), LY294002 + IR + propofol (L + P, LY294002 of 1.5 mg/kg was infused 30 min before middle cerebral artery occlusion and propofol 20 mg/kg/h at the onset of reperfusion for 2 h after 60 min of occlusion). RESULTS Compared with group IR, rats in group P had significant lower neurologic defect scores and infarct volume. Additionally, consistent with enhanced expression of PI3K-AMPAR GluR2 subunit complex substances in ipsilateral hippocampus, GluR2 subunits showed increased levels in both the plasma and postsynaptic membranes of neurons, while pGluR2 expression was reduced in group P. Furthermore, LY294002, the PI3K non-selective antagonist, blocked those effects. CONCLUSION These observations demonstrated that propofol post-conditioning revealed acute neuroprotective role against transient MCAO in rats. The short-term neuroprotective effect was contributed by enhanced GluR2 subunits trafficking to membrane and postsynaptic membranes of neurons, as well as down-regulated the expression of pGluR2 in damaged hippocampus. Finally, the above-mentioned protective mechanism might be contributed by increased combination of PI3K to AMPAR GluR2 subunit, thus maintained the expression and activation of AMPAR GluR2 in the ipsilateral hippocampus.
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Affiliation(s)
- Chenxu Wang
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
| | - Ying Wei
- Department of Anesthesiology, Tianjin People’s Hospital, Tianjin Union Medical Center, Tianjin, 300191 China
| | - Yuan Yuan
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
| | - Yonghao Yu
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
| | - Keliang Xie
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
| | - Beibei Dong
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
| | - Yuan Shi
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
| | - Guolin Wang
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, General Hospital of Tianjin Medical University, No. 154 Anshan Road, Heping District, Tianjin, 300052 People’s Republic of China
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Gurung S, Evans AJ, Wilkinson KA, Henley JM. ADAR2-mediated Q/R editing of GluK2 regulates kainate receptor upscaling in response to suppression of synaptic activity. J Cell Sci 2018; 131:jcs222273. [PMID: 30559217 PMCID: PMC6307878 DOI: 10.1242/jcs.222273] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 11/19/2018] [Indexed: 12/29/2022] Open
Abstract
Kainate receptors (KARs) regulate neuronal excitability and network function. Most KARs contain the subunit GluK2 (also known as GRIK2), and the properties of these receptors are determined in part by ADAR2 (also known as ADARB1)-mediated mRNA editing of GluK2, which changes a genomically encoded glutamine residue into an arginine residue (Q/R editing). Suppression of synaptic activity reduces ADAR2-dependent Q/R editing of GluK2 with a consequential increase in GluK2-containing KAR surface expression. However, the mechanism underlying this reduction in GluK2 editing has not been addressed. Here, we show that induction of KAR upscaling, a phenomenon in which surface expression of receptors is increased in response to a chronic decrease in synaptic activity, results in proteasomal degradation of ADAR2, which reduces GluK2 Q/R editing. Because KARs incorporating unedited GluK2(Q) assemble and exit the ER more efficiently, this leads to an upscaling of KAR surface expression. Consistent with this, we demonstrate that partial ADAR2 knockdown phenocopies and occludes KAR upscaling. Moreover, we show that although the AMPA receptor (AMPAR) subunit GluA2 (also known as GRIA2) also undergoes ADAR2-dependent Q/R editing, this process does not mediate AMPAR upscaling. These data demonstrate that activity-dependent regulation of ADAR2 proteostasis and GluK2 Q/R editing are key determinants of KAR, but not AMPAR, trafficking and upscaling.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sonam Gurung
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Ashley J Evans
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Kevin A Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Jeremy M Henley
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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Sharma A, Kaur G. Tinospora cordifolia as a potential neuroregenerative candidate against glutamate induced excitotoxicity: an in vitro perspective. Altern Ther Health Med 2018; 18:268. [PMID: 30285727 PMCID: PMC6167833 DOI: 10.1186/s12906-018-2330-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/20/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Glutamate, the major excitatory neurotransmitter of CNS acts as a neurotoxin at higher concentrations. Prolonged activation of glutamate receptors results in progressive neuronal damage by aggravating calcium influx, inducing mitochondrial damage and oxidative stress. Excitotoxic cell death is associated with the pathogenesis of various neurodegenerative disorders such as trauma, brain injury and neurodegenerative diseases. The current study was designed to investigate the neuroprotective and neuroregenerative potential of Tinospora cordifolia against glutamate-induced excitotoxicity using primary cerebellar neuronal cultures as a model system. METHODS Monosodium salt of glutamate was used to induce neurotoxic injury in primary cerebellar neurons. Four extracts including Hexane extract, Chloroform extract, Ethyl acetate, and Butanol extract were obtained from fractionation of previously reported aqueous ethanolic extract of T. cordifolia and tested for neuroprotective activity. Out of the four fractions, Butanol extract of T. cordifolia (B-TCE) exhibited neuroprotective potential by preventing degeneration of neurons induced by glutamate. Expression of different neuronal, apoptotic, inflammatory, cell cycle regulatory and plasticity markers was studied by immunostaining and Western blotting. Neurite outgrowth and migration were also studied using primary explant cultures, wound scratch and gelatin zymogram assay. RESULTS At molecular level, B-TCE pretreatment of glutamate-treated cultures normalized the stress-induced downregulation in the expression of neuronal markers (MAP-2, GAP-43, NF200) and anti-apoptotic marker (Bcl-xL). Further, cells exposed to glutamate showed enhanced expression of inflammatory (NF-κB, AP-1) and senescence markers (HSP70, Mortalin) as well as the extent of mitochondrial damage. However, B-TCE pretreatment prevented this increase and inhibited glutamate-induced onset of inflammation, stress and mitochondrial membrane damage. Furthermore, B-TCE was observed to promote regeneration, migration and plasticity of cerebellar neurons, which was otherwise significantly inhibited by glutamate treatment. CONCLUSION These results suggest that B-TCE may have neuroprotective and neuroregenerative potential against catastrophic consequences of glutamate-mediated excitotoxicity and could be a potential therapeutic candidate for neurodegenerative diseases.
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Starr A, Sattler R. Synaptic dysfunction and altered excitability in C9ORF72 ALS/FTD. Brain Res 2018; 1693:98-108. [PMID: 29453960 DOI: 10.1016/j.brainres.2018.02.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/06/2018] [Accepted: 02/10/2018] [Indexed: 02/08/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is characterized by a progressive degeneration of upper and lower motor neurons, resulting in fatal paralysis due to denervation of the muscle. Due to genetic, pathological and symptomatic overlap, ALS is now considered a spectrum disease together with frontotemporal dementia (FTD), the second most common cause of dementia in individuals under the age of 65. Interestingly, in both diseases, there is a large prevalence of RNA binding proteins (RBPs) that are mutated and considered disease-causing, or whose dysfunction contribute to disease pathogenesis. The most common shared genetic mutation in ALS/FTD is a hexanucleuotide repeat expansion within intron 1 of C9ORF72 (C9). Three potentially overlapping, putative toxic mechanisms have been proposed: loss of function due to haploinsufficient expression of the C9ORF72 mRNA, gain of function of the repeat RNA aggregates, or RNA foci, and repeat-associated non-ATG-initiated translation (RAN) of the repeat RNA into toxic dipeptide repeats (DPRs). Regardless of the causative mechanism, disease symptoms are ultimately caused by a failure of neurotransmission in three regions: the brain, the spinal cord, and the neuromuscular junction. Here, we review C9 ALS/FTD-associated synaptic dysfunction and aberrant neuronal excitability in these three key regions, focusing on changes in morphology and synapse formation, excitability, and excitotoxicity in patients, animal models, and in vitro models. We compare these deficits to those seen in other forms of ALS and FTD in search of shared pathways, and discuss the potential targeting of synaptic dysfunctions for therapeutic intervention in ALS and FTD patients.
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Affiliation(s)
- Alexander Starr
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, United States
| | - Rita Sattler
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, United States.
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Mokrushin AA. Modification of glutamatergic mechanisms in the model of posttraumatic stress disorder. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 118:48-52. [DOI: 10.17116/jnevro201811810148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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11
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Gallo A, Vukic D, Michalík D, O’Connell MA, Keegan LP. ADAR RNA editing in human disease; more to it than meets the I. Hum Genet 2017; 136:1265-1278. [DOI: 10.1007/s00439-017-1837-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/22/2017] [Indexed: 01/08/2023]
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12
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Bailey JM, Colón-Rodríguez A, Atchison WD. Evaluating a Gene-Environment Interaction in Amyotrophic Lateral Sclerosis: Methylmercury Exposure and Mutated SOD1. Curr Environ Health Rep 2017; 4:200-207. [PMID: 28397096 PMCID: PMC5494256 DOI: 10.1007/s40572-017-0144-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Gene-environment (GxE) interactions likely contribute to numerous diseases, but are often difficult to model in the laboratory. Such interactions have been widely hypothesized for amyotrophic lateral sclerosis (ALS); recent controlled laboratory studies are discussed here and hypotheses related to possible mechanisms of action are offered. Using methylmercury exposure and mutated SOD1 to model the impacts of such an interaction, we interpret evidence about their respective mechanisms of toxicity to interrogate the possibility of additive (or synergistic) effects when combined. RECENT FINDINGS Recent work has converged on mechanisms of calcium-mediated glutamate excitotoxicity as a likely contributor in one model of a gene-environment interaction affecting the onset and progression of ALS-like phenotype. The current experimental literature on mechanisms of metal-induced neuronal injury and their relevant interactions with genetic contributions in ALS is sparse, but we describe those studies here and offer several integrative hypotheses about the likely mechanisms involved.
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Affiliation(s)
- Jordan M Bailey
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA
| | - Alexandra Colón-Rodríguez
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA
- Comparative Medicine and Integrative Biology Program, Michigan State University, East Lansing, MI, 48824-1317, USA
| | - William D Atchison
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA.
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA.
- Comparative Medicine and Integrative Biology Program, Michigan State University, East Lansing, MI, 48824-1317, USA.
- , Life Science Building, 1355 Bogue St. Room B331A, East Lansing, MI, 48824-1317, USA.
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13
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Abstract
Inosine is one of the most common modifications found in human RNAs and the Adenosine Deaminases that act on RNA (ADARs) are the main enzymes responsible for its production. ADARs were first discovered in the 1980s and since then our understanding of ADARs has advanced tremendously. For instance, it is now known that defective ADAR function can cause human diseases. Furthermore, recently solved crystal structures of the human ADAR2 deaminase bound to RNA have provided insights regarding the catalytic and substrate recognition mechanisms. In this chapter, we describe the occurrence of inosine in human RNAs and the newest perspective on the ADAR family of enzymes, including their substrate recognition, catalytic mechanism, regulation as well as the consequences of A-to-I editing, and their relation to human diseases.
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14
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Descalzi G, Mitsi V, Purushothaman I, Gaspari S, Avrampou K, Loh YHE, Shen L, Zachariou V. Neuropathic pain promotes adaptive changes in gene expression in brain networks involved in stress and depression. Sci Signal 2017; 10:10/471/eaaj1549. [PMID: 28325815 DOI: 10.1126/scisignal.aaj1549] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neuropathic pain is a complex chronic condition characterized by various sensory, cognitive, and affective symptoms. A large percentage of patients with neuropathic pain are also afflicted with depression and anxiety disorders, a pattern that is also seen in animal models. Furthermore, clinical and preclinical studies indicate that chronic pain corresponds with adaptations in several brain networks involved in mood, motivation, and reward. Chronic stress is also a major risk factor for depression. We investigated whether chronic pain and stress affect similar molecular mechanisms and whether chronic pain can affect gene expression patterns that are involved in depression. Using two mouse models of neuropathic pain and depression [spared nerve injury (SNI) and chronic unpredictable stress (CUS)], we performed next-generation RNA sequencing and pathway analysis to monitor changes in gene expression in the nucleus accumbens (NAc), the medial prefrontal cortex (mPFC), and the periaqueductal gray (PAG). In addition to finding unique transcriptome profiles across these regions, we identified a substantial number of signaling pathway-associated genes with similar changes in expression in both SNI and CUS mice. Many of these genes have been implicated in depression, anxiety, and chronic pain in patients. Our study provides a resource of the changes in gene expression induced by long-term neuropathic pain in three distinct brain regions and reveals molecular connections between pain and chronic stress.
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Affiliation(s)
- Giannina Descalzi
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Vasiliki Mitsi
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Immanuel Purushothaman
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sevasti Gaspari
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kleopatra Avrampou
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yong-Hwee Eddie Loh
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Li Shen
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Venetia Zachariou
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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15
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EAAT2 and the Molecular Signature of Amyotrophic Lateral Sclerosis. ADVANCES IN NEUROBIOLOGY 2017; 16:117-136. [PMID: 28828608 DOI: 10.1007/978-3-319-55769-4_6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapid and fatal neurodegenerative disease, primarily affecting upper and lower motor neurons. It is an extremely heterogeneous disease in both cause and symptom development, and its mechanisms of pathogenesis remain largely unknown. Excitotoxicity, a process caused by excessive glutamate signaling, is believed to play a substantial role, however. Excessive glutamate release, changes in postsynaptic glutamate receptors, and reduction of functional astrocytic glutamate transporters contribute to excitotoxicity in ALS. Here, we explore the roles of each, with a particular emphasis on glutamate transporters and attempts to increase them as therapy for ALS. Screening strategies have been employed to find compounds that increase the functional excitatory amino acid transporter EAAT2 (GLT1), which is responsible for the vast majority of glutamate clearance. One such compound, ceftriaxone, was recently tested in clinical trials but unfortunately did not modify disease course, though its effect on EAAT2 expression in patients was not measured.
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16
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Functions of the RNA Editing Enzyme ADAR1 and Their Relevance to Human Diseases. Genes (Basel) 2016; 7:genes7120129. [PMID: 27999332 PMCID: PMC5192505 DOI: 10.3390/genes7120129] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/07/2016] [Accepted: 12/12/2016] [Indexed: 12/17/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) convert adenosine to inosine in double-stranded RNA (dsRNA). Among the three types of mammalian ADARs, ADAR1 has long been recognized as an essential enzyme for normal development. The interferon-inducible ADAR1p150 is involved in immune responses to both exogenous and endogenous triggers, whereas the functions of the constitutively expressed ADAR1p110 are variable. Recent findings that ADAR1 is involved in the recognition of self versus non-self dsRNA provide potential explanations for its links to hematopoiesis, type I interferonopathies, and viral infections. Editing in both coding and noncoding sequences results in diseases ranging from cancers to neurological abnormalities. Furthermore, editing of noncoding sequences, like microRNAs, can regulate protein expression, while editing of Alu sequences can affect translational efficiency and editing of proximal sequences. Novel identifications of long noncoding RNA and retrotransposons as editing targets further expand the effects of A-to-I editing. Besides editing, ADAR1 also interacts with other dsRNA-binding proteins in editing-independent manners. Elucidating the disease-specific patterns of editing and/or ADAR1 expression may be useful in making diagnoses and prognoses. In this review, we relate the mechanisms of ADAR1′s actions to its pathological implications, and suggest possible mechanisms for the unexplained associations between ADAR1 and human diseases.
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17
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Curcio M, Salazar IL, Mele M, Canzoniero LMT, Duarte CB. Calpains and neuronal damage in the ischemic brain: The swiss knife in synaptic injury. Prog Neurobiol 2016; 143:1-35. [PMID: 27283248 DOI: 10.1016/j.pneurobio.2016.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022]
Abstract
The excessive extracellular accumulation of glutamate in the ischemic brain leads to an overactivation of glutamate receptors with consequent excitotoxic neuronal death. Neuronal demise is largely due to a sustained activation of NMDA receptors for glutamate, with a consequent increase in the intracellular Ca(2+) concentration and activation of calcium- dependent mechanisms. Calpains are a group of Ca(2+)-dependent proteases that truncate specific proteins, and some of the cleavage products remain in the cell, although with a distinct function. Numerous studies have shown pre- and post-synaptic effects of calpains on glutamatergic and GABAergic synapses, targeting membrane- associated proteins as well as intracellular proteins. The resulting changes in the presynaptic proteome alter neurotransmitter release, while the cleavage of postsynaptic proteins affects directly or indirectly the activity of neurotransmitter receptors and downstream mechanisms. These alterations also disturb the balance between excitatory and inhibitory neurotransmission in the brain, with an impact in neuronal demise. In this review we discuss the evidence pointing to a role for calpains in the dysregulation of excitatory and inhibitory synapses in brain ischemia, at the pre- and post-synaptic levels, as well as the functional consequences. Although targeting calpain-dependent mechanisms may constitute a good therapeutic approach for stroke, specific strategies should be developed to avoid non-specific effects given the important regulatory role played by these proteases under normal physiological conditions.
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Affiliation(s)
- Michele Curcio
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ivan L Salazar
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Miranda Mele
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
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18
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Bonini D, Filippini A, La Via L, Fiorentini C, Fumagalli F, Colombi M, Barbon A. Chronic glutamate treatment selectively modulates AMPA RNA editing and ADAR expression and activity in primary cortical neurons. RNA Biol 2015; 12:43-53. [PMID: 25625181 DOI: 10.1080/15476286.2015.1008365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Adenosine-to-inosine RNA editing is a post-transcriptional process, catalyzed by ADAR enzymes, with an important role in diversifying the number of proteins derived from a single gene. In neurons, editing of ionotropic AMPA glutamate receptors has been shown to be altered under several experimental conditions, including severe pathologies, thus highlighting the potential significance of its modulation. In this study, we treated rat primary cortical cell cultures with a sub-lethal dose of glutamate (10 μM), focusing on RNA editing and ADAR activity. We found that chronic glutamate treatment down-regulates RNA editing levels at the R/G site of GluA2-4 subunits of AMPA receptors and at the K/E site of CYFIP2. These changes are site-specific since they were not observed either for the GluA2 Q/R site or for other non-glutamatergic sites. Glutamate treatment also down-regulates the protein expression levels of both ADAR1 and ADAR2 enzymes, through a pathway that is Ca(2+)- and calpain-dependent. Given that AMPA receptors containing unedited subunits show a slower recovery rate from desensitization compared to those containing edited forms, the reduced editing at the R/G site may, at least in part, compensate for glutamate over-stimulation, perhaps through the reduced activation of postsynaptic receptors. In summary, our data provide direct evidence of the involvement of ADAR1 and ADAR2 activity as a possible compensatory mechanism for neuronal protection following glutamate over-stimulation.
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Affiliation(s)
- Daniela Bonini
- a Biology and Genetic Division; Department of Molecular and Translational Medicine; National Institute of Neuroscience; University of Brescia ; Brescia , Italy
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19
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Romano G, Appocher C, Scorzeto M, Klima R, Baralle FE, Megighian A, Feiguin F. Glial TDP-43 regulates axon wrapping, GluRIIA clustering and fly motility by autonomous and non-autonomous mechanisms. Hum Mol Genet 2015; 24:6134-45. [PMID: 26276811 PMCID: PMC4599672 DOI: 10.1093/hmg/ddv330] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/07/2015] [Indexed: 12/12/2022] Open
Abstract
Alterations in the glial function of TDP-43 are becoming increasingly associated with the neurological symptoms observed in Amyotrophic Lateral Sclerosis (ALS), however, the physiological role of this protein in the glia or the mechanisms that may lead to neurodegeneration are unknown. To address these issues, we modulated the expression levels of TDP-43 in the Drosophila glia and found that the protein was required to regulate the subcellular wrapping of motoneuron axons, promote synaptic growth and the formation of glutamate receptor clusters at the neuromuscular junctions. Interestingly, we determined that the glutamate transporter EAAT1 mediated the regulatory functions of TDP-43 in the glia and demonstrated that genetic or pharmacological compensations of EAAT1 activity were sufficient to modulate glutamate receptor clustering and locomotive behaviors in flies. The data uncovers autonomous and non-autonomous functions of TDP-43 in the glia and suggests new experimentally based therapeutic strategies in ALS.
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Affiliation(s)
- Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste 34149, Italy and
| | - Chiara Appocher
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste 34149, Italy and
| | - Michele Scorzeto
- Department of Biomedical Sciences, University of Padova, via Marzolo 3, Padova 35131, Italy
| | - Raffaella Klima
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste 34149, Italy and
| | - Francisco E Baralle
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste 34149, Italy and
| | - Aram Megighian
- Department of Biomedical Sciences, University of Padova, via Marzolo 3, Padova 35131, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste 34149, Italy and
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20
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Abstract
Adenosine-to-inosine (A-to-I) RNA editing, the most prevalent mode of transcript modification in higher eukaryotes, is catalysed by the adenosine deaminases acting on RNA (ADARs). A-to-I editing imposes an additional layer of gene regulation as it dictates various aspects of RNA metabolism, including RNA folding, processing, localization and degradation. Furthermore, editing events in exonic regions contribute to proteome diversity as translational machinery decodes inosine as guanosine. Although it has been demonstrated that dysregulated A-to-I editing contributes to various diseases, the precise regulatory mechanisms governing this critical cellular process have yet to be fully elucidated. However, integration of previous studies revealed that regulation of A-to-I editing is multifaceted, weaving an intricate network of auto- and transregulations, including the involvement of virus-originated factors like adenovirus-associated RNA. Taken together, it is apparent that tipping of any regulatory components will have profound effects on A-to-I editing, which in turn contributes to both normal and aberrant physiological conditions. A complete understanding of this intricate regulatory network may ultimately be translated into new therapeutic strategies against diseases driven by perturbed RNA editing events. Herein, we review the current state of knowledge on the regulatory mechanisms governing A-to-I editing and propose the role of other co-factors that may be involved in this complex regulatory process. This review discusses the current state of knowledge on the mechanisms adopted in regulation of Adenosine-to-Inosine RNA editing.
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21
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Laletin V, Bykov Y. General anesthetics as a factor of effective neuroprotection in ischemic stroke models. ACTA ACUST UNITED AC 2015; 61:440-8. [DOI: 10.18097/pbmc20156104440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Stroke is the second leading cause of death in the world. Unfortunately, only a few drugs have been proved in clinical trials. Drug development of the last decade has been focused substantially on a promising and heterogeneous group of neuroprotective drugs. Hundreds of compounds were suggested as new putative neuroprotectors, which effectiveness was confirmed in preclinical trials only. At the present time discrepancy between results of preclinical studies and clinical trials requires careful analysis. One of the least evaluated and probably the most noticeable reasons is general anesthesia - an obligatory component of an overwhelming majority of existing animal stroke models. The aim of the review is to describe known mechanisms of common general anesthetics influence on ionotropic and metabotropic plasma membrane receptors, and key signal pathways involved in neuronal hypoxic-ischemic injury and survival
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Affiliation(s)
- V.S. Laletin
- Irkutsk State Medical University, Irkutsk, Russia
| | - Y.N. Bykov
- Irkutsk State Medical University, Irkutsk, Russia
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22
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Baicalin reverse AMPA receptor expression and neuron apoptosis in chronic unpredictable mild stress rats. Biochem Biophys Res Commun 2014; 451:467-72. [DOI: 10.1016/j.bbrc.2014.07.041] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/07/2014] [Indexed: 11/18/2022]
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23
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Differential effects of prenatal chronic high-decibel noise and music exposure on the excitatory and inhibitory synaptic components of the auditory cortex analog in developing chicks (Gallus gallus domesticus). Neuroscience 2014; 269:302-17. [DOI: 10.1016/j.neuroscience.2014.03.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/28/2014] [Accepted: 03/28/2014] [Indexed: 02/06/2023]
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24
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Advances in cellular models to explore the pathophysiology of amyotrophic lateral sclerosis. Mol Neurobiol 2013; 49:966-83. [PMID: 24198229 DOI: 10.1007/s12035-013-8573-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/15/2013] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS), the most common adult-onset motor neuron disorder, is fatal for most patients less than 3 years from when the first symptoms appear. The aetiologies for sporadic and most familial forms of ALS are unknown, but genetic factors are increasingly recognized as causal in a subset of patients. Studies of disease physiology suggest roles for oxidative stress, glutamate-mediated excitotoxicity or protein aggregation; how these pathways interact in the complex pathophysiology of ALS awaits elucidation. Cellular models are being used to examine disease mechanisms. Recent advances include the availability of expanded cell types, from neuronal or glial cell culture to motoneuron-astrocyte co-culture genetically or environmentally modified. Cell culture experiments confirmed the central role of glial cells in ALS. The recent adaptation of induced pluripotent stem cells (iPSC) for ALS modeling could allow a broader perspective and is expected to generate new hypotheses, related particularly to mechanisms underlying genetic factors. Cellular models have provided meaningful advances in the understanding of ALS, but, to date, complete characterization of in vitro models is only partially described. Consensus on methodological approaches, strategies for validation and techniques that allow rapid adaptation to new genetic or environmental influences is needed. In this article, we review the principal cellular models being employed in ALS and highlight their contribution to the understanding of disease mechanisms. We conclude with recommendations on means to enhance the robustness and generalizability of the different concepts for experimental ALS.
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25
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Tang XJ, Xing F. Calcium-permeable AMPA receptors in neonatal hypoxic-ischemic encephalopathy (Review). Biomed Rep 2013; 1:828-832. [PMID: 24649036 DOI: 10.3892/br.2013.154] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/18/2013] [Indexed: 11/06/2022] Open
Abstract
Hypoxic-ischemic encephalopathy (HIE) is an important cause of brain injury in the newborn and may result in long-term devastating consequences. Excessive stimulation of glutamate receptors (GluRs) is a pivotal mechanism underlying ischemia-induced selective and delayed neuronal death. Although initial studies focused on N-methyl-D-aspartic acid (NMDA) receptors as critical mediators in HIE, subsequent studies supported a more central role for α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPARs), particularly Ca2+-permeable AMPARs, in brain damage associated with hypoxia-ischemia. This study reviewed the important role of Ca2+-permeable AMPARs in HIE and the future potential neuroprotective strategies associated with Ca2+-permeable AMPARs.
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Affiliation(s)
- Xiao-Juan Tang
- Department of Neonatology, Children's Hospital Affiliated to Soochow University, Suzhou, Jiangsu 215003, P.R. China
| | - Feng Xing
- Department of Neonatology, Children's Hospital Affiliated to Soochow University, Suzhou, Jiangsu 215003, P.R. China
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26
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Yelskaya Z, Carrillo V, Dubisz E, Gulzar H, Morgan D, Mahajan SS. Synergistic inhibition of survival, proliferation, and migration of U87 cells with a combination of LY341495 and Iressa. PLoS One 2013; 8:e64588. [PMID: 23724064 PMCID: PMC3664620 DOI: 10.1371/journal.pone.0064588] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 04/16/2013] [Indexed: 11/18/2022] Open
Abstract
Glioblastomas exploit various molecular pathways to promote glutamate- dependent growth by activating the AMPA (2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl) propanoic acid) receptor, the group II metabotropic glutamate receptor, mGluR, and the epidermal growth factor receptor, EGFR. We hypothesized that targeting more than one of these pathways would be more effective in inhibiting glutamate-dependent growth. Using a model of U87 cell line, we show that blocking glutamate release by Riluzole inhibits cell proliferation. Glutamate-dependent growth is effectively inhibited by a combination of Iressa, an inhibitor of EGFR activation and LY341495, a group II mGluR inhibitor. Treatment of U87 cells with a combination of Iressa and LY341495 inhibits proliferation as indicated by Ki-67 staining, induces apoptosis and inhibits migration of U87 cells more effectively than the treatment by Iressa or LY341495 alone. These results demonstrate that a combinatorial therapy with Iressa and LY341495 is more effective due to synergistic effects of these drugs in inhibiting the growth of glioblastoma.
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Affiliation(s)
- Zarina Yelskaya
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Vangie Carrillo
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Ewa Dubisz
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Hira Gulzar
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Devon Morgan
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Shahana S. Mahajan
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
- * E-mail:
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27
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Chang PKY, Verbich D, McKinney RA. AMPA receptors as drug targets in neurological disease - advantages, caveats, and future outlook. Eur J Neurosci 2012; 35:1908-16. [DOI: 10.1111/j.1460-9568.2012.08165.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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28
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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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29
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Profound downregulation of the RNA editing enzyme ADAR2 in ALS spinal motor neurons. Neurobiol Dis 2011; 45:1121-8. [PMID: 22226999 DOI: 10.1016/j.nbd.2011.12.033] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/08/2011] [Accepted: 12/17/2011] [Indexed: 02/03/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common adult-onset fatal motor neuron disease. In spinal motor neurons of patients with sporadic ALS, normal RNA editing of GluA2, a subunit of the L-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, is inefficient. Adenosine deaminase acting on RNA 2 (ADAR2) specifically mediates RNA editing at the glutamine/arginine (Q/R) site of GluA2 and motor neurons expressing Q/R site-unedited GluA2 undergo slow death in conditional ADAR2 knockout mice. Therefore, investigation into whether inefficient ADAR2-mediated GluA2 Q/R site-editing occurs universally in motor neurons of patients with ALS would provide insight into the pathogenesis of ALS. We analyzed the extents of GluA2 Q/R site-editing in an individual laser-captured motor neuron of 29 ALS patients compared with those of normal and disease control subjects. In addition, we analyzed the enzymatic activity of three members of the ADAR family (ADAR1, ADAR2 and ADAR3) in ALS motor neurons expressing unedited GluA2 mRNA and those expressing only edited GluA2 mRNA. Q/R site-unedited GluA2 mRNA was expressed in a significant proportion of motor neurons from all of the ALS cases examined. Conversely, motor neurons of the normal and disease control subjects expressed only edited GluA2 mRNA. ADAR2, but not ADAR1 or ADAR3, was significantly downregulated in all the motor neurons of ALS patients, more extensively in those expressing Q/R site-unedited GluA2 mRNA than those expressing only Q/R site-edited GluA2 mRNA. These results indicate that ADAR2 downregulation is a profound pathological change relevant to death of motor neurons in ALS.
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30
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Orlandi C, Barbon A, Barlati S. Activity Regulation of Adenosine Deaminases Acting on RNA (ADARs). Mol Neurobiol 2011; 45:61-75. [DOI: 10.1007/s12035-011-8220-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 11/09/2011] [Indexed: 01/01/2023]
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31
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Weiss JH. Ca permeable AMPA channels in diseases of the nervous system. Front Mol Neurosci 2011; 4:42. [PMID: 22102834 PMCID: PMC3214733 DOI: 10.3389/fnmol.2011.00042] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 10/27/2011] [Indexed: 12/30/2022] Open
Abstract
Since the discovery and molecular characterization of Ca(2+)-permeable AMPA channels just over two decades ago, a large body of evidence has accumulated implicating contributions of these unusual glutamate activated channels to selective neurodegeneration in certain conditions, including ischemia and amyotrophic lateral sclerosis. Factors likely involved in their contributions to disease include their distinct patterns of expression in certain neuronal populations, their upregulation via various mechanisms in response to disease associated stresses, and their high permeability to Zn(2+) as well as to Ca(2+). However, full characterization of their contributions to certain diseases as well as development of therapeutics has been limited by the lack of selective and bioavailable blockers of these channels that can be employed in animals or humans. This review summarizes some of the clues that have emerged over recent years to the contributions of these channels in disease.
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Affiliation(s)
- John H Weiss
- Department of Neurology, University of California Irvine Irvine, CA, USA
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Hideyama T, Kwak S. When Does ALS Start? ADAR2-GluA2 Hypothesis for the Etiology of Sporadic ALS. Front Mol Neurosci 2011; 4:33. [PMID: 22102833 PMCID: PMC3214764 DOI: 10.3389/fnmol.2011.00033] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 10/03/2011] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. More than 90% of ALS cases are sporadic, and the majority of sporadic ALS patients do not carry mutations in genes causative of familial ALS; therefore, investigation specifically targeting sporadic ALS is needed to discover the pathogenesis. The motor neurons of sporadic ALS patients express unedited GluA2 mRNA at the Q/R site in a disease-specific and motor neuron-selective manner. GluA2 is a subunit of the AMPA receptor, and it has a regulatory role in the Ca2+-permeability of the AMPA receptor after the genomic Q codon is replaced with the R codon in mRNA by adenosine–inosine conversion, which is mediated by adenosine deaminase acting on RNA 2 (ADAR2). Therefore, ADAR2 activity may not be sufficient to edit all GluA2 mRNA expressed in the motor neurons of ALS patients. To investigate whether deficient ADAR2 activity plays pathogenic roles in sporadic ALS, we generated genetically modified mice (AR2) in which the ADAR2 gene was conditionally knocked out in the motor neurons. AR2 mice showed an ALS-like phenotype with the death of ADAR2-lacking motor neurons. Notably, the motor neurons deficient in ADAR2 survived when they expressed only edited GluA2 in AR2/GluR-BR/R (AR2res) mice, in which the endogenous GluA2 alleles were replaced by the GluR-BR allele that encoded edited GluA2. In heterozygous AR2 mice with only one ADAR2 allele, approximately 20% of the spinal motor neurons expressed unedited GluA2 and underwent degeneration, indicating that half-normal ADAR2 activity is not sufficient to edit all GluA2 expressed in motor neurons. It is likely therefore that the expression of unedited GluA2 causes the death of motor neurons in sporadic ALS. We hypothesize that a progressive downregulation of ADAR2 activity plays a critical role in the pathogenesis of sporadic ALS and that the pathological process commences when motor neurons express unedited GluA2.
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Affiliation(s)
- Takuto Hideyama
- Core Research for Evolutional Science and Technology, Japan Science Technology Agency Kawaguchi-shi, Saitama, Japan
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AMPA receptor regulation at the mRNA and protein level in rat primary cortical cultures. PLoS One 2011; 6:e25350. [PMID: 21966506 PMCID: PMC3178644 DOI: 10.1371/journal.pone.0025350] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 09/01/2011] [Indexed: 11/19/2022] Open
Abstract
Ionotropic glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are the major mediators of fast synaptic neurotransmission. In this work, we used primary cortical cultures from rats as a model system to study AMPA receptor regulation during in vitro cell maturation and after synaptic activity modifications. The levels of AMPA receptor mRNA and protein, along with the alternative splicing and RNA editing of the AMPA receptor subunit (GluR1-4) mRNAs, were analyzed in immature (DIV5) and mature (DIV26) rat neuronal cultures. We observed an increase in the expression of all four AMPA receptor subunits during in vitro neuronal maturation. This finding might be due to the formation of new synapses between neurons during the development of a complex neuronal network. We also analyzed the effects of stimulation (KCl and glutamate) and inhibition (APV/TTX) on rat mature neuronal cultures (DIV26): stimulation with KCl led to an overall down-regulation of GluR1 and GluR3 AMPA receptor subunits and an up-regulation of the GluR2 subunit. Similarly, glutamate treatment induced a significant down-regulation of GluR1 together with an up-regulation of GluR2. In contrast, the chronic blockade of neuronal activity that resulted from APV/TTX treatment up-regulated GluR1 and GluR3 with a parallel down-regulation of GluR2 and GluR4. RNA editing at the R/G site increased during neuronal cell maturation for all AMPA receptors (from 8–39% at DIV5 to 28–67% at DIV26). Unexpectedly, all the treatments tested induced a marked reduction (ranging from −9% to −52%) of R/G editing levels in mature neurons, primarily for the mRNA flip variant. In summary, we showed that cultured rat cortical neurons are able to vary the stoichiometric ratios of the AMPA receptor subunits and to control post-transcriptional processes to adapt fast synaptic transmission under different environmental conditions.
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