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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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Phosphorylation of Serine 157 Protects the Rat Glycine Transporter GlyT2 from Calpain Cleavage. J Mol Neurosci 2020; 70:1216-1224. [PMID: 32172509 DOI: 10.1007/s12031-020-01529-4] [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: 11/05/2019] [Accepted: 03/03/2020] [Indexed: 11/25/2022]
Abstract
The N-terminal region of the rat glycine transporter 2 (rGlyT2, SLC6A5) is cleaved by calpain protease in vitro, which raises the question of its protection against calpain in vivo. Here, we used a phosphomimetic and orthogonal phosphoserine translation approach to investigate the possible role of phosphorylation in the protection of two calpain cleavage sites, M156/S157 and G164/T165, previously identified in the N-terminus region of the rat GlyT2. Replacement of serine 157 with phosphomimetic aspartate or with orthogonal phosphoserine blocked both calpain cleavage sites and caused an electrophoretic mobility shift of rGlyT2N fusion proteins. Both effects can be reversed by dephosphorylation, suggesting that phosphorylation might induce structural changes in the rGlyT2 N-terminus, preventing the accessibility of the M156/S157 and G164/T165 cleavage sites to calpain in vivo. In comparison with the wild type, the phosphomimetic mutation S157D increased the total immunoreactivity of the transporter expressed in neuroblastoma cells, suggesting that serine 157 phosphorylation or phosphorylation-regulated calpain cleavage might contribute to the turnover of the glycine transporter GlyT2.
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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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Costa JT, Mele M, Baptista MS, Gomes JR, Ruscher K, Nobre RJ, de Almeida LP, Wieloch T, Duarte CB. Gephyrin Cleavage in In Vitro Brain Ischemia Decreases GABAA Receptor Clustering and Contributes to Neuronal Death. Mol Neurobiol 2015; 53:3513-3527. [PMID: 26093381 DOI: 10.1007/s12035-015-9283-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/02/2015] [Indexed: 02/01/2023]
Abstract
GABA (γ-aminobutyric acid) is the major inhibitory neurotransmitter in the central nervous system, and changes in GABAergic neurotransmission modulate the activity of neuronal networks. Gephyrin is a scaffold protein responsible for the traffic and synaptic anchoring of GABAA receptors (GABAAR); therefore, changes in gephyrin expression and oligomerization may affect the activity of GABAergic synapses. In this work, we investigated the changes in gephyrin protein levels during brain ischemia and in excitotoxic conditions, which may affect synaptic clustering of GABAAR. We found that gephyrin is cleaved by calpains following excitotoxic stimulation of hippocampal neurons with glutamate, as well as after intrahippocampal injection of kainate, giving rise to a stable cleavage product. Gephyrin cleavage was also observed in cultured hippocampal neurons subjected to transient oxygen-glucose deprivation (OGD), an in vitro model of brain ischemia, and after transient middle cerebral artery occlusion (MCAO) in mice, a model of focal brain ischemia. Furthermore, a truncated form of gephyrin decreased the synaptic clustering of the protein, reduced the synaptic pool of GABAAR containing γ2 subunits and upregulated OGD-induced cell death in hippocampal cultures. Our results show that excitotoxicity and brain ischemia downregulate full-length gephyrin with a concomitant generation of truncated products, which affect synaptic clustering of GABAAR and cell death.
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Affiliation(s)
- João T Costa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Coimbra, 3030-789, Portugal
| | - Márcio S Baptista
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - João R Gomes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Karsten Ruscher
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, S-22184, Lund, Sweden
| | - Rui J Nobre
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Coimbra, 3030-789, Portugal
| | - Luís Pereira de Almeida
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Tadeusz Wieloch
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, S-22184, Lund, Sweden
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal. .,Department of Life Sciences, University of Coimbra, 3004-517, Coimbra, Portugal. .,Center for Neuroscience and Cell Biology, Faculty of Medicine, Polo I, Rua Larga, University of Coimbra, 3004-504, Coimbra, Portugal.
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Fenker KE, Stanfield GM. SNF-10 connects male-derived signals to the onset of sperm motility in C. elegans. WORM 2015; 4:e1003002. [PMID: 26430556 PMCID: PMC4588553 DOI: 10.1080/21624054.2014.1003002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 12/09/2014] [Accepted: 12/22/2014] [Indexed: 10/23/2022]
Abstract
Sperm from the nematode C. elegans gain motility during a process termed activation, which they initiate in response to specific environmental signals. During this process, a number of subcellular rearrangements occur, culminating in an altered morphology that allows the cell to crawl toward and fertilize oocytes. Both hermaphrodites and males produce sperm, and redundant, sex-biased pathways regulate the sperm's activation. The male-derived signal for sperm activation involves TRY-5, a trypsin-like serine protease in seminal fluid, but until recently it was unknown what factors were active downstream of TRY-5. In our recent paper, we reported the discovery of SNF-10, a solute carrier 6 (SLC6) family protein that is expressed by sperm and connects the activation signal to changes in sperm morphology and, ultimately, the onset of motility. Here, we review our recent results, focusing on potential models for SNF-10's function in C. elegans, and additionally discuss the role SLC6 transporters may play in male reproductive biology from invertebrates to mammals.
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Affiliation(s)
- Kristin E Fenker
- Department of Human Genetics; University of Utah; Salt Lake City, UT USA
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Fenker KE, Hansen AA, Chong CA, Jud MC, Duffy BA, Norton JP, Hansen JM, Stanfield GM. SLC6 family transporter SNF-10 is required for protease-mediated activation of sperm motility in C. elegans. Dev Biol 2014; 393:171-82. [PMID: 24929237 DOI: 10.1016/j.ydbio.2014.06.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/28/2014] [Accepted: 06/03/2014] [Indexed: 11/18/2022]
Abstract
Motility of sperm is crucial for their directed migration to the egg. The acquisition and modulation of motility are regulated to ensure that sperm move when and where needed, thereby promoting reproductive success. One specific example of this phenomenon occurs during differentiation of the ameboid sperm of Caenorhabditis elegans as they activate from a round spermatid to a mature, crawling spermatozoon. Sperm activation is regulated by redundant pathways to occur at a specific time and place for each sex. Here, we report the identification of the solute carrier 6 (SLC6) transporter protein SNF-10 as a key regulator of C. elegans sperm activation in response to male protease activation signals. We find that SNF-10 is present in sperm and is required for activation by the male but not by the hermaphrodite. Loss of both snf-10 and a hermaphrodite activation factor render sperm completely insensitive to activation. Using in vitro assays, we find that snf-10 mutant sperm show a specific deficit in response to protease treatment but not to other activators. Prior to activation, SNF-10 is present in the plasma membrane, where it represents a strong candidate to receive signals that lead to subcellular morphogenesis. After activation, it shows polarized localization to the cell body region that is dependent on membrane fusions mediated by the dysferlin FER-1. Our discovery of snf-10 offers insight into the mechanisms differentially employed by the two sexes to accomplish the common goal of producing functional sperm, as well as how the physiology of nematode sperm may be regulated to control motility as it is in mammals.
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Affiliation(s)
- Kristin E Fenker
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - Angela A Hansen
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - Conrad A Chong
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - Molly C Jud
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - Brittany A Duffy
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - J Paul Norton
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - Jody M Hansen
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA
| | - Gillian M Stanfield
- Department of Human Genetics, University of Utah, 15 North 2030 East, Room 6110B, Salt Lake City, UT 84112, USA.
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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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Jursky F, Baliova M. Expression and purification of recombinant calpain-derived N-terminal peptides from glycine transporter GlyT2. Protein Expr Purif 2013; 88:143-9. [DOI: 10.1016/j.pep.2012.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 11/15/2022]
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Baptista MS, Melo CV, Armelão M, Herrmann D, Pimentel DO, Leal G, Caldeira MV, Bahr BA, Bengtson M, Almeida RD, Duarte CB. Role of the proteasome in excitotoxicity-induced cleavage of glutamic acid decarboxylase in cultured hippocampal neurons. PLoS One 2010; 5:e10139. [PMID: 20405034 PMCID: PMC2853570 DOI: 10.1371/journal.pone.0010139] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Accepted: 03/16/2010] [Indexed: 12/22/2022] Open
Abstract
Glutamic acid decarboxylase is responsible for synthesizing GABA, the major inhibitory neurotransmitter, and exists in two isoforms—GAD65 and GAD67. The enzyme is cleaved under excitotoxic conditions, but the mechanisms involved and the functional consequences are not fully elucidated. We found that excitotoxic stimulation of cultured hippocampal neurons with glutamate leads to a time-dependent cleavage of GAD65 and GAD67 in the N-terminal region of the proteins, and decrease the corresponding mRNAs. The cleavage of GAD67 was sensitive to the proteasome inhibitors MG132, YU102 and lactacystin, and was also abrogated by the E1 ubiquitin ligase inhibitor UBEI-41. In contrast, MG132 and UBEI-41 were the only inhibitors tested that showed an effect on GAD65 cleavage. Excitotoxic stimulation with glutamate also increased the amount of GAD captured in experiments where ubiquitinated proteins and their binding partners were isolated. However, no evidences were found for direct GADs ubiquitination in cultured hippocampal neurons, and recombinant GAD65 was not cleaved by purified 20S or 26S proteasome preparations. Since calpains, a group of calcium activated proteases, play a key role in GAD65/67 cleavage under excitotoxic conditions the results suggest that GADs are cleaved after ubiquitination and degradation of an unknown binding partner by the proteasome. The characteristic punctate distribution of GAD65 along neurites of differentiated cultured hippocampal neurons was significantly reduced after excitotoxic injury, and the total GAD activity measured in extracts from the cerebellum or cerebral cortex at 24h postmortem (when there is a partial cleavage of GADs) was also decreased. The results show a role of the UPS in the cleavage of GAD65/67 and point out the deregulation of GADs under excitotoxic conditions, which is likely to affect GABAergic neurotransmission. This is the first time that the UPS has been implicated in the events triggered during excitotoxicity and the first molecular target of the UPS affected in this cell death process.
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Affiliation(s)
- Márcio S. Baptista
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Carlos V. Melo
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
- * E-mail:
| | - Mário Armelão
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Dennis Herrmann
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Diogo O. Pimentel
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Graciano Leal
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Margarida V. Caldeira
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ben A. Bahr
- Biotechnology Research and Training Center, University of North Carolina, Pembroke, North Carolina, United States of America
| | - Mário Bengtson
- Department of Cancer and Cell Biology, Genomics Institute of the Novartis Research Foundation (GNF), San Diego, California, United States of America
| | - Ramiro D. Almeida
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Carlos B. Duarte
- Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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