D609 inhibition of phosphatidylcholine-specific phospholipase C attenuates prolonged insulin stimulation-mediated GLUT4 downregulation in 3T3-L1 adipocytes

Glucose uptake is stimulated by insulin via stimulation of glucose transporter 4 (GLUT4) translocation to the plasma membrane from intracellular compartments in adipose tissue and muscles. Insulin stimulation for prolonged periods depletes GLUT4 protein, particularly in highly insulin-responsive GLUT4 storage vesicles. This depletion mainly occurs via H2O2-mediated retromer inhibition. However, the post-receptor mechanism of insulin activation of oxidative stress remains unknown. Here, we show that phosphatidylcholine-specific phospholipase C (PC-PLC) plays an important role in insulin-mediated downregulation of GLUT4. In the study, 3T3-L1 adipocytes were exposed to a PC-PLC inhibitor, tricyclodecan-9-yl-xanthogenate (D609), for 30 min prior to the stimulation with 500 nM insulin for 4 h, weakening the depletion of GLUT4. D609 also prevents insulin-driven H2O2 generation in 3T3-L1 adipocytes. Exogenous PC-PLC and its product, phosphocholine (PCho), also caused GLUT4 depletion and promoted H2O2 generation in 3T3-L1 adipocytes. Furthermore, insulin-mediated the increase in the cellular membrane PC-PLC activity was observed in Amplex Red assays. These results suggested that PC-PLC plays an important role in insulin-mediated downregulation of GLUT4 and that PCho may serve as a signaling molecule. (AU)

PLCE1 alleviates lipopolysaccharide-induced acute lung injury by inhibiting PKC and NF-kB signaling pathways

Background: Acute lung injury (ALI) is a clinical syndrome characterized by hyperosmotic ­pulmonary­edema­and­ increased­alveolar­fluid.­Phospholipase­C­ epsilon-1­(PLCE1),­identified­as a member of phospholipase family, and the relationship between PLCE1 and lung injury is n ot clear.Objective: To assess the possible role of Phospholipase C Epsilon 1 (PLCE1) in Acute lung injury (ALI) progression and related mechanisms. Materials and methods:­ The­ effects­of­ LPS­ and­ PLCE1­on­ cell­ viability­and­ apoptosis­were­examined­by­ MTT­ and­ flow­ cytometry.­Also,­ the­ level­ of­ PLCE1­was­ controlled­by­ transfection­of­ its­ plasmid­and­ shRNA.­The­ inflammatory­response­in­ response­to­ PLCE1­overexpression­or­ablation was analyzed by quantitative PCR and ELISA assay. And the involvement of PKC and NF-κB­signal­pathway­were­detected­by­Immunoblot.­Results: In this study, we developed a LPS-induced ALI cell model. We found PLCE1 was upreg-ulated­in­ LPS-induced­pneumonia­cells­ and­ affected­cell­ viability.­Also,­knockdown­of­ PLCE1­reduced LPS-induced apoptosis of pneumonia cells. In addition, depletion of PLCE1 suppressed LPS-induced­secretion­of­ proinflammatory­cytokines­in­ pneumonia­cells.­Mechanically,­we­found­depletion­of­ PLCE1­inhibited­PKC­ and­ NF-κB­signal­pathway,­and­ therefore­alleviated­LPS-induced ALI.Conclusion: We therefore thought PLCE1 co (AU)uld serve as a promising drug for ALI

Actualización en el manejo de fármacos vasoactivos en insuficiencia cardiaca aguda y shock cardiogénico y mixto / Update on the use of vasoactive drugs for acute heart failure and cardiogenic and undifferentiated shock

Los fármacos vasoactivos poseen propiedades inotrópicas y vasomotoras. La variabilidad de su respuesta se explica por múltiples factores relacionados con la dosis empleada, la densidad, la afinidad y la selectividad de sus receptores, así como por las complejas vías de señalización. Su indicación no solo debería recaer en un umbral de presión arterial recomendado, sino también en parámetros objetivos de microcirculación. Hasta el momento no se ha demostrado que ningún fármaco vasoactivo aumente la supervivencia, y la crítica más importante es por los graves efectos adversos. Las líneas de investigación se han centrado en la búsqueda de fármacos más selectivos intentando evitar estos efectos adversos y no solo buscando la mejoría sintomática y hemodinámica a corto plazo (AU)

Vasoactive drugs can have inotropic or vasomotor properties or both. Variability in responses to these drugs can be explained by factors related to the dose used, the drugs’ affinity for specific receptors, the density and selectivity of these receptors, and the operation of complex signaling pathways. Indications for their use should not be based solely on recommended blood pressure thresholds but should also take into account objective microcirculatory parameters. To date, no vasoactive drug has been shown to increase survival, and the main criticism of their use is that they produce serious adverse effects. Research has focused on finding more selective compounds that will avoid these adverse effects and has not only sought to achieve short-term improvements in symptoms and hemodynamics (AU)

Vias de sinalização reguladoras das funções do espermatozoide / Signaling pathways in sperm functions regulation

O espermatozoide é o gâmeta masculino e, como tal, a sua principal func¸ão é fecundar o oócito. Aquando da ejaculac¸ão, esta célula ainda não se encontra madura, pelo que não consegue realizar a sua func¸ão. Ao entrar em contato com o trato reprodutor feminino, o espermatozoide sofre a capacitac¸ão. Este processo é caracterizado por alterac¸ões bioquímicas e funcionais. A reac¸ão acrossómica é o processo final para a fecundac¸ão e caracteriza-se pela libertac¸ão das enzimas de proteolíticas que hidrolisam a zona pelúcida. Todos estes processos dependem de vias de sinalizac¸ão. A maioria das vias de sinalizac¸ão descritas para células somáticas já foram identificadas no espermatozoide, contudo, os seus efeitos não são completamente conhecidos. Nesta revisão serão descritas as principais vias de sinalizac¸ão dos espermatozoides, nomeadamente PPP1CC2, cAMP/PKA, fosfolipase C, PI3K-AKT e ROS (AU)

Spermatozoon is the male gamete and its main function is to fertilize the oocyte. When ejaculation occurs, this cell is immature and therefore cannot perform its function. When it contacts the female reproductive tract, the sperm undergoes capacitation. This process is characterized by biochemical and functional changes. The acrosome reaction is the last process for fertilization and it is characterized by the release of proteolytic enzymes which hydrolyze the zona pellucida. All of these processes depend of signaling pathways. Most of the signaling pathways described for somatic cells have been identified in the sperm, but their effects are not completely known. In this review the main signaling pathways of sperm are described, including PPP1CC2, cAMP/PKA, phospholipase C, PI3K-AKT and ROS (AU)

Orexin A-induced extracellular calcium influx in prefrontal cortex neurons involves L-type calcium channels

Orexins, novel excitatory neuropeptides from the lateral hypothalamus, have beenstrongly implicated in the regulation of sleep and wakefulness. In this study, weexplored the effects and mechanisms of orexin A on intracellular free Ca2+ concentration([Ca2+]i) of freshly dissociated neurons from layers V and VI in prefrontalcortex (PFC). Changes in [Ca2+]i were measured with fluo-4/AM using confocallaser scanning microscopy. The results revealed that application of orexin A (0.1 ~1ìM) induced increase of [Ca2+]i in a dose-dependent manner. This elevation of[Ca2+]i was completely blocked by pretreatment with selective orexin receptor 1antagonist SB 334867. While depletion of intracellular Ca2+ stores by the endoplasmicreticulum inhibitor thapsigargin (2 ìM), [Ca2+]i in PFC neurons showed noincrease in response to orexin A. Under extracellular Ca2+-free condition, orexin Afailed to induce any changes of Ca2+ fluorescence intensity in these acutely dissociatedcells. Our data further demonstrated that the orexin A-induced increase of [Ca2+]iwas completely abolished by the inhibition of intracellular protein kinase C or phospholipaseC activities using specific inhibitors, BIS II (1 ìM) and D609 (10 ìM),respectively. Selective blockade of L-type Ca2+ channels by nifedipine (5 ìM) significantlysuppressed the elevation of [Ca2+]i induced by orexin A. Therefore, thesefindings suggest that exposure to orexin A could induce increase of [Ca2+]i in neuronsfrom deep layers of PFC, which depends on extracellular Ca2+ influx via L-typeCa2+ channels through activation of intracellular PLC-PKC signaling pathway bybinding orexin receptor 1(AU)

Depresión y sistemas de generación de segundos mensajeros / Depression and seconf messenger systems

No disponible

Diagnóstico e investigación epidemiológica de un brote de toxiinfección alimentaria causado por clostridium perfringens / Diagnosis and epidemiological investigation of an outbreak of Clostridium perfringens food poisoning

FUNDAMENTO. Aunque Clostridium perfringens es un agente clásico de toxiinfección alimentaria, la levedad y el carácter autolimitado del cuadro limita con frecuencia su confirmación microbiológica. Este estudio describe la investigación de un brote de diarrea por C. perfringens ocurrido en un establecimiento público de hostelería. MÉTODOS. Se realizó una encuesta epidemiológica y una inspección del establecimiento. Para los distintos alimentos consumidos se calcularon las tasas específicas de ataque. La causalidad independiente de cada plato se estableció calculando las odds ratio ajustadas mediante un modelo de regresión logística. La investigación de la toxina de Clostridium perfringens en heces de 4 enfermos y de un sujeto expuesto asintomático se realizó por aglutinación pasiva reversa por látex. RESULTADOS. La tasa global de ataque fue del 70,8 por ciento. La sintomatología consistió fundamentalmente en diarrea (100 por ciento) y dolor abdominal (94 por ciento). Se detectaron diferencias significativas en las tasas específicas de ataque para el consumo de diferentes platos. Sin embargo, la contribución independiente de cada uno de ellos sólo resultó significativa para el consumo de "ravioli con salsa de queso". La detección fecal de enterotoxina de C.perfringens resultó positiva en los 4 enfermos estudiados, pero no en el sujeto expuesto y asintomático. CONCLUSIONES. En este brote la tasa global de ataque fue alta. La sintomatología concuerda con los datos previamente publicados. El análisis epidemiológico implicó a los "ravioli con salsa de queso" como alimento responsable y la investigación clínica, junto con la detección de la toxina en heces, permitieron identificar a C.perfringens como el agente etiológico (AU)

La Citometría de Flujo en el Análisis de las Plaquetas. (I) Aspectos Estructurales y Funcionales de las Plaquetas / The flow cytometry in the functional analysis of the platelets. (I) Structure and function

No disponible