IL RUOLO DELL¿HUNTINGTINA NELLA FISIOLOGIA DEL DIFFERENZIAMENTO NEURONALE E NELLA PATOLOGIA

Huntingtin (htt) is the 3,144 amino acid protein whose mutation causes Huntington\u2019s disease (HD). Mutant htt is toxic for brain neurons, but the mechanism leading to pathology is still far from being understood. Moreover, since loss of wild type (WT) htt contributes to pathogenesis, the study of htt\u2019s role and the effect of its depletion, in the central nervous system becomes important. In this Thesis we analyse complementarily the role of WT and mutant htt in physiological and pathological conditions. In the first part, it is described a novel role of WT htt during neural development. This field is still quite unexplored, and, even if the function of protein has been largely described during post-natal life (when HD onset occurs), there are recent evidences that also normal development could be altered in htt depletion condition. Specifically it has been investigated the role of htt in establishment and maintenance of neuroepithelial apico-basal polarity and, as a result, in the regulation of neural progenitors cell fate decision. We demonstrate that htt, through cooperation with polarity protein aPKC, contributes to regulation of polarity mechanism during early neurogenesis. In the second part of the Thesis it is described the establishment of a human in vitro model of HD, thanks to somatic cell reprogramming technology. We report the generation of a series of induced pluripotent stem (iPS) cells derived from several patients. HD-iPS cells have the potential to be differentiated to the neuronal population that degenerate during disease progression, holding the identical genetic information of the donor. Starting also from rare homozygous patient, and demonstrating mutation related enhanced lysosomal activity, our work is the first that describes a cohort of HD-iPS cells and their phenotypical characterization

prediction of mean and turbulent kinetic energy in rectangular shallow reservoirs

AbstractShallow rectangular reservoirs are common structures in urban hydraulics and river engineering. Despite their simple geometries, complex symmetric and asymmetric flow fields develop in such reservoirs, depending on their expansion ratio and length-to-width ratio. The original contribution of this study is the analysis of the kinetic energy content of the mean flow, based on UVP velocity measurements carried throughout the reservoir in eleven different geometric configurations. A new relationship is derived between the specific mean kinetic energy and the reservoir shape factor. For most considered geometric configurations, leading to four different flow patterns, the experimentally observed flow fields and mean kinetic energy contents are successfully reproduced by an operational numerical model based on the depth-averaged flow equations and a two-length-scale k- turbulence closure. The analysis also highlights the better performance of this depth-averaged k- model compared to an algebraic turbu..

2D versus 3D human induced pluripotent stem cell-derived cultures for neurodegenerative disease modelling

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS), affect millions of people every year and so far, there are no therapeutic cures available. Even though animal and histological models have been of great aid in understanding disease mechanisms and identifying possible therapeutic strategies, in order to find disease-modifying solutions there is still a critical need for systems that can provide more predictive and physiologically relevant results. One possible avenue is the development of patient-derived models, e.g. by reprogramming patient somatic cells into human induced pluripotent stem cells (hiPSCs), which can then be differentiated into any cell type for modelling. These systems contain key genetic information from the donors, and therefore have enormous potential as tools in the investigation of pathological mechanisms underlying disease phenotype, and progression, as well as in drug testing platforms. hiPSCs have been widely cultured in 2D systems, but in order to mimic human brain complexity, 3D models have been proposed as a more advanced alternative. This review will focus on the use of patient-derived hiPSCs to model AD, PD, HD and ALS. In brief, we will cover the available stem cells, types of 2D and 3D culture systems, existing models for neurodegenerative diseases, obstacles to model these diseases in vitro, and current perspectives in the field

"Contributo delle Tecniche di <<Imaging>> nello Studio dell'Evoluzione degli Innesti Massivi"

Contributo delle Tecniche di > nello Studio dell'Evoluzione degli Innesti Massi

Neuropotent self-renewing neural stem (NS) cells derived from mouse induced pluripotent stem (iPS) cells

Neural stem (NS) cells are a homogenous population of stem cells that expands in monolayer under serum-free conditions while remaining highly neuropotent. Here, we generated NS cells from induced pluripotent stem (iPS) cells that were previously derived from mouse fibroblasts (NS-(f)iPS). We showed that NS-(f)iPS cells exhibit long-term expansion and express markers of neurogenic radial glia. Analyses of the regional markers expressed in NS-(f)iPS cells suggested a ventral-rhombencephalic identity. Upon exposure to differentiation protocols, NS-(f)iPS cells produce neurons, astrocytes, and oligodendrocytes with an efficiency similar to ES-derived NS cells. NS-(f)iPS cells represent a new tool for studying neural cell fate determination and terminal differentiation, providing an interesting resource for experimental transplantation. Comparative studies between NS cells derived from iPS cells, reprogrammed from different somatic sources, and from authentic ES cells are necessary to identify critical elements for multipotency acquisition

Coupling between flow and sediment deposition in rectangular shallow reservoirs

Flow velocity and sedimentation patterns were investigated experimentally and numerically in shallow rectangular reservoirs with different asymmetric locations of the inlet and outlet channels. Velocity fields were measured in the entire reservoir, both for clear water flow and with suspended sediments. Thickness of sediment deposits were mapped in the whole reservoir by means of a laser light method. In one of the studied geometric configurations, injection of suspended sediments led to a complete change in the observed flow field. Experimental results were compared with numerical simulations performed with the depth-averaged flow model WOLF 2D, using a depth-averaged k-e turbulence model. The simulations lead to accurate predictions of the velocity profiles and the change in flow pattern as a result of sediment deposits was successfully reproduced