Understanding the Influence of a Bifunctional Polyethylene Glycol Derivative in Protein Corona Formation around Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles are one of the most prominent agents used in theranostic applications, with MRI imaging the main application assessed. The biomolecular interface formed on the surface of a nanoparticle in a biological medium determines its behaviour in vitro and in vivo. In this study, we have compared the formation of the protein corona on highly monodisperse iron oxide nanoparticles with two different coatings, dimercaptosuccinic acid (DMSA), and after conjugation, with a bifunctional polyethylene glycol (PEG)-derived molecule (2000 Da) in the presence of Wistar rat plasma. The protein fingerprints around the nanoparticles were analysed in an extensive proteomic study. The results presented in this work indicate that the composition of the protein corona is very difficult to predict. Proteins from different functional categories—cell components, lipoproteins, complement, coagulation, immunoglobulins, enzymes and transport proteins—were identified in all samples with very small variability. Although both types of nanoparticles have similar amounts of bonded proteins, very slight differences in the composition of the corona might explain the variation observed in the uptake and biotransformation of these nanoparticles in Caco-2 and RAW 264.7 cells. Cytotoxicity was also studied using a standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Controlling nanoparticles’ reactivity to the biological environment by deciding on its surface functionalization may suggest new routes in the control of the biodistribution, biodegradation and clearance of multifunctional nanomedicines

Mecanismos moleculares implicados en el efecto protector de los polifenoles de la dieta frente al estrés oxidativo y la inflamación: estudio en células intestinales y animales de experimentación

El estrés oxidativo parece ser una de las causas implicadas en el origen de numerosas patologías y enfermedades intestinales. Los desequilibrios redox producidos en la mucosa intestinal pueden dar lugar a daños oxidativos y a una disfunción en las vías de señalización celular iniciando diversos procesos patológicos. En los últimos años la prevención nutricional de las enfermedades ha empezado a tomar una gran importancia. Así, ha surgido un gran interés por investigar los efectos biológicos de los compuestos bioactivos de los alimentos de la dieta frente al inicio y el desarrollo de diversas enfermedades. En concreto, se ha descrito que ciertos flavonoides pueden proteger frente al estrés oxidativo. Este efecto protector no solo se debe a su alta capacidad antioxidante, sino que además, los flavonoides pueden modular las vías de señales promoviendo toda una serie de efectos beneficiosos en las células que repercuten en los distintos órganos y en todo el organismo. El cacao y sus derivados como el chocolate son comúnmente consumidos en numerosos países y culturas de todo el mundo. Este producto, supone una importante fuente de procianidinas, un tipo de flavonoides de alto peso molecular y de limitada absorción intestinal. Sin embargo, a pesar de sus propiedades y de su amplia aceptación, hasta el momento son pocos los estudios que se han centrado en investigar los efectos de los flavonoides del cacao en el epitelio de la mucosa intestinal. De acuerdo con ello, este estudio se ha centrado en evaluar los mecanismos moleculares a través de los cuales los flavonoides del cacao pueden proteger frente al estrés oxidativo implicado en el inicio de las patologías intestinales. Con este fin, se han planteado los siguientes objetivos: 1.- Evaluar la efectividad de los flavonoides mayoritarios del cacao en la protección intestinal, utilizando dosis fisiológicas en un modelo de estrés oxidativo en las células intestinales de colon Caco-2. 2.- Estudiar los mecanismos moleculares de protección de los flavonoides del cacao frente al estrés oxidativo inducido por un tóxico alimentario en células intestinales Caco-2. 3.- Estudiar el potencial efecto protector de una dieta enriquecida en cacao frente al inicio del cáncer de colon en un modelo animal in vivo

SÄÄASEMAPALVELIN RASPBERRY PI:LLE

Opinnäytetyön tarkoituksena oli tehdä monipuolinen työ, jossa tulisi esille laajasti eri osa-alueita. Osaan meillä löytyi valmiina hyvä tuntemus mutta joistain osa-alueista emme tienneet paljoa. Tarkoituksena oli myös, että saisimme tehtyä työn josta olisi oikeasti jotain hyötyä. Halusimme työstä tarkoituksella monialaisen, jotta uuden oppiminen kuuluisi myös työhön. Opinnäytetyön tarkoituksena on tehdä toiminnallisesti omavarainen mahdollisimman automaattinen sääasema, joka toimii aurinkovoimmalla ja käyttää 3G-yhteyttä ottaakseen yhteyden web-palvelimeen, josta voidaan sitten havaita paikallinen sää. Monipuolinen työ mahdollistaa uuden oppimisen, jo opitun kertaamissta ja jo hallitun soveltamista. Opinnäytetyö toteutettiin itse soveltamalla. Hankitut laitteet ja palvelut on hankittu työn edetessä yksi kerralaan miettien aina niiden soveltuvuutta projektiin.The aim of the thesis was to create a comprehensive work that would include many different areas. We had a good knowledge of some of the areas but then nearly no knowledge of others. We wanted to create a work that would also be beneficial in some ways and contain many different areas so that learning would play a part. The aim of the thesis is to create an automatic weather station that would not re-quire human interaction in its daily work. The station would be powered by solar panel and connect to a remote web server using 3G-connection. A versatile work allowed the learning of new things. The repetition of old and knowledge in how to apply skills we already know. The equipment and services we use were bought and acquired one at a time during the progress of our thesis. The usability of every equipment was carefully thought out before purchase

Procyanidin B2 and a cocoa polyphenolic extract inhibit acrylamide-induced apoptosis in human Caco-2 cells by preventing oxidative stress and activation of JNK pathway

Humans are exposed to dietary acrylamide (AA) during their lifetime; it is therefore necessary to investigate the mechanisms associated with AA induced toxic effects. Accumulating evidence indicates that oxidative stress may contribute to AA cytotoxicity, but the link between oxidative stress and AA cytotoxicity in the gastrointestinal tract, the primary organ in contact with dietary AA, has not been described. In this study, we evaluate the alterations of the redox balance induced by AA in Caco-2 intestinal cells as well as the potential protective role of natural antioxidants such as a well-standardized cocoa polyphenolic extract (CPE) and its main polyphenol components epicatechin (EC) and procyanidin B2 (PB2). We found that AA-induced oxidative stress in Caco-2 cells is evidenced by glutathione (GSH) depletion and reactive oxygen species (ROS) overproduction. AA also activated the extracellular-regulated kinases and the c-Jun N-amino terminal kinases (JNKs) leading to an increase in caspase-3 activity and cell death. Studies with appropriate inhibitors confirmed the implication of oxidative stress and JNKs activation in AA-induced apoptosis. Additionally, AA cytotoxicity was counteracted by CPE or PB2 by inhibiting GSH consumption and ROS generation, increasing the levels of gamma-glutamyl cysteine synthase and glutathione-S-transferase and blocking the apoptotic pathways activated by AA. Therefore, AA-induced cytotoxicity and apoptosis are closely related to oxidative stress in Caco-2 cells. Interestingly, natural dietary antioxidant such as PB2 and CPE were able to suppress AA toxicity by improving the redox status of Caco-2 cells and by blocking the apoptotic pathway activated by AA

Comparative effects of dietary flavanols on antioxidant defences and their response to oxidant-induced stress on Caco2 cells

Flavanols are an important fraction of our diet both for their antioxidant capacity and because they are constituents of greatly accepted foodstuffs such as tea, wine and cocoa. In addition to their antioxidant activity by directly scavenging intracellular reactive oxygen species (ROS), flavanols have been recently shown to enhance protective enzymes. The objective was to evaluate the antioxidant response of colon-derived Caco2 cells to dietary flavanols