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1.
Cell Chem Biol ; 31(7): 1233-1235, 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39029451

RESUMEN

In this issue of Cell Chemical Biology, Elleman et al.1 introduce a transformative chemical approach to control neuronal activity with high spatial and temporal resolution. The authors present STX-bpc, a potent neurotoxin that naturally inhibits voltage-gated sodium channels (NaVs), complementing available optogenetic methods for manipulating neuronal activity, cellular communication, and behavior.


Asunto(s)
Neuronas , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/citología , Animales , Humanos , Optogenética , Canales de Sodio Activados por Voltaje/metabolismo , Canales de Sodio Activados por Voltaje/química , Neurotoxinas/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química
2.
Bioorg Chem ; 150: 107605, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38971095

RESUMEN

The dorsal root ganglion (DRG) is the primary neuron responsible for transmitting peripheral pain signals to the central nervous system and plays a crucial role in pain transduction. Modulation of DRG excitability is considered a viable approach for pain management. Neuronal excitability is intricately linked to the ion channels on the neurons. The small and medium-sized DRG neurons are chiefly engaged in pain conduction and have high levels of TTX-S sodium channels, with Nav1.7 accounting for approximately 80% of the current. Voltage-gated sodium channel (VGSC or Nav) blockers are vital targets for the management of central nervous system diseases, particularly chronic pain. VGSCs play a key role in controlling cellular excitability. Clinical research has shown that Nav1.7 plays a crucial role in pain sensation, and there is strong genetic evidence linking Nav1.7 and its encoding gene SCN9A gene to painful disorders in humans. Many studies have shown that Nav1.7 plays an important role in pain management. The role of Nav1.7 in pain signaling pathways makes it an attractive target for the potential development of new pain drugs. Meanwhile, understanding the architecture of Nav1.7 may help to develop the next generation of painkillers. This review provides updates on the recently reported molecular inhibitors targeting the Nav1.7 pathway, summarizes their structure-activity relationships (SARs), and discusses their therapeutic effects on painful diseases. Pharmaceutical chemists are working to improve the therapeutic index of Nav1.7 inhibitors, achieve better analgesic effects, and reduce side effects. We hope that this review will contribute to the development of novel Nav1.7 inhibitors as potential drugs.


Asunto(s)
Canal de Sodio Activado por Voltaje NAV1.7 , Bloqueadores del Canal de Sodio Activado por Voltaje , Humanos , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/uso terapéutico , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Dolor en Cáncer/tratamiento farmacológico , Dolor en Cáncer/metabolismo , Analgésicos/química , Analgésicos/farmacología , Analgésicos/uso terapéutico , Animales , Relación Estructura-Actividad , Manejo del Dolor/métodos , Estructura Molecular , Neoplasias/tratamiento farmacológico , Bloqueadores de los Canales de Sodio/farmacología , Bloqueadores de los Canales de Sodio/química , Bloqueadores de los Canales de Sodio/uso terapéutico
3.
J Biol Chem ; 300(1): 105577, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38110035

RESUMEN

Harvester ants (genus Pogonomyrmex) are renowned for their stings which cause intense, long-lasting pain, and other neurotoxic symptoms in vertebrates. Here, we show that harvester ant venoms are relatively simple and composed largely of peptide toxins. One class of peptides is primarily responsible for the long-lasting local pain of envenomation via activation of peripheral sensory neurons. These hydrophobic, cysteine-free peptides potently modulate mammalian voltage-gated sodium (NaV) channels, reducing the voltage threshold for activation and inhibiting channel inactivation. These toxins appear to have evolved specifically to deter vertebrates.


Asunto(s)
Hormigas , Mordeduras y Picaduras , Dolor , Péptidos , Toxinas Biológicas , Bloqueadores del Canal de Sodio Activado por Voltaje , Canales de Sodio Activados por Voltaje , Animales , Hormigas/patogenicidad , Hormigas/fisiología , Mordeduras y Picaduras/complicaciones , Dolor/inducido químicamente , Dolor/complicaciones , Péptidos/química , Péptidos/farmacología , Péptidos/toxicidad , Células Receptoras Sensoriales/efectos de los fármacos , Células Receptoras Sensoriales/fisiología , Toxinas Biológicas/química , Toxinas Biológicas/farmacología , Toxinas Biológicas/toxicidad , Vertebrados , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/toxicidad , Canales de Sodio Activados por Voltaje/metabolismo
4.
Nat Commun ; 14(1): 3224, 2023 06 03.
Artículo en Inglés | MEDLINE | ID: mdl-37270609

RESUMEN

Voltage-gated sodium (Nav) channels are targeted by a number of widely used and investigational drugs for the treatment of epilepsy, arrhythmia, pain, and other disorders. Despite recent advances in structural elucidation of Nav channels, the binding mode of most Nav-targeting drugs remains unknown. Here we report high-resolution cryo-EM structures of human Nav1.7 treated with drugs and lead compounds with representative chemical backbones at resolutions of 2.6-3.2 Å. A binding site beneath the intracellular gate (site BIG) accommodates carbamazepine, bupivacaine, and lacosamide. Unexpectedly, a second molecule of lacosamide plugs into the selectivity filter from the central cavity. Fenestrations are popular sites for various state-dependent drugs. We show that vinpocetine, a synthetic derivative of a vinca alkaloid, and hardwickiic acid, a natural product with antinociceptive effect, bind to the III-IV fenestration, while vixotrigine, an analgesic candidate, penetrates the IV-I fenestration of the pore domain. Our results permit building a 3D structural map for known drug-binding sites on Nav channels summarized from the present and previous structures.


Asunto(s)
Carbamazepina , Bloqueadores del Canal de Sodio Activado por Voltaje , Humanos , Analgésicos/farmacología , Lacosamida , Dolor , Dominios Proteicos , Canales de Sodio Activados por Voltaje/metabolismo , Bloqueadores del Canal de Sodio Activado por Voltaje/química
5.
Molecules ; 28(10)2023 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-37241973

RESUMEN

Diterpenoid alkaloids, originating from the amination of natural tetracyclic diterpenes, have long interested scientists due to their medicinal uses and infamous toxicity which has limited the clinical application of the native compound. Alkaloid lappaconitine extracted from various Aconitum and Delphinium species has displayed extensive bioactivities and active ongoing research to reduce its adverse effects. A convenient route to construct hybrid molecules containing diterpenoid alkaloid lappaconitine and 3H-1,5-benzodiazepine fragments was proposed. The key stage involved the formation of 5'-alkynone-lappaconitines in situ by acyl Sonogashira coupling of 5'-ethynyllappaconitine, followed by cyclocondensation with o-phenylenediamine. New hybrid compounds showed low toxicity and outstanding analgesic activity in experimental pain models, which depended on the nature of the substituent in the benzodiazepine nucleus. An analogous dependence was also shown for the antiarrhythmic activity in the epinephrine arrhythmia test in vivo. Studies on the isolated atrium have shown that the mechanism of action of the new compounds is included the blockade of beta-adrenergic receptors and potassium channels. Molecular docking analysis was conducted to determine the binding potential of target molecules with the voltage-gated sodium channel NaV1.5. All obtained results provide a basis for future rational modifications of lappaconitine, reducing side effects, while retaining its therapeutic effects.


Asunto(s)
Aconitina , Analgésicos no Narcóticos , Antiarrítmicos , Benzodiazepinas , Bloqueadores del Canal de Sodio Activado por Voltaje , Aconitina/análogos & derivados , Aconitina/síntesis química , Aconitina/farmacología , Benzodiazepinas/síntesis química , Benzodiazepinas/química , Benzodiazepinas/farmacología , Modelos Moleculares , Analgésicos no Narcóticos/síntesis química , Analgésicos no Narcóticos/química , Analgésicos no Narcóticos/farmacología , Unión Proteica , Animales , Ratas , Ratas Wistar , Antiarrítmicos/síntesis química , Antiarrítmicos/química , Antiarrítmicos/farmacología , Canal de Sodio Activado por Voltaje NAV1.5 , Masculino , Ratones , Ratones Endogámicos , Bloqueadores del Canal de Sodio Activado por Voltaje/síntesis química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Simulación del Acoplamiento Molecular
6.
FEBS J ; 290(14): 3688-3702, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36912793

RESUMEN

Venom-derived peptides targeting ion channels involved in pain are regarded as a promising alternative to current, and often ineffective, chronic pain treatments. Many peptide toxins are known to specifically and potently block established therapeutic targets, among which the voltage-gated sodium and calcium channels are major contributors. Here, we report on the discovery and characterization of a novel spider toxin isolated from the crude venom of Pterinochilus murinus that shows inhibitory activity at both hNaV 1.7 and hCaV 3.2 channels, two therapeutic targets implicated in pain pathways. Bioassay-guided HPLC fractionation revealed a 36-amino acid peptide with three disulfide bridges named µ/ω-theraphotoxin-Pmu1a (Pmu1a). Following isolation and characterization, the toxin was chemically synthesized and its biological activity was further assessed using electrophysiology, revealing Pmu1a to be a toxin that potently blocks both hNaV 1.7 and hCaV 3. Nuclear magnetic resonance structure determination of Pmu1a shows an inhibitor cystine knot fold that is the characteristic of many spider peptides. Combined, these data show the potential of Pmu1a as a basis for the design of compounds with dual activity at the therapeutically relevant hCaV 3.2 and hNaV 1.7 voltage-gated channels.


Asunto(s)
Venenos de Araña , Arañas , Animales , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Venenos de Araña/farmacología , Venenos de Araña/química , Venenos de Araña/metabolismo , Dolor , Péptidos/farmacología , Espectroscopía de Resonancia Magnética , Arañas/metabolismo
7.
J Biol Chem ; 299(4): 103068, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36842500

RESUMEN

µ-Conotoxin KIIIA, a selective blocker of sodium channels, has strong inhibitory activity against several Nav isoforms, including Nav1.7, and has potent analgesic effects, but it contains three pairs of disulfide bonds, making structural modification difficult and synthesis complex. To circumvent these difficulties, we designed and synthesized three KIIIA analogues with one disulfide bond deleted. The most active analogue, KIIIA-1, was further analyzed, and its binding pattern to hNav1.7 was determined by molecular dynamics simulations. Guided by the molecular dynamics computational model, we designed and tested 32 second-generation and 6 third-generation analogues of KIIIA-1 on hNav1.7 expressed in HEK293 cells. Several analogues showed significantly improved inhibitory activity on hNav1.7, and the most potent peptide, 37, was approximately 4-fold more potent than the KIIIA Isomer I and 8-fold more potent than the wildtype (WT) KIIIA in inhibiting hNav1.7 current. Intraperitoneally injected 37 exhibited potent in vivo analgesic activity in a formalin-induced inflammatory pain model, with activity reaching ∼350-fold of the positive control drug morphine. Overall, peptide 37 has a simplified disulfide-bond framework and exhibits potent in vivo analgesic effects and has promising potential for development as a pain therapy in the future.


Asunto(s)
Analgésicos , Conotoxinas , Canal de Sodio Activado por Voltaje NAV1.7 , Bloqueadores del Canal de Sodio Activado por Voltaje , Humanos , Analgésicos/farmacología , Analgésicos/química , Conotoxinas/química , Conotoxinas/farmacología , Disulfuros/metabolismo , Células HEK293 , Simulación de Dinámica Molecular , Dolor/inducido químicamente , Dolor/tratamiento farmacológico , Péptidos/farmacología , Péptidos/metabolismo , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología
8.
Elife ; 112022 12 28.
Artículo en Inglés | MEDLINE | ID: mdl-36576241

RESUMEN

The voltage-gated sodium NaV1.7 channel plays a key role as a mediator of action potential propagation in C-fiber nociceptors and is an established molecular target for pain therapy. ProTx-II is a potent and moderately selective peptide toxin from tarantula venom that inhibits human NaV1.7 activation. Here we used available structural and experimental data to guide Rosetta design of potent and selective ProTx-II-based peptide inhibitors of human NaV1.7 channels. Functional testing of designed peptides using electrophysiology identified the PTx2-3127 and PTx2-3258 peptides with IC50s of 7 nM and 4 nM for hNaV1.7 and more than 1000-fold selectivity over human NaV1.1, NaV1.3, NaV1.4, NaV1.5, NaV1.8, and NaV1.9 channels. PTx2-3127 inhibits NaV1.7 currents in mouse and human sensory neurons and shows efficacy in rat models of chronic and thermal pain when administered intrathecally. Rationally designed peptide inhibitors of human NaV1.7 channels have transformative potential to define a new class of biologics to treat pain.


Asunto(s)
Canal de Sodio Activado por Voltaje NAV1.7 , Dolor , Péptidos , Bloqueadores del Canal de Sodio Activado por Voltaje , Animales , Humanos , Ratones , Ratas , Nociceptores , Dolor/tratamiento farmacológico , Péptidos/farmacología , Péptidos/química , Venenos de Araña/química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Diseño de Fármacos
9.
Zool Res ; 43(5): 886-896, 2022 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-36052553

RESUMEN

Various peptide toxins in animal venom inhibit voltage-gated sodium ion channel Nav1.7, including Nav-targeting spider toxin (NaSpTx) Family I. Toxins in NaSpTx Family I share a similar structure, i.e., N-terminal, loops 1-4, and C-terminal. Here, we used Mu-theraphotoxin-Ca2a (Ca2a), a peptide isolated from Cyriopagopus albostriatus, as a template to investigate the general properties of toxins in NaSpTx Family I. The toxins interacted with the cell membrane prior to binding to Nav1.7 via similar hydrophobic residues. Residues in loop 1, loop 4, and the C-terminal primarily interacted with the S3-S4 linker of domain II, especially basic amino acids binding to E818. We also identified the critical role of loop 2 in Ca2a regarding its affinity to Nav1.7. Our results provide further evidence that NaSpTx Family I toxins share similar structures and mechanisms of binding to Nav1.7.


Asunto(s)
Venenos de Araña , Animales , Péptidos/química , Canales de Sodio , Venenos de Araña/química , Venenos de Araña/genética , Venenos de Araña/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/uso terapéutico
10.
Toxins (Basel) ; 14(9)2022 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-36136538

RESUMEN

µ-Conotoxins are small, potent, peptide voltage-gated sodium (NaV) channel inhibitors characterised by a conserved cysteine framework. Despite promising in vivo studies indicating analgesic potential of these compounds, selectivity towards the therapeutically relevant subtype NaV1.7 has so far been limited. We recently identified a novel µ-conotoxin, SxIIIC, which potently inhibits human NaV1.7 (hNaV1.7). SxIIIC has high sequence homology with other µ-conotoxins, including SmIIIA and KIIIA, yet shows different NaV channel selectivity for mammalian subtypes. Here, we evaluated and compared the inhibitory potency of µ-conotoxins SxIIIC, SmIIIA and KIIIA at hNaV channels by whole-cell patch-clamp electrophysiology and discovered that these three closely related µ-conotoxins display unique selectivity profiles with significant variations in inhibitory potency at hNaV1.7. Analysis of other µ-conotoxins at hNaV1.7 shows that only a limited number are capable of inhibition at this subtype and that differences between the number of residues in loop 3 appear to influence the ability of µ-conotoxins to inhibit hNaV1.7. Through mutagenesis studies, we confirmed that charged residues in this region also affect the selectivity for hNaV1.4. Comparison of µ-conotoxin NMR solution structures identified differences that may contribute to the variance in hNaV1.7 inhibition and validated the role of the loop 1 extension in SxIIIC for improving potency at hNaV1.7, when compared to KIIIA. This work could assist in designing µ-conotoxin derivatives specific for hNaV1.7.


Asunto(s)
Conotoxinas , Bloqueadores del Canal de Sodio Activado por Voltaje , Analgésicos/química , Analgésicos/farmacología , Animales , Conotoxinas/química , Conotoxinas/farmacología , Cisteína , Humanos , Canal de Sodio Activado por Voltaje NAV1.4 , Canal de Sodio Activado por Voltaje NAV1.7 , Péptidos , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología
11.
J Nat Prod ; 85(9): 2199-2206, 2022 09 23.
Artículo en Inglés | MEDLINE | ID: mdl-35994072

RESUMEN

Tetrodotoxin (TTX, 1) is a potent voltage-gated sodium channel blocker detected in certain marine and terrestrial organisms. We report here a new TTX analogue, 9-epiTTX (2), and a TTX-related compound, Tb-242B (4), isolated from the pufferfish Takifugu flavipterus and Dichotomyctere ocellatus, respectively. NMR analysis suggested that 2 exists as a mixture of hemilactal and 10,8-lactone forms, whereas other reported TTX analogues are commonly present as an equilibrium mixture of hemilactal and 10,7-lactone forms. Compound 2 and TTX were confirmed not to convert to each other by incubation under neutral and acidic conditions at 37 °C for 24 h. Compound 4 was identified as the 9-epimer of Tb-242A (3), previously reported as a possible biosynthetic precursor of TTX. Compound 4 was partially converted to 3 by incubation in a neutral buffer at 37 °C for 7 days, whereas 3 was not converted to 4 under this condition. Compound 2 was detected in several TTX-containing marine animals and a newt. Mice injected with 600 ng of 2 by intraperitoneal injection did not show any adverse symptoms, suggesting that the C-9 configuration in TTX is critical for its biological activity. Based on the structures, 2 and 4 were predicted to be shunt products for TTX biosynthesis.


Asunto(s)
Takifugu , Tetraodontiformes , Tetrodotoxina , Bloqueadores del Canal de Sodio Activado por Voltaje , Animales , Lactonas/química , Lactonas/aislamiento & purificación , Ratones , Tetrodotoxina/química , Tetrodotoxina/aislamiento & purificación , Tetrodotoxina/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/aislamiento & purificación , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología
12.
Proc Natl Acad Sci U S A ; 119(30): e2208211119, 2022 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-35858452

RESUMEN

The dorsal root ganglia-localized voltage-gated sodium (Nav) channel Nav1.8 represents a promising target for developing next-generation analgesics. A prominent characteristic of Nav1.8 is the requirement of more depolarized membrane potential for activation. Here we present the cryogenic electron microscopy structures of human Nav1.8 alone and bound to a selective pore blocker, A-803467, at overall resolutions of 2.7 to 3.2 Å. The first voltage-sensing domain (VSDI) displays three different conformations. Structure-guided mutagenesis identified the extracellular interface between VSDI and the pore domain (PD) to be a determinant for the high-voltage dependence of activation. A-803467 was clearly resolved in the central cavity of the PD, clenching S6IV. Our structure-guided functional characterizations show that two nonligand binding residues, Thr397 on S6I and Gly1406 on S6III, allosterically modulate the channel's sensitivity to A-803467. Comparison of available structures of human Nav channels suggests the extracellular loop region to be a potential site for developing subtype-specific pore-blocking biologics.


Asunto(s)
Compuestos de Anilina , Furanos , Canal de Sodio Activado por Voltaje NAV1.7 , Bloqueadores del Canal de Sodio Activado por Voltaje , Regulación Alostérica , Compuestos de Anilina/química , Compuestos de Anilina/farmacología , Microscopía por Crioelectrón , Furanos/química , Furanos/farmacología , Humanos , Potenciales de la Membrana , Canal de Sodio Activado por Voltaje NAV1.7/química , Dominios Proteicos , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología
13.
Bioorg Med Chem Lett ; 73: 128892, 2022 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-35850422

RESUMEN

NaV1.7 is an actively pursued, genetically validated, target for pain. Recently reported quinolinone sulfonamide inhibitors displayed promising selectivity profiles as well as efficacy in preclinical pain models; however, concerns about off-target liabilities associated with this series resulted in an effort to reduce the lipophilicity of these compounds. Successful prosecution of this strategy was challenging due to the opposing requirement for lipophilic inhibitors for NaV1.7 potency and in vivo clearance (CL). Deconstruction of the heterocyclic core of the quinolinone series and utilization of an intramolecular hydrogen bond to mimic the requisite pharmacophore enabled the introduction of polarity without adversely impacting CL. Ultimately, this strategy led to the identification of compound 29, which demonstrated favorable ADME and was efficacious in pre-clinical models of pain.


Asunto(s)
Canal de Sodio Activado por Voltaje NAV1.7 , Quinolonas , Humanos , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Dolor/tratamiento farmacológico , Relación Estructura-Actividad , Sulfanilamida , Sulfonamidas/química , Sulfonamidas/farmacología , Urea/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química
14.
Mar Drugs ; 20(2)2022 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-35200683

RESUMEN

The voltage-gated sodium channel subtype 1.2 (NaV1.2) is instrumental in the initiation of action potentials in the nervous system, making it a natural drug target for neurological diseases. Therefore, there is much pharmacological interest in finding blockers of NaV1.2 and improving their affinity and selectivity properties. An extensive family of peptide toxins from cone snails (conotoxins) block NaV channels, thus they provide natural templates for the design of drugs targeting NaV channels. Unfortunately, progress was hampered due to the absence of any NaV structures. The recent determination of cryo-EM structures for NaV channels has finally broken this impasse. Here, we use the NaV1.2 structure in complex with µ-conotoxin KIIIA (KIIIA) in computational studies with the aim of improving KIIIA's affinity and blocking capacity for NaV1.2. Only three KIIIA amino acid residues are available for mutation (S5, S6, and S13). After performing molecular modeling and simulations on NaV1.2-KIIIA complex, we have identified the S5R, S6D, and S13K mutations as the most promising for additional contacts. We estimate these contacts to boost the affinity of KIIIA for NaV1.2 from nanomole to picomole domain. Moreover, the KIIIA[S5R, S6D, S13K] analogue makes contacts with all four channel domains, thus enabling the complete blocking of the channel (KIIIA partially blocks as it has contacts with three domains). The proposed KIIIA analogue, once confirmed experimentally, may lead to novel anti-epileptic drugs.


Asunto(s)
Conotoxinas/farmacología , Canal de Sodio Activado por Voltaje NAV1.2/efectos de los fármacos , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Secuencia de Aminoácidos , Animales , Anticonvulsivantes/química , Anticonvulsivantes/farmacología , Conotoxinas/química , Caracol Conus , Diseño de Fármacos , Humanos , Modelos Moleculares , Simulación de Dinámica Molecular , Mutación , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/aislamiento & purificación
15.
J Biol Chem ; 298(3): 101728, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35167877

RESUMEN

µ-Conotoxins are components of cone snail venom, well-known for their analgesic activity through potent inhibition of voltage-gated sodium channel (NaV) subtypes, including NaV1.7. These small, disulfide-rich peptides are typically stabilized by three disulfide bonds arranged in a 'native' CysI-CysIV, CysII-CysV, CysIII-CysVI pattern of disulfide connectivity. However, µ-conotoxin KIIIA, the smallest and most studied µ-conotoxin with inhibitory activity at NaV1.7, forms two distinct disulfide bond isomers during thermodynamic oxidative folding, including Isomer 1 (CysI-CysV, CysII-CysIV, CysIII-CysVI) and Isomer 2 (CysI-CysVI, CysII-CysIV, CysIII-CysV), but not the native µ-conotoxin arrangement. To date, there has been no study on the structure and activity of KIIIA comprising the native µ-conotoxin disulfide bond arrangement. Here, we evaluated the synthesis, potency, sodium channel subtype selectivity, and 3D structure of the three isomers of KIIIA. Using a regioselective disulfide bond-forming strategy, we synthetically produced the three µ-conotoxin KIIIA isomers displaying distinct bioactivity and NaV subtype selectivity across human NaV channel subtypes 1.2, 1.4, and 1.7. We show that Isomer 1 inhibits NaV subtypes with a rank order of potency of NaV1.4 > 1.2 > 1.7 and Isomer 2 in the order of NaV1.4≈1.2 > 1.7, while the native isomer inhibited NaV1.4 > 1.7≈1.2. The three KIIIA isomers were further evaluated by NMR solution structure analysis and molecular docking with hNaV1.2. Our study highlights the importance of investigating alternate disulfide isomers, as disulfide connectivity affects not only the overall structure of the peptides but also the potency and subtype selectivity of µ-conotoxins targeting therapeutically relevant NaV subtypes.


Asunto(s)
Conotoxinas , Bloqueadores del Canal de Sodio Activado por Voltaje , Canales de Sodio Activados por Voltaje , Conotoxinas/química , Conotoxinas/farmacología , Disulfuros/química , Disulfuros/farmacología , Humanos , Simulación del Acoplamiento Molecular , Relación Estructura-Actividad , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Canales de Sodio Activados por Voltaje/química , Canales de Sodio Activados por Voltaje/metabolismo
16.
Br J Pharmacol ; 179(3): 473-486, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34411279

RESUMEN

BACKGROUND AND PURPOSE: Voltage-gated sodium (NaV ) channels are expressed de novo in carcinomas where their activity promotes invasiveness. Breast and colon cancer cells express the neonatal splice variant of NaV 1.5 (nNaV 1.5), which has several amino acid substitutions in the domain I voltage-sensor compared with its adult counterpart (aNaV 1.5). This study aimed to determine whether nNaV 1.5 channels could be distinguished pharmacologically from aNaV 1.5 channels. EXPERIMENTAL APPROACH: Cells expressing either nNaV 1.5 or aNaV 1.5 channels were exposed to low MW inhibitors, an antibody or natural toxins, and changes in electrophysiological parameters were measured. Stable expression in EBNA cells and transient expression in Xenopus laevis oocytes were used. Currents were recorded by whole-cell patch clamp and two-electrode voltage-clamp, respectively. KEY RESULTS: Several clinically used blockers of NaV channels (lidocaine, procaine, phenytoin, mexiletine, ranolazine, and riluzole) could not distinguish between nNaV 1.5 or aNaV 1.5 channels. However, two tarantula toxins (HaTx and ProTx-II) and a polyclonal antibody (NESOpAb) preferentially inhibited currents elicited by either nNaV 1.5 or aNaV 1.5 channels by binding to the spliced region of the channel. Furthermore, the amino acid residue at position 211 (aspartate in aNaV 1.5/lysine in nNaV 1.5), that is, the charge reversal in the spliced region of the channel, played a key role in the selectivity, especially in antibody binding. CONCLUSION AND IMPLICATIONS: We conclude that the cancer-related nNaV 1.5 channel can be distinguished pharmacologically from its nearest neighbour, aNaV 1.5 channels. Thus, it may be possible to design low MW compounds as antimetastatic drugs for non-toxic therapy of nNaV 1.5-expressing carcinomas.


Asunto(s)
Carcinoma , Venenos de Araña , Canales de Sodio Activados por Voltaje , Humanos , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Venenos de Araña/química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Canales de Sodio Activados por Voltaje/metabolismo
18.
Bioorg Chem ; 115: 105230, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34416507

RESUMEN

Voltage-gated sodium channel blockers are one of the vital targets for the management of several central nervous system diseases, including epilepsy, chronic pain, psychiatric disorders, and spasticity. The voltage-gated sodium channels play a key role in controlling cellular excitability. This reduction in excitotoxicity is also applied to improve the symptoms of epileptic conditions. The effectiveness of antiepileptic drugs as sodium channel depends upon the reversible blocking of the spontaneous discharge without blocking its propagation. There are number of antiepileptic drug(s) which are in pipeline to flour the market to conquer abnormal neuronal excitability. They inhibit the seizures through the inhibition of complex voltage- and frequency-dependent ionic currents through sodium channels. Over the past decade, the sodium channel is one of the most explored targets to control or treat the seizure, but there has not been any game-changing discovery yet. Although there are large numbers of drugs approved for the treatment of epilepsy, however they are associated with several acute to chronic side effects. Many research groups have tirelessly worked for better therapeutic medication on this popular target to treat epileptic seizures. The review quotes briefly the developments of the approved examples of sodium channel blockers as anticonvulsant drugs. Medicinal chemists have tried the design and development of some more potent anticonvulsant drugs to minimize the toxicity that are discussed here, and an emphasis is given for their possible mechanism and the structure-activity relationship (SAR).


Asunto(s)
Anticonvulsivantes/farmacología , Convulsiones/tratamiento farmacológico , Canales de Sodio/metabolismo , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Animales , Anticonvulsivantes/química , Relación Dosis-Respuesta a Droga , Desarrollo de Medicamentos , Humanos , Estructura Molecular , Convulsiones/metabolismo , Relación Estructura-Actividad , Bloqueadores del Canal de Sodio Activado por Voltaje/química
19.
Peptides ; 145: 170622, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34363923

RESUMEN

Peptides isolated from spider venoms are of pharmacological interest due to their neurotoxic activity, acting on voltage-dependent ion channels present in different types of human body tissues. Three peptide toxins titled as Ap2, Ap3 and Ap5 were purified by RP-HPLC from Acanthoscurria paulensis venom. They were partially sequenced by MALDI In-source Decay method and their sequences were completed and confirmed by transcriptome analysis of the venom gland. The Ap2, Ap3 and Ap5 peptides have, respectively, 42, 41 and 46 amino acid residues, and experimental molecular masses of 4886.3, 4883.7 and 5454.7 Da, with the Ap2 peptide presenting an amidated C-terminus. Amongst the assayed channels - NaV1.1, NaV1.5, NaV1.7, CaV1.2, CaV2.1 and CaV2.2 - Ap2, Ap3 and Ap5 inhibited 20-30 % of CaV2.1 current at 1 µM concentration. Ap3 also inhibited sodium current in NaV1.1, Nav1.5 and Nav1.7 channels by 6.6 ± 1.91 % (p = 0.0276), 4.2 ± 1.09 % (p = 0.0185) and 16.05 ± 2.75 % (p = 0.0282), respectively. Considering that Ap2, Ap3 and Ap5 belong to the 'U'-unknown family of spider toxins, which has few descriptions of biological activity, the present work contributes to the knowledge of these peptides and demonstrates this potential as channel modulators.


Asunto(s)
Agatoxinas/aislamiento & purificación , Agatoxinas/farmacología , Venenos de Araña/química , Agatoxinas/química , Animales , Células CHO , Canales de Calcio Tipo N/metabolismo , Cricetulus , Células HEK293 , Humanos , Péptidos/química , Péptidos/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Arañas , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Canales de Sodio Activados por Voltaje/genética , Canales de Sodio Activados por Voltaje/metabolismo
20.
J Ethnopharmacol ; 280: 114457, 2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34329712

RESUMEN

ETHNOPHARMACOLOGY RELEVANCE: Pain often causes a series of abnormal changes in physiology and psychology, which can lead to disease and even death. Drug therapy is the most basic and commonly used method for pain relief and management. Interestingly, at present, hundreds of traditional Chinese medicines have been reported to be used for pain relief, most of which are monomer preparations, which have been developed into new painkillers. Corydalis yanhusuo is a representative of one of these medicines and is available for pain relief. AIM OF THE STUDY: This study aims to determine the analgesic effect and the potential targets of the monomers derived from Corydalis yanhusuo, and to explore any possible associated cardiac risk factors. MATERIALS AND METHODS: In this study, four monomers derived from Corydalis yanhusuo (tetrahydropalmatine, corydaline, protopine, dehydrocorydaline) were tested in vivo, using the formalin-induced pain model to determine their analgesic properties. Their potential targets were also determined using whole cell patch clamp recordings and myocardial enzyme assays. RESULTS: The results showed that all monomers showed analgesic activity and inhibited the peak currents, promoted the activation and inactivation phases of Nav1.7, which indicating that Nav1.7 might be involved in the analgesic mechanism of Corydalis yanhusuo. Protopine increased the level of creatine kinase-MB (CK-MB) and inhibited the peak currents, promoted the activation and inactivation phases of Nav1.5, indicating that Nav1.5 might be involved in the cardiac risk associated with protopine treatment. CONCLUSION: These data showed that tetrahydropalmatine produced the best analgesic effect and the lowest cardiac risk. Thus, voltage gated sodium channels (VGSCs) might be the main targets associated with Corydalis yanhusuo. This study, therefore, provides valuable information for future studies and use of traditional Chines medicines for the alleviation of pain.


Asunto(s)
Analgésicos/farmacología , Corydalis/química , Medicamentos Herbarios Chinos/envenenamiento , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Analgésicos/química , Analgésicos/aislamiento & purificación , Animales , Alcaloides de Berberina/aislamiento & purificación , Alcaloides de Berberina/farmacología , Células CHO , Cricetulus , Modelos Animales de Enfermedad , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Formaldehído , Ratones , Dolor/tratamiento farmacológico , Técnicas de Placa-Clamp , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/aislamiento & purificación , Canales de Sodio Activados por Voltaje/efectos de los fármacos , Canales de Sodio Activados por Voltaje/metabolismo
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