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The gene KCNT1 encodes the sodium-activated potassium channel KNa1.1 (Slack, Slo2.2). Variants in the KCNT1 gene induce a gain-of-function (GoF) phenotype in ionic currents and cause a spectrum of intractable neurological disorders in infants and children, including epilepsy of infancy with migrating focal seizures (EIMFS) and autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). Effective treatment options for KCNT1-related disease are absent, and novel therapies are urgently required. We describe the development of a novel class of oxadiazole KNa1.1 inhibitors, leading to the discovery of compound 31 that reduced seizures and interictal spikes in a mouse model of KCNT1 GoF.

Pitt Hopkins Syndrome (PTHS) is a rare genetic disorder caused by mutations of a specific gene, transcription factor 4 (TCF4), located on chromosome 18. PTHS results in individuals that have moderate to severe intellectual disability, with most exhibiting psychomotor delay. PTHS also exhibits features of autistic spectrum disorders, which are characterized by the impaired ability to communicate and socialize. PTHS is comorbid with a higher prevalence of epileptic seizures which can be present from birth or which commonly develop in childhood. Attenuated or absent TCF4 expression results in increased translation of peripheral ion channels Kv7.1 and Nav1.8 which triggers an increase in after-hyperpolarization and altered firing properties. We now describe a high throughput screen (HTS) of 1280 approved drugs and machine learning models developed from this data. The ion channels were expressed in either CHO (KV7.1) or HEK293 (Nav1.8) cells and the HTS used either 86Rb+ efflux (KV7.1) or a FLIPR assay (Nav1.8). The HTS delivered 55 inhibitors of Kv7.1 (4.2% hit rate) and 93 inhibitors of Nav1.8 (7.2% hit rate) at a screening concentration of 10 μM. These datasets also enabled us to generate and validate Bayesian machine learning models for these ion channels. We also describe a structure activity relationship for several dihydropyridine compounds as inhibitors of Nav1.8. This work could lead to the potential repurposing of nicardipine or other dihydropyridine calcium channel antagonists as potential treatments for PTHS acting via Nav1.8, as there are currently no approved treatments for this rare disorder.

TRPA1, a member of the transient receptor potential channel (TRP) family, is genetically linked to pain in humans, and small molecule inhibitors are efficacious in preclinical animal models of inflammatory pain. These findings have driven significant interest in development of selective TRPA1 inhibitors as potential analgesics. The majority of TRPA1 inhibitors characterized to date have been reported to interact with the S5 transmembrane helices forming part of the pore region of the channel. However, the development of many of these inhibitors as clinical drug candidates has been prevented by high lipophilicity, low solubility, and poor pharmacokinetic profiles. Identification of alternate compound interacting sites on TRPA1 provides the opportunity to develop structurally distinct modulators with novel structure-activity relationships and more desirable physiochemical properties. In this paper, we have identified a previously undescribed potent and selective small molecule thiadiazole structural class of TRPA1 inhibitor. Using species ortholog chimeric and mutagenesis strategies, we narrowed down the site of interaction to ankyrinR #6 within the distal N-terminal region of TRPA1. To identify the individual amino acid residues involved, we generated a computational model of the ankyrinR domain. This model was used predictively to identify three critical amino acids in human TRPA1, G238, N249, and K270, which were confirmed by mutagenesis to account for compound activity. These findings establish a small molecule interaction region on TRPA1, expanding potential avenues for developing TRPA1 inhibitor analgesics and for probing the mechanism of channel gating.

A case study for Workshop on Open Source Solutions for the Internet of Things. ICTP, Trieste, Italy. http://indico.ictp.it/event/7972/

Las redes IEEE 802.11 constituyen actualmente una de las opciones más populares para tener acceso inalámbrico a la Internet. Debido a su auge, los dispositivos en despliegues cada vez más amplios, heterogéneos y caóticos tienen que cumplir con un proceso de descubrimiento y conexión complejo, probando activamente todos los canales en la banda ISM. Esto con el fin de obtener información de todos los puntos de acceso que le permitan posteriormente asociarse a una red. El estándar IEEE 802.11 no especifica ningún método para escanear los canales en la búsqueda de redes alcanzables. En este sentido, este trabajo describe un enfoque práctico para el descubrimiento de redes IEEE 802.11 en el contexto de la Internet del futuro. En primer lugar, se presenta el diseño y construcción de un sniffer de redes IEEE 802.11 que puede escuchar, simultáneamente, a los 11 canales de la banda ISM. Con este sniffer, hacemos ingeniería inversa de los algoritmos de escaneo implementados en dispositivos móviles con interfaces IEEE 802.11. En segundo lugar, se discute a partir de una técnica de inteligencia computacional, un enfoque para encontrar la configuración de secuencias de escaneo óptimas en redes IEEE 802.11 espontáneas. Hemos abordado el problema usando la optimización multi-objetivo, es decir, el compromiso entre una tasa alta de descubrimiento de puntos de acceso y la duración del proceso de escaneo. El algoritmo cultural se implementó en código abierto y se apoya en un emulador de escaneo basado en una extensa campaña de mediciones experimentales. Los resultados de la aplicación del algoritmo cultural arrojaron secuencias de escaneo que proporcionan mejoras en el desempeño de la búsqueda entre un 230% y 600% con respecto a una gama de dispositivos tipificados a partir del sniffer multicanal. Finalmente, y de manera prospectiva, se presenta un bosquejo de un sistema de descubrimiento asistido e inteligente. A través de este sistema, se derivan secuencias de escaneo óptimas en redes de acceso comunitario, que permitan a los dispositivos inalámbricos encontrar los puntos de acceso disponibles y eventualmente, asociarse a estas redes de una manera eficiente. Universidad de Los Andes aaraujo@cenditel.gob.ve Magister Scientiae en Computación

Na(v)1.8 (also known as PN3) is a tetrodotoxin-resistant (TTx-r) voltage-gated sodium channel (VGSC) that is highly expressed on small diameter sensory neurons. It has been implicated in the pathophysiology of inflammatory and neuropathic pain, and we envisioned that selective blockade of Na(v)1.8 would be analgesic, while reducing adverse events typically associated with non-selective VGSC blocking therapeutic agents. Herein, we describe the preparation and characterization of a series of 6-aryl-2-pyrazinecarboxamides, which are potent blockers of the human Na(v)1.8 channel and also block TTx-r sodium currents in rat dorsal root ganglia (DRG) neurons. Selected derivatives display selectivity versus human Na(v)1.2. We further demonstrate that an example from this series is orally bioavailable and produces antinociceptive activity in vivo in a rodent model of neuropathic pain following oral administration.

A series of aryl-substituted nicotinamide derivatives with selective inhibitory activity against the Na(v)1.8 sodium channel is reported. Replacement of the furan nucleus and homologation of the anilide linker in subtype-selective blocker A-803467 (1) provided potent, selective derivatives with improved aqueous solubility and oral bioavailability. Representative compounds from this series displayed efficacy in rat models of inflammatory and neuropathic pain.

BACKGROUND A non-opioid receptor-mediated inhibition of sodium channels in dorsal root ganglia (DRGs) by kappa-opioid receptor agonists (kappa-ORAs) has been reported to contribute to the antinociceptive actions in animals and humans. In this study, we examined structurally diverse kappa-ORAs for their abilities to inhibit tetrodotoxin-resistant (TTX-r) sodium channels in adult rat DRGs. METHODS Whole-cell recordings of TTX-r sodium currents were performed on cultured adult rat DRGs. Structurally diverse kappa-ORAs were studied for their abilities to inhibit TTX-r sodium channels. RESULTS The racemic kappa-ORA, (+/-)U50,488, inhibited TTX-r sodium currents in a voltage-dependent manner, yielding IC(50) values of 49 and 8 muM, at prepulse potentials of -100 and -40 mV, respectively. Furthermore, we found that both the kappa-ORA U50,488 active enantiomer 1S,2S U50,488 and the inactive enantiomer 1R,2R U50,488 were equally potent inhibitors of TTX-r sodium currents. Structurally related kappa-ORAs, such as BRL 52537 and ICI 199,441 also inhibited TTX-r sodium currents. However, sodium channel inhibition and kappa-opioid receptor agonism have a distinct structure-activity relationship because another kappa-ORA (ICI 204,488) was inactive versus TTX-r sodium channels. We further investigated the sodium channel block of this class of compounds by studying (+/-)U50,488. (+/-)U50,488 was found to preferentially interact with the slow inactivated state of TTX-r sodium channels and to retard recovery from inactivation. CONCLUSION Our results suggest that TTX-r sodium channels can be inhibited by many kappa-ORAs via an opioid receptor-independent mechanism. Although the potency for sodium channel inhibition is typically much less than apparent affinity for opioid receptors, sodium channel block may still contribute to the antinociceptive effects of this class of compounds.

Voltage dependent sodium channels are widely recognized as valuable targets for the development of therapeutic interventions for neuroexcitatory disorders such as epilepsy and pain as well as cardiac arrhythmias. An ongoing challenge for sodium channel drug discovery is the ability to readily evaluate state dependent interactions, which are known to underlie inhibition by many clinically used local anesthetic, antiepileptic and antiarrhythmic sodium channel blockers. While patch-clamp electrophysiology is still considered the most effective way of measuring ion channel function and pharmacology, it does not have the throughput to be useful in early stages of drug discovery in which there is often a need to evaluate many thousands to hundreds of thousands of compounds. Fortunately over the past five years, there has been significant progress in developing much higher throughput electrophysiology platforms like the PatchXpressTM and Ion- WorksTM, which are now widely used in drug discovery. This review highlights the strengths and weaknesses of these two high throughput devices for use in sodium channel inhibitor drug discovery programs. Overall, the PatchXpressTM and IonWorksTM electrophysiology platforms have individual strengths that make them complementary to each other. Both platforms are capable of measuring state dependent modulation of sodium channels. IonWorksTM has the throughput to allow for effective screening of libraries of tens of thousands of compounds whereas the PatchXpressTM has more flexibility to provide quantitative voltage clamp, which is useful in structure activity evaluations for the hit-to-lead and lead optimization stages of sodium channel drug discovery.

A prerequisite for a successful target-based drug discovery program is a robust data set that increases confidence in the validation of the molecular target and the therapeutic approach. Given the significant time and resource investment required to carry a drug to market, early selection of targets that can be modulated safely and effectively forms the basis for a strong portfolio and pipeline. In this article we present some of the more useful scientific approaches that can be applied toward the validation of ion channel targets, a molecular family with a history of clinical success in therapeutic areas such as cardiovascular, respiratory, pain and neuroscience.

1-Deoxy-D-xylulose 5-phosphate reductoisomerase (Dxr) is a key enzyme in a biosynthetic pathway for isoprenoids that is unique to eubacteria and plants. Dxr catalyzes the rearrangement and NADPH-dependent reduction of 1-deoxy-D-xylulose 5-phosphate to 2-C-methyl-D-erythritol 4-phosphate. The authors have purified Escherichia coli Dxr and devised a high-throughput screen (HTS) for compounds that bind to this enzyme at a functional site. Evidence is presented that the surrogate ligand directly binds or allosterically affects both the D-1-deoxyxylulose 5-phosphate (DXP) and NADPH binding sites. Compounds that bind at either or both sites that compete for binding with the surrogate ligand register as hits. The time-resolved fluorescence-based assay represents an improvement over the Dxr enzyme assay that relies on relatively insensitive measurements of NADPH oxidation. Screening 32,000 compounds from a diverse historical library, the authors obtained 89 potent inhibitors in the surrogate ligand competition assay. The results presented here suggest that peptide surrogate ligands may be useful in formatting HTS for proteins with difficult biochemical assays or targets of unknown function.

Actualmente las redes 802.11 se han convertido en la primera opción para el acceso inalámbrico a la Internet. Para conectarse, un dispositivo cualquiera se registra a algún Punto de Acceso pasando primero por un costoso proceso de búsqueda de los APs disponibles. El estándar IEEE 802.11 deja abierta la posibilidad de implementar los criterios de búsqueda estableciendo solamente los mensajes necesarios para tal efecto. En este artículo caracterizamos distintos dispositivos a través de un sistema especialmente construido para tal fin. El sistema propuesto es capaz de escuchar todos los canales de manera simultanea para así mostrar verazmente las estrategias que siguen distintos dispositivos durante el proceso de búsqueda. El sistema propuesto permite movilidad, operación bajo estándares abiertos y uso de componentes de bajo costo. aaraujo@cenditel.gob.ve andres.arcia@ula.ve

9 p. SAFET es un sistema que está conformado por un analizador de lenguaje XML/DTD y un conjunto de aplicaciones, todo ello integrado con tecnologías de firma electrónica y estampillado de tiempo. En este sentido, se propone la vinculación natural del concepto de flujo de trabajo con los procesos de firma electrónica y posteriormente el de estampillado de tiempo, lo que aporta nuevos elementos en la consolidación de un patrón para la construcción de este tipo de aplicaciones. Bajo este enfoque la firma electrónica no se muestra como una sustitución completa de la firma manuscrita, sino como un elemento tecnológico de la era digital con carácter jurídico que es complementario, y que permite realizar operaciones que resultarían difíciles o imposibles de ejecutar de forma segura con elementos no digitales. SAFET genera grafos y reportes en diferentes formatos de archivo. En la última sección se presenta una aplicación con firma electrónica generada utilizando el sistema. SAFET is a system that consists of a language parser XML/DTD and applications integrated with electronic signature technology. We propose the natural linkage of the workflow concept with electronic signature concept, which adds new elements in the consolidation of a pattern for develop such applications. Under this approach the electronic signature is not a complete replacement of handwritten signature, it's a technological element of the digital age with legal basis, complementary, and allows operations that would be difficult or impossible to run safely with non-digital terms. SAFET generates graphs and reports using different file formats. The final section presents a software application with electronic signature generated using the system. Bucaramanga

A series of N-pyridyl benzamide KCNQ2/Q3 potassium channel openers were identified and found to be active in animal models of epilepsy and pain. The best compound 12 [ICA-027243, N-(6-chloro-pyridin-3-yl)-3,4-difluoro-benzamide] has an EC50 of 0.38 μM and is selective for KCNQ2/Q3 channels. This compound was active in several rodent models of epilepsy and pain but upon repeated dosing had a number of unacceptable toxicities that prevented further development. On the basis of the structure−activity relationships developed around 12, a second compound, 51, [N-(2-chloro-pyrimidin-5-yl)-3,4-difluoro-benzamide, ICA-069673], was prepared and advanced into a phase 1 clinical study. Herein, we describe the structure−activity relationships that led to the identification of compound 12 and to the corresponding pyrimidine 51.