Synchronization modulation increases transepithelial potentials in MDCK monolayers through Na/K pumps

Peer reviewedPublisher PD

Posible efecto protector renal de Solanum sisymbriifolium LAM. (SOLANACEAE) en ratas hipertensas por Nω-Nitro-L-Arginina metilester.

En este trabajo se propone evaluar la potencial actividad protectora renal del extracto bruto de la raíz de S. sisymbriifolium en ratas con hipertensión inducida por el Nω-Nitro-L-arginina metilester (L-NAME).CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI

Toxicidad sub crónica y actividad analgésica in vivo del extracto clorofórmico de las hojas de Calea urticifolia (Juanislama

Introduction: The population uses medicinal plants indiscriminately to treat diseases, with the believe that they are safe and lack adverse effects. Objective: To determine the in vivo toxicological and analgesic effect of the chloroform extract of Calea urticifolia leaves. Methodology: The toxicological study was performed using a 90- day sub-chronic toxicity test in NIH mice, at repeated and continuous doses. . Blood biochemistry, hematology and histopathological examination of organs were performed. The analgesic activity was evaluated in vivo using a model of abdominal contortions. Results: The administration of the plant extract caused the appearance of clinical signs of toxicity, alterations in hematic parameters and blood biochemistry, as well as histological alterations in some of organs. The analgesic activity at 100 mg/kg was similar to the Indomethacin drug. Conclusion: Despite the proven analgesic activity, according to the observed toxicological effects in this study, the prolonged use of Calea urticifolia leaves is not recommended for the treatment of diseasesIntroducción: La población utiliza la medicina a base de hierbas de forma indiscriminada basándose en la creencia de que las plantas medicinales carecen de efectos adversos. Objetivo: Determinar in vivo el efecto toxicológico y analgésico del extracto clorofórmico de las hojas de Calea urticifolia. Metodología: El estudio toxicológico fue realizado mediante la prueba de toxicidad subcrónica de 90 días, a dosis repetidas y continuas en ratones NIH. Se realizaron análisis de bioquímica sanguínea, hematología y el examen histopatológico de órganos. La actividad analgésica fue evaluada con el modelo in vivo de contorsiones abdominales. Resultados: La administración del extracto vegetal provocó la aparición de signos clínicos de toxicidad, alteraciones en los parámetros hematólogos y bioquímica sanguínea, además alteraciones histológicas en algunos de los órganos. La actividad analgésica a 100 mg/kg resultó comparable con el fármaco indometacina. Conclusión: Pese a la actividad analgésica demostrada, y de acuerdo a los efectos toxicológicos encontrados, no se recomienda el uso prolongado de las hojas de Calea urticifolia, para el tratamiento de enfermedade

Enzyme-Catalyzed Macrocyclization of Long Unprotected Peptides

A glutathione S-transferase (GST) catalyzed macrocyclization reaction for peptides up to 40 amino acids in length is reported. GST catalyzes the selective SNAr reaction between an N-terminal glutathione (GSH, γ-Glu-Cys-Gly) tag and a C-terminal perfluoroaryl-modified cysteine on the same polypeptide chain. Cyclic peptides ranging from 9 to 24 residues were quantitatively produced within 2 h in aqueous pH = 8 buffer at room temperature. The reaction was highly selective for cyclization at the GSH tag, enabling the combination of GST-catalyzed ligation with native chemical ligation to generate a large 40-residue peptide macrocycle.Massachusetts Institute of Technology (MIT startup funds)National Institutes of Health (U.S.) (grant GM101762)Damon Runyon Cancer Research Foundation (Award)Sontag Foundation (Distinguished Scientist Award)Amgen Inc. (Summer Graduate Research Fellowship

Intracellular iron uptake is favored in Hfe-KO mouse primary chondrocytes mimicking an osteoarthritis-related phenotype

HFE-hemochromatosis is a disease characterized by a systemic iron overload phenotype mainly associated with mutations in the HFE protein (HFE) gene. Osteoarthritis (OA) has been reported as one of the most prevalent complications in HFE-hemochromatosis patients, but the mechanisms associated with its onset and progression remain incompletely understood. In this study, we have characterized the response to high iron concentrations of a primary culture of articular chondrocytes isolated from newborn Hfe-KO mice and compared the results with that of a similar experiment developed in cells from C57BL/6 wild-type (wt) mice. Our data provide evidence that both wt- and Hfe-KO-derived chondrocytes, when exposed to 50 mu M iron, develop characteristics of an OA-related phenotype, such as an increased expression of metalloproteases, a decreased extracellular matrix production, and a lower expression level of aggrecan. In addition, Hfe-KO cells also showed an increased expression of iron metabolism markers and MMP3, indicating an increased susceptibility to intracellular iron accumulation and higher levels of chondrocyte catabolism. Accordingly, upon treatment with 50 mu M iron, these chondrocytes were found to preferentially differentiate toward hypertrophy with increased expression of collagen I and transferrin and downregulation of SRY (sex-determining region Y)-box containing gene 9 (Sox9). In conclusion, high iron exposure can compromise chondrocyte metabolism, which, when simultaneously affected by an Hfe loss of function, appears to be more susceptible to the establishment of an OA-related phenotype.European Regional Development FundEuropean Union (EU) [EMBRC.PT Alg-01-0145-FEDER-022121, Norte-01-0145-FEDER-000012]Fundacao para a Ciencia e a TecnologiaPortuguese Foundation for Science and Technology [SFRH/BD/77056/2011]Portuguese Foundation for Science and TechnologyPortuguese Foundation for Science and TechnologyPortuguese Science and Technology FoundationPortuguese Foundation for Science and Technologyinfo:eu-repo/semantics/publishedVersio

TREM2 is required for microglial instruction of astrocytic synaptic engulfment in neurodevelopment

Variants in the microglial receptor TREM2 confer risk for multiple neurodegenerative diseases. However, it remains unknown how this receptor functions on microglia to modulate these diverse neuropathologies. To understand the role of TREM2 on microglia more generally, we investigated changes in microglial function in Trem2−/− mice. We found that loss of TREM2 impairs normal neurodevelopment, resulting in reduced synapse number across the cortex and hippocampus in 1-month-old mice. This reduction in synapse number was not due directly to alterations in interactions between microglia and synapses. Rather, TREM2 was required for microglia to limit synaptic engulfment by astrocytes during development. While these changes were largely normalized later in adulthood, high fat diet administration was sufficient to reinitiate TREM2-dependent modulation of synapse loss. Together, this identifies a novel role for microglia in instructing synaptic pruning by astrocytes to broadly regulate appropriate synaptic refinement, and suggests novel candidate mechanisms for how TREM2 and microglia could influence synaptic loss in brain injury and disease

Transposon activation mutagenesis as a screening tool for identifying resistance to cancer therapeutics

Background: The development of resistance to chemotherapies represents a significant barrier to successful cancer treatment. Resistance mechanisms are complex, can involve diverse and often unexpected cellular processes, and can vary with both the underlying genetic lesion and the origin or type of tumor. For these reasons developing experimental strategies that could be used to understand, identify and predict mechanisms of resistance in different malignant cells would be a major advance. Methods: Here we describe a gain-of-function forward genetic approach for identifying mechanisms of resistance. This approach uses a modified piggyBac transposon to generate libraries of mutagenized cells, each containing transposon insertions that randomly activate nearby gene expression. Genes of interest are identified using next-gen high-throughput sequencing and barcode multiplexing is used to reduce experimental cost. Results: Using this approach we successfully identify genes involved in paclitaxel resistance in a variety of cancer cell lines, including the multidrug transporter ABCB1, a previously identified major paclitaxel resistance gene. Analysis of co-occurring transposons integration sites in single cell clone allows for the identification of genes that might act cooperatively to produce drug resistance a level of information not accessible using RNAi or ORF expression screening approaches. Conclusion: We have developed a powerful pipeline to systematically discover drug resistance in mammalian cells in vitro. This cost-effective approach can be readily applied to different cell lines, to identify canonical or context specific resistance mechanisms. Its ability to probe complex genetic context and non-coding genomic elements as well as cooperative resistance events makes it a good complement to RNAi or ORF expression based screens