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Phelan KD, Shwe UT, Wu H, Zheng F. Investigating Contributions of Canonical Transient Receptor Potential Channel 3 to Hippocampal Hyperexcitability and Seizure-Induced Neuronal Cell Death. Int J Mol Sci 2024; 25:6260. [PMID: 38892448 PMCID: PMC11172528 DOI: 10.3390/ijms25116260] [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: 04/15/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
Canonical transient receptor potential channel 3 (TRPC3) is the most abundant TRPC channel in the brain and is highly expressed in all subfields of the hippocampus. Previous studies have suggested that TRPC3 channels may be involved in the hyperexcitability of hippocampal pyramidal neurons and seizures. Genetic ablation of TRPC3 channel expression reduced the intensity of pilocarpine-induced status epilepticus (SE). However, the underlying cellular mechanisms remain unexplored and the contribution of TRPC3 channels to SE-induced neurodegeneration is not determined. In this study, we investigated the contribution of TRPC3 channels to the electrophysiological properties of hippocampal pyramidal neurons and hippocampal synaptic plasticity, and the contribution of TRPC3 channels to seizure-induced neuronal cell death. We found that genetic ablation of TRPC3 expression did not alter basic electrophysiological properties of hippocampal pyramidal neurons and had a complex impact on epileptiform bursting in CA3. However, TRPC3 channels contribute significantly to long-term potentiation in CA1 and SE-induced neurodegeneration. Our results provided further support for therapeutic potential of TRPC3 inhibitors and raised new questions that need to be answered by future studies.
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Affiliation(s)
- Kevin D. Phelan
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
| | - U Thaung Shwe
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Hong Wu
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Fang Zheng
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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2
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Zong P, Legere N, Feng J, Yue L. TRP Channels in Excitotoxicity. Neuroscientist 2024:10738584241246530. [PMID: 38682490 DOI: 10.1177/10738584241246530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Glutamate excitotoxicity is a central mechanism contributing to cellular dysfunction and death in various neurological disorders and diseases, such as stroke, traumatic brain injury, epilepsy, schizophrenia, addiction, mood disorders, Huntington's disease, Alzheimer's disease, Parkinson's disease, multiple sclerosis, pathologic pain, and even normal aging-related changes. This detrimental effect emerges from glutamate binding to glutamate receptors, including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, N-methyl-d-aspartate receptors, kainate receptors, and GluD receptors. Thus, excitotoxicity could be prevented by targeting glutamate receptors and their downstream signaling pathways. However, almost all the glutamate receptor antagonists failed to attenuate excitotoxicity in human patients, mainly due to the limited understanding of the underlying mechanisms regulating excitotoxicity. Transient receptor potential (TRP) channels serve as ancient cellular sensors capable of detecting and responding to both external and internal stimuli. The study of human TRP channels has flourished in recent decades since the initial discovery of mammalian TRP in 1995. These channels have been found to play pivotal roles in numerous pathologic conditions, including excitotoxicity. In this review, our focus centers on exploring the intricate interactions between TRP channels and glutamate receptors in excitotoxicity.
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Affiliation(s)
- Pengyu Zong
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConn Health), Farmington, CT, USA
- Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
| | - Nicholas Legere
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConn Health), Farmington, CT, USA
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Jianlin Feng
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConn Health), Farmington, CT, USA
| | - Lixia Yue
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConn Health), Farmington, CT, USA
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3
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Zheng F, Phelan KD, Shwe UT. Increased Susceptibility to Pilocarpine-Induced Status Epilepticus and Reduced Latency in TRPC1/4 Double Knockout Mice. Neurol Int 2023; 15:1469-1479. [PMID: 38132974 PMCID: PMC10745782 DOI: 10.3390/neurolint15040095] [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: 11/13/2023] [Revised: 12/01/2023] [Accepted: 12/02/2023] [Indexed: 12/23/2023] Open
Abstract
Canonical transient receptor potential channels (TRPCs) are a family of calcium-permeable cation channels. Previous studies have shown that heteromeric channels comprising TRPC1 and TRPC4 mediate epileptiform bursting in lateral septal neurons and hippocampal CA1 pyramidal neurons, suggesting that TRPC1/4 channels play a pro-seizure role. In this study, we utilized electroencephalography (EEG) recording and spectral analysis to assess the role of TRPC1/4 channels in the pilocarpine model of status epilepticus (SE). We found that, surprisingly, TRPC1/4 double knockout (DKO) mice exhibited an increased susceptibility to pilocarpine-induced SE. Furthermore, SE latency was also significantly reduced in TRPC1/4 DKO mice. Further studies are needed to reveal the underlying mechanisms of our unexpected results.
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Affiliation(s)
- Fang Zheng
- Department of Pharmacology & Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
- Department of Neurobiology & Developmental Sciences, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
| | - U Thaung Shwe
- Department of Pharmacology & Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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4
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Jiang J, Yu Y. Pharmacologically targeting transient receptor potential channels for seizures and epilepsy: Emerging preclinical evidence of druggability. Pharmacol Ther 2023; 244:108384. [PMID: 36933703 PMCID: PMC10124570 DOI: 10.1016/j.pharmthera.2023.108384] [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: 01/06/2023] [Revised: 02/19/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023]
Abstract
As one of the most prevalent and disabling brain disorders, epilepsy is characterized by spontaneous seizures that result from aberrant, excessive hyperactivity of a group of highly synchronized brain neurons. Remarkable progress in epilepsy research and treatment over the first two decades of this century led to a dramatical expansion in the third-generation antiseizure drugs (ASDs). However, there are still over 30% of patients suffering from seizures resistant to the current medications, and the broad unbearable adversative effects of ASDs significantly impair the quality of life in about 40% of individuals affected by the disease. Prevention of epilepsy in those who are at high risks is another major unmet medical need, given that up to 40% of epilepsy patients are believed to have acquired causes. Therefore, it is important to identify novel drug targets that can facilitate the discovery and development of new therapies engaging unprecedented mechanisms of action that might overcome these significant limitations. Also over the last two decades, calcium signaling has been increasingly recognized as a key contributory factor in epileptogenesis of many aspects. The intracellular calcium homeostasis involves a variety of calcium-permeable cation channels, the most important of which perhaps are the transient receptor potential (TRP) ion channels. This review focuses on recent exciting advances in understanding of TRP channels in preclinical models of seizure disorders. We also provide emerging insights into the molecular and cellular mechanisms of TRP channels-engaged epileptogenesis that might lead to new antiseizure therapies, epilepsy prevention and modification, and even a cure.
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Affiliation(s)
- Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Center, Memphis, TN, United States.
| | - Ying Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Tennessee Health Science Center, Memphis, TN, United States.
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5
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Heydari FS, Gorji Valokola M, Mehri S, Abnous K, Roohbakhsh A. The blockade of transient receptor potential ankyrin 1 (TRPA1) protects against PTZ-induced seizure. Metab Brain Dis 2023; 38:621-630. [PMID: 36399240 DOI: 10.1007/s11011-022-01123-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/03/2022] [Indexed: 11/19/2022]
Abstract
Treatment of epilepsy remains a major problem as some epileptic patients do not respond to the current therapeutics. Transient receptor potential ankyrin 1 (TRPA1) belongs to the TRP channels and has diverse physiological functions in the body. Considering its physiological properties, we aimed to evaluate its role in two experimental models of epilepsy, including pentylenetetrazol (PTZ)-induced acute seizure and PTZ-evoked kindling. Furthermore, the TRPA1 protein levels were assessed in the cerebral cortex, hippocampus, and cerebellum after seizure induction. Three groups of Wistar rats received acute intraperitoneal injection of pentylenetetrazol (PTZ, 85 mg/kg). The groups received intraventricular injections of vehicle (dimethyl sulfoxide, Tween 80, and sterile 0.9% saline), valproate (30 µg/rat), or HC030031 (TRPA1 antagonist, 14 µg/rat) before PTZ injection. In the PTZ-induced kindling model, PTZ was administrated 35 mg/kg every other day for 24 days. PTZ gradually provoked seizure-related behaviors. After experiments, the TRPA1 levels in the brain were assessed using western blot. The results showed that HC030031 reduced the median of seizure scores and S5 duration while increasing S2 and S5 latencies in acute and kindling models. The anticonvulsant effect of HC030031 was comparable with valproate as a standard anticonvulsant drug. Furthermore, induction of seizure, either acute or kindling, enhanced TRPA1 levels in the cerebral cortex, hippocampus, and cerebellum that were prevented by HC030031 or valproate administration. The results of this study showed that HC030031 as a TRPA1 receptor antagonist promoted a significant anticonvulsant effect comparable with valproate. Both drugs prevented TRPA1 upregulation during seizures. These findings imply that TRPA1 is a potential target in treating epilepsy.
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Affiliation(s)
- Fatemeh Sadat Heydari
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Gorji Valokola
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmacology, Brain and Spinal Injury Repair Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Soghra Mehri
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Khalil Abnous
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
- Department of Medicinal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Ali Roohbakhsh
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
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6
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Yu Y, Li W, Jiang J. TRPC channels as emerging targets for seizure disorders. Trends Pharmacol Sci 2022; 43:787-798. [PMID: 35840362 PMCID: PMC9378536 DOI: 10.1016/j.tips.2022.06.007] [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: 03/30/2022] [Revised: 06/09/2022] [Accepted: 06/17/2022] [Indexed: 10/17/2022]
Abstract
Epilepsy is characterized by seizures of diverse types that affect about 1-2% of the population worldwide. Current antiseizure medications are unsatisfactory, as they merely provide symptomatic relief, are ineffective in about one-third of patients, and cause unbearable adverse effects. Transient receptor potential canonical (TRPC) channels are a group of nonselective cation channels involved in many physiological functions. In this review, we provide an overview of recent preclinical studies using both genetic and pharmacological strategies that reveal these receptor-operated calcium-permeable channels may also play fundamental roles in many aspects of epileptic seizures. We also propose that TRPC channels represent appealing targets for epilepsy treatment, with a goal of helping to advance the discovery and development of new antiseizure and/or antiepileptogenic therapies.
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Affiliation(s)
- Ying Yu
- Department of Pharmaceutical Sciences and Drug Discovery Center, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Wei Li
- Department of Pharmaceutical Sciences and Drug Discovery Center, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences and Drug Discovery Center, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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7
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Pétigny C, Dumont AA, Giguère H, Collette A, Holleran BJ, Iftinca M, Altier C, Besserer-Offroy É, Auger-Messier M, Leduc R. Monitoring TRPC7 Conformational Changes by BRET Following GPCR Activation. Int J Mol Sci 2022; 23:ijms23052502. [PMID: 35269644 PMCID: PMC8910688 DOI: 10.3390/ijms23052502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 02/06/2023] Open
Abstract
Transient receptor potential canonical (TRPC) channels are membrane proteins involved in regulating Ca2+ homeostasis, and whose functions are modulated by G protein-coupled receptors (GPCR). In this study, we developed bioluminescent resonance energy transfer (BRET) biosensors to better study channel conformational changes following receptor activation. For this study, two intramolecular biosensors, GFP10-TRPC7-RLucII and RLucII-TRPC7-GFP10, were constructed and were assessed following the activation of various GPCRs. We first transiently expressed receptors and the biosensors in HEK293 cells, and BRET levels were measured following agonist stimulation of GPCRs. The activation of GPCRs that engage Gαq led to a Gαq-dependent BRET response of the functional TRPC7 biosensor. Focusing on the Angiotensin II type-1 receptor (AT1R), GFP10-TRPC7-RLucII was tested in rat neonatal cardiac fibroblasts, expressing endogenous AT1R and TRPC7. We detected similar BRET responses in these cells, thus validating the use of the biosensor in physiological conditions. Taken together, our results suggest that activation of Gαq-coupled receptors induce conformational changes in a novel and functional TRPC7 BRET biosensor.
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Affiliation(s)
- Cécile Pétigny
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (C.P.); (A.C.); (B.J.H.)
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Audrey-Ann Dumont
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Department of Medicine, Division of Cardiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Hugo Giguère
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Department of Medicine, Division of Cardiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Audrey Collette
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (C.P.); (A.C.); (B.J.H.)
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Brian J. Holleran
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (C.P.); (A.C.); (B.J.H.)
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Mircea Iftinca
- Department of Physiology and Pharmacology, Inflammation Research Network-Snyder Institute for Chronic Diseases and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.I.); (C.A.)
| | - Christophe Altier
- Department of Physiology and Pharmacology, Inflammation Research Network-Snyder Institute for Chronic Diseases and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (M.I.); (C.A.)
| | - Élie Besserer-Offroy
- Department of Molecular and Medical Pharmacology, Ahmanson Translational Theranostics Division, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA;
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, Los Angeles, CA 90095, USA
| | - Mannix Auger-Messier
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Department of Medicine, Division of Cardiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Richard Leduc
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (C.P.); (A.C.); (B.J.H.)
- Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada; (A.-A.D.); (H.G.); (M.A.-M.)
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Correspondence:
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Distinct Morphological and Behavioural Alterations in ENU-Induced Heterozygous Trpc7K810Stop Mutant Mice. Genes (Basel) 2021; 12:genes12111732. [PMID: 34828338 PMCID: PMC8617871 DOI: 10.3390/genes12111732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Trpc7 (transient receptor potential cation channel, subfamily C, member 7; 862 amino acids) knockout mice are described showing no clear phenotypic alterations, therefore, the functional relevance of the gene remains unclear. A complementary approach for the functional analysis of a given gene is the examination of individuals harbouring a mutant allele of the gene. In the phenotype-driven Munich ENU mouse mutagenesis project, a high number of phenotypic parameters was used for establishing novel mouse models on the genetic background of C3H inbred mice. The phenotypically dominant mutant line SMA002 was established and further examined. Analysis of the causative mutation as well as the phenotypic characterization of the mutant line were carried out. The causative mutation was detected in the gene Trpc7 which leads to the production of a truncated protein due to the novel stop codon at amino acid position 810 thereby affecting the highly conserved cytoplasmic C terminus of the protein. Trpc7 heterozygous mutant mice of both sexes were viable and fertile, but showed distinct morphological and behavioural alterations which is in contrast to the published phenotype of Trpc7 knockout mice. Thus, the Trpc7K810Stop mutation leads to a dominant negative effect of the mutant protein.
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9
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García-Rodríguez C, Bravo-Tobar ID, Duarte Y, Barrio LC, Sáez JC. Contribution of non-selective membrane channels and receptors in epilepsy. Pharmacol Ther 2021; 231:107980. [PMID: 34481811 DOI: 10.1016/j.pharmthera.2021.107980] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/14/2022]
Abstract
Overcoming refractory epilepsy's resistance to the combination of antiepileptic drugs (AED), mitigating side effects, and preventing sudden unexpected death in epilepsy are critical goals for therapy of this disorder. Current therapeutic strategies are based primarily on neurocentric mechanisms, overlooking the participation of astrocytes and microglia in the pathophysiology of epilepsy. This review is focused on a set of non-selective membrane channels (permeable to ions and small molecules), including channels and ionotropic receptors of neurons, astrocytes, and microglia, such as: the hemichannels formed by Cx43 and Panx1; the purinergic P2X7 receptors; the transient receptor potential vanilloid (TRPV1 and TRPV4) channels; calcium homeostasis modulators (CALHMs); transient receptor potential canonical (TRPC) channels; transient receptor potential melastatin (TRPM) channels; voltage-dependent anion channels (VDACs) and volume-regulated anion channels (VRACs), which all have in common being activated by epileptic activity and the capacity to exacerbate seizure intensity. Specifically, we highlight evidence for the activation of these channels/receptors during epilepsy including neuroinflammation and oxidative stress, discuss signaling pathways and feedback mechanisms, and propose the functions of each of them in acute and chronic epilepsy. Studying the role of these non-selective membrane channels in epilepsy and identifying appropriate blockers for one or more of them could provide complementary therapies to better alleviate the disease.
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Affiliation(s)
- Claudia García-Rodríguez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Chile.
| | - Iván D Bravo-Tobar
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Chile
| | - Yorley Duarte
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Luis C Barrio
- Hospital Ramon y Cajal-IRYCIS, Centro de Tecnología Biomédica de la Universidad Politécnica, Madrid, Spain
| | - Juan C Sáez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Chile.
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10
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Chen X, Liu K, Lin Z, Huang K, Pan S. Knockout of Transient Receptor Potential Melastatin 4 Channel Mitigates Cerebral Edema and Neuronal Injury After Status Epilepticus in Mice. J Neuropathol Exp Neurol 2021; 79:1354-1364. [PMID: 33186453 DOI: 10.1093/jnen/nlaa134] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study aimed to evaluate whether the knockout of transient receptor potential melastatin 4 (TRPM4) could reduce cerebral edema and improve neurologic outcome in a mouse model of status epilepticus (SE). Wild-type (WT) (n = 61) and Trpm4-/- mice (n = 61) with behavioral seizures induced by lithium (10 mEq/kg) and pilocarpine (30-40 mg/kg) were terminated 2.5 hours after the onset of SE. After SE, 28 WT-SE and 27 Trpm4-/--SE mice were observed for 28 days and assessed for survival and cognitive function; the others were killed after 24 hours, 72 hours, or 7 days, and evaluated for cerebral edema and histological injury. In comparison to WT-SE mice, the mortality and cognitive deficit for Trpm4-/--SE mice following SE after 28 days were significantly ameliorated. Trpm4-/--SE mice also showed less water content and cerebral edema assessed by magnetic resonance imaging, and decreased blood-brain barrier breakdown after SE. Moreover, Trpm4 deficiency significantly mitigated neuronal loss, cellular necrosis and apoptosis in the hippocampus and piriform cortex and mitigated astrocytosis and microgliosis. In conclusion, this study suggests that Trmp4 may represent a new target for improving outcomes after SE.
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Affiliation(s)
- Xing Chen
- From the Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Kewei Liu
- From the Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhenzhou Lin
- From the Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Kaibin Huang
- From the Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Suyue Pan
- From the Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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11
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Lee K, Jo YY, Chung G, Jung JH, Kim YH, Park CK. Functional Importance of Transient Receptor Potential (TRP) Channels in Neurological Disorders. Front Cell Dev Biol 2021; 9:611773. [PMID: 33748103 PMCID: PMC7969799 DOI: 10.3389/fcell.2021.611773] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/09/2021] [Indexed: 12/11/2022] Open
Abstract
Transient receptor potential (TRP) channels are transmembrane protein complexes that play important roles in the physiology and pathophysiology of both the central nervous system (CNS) and the peripheral nerve system (PNS). TRP channels function as non-selective cation channels that are activated by several chemical, mechanical, and thermal stimuli as well as by pH, osmolarity, and several endogenous or exogenous ligands, second messengers, and signaling molecules. On the pathophysiological side, these channels have been shown to play essential roles in the reproductive system, kidney, pancreas, lung, bone, intestine, as well as in neuropathic pain in both the CNS and PNS. In this context, TRP channels have been implicated in several neurological disorders, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and epilepsy. Herein, we focus on the latest involvement of TRP channels, with a special emphasis on the recently identified functional roles of TRP channels in neurological disorders related to the disruption in calcium ion homeostasis.
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Affiliation(s)
- Kihwan Lee
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon, South Korea
| | - Youn Yi Jo
- Department of Anesthesiology and Pain Medicine, Gil Medical Center, Gachon University, Incheon, South Korea
| | - Gehoon Chung
- Department of Oral Physiology and Program in Neurobiology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Jung Hoon Jung
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Yong Ho Kim
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon, South Korea
| | - Chul-Kyu Park
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon, South Korea
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12
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Chen X, Sooch G, Demaree IS, White FA, Obukhov AG. Transient Receptor Potential Canonical (TRPC) Channels: Then and Now. Cells 2020; 9:E1983. [PMID: 32872338 PMCID: PMC7565274 DOI: 10.3390/cells9091983] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 12/13/2022] Open
Abstract
Twenty-five years ago, the first mammalian Transient Receptor Potential Canonical (TRPC) channel was cloned, opening the vast horizon of the TRPC field. Today, we know that there are seven TRPC channels (TRPC1-7). TRPCs exhibit the highest protein sequence similarity to the Drosophila melanogaster TRP channels. Similar to Drosophila TRPs, TRPCs are localized to the plasma membrane and are activated in a G-protein-coupled receptor-phospholipase C-dependent manner. TRPCs may also be stimulated in a store-operated manner, via receptor tyrosine kinases, or by lysophospholipids, hypoosmotic solutions, and mechanical stimuli. Activated TRPCs allow the influx of Ca2+ and monovalent alkali cations into the cytosol of cells, leading to cell depolarization and rising intracellular Ca2+ concentration. TRPCs are involved in the continually growing number of cell functions. Furthermore, mutations in the TRPC6 gene are associated with hereditary diseases, such as focal segmental glomerulosclerosis. The most important recent breakthrough in TRPC research was the solving of cryo-EM structures of TRPC3, TRPC4, TRPC5, and TRPC6. These structural data shed light on the molecular mechanisms underlying TRPCs' functional properties and propelled the development of new modulators of the channels. This review provides a historical overview of the major advances in the TRPC field focusing on the role of gene knockouts and pharmacological tools.
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Affiliation(s)
- Xingjuan Chen
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an 710072, China;
| | - Gagandeep Sooch
- The Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (G.S.); (I.S.D.)
| | - Isaac S. Demaree
- The Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (G.S.); (I.S.D.)
| | - Fletcher A. White
- The Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Alexander G. Obukhov
- The Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (G.S.); (I.S.D.)
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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How TRPC Channels Modulate Hippocampal Function. Int J Mol Sci 2020; 21:ijms21113915. [PMID: 32486187 PMCID: PMC7312571 DOI: 10.3390/ijms21113915] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 05/27/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
Transient receptor potential canonical (TRPC) proteins constitute a group of receptor-operated calcium-permeable nonselective cationic membrane channels of the TRP superfamily. They are largely expressed in the hippocampus and are able to modulate neuronal functions. Accordingly, they have been involved in different hippocampal functions such as learning processes and different types of memories, as well as hippocampal dysfunctions such as seizures. This review covers the mechanisms of activation of these channels, how these channels can modulate neuronal excitability, in particular the after-burst hyperpolarization, and in the persistent activity, how they control synaptic plasticity including pre- and postsynaptic processes and how they can interfere with cell survival and neurogenesis.
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14
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Involvement of TRPC4 and 5 Channels in Persistent Firing in Hippocampal CA1 Pyramidal Cells. Cells 2020; 9:cells9020365. [PMID: 32033274 PMCID: PMC7072216 DOI: 10.3390/cells9020365] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/29/2020] [Accepted: 02/01/2020] [Indexed: 12/17/2022] Open
Abstract
Persistent neural activity has been observed in vivo during working memory tasks, and supports short-term (up to tens of seconds) retention of information. While synaptic and intrinsic cellular mechanisms of persistent firing have been proposed, underlying cellular mechanisms are not yet fully understood. In vitro experiments have shown that individual neurons in the hippocampus and other working memory related areas support persistent firing through intrinsic cellular mechanisms that involve the transient receptor potential canonical (TRPC) channels. Recent behavioral studies demonstrating the involvement of TRPC channels on working memory make the hypothesis that TRPC driven persistent firing supports working memory a very attractive one. However, this view has been challenged by recent findings that persistent firing in vitro is unchanged in TRPC knock out (KO) mice. To assess the involvement of TRPC channels further, we tested novel and highly specific TRPC channel blockers in cholinergically induced persistent firing in mice CA1 pyramidal cells for the first time. The application of the TRPC4 blocker ML204, TRPC5 blocker clemizole hydrochloride, and TRPC4 and 5 blocker Pico145, all significantly inhibited persistent firing. In addition, intracellular application of TRPC4 and TRPC5 antibodies significantly reduced persistent firing. Taken together these results indicate that TRPC4 and 5 channels support persistent firing in CA1 pyramidal neurons. Finally, we discuss possible scenarios causing these controversial observations on the role of TRPC channels in persistent firing.
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15
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Günaydın C, Arslan G, Bilge SS. Proconvulsant effect of trans-cinnamaldehyde in pentylenetetrazole-induced kindling model of epilepsy: The role of TRPA1 channels. Neurosci Lett 2020; 721:134823. [PMID: 32035165 DOI: 10.1016/j.neulet.2020.134823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 12/27/2022]
Abstract
The transient receptor potential ankyrin 1 (TRPA1), a member of the TRP superfamily, is widely distributed in the central nervous system (CNS) and plays an important role in pain and inflammation. However, no data has been reported regarding the effects of TRPA1 on epileptic seizures. Thus, this study was designed to investigate the sub-chronic effect of trans-cinnamaldehyde (TCA), an agonist of TRPA1, in pentylenetetrazole (PTZ) induced kindling model via electrocorticography (ECoG). Furthermore, the expressions of cAMP response element binding protein (CREB), brain-derived neurotrophic factor (BDNF), and NMDA receptor subunit NR2B were measured using Western blotting. Rats were kindled by intraperitoneal (i.p.) PTZ (35 mg/kg) injections. After electrode implantation and healing period, 10 and 30 mg/kg TCA was given i.p. for 14 consecutive days. On the next day, ECoG recordings were obtained after the injection of PTZ (35 mg/kg, i.p.), and twenty-four hours later, rats were decapitated for molecular analyses. TCA, at a dose of 30 mg/kg, decreased the first myoclonic jerk latency and increased seizure duration and total spike activity. Additionally, both doses of TCA enhanced CREB, BDNF, and NR2B expressions, which were increased by the kindling. The evidence from this study suggests that long term activation of TRPA1 channels causes an exacerbated seizure activity. Moreover, PTZ-induced increases in CREB, BDNF, and NR2B levels were enhanced by the repeated administrations of TCA.
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Affiliation(s)
- Caner Günaydın
- Department of Pharmacology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Gökhan Arslan
- Department of Physiology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey.
| | - S Sırrı Bilge
- Department of Pharmacology, School of Medicine, Ondokuz Mayis University, Samsun, Turkey
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16
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Hsu W, Tsai M, Wu C, Liang J, Lu J, Kahle JS, Yu H, Yen C, Yen C, Hsieh Y, Huang Y, Lin L, Tsai T, Chen C, Yoshioka T. Nociceptive transient receptor potential canonical 7 (TRPC7) mediates aging-associated tumorigenesis induced by ultraviolet B. Aging Cell 2020; 19:e13075. [PMID: 31755176 PMCID: PMC6974716 DOI: 10.1111/acel.13075] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/21/2019] [Accepted: 10/25/2019] [Indexed: 12/14/2022] Open
Abstract
Aging, cancer, and longevity have been linked to intracellular Ca2+ signaling and nociceptive transient receptor potential (TRP) channels. We found that TRP canonical 7 (TRPC7) is a nociceptive mechanoreceptor and that TRPC7 channels specifically mediate the initiation of ultraviolet B (UVB)‐induced skin aging and tumor development due to p53 gene family mutations. Within 30 min after UVB irradiation, TRPC7 mediated UVB‐induced Ca2+ influx and the subsequent production of reactive oxygen species in skin cells. Notably, this function was unique to TRPC7 and was not observed for other TRP channels. In TRPC7 knockout mice, we did not observe the significant UVB‐associated pathology seen in wild‐type mice, including epidermal thickening, abnormal keratinocyte differentiation, and DNA damage response activation. TRPC7 knockout mice also had significantly fewer UVB‐induced cancerous tumors than did wild‐type mice, and UVB‐induced p53 gene family mutations were prevented in TRPC7 knockout mice. These results indicate that TRPC7 activity is pivotal in the initiation of UVB‐induced skin aging and tumorigenesis and that the reduction in TRPC7 activity suppresses the UVB‐induced aging process and tumor development. Our findings support that TRPC7 is a potential tumor initiator gene and that it causes cell aging and genomic instability, followed by a change in the activity of proto‐oncogenes and tumor suppressor genes to promote tumorigenesis.
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Affiliation(s)
- Wen‐Li Hsu
- Research Organization for Nano & Life Innovation Waseda University, Shinjuku Tokyo Japan
- Emerging Compounds Research Center General Research Service Center National Pingtung University of Science and Technology Pingtung Taiwan
- Regenerative Medicine and Cell Therapy Research Center Kaohsiung Medical University Kaohsiung Taiwan
| | - Ming‐Hsien Tsai
- Emerging Compounds Research Center General Research Service Center National Pingtung University of Science and Technology Pingtung Taiwan
- Department of Child Care College of Humanities and Social Sciences National Pingtung University of Science and Technology Pingtung Taiwan
| | - Ching‐Ying Wu
- Department of Dermatology Kaohsiung Municipal Ta‐Tung Hospital Kaohsiung Medical University Hospital Kaohsiung Medical University Kaohsiung Taiwan
- Graduate Institute of Medicine School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
| | - Jui‐Lin Liang
- Department of General Surgery Chi‐Mei Medical Center, Liouying Tainan Taiwan
| | - Jian‐He Lu
- Graduate Institute of Medicine School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
| | - Jennifer S. Kahle
- Department of Psychological Sciences University of San Diego San Diego CA USA
- BPS, International San Diego CA USA
| | - Hsin‐Su Yu
- Department of Dermatology Kaohsiung Medical University Kaohsiung Taiwan
| | - Chia‐Jung Yen
- Regenerative Medicine and Cell Therapy Research Center Kaohsiung Medical University Kaohsiung Taiwan
- Department of Child Care College of Humanities and Social Sciences National Pingtung University of Science and Technology Pingtung Taiwan
| | - Chen‐Tung Yen
- Department of Life Science National Taiwan University Taipei Taiwan
| | - Yi‐Chun Hsieh
- Emerging Compounds Research Center General Research Service Center National Pingtung University of Science and Technology Pingtung Taiwan
- Department of Child Care College of Humanities and Social Sciences National Pingtung University of Science and Technology Pingtung Taiwan
| | - Yung‐Yun Huang
- School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
| | - Li‐Ching Lin
- School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
| | - Tsung‐Fu Tsai
- School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
| | - Chu‐Huang Chen
- Graduate Institute of Medicine School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
- Center for Lipid Biosciences Kaohsiung Medical University Hospital Kaohsiung Medical University Kaohsiung Taiwan
- Vascular and Medicinal Research Texas Heart Institute Houston TX USA
- New York Heart Research Foundation Mineola NY USA
- Lipid Science and Aging Research Center Kaohsiung Medical University Kaohsiung Taiwan
| | - Tohru Yoshioka
- Regenerative Medicine and Cell Therapy Research Center Kaohsiung Medical University Kaohsiung Taiwan
- Graduate Institute of Medicine School of Medicine Kaohsiung Medical University Kaohsiung Taiwan
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17
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Knauer B, Yoshida M. Switching between persistent firing and depolarization block in individual rat CA1 pyramidal neurons. Hippocampus 2019; 29:817-835. [PMID: 30794330 DOI: 10.1002/hipo.23078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 12/22/2018] [Accepted: 01/15/2019] [Indexed: 11/07/2022]
Abstract
The hippocampal formation plays a role in mnemonic tasks and epileptic discharges in vivo. In vitro, these functions and malfunctions may relate to persistent firing (PF) and depolarization block (DB), respectively. Pyramidal neurons of the CA1 field have previously been reported to engage in either PF or DB during cholinergic stimulation. However, it is unknown whether these cells constitute disparate populations of neurons. Furthermore, it is unclear which cell-specific peculiarities may mediate their diverse response properties. However, it has not been shown whether individual CA1 pyramidal neurons can switch between PF and DB states. Here, we used whole cell patch clamp in the current clamp mode on in vitro CA1 pyramidal neurons from acutely sliced rat tissue to test various intrinsic properties which may provoke individual cells to switch between PF and DB. We found that individual cells could switch from PF to DB, in a cholinergic agonist concentration dependent manner and depending on the parameters of stimulation. We also demonstrate involvement of TRPC and potassium channels in this switching. Finally, we report that the probability for DB was more pronounced in the proximal than in the distal half of CA1. These findings offer a potential mechanism for the stronger spatial modulation in proximal, compared to distal CA1, as place field formation was shown to be affected by DB. Taken together, our results suggest that PF and DB are not mutually exclusive response properties of individual neurons. Rather, a cell's response mode depends on a variety of intrinsic properties, and modulation of these properties enables switching between PF and DB.
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Affiliation(s)
- Beate Knauer
- International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
- Faculty of Psychology, Mercator Research Group - Structure of Memory, Ruhr University Bochum, Bochum, Germany
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Motoharu Yoshida
- Faculty of Psychology, Mercator Research Group - Structure of Memory, Ruhr University Bochum, Bochum, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
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18
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Colangeli R, Di Maio R, Pierucci M, Deidda G, Casarrubea M, Di Giovanni G. Synergistic action of CB 1 and 5-HT 2B receptors in preventing pilocarpine-induced status epilepticus in rats. Neurobiol Dis 2019; 125:135-145. [PMID: 30716469 DOI: 10.1016/j.nbd.2019.01.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/24/2019] [Accepted: 01/31/2019] [Indexed: 11/30/2022] Open
Abstract
Endocannabinoids (eCBs) and serotonin (5-HT) play a neuromodulatory role in the central nervous system. Both eCBs and 5-HT regulate neuronal excitability and their pharmacological potentiation has been shown to control seizures in pre-clinical and human studies. Compelling evidence indicates that eCB and 5-HT systems interact to modulate several physiological and pathological brain functions, such as food intake, pain, drug addiction, depression, and anxiety. Nevertheless, there is no evidence of an eCB/5-HT interaction in experimental and human epilepsies, including status epilepticus (SE). Here, we performed video-EEG recording in behaving rats treated with the pro-convulsant agent pilocarpine (PILO), in order to study the effect of the activation of CB1/5-HT2 receptors and their interaction on SE. Synthetic cannabinoid agonist WIN55,212-2 (WIN) decreased behavioral seizure severity of PILO-induced SE at 2 mg/kg (but not at 1 and 5 mg/kg, i.p.), while 5-HT2B/2C receptor agonist RO60-0175 (RO; 1, 3, 10 mg/kg, i.p.) was devoid of any effect. RO 3 mg/kg was instead capable of potentiating the effect of WIN 2 mg/kg on the Racine scale score. Surprisingly, neither WIN 2 mg/kg nor RO 3 mg/kg had any effect on the incidence and the intensity of EEG seizures when administered alone. However, WIN+RO co-administration reduced the incidence and the severity of EEG SE and increased the latency to SE onset after PILO injection. WIN+RO effects were blocked by the selective CB1R antagonist AM251 and the 5-HT2BR antagonist RS127445, but not by the 5-HT2CR antagonist SB242084 or the 5-HT2AR antagonist MDL11,939. These data revealed a synergistic interaction between CB1R/5-HT2BR in the expression of PILO-induced SE.
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Affiliation(s)
- Roberto Colangeli
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.
| | - Roberto Di Maio
- Pittsburgh Inst. for Neurodegenerative Dis., Dept. of Neurology, Univ. of Pittsburgh, PA, USA
| | - Massimo Pierucci
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Gabriele Deidda
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Maurizio Casarrubea
- Department of Experimental Biomedicine and Clinical Neurosciences, Human Physiology Section "Giuseppe Pagano", University of Palermo, Palermo, Italy
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; School of Biosciences, Cardiff University, Cardiff, UK.
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19
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Lichtenegger M, Tiapko O, Svobodova B, Stockner T, Glasnov TN, Schreibmayer W, Platzer D, de la Cruz GG, Krenn S, Schober R, Shrestha N, Schindl R, Romanin C, Groschner K. An optically controlled probe identifies lipid-gating fenestrations within the TRPC3 channel. Nat Chem Biol 2018; 14:396-404. [PMID: 29556099 PMCID: PMC5903546 DOI: 10.1038/s41589-018-0015-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 01/12/2018] [Indexed: 12/30/2022]
Abstract
Transient receptor potential canonical (TRPC) channels TRPC3, TRPC6 and TRPC7 are able to sense the lipid messenger diacylglycerol (DAG). The DAG-sensing and lipid-gating processes in these ion channels are still unknown. To gain insights into the lipid-sensing principle, we generated a DAG photoswitch, OptoDArG, that enabled efficient control of TRPC3 by light. A structure-guided mutagenesis screen of the TRPC3 pore domain unveiled a single glycine residue behind the selectivity filter (G652) that is exposed to lipid through a subunit-joining fenestration. Exchange of G652 with larger residues altered the ability of TRPC3 to discriminate between different DAG molecules. Light-controlled activation-deactivation cycling of TRPC3 channels by an OptoDArG-mediated optical 'lipid clamp' identified pore domain fenestrations as pivotal elements of the channel´s lipid-sensing machinery. We provide evidence for a novel concept of lipid sensing by TRPC channels based on a lateral fenestration in the pore domain that accommodates lipid mediators to control gating.
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Affiliation(s)
- Michaela Lichtenegger
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | - Oleksandra Tiapko
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | - Barbora Svobodova
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Wolfgang Schreibmayer
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | - Dieter Platzer
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | | | - Sarah Krenn
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | - Romana Schober
- Institute of Biophysics, University of Linz, Linz, Austria
| | - Niroj Shrestha
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | - Rainer Schindl
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria
| | | | - Klaus Groschner
- Gottfried Schatz Research Center, Biophysics, Medical University of Graz, Graz, Austria,
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20
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Reboreda A, Theissen FM, Valero-Aracama MJ, Arboit A, Corbu MA, Yoshida M. Do TRPC channels support working memory? Comparing modulations of TRPC channels and working memory through G-protein coupled receptors and neuromodulators. Behav Brain Res 2018; 354:64-83. [PMID: 29501506 DOI: 10.1016/j.bbr.2018.02.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 02/27/2018] [Accepted: 02/27/2018] [Indexed: 12/11/2022]
Abstract
Working memory is a crucial ability we use in daily life. However, the cellular mechanisms supporting working memory still remain largely unclear. A key component of working memory is persistent neural firing which is believed to serve short-term (hundreds of milliseconds up to tens of seconds) maintenance of necessary information. In this review, we will focus on the role of transient receptor potential canonical (TRPC) channels as a mechanism underlying persistent firing. Many years of in vitro work have been suggesting a crucial role of TRPC channels in working memory and temporal association tasks. If TRPC channels are indeed a central mechanism for working memory, manipulations which impair or facilitate working memory should have a similar effect on TRPC channel modulation. However, modulations of working memory and TRPC channels were never systematically compared, and it remains unanswered whether TRPC channels indeed contribute to working memory in vivo or not. In this article, we review the effects of G-protein coupled receptors (GPCR) and neuromodulators, including acetylcholine, noradrenalin, serotonin and dopamine, on working memory and TRPC channels. Based on comparisons, we argue that GPCR and downstream signaling pathways that activate TRPC, generally support working memory, while those that suppress TRPC channels impair it. However, depending on the channel types, areas, and systems tested, this is not the case in all studies. Further work to clarify involvement of specific TRPC channels in working memory tasks and how they are affected by neuromodulators is still necessary in the future.
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Affiliation(s)
- Antonio Reboreda
- Leibniz Institute for Neurobiology (LIN) Magdeburg, Brenneckestraße 6, 39118 Magdeburg, Germany; German Center for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str. 44/Haus 64, 39120, Magdeburg, Germany.
| | - Frederik M Theissen
- German Center for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str. 44/Haus 64, 39120, Magdeburg, Germany
| | - Maria J Valero-Aracama
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstraße 17, 91054 Erlangen, Germany
| | - Alberto Arboit
- German Center for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str. 44/Haus 64, 39120, Magdeburg, Germany
| | - Mihaela A Corbu
- Ruhr University Bochum (RUB), Universitätsstraße 150, 44801, Bochum, Germany
| | - Motoharu Yoshida
- Leibniz Institute for Neurobiology (LIN) Magdeburg, Brenneckestraße 6, 39118 Magdeburg, Germany; German Center for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str. 44/Haus 64, 39120, Magdeburg, Germany; Center for Behavioral Brain Sciences, 39106, Magdeburg, Germany.
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21
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Abstract
Accumulating evidence suggest that TRPC channels play critical roles in various aspects of epileptogenesis. TRPC1/4 channels are major contributors to nonsynaptically derived epileptiform burst firing in the CA1 and the lateral septum. TRPC7 channels play a critical role in synaptically derived epileptiform burst firing. The reduction of spontaneous epileptiform bursting in the CA3 is correlated to a reduction in pilocarpine-induced SE in vivo in TRPC7 knockout mice. TRPC channels are also significant contributors to SE-induced neuronal cell death. Although the pilocarpine-induced SE itself is not significantly reduced, the SE-induced neuronal cell death is significantly reduced in the CA1 and the lateral septum, indicating that TRPC1/4 channels directly contribute to SE-induced neuronal cell death. Genetic ablation of TRPC5 also reduces SE-induced neuronal cell death in the CA1 and CA3 areas of the hippocampus.
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22
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Bavencoffe A, Zhu MX, Tian JB. New Aspects of the Contribution of ER to SOCE Regulation: TRPC Proteins as a Link Between Plasma Membrane Ion Transport and Intracellular Ca2+ Stores. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:239-255. [DOI: 10.1007/978-3-319-57732-6_13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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23
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Sukumaran P, Sun Y, Schaar A, Selvaraj S, Singh BB. TRPC Channels and Parkinson's Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 976:85-94. [PMID: 28508315 DOI: 10.1007/978-94-024-1088-4_8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder, which involves degeneration of dopaminergic neurons that are present in the substantia nigra pars compacta (SNpc) region. Many factors have been identified that could lead to Parkinson's disease; however, almost all of them are directly or indirectly dependent on Ca2+ signaling. Importantly, though disturbances in Ca2+ homeostasis have been implicated in Parkinson's disease and other neuronal diseases, the identity of the calcium channel remains elusive. Members of the transient receptor potential canonical (TRPC) channel family have been identified as a new class of Ca2+ channels, and it could be anticipated that these channels could play important roles in neurodegenerative diseases, especially in PD. Thus, in this chapter we have entirely focused on TRPC channels and elucidated its role in PD.
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Affiliation(s)
- Pramod Sukumaran
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Yuyang Sun
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Anne Schaar
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Senthil Selvaraj
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Brij B Singh
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA.
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Phelan KD, Shwe UT, Cozart MA, Wu H, Mock MM, Abramowitz J, Birnbaumer L, Zheng F. TRPC3 channels play a critical role in the theta component of pilocarpine-induced status epilepticus in mice. Epilepsia 2016; 58:247-254. [PMID: 28012173 DOI: 10.1111/epi.13648] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Canonical transient receptor potential (TRPC) channels constitute a family of cation channels that exhibit a regional and cell-specific expression pattern throughout the brain. It has been reported previously that TRPC3 channels are effectors of the brain-derived neurotrophic factor (BDNF)/trkB signaling pathway. Given the long postulated role of BDNF in epileptogenesis, TRPC3 channels may be a critical component in the underlying pathophysiology of seizure and epilepsy. In this study, we investigated the precise role of TRPC3 channels in pilocarpine-induced status epilepticus (SE). METHODS The role of TRPC3 channels was investigated using TRPC3 knockout (KO) mice and TRPC3-selective inhibitor Pyr3. Video and electroencephalography (EEG) recording of pilocarpine-induced seizures were performed. RESULTS We found that genetic ablation of TRPC3 channels reduces behavioral manifestations of seizures and the root-mean-square (RMS) power of SE, indicating a significant contribution of TRPC3 channels to pilocarpine-induced SE. Furthermore, the reduction in SE in TRPC3KO mice is caused by a selective attenuation of pilocarpine-induced theta activity, which dominates both the preictal phase and SE phase. Pyr3 also caused a reduction in the overall RMS power of pilocarpine-induced SE and a selective reduction in the theta activity during SE. SIGNIFICANCE Our results demonstrate that TRPC3 channels unequivocally contribute to pilocarpine-induced SE and could be a novel molecular target for new anticonvulsive drugs.
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Affiliation(s)
- Kevin D Phelan
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - U Thaung Shwe
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - Michael A Cozart
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - Hong Wu
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - Matthew M Mock
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - Joel Abramowitz
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina, U.S.A
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina, U.S.A.,Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Fang Zheng
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
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Chen X, Li W, Riley AM, Soliman M, Chakraborty S, Stamatkin CW, Obukhov AG. Molecular Determinants of the Sensitivity to Gq/11-Phospholipase C-dependent Gating, Gd3+ Potentiation, and Ca2+ Permeability in the Transient Receptor Potential Canonical Type 5 (TRPC5) Channel. J Biol Chem 2016; 292:898-911. [PMID: 27920205 DOI: 10.1074/jbc.m116.755470] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/24/2016] [Indexed: 11/06/2022] Open
Abstract
Transient receptor potential canonical type 5 (TRPC5) is a Ca2+-permeable cation channel that is highly expressed in the brain and is implicated in motor coordination, innate fear behavior, and seizure genesis. The channel is activated by a signal downstream of the G-protein-coupled receptor (GPCR)-Gq/11-phospholipase C (PLC) pathway. In this study we aimed to identify the molecular mechanisms involved in regulating TRPC5 activity. We report that Arg-593, a residue located in the E4 loop near the TRPC5 extracellular Gd3+ binding site, is critical for conferring the sensitivity to GPCR-Gq/11-PLC-dependent gating on TRPC5. Indeed, guanosine 5'-O-(thiotriphosphate) and GPCR agonists only weakly activate the TRPC5R593A mutant, whereas the addition of Gd3+ rescues the mutant's sensitivity to GPCR-Gq/11-PLC-dependent gating. Computer modeling suggests that Arg-593 may cross-bridge the E3 and E4 loops, forming the "molecular fulcrum." While validating the model using site-directed mutagenesis, we found that the Tyr-542 residue is critical for establishing a functional Gd3+ binding site, the Tyr-541 residue participates in fine-tuning Gd3+-sensitivity, and that the Asn-584 residue determines Ca2+ permeability of the TRPC5 channel. This is the first report providing molecular insights into the molecular mechanisms regulating the sensitivity to GPCR-Gq/11-PLC-dependent gating of a receptor-operated channel.
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Affiliation(s)
- Xingjuan Chen
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Wennan Li
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Ashley M Riley
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Mario Soliman
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Saikat Chakraborty
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Christopher W Stamatkin
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Alexander G Obukhov
- From the Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
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Zheng DH, Guo W, Sun FJ, Xu GZ, Zang ZL, Shu HF, Yang H. Expression of TRPC6 and BDNF in Cortical Lesions From Patients With Focal Cortical Dysplasia. J Neuropathol Exp Neurol 2016; 75:718-730. [PMID: 27288906 PMCID: PMC4940447 DOI: 10.1093/jnen/nlw044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Indexed: 01/15/2023] Open
Abstract
Focal cortical dysplasia (FCD) likely results from abnormal migration of neural progenitor cells originating from the subventricular zone. To elucidate the roles in molecules that are involved in neural migration pathway abnormalities in FCDs, we investigated the expression patterns of transient receptor potential canonical channel 6 (TRPC6) and brain-derived neurotrophic factor (BDNF) in cortical lesions from FCD patients and in samples of normal control cortex. TRPC6 and BDNF mRNA and protein levels were increased in FCD lesions. By immunohistochemistry, they were strongly expressed in microcolumns, heterotopic neurons, dysmorphic neurons, and balloon cells (BCs). Colocalization assays revealed that most of the misshapen TRPC6-positive or heterotopic cells had a neuronal lineage with the exception of TRPC6-positive FCDiib patient BCs, which had both neuronal and glial features. Most TRPC6-positive cells were glutamatergic neurons. There was also greater expression of calmodulin-dependent kinase IV (CaMKIV), the downstream factor of TRPC6, in FCD lesions, suggesting that TRPC6 expression promoted dendritic growth and the development of dendritic spines and excitatory synapses via the CaMKIV-CREB pathway in FCD. Thus, overexpression of BDNF and TRPC6 and activation of the TRPC6 signal transduction pathway in cortical lesions of FCD patients may contribute to FC pathogenesis and epileptogenesis.
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Affiliation(s)
- Da-Hai Zheng
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China
| | - Wei Guo
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China
| | - Fei-Ji Sun
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China
| | - Guang-Zhen Xu
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China
| | - Zhen-Le Zang
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China
| | - Hai-Feng Shu
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China
| | - Hui Yang
- From the Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University (D-HZ, F-J, G-ZX, Z-LZ, H-FS, HY), Chongqing, China; Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University(WG), Xi'an, Shanxi, China; Department of Neurosurgery, General Hospital of Chengdu Military Region(H-FS), Chengdu, Sichuan, China.
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Transient Receptor Potential Canonical 7 (TRPC7), a Calcium (Ca(2+)) Permeable Non-selective Cation Channel. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:251-64. [PMID: 27161232 DOI: 10.1007/978-3-319-26974-0_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transient receptor potential canonical subfamily, member 7 (TRPC7) is the most recently identified member of the TRPC family of Ca(2+)-permeable non-selective cation channels. The gene encoding the TRPC7 channel plasma membrane protein was first cloned from mouse brain. TRPC7 mRNA and protein have been detected in cell types derived from multiple organ systems from various species including humans. Gq-coupled protein receptor activation is the predominant mode of TRPC7 activation. Lipid metabolites involved in the phospholipase C (PLC) signaling pathway, including diacylglycerol (DAG) and its precursor the phosphatidylinositol-4,5-bisphosphate (PIP2), have been shown to be direct regulators of TRPC7 channel. TRPC7 channels have been linked to the regulation of various cellular functions however, the depth of our understanding of TRPC7 channel function and regulation is limited in comparison to other TRP channel family members. This review takes a historical look at our current knowledge of TRPC7 mechanisms of activation and its role in cellular physiology and pathophysiology.
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From GTP and G proteins to TRPC channels: a personal account. J Mol Med (Berl) 2015; 93:941-53. [PMID: 26377676 DOI: 10.1007/s00109-015-1328-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/28/2015] [Indexed: 10/23/2022]
Abstract
By serendipity and good fortune, as a postdoctoral fellow in 1967, I landed at the right place at the right time, as I was allowed to investigate the mechanism by which hormones activate the enzyme adenylyl cyclase (then adenyl cyclase) in Martin Rodbell's Laboratory at the NIH in Bethesda, Maryland. The work uncovered first, the existence of receptors separate from the enzyme and then, the existence of transduction mechanisms requiring guanosine-5'-triphosphate (GTP) and Mg(2+). With my laboratory colleagues first and postdoctoral fellows after leaving NIH, I participated in the development of the field "signal transduction by G proteins," uncovered by molecular cloning several G-protein-coupled receptors (GPCRs) and became interested in both the molecular makeup of voltage-gated Ca channels and Ca2+ homeostasis downstream of activation of phospholipase C (PLC) by the Gq/11 signaling pathway. We were able to confirm the hypothesis that there would be mammalian homologues of the Drosophila "transient receptor potential" channel and discovered the existence of six of the seven mammalian genes, now called transient receptor potential canonical (TRPC) channels. In the present article, I summarize from a bird's eye view of what I feel were key findings along this path, not only from my laboratory but also from many others, that allowed for the present knowledge of cell signaling involving G proteins to evolve. Towards the end, I summarize roles of TRPC channels in health and disease.
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Phelan KD, Shwe UT, Williams DK, Greenfield LJ, Zheng F. Pilocarpine-induced status epilepticus in mice: A comparison of spectral analysis of electroencephalogram and behavioral grading using the Racine scale. Epilepsy Res 2015; 117:90-6. [PMID: 26432759 DOI: 10.1016/j.eplepsyres.2015.09.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 08/20/2015] [Accepted: 09/10/2015] [Indexed: 11/30/2022]
Abstract
Pilocarpine-induced status epilepticus (SE) is a widely used seizure model in mice, and the Racine scale has been used to index seizure intensity. The goal of this study was to analyze electroencephalogram (EEG) quantitatively using fast Fourier transformation (FFT) and statistically evaluate the correlation of electrographic seizures with convulsive behaviors. Simultaneous EEG and video recordings in male mice in a mixed genetic background were conducted and pilocarpine was administered intraperitoneally to induce seizures. The videos were graded using the Racine scale and the root-mean-square (RMS) power analysis of EEG was performed with Sirenia Seizure Pro software. We found that the RMS power was very weakly correlated with convulsive behavior induced by pilocarpine. Convulsive behaviors appeared long before electrographic seizures and showed a strong negative correlation with theta frequency activity and a moderate positive correlation with gamma frequency activity. Racine scores showed moderate correlations with RMS power across multiple frequency bands during the transition from first electrographic seizure to SE. However, there was no correlation between Racine scores and RMS power during the SE phase except a weak correlation with RMS power in the theta frequency. Our analysis reveals limitations of the Racine scale as a primary index of seizure intensity in status epilepticus, and demonstrates a need for quantitative analysis of EEG for an accurate assessment of seizure onset and severity.
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Affiliation(s)
- Kevin D Phelan
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 West Markham St, Slot 846, Little Rock, AR 72205, United States
| | - U T Shwe
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham St, Slot 611, Little Rock, AR 72205, United States
| | - David K Williams
- Department of Biostatistics, University of Arkansas for Medical Sciences, 4301 West Markham St, Slot 781, Little Rock, AR 72205, United States
| | - L John Greenfield
- Department of Neurology, University of Arkansas for Medical Sciences, 4301 West Markham St, Slot 841, Little Rock, AR 72205, United States
| | - Fang Zheng
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham St, Slot 611, Little Rock, AR 72205, United States.
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Zeng C, Tian F, Xiao B. TRPC Channels: Prominent Candidates of Underlying Mechanism in Neuropsychiatric Diseases. Mol Neurobiol 2014; 53:631-647. [DOI: 10.1007/s12035-014-9004-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 11/13/2014] [Indexed: 10/24/2022]
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Yi F, DeCan E, Stoll K, Marceau E, Deisseroth K, Lawrence JJ. Muscarinic excitation of parvalbumin-positive interneurons contributes to the severity of pilocarpine-induced seizures. Epilepsia 2014; 56:297-309. [PMID: 25495999 DOI: 10.1111/epi.12883] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2014] [Indexed: 01/20/2023]
Abstract
OBJECTIVE A common rodent model in epilepsy research employs the muscarinic acetylcholine receptor (mAChR) agonist pilocarpine, yet the mechanisms underlying the induction of pilocarpine-induced seizures (PISs) remain unclear. Global M1 mAChR (M1 R) knockout mice are resistant to PISs, implying that M1 R activation disrupts excitation/inhibition balance. Parvalbumin-positive (PV) inhibitory neurons express M1 Rs, participate in cholinergically induced oscillations, and can enter a state of depolarization block (DB) during epileptiform activity. Here, we test the hypothesis that pilocarpine activation of M1 Rs expressed on PV cells contributes to PISs. METHODS CA1 PV cells in PV-CRE mice were visualized with a floxed YFP or hM3Dq-mCherry adeno-associated virus, or by crossing PV-CRE mice with the RosaYFP reporter line. To eliminate M1 Rs from PV cells, we generated PV-M1 knockout (KO) mice by crossing PV-CRE and floxed M1 mice. Action potential (AP) frequency was monitored during application of pilocarpine (200 μm). In behavioral experiments, locomotion and seizure symptoms were recorded in wild-type (WT) or PV-M1 KO mice during PISs. RESULTS Pilocarpine significantly increased AP frequency in CA1 PV cells into the gamma range. In the continued presence of pilocarpine, a subset (5/7) of PV cells progressed to DB, which was mimicked by hM3Dq activation of Gq-receptor signaling. Pilocarpine-induced depolarization, AP firing at gamma frequency, and progression to DB were prevented in CA1 PV cells of PV-M1 KO mice. Finally, compared to WT mice, PV-M1 KO mice were associated with reduced severity of PISs. SIGNIFICANCE Pilocarpine can directly depolarize PV+ cells via M1 R activation, but a subset of these cells progress to DB. Our electrophysiologic and behavioral results suggest that this mechanism is active during PISs, contributing to a collapse of PV-mediated γ-aminobutyric acid (GABA)ergic inhibition, dysregulation of excitation/inhibition balance, and increased susceptibility to PISs.
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Affiliation(s)
- Feng Yi
- COBRE Center for Structural and Functional Neuroscience, The University of Montana, Missoula, Montana, U.S.A; Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana, U.S.A
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