RESUMEN
Sensing of noxious heat has been reported to be mediated by TRPV1, TRPA1, TRPM3, and ANO1 in mice, and this is redundant so that the loss of one receptor is at least partially compensated for by others. We have established an infusion-based human heat pain model. Heat-induced pain probed with antagonists for the four receptors did not match the redundancy found in mice. In healthy participants, only TRPV1 contributes to the detection of noxious heat; none of the other three receptors are involved. TRPV1 inhibition reduced the pain at all noxious temperatures, which can also be seen as an increase in the temperature that causes a particular level of pain. However, even if the TRPV1-dependent shift in heat detection is about 1°C, at the end of the temperature ramp to 52°C, most heat-induced pain remains unexplained. This difference between species reopens the quest for the molecular safety net for the detection of noxious heat in humans.
Asunto(s)
Calor , Canales Catiónicos TRPV , Sensación Térmica , Humanos , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Masculino , Adulto , Animales , Femenino , Ratones , Estudios Cruzados , Dolor , Canal Catiónico TRPA1/metabolismo , Canal Catiónico TRPA1/genética , Canal Catiónico TRPA1/antagonistas & inhibidores , Adulto JovenRESUMEN
Neuropathic pain, a common symptom of several disorders, exerts a substantial socioeconomic burden worldwide. Transient receptor potential vanilloid 1 (TRPV1), a non-selective cation channel predominantly ex-pressed in nociceptive neurons, plays a pivotal role in nociception, by detecting various endogenous and exogenous stimuli, including heat, pro-inflammatory mediators, and physical stressors. Dysregulation of TRPV1 signaling further contributes to the pathophysiology of neuropathic pain. Therefore, targeting TRPV1 is a promising strategy for developing novel analgesics with improved efficacy and safety profiles. Several pharmacological approaches to modulate TRPV1 activity, including agonists, antagonists, and biological TRPV1 RNA interference (RNAi, small interfering RNA [siRNA]) have been explored. Despite preclinical success, the clinical translation of TRPV1-targeted therapies has encountered challenges, including hyperthermia, hypothermia, pungency, and desensitization. Nevertheless, ongoing research efforts aim to refine TRPV1-targeted interventions through structural modifications, development of selective modulators, and discovery of natural, peptide-based drug candidates. Herein, we provide guidance for researchers and clinicians involved in the development of new interventions specifically targeting TRPV1 by reviewing the existing literature and highlighting current research activities. This study further discusses potential future research endeavors for enhancing the efficacy, safety, and tolerability of TRPV1 candidates, and thereby facilitates the translation of these discoveries into effective clinical interventions to alleviate neuropathic pain disorders.
Asunto(s)
Neuralgia , Canales Catiónicos TRPV , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Neuralgia/tratamiento farmacológico , Neuralgia/metabolismo , Humanos , Animales , Analgésicos/farmacología , Analgésicos/uso terapéuticoRESUMEN
Acute nociceptive pain in mice caused by subcutaneous (intraplantar) injection of TRPV1 ion channel agonist capsaicin (1.6 µg/mouse) and the effects of protein kinase A inhibitor H-89 (0.05 mg/mouse, intraplantar injection) and NMDA receptor channel antagonists MK-801 (7.5 and 15 µg/mouse, topical application) and hemantane (0.5 mg/mouse, topical application) on the pain were assessed. MK-801 and hemantane were found to reduce the duration of the pain response. H-89 did not significantly affect the pain in animals, but preliminary administration of this drug abolished the antinociceptive effect of MK-801 (7.5 µg/mouse) and weakens the effect of hemantane (0.5 mg/mouse).
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Analgésicos , Capsaicina , Maleato de Dizocilpina , Receptores de N-Metil-D-Aspartato , Animales , Capsaicina/farmacología , Ratones , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Masculino , Maleato de Dizocilpina/farmacología , Analgésicos/farmacología , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Dolor Nociceptivo/tratamiento farmacológico , Dolor Nociceptivo/inducido químicamente , Dimensión del Dolor/efectos de los fármacos , Dimensión del Dolor/métodosRESUMEN
Transient Receptor Potential Vanilloid 1 (TRPV1) plays a central role in pain sensation and is thus an attractive pharmacological drug target. SAF312 is a potent, selective, and non-competitive antagonist of TRPV1 and shows promising potential in treating ocular surface pain. However, the precise mechanism by which SAF312 inhibits TRPV1 remains poorly understood. Here, we present the cryo-EM structure of human TRPV1 in complex with SAF312, elucidating the structural foundation of its antagonistic effects on TRPV1. SAF312 binds to the vanilloid binding pocket, preventing conformational changes in S4 and S5 helices, which are essential for channel gating. Unexpectedly, a putative cholesterol was found to contribute to SAF312's inhibition. Complemented by mutagenesis experiments and molecular dynamics simulations, our research offers substantial mechanistic insights into the regulation of TRPV1 by SAF312, highlighting the interplay between the antagonist and cholesterol in modulating TRPV1 function. This work not only expands our understanding of TRPV1 inhibition by SAF312 but also lays the groundwork for further developments in the design and optimization of TRPV1-related therapies.
Asunto(s)
Colesterol , Microscopía por Crioelectrón , Simulación de Dinámica Molecular , Canales Catiónicos TRPV , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/química , Canales Catiónicos TRPV/genética , Colesterol/metabolismo , Humanos , Sitios de Unión , Células HEK293 , Unión ProteicaRESUMEN
Natural caffeic acid (CA) and its analogues have been studied for their potential applications in the treatment of various inflammatory and infectious skin diseases. However, the molecular mechanism underlying the effects of the CA remains largely unknown. Here, we report that CA and its two analogues, caffeic acid phenethyl ester (CAPE) and caffeic acid methyl caffeate (CAMC), inhibit TRPV3 currents in their concentration- and structure-dependent manners with IC50 values ranging from 102 to 410 µM. At the single-channel level, CA reduces the channel open probability and open frequency without alteration of unitary conductance. CA selectively inhibits TRPV3 relative to other subtypes of thermo-TRPs, such as TRPA1, TRPV1, TRPV4, and TRPM8. Molecular docking combined with site-specific mutagenesis reveals that a residue T636 in the Pore-loop is critical for CA binding to TRPV3. Further in vivo evaluation shows that CA significantly reverses TRPV3-mediated skin inflammation induced by skin sensitizer carvacrol. Altogether, our findings demonstrate that CA exerts its anti-inflammatory effects by selectively inhibiting TRPV3 through binding to the pocket formed by the Pore-loop and the S6. CA may serve as a lead for further modification and identification of specific TRPV3 channel inhibitors.
Asunto(s)
Ácidos Cafeicos , Simulación del Acoplamiento Molecular , Canales Catiónicos TRPV , Ácidos Cafeicos/farmacología , Ácidos Cafeicos/química , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Humanos , Animales , Ratones , Piel/metabolismo , Piel/efectos de los fármacos , Piel/patología , Cimenos/farmacología , Cimenos/química , Células HEK293 , Antiinflamatorios/farmacología , Antiinflamatorios/química , Inflamación/tratamiento farmacológico , Inflamación/metabolismoRESUMEN
Diabetic neuropathic pain (DNP) is a diabetic complication that causes severe pain and deeply impacts the quality of the sufferer's daily life. Currently, contemporary clinical treatments for DNP generally exhibit a deficiency in effectiveness. Electroacupuncture (EA) is recognized as a highly effective and safe treatment for DNP with few side effects. Regrettably, the processes via which EA alleviates DNP are still poorly characterized. Transient receptor potential vanilloid 1 (TRPV1) and phosphorylated calcium/calmodulin-dependent protein kinase II (p-CaMKII) are overexpressed on spinal cord dorsal horn (SCDH) in DNP rats, and co-localization is observed between them. Capsazepine, a TRPV1 antagonist, effectively reduced nociceptive hypersensitivity and downregulated the overexpression of phosphorylated CaMKIIα in rats with DNP. Conversely, the CaMKII inhibitor KN-93 did not have any impact on TRPV1. EA alleviated heightened sensitivity to pain caused by nociceptive stimuli and downregulated the level of TRPV1, p-CaMKIIα, and phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB) in DNP rats. Intrathecal injection of capsaicin, on the other hand, reversed the above effects of EA. These findings indicated that the CaMKII/CREB pathway on SCDH is located downstream of TRPV1 and is affected by TRPV1. EA alleviates DNP through the TRPV1-mediated CaMKII/CREB pathway.
Asunto(s)
Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina , Proteína de Unión a Elemento de Respuesta al AMP Cíclico , Neuropatías Diabéticas , Electroacupuntura , Ratas Sprague-Dawley , Canales Catiónicos TRPV , Animales , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/antagonistas & inhibidores , Electroacupuntura/métodos , Ratas , Masculino , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Neuropatías Diabéticas/terapia , Neuropatías Diabéticas/metabolismo , Capsaicina/farmacología , Capsaicina/análogos & derivados , Transducción de Señal , Asta Dorsal de la Médula Espinal/metabolismo , Bencenosulfonamidas , BencilaminasRESUMEN
AIMS: Paclitaxel (PTX) is extensively utilized in the management of diverse solid tumors, frequently resulting in paclitaxel-induced peripheral neuropathy (PIPN). The present study aimed to investigate sex differences in the behavioral manifestations and underlying pathogenesis of PIPN and search for clinically efficacious interventions. METHODS: Male and female C57BL/6 mice (5-6 weeks and 12 months, weighing 18-30 g) were intraperitoneally (i.p.) administered paclitaxel diluted in saline (NaCl 0.9%) at a dose of 2 mg/kg every other day for a total of 4 injections. Von Frey and hot plate tests were performed before and after administration to confirm the successful establishment of the PIPN model and also to evaluate the pain of PIPN and the analgesic effect of PD-L1. On day 14 after PTX administration, PD-L1 protein (10 ng/pc) was injected into the PIPN via the intrathecal (i.t.) route. To knock down TRPV1 in the spinal cord, adeno-associated virus 9 (AAV9)-Trpv1-RNAi (5 µL, 1 × 1013 vg/mL) was slowly injected via the i.t. route. Four weeks after AAV9 delivery, the downregulation of TRPV1 expression was verified by immunofluorescence staining and Western blotting. The levels of PD-L1, TRPV1 and CGRP were measured via Western blotting, RT-PCR, and immunofluorescence staining. The levels of TNF-α and IL-1ß were measured via RT-PCR. RESULTS: TRPV1 and CGRP protein and mRNA levels were higher in the spinal cords of control female mice than in those of control male mice. PTX-induced nociceptive behaviors in female PIPN mice were greater than those in male PIPN mice, as indicated by increased expression of TRPV1 and CGRP. The analgesic effects of PD-L1 on mechanical hyperalgesia and thermal sensitivity were significantly greater in female mice than in male mice, with calculated relative therapeutic levels increasing by approximately 2.717-fold and 2.303-fold, respectively. PD-L1 and CGRP were partly co-localized with TRPV1 in the dorsal horn of the mouse spinal cord. The analgesic effect of PD-L1 in PIPN mice was observed to be mediated through the downregulation of TRPV1 and CGRP expression following AAV9-mediated spinal cord specific decreased TRPV1 expression. CONCLUSIONS: PTX-induced nociceptive behaviors and the analgesic effect of PD-L1 in PIPN mice were sexually dimorphic, highlighting the significance of incorporating sex as a crucial biological factor in forthcoming mechanistic studies of PIPN and providing insights for potential sex-specific therapeutic approaches.
Asunto(s)
Antígeno B7-H1 , Péptido Relacionado con Gen de Calcitonina , Ratones Endogámicos C57BL , Paclitaxel , Enfermedades del Sistema Nervioso Periférico , Caracteres Sexuales , Canales Catiónicos TRPV , Animales , Paclitaxel/toxicidad , Masculino , Femenino , Ratones , Péptido Relacionado con Gen de Calcitonina/metabolismo , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Antígeno B7-H1/metabolismo , Enfermedades del Sistema Nervioso Periférico/inducido químicamente , Antineoplásicos Fitogénicos/toxicidad , Médula Espinal/efectos de los fármacos , Médula Espinal/metabolismo , Hiperalgesia/inducido químicamente , Hiperalgesia/tratamiento farmacológico , Hiperalgesia/metabolismoRESUMEN
Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel, which is considered a highly validated target for pain perception. Repeated activation with agonists to desensitize receptors or use the antagonists can both exert analgesic effects. In this work, two series of novel phenylpiperazine derivatives were designed, synthesized, and evaluated for the in vitro receptor inhibitory activity and in vivo analgesic activity. Among them, L-21 containing sulfonylurea group was identified with potent TRPV1 antagonistic activity and analgesic activity in various pain models. At the same time, L-21 exhibited low risk of hyperthermia side effect. These results indicated that L-21 is a promising candidate for further development of novel TRPV1 antagonist to treat pain.
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Analgésicos , Piperazinas , Canales Catiónicos TRPV , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Piperazinas/química , Piperazinas/farmacología , Piperazinas/síntesis química , Animales , Ratones , Analgésicos/farmacología , Analgésicos/química , Analgésicos/síntesis química , Humanos , Dolor/tratamiento farmacológico , Relación Estructura-Actividad , Masculino , Células HEK293 , RatasRESUMEN
Transient receptor potential vanilloid 1 (TRPV1) was reported to be a putative target for recovery from chronic pain, producing analgesic effects after its inhibition. A series of drug candidates were previously developed, without the ability to ameliorate the therapeutic outcome. Starting from previously designed compounds, derived from the hybridization of antagonist SB-705498 and partial agonist MDR-652, we performed a virtual screening on a pharmacophore model built by exploiting the Cryo-EM 3D structure of a nanomolar antagonist in complex with the human TRPV1 channel. The pharmacophore model was described by three pharmacophoric features, taking advantage of both the bioactive pose of the antagonist and the receptor exclusion spheres. The results of the screening were implemented inside a 3D-QSAR model, correlating with the negative decadic logarithm of the inhibition rate of the ligands. After the validation of the obtained 3D-QSAR model, we designed a new series of compounds by introducing key modifications on the original scaffold. Again, we determined the compounds' binding poses after alignment to the pharmacophoric model, and we predicted their inhibition rates with the validated 3D-QSAR model. The obtained values resulted in being even more promising than parent compounds, demonstrating that ongoing research still leaves much room for improvement.
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Diseño de Fármacos , Relación Estructura-Actividad Cuantitativa , Canales Catiónicos TRPV , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Humanos , Modelos Moleculares , LigandosRESUMEN
Transient receptor potential vanilloid subtype 3 (TRPV3) is an ion channel implicated in skin physiology and itch. TRPV3 inhibitors can present a novel strategy for combating debilitating itch conditions, and medicinal plants are a natural pool of such compounds. Here, we report the isolation of a TRPV3-inhibiting compound from Andrographis paniculata, a medicinal plant with anti-inflammatory properties whose bioactive components are poorly characterized in terms of molecular targets. Using 1H and 13C NMR and high-resolution mass spectrometry, the compound was identified as a labdane-type diterpenoid, 14-deoxy-11,12-didehydroandrographolide (ddA). The activity of the compound was evaluated by fluorescent calcium assay and manual whole-cell patch-clamp technique. ddA inhibited human TRPV3 in stably expressing CHO and HaCaT keratinocytes, acting selectively among other TRP channels implicated in itch and inflammation and not showing toxicity to HaCaT cells. Antipruritic effects of the compound were evaluated in scratching behavior models on ICR mice. ddA suppressed itch induced by the TRPV3 activator carvacrol. Additionally, ddA potently suppressed histamine-induced itch with efficacy comparable to loratadine, a clinically used antihistamine drug. These results suggest the potential of ddA as a possible safe and efficacious alternative for antipruritic therapy.
Asunto(s)
Andrographis , Diterpenos , Plantas Medicinales , Prurito , Canales Catiónicos TRPV , Animales , Diterpenos/farmacología , Diterpenos/química , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/efectos de los fármacos , Canales Catiónicos TRPV/metabolismo , Prurito/tratamiento farmacológico , Humanos , Ratones , Plantas Medicinales/química , Andrographis/química , Estructura Molecular , Ratones Endogámicos ICR , Queratinocitos/efectos de los fármacos , Células CHO , Cricetulus , Antipruriginosos/farmacología , Masculino , Piel/efectos de los fármacos , Células HaCaTRESUMEN
Gastrointestinal cancer is among the most common cancers worldwide. Immune checkpoint inhibitor-based cancer immunotherapy has become an innovative approach in cancer treatment; however, its efficacy in gastrointestinal cancer is limited by the absence of infiltration of immune cells within the tumor microenvironment. Therefore, it is therefore urgent to develop a novel therapeutic drug to enhance immunotherapy. In this study, we describe a previously unreported potentiating effect of Icariside I (ICA I, GH01), the main bioactive compound isolated from the Epimedium species, on anti-tumor immune responses. Mechanistically, molecular docking and SPR assay result show that ICA I binding with TRPV4. ICA I induced intracellular Ca2+ increasing and mitochondrial DNA release by targeting TRPV4, which triggered cytosolic ox-mitoDNA release. Importantly, these intracellular ox-mitoDNA fragments were taken up by immune cells in the tumor microenvironment, which amplified the immune response. Moreover, our study shows the remarkable efficacy of sequential administration of ICA I and anti-α-PD-1 mAb in advanced tumors and provides a strong scientific rationale for recommending such a combination therapy for clinical trials. ICA I enhanced the anti-tumor effects with PD-1 inhibitors by regulating the TRPV4/Ca2+/Ox-mitoDNA/cGAS/STING axis. We expect that these findings will be translated into clinical therapies, which will benefit more patients with cancer in the near future.
Asunto(s)
Flavonoides , Neoplasias Gastrointestinales , Inmunoterapia , Proteínas de la Membrana , Canales Catiónicos TRPV , Humanos , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Animales , Inmunoterapia/métodos , Línea Celular Tumoral , Neoplasias Gastrointestinales/tratamiento farmacológico , Neoplasias Gastrointestinales/inmunología , Neoplasias Gastrointestinales/patología , Flavonoides/farmacología , Microambiente Tumoral/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Ratones , Sinergismo Farmacológico , Inhibidores de Puntos de Control Inmunológico/farmacología , Femenino , Ratones Endogámicos BALB C , ADN Mitocondrial , Simulación del Acoplamiento MolecularRESUMEN
While effective analgesics, TRPV1 antagonists can dangerously alter thermoregulation. In this issue of Neuron, Huang et al.1 demonstrate that interaction with the S4-S5 linker of TRPV1 determines whether an antagonist affects core body temperature, with promising implications for analgesic development.
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Regulación de la Temperatura Corporal , Hipertermia , Canales Catiónicos TRPV , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Hipertermia/inducido químicamente , Animales , Regulación de la Temperatura Corporal/efectos de los fármacos , Regulación de la Temperatura Corporal/fisiología , Humanos , Temperatura Corporal/efectos de los fármacos , Analgésicos/farmacologíaRESUMEN
RN-9893, a TRPV4 antagonist identified by Renovis Inc., showcased notable inhibition of TRPV4 channels. This research involved synthesizing and evaluating three series of RN-9893 analogues for their TRPV4 inhibitory efficacy. Notably, compounds 1b and 1f displayed a 2.9 to 4.5-fold increase in inhibitory potency against TRPV4 (IC50 = 0.71 ± 0.21 µM and 0.46 ± 0.08 µM, respectively) in vitro, in comparison to RN-9893 (IC50 = 2.07 ± 0.90 µM). Both compounds also significantly outperformed RN-9893 in TRPV4 current inhibition rates (87.6 % and 83.2 % at 10 µM, against RN-9893's 49.4 %). For the first time, these RN-9893 analogues were profiled in an in vivo mouse model, where intraperitoneal injections of 1b or 1f at 10 mg/kg notably mitigated symptoms of acute lung injury induced by lipopolysaccharide (LPS). These outcomes indicate that compounds 1b and 1f are promising candidates for acute lung injury treatment.
Asunto(s)
Lesión Pulmonar Aguda , Bencenosulfonamidas , Sulfonamidas , Canales Catiónicos TRPV , Relación Estructura-Actividad , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Lesión Pulmonar Aguda/tratamiento farmacológico , Sulfonamidas/química , Sulfonamidas/farmacología , Sulfonamidas/síntesis química , Animales , Ratones , Humanos , Estructura Molecular , Relación Dosis-Respuesta a Droga , Lipopolisacáridos/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Masculino , Ratones Endogámicos C57BLRESUMEN
Analgesia and blood sugar control are considered as two main unmet clinical needs for diabetes related neuropathic pain patients. Transient receptor potential vanilloid type-1 (TRPV1) channel is a highly validated target for pain perception, while no TRPV1 antagonists have been approved due to hyperthermia side effects. Herein, two series of new TRPV1 antagonists with flavonoid skeleton were designed by the structure-based drug design (SBDD) strategy. After comprehensive evaluation, compound CX-3 was identified as a promising TRPV1 antagonist. CX-3 exhibited equivalent TRPV1 antagonistic activity with classical TRPV1 antagonist BCTC in vitro, and exerted better analgesic activity in vivo than that of BCTC in the formalin induced inflammatory pain model without hyperthermia risk. Moreover, CX-3 exhibited robust glucose-lowering effects and showed high selectivity over other ion channels. Overall, these findings identified a first-in-class highly selective TRPV1 antagonist CX-3, which is a promising candidate to target the pathogenesis of diabetes related neuropathic pain.
Asunto(s)
Analgésicos , Hipoglucemiantes , Canales Catiónicos TRPV , Animales , Humanos , Masculino , Ratones , Ratas , Analgésicos/farmacología , Analgésicos/química , Analgésicos/síntesis química , Relación Dosis-Respuesta a Droga , Descubrimiento de Drogas , Hipoglucemiantes/farmacología , Hipoglucemiantes/química , Hipoglucemiantes/síntesis química , Estructura Molecular , Ratas Sprague-Dawley , Relación Estructura-Actividad , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismoRESUMEN
PURPOSE: Chronic stress is a significant risk factor for mood disorders such as depression, where synaptic plasticity plays a central role in pathogenesis. Transient Receptor Potential Vanilloid Type-2 (TRPV2) Ion Channels are implicated in hypothalamic-pituitary-adrenal axis disorders. Previous proteomic analysis indicated a reduction in TRPV2 levels in the chronic unpredictable mild stress (CUMS) rat model, yet its role in synaptic plasticity during depression remains to be elucidated. This study aims to investigate TRPV2's role in depression and its underlying mechanisms. METHODS: In vivo and in vitro experiments were conducted using the TRPV2-specific agonist probenecid and ERK1/2 inhibitors SCH772984. In vivo, rats underwent six weeks of CUMS before probenecid administration. Depressive-like behaviors were assessed through behavioral tests. ELISA kits measured 5-HT, DA, NE levels in rat hippocampal tissues. Hippocampal morphology was examined via Nissl staining. In vitro, rat hippocampal neuron cell lines were treated with ERK1/2 inhibitors SCH772984 and probenecid. Western blot, immunofluorescence, immunohistochemical staining, and RT-qPCR assessed TRPV2 expression, neurogenesis-related proteins, synaptic markers, and ERK1/2-CREB-BDNF signaling proteins. RESULTS: Decreased hippocampal TRPV2 levels were observed in CUMS rats. Probenecid treatment mitigated depressive-like behavior and enhanced hippocampal 5-HT, NE, and DA levels in CUMS rats. TRPV2 activation countered CUMS-induced synaptic plasticity inhibition. Probenecid activated the ERK1/2-CREB-BDNF pathway, suggesting TRPV2's involvement in this pathway via ERK1/2. CONCLUSION: These findings indicate that TRPV2 activation offers protective effects against depressive-like behaviors and enhances hippocampal synaptic plasticity in CUMS rats via the ERK1/2-CREB-BDNF pathway. TRPV2 emerges as a potential therapeutic target for depression.
Asunto(s)
Factor Neurotrófico Derivado del Encéfalo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico , Hipocampo , Sistema de Señalización de MAP Quinasas , Plasticidad Neuronal , Ratas Sprague-Dawley , Estrés Psicológico , Canales Catiónicos TRPV , Animales , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Plasticidad Neuronal/efectos de los fármacos , Masculino , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Estrés Psicológico/complicaciones , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología , Hipocampo/metabolismo , Hipocampo/efectos de los fármacos , Ratas , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Depresión/metabolismo , Depresión/tratamiento farmacológico , Enfermedad Crónica , Probenecid/farmacologíaRESUMEN
A synthetic inhibitor of capsaicin-induced TRPV1 channel activation is called capsazepine (CPZ). In this study, we aimed to explore the effects of CPZ on hyperpolarization-activated cationic current (Ih) and voltage-gated Na + current (INa) in pituitary tumor (GH3) cells. Through patch-clamp recordings, we found that CPZ concentration-dependently inhibited Ih amplitude and slowed its activation time course. The IC50 and KD values were 3.1 and 3.16 µM, respectively. CPZ also shifted the steady-state activation curve of Ih towards a more hyperpolarized potential. However, there was no change in the gating charge of the curve. A modified Markovian model predicted the CPZ-induced decrease in the voltage-dependent hysteresis of Ih. CPZ suppressed INa in GH3 cells, without altering its activation or inactivation time course. Additionally, exposure to CPZ reduced spontaneous firing. These findings suggest that CPZ's inhibitory effects on Ih and INa are direct and not dependent on vanilloid receptor binding. This could provide light on an unidentified ionic mechanism influencing the membrane excitability of neurons and endocrine or neuroendocrine cells in vivo.
Asunto(s)
Capsaicina , Canales Catiónicos TRPV , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/efectos de los fármacos , Capsaicina/farmacología , Capsaicina/análogos & derivados , Animales , Ratas , Línea Celular Tumoral , Técnicas de Placa-Clamp , Potenciales de la Membrana/efectos de los fármacos , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Potenciales de Acción/efectos de los fármacosRESUMEN
This is the first study to analyze the anti-inflammatory and antinociceptive effect of withanicandrin, isolated from Datura Ferox leaves, and the possible mechanism of action involved in adult zebrafish (ZFa). To this end, the animals were treated intraperitoneally (i. p.) with withanicandrin (4; 20 and 40â mg/kg; 20â µL) and subjected to locomotor activity and acute toxicity. Nociception tests were also carried out with chemical agents, in addition to tests to evaluate inflammatory processes induced by κ-Carrageenan 1.5 % and a Molecular Docking study. As a result, withanicandrin reduced nociceptive behavior by capsaicin at a dose of 40â mg/kg and by acid saline at doses of 4 and 40â mg/kg, through neuromodulation of TRPV1 channels and ASICs, identified through blocking the antinociceptive effect of withanicandrin by the antagonists capsazepine and naloxone. Furthermore, withanicandrin caused an anti-inflammatory effect through the reduction of abdominal edema, absence of leukocyte infiltrate in the liver tissue and reduction of ROS in thel liver tissue and presented better affinity energy compared to control morphine (TRPV1) and ibuprofen (COX-1 and COX-2).
Asunto(s)
Analgésicos , Pez Cebra , Animales , Analgésicos/farmacología , Analgésicos/química , Analgésicos/aislamiento & purificación , Canales Iónicos Sensibles al Ácido/metabolismo , Simulación del Acoplamiento Molecular , Antiinflamatorios/farmacología , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Carragenina , Relación Estructura-Actividad , Relación Dosis-Respuesta a Droga , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Edema/tratamiento farmacológico , Edema/inducido químicamente , Hojas de la Planta/química , Estructura MolecularRESUMEN
A series of 1,4-benzoxazin-3-one analogs were investigated to discover mode-selective TRPV1 antagonists, since such antagonists are predicted to minimize target-based adverse effects. Using the high-affinity antagonist 2 as the lead structure, the structure activity relationship was studied by modifying the A-region through incorporation of a polar side chain on the benzoxazine and then by changing the C-region with a variety of substituted pyridine, pyrazole and thiazole moieties. The t-butyl pyrazole and thiazole C-region analogs provided high potency as well as mode-selectivity. Among them, antagonist 36 displayed potent and capsaicin-selective antagonism with IC50 = 2.31 nM for blocking capsaicin activation and only 47.5 % inhibition at 3 µM concentration toward proton activation, indicating that more than a 1000-fold higher concentration of 36 was required to inhibit proton activation than was required to inhibit capsaicin activation. The molecular modeling study of 36 with our homology model indicated that two π-π interactions with the Tyr511 and Phe591 residues by the A- and C-region and hydrogen bonding with the Thr550 residue by the B-region were critical for maintaining balanced and stable binding. Systemic optimization of antagonist 2, which has high-affinity but full antagonism for activators of all modes, led to the mode-selective antagonist 36 which represents a promising step in the development of clinical TRPV1 antagonists minimizing side effects such as hyperthermia and impaired heat sensation.
Asunto(s)
Benzoxazinas , Canales Catiónicos TRPV , Urea , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Relación Estructura-Actividad , Benzoxazinas/química , Benzoxazinas/farmacología , Benzoxazinas/síntesis química , Urea/análogos & derivados , Urea/química , Urea/farmacología , Urea/síntesis química , Humanos , Estructura Molecular , Animales , Capsaicina/farmacología , Capsaicina/química , Descubrimiento de Drogas , Relación Dosis-Respuesta a DrogaRESUMEN
The nonselective calcium-permeable Transient Receptor Potential Cation Channel Subfamily V Member4 (TRPV4) channel regulates various physiological activities. Dysfunction of TRPV4 is linked to many severe diseases, including edema, pain, gastrointestinal disorders, lung diseases, and inherited neurodegeneration. Emerging TRPV4 antagonists show potential clinical benefits. However, the molecular mechanisms of TRPV4 antagonism remain poorly understood. Here, cryo-electron microscopy (cryo-EM) structures of human TRPV4 are presented in-complex with two potent antagonists, revealing the detailed binding pockets and regulatory mechanisms of TRPV4 gating. Both antagonists bind to the voltage-sensing-like domain (VSLD) and stabilize the channel in closed states. These two antagonists induce TRPV4 to undergo an apparent fourfold to twofold symmetry transition. Moreover, it is demonstrated that one of the antagonists binds to the VSLD extended pocket, which differs from the canonical VSLD pocket. Complemented with functional and molecular dynamics simulation results, this study provides crucial mechanistic insights into TRPV4 regulation by small-molecule antagonists, which may facilitate future drug discovery targeting TRPV4.
Asunto(s)
Microscopía por Crioelectrón , Canales Catiónicos TRPV , Canales Catiónicos TRPV/antagonistas & inhibidores , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/química , Canales Catiónicos TRPV/genética , Humanos , Microscopía por Crioelectrón/métodos , Simulación de Dinámica Molecular , Sitios de UniónRESUMEN
OBJECTIVES: To design and synthesize peptide inhibitors targeting transient receptor potential vanilloid 1 (TRPV1) ion channel, and to validate their function. METHODS: Based on previous studies on the relation of molecular structure and function of red head toxin (RhTx), a series of peptides were rationally designed and synthesized, with positive charged amino acids linked to the N terminus of RhTx. These Nplus-RhTx peptides were functionally validated by patch-clamp recordings in live cells. RESULTS: Among the 8 synthesized Nplus-RhTx peptides, four inhibited TRPV1 ion channel activated by capsaicin with IC50 of (188.3±4.7), (193.6±18.0), (282.8±11.9) and (299.5±6.4) µmol/L, respectively. CONCLUSIONS: It is feasible to develop TRPV1 peptide inhibitors by using rational design based on N terminal residues of RhTx.