RESUMEN
Leishmaniasis is a group of neglected tropical diseases caused by at least 20 species of Leishmania protozoa, which are spread by the bite of infected sandflies. There are three main forms of the disease: cutaneous leishmaniasis (CL, the most common), visceral leishmaniasis (VL, also known as kala-azar, the most serious), and mucocutaneous leishmaniasis. One billion people live in areas endemic to leishmaniasis, with an annual estimation of 30,000 new cases of VL and more than 1 million of CL. New treatments for leishmaniasis are an urgent need, as the existing ones are inefficient, toxic, and/or expensive. We have revised the experimental structure-based drug design (SBDD) efforts applied to the discovery of new drugs against leishmaniasis. We have grouped the explored targets according to the metabolic pathways they belong to, and the key achieved advances are highlighted and evaluated. In most cases, SBDD studies follow high-throughput screening campaigns and are secondary to pharmacokinetic optimization, due to the majoritarian belief that there are few validated targets for SBDD in leishmaniasis. However, some SBDD strategies have significantly contributed to new drug candidates against leishmaniasis and a bigger number holds promise for future development.
Asunto(s)
Leishmania , Leishmaniasis Cutánea , Leishmaniasis Visceral , Humanos , Leishmaniasis Visceral/tratamiento farmacológico , Leishmaniasis Visceral/complicaciones , Leishmaniasis Visceral/epidemiología , Leishmaniasis Cutánea/tratamiento farmacológico , Leishmaniasis Cutánea/complicaciones , Leishmaniasis Cutánea/epidemiología , Ensayos Analíticos de Alto RendimientoRESUMEN
The low aqueous solubility of colchicine site antimitotic agents, of which the trimethoxyphenyl (A ring) is a heavy contributor, is a serious drawback in their clinical development. We have designed new A ring analogs with chameleonic masked polar amino groups able to increase aqueous solubility and also behave as non-polar through intramolecular hydrogen bonds when bound to tubulin. We have incorporated these new A rings in several scaffolds (sulfonamides, combretastatins, phenstatins, isocombretastatins), synthesized, and assayed 43 representatives. The amino analogs show improved aqueous solubility and some of them (8, 60Z, and 67) nanomolar anti-proliferative potencies against human cancer cell lines, with the most favorable substituent being a 3-methylamino group. The antiproliferative effect relates to tubulin inhibition as shown by in vitro tubulin polymerization inhibition, immunofluorescence microscopy, and cell cycle and apoptosis analysis by flow cytometry. The compounds arrest the cell cycle of treated cells in G2/M and later develop an apoptotic response. Docking studies suggested binding at the colchicine site of tubulin with good agreement with the DFT models of the new structural variations made. The 3-methylamino-4,5dimethoxyphenyl moiety is an example of the masked polar group incorporation (MPGI) strategy for soluble ligands binding to hydrophobic sites and a good trimethoxyphenyl ring replacement for the development of new colchicine site ligands.
Asunto(s)
Antineoplásicos , Colchicina , Humanos , Colchicina/química , Línea Celular Tumoral , Sitios de Unión , Tubulina (Proteína)/metabolismo , Solubilidad , Relación Estructura-Actividad , Moduladores de Tubulina/farmacología , Moduladores de Tubulina/química , Antineoplásicos/farmacología , Antineoplásicos/química , Proliferación CelularRESUMEN
Heart diseases rank among the most fatal health concerns globally, with the majority being preventable through early diagnosis and effective treatment. Electrocardiogram (ECG) analysis is critical in detecting heart diseases, as it captures the heart's electrical activities. For continuous monitoring, wearable electrocardiographic devices must ensure user comfort over extended periods, typically 24 to 48 h. These devices demand specialized algorithms with low computational complexity to accommodate memory and power consumption constraints. One of the most crucial aspects of ECG signals is accurately detecting heartbeat intervals, specifically the R peaks. In this study, we introduce a novel algorithm designed for wearable devices, offering two primary attributes: robustness against noise and low computational complexity. Our algorithm entails fitting a least-squares parabola to the ECG signal and adaptively shaping it as it sweeps through the signal. Notably, our proposed algorithm eliminates the need for band-pass filters, which can inadvertently smooth the R peaks, making them more challenging to identify. We compared the algorithm's performance using two extensive databases: the meta-database QT database and the BIH-MIT database. Importantly, our method does not necessitate the precise localization of the ECG signal's isoelectric line, contributing to its low computational complexity. In the analysis of the QT database, our algorithm demonstrated a substantial advantage over the classical Pan-Tompkins algorithm and maintained competitiveness with state-of-the-art approaches. In the case of the BIH-MIT database, the performance results were more conservative; they continued to underscore the real-world utility of our algorithm in clinical contexts.
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Cardiopatías , Dispositivos Electrónicos Vestibles , Humanos , Procesamiento de Señales Asistido por Computador , Electrocardiografía/métodos , AlgoritmosRESUMEN
Increasing awareness of the structure of microtubules has made tubulin a relevant target for the research of novel chemotherapies. Furthermore, the particularly high sensitivity of glioblastoma multiforme (GBM) cells to microtubule disruption could open new doors in the search for new anti-GBM treatments. However, the difficulties in developing potent anti-tubulin drugs endowed with improved pharmacokinetic properties necessitates the expansion of medicinal chemistry campaigns. The application of an ensemble pharmacophore screening methodology helped to optimize this process, leading to the development of a new tetrazole-based tubulin inhibitor. Considering this scaffold, we have synthesized a new family of tetrazole derivatives that achieved remarkable antimitotic effects against a broad panel of cancer cells, especially against GBM cells, showing high selectivity in comparison with non-tumor cells. The compounds also exerted high aqueous solubility and were demonstrated to not be substrates of efflux pumps, thus overcoming the main limitations that are usually associated with tubulin binding agents. Tubulin polymerization assays, immunofluorescence experiments, and flow cytometry studies demonstrated that the compounds target tubulin and arrest cells at the G2/M phase followed by induction of apoptosis. The docking experiments agreed with the proposed interactions at the colchicine site and explained the structure-activity relationships.
Asunto(s)
Antineoplásicos , Glioblastoma , Humanos , Tubulina (Proteína)/metabolismo , Glioblastoma/tratamiento farmacológico , Antineoplásicos/uso terapéutico , Ensayos de Selección de Medicamentos Antitumorales , Proliferación Celular , Relación Estructura-Actividad , Moduladores de Tubulina/química , Colchicina/farmacología , Línea Celular Tumoral , Tetrazoles/farmacología , Estructura Molecular , Simulación del Acoplamiento MolecularRESUMEN
Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. AMD is characterized by the formation of lipidic deposits between the retinal pigment epithelium (RPE) and the choroid called drusen. 7-Ketocholesterol (7KCh), an oxidized-cholesterol derivative, is closely related to AMD as it is one of the main molecules accumulated in drusen. 7KCh induces inflammatory and cytotoxic responses in different cell types, and a better knowledge of the signaling pathways involved in its response would provide a new perspective on the molecular mechanisms that lead to the development of AMD. Furthermore, currently used therapies for AMD are not efficient enough. Sterculic acid (SA) attenuates the 7KCh response in RPE cells and is presented as an alternative to improve these therapies. By using genome-wide transcriptomic analysis in monkey RPE cells, we have provided new insight into 7KCh-induced signaling in RPE cells, as well as the protective capacity of SA. 7KCh modulates the expression of several genes associated with lipid metabolism, endoplasmic reticulum stress, inflammation and cell death and induces a complex response in RPE cells. The addition of SA successfully attenuates the deleterious effect of 7KCh and highlights its potential for the treatment of AMD.
Asunto(s)
Degeneración Macular , Transcriptoma , Humanos , Cetocolesteroles/farmacología , Epitelio Pigmentado de la Retina/metabolismo , Degeneración Macular/metabolismo , Epitelio/metabolismoRESUMEN
Antimitotic agents are one of the more successful types of anticancer drugs, but they suffer from toxicity and resistance. The application of approved drugs to new indications (i.e., drug repurposing) is a promising strategy for the development of new drugs. It relies on finding pattern similarities: drug effects to other drugs or conditions, similar toxicities, or structural similarity. Here, we recursively searched a database of approved drugs for structural similarity to several antimitotic agents binding to a specific site of tubulin, with the expectation of finding structures that could fit in it. These searches repeatedly retrieved frentizole, an approved nontoxic anti-inflammatory drug, thus indicating that it might behave as an antimitotic drug devoid of the undesired toxic effects. We also show that the usual repurposing approach to searching for targets of frentizole failed in most cases to find such a relationship. We synthesized frentizole and a series of analogs to assay them as antimitotic agents and found antiproliferative activity against HeLa tumor cells, inhibition of microtubule formation within cells, and arrest at the G2/M phases of the cell cycle, phenotypes that agree with binding to tubulin as the mechanism of action. The docking studies suggest binding at the colchicine site in different modes. These results support the repurposing of frentizole for cancer treatment, especially for glioblastoma.
Asunto(s)
Antimitóticos , Antineoplásicos , Antimitóticos/farmacología , Tubulina (Proteína)/metabolismo , Línea Celular Tumoral , Relación Estructura-Actividad , Colchicina/química , Antineoplásicos/farmacología , Antineoplásicos/química , Moduladores de Tubulina/química , Ensayos de Selección de Medicamentos Antitumorales , Proliferación Celular , Sitios de UniónRESUMEN
In this paper, we addressed the problem of dataset scarcity for the task of network intrusion detection. Our main contribution was to develop a framework that provides a complete process for generating network traffic datasets based on the aggregation of real network traces. In addition, we proposed a set of tools for attribute extraction and labeling of traffic sessions. A new dataset with botnet network traffic was generated by the framework to assess our proposed method with machine learning algorithms suitable for unbalanced data. The performance of the classifiers was evaluated in terms of macro-averages of F1-score (0.97) and the Matthews Correlation Coefficient (0.94), showing a good overall performance average.
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Algoritmos , Aprendizaje Automático , Proyectos de InvestigaciónRESUMEN
Ovarian cancer (OC) is one of the most common gynecologic neoplasia and has the highest mortality rate, which is mainly due to late-stage diagnosis and chemotherapy resistance. There is an urgent need to explore new and better therapeutic strategies. We have previously described a family of Microtubule Destabilizing Sulfonamides (MDS) that does not trigger multidrug-mediated resistance in OC cell lines. MDS bind to the colchicine site of tubulin, disrupting the microtubule network and causing antiproliferative and cytotoxic effects. In this work, a novel microtubule-destabilizing agent (PILA9) was synthetized and characterized. This compound also inhibited OC cell proliferation and induced G2/M cell cycle arrest and apoptosis. Interestingly, PILA9 was significantly more cytotoxic than MDS. Here, we also analyzed the effect of these microtubule-destabilizing agents (MDA) in combination with Panobinostat, a pan-histone deacetylase inhibitor. We found that Panobinostat synergistically enhanced MDA-cytotoxicity. Mechanistically, we observed that Panobinostat and MDA induced α-tubulin acetylation and that the combination of both agents enhanced this effect, which could be related to the observed synergy. Altogether, our results suggest that MDA/Panobinostat combinations could represent new therapeutic strategies against OC.
Asunto(s)
Antineoplásicos , Neoplasias Ováricas , Femenino , Humanos , Panobinostat/farmacología , Ácidos Hidroxámicos/farmacología , Indoles/farmacología , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/uso terapéutico , Antineoplásicos/farmacología , Apoptosis , Proliferación Celular , Microtúbulos , Sulfonamidas/farmacología , Neoplasias Ováricas/tratamiento farmacológico , Línea Celular TumoralRESUMEN
Searching for improved indolesulfonamides with higher polarities, 45 new analogues with modifications on the sulfonamide nitrogen, the methoxyaniline, and/or the indole 3-position were synthesised. They show submicromolar to nanomolar antiproliferative IC50 values against four human tumour cell lines and they are not P-glycoprotein substrates as their potencies against HeLa cells did not improve upon cotreatment with multidrug resistance (MDR) inhibitors. The compounds inhibit tubulin polymerisation in vitro and in cells, thus causing a mitotic arrest followed by apoptosis as shown by cell cycle distribution studies. Molecular modelling studies indicate binding at the colchicine site. Methylated sulfonamides were more potent than those with large and polar substitutions. Amide, formyl, or nitrile groups at the indole 3-position provided drug-like properties for reduced toxicity, with Polar Surface Areas (PSA) above a desirable 75 Å2. Nitriles 15 and 16 are potent polar analogues and represent an interesting class of new antimitotics.
Asunto(s)
Antineoplásicos/farmacología , Colchicina/antagonistas & inhibidores , Sulfonamidas/farmacología , Moduladores de Tubulina/farmacología , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntesis química , Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Colchicina/química , Colchicina/metabolismo , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Células HeLa , Humanos , Modelos Moleculares , Estructura Molecular , Polimerizacion/efectos de los fármacos , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Sulfonamidas/química , Tubulina (Proteína)/química , Moduladores de Tubulina/síntesis química , Moduladores de Tubulina/química , Células Tumorales CultivadasRESUMEN
Thirty seven N-(5-methoxyphenyl)-4-methoxybenzenesulphonamide with methoxy or/and bromo substitutions (series 1-4) and with different substituents on the sulphonamide nitrogen have been synthesised. 21 showed sub-micromolar cytotoxicity against HeLa and HT-29 human tumour cell lines, and were particularly effective against MCF7. The most potent series has 2,5-dimethoxyanilines, especially the 4-brominated compounds 23-25. The active compounds inhibit microtubular protein polymerisation at micromolar concentrations, thus pointing at tubulin as the target. Co-treatment with the MDR inhibitor verapamil suggests that they are not MDR substrates. Compound 25 showed nanomolar antiproliferative potency. It severely disrupts the microtubule network in cells and arrests cells at the G2/M cell-cycle phase, thus confirming tubulin targeting. 25 triggered apoptotic cell death, and induced autophagy. Docking studies suggest binding in a distinct way to the colchicine site. These compounds are promising new antitumor agents acting on tubulin.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Antineoplásicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Sulfonamidas/uso terapéutico , Adenocarcinoma/patología , Neoplasias de la Mama/patología , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Células MCF-7RESUMEN
Pan-Gyn cancers entail 1 in 5 cancer cases worldwide, breast cancer being the most commonly diagnosed and responsible for most cancer deaths in women. The high incidence and mortality of these malignancies, together with the handicaps of taxanes-first-line treatments-turn the development of alternative therapeutics into an urgency. Taxanes exhibit low water solubility that require formulations that involve side effects. These drugs are often associated with dose-limiting toxicities and with the appearance of multi-drug resistance (MDR). Here, we propose targeting tubulin with compounds directed to the colchicine site, as their smaller size offer pharmacokinetic advantages and make them less prone to MDR efflux. We have prepared 52 new Microtubule Destabilizing Sulfonamides (MDS) that mostly avoid MDR-mediated resistance and with improved aqueous solubility. The most potent compounds, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methylaminobenzenesulfonamide 38, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 42, and N-benzyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 45 show nanomolar antiproliferative potencies against ovarian, breast, and cervix carcinoma cells, similar or even better than paclitaxel. Compounds behave as tubulin-binding agents, causing an evident disruption of the microtubule network, in vitro Tubulin Polymerization Inhibition (TPI), and mitotic catastrophe followed by apoptosis. Our results suggest that these novel MDS may be promising alternatives to taxane-based chemotherapy in chemoresistant Pan-Gyn cancers.
Asunto(s)
Antineoplásicos/farmacología , Sulfonamidas/farmacología , Taxoides/farmacología , Moduladores de Tubulina/farmacología , Tubulina (Proteína)/metabolismo , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Femenino , Células HT29 , Células HeLa , Humanos , Células MCF-7 , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Polimerizacion/efectos de los fármacos , Sulfonamidas/química , Sulfonamidas/uso terapéutico , Taxoides/uso terapéutico , Moduladores de Tubulina/química , Moduladores de Tubulina/uso terapéuticoRESUMEN
Apolipoprotein D (Apo D) overexpression is a general finding across neurodegenerative conditions so the role of this apolipoprotein in various neuropathologies such as multiple sclerosis (MS) has aroused a great interest in last years. However, its mode of action, as a promising compound for the development of neuroprotective drugs, is unknown. The aim of this work was to address the potential of Apo D to prevent the action of cuprizone (CPZ), a toxin widely used for developing MS models, in oligodendroglial and neuroblastoma cell lines. On one hand, immunocytochemical quantifications and gene expression measures showed that CPZ compromised neural mitochondrial metabolism but did not induce the expression of Apo D, except in extremely high doses in neurons. On the other hand, assays of neuroprotection demonstrated that antipsychotic drug, clozapine, induced an increase in Apo D synthesis only in the presence of CPZ, at the same time that prevented the loss of viability caused by the toxin. The effect of the exogenous addition of human Apo D, once internalized, was also able to directly revert the loss of cell viability caused by treatment with CPZ by a reactive oxygen species (ROS)-independent mechanism of action. Taken together, our results suggest that increasing Apo D levels, in an endo- or exogenous way, moderately prevents the neurotoxic effect of CPZ in a cell model that seems to replicate some features of MS which would open new avenues in the development of interventions to afford MS-related neuroprotection.
Asunto(s)
Apolipoproteínas D/genética , Enfermedades Desmielinizantes/genética , Esclerosis Múltiple/genética , Oligodendroglía/metabolismo , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cuprizona/toxicidad , Enfermedades Desmielinizantes/patología , Enfermedades Desmielinizantes/terapia , Modelos Animales de Enfermedad , Humanos , Ratones , Esclerosis Múltiple/patología , Esclerosis Múltiple/terapia , Fármacos Neuroprotectores/uso terapéutico , Oligodendroglía/efectos de los fármacos , Oligodendroglía/patología , Especies Reactivas de Oxígeno/metabolismoRESUMEN
IMP dehydrogenase (IMPDH) is an essential enzyme that catalyzes the rate-limiting step in the de novo guanine nucleotide biosynthetic pathway. Because of its involvement in the control of cell division and proliferation, IMPDH represents a therapeutic for managing several diseases, including microbial infections and cancer. IMPDH must be tightly regulated, but the molecular mechanisms responsible for its physiological regulation remain unknown. To this end, we recently reported an important role of adenine and guanine mononucleotides that bind to the regulatory Bateman domain to allosterically modulate the catalytic activity of eukaryotic IMPDHs. Here, we have used enzyme kinetics, X-ray crystallography, and small-angle X-ray scattering (SAXS) methodologies to demonstrate that adenine/guanine dinucleoside polyphosphates bind to the Bateman domain of IMPDH from the fungus Ashbya gossypii with submicromolar affinities. We found that these dinucleoside polyphosphates modulate the catalytic activity of IMPDHs in vitro by efficiently competing with the adenine/guanine mononucleotides for the allosteric sites. These results suggest that dinucleoside polyphosphates play important physiological roles in the allosteric regulation of IMPDHs by adding an additional mechanism for fine-tuning the activities of these enzymes. We propose that these findings may have important implications for the design of therapeutic strategies to inhibit IMPDHs.
Asunto(s)
Fosfatos de Dinucleósidos/química , IMP Deshidrogenasa/química , Conformación Proteica , Dominios Proteicos/genética , Regulación Alostérica/genética , Infecciones Bacterianas/genética , Infecciones Bacterianas/microbiología , Sitios de Unión/genética , Catálisis , Cristalografía por Rayos X , Fosfatos de Dinucleósidos/genética , Eremothecium/genética , Nucleótidos de Guanina , Humanos , IMP Deshidrogenasa/genética , IMP Deshidrogenasa/ultraestructura , Modelos Moleculares , Neoplasias/genética , Dispersión del Ángulo Pequeño , Difracción de Rayos XRESUMEN
Colchicine site antimitotic agents typically suffer from low aqueous solubilities and are formulated as phosphate prodrugs of phenolic groups. These hydroxyl groups are the aim of metabolic transformations leading to resistance. There is an urgent need for more intrinsically soluble analogues lacking these hydroxyl groups. The 3,4,5-trimethoxyphenyl ring of combretastatin A-4 is a liability in terms of solubility but it is considered essential for high cytotoxic and tubulin polymerization inhibitory (TPI) activity. We have synthesized 36 new analogues of combretastatin A-4 replacing the trimethoxyphenyl moiety with more polar pyridine based moieties, measured their aqueous solubility, and studied their anti-proliferative effects against 3 human cancer cell lines. We show here that pyridine rings can be successful replacements for the trimethoxyphenyl ring, resulting in potent and more soluble analogues. The more straightforward replacement, a 2,6-dimethoxypyridine ring led to inactive analogues, but a 2-methoxy-6-methylsulfanylpyridine moiety led to active analogues when combined with different B rings. This replacement led to potent cytotoxic activity against sensitive human cancer cell lines due to tubulin inhibition, as shown by cell cycle analysis, confocal microscopy, and tubulin polymerization inhibitory activity studies. Cell cycle analysis also showed apoptotic responses following treatment. Docking studies suggested binding at the colchicine site of tubulin and provided a good agreement with the observed SAR. A 2-methoxy-6-methylsulfanylpyridine moiety is a good trimethoxyphenyl ring replacement for the development of new colchicine site ligands.
Asunto(s)
Antineoplásicos/farmacología , Colchicina/farmacología , Piridinas/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Colchicina/síntesis química , Colchicina/química , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ligandos , Estructura Molecular , Polimerizacion/efectos de los fármacos , Piridinas/química , Solubilidad , Relación Estructura-Actividad , Tubulina (Proteína)/metabolismo , Células Tumorales CultivadasRESUMEN
Tubulin, the microtubules and their dynamic behavior are amongst the most successful antitumor, antifungal, antiparasitic, and herbicidal drug targets. Sulfonamides are exemplary drugs with applications in the clinic, in veterinary and in the agrochemical industry. This review summarizes the actual state and recent progress of both fields looking from the double point of view of the target and its drugs, with special focus onto the structural aspects. The article starts with a brief description of tubulin structure and its dynamic assembly and disassembly into microtubules and other polymers. Posttranslational modifications and the many cellular means of regulating and modulating tubulin's biology are briefly presented in the tubulin code. Next, the structurally characterized drug binding sites, their occupying drugs and the effects they induce are described, emphasizing on the structural requirements for high potency, selectivity, and low toxicity. The second part starts with a summary of the favorable and highly tunable combination of physical-chemical and biological properties that render sulfonamides a prototypical example of privileged scaffolds with representatives in many therapeutic areas. A complete description of tubulin-binding sulfonamides is provided, covering the different species and drug sites. Some of the antimitotic sulfonamides have met with very successful applications and others less so, thus illustrating the advances, limitations, and future perspectives of the field. All of them combine in a mechanism of action and a clinical outcome that conform efficient drugs.
Asunto(s)
Sulfonamidas/farmacología , Moduladores de Tubulina/farmacología , Secuencia de Aminoácidos , Animales , Ensayos Clínicos como Asunto , Humanos , Sulfonamidas/química , Andamios del Tejido/química , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/químicaRESUMEN
This review will focus on the inflammatory and toxic mechanism of action of 7-ketocholesterol (7KCh) and the potential implications of its accumulation, especially in the retina. 7KCh is a pro-inflammatory oxysterol usually associated with oxidized lipoprotein deposits present in aged retinas. High amounts of 7KCh can be generated in situ in these lipoprotein deposits possibly through a free radical-mediated mechanism catalyzed by iron. 7KCh seems to activate several kinase signaling pathways that work via multiple transcription factors to induce cytokines and intracellular effectors causing cell death. There seems to be a controversy in the literature in relation to the mechanisms of death induced by 7KCh. Some of the discrepancies arise from the way the oxysterol is delivered because different signaling pathways are activated in different experimental setups. The elucidation of the inflammatory and toxic mechanisms is crucial for the discovery and design of new therapies. Importantly, there is little evidence of 7KCh detoxifying mechanisms in the retina, although some potential enzymes have been described. Thus, continuous formation throughout life and potential toxicity of 7KCh points it out as an "age-related" risk factor in pathologies such as age-related macular degeneration.
Asunto(s)
Inhibidores Enzimáticos/toxicidad , Cetocolesteroles/toxicidad , Degeneración Macular/inducido químicamente , Retina/efectos de los fármacos , Retinitis/inducido químicamente , Animales , Muerte Celular , Humanos , Inflamación , Degeneración Macular/patología , Oxidación-Reducción , Epitelio Pigmentado de la Retina/efectos de los fármacos , Epitelio Pigmentado de la Retina/patología , Retinitis/patologíaRESUMEN
The monitoring and processing of electrocardiogram (ECG) beats have been actively studied in recent years: new lines of research have even been developed to analyze ECG signals using mobile devices. Considering these trends, we proposed a simple and low computing cost algorithm to process and analyze an ECG signal. Our approach is based on the use of linear regression to segment the signal, with the goal of detecting the R point of the ECG wave and later, to separate the signal in periods for detecting P, Q, S, and T peaks. After pre-processing of ECG signal to reduce the noise, the algorithm was able to efficiently detect fiducial points, information that is transcendental for diagnosis of heart conditions using machine learning classifiers. When tested on 260 ECG records, the detection approach performed with a Sensitivity of 97.5% for Q-point and 100% for the rest of ECG peaks. Finally, we validated the robustness of our algorithm by developing an ECG sensor to register and transmit the acquired signals to a mobile device in real time.
Asunto(s)
Electrocardiografía/métodos , Corazón/fisiología , Algoritmos , Corazón/diagnóstico por imagen , Humanos , Modelos Lineales , Procesamiento de Señales Asistido por ComputadorRESUMEN
With the rapid deployment of the Internet of Things and cloud computing, it is necessary to enhance authentication protocols to reduce attacks and security vulnerabilities which affect the correct performance of applications. In 2019 a new lightweight IoT-based authentication scheme in cloud computing circumstances was proposed. According to the authors, their protocol is secure and resists very well-known attacks. However, when we evaluated the protocol we found some security vulnerabilities and drawbacks, making the scheme insecure. Therefore, we propose a new version considering login, mutual authentication and key agreement phases to enhance the security. Moreover, we include a sub-phase called evidence of connection attempt which provides proof about the participation of the user and the server. The new scheme achieves the security requirements and resists very well-known attacks, improving previous works. In addition, the performance evaluation demonstrates that the new scheme requires less communication-cost than previous authentication protocols during the registration and login phases.
RESUMEN
We carried out surveys on the use of Cordia nodosa Lam. in the jungles of Bobonaza (Ecuador). We documented this knowledge to prevent its loss under the Framework of the Convention on Biological Diversity and the Nagoya Protocol. We conducted bibliographic research and identified quercetrin as a significant bioactive molecule. We studied its in silico biological activity. The selected methodology was virtual docking experiments with the proteins responsible for the venomous action of snakes. The molecular structures of quercetrin and 21 selected toxins underwent corresponding tests with SwissDock and Chimera software. The results point to support its antiophidic use. They show reasonable geometries and a binding free energy of -7 to -10.03 kcal/mol. The most favorable values were obtained for the venom of the Asian snake Naja atra (5Z2G, -10.03 kcal/mol). Good results were also obtained from the venom of the Latin American Bothrops pirajai (3CYL, -9.71 kcal/mol) and that of Ecuadorian Bothrops asper snakes (5TFV, -9.47 kcal/mol) and Bothrops atrox (5TS5, -9.49 kcal/mol). In the 5Z2G and 5TS5 L-amino acid oxidases, quercetrin binds in a pocket adjacent to the FAD cofactor, while in the myotoxic homologues of PLA2, 3CYL and 5TFV, it joins in the hydrophobic channel formed when oligomerizing, in the first one similar to α-tocopherol. This study presents a case demonstration of the potential of bioinformatic tools in the validation process of ethnobotanical phytopharmaceuticals and how in silico methods are becoming increasingly useful for sustainable drug discovery.
Asunto(s)
Antídotos/química , Antídotos/farmacología , Cordia/química , Modelos Moleculares , Extractos Vegetales/química , Extractos Vegetales/farmacología , Sitios de Unión , Conformación Molecular , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Estructura Molecular , Unión Proteica , Venenos de Serpiente/antagonistas & inhibidores , Venenos de Serpiente/química , Relación Estructura-Actividad , Toxinas Biológicas/antagonistas & inhibidores , Toxinas Biológicas/química , ÁrbolesRESUMEN
Colchicine site ligands suffer from low aqueous solubility due to the highly hydrophobic nature of the binding site. A new strategy for increasing molecular polarity without exposing polar groups-termed masked polar group incorporation (MPGI)-was devised and applied to nitrogenated combretastatin analogues. Bulky ortho substituents to the pyridine nitrogen hinder it from the hydrophobic pocket while increasing molecular polarity. The resulting analogues show improved aqueous solubilities and highly potent antiproliferative activity against several cancer cell lines of different origin. The more potent compounds showed moderate tubulin polymerization inhibitory activity, arrested the cell cycle of treated cells at the G2/M phase, and subsequently caused apoptotic cell death represented by the cells gathered at the subG0/G1 population after 48 h of treatment. Annexin V/Propidium Iodide (PI) double-positive cells observed after 72 h confirmed the induction of apoptosis. Docking studies suggest binding at the colchicine site of tubulin in a similar way as combretastatin A4, with the polar groups masked by the vicinal substituents. These results validate the proposed strategy for the design of colchicine site ligands and open a new road to increasing the aqueous solubility of ligands binding in apolar environments.