Noves troballes sobre diabetis tipus 2 a nivell cel·lular

Els autors d'aquest treball van analitzar una proteïna present en el teixit muscular: el transportador de glucosa 4 o GLUT4, molt important en la regulació dels nivells de glucosa de la sang. Les conclusions de l'estudi permeten conèixer amb més profunditat els mecanismes cel·lulars implicats en el desenvolupament de la diabetis tipus 2.Los autores de este trabajo analizaron una proteína presente en el tejido muscular: el transportador de glucosa 4 o GLUT4, de gran importancia en la regulación de los niveles de glucosa en la sangre. Las conclusiones del estudio permiten conocer con más profundidad los mecanismos celulares implicados en el desarrollo de la diabetes tipo 2

Vacunes per a peixos per administració oral

Actualment la major part del consum de peixos prové de l'aqüicultura. En aquest sentit, per millorar la condició de les espècies cultivades, el grup d'Immunologia evolutiva de la Unitat de Mecanismes de resposta a l'estrès i la malaltia de l'institut de Biotecnologia i Biomedicina (IBB- UAB) liderat per la Dra. Nerea Roher ha desenvolupat un format de vacuna oral per peixos d'interès comercial, en col·laboració amb el Instituto de Investigación y Formación Agraria y Pesquera (IFAPA) de Càdiz.Actualmente la mayor parte del consumo de peces proviene de la acuicultura. En este sentido, para mejorar la condición de las especies cultivadas, el grupo de Inmunología evolutiva de la Unidad de Mecanismos de respuesta al estrés y la enfermedad del Instituto de Biotecnologia y Biomedicina (IBB-UAB) liderado por la Dra. Nerea Roher ha desarrollado un formato de vacuna oral para peces de interés comercial, en colaboración con el Instituto de Investigación y Formación Agraria y Pesquera (IFAPA) de Cádiz

Interacció de la proteïna quinasa CK2 amb la xaperona GRP94 : implicacions funcionals /

Consultable des del TDXTítol obtingut de la portada digitalitzadaLa proteïna quinasa CK2 és una serina/treonina quinasa molt conservada i ubiqua en organismes eucariotes, implicada en diversos processos cel·lulars importants com proliferació o tumorigénesis. L'enzim de mamífers està format por dues subunitats catalítiques (a y/o a') y dues subunitats reguladores (b) encara que també s'ha descrit l'existència de subunitats catalítiques lliures. La regulació de l'activitat CK2 no és una regulació clàssica mitjançant segons missatgers o fosforilació, de fet la subunitat catalítica té activitat constitutiva. Es postula que la regulació es podria dur a terme per variació de la localització subcel·lular mitjançant interacció con proteïnes adscrites a compartiments subcel·lulares concrets. La proteïna xaperona grp94 (94 kDa-glucose regulated protein) és una proteïna d'estrès que pertany a la família de les hsp90 i que es localitza al Reticle Endoplásmic (RE) de totes les cèl·lules eucariotes. S'expressa constitutivament en condiciones normals y es sobreexpressa en situacions d'estrès com depleció de calci, inhibició de la glicosilació, infecció vírica, agents reductores etc. Utilitzant tècniques de Ressonància Plasmònica, Far Western y Pull down demostrem que el domini carboxi terminal de grp94 interacciona amb la subunitat catalítica de CK2 (CK2a) però no amb la subunitat reguladora ni amb l'holoenzim (a2b2). S'ha pogut mapejar la regió d'interacció entre ambdues proteïnes, utilizant diversos mutants de CK2a, així la regió s'ha delimitat a una regió de lisines (K74-77) molt conservada entre las CK2a de diferents espècies. D'altra banda s'ha demostrat que grp94 té activitat xaperona in vitro sobre CK2a i citrat sintasa (CS). Utilizant assajos d'agregació induïda por xoc tèrmic y tècniques de microscòpia electrònica s'ha determinat que grp94 es capaç d'inhibir l'agregación de CK2a i CS. L'activitat xaperona depén fortament de l'estat d'oligomerització de grp94, de forma que en condicions reductores en que grp94 perd la seva estructura quaternària, la capacitat d'inhibir agregació de proteïnes està disminuïda. S'ha estudiat també la distribució subcel·lular de CK2 i grp94 en un model animal de rates genèticament obeses (fa/fa). Aquestes rates són hiperinsulinèmiques i resistents a insulina degut a una down-regulation del receptor de insulina. S'había descrit en cèl·lules en cultiu que el tractament amb dosis altes d'insulina induïa la sínstesi de grp94. S'ha observat que no hi ha variació ni en els nivells ni en la distribució subcel·lular de grp94 però si hi ha variació tan en els nivells com en la distribució de CK2, que disminueix marcadament en citosol i augmenta en les fraccions membranoses.Protein kinase CK2 is a highly conserved and ubiquitously distributed serin/threonin kinase described in all eukaryotic organisms. CK2 has been implied in different cellular processes as proliferation or cancer. The mammalian enzyme is composed of two catalytic subunits (a and/or a') and two regulatory subunits (b), but have been described free catalytic and regulatory subunits. Regulation of CK2 is not a classic regulation through second messengers or phosphorylation, furthermore the catalytic subunit posses constitutive activity and it has been postulated that regulation could be done by changes in subcellular distribution due to interaction with different proteins from defined subcellular compartments. The protein chaperone grp94 (94 kDa-glucose regulated protein) belongs to the hsp90 family and is localized in the Endoplasmic Reticulum (ER) of all eukaryotic cells. Is constitutively expressed in absence of stress and is overexpressed under stress conditions as calcium depletion, virus infection, reducing agents etc. In the present work using techniques as Surface Plasmon Ressonance (SPR), Far Western and Pull down assays we have demonstrated that carboxy-terminal domain of grp94 interacts with the catalytic subunit of CK2 (CK2a) but not with the regulatory subunit or with the holoenzyme (a2b2). We mapped the interacting region using different mutants of CK2a, and we delimited the interacting domain to the cluster of lysines present in the helix aC(K74-77) on CK2a. This basic cluster is highly conserved in CK2a from different species but is not present in other kinases of the same family. Furthermore we demonstrated that grp94 has chaperone activity in vitro on CK2a and citrate synthase (CS). Light scattering of aggregated samples (aggregation promoted by heat shock) and electronic microscope imaging of aggregated samples have demonstrated that grp94 is able to protect CK2a and CS from aggregation. Chaperone activity depends on the maintenance of oligomeric state of grp94, then in reducing conditions when grp94 has lost its quaternary structure the ability to inhibit aggregation is diminished. In this work we also have been studied the subcellular distribution of CK2 and grp94 in an animal model of genetically obese rats (fa/fa). Zucker fa/fa rats are hyperinsulinemics and insulin resistant due to a down-regulation of insulin receptor. Additionally it has been described that in cultured cells insulin promoted the overexpression of grp94. In our model there is no variation of the levels or distribution of grp94 but exist differences in the levels and distribution of CK2 in liver of obese rats. In this rats CK2 is lower in the cytosolic fraction and increase in membranous fractions

Characterisation of PAMP/PRR interactions in European eel (Anguilla anguilla) macrophage-like primary cell cultures

The eel (Anguilla anguilla) has been identified as a vulnerable species with stocks dramatically declining over the past decade. In an effort to support the species from overfishing of wild stocks increased interest in eel aquaculture has been notable. In order to expand the scarce knowledge concerning the biology of this species significant research efforts are required in several fields of biology. The development of cell culture systems to study the immune response is a key step towards an increased understanding of the immune response and to develop resources to support further study in this threatened species. Macrophages are one of the most important effector cells of the innate immune system. The capacity to engulf pathogens and orchestrate the immune response relies on the existence of different surface receptors, such as scavenger receptors and toll-like receptors. We have developed and described an eel macrophage-like in vitro model and studied its functional and transcriptomic responses. Macrophagelike cells from both head kidney and purified peripheral blood leukocytes were obtained and phagocytic activity measured for different whole bacteria and yeast. Moreover, based on PAMP-PRR association the innate immune response of both head kidney and PBL derived macrophage-like cells was evaluated against different pathogen-associated molecular patterns (PAMPs). Results highlight that peptidoglycan stimulation strongly induces inflammatory mRNA expression reflected in the up-regulation of proinflammatory genes IL1b and IL18 in PBL derived cells whereas IL8 is upregulated in head kidney derived cells. Furthermore TLR2 mRNA abundance is regulated by all stimuli supporting a multifunctional role for this pathogen recognition receptor (PRR) in eel macrophage-like cells

Nanodelivery Systems as New Tools for Immunostimulant or Vaccine Administration : Targeting the Fish Immune System

Fish disease treatments have progressed significantly over the last few years and have moved from the massive use of antibiotics to the development of vaccines mainly based on inactivated bacteria. Today, the incorporation of immunostimulants and antigens into nanomaterials provide us with new tools to enhance the performance of immunostimulation. Nanoparticles are dispersions or solid particles designed with specific physical properties (size, surface charge, or loading capacity), which allow controlled delivery and therefore improved targeting and stimulation of the immune system. The use of these nanodelivery platforms in fish is in the initial steps of development. Here we review the advances in the application of nanoparticles to fish disease prevention including: the type of biomaterial, the type of immunostimulant or vaccine loaded into the nanoparticles, and how they target the fish immune system

A Novel Liposome-Based Nanocarrier Loaded with an LPS-dsRNA Cocktail for Fish Innate Immune System Stimulation

Development of novel systems of vaccine delivery is a growing demand of the aquaculture industry. Nano- and micro- encapsulation systems are promising tools to achieve efficient vaccines against orphan vaccine fish diseases. In this context, the use of liposomal based-nanocarriers has been poorly explored in fish; although liposomal nanocarriers have successfully been used in other species. Here, we report a new ~125 nm-in-diameter unilamellar liposome-encapsulated immunostimulant cocktail containing crude lipopolysaccharide (LPS) from E. coli and polyinosinic:polycytidylic acid [poly (I:C)], a synthetic analog of dsRNA virus, aiming to be used as a non-specific vaccine nanocarrier in different fish species. This liposomal carrier showed high encapsulation efficiencies and low toxicity not only in vitro using three different cellular models but also in vivo using zebrafish embryos and larvae. We showed that such liposomal LPS-dsRNA cocktail is able to enter into contact with zebrafish hepatocytes (ZFL cell line) and trout macrophage plasma membranes, being preferentially internalized through caveolae-dependent endocytosis, although clathrin-mediated endocytosis in ZFL cells and macropinocytocis in macrophages also contribute to liposome uptake. Importantly, we also demonstrated that this liposomal LPS-dsRNA cocktail elicits a specific pro-inflammatory and anti-viral response in both zebrafish hepatocytes and trout macrophages. The design of a unique delivery system with the ability to stimulate two potent innate immunity pathways virtually present in all fish species represents a completely new approach in fish health

Functional evidence for the inflammatory reflex in teleosts: A novel alpha7 nicotinic acetylcholine receptor modulates the macrophage response to dsRNA

The inflammatory reflex modulates the innate immune system, keeping in check the detrimental consequences of overstimulation. A key player controlling the inflammatory reflex is the alpha 7 acetylcholine receptor (α7nAChR). This receptor is one of the signalling molecules regulating cytokine expression in macrophages. In this study, we characterize a novel teleost α7nAChR. Protein sequence analysis shows a high degree of conservation with mammalian orthologs and trout α7nAChR has all the features and essential amino acids to form a fully functional receptor. We demonstrate that trout macrophages can bind α-bungarotoxin (α-BTX), a competitive antagonist for α7nAChRs. Moreover, nicotine stimulation produces a decrease in pro-inflammatory cytokine expression after stimulation with poly(I:C). These results suggest the presence of a functional α7nAChR in the macrophage plasma membrane. Further, in vivo injection of poly(I:C) induced an increase in serum ACh levels in rainbow trout. Our results manifest for the first time the functional conservation of the inflammatory reflex in teleosts

Polystyrene nanoplastics accumulate in ZFL cell lysosomes and in zebrafish larvae after acute exposure, inducing a synergistic immune response in vitro without affecting larval survival in vivo

Altres ajuts: pre-doctoral scholarship from UAB (2018FI_B_00711)The presence of small-sized plastic particles in marine and freshwater environments is a global problem but their long-term impact on ecosystems and human health is still far from being understood. Nanoplastics (<1000 nm) could pose a real and uncontrolled ecological challenge due to their smaller size and sharp ability to penetrate living organisms at any trophic level. Few studies evaluate the impact of nanoplastics in vivo on the immune system of aquatic organisms, while most of them assessed the impact on indirect markers of immune response such as regulation of gene expression, ROS production or DNA genotoxicity, among others. Moreover, the study of the effects of nanoplastics on aquatic vertebrate species in vivo is still scarce. In this context, we seek to shed light on the underlying effects of polystyrene nanoplastics (PS-NPs) on the immune response in a model fish species (Danio rerio, zebrafish) after an acute exposure, with a combination of in vitro and in vivo experiments. Our results show that PS-NPs (65 nm) are efficiently taken up by zebrafish liver cells, accumulating mainly in lysosomes. Furthermore, the expression of immune genes presents a synergy when cells were simultaneously exposed to PS-NPs, at a low dose and early time point (12 h) and challenged with a viral stimulus (poly(I:C)). Moreover, zebrafish larvae also internalize PS-NPs, accumulating them in the gut and pancreas. However, at concentrations of up to 50 mg l-1 in an acute exposure (48 h), PS-NPs do not interfere with the survival of the larvae after a lethal bacterial challenge (Aeromonas hydrophila). This study addresses the relevant environmental question of whether a living organism exposed to PS-NPs can cope with a real immune threat. We show that, although PS-NPs can induce an immune response, the survival of zebrafish larvae challenged with a bacterial infection after an acute exposure to PS-NP is not decimated with respect to unexposed larvae

Conseqüències fisiològiques d'una activació del sistema immunitari sobre la reproducció i el creixement en peixos d'interès en aqüicultura

En peixos teleostis, una activació del sistema immunitari comporta la producció de factors immunitaris que ajuden a combatre una infecció i estableixen una comunicació entre la resposta immunitària innata i l'adaptativa. A part d'aquesta funció estrictament immunitària, els factors immunitaris poden afectar el funcionament d'altres cèl·lules i teixits no immunitaris. Dos processos particularment importants, tant per l'estat biològic d'una població de peixos, com per aspectes més relacionats amb la productivitat d'espècies en cultiu, són la reproducció i el creixement. En aquest treball es descriuen estudis encaminats a investigar els efectes d'una activació del sistema immunitari, i dels factors produïts, sobre la reproducció i el creixement en peixos teleostis.In teleost fish, an activation of the immune system entails the production of immune factors that are key to fighting an infeccion and establish a bridge between the innate and D’aquesthe adaptive immune responses. In addition to this strictly immune function, immune factors can also affect the function of other non-immune cells and tissues. Reproduction and growth are two processes that are particularly important for the biological condition of a population of fish as well as for aspects more related to productivity of cultured species. In this paper, we describe studies designed to investigate the effects of an activation of the immune system, as well as of the factors produced, on reproduction and growth in teleost fish

Comparative analysis of the acute response of the trout, O. mykiss, head kidney to in vivo challenge with virulent and attenuated infectious hematopoietic necrosis virus and LPS-induced inflammation

Background: The response of the trout, O. mykiss, head kidney to bacterial lipopolysaccharide (LPS) or active and attenuated infectious hematopoietic necrosis virus (IHNV and attINHV respectively) intraperitoneal challenge, 24 and 72 hours post-injection, was investigated using a salmonid-specific cDNA microarray. Results: The head kidney response to i.p. LPS-induced inflammation in the first instance displays an initial stress reaction involving suppression of major cellular processes, including immune function, followed by a proliferative hematopoietic-type/biogenesis response 3 days after administration. The viral response at the early stage of infection highlights a suppression of hematopoietic and protein biosynthetic function and a stimulation of immune response. In fish infected with IHNV a loss of cellular function including signal transduction, cell cycle and transcriptional activity 72 hours after infection reflects the tissue-specific pathology of IHNV infection. attIHNV treatment on the other hand shows a similar pattern to native IHNV infection at 24 hours however at 72 hours a divergence from the viral response is seen and replace with a recovery response more similar to that observed for LPS is observed. Conclusion: In conclusion we have been able to identify and characterise by transcriptomic analysis two different types of responses to two distinct immune agents, a virus, IHNV and a bacterial cell wall component, LPS and a 'mixed' response to an attenuated IHNV. This type of analysis will lead to a greater understanding of the physiological response and the development of effective immune responses in salmonid fish to different pathogenic and pro-inflammatory agents