Single-step green synthesis and characterization of gold-conjugated polyphenol nanoparticles with antioxidant and biological activities

Background: Gold nanoparticles (GNPs) are likely to provide an attractive platform for combining a variety of biophysicochemical properties into a unified nanodevice with great therapeutic potential. In this study we investigated the capabilities of three different natural polyphenols, epigallocatechin-3-gallate (EGCG), resveratrol (RSV), and fisetin (FS), to allow synergistic chemical reduction of gold salts to GNPs and stabilization in a single-step green process. Moreover, antioxidant properties of the nanosystems, as well as preliminary antiproliferative activity and apoptotic process investigation of model EGCG-GNPs on stable clones of neuroblastoma SH-SY5Y cells expressing CFP-DEVD-YFP reporter, were examined. Methods: The GNPs were characterized by physicochemical techniques, polyphenol content, and in vitro stability. The antioxidant activity of the GNPs was also determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation (ABTS) radical-scavenging assays. Stable clones of neuronal SH-SY5Y-CFP-DEVD-YFP were generated and characterized, and cell viability after treatment with EGCG-GNPs was assessed after 72 hours through a 3(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Activation of the apoptotic pathways was also investigated by Western blot analysis. Results: With a diameter in the size range of 10–25 nm, the obtained nanoparticles (NPs) were found to contain 2.71%, 3.23%, and 5.47% of EGCG, RSV, and FS, respectively. Nanoprototypes exhibited remarkable in vitro stability in various media, suggesting that NP surface coating with phytochemicals prevents aggregation in different simulated physiological conditions. The scavenging activities for DPPH and ABTS were highly correlated with EGCG, RSV, and FS content. Moreover, high correlation coefficients between the ABTS and DPPH values were found for the prepared nanosystems. EGCG-GNPs induce a dose-dependent reduction on SH-SY5Y-CFP-DEVD-YFP cell viability that is likely to involve the activation of the apoptotic pathways, similarly to free EGCG, as suggested by the processing of the CFP-DEVD-YFP reporter. Conclusion: These results prompted us to propose the ecofriendly synthesized EGCG-, RSV-, and FS-based nanogold conjugates as suitable carriers for bioactive polyphenols to be used for the treatment of disorders associated with oxidative stress, including neurodegenerative disorders, cardiovascular disease, and cancer.</br

Emergency Department as an epidemiological observatory of Human Mobility: the experience of the Moroccan population

We conducted a retrospective study of the accesses to the Emergency Department registered from January 2000 to December 2014 in 5 major hospitals in the Metropolitan Area of Rome. We extrapolated data relating to patients of Moroccan origin from about 5 million total accesses, so we compared with Italians data which, in the same period, came to ED. The Moroccan population is distinguished by a larger number of diagnoses belonging to the ICD-9 code of Infectious Diseases and, more precisely, to Respiratory Infectious Diseases. There are also no differences in the assignment of such diagnoses to Moroccans with Italian citizenship, and this led to think that this could play an important role in the use of the ED and moreover that enrollment to the National Health Service may reduce its inappropriate use. Regarding to Degenerative Disorders, the result of our analysis is quite emblematic, showing that the accesses to the ED is due to Cardiovascular Diseases: 6.33% of Italians' accesses against 1.81% of Moroccans and 2.36% of Moroccans with Italian citizenship. The main explanation for this difference is, obviously, due to the age of the population: about 60% of Moroccans who accessed to ED was less than 40 years old. It is interesting how, in the field of ​​Cardiovascular Diseases, Moroccans have a lower percentage of diagnosis compared to Italians for acute diseases and a greater percentage of diagnoses for chronic diseases, suggesting once again that accesses to ED for migrants often is due to the inability to use the general services of the National Health Service. In conclusion, from the point of view of the Emergency Department, Migration Medicine still has Infectious Diseases as the main reason for access. Degenerative Disorders remain a prerogative of the Italians, but we could certainly assume that the Moroccan population would develop at some point with the aging

Simultaneous absence of dopamine D1 and D2 receptor-mediated signaling is lethal in mice

Dopamine (DA) controls a wide variety of physiological functions in the central nervous system as well as in the neuroendocrine and gastrointestinal systems. DA signaling is mediated by five cloned receptors named D1-D5. Knockout mouse models for the five receptors have been generated, and, albeit impaired for some important DA-mediated functions, they are viable and can reproduce. D1 and D2 receptors are the most abundant and widely expressed DA receptors. Cooperative/synergistic effects mediated by these receptors have been suggested, in particular, in the control of motor behaviors. To analyze the extent of such interrelationship, we have generated double D1/D2 receptor mutants. Interestingly, in contrast to single knockouts, we found that concurrent ablation of the D1 and D2 receptors is lethal during the second or third week after birth. This dramatic phenotype is likely to be related to altered feeding behavior and dysfunction of the gastrointestinal system, especially because major anatomical changes were not identified in the brain. Similarly, in the absence of functional D1, heterozygous D2 mutants (D1r -/-;D2r +/-) showed severe growth retardation and did not survive their postweaning period. The analysis of motor behavior in D1r/D2r compound mutants showed that loss of D2-mediated functions reduces motor abilities, whereas the effect of D1r ablation on locomotion strongly depends on the experimental paradigms used. These studies highlight the interrelationship between D1 and D2 receptor-mediated control of motor activity, food intake, and gastrointestinal functions, which has been elusive in the single-gene ablation studies

Astroglial Inhibition of NF-κB Does Not Ameliorate Disease Onset and Progression in a Mouse Model for Amyotrophic Lateral Sclerosis (ALS)

Motor neuron death in amyotrophic lateral sclerosis (ALS) is considered a “non-cell autonomous” process, with astrocytes playing a critical role in disease progression. Glial cells are activated early in transgenic mice expressing mutant SOD1, suggesting that neuroinflammation has a relevant role in the cascade of events that trigger the death of motor neurons. An inflammatory cascade including COX2 expression, secretion of cytokines and release of NO from astrocytes may descend from activation of a NF-κB-mediated pathway observed in astrocytes from ALS patients and in experimental models. We have attempted rescue of transgenic mutant SOD1 mice through the inhibition of the NF-κB pathway selectively in astrocytes. Here we show that despite efficient inhibition of this major pathway, double transgenic mice expressing the mutant SOD1G93A ubiquitously and the dominant negative form of IκBα (IκBαAA) in astrocytes under control of the GFAP promoter show no benefit in terms of onset and progression of disease. Our data indicate that motor neuron death in ALS cannot be prevented by inhibition of a single inflammatory pathway because alternative pathways are activated in the presence of a persistent toxic stimulus

Etude de l'épissage et de la signalisation du récepteur dopaminergique de type D2

Le récepteur dopaminergique D2 est exprimé principalement dans le système nerveux central et l'hypophyse; il est implique dans une série de fonctions vitales allant du contrôle de la locomotion jusqu'à la régulation hormonale. L'altération de l'expression de ce récepteur pourrait être à l'origine de plusieurs pathologies humaines telles que la maladie de Parkinson, la schizophrénie, et les tumeurs hypophysaires. Il existe deux isoformes du récepteur D2 (D2R) produites par épissage alternatif du même transcrit. L'isoforme longue (D2L) est prédominante dans le striatum et l'hypophyse, alors qu'elle est moins abondante que l'isoforme courte dans la substance noire et les tubercules olfactifs. L'isoforme longue diffère de l'isoforme courte par la présence du sixième exon. Cet exon code 29 aminoacides qui constituent une partie de la troisième boucle intra-cytoplasmique du D2R. Il a été montré que cette boucle est impliquée dans l'interaction avec les protéines G, et que D2L et D2S ont une affinité différente pour les protéines G. Dans le laboratoire d'E.Borrelli une lignée de souris Knock Out pour le récepteur D2 a été générée. Ces souris ont un phénotype caractérisé par des problèmes de posture ainsi que des tremblements. La locomotion des souris KO est fortement diminuée par rapport aux souris sauvages. Les souris D2 KO manifestent de faibles performances dans le test de rotarod qui mesure la capacité de coordination du mouvement des animaux. L'ensemble de ces phénotypes suggère une ressemblance avec la maladie de Parkinson. De plus les souris femelles KO développent des tumeurs hypophysaire due à la prolifération des lactotropes conduisant finalement à la formation de prolactinomes. Durant ma thèse j'ai essayé d'approcher différents aspects des fonctions des D2R. Il a été montré que les deux isoformes ont des fonctions différentes in vivo dans le système nerveux central. Grâce à un modèle de souris n'exprimant que l'isoforme D2S sans réduction du niveau total de l'ARNm du D2R des expériences faites au laboratoire d'E. Borrelli ont démontré que D2L est principalement impliqué dans la sortie motrice du système dopaminergique alors que D2S contrôle principalement l'activité électrique et la libération de dopamine des neurones dopaminergiques. Dans la première partie de ma thèse j'ai étudié le rôle des différents isoformes du D2R dans la physiologie de l'hypophyse. L'hypophyse est composée de cinq types cellulaires différents : lactotropes, somatotropes, tyrotropes, corticotropes et mélanotropes. Chaque type cellulaire est caractérisé par la sécrétion d'une ou plusieurs hormones trophiques qui régulent un éventail divers de processus biologiques importants en réponse à des signaux de l'hypothalamus et des organes périphériques.The neurotransmitter dopamine (DA) is the most abundant catecolamine in the central nervous system (CNS) where it is implicated in a variety of physiological functions including motor control, sexual behaviour and cognition. In parallel to its functions in the central nervous system, DA also exerts an inhibitory neuroendocrine control of hormone synthesis and release as well as cell proliferation in the pituitary gland. D2Rs exist in two different isoforms originated by alternative splicing of the same transcript. The long isoform (D2L) is predominant in the striatum and pituitary gland, whereas it is less abundant than the short isoform in the substantia nigra and the olfactory tubercle. The long isoform differs from the short isoform in the presence of the sixth exon. This exon codes for 29 amino acids that constitute part of the third intracellular loop of the D2R. It has been shown that such loop is involved in the interaction with G-proteins as well as that D2L and D2S preferentially bind different G-proteins. In Borrelli laboratory a mouse line knock-out for the receptor D2 has been generated. These mice show a phenotype characterized by posture problems and tremors. Knock-out mice move less than WT and show low performance in the rota-rod test that measure the ability of coordination of the animals. Indeed the knock-out mice phenotype strongly rassembles to the Parkinson desease. Furthermore female knock-out mice develop pituitary hyperlasia due to lactotrop proliferation than finally leads to prolactinomas formation. During my thesis I tried to approch different aspects of D2R fuctions.. It has been have shown that the two D2R isoforms have different function in vivo in the central neurosystem. Using a mouse line which expresses only the D2S isoform without a decrease in the total level of D2R mRNA Borrelli laboratory has demonstrated that D2L is more deeply implicated in motor out-put of the dopaminergic system while D2S mainly controls the firing and dopamine release of dopaminergic neurones. In the first part of my thesis I studied the role of the different D2R isoforms in the pituitary gland physiology. The pituitary gland is composed of five different cellular types: lactotrops, somatotrps, tyrotrops, corticotrops and melanotrops. Each cellular type is characterized by the secretion of one or more trophic hormones that regulate a diverse range of important biological processes in response to signals from the hypothalamus and peripheral organs. The D2R is expressed in only in lactotrops in anterior lobe and melanotrops in intermediate lobe. We generated two transgenic lines expressing the long or the short isoform of the receptor specifically in the pituitary.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF