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Nimgampalle M, Chakravarthy H, Sharma S, Shree S, Bhat AR, Pradeepkiran JA, Devanathan V. Neurotransmitter systems in the etiology of major neurological disorders: Emerging insights and therapeutic implications. Ageing Res Rev 2023; 89:101994. [PMID: 37385351 DOI: 10.1016/j.arr.2023.101994] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/21/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
Neurotransmitters serve as chemical messengers playing a crucial role in information processing throughout the nervous system, and are essential for healthy physiological and behavioural functions in the body. Neurotransmitter systems are classified as cholinergic, glutamatergic, GABAergic, dopaminergic, serotonergic, histaminergic, or aminergic systems, depending on the type of neurotransmitter secreted by the neuron, allowing effector organs to carry out specific functions by sending nerve impulses. Dysregulation of a neurotransmitter system is typically linked to a specific neurological disorder. However, more recent research points to a distinct pathogenic role for each neurotransmitter system in more than one neurological disorder of the central nervous system. In this context, the review provides recently updated information on each neurotransmitter system, including the pathways involved in their biochemical synthesis and regulation, their physiological functions, pathogenic roles in diseases, current diagnostics, new therapeutic targets, and the currently used drugs for associated neurological disorders. Finally, a brief overview of the recent developments in neurotransmitter-based therapeutics for selected neurological disorders is offered, followed by future perspectives in that area of research.
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Affiliation(s)
- Mallikarjuna Nimgampalle
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | - Harshini Chakravarthy
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India.
| | - Sapana Sharma
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | - Shruti Shree
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | - Anoop Ramachandra Bhat
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | | | - Vasudharani Devanathan
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India.
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Modi JP, Shen W, Menzie-Suderam J, Xu H, Lin CH, Tao R, Prentice HM, Schloss J, Wu JY. The Role of NMDA Receptor Partial Antagonist, Carbamathione, as a Therapeutic Agent for Transient Global Ischemia. Biomedicines 2023; 11:1885. [PMID: 37509524 PMCID: PMC10377037 DOI: 10.3390/biomedicines11071885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
Carbamathione (Carb), an NMDA glutamate receptor partial antagonist, has potent neuroprotective functions against hypoxia- or ischemia-induced neuronal injury in cell- or animal-based stroke models. We used PC-12 cell cultures as a cell-based model and bilateral carotid artery occlusion (BCAO) for stroke. Whole-cell patch clamp recording in the mouse retinal ganglion cells was performed. Key proteins involved in apoptosis, endoplasmic reticulum (ER) stress, and heat shock proteins were analyzed using immunoblotting. Carb is effective in protecting PC12 cells against glutamate- or hypoxia-induced cell injury. Electrophysiological results show that Carb attenuates NMDA-mediated glutamate currents in the retinal ganglion cells, which results in activation of the AKT signaling pathway and increased expression of pro-cell survival biomarkers, e.g., Hsp 27, P-AKT, and Bcl2 and decreased expression of pro-cell death markers, e.g., Beclin 1, Bax, and Cleaved caspase 3, and ER stress markers, e.g., CHOP, IRE1, XBP1, ATF 4, and eIF2α. Using the BCAO animal stroke model, we found that Carb reduced the brain infarct volume and decreased levels of ER stress markers, GRP 78, CHOP, and at the behavioral level, e.g., a decrease in asymmetric turns and an increase in locomotor activity. These findings for Carb provide promising and rational strategies for stroke therapy.
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Affiliation(s)
- Jigar Pravinchandra Modi
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Wen Shen
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Janet Menzie-Suderam
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Hongyuan Xu
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Chun-Hua Lin
- Department of Nursing, Kang-Ning University, Taipei 11485, Taiwan
| | - Rui Tao
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Howard M Prentice
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - John Schloss
- Department of Pharmaceutical Science, American University of Health Sciences, Signal Hill, CA 90755, USA
| | - Jang-Yen Wu
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL 33431, USA
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Morin post-treatment surpassed calpeptin in ameliorating 3-NP-induced cortical neurotoxicity via modulation of glutamate/calpain axis, Kidins220, and BDNF/TrkB/AKT/CREB trajectory. Int Immunopharmacol 2023; 116:109771. [PMID: 36736222 DOI: 10.1016/j.intimp.2023.109771] [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: 10/12/2022] [Revised: 01/13/2023] [Accepted: 01/20/2023] [Indexed: 02/04/2023]
Abstract
The neuroprotective capacity of morin hydrate (MH), a potent antioxidant flavonoid, and calpeptin (CP), a calpain inhibitor, was documented against different insults but not Huntington's disease (HD). Accordingly, we aim to assess the neuroprotective potential of MH and/or CP in a 3-nitropropionic acid (3-NP)-induced HD model. The 3-NP-treated rats were post-treated with saline, MH, CP, or MH + CP for a week. Post-treatment with MH and/or CP amended motor function (beam walking test) and short-/ long-term spatial memory (novel object recognition test) and improved cortical microscopic architecture. On the molecular level, MH, and to a lesser extent CP, inhibited the cortical content/expression of glutamate, calpain, and Kidins220 and abated the inflammatory molecules, nuclear factor (NF)-κB, tumor necrosis factor-α, and interleukin-1β, as well as lipid peroxidation. However, MH, but barely CP, activated the molecules of the neuroprotective trajectory; viz., brain-derived neurotrophic factor (BDNF), tropomyosin-related kinase receptor B (TrkB), protein kinase B (AKT), and cAMP response element-binding protein (CREB). Compared to the single treatments, the combination regimen mediated further reductions in the cortical contents of glutamate, calpain, and Kidins220, effects that extended to entail the anti-inflammatory/anti-oxidant potentials of MH and to a greater extent CP. However, the combination of MH strengthened the fair effect of CP on the survival signaling pathway BDNF/TrkB/AKT/CREB. In conclusion, MH, CP, and especially their combination, afforded neuroprotection against HD through curbing the glutamate/calpain axis, Kidins220, as well as NF-κB-mediated neuroinflammation/oxidative stress, besides activating the BDNF/TrkB/AKT/CREB hub that was partly dependent on calpain inhibition.
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Kamat V, Radtke JR, Hu Q, Wang W, Sweet IR, Hampe CS. Autoantibodies directed against glutamate decarboxylase interfere with glucose-stimulated insulin secretion in dispersed rat islets. Int J Exp Pathol 2022; 103:140-148. [PMID: 35246889 PMCID: PMC9264341 DOI: 10.1111/iep.12437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/17/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
Islet autoantibodies, including autoantibodies directed against the 65kDa isoform of glutamate decarboxylase (GAD65Ab), are present in the majority of patients with newly diagnosed type 1 diabetes (T1D). Whereas these autoantibodies are historically viewed as an epiphenomenon of the autoimmune response with no significant pathogenic function, we consider in this study the possibility that they impact the major islet function, namely glucose-stimulated insulin secretion. Two human monoclonal GAD65Ab (GAD65 mAb) (b78 and b96.11) were investigated for uptake by live rat beta cells, subcellular localization and their effect on glucose-stimulated insulin secretion. The GAD65 mAbs were internalized by live pancreatic beta cells, where they localized to subcellular structures in an epitope-specific manner. Importantly, GAD65 mAb b78 inhibited, while GAD65 mAb b96.11 enhanced, glucose-stimulated insulin secretion (GSIS). These opposite effects on GSIS rule out non-specific effects of the antibodies and suggest that internalization of the antibody leads to epitope-specific interaction with intracellular machinery regulating insulin granule release. The most likely explanation for the alteration of GSIS by GAD65 Abs is via changes in GABA release due to inhibition or change in GAD65 enzyme activity. This is the first report indicating an active role of GAD65Ab in the pathogenesis of T1D.
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Affiliation(s)
- Varun Kamat
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Jared R Radtke
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Qingxun Hu
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Wang Wang
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Ian R Sweet
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Christiane S Hampe
- Department of Medicine, University of Washington, Seattle, Washington, USA
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Modi J, Menzie-Suderam J, Xu H, Trujillo P, Medley K, Marshall ML, Tao R, Prentice H, Wu JY. Mode of action of granulocyte-colony stimulating factor (G-CSF) as a novel therapy for stroke in a mouse model. J Biomed Sci 2020; 27:19. [PMID: 31907023 PMCID: PMC6943893 DOI: 10.1186/s12929-019-0597-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/27/2019] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The FDA approved drug granulocyte-colony stimulating factor (G-CSF) displays anti-apoptotic and immunomodulatory properties with neurogenesis and angiogenic functions. It is known to demonstrate neuroprotective mechanisms against ischemic global stroke. Autophagy is a method for the degradation of intracellular components and in particular, unrestrained autophagy may lead to uncontrolled digestion of affected neurons as well as neuronal death in cerebral ischemia. Mitochondrial dynamics is vital for the regulation of cell survival and death after cerebral ischemia and an early upstream event in neuronal death is mitochondrial fission. We examined the pro-survival mechanisms of G-CSF against apoptosis resulting from autophagy, mitochondrial stress and endoplasmic reticulum (ER) stress. METHODS Male Swiss Webster mice (20 weeks of age) were subjected to bilateral common carotid artery occlusion (BCAO) for 30 min. After occlusion, mice were injected with G-CSF (50 μg/kg) subcutaneously for 4 days. Behavioral analysis was carried out using the corner test and locomotor activity test before animals were sacrificed on day 4 or day 7. Key proteins in ER stress, autophagy and mitochondrial stress induced apoptosis were analyzed by immunoblotting. RESULTS G-CSF improved neurological deficits and improved behavioral performance on corner and locomotor test. G-CSF binds to G-CSF receptors and its activation leads to upregulation of Akt phosphorylation (P-Akt) which in turn decreases levels of the ER stress sensor, GRP 78 and expression of proteins involved in ER stress apoptosis pathway; ATF6, ATF4, eIF2α, XBP1, Caspase 12 and CHOP. G-CSF treatment significantly decreased Beclin-1, an autophagy marker, and decreased mitochondrial stress biomarkers DRP1 and P53. G-CSF also up-regulated the mitochondrial fusion protein, OPA1 and anti-apoptotic protein Bcl-2 while down-regulating the pro-apoptotic proteins Bax, Bak and PUMA. CONCLUSIONS G-CSF is an endogenous ligand in the CNS that has a dual activity that is beneficial both in reducing acute neuronal degeneration and adding to long-term plasticity after cerebral ischemia. G-CSF treatment exerts neuroprotective effects on damaged neurons through the suppression of the ER stress and mitochondrial stress and maintains cellular homeostasis by decreasing pro-apoptotic proteins and increasing of anti-apoptotic proteins.
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Affiliation(s)
- Jigar Modi
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
- Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, USA
| | - Janet Menzie-Suderam
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Hongyuan Xu
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Paola Trujillo
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Kristen Medley
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | | | - Rui Tao
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Howard Prentice
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA.
- Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, USA.
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, 33431, USA.
| | - Jang-Yen Wu
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA.
- Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, USA.
- Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, 33431, USA.
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The regulation of glutamic acid decarboxylases in GABA neurotransmission in the brain. Arch Pharm Res 2019; 42:1031-1039. [PMID: 31786745 DOI: 10.1007/s12272-019-01196-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/26/2019] [Indexed: 12/18/2022]
Abstract
Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter that is required for the control of synaptic excitation/inhibition and neural oscillation. GABA is synthesized by glutamic acid decarboxylases (GADs) that are widely distributed and localized to axon terminals of inhibitory neurons as well as to the soma and, to a lesser extent, dendrites. The expression and activity of GADs is highly correlated with GABA levels and subsequent GABAergic neurotransmission at the inhibitory synapse. Dysregulation of GADs has been implicated in various neurological disorders including epilepsy and schizophrenia. Two isoforms of GADs, GAD67 and GAD65, are expressed from separate genes and have different regulatory processes and molecular properties. This review focuses on the recent advances in understanding the structure of GAD, its transcriptional regulation and post-transcriptional modifications in the central nervous system. This may provide insights into the pathological mechanisms underlying neurological diseases that are associated with GAD dysfunction.
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The Roles of GABA in Ischemia-Reperfusion Injury in the Central Nervous System and Peripheral Organs. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:4028394. [PMID: 31814874 PMCID: PMC6878816 DOI: 10.1155/2019/4028394] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 09/27/2019] [Accepted: 10/18/2019] [Indexed: 12/30/2022]
Abstract
Ischemia-reperfusion (I/R) injury is a common pathological process, which may lead to dysfunctions and failures of multiple organs. A flawless medical way of endogenous therapeutic target can illuminate accurate clinical applications. γ-Aminobutyric acid (GABA) has been known as a marker in I/R injury of the central nervous system (mainly in the brain) for a long time, and it may play a vital role in the occurrence of I/R injury. It has been observed that throughout cerebral I/R, levels, syntheses, releases, metabolisms, receptors, and transmissions of GABA undergo complex pathological variations. Scientists have investigated the GABAergic enhancers for attenuating cerebral I/R injury; however, discussions on existing problems and mechanisms of available drugs were seldom carried out so far. Therefore, this review would summarize the process of pathological variations in the GABA system under cerebral I/R injury and will cover corresponding probable issues and mechanisms in using GABA-related drugs to illuminate the concern about clinical illness for accurately preventing cerebral I/R injury. In addition, the study will summarize the increasing GABA signals that can prevent I/R injuries occurring in peripheral organs, and the roles of GABA were also discussed correspondingly.
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Downregulation of glutamic acid decarboxylase in Drosophila TDP-43-null brains provokes paralysis by affecting the organization of the neuromuscular synapses. Sci Rep 2018; 8:1809. [PMID: 29379112 PMCID: PMC5789004 DOI: 10.1038/s41598-018-19802-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/05/2018] [Indexed: 11/12/2022] Open
Abstract
Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects the motor system, comprised of motoneurons and associated glia. Accordingly, neuronal or glial defects in TDP-43 function provoke paralysis due to the degeneration of the neuromuscular synapses in Drosophila. To identify the responsible molecules and mechanisms, we performed a genome wide proteomic analysis to determine differences in protein expression between wild-type and TDP-43-minus fly heads. The data established that mutant insects presented reduced levels of the enzyme glutamic acid decarboxylase (Gad1) and increased concentrations of extracellular glutamate. Genetic rescue of Gad1 activity in neurons or glia was sufficient to recuperate flies locomotion, synaptic organization and glutamate levels. Analogous recovery was obtained by treating TDP-43-null flies with glutamate receptor antagonists demonstrating that Gad1 promotes synapses formation and prevents excitotoxicity. Similar suppression of TDP-43 provoked the downregulation of GAD67, the Gad1 homolog protein in human neuroblastoma cell lines and analogous modifications were observed in iPSC-derived motoneurons from patients carrying mutations in TDP-43, uncovering conserved pathological mechanisms behind the disease.
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Modi J, Prentice H, Wu JY. Preparation, Stimulation and Other Uses of Adult Rat Brain Synaptosomes. Bio Protoc 2017; 7:e2664. [PMID: 34595322 DOI: 10.21769/bioprotoc.2664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/16/2017] [Accepted: 11/30/2017] [Indexed: 11/02/2022] Open
Abstract
In this paper, our protocol for preparation of brain synaptosomes is described. Synaptosomes are a valuable model system for analysis of structural components of the synapse as well as for investigation of synaptic function. Synaptosomal preparations are necessary for understanding molecular changes at synapses where critical post-translational modifications of synaptic proteins may occur. Not only are synaptosomes rich in synaptic proteins, but they can be used for analyzing uptake of neurotransmitters into synaptic vesicles and for analysis of the involvement of neurotransmitter synthesis and release. Synaptosomes can be stimulated with increased calcium influx to release neurotransmitters. Synaptosomal preparations have been used in characterizing calcium dependent phosphorylation and activation of the GABA synthesizing enzyme GAD65 (L-glutamic acid decarboxylase with molecular weight of 65 kDa). By examining protein complexes on the membrane of synaptic vesicles obtained from synaptosomal preparations, it was possible to characterize the role of GAD65 in the coupled synthesis and vesicular uptake of GABA (γ-aminobutyric acid) culminating in GABA vesicular release, which contributes in an important way to fine-tuning of GABAergic neurotransmission.
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Affiliation(s)
- Jigar Modi
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.,Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, USA
| | - Howard Prentice
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.,Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, USA.,Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, USA
| | - Jang-Yen Wu
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.,Center of Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL, USA.,Program in Integrative Biology, Florida Atlantic University, Boca Raton, FL, USA
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Lee SA, Huang KC. Epigenetic profiling of human brain differential DNA methylation networks in schizophrenia. BMC Med Genomics 2016; 9:68. [PMID: 28117656 PMCID: PMC5260790 DOI: 10.1186/s12920-016-0229-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Epigenetics of schizophrenia provides important information on how the environmental factors affect the genetic architecture of the disease. DNA methylation plays a pivotal role in etiology for schizophrenia. Previous studies have focused mostly on the discovery of schizophrenia-associated SNPs or genetic variants. As postmortem brain samples became available, more and more recent studies surveyed transcriptomics of the diseases. In this study, we constructed protein-protein interaction (PPI) network using the disease associated SNP (or genetic variants), differentially expressed disease genes and differentially methylated disease genes (or promoters). By combining the different datasets and topological analyses of the PPI network, we established a more comprehensive understanding of the development and genetics of this devastating mental illness. Results We analyzed the previously published DNA methylation profiles of prefrontal cortex from 335 healthy controls and 191 schizophrenic patients. These datasets revealed 2014 CpGs identified as GWAS risk loci with the differential methylation profile in schizophrenia, and 1689 schizophrenic differential methylated genes (SDMGs) identified with predominant hypomethylation. These SDMGs, combined with the PPIs of these genes, were constructed into the schizophrenic differential methylation network (SDMN). On the SDMN, there are 10 hypermethylated SDMGs, including GNA13, CAPNS1, GABPB2, GIT2, LEFTY1, NDUFA10, MIOS, MPHOSPH6, PRDM14 and RFWD2. The hypermethylation to differential expression network (HyDEN) were constructed to determine how the hypermethylated promoters regulate gene expression. The enrichment analyses of biochemical pathways in HyDEN, including TNF alpha, PDGFR-beta signaling, TGF beta Receptor, VEGFR1 and VEGFR2 signaling, regulation of telomerase, hepatocyte growth factor receptor signaling, ErbB1 downstream signaling and mTOR signaling pathway, suggested that the malfunctioning of these pathways contribute to the symptoms of schizophrenia. Conclusions The epigenetic profiles of DNA differential methylation from schizophrenic brain samples were investigated to understand the regulatory roles of SDMGs. The SDMGs interplays with SCZCGs in a coordinated fashion in the disease mechanism of schizophrenia. The protein complexes and pathways involved in SDMN may be responsible for the etiology and potential treatment targets. The SDMG promoters are predominantly hypomethylated. Increasing methylation on these promoters is proposed as a novel therapeutic approach for schizophrenia. Electronic supplementary material The online version of this article (doi:10.1186/s12920-016-0229-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sheng-An Lee
- Department of Information Management, Kainan University, Taoyuan, Taiwan
| | - Kuo-Chuan Huang
- Department of Psychiatry, Beitou Branch, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. .,Department of Nursing, Ching Kuo Institute of Management and Health, Keelung, Taiwan.
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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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Li M, Qiu L, Wang L, Wang W, Xin L, Li Y, Liu Z, Song L. The inhibitory role of γ-aminobutyric acid (GABA) on immunomodulation of Pacific oyster Crassostrea gigas. FISH & SHELLFISH IMMUNOLOGY 2016; 52:16-22. [PMID: 26975413 DOI: 10.1016/j.fsi.2016.03.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 03/03/2016] [Accepted: 03/10/2016] [Indexed: 05/15/2023]
Abstract
γ-aminobutyric acid (GABA) is an inhibitory neurotransmitter to suppress the immune-mediated pro-inflammatory reactions, and it has been used in the treatment of many inflammation-related diseases in vertebrates, while its immunomodulatory role in invertebrates has never been reported. In the present study, GABA was found to exist in the hemolymph of Pacific oyster Crassostrea gigas, and its concentration decreased slightly from 8.00 ± 0.37 μmol L(-1) at normal condition to 7.73 ± 0.15 μmol L(-1) at 6 h after LPS stimulation, and then increased to 9.34 ± 0.15 μmol L(-1), 8.86 ± 0.68 μmol L(-1) at 12 h and 48 h, respectively. After LPS stimulation, the mRNA expressions of pro-inflammatory cytokines (CgIL-17 and CgTNF) and immune effectors (CgSOD and CgBPI), and the protein expression of NOS increased significantly, and these increased trends were remarkably inhibited by GABA stimulation. At the same time, the phagocytosis rate and apoptosis rate of immunocytes also increased obviously after LPS stimulation, whereas the increase was repressed with the addition of GABA. The results collectively demonstrated that GABA was an indispensable inhibitory agent for both humoral and cellular immune response, which mainly functioned at the late phase of immune response to avoid the excess immune reactions and maintain the immune homeostasis.
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Affiliation(s)
- Meijia Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Limei Qiu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lingling Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China.
| | - Weilin Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lusheng Xin
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiqun Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaoqun Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Linsheng Song
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China
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Activation of Brain L-glutamate Decarboxylase 65 Isoform (GAD65) by Phosphorylation at Threonine 95 (T95). Mol Neurobiol 2016; 54:866-873. [DOI: 10.1007/s12035-015-9633-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/15/2015] [Indexed: 11/26/2022]
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14
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Manto M, Honnorat J, Hampe CS, Guerra-Narbona R, López-Ramos JC, Delgado-García JM, Saitow F, Suzuki H, Yanagawa Y, Mizusawa H, Mitoma H. Disease-specific monoclonal antibodies targeting glutamate decarboxylase impair GABAergic neurotransmission and affect motor learning and behavioral functions. Front Behav Neurosci 2015; 9:78. [PMID: 25870548 PMCID: PMC4375997 DOI: 10.3389/fnbeh.2015.00078] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/12/2015] [Indexed: 12/21/2022] Open
Abstract
Autoantibodies to the smaller isoform of glutamate decarboxylase (GAD) can be found in patients with type 1 diabetes and a number of neurological disorders, including stiff-person syndrome, cerebellar ataxia and limbic encephalitis. The detection of disease-specific autoantibody epitopes led to the hypothesis that distinct GAD autoantibodies may elicit specific neurological phenotypes. We explored the in vitro/in vivo effects of well-characterized monoclonal GAD antibodies. We found that GAD autoantibodies present in patients with stiff person syndrome (n = 7) and cerebellar ataxia (n = 15) recognized an epitope distinct from that recognized by GAD autoantibodies present in patients with type 1 diabetes mellitus (n = 10) or limbic encephalitis (n = 4). We demonstrated that the administration of a monoclonal GAD antibody representing this epitope specificity; (1) disrupted in vitro the association of GAD with γ-Aminobutyric acid containing synaptic vesicles; (2) depressed the inhibitory synaptic transmission in cerebellar slices with a gradual time course and a lasting suppressive effect; (3) significantly decreased conditioned eyelid responses evoked in mice, with no modification of learning curves in the classical eyeblink-conditioning task; (4) markedly impaired the facilitatory effect exerted by the premotor cortex over the motor cortex in a paired-pulse stimulation paradigm; and (5) induced decreased exploratory behavior and impaired locomotor function in rats. These findings support the specific targeting of GAD by its autoantibodies in the pathogenesis of stiff-person syndrome and cerebellar ataxia. Therapies of these disorders based on selective removal of such GAD antibodies could be envisioned.
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Affiliation(s)
- Mario Manto
- Unité d'Etude du Mouvement, FNRS Neurologie, ULB Erasme Brussels, Belgium
| | | | | | | | | | | | - Fumihito Saitow
- Department of Pharmacology, Nippon Medical School Tokyo, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Nippon Medical School Tokyo, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine and JST, CREST, Maebashi City Gunma, Japan
| | | | - Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University Tokyo, Japan
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15
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Lower glutamic acid decarboxylase 65-kDa isoform messenger RNA and protein levels in the prefrontal cortex in schizoaffective disorder but not schizophrenia. Biol Psychiatry 2015; 77:167-76. [PMID: 24993056 PMCID: PMC4247819 DOI: 10.1016/j.biopsych.2014.05.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 05/13/2014] [Accepted: 05/21/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND Altered gamma-aminobutyric acid (GABA) signaling in the prefrontal cortex (PFC) has been associated with cognitive dysfunction in patients with schizophrenia and schizoaffective disorder. Levels of the GABA-synthesizing enzyme glutamic acid decarboxylase 67-kDa isoform (GAD67) in the PFC have been consistently reported to be lower in patients with these disorders, but the status of the second GABA-synthesizing enzyme, glutamic acid decarboxylase 65-kDa isoform (GAD65), remains unclear. METHODS GAD65 messenger RNA (mRNA) levels were quantified in PFC area 9 by quantitative polymerase chain reaction from 62 subjects with schizophrenia or schizoaffective disorder and 62 matched healthy comparison subjects. In a subset of subject pairs, GAD65 relative protein levels were quantified by confocal immunofluorescence microscopy. RESULTS Mean GAD65 mRNA levels were 13.6% lower in subjects with schizoaffective disorder but did not differ in subjects with schizophrenia relative to their matched healthy comparison subjects. In the subjects with schizoaffective disorder, mean GAD65 protein levels were 19.4% lower and were correlated with GAD65 mRNA levels. Lower GAD65 mRNA and protein levels within subjects with schizoaffective disorder were not attributable to factors commonly comorbid with the diagnosis. CONCLUSIONS In concert with previous studies, these findings suggest that schizoaffective disorder is associated with lower levels of both GAD65 and GAD67 mRNA and protein in the PFC, whereas subjects with schizophrenia have lower mean levels of only GAD67 mRNA and protein. Because cognitive function is generally better preserved in patients with schizoaffective disorder relative to patients with schizophrenia, these findings may support an interpretation that GAD65 downregulation provides a homeostatic response complementary to GAD67 downregulation that serves to reduce inhibition in the face of lower PFC network activity.
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16
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Modi JP, Gharibani PM, Ma Z, Tao R, Menzie J, Prentice H, Wu JY. Protective mechanism of sulindac in an animal model of ischemic stroke. Brain Res 2014; 1576:91-9. [DOI: 10.1016/j.brainres.2014.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/16/2014] [Accepted: 06/16/2014] [Indexed: 02/06/2023]
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17
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Glutamate and GABA-Metabolizing Enzymes in Post-mortem Cerebellum in Alzheimer’s Disease: Phosphate-Activated Glutaminase and Glutamic Acid Decarboxylase. THE CEREBELLUM 2014; 13:607-15. [DOI: 10.1007/s12311-014-0573-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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18
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Kaila K, Ruusuvuori E, Seja P, Voipio J, Puskarjov M. GABA actions and ionic plasticity in epilepsy. Curr Opin Neurobiol 2014; 26:34-41. [PMID: 24650502 DOI: 10.1016/j.conb.2013.11.004] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 10/23/2013] [Accepted: 11/06/2013] [Indexed: 11/18/2022]
Abstract
Concepts of epilepsy, based on a simple change in neuronal excitation/inhibition balance, have subsided in face of recent insights into the large diversity and context-dependence of signaling mechanisms at the molecular, cellular and neuronal network level. GABAergic transmission exerts both seizure-suppressing and seizure-promoting actions. These two roles are prone to short-term and long-term alterations, evident both during epileptogenesis and during individual epileptiform events. The driving force of GABAergic currents is controlled by ion-regulatory molecules such as the neuronal K-Cl cotransporter KCC2 and cytosolic carbonic anhydrases. Accumulating evidence suggests that neuronal ion regulation is highly plastic, thereby contributing to the multiple roles ascribed to GABAergic signaling during epileptogenesis and epilepsy.
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Affiliation(s)
- Kai Kaila
- Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland; Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Eva Ruusuvuori
- Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland; Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland
| | - Patricia Seja
- Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland; Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland
| | - Juha Voipio
- Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland
| | - Martin Puskarjov
- Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland; Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland
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19
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Varshavsky A. Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis. Protein Sci 2012; 21:1634-61. [PMID: 22930402 PMCID: PMC3527701 DOI: 10.1002/pro.2148] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 08/21/2012] [Indexed: 02/05/2023]
Abstract
Despite extensive understanding of sleep regulation, the molecular-level cause and function of sleep are unknown. I suggest that they originate in individual neurons and stem from increased production of protein fragments during wakefulness. These fragments are transient parts of protein complexes in which the fragments were generated. Neuronal Ca²⁺ fluxes are higher during wakefulness than during sleep. Subunits of transmembrane channels and other proteins are cleaved by Ca²⁺-activated calpains and by other nonprocessive proteases, including caspases and secretases. In the proposed concept, termed the fragment generation (FG) hypothesis, sleep is a state during which the production of fragments is decreased (owing to lower Ca²⁺ transients) while fragment-destroying pathways are upregulated. These changes facilitate the elimination of fragments and the remodeling of protein complexes in which the fragments resided. The FG hypothesis posits that a proteolytic cleavage, which produces two fragments, can have both deleterious effects and fitness-increasing functions. This (previously not considered) dichotomy can explain both the conservation of cleavage sites in proteins and the evolutionary persistence of sleep, because sleep would counteract deleterious aspects of protein fragments. The FG hypothesis leads to new explanations of sleep phenomena, including a longer sleep after sleep deprivation. Studies in the 1970s showed that ethanol-induced sleep in mice can be strikingly prolonged by intracerebroventricular injections of either Ca²⁺ alone or Ca²⁺ and its ionophore (Erickson et al., Science 1978;199:1219-1221; Harris, Pharmacol Biochem Behav 1979;10:527-534; Erickson et al., Pharmacol Biochem Behav 1980;12:651-656). These results, which were never interpreted in connection to protein fragments or the function of sleep, may be accounted for by the FG hypothesis about molecular causation of sleep.
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Affiliation(s)
- Alexander Varshavsky
- Division of Biology, California Institute of Technology, Pasadena, California 91125, USA.
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20
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Sebe JY, Bershteyn M, Hirotsune S, Wynshaw-Boris A, Baraban SC. ALLN rescues an in vitro excitatory synaptic transmission deficit in Lis1 mutant mice. J Neurophysiol 2012; 109:429-36. [PMID: 23100132 DOI: 10.1152/jn.00431.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
LIS1 gene mutations lead to a rare neurological disorder, classical lissencephaly, characterized by brain malformations, mental retardation, seizures, and premature death. Mice heterozygous for Lis1 (Lis1(+/-)) exhibit cortical malformations, defects in neuronal migration, increased glutamate-mediated synaptic transmission, and spontaneous electrographic seizures. Recent work demonstrated that in utero treatment of Lis1(+/-) mutant dams with ALLN, a calpain inhibitor, partially rescues neuronal migration defects in the offspring. Given the challenges of in utero drug administration, we examined the therapeutic potential of ALLN on postnatal lissencephalic cells. Voltage- and current-clamp studies were performed with acute hippocampal slices obtained from Lis1 mutant mice and age-matched littermate control mice. Specifically, we determined whether postnatal ALLN treatment can reverse excitatory synaptic transmission deficits, namely, an increase in spontaneous and miniature excitatory postsynaptic current (EPSC) frequency, on CA1 pyramidal neurons observed in tissue slices from Lis1(+/-) mice. We found that acute application of ALLN restored spontaneous and miniature EPSC frequencies to wild-type levels without affecting inhibitory postsynaptic synaptic current. Furthermore, Western blot analysis of protein expression, including proteins involved in excitatory synaptic transmission, demonstrated that ALLN blocks the cleavage of the calpain substrate αII-spectrin but does not rescue Lis1 protein levels in Lis1(+/-) mutants.
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Affiliation(s)
- Joy Y Sebe
- Epilepsy Research Laboratory, Department of Neurological Surgery, University of California, San Francisco, California 94143, USA
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21
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Puskarjov M, Ahmad F, Kaila K, Blaesse P. Activity-dependent cleavage of the K-Cl cotransporter KCC2 mediated by calcium-activated protease calpain. J Neurosci 2012; 32:11356-64. [PMID: 22895718 PMCID: PMC6621186 DOI: 10.1523/jneurosci.6265-11.2012] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 06/29/2012] [Accepted: 07/03/2012] [Indexed: 11/21/2022] Open
Abstract
The K-Cl cotransporter KCC2 plays a crucial role in neuronal chloride regulation. In mature central neurons, KCC2 is responsible for the low intracellular Cl(-) concentration ([Cl(-)](i)) that forms the basis for hyperpolarizing GABA(A) receptor-mediated responses. Fast changes in KCC2 function and expression have been observed under various physiological and pathophysiological conditions. Here, we show that the application of protein synthesis inhibitors cycloheximide and emetine to acute rat hippocampal slices have no effect on total KCC2 protein level and K-Cl cotransporter function. Furthermore, blocking constitutive lysosomal degradation with leupeptin did not induce significant changes in KCC2 protein levels. These findings indicate a low basal turnover rate of the total KCC2 protein pool. In the presence of the glutamate receptor agonist NMDA, the total KCC2 protein level decreased to about 30% within 4 h, and this effect was blocked by calpeptin and MDL-28170, inhibitors of the calcium-activated protease calpain. Interictal-like activity induced by incubation of hippocampal slices in an Mg(2+)-free solution led to a fast reduction in KCC2-mediated Cl(-) transport efficacy in CA1 pyramidal neurons, which was paralleled by a decrease in both total and plasmalemmal KCC2 protein. These effects were blocked by the calpain inhibitor MDL-28170. Taken together, these findings show that calpain activation leads to cleavage of KCC2, thereby modulating GABAergic signaling.
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Affiliation(s)
- Martin Puskarjov
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
| | - Faraz Ahmad
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
| | - Kai Kaila
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
| | - Peter Blaesse
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
- Institute of Physiology I, Westfälische Wilhelms-University Münster, D-48149 Münster, Germany
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