Analisi di stabilità di veicoli basculanti a tre ruote

Il Dipartimento di Ingegneria Civile e Industriale dell’Università di Pisa è partner del progetto europeo RESOLVE (Range of Electric SOlution for L-category VEhicles), avente come obiettivo lo sviluppo di motorizzazioni elettriche integrate, scalabili e modulari ad elevata efficienza energetica e costi contenuti da impiegare su una vasta gamma di veicoli di categoria L, comprese nuove formule di veicolo basculanti a tre/quattro ruote. Nei veicoli a più di due ruote sono presenti gradi di libertà aggiuntivi relativi al cinematismo di basculamento che condizionano la dinamica del veicolo, influenzando i modi propri e essi possono generare instabilità in determinate condizioni di marcia. In questo articolo viene presentata un’analisi numerica preliminare, in cui vengono studiati i modi propri di alcune architetture di veicoli a tre ruote attualmente in commercio, al fine di evidenziarne le differenze, con particolare riferimento al cinematismo anteriore. I modi propri di maggiore interesse sono quelli che caratterizzano anche i motocicli a 2 ruote, in particolare capsize, weave e wobble, le cui caratteristiche (parte reale ed parte immaginaria dell’autovalore) sono legate alla velocità di avanzamento e alla geometria del cinematismo utilizzato

Transforming growth factor-β-induced CUX1 isoforms are associated with fibrosis in systemic sclerosis lung fibroblasts

In the enhancer region of the human type I collagen alpha 2 (COL1A2) gene, we identified cis-elements for the transcription factor CUX1. However, the role of CUX1 in fibrosis remains unclear. Here we investigated the role of CUX1 in the regulation of COL1 expression and delineated the mechanisms underlying the regulation of COL1A2 expression by CUX1 in systemic sclerosis (SSc) lung fibroblasts. The binding of CUX1 to the COL1A2 enhancer region was assessed using electrophoretic mobility shift assays after treatment with transforming growth factor (TGF)-β. Subsequently, the protein expression levels of CUX1 isoforms were determined using Western blotting. Finally, the expression levels of COL1 and fibrosis-related cytokines, including CTGF, ET-1, Wnt1 and β-catenin were determined. The binding of CUX1 isoforms to the COL1A2 enhancer region increased after TGF-β treatment. TGF-β also increased the protein levels of the CUX1 isoforms p200, p150, p110, p75, p30 and p28. Moreover, SSc lung fibroblasts showed higher levels of CUX1 isoforms than normal lung fibroblasts, and treatment of SSc lung fibroblasts with a cathepsin L inhibitor (IW-CHO) decreased COL1 protein expression and reduced cell size, as measured using immunocytochemistry. In SSc and diffuse alveolar damage lung tissue sections, CUX1 localised within α-smooth muscle actin-positive cells. Our results suggested that CUX1 isoforms play vital roles in connective tissue deposition during wound repair and fibrosis

Age-dependent roles of peroxisomes in the hippocampus of a transgenic mouse model of Alzheimer’s disease

BACKGROUND: Alzheimer's Disease (AD) is a progressive neurodegenerative disease, especially affecting the hippocampus. Impairment of cognitive and memory functions is associated with amyloid beta-peptide-induced oxidative stress and alterations in lipid metabolism. In this scenario, the dual role of peroxisomes in producing and removing ROS, and their function in fatty acids beta-oxidation, may be critical. This work aims to investigating the possible involvement of peroxisomes in AD onset and progression, as studied in a transgenic mouse model, harboring the human Swedish familial AD mutation. We therefore characterized the peroxisomal population in the hippocampus, focusing on early, advanced, and late stages of the disease (3, 6, 9, 12, 18 months of age). Several peroxisome-related markers in transgenic and wild-type hippocampal formation were comparatively studied, by a combined molecular/immunohistochemical/ultrastructural approach. RESULTS: Our results demonstrate early and significant peroxisomal modifications in AD mice, compared to wild-type. Indeed, the peroxisomal membrane protein of 70 kDa and acyl-CoA oxidase 1 are induced at 3 months, possibly reflecting the need for efficient fatty acid beta-oxidation, as a compensatory response to mitochondrial dysfunction. The concomitant presence of oxidative damage markers and the altered expression of antioxidant enzymes argue for early oxidative stress in AD. During physiological and pathological brain aging, important changes in the expression of peroxisome-related proteins, also correlating with ongoing gliosis, occur in the hippocampus. These age- and genotype-based alterations, strongly dependent on the specific marker considered, indicate metabolic and/or numerical remodeling of peroxisomal population. CONCLUSIONS: Overall, our data support functional and biogenetic relationships linking peroxisomes to mitochondria and suggest peroxisomal proteins as biomarkers/therapeutic targets in pre-symptomatic AD

Evaluación del riesgo de inundación a múltiples componentes en la costa del Maresme

The coast is one of the areas most affected by natural hazards, with floods being the most frequent and significant of these in terms of their induced impacts, so any management scheme requires their evaluation. In coastal areas, flooding is a hazard associated with different processes acting at different scales: coastal storms, flash floods and sea level rise (SLR). To address the problem as a whole, this study presents a methodology to undertake a preliminary integrated risk assessment of the magnitude of each flood component, taking into account their scope (extension of the affected area) and their temporal scale. The risk is quantified using specific indicators to assess the hazard magnitude (for each component) and the consequences. This allows for a robust comparison of the spatial risk distribution along the coast in order to identify both the most at-risk areas and the most influential risk components. This methodology is applied to a stretch of coastline (Maresme, Catalonia) representative of the Spanish Mediterranean coast. The results obtained characterise this coastline as an area with a relatively low overall risk, although some hotspots are identified as having high-risk values. Resumen: La costa es una de las zonas más sometidas a riesgos naturales, siendo la inundación uno de los más frecuentes e importantes en términos de daños inducidos, por lo que cualquier esquema de gestión requiere evaluación. La inundación en zonas costeras es una amenaza natural asociada a diferentes procesos que actúan a distintas escalas: tormentas costeras, riadas y subida del nivel del mar (SNM). Para abarcar la totalidad del problema, este trabajo propone una metodología para la evaluación preliminar del riesgo integrado de inundación costera a una escala regional que permite evaluar la magnitud de cada componente teniendo en cuenta su alcance (extensión de la zona afectada) y su escala temporal. El riesgo se cuantifica en función de unos indicadores específicos que valoran la magnitud de la amenaza para cada componente y las consecuencias. Esto permite comparar robustamente la distribución espacial del riesgo a lo largo de la costa, para identificar tanto zonas de mayor riesgo como las componentes que más contribuyen al mismo. Aplicamos esta metodología a un tramo de costa característica del Mediterráneo español (Maresme, Cataluña). Los resultados permiten caracterizar esta costa como un área con un riesgo global relativamente bajo, pero algunos puntos singulares con riesgo alto

Cystatin D locates in the nucleus at sites of active transcription and modulates gene and protein expression

Cystatin D is an inhibitor of lysosomal and secreted cysteine proteases. Strikingly, cystatin D has been found to inhibit proliferation, migration, and invasion of colon carcinoma cells indicating tumor suppressor activity that is unrelated to protease inhibition. Here, we demonstrate that a proportion of cystatin D locates within the cell nucleus at specific transcriptionally active chromatin sites. Consistently, transcriptomic analysis show that cystatin D alters gene expression, including that of genes encoding transcription factors such as RUNX1, RUNX2, and MEF2C in HCT116 cells. In concordance with transcriptomic data, quantitative proteomic analysis identified 292 proteins differentially expressed in cystatin D-expressing cells involved in cell adhesion, cytoskeleton, and RNA synthesis and processing. Furthermore, using cytokine arrays we found that cystatin D reduces the secretion of several protumor cytokines such as fibroblast growth factor-4, CX3CL1/fractalkine, neurotrophin 4 oncostatin-M, pulmonary and activation-regulated chemokine/CCL18, and transforming growth factor B3. These results support an unanticipated role of cystatin D in the cell nucleus, controlling the transcription of specific genes involved in crucial cellular functions, which may mediate its protective action in colon cancer

Characterization of PTZ-Induced Seizure Susceptibility in a Down Syndrome Mouse Model That Overexpresses CSTB

Down syndrome (DS) is a complex genetic syndrome characterized by intellectual disability, dysmorphism and variable additional physiological traits. Current research progress has begun to decipher the neural mechanisms underlying cognitive impairment, leading to new therapeutic perspectives. Pentylenetetrazol (PTZ) has recently been found to have positive effects on learning and memory capacities of a DS mouse model and is foreseen to treat DS patients. But PTZ is also known to be a convulsant drug at higher dose and DS persons are more prone to epileptic seizures than the general population. This raises concerns over what long-term effects of treatment might be in the DS population. The cause of increased propensity for epilepsy in the DS population and which Hsa21 gene(s) are implicated remain unknown. Among Hsa21 candidate genes in epilepsy, CSTB, coding for the cystein protease inhibitor cystatin B, is involved in progressive myoclonus epilepsy and ataxia in both mice and human. Thus we aim to evaluate the effect of an increase in Cstb gene dosage on spontaneous epileptic activity and susceptibility to PTZ-induced seizure. To this end we generated a new mouse model trisomic for Cstb by homologous recombination. We verified that increasing copy number of Cstb from Trisomy (Ts) to Tetrasomy (Tt) was driving overexpression of the gene in the brain, we checked transgenic animals for presence of locomotor activity and electroencephalogram (EEG) abnormalities characteristic of myoclonic epilepsy and we tested if those animals were prone to PTZ-induced seizure. Overall, the results of the analysis shows that an increase in Cstb does not induce any spontaneous epileptic activity and neither increase or decrease the propensity of Ts and Tt mice to myoclonic seizures suggesting that Ctsb dosage should not interfere with PTZ-treatment

Structural basis for the recognition and cleavage of histone H3 by cathepsin L

Proteolysis of eukaryotic histone tails has emerged as an important factor in the modulation of cell-cycle progression and cellular differentiation. The recruitment of lysosomal cathepsin L to the nucleus where it mediates proteolysis of the mouse histone H3 tail has been described recently. Here, we report the three-dimensional crystal structures of a mature, inactive mutant of human cathepsin L alone and in complex with a peptide derived from histone H3. Canonical substrate–cathepsin L interactions are observed in the complex between the protease and the histone H3 peptide. Systematic analysis of the impact of posttranslational modifications at histone H3 on substrate selectivity suggests cathepsin L to be highly accommodating of all modified peptides. This is the first report of cathepsin L–histone H3 interaction and the first structural description of cathepsin L in complex with a substrate