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Background and Aims Patients suffering from Brugada syndrome (BrS) are predisposed to life-threatening cardiac arrhythmias. Diagnosis is challenging due to the elusive electrocardiographic (ECG) signature that often requires unconventional ECG lead placement and drug challenges to be detected. Although NaV1.5 sodium channel dysfunction is a recognized pathophysiological mechanism in BrS, only 25% of patients have detectable SCN5A variants. Given the emerging role of autoimmunity in cardiac ion channel function, this study explores the presence and potential impact of anti-NaV1.5 autoantibodies in BrS patients. Methods Using engineered HEK293A cells expressing recombinant NaV1.5 protein, plasma from 50 BrS patients and 50 controls was screened for anti-NaV1.5 autoantibodies via western blot, with specificity confirmed by immunoprecipitation and immunofluorescence. The impact of these autoantibodies on sodium current density and their pathophysiological effects were assessed in cellular models and through plasma injection in wild-type mice. Results Anti-NaV1.5 autoantibodies were detected in 90% of BrS patients vs. 6% of controls, yielding a diagnostic area under the curve of.92, with 94% specificity and 90% sensitivity. These findings were consistent across varying patient demographics and independent of SCN5A mutation status. Electrophysiological studies demonstrated a significant reduction specifically in sodium current density. Notably, mice injected with BrS plasma showed Brugada-like ECG abnormalities, supporting the pathogenic role of these autoantibodies. Conclusions The study demonstrates the presence of anti-NaV1.5 autoantibodies in the majority of BrS patients, suggesting an immunopathogenic component of the syndrome beyond genetic predispositions. These autoantibodies, which could serve as additional diagnostic markers, also prompt reconsideration of the underlying mechanisms of BrS, as evidenced by their role in inducing the ECG signature of the syndrome in wild-type mice. These findings encourage a more comprehensive diagnostic approach and point to new avenues for therapeutic research. [ABSTRACT FROM AUTHOR]

Aims: To better understand the role of sodium channel beta subunit (SCNN1B) in the initiation and progression of colorectal cancer (CRC) and to identify potential biomarkers for the early detection and prognosis of CRC. Methods: A total of 74 pairs of CRC tissues and their adjacent normal tissues were collected between October 2016 and November 2017. The methylation levels of the SCNN1B promoter region in CRC tissues and their adjacent normal tissues were investigated by pyrosequencing. The expression of both SCNN1B mRNA and protein were detected by RT‒qPCR and immunohistochemistry, respectively. Results: The results showed that the methylation levels of the SCNN1B promoter region were significantly higher in CRC tissues than in adjacent normal tissues. The expression levels of SCNN1B mRNA and protein were significantly lower in the CRC tissues than in their adjacent normal tissues. Moreover, Pearson's correlation analysis showed that the methylation levels of the SCNN1B promoter were negatively correlated with the SCNN1B mRNA levels in CRC tissues. In addition, the high methylation levels and low mRNA expression of SCNN1B showed a significant association with advanced tumour stage, increased risk of lymph node metastasis and poor prognosis of CRC patients. Conclusion: This study suggested that the decreased expression of SCNN1B due to its promoter hypermethylation may play an important role in the progression and prognosis of CRC, and the methylation levels of the SCNN1B promoter may serve as an effective molecular marker for predicting the progression and prognosis of CRC. [ABSTRACT FROM AUTHOR]

Introduction: Resurgent current (INaR) generated by voltage-gated sodium channels (VGSCs) plays an essential role in maintaining high-frequency firing of many neurons and contributes to disease pathophysiology such as epilepsy and painful disorders. Targeting INaR may present a highly promising strategy in the treatment of these diseases. Navß4 and A-type fibroblast growth factor homologous factors (FHFs) have been identified as two classes of important INaR mediators; however, their receptor sites in VGSCs remain unknown, which hinders the development of novel agents to effectively target INaR. Methods: Navß4 and FHF4A can mediate INaR generation through the amino acid segment located in their C-terminus and N-terminus, respectively. We mainly employed site-directed mutagenesis, chimera construction and wholecell patch-clamp recording to explore the receptor sites of Navß4 peptide and FHF4A in Nav1.7 and Nav1.8. Results: We show that the receptor of Navß4-peptide involves four residues, N395, N945, F1737 and Y1744, in Nav1.7 DI-S6, DII-S6, and DIV-S6. We show that A-type FHFs generating INaR depends on the segment located at the very beginning, not at the distal end, of the FHF4 N-terminus domain. We show that the receptor site of A-type FHFs also resides in VGSC inner pore region. We further show that an asparagine at DIIS6, N891 in Nav1.8, is a major determinant of INaR generated by A-type FHFs in VGSCs. Discussion: Cryo-EM structures reveal that the side chains of the critical residues project into the VGSC channel pore. Our findings provide additional evidence that Navß4 peptide and A-type FHFs function as open-channel pore blockers and highlight channel inner pore region as a hotspot for development of novel agents targeting INaR. [ABSTRACT FROM AUTHOR]

In this work, we cloned and functionally expressed two novel GABAA receptor subunits from Procambarus clarkii crayfish. These two new subunits, PcGABAA‐α and PcGABAA‐β2, revealed significant sequence homology with the PcGABAA‐β subunit, previously identified in our laboratory. In addition, PcGABAA‐α subunit also shared a significant degree of identity with the Drosophila melanogaster genes DmGRD (GABA and glycine‐like receptor subunits of Drosophila) as well as PcGABAA‐β2 subunit with DmLCCH3 (ligand‐gated chloride channel homolog 3). Electrophysiological recordings showed that the expression in HEK cells of the novel subunits, either alone or in combination, failed to form functional homo‐ or heteromeric receptors. However, the co‐expression of PcGABAA‐α with PcGABAA‐β evoked sodium‐ or chloride‐dependent currents that accurately reproduced the time course of the GABA‐evoked currents in the X‐organ neurons from crayfish, suggesting that these GABA subunits combine to form two types of GABA receptors, one with cationic selectivity filter and the other preferentially permeates anions. On the other hand, PcGABAA‐β2 and PcGABAA‐β co‐expression generated a chloride current that does not show desensitization. Muscimol reproduced the time course of GABA‐evoked currents in all functional receptors, and picrotoxin blocked these currents; bicuculline did not block any of the recorded currents. Reverse transcription polymerae chain reaction (RT‐PCR) amplifications and FISH revealed that PcGABAA‐α and PcGABAA‐β2 are predominantly expressed in the crayfish nervous system. Altogether, these findings provide the first evidence of a neural GABA‐gated cationic channel in the crayfish, increasing our understanding of the role of these new GABAA receptor subunits in native heteromeric receptors. [ABSTRACT FROM AUTHOR]

In cystic fibrosis (CF), there is abnormal translocation and function of the cystic fibrosis transmembrane conductance regulator (CFTR) and an upregulation of the epithelial sodium channel (ENaC). This leads to hyperabsorption of sodium and fluid from the airway, dehydrated mucus, and an increased risk of respiratory infections. In this study, we performed a proteomic assessment of differentially regulated proteins from CF and non-CF small airway epithelial cells (SAEC) that are sensitive to Mycobacterium avium. CF SAEC and normal non-CF SAEC were infected with M. avium before the cells were harvested for protein. Protein kinase C (PKC) activity was greater in the CF cells compared to the non-CF cells, but the activity was significantly attenuated in both cell types after infection with M. avium compared to vehicle. Western blot and densitometric analysis showed a significant increase in cathepsin B protein expression in M. avium infected CF cells. Myristoylated alanine rich C-kinase substrate (MARCKS) protein was one of several differentially expressed proteins between the groups that was identified by mass spectrometry-based proteomics. Total MARCKS protein expression was greater in CF cells compared to non-CF cells. Phosphorylation of MARCKS at serine 163 was also greater in CF cells compared to non-CF cells after treating both groups of cells with M. avium. Taken together, MARCKS protein is upregulated in CF cells and there is decreased phosphorylation of the protein due to a decrease in PKC activity and presumably increased cathepsin B mediated proteolysis of the protein after M. avium infection. [ABSTRACT FROM AUTHOR]

Background and Purpose: Inhibitors of voltage‐gated sodium channels (NaVs) are important anti‐epileptic drugs, but the contribution of specific channel isoforms is unknown since available inhibitors are non‐selective. We aimed to create novel, isoform selective inhibitors of Nav channels as a means of informing the development of improved antiseizure drugs. Experimental Approach: We created a series of compounds with diverse selectivity profiles enabling block of NaV1.6 alone or together with NaV1.2. These novel NaV inhibitors were evaluated for their ability to inhibit electrically evoked seizures in mice with a heterozygous gain‐of‐function mutation (N1768D/+) in Scn8a (encoding NaV1.6) and in wild‐type mice. Key Results: Pharmacologic inhibition of NaV1.6 in Scn8aN1768D/+ mice prevented seizures evoked by a 6‐Hz shock. Inhibitors were also effective in a direct current maximal electroshock seizure assay in wild‐type mice. NaV1.6 inhibition correlated with efficacy in both models, even without inhibition of other CNS NaV isoforms. Conclusions and Implications: Our data suggest NaV1.6 inhibition is a driver of efficacy for NaV inhibitor anti‐seizure medicines. Sparing the NaV1.1 channels of inhibitory interneurons did not compromise efficacy. Selective NaV1.6 inhibitors may provide targeted therapies for human Scn8a developmental and epileptic encephalopathies and improved treatments for idiopathic epilepsies. [ABSTRACT FROM AUTHOR]

Schizophrenia is a leading cause of global disease burden. Current drug treatments are associated with significant side effects and have limited efficacy for many patients, highlighting the need to develop new approaches that target other aspects of the neurobiology of schizophrenia. Preclinical, in vivo imaging, postmortem, genetic, and pharmacological studies have highlighted the key role of cortical GABAergic (gamma-aminobutyric acidergic)-glutamatergic microcircuits and their projections to subcortical dopaminergic circuits in the pathoetiology of negative, cognitive, and psychotic symptoms. Antipsychotics primarily act downstream of the dopaminergic component of this circuit. However, multiple drugs are currently in development that could target other elements of this circuit to treat schizophrenia. These include drugs for GABAergic or glutamatergic targets, including glycine transporters, D-amino acid oxidase, sodium channels, or potassium channels. Other drugs in development are likely to primarily act on pathways that regulate the dopaminergic system, such as muscarinic or trace amine receptors or 5-HT 2A receptors, while PDE10A inhibitors are being developed to modulate the downstream consequences of dopaminergic dysfunction. Our review considers where new drugs may act on this circuit and their latest clinical trial evidence in terms of indication, efficacy, and side effects. Limitations of the circuit model, including whether there are neurobiologically distinct subgroups of patients, and future directions are also considered. Several drugs based on the mechanisms reviewed have promising clinical data, with the muscarinic agonist KarXT most advanced. If these drugs are approved for clinical use, they have the potential to revolutionize understanding of the pathophysiology and treatment of schizophrenia. [ABSTRACT FROM AUTHOR]

Microglia, the primary immune cells in the central nervous system, play a critical role in regulating neuronal function and fate through their interaction with neurons. Despite extensive research, the specific functions and mechanisms of microglia-neuron interactions remain incompletely understood. In this study, we demonstrate that microglia establish direct contact with myelinated axons at Nodes of Ranvier in the spinal cord of mice. The contact associated with neuronal activity occurs in a random scanning pattern. In response to axonal injury, microglia rapidly transform their contact into a robust wrapping form, preventing acute axonal degeneration from extending beyond the nodes. This wrapping behavior is dependent on the function of microglial P2Y12 receptors, which may be activated by ATP released through axonal volume-activated anion channels at the nodes. Additionally, voltage-gated sodium channels (NaV) and two-pore-domain potassium (K2P) channels contribute to the interaction between nodes and glial cells following injury, and inhibition of NaV delays axonal degeneration. Through in vivo imaging, our findings reveal a neuroprotective role of microglia during the acute phase of single spinal cord axon injury, achieved through neuron-glia interaction. The mechanisms underlying microglia-neuron interactions are incompletely understood. Utilizing in vivo multimodal microscopy and optical clearing technology, here the authors show a distinct neuroprotective function of microglia during the acute phase of a single spinal cord axon injury. [ABSTRACT FROM AUTHOR]

ABSTRACT A major insecticide resistance mechanism in insect pests is knock‐down resistance (kdr) caused by mutations in the voltage‐gated sodium channel (Vgsc) gene. Despite being common in most malaria Anopheles vector species, kdr mutations have never been observed in Anopheles funestus, the principal malaria vector in Eastern and Southern Africa, with resistance mainly being conferred by detoxification enzymes. In a parallel study, we monitored 10 populations of An. funestus in Tanzania for insecticide resistance unexpectedly identified resistance to a banned insecticide, DDT, in the Morogoro region. Through whole‐genome sequencing of 333 An. funestus samples from these populations, we found eight novel amino acid substitutions in the Vgsc gene, including the kdr variant, L976F (equivalent to L995F in An. gambiae), in tight linkage disequilibrium with another (P1842S). The mutants were found only at high frequency in one region and were accompanied by weak signatures of a selective sweep, with a significant decline between 2017 and 2023. Notably, kdr L976F was strongly associated with survivorship to exposure to DDT insecticide, while no clear association was noted with a pyrethroid insecticide (deltamethrin). The WHO prequalifies no DDT products for vector control, and the chemical is banned in Tanzania. Widespread DDT contamination and a legacy of extensive countrywide stockpiles may have selected for this mutation. Continued monitoring is necessary to understand the origin of kdr in An. funestus, and the threat posed to insecticide‐based vector control in Africa. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental Approach Key Results Conclusion and Implication KCNT1 encodes a sodium‐activated potassium channel (Slack channel), and its mutation can cause several forms of epilepsy. Traditional antiepileptic medications have limited efficacy in treating patients with KCNT1 mutations. Here, we describe one heterozygous KCNT1 mutation, M267T, in a patient with EIMFS. The pathological channel properties of this mutation and its effect on neuronal excitability were investigated. Additionally, this study aimed to develop a medication for effective prevention of KCNT1 mutation‐induced seizures.Wild‐type or mutant KCNT1 plasmids were expressed heterologously in Xenopus laevis oocytes, and channel property assessment and drug screening were performed based on two‐electrode voltage‐clamp recordings. The single‐channel properties were investigated using the excised inside‐out patches from HEK293T cells. Through in utero electroporation, WT and M267T Slack channels were expressed in the hippocampal CA1 pyramidal neurons in male mice, followed by the examination of the electrical properties using the whole‐cell current‐clamp technique. The kainic acid‐induced epilepsy model in male mice was used to evalute the antiseizure effects of carvedilol.The KCNT1 M267T mutation enhanced Slack channel function by increasing single‐channel open probability. Through screening 16 FDA‐approved ion channel blockers, we found that carvedilol effectively reversed the mutation‐induced gain‐of‐function channel properties. Notably, the KCNT1 M267T mutation in the mouse hippocampal CA1 pyramidal neurons affected afterhyperpolarization properties and induced neuronal hyperexcitability, which was inhibited by carvedilol. Additionally, carvedilol exhibited antiseizure effects in the kainic acid‐induced epilepsy model.Our findings suggest carvedilol as a new potential candidate for treatment of epilepsies. [ABSTRACT FROM AUTHOR]

Background: The Anopheles Hyrcanus group, which transmits Plasmodium vivax, consists of six confirmed species in South Korea. An epidemiological study revealed differences in the seasonal occurrence patterns of each species. Pyrethroid resistance in An. sinensis dates back to the early 2000s, whereas information on pyrethroid resistance in other species is lacking despite their greater significance in malaria epidemiology. Methods: Anopheles mosquitoes were collected from two malaria-endemic regions in South Korea for 2 years and their knockdown resistance (kdr) mutations were genotyped. The larval susceptibility to λ-cyhalothrin was compared in six Anopheles species and its seasonal changes in three species were investigated. The full-length sequences of the voltage-sensitive sodium channel (VSSC) were compared across six species to evaluate potential target-site insensitivity. The contribution of the kdr mutation to phenotypic resistance was confirmed by comparing median lethal time (LT50) to λ-cyhalothrin between populations of Anopheles belenrae with distinct genotypes. Results: The composition and seasonal occurrence of rare species (Anopheles kleini, Anopheles lestri, and Anopheles sineroides) varied considerably, whereas An. sinensis occurs continuously throughout the season. A kdr mutation in the form of heterozygous allele was newly identified in An. belenrae, An. lesteri, An. pullus, and An. sineroides. The baseline susceptibility to λ-cyhalothrin was the highest in An. belenrae, followed by An. lesteri, An. sineroides, An. kleini, An. pullus, and An. sinensis, with median lethal concentration (LC50) values ranging from 6.0- to 73.5-fold higher than that of An. belenrae. The susceptibility of An. sinensis and An. pullus varied by season, whereas that of An. belenrae remained stable. The kdr-heterozygous An. belenare population exhibited 5.1 times higher LT50 than that of the susceptible population. Species-specific VSSC sequence differences were observed among the six species. Conclusions: Our findings suggest that the status and extent of pyrethroid resistance vary among Anopheles Hyrcanus group species. While An. sinensis, the predominant species, developed a considerable level of pyrethroid resistance through kdr mutation, the resistance levels of other species appeared to be less pronounced. Large-scale monitoring is crucial to fully understand species-specific seasonal occurrence and resistance status for effective management strategies, considering the ongoing impact of climate change on their vectorial capacity. [ABSTRACT FROM AUTHOR]

For >30 years, the Eilat Conference on New Antiepileptic Drugs and Devices has provided a forum for the discussion of advances in the development of new therapies for seizures and epilepsy. The EILAT XVII conference took place in Madrid, Spain, on May 5–8, 2024. Participants included basic scientists and clinical investigators from industry and academia, other health care professionals, and representatives from lay organizations. We summarize in this article information on treatments in preclinical and in early clinical development discussed at the conference. These include AMT‐260, a gene therapy designed to downregulate the expression of Glu2K subunits of kainate receptors, in development for the treatment of drug‐resistant seizures associated with mesial temporal sclerosis; BHV‐7000, a selective activator of heteromeric Kv7.2/7.3 potassium channels, in development for the treatment of focal epilepsy; ETX101, a recombinant adeno‐associated virus serotype 9 designed to increase NaV1.1 channel density in inhibitory γ‐aminobutyric acidergic (GABAergic) neurons, in development for the treatment of SCN1A‐positive Dravet syndrome; GAO‐3‐02, a compound structurally related to synaptamide, which exerts antiseizure activity at least in part through an action on cannabinoid type 2 receptors; LRP‐661, a structural analogue of cannabidiol, in development for the treatment of seizures associated with Lennox–Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex; OV329, a selective inactivator of GABA aminotransferase, in development for the treatment of drug‐resistant seizures; PRAX‐628, a functionally selective potent sodium channel modulator with preference for the hyperexcitable state of sodium channels, in development for the treatment of focal seizures; RAP‐219, a selective negative allosteric modulator of transmembrane α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor regulatory protein γ‐8, in development for the treatment of focal seizures; and rozanolixizumab, a humanized anti‐neonatal Fc receptor monoclonal antibody, in development for the treatment of LGI1 autoimmune encephalitis. Treatments in more advanced development are summarized in Part II of this report. [ABSTRACT FROM AUTHOR]

Animals that consume toxic diets provide models for understanding the molecular and physiological adaptations to ecological challenges. Garter snakes (Thamnophis) in western North America prey on Pacific newts (Taricha), which employ tetrodotoxin (TTX) as an antipredator defense. These snakes possess mutations in voltage-gated sodium channels (Nav), the molecular targets of TTX, that decrease the binding ability of TTX to sodium channels (target-site resistance). However, genetic variation at these loci that cannot explain all the phenotypic variation in TTX resistance in Thamnophis. We explored a separate means of resistance, toxin metabolism, to determine if TTX-resistant snakes either rapidly remove TTX or sequester TTX. We examined the metabolism and distribution of TTX in the body (toxicokinetics), to determine differences between TTX-resistant and TTX-sensitive snakes in the rates at which TTX is eliminated from organs and the whole body (using TTX half-life as our metric). We assayed TTX half-life in snakes from TTX-resistant and TTX-sensitive populations of three garter snake species with a coevolutionary history with newts (T. atratus, T. couchii, T. sirtalis), as well as two non-resistant "outgroup" species (T. elegans, Pituophis catenifer) that seldom (if ever) engage newts. We found TTX half-life varied across species, populations, and tissues. Interestingly, TTX half-life was shortest in T. elegans and P. catenifer compared to all other snakes. Furthermore, TTX-resistant populations of T. couchii and T. sirtalis eliminated TTX faster (shorter TTX half-life) than their TTX-sensitive counterparts, while populations of TTX-resistant and TTX-sensitive T. atratus showed no difference rates of TTX removal (same TTX half-life). The ability to rapidly eliminate TTX may have permitted increased prey consumption, which may have promoted the evolution of additional resistance mechanisms. Finally, snakes still retain substantial amounts of TTX, and we projected that snakes could be dangerous to their own predators days to weeks following the ingestion of a single newt. Thus, aspects of toxin metabolism may have been key in driving predator–prey relationships, and important in determining other ecological interactions. [ABSTRACT FROM AUTHOR]

Non-excitable cells express sodium voltage-gated channel alpha subunit 1 gene and protein (known as SCN1A and NaV 1.1, respectively); however, the functions of NaV 1.1 are unclear. In this study, we investigated the role of SCN1A and NaV 1.1 in human mesenchymal stem cells (MSCs). We found that SCN1A was expressed in MSCs, and abundant expression of NaV 1.1 was observed in the endoplasmic reticulum; however, this expression was not found to be related to Na+ currents. SCN1A-silencing reduced MSC proliferation and delayed the cell cycle in the S phase. SCN1A silencing also suppressed the protein levels of CDK2 and AKT (herein referring to total AKT), despite similar mRNA expression, and inhibited AKT phosphorylation in MSCs. A cycloheximide-chase assay showed that SCN1A-silencing induced CDK2 but not AKT protein degradation in MSCs. A proteolysis inhibition assay using epoxomicin, bafilomycin A1 and NH4 Cl revealed that both the ubiquitin–proteasome system and the autophagy and endo- lysosome system were irrelevant to CDK2 and AKT protein reduction in SCN1A-silenced MSCs. The AKT inhibitor LY294002 did not affect the degradation and nuclear localization of CDK2 in MSCs. Likewise, the AKT activator SC79 did not attenuate the SCN1A-silencing effects on CDK2 in MSCs. These results suggest that NaV 1.1 contributes to the cell cycle of MSCs by regulating the post-translational control of AKT and CDK2. [ABSTRACT FROM AUTHOR]

Quinoline-related antimalarial drugs have been associated with cardiotoxicity risk, in particular QT prolongation and QRS complex widening. In collaboration with Medicines for Malaria Venture, we discovered novel plasmepsin X (PMX) inhibitors for malaria treatment. The first lead compounds tested in anesthetized guinea pigs (GPs) induced profound QRS widening, although exhibiting weak inhibition of NaV1.5-mediated currents in standard patch clamp assays. To understand the mechanism(s) underlying QRS widening to identify further compounds devoid of such liability, we established a set of in vitro models including CaV1.2, NaV1.5 rate-dependence, and NaV1.8 patch clamp assays, human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), and Langendorff-perfused isolated GP hearts. Six compounds were tested in all models including anesthetized GP, and 8 additional compounds were tested in vitro only. All compounds tested in anesthetized GP and isolated hearts showed a similar cardiovascular profile, consisting of QRS widening, bradycardia, negative inotropy, hypotension, and for some, QT prolongation. However, a left shift of the concentration–response curves was noted from in vitro to in vivo GP data. When comparing in vitro models, there was a good consistency between decrease in sodium spike amplitude in hiPSC-CM and QRS widening in isolated hearts. Patch clamp assay results showed that the QRS widening observed with PMX inhibitors is likely multifactorial, primarily due to NaV1.8 and NaV1.5 rate-dependent sodium blockade and/or calcium channel-mediated mechanisms. In conclusion, early de-risking of QRS widening using a set of different in vitro assays allowed to identify novel PMX inhibitors with improved cardiac safety profile. [ABSTRACT FROM AUTHOR]

Cystic fibrosis (CF) is a genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, resulting in defective chloride ion channels. This leads to thick, dehydrated mucus that severely disrupts mucociliary clearance in the respiratory system and triggers infection that eventually is the cause of death of CF patients. Current therapeutic strategies primarily focus on restoring CFTR function, blocking epithelial sodium channels to prevent mucus dehydration, or directly targeting mucus to reduce its viscosity. Among the ion channels expressed in ciliated bronchial epithelial cells, the transient receptor potential vanilloid 4 (TRPV4) channel emerges as a significant channel in CF pathogenesis. Activation of TRPV4 channels affects the regulation of airway surface liquid by modulating sodium absorption and intracellular calcium levels, which indirectly influences CFTR activity. TRPV4 is also involved in the regulatory volume decrease (RVD) process and enhances inflammatory responses in CF patients. Here, we combine current findings on TRPV4 channel modulation as a promising therapeutic approach for CF. Although limited studies have directly explored TRPV4 in CF, emerging evidence indicates that TRPV4 activation can significantly impact key pathological processes in the disease. Further investigation into TRPV4 modulators could lead to innovative treatments that alleviate severe respiratory complications and improve outcomes for CF patients. [ABSTRACT FROM AUTHOR]

The use of insecticides, primarily pyrethroids, is a pivotal strategy for mosquito control globally. Bioallethrin, the first commercially available volatile pyrethroid, can elicit spatial (i.e., noncontact) repellency to mosquitoes through the coactivation of olfactory receptor neurons and sodium channels. However, the olfactory mechanism of the repellency elicited by bioallethrin in mosquitoes is still unclear. Here, we demonstrated the involvement of AsOBP1 in the bioallethrin repellency in Anopheles sinensis, one of the main vectors of vivax malaria in China and other Southeast Asian countries. The behavioral and electrophysiological analyses in AsOrco−/− mutant found that the spatial repellency elicited by bioallethrin depended on the odorant receptor (OR)‐mediated olfactory pathway. Furthermore, the repellency was reduced in the AsOBP1−/− mutant and a pyrethroid‐resistant strain, in which the expression of AsOBP1 was significantly decreased. Moreover, recombinant AsOBP1 protein bound to bioallethrin in an in vitro competition assay. These results indicate that activation of the AsOBP1‐mediated olfactory pathway is an important component of bioallethrin repellency. Our research lays the foundation for further elucidation into the olfactory mechanism of bioallethrin repellency and the behavioral modifications of pyrethroid‐resistant mosquitoes. [ABSTRACT FROM AUTHOR]

Practical Application T‐2 toxin is a member of class A aspergilloides toxins, one of the most prevalent mycotoxins that contaminate feed and food. Direct ingestion of animals or feed contaminated by T‐2 toxin can cause various animal diseases. Butyrate is an organic fatty acid featuring a four‐carbon chain, which is commonly found in the form of sodium butyrate (NaB). NaB has several biological functions and pharmacological effects. However, the role of sodium butyrate in alleviating T‐2 toxin–induced hepatorenal toxicity has not been explored. In this study, 240 juvenile quails were evenly assigned into 4 groups. The experimental setup comprised four groups: The control group received a standard diet; the toxin group received a diet containing 0.9 mg/kg T‐2 toxin; the butyrate group received a diet containing 0.5 g/kg NaB; and the T‐2 treatment group received a diet containing both 0.9 mg/kg T‐2 toxin and 0.5 g/kg NaB. We evaluated the histopathological changes in the kidney and liver on Days 14 and 28 and explored the molecular mechanisms involving oxidative stress, inflammation, and expression of nuclear xenobiotic receptors (NXRs). Our results showed that T‐2 toxin exposure–induced inflammation in the liver and kidney by activating the oxidative stress pathway and modulating expression of NXRs to regulate related CYP450 isoforms, ultimately leading to histopathological injury in the liver and kidney, whereas sodium butyrate ameliorated this injury. These results offer novel insights into the molecular mechanisms underlying the protective effects of sodium butyrate in mitigating T‐2 toxin–induced hepatorenal injury in juvenile quails.The mechanisms of T‐2 toxin toxicity have been well described in experimental animals, but studies in birds are limited. With the development of society, the market scale of quails farming has been expanding, and the value of quails meat and eggs is increasing; there is an urgent need to clarify the harm of T‐2 toxin to quails and its mechanism. [ABSTRACT FROM AUTHOR]

Background: Clinical trials have shown that cenobamate (CNB) is an efficacious and safe anti-seizure medication (ASM) for drug-resistant focal epilepsy. Here, we analyzed one of the largest real-world cohorts, covering the entire spectrum of epilepsy syndromes, the efficacy and safety of CNB, and resulting changes in concomitant ASMs. Methods: We conducted a retrospective observational study investigating CNB usage in two German tertiary referral centers between October 2020 and June 2023 with follow-up data up to 27 months of treatment. Our primary outcome was treatment response. Secondary outcomes comprised drug response after 12 and 18 months, seizure freedom rates, CNB dosage and retention, adverse drug reactions (ADRs), and changes in concomitant ASMs. Results: 116 patients received CNB for at least two weeks. At 6 months, 98 patients were eligible for evaluation. Thereof 50% (49/98) were responders with no relevant change at 12 and 18 months. Seizure freedom was achieved in 18.4% (18/98) at 6 months, 16.7% (11/66), and 3.0% (1/33) at 12 and 18 months. The number of previous ASMs did not affect the seizure response rate. Overall, CNB was well-tolerated, however, in 7.7% (9/116), ADRs led to treatment discontinuation. The most frequent changes of concomitant ASMs included the discontinuation or reduction of sodium channel inhibitors, clobazam reduction, and perampanel discontinuation, while brivaracetam doses were usually left unchanged. Conclusions: CNB proved to be a highly effective and generally well-tolerated ASM in patients with severe drug-resistant epilepsy, comprising a broad array of epilepsy syndromes beyond focal epilepsy. [ABSTRACT FROM AUTHOR]

Phantom Limb Syndrome (PLS) can be defined as the disabling or painful sensation of the presence of a body part that is no longer present after its amputation. Anatomical changes involved in Phantom Limb Syndrome, occurring at peripheral, spinal and brain levels and include the formation of neuromas and scars, dorsal horn sensitization and plasticity, short-term and long-term modifications at molecular and topographical levels. The molecular reorganization processes of Phantom Limb Syndrome include NMDA receptors hyperactivation in the dorsal horn of the spinal column leading to inflammatory mechanisms both at a peripheral and central level. At the brain level, a central role has been recognized for sodium channels, BDNF and adenosine triphosphate receptors. In the paper we discuss current available pharmacological options with a final overview on non-pharmacological options in the pipeline. [ABSTRACT FROM AUTHOR]

The document "Drug Repurposing Patent Applications: April–June 2024" explores various drug repurposing patent applications, highlighting the potential of repurposed drugs in treating a wide range of conditions. Examples include treprostinil for enhancing the killing of Mycobacterium abscessus, lapaquistat for intestinal infections, and rabeprazole for inhibiting aortic valve calcification. The document also discusses the therapeutic applications of compounds like bupivacaine, fenofibrate, flibanserin, propofol, and methylene blue in different medical conditions, showcasing the versatility of repurposed drugs in addressing diverse health issues. [Extracted from the article]

BACKGROUND: Dermanyssus gallinae, the poultry red mite (PRM), is a worldwide ectoparasite posing significant economic challenges in poultry farming. The extensive use of pyrethroids for PRM control has led to the emergence of pyrethroid resistance. The objective of this study is to detect the pyrethroid resistance and explore its associated point mutations in the voltage‐gated sodium channel (VGSC) gene among PRM populations in China. RESULTS: Several populations of D. gallinae, namely CJF‐1, CJP‐2, CJP‐3, CSD‐4 and CLD‐5, displayed varying degrees of resistance to beta‐cypermethrin compared to a susceptible field population (CBP‐5). Mutations of VGSC gene in populations of PRMs associated with pyrethroid resistance were identified through sequencing its fragments IIS4–IIS5 and IIIS6. The mutations I917V, M918T/L, A924G and L925V were present in multiple populations, while no mutations were found at positions T929, I936, F1534 and F1538. CONCLUSION: The present study confirmed the presence of extremely high levels of pyrethroid resistance in PRM populations in China, and for the first time detected four pyrethroid resistance mutations in the VGSC gene. Identifying pyrethroid resistance in the field population of PRM in China can be achieved through screening for VGSC gene mutations as an early detection method. Our findings underscore the importance of implementing chemical PRM control strategies based on resistance evidence, while also considering the management of acaricide resistance in the control of PRMs. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion Familial hemiplegic migraine (FHM) is a rare subtype of migraine with aura. Variants in calcium voltage‐gated channel subunit alpha1 A (CACNA1A), ATPase Na+/K+ transporting subunit alpha 2 (ATP1A2), and sodium voltage‐gated channel alpha subunit 1 (SCN1A) genes have a well‐established association with the development of FHM. Recent studies suggest that other genes may also have a significant role in the pathogenesis of FHM, including proline‐rich transmembrane protein 2 (PRRT2). To our knowledge, there are currently no documented reports of the use of monoclonal antibodies targeting calcitonin gene‐related peptide in FHM caused by a specific identified genetic mutation – and in particular not in FHM associated with PRRT2 mutations. The aim of our work is to describe the efficacy of galcanezumab as a prophylaxis treatment on patients from an Italian family consisting of six patient carriers of a PRRT2 pathogenic variant.Inclusion criteria for treatment eligibility consisted of a confirmed diagnosis of genetically confirmed FHM as defined by the International Classification of Headache Disorders, third edition, number of headache days/month ≥4, and at least two previously failed migraine prophylaxis treatments. We evaluated clinical data of patients treated with galcanezumab regarding number of headache days/month, frequency of aura, disability caused by HM using the Migraine Disability Assessment (MIDAS), attack severity through a numerical rating scale (NRS), acute medications intake, and response to acute medications at baseline (t0) and after 3 (t1) and 6 (t2) months of treatment.Three out of six family members met inclusion criteria for treatment with galcanezumab. The average number of headache days/month, acute medications, and MIDAS significantly decreased in all treated patients, as well as the average NRS score. Aura frequency reduced by ≥50% compared to the baseline in all three patients. No adverse events related to galcanezumab were reported.Galcanezumab is a valid and well‐tolerated treatment option in PRRT2‐associated FHM. [ABSTRACT FROM AUTHOR]

Background: Insecticide resistance poses a significant challenge in the implementation of vector-borne disease control strategies. We have assessed the resistance levels of Aedes albopictus to deltamethrin and pyriproxyfen (PPF) in Fujian Province (China) and investigated the correlation between these resistance levels and mutations in the voltage-gated sodium channel (VGSC). Methods: The WHO bioassay protocol was used to evaluate the resistance coefficient of Ae. albopictus to deltamethrin and PPF, comparing a susceptible population from the Foshan (FS) area with wild populations from the Sanming (SM), Quanzhou (QZ), Zhangzhou (ZZ), Putian (PT) and Fuzhou (FZ) areas in Fujian Province. Genomic DNA was analyzed by PCR and sequencing to detect knockdown resistance (kdr) in the VGSC, specifically at the pyrethroid resistance alleles V1016V, I1532I and F1534F. Molecular docking was also performed to analyze the binding interactions of PPF and its metabolite 4'-OH-PPF to cytochrome P450 (CYP) 2C19, 2C9 and 3A4 and Ae. albopictus methoprene-tolerant receptors (AeMet), respectively. Results: The analysis of resistance to deltamethrin and PPF among Ae. albopictus populations from the various regions revealed that except for the sensitive population in FS and the SM population, the remaining four regional populations demonstrated resistance levels ranging from 4.31- to 18.87-fold for deltamethrin and from 2.85– to 3.62-fold for PPF. Specifically, the FZ and PT populations exhibited high resistance to deltamethrin, whereas the ZZ and QZ populations approached moderate resistance levels. Also, the resistance of the FZ, PT and ZZ populations to PPF increased slowly but consistently with the increasing trend of deltamethrin resistance. Genomic analysis identified multiple non-synonymous mutations within the VGSC gene; the F1534S and F1534L mutations showed significant resistance to deltamethrin in Ae. albopictus. Molecular docking results revealed that PPF and its metabolite 4'-OH-PPF bind to the Ae. albopictus AeMet receptor and CYP2C19. Conclusions: The wild Ae. albopictus populations of Fujian Province showed varying degrees of resistance to deltamethrin and PPF and a trend of cross-resistance to deltamethrin and PPF. Increased vigilance is needed for potential higher levels of cross-resistance, especially in the PT and FZ regions. [ABSTRACT FROM AUTHOR]

Neuronal hyperexcitability is a key element of many neurodegenerative disorders including the motor neuron disease Amyotrophic Lateral Sclerosis (ALS), where it occurs associated with elevated late sodium current (INaL). INaL results from incomplete inactivation of voltage-gated sodium channels (VGSCs) after their opening and shapes physiological membrane excitability. However, dysfunctional increases can cause hyperexcitability-associated diseases. Here we reveal the atypical binding mechanism which explains how the neuroprotective ALS-treatment drug riluzole stabilises VGSCs in their inactivated state to cause the suppression of INaL that leads to reversed cellular overexcitability. Riluzole accumulates in the membrane and enters VGSCs through openings to their membrane-accessible fenestrations. Riluzole binds within these fenestrations to stabilise the inactivated channel state, allowing for the selective allosteric inhibition of INaL without the physical block of Na+ conduction associated with traditional channel pore binding VGSC drugs. We further demonstrate that riluzole can reproduce these effects on a disease variant of the non-neuronal VGSC isoform Nav1.4, where pathologically increased INaL is caused directly by mutation. Overall, we identify a model for VGSC inhibition that produces effects consistent with the inhibitory action of riluzole observed in models of ALS. Our findings will aid future drug design and supports research directed towards riluzole repurposing. The authors here present a high-resolution structure of riluzole bound to a voltage-gated sodium channel. This identifies an intramembranous drug-binding site allowing the potent riluzole-induced enhancement of channel inactivation, normalising the hyperexcitable cellular states found in ALS models. This supports riluzole repurposing and aids future drug design efforts. [ABSTRACT FROM AUTHOR]

The δ‐conotoxins, a class of peptides produced in the venom of cone snails, are of interest due to their ability to inhibit the inactivation of voltage‐gated sodium channels causing paralysis and other neurological responses, but difficulties in their isolation and synthesis have made structural characterization challenging. Taking advantage of recent breakthroughs in computational algorithms for structure prediction that have made modeling especially useful when experimental data is sparse, this work uses both the deep‐learning‐based algorithm AlphaFold and comparative modeling method RosettaCM to model and analyze 18 previously uncharacterized δ‐conotoxins derived from piscivorous, vermivorous, and molluscivorous cone snails. The models provide useful insights into the structural aspects of these peptides and suggest features likely to be significant in influencing their binding and different pharmacological activities against their targets, with implications for drug development. Additionally, the described protocol provides a roadmap for the modeling of similar disulfide‐rich peptides by these complementary methods. [ABSTRACT FROM AUTHOR]

Many neurons in the mammalian brain show pacemaking activity: rhythmic generation of action potentials in the absence of sensory or synaptic input. Slow pacemaking of neurons releasing modulatory transmitters is easy to rationalize. More surprisingly, many neurons in the motor system also show pacemaking activity, often rapid, including cerebellar Purkinje neurons that fire spontaneously at 20–100 Hz, as well as key neurons in the basal ganglia, including subthalamic nucleus neurons and globus pallidus neurons. Although the spontaneous rhythmic firing of pacemaking neurons is phenomenologically similar to cardiac pacemaking, the underlying ionic mechanism in most neurons is quite different than for cardiac pacemaking. Few spontaneously active neurons rely on HCN ‘pacemaker’ channels for their activity. Most commonly, a central element is ‘persistent’ sodium current, steady‐state subthreshold current carried by the same voltage‐dependent sodium channels that underlie fast action potentials. Persistent sodium current is a steeply voltage‐dependent current with a midpoint near −60 mV, which results in regenerative spontaneous depolarization once it produces a net inward current when summed with all other background currents, often at voltages as negative as −70 mV. This ‘engine’ of pacemaking is present in almost all neurons and must be held in check in non‐pacemaking neurons by sufficiently large competing outward currents from background potassium channels. The intrinsic propensity of neurons to fire spontaneously underlies key normal functions such as respiration and generates the complex background oscillatory circuits revealed in EEGs, but can also produce out‐of‐control oscillations of overall brain function in epilepsy, ataxia and tremor. [ABSTRACT FROM AUTHOR]

Background: Intensive deployment of insecticide based malaria vector control tools resulted in the rapid evolution of phenotypes resistant to these chemicals. Understanding this process at the genomic level is important for the deployment of successful vector control interventions. Therefore, longitudinal sampling followed by whole genome sequencing (WGS) is necessary to understand how these evolutionary processes evolve over time. This study investigated the change in genetic structure and the evolution of the insecticide resistance variants in natural populations of Anopheles gambiae over time and space from 2012 to 2017 in Burkina Faso. Methods: New genomic data have been generated from An. gambiae mosquitoes collected from three villages in the western part of Burkina Faso between 2012 and 2017. The samples were whole-genome sequenced and the data used in the An. gambiae 1000 genomes (Ag1000G) project as part of the Vector Observatory. Genomic data were analysed using the analysis pipeline previously designed by the Ag1000G project. Results: The results showed similar and consistent nucleotide diversity and negative Tajima's D between An. gambiae sensu stricto (s.s.) and Anopheles coluzzii. Principal component analysis (PCA) and the fixation index (FST) showed a clear genetic structure in the An. gambiae sensu lato (s.l.) species. Genome-wide FST and H12 scans identified genomic regions under divergent selection that may have implications in the adaptation to ecological changes. Novel voltage-gated sodium channel pyrethroid resistance target-site alleles (V402L, I1527T) were identified at increasing frequencies alongside the established alleles (Vgsc-L995F, Vgsc-L995S and N1570Y) within the An. gambiae s.l. populations. Organophosphate metabolic resistance markers were also identified, at increasing frequencies, within the An. gambiae s.s. populations from 2012 to 2017, including the SNP Ace1-G280S and its associated duplication. Variants simultaneously identified in the same vector populations raise concerns about the long-term efficacy of new generation bed nets and the recently organophosphate pirimiphos-methyl indoor residual spraying in Burkina Faso. Conclusion: These findings highlighted the benefit of genomic surveillance of malaria vectors for the detection of new insecticide resistance variants, the monitoring of the existing resistance variants, and also to get insights into the evolutionary processes driving insecticide resistance. [ABSTRACT FROM AUTHOR]

Background: Scabies is a prevalent dermatological condition with significant public health implications. The recent rise in drug-resistant scabies presents new challenges for effective disease management and control. Methods: A comprehensive literature review was conducted using PubMed, Cochrane Library, and Web of Science. Studies published from 2000 to August 2024 were considered, focusing on those reporting drug-resistant scabies and advancements in treatment approaches. Results: Clinical studies, in vitro investigations, and case reports show significant resistance of human scabies to permethrin. Main resistance mechanisms involve genetic mutations in the mites' voltage-gated sodium channels (VGSCs) and enhanced activity or expression of the detoxifying enzyme glutathione S-transferase (GST). Resistance to ivermectin and benzyle benzoate, although suggested by some authors, seems less obvious. The clinical evidence of widespread ivermectin resistance in human scabies infestations is lacking, despite indications of increased tolerance in laboratory settings and anecdotal reports of resistance in patients with crusted scabies. Benzyl benzoate resistance in scabies mites remains unconfirmed. Conclusions: Permethrin-resistant scabies is an escalating threat requiring new management strategies and updated guidelines. Infection control measures, alternative treatments, and ongoing research into new therapeutics are crucial to mitigate the impact of drug-resistant scabies. [ABSTRACT FROM AUTHOR]

The development of therapeutic strategies to reduce impairments following spinal cord injury (SCI) motivates an active area of research, because there are no effective therapies. One strategy is to address injury‐induced demyelination of spared axons by promoting endogenous or exogenous remyelination. However, previously, we showed that new myelin was not necessary to regain hindlimb stepping following moderate thoracic spinal cord contusion in 3‐month‐old mice. The present analysis investigated two potential mechanisms by which animals can re‐establish locomotion in the absence of remyelination: compensation through intact white matter and conduction through spared axons. We induced a severe contusion injury to reduce the spared white matter rim in the remyelination deficient model, with no differences in recovery between remyelination deficient animals and injured littermate controls. We investigated the nodal properties of the axons at the lesion and found that in the remyelination deficient model, axons express the Nav1.2 voltage‐gated sodium channel, a sub‐type not typically expressed at mature nodes of Ranvier. In a moderate contusion injury, conduction velocities through the lesions of remyelination deficient animals were similar to those in animals with the capacity to remyelinate after injury. Detailed gait analysis and kinematics reveal subtle differences between remyelination deficient animals and remyelination competent controls, but no worse deficits. It is possible that upregulation of Nav1.2 channels may contribute to establishing conduction through the lesion. This conduction could contribute to compensation and regained motor function in mouse models of SCI. Such compensatory mechanism may have implications for interpreting efficacy results for remyelinating interventions in mice and the development of therapies for improving recovery following SCI. [ABSTRACT FROM AUTHOR]

Background: Glioblastoma (GBM) stands as the most prevalent and aggressive form of adult gliomas. Despite the implementation of intensive therapeutic approaches involving surgery, radiation, and chemotherapy, Glioblastoma Stem Cells contribute to tumor recurrence and poor prognosis. The induction of Glioblastoma Stem Cells differentiation by manipulating the transcriptional machinery has emerged as a promising strategy for GBM treatment. Here, we explored an innovative approach by investigating the role of the depolarized resting membrane potential (RMP) observed in patient-derived GBM sphereforming cell (GSCs), which allows them to maintain a stemness profile when they reside in the G0 phase of the cell cycle. Methods: We conducted molecular biology and electrophysiological experiments, both in vitro and in vivo, to examine the functional expression of the voltage-gated sodium channel (Nav) in GSCs, particularly focusing on its cell cycle-dependent functional expression. Nav activity was pharmacologically manipulated, and its effects on GSCs behavior were assessed by live imaging cell cycle analysis, self-renewal assays, and chemosensitivity assays. Mechanistic insights into the role of Nav in regulating GBM stemness were investigated through pathway analysis in vitro and through tumor proliferation assay in vivo. Results: We demonstrated that Nav is functionally expressed by GSCs mainly during the G0 phase of the cell cycle, suggesting its pivotal role in modulating the RMP. The pharmacological blockade of Nav made GBM cells more susceptible to temozolomide (TMZ), a standard drug for this type of tumor, by inducing cell cycle re-entry from G0 phase to G1/S transition. Additionally, inhibition of Nav substantially influenced the self-renewal and multipotency features of GSCs, concomitantly enhancing their degree of differentiation. Finally, our data suggested that Nav positively regulates GBM stemness by depolarizing the RMP and suppressing the ERK signaling pathway. Of note, in vivo proliferation assessment confirmed the increased susceptibility to TMZ following pharmacological blockade of Nav. Conclusions: This insight positions Nav as a promising prognostic biomarker and therapeutic target for GBM patients, particularly in conjunction with temozolomide treatment. [ABSTRACT FROM AUTHOR]

Tuberous Sclerosis Complex (TSC) is a lynchpin disorder, as it results in overactive mammalian target of rapamycin (mTOR) signaling, which has been implicated in a multitude of disease states. TSC is an autosomal dominant disease where 90% of affected individuals develop epilepsy. Epilepsy results from aberrant neuronal excitability that leads to recurring seizures. Under neurotypical conditions, the coordinated activity of voltage-gated ion channels keep neurons operating in an optimal range, thus providing network stability. Interestingly, loss or gain of function mutations in voltage-gated potassium, sodium, or calcium channels leads to altered excitability and seizures. To date, little is known about voltage-gated ion channel expression and function in TSC. However, data is beginning to emerge on how mTOR signaling regulates voltage-gated ion channel expression in neurons. Herein, we provide a comprehensive review of the literature describing common seizure types in patients with TSC, and suggest possible parallels between acquired epilepsies with known voltage-gated ion channel dysfunction. Furthermore, we discuss possible links towardmTOR regulation of voltage-gated ion channels expression and channel kinetics and the underlying epileptic manifestations in patients with TSC. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most common malignant primary brain cancer that, despite recent advances in the understanding of its pathogenesis, remains incurable. GBM contains a subpopulation of cells with stem cell-like properties called cancer stem cells (CSCs). Several studies have demonstrated that CSCs are resistant to conventional chemotherapy and radiation thus representing important targets for novel anti-cancer therapies. Proton sensing receptors expressed by CSCs could represent important factors involved in the adaptation of tumours to the extracellular environment. Accordingly, the expression of acid-sensing ion channels (ASICs), proton-gated sodium channels mainly expressed in the neurons of peripheral (PNS) and central nervous system (CNS), has been demonstrated in several tumours and linked to an increase in cell migration and proliferation. In this paper we report that the ASIC3 isoform, usually absent in the CNS and present in the PNS, is enriched in human GBM CSCs while poorly expressed in the healthy human brain. We propose here a novel therapeutic strategy based on the pharmacological activation of ASIC3, which induces a significant GBM CSCs damage while being non-toxic for neurons. This approach might offer a promising and appealing new translational pathway for the treatment of glioblastoma. [ABSTRACT FROM AUTHOR]

Antiseizure medications (ASMs) play a central role in seizure management, however, unpredictability in the response to treatment persists, even among patients with similar seizure manifestations and clinical backgrounds. An objective biomarker capable of reliably predicting the response to ASMs would profoundly impact epilepsy treatment. Presently, clinicians rely on a trial-and-error approach when selecting ASMs, a time-consuming process that can result in delays in receiving alternative non-pharmacological therapies such as a ketogenetic diet, epilepsy surgery, and neuromodulation therapies. Pharmacogenetic studies investigating the correlation between ASMs and genetic variants regarding their mechanistic targets offer promise in predicting the response to treatment. Sodium channel subunit genes have been extensively studied along with other ion channels and receptors as targets, however, the results have been conflicting, possibly due to methodological disparities including inconsistent definitions of drug response, variations in ASM combinations, and diversity of genetic variants/genes studied. Nonetheless, these studies underscore the potential effect of genetic variants on the mechanism of ASMs and consequently the prediction of treatment response. Recent advances in sequencing technology have led to the generation of large genetic datasets, which may be able to enhance the predictive accuracy of the response to ASMs. [ABSTRACT FROM AUTHOR]

Sand flies infect more than 1 million people annually with Leishmania parasites and other bacterial and viral pathogens. Progress in understanding sand fly adaptations to xenobiotics has been hampered by the limited availability of genomic resources. To address this gap, we sequenced, assembled, and annotated the transcriptomes of 11 phlebotomine sand fly species. Subsequently, we leveraged these genomic resources to generate novel evolutionary insights pertaining to their adaptations to xenobiotics, including those contributing to insecticide resistance. Specifically, we annotated over 2,700 sand fly detoxification genes and conducted large-scale phylogenetic comparisons to uncover the evolutionary dynamics of the five major detoxification gene families: cytochrome P450s (CYPs), glutathione-S-transferases (GSTs), UDP-glycosyltransferases (UGTs), carboxyl/cholinesterases (CCEs), and ATP-binding cassette (ABC) transporters. Using this comparative approach, we show that sand flies have evolved diverse CYP and GST gene repertoires, with notable lineage-specific expansions in gene groups evolutionarily related to known xenobiotic metabolizers. Furthermore, we show that sand flies have conserved orthologs of (i) CYP4G genes involved in cuticular hydrocarbon biosynthesis, (ii) ABCB genes involved in xenobiotic toxicity, and (iii) two primary insecticide targets, acetylcholinesterase-1 (Ace1) and voltage gated sodium channel (VGSC). The biological insights and genomic resources produced in this study provide a foundation for generating and testing hypotheses regarding the molecular mechanisms underlying sand fly adaptations to xenobiotics. [ABSTRACT FROM AUTHOR]

Background/Objectives: Epilepsy is a brain disease with both environmental and genetic inputs. Ion channel dysfunction seems to be of great significance for abnormal neuronal behavior during epileptic seizures. Within neurons, the voltage-gated sodium channels are crucial proteins contributing to the initiation and propagation of action potentials. The voltage-gated sodium channel α subunit 1 (SCN1A) gene encodes for the α subunit of a voltage-gated ion channel. The aim of the study was to investigate the relation of two common SCN1A variants, i.e., rs3812718 and rs2298771, with distinct epileptic phenotypes in a South-Eastern European population. Methods: DNA was extracted from 214 unrelated participants with focal onset, focal to bilateral tonic–clonic, or generalized onset epileptic seizures and genotyped using real-time PCR (LightSNiP assays) followed by melting curve analysis. Statistical analysis of the results was performed using IBM SPSS Statistics software (version 29.0 for Windows). Results: Genotype frequency distribution analysis indicated an association for the A-allele-containing genotypes of both rs3812718 and rs2298771 polymorphisms of SCN1A with generalized onset seizures and focal to bilateral tonic–clonic seizures versus focal onset seizures. Conclusions: Consequently, the study provides evidence that supports a potential association of the investigated SCN1A polymorphisms with distinct seizure subtype susceptibility in South-Eastern Europeans. [ABSTRACT FROM AUTHOR]

The effect of environmental change on activity of insecticides against insects has been greatly debated, and it is of significance to evaluate general patterns of change and explore the potential mechanisms that drive the changes in the context of global climate change. To that end, we constructed three multilevel meta-analyses and phylogenetically-corrected models based on 810 individual effect sizes of insecticide activity from 95 studies with variable levels of temperatures, humidities, and CO2 concentrations. We found that increasing temperatures could overall increase the insecticidal activity of insecticides by 1.33 times. Increasing temperatures will boost the activity of some types of insecticides (e.g., acetylcholinesterase inhibitors), but decrease the activity of some other types (e.g., sodium channel modulators). Activities of stomach toxicants and fumigants are overall more sensitive to increasing temperatures than other insecticides. The sensitivity of insects in Hemiptera, Coleoptera, and Diptera to insecticides will also tend to increase significantly due to increasing temperatures. The magnitude of warming was found to have strong interactive effects with both insecticide class and insect group. Although moisture changes were showed to have no significant effects on insecticidal activity overall, our meta-regression analyses identified a positive relationship between insecticide activity and the magnitude of humidity change. No significant relationships between changes in CO2 concentrations and insecticide activity were identified. Our results are critical in adaptation of insecticide application and pest management strategies, and forecasting insecticide risks (e.g., resistance development) across global climate regions under future warming conditions. [ABSTRACT FROM AUTHOR]

Introduction: Dravet Syndrome (DS) is a developmental and epileptic encephalopathy (EE) that typically begins in the first year of life. It's initial manifestation usually presents as a prolonged seizure (lasting more than five minutes) triggered by high fever. The incidence rate of Dravet Syndrome is estimated to be 1 in 15,700, with the majority of patients having a mutation in the SCN1A sodium channel gene. Objective: To elucidate the characteristics of Dravet Syndrome through the analysis of a clinical case. Materials and Methods: A child who was admitted repeatedly in the Neurology Department with complaints of complex febrile seizures (CFS) and status epilepticus (SE) exacerbated by fever was evaluated. The child underwent clinical-neurological, electroencephalographic (EEG), and molecular- genetic examinations. Results: The seizures occurred during fever, lasting more than 10 minutes and more than 30 minutes. The onset was at the age of 4 months, and by the age of 1 year, the child presented with CFS and SE with each fever. At the age of 1 year, the child also experienced other types of seizures- atonic, focal (left hand clonus, oral and ocular automatisms) in an afebrile context. Pathological signs included diffuse hypotonia. The initial EEG was within normal limits, but after 18 months, EEG anomalies during sleep appeared (focal activity in the left fronto-temporal cortical areas). Whole-exome sequencing revealed a mutation in the SCN1A gene. The diagnosis was Developmental and Epileptic Encephalopathy, Dravet Syndrome. The treatment plan included Valproic Acid, Clobazam, and Stiripentol. Conclusions: Dravet Syndrome is a severe EE, difficult to recognize at the onset. Early recognition and diagnosis of Dravet Syndrome contribute to the administration of targeted anticonvulsant medications, which can improve the child's long-term neurodevelopmental outcome [ABSTRACT FROM AUTHOR]

Vincristine-induced peripheral neuropathy is a common side effect of vincristine treatment, which is accompanied by pain and can be dose-limiting. The molecular mechanisms that underlie vincristine-induced pain are not well understood. We have established an animal model to investigate pathophysiological mechanisms of vincristine-induced pain. Our previous studies have shown that the tetrodotoxin-sensitive voltage-gated sodium channel Nav1.6 in medium-diameter dorsal root ganglion (DRG) neurons contributes to the maintenance of vincristine-induced allodynia. In this study, we investigated the effects of vincristine administration on excitability in small-diameter DRG neurons and whether the tetrodotoxin-resistant (TTX-R) Nav1.8 channels contribute to mechanical allodynia. Current-clamp recordings demonstrated that small DRG neurons become hyper-excitable following vincristine treatment, with both reduced current threshold and increased firing frequency. Using voltage-clamp recordings in small DRG neurons, we now show an increase in TTX-R current density and a −7.3 mV hyperpolarizing shift in the half-maximal potential (V1/2) of activation of Nav1.8 channels in vincristine-treated animals, which likely contributes to the hyperexcitability that we observed in these neurons. Notably, vincristine treatment did not enhance excitability of small DRG neurons from Nav1.8 knockout mice, and the development of mechanical allodynia was delayed but not abrogated in these mice. Together, our data suggest that sodium channel Nav1.8 in small DRG neurons contributes to the development of vincristine-induced mechanical allodynia. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Proposed Concept Antidepressants used by patients with bipolar disorder have been associated with destabilization with an increase in mania, depression, and cycling. The most commonly proposed mechanism, that antidepressants ‘overshoot’ their antidepressant effect to create a manic or mixed state, is unlikely since antidepressants have actually been found to be ineffective in treating bipolar depression. Beginning with known bipolar‐specific pathophysiologic abnormalities provides the greatest likelihood of insight.PubMed was queried with ‘bipolar’, ‘sodium’, ‘intracellular sodium’, ‘serotonin 3’, ‘5HT3’, ‘5‐hydroxytryptamine type 3 receptors’, and ‘antidepressant’ either individually or in combination.Pathologic mood states (both mania and depression) are associated with increased intracellular sodium (Na) concentrations that depolarize the resting membrane potential to increase cellular excitability (mania) or cause depolarization block (depression). Stimulation of the serotonin (5HT) receptors depolarizes the post‐synaptic neuron. Stimulation of 5HT3 may be of particular importance since it is coupled to a cation channel that directly depolarizes the membrane. These effects directly impact the physiology of patients with bipolar disorder to alter neuronal excitability in a fashion that worsens both mania and depression.The most consistently observed biological abnormality in individuals going through mania or bipolar depression involves a decline in Na pump activity, with consequent elevation of intracellular Na levels. Antidepressant treatment potentiates this, particularly by activation of 5HT3. This hypothesis can be tested by coadministering a 5HT3 antagonist (e.g., vortioxetine or ondansetron) to achieve blockade of that receptor while treating bipolar depression with a serotoninergic antidepressant. [ABSTRACT FROM AUTHOR]

Cardiac arrhythmia treatment is a clinical challenge necessitating safer and more effective therapies. Recent studies have highlighted the role of the perinexus, an intercalated disc nanodomain enriched in voltage-gated sodium channels including both Na v 1.5 and β1 subunits, adjacent to gap junctions. These findings offer insights into action potential conduction in the heart. A 19-amino acid SCN1B (β1/β1B) mimetic peptide, βadp1, disrupts VGSC beta subunit-mediated adhesion in cardiac perinexii, inducing arrhythmogenic changes. We aimed to explore βadp1's mechanism and develop novel SCN1B mimetic peptides affecting β1-mediated adhesion. Using patch clamp assays in neonatal rat cardiomyocytes and electric cell substrate impedance sensing (ECIS) in β1-expressing cells, we observed βadp1 maintained inhibitory effects for up to 5 h. A shorter peptide (LQLEED) based on the carboxyl-terminus of βadp1 mimicked this inhibitory effect, while dimeric peptides containing repeated LQLEED sequences paradoxically promoted intercellular adhesion over longer time courses. Moreover, we found a link between these peptides and β1-regulated intramembrane proteolysis (RIP) - a signaling pathway effecting gene transcription including that of VGSC subunits. βadp1 increased RIP continuously over 48 h, while dimeric agonists acutely boosted RIP for up to 6 h. In the presence of DAPT, an RIP inhibitor, βadp1's effects on ECIS-measured intercellular adhesion was reduced, suggesting a relationship between RIP and the peptide's inhibitory action. In conclusion, novel SCN1B (β1/β1B) mimetic peptides are reported with the potential to modulate intercellular VGSC β1-mediated adhesion, potentially through β1 RIP. These findings suggest a path towards the development of anti-arrhythmic drugs targeting the perinexus. [Display omitted] • Voltage-gated sodium channel β1 subunit offers novel anti-arrhythmic target. • β1 mimetic peptides increase regulated intramembrane proteolysis (RIP) of β1. • β1 mimetic peptide monomers decrease β1-mediated adhesion. • β1 mimetic peptide dimers stabilize or increase β1-mediated adhesion. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a highly prevalent joint disease that causes substantial disability, yet effective approaches to disease prevention or to the delay of OA progression are lacking. Emerging evidence has pinpointed ion channels as pivotal mediators in OA pathogenesis and as promising targets for disease-modifying treatments. Preclinical studies have assessed the potential of a variety of ion channel modulators to modify disease pathways involved in cartilage degeneration, synovial inflammation, bone hyperplasia and pain, and to provide symptomatic relief in models of OA. Some of these modulators are currently being evaluated in clinical trials. This review explores the structures and functions of ion channels, including transient receptor potential channels, Piezo channels, voltage-gated sodium channels, voltage-dependent calcium channels, potassium channels, acid-sensing ion channels, chloride channels and the ATP-dependent P2XR channels in the osteoarthritic joint. The discussion spans channel-targeting drug discovery and potential clinical applications, emphasizing opportunities for further research, and underscoring the growing clinical impact of ion channel biology in OA. Ion channels have key functions in chondrocytes, bone cells, immune cells and neurons. Liu and colleagues discuss how these functions might contribute to cartilage degeneration, bone formation inflammation and pain in osteoarthritis, and highlight the therapeutic potential of ion channel modulators. Key points: Ion channels have key functions in the joints and emerge as important contributors to pathogenic processes in osteoarthritis (OA). Dysregulation of mechanical and biochemical stimuli activates ion channels such as TRPV4 and Piezo channels, leading to Ca2+ and Na+ influx, which contributes to cartilage destruction, inflammation and pain in OA. Some ion channels typically associated with peripheral neurons are also expressed in chondrocytes and immune cells, and have a crucial role in the pathophysiology of OA. Exploration of ion channel expression, interactions, and properties in joints, along with development of specific channel agonists and antagonists, has helped to accelerate research on their potential roles in OA. Several ion channel modulators have been recently tested in animal models and patients with OA, with encouraging results. Targeting of ion channels holds promise for the development of new and more effective OA treatment strategies. [ABSTRACT FROM AUTHOR]

Epithelial Na+ channels (ENaCs) are activated by proteolysis of the α and γ subunits at specific sites flanking embedded inhibitory tracts. To examine the role of α subunit proteolysis in channel activation in vivo, we generated mice lacking the distal furin cleavage site in the α subunit (αF2M mice). On a normal Na+ control diet, no differences in ENaC protein abundance in kidney or distal colon were noted between wild‐type (WT) and αF2M mice. Patch‐clamp analyses revealed similar levels of ENaC activity in kidney tubules, while no physiologically relevant differences in blood chemistry or aldosterone levels were detected. Male αF2M mice did exhibit diminished ENaC activity in the distal colon, as measured by amiloride‐sensitive short‐circuit current (ISC). Following dietary Na+ restriction, WT and αF2M mice had similar natriuretic and colonic ISC responses to amiloride. However, single‐channel activity was significantly lower in kidney tubules from Na+‐restricted αF2M mice compared with WT littermates. ENaC α and γ subunit expression in kidney and distal colon were also enhanced in Na+‐restricted αF2Mvs. WT mice, in association with higher aldosterone levels. These data provide evidence that disrupting α subunit proteolysis impairs ENaC activity in vivo, requiring compensation in response to Na+ restriction. Key points: The epithelial Na+ channel (ENaC) is activated by proteolytic cleavage in vitro, but key questions regarding the role of ENaC proteolysis in terms of whole‐animal physiology remain to be addressed.We studied the in vivo importance of this mechanism by generating a mouse model with a genetic disruption to a key cleavage site in the ENaC's α subunit (αF2M mice).We found that αF2M mice did not exhibit a physiologically relevant phenotype under normal dietary conditions, but have impaired ENaC activation (channel open probability) in the kidney during salt restriction.ENaC function at the organ level was preserved in salt‐restricted αF2M mice, but this was associated with higher aldosterone levels and increased expression of ENaC subunits, suggesting compensation was required to maintain homeostasis.These results provide the first evidence that ENaC α subunit proteolysis is a key regulator of channel activity in vivo. [ABSTRACT FROM AUTHOR]

Since their discovery nearly 30 years ago, fibroblast growth factor homologous factors (FHFs) are now known to control the functionality of excitable tissues through a range of mechanisms. Nervous and cardiac system dysfunctions are caused by loss‐ or gain‐of‐function mutations in FHF genes. The best understood 'canonical' targets for FHF action are voltage‐gated sodium channels, and recent studies have expanded the repertoire of ways that FHFs modulate sodium channel gating. Additional 'non‐canonical' functions of FHFs in excitable and non‐excitable cells, including cancer cells, have been reported over the past dozen years. This review summarizes and evaluates reported canonical and non‐canonical FHF functions. [ABSTRACT FROM AUTHOR]

Tetrodotoxin (TTX) is a potent neurotoxin firstly discovered in the ovary of pufferfish. The genetic basis of voltage-gated sodium channel resistance to TTX has been widely studied, but it remains unclear in the evolution history of voltage-gated sodium channel resistance to TTX in pufferfish with different TTX concentrations. In this study, six scn4aa coding sequences of pufferfish were firstly cloned and sequenced, then used to investigate the adaptive evolution of scn4aa associated with TTX concentration and reconstruct ancestral sequences with seven scn4aa of other fishes. The result of CODEML (codon substitution model) program from the PAML (phylogenetic analysis by maximum likelihood) package shows only in the genus of Takifugu, which contains TTX highly in the liver, under positive selection. The result also indicates that three of four positively selected sites are located in the intracellular regions, which may compensate for normal function. The ancestral sequence reconstruction may suggest that the replacements providing weak toxin resistance might have appeared first in scn4aa, then the genus Takifugu evolved stronger resistance to TTX later. These results contribute to the explanation of the evolutional history of voltage-gated sodium channel resistance to TTX in pufferfish. [ABSTRACT FROM AUTHOR]

Background and Purpose: The voltage‐gated sodium channel isoform NaV1.7 is a high‐interest target for the development of non‐opioid analgesics due to its preferential expression in pain‐sensing neurons. NaV1.7 is also expressed in autonomic neurons, yet its contribution to involuntary visceral reflexes has received limited attention. The small molecule inhibitor ST‐2560 was advanced into pain behaviour and cardiovascular models to understand the pharmacodynamic effects of selective inhibition of NaV1.7. Experimental Approach: Potency of ST‐2560 at NaV1.7 and off‐target ion channels was evaluated by whole‐cell patch‐clamp electrophysiology. Effects on nocifensive reflexes were assessed in non‐human primate (NHP) behavioural models, employing the chemical capsaicin and mechanical stimuli. Cardiovascular parameters were monitored continuously in freely‐moving, telemetered NHPs following administration of vehicle and ST‐2560. Key Results: ST‐2560 is a potent inhibitor (IC50 = 39 nM) of NaV1.7 in primates with ≥1000‐fold selectivity over other isoforms of the human NaV1.x family. Following systemic administration, ST‐2560 (0.1–0.3 mg·kg−1, s.c.) suppressed noxious mechanical‐ and chemical‐evoked reflexes at free plasma concentrations threefold to fivefold above NaV1.7 IC50. ST‐2560 (0.1–1.0 mg·kg−1, s.c.) also produced changes in haemodynamic parameters, most notably a 10‐ to 20‐mmHg reduction in systolic and diastolic arterial blood pressure, at similar exposures. Conclusions and Implications: Acute pharmacological inhibition of NaV1.7 is antinociceptive, but also has the potential to impact the cardiovascular system. Further work is merited to understand the role of NaV1.7 in autonomic ganglia involved in the control of heart rate and blood pressure, and the effect of selective NaV1.7 inhibition on cardiovascular function. [ABSTRACT FROM AUTHOR]

BACKGROUND: Aphis gossypii is a worldwide agricultural pest that causes high levels of economic losses by feeding and transmitting virus diseases. It is usually controlled by chemical insecticides, but this could lead to the selection of resistant populations. Several single nucleotide polymorphisms (SNPs) have been identified associated with insecticide resistance. Monitoring activities to detect the presence of such mutations in field populations can have an important role in insect pest management but, currently, no information on Italian strains is available. RESULTS: The presence of target site mutations conferring resistance to different insecticides was analysed in Italian field collected populations of A. gossypii with an allele specific approach (QSGG, Qualitative Sybr‐Green Genotyping). Primers were designed to detect mutations in genes coding acetylcholinesterase (S431F), nicotinic acetylcholine receptor (R81T) and voltage‐gated sodium channel (M918L and L1014F). S431F was widespread but with high variability across populations. R81T was detected for the first time in Italy but only in two populations. The L1014F mutation (kdr) was not found, while in the samples showing the M918L two different nucleotidic substitutions were detected. Mutant allele frequencies were, respectively, 0.70 (S431), 0.31 (M918) and 0.02 (R81). Further analysis on the voltage‐gated sodium channel gene showed the presence of eight haplotypes and one non‐synonymous mutation in the gene coding region. CONCLUSION: Multiple target‐site mutations were detected within Italian populations. The combinations of genotypes observed in certain locations could affect negatively the control of this pest. Preliminary insights on the genetic structure in the Italian populations of A. gossypii were acquired. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Artificial ion channels that enable high-efficiency ion transport have important implications in nanofluidics and biomedical applications such as drug delivery. Herein, we show a simulation-based chemical design of a biomimetic sodium channel that possesses permeation rate and selectivity potentially higher than those of the state-of-the-art natural vertebrate voltage-gated sodium channels. Importantly, our theoretical findings have undergone empirical testing, aligning well with the Arrhenius law as derived from a diverse range of experimental results. The high-efficiency ion transport is achieved by anchoring the carboxylate functional groups within the channel filter. A key chemical guiding principle underlying the ion channel design is that the freeenergy barrier for the Na+ passage across the channel should be comparable to typical thermal energy at room temperature. With the implementation of the chemical design, we found that the relatively low free-energy barrier can be attributed to the compensation effect of the carboxylate groups to the partially lost oxygen shell of the ion within the ion channel, as well as to the consonant vibration of the ions inside and outside the channel. This mechanistic understanding brings new insight, at the molecular level, into the high-efficiency ion transport across the designed membrane channels. The proof of principle achieved from the simulations will stimulate future experimental confirmation and potential applications of the high-performance artificial channels in nanofluidics and in bioinspired iontronics. [ABSTRACT FROM AUTHOR]

Resistance to insecticides is one of the great challenges that vector control programs must face. The constant use of pyrethroid-type insecticides worldwide has caused selection pressure in populations of the Aedes aegypti vector, which has promoted the emergence of resistant populations. The resistance mechanism to pyrethroid insecticides most studied to date is target-site mutations that desensitize the voltage-gated sodium channel (VGSC) of the insect to the action of pyrethroids. In the present study, susceptibility to the pyrethroid insecticides permethrin, lambda-cyhalothrin, and deltamethrin was evaluated in fourteen populations from the department of Córdoba, Colombia. The CDC bottle bioassay and WHO tube methods were used. Additionally, the frequencies of the F1534C, V1016I, and V410L mutations were determined, and the association of resistance with the tri-locus haplotypes was examined. The results varied between the two techniques used, with resistance to permethrin observed in thirteen of the fourteen populations, resistance to lambda-cyhalothrin in two populations, and susceptibility to deltamethrin in all the populations under study with the CDC method. In contrast, the WHO method showed resistance to the three insecticides evaluated in all populations. The frequencies of the mutated alleles ranged from 0.05–0.43 for 1016I, 0.94–1.0 for 1534C, and 0.01–0.59 for 410L. The triple homozygous mutant CIL haplotype was associated with resistance to all three pyrethroids evaluated with the WHO bioassay, while with the CDC bioassay, it was only associated with resistance to permethrin. This study highlights the importance of implementing systematic monitoring of kdr mutations, allowing resistance management strategies to be dynamically adjusted to achieve effective control of Aedes aegypti. [ABSTRACT FROM AUTHOR]