Role of endoplasmic reticulum aminopeptidases in health and disease: from infection to cancer

Endoplasmic reticulum (ER) aminopeptidases ERAP1 and ERAP2 (ERAPs) are essential for the maturation of a wide spectrum of proteins involved in various biological processes. In the ER, these enzymes work in concert to trim peptides for presentation on MHC class I molecules. Loss of ERAPs function substantially alters the repertoire of peptides presented by MHC class I molecules, critically affecting recognition of both NK and CD8(+) T cells. In addition, these enzymes are involved in the modulation of inflammatory responses by promoting the shedding of several cytokine receptors, and in the regulation of both blood pressure and angiogenesis. Recent genome-wide association studies have identified common variants of ERAP1 and ERAP2 linked to several human diseases, ranging from viral infections to autoimmunity and cancer. More recently, inhibition of ER peptide trimming has been shown to play a key role in stimulating innate and adaptive anti-tumor immune responses, suggesting that inhibition of ERAPs might be exploited for the establishment of innovative therapeutic approaches against cancer. This review summarizes data currently available for ERAP enzymes in ER peptide trimming and in other immunological and non-immunological functions, paying attention to the emerging role played by these enzymes in human diseases.     

The ITER full size plasma source device design

In the framework of the strategy for the development and the procurement of the NB systems for ITER, it has been decided to build in Padova a test facility, including two experimental devices: a full size plasma source with low voltage extraction and a full size NB injector at full beam power (1 MV). These two different devices will separately address the main scientific and technological issues of the 17 MW NB injector for ITER. In particular the full size plasma source of negative ions will address the ITER performance requirements in terms of current density and uniformity, limitation of the electron/ion ratio and stationary operation at full current with high reliability and constant performances for the whole operating time up to 1 h. The required negative ion current density to be extracted from the plasma source ranges from 290 A/m² in D₂ (D^?) and 350 A/m² in H₂ (H^?) and these values should be obtained at the lowest admissible neutral pressure in the plasma source volume, nominally at 0.3 Pa. The electron to ion ratio should be limited to less than 1 and the admissible ion inhomogeneity extracted from the grids should be better than 10% on the whole plasma cross-section having a surface exposed to the extraction grid of the order of 1 m².The main design choices will be presented in the paper as well as an overview of the design of the main components and systems.     

Power Factor Enhancement by Inhomogeneous Distribution of Dopants in Two-Phase Nanocrystalline Systems

In this work, we describe a novel idea that allows for high thermoelectric power factors in two-phase materials that are heavily doped with an inhomogeneous distribution of dopants. We show that a concurrent increase of the electrical conductivity and Seebeck coefficient and a consequent increase of the power factor can be achieved in such systems. To explain the concept, we employ a semiclassical one-dimensional model that considers both electron and phonon transport through a series connection of two-phases of the material. We discuss microscopic characteristics of the material and the formation of the two phases (grains and grain boundaries in our case) by the inhomogeneous distribution of dopants in the polycrystalline material. Our theoretical investigation reveals that: (1) the improvement in the Seebeck coefficient can be attributed to carrier filtering due to the energy barriers at the grain boundaries, and to the difference in the lattice thermal conductivity of the grains and grain boundaries, and (2) the improvement in the electrical conductivity is a result of a high Fermi level in the grains. This allows high energy carriers to contribute to transport, which increases the impurity scattering limited mean-free-path, and increases the conductivity in the grains and thus in the whole material. Such an unexpected concurrent increase of the electrical conductivity and the Seebeck coefficient was recently observed in heavily boron-doped polycrystalline silicon of grain sizes <100 nm in which a silicon-boride phase is formed around the grain boundaries. We provide a simple 1D model that explains the behavior of this system, indicating processes that can take place in heavily doped nanocrystalline materials.     

A minimal receptor-Ig chimera of human Fc{varepsilon}RI {alpha}-chain efficiently binds secretory and membrane IgE

We constructed a soluble minimal receptor-Ig chimera in whichthe two extracellular domains of human Fc     

Leaching and Solubility Analysis of Porcelain-Recycled Tile Residues in Clay Bricks

In this study, a porcelain tile residue was used to produce clay bricks. The residue was characterized (XRF, PSD, dilatometry, solubility, and leaching analyses) and was added to a brick paste, forming compositions that were extruded, dried, and fired at 1000°C. The fired specimens were tested [compressive strength, shrinkage, apparent density, water absorption, phase analysis (XRD), microstructure (SEM), leaching, and solubility]. The results showed that the porcelain residue was a noninert material. When added to the brick paste, the residue shows an improvement of some properties due to its alkaline content acting as a flux in the clay paste and causing the vitrification of the structure.     

Simple Preparation of Dimeric Cinchona Alkaloid Derivatives on Polystyrene Supports and a Highly Enantioselective Catalytic Heterogeneous Dimerization of Ketenes

A convenient route for the covalent immobilization of quinidine and hydroquinidine pyridazine ethers on insoluble polystyrene supports is described, which avoids the need of chromatographic purifications at any stage. The use of the heterogeneized alkaloid derivatives in the asymmetric organocatalytic dimerization of ketenes afforded high enantioselectivity values (90–97% ee) in the course of 20 reaction cycles.     

Cultivation of hamster kidney cells in a dynamic cell culture system in space (Spacelab IML-1 Mission)

Cell proliferation, tissue plasminogen activator (t-PA) production and metabolic changes of Hamster Kidney cells (HaK) grown on microcarriers in an automatic Dynamic Cell Culture System (DCCS) were determined on the first International Microgravity Mission (IML-1) Spacelab (22-30 January 1992). The DCCS was designed for two cell culture chambers (volume: 200 microliters each), one operating as a hatch system, the other as a perfusion system. Medium exchange was achieved with an osmotic pump (flow rate 1 microliter h-1). Two major items were investigated: the biological performance of the DCCS in space and the effect of microgravity on HaK cells. The results obtained demonstrated that (1) the DCCS can be used for biological experiments on long term Spacelab missions. In fact, higher cell densities and higher concentration of glucose but lower concentration of lactate in the perfusion chambers than in the batch chambers were measured. The concentration of t-PA, glutamine and ammonia was similar in all chambers. (2) Microgravity had no effect on cell growth and metabolism of HaK cells.     

Affinity capillary electrophoresis using a low-concentration additive with the consideration of relative mobilities

Most affinity studies in capillary electrophoresis assume that the analyte concentration is much smaller than the additive concentration so that the migration of the analyte has no effect on the concentration of the additive in the capillary. However, in most medium- to high-affinity interactions, the additive concentration has to be kept rather low to observe the changes in analyte mobility before saturation is reached. In this paper, a mathematical model is developed to describe the migration behavior of the analyte in a system where the complex formed becomes concentrated to levels much greater than the original concentration of the additive due to the differences in the mobilities of the analyte, additive, and complex. The analyte is flurbiprofen, the additive is transthyretin, and the stoichiometry of the reaction between the two is 1:2. This study also provides a new algorithm to determine medium- to high-affinity binding interaction constants by CE.     

Measuring Molecular Diffusion in Dynamic Subcellular Nanostructures by Fast Raster Image Correlation Spectroscopy and 3D Orbital Tracking

Here we provide demonstration that fast fluorescence fluctuation spectroscopy is a fast and robust approach to extract information on the dynamics of molecules enclosed within subcellular nanostructures (e.g., organelles or vesicles) which are also moving in the complex cellular environment. In more detail, Raster Image Correlation Spectroscopy (RICS) performed at fast timescales (i.e., microseconds) reveals the fast motion of fluorescently labeled molecules within two exemplary dynamic subcellular nanostructures of biomedical interest, the lysosome and the insulin secretory granule (ISG). The measurement of molecular diffusion is then used to extract information on the average properties of subcellular nanostructures, such as macromolecular crowding or molecular aggregation. Concerning the lysosome, fast RICS on a fluorescent tracer allowed us to quantitatively assess the increase in organelle viscosity in the pathological condition of Krabbe disease. In the case of ISGs, fast RICS on two ISG-specific secreting peptides unveiled their differential aggregation propensity depending on intragranular concentration. Finally, a combination of fast RICS and feedback-based 3D orbital tracking was used to subtract the slow movement of subcellular nanostructures from the fast diffusion of molecules contained within them and independently validate the results. Results presented here not only demonstrate the acquired ability to address the dynamic behavior of molecules in moving, nanoscopic reference systems, but prove the relevance of this approach to advance our knowledge on cell function at the subcellular scale.