123 research outputs found

    Systems-Based Design of Bi-Ligand Inhibitors of Oxidoreductases: Filling the Chemical Proteomic Toolbox

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    Genomics-driven growth in the number of enzymes of unknown function has created a need for better strategies to characterize them. Since enzyme inhibitors have traditionally served this purpose, we present here an efficient systems-based inhibitor design strategy, enabled by bioinformatic and NMR structural developments. First, we parse the oxidoreductase gene family into structural subfamilies termed pharmacofamilies, which share pharmacophore features in their cofactor binding sites. Then we identify a ligand for this site and use NMR-based binding site mapping (NMR SOLVE) to determine where to extend a combinatorial library, such that diversity elements are directed into the adjacent substrate site. The cofactor mimic is reused in the library in a manner that parallels the reuse of cofactor domains in the oxidoreductase gene family. A library designed in this manner yielded specific inhibitors for multiple oxidoreductases

    Deletion of Cdc42 Enhances ADAM17-Mediated Vascular Endothelial Growth Factor Receptor 2 Shedding and Impairs Vascular Endothelial Cell Survival and Vasculogenesis

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    Cdc42 is a Ras-related GTPase that plays an important role in the regulation of a range of cellular functions, including cell migration, proliferation, and survival. Consistent with its critical functions in vitro, the inactivation of Cdc42 in mice has been shown to result in embryonic lethality at embryonic day 6.5 (E6.5) before blood vessel formation. To determine the role of Cdc42 in new blood vessel formation, we have generated vascular endothelial cell (EC)-specific Cdc42 knockout mice by crossing Cdc42(flox/flox) mice with Tie2-Cre mice. The deletion of Cdc42 in ECs caused embryonic lethality with vasculogenesis and angiogenesis defects. We observed that Cdc42 is critical for EC migration and survival but not for cell cycle progression. Moreover, we found that the inactivation of Cdc42 in ECs decreased the level of vascular endothelial growth factor receptor 2 (VEGFR2) protein on the EC surface and promoted the production of a 75-kDa membrane-associated C-terminal VEGFR2 fragment. Using cultured primary mouse ECs and human umbilical vein ECs, we have demonstrated that the deletion of Cdc42 increased ADAM17-mediated VEGFR2 shedding. Notably, inhibition of ADAM17 or overexpression of VEGFR2 can partially reverse Cdc42 deletion-induced EC apoptosis. These data indicate that Cdc42 is essential for VEGFR2-mediated signal transduction in blood vessel formation

    Effects of canagliflozin on body weight and relationship to HbA1c and blood pressure changes in patients with type 2 diabetes

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    De manera general, la apendicitis aguda es la causa de abdomen agudo más frecuente en la edad pediátrica, representa el 10% de todas las admisiones a los diferentes servicios de urgencias; sin embargo, en los niños menores de dos años su presentación es infrecuente, alrededor del 2% de todos los casos de abdomen agudo. Se presenta un caso clínico que corresponde a una paciente de 13 días de vida que fue llevada al servicio de emergencia por presentar vómitos de tipo bilioso. Fue intervenida quirúrgicamente con diagnóstico preoperatorio de atresia intestinal, posterior a la cirugía el diagnóstico definitivo correspondió a apendicitis y peritonitis por perforación apendicular. Se explora y se encuentra como hallazgo quirúrgico: obstrucción íleon terminal con una banda adherida al ciego, apéndice cecal perforada, peritonitis localizada. La apendicitis neonatal puede presentarse en otras patologías como la enfermedad de Hirschsprung, la enterocolitis necrosante, el íleo o el tapón meconial, entre otras. La apendicitis se presenta como un cuadro clínico inespecífico, su diagnóstico se lo realiza como un hallazgo transoperatorio lo que eleva la mortalidad.

    Rationale, design and baseline characteristics of the CANagliflozin cardioVascular Assessment Study-Renal (CANVAS-R):A randomized, placebo-controlled trial

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    Aims: The primary aim of the CANagliflozin cardioVascular Assessment Study-Renal (CANVAS-R) is to determine whether the favourable effects of inhibition of the sodium glucose co-transporter 2 (SGLT2) on blood glucose, blood pressure and body weight are accompanied by protection against adverse renal outcomes. Materials and methods: CANVAS-R is a prospective, randomized, double-blind, placebo-controlled trial in patients with type 2 diabetes with a history or high risk of cardiovascular events. Patients were randomly assigned to once-daily placebo or canagliflozin 100 mg (with optional uptitration to 300 mg) for a planned average of 2.5 years of follow-up. The primary outcome is kidney disease progression, defined by class change in albuminuria. The two secondary outcomes are the composite of hospitalized heart failure or cardiovascular death, and cardiovascular death alone. Effects on end-stage renal disease and a range of other outcomes will also be explored. Results: A total of 5812 participants were recruited at 422 sites in 24 countries between January 2014 and May 2015. The mean baseline age was 64 years, mean duration of diabetes was 14 years, mean glycated haemoglobin level was 8.3% and mean body mass index was 32 kg/m(2). Of these participants, 37% were women, 71% had a history of cardiovascular disease, 22.3% had microalbuminuria and 8.7% had macroalbuminuria. The mean baseline estimated glomerular filtration rate was 76 mL/min/1.73 m(2). The study will have at least 90% power (P =.05) to detect a 22% or greater reduction in the risk of progression of albuminuria. Conclusions: The trial should define the potential renoprotective effect of canagliflozin and will provide additional important new data about its effects on vascular outcomes, death and kidney failure

    Muscle cells of sporadic amyotrophic lateral sclerosis patients secrete neurotoxic vesicles

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    Background: The cause of the motor neuron (MN) death that drives terminal pathology in amyotrophic lateral sclerosis (ALS) remains unknown, and it is thought that the cellular environment of the MN may play a key role in MN survival. Several lines of evidence implicate vesicles in ALS, including that extracellular vesicles may carry toxic elements from astrocytes towards MNs, and that pathological proteins have been identified in circulating extracellular vesicles of sporadic ALS patients. Because MN degeneration at the neuromuscular junction is a feature of ALS, and muscle is a vesicle-secretory tissue, we hypothesized that muscle vesicles may be involved in ALS pathology. Methods: Sporadic ALS patients were confirmed to be ALS according to El Escorial criteria and were genotyped to test for classic gene mutations associated with ALS, and physical function was assessed using the ALSFRS-R score. Muscle biopsies of either mildly affected deltoids of ALS patients (n = 27) or deltoids of aged-matched healthy subjects (n = 30) were used for extraction of muscle stem cells, to perform immunohistology, or for electron microscopy. Muscle stem cells were characterized by immunostaining, RT-qPCR, and transcriptomic analysis. Secreted muscle vesicles were characterized by proteomic analysis, Western blot, NanoSight, and electron microscopy. The effects of muscle vesicles isolated from the culture medium of ALS and healthy myotubes were tested on healthy human-derived iPSC MNs and on healthy human myotubes, with untreated cells used as controls. Results: An accumulation of multivesicular bodies was observed in muscle biopsies of sporadic ALS patients by immunostaining and electron microscopy. Study of muscle biopsies and biopsy-derived denervation-naïve differentiated muscle stem cells (myotubes) revealed a consistent disease signature in ALS myotubes, including intracellular accumulation of exosome-like vesicles and disruption of RNA-processing. Compared with vesicles from healthy control myotubes, when administered to healthy MNs the vesicles of ALS myotubes induced shortened, less branched neurites, cell death, and disrupted localization of RNA and RNA-processing proteins. The RNA-processing protein FUS and a majority of its binding partners were present in ALS muscle vesicles, and toxicity was dependent on the expression level of FUS in recipient cells. Toxicity to recipient MNs was abolished by anti-CD63 immuno-blocking of vesicle uptake. Conclusions: ALS muscle vesicles are shown to be toxic to MNs, which establishes the skeletal muscle as a potential source of vesicle-mediated toxicity in ALS

    Muscle cells of sporadic amyotrophic lateral sclerosis patients secrete neurotoxic vesicles

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    BACKGROUND: The cause of the motor neuron (MN) death that drives terminal pathology in amyotrophic lateral sclerosis (ALS) remains unknown, and it is thought that the cellular environment of the MN may play a key role in MN survival. Several lines of evidence implicate vesicles in ALS, including that extracellular vesicles may carry toxic elements from astrocytes towards MNs, and that pathological proteins have been identified in circulating extracellular vesicles of sporadic ALS patients. Because MN degeneration at the neuromuscular junction is a feature of ALS, and muscle is a vesicle-secretory tissue, we hypothesized that muscle vesicles may be involved in ALS pathology. METHODS: Sporadic ALS patients were confirmed to be ALS according to El Escorial criteria and were genotyped to test for classic gene mutations associated with ALS, and physical function was assessed using the ALSFRS-R score. Muscle biopsies of either mildly affected deltoids of ALS patients (n = 27) or deltoids of aged-matched healthy subjects (n = 30) were used for extraction of muscle stem cells, to perform immunohistology, or for electron microscopy. Muscle stem cells were characterized by immunostaining, RT-qPCR, and transcriptomic analysis. Secreted muscle vesicles were characterized by proteomic analysis, Western blot, NanoSight, and electron microscopy. The effects of muscle vesicles isolated from the culture medium of ALS and healthy myotubes were tested on healthy human-derived iPSC MNs and on healthy human myotubes, with untreated cells used as controls. RESULTS: An accumulation of multivesicular bodies was observed in muscle biopsies of sporadic ALS patients by immunostaining and electron microscopy. Study of muscle biopsies and biopsy-derived denervation-naïve differentiated muscle stem cells (myotubes) revealed a consistent disease signature in ALS myotubes, including intracellular accumulation of exosome-like vesicles and disruption of RNA-processing. Compared with vesicles from healthy control myotubes, when administered to healthy MNs the vesicles of ALS myotubes induced shortened, less branched neurites, cell death, and disrupted localization of RNA and RNA-processing proteins. The RNA-processing protein FUS and a majority of its binding partners were present in ALS muscle vesicles, and toxicity was dependent on the expression level of FUS in recipient cells. Toxicity to recipient MNs was abolished by anti-CD63 immuno-blocking of vesicle uptake. CONCLUSIONS: ALS muscle vesicles are shown to be toxic to MNs, which establishes the skeletal muscle as a potential source of vesicle-mediated toxicity in ALS

    Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology

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    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons. A cross-ancestry genome-wide association meta-analysis of amyotrophic lateral sclerosis (ALS) including 29,612 patients with ALS and 122,656 controls identifies 15 risk loci with distinct genetic architectures and neuron-specific biology
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