Search Results (219)

Background: Neuropathic pain remains difficult to treat because current analgesics often provide insufficient efficacy or dose-limiting adverse effects. Nav1.7 is genetically validated as a key regulator of human pain sensation, but the development of selective small-molecule Nav1.7 inhibitors has been limited by the high similarity among voltage-gated sodium channel subtypes. Methods: We generated monoclonal antibodies selectively targeting Nav1.7, humanized them for therapeutic development, and evaluated their binding, selectivity, functional channel inhibition, systemic analgesic efficacy, and effects on neuronal activity in a rat model of partial sciatic nerve ligation-induced neuropathic pain. Results: The humanized antibodies showed high-affinity and selective binding to Nav1.7 and functionally inhibited the channel in cellular assays. After systemic administration to neuropathic pain model rats, the lead antibody produced robust analgesia lasting at least 96 h. Electrophysiological analyses demonstrated reduced mechanically evoked and spontaneous neuronal activity, and immunohistochemistry showed decreased mechanical stimulus-induced phosphorylation of extracellular signal-regulated kinase in dorsal root ganglion neurons. The antibodies did not impair physiological nociception or motor function under the tested conditions. Conclusions: These findings provide preclinical proof of concept that humanized anti-Nav1.7 antibodies can act as systemically administered, long-acting biologic analgesics for neuropathic pain while preserving normal nociceptive and motor functions. The clinical advancement of S-151128 further supports the translational potential of this modality. Full article

Voltage-gated sodium channels are central to electrical excitability, and Nav1.7 is a major therapeutic target implicated in pain disorders and sensory signaling. Within the channel pore, permeating Na⁺ ions experience dynamically fluctuating hydration and coordination environments that may influence local ion–protein interactions. Identifying chemically distinct coordination states from molecular dynamics (MD) simulations is an important prerequisite for future higher-level electronic structure investigations. In this study, we present a reproducible workflow for identifying and classifying Na⁺ hydration–coordination microstates in the Nav1.7 pore using explicit-solvent molecular dynamics simulations. A geometrically defined pore region was used to quantify pore hydration and Na⁺ inner-shell coordination based on a 3.2 Å Na–O distance criterion. Na⁺ configurations were classified according to ligand identity into water-only (W), mixed protein–water (PW), and protein-only (P) microstates. Analysis of a 2 ns proof-of-principle simulation revealed a persistently hydrated pore environment, with Na⁺ coordination dominated by water-rich states and a smaller but distinct population of protein-contact configurations. These observations demonstrate that local coordination environments are chemically heterogeneous and cannot be fully described by hydration number alone. Representative structures from each microstate class were extracted to provide candidate configurations for future quantum mechanical, Quantum Mechanics/Molecular Mechanics (QM/MM), or density functional theory investigations of ion–ligand interactions in confined pore environments. The present work establishes a transparent and reproducible microstate-selection framework and does not report quantum mechanical energies, free-energy landscapes, or converged microstate populations. More broadly, the workflow provides a practical strategy for reducing complex MD ensembles into chemically interpretable coordination states suitable for subsequent higher-level analysis. Full article

Voltage-gated ion channels are central regulators of cardiac, neuronal, and skeletal muscle excitability, and their dysfunction underlies a wide spectrum of channelopathies, including arrhythmias and neuromuscular disorders. While conventional ion channel therapeutics typically target a single pore-binding site, emerging evidence supports the therapeutic potential of polypharmacological compounds capable of modulating multiple channel subtypes. ARumenamides represent a novel class of sulfonamide-based ligands originally identified as fenestration-targeting sodium channel modulators; however, their cross-family binding mechanisms and multitarget potential remain incompletely defined. Here, we employed an integrated structure-based computational workflow combining molecular docking, in silico ADMET profiling, and long-timescale (250 ns) molecular dynamics simulations to systematically evaluate 20 ARumenamide derivatives across 15 voltage-gated sodium, calcium, and potassium channel structures. Docking analyses revealed broad multitarget binding profiles, with several compounds exhibiting high predicted affinity across cardiac, neuronal, and skeletal muscle channel isoforms. ADMET predictions demonstrated favorable intestinal absorption and metabolic safety for most candidates, although solubility and mutagenicity liabilities were identified for select derivatives. Detailed molecular dynamics simulations of prioritized compounds (AR-310, AR-769, and AR-946) uncovered site-specific binding behaviors and conformational effects. AR-769 exhibited exceptional stability at both fenestration and central pore sites of Cav1.2, associated with persistent hydrogen-bond networks, reduced protein flexibility, and a well-defined free energy minimum. In contrast, AR-310 and AR-946 displayed selective stability within Nav1.4 fenestrations and the Kv4.3 central pore, respectively, highlighting how subtle chemical features bias binding site preference and dynamic retention. Collectively, these findings establish a structure–dynamics framework for rational design of ARumenamide-based multitarget ion channel modulators. Our results demonstrate that fenestration-focused binding can support sustained ligand engagement without obligatory pore occlusion, offering a mechanistically distinct strategy for developing next-generation polypharmacological therapeutics for cardiac and neuromuscular disorders. Full article

Human endometrial mesenchymal stem/stromal cells (eMSCs) are widely used in laboratories and clinical applications to study various aspects of tissue engineering and regenerative medicine. Three-dimensional (3D) cultivated MSCs have a higher therapeutic efficacy compared to 2D culture. Ion channels are involved in maintaining many physiological cell functions, including proliferation, differentiation, apoptosis, and migration. This study describes the functional expression of voltage-gated sodium channels (NaV) in eMSCs and the role of these channels in cell migration. Using RT-PCR analysis and immunofluorescent microscopy, we identified the expression of almost all pore-forming alpha (NaV 1.1, 1.2, 1.4–1.9) and channel-modulating beta-NaV subunits (except beta2) in eMSCs. In the whole-cell patch-clamp configuration, channels activated by membrane depolarization of eMSC were detected. The channels were blocked by the selective NaV antagonist TTX in nanomolar concentrations. The NaV agonist veratridine at a concentration of less than 40 μM inhibited voltage-gated sodium currents, while 100 μM and above prevented channel inactivation. The wound healing assay showed that both TTX (10 μM) and veratridine (100 μM) reduced the migration properties (the wound healing rate) of eMSCs cultivated in 2D conditions compared to the control. An opposite effect by both agents was shown on the motility of eMSCs cultivated in 3D conditions, increasing the cell spreading rate from spheroids. Our data suggest that NaV channels are expressed in human eMSCs and play an important role in the regulation of stem cell migration; this regulatory mechanism significantly depends on the culture conditions of MSCs. Full article

Dravet syndrome (DS) is a severe, catastrophic childhood epilepsy predominantly caused by loss-of-function mutations in the SCN1A gene, which encodes the voltage-gated sodium channel Na_v1.1. In this study, we evaluated the therapeutic potential of 5-(Benzofuran-2-yl)-3-(2-chloro-4-fluorobenzyl)-1,3,4-oxadiazol-2(3H)-one (GM-90663), a novel small molecule designed to address the complex pathophysiology of DS. Using scn1lab knockout (KO) zebrafish larvae—a robust vertebrate model for DS—we demonstrated that GM-90663 significantly alleviates seizure-like behavioral movements and rescues deficit in cognitive-like functions. Whole-cell patch-clamp recordings in hippocampal slices revealed that GM-90663 modulates voltage-gated Na⁺ channel kinetics; specifically, it suppresses slow ramp-induced currents, thereby effectively attenuating neuronal hyperexcitability. Furthermore, neurochemical profiling indicated that GM-90663 treatment leads to a marked increase in endogenous serotonin (5-HT) levels in both wild-type and KO larvae. Molecular docking simulations and subsequent in vitro enzymatic assays confirmed that this elevation in serotonin is mediated through the potent inhibition of monoamine oxidase (MAO) activity. Collectively, our findings suggest that GM-90663 exerts its anti-seizure effects through a synergistic dual mechanism—stabilizing sodium channel conductance and elevating serotonergic activity—positioning it as a promising multi-target candidate for the treatment of DS. Full article

Saxitoxin (STX) is one of the most potent natural neurotoxins known and is the only marine toxin to be declared a chemical weapon. In both marine and freshwater systems filter feeding organisms can accumulate saxitoxin and human consumption of toxin-contaminated food can result in paralytic shellfish poisoning. Here we highlight for the first time a human cell-based assay for the detection and neutralisation of STX activity on an automated patch clamp (APC) system. We demonstrate that a human embryonic kidney (HEK) cell line expressing human Nav1.6 can rapidly and sensitively detect the presence of a range of sodium ion channel blockers including STX. The use of neutralising monoclonal antibody GT13-A and/or saxiphilin was found to confer specificity to the assay by being able to dissociate between STX (along with closely related analogues) and tetrodotoxin. Finally, the application of the functional assay for the detection of STX in complex samples was evaluated during an international exercise led by the Organisation for the Prohibition of Chemical Weapons (OPCW). The neutralisation of STX activity in blinded samples enabled the indirect detection of the toxin in the relevant samples and provided an alternative orthogonal technique to corroborate the findings of liquid chromatography–mass spectrometry (LC-MS). Collectively this work demonstrates the significant potential for functional assays in the analysis of samples suspected of being contaminated with STX and related sodium ion channel targeting toxins; complementing traditional direct identification methods such as high-performance liquid chromatography with fluorescence detection (HPLC-FLD), LC-MS or enzyme-linked immunosorbent assay (ELISA). Full article

Scorpion neurotoxins are small peptides that target ion channels and offer opportunities for novel therapeutic discovery. This study analyzed the functional effects of the venom and toxins from the Costa Rican endemic scorpion, Tityus championi. Initially, crude venom was tested on different isoforms of voltage-gated sodium channels. Our findings revealed that the venom contains toxins that affect mammalian Na_V1.6 and Na_V1.7, as well as the cockroach BgNa_V1 channel. Increased currents through Na_V1.6 and BgNa_V1 channels were associated with bigger window currents and inhibition of inactivation. Decreased Na_V1.7 currents were associated with smaller conductance. Crude venom and TCh3 toxin inhibited action potential generation in invertebrate neurons expressing Na_V1.7-like channels. In these neurons, Tch2 and Tch4 toxins shifted voltage sensitivity to more negative potentials, ultimately widening the window current but decreasing channel availability. Conversely, Tch3 behaved as an inhibitory toxin, closing window currents and decreasing channel availability. Structural modeling showed that Tch3 adopts an αββ fold and binds the S3–S4 loop of Domain II in human Na_V1.7. These data show the diverse effects of scorpion venoms on channels and neurons, characterize its principal toxins, and show that Tch3 has therapeutic potential for pain relief. Full article

Dry eye disease (DED) is an ocular surface disorder characterized by tear film instability, inflammation, epithelial damage, and neurosensory abnormalities. Due to its multifactorial etiology and pathophysiology, conventional therapies that focus on lubrication and immunosuppression often fall short in addressing the neuropathic component of ocular pain experienced by a growing subset of patients. Recent developments in sensory neuroscience have highlighted the pivotal role of ion channels in mediating ocular surface homeostasis, pain signaling, and inflammation. This review examines the role of the following major ion channel families in the pathophysiology of DED and neuropathic ocular pain: transient receptor potential (TRP) channels, voltage-gated sodium (Nav) channels, and purinergic P2X receptors. The review details their anatomical distribution, molecular function, and responses to environmental stimuli such as heat, cold, osmolarity, and injury. Current treatments, such as artificial tears, anti-inflammatory drops, and systemic neuromodulators, are also reviewed in relation to their effects on ion channel modulation. Additionally, emerging therapies that directly target sensory transduction pathways are introduced. This review highlights the therapeutic potential of ion channel modulation in personalizing treatment for patients with ocular surface pain, particularly those with neuropathic features unresponsive to standard care. Full article

Background: Brugada syndrome (BrS) is a genetic cardiac arrhythmia disorder inherited in an autosomal dominant manner, characterized by ST-segment elevation in the right precordial leads (V1–V3) on electrocardiograms (ECGs). This syndrome predominantly affects young individuals with structurally normal hearts and significantly increases the risk of ventricular arrhythmias and sudden cardiac death (SCD). The most common genotype found among BrS patients is caused by variants in the SCN5A gene, which lead to a loss of function of the cardiac sodium channel Nav1.5 by different mechanisms. Methods: Plasmids containing SCN5A were constructed using PCR and site-directed mutagenesis to create the D372H variant. HEK293 cells were cultured and transfected with the WT, D372H, or a combination of both plasmids. Patch-clamp recordings assessed sodium current characteristics. Confocal microscopy visualized channel localization. Quantitative RT-PCR was used to analyze mRNA expression levels, while Western blot evaluated protein expression using specific antibodies. Results: In HEK293 cells expressing the D372H mutant, functional assays revealed a near-complete loss of sodium currents. Co-transfection of WT and D372H plasmids resulted in a significant reduction in current density compared with WT alone, while activation, inactivation, and recovery kinetics were unaffected. In addition, both the mutant protein and protein expressed in co-transfected cells exhibited reduced fluorescence intensity, indicating decreased expression levels. These findings were further supported by Western blot and RT-qPCR analyses. Conclusions: In summary, our findings indicate that the D372H variant produces a marked reduction in Nav1.5 function through reduced sodium current density and decreased channel expression. Given its critical position within the DI-pore loop, this defect is expected to markedly diminish the inward sodium current necessary for normal depolarization. Such impaired excitability—particularly relevant in the right ventricular outflow tract—may accentuate regional differences in repolarization and create conditions that favor reentrant activity. These findings provide mechanistic insights into how the p.D372H variant alters Nav1.5 channel function in vitro and offer functional evidence that may assist in interpreting its potential relevance to Brugada syndrome. Full article

Peptides from scorpion venom, mainly in species such as Olivierus martensii (formerly Olivierus martensii Karsch, often designated BMK) (BmK) and Tityus serrulatus from the Buthidae family, show real promise as painkillers that skip opioids altogether. They work by hitting specific ion channels and dialing down inflammation. This review gathers information on their molecular setups: disulfide-bridged types and those without, weighing in at 3 to 10 kilodaltons (kDa). Structural features include motifs stabilized by cysteines. In pain signaling, they block voltage-gated sodium channels (NaV) such as NaV1.7 and NaV1.8; take the BmK analgesic–antitumor peptide (BmK-AGAP) for example. Additionally, scorpion venom heat-resistant peptide (SVHRP) reduces microglia activity. Tests on rodents using formalin injections, acetic acid writhing, and chronic constriction injury (CCI) setups reveal pain relief that depends on dose and stacks up to morphine. Pairings like AGAP with lidocaine decrease the effective dose by half. In terms of safety, therapeutic levels have low-toxicity with a median lethal dose (LD50) over 20 mg/kg. Issues crop up with immune responses, unintended targets, and differences in venom batches. Clinical information remains thin, so gaps persist. Engineered versions could change the game for neuropathic pain, inflammatory conditions, and cancer-related discomfort. Standardization plus Phase I studies would help move this forward. Full article

Oxidative stress-induced lipid peroxidation products (LPPs), particularly 4-hydroxy-nonenal (4-HNE) and 4-oxo-nonenal (4-ONE), have recently gained attention for their direct regulation of ion channels essential for pain signaling. In this study, we investigated how these two LPPs affect the electrophysiological properties of neurons, specifically voltage-gated sodium (Na_V) channels, thereby influencing sensory neuron excitability and pain pathways. Using human neuroblastoma (SH-SY5Y) and ND7/23 cells (a fusion cell line exhibiting partial sensory neuron properties), we measured changes in Na_V channel-mediated sodium currents following treatment with 4-HNE or 4-ONE. Whole-cell patch-clamp experiments showed that 4-ONE (10 µM) and 4-HNE (100 µM) did not significantly alter the peak sodium current amplitude in SH-SY5Y cells. However, in ND7/23 cells, both 4-HNE and 4-ONE induced a negative shift in Na_V channel activation voltage dependence, enabling sodium channel activation at lower membrane potentials. Furthermore, current-clamp recordings in primary mouse dorsal root ganglion neurons demonstrated that treatment with 4-ONE and 4-HNE reduced the current threshold required to elicit action potentials and significantly increased action potential firing frequency. These findings indicate that LPPs enhance pain sensitivity by modulating Na_V channels, which play a crucial role in pain transmission. In conclusion, 4-HNE and 4-ONE shift the voltage-dependent activation of sodium channels toward more negative potentials, thereby increasing the excitability of primary sensory neurons and amplifying pain signals. This study provides molecular insights into how oxidative stress-related lipid peroxidation contributes to sensory mechanisms and offers potential avenues for developing new treatments for oxidative stress- or inflammation-associated pain. Full article

Pain is an unpleasant but essential sensory experience that serves as a protective mechanism, yet it can also manifest maladaptively in a wide range of pathological conditions. Current analgesic strategies rely heavily on opioid medications and non-steroidal anti-inflammatory drugs (NSAIDs); however, concerns regarding addiction, tolerance, and dose-limiting adverse effects highlight the urgent need for safer and more effective therapeutics. Voltage-gated sodium (Na_v) channels, which govern the initiation and propagation of action potentials, have emerged as promising targets for mechanism-based analgesic development. In particular, the Na_v1.7–Na_v1.9 subtypes have attracted substantial interest owing to their enrichment in the peripheral nervous system—despite broader expression elsewhere—and their central roles in nociception, offering the potential for non-addictive, subtype-selective pain modulation. This review summarizes the physiological roles of these channels in nociception, examines how disease-associated mutations shape pain phenotypes, and highlights recent advances in drug discovery targeting Na_v1.7 and Na_v1.8. The recent FDA approval of VX-548 (suzetrigine), a first-in-class and highly selective Na_v1.8 inhibitor, marks a major milestone that validates peripheral Na_v channels as clinically actionable targets for analgesia. We also discuss the remaining challenges and emerging opportunities in the pursuit of next-generation, mechanism-informed analgesics. Full article

Suzetrigine was approved by the US American Food and Drug Administration in 2025 as the first oral, non-opioid, selective inhibitor of Na_V1.8 sodium channel for the treatment of acute pain. Therefore, it represents a groundbreaking advancement in pain management. This review aims to provide an overview of the milestones in the medicinal-chemical development of Na_V1.8 inhibitors, eventually leading to suzetrigine. The multi-step synthesis route of suzetrigine is presented. Taking structural features into account, insights are provided into what plays a role for the inhibition of the Na_V1.8 channel. In addition, pharmacodynamic and pharmacokinetic aspects of the new drug, such as bioavailability, metabolism, and interaction with CYP450 enzymes, are discussed. A summary based on a large number of clinical trials demonstrating remarkable efficacy completes this comprehensive drug profile of suzetrigine, while also addressing limitations of the clinical trials and suggesting future perspectives. Full article

Dravet Syndrome (DS) is a severe genetic epileptic encephalopathy caused by mutations in the SCN1A gene that encodes the voltage-gated sodium channel (Na_V1.1) subunit alpha. DS is characterized by intractable seizures, progressive developmental delay, cognitive impairment, and high mortality due to sudden unexpected death in epilepsy (SUDEP). SUDEP is mediated by respiratory dysfunction, but the exact molecular underpinnings are unclear. Though hippocampal metabolic alterations have been reported in DS mice, such changes in brain regions controlling breathing have not been studied. We used Scn1a^A1783V/WT DS mice to study temporal alterations in the brain metabolome, including analysis of brainstem and forebrain regions. Glycolytic and pentose phosphate pathway intermediates were significantly elevated in the brainstem of DS mice during the period of enhanced susceptibility to mortality (post-natal days P20–30). In older P40–P50 mice, mitochondrial aconitate and the antioxidant glutathione were significantly elevated in the brainstem. Single-nuclei RNA sequencing (snRNA seq) and proteomic analyses revealed alterations in genes associated with neurotransmission, cellular respiration, and protein translation, as well as reorganization of protein kinase-mediated pathways that are specific to the brainstem. These findings suggest that there are widespread metabolic changes in the brainstem of DS mice. Full article

Scorpion venom toxins are important peptides being studied for their clinical significance. These peptides act by binding to ion channels in the membrane of nerve cells, causing the symptoms associated with scorpion stings (scorpionism). They principally affect the function of voltage-gated sodium channels (Nav) and are valuable for studying ion channels. Scorpions from the Buthidae family contain toxins that affect sodium channels and have a high affinity for mammalian channels. In this study, two sodium toxins isolated from the venom of the scorpion Centruroides hirsutipalpus, a member of the Buthidae family, were identified as belonging to the beta-type subfamily. These toxins were purified from whole venom using molecular exclusion, cationic-exchange, and reverse-phase chromatography techniques. Their molecular masses were determined using mass spectrometry, while their amino acid sequences were obtained by Edman degradation. A comparative analysis revealed that the sequences are identical to ChiNaBet60 and ChiNaBet50 toxins (now named Chirp7 and Chirp9, respectively) previously identified in the venom gland transcriptomics from C. hirsutipalpus. Furthermore, toxicity studies showed that these toxins were lethal to mammals. Electrophysiological analysis revealed that these peptides act as sodium channel–modulating toxins. In addition, interaction assays with antibodies were performed to analyze the structural determinants governing the binding mechanism. Full article