La L-FABP moviliza el ácido araquidónico desde y hacia las gotas lipídicas nucleares

El núcleo es una estructura altamente dinámica formada por distintos compartimentos y dominios funcionales. En el núcleo, los lípidos se distribuyen en dos pooles: 1) La Envoltura Nuclear, que concentra al 95% de los Lípidos Polares (PL) (GP: glicerofosfolípidos + SL: esfingolípidos) y Colesterol (C). 2) Las Gotas Lipídicas Nucleares (N-LD) constituídas por un core hidrofóbico de lípidos neutros (TAG, CE y C) rodeado por una monocapa de PL, C y proteínas. Las N-LD se visualizan mediante tinción con Sudán Red y BODIPY493/503. Hemos mostrado que los lipídicos endonucleares poseen un metabolismo muy activo y podrían proveer ligandos endógenos al PPARα., a otros factores de transcripción y/o ser metabolizados a prostaglandinas y leucotrienos.Facultad de Ciencias Médica

Análisis de las proteínas de las gotas lipídicas nucleares

El Núcleo celular (N) es la adquisición evolutiva que define a las células eucariotas. En el núcleo, los lípidos se encuentran formando parte de dos pooles principales, la doble membrana nuclear compuesta de glicerofosfolípidos, esfingolípidos y colesterol, y dentro del N, la matriz nuclear, enriquecida en Lípidos Neutros (LN), y compuesta principalmente de TAG y CE. En nuestro laboratorio hemos identificado un nuevo dominio nuclear, las Gotas Lipídicas Nucleares (N-LD), donde se concentran los TAG y CE nucleares, y una monocapa lipoproteica, compuesta de fosfolípidos, colesterol y proteinas insertas en la misma. Ambos pooles lipídicos corresponden a fuentes alternativas con diferente composición química, propiedades físicas, regulación y funciones.Facultad de Ciencias Médica

Mucosal alcian blue positive mast cells in cecum from normal and splenectomized rabbits sensitized and challenged with ova

La sensibilización por vía intraperitoneal produce síntesis de IgE que se une a mastocitos. Los mastocitos mucosos, cuya proliferación depende de linfoquinas de células T, permanecen sensibilizados hasta 12 semanas. Un segundo contacto con el antígeno libera mediadores de hipersensibilidad local. La esplenectomía disminuye las inmunoglobulinas circulantes y modifica la respuesta inmunitaria. Por la cecotrofia, llegan al ciego moléculas en diferentes etapas de degradación, posibilitando el contacto de antígenos con la barrera mucosa. El objetivo del presente trabajo fue evaluar la cantidad de mastocitos mucosos detectables con azul alciano (AB) en el ciego de conejo normales y esplenectomizados, sensibilizados con Ovoalbúmina (OVA) y desafiados por vía oral. Conejos neozelandeses se dividieron en Grupo 1 (n=10) control no sensibilizado, Grupo 2 (n=10) sensibilizado intraperitonealmente en dos oportunidades con 2 ml de una solución de 70 µg de OVA y 30 mg de hidróxido de aluminio (ALUM)/ml, Grupo 3 (n=10) esplenectomizados y sensibilizados como el grupo 2. Los títulos de IgE específica anti-OVA fueron determinados por el test de anafilaxia cutánea pasiva. Los conejos de los grupos 2 y 3 fueron desafiados, previo ayuno de 24 horas, por instilación con sonda intragástrica, con 150 mg de OVA en 20 ml de PBS. Muestras de ciego, obtenidas 24 horas post desafío y fijadas en Carnoy se colorearon con AB pH < 1. Los mastocitos AB + se contaron en 20 campos en cada animal a 400X. El grupo 1 mostró 1,33 + 0,82 mastocitos por campo. El grupo 2: 12,88 + 2,17 (p< 0,05) y el grupo 3: 11,67 + 2,37 (p< 0,05). Los resultados muestran un marcado incremento de mastocitos mucosos en animales sensibilizados y desafiados que indicaría liberación de factores mediadores determinantes del reclutamiento mastocitario y que la esplenectomía no afectó el incremento mastocitario a nivel del ciego, con un comportamiento similar al del grupo no esplenectomizado.The intraperitoneal sensitization induces IgE synthesis which binds to mast cells. Mucosal mast cells proliferation depends on lymphokines from T cells and remains sensitized up to 12 weeks after contact with antigen. A second interaction with antigen produces the delivery of mediators which generate a local anaphylactic reaction. Splenectomy in rabbits determines a significant decrease in seric immunoglobulins as well as modification in the immune response. Cecotrophy is a particular mechanism of rabbit digestive physiology which allows the entire antigenic molecules to be in close contact with cecal mucosal barrier. The aim of the present work was to evaluate the number of Alcian Blue (AB)-positive mast cells in cecum form both normal and splenectomized rabbits, sensitized with OVA and oral challenge. New Zealand rabbits were divided into 3 groups: Group 1 (n=10) not sensitized control. Group 2 (n=10) was twice sensitized intraperitoneally with 2 ml of a 70 micrograms OVA and 30 mg aluminium hydroxide (ALUM)/ml PBS solution. Group 3 (n=10) was splenectomized and sensibitized as group 2. Anti-OVA IgE titers were determinate by Passive Cutaneous Anaphylaxis Test (PCA). Rabbits from groups 2 and 3 were challenged with 150 mg OVA in 20 ml PBS by instillation with an intragastric canula. Samples form cecum were fixed in Carnoy and stained with AB pH<1 24 hours after challenge. AB- positive mast cells were counted in 20 fields per animal at X400. Group 1 showed 1.33 + 0.82 mast cell per field; group 2: 12.88 + 2.17 (p<0.05); Group 3: 11.67 + 2.37 (p<0.05). Results showed, firstly, an important increase in the number of mucosal mast cell in sensibitized and challenged groups which indicates the delivery of chemoatractants for recruitment of mast cell and secondly, that splenectomy induces no modifications in such mast cell increase, as seen in the not-splenectomized group.Facultad de Ciencias Veterinaria

Mucosal alcian blue positive mast cells in cecum from normal and splenectomized rabbits sensitized and challenged with ova

La sensibilización por vía intraperitoneal produce síntesis de IgE que se une a mastocitos. Los mastocitos mucosos, cuya proliferación depende de linfoquinas de células T, permanecen sensibilizados hasta 12 semanas. Un segundo contacto con el antígeno libera mediadores de hipersensibilidad local. La esplenectomía disminuye las inmunoglobulinas circulantes y modifica la respuesta inmunitaria. Por la cecotrofia, llegan al ciego moléculas en diferentes etapas de degradación, posibilitando el contacto de antígenos con la barrera mucosa. El objetivo del presente trabajo fue evaluar la cantidad de mastocitos mucosos detectables con azul alciano (AB) en el ciego de conejo normales y esplenectomizados, sensibilizados con Ovoalbúmina (OVA) y desafiados por vía oral. Conejos neozelandeses se dividieron en Grupo 1 (n=10) control no sensibilizado, Grupo 2 (n=10) sensibilizado intraperitonealmente en dos oportunidades con 2 ml de una solución de 70 µg de OVA y 30 mg de hidróxido de aluminio (ALUM)/ml, Grupo 3 (n=10) esplenectomizados y sensibilizados como el grupo 2. Los títulos de IgE específica anti-OVA fueron determinados por el test de anafilaxia cutánea pasiva. Los conejos de los grupos 2 y 3 fueron desafiados, previo ayuno de 24 horas, por instilación con sonda intragástrica, con 150 mg de OVA en 20 ml de PBS. Muestras de ciego, obtenidas 24 horas post desafío y fijadas en Carnoy se colorearon con AB pH < 1. Los mastocitos AB + se contaron en 20 campos en cada animal a 400X. El grupo 1 mostró 1,33 + 0,82 mastocitos por campo. El grupo 2: 12,88 + 2,17 (p< 0,05) y el grupo 3: 11,67 + 2,37 (p< 0,05). Los resultados muestran un marcado incremento de mastocitos mucosos en animales sensibilizados y desafiados que indicaría liberación de factores mediadores determinantes del reclutamiento mastocitario y que la esplenectomía no afectó el incremento mastocitario a nivel del ciego, con un comportamiento similar al del grupo no esplenectomizado.The intraperitoneal sensitization induces IgE synthesis which binds to mast cells. Mucosal mast cells proliferation depends on lymphokines from T cells and remains sensitized up to 12 weeks after contact with antigen. A second interaction with antigen produces the delivery of mediators which generate a local anaphylactic reaction. Splenectomy in rabbits determines a significant decrease in seric immunoglobulins as well as modification in the immune response. Cecotrophy is a particular mechanism of rabbit digestive physiology which allows the entire antigenic molecules to be in close contact with cecal mucosal barrier. The aim of the present work was to evaluate the number of Alcian Blue (AB)-positive mast cells in cecum form both normal and splenectomized rabbits, sensitized with OVA and oral challenge. New Zealand rabbits were divided into 3 groups: Group 1 (n=10) not sensitized control. Group 2 (n=10) was twice sensitized intraperitoneally with 2 ml of a 70 micrograms OVA and 30 mg aluminium hydroxide (ALUM)/ml PBS solution. Group 3 (n=10) was splenectomized and sensibitized as group 2. Anti-OVA IgE titers were determinate by Passive Cutaneous Anaphylaxis Test (PCA). Rabbits from groups 2 and 3 were challenged with 150 mg OVA in 20 ml PBS by instillation with an intragastric canula. Samples form cecum were fixed in Carnoy and stained with AB pH<1 24 hours after challenge. AB- positive mast cells were counted in 20 fields per animal at X400. Group 1 showed 1.33 + 0.82 mast cell per field; group 2: 12.88 + 2.17 (p<0.05); Group 3: 11.67 + 2.37 (p<0.05). Results showed, firstly, an important increase in the number of mucosal mast cell in sensibitized and challenged groups which indicates the delivery of chemoatractants for recruitment of mast cell and secondly, that splenectomy induces no modifications in such mast cell increase, as seen in the not-splenectomized group.Facultad de Ciencias Veterinaria

Predominant Functional Expression of Kv1.3 by Activated Microglia of the Hippocampus after Status epilepticus

BACKGROUND:Growing evidence indicates that the functional state of microglial cells differs according to the pathological conditions that trigger their activation. In particular, activated microglial cells can express sets of Kv subunits which sustain delayed rectifying potassium currents (Kdr) and modulate differently microglia proliferation and ability to release mediators. We recently reported that hippocampal microglia is in a particular activation state after a status epilepticus (SE) and the present study aimed at identifying which of the Kv channels are functionally expressed by microglia in this model. METHODOLOGY/PRINCIPAL FINDINGS:SE was induced by systemic injection of kainate in CX3CR1(eGFP/+) mice and whole cell recordings of fluorescent microglia were performed in acute hippocampal slices prepared 48 h after SE. Microglia expressed Kdr currents which were characterized by a potential of half-maximal activation near -25 mV, prominent steady-state and cumulative inactivations. Kdr currents were almost abolished by the broad spectrum antagonist 4-Aminopyridine (1 mM). In contrast, tetraethylammonium (TEA) at a concentration of 1 mM, known to block Kv3.1, Kv1.1 and 1.2 subunits, only weakly reduced Kdr currents. However, at a concentration of 5 mM which should also affect Kv1.3 and 1.6, TEA inhibited about 30% of the Kdr conductance. Alpha-dendrotoxin, which selectively inhibits Kv1.1, 1.2 and 1.6, reduced only weakly Kdr currents, indicating that channels formed by homomeric assemblies of these subunits are not important contributors of Kdr currents. Finally, agitoxin-2 and margatoxin strongly inhibited the current. CONCLUSIONS/SIGNIFICANCE:These results indicate that Kv1.3 containing channels predominantly determined Kdr currents in activated microglia after SE

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Heavy and light roles: myosin in the morphogenesis of the heart

Myosin is an essential component of cardiac muscle, from the onset of cardiogenesis through to the adult heart. Although traditionally known for its role in energy transduction and force development, recent studies suggest that both myosin heavy-chain and myosin lightchain proteins are required for a correctly formed heart. Myosins are structural proteins that are not only expressed from early stages of heart development, but when mutated in humans they may give rise to congenital heart defects. This review will discuss the roles of myosin, specifically with regards to the developing heart. The expression of each myosin protein will be described, and the effects that altering expression has on the heart in embryogenesis in different animal models will be discussed. The human molecular genetics of the myosins will also be reviewed