1
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Filippini L, Ortner NJ, Kaserer T, Striessnig J. Ca v 1.3-selective inhibitors of voltage-gated L-type Ca 2+ channels: Fact or (still) fiction? Br J Pharmacol 2023; 180:1289-1303. [PMID: 36788128 PMCID: PMC10953394 DOI: 10.1111/bph.16060] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/17/2022] [Accepted: 01/29/2023] [Indexed: 02/16/2023] Open
Abstract
Voltage-gated L-type Ca2+ -channels (LTCCs) are the target of Ca2+ -channel blockers (CCBs), which are in clinical use for the evidence-based treatment of hypertension and angina. Their cardiovascular effects are largely mediated by the Cav 1.2-subtype. However, based on our current understanding of their physiological and pathophysiological roles, Cav 1.3 LTCCs also appear as attractive drug targets for the therapy of various diseases, including treatment-resistant hypertension, spasticity after spinal cord injury and neuroprotection in Parkinson's disease. Since CCBs inhibit both Cav 1.2 and Cav 1.3, Cav 1.3-selective inhibitors would be valuable tools to validate the therapeutic potential of Cav 1.3 channel inhibition in preclinical models. Despite a number of publications reporting the discovery of Cav 1.3-selective blockers, their selectivity remains controversial. We conclude that at present no pharmacological tools exist that are suitable to confirm or refute a role of Cav 1.3 channels in cellular responses. We also suggest essential criteria for a small molecule to be considered Cav 1.3-selective.
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Affiliation(s)
- Ludovica Filippini
- Department of Pharmacology and Toxicology and Center of Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
- Department of Pharmaceutical Chemistry, Institute of PharmacyUniversity of InnsbruckInnsbruckAustria
| | - Nadine J. Ortner
- Department of Pharmacology and Toxicology and Center of Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | - Teresa Kaserer
- Department of Pharmaceutical Chemistry, Institute of PharmacyUniversity of InnsbruckInnsbruckAustria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology and Center of Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
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2
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CaV1.3 enhanced store operated calcium promotes resistance to androgen deprivation in prostate cancer. Cell Calcium 2022; 103:102554. [DOI: 10.1016/j.ceca.2022.102554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/24/2022] [Accepted: 02/06/2022] [Indexed: 01/01/2023]
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3
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Hofer NT, Pinggera A, Nikonishyna YV, Tuluc P, Fritz EM, Obermair GJ, Striessnig J. Stabilization of negative activation voltages of Cav1.3 L-Type Ca 2+-channels by alternative splicing. Channels (Austin) 2021; 15:38-52. [PMID: 33380256 PMCID: PMC7781618 DOI: 10.1080/19336950.2020.1859260] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 11/30/2022] Open
Abstract
-->Low voltage-activated Cav1.3 L-type Ca2+-channels are key regulators of neuronal excitability controlling neuronal development and different types of learning and memory. Their physiological functions are enabled by their negative activation voltage-range, which allows Cav1.3 to be active at subthreshold voltages. Alternative splicing in the C-terminus of their pore-forming α1-subunits gives rise to C-terminal long (Cav1.3L) and short (Cav1.3S) splice variants allowing Cav1.3S to activate at even more negative voltages than Cav1.3L. We discovered that inclusion of exons 8b, 11, and 32 in Cav1.3S further shifts activation (-3 to -4 mV) and inactivation (-4 to -6 mV) to more negative voltages as revealed by functional characterization in tsA-201 cells. We found transcripts of these exons in mouse chromaffin cells, the cochlea, and the brain. Our data further suggest that Cav1.3-containing exons 11 and 32 constitute a significant part of native channels in the brain. We therefore investigated the effect of these splice variants on human disease variants. Splicing did not prevent the gating defects of the previously reported human pathogenic variant S652L, which further shifted the voltage-dependence of activation of exon 11-containing channels by more than -12 mV. In contrast, we found no evidence for gating changes of the CACNA1D missense variant R498L, located in exon 11, which has recently been identified in a patient with an epileptic syndrome. Our data demonstrate that alternative splicing outside the C-terminus involving exons 11 and 32 contributes to channel fine-tuning by stabilizing negative activation and inactivation gating properties of wild-type and mutant Cav1.3 channels.
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Affiliation(s)
- Nadja T. Hofer
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Austria
| | - Alexandra Pinggera
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Yuliia V. Nikonishyna
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Austria
| | - Eva M. Fritz
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Austria
| | - Gerald J. Obermair
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Centre for Molecular Biosciences, University of Innsbruck, Austria
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4
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Little HJ. L-Type Calcium Channel Blockers: A Potential Novel Therapeutic Approach to Drug Dependence. Pharmacol Rev 2021; 73:127-154. [PMID: 34663686 DOI: 10.1124/pharmrev.120.000245] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review describes interactions between compounds, primarily dihydropyridines, that block L-type calcium channels and drugs that cause dependence, and the potential importance of these interactions. The main dependence-inducing drugs covered are alcohol, psychostimulants, opioids, and nicotine. In preclinical studies, L-type calcium channel blockers prevent or reduce important components of dependence on these drugs, particularly their reinforcing actions and the withdrawal syndromes. The channel blockers also reduce the development of tolerance and/or sensitization, and they have no intrinsic dependence liability. In some instances, their effects include reversal of brain changes established during drug dependence. Prolonged treatment with alcohol, opioids, psychostimulant drugs, or nicotine causes upregulation of dihydropyridine binding sites. Few clinical studies have been carried out so far, and reports are conflicting, although there is some evidence of effectiveness of L-channel blockers in opioid withdrawal. However, the doses of L-type channel blockers used clinically so far have necessarily been limited by potential cardiovascular problems and may not have provided sufficient central levels of the drugs to affect neuronal dihydropyridine binding sites. New L-type calcium channel blocking compounds are being developed with more selective actions on subtypes of L-channel. The preclinical evidence suggests that L-type calcium channels may play a crucial role in the development of dependence to different types of drugs. Mechanisms for this are proposed, including changes in the activity of mesolimbic dopamine neurons, genomic effects, and alterations in synaptic plasticity. Newly developed, more selective L-type calcium channel blockers could be of considerable value in the treatment of drug dependence. SIGNIFICANCE STATEMENT: Dependence on drugs is a very serious health problem with little effective treatment. Preclinical evidence shows drugs that block particular calcium channels, the L-type, reduce dependence-related effects of alcohol, opioids, psychostimulants, and nicotine. Clinical studies have been restricted by potential cardiovascular side effects, but new, more selective L-channel blockers are becoming available. L-channel blockers have no intrinsic dependence liability, and laboratory evidence suggests they reverse previously developed effects of dependence-inducing drugs. They could provide a novel approach to addiction treatment.
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Affiliation(s)
- Hilary J Little
- Section of Alcohol Research, National Addiction Centre, Institute of Psychiatry, King's College, London, United Kingdom
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5
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Koschak A, Fernandez-Quintero ML, Heigl T, Ruzza M, Seitter H, Zanetti L. Cav1.4 dysfunction and congenital stationary night blindness type 2. Pflugers Arch 2021; 473:1437-1454. [PMID: 34212239 PMCID: PMC8370969 DOI: 10.1007/s00424-021-02570-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/14/2021] [Accepted: 04/18/2021] [Indexed: 12/04/2022]
Abstract
Cav1.4 L-type Ca2+ channels are predominantly expressed in retinal neurons, particularly at the photoreceptor terminals where they mediate sustained Ca2+ entry needed for continuous neurotransmitter release at their ribbon synapses. Cav1.4 channel gating properties are controlled by accessory subunits, associated regulatory proteins, and also alternative splicing. In humans, mutations in the CACNA1F gene encoding for Cav1.4 channels are associated with X-linked retinal disorders such as congenital stationary night blindness type 2. Mutations in the Cav1.4 protein result in a spectrum of altered functional channel activity. Several mouse models broadened our understanding of the role of Cav1.4 channels not only as Ca2+ source at retinal synapses but also as synaptic organizers. In this review, we highlight different structural and functional phenotypes of Cav1.4 mutations that might also occur in patients with congenital stationary night blindness type 2. A further important yet mostly neglected aspect that we discuss is the influence of alternative splicing on channel dysfunction. We conclude that currently available functional phenotyping strategies should be refined and summarize potential specific therapeutic options for patients carrying Cav1.4 mutations. Importantly, the development of new therapeutic approaches will permit a deeper understanding of not only the disease pathophysiology but also the physiological function of Cav1.4 channels in the retina.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Calcium Channel Agonists/pharmacology
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Eye Diseases, Hereditary/genetics
- Eye Diseases, Hereditary/metabolism
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Humans
- Mutation/physiology
- Myopia/genetics
- Myopia/metabolism
- Night Blindness/genetics
- Night Blindness/metabolism
- Retina/drug effects
- Retina/metabolism
- Synapses/drug effects
- Synapses/genetics
- Synapses/metabolism
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Affiliation(s)
- Alexandra Koschak
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria.
| | - Monica L Fernandez-Quintero
- Institute of General, Inorganic and Theoretical Chemistry, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Thomas Heigl
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Marco Ruzza
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Hartwig Seitter
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Lucia Zanetti
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
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6
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Jiang MC, Birch DV, Heckman CJ, Tysseling VM. The Involvement of Ca V1.3 Channels in Prolonged Root Reflexes and Its Potential as a Therapeutic Target in Spinal Cord Injury. Front Neural Circuits 2021; 15:642111. [PMID: 33867945 PMCID: PMC8044857 DOI: 10.3389/fncir.2021.642111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/03/2021] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury (SCI) results in not only the loss of voluntary muscle control, but also in the presence of involuntary movement or spasms. These spasms post-SCI involve hyperexcitability in the spinal motor system. Hyperactive motor commands post SCI result from enhanced excitatory postsynaptic potentials (EPSPs) and persistent inward currents in voltage-gated L-type calcium channels (LTCCs), which are reflected in evoked root reflexes with different timings. To further understand the contributions of these cellular mechanisms and to explore the involvement of LTCC subtypes in SCI-induced hyperexcitability, we measured root reflexes with ventral root recordings and motoneuron activities with intracellular recordings in an in vitro preparation using a mouse model of chronic SCI (cSCI). Specifically, we explored the effects of 1-(3-chlorophenethyl)-3-cyclopentylpyrimidine-2,4,6-(1H,3H,5H)-trione (CPT), a selective negative allosteric modulator of CaV1.3 LTCCs. Our results suggest a hyperexcitability in the spinal motor system in these SCI mice. Bath application of CPT displayed slow onset but dose-dependent inhibition of the root reflexes with the strongest effect on LLRs. However, the inhibitory effect of CPT is less potent in cSCI mice than in acute SCI (aSCI) mice, suggesting changes either in composition of CaV1.3 or other cellular mechanisms in cSCI mice. For intracellular recordings, the intrinsic plateau potentials, was observed in more motoneurons in cSCI mice than in aSCI mice. CPT inhibited the plateau potentials and reduced motoneuron firings evoked by intracellular current injection. These results suggest that the LLR is an important target and that CPT has potential in the therapy of SCI-induced muscle spasms.
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Affiliation(s)
- Mingchen C Jiang
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Derin V Birch
- Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Charles J Heckman
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Vicki M Tysseling
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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7
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Ortner NJ. Voltage-Gated Ca 2+ Channels in Dopaminergic Substantia Nigra Neurons: Therapeutic Targets for Neuroprotection in Parkinson's Disease? Front Synaptic Neurosci 2021; 13:636103. [PMID: 33716705 PMCID: PMC7952618 DOI: 10.3389/fnsyn.2021.636103] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/25/2021] [Indexed: 12/21/2022] Open
Abstract
The loss of dopamine (DA)-producing neurons in the substantia nigra pars compacta (SN) underlies the core motor symptoms of the progressive movement disorder Parkinson's disease (PD). To date, no treatment to prevent or slow SN DA neurodegeneration exists; thus, the identification of the underlying factors contributing to the high vulnerability of these neurons represents the basis for the development of novel therapies. Disrupted Ca2+ homeostasis and mitochondrial dysfunction seem to be key players in the pathophysiology of PD. The autonomous pacemaker activity of SN DA neurons, in combination with low cytosolic Ca2+ buffering, leads to large somatodendritic fluctuations of intracellular Ca2+ levels that are linked to elevated mitochondrial oxidant stress. L-type voltage-gated Ca2+ channels (LTCCs) contribute to these Ca2+ oscillations in dendrites, and LTCC inhibition was beneficial in cellular and in vivo animal models of PD. However, in a recently completed phase 3 clinical trial, the dihydropyridine (DHP) LTCC inhibitor isradipine failed to slow disease progression in early PD patients, questioning the feasibility of DHPs for PD therapy. Novel evidence also suggests that R- and T-type Ca2+ channels (RTCCs and TTCCs, respectively) represent potential PD drug targets. This short review aims to (re)evaluate the therapeutic potential of LTCC, RTCC, and TTCC inhibition in light of novel preclinical and clinical data and the feasibility of available Ca2+ channel blockers to modify PD disease progression. I also summarize their cell-specific roles for SN DA neuron function and describe how their gating properties allow activity (and thus their contribution to stressful Ca2+ oscillations) during pacemaking.
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Affiliation(s)
- Nadine J. Ortner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
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8
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Protection of Cochlear Ribbon Synapses and Prevention of Hidden Hearing Loss. Neural Plast 2020; 2020:8815990. [PMID: 33204247 PMCID: PMC7652619 DOI: 10.1155/2020/8815990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 10/08/2020] [Accepted: 10/21/2020] [Indexed: 01/21/2023] Open
Abstract
In the auditory system, ribbon synapses are vesicle-associated structures located between inner hair cells (IHCs) and spiral ganglion neurons that are implicated in the modulation of trafficking and fusion of synaptic vesicles at the presynaptic terminals. Synapse loss may result in hearing loss and difficulties with understanding speech in a noisy environment. This phenomenon happens without permanent hearing loss; that is, the cochlear synaptopathy is "hidden." Recent studies have reported that synapse loss might be critical in the pathogenesis of hidden hearing loss. A better understanding of the molecular mechanisms of the formation, structure, regeneration, and protection of ribbon synapses will assist in the design of potential therapeutic strategies. In this review, we describe and summarize the following aspects of ribbon synapses: (1) functional and structural features, (2) potential mechanisms of damage, (3) therapeutic research on protecting the synapses, and (4) the role of synaptic regeneration in auditory neuropathy and the current options for synapse rehabilitation.
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9
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Cooper G, Kang S, Perez-Rosello T, Guzman JN, Galtieri D, Xie Z, Kondapalli J, Mordell J, Silverman RB, Surmeier DJ. A Single Amino Acid Determines the Selectivity and Efficacy of Selective Negative Allosteric Modulators of Ca V1.3 L-Type Calcium Channels. ACS Chem Biol 2020; 15:2539-2550. [PMID: 32881483 DOI: 10.1021/acschembio.0c00577] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ca2+ channels with a CaV1.3 pore-forming α1 subunit have been implicated in both neurodegenerative and neuropsychiatric disorders, motivating the development of selective and potent inhibitors of CaV1.3 versus CaV1.2 channels, the calcium channels implicated in hypertensive disorders. We have previously identified pyrimidine-2,4,6-triones (PYTs) that preferentially inhibit CaV1.3 channels, but the structural determinants of their interaction with the channel have not been identified, impeding their development into drugs. By a combination of biochemical, computational, and molecular biological approaches, it was found that PYTs bind to the dihydropyridine (DHP) binding pocket of the CaV1.3 subunit, establishing them as negative allosteric modulators of channel gating. Site-directed mutagenesis, based on homology models of CaV1.3 and CaV1.2 channels, revealed that a single amino acid residue within the DHP binding pocket (M1078) is responsible for the selectivity of PYTs for CaV1.3 over CaV1.2. In addition to providing direction for chemical optimization, these results suggest that, like dihydropyridines, PYTs have pharmacological features that could make them of broad clinical utility.
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Affiliation(s)
- Garry Cooper
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
- Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics, Northwestern University, Evanston, Illinois 60208, United States
| | - Soosung Kang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
- Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics, Northwestern University, Evanston, Illinois 60208, United States
- College of Pharmacy, Ewha Womans University, Seoul 03760, Korea
| | - Tamara Perez-Rosello
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - Jaime N. Guzman
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - Daniel Galtieri
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - Zhong Xie
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - Jyothisri Kondapalli
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - Jack Mordell
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - Richard B. Silverman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
- Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics, Northwestern University, Evanston, Illinois 60208, United States
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
| | - D. James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, United States
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10
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Cdk5 phosphorylates Ca V1.3 channels and regulates GABA A-mediated miniature inhibitory post-synaptic currents in striato-nigral terminals. Biochem Biophys Res Commun 2020; 524:255-261. [PMID: 31983427 DOI: 10.1016/j.bbrc.2020.01.084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/15/2020] [Indexed: 12/24/2022]
Abstract
Neurotransmission is one of the most important processes in neuronal communication and depends largely on Ca2+ entering synaptic terminals through voltage-gated Ca2+ (CaV) channels. Although the contribution of L-type CaV channels in neurotransmission has not been unambiguously established, increasing evidence suggests a role for these proteins in noradrenaline, dopamine, and GABA release. Here we report the regulation of L-type channels by Cdk5, and its possible effect on GABA release in the substantia nigra pars reticulata (SNpr). Using patch-clamp electrophysiology, we show that Cdk5 inhibition by Olomoucine significantly increases current density through CaV1.3 (L-type) channels heterologously expressed in HEK293 cells. Likewise, in vitro phosphorylation showed that Cdk5 phosphorylates residue S1947 in the C-terminal region of the pore-forming subunit of CaV1.3 channels. Consistent with this, the mutation of serine into alanine (S1947A) prevented the regulation of Cdk5 on CaV1.3 channel activity. Our data also revealed that the inhibition of Cdk5 increased the frequency of high K+-evoked miniature inhibitory postsynaptic currents in rat SNpr neurons, acting on L-type channels. These results unveil a novel regulatory mechanism of GABA release in the SNpr that involves a direct action of Cdk5 on L-type channels.
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11
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Verma A, Ravindranath V. Ca V1.3 L-Type Calcium Channels Increase the Vulnerability of Substantia Nigra Dopaminergic Neurons in MPTP Mouse Model of Parkinson's Disease. Front Aging Neurosci 2020; 11:382. [PMID: 32009942 PMCID: PMC6978652 DOI: 10.3389/fnagi.2019.00382] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/30/2019] [Indexed: 12/16/2022] Open
Abstract
Mechanisms underlying the selective vulnerability of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) over those in the ventral tegmental area (VTA) to degeneration in Parkinson’s disease (PD) remain poorly understood. DA neurons of SNpc and VTA are autonomous pacemakers but pacemaking in SNpc but not in VTA is accompanied by calcium influx through L-type calcium channel, CaV1.3 contributing to increased intracellular calcium and hence to cell death. CaV1.342A, an alternatively spliced short variant of CaV1.3 has increased calcium influx. We, therefore studied the role of CaV1.342 (full-length channel) and CaV1.342A in mouse SNpc in PD pathogenesis by quantifying mRNA levels of CaV1.342 and CaV1.342A in SNpc and followed the change in their levels in MPTP induced parkinsonism mouse model. Using in situ hybridization and immunohistochemistry we observed the localization of mRNA of CaV1.342 and CaV1.342A in tyrosine hydroxylase (TH) positive DA neurons. Further, mRNA levels of CaV1.342A were higher in SNpc as compared to the cortex. Upon MPTP treatment, mRNA levels of CaV1.342 and CaV1.342A maintained their levels in SNpc in spite of the loss of ~50% of the DA neurons. This indicates that the expression of CaV1.342 and CaV1.342A is maintained at a robust level during the degenerative process in the parkinsonism model.
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Affiliation(s)
- Aditi Verma
- Centre for Neuroscience, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Vijayalakshmi Ravindranath
- Centre for Neuroscience, Division of Biological Sciences, Indian Institute of Science, Bangalore, India.,Centre for Brain Research, Indian Institute of Science, Bangalore, India
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12
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Huang H, Kapeli K, Jin W, Wong YP, Arumugam TV, Koh JH, Srimasorn S, Mallilankaraman K, Chua JJE, Yeo GW, Soong TW. Tissue-selective restriction of RNA editing of CaV1.3 by splicing factor SRSF9. Nucleic Acids Res 2019; 46:7323-7338. [PMID: 29733375 PMCID: PMC6101491 DOI: 10.1093/nar/gky348] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/30/2018] [Indexed: 12/31/2022] Open
Abstract
Adenosine DeAminases acting on RNA (ADAR) catalyzes adenosine-to-inosine (A-to-I) conversion within RNA duplex structures. While A-to-I editing is often dynamically regulated in a spatial-temporal manner, the mechanisms underlying its tissue-selective restriction remain elusive. We have previously reported that transcripts of voltage-gated calcium channel CaV1.3 are subject to brain-selective A-to-I RNA editing by ADAR2. Here, we show that editing of CaV1.3 mRNA is dependent on a 40 bp RNA duplex formed between exon 41 and an evolutionarily conserved editing site complementary sequence (ECS) located within the preceding intron. Heterologous expression of a mouse minigene that contained the ECS, intermediate intronic sequence and exon 41 with ADAR2 yielded robust editing. Interestingly, editing of CaV1.3 was potently inhibited by serine/arginine-rich splicing factor 9 (SRSF9). Mechanistically, the inhibitory effect of SRSF9 required direct RNA interaction. Selective down-regulation of SRSF9 in neurons provides a basis for the neuron-specific editing of CaV1.3 transcripts.
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Affiliation(s)
- Hua Huang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore
| | - Katannya Kapeli
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Wenhao Jin
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Yuk Peng Wong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore
| | - Thiruma Valavan Arumugam
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Joanne Huifen Koh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Sumitra Srimasorn
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Karthik Mallilankaraman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - John Jia En Chua
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore.,Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Gene W Yeo
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California, San Diego, La Jolla, USA.,Molecular Engineering Laboratory, A*STAR, Singapore, Singapore
| | - Tuck Wah Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.,Neurobiology/Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore 117456, Singapore
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13
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A Selectivity Filter Gate Controls Voltage-Gated Calcium Channel Calcium-Dependent Inactivation. Neuron 2019; 101:1134-1149.e3. [DOI: 10.1016/j.neuron.2019.01.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/12/2018] [Accepted: 12/31/2018] [Indexed: 11/22/2022]
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14
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Liss B, Striessnig J. The Potential of L-Type Calcium Channels as a Drug Target for Neuroprotective Therapy in Parkinson's Disease. Annu Rev Pharmacol Toxicol 2019; 59:263-289. [PMID: 30625283 DOI: 10.1146/annurev-pharmtox-010818-021214] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The motor symptoms of Parkinson's disease (PD) mainly arise from degeneration of dopamine neurons within the substantia nigra. As no disease-modifying PD therapies are available, and side effects limit long-term benefits of current symptomatic therapies, novel treatment approaches are needed. The ongoing phase III clinical study STEADY-PD is investigating the potential of the dihydropyridine isradipine, an L-type Ca2+ channel (LTCC) blocker, for neuroprotective PD therapy. Here we review the clinical and preclinical rationale for this trial and discuss potential reasons for the ambiguous outcomes of in vivo animal model studies that address PD-protective dihydropyridine effects. We summarize current views about the roles of Cav1.2 and Cav1.3 LTCC isoforms for substantia nigra neuron function, and their high vulnerability to degenerative stressors, and for PD pathophysiology. We discuss different dihydropyridine sensitivities of LTCC isoforms in view of their potential as drug targets for PD neuroprotection, and we conclude by considering how these aspects could guide further drug development.
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Affiliation(s)
- Birgit Liss
- Institut für Angewandte Physiologie, Universität Ulm, 89081 Ulm, Germany;
| | - Jörg Striessnig
- Abteilung Pharmakologie und Toxikologie, Institut für Pharmazie, and Center for Molecular Biosciences Innsbruck, Universität Innsbruck, A-6020 Innsbruck, Austria;
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15
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Nussinovitch I. Ca2+ Channels in Anterior Pituitary Somatotrophs: A Therapeutic Perspective. Endocrinology 2018; 159:4043-4055. [PMID: 30395240 DOI: 10.1210/en.2018-00743] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 10/26/2018] [Indexed: 01/18/2023]
Abstract
Ca2+ influx through voltage-gated Ca2+ channels (VGCCs) plays a key role in GH secretion. In this review, we summarize the current state of knowledge regarding the physiology and molecular machinery of VGCCs in pituitary somatotrophs. We next discuss the possible involvement of Ca2+ channelopathies in pituitary disease and the potential use of Ca2+ channel blockers to treat pituitary disease. Various types of VGCCs exist in pituitary cells. However, because L-type Ca2+ channels (LTCCs) contribute the major component to Ca2+ influx in somatotrophs, lactotrophs, and corticotrophs, we focused on these channels. An increasing number of studies in recent years have linked genetic missense mutations in LTCCs to diseases of the human cardiovascular, nervous, and endocrine systems. These disease-associated genetic mutations occur at homologous functional positions (activation gates) in LTCCs. Thus, it is plausible that similar homologous missense mutations in pituitary LTCCs can cause abnormal hormone secretion and underlying pituitary disorders. The existence of LTCCs in pituitary cells opens questions about their sensitivity to dihydropyridines, a group of selective LTCC blockers. The dihydropyridine sensitivity of pituitary cells, as with any other excitable cell, depends primarily on two parameters: the pattern of their electrical activity and the dihydropyridine sensitivity of their LTCC isoforms. These two parameters are discussed in detail in relation to somatotrophs. These discussions are also relevant to lactotrophs and corticotrophs. High dihydropyridine sensitivity may facilitate their use as drugs to treat pituitary oversecretion disorders such as acromegaly, hyperprolactinemia, and Cushing disease.
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Affiliation(s)
- Itzhak Nussinovitch
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University Faculty of Medicine, Jerusalem, Israel
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16
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Wang Y, Tang S, Harvey KE, Salyer AE, Li TA, Rantz EK, Lill MA, Hockerman GH. Molecular Determinants of the Differential Modulation of Ca v1.2 and Ca v1.3 by Nifedipine and FPL 64176. Mol Pharmacol 2018; 94:973-983. [PMID: 29980657 PMCID: PMC11033928 DOI: 10.1124/mol.118.112441] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/28/2018] [Indexed: 11/22/2022] Open
Abstract
Nifedipine and FPL 64176 (FPL), which block and potentiate L-type voltage-gated Ca2+ channels, respectively, modulate Cav1.2 more potently than Cav1.3. To identify potential strategies for developing subtype-selective inhibitors, we investigated the role of divergent amino acid residues in transmembrane domains IIIS5 and the extracellular IIIS5-3P loop region in modulation of these channels by nifedipine and FPL. Insertion of the extracellular IIIS5-3P loop from Cav1.2 into Cav1.3 (Cav1.3+) reduced the IC50 of nifedipine from 289 to 101 nM, and substitution of S1100 with an A residue, as in Cav1.2, accounted for this difference. Substituting M1030 in IIIS5 to V in Cav1.3+ (Cav1.3+V) further reduced the IC50 of nifedipine to 42 nM. FPL increased current amplitude with an EC50 of 854 nM in Cav1.3, 103 nM in Cav1.2, and 99 nM in Cav1.3+V. In contrast to nifedipine block, substitution of M1030 to V in Cav1.3 had no effect on potency of FPL potentiation of current amplitude, but slowed deactivation in the presence and absence of 10 μM FPL. FPL had no effect on deactivation of Cav1.3/dihydropyridine-insensitive (DHPi), a channel with very low sensitivity to nifedipine block (IC50 ∼93 μM), but did shift the voltage-dependence of activation by ∼-10 mV. We conclude that the M/V variation in IIIS5 and the S/A variation in the IIIS5-3P loop of Cav1.2 and Cav1.3 largely determine the difference in nifedipine potency between these two channels, but the difference in FPL potency is determined by divergent amino acids in the IIIS5-3P loop.
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Affiliation(s)
- Yuchen Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Shiqi Tang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Kyle E Harvey
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Amy E Salyer
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - T August Li
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Emily K Rantz
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Markus A Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Gregory H Hockerman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
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17
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Niu J, Yang W, Yue DT, Inoue T, Ben-Johny M. Duplex signaling by CaM and Stac3 enhances Ca V1.1 function and provides insights into congenital myopathy. J Gen Physiol 2018; 150:1145-1161. [PMID: 29950399 PMCID: PMC6080896 DOI: 10.1085/jgp.201812005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/23/2018] [Accepted: 05/11/2018] [Indexed: 01/24/2023] Open
Abstract
CaV1.1 is essential for skeletal muscle excitation-contraction coupling. Its functional expression is tuned by numerous regulatory proteins, yet underlying modulatory mechanisms remain ambiguous as CaV1.1 fails to function in heterologous systems. In this study, by dissecting channel trafficking versus gating, we evaluated the requirements for functional CaV1.1 in heterologous systems. Although coexpression of the auxiliary β subunit is sufficient for surface-membrane localization, this baseline trafficking is weak, and channels elicit a diminished open probability. The regulatory proteins calmodulin and stac3 independently enhance channel trafficking and gating via their interaction with the CaV1.1 carboxy terminus. Myopathic stac3 mutations weaken channel binding and diminish trafficking. Our findings demonstrate that multiple regulatory proteins orchestrate CaV1.1 function via duplex mechanisms. Our work also furnishes insights into the pathophysiology of stac3-associated congenital myopathy and reveals novel avenues for pharmacological intervention.
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Affiliation(s)
- Jacqueline Niu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | - Wanjun Yang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | | | - Takanari Inoue
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD
- Center for Cell Dynamics, Institute for Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY
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18
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Ca 2+ protein alpha 1D of CaV1.3 regulates intracellular calcium concentration and migration of colon cancer cells through a non-canonical activity. Sci Rep 2017; 7:14199. [PMID: 29079724 PMCID: PMC5660277 DOI: 10.1038/s41598-017-14230-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/03/2017] [Indexed: 01/05/2023] Open
Abstract
It is generally accepted that voltage-gated Ca2+ channels, CaV, regulate Ca2+ homeostasis in excitable cells following plasma membrane depolarization. Here, we show that the Ca2+ protein α1D of CaV1.3 channel is overexpressed in colorectal cancer biopsies compared to normal tissues. Gene silencing experiments targeting α1D reduced the migration and the basal cytosolic Ca2+ concentration of HCT116 colon cancer cell line and modified the cytosolic Ca2+ oscillations induced by the sodium/calcium exchanger NCX1/3 working in its reverse mode. Interestingly, NCX1/3 regulated membrane potential of HCT116 cells only when α1D was silenced, and blocking NCX1/3 increased cytosolic Ca2+ concentration and cell migration. However, membrane depolarization did not induce an increase in intracellular Ca2+. Patch-clamp experiments clearly showed that the inward Ca2+ current was absent. Finally, flow cytometry and immunofluorescence studies showed that α1D protein was localized at the plasma membrane, in cytosol and cell nuclei. Altogether, we uncover a novel signaling pathway showing that α1D is involved in the regulation of Ca2+ homeostasis and cell migration by a mechanism independent of its plasma membrane canonical function but that involved plasma membrane Na+/Ca2+ exchanger.
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19
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Activity-Dependent Facilitation of Ca V1.3 Calcium Channels Promotes KCa3.1 Activation in Hippocampal Neurons. J Neurosci 2017; 37:11255-11270. [PMID: 29038242 DOI: 10.1523/jneurosci.0967-17.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 10/02/2017] [Accepted: 10/07/2017] [Indexed: 11/21/2022] Open
Abstract
CaV1 L-type calcium channels are key to regulating neuronal excitability, with the range of functional roles enhanced by interactions with calmodulin, accessory proteins, or CaMKII that modulate channel activity. In hippocampal pyramidal cells, a prominent elevation of CaV1 activity is apparent in late channel openings that can last for seconds following a depolarizing stimulus train. The current study tested the hypothesis that a reported interaction among CaV1.3 channels, the scaffolding protein densin, and CaMKII could generate a facilitation of channel activity that outlasts a depolarizing stimulus. We found that CaV1.3 but not CaV1.2 channels exhibit a long-duration calcium-dependent facilitation (L-CDF) that lasts up to 8 s following a brief 50 Hz stimulus train, but only when coexpressed with densin and CaMKII. To test the physiological role for CaV1.3 L-CDF, we coexpressed the intermediate-conductance KCa3.1 potassium channel, revealing a strong functional coupling to CaV1.3 channel activity that was accentuated by densin and CaMKII. Moreover, the CaV1.3-densin-CaMKII interaction gave rise to an outward tail current of up to 8 s duration following a depolarizing stimulus in both tsA-201 cells and male rat CA1 pyramidal cells. A slow afterhyperpolarization in pyramidal cells was reduced by a selective block of CaV1 channels by isradipine, a CaMKII blocker, and siRNA knockdown of densin, and spike frequency increased upon selective block of CaV1 channel conductance. The results are important in revealing a CaV1.3-densin-CaMKII interaction that extends the contribution of CaV1.3 calcium influx to a time frame well beyond a brief input train.SIGNIFICANCE STATEMENT CaV1 L-type calcium channels play a key role in regulating the output of central neurons by providing calcium influx during repetitive inputs. This study identifies a long-duration calcium-dependent facilitation (L-CDF) of CaV1.3 channels that depends on the scaffolding protein densin and CaMKII and that outlasts a depolarizing stimulus by seconds. We further show a tight functional coupling between CaV1.3 calcium influx and the intermediate-conductance KCa3.1 potassium channel that promotes an outward tail current of up to 8 s following a depolarizing stimulus. Tests in CA1 hippocampal pyramidal cells reveal that a slow AHP is reduced by blocking different components of the CaV1.3-densin-CaMKII interaction, identifying an important role for CaV1.3 L-CDF in regulating neuronal excitability.
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20
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Ca V1.3 L-type Ca 2+ channel contributes to the heartbeat by generating a dihydropyridine-sensitive persistent Na + current. Sci Rep 2017; 7:7869. [PMID: 28801600 PMCID: PMC5554211 DOI: 10.1038/s41598-017-08191-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/07/2017] [Indexed: 11/22/2022] Open
Abstract
The spontaneous activity of sinoatrial node (SAN) pacemaker cells is generated by a functional interplay between the activity of ionic currents of the plasma membrane and intracellular Ca2+ dynamics. The molecular correlate of a dihydropyridine (DHP)-sensitive sustained inward Na+ current (Ist), a key player in SAN automaticity, is still unknown. Here we show that Ist and the L-type Ca2+ current (ICa,L) share CaV1.3 as a common molecular determinant. Patch-clamp recordings of mouse SAN cells showed that Ist is activated in the diastolic depolarization range, and displays Na+ permeability and minimal inactivation and sensitivity to ICa,L activators and blockers. Both CaV1.3-mediated ICa,L and Ist were abolished in CaV1.3-deficient (CaV1.3−/−) SAN cells but the CaV1.2-mediated ICa,L current component was preserved. In SAN cells isolated from mice expressing DHP-insensitive CaV1.2 channels (CaV1.2DHP−/−), Ist and CaV1.3-mediated ICa,L displayed overlapping sensitivity and concentration–response relationships to the DHP blocker nifedipine. Consistent with the hypothesis that CaV1.3 rather than CaV1.2 underlies Ist, a considerable fraction of ICa,L was resistant to nifedipine inhibition in CaV1.2DHP−/− SAN cells. These findings identify CaV1.3 channels as essential molecular components of the voltage-dependent, DHP-sensitive Ist Na+ current in the SAN.
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21
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Pinggera A, Mackenroth L, Rump A, Schallner J, Beleggia F, Wollnik B, Striessnig J. New gain-of-function mutation shows CACNA1D as recurrently mutated gene in autism spectrum disorders and epilepsy. Hum Mol Genet 2017; 26:2923-2932. [PMID: 28472301 PMCID: PMC5886262 DOI: 10.1093/hmg/ddx175] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 05/01/2017] [Accepted: 05/02/2017] [Indexed: 11/12/2022] Open
Abstract
CACNA1D encodes the pore-forming α1-subunit of Cav1.3, an L-type voltage-gated Ca2+-channel. Despite the recent discovery of two de novo missense gain-of-function mutations in Cav1.3 in two individuals with autism spectrum disorder (ASD) and intellectual disability CACNA1D has not been considered a prominent ASD-risk gene in large scale genetic analyses, since such studies primarily focus on likely-disruptive genetic variants. Here we report the discovery and characterization of a third de novo missense mutation in CACNA1D (V401L) in a patient with ASD and epilepsy. For the functional characterization we introduced mutation V401L into two major C-terminal long and short Cav1.3 splice variants, expressed wild-type or mutant channel complexes in tsA-201 cells and performed whole-cell patch-clamp recordings. Mutation V401L, localized within the channel's activation gate, significantly enhanced current densities, shifted voltage dependence of activation and inactivation to more negative voltages and reduced channel inactivation in both Cav1.3 splice variants. Altogether, these gating changes are expected to result in enhanced Ca2+-influx through the channel, thus representing a strong gain-of-function phenotype. Additionally, we also found that mutant channels retained full sensitivity towards the clinically available Ca2+ -channel blocker isradipine. Our findings strengthen the evidence for CACNA1D as a novel candidate autism risk gene and encourage experimental therapy with available channel-blockers for this mutation. The additional presence of seizures and neurological abnormalities in our patient define a novel phenotype partially overlapping with symptoms in two individuals with PASNA (congenital primary aldosteronism, seizures and neurological abnormalities) caused by similar Cav1.3 gain-of-function mutations.
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Affiliation(s)
- Alexandra Pinggera
- Department of Pharmacology and Toxicology Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | | | | | - Jens Schallner
- Abteilung Neuropädiatrie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Filippo Beleggia
- Department I of Internal Medicine, University Hospital of Cologne, 50923 Cologne, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
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22
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Ortner NJ, Bock G, Dougalis A, Kharitonova M, Duda J, Hess S, Tuluc P, Pomberger T, Stefanova N, Pitterl F, Ciossek T, Oberacher H, Draheim HJ, Kloppenburg P, Liss B, Striessnig J. Lower Affinity of Isradipine for L-Type Ca 2+ Channels during Substantia Nigra Dopamine Neuron-Like Activity: Implications for Neuroprotection in Parkinson's Disease. J Neurosci 2017; 37:6761-6777. [PMID: 28592699 PMCID: PMC6596555 DOI: 10.1523/jneurosci.2946-16.2017] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 05/08/2017] [Accepted: 05/13/2017] [Indexed: 12/21/2022] Open
Abstract
Ca2+-influx through L-type Ca2+-channels (LTCCs) is associated with activity-related stressful oscillations of Ca2+ levels within dopaminergic (DA) neurons in the substantia nigra (SN), which may contribute to their selective degeneration in Parkinson's disease (PD). LTCC blockers were neuroprotective in mouse neurotoxin models of PD, and isradipine is currently undergoing testing in a phase III clinical trial in early PD. We report no evidence for neuroprotection by in vivo pretreatment with therapeutically relevant isradipine plasma levels, or Cav1.3 LTCC deficiency in 6-OHDA-treated male mice. To explain this finding, we investigated the pharmacological properties of human LTCCs during SN DA-like and arterial smooth muscle (aSM)-like activity patterns using whole-cell patch-clamp recordings in HEK293 cells (Cav1.2 α1-subunit, long and short Cav1.3 α1-subunit splice variants; β3/α2δ1). During SN DA-like pacemaking, only Cav1.3 variants conducted Ca2+ current (ICa) at subthreshold potentials between action potentials. SN DA-like burst activity increased integrated ICa during (Cav1.2 plus Cav1.3) and after (Cav1.3) the burst. Isradipine inhibition was splice variant and isoform dependent, with a 5- to 11-fold lower sensitivity to Cav1.3 variants during SN DA-like pacemaking compared with Cav1.2 during aSM-like activity. Supratherapeutic isradipine concentrations reduced the pacemaker precision of adult mouse SN DA neurons but did not affect their somatic Ca2+ oscillations. Our data predict that Cav1.2 and Cav1.3 splice variants contribute differentially to Ca2+ load in SN DA neurons, with prominent Cav1.3-mediated ICa between action potentials and after bursts. The failure of therapeutically relevant isradipine levels to protect SN DA neurons can be explained by weaker state-dependent inhibition of SN DA LTCCs compared with aSM Cav1.2.SIGNIFICANCE STATEMENT The high vulnerability of dopamine (DA) neurons in the substantia nigra (SN) to neurodegenerative stressors causes Parkinson's disease (PD). Ca2+ influx through voltage-gated L-type Ca2+ channels (LTCCs), in particular Cav1.3, appears to contribute to this vulnerability, and the LTCC inhibitor isradipine is currently being tested as a neuroprotective agent for PD in a phase III clinical trial. However, in our study isradipine plasma concentrations approved for therapy were not neuroprotective in a PD mouse model. We provide an explanation for this observation by demonstrating that during SN DA-like neuronal activity LTCCs are less sensitive to isradipine than Cav1.2 LTCCs in resistance blood vessels (mediating dose-limiting vasodilating effects) and even at supratherapeutic concentrations isradipine fails to reduce somatic Ca2+ oscillations of SN DA neurons.
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Affiliation(s)
- Nadine J Ortner
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Gabriella Bock
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Antonios Dougalis
- Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Maria Kharitonova
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Johanna Duda
- Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Simon Hess
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Pomberger
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Florian Pitterl
- Institute of Legal Medicine and Core Facility Metabolomics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Ciossek
- Boehringer Ingelheim Pharma GmbH & Co KG, CNS Research, 88400 Biberach an der Riss, Germany, and
| | - Herbert Oberacher
- Institute of Legal Medicine and Core Facility Metabolomics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Henning J Draheim
- Boehringer Ingelheim Pharma GmbH & Co KG, CNS Research, 88400 Biberach an der Riss, Germany, and
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria,
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23
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Different Ca V1.3 Channel Isoforms Control Distinct Components of the Synaptic Vesicle Cycle in Auditory Inner Hair Cells. J Neurosci 2017; 37:2960-2975. [PMID: 28193694 DOI: 10.1523/jneurosci.2374-16.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 01/27/2017] [Accepted: 02/01/2017] [Indexed: 12/16/2022] Open
Abstract
The mechanisms orchestrating transient and sustained exocytosis in auditory inner hair cells (IHCs) remain largely unknown. These exocytotic responses are believed to mobilize sequentially a readily releasable pool of vesicles (RRP) underneath the synaptic ribbons and a slowly releasable pool of vesicles (SRP) at farther distance from them. They are both governed by Cav1.3 channels and require otoferlin as Ca2+ sensor, but whether they use the same Cav1.3 isoforms is still unknown. Using whole-cell patch-clamp recordings in posthearing mice, we show that only a proportion (∼25%) of the total Ca2+ current in IHCs displaying fast inactivation and resistance to 20 μm nifedipine, a l-type Ca2+ channel blocker, is sufficient to trigger RRP but not SRP exocytosis. This Ca2+ current is likely conducted by short C-terminal isoforms of Cav1.3 channels, notably Cav1.342A and Cav1.343S, because their mRNA is highly expressed in wild-type IHCs but poorly expressed in Otof-/- IHCs, the latter having Ca2+ currents with considerably reduced inactivation. Nifedipine-resistant RRP exocytosis was poorly affected by 5 mm intracellular EGTA, suggesting that the Cav1.3 short isoforms are closely associated with the release site at the synaptic ribbons. Conversely, our results suggest that Cav1.3 long isoforms, which carry ∼75% of the total IHC Ca2+ current with slow inactivation and confer high sensitivity to nifedipine and to internal EGTA, are essentially involved in recruiting SRP vesicles. Intracellular Ca2+ imaging showed that Cav1.3 long isoforms support a deep intracellular diffusion of Ca2+SIGNIFICANCE STATEMENT Auditory inner hair cells (IHCs) encode sounds into nerve impulses through fast and indefatigable Ca2+-dependent exocytosis at their ribbon synapses. We show that this synaptic process involves long and short C-terminal isoforms of the Cav1.3 Ca2+ channel that differ in the kinetics of their Ca2+-dependent inactivation and their relative sensitivity to the l-type Ca2+ channel blocker nifedipine. The short C-terminal isoforms, having fast inactivation and low sensitivity to nifedipine, mainly control the fast fusion of the readily releasable pool (RRP); that is, they encode the phasic exocytotic component. The long isoforms, with slow inactivation and great sensitivity to nifedipine, mainly regulate the vesicular replenishment of the RRP; that is, the sustained or tonic exocytosis.
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24
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Stanika R, Campiglio M, Pinggera A, Lee A, Striessnig J, Flucher BE, Obermair GJ. Splice variants of the Ca V1.3 L-type calcium channel regulate dendritic spine morphology. Sci Rep 2016; 6:34528. [PMID: 27708393 PMCID: PMC5052568 DOI: 10.1038/srep34528] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/15/2016] [Indexed: 01/13/2023] Open
Abstract
Dendritic spines are the postsynaptic compartments of glutamatergic synapses in the brain. Their number and shape are subject to change in synaptic plasticity and neurological disorders including autism spectrum disorders and Parkinson’s disease. The L-type calcium channel CaV1.3 constitutes an important calcium entry pathway implicated in the regulation of spine morphology. Here we investigated the importance of full-length CaV1.3L and two C-terminally truncated splice variants (CaV1.342A and CaV1.343S) and their modulation by densin-180 and shank1b for the morphology of dendritic spines of cultured hippocampal neurons. Live-cell immunofluorescence and super-resolution microscopy of epitope-tagged CaV1.3L revealed its localization at the base-, neck-, and head-region of dendritic spines. Expression of the short splice variants or deletion of the C-terminal PDZ-binding motif in CaV1.3L induced aberrant dendritic spine elongation. Similar morphological alterations were induced by co-expression of densin-180 or shank1b with CaV1.3L and correlated with increased CaV1.3 currents and dendritic calcium signals in transfected neurons. Together, our findings suggest a key role of CaV1.3 in regulating dendritic spine structure. Under physiological conditions it may contribute to the structural plasticity of glutamatergic synapses. Conversely, altered regulation of CaV1.3 channels may provide an important mechanism in the development of postsynaptic aberrations associated with neurodegenerative disorders.
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Affiliation(s)
- Ruslan Stanika
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Marta Campiglio
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Alexandra Pinggera
- Department of Pharmacology and Toxicology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, and Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Bernhard E Flucher
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Gerald J Obermair
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
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25
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Lipscombe D, Andrade A. Calcium Channel CaVα₁ Splice Isoforms - Tissue Specificity and Drug Action. Curr Mol Pharmacol 2016; 8:22-31. [PMID: 25966698 DOI: 10.2174/1874467208666150507103215] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 01/20/2015] [Accepted: 04/20/2015] [Indexed: 12/11/2022]
Abstract
Voltage-gated calcium ion channels are essential for numerous biological functions of excitable cells and there is wide spread appreciation of their importance as drug targets in the treatment of many disorders including those of cardiovascular and nervous systems. Each Cacna1 gene has the potential to generate a number of structurally, functionally, and in some cases pharmacologically unique CaVα1 subunits through alternative pre-mRNA splicing and the use of alternate promoters. Analyses of rapidly emerging deep sequencing data for a range of human tissue transcriptomes contain information to quantify tissue-specific and alternative exon usage patterns for Cacna1 genes. Cellspecific actions of nuclear DNA and RNA binding proteins control the use of alternate promoters and the selection of alternate exons during pre-mRNA splicing, and they determine the spectrum of protein isoforms expressed within different types of cells. Amino acid compositions within discrete protein domains can differ substantially among CaV isoforms expressed in different tissues, and such differences may be greater than those that exist across CaV channel homologs of closely related species. Here we highlight examples of CaV isoforms that have unique expression patterns and that exhibit different pharmacological sensitivities. Knowledge of expression patterns of CaV isoforms in different human tissues, cell populations, ages, and disease states should inform strategies aimed at developing the next generation of CaV channel inhibitors and agonists with improved tissue-specificity.
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Affiliation(s)
- Diane Lipscombe
- Department of Neuroscience, Brown University. Providence, RI, USA.
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26
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Striessnig J, Ortner NJ, Pinggera A. Pharmacology of L-type Calcium Channels: Novel Drugs for Old Targets? Curr Mol Pharmacol 2016; 8:110-22. [PMID: 25966690 PMCID: PMC5384371 DOI: 10.2174/1874467208666150507105845] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/10/2015] [Accepted: 04/20/2015] [Indexed: 11/22/2022]
Abstract
Inhibition of voltage-gated L-type calcium channels by organic calcium channel blockers is a well-established pharmacodynamic concept for the treatment of hypertension and cardiac ischemia. Since decades these antihypertensives (such as the dihydropyridines amlodipine, felodipine or nifedipine) belong to the most widely prescribed drugs
world-wide. Their tolerability is excellent because at therapeutic doses their pharmacological effects in humans are limited to the cardiovascular system. During the last years substantial progress has been made to reveal the physiological role of different L-type calcium channel isoforms in many other tissues, including the brain, endocrine and sensory cells.
Moreover, there is accumulating evidence about their involvement in various human diseases, such as Parkinson's disease, neuropsychiatric disorders and hyperaldosteronism. In this review we discuss the pathogenetic role of L-type calcium channels, potential new indications for existing or isoform-selective compounds and strategies to minimize potential side effects.
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Affiliation(s)
- Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, A-6020 Innsbruck, Austria.
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27
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Buchanan PJ, McCloskey KD. Ca V channels and cancer: canonical functions indicate benefits of repurposed drugs as cancer therapeutics. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:621-633. [PMID: 27342111 PMCID: PMC5045480 DOI: 10.1007/s00249-016-1144-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 05/17/2016] [Accepted: 05/23/2016] [Indexed: 01/19/2023]
Abstract
The importance of ion channels in the hallmarks of many cancers is increasingly recognised. This article reviews current knowledge of the expression of members of the voltage-gated calcium channel family (CaV) in cancer at the gene and protein level and discusses their potential functional roles. The ten members of the CaV channel family are classified according to expression of their pore-forming α-subunit; moreover, co-expression of accessory α2δ, β and γ confers a spectrum of biophysical characteristics including voltage dependence of activation and inactivation, current amplitude and activation/inactivation kinetics. CaV channels have traditionally been studied in excitable cells including neurones, smooth muscle, skeletal muscle and cardiac cells, and drugs targeting the channels are used in the treatment of hypertension and epilepsy. There is emerging evidence that several CaV channels are differentially expressed in cancer cells compared to their normal counterparts. Interestingly, a number of CaV channels also have non-canonical functions and are involved in transcriptional regulation of the expression of other proteins including potassium channels. Pharmacological studies show that CaV canonical function contributes to the fundamental biology of proliferation, cell-cycle progression and apoptosis. This raises the intriguing possibility that calcium channel blockers, approved for the treatment of other conditions, could be repurposed to treat particular cancers. Further research will reveal the full extent of both the canonical and non-canonical functions of CaV channels in cancer and whether calcium channel blockers are beneficial in cancer treatment.
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Affiliation(s)
- Paul J Buchanan
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, Northern Ireland, BT9 7AE, UK.,National Institute of Cellular Biotechnology, School of Nursing and Human Science, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Karen D McCloskey
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, Northern Ireland, BT9 7AE, UK.
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28
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Limpitikul WB, Dick IE, Ben-Johny M, Yue DT. An autism-associated mutation in CaV1.3 channels has opposing effects on voltage- and Ca(2+)-dependent regulation. Sci Rep 2016; 6:27235. [PMID: 27255217 PMCID: PMC4891671 DOI: 10.1038/srep27235] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/13/2016] [Indexed: 01/07/2023] Open
Abstract
CaV1.3 channels are a major class of L-type Ca(2+) channels which contribute to the rhythmicity of the heart and brain. In the brain, these channels are vital for excitation-transcription coupling, synaptic plasticity, and neuronal firing. Moreover, disruption of CaV1.3 function has been associated with several neurological disorders. Here, we focus on the de novo missense mutation A760G which has been linked to autism spectrum disorder (ASD). To explore the role of this mutation in ASD pathogenesis, we examined the effects of A760G on CaV1.3 channel gating and regulation. Introduction of the mutation severely diminished the Ca(2+)-dependent inactivation (CDI) of CaV1.3 channels, an important feedback system required for Ca(2+) homeostasis. This reduction in CDI was observed in two major channel splice variants, though to different extents. Using an allosteric model of channel gating, we found that the underlying mechanism of CDI reduction is likely due to enhanced channel opening within the Ca(2+)-inactivated mode. Remarkably, the A760G mutation also caused an opposite increase in voltage-dependent inactivation (VDI), resulting in a multifaceted mechanism underlying ASD. When combined, these regulatory deficits appear to increase the intracellular Ca(2+) concentration, thus potentially disrupting neuronal development and synapse formation, ultimately leading to ASD.
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Affiliation(s)
- Worawan B Limpitikul
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713,720 Rutland Avenue, Baltimore, MD 21205, USA
| | - Ivy E Dick
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713,720 Rutland Avenue, Baltimore, MD 21205, USA
| | - Manu Ben-Johny
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713,720 Rutland Avenue, Baltimore, MD 21205, USA
| | - David T Yue
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713,720 Rutland Avenue, Baltimore, MD 21205, USA
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29
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Frolov RV, Weckström M. Harnessing the Flow of Excitation: TRP, Voltage-Gated Na(+), and Voltage-Gated Ca(2+) Channels in Contemporary Medicine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:25-95. [PMID: 26920687 DOI: 10.1016/bs.apcsb.2015.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular signaling in both excitable and nonexcitable cells involves several classes of ion channels. Some of them are of minor importance, with very specialized roles in physiology, but here we concentrate on three major channel classes: TRP (transient receptor potential channels), voltage-gated sodium channels (Nav), and voltage-gated calcium channels (Cav). Here, we first propose a conceptual framework binding together all three classes of ion channels, a "flow-of-excitation model" that takes into account the inputs mediated by TRP and other similar channels, the outputs invariably provided by Cav channels, and the regenerative transmission of signals in the neural networks, for which Nav channels are responsible. We use this framework to examine the function, structure, and pharmacology of these channel classes both at cellular and also at whole-body physiological level. Building on that basis we go through the pathologies arising from the direct or indirect malfunction of the channels, utilizing ion channel defects, the channelopathies. The pharmacological interventions affecting these channels are numerous. Part of those are well-established treatments, like treatment of hypertension or some forms of epilepsy, but many other are deeply problematic due to poor drug specificity, ion channel diversity, and widespread expression of the channels in tissues other than those actually targeted.
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Affiliation(s)
- Roman V Frolov
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland.
| | - Matti Weckström
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland
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30
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Zamponi GW, Striessnig J, Koschak A, Dolphin AC. The Physiology, Pathology, and Pharmacology of Voltage-Gated Calcium Channels and Their Future Therapeutic Potential. Pharmacol Rev 2015; 67:821-70. [PMID: 26362469 PMCID: PMC4630564 DOI: 10.1124/pr.114.009654] [Citation(s) in RCA: 719] [Impact Index Per Article: 79.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type Ca(V)1.2 calcium channels, particularly 1,4-dihydropyridines, which are widely used in the treatment of hypertension. T-type (Ca(V)3) channels are a target of ethosuximide, widely used in absence epilepsy. The auxiliary subunit α2δ-1 is the therapeutic target of the gabapentinoid drugs, which are of value in certain epilepsies and chronic neuropathic pain. The limited use of intrathecal ziconotide, a peptide blocker of N-type (Ca(V)2.2) calcium channels, as a treatment of intractable pain, gives an indication that these channels represent excellent drug targets for various pain conditions. We describe how selectivity for different subtypes of calcium channels (e.g., Ca(V)1.2 and Ca(V)1.3 L-type channels) may be achieved in the future by exploiting differences between channel isoforms in terms of sequence and biophysical properties, variation in splicing in different target tissues, and differences in the properties of the target tissues themselves in terms of membrane potential or firing frequency. Thus, use-dependent blockers of the different isoforms could selectively block calcium channels in particular pathologies, such as nociceptive neurons in pain states or in epileptic brain circuits. Of important future potential are selective Ca(V)1.3 blockers for neuropsychiatric diseases, neuroprotection in Parkinson's disease, and resistant hypertension. In addition, selective or nonselective T-type channel blockers are considered potential therapeutic targets in epilepsy, pain, obesity, sleep, and anxiety. Use-dependent N-type calcium channel blockers are likely to be of therapeutic use in chronic pain conditions. Thus, more selective calcium channel blockers hold promise for therapeutic intervention.
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Affiliation(s)
- Gerald W Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
| | - Joerg Striessnig
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
| | - Alexandra Koschak
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
| | - Annette C Dolphin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada (G.W.Z.); Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria (J.S., A.K.); and Department of Neuroscience, Physiology, and Pharmacology, Division of Biosciences, University College London, London, United Kingdom (A.C.D.)
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31
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Reichhart N, Markowski M, Ishiyama S, Wagner A, Crespo-Garcia S, Schorb T, Ramalho JS, Milenkovic VM, Föckler R, Seabra MC, Strauß O. Rab27a GTPase modulates L-type Ca2+ channel function via interaction with the II-III linker of CaV1.3 subunit. Cell Signal 2015; 27:2231-40. [PMID: 26235199 DOI: 10.1016/j.cellsig.2015.07.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/28/2015] [Indexed: 12/31/2022]
Abstract
In a variety of cells, secretory processes require the activation of both Rab27a and L-type channels of the Ca(V)1.3 subtype. In the retinal pigment epithelium (RPE), Rab27a and Ca(V)1.3 channels regulate growth-factor secretion towards its basolateral side. Analysis of murine retina sections revealed a co-localization of both Rab27a and Ca(V)1.3 at the basolateral membrane of the RPE. Heterologously expressed Ca(V)1.3/β3/α2δ1 channels showed negatively shifted voltage-dependence and decreased current density of about 70% when co-expressed with Rab27a. However, co-localization analysis using α(5)β(1) integrin as a membrane marker revealed that Rab27a co-expression reduced the surface expression of Ca(V)1.3 only about 10%. Physical binding of heterologously expressed Rab27a with Ca(V)1.3 channels was shown by co-localization in immunocytochemistry as well as co-immunoprecipitation which was abolished after deletion of a MyRIP-homologous amino acid sequence at the II-III linker of the Ca(V)1.3 subunit. Rab27a over-expression in ARPE-19 cells positively shifted the voltage dependence, decreased current density of endogenous Ca(V)1.3 channels and reduced VEGF-A secretion. We show the first evidence of a direct functional modulation of an ion channel by Rab27a suggesting a new mechanism of Rab and ion channel interaction in the control of VEGF-A secretion in the RPE.
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Affiliation(s)
- Nadine Reichhart
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Magdalena Markowski
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Shimpei Ishiyama
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Andrea Wagner
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Sergio Crespo-Garcia
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - Talitha Schorb
- Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany
| | - José S Ramalho
- CEDOC, Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, Lisbon, Portugal
| | - Vladimir M Milenkovic
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Department of Psychiatry and Psychotherapy, Molecular Neuroscience, University of Regensburg, Germany
| | - Renate Föckler
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany
| | - Miguel C Seabra
- CEDOC, Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, Lisbon, Portugal
| | - Olaf Strauß
- Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Regensburg, Germany; Experimental Ophthalmology, Eye Hospital, Charité University Medicine, Campus Virchow-Clinic, Berlin, Germany.
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32
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Soong TW, Mori MX. Post-transcriptional modifications and "Calmodulation" of voltage-gated calcium channel function: Reflections by two collaborators of David T Yue. Channels (Austin) 2015; 10:14-9. [PMID: 26054929 DOI: 10.1080/19336950.2015.1051271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
This review article is written to specially pay tribute to David T. Yue who was an outstanding human being and an excellent scientist who exuded passion and creativity. He exemplified an inter-disciplinary scientist who was able to cross scientific boundaries effortlessly in order to provide amazing understanding on how calcium channels work. This article provides a glimpse of some of the research the authors have the privilege to collaborate with David and it attempts to provide the thinking behind some of the research done. In a wider context, we highlight that calcium channel function could be exquisitely modulated by interaction with a tethered calmodulin. Post-transcriptional modifications such as alternative splicing and RNA editing further influence the Ca(2+)-CaM mediated processes such as calcium dependent inhibition and/or facilitation. Besides modifications of electrophysiological and pharmacological properties, protein interactions with the channels could also be influenced in a splice-variant dependent manner.
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Affiliation(s)
- Tuck Wah Soong
- a Department of Physiology ; Yong Loo Lin School of Medicine; National University of Singapore ; Singapore.,b NUS Graduate School for Integrative Science and Engineering, and Neurobiology/Aging Program ; Singapore.,c National Neuroscience Institute ; Singapore
| | - Masayuki X Mori
- d Kyoto University Department of Synthetic Chemistry and Biological Chemistry ; Graduate School of Engineering, Kyoto University ; Kyoto , Japan
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33
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Liao P, Yu D, Hu Z, Liang MC, Wang JJ, Yu CY, Ng G, Yong TF, Soon JL, Chua YL, Soong TW. Alternative splicing generates a novel truncated Cav1.2 channel in neonatal rat heart. J Biol Chem 2015; 290:9262-72. [PMID: 25694430 DOI: 10.1074/jbc.m114.594911] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 11/06/2022] Open
Abstract
L-type Cav1.2 Ca(2+) channel undergoes extensive alternative splicing, generating functionally different channels. Alternatively spliced Cav1.2 Ca(2+) channels have been found to be expressed in a tissue-specific manner or under pathological conditions. To provide a more comprehensive understanding of alternative splicing in Cav1.2 channel, we systematically investigated the splicing patterns in the neonatal and adult rat hearts. The neonatal heart expresses a novel 104-bp exon 33L at the IVS3-4 linker that is generated by the use of an alternative acceptor site. Inclusion of exon 33L causes frameshift and C-terminal truncation. Whole-cell electrophysiological recordings of Cav1.233L channels expressed in HEK 293 cells did not detect any current. However, when co-expressed with wild type Cav1.2 channels, Cav1.233L channels reduced the current density and altered the electrophysiological properties of the wild type Cav1.2 channels. Interestingly, the truncated 3.5-domain Cav1.233L channels also yielded a dominant negative effect on Cav1.3 channels, but not on Cav3.2 channels, suggesting that Cavβ subunits is required for Cav1.233L regulation. A biochemical study provided evidence that Cav1.233L channels enhanced protein degradation of wild type channels via the ubiquitin-proteasome system. Although the physiological significance of the Cav1.233L channels in neonatal heart is still unknown, our report demonstrates the ability of this novel truncated channel to modulate the activity of the functional Cav1.2 channels. Moreover, the human Cav1.2 channel also contains exon 33L that is developmentally regulated in heart. Unexpectedly, human exon 33L has a one-nucleotide insertion that allowed in-frame translation of a full Cav1.2 channel. An electrophysiological study showed that human Cav1.233L channel is a functional channel but conducts Ca(2+) ions at a much lower level.
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Affiliation(s)
- Ping Liao
- From the National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Duke-NUS Graduate Medical School Singapore, Singapore 169857,
| | - Dejie Yu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, and
| | - Zhenyu Hu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, and
| | - Mui Cheng Liang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, and
| | - Jue Jin Wang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, and
| | - Chye Yun Yu
- From the National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433
| | - Gandi Ng
- From the National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433
| | - Tan Fong Yong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, and
| | - Jia Lin Soon
- National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609
| | - Yeow Leng Chua
- National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609
| | - Tuck Wah Soong
- From the National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, and
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34
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Hurley MJ, Gentleman SM, Dexter DT. Calcium CaV1 channel subtype mRNA expression in Parkinson's disease examined by in situ hybridization. J Mol Neurosci 2014; 55:715-24. [PMID: 25173401 DOI: 10.1007/s12031-014-0410-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/20/2014] [Indexed: 12/12/2022]
Abstract
The factors which make some neurons vulnerable to neurodegeneration in Parkinson's disease while others remain resistant are not fully understood. Studies in animal models of Parkinson's disease suggest that preferential use of CaV1.3 subtypes by neurons may contribute to the neurodegenerative process by increasing mitochondrial oxidant stress. This study quantified the level of mRNA for the CaV1 subtypes found in the brain by in situ hybridization using CaV1 subtype-specific [(35)S]-radiolabelled oligonucleotide probes. In normal brain, the greatest amount of messenger RNA (mRNA) for each CaV1 subtype was found in the midbrain (substantia nigra), with a moderate level in the pons (locus coeruleus) and lower quantities in cerebral cortex (cingulate and primary motor). In Parkinson's disease, the level of CaV1 subtype mRNA was maintained in the midbrain and pons, despite cell loss in these areas. In cingulate cortex, CaV1.2 and CaV1.3 mRNA increased in cases with late-stage Parkinson's disease. In primary motor cortex, the level of CaV1.2 mRNA increased in late-stage Parkinson's disease. The level of CaV1.3 mRNA increased in primary motor cortex of cases with early-stage Parkinson's disease and normalized to near the control level in cases from late-stage Parkinson's disease. The finding of elevated CaV1 subtype expression in cortical brain regions supports the view that disturbed calcium homeostasis is a feature of Parkinson's disease throughout brain and not only a compensatory consequence to the neurodegenerative process in areas of cell loss.
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Affiliation(s)
- Michael J Hurley
- Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK,
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35
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Telinius N, Mohanakumar S, Majgaard J, Kim S, Pilegaard H, Pahle E, Nielsen J, de Leval M, Aalkjaer C, Hjortdal V, Boedtkjer DB. Human lymphatic vessel contractile activity is inhibited in vitro but not in vivo by the calcium channel blocker nifedipine. J Physiol 2014; 592:4697-714. [PMID: 25172950 DOI: 10.1113/jphysiol.2014.276683] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Calcium channel blockers (CCB) are widely prescribed anti-hypertensive agents. The commonest side-effect, peripheral oedema, is attributed to a larger arterial than venous dilatation causing increased fluid filtration. Whether CCB treatment is detrimental to human lymphatic vessel function and thereby exacerbates oedema formation is unknown. We observed that spontaneous lymphatic contractions in isolated human vessels (thoracic duct and mesenteric lymphatics) maintained under isometric conditions were inhibited by therapeutic concentrations (nanomolar) of the CCB nifedipine while higher than therapeutic concentrations of verapamil (micromolar) were necessary to inhibit activity. Nifedipine also inhibited spontaneous action potentials measured by sharp microelectrodes. Furthermore, noradrenaline did not elicit normal increases in lymphatic vessel tone when maximal constriction was reduced to 29.4 ± 4.9% of control in the presence of 20 nmol l(-1) nifedipine. Transcripts for the L-type calcium channel gene CACNA1C were consistently detected from human thoracic duct samples examined and the CaV1.2 protein was localized by immunoreactivity to lymphatic smooth muscle cells. While human lymphatics ex vivo were highly sensitive to nifedipine, this was not apparent in vivo when nifedipine was compared to placebo in a randomized, double-blinded clinical trial: conversely, lymphatic vessel contraction frequency was increased and refill time was faster despite all subjects achieving target nifedipine plasma concentrations. We conclude that human lymphatic vessels are highly sensitive to nifedipine in vitro but that care must be taken when extrapolating in vitro observations of lymphatic vessel function to the clinical situation, as similar changes in lymphatic function were not evident in our clinical trial comparing nifedipine treatment to placebo.
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Affiliation(s)
- Niklas Telinius
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Department of Cardiothoracic Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - Sheyanth Mohanakumar
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Department of Cardiothoracic Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - Jens Majgaard
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Sukhan Kim
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Hans Pilegaard
- Department of Cardiothoracic Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - Einar Pahle
- Department of Surgery, Viborg Hospital, Viborg, Denmark
| | - Jørn Nielsen
- Department of Surgery, Viborg Hospital, Viborg, Denmark
| | - Marc de Leval
- International Congenital Cardiac Centre, Harley Street Clinic, London, UK
| | | | - Vibeke Hjortdal
- Department of Cardiothoracic Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - Donna Briggs Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Department of Cardiothoracic Surgery, Aarhus University Hospital, Aarhus, Denmark
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36
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Huang H, Ng CY, Yu D, Zhai J, Lam Y, Soong TW. Modest CaV1.342-selective inhibition by compound 8 is β-subunit dependent. Nat Commun 2014; 5:4481. [PMID: 25057870 PMCID: PMC4124865 DOI: 10.1038/ncomms5481] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/20/2014] [Indexed: 01/20/2023] Open
Abstract
Two voltage-gated calcium channel subtypes—CaV1.2 and CaV1.3—underlie the major L-type Ca2+ currents in the mammalian central nervous system. Owing to their high sequence homology, the two channel subtypes share similar pharmacological properties, and at high doses classic calcium channel blockers, such as dihydropyridines, phenylalkylamines and benzothiazepines, do not discriminate between the two channel subtypes. Recent progress in treating Parkinson’s disease (PD) was marked by the discovery of synthetic compound 8, which was reported to be a highly selective inhibitor of the CaV1.3 L-type calcium channels (LTCC). However, despite a previously reported IC50 of ~24 μM, in our hands inhibition of the full-length CaV1.342 by compound 8 at 50 μM reaches a maximum of 45%. Moreover, we find that the selectivity of compound 8 towards CaV1.3 relative to CaV1.2B15 channels is greatly influenced by the β-subunit type and its splice isoform variants. Compound 8-1-(3-chlorophenethyl)-3-cyclopentylpyrimidine-2,4,6(1H,3H,5H)-trione was previously reported to be a selective inhibitor of the CaV1.3 calcium channel. Now, Huang et al. demonstrate that selectivity towards CaV1.3 relative to CaV1.2 is dependent on the type of β-subunit and CaV1.3 splice variant assayed.
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Affiliation(s)
- Hua Huang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Cheng Yang Ng
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Dejie Yu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Jing Zhai
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Yulin Lam
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Tuck Wah Soong
- 1] Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore [2] NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456, Singapore [3] Neurobiology/Ageing Programme, National University of Singapore, Singapore 117456, Singapore [4] National Neuroscience Institute, Jalan Tan Tock Seng, Singapore 308433, Singapore
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