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Lindner JS, Rajayer SR, Martiszus BJ, Smith SM. Cinacalcet inhibition of neuronal action potentials preferentially targets the fast inactivated state of voltage-gated sodium channels. Front Physiol 2022; 13:1066467. [PMID: 36601343 PMCID: PMC9806421 DOI: 10.3389/fphys.2022.1066467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Voltage-gated sodium channel (VGSC) activation is essential for action potential generation in the brain. Allosteric calcium-sensing receptor (CaSR) agonist, cinacalcet, strongly and ubiquitously inhibits VGSC currents in neocortical neurons via an unidentified, G-protein-dependent inhibitory molecule. Here, using whole-cell patch VGSC clamp methods, we investigated the voltage-dependence of cinacalcet-mediated inhibition of VGSCs and the channel state preference of cinacalcet. The rate of inhibition of VGSC currents was accelerated at more depolarized holding potentials. Cinacalcet shifted the voltage-dependence of both fast and slow inactivation of VGSC currents in the hyperpolarizing direction. Utilizing a simple model, the voltage-dependence of VGSC current inhibition may be explained if the affinity of the inhibitory molecule to the channel states follows the sequence: fast-inactivated > slow-inactivated > resting. The state dependence of VGSC current inhibition contributes to the non-linearity of action potential block by cinacalcet. This dynamic and abundant signaling pathway by which cinacalcet regulates VGSC currents provides an important voltage-dependent mechanism for modulating central neuronal excitability.
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Affiliation(s)
- Jamie S Lindner
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Salil R Rajayer
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Briana J Martiszus
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Stephen M Smith
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
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Lopez-Charcas O, Pukkanasut P, Velu SE, Brackenbury WJ, Hales TG, Besson P, Gomora JC, Roger S. Pharmacological and nutritional targeting of voltage-gated sodium channels in the treatment of cancers. iScience 2021; 24:102270. [PMID: 33817575 PMCID: PMC8010468 DOI: 10.1016/j.isci.2021.102270] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Voltage-gated sodium (NaV) channels, initially characterized in excitable cells, have been shown to be aberrantly expressed in non-excitable cancer tissues and cells from epithelial origins such as in breast, lung, prostate, colon, and cervix, whereas they are not expressed in cognate non-cancer tissues. Their activity was demonstrated to promote aggressive and invasive potencies of cancer cells, both in vitro and in vivo, whereas their deregulated expression in cancer tissues has been associated with metastatic progression and cancer-related death. This review proposes NaV channels as pharmacological targets for anticancer treatments providing opportunities for repurposing existing NaV-inhibitors or developing new pharmacological and nutritional interventions.
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Affiliation(s)
- Osbaldo Lopez-Charcas
- Université de Tours, EA4245 Transplantation, Immunologie, Inflammation, Faculté de Médecine de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Piyasuda Pukkanasut
- Department of Chemistry, The University of Alabama at Birmingham, CHEM 280. 901, 14th Street S, Birmingham, AL 35294, USA
| | - Sadanandan E. Velu
- Department of Chemistry, The University of Alabama at Birmingham, CHEM 280. 901, 14th Street S, Birmingham, AL 35294, USA
| | - William J. Brackenbury
- Department of Biology, York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Tim G. Hales
- Institute of Academic Anaesthesia, Division of Systems Medicine, School of Medicine, the University of Dundee, DD1 9SY, Dundee, UK
| | - Pierre Besson
- Université de Tours, EA4245 Transplantation, Immunologie, Inflammation, Faculté de Médecine de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Juan Carlos Gomora
- Instituto de Fisiología Celular, Circuito Exterior s/n Ciudad Universitaria, Universidad Nacional Autónoma de México, Mexico City, 04510 México
| | - Sébastien Roger
- Université de Tours, EA4245 Transplantation, Immunologie, Inflammation, Faculté de Médecine de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
- Institut Universitaire de France, 75005 Paris, France
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Encinas AC, Watkins JC, Longoria IA, Johnson JP, Hammer MF. Variable patterns of mutation density among NaV1.1, NaV1.2 and NaV1.6 point to channel-specific functional differences associated with childhood epilepsy. PLoS One 2020; 15:e0238121. [PMID: 32845893 PMCID: PMC7449494 DOI: 10.1371/journal.pone.0238121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 08/10/2020] [Indexed: 11/28/2022] Open
Abstract
Variants implicated in childhood epilepsy have been identified in all four voltage-gated sodium channels that initiate action potentials in the central nervous system. Previous research has focused on the functional effects of particular variants within the most studied of these channels (NaV1.1, NaV1.2 and NaV1.6); however, there have been few comparative studies across channels to infer the impact of mutations in patients with epilepsy. Here we compare patterns of variation in patient and public databases to test the hypothesis that regions of known functional significance within voltage-gated sodium (NaV) channels have an increased burden of deleterious variants. We assessed mutational burden in different regions of the Nav channels by (1) performing Fisher exact tests on odds ratios to infer excess variants in domains, segments, and loops of each channel in patient databases versus public “control” databases, and (2) comparing the cumulative distribution of variant sites along DNA sequences of each gene in patient and public databases (i.e., independent of protein structure). Patient variant density was concordant among channels in regions known to play a role in channel function, with statistically significant higher patient variant density in S4-S6 and DIII-DIV and an excess of public variants in SI-S3, DI-DII, DII-DIII. On the other hand, channel-specific patterns of patient burden were found in the NaV1.6 inactivation gate and NaV1.1 S5-S6 linkers, while NaV1.2 and NaV1.6 S4-S5 linkers and S5 segments shared patient variant patterns that contrasted with those in NaV1.1. These different patterns may reflect different roles played by the NaV1.6 inactivation gate in action potential propagation, and by NaV1.1 S5-S6 linkers in loss of function and haploinsufficiency. Interestingly, NaV1.2 and NaV1.6 both lack amino acid substitutions over significantly long stretches in both the patient and public databases suggesting that new mutations in these regions may cause embryonic lethality or a non-epileptic disease phenotype.
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Affiliation(s)
- Alejandra C. Encinas
- Graduate Program in Genetics, University of Arizona, Tucson, Arizona, United States of America
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | - Iris Arenas Longoria
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | | | - Michael F. Hammer
- Department of Neurology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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Beard JM, Shockett PE, O'Reilly JP. Substituted cysteine scanning in D1-S6 of the sodium channel hNav1.4 alters kinetics and structural interactions of slow inactivation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183129. [PMID: 31738900 DOI: 10.1016/j.bbamem.2019.183129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 10/25/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
Slow inactivation in voltage-gated Na+ channels (Navs) plays an important physiological role in excitable tissues (muscle, heart, nerves) and mutations that disrupt Nav slow inactivation can result in pathophysiologies (myotonia, arrhythmias, epilepsy). While the molecular mechanisms responsible for slow inactivation remain elusive, previous studies have suggested a role for the pore-lining D1-S6 helix. The goals of this research were to determine if (1) cysteine substitutions in D1-S6 affect gating kinetics and (2) methanethiosulfonate ethylammonium (MTSEA) accessibility changes in different kinetic states. Site-directed mutagenesis in the human skeletal muscle isoform hNav1.4 was used to substitute cysteine for eleven amino acids in D1-S6 from L433 to L443. Mutants were expressed in HEK cells and recorded from with whole-cell patch clamp. All mutations affected one or more baseline kinetics of the sodium channel, including activation, fast inactivation, and slow inactivation. Substitution of cysteine (for nonpolar residues) adjacent to polar residues destabilized slow inactivation in G434C, F436C, I439C, and L441C. Cysteine substitution without adjacent polar residues enhanced slow inactivation in L438C and N440C, and disrupted possible H-bonds involving Y437:D4 S4-S5 and N440:D4-S6. MTSEA exposure in closed, fast-inactivated, or slow-inactivated states in most mutants had little-to-no effect. In I439C, MTSEA application in closed, fast-inactivated, and slow-inactivated states produced irreversible reduction in current, suggesting I439C accessibility to MTSEA in all three kinetic states. D1-S6 is important for Nav gating kinetics, stability of slow-inactivated state, structural contacts, and state-dependent positioning. However, prominent reconfiguration of D1-S6 may not occur in slow inactivation.
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Affiliation(s)
- Jonathan M Beard
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA, USA.
| | - Penny E Shockett
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA, USA.
| | - John P O'Reilly
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA, USA.
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