INTERAZIONE CALCIUM-SENSING RECEPTOR-FILAMINA A E CARATTERIZZAZIONE DEL PATHWAY DI TRASDUZIONE DEL SEGNALE

Background: Calcium sensing receptor (CaSR) is a seven-transmembrane domains G-protein coupled receptor, with a large extracellular domain and a intracellular tail. It is important for maintaining the calcium steady state. In fact, it is able to detect variations in the extracellular calcium concentration ([Ca2+]o) and to activate a complex signal transduction pathway that causes increase of intracellular levels of inositol 1,4,5-trisphosphate (IP3) and calcium, activation of PKC and of MAPK cascade. The MAPK activation requires CaSR interaction with the scaffold protein Filamin A (FLNA). Just inside the binding region with the FLNA there is a polymorphism of the receptor tail, R990G, that induces a gain of function in the activity of the receptor, increasing the sensitivity to the calcimimetic R-568 and inducing different signal propagation compared to the WT CaSR. Moreover, both CaSR and FLNA are involved in tumors of the parathyroid glands and it has been demonstrated that CaSR activity is down-regulated in these tumors. The aim of this thesis is to confirm the hypothesis that the wild-type and polymorphic CaSR follow two different signal transduction pathways and to investigate the involvement of FLNA in this process. Therefore, we investigate the interaction CaSR-FLNA in parathyroid adenomas and carcinomas. Materials and Methods: FLNA was silenced with a Short interfering RNA in renal embryonic HEK-293 cells transfected with WT or polymorphic CaSR. The CaSR activity was assessed by measuring the activity of ERK 1/2 by Western blot. The expression of FLNA and CaSR were evaluated by immunofluorescence in HEK-293 cells and by immunofluorescence and immunohistochemistry in parathyroid adenomas and carcinomas. CaSR and FLNA mRNA levels were measured with Real-Time PCR in HEK-293 cells and in 30 parathyroid adenomas; parathyroid adenomas of the same samples were genotyped for the SNP R990G using the technique Taqman genotyping assay. Results: Western Blot data showed a decrease of expression and activity in both forms of the receptor (WT CaSR and R990G CaSR) in the absence of FLNA. Real-Time results of HEK-293 cells show a decrease of mRNA expression in both WT CaSR (0.55\ub10.23 vs 1.56\ub1 0.80, p-value=0.07) that R990G CaSR (0.51\ub10.37 vs 1.82\ub11.43, p-value=0.41) in the absence of FLNA compared to the control. The presence of the calcimimetic R-568 seems to mask the differences in the absence of FLNA, keeping the gain of function of R990G CaSR. The CaSR and FLNA resulted down-regulated in parathyroid glands tumors. Immunohistochemistry of parathyroid adenomas and carcinomas showed a decrease of FLNA expression related to the degree of tumor malignancy. Furthermore, the correlation between CaSR and FLNA mRNA levels and R990G SNP in 30 adenomas showed a significant rise of mRNA expression of both CaSR type (n=28 AA, 1.07\ub10.97; n=2 AG, 3.39\ub11.16, p-value=0.003) and FLNA (n=28 AA, 0.14\ub10.08; n=2 AG, 3.35\ub10.09, p-value=0.002) in the presence of the heterozygous genotype AG. Conclusion: this study has allowed us to show that FLNA is required for the CaSR-inducted stimulation of ERK1/2 activity, both in WT CaSR and R990G CaSR. So we could hypothesize that the gain of function of the CaSR R990G could be due to a stronger interaction with FLNA, induced by non-conservative polymorphism in the binding region for FLNA. Furthermore, we can conclude that the CaSR and FLNA interaction is also crucial in parathyroid tumors, in which we demonstrated a positive correlation of two proteins expression, both down-regulated in tumors. The correlation of FLNA and CaSR mRNA expression with R990G polymorphism showed the increase of both proteins expression in the presence of the polymorphic variant, suggesting a protective role in the parathyroid glands tumors, with unknown mechanism

Curcumin and type 2 diabetes mellitus : Prevention and treatment

Type 2 diabetes mellitus (T2DM) is an ensemble of metabolic diseases that has reached pandemic dimensions all over the world. The multifactorial nature of the pathology makes patient management, which includes lifelong drug therapy and lifestyle modification, extremely challenging. It is well known that T2DM is a preventable disease, therefore lowering the incidence of new T2DM cases could be a key strategy to reduce the global impact of diabetes. Currently, there is growing evidence on the efficacy of the use of medicinal plants supplements for T2DM prevention and management. Among these medicinal plants, curcumin is gaining a growing interest in the scientific community. Curcumin is a bioactive molecule present in the rhizome of the Curcuma longa plant, also known as turmeric. Curcumin has different pharmacological and biological effects that have been described by both in vitro and in vivo studies, and include antioxidant, cardio-protective, anti-inflammatory, anti-microbial, nephro-protective, anti-neoplastic, hepato-protective, immunomodulatory, hypoglycaemic and anti-rheumatic effects. In animal models, curcumin extract delays diabetes development, improves \u3b2-cell functions, prevents \u3b2-cell death, and decreases insulin resistance. The present review focuses on pre-clinical and clinical trials on curcumin supplementation in T2DM and discusses the peculiar mechanisms by which curcumin might ameliorate diabetes management

Alkali-Activated Red Mud and Construction and Demolition Waste-Based Components: Characterization and Environmental Assessment

The aluminum Bayer production process is the most diffused process in the world, but it creates a high amount of basic waste material known as red mud (RM). The use of RM as a precursor of alkali-activated materials is one of the best opportunities for both the ecosystem and the economy. In the present work, mortar samples were obtained by alkali activation of RM with various percentages of blast-furnace slag (BFS) and inert construction and demolition sands. This process creates samples that have a low environmental impact and that can be used as an alternative in the construction industry to cement materials or ceramic ones. The development of these new materials could also represent a way to reduce the CO2 emissions linked to cement and ceramic brick production. In the present study, cubic 40 mm samples reported very interesting values in compressive strength, with a maximum of about 70 MPa for low environmental impact mortars. With such a material, it is possible to create solid bricks for structural use and concrete tiles for road paving or use it for other purposes. Mortar specimens were prepared and characterized, and an LCA analysis with a “cradle-to-gate” approach was carried out for a comparison of the environmental impact of the studied mortars with other materials currently marketed

Riesz potentials and nonlinear parabolic equations

The spatial gradient of solutions to nonlinear degenerate parabolic equations can be pointwise estimated by the caloric Riesz potential of the right hand side datum, exactly as in the case of the heat equation. Heat kernels type estimates persist in the nonlinear cas

An Innovative Lipidomic Workflow to Investigate the Lipid Profile in a Cystic Fibrosis Cell Line

Altered lipid metabolism has been associated to cystic fibrosis disease, which is characterized by chronic lung inflammation and various organs dysfunction. Here, we present the validation of an untargeted lipidomics approach based on high-resolution mass spectrometry aimed at identifying those lipid species that unequivocally sign CF pathophysiology. Of n.13375 mass spectra recorded on cystic fibrosis bronchial epithelial airways epithelial cells IB3, n.7787 presented the MS/MS data, and, after software and manual validation, the final number of annotated lipids was restricted to n.1159. On these lipids, univariate and multivariate statistical approaches were employed in order to select relevant lipids for cellular phenotype discrimination between cystic fibrosis and HBE healthy cells. In cystic fibrosis IB3 cells, a pervasive alteration in the lipid metabolism revealed changes in the classes of ether-linked phospholipids, cholesterol esters, and glycosylated sphingolipids. Through functions association, it was evidenced that lipids variation involves the moiety implicated in membrane composition, endoplasmic reticulum, mitochondria compartments, and chemical and biophysical lipids properties. This study provides a new perspective in understanding the pathogenesis of cystic fibrosis and strengthens the need to use a validated mass spectrometry-based lipidomics approach for the discovery of potential biomarkers and perturbed metabolism

Multi-species mean-field spin-glasses. Rigorous results

We study a multi-species spin glass system where the density of each species is kept fixed at increasing volumes. The model reduces to the Sherrington-Kirkpatrick one for the single species case. The existence of the thermodynamic limit is proved for all densities values under a convexity condition on the interaction. The thermodynamic properties of the model are investigated and the annealed, the replica symmetric and the replica symmetry breaking bounds are proved using Guerra's scheme. The annealed approximation is proved to be exact under a high temperature condition. We show that the replica symmetric solution has negative entropy at low temperatures. We study the properties of a suitably defined replica symmetry breaking solution and we optimise it within a ziggurat ansatz. The generalized order parameter is described by a Parisi-like partial differential equation.Comment: 17 pages, to appear in Annales Henri Poincar\`

Nowcasting COVID-19 incidence indicators during the Italian first outbreak

A novel parametric regression model is proposed to fit incidence data typically collected during epidemics. The proposal is motivated by real-time monitoring and short-term forecasting of the main epidemiological indicators within the first outbreak of COVID-19 in Italy. Accurate short-term predictions, including the potential effect of exogenous or external variables are provided. This ensures to accurately predict important characteristics of the epidemic (e.g., peak time and height), allowing for a better allocation of health resources over time. Parameter estimation is carried out in a maximum likelihood framework. All computational details required to reproduce the approach and replicate the results are provided

Fractional differentiability for solutions of nonlinear elliptic equations

We study nonlinear elliptic equations in divergence form $${\operatorname{div}}{\mathcal A}(x,Du)={\operatorname{div}}G.$$ When ${\mathcal A}$ has linear growth in $Du$, and assuming that $x\mapsto{\mathcal A}(x,\xi)$ enjoys $B^\alpha_{\frac{n}\alpha, q}$ smoothness, local well-posedness is found in $B^\alpha_{p,q}$ for certain values of $p\in[2,\frac{n}{\alpha})$ and $q\in[1,\infty]$. In the particular case ${\mathcal A}(x,\xi)=A(x)\xi$, $G=0$ and $A\in B^\alpha_{\frac{n}\alpha,q}$, $1\leq q\leq\infty$, we obtain $Du\in B^\alpha_{p,q}$ for each $p<\frac{n}\alpha$. Our main tool in the proof is a more general result, that holds also if ${\mathcal A}$ has growth $s-1$ in $Du$, $2\leq s\leq n$, and asserts local well-posedness in $L^q$ for each $q>s$, provided that $x\mapsto{\mathcal A}(x,\xi)$ satisfies a locally uniform $VMO$ condition