1
|
Rangel-Galván M, Rangel-Galván V, Rangel-Huerta A. T-type calcium channel modulation by hydrogen sulfide in neuropathic pain conditions. Front Pharmacol 2023; 14:1212800. [PMID: 37529702 PMCID: PMC10387653 DOI: 10.3389/fphar.2023.1212800] [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: 04/26/2023] [Accepted: 07/05/2023] [Indexed: 08/03/2023] Open
Abstract
Neuropathic pain can appear as a direct or indirect nerve damage lesion or disease that affects the somatosensory nervous system. If the neurons are damaged or indirectly stimulated, immune cells contribute significantly to inflammatory and neuropathic pain. After nerve injury, peripheral macrophages/spinal microglia accumulate around damaged neurons, producing endogenous hydrogen sulfide (H2S) through the cystathionine-γ-lyase (CSE) enzyme. H2S has a pronociceptive modulation on the Cav3.2 subtype, the predominant Cav3 isoform involved in pain processes. The present review provides relevant information about H2S modulation on the Cav3.2 T-type channels in neuropathic pain conditions. We have discussed that the dual effect of H2S on T-type channels is concentration-dependent, that is, an inhibitory effect is seen at low concentrations of 10 µM and an augmentation effect on T-current at 100 µM. The modulation mechanism of the Cav3.2 channel by H2S involves the direct participation of the redox/Zn2+ affinity site located in the His191 in the extracellular loop of domain I of the channel, involving a group of extracellular cysteines, comprising C114, C123, C128, and C1333, that can modify the local redox environment. The indirect interaction pathways involve the regulation of the Cav3.2 channel through cytokines, kinases, and post-translational regulators of channel expression. The findings conclude that the CSE/H2S/Cav3.2 pathway could be a promising therapeutic target for neuropathic pain disorders.
Collapse
Affiliation(s)
- Maricruz Rangel-Galván
- Biothecnology Department, Metropolitan Polytechnic University of Puebla, Puebla, Puebla, Mexico
| | - Violeta Rangel-Galván
- Nursing and Physiotherapy Department, University of Professional Development, Tijuana, Baja California, Mexico
| | - Alejandro Rangel-Huerta
- Faculty of Computer Science, Meritorious Autonomous University of Puebla, Puebla, Puebla, Mexico
| |
Collapse
|
2
|
Fuchs E, Messerer DAC, Karpel-Massler G, Fauler M, Zimmer T, Jungwirth B, Föhr KJ. Block of Voltage-Gated Sodium Channels as a Potential Novel Anti-cancer Mechanism of TIC10. Front Pharmacol 2021; 12:737637. [PMID: 34744721 PMCID: PMC8567104 DOI: 10.3389/fphar.2021.737637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/15/2021] [Indexed: 12/19/2022] Open
Abstract
Background: Tumor therapeutics are aimed to affect tumor cells selectively while sparing healthy ones. For this purpose, a huge variety of different drugs are in use. Recently, also blockers of voltage-gated sodium channels (VGSCs) have been recognized to possess potentially beneficial effects in tumor therapy. As these channels are a frequent target of numerous drugs, we hypothesized that currently used tumor therapeutics might have the potential to block VGSCs in addition to their classical anti-cancer activity. In the present work, we have analyzed the imipridone TIC10, which belongs to a novel class of anti-cancer compounds, for its potency to interact with VGSCs. Methods: Electrophysiological experiments were performed by means of the patch-clamp technique using heterologously expressed human heart muscle sodium channels (hNav1.5), which are among the most common subtypes of VGSCs occurring in tumor cells. Results: TIC10 angular inhibited the hNav1.5 channel in a state- but not use-dependent manner. The affinity for the resting state was weak with an extrapolated Kr of about 600 μM. TIC10 most probably did not interact with fast inactivation. In protocols for slow inactivation, a half-maximal inhibition occurred around 2 µM. This observation was confirmed by kinetic studies indicating that the interaction occurred with a slow time constant. Furthermore, TIC10 also interacted with the open channel with an affinity of approximately 4 µM. The binding site for local anesthetics or a closely related site is suggested as a possible target as the affinity for the well-characterized F1760K mutant was reduced more than 20-fold compared to wild type. Among the analyzed derivatives, ONC212 was similarly effective as TIC10 angular, while TIC10 linear more selectively interacted with the different states. Conclusion: The inhibition of VGSCs at low micromolar concentrations might add to the anti-tumor properties of TIC10.
Collapse
Affiliation(s)
- Eva Fuchs
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| | | | | | - Michael Fauler
- Institute of General Physiology, University of Ulm, Ulm, Germany
| | - Thomas Zimmer
- Institute of Physiology, University Hospital of Jena, Jena, Germany
| | - Bettina Jungwirth
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| | - Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| |
Collapse
|
3
|
Carlson EJ, Georg GI, Hawkinson JE. Steroidal Antagonists of Progesterone- and Prostaglandin E 1-Induced Activation of the Cation Channel of Sperm. Mol Pharmacol 2021; 101:56-67. [PMID: 34718225 PMCID: PMC8969127 DOI: 10.1124/molpharm.121.000349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/23/2021] [Indexed: 12/18/2022] Open
Abstract
The cation channel of sperm (CatSper) is the principal entry point for calcium in human spermatozoa and its proper function is essential for successful fertilization. As CatSper is potently activated by progesterone, we evaluated a range of steroids to define the structure-activity relationships for channel activation and found that CatSper is activated by a broad range of steroids with diverse structural modifications. By testing steroids that failed to elicit calcium influx as inhibitors of channel activation, we discovered that medroxyprogesterone acetate, levonorgestrel, and aldosterone inhibited calcium influx produced by progesterone, prostaglandin E1, and the fungal natural product l-sirenin, but these steroidal inhibitors failed to prevent calcium influx in response to elevated K+ and pH. In contrast to these steroid antagonists, we demonstrated for the first time that the T-type calcium channel blocker ML218 acts similarly to mibefradil, blocking CatSper channels activated by both ligands and alkalinization/depolarization. These T-type calcium channel blockers produced an insurmountable blockade of CatSper, whereas the three steroids produced antagonism that was surmountable by increasing concentrations of each activator, indicating that the steroids selectively antagonize ligand-induced activation of CatSper rather than blocking channel function. Both the channel blockers and the steroid antagonists markedly reduced hyperactivated motility of human sperm assessed by computer-aided sperm analysis, consistent with inhibition of CatSper activation. Unlike the channel blockers mibefradil and ML218, which reduced total and progressive motility, medroxyprogesterone acetate, levonorgestrel, and aldosterone had little effect on these motility parameters, indicating that these steroids are selective inhibitors of hyperactivated sperm motility. SIGNIFICANCE STATEMENT: The steroids medroxyprogesterone acetate, levonorgestrel, and aldosterone selectively antagonize progesterone- and prostaglandin E1-induced calcium influx through the CatSper cation channel in human sperm. In contrast to T-type calcium channel blockers that prevent all modes of CatSper activation, these steroid CatSper antagonists preferentially reduce hyperactivated sperm motility, which is required for fertilization. The discovery of competitive antagonists of ligand-induced CatSper activation provides starting points for future discovery of male contraceptive agents acting by this unique mechanism.
Collapse
Affiliation(s)
- Erick J Carlson
- Department of Medicinal Chemistry (E.J.C., G.I.G., J.E.H.) and Institute for Therapeutics Discovery and Development (G.I.G., J.E.H.), University of Minnesota, Minneapolis, Minnesota
| | - Gunda I Georg
- Department of Medicinal Chemistry (E.J.C., G.I.G., J.E.H.) and Institute for Therapeutics Discovery and Development (G.I.G., J.E.H.), University of Minnesota, Minneapolis, Minnesota
| | - Jon E Hawkinson
- Department of Medicinal Chemistry (E.J.C., G.I.G., J.E.H.) and Institute for Therapeutics Discovery and Development (G.I.G., J.E.H.), University of Minnesota, Minneapolis, Minnesota
| |
Collapse
|
4
|
Du Y, Tikhonov DB, Nomura Y, Dong K, Zhorov BS. Mutational analysis of state-dependent contacts in the pore module of eukaryotic sodium channels. Arch Biochem Biophys 2018; 652:59-70. [PMID: 29936083 DOI: 10.1016/j.abb.2018.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/06/2018] [Accepted: 06/20/2018] [Indexed: 02/04/2023]
Abstract
Voltage-gated sodium channels have residues that change or may change contacts upon gating. Contributions of individual contacts in stability of different states are incompletely understood. Pore-lining inner helices contain exceptionally conserved asparagines in positions i20. Here we explored how mutations in positions i20 and i29 affect electrophysiological properties of insect sodium channels. In repeat interfaces I/IV, III/II and IV/III, alanine substitutions caused positive activation shifts in positions i20 and i29, negative shifts of slow inactivation in positions i20 and positive shifts of slow inactivation in positions i29. The results support the hypothesis on open state inter-repeat H-bonding of residues i20 and i29. The shift magnitudes vary between interfaces, reflecting structural asymmetry of the channels. Mutations in positions i20 of repeats III and IV caused much longer recovery delay from the slow and fast inactivation than other mutations. In repeat IV, alanine substitution of tyrosine i30 rescued positive activation shift of mutation in position i29. Our data suggest that polar residues in positions i29 are involved in stabilization of both the open and slow-inactivated states. Transition between the states may involve switching of H-bonding partners of residues i29 from the conserved asparagines to currently unknown residues.
Collapse
Affiliation(s)
- Yuzhe Du
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
| | - Denis B Tikhonov
- Sechenov Institute of Evolutionary Physiology & Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Yoshiko Nomura
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
| | - Ke Dong
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI 48824, USA
| | - Boris S Zhorov
- Sechenov Institute of Evolutionary Physiology & Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
| |
Collapse
|
5
|
Mutagenesis of the NaChBac sodium channel discloses a functional role for a conserved S6 asparagine. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:665-674. [PMID: 28825121 PMCID: PMC5599482 DOI: 10.1007/s00249-017-1246-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/21/2017] [Accepted: 07/29/2017] [Indexed: 12/11/2022]
Abstract
Asparagine is conserved in the S6 transmembrane segments of all voltage-gated sodium, calcium, and TRP channels identified to date. A broad spectrum of channelopathies including cardiac arrhythmias, epilepsy, muscle diseases, and pain disorders is associated with its mutation. To investigate its effects on sodium channel functional properties, we mutated the simple prokaryotic sodium channel NaChBac. Electrophysiological characterization of the N225D mutant reveals that this conservative substitution shifts the voltage-dependence of inactivation by 25 mV to more hyperpolarized potentials. The mutant also displays greater thermostability, as determined by synchrotron radiation circular dichroism spectroscopy studies of purified channels. Based on our analyses of high-resolution structures of NaChBac homologues, we suggest that the side-chain amine group of asparagine 225 forms one or more hydrogen bonds with different channel elements and that these interactions are important for normal channel function. The N225D mutation eliminates these hydrogen bonds and the structural consequences involve an enhanced channel inactivation.
Collapse
|
6
|
Nozaki Y, Honda Y, Watanabe H, Saiki S, Koyabu K, Itoh T, Nagasawa C, Nakamori C, Nakayama C, Iwasaki H, Suzuki S, Tanaka K, Takahashi E, Miyamoto K, Morimura K, Yamanishi A, Endo H, Shinozaki J, Nogawa H, Shinozawa T, Saito F, Kunimatsu T. CSAHi study-2: Validation of multi-electrode array systems (MEA60/2100) for prediction of drug-induced proarrhythmia using human iPS cell-derived cardiomyocytes: Assessment of reference compounds and comparison with non-clinical studies and clinical information. Regul Toxicol Pharmacol 2017. [PMID: 28634147 DOI: 10.1016/j.yrtph.2017.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
With the aim of reconsidering ICH S7B and E14 guidelines, a new in vitro assay system has been subjected to worldwide validation to establish a better prediction platform for potential drug-induced QT prolongation and the consequent TdP in clinical practice. In Japan, CSAHi HEART team has been working on hiPS-CMs in the MEA (hiPS-CMs/MEA) under a standardized protocol and found no inter-facility or lot-to-lot variability for proarrhythmic risk assessment of 7 reference compounds. In this study, we evaluated the responses of hiPS-CMs/MEA to another 31 reference compounds associated with cardiac toxicities, and gene expression to further clarify the electrophysiological characteristics over the course of culture period. The hiPS-CMs/MEA assay accurately predicted reference compounds potential for arrhythmogenesis, and yielded results that showed better correlation with target concentrations of QTc prolongation or TdP in clinical setting than other current in vitro and in vivo assays. Gene expression analyses revealed consistent profiles in all samples within and among the testing facilities. This report would provide CiPA with informative guidance on the use of the hiPS-CMs/MEA assay, and promote the establishment of a new paradigm, beyond conventional in vitro and in vivo assays for cardiac safety assessment of new drugs.
Collapse
Affiliation(s)
- Yumiko Nozaki
- Preclinical Research Laboratories, Sumitomo Dainippon Pharma Co., Ltd., 3-1-98 Kasugade-naka, Konohana-ku, Osaka 554-0022, Japan.
| | - Yayoi Honda
- Preclinical Research Laboratories, Sumitomo Dainippon Pharma Co., Ltd., 3-1-98 Kasugade-naka, Konohana-ku, Osaka 554-0022, Japan
| | - Hitoshi Watanabe
- Preclinical Research Laboratories, Sumitomo Dainippon Pharma Co., Ltd., 3-1-98 Kasugade-naka, Konohana-ku, Osaka 554-0022, Japan
| | - Shota Saiki
- Research Laboratory for Development, Shionogi & Co., Ltd., 3-1-1, Futaba-cho, Toyonaka, Osaka 561-0825, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan
| | - Kiyotaka Koyabu
- Research Laboratory for Development, Shionogi & Co., Ltd., 3-1-1, Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Tetsuji Itoh
- Research Laboratory for Development, Shionogi & Co., Ltd., 3-1-1, Futaba-cho, Toyonaka, Osaka 561-0825, Japan
| | - Chiho Nagasawa
- Drug Safety, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Kita-ku, Saitama-shi, Saitama 331-9530, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan
| | - Chiaki Nakamori
- Drug Safety, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Kita-ku, Saitama-shi, Saitama 331-9530, Japan
| | - Chiaki Nakayama
- Drug Safety, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Kita-ku, Saitama-shi, Saitama 331-9530, Japan
| | - Hiroshi Iwasaki
- Drug Safety, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Kita-ku, Saitama-shi, Saitama 331-9530, Japan
| | - Shinobu Suzuki
- Nippon Boehringer Ingelheim Co., Ltd., 6-7-5, Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Kohji Tanaka
- Nippon Boehringer Ingelheim Co., Ltd., 6-7-5, Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Etsushi Takahashi
- Research Laboratories, Toyama Chemical Co., Ltd., 4-1, Shimookui 2-chome, Toyama 930-8508, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan
| | - Kaori Miyamoto
- Research Laboratories, Toyama Chemical Co., Ltd., 4-1, Shimookui 2-chome, Toyama 930-8508, Japan
| | - Kaoru Morimura
- Research Laboratories, Toyama Chemical Co., Ltd., 4-1, Shimookui 2-chome, Toyama 930-8508, Japan
| | - Atsuhiro Yamanishi
- Toxicology Research Laboratory, Kyorin Pharmaceutical Co., Ltd., 1848, Nogi, Nogi-machi, Shimotsuga-gun, Tochigi 329-0114, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan
| | - Hiroko Endo
- Toxicology Research Laboratory, Kyorin Pharmaceutical Co., Ltd., 1848, Nogi, Nogi-machi, Shimotsuga-gun, Tochigi 329-0114, Japan
| | - Junko Shinozaki
- Toxicology Research Laboratory, Kyorin Pharmaceutical Co., Ltd., 1848, Nogi, Nogi-machi, Shimotsuga-gun, Tochigi 329-0114, Japan
| | - Hisashi Nogawa
- Toxicology Research Laboratory, Kyorin Pharmaceutical Co., Ltd., 1848, Nogi, Nogi-machi, Shimotsuga-gun, Tochigi 329-0114, Japan
| | - Tadahiro Shinozawa
- Drug Safety Research Laboratories, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome Fujisawa, Kanagawa 251-8555, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan; Japan Pharmaceutical Manufacturers Association, Drug Evaluation Committee, Non-Clinical Evaluation Expert Committee, Japan
| | - Fumiyo Saito
- Chemicals Assessment and Research Center, Chemicals Evaluation and Research Institute, Japan (CERI), 1600, Shimotakano, Sugito-machi, Kitakatsushika-gun, Saitama 345-0043, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan
| | - Takeshi Kunimatsu
- Preclinical Research Laboratories, Sumitomo Dainippon Pharma Co., Ltd., 3-1-98 Kasugade-naka, Konohana-ku, Osaka 554-0022, Japan; Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan; Japan Pharmaceutical Manufacturers Association, Drug Evaluation Committee, Non-Clinical Evaluation Expert Committee, Japan.
| |
Collapse
|
7
|
Schulze V, Stoetzer C, O'Reilly AO, Eberhardt E, Foadi N, Ahrens J, Wegner F, Lampert A, de la Roche J, Leffler A. The opioid methadone induces a local anaesthetic-like inhibition of the cardiac Na⁺ channel, Na(v)1.5. Br J Pharmacol 2014; 171:427-37. [PMID: 24117196 DOI: 10.1111/bph.12465] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 09/23/2013] [Accepted: 09/27/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Treatment with methadone is associated with severe cardiac arrhythmias, a side effect that seems to result from an inhibition of cardiac hERG K⁺ channels. However, several other opioids are inhibitors of voltage-gated Na⁺ channels. Considering the common assumption that an inhibition of the cardiac Na⁺ channel Na(v)1.5, is the primary mechanism for local anaesthetic (LA)-induced cardiotoxicity, we hypothesized that methadone has LA-like properties leading to a modulation of Na(v)1.5 channels. EXPERIMENTAL APPROACH The whole-cell patch clamp technique was applied to investigate the effects of methadone on wild-type and mutant human Na(v)1.5 channels expressed in HEK293 cells. A homology model of human Na(v)1.5 channels was used to perform automated ligand-docking studies. KEY RESULTS Methadone inhibited Na(v)1.5 channels in a state-dependent manner, that is, tonic block was stronger with inactivated channels than with resting channels and a use-dependent block at 10 Hz. Methadone induced a concentration-dependent shift of the voltage dependency of both fast and slow inactivation towards more hyperpolarized potentials, and impaired recovery from fast and slow inactivation. The LA-insensitive mutants N406K and F1760A exhibited reduced tonic and use-dependent block by methadone, and docking predictions positioned methadone in a cavity that was delimited by the residue F1760. Dextromethadone and levomethadone induced discrete stereo-selective effects on Na(v)1.5 channels. CONCLUSIONS AND IMPLICATIONS Methadone interacted with the LA-binding site to inhibit Na(v)1.5 channels. Our data suggest that these channels are a hitherto unrecognized molecular component contributing to cardiac arrhythmias induced by methadone.
Collapse
Affiliation(s)
- V Schulze
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Tikhonov DB, Bruhova I, Garden DP, Zhorov BS. State-dependent inter-repeat contacts of exceptionally conserved asparagines in the inner helices of sodium and calcium channels. Pflugers Arch 2014; 467:253-66. [DOI: 10.1007/s00424-014-1508-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 01/09/2023]
|
9
|
Wang GK, Wang SY. Block of human cardiac sodium channels by lacosamide: evidence for slow drug binding along the activation pathway. Mol Pharmacol 2014; 85:692-702. [PMID: 24563546 DOI: 10.1124/mol.113.091173] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lacosamide is an anticonvulsant hypothesized to enhance slow inactivation of neuronal Na(+) channels for its therapeutic action. Cardiac Na(+) channels display less and incomplete slow inactivation, but their sensitivity toward lacosamide remains unknown. We therefore investigated the action of lacosamide in human cardiac Nav1.5 and Nav1.5-CW inactivation-deficient Na(+) channels. Lacosamide showed little effect on hNav1.5 Na(+) currents at 300 µM when cells were held at -140 mV. With 30-second conditioning pulses from -90 to -50 mV; however, hNav1.5 Na(+) channels became sensitive to lacosamide with IC50 (50% inhibitory concentration) around 70-80 µM. Higher IC50 values were found at -110 and -30 mV. The development of lacosamide block at -70 mV was slow in wild-type Na(+) channels (τ; 8.04 ± 0.39 seconds, n = 8). This time constant was significantly accelerated in hNav1.5-CW inactivation-deficient counterparts. The recovery from lacosamide block at -70 mV for 10 seconds was relatively rapid in wild-type Na(+) channels (τ; 639 ± 90 milliseconds, n = 8). This recovery was accelerated further in hNav1.5-CW counterparts. Unexpectedly, lacosamide elicited a time-dependent block of persistent hNav1.5-CW Na(+) currents with an IC50 of 242 ± 19 µM (n = 5). Furthermore, both hNav1.5-CW/F1760K mutant and batrachotoxin-activated hNav1.5 Na(+) channels became completely lacosamide resistant, indicating that the lacosamide receptor overlaps receptors for local anesthetics and batrachotoxin. Our results together suggest that lacosamide targets the intermediate preopen and open states of hNav1.5 Na(+) channels. Lacosamide may thus track closely the conformational changes at the hNav1.5-F1760 region along the activation pathway.
Collapse
Affiliation(s)
- Ging Kuo Wang
- Department of Anesthesiology, Perioperative, Pain Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts (G.K.W.); and Department of Biological Sciences, SUNY at Albany, Albany, New York (S.-Y.W.)
| | | |
Collapse
|
10
|
Silva JR, Goldstein SAN. Voltage-sensor movements describe slow inactivation of voltage-gated sodium channels II: a periodic paralysis mutation in Na(V)1.4 (L689I). ACTA ACUST UNITED AC 2013; 141:323-34. [PMID: 23401572 PMCID: PMC3581693 DOI: 10.1085/jgp.201210910] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In skeletal muscle, slow inactivation (SI) of NaV1.4 voltage-gated sodium channels prevents spontaneous depolarization and fatigue. Inherited mutations in NaV1.4 that impair SI disrupt activity-induced regulation of channel availability and predispose patients to hyperkalemic periodic paralysis. In our companion paper in this issue (Silva and Goldstein. 2013. J. Gen. Physiol. http://dx.doi.org/10.1085/jgp.201210909), the four voltage sensors in NaV1.4 responsible for activation of channels over microseconds are shown to slowly immobilize over 1–160 s as SI develops and to regain mobility on recovery from SI. Individual sensor movements assessed via attached fluorescent probes are nonidentical in their voltage dependence, time course, and magnitude: DI and DII track SI onset, and DIII appears to reflect SI recovery. A causal link was inferred by tetrodotoxin (TTX) suppression of both SI onset and immobilization of DI and DII sensors. Here, the association of slow sensor immobilization and SI is verified by study of NaV1.4 channels with a hyperkalemic periodic paralysis mutation; L689I produces complex changes in SI, and these are found to manifest directly in altered sensor movements. L689I removes a component of SI with an intermediate time constant (∼10 s); the mutation also impedes immobilization of the DI and DII sensors over the same time domain in support of direct mechanistic linkage. A model that recapitulates SI attributes responsibility for intermediate SI to DI and DII (10 s) and a slow component to DIII (100 s), which accounts for residual SI, not impeded by L689I or TTX.
Collapse
Affiliation(s)
- Jonathan R Silva
- Department of Biochemistry, Brandeis University, Waltham, MA 02453, USA
| | | |
Collapse
|
11
|
Silva JR, Goldstein SAN. Voltage-sensor movements describe slow inactivation of voltage-gated sodium channels I: wild-type skeletal muscle Na(V)1.4. ACTA ACUST UNITED AC 2013; 141:309-21. [PMID: 23401571 PMCID: PMC3581692 DOI: 10.1085/jgp.201210909] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The number of voltage-gated sodium (NaV) channels available to generate action potentials in muscles and nerves is adjusted over seconds to minutes by prior electrical activity, a process called slow inactivation (SI). The basis for SI is uncertain. NaV channels have four domains (DI–DIV), each with a voltage sensor that moves in response to depolarizing stimulation over milliseconds to activate the channels. Here, SI of the skeletal muscle channel NaV1.4 is induced by repetitive stimulation and is studied by recording of sodium currents, gating currents, and changes in the fluorescence of probes on each voltage sensor to assess their movements. The magnitude, voltage dependence, and time course of the onset and recovery of SI are observed to correlate with voltage-sensor movements 10,000-fold slower than those associated with activation. The behavior of each voltage sensor is unique. Development of SI over 1–160 s correlates best with slow immobilization of the sensors in DI and DII; DIII tracks the onset of SI with less fidelity. Showing linkage to the sodium conduction pathway, pore block by tetrodotoxin affects both SI and immobilization of all the sensors, with DI and DII significantly suppressed. Recovery from SI correlates best with slow restoration of mobility of the sensor in DIII. The findings suggest that voltage-sensor movements determine SI and thereby mediate NaV channel availability.
Collapse
Affiliation(s)
- Jonathan R Silva
- Department of Biochemistry, Brandeis University, Waltham, MA 02453, USA
| | | |
Collapse
|
12
|
O’Reilly AO, Eberhardt E, Weidner C, Alzheimer C, Wallace BA, Lampert A. Bisphenol A binds to the local anesthetic receptor site to block the human cardiac sodium channel. PLoS One 2012; 7:e41667. [PMID: 22848561 PMCID: PMC3407203 DOI: 10.1371/journal.pone.0041667] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 06/23/2012] [Indexed: 12/24/2022] Open
Abstract
Bisphenol A (BPA) has attracted considerable public attention as it leaches from plastic used in food containers, is detectable in human fluids and recent epidemiologic studies link BPA exposure with diseases including cardiovascular disorders. As heart-toxicity may derive from modified cardiac electrophysiology, we investigated the interaction between BPA and hNav1.5, the predominant voltage-gated sodium channel subtype expressed in the human heart. Electrophysiology studies of heterologously-expressed hNav1.5 determined that BPA blocks the channel with a Kd of 25.4±1.3 µM. By comparing the effects of BPA and the local anesthetic mexiletine on wild type hNav1.5 and the F1760A mutant, we demonstrate that both compounds share an overlapping binding site. With a key binding determinant thus identified, an homology model of hNav1.5 was generated based on the recently-reported crystal structure of the bacterial voltage-gated sodium channel NavAb. Docking predictions position both ligands in a cavity delimited by F1760 and contiguous with the DIII–IV pore fenestration. Steered molecular dynamics simulations used to assess routes of ligand ingress indicate that the DIII–IV pore fenestration is a viable access pathway. Therefore BPA block of the human heart sodium channel involves the local anesthetic receptor and both BPA and mexiletine may enter the closed-state pore via membrane-located side fenestrations.
Collapse
Affiliation(s)
- Andrias O. O’Reilly
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Bavaria, Germany
- Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Esther Eberhardt
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Bavaria, Germany
| | - Christian Weidner
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Bavaria, Germany
- Bavarian Health and Food Safety Authority, Erlangen, Germany
| | - Christian Alzheimer
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Bavaria, Germany
| | - B. A. Wallace
- Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Angelika Lampert
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Bavaria, Germany
- * E-mail:
| |
Collapse
|
13
|
Sun H, Varela D, Chartier D, Ruben PC, Nattel S, Zamponi GW, Leblanc N. Differential interactions of Na+ channel toxins with T-type Ca2+ channels. ACTA ACUST UNITED AC 2008; 132:101-13. [PMID: 18591418 PMCID: PMC2442173 DOI: 10.1085/jgp.200709883] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Two types of voltage-dependent Ca2+ channels have been identified in heart: high (ICaL) and low (ICaT) voltage-activated Ca2+ channels. In guinea pig ventricular myocytes, low voltage–activated inward current consists of ICaT and a tetrodotoxin (TTX)-sensitive ICa component (ICa(TTX)). In this study, we reexamined the nature of low-threshold ICa in dog atrium, as well as whether it is affected by Na+ channel toxins. Ca2+ currents were recorded using the whole-cell patch clamp technique. In the absence of external Na+, a transient inward current activated near −50 mV, peaked at −30 mV, and reversed around +40 mV (HP = −90 mV). It was unaffected by 30 μM TTX or micromolar concentrations of external Na+, but was inhibited by 50 μM Ni2+ (by ∼90%) or 5 μM mibefradil (by ∼50%), consistent with the reported properties of ICaT. Addition of 30 μM TTX in the presence of Ni2+ increased the current approximately fourfold (41% of control), and shifted the dose–response curve of Ni2+ block to the right (IC50 from 7.6 to 30 μM). Saxitoxin (STX) at 1 μM abolished the current left in 50 μM Ni2+. In the absence of Ni2+, STX potently blocked ICaT (EC50 = 185 nM) and modestly reduced ICaL (EC50 = 1.6 μM). While TTX produced no direct effect on ICaT elicited by expression of hCaV3.1 and hCaV3.2 in HEK-293 cells, it significantly attenuated the block of this current by Ni2+ (IC50 increased to 550 μM Ni2+ for CaV3.1 and 15 μM Ni2+ for CaV3.2); in contrast, 30 μM TTX directly inhibited hCaV3.3-induced ICaT and the addition of 750 μM Ni2+ to the TTX-containing medium led to greater block of the current that was not significantly different than that produced by Ni2+ alone. 1 μM STX directly inhibited CaV3.1-, CaV3.2-, and CaV3.3-mediated ICaT but did not enhance the ability of Ni2+ to block these currents. These findings provide important new implications for our understanding of structure–function relationships of ICaT in heart, and further extend the hypothesis of a parallel evolution of Na+ and Ca2+ channels from an ancestor with common structural motifs.
Collapse
Affiliation(s)
- Hui Sun
- Excigen, Inc., Baltimore, MD 21224, USA
| | | | | | | | | | | | | |
Collapse
|
14
|
Edgerton GB, Blumenthal KM, Hanck DA. Evidence for multiple effects of ProTxII on activation gating in Na(V)1.5. Toxicon 2008; 52:489-500. [PMID: 18657562 DOI: 10.1016/j.toxicon.2008.06.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2008] [Revised: 06/11/2008] [Accepted: 06/23/2008] [Indexed: 11/26/2022]
Abstract
The peptide toxin ProTxII, recently isolated from the venom of the tarantula spider Thrixopelma pruriens, modifies gating in voltage-gated Na+ and Ca2+ channels. ProTxII is distinct from other known Na+ channel gating modifier toxins in that it affects activation, but not inactivation. It shifts activation gating positively and decreases current magnitude such that the dose-dependence of toxin action measured at a single potential reflects both effects. To test the extent to which these effects were independent, we tracked several different measures of current amplitude, voltage-dependent activation, and current kinetics in Na(V)1.5 in a range of toxin concentrations. Changes in voltage dependence and a decrease in G(max) appeared at relatively low concentrations (40-100 nM) while a positive shift in the voltage range of activation was apparent at higher toxin concentrations (> or =500 nM). Because ProTxII carries a net +4 charge we tested whether electrostatic interactions contributed to toxin action. We examined the effects of ProTxII in the presence of high extracellular Ba2+, known to screen and/or bind to surface charge. Some, but not all aspects of ProTxII modification were sensitive to the presence of Ba2+ indicating the contribution of an electrostatic, surface charge-like mechanism and supporting the idea of a multi-faceted toxin-channel interaction.
Collapse
Affiliation(s)
- Gabrielle B Edgerton
- Committee on Neurobiology, University of Chicago, 5841 South Maryland Avenue, MC6094, Chicago, IL 60637, USA
| | | | | |
Collapse
|
15
|
Proliferation of human lens epithelial cells (HLE-B3) is inhibited by blocking of voltage-gated calcium channels. Pflugers Arch 2008; 457:47-59. [DOI: 10.1007/s00424-008-0514-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 03/19/2008] [Accepted: 04/04/2008] [Indexed: 10/22/2022]
|
16
|
Clancy CE, Wehrens XHT. Mutation-specific effects of lidocaine in Brugada syndrome. Int J Cardiol 2007; 121:249-52. [PMID: 17761312 DOI: 10.1016/j.ijcard.2007.05.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 05/19/2007] [Indexed: 12/31/2022]
Abstract
Brugada syndrome (BrS) is a hereditary cardiac disease characterized by right bundle-branch block, an elevation of the ST-segment in leads V1 through V3 on the electrocardiogram, and ventricular fibrillation that can lead to sudden cardiac death. Mutations in the cardiac sodium channel gene SCN5A, which encodes the alpha-subunit of the human cardiac voltage-dependent Na+ channel (Na(v)1.5), are identified in 15-30% of patients with BrS. Most SCN5A mutations lead to a 'loss-of-function' phenotype, reducing the Na+ current during the early phases of the action potential. Anti-arrhythmic drugs that affect Na+ channels typically block these Na+ channels, thereby exaggerating the ECG abnormalities and arrhythmogenicity in the BrS. However, the N406S mutation in SCN5A causes distinct gating defects and enhanced intermediate inactivation of Na+ channels, which led to unexpected pharmacological effects of lidocaine in a patient carrying this mutation. In the presence of the N406S mutation, use-dependent block by lidocaine is reduced and recovery from intermediate inactivation is hastened by lidocaine. These findings suggest that lidocaine may improve the Brugada phenotype in patients with N406S by increasing the availability of Na+ channels.
Collapse
|
17
|
Sheets MF, Hanck DA. Outward stabilization of the S4 segments in domains III and IV enhances lidocaine block of sodium channels. J Physiol 2007; 582:317-34. [PMID: 17510181 PMCID: PMC2075305 DOI: 10.1113/jphysiol.2007.134262] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The anti-arrhythmic drug lidocaine has been shown to have a lower affinity for block of voltage-gated sodium channels at hyperpolarized potentials compared to depolarized potentials. Concomitantly, lidocaine reduces maximum gating charge (Qmax) by 40% resulting from the complete stabilization of the S4 in domain III in an outward, depolarized position and partial stabilization of the S4 in domain IV in wild-type Na+ channels (Na(V)1.5). To investigate whether the pre-positioning of the S4 segments in these two domains in a depolarized conformation increases affinity for lidocaine block, a cysteine residue was substituted for the 3rd outermost charged residue in the S4 of domain III (R3C-DIII) and for the 2nd outermost Arg in S4 of domain IV (R2C-DIV) in Na(V)1.5. After biotinylation by exposure to extracellular MTSEA-biotin the mutated S4s became stabilized in an outward, depolarized position. For Na+ channels containing both mutations (R3C-DIII + R2C-DIV) the IC50 for rested-state lidocaine block decreased from 194 +/- 15 microM in control to 28 +/- 2 microM after MTSEA-biotin modification. To determine whether an intact inactivation gate (formed by the linker between domains III and IV) was required for local anaesthetic drugs to modify Na+ channel gating currents, a Cys was substituted for the Phe in the IFM motif of the inactivation gate (ICM) and then modified by intracellular MTSET (WT-ICM(MTSET)) before exposure to intracellular QX-222, a quarternary amine. Although WT-ICM(MTSET) required higher concentrations of drug to block I(Na) compared to WT, Qmax decreased by 35% and the V1/2 shifted leftward as previously demonstrated for WT. The effect of stabilization of the S4s in domains III and IV in the absence of an intact inactivation gate on lidocaine block was determined for R3C-DIII + ICM, R2C-DIV + ICM and R3C-DIII + R2C-DIV + ICM, and compared to WT-ICM. IC50 values were 1360 +/- 430 microM, 890 +/- 70 microM, 670 +/- 30 microM and 1920 +/- 60 microM, respectively. Thermodynamic mutant-cycle analysis was consistent with additive (i.e. independent) contributions from stabilization of the individual S4s in R3C-DIII + ICM and R2C-DIV + ICM. We conclude that the positions of the S4s in domains III and IV are major determinants of the voltage dependence of lidocaine affinity.
Collapse
Affiliation(s)
- Michael F Sheets
- The Nora Eccles Harrison Cardiovascular Research & Training Institute and Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA.
| | | |
Collapse
|
18
|
McNulty MM, Edgerton GB, Shah RD, Hanck DA, Fozzard HA, Lipkind GM. Charge at the lidocaine binding site residue Phe-1759 affects permeation in human cardiac voltage-gated sodium channels. J Physiol 2007; 581:741-55. [PMID: 17363383 PMCID: PMC2075178 DOI: 10.1113/jphysiol.2007.130161] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Our homology molecular model of the open/inactivated state of the Na(+) channel pore predicts, based on extensive mutagenesis data, that the local anaesthetic lidocaine docks eccentrically below the selectivity filter, such that physical occlusion is incomplete. Electrostatic field calculations suggest that the drug's positively charged amine produces an electrostatic barrier to permeation. To test the effect of charge at this pore level on permeation in hNa(V)1.5 we replaced Phe-1759 of domain IVS6, the putative binding site for lidocaine's alkylamino end, with positively and negatively charged residues as well as the neutral cysteine and alanine. These mutations eliminated use-dependent lidocaine block with no effect on tonic/rested state block. Mutant whole cell currents were kinetically similar to wild type (WT). Single channel conductance (gamma) was reduced from WT in both F1759K (by 38%) and F1759R (by 18%). The negatively charged mutant F1759E increased gamma by 14%, as expected if the charge effect were electrostatic, although F1759D was like WT. None of the charged mutations affected Na(+)/K(+) selectivity. Calculation of difference electrostatic fields in the pore model predicted that lidocaine produced the largest positive electrostatic barrier, followed by lysine and arginine, respectively. Negatively charged glutamate and aspartate both lowered the barrier, with glutamate being more effective. Experimental data were in rank order agreement with the predicted changes in the energy profile. These results demonstrate that permeation rate is sensitive to the inner pore electrostatic field, and they are consistent with creation of an electrostatic barrier to ion permeation by lidocaine's charge.
Collapse
Affiliation(s)
- Megan M McNulty
- Cardiac Electrophysiology Laboratory, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | | | | | | | | | | |
Collapse
|