Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes.

TRPV4 (transient receptor potential vanilloid 4) channels are Ca2+-permeable channels that play a key role in regulating vascular tone. In arterial myocytes, opening of TRPV4 channels creates local increases in Ca2+ influx, detectable optically as "TRPV4 sparklets." TRPV4 sparklet activity can be enhanced by the action of the vasoconstrictor angiotensin II (AngII). This modulation depends on the activation of subcellular signaling domains that comprise protein kinase C α (PKCα) bound to the anchoring protein AKAP150. Here, we used super-resolution nanoscopy, patch-clamp electrophysiology, Ca2+ imaging, and mathematical modeling approaches to test the hypothesis that AKAP150-dependent modulation of TRPV4 channels is critically dependent on the distance between these two proteins in the sarcolemma of arterial myocytes. Our data show that the distance between AKAP150 and TRPV4 channel clusters varies with sex and arterial bed. Consistent with our hypothesis, we further find that basal and AngII-induced TRPV4 channel activity decays exponentially as the distance between TRPV4 and AKAP150 increases. Our data suggest a maximum radius of action of ∼200 nm for local modulation of TRPV4 channels by AKAP150-associated PKCα

Crystallization Behavior and Morphology of Biodegradable Poly(ε-caprolactone)/Reduced Graphene Oxide Scaffolds

Morphology, thermal properties and the non-isothermal melt crystallization kinetics of biodegradable poly(ε-caprolactone) (PCL)/reduced graphene oxide (rGO) scaffolds are studied with differential scanning calorimetry (DSC) at various cooling rates (5, 10, 15 and 20 °C/min). Thermally induced phase separation was used to manufacture the scaffolds (TIPS). The micrographs show a more homogeneous and defined morphology with larger pores and thicker pore walls. The melting temperature (Tm), melting enthalpy (ΔHm), crystallization enthalpy (ΔHc) and degree of crystallinity (Xc) increased with the addition of rGO, suggesting larger and more perfect crystalline structures. The degree of crystallinity increased with the presence of rGO. The crystallization peak shifted to higher temperatures as the rGO concentration increased independently of the cooling rates. The peak shifted to lower temperatures as the cooling rate increased with the same rGO composition. The values of t1/2 (time needed to reach 50% crystallization) were lower for scaffolds with rGO. The values of the crystallization rate coefficient were higher when the porous support contained rGO, which indicates that their crystallization systems are faster. The activation energy obtained with the Kissinger method decreased with the presence of rGO. The results indicate that reduced graphene oxide acts as a nucleating agent in the non-isothermal melt crystallization process. The addition of small quantities of rGO changes their thermal properties with which they can be modified for application in the field of tissue engineering.This research was funded by the University of the Basque Country, grant number UPV/EHU2021

Genotyping strategies for maximizing genomic information in evaluations of the Latxa dairy sheep breed

Genomic selection has been implemented over the years in several livestock species, due to the achievable higher genetic progress. The use of genomic information in evaluations provides better prediction accuracy than do pedigree-based evaluations, and the makeup of the genotyped population is a decisive point. The aim of this work is to compare the effect of different genotyping strategies (number and type of animals) on the prediction accuracy for dairy sheep Latxa breeds. A simulation study was designed based on the real data structure of each population, and the phenotypic and genotypic data obtained were used in genetic (BLUP) and genomic (single-step genomic BLUP) evaluations of different genotyping strategies. The genotyping of males was beneficial when they were genetically connected individuals and if they had daughters with phenotypic records. Genotyping females with their own lactation records increased prediction accuracy, and the connection level has less relevance. The differences in genotyping females were independent of their estimated breeding value. The combined genotyping of males and females provided intermediate accuracy results regardless of the female selection strategy. Therefore, assuming that genotyping rams is interesting, the incorporation of genotyped females would be beneficial and worthwhile. The benefits of genotyping individuals from various generations were highlighted, although it was also possible to gain prediction accuracy when historic individuals were not considered. Greater genotyped population sizes resulted in more accuracy, even if the increase seems to reach a plateau

Reparación y mantenimiento del casco del buque

Nivel educativo: Grado. Duración (en horas): De 41 a 50 horasA fin de que un buque conserve su estado operacional, en cumplimiento de las disposiciones legales nacionales, así como para mantener la clase certificada por la Sociedad Clasificadora, es necesario que periódicamente realice entradas en dique seco. Durante las mismas se realizan las operaciones necesarias de mantenimiento de casco y maquinaria y se realizan las inspecciones preceptivas. Habitualmente, es la propia Sociedad Clasificadora la que establece el calendario de inspeciones que debe cumplir el buque. Los estudiantes se encuentran navegando en un buque y representan la oficialidad del Departamento de Máquinas del buque. La jefa de máquinas ha recibido una petición de la compañía naviera para la elaboración de un informe técnico de las operaciones de reparación y mantenimiento del casco del buque que se deben realizar. El objetivo del informe es pedir presupuesto en diferentes astilleros. Los estudiantes divididos en equipos de trabajo de 4 ó 5 personas deberán elaborar el informe técnico de acuerdo con el barco en el que navegan (quimiquero, granelero, petrolero, gasero, etc..) y con los años de servicio del mismo

Resultados perinatales en gestantes con déficit de proteína s coagulativa tratadas con heparina de bajo peso molecular

Estudios epidemiológicos realizados sugieren que las gestantes afectas de trombofilia, tanto hereditaria como adquirida, presentan peores resultados perinatales que las gestantes sanas. El mecanismo patogénico sugerido para el desarrollo de estas complicaciones se basa en la presencia de una insuficiencia útero-placentaria debida a un compromiso del sistema vascular. Desde hace años, la heparina de bajo peso molecular se utiliza en embarazadas tanto profilácticamente como a dosis terapéuticas para anticoagulación. Su buena biodisponibilidad, vida media más prolongada y el bajo riesgo relativo de trombocitopenia y osteoporosis la han convertido en la terapia de elección frente a la heparina no fraccionada. El carácter trombótico de las lesiones subyacentes a la vasculopatía, así como una amplia experiencia en el uso de heparina de bajo peso molecular durante la gestación sumados a la alta prevalencia de déficit de proteína S en nuestras gestantes y a la relación de dicha trombofilia con los resultados perinatales adversos, nos han llevado a plantearnos si las gestantes afectas de déficit de proteína S coagulativa tratadas con heparina de bajo peso molecular presentan resultados perinatales similares a la población gestante sana. Para ello hemos elaborado un estudio analítico de cohortes históricas, en el que se han incluido un total de 18.244 embarazadas. Esta muestra se distribuye en tres grupos. El primero corresponde a gestantes con déficit de PS sin otra patología médica asociada, tratadas con HBPM(n:328). El segundo grupo corresponde a gestantes sanas, sin déficit de PS ni otra patología médica asociada(n:11.884) y un tercer grupo corresponde a la población de referencia que incluye a gestantes que no padecen déficit de PS con independencia de que padezcan o no otra patología médica(n:17.916). Las pacientes con déficit de proteína S tratadas con HBPM presentan un riesgo de preeclampsia similar al encontrado en la población sana, aunque debido a la baja incidencia de preeclampsia en nuestro medio se requieren estudios con un tamaño muestral mayor para confirmar este hallazgo. El riesgo de que una gestante con déficit de proteína S tratada con HBPM dé a luz un recién nacido con CIR es similar al hallado en la población de referencia. No existen diferencias en el riesgo de que el parto finalice mediante la realización de cesárea entre las gestantes con déficit de proteína S tratadas con HBPM y la población de referencia. Dada la ausencia de casos de DPPNI en el grupo de gestantes sanas, no ha sido posible evaluar ninguna asociación. Sin embargo, podemos afirmar que el riesgo de DPPNI en el grupo de estudio no es significativamente mayor que en la población de referencia

Dynamic L-type CaV1.2 channel trafficking facilitates CaV1.2 clustering and cooperative gating.

L-type CaV1.2 channels are key regulators of gene expression, cell excitability and muscle contraction. CaV1.2 channels organize in clusters throughout the plasma membrane. This channel organization has been suggested to contribute to the concerted activation of adjacent CaV1.2 channels (e.g. cooperative gating). Here, we tested the hypothesis that dynamic intracellular and perimembrane trafficking of CaV1.2 channels is critical for formation and dissolution of functional channel clusters mediating cooperative gating. We found that CaV1.2 moves in vesicular structures of circular and tubular shape with diverse intracellular and submembrane trafficking patterns. Both microtubules and actin filaments are required for dynamic movement of CaV1.2 vesicles. These vesicles undergo constitutive homotypic fusion and fission events that sustain CaV1.2 clustering, channel activity and cooperative gating. Our study suggests that CaV1.2 clusters and activity can be modulated by diverse and unique intracellular and perimembrane vesicular dynamics to fine-tune Ca2+ signals

Influence of rGO on the Crystallization Kinetics, Cytoxicity, and Electrical and Mechanical Properties of Poly (L-lactide-co-ε-caprolactone) Scaffolds

Biodegradable scaffolds of poly (L-lactide-co-ε-caprolactone) (PLCL) and reduced graphene oxide (rGO) were prepared by TIPS (thermally induced phase separation). The nonisothermal cold crystallization kinetics were investigated by differential scanning calorimetry (DSC) with various cooling rates. The experimental values indicate that nonisothermal crystallization improves with cooling rate, but the increasing rGO concentration delays crystallization at higher temperatures. The activation energies were calculated by the Kissinger equation; the values were very similar for PLCL and for its compounds with rGO. The electrical conductivity measurements show that the addition of rGO leads to a rapid transition from insulating to conductive scaffolds with a percolation value of ≈0.4 w/w. Mechanical compression tests show that the addition of rGO improves the mechanical properties of porous substrates. In addition, it is an anisotropic material, especially at compositions of 1% w/w of rGO. All of the samples with different rGO content up to 1% are cytotoxic for C2C12 myoblast cells.This work was supported by the University of The Basque Center. The authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program. This work has been also supported by FCT–Fundação para a Ciência e Tecnologia (FCT) under the scope of the strategic funding of UID/FIS/04650/2020 and UIDB/04469/2020 units and project PTDC/BTM-MAT/28237/2017

Kv2.1 channels play opposing roles in regulating membrane potential, Ca2+ channel function, and myogenic tone in arterial smooth muscle.

The accepted role of the protein Kv2.1 in arterial smooth muscle cells is to form K+ channels in the sarcolemma. Opening of Kv2.1 channels causes membrane hyperpolarization, which decreases the activity of L-type CaV1.2 channels, lowering intracellular Ca2+ ([Ca2+]i) and causing smooth muscle relaxation. A limitation of this model is that it is based exclusively on data from male arterial myocytes. Here, we used a combination of electrophysiology as well as imaging approaches to investigate the role of Kv2.1 channels in male and female arterial myocytes. We confirmed that Kv2.1 plays a canonical conductive role but found it also has a structural role in arterial myocytes to enhance clustering of CaV1.2 channels. Less than 1% of Kv2.1 channels are conductive and induce membrane hyperpolarization. Paradoxically, by enhancing the structural clustering and probability of CaV1.2-CaV1.2 interactions within these clusters, Kv2.1 increases Ca2+ influx. These functional impacts of Kv2.1 depend on its level of expression, which varies with sex. In female myocytes, where expression of Kv2.1 protein is higher than in male myocytes, Kv2.1 has conductive and structural roles. Female myocytes have larger CaV1.2 clusters, larger [Ca2+]i, and larger myogenic tone than male myocytes. In contrast, in male myocytes, Kv2.1 channels regulate membrane potential but not CaV1.2 channel clustering. We propose a model in which Kv2.1 function varies with sex: in males, Kv2.1 channels control membrane potential but, in female myocytes, Kv2.1 plays dual electrical and CaV1.2 clustering roles. This contributes to sex-specific regulation of excitability, [Ca2+]i, and myogenic tone in arterial myocytes