RESUMEN
Metabolic regulation has been recognized as a powerful principle guiding immune responses. Inflammatory macrophages undergo extensive metabolic rewiring 1 marked by the production of substantial amounts of itaconate, which has recently been described as an immunoregulatory metabolite 2 . Itaconate and its membrane-permeable derivative dimethyl itaconate (DI) selectively inhibit a subset of cytokines 2 , including IL-6 and IL-12 but not TNF. The major effects of itaconate on cellular metabolism during macrophage activation have been attributed to the inhibition of succinate dehydrogenase2,3, yet this inhibition alone is not sufficient to account for the pronounced immunoregulatory effects observed in the case of DI. Furthermore, the regulatory pathway responsible for such selective effects of itaconate and DI on the inflammatory program has not been defined. Here we show that itaconate and DI induce electrophilic stress, react with glutathione and subsequently induce both Nrf2 (also known as NFE2L2)-dependent and -independent responses. We find that electrophilic stress can selectively regulate secondary, but not primary, transcriptional responses to toll-like receptor stimulation via inhibition of IκBζ protein induction. The regulation of IκBζ is independent of Nrf2, and we identify ATF3 as its key mediator. The inhibitory effect is conserved across species and cell types, and the in vivo administration of DI can ameliorate IL-17-IκBζ-driven skin pathology in a mouse model of psoriasis, highlighting the therapeutic potential of this regulatory pathway. Our results demonstrate that targeting the DI-IκBζ regulatory axis could be an important new strategy for the treatment of IL-17-IκBζ-mediated autoimmune diseases.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Proteínas I-kappa B/metabolismo , Succinatos/metabolismo , Animales , Células Cultivadas , Citocinas/inmunología , Citocinas/metabolismo , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Glutatión/metabolismo , Humanos , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Interleucina-6/metabolismo , Queratinocitos/efectos de los fármacos , Queratinocitos/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Factor 2 Relacionado con NF-E2/metabolismo , Psoriasis/tratamiento farmacológico , Psoriasis/patología , Estrés Fisiológico/efectos de los fármacos , Succinatos/administración & dosificación , Succinatos/química , Succinatos/farmacología , Succinatos/uso terapéutico , Receptores Toll-Like/inmunologíaRESUMEN
Previous infection with SARS-CoV-2, the virus that causes COVID-19, has been estimated to confer up to 90% protection against reinfection, although this protection was lower against the Omicron variant compared with that against other SARS-CoV-2 variants (1-3). A test-negative design was used to estimate effectiveness of COVID-19 mRNA vaccines in preventing subsequent COVID-19-associated hospitalization among adults aged ≥18 years with a previous positive nucleic acid amplification test (NAAT) or diagnosis of COVID-19. The analysis used data from Cosmos, an electronic health record (EHR)-aggregated data set (4), and compared vaccination status of 3,761 case-patients (positive NAAT result associated with hospitalization) with 7,522 matched control-patients (negative NAAT result). After previous SARS-CoV-2 infection, estimated vaccine effectiveness (VE) against COVID-19-associated hospitalization was 47.5% (95% CI = 38.8%-54.9%) after 2 vaccine doses and 57.8% (95% CI = 32.1%-73.8%) after a booster dose during the Delta-predominant period (June 20-December 18, 2021), and 34.6% (95% CI = 25.5%-42.5%) after 2 doses and 67.6% (95% CI = 61.4%-72.8%) after a booster dose during the Omicron-predominant period (December 19, 2021-February 24, 2022). Vaccination provides protection against COVID-19-associated hospitalization among adults with previous SARS-CoV-2 infection, with the highest level of protection conferred by a booster dose. All eligible persons, including those with previous SARS-CoV-2 infection, should stay up to date with vaccination to prevent COVID-19-associated hospitalization.
Asunto(s)
COVID-19 , SARS-CoV-2 , Adolescente , Adulto , COVID-19/epidemiología , COVID-19/prevención & control , Hospitalización , Humanos , ARN Mensajero , Estados Unidos/epidemiología , VacunaciónRESUMEN
The voltage-gated sodium channel NaV1.7 has received much attention from the scientific community due to compelling human genetic data linking gain- and loss-of-function mutations to pain phenotypes. Despite this genetic validation of NaV1.7 as a target for pain, high quality pharmacological tools facilitate further understanding of target biology, establishment of target coverage requirements and subsequent progression into the clinic. Within the sulfonamide class of inhibitors, reduced potency on rat NaV1.7 versus human NaV1.7 was observed, rendering in vivo rat pharmacology studies challenging. Herein, we report the discovery and optimization of novel benzoxazine sulfonamide inhibitors of human, rat and mouse NaV1.7 which enabled pharmacological assessment in traditional behavioral rodent models of pain and in turn, established a connection between formalin-induced pain and histamine-induced pruritus in mice. The latter represents a simple and efficient means of measuring target engagement.
Asunto(s)
Benzoxazinas/química , Benzoxazinas/farmacología , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Sulfonamidas/química , Sulfonamidas/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Analgésicos/química , Analgésicos/farmacocinética , Analgésicos/farmacología , Analgésicos/uso terapéutico , Animales , Benzoxazinas/farmacocinética , Benzoxazinas/uso terapéutico , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Simulación del Acoplamiento Molecular , Dolor/tratamiento farmacológico , Dolor/metabolismo , Ratas , Ratas Sprague-Dawley , Sulfonamidas/farmacocinética , Sulfonamidas/uso terapéutico , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacocinética , Bloqueadores del Canal de Sodio Activado por Voltaje/uso terapéuticoRESUMEN
One of the challenges for targeting B-Raf(V600E) with small molecule inhibitors had been achieving adequate selectivity over the wild-type protein B-Raf(WT), as inhibition of the latter has been associated with hyperplasia in normal tissues. Recent studies suggest that B-Raf inhibitors inducing the 'DFG-in/αC-helix-out' conformation (Type IIB) likely will exhibit improved selectivity for B-Raf(V600E). To explore this hypothesis, we transformed Type IIA inhibitor (1) into a series of Type IIB inhibitors (sulfonamides and sulfamides 4-6) and examined the SAR. Three selectivity indices were introduced to facilitate the analyses: the B-Raf(V600E)/B-Raf(WT) biochemical ((b)S), cellular ((c)S) selectivity, and the phospho-ERK activation ((p)A). Our data indicates that α-branched sulfonamides and sulfamides show higher selectivities than the linear derivatives. We rationalized this finding based on analysis of structural information from the literature and provided evidence for a monomeric B-Raf-inhibitor complex previously hypothesized to be responsible for the desired B-Raf(V600E) selectivity.
Asunto(s)
Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Purinas/química , Purinas/farmacología , Piridinas/química , Piridinas/farmacología , Aminación , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Modelos Moleculares , Mutación Puntual , Conformación Proteica en Hélice alfa/efectos de los fármacos , Proteínas Proto-Oncogénicas B-raf/química , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo , Relación Estructura-ActividadRESUMEN
Herein the discovery of a novel class of aminoheterocyclic Na(v)1.7 antagonists is reported. Hit compound 1 was potent but suffered from poor pharmacokinetics and selectivity. The compact structure of 1 offered a modular synthetic strategy towards a broad structure-activity relationship analysis. This analysis led to the identification of aminopyrazine 41, which had vastly improved hERG selectivity and pharmacokinetic properties.
Asunto(s)
Pirazinas/química , Pirazinas/farmacología , Bloqueadores de los Canales de Sodio/química , Bloqueadores de los Canales de Sodio/farmacología , Canales de Sodio/metabolismo , Aminas/química , Aminas/metabolismo , Aminas/farmacocinética , Aminas/farmacología , Animales , Descubrimiento de Drogas , Concentración 50 Inhibidora , Masculino , Canal de Sodio Activado por Voltaje NAV1.7 , Plasma/metabolismo , Pirazinas/metabolismo , Pirazinas/farmacocinética , Ratas , Ratas Sprague-Dawley , Bloqueadores de los Canales de Sodio/metabolismo , Bloqueadores de los Canales de Sodio/farmacocinética , Relación Estructura-ActividadRESUMEN
Screening of the Amgen compound library led to the identification of 2-phenylamino-6-cyano-1H-benzimidazole 1a as a potent CK1 gamma inhibitor with excellent kinase selectivity and unprecedented CK1 isoform selectivity. Further structure-based optimization of this series resulted in the discovery of 1h which possessed good enzymatic and cellular potency, excellent CK1 isoform and kinase selectivity, and acceptable pharmacokinetic properties.
Asunto(s)
Bencimidazoles/química , Bencimidazoles/farmacología , Quinasa de la Caseína I/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Animales , Bencimidazoles/farmacocinética , Sitios de Unión , Quinasa de la Caseína I/química , Quinasa de la Caseína I/metabolismo , Humanos , Ratones , Modelos Moleculares , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Inhibidores de Proteínas Quinasas/farmacocinética , Ratas , Relación Estructura-Actividad , beta Catenina/metabolismoRESUMEN
Substitution mutations in the BRAF serine/threonine kinase are found in a variety of human cancers. Such mutations occur in approximately 70% of human malignant melanomas, and a single hyperactivating V600E mutation is found in the activation segment of the kinase domain and accounts for more than 90% of these mutations. Given this correlation, the molecular mechanism for BRAF regulation as well as oncogenic activation has attracted considerable interest, and activated forms of BRAF, such as BRAF(V600E), have become attractive targets for small molecule inhibition. Here we report on the identification and subsequent optimization of a potent BRAF inhibitor, CS292, based on an organometallic kinase inhibitor scaffold. A cocrystal structure of CS292 in complex with the BRAF kinase domain reveals that CS292 binds to the ATP binding pocket of the kinase and is an ATP competitive inhibitor. The structure of the kinase-inhibitor complex also demonstrates that CS292 binds to BRAF in an active conformation and suggests a mechanism for regulation of BRAF by phosphorylation and BRAF(V600E) oncogene-induced activation. The structure of CS292 bound to the active form of the BRAF kinase also provides a novel scaffold for the design of BRAF(V600E) oncogene selective BRAF inhibitors for therapeutic application.
Asunto(s)
Compuestos Organometálicos/química , Inhibidores de Proteínas Quinasas/química , Proteínas Proto-Oncogénicas B-raf/química , Rutenio/química , Animales , Bencenosulfonatos/química , Bencenosulfonatos/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cristalografía por Rayos X , Humanos , Ligandos , Ratones , Modelos Moleculares , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Niacinamida/análogos & derivados , Compuestos Organometálicos/metabolismo , Compuestos de Fenilurea , Conformación Proteica , Inhibidores de Proteínas Quinasas/metabolismo , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/metabolismo , Piridinas/química , Piridinas/metabolismo , SorafenibRESUMEN
Organometallic pyridocarbazole scaffolds are investigated as protein kinase inhibitors. Whereas our previous designs employed solely a maleimide pharmacophore for achieving the two crucial canonical hydrogen bonds to the hinge region of the ATP binding site, we have now extended our investigations to include the related lactam metallo-pyridocarbazoles. The synthetic access of the two regioisomeric lactam pyridocarbazoles is described, and the distinct biological properties of the two lactam scaffolds are revealed by employing a ruthenium half sandwich complex as a model system, resulting in organometallic lead structures for the inhibition of the protein kinases TrkA and CLK2. These new lactam metallo-pyridocarbazoles expand our existing molecular toolbox and assist toward the generation of metal complex scaffolds as lead structures for the design of selective inhibitors for numerous kinases of the human kinome.
Asunto(s)
Carbazoles/química , Imidas/química , Lactamas/química , Inhibidores de Proteínas Quinasas/química , Piridonas/química , Carbazoles/síntesis química , Diseño de Fármacos , Humanos , Metales , Compuestos Organometálicos/química , Inhibidores de Proteínas Quinasas/síntesis química , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Piridonas/síntesis química , Receptor trkA/antagonistas & inhibidores , Rutenio/químicaRESUMEN
Unlike other tumors, melanomas harbor wild-type (WT) p53 but exhibit impaired p53-dependent apoptosis. The mechanisms for the impaired p53 activation are poorly understood but may be linked to the high expression of the p53 suppressor Mdm2, which is found in >50% of melanoma lesions. Here, we describe an organometallic glycogen synthase kinase 3beta (GSK3beta) inhibitor (DW1/2) as a potent activator of p53 and inducer of cell death in otherwise highly chemoresistant melanoma cells. Using RNA interference and pharmacologic approaches, we show that p53 is required for the cytotoxic effects of this organometallic inhibitor. The DW1/2 compound was barely able to induce cell death in melanoma cells with p53 mutations, further confirming the requirement for p53-WT in the cytotoxic effects of the GSK3beta inhibition. Mechanistic analysis of the p53-dependent cell death indicated an apoptotic mechanism involving depolarization of mitochondrial membrane potential, caspase cleavage, and elevated NOXA expression. The effect of p53 was not simply due to passive up-regulation of protein expression as adenoviral-mediated overexpression of p53 was not able to induce cell death. Treatment of melanoma cells with DW1/2 was instead found to decrease levels of Mdm2 and Mdm4. The importance of Mdm2 down-regulation in DW1/2-induced apoptosis was confirmed by treating the p53-WT cells with the p53/Mdm2 antagonist Nutlin-3. Taken together, our data provide a new strategy for the pharmacologic activation of p53 in melanoma, which may be a viable approach for overcoming apoptotic resistance in melanoma and offer new hope for rational melanoma therapy.
Asunto(s)
Apoptosis/efectos de los fármacos , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Melanoma/tratamiento farmacológico , Compuestos Organometálicos/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Proteína p53 Supresora de Tumor/metabolismo , Apoptosis/fisiología , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Humanos , Melanoma/metabolismo , Melanoma/patología , Mitocondrias/efectos de los fármacos , Mitocondrias/fisiología , Rutenio/química , Rutenio/farmacología , Proteína p53 Supresora de Tumor/biosíntesis , Regulación hacia ArribaRESUMEN
Glycine receptors (GlyRs) are pentameric glycine-gated chloride ion channels that are enriched in the brainstem and spinal cord where they have been demonstrated to play a role in central nervous system (CNS) inhibition. Herein we describe two novel classes of glycine receptor potentiators that have been developed using similarity- and property-guided scaffold hopping enabled by parallel synthesis and pharmacophore-based virtual screening strategies. This effort resulted in the identification of novel, efficient and modular leads having favorable in vitro ADME profiles and high CNS multi-parameter optimization (MPO) scores, exemplified by azetidine sulfonamide 19 and aminothiazole sulfone (ent2)-20.
Asunto(s)
Descubrimiento de Drogas , Receptores de Glicina/antagonistas & inhibidores , Sulfonamidas/farmacología , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Sulfonamidas/químicaRESUMEN
Current therapies to treat persistent pain and neuropathic pain are limited by poor efficacy, side effects and risk of addiction. Here, we present a novel class of potent selective, central nervous system (CNS)-penetrant potentiators of glycine receptors (GlyRs), ligand-gated ion channels expressed in the CNS. AM-1488 increased the response to exogenous glycine in mouse spinal cord and significantly reversed mechanical allodynia induced by nerve injury in a mouse model of neuropathic pain. We obtained an X-ray crystal structure of human homopentameric GlyRα3 in complex with AM-3607, a potentiator of the same class with increased potency, and the agonist glycine, at 2.6-Å resolution. AM-3607 binds a novel allosteric site between subunits, which is adjacent to the orthosteric site where glycine binds. Our results provide new insights into the potentiation of cysteine-loop receptors by positive allosteric modulators and hold promise in structure-based design of GlyR modulators for the treatment of neuropathic pain.
Asunto(s)
Receptores de Glicina/química , Regulación Alostérica , Sitios de Unión , Unión Competitiva , Cristalografía por Rayos X , Glicina/química , Células HEK293 , Humanos , Enlace de Hidrógeno , Modelos Moleculares , Unión Proteica , Conformación Proteica en Hélice alfa , Dominios Proteicos , Subunidades de Proteína/químicaRESUMEN
Current pain therapeutics suffer from undesirable psychotropic and sedative side effects, as well as abuse potential. Glycine receptors (GlyRs) are inhibitory ligand-gated ion channels expressed in nerves of the spinal dorsal horn, where their activation is believed to reduce transmission of painful stimuli. Herein, we describe the identification and hit-to-lead optimization of a novel class of tricyclic sulfonamides as allosteric GlyR potentiators. Initial optimization of high-throughput screening (HTS) hit 1 led to the identification of 3, which demonstrated ex vivo potentiation of glycine-activated current in mouse dorsal horn neurons from spinal cord slices. Further improvement of potency and pharmacokinetics produced in vivo proof-of-concept tool molecule 20 (AM-1488), which reversed tactile allodynia in a mouse spared-nerve injury (SNI) model. Additional structural optimization provided highly potent potentiator 32 (AM-3607), which was cocrystallized with human GlyRα3cryst to afford the first described potentiator-bound X-ray cocrystal structure within this class of ligand-gated ion channels (LGICs).
Asunto(s)
Receptores de Glicina/agonistas , Sulfonamidas/farmacología , Animales , Células HEK293 , Humanos , Técnicas In Vitro , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
Several reports have recently emerged regarding the identification of heteroarylsulfonamides as NaV1.7 inhibitors that demonstrate high levels of selectivity over other NaV isoforms. The optimization of a series of internal NaV1.7 leads that address a number of metabolic liabilities including bioactivation, PXR activation, as well as CYP3A4 induction and inhibition led to the identification of potent and selective inhibitors that demonstrated favorable pharmacokinetic profiles and were devoid of the aforementioned liabilities. The key to achieving this within a series prone to transporter-mediated clearance was the identification of a small range of optimal cLogD values and the discovery of subtle PXR SAR that was not lipophilicity dependent. This enabled the identification of compound 20, which was advanced into a target engagement pharmacodynamic model where it exhibited robust reversal of histamine-induced scratching bouts in mice.
Asunto(s)
Isoquinolinas/química , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Sulfonamidas/química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Animales , Línea Celular , Citocromo P-450 CYP3A/biosíntesis , Inhibidores del Citocromo P-450 CYP3A/química , Inhibidores del Citocromo P-450 CYP3A/farmacocinética , Inhibidores del Citocromo P-450 CYP3A/farmacología , Perros , Inducción Enzimática , Histamina , Humanos , Isoquinolinas/administración & dosificación , Isoquinolinas/farmacocinética , Masculino , Ratones Endogámicos C57BL , Receptor X de Pregnano , Prurito/inducido químicamente , Prurito/prevención & control , Ratas , Receptores de Esteroides/agonistas , Relación Estructura-Actividad , Sulfonamidas/administración & dosificación , Sulfonamidas/farmacocinética , Sulfonamidas/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacocinética , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacologíaRESUMEN
[This corrects the article DOI: 10.1021/acsmedchemlett.6b00243.].
RESUMEN
Cyclopentadienyl half-sandwich ruthenium complexes have been demonstrated to be promising scaffolds as protein kinase inhibitors. In order to rapidly identify derivatives which display modified pharmacological properties, we developed the synthesis of an organoruthenium compound bearing an N-succinimidyl ester at the cyclopentadienyl moiety. The quenching of this activated ester with a library of primary amines, followed by testing of the resulting amide library, led to the identification of organometallic Pim-1 and GSK-3 inhibitors with improved potencies and kinase selectivities. [structure: see text].
Asunto(s)
Ciclopentanos/química , Ésteres/química , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Compuestos de Rutenio/síntesis química , Compuestos de Rutenio/farmacología , Succinimidas/química , Aminas/síntesis química , Cromatografía Líquida de Alta Presión , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Cinética , Proteínas Proto-Oncogénicas c-pim-1/antagonistas & inhibidores , Estereoisomerismo , Especificidad por SustratoRESUMEN
The majority of potent and selective hNaV1.7 inhibitors possess common pharmacophoric features that include a heteroaryl sulfonamide headgroup and a lipophilic aromatic tail group. Recently, reports of similar aromatic tail groups in combination with an acyl sulfonamide headgroup have emerged, with the acyl sulfonamide bestowing levels of selectivity over hNaV1.5 comparable to the heteroaryl sulfonamide. Beginning with commercially available carboxylic acids that met selected pharmacophoric requirements in the lipophilic tail, a parallel synthetic approach was applied to rapidly generate the derived acyl sulfonamides. A biaryl acyl sulfonamide hit from this library was elaborated, optimizing for potency and selectivity with attention to physicochemical properties. The resulting novel leads are potent, ligand and lipophilic efficient, and selective over hNaV1.5. Representative lead 36 demonstrates selectivity over other human NaV isoforms and good pharmacokinetics in rodents. The biaryl acyl sulfonamides reported herein may also offer ADME advantages over known heteroaryl sulfonamide inhibitors.
Asunto(s)
Benzamidas/química , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Sulfonamidas/química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Animales , Benzamidas/síntesis química , Benzamidas/farmacocinética , Benzamidas/farmacología , Línea Celular , Femenino , Histamina , Humanos , Masculino , Ratones Endogámicos C57BL , Microsomas Hepáticos/metabolismo , Simulación del Acoplamiento Molecular , Prurito/inducido químicamente , Prurito/tratamiento farmacológico , Ensayo de Unión Radioligante , Ratas , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Sulfonamidas/farmacocinética , Sulfonamidas/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/síntesis química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacocinética , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacologíaRESUMEN
Human genetic evidence has identified the voltage-gated sodium channel NaV1.7 as an attractive target for the treatment of pain. We initially identified naphthalene sulfonamide 3 as a potent and selective inhibitor of NaV1.7. Optimization to reduce biliary clearance by balancing hydrophilicity and hydrophobicity (Log D) while maintaining NaV1.7 potency led to the identification of quinazoline 16 (AM-2099). Compound 16 demonstrated a favorable pharmacokinetic profile in rat and dog and demonstrated dose-dependent reduction of histamine-induced scratching bouts in a mouse behavioral model following oral dosing.
RESUMEN
While genetic evidence shows that the Nav1.7 voltage-gated sodium ion channel is a key regulator of pain, it is unclear exactly how Nav1.7 governs neuronal firing and what biophysical, physiological, and distribution properties of a pharmacological Nav1.7 inhibitor are required to produce analgesia. Here we characterize a series of aminotriazine inhibitors of Nav1.7 in vitro and in rodent models of pain and test the effects of the previously reported "compound 52" aminotriazine inhibitor on the spiking properties of nociceptors in vivo. Multiple aminotriazines, including some with low terminal brain to plasma concentration ratios, showed analgesic efficacy in the formalin model of pain. Effective concentrations were consistent with the in vitro potency as measured on partially-inactivated Nav1.7 but were far below concentrations required to inhibit non-inactivated Nav1.7. Compound 52 also reversed thermal hyperalgesia in the complete Freund's adjuvant (CFA) model of pain. To study neuronal mechanisms, electrophysiological recordings were made in vivo from single nociceptive fibers from the rat tibial nerve one day after CFA injection. Compound 52 reduced the spontaneous firing of C-fiber nociceptors from approximately 0.7 Hz to 0.2 Hz and decreased the number of action potentials evoked by suprathreshold tactile and heat stimuli. It did not, however, appreciably alter the C-fiber thresholds for response to tactile or thermal stimuli. Surprisingly, compound 52 did not affect spontaneous activity or evoked responses of Aδ-fiber nociceptors. Results suggest that inhibition of inactivated states of TTX-S channels, mostly likely Nav1.7, in the peripheral nervous system produces analgesia by regulating the spontaneous discharge of C-fiber nociceptors.
Asunto(s)
Analgésicos/uso terapéutico , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Fibras Nerviosas Amielínicas/metabolismo , Nociceptores/metabolismo , Dolor/tratamiento farmacológico , Tetrodotoxina/farmacología , Potenciales de Acción/fisiología , Analgesia/métodos , Animales , Formaldehído/farmacología , Adyuvante de Freund/farmacología , Masculino , Dolor/inducido químicamente , Manejo del Dolor , Dimensión del Dolor/métodos , Técnicas de Placa-Clamp , Ratas , Ratas Sprague-Dawley , Bloqueadores de los Canales de Sodio/farmacologíaRESUMEN
Potent and selective inhibitors of tankyrases have recently been characterized to bind to an induced pocket. Here we report the identification of a novel potent and selective tankyrase inhibitor that binds to both the nicotinamide pocket and the induced pocket. The crystal structure of human TNKS1 in complex with this "dual-binder" provides a molecular basis for their strong and specific interactions and suggests clues for the further development of tankyrase inhibitors.