It takes two to remyelinate: A bioengineered platform to study astrocyte-oligodendrocyte crosstalk and potential therapeutic targets in remyelination

The loss of the myelin sheath insulating axons is the hallmark of demyelinating diseases. These pathologies often lead to irreversible neurological impairment and patient disability. No effective therapies are currently available to promote remyelination. Several elements contribute to the inadequacy of remyelination, thus understanding the intricacies of the cellular and signaling microenvironment of the remyelination niche might help us to devise better strategies to enhance remyelination. Here, using a new in vitro rapid myelinating artificial axon system based on engineered microfibres, we investigated how reactive astrocytes influence oligodendrocyte (OL) differentiation and myelination ability. This artificial axon culture system enables the effective uncoupling of molecular cues from the biophysical properties of the axons, allowing the detailed study of the astrocyte-OL crosstalk. Oligodendrocyte precursor cells (OPCs) were cultured on poly(trimethylene carbonate-co-ε-caprolactone) copolymer electrospun microfibres that served as surrogate axons. This platform was then combined with a previously established tissue engineered glial scar model of astrocytes embedded in 1 % (w/v) alginate matrices, in which astrocyte reactive phenotype was acquired using meningeal fibroblast conditioned medium. OPCs were shown to adhere to uncoated engineered microfibres and differentiate into myelinating OL. Reactive astrocytes were found to significantly impair OL differentiation ability, after six and eight days in a co-culture system. Differentiation impairment was seen to be correlated with astrocytic miRNA release through exosomes. We found significantly reduction on the expression of pro-myelinating miRNAs (miR-219 and miR-338) and an increase in anti-myelinating miRNA (miR-125a-3p) content between reactive and quiescent astrocytes. Additionally, we show that OPC differentiation inhibition could be reverted by rescuing the activated astrocytic phenotype with ibuprofen, a chemical inhibitor of the small rhoGTPase RhoA. Overall, these findings show that modulating astrocytic function might be an interesting therapeutic avenue for demyelinating diseases. The use of these engineered microfibres as an artificial axon culture system will enable the screening for potential therapeutic agents that promote OL differentiation and myelination while providing valuable insight on the myelination/remyelination processes

Ana Relvas Pires, Les femmes dans la conversion de la Scandinavie, (VIIIe - début XIIe siècle)

L’étude proposée examine les rapports entre la Scandinavie et l’Europe au Haut Moyen Âge sous un nouvel angle, à savoir le rôle et la place des femmes dans la conversion des peuples scandinaves et la christianisation de leurs territoires respectifs (Danemark, Norvège et Suède, ainsi que les zones de peuplement scandinave de Normandie, Angleterre, Shetland, Orcades, Hébrides, Féroé, Irlande et Islande). Les travaux, entre autres, de A.-S. Gräslund et de B. Sawyer sur les femmes scandinaves et ..

Ana Relvas Pires, Les femmes dans la conversion de la Scandinavie, (VIIIe - début XIIe siècle)

L’étude proposée examine les rapports entre la Scandinavie et l’Europe au Haut Moyen Âge sous un nouvel angle, à savoir le rôle et la place des femmes dans la conversion des peuples scandinaves et la christianisation de leurs territoires respectifs (Danemark, Norvège et Suède, ainsi que les zones de peuplement scandinave de Normandie, Angleterre, Shetland, Orcades, Hébrides, Féroé, Irlande et Islande). Les travaux, entre autres, de A.-S. Gräslund et de B. Sawyer sur les femmes scandinaves et ..

Ana Relvas Pires, Les femmes dans la conversion de la Scandinavie, (VIIIe - début XIIe siècle)

L’étude proposée examine les rapports entre la Scandinavie et l’Europe au Haut Moyen Âge sous un nouvel angle, à savoir le rôle et la place des femmes dans la conversion des peuples scandinaves et la christianisation de leurs territoires respectifs (Danemark, Norvège et Suède, ainsi que les zones de peuplement scandinave de Normandie, Angleterre, Shetland, Orcades, Hébrides, Féroé, Irlande et Islande). Les travaux, entre autres, de A.-S. Gräslund et de B. Sawyer sur les femmes scandinaves et ..

Subsídios para a joalharia contemporânea em Portugal

Para se efectuar a investigação sobre a joalharia portuguesa contemporânea, a partir de 1950, procedeu-se ao seu enquadramento histórico e geográfico. À semelhança do que se verificava resto do mundo, constata-se uma interdisciplinaridade com as restantes artes plásticas (em especial com o design). E consequente alteração das formas, materiais e técnicas anteriormente usadas. Também ao nível da função da jóia se observaram alterações. Foi, então, estudada a relação da joia com o corpo. Portugal conta com um conjunto de artistas joalheiros em plena produção. Existem estruturas de ensino e profissionais, sem, contudo, haver um museu de joalharia contemporânea. Mesmo assim, é de notar o elevado número de exposições e projectos relacionados com esta temática. Neste panorama, surge uma joalharia contemporânea liberta de uma identidade, que permite que o trabalho de cada artista seja singular, sem obedecer a regras limitativas ou castradoras da criatividade. /ABSTRACT: It was during the 50s that in order to carry out the research on the contemporary portuguese jewellery, one had to establish its historical and geographical approach. As it happened in the rest of the world, one may say there was an interdisciplinary with the other fine arts (specially with the design) and the consequent change in the shapes, materials and techniques previously used. The jewel was not an exception to these changes as far its function is concerned. Due to these factors, the relationship between the jewel and the body started to be studied. Nowadays Portugal counts a set of jewelers in full production. There are specialized schools in this area as well as professionals although there isn't a museum of contemporary jeweler. ln spite of this, a huge number of exhibitions and projects concerning this area, take place in Portugal. Taking all these aspects into consideration, a free contemporary jewelry is emerging, allowing the work of each artist may be unique without obeying to any strict or limitative rules that could work as a barrier to their creativity