Función de la fosfatasa de fosfolípidos 3 (LPP3) en las etapas tempranas de la vía secretora

El complejo de Golgi participa en el procesamiento, la distribución y el transporte de lípidos y proteínas hacia su destino final dentro de la célula. El transporte desde el Golgi está mediado por intermediarios de transporte (ITs), principalmente vesículas y túbulos. La formación de ITs se inicia con la gemación de la vesícula o el túbulo, a continuación se produce su elongación y finalmente tiene lugar su fisión. Este proceso requiere de una compleja maquinaria molecular en la que intervienen las llamadas proteínas de cubierta, proteínas motoras asociadas al citoesqueleto, y los lípidos de las membranas. Respecto al papel de los lípidos, éstos pueden actuar tanto en el reclutamiento de proteínas citosólicas que participan en la formación de los ITs, como dotando a la membrana de las propiedades físicas óptimas para su deformación en vesículas o túbulos. La curvatura de membrana está facilitada por lípidos con estructura cónica como el ácido lisofosfatídico (LPA), el ácido fosfatídico (PA) y el diacilglicerol (DAG). El DAG cumple una doble función en la formación de ITs desde el Golgi: por una parte actúa en el reclutamiento y la activación de la proteína cinasa D (PKD), necesaria para la correcta fisión de vesículas desde la red trans-Golgi (TGN). Por otra parte ayuda a la formación de curvatura negativa. El DAG en el Golgi está estrechamente regulado por diferentes vías que controlan su formación y metabolismo. Una de estas vías está mediada por las llamadas fosfatasas del ácido fosfatídico (PAPs), que producen DAG a partir de defosforilar el PA. Existen dos familias de proteínas que actúan como fosfatasas del ácido fosfatídico. Las enzimas de la familia PAP1son citosólicas, su actividad catalítica es dependiente de Mg+2, se inhiben por N-etilmaleimida (NSF) y el PA es su único sustrato. Las enzimas PAP2 son proteínas transmembrana, independientes de Mg+2 e insensibles a NSF. Las PAP2 también se conocen como fosfatasas de lípidos fosfato (LPPs), ya que además del PA pueden también catalizar la defosforilación de otros lípidos como la ceramida-1-fosfato (C1P), la esfingosina-1-fosfato (S1P) y el ácido lisofosfatídico (LPA), aunque con diferentes afinidades (PA ~ LPA > C1P > S1P). La inhibición de las PAP por el agente farmacológico propanolol, indica que el DAG que proviene de esta vía es necesario para la formación de ITs desde el Golgi al retículo endoplasmático (RE). En esta tesis hemos demostrado que uno de los miembros de la familia PAP2, la enzima PAP2b, también conocida como LPP3, se localiza en diferentes compartimentos de la vía secretora, desde los sitios de salida del RE (ERES) hasta el complejo de Golgi. El silenciamiento de LPP3: (i) reduce la formación de túbulos desde el compartimento intermedio entre el RE y el Golgi (ERGIC) y el complejo de Golgi, y a su vez incrementa la longitud de aquéllos túbulos formados desde el Golgi; (ii) causa un retraso en el transporte dependiente de Rab6 de la subunidad B de la toxina Shiga desde el Golgi al RE, sin afectar al transporte anterógrado de RE a Golgi; y (iii) a nivel ultraestructural incrementa el número de perfiles vesiculares asociados a las cisternas del Golgi. El silenciamiento de la LPP3 también reduce la síntesis de novo de DAG y los niveles de DAG en el Golgi. Además, también hemos demostrado que la sobreexpresión de un mutante catalíticamente inactivo de la LPP3 reproduce los efectos observados tanto con el silenciamiento de la LPP3, como al inhibir la actividad catalítica de las PAP2 por el propanolol. De forma conjunta, nuestros resultados demuestran que la LPP3, a partir de regular la homeostasis de DAG, participa en la formación de ITs en diferentes compartimentos de la vía secretora, regulando el transporte retrógrado entre el RE y el Golgi.The Golgi complex is involved in the processing, sorting and transport of membrane components (lipids and proteins) to appropriate subcellular destinations, and is also a membranous platform for signalling, metabolic and cytoskeleton proteins. Transport to and from the Golgi complex is mediated by transport carriers (vesicles and/or tubules), which are generated in sequential stages beginning with the formation of a bud, followed by its elongation, constriction and final fission. Lipids play an essential role in this process through different mechanisms: they can recruit cytosolic proteins, modulate protein functions and modify the architecture and physical properties of the membrane bilayer. Thus, membrane curvature is facilitated by conical lipid molecules such as lysophosphatidic acid (LPA), phosphatidic acid (PA) and diacylglycerol (DAG). In previous results of our group we have demonstrated that the DAG produced by the phosphatidic acid phosphatase type 2 family of proteins (PAP2) is necessary for the retrograde transport from the Golgi to the endoplasmic reticulum (ER). In this thesis we have demonstrated that that the PAP2 family member lipid phosphate phosphatase 3 (LPP3, also known as PAP2b) localizes in compartments of the secretory pathway from ER export sites to the Golgi complex. The depletion of human LPP3: (i) reduces the number of tubules generated from the ER–Golgi intermediate compartment and the Golgi, with those formed from the Golgi being longer in LPP3-silenced cells than in control cells; (ii) impairs the Rab6-dependent retrograde transport of Shiga toxin subunit B from the Golgi to the ER, but not the anterograde transport of VSV-G or ssDsRed; and (iii) induces a high accumulation of Golgi-associated membrane buds. LPP3 depletion also reduces levels of de novo synthesized DAG and the Golgi-associated DAG contents. Remarkably, overexpression of a catalytically inactive form of LPP3 mimics the effects of LPP3 knockdown on Rab6-dependent retrograde transport. We conclude that LPP3 participates in the formation of retrograde transport carriers at the ER–Golgi interface, where it transitorily cycles, and during its route to the plasma membrane

Disentangling the formation of contrasting tree line physiognomies combining model selection and Bayesian parameterization for simulation models.

Alpine tree-line ecotones are characterized by marked changes at small spatial scales that may result in a variety of physiognomies. A set of alternative individual-based models was tested with data from four contrasting Pinus uncinata ecotones in the central Spanish Pyrenees to reveal the minimal subset of processes required for tree-line formation. A Bayesian approach combined with Markov chain Monte Carlo methods was employed to obtain the posterior distribution of model parameters, allowing the use of model selection procedures. The main features of real tree lines emerged only in models considering nonlinear responses in individual rates of growth or mortality with respect to the altitudinal gradient. Variation in tree-line physiognomy reflected mainly changes in the relative importance of these nonlinear responses, while other processes, such as dispersal limitation and facilitation, played a secondary role. Different nonlinear responses also determined the presence or absence of krummholz, in agreement with recent findings highlighting a different response of diffuse and abrupt or krummholz tree lines to climate change. The method presented here can be widely applied in individual-based simulation models and will turn model selection and evaluation in this type of models into a more transparent, effective, and efficient exercise

Una mirada atrás

Treballs de l'alumnat del Grau de Comunicació Audiovisual, Facultat de Biblioteconomia i Documentació, Universitat de Barcelona, Projectes I - Grup7. Curs: 2014-2015, Tutor: Jaume VilasecaDirector: Carla Martínez; Aj. direcció: Enric Bartra ; Productor: Carla Lombardo; Guionista: Carla Lombardo; Director de fotografia: MAria Rodríguez; Camera: Sara Bernal; Aj. Camera: Enric Bartra; Il·luminador: Aina Gutiérrez; Direcció artística: Sara Bernal; Direcció de so: Maria Rodríguez; Muntatge: Sara Bernal; Música: Carla Martínez; Postproducció: Sara Bernal; Equip artístic: Personatge: Pare Gaspar, Actor/Actriu: Enric Bartra; Personatge: Milicià 1, Actor/Actriu: Aina Gutiérrez; Personatge: Milicià 2, Actor/Actriu: Carla Martínez; Personatge: Germana Gaspar, Actor/Actriu: Sara Bernal.[Vídeo] Gaspar Lombardo explica com va viure la Guerra Civil Espanyola quan tenia només 7 anys. Va patir la pèrdua del seu pare a mans de dos miliciansi va veure com propietats i terres de la seva família els hi eren expropiades.[Memòria] En primera instancia, hemos decidido tratar la experiencia que vivió la generación de nuestros abuelos durante la Guerra Civil Española. A partir de aquí, nos hemos acogido al género documental para narrar las vivencias de esos años, con la idea u objetivo principal de mostrar la historia contada en primera persona por alguien que vivió el conflicto bélico o las carencias emocionales y económicas sufridas en la posguerra. Escoger el género documental nos ha permitido expresar con mayor eficacia el hilo argumental del relato. Además, a través de la entrevista hay una conexión más cercana con el público ya que el protagonista y su narración son reales y no están interpretados por un actor. También hemos querido complementar la entrevista con fragmentos ficcionados de las palabras del protagonista, con la intención de causar mayor impacto en el espectador. Después de comparar las historias de los posibles entrevistados, hemos elegido la de Gaspar Lombardo Mata porque es la que mejor plasma la dureza de la Guerra Civil: con solo siete años sufrió la pérdida de su padre en manos de unos milicianos. Debido al contenido dramático y la temática principal, este documental va dirigido al público adulto, ya que relata un hecho muy presente en la sociedad española

RiSD: a methodology for building i* strategic dependency models

Goal-oriented models have become a consolidated type of artefact in various software and knowledge engineering activities. Several languages exist for representing such type of models but there is a lack of associated methodologies for guiding their construction up to the necessary level of detail. In this paper we present RiSD, a methodology for building Strategic Dependency (SD) models in the i* notation. RiSD is defined in a prescriptive way to reduce uncertainness when constructing the model. RiSD also tackles two fundamental issues: on the one hand, it tends to reduce the average size of the resulting models and, on the other hand, it allows including some traceability relationships in the resulting models. As a result, we may say that RiSD increases the understandability of goal-oriented models whilst improving all construction.Peer ReviewedPostprint (author’s final draft

A comparative analisys of i*-based agent-oriented modeling languages

Agent-oriented models are frequently used in disciplines such as requirements engineering and organizational process modelling. i* is currently one of the most widespread notations used for this purpose. Due to its strategic nature, instead of a single definition, there exist several versions and variants, often not totally defined and even contradictory. In this paper we present a comparative study of the three most widespread i* variants: Eric Yu’s seminal proposal, the Goal-oriented Requirement Language (GRL) and the language used in the TROPOS method. Next, we propose a generic conceptual model to be used as reference framework of these three variants and we show its use for generating specific models for the three mentioned variants, as well as for other existing proposals.Peer ReviewedPostprint (author’s final draft

Cannabinoid receptor CB2 drives HER2 pro-oncogenic signaling in breast cancer

Pharmacological activation of cannabinoid receptors elicits antitumoral responses in different models of cancer. However, the biological role of these receptors in tumor physio-pathology is still unknown. We analyzed CB2 cannabinoid receptor protein expression in two series of 166 and 483 breast tumor samples operated in the University Hospitals of Kiel, Tübingen and Freiburg between 1997 and 2010. CB2 mRNA expression was also analyzed in previously published DNA microarray datasets. The role of CB2 in oncogenesis was studied by generating a mouse line that expresses the HER2 rat ortholog (neu) and lacks CB2, and by a variety of biochemical and cell biology approaches in human breast cancer cells in culture and in vivo, upon modulation of CB2 expression by si/shRNAs and overexpression plasmids. CB2-HER2 molecular interaction was studied by co-localization, coimmunoprecipitation and proximity ligation assays. We show an association between elevated CB2 expression in HER2+ breast tumors and poor patient prognosis. We also demonstrate that genetic inactivation of CB2 impairs tumor generation and progression in MMTV-neu mice. Moreover, we show that HER2 upregulates CB2 expression by activating the transcription factor ELK1 via the ERK cascade, and that an increased CB2 expression activates the HER2 prooncogenic signaling machinery at the level of the tyrosine kinase c-SRC. Finally, HER2 and CB2 form heteromers in cancer cells. Our findings reveal an unprecedented role of CB2 as a pivotal regulator of HER2 pro-oncogenic signaling in breast cancer, and suggest that CB2 may be a biomarker with prognostic value in these tumors

Análisis comparativo de lenguajes de modelado orientados a objetivos basados en i*

Los modelos orientados a objetivos son usados frecuentemente en disciplinas tales como la ingeniería de requisitos o el modelado de procesos en organizaciones. i* es una de las notaciones más empleadas para construir este tipo de modelos. Desafortunadamente, no existe una definición única de i* sino diferentes versiones y variantes que, con frecuencia, no están totalmente definidas dificultando su comprensión y utilización. En este artículo, se presenta un estudio comparativo de las tres variantes más utilizadas de i*: la propuesta original de Eric Yu, el lenguaje GRL y el lenguaje utilizado en el método TROPOS. A continuación, se formula un modelo conceptual genérico como marco de referencia de las variantes estudiadas, se muestra cómo a partir de este modelo genérico pueden generarse los modelos específicos de cada una, y se evidencia que también puede usarse para clasificar algunas variantes puntuales que encontramos en la literatura.Peer ReviewedPostprint (author's final draft

The avoidance of G-CSF and the addition of prophylactic corticosteroids after autologous stem cell transplantation for multiple myeloma patients appeal for the at-home setting to reduce readmission for neutropenic fever

Background Autologous stem cell transplantation (ASCT) remains the standard of care for young multiple myeloma (MM) patients; indeed, at-home ASCT has been positioned as an appropriate therapeutic strategy. However, despite the use of prophylactic antibiotics, neutropenic fever (NF) and hospital readmissions continue to pose as the most important limitations in the outpatient setting. It is possible that the febrile episodes may have a non-infectious etiology, and engraftment syndrome could play a more significant role. The aim of this study was to analyze the impact of both G-CSF withdrawal and the addition of primary prophylaxis with corticosteroids after ASCT. Methods Between January 2002 and August 2018, 111 MM patients conditioned with melphalan were managed at-home beginning +1 day after ASCT. Three groups were established: Group A (n = 33) received standard G-CSF post-ASCT; group B (n = 32) avoided G-CSF post-ASCT; group C (n = 46) avoided G-CSF yet added corticosteroid prophylaxis post-ASCT. Results The incidence of NF among the groups was reduced (64%, 44%, and 24%; P2 (OR 6.1; P = 0.002) and G-CSF avoidance plus corticosteroids (OR 0.1; P60 years (OR 14.6; P = 0.04) and G-CSF avoidance plus corticosteroids (OR 0.07; P = 0.05). Conclusions G-CSF avoidance and corticosteroid prophylaxis post ASCT minimize the incidence of NF in MM patients undergoing at-home ASCT. This approach should be explored in a prospective randomized clinical trial

The avoidance of G-CSF and the addition of prophylactic corticosteroids after autologous stem cell transplantation for multiple myeloma patients appeal for the at-home setting to reduce readmission for neutropenic fever

Autologous stem cell transplantation (ASCT) remains the standard of care for young multiple myeloma (MM) patients; indeed, at-home ASCT has been positioned as an appropriate therapeutic strategy. However, despite the use of prophylactic antibiotics, neutropenic fever (NF) and hospital readmissions continue to pose as the most important limitations in the outpatient setting. It is possible that the febrile episodes may have a non-infectious etiology, and engraftment syndrome could play a more significant role. The aim of this study was to analyze the impact of both G-CSF withdrawal and the addition of primary prophylaxis with corticosteroids after ASCT. Between January 2002 and August 2018, 111 MM patients conditioned with melphalan were managed at-home beginning +1 day after ASCT. Three groups were established: Group A (n = 33) received standard G-CSF post-ASCT; group B (n = 32) avoided G-CSF post-ASCT; group C (n = 46) avoided G-CSF yet added corticosteroid prophylaxis post-ASCT. The incidence of NF among the groups was reduced (64%, 44%, and 24%; P2 (OR 6.1; P = 0.002) and G-CSF avoidance plus corticosteroids (OR 0.1; P<0.001); and for hospital readmission: age �60 years (OR 14.6; P = 0.04) and G-CSF avoidance plus corticosteroids (OR 0.07; P = 0.05. G-CSF avoidance and corticosteroid prophylaxis post ASCT minimize the incidence of NF in MM patients undergoing at-home ASCT. This approach should be explored in a prospective randomized clinical trial

Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio