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Lin TK, Hung CF, Weng JR, Hsieh TY, Wang SJ. Kaempferol 3-Rhamnoside on Glutamate Release from Rat Cerebrocortical Nerve Terminals Involves P/Q-Type Ca 2+ Channel and Ca 2+/Calmodulin-Dependent Protein Kinase II-Dependent Pathway Suppression. Molecules 2022; 27:molecules27041342. [PMID: 35209129 PMCID: PMC8879690 DOI: 10.3390/molecules27041342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/12/2022] [Accepted: 02/14/2022] [Indexed: 11/22/2022]
Abstract
Excess synaptic glutamate release has pathological consequences, and the inhibition of glutamate release is crucial for neuroprotection. Kaempferol 3-rhamnoside (KR) is a flavonoid isolated from Schima superba with neuroprotective properties, and its effecton the release of glutamate from rat cerebrocortical nerve terminals was investigated. KR produced a concentration-dependent inhibition of 4-aminopyridine (4-AP)-evoked glutamate release with half-maximal inhibitory concentration value of 17 µM. The inhibition of glutamate release by KR was completely abolished by the omission of external Ca2+ or the depletion of glutamate in synaptic vesicles, and it was unaffected by blocking carrier-mediated release. In addition, KR reduced the 4-AP-evoked increase in Ca2+ concentration, while it did not affect 4-AP-evoked membrane potential depolarization. The application of selective antagonists of voltage-dependent Ca2+ channels revealed that the KR-mediated inhibition of glutamate release involved the suppression of P/Q-type Ca2+ channel activity. Furthermore, the inhibition of release was abolished by the calmodulin antagonist, W7, and Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor, KN62, but not by the protein kinase A (PKA) inhibitor, H89, or the protein kinase C (PKC) inhibitor, GF109203X. We also found that KR reduced the 4-AP-induced increase in phosphorylation of CaMKII and its substrate synapsin I. Thus, the effect of KR on evoked glutamate release is likely linked to a decrease in P/Q-type Ca2+ channel activity, as well as to the consequent reduction in the CaMKII/synapsin I pathway.
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Affiliation(s)
- Tzu-Kang Lin
- Department of Neurosurgery, Fu Jen Catholic University Hospital, Fu Jen Catholic University, New Taipei City 24205, Taiwan;
- School of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan;
| | - Chi-Feng Hung
- School of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan;
| | - Jing-Ru Weng
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan;
| | - Ting-Yang Hsieh
- P.H.D. Program in Nutrition & Food Science, Fu Jen Catholic University, New Taipei City 24205, Taiwan;
| | - Su-Jane Wang
- School of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan;
- Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan
- Correspondence: ; Tel.: +886-2-2905-3465; Fax: +886-2-2905-2096
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Jaudon F, Baldassari S, Musante I, Thalhammer A, Zara F, Cingolani LA. Targeting Alternative Splicing as a Potential Therapy for Episodic Ataxia Type 2. Biomedicines 2020; 8:E332. [PMID: 32899500 PMCID: PMC7555146 DOI: 10.3390/biomedicines8090332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 12/26/2022] Open
Abstract
Episodic ataxia type 2 (EA2) is an autosomal dominant neurological disorder characterized by paroxysmal attacks of ataxia, vertigo, and nausea that usually last hours to days. It is caused by loss-of-function mutations in CACNA1A, the gene encoding the pore-forming α1 subunit of P/Q-type voltage-gated Ca2+ channels. Although pharmacological treatments, such as acetazolamide and 4-aminopyridine, exist for EA2, they do not reduce or control the symptoms in all patients. CACNA1A is heavily spliced and some of the identified EA2 mutations are predicted to disrupt selective isoforms of this gene. Modulating splicing of CACNA1A may therefore represent a promising new strategy to develop improved EA2 therapies. Because RNA splicing is dysregulated in many other genetic diseases, several tools, such as antisense oligonucleotides, trans-splicing, and CRISPR-based strategies, have been developed for medical purposes. Here, we review splicing-based strategies used for genetic disorders, including those for Duchenne muscular dystrophy, spinal muscular dystrophy, and frontotemporal dementia with Parkinsonism linked to chromosome 17, and discuss their potential applicability to EA2.
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Affiliation(s)
- Fanny Jaudon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy;
| | - Simona Baldassari
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
| | - Ilaria Musante
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16126 Genoa, Italy
| | - Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy;
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16126 Genoa, Italy
| | - Lorenzo A. Cingolani
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy;
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy;
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Thalhammer A, Jaudon F, Cingolani LA. Emerging Roles of Activity-Dependent Alternative Splicing in Homeostatic Plasticity. Front Cell Neurosci 2020; 14:104. [PMID: 32477067 PMCID: PMC7235277 DOI: 10.3389/fncel.2020.00104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022] Open
Abstract
Homeostatic plasticity refers to the ability of neuronal networks to stabilize their activity in the face of external perturbations. Most forms of homeostatic plasticity ultimately depend on changes in the expression or activity of ion channels and synaptic proteins, which may occur at the gene, transcript, or protein level. The most extensively investigated homeostatic mechanisms entail adaptations in protein function or localization following activity-dependent posttranslational modifications. Numerous studies have also highlighted how homeostatic plasticity can be achieved by adjusting local protein translation at synapses or transcription of specific genes in the nucleus. In comparison, little attention has been devoted to whether and how alternative splicing (AS) of pre-mRNAs underlies some forms of homeostatic plasticity. AS not only expands proteome diversity but also contributes to the spatiotemporal dynamics of mRNA transcripts. Prominent in the brain where it can be regulated by neuronal activity, it is a flexible process, tightly controlled by a multitude of factors. Given its extensive use and versatility in optimizing the function of ion channels and synaptic proteins, we argue that AS is ideally suited to achieve homeostatic control of neuronal output. We support this thesis by reviewing emerging evidence linking AS to various forms of homeostatic plasticity: homeostatic intrinsic plasticity, synaptic scaling, and presynaptic homeostatic plasticity. Further, we highlight the relevance of this connection for brain pathologies.
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Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,Department of Life Sciences, University of Trieste, Trieste, Italy
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Abstract
Small-conductance Ca2+-activated K+ (SK) and large-conductance voltage- and Ca2+-activated K+ (BK) channels are Ca2+-activated K+ channels that control action potential firing in diverse neurons in the brain. In cartwheel cells of the dorsal cochlear nucleus, blockade of either channel type leads to excessive production of spike bursts. In the same cells, P/Q-type Ca2+ channels in plasma membrane and ryanodine receptors in endoplasmic reticulum supply Ca2+ to BK channels through Ca2+ nanodomain signaling. In this study, voltage-clamp experiments were performed in cartwheel cells in mouse brain slices to examine the Ca2+ signaling pathways underlying activation of SK channels. As with BK channels, SK channels required the activity of P/Q-type Ca2+ channels. However, this signaling occurred across Ca2+ micro- rather than nanodomain distances and was independent of Ca2+ release from endoplasmic reticulum. These differential modes of activation may lead to distinct time courses of the two K+ currents and therefore control excitability of auditory neurons across different timescales.NEW & NOTEWORTHY This study has shown for the first time that in cartwheel cells of the dorsal cochlear nucleus, small-conductance Ca2+-activated K+ (SK) channels were triggered by the activation of P/Q-type Ca2+ channels in which SK-P/Q-type coupling is mediated within the Ca2+ microdomains (loose coupling). Although Ca2+-induced Ca2+ release is able to activate large-conductance voltage- and Ca2+-activated K+ (BK) channels in cartwheel cells, it did not contribute to SK activation.
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Affiliation(s)
- Tomohiko Irie
- Division of Pharmacology, National Institute of Health Sciences, Kawasaki City, Kanagawa, Japan
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De Pascual R, Colmena I, Ruiz-Pascual L, Baraibar AM, Egea J, Gandía L, García AG. Regulation by L channels of Ca(2+)-evoked secretory responses in ouabain-treated chromaffin cells. Pflugers Arch 2016; 468:1779-92. [PMID: 27558258 DOI: 10.1007/s00424-016-1866-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/21/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
It is known that the sustained depolarisation of adrenal medullary bovine chromaffin cells (BCCs) with high K(+) concentrations produces an initial sharp catecholamine release that subsequently fades off in spite depolarisation persists. Here, we have recreated a sustained depolarisation condition of BCCs by treating them with the Na(+)/K(+) ATPase blocker ouabain; in doing so, we searched experimental conditions that permitted the development of a sustained long-term catecholamine release response that could be relevant during prolonged stress. BCCs were perifused with nominal 0Ca(2+) solution, and secretion responses were elicited by intermittent application of short 2Ca(2+) pulses (Krebs-HEPES containing 2 mM Ca(2+)). These pulses elicited a biphasic secretory pattern with an initial 30-min period with secretory responses of increasing amplitude and a second 30-min period with steady-state, non-inactivating responses. The initial phase was not due to gradual depolarisation neither to gradual increases of the cytosolic calcium transients ([Ca(2+)]c) elicited by 2Ca(2+) pulses in BBCs exposed to ouabain; both parameters increased soon after ouabain addition. Νifedipine blocked these responses, and FPL64176 potentiated them, suggesting that they were triggered by Ca(2+) entry through non-inactivating L-type calcium channels. This was corroborated by nifedipine-evoked blockade of the L-type Ca(2+) channel current and the [Ca(2+)]c transients elicited by 2Ca(2+) pulses. Furthermore, the plasmalemmal Na(+)/Ca(2+) exchanger (NCX) blocker SEA0400 caused a mild inhibition followed by a large rebound increase of the steady-state secretory responses. We conclude that these two phases of secretion are mostly contributed by Ca(2+) entry through L calcium channels, with a minor contribution of Ca(2+) entry through the reverse mode of the NCX.
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Xu J, Chu KL, Zhu CZ, Niforatos W, Swensen A, Searle X, Lee L, Jarvis MF, McGaraughty S. A mixed Ca2+ channel blocker, A-1264087, utilizes peripheral and spinal mechanisms to inhibit spinal nociceptive transmission in a rat model of neuropathic pain. J Neurophysiol 2013; 111:394-404. [PMID: 24155005 DOI: 10.1152/jn.00463.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-, T- and P/Q-type voltage-gated Ca(2+) channels are critical for regulating neurotransmitter release and cellular excitability and have been implicated in mediating pathological nociception. A-1264087 is a novel state-dependent blocker of N-, T- and P/Q-type channels. In the present studies, A-1264087 blocked (IC50 = 1.6 μM) rat dorsal root ganglia N-type Ca(2+) in a state-dependent fashion. A-1264087 (1, 3 and 10 mg/kg po) dose-dependently reduced mechanical allodynia in rats with a spinal nerve ligation (SNL) injury. A-1264087 (4 mg/kg iv) inhibited both spontaneous and mechanically evoked activity of spinal wide dynamic range (WDR) neurons in SNL rats but had no effect in uninjured rats. The inhibitory effect on WDR neurons remained in spinally transected SNL rats. Injection of A-1264087 (10 nmol/0.5 μl) into the spinal cord reduced both spontaneous and evoked WDR activity in SNL rats. Application of A-1264087 (300 nmol/20 μl) into the receptive field on the hindpaw attenuated evoked but not spontaneous firing of WDR neurons. Using electrical stimulation, A-1264087 (4 mg/kg iv) inhibited Aδ- and C-fiber evoked responses and after-discharge of WDR neurons in SNL rats. These effects by A-1264087 were not present in uninjured rats. A-1264087 moderately attenuated WDR neuron windup in both uninjured and SNL rats. In summary, these results indicate that A-1264087 selectively inhibited spinal nociceptive transmission in sensitized states through both peripheral and central mechanisms.
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Affiliation(s)
- Jun Xu
- Neuroscience Research, AbbVie, North Chicago, Illinos
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