Endothelial Protein Disulphide Isomerase-A1 enhances membrane stiffness and platelet-endothelium interaction in hyperglycaemia via SLC3A2 and LAMC1.

BACKGROUND: Diabetes carries an increased risk of cardiovascular disease and thromboembolic events. Upon endothelial dysfunction, platelets bind to endothelial cells to precipitate thrombus formation, however, it is unclear which surface proteins regulate platelet-endothelium interaction. We and others have shown that peri/epicellular (pec) protein disulphide isomerase A1 (pecPDI) influences the adhesion and migration of vascular cells. OBJECTIVES: We investigated whether pecPDI regulates adhesion-related molecules on the surface of endothelial cells and platelets that influence the binding of these cells in hyperglycaemia. METHODS: Immunofluorescence was used to assess platelet-endothelium interaction in vitro, cytoskeleton reorganization and focal adhesions. Hydrogen peroxide production was assessed via Amplex Red assays. Cell biophysics was assessed using atomic force microscopy. Secreted proteins of interest were identified through proteomics (secretomics) and targets were knocked down using siRNA. PDI contribution was assessed using whole-cell PDI or pecPDI inhibitors or siRNA. RESULTS: Platelets of healthy donors adhered more onto hyperglycaemic HUVECs. Endothelial, but not platelet, pecPDI regulated this effect. Hyperglycaemic HUVECs showed marked cytoskeleton reorganization, increased H2O2 production and elongated focal adhesions. Indeed, hyperglycaemic HUVECs were stiffer compared to normoglycaemic cells. PDI and pecPDI inhibition reversed the abovementioned processes in hyperglycaemic cells. A secretomics analysis revealed eight proteins secreted in a PDI-dependent manner by hyperglycaemic cells. Among these, we showed that genetic deletion of LAMC1 and SLC3A2 decreased platelet-endothelium interaction and did not potentiate the effects of PDI inhibitors. CONCLUSIONS: Endothelial pecPDI regulates platelet-endothelium interaction in hyperglycemia through adhesion-related proteins and alterations in endothelial membrane biophysics.

Nanomechanical and Vibrational Signature of Chikungunya Viral Particles.

Chikungunya virus (CHIKV) belongs to the genus Alphaviridae, with a single-stranded positive-sense RNA genome of 11.8 kbp encoding a polyprotein that generates both non-structural proteins and structural proteins. The virus is transmitted by the Aedes aegypti and A. albopictus mosquitoes, depending on the location. CHIKV infection leads to dengue-like musculoskeletal symptoms and has been responsible for several outbreaks worldwide since its discovery in 1952. Patients often experience fever, headache, muscle pain, joint swelling, and skin rashes. However, the ultrastructural and mechanical properties of CHIKV have not been fully characterized. Thus, this study aims to apply a physical approach to investigate CHIKV's ultrastructural morphology and mechanical properties, using atomic force microscopy and Raman spectroscopy as the main tools. Using nanomechanical assays of AFM and a gold nanoparticles substrate for Raman signal enhancement, we explored the conformational plasticity, morphology, vibrational signature, and nanomechanical properties of the chikungunya virus, providing new information on its ultrastructure at the nanoscale and offering a novel understanding of the virus' behavior upon mechanical disruptions besides its molecular composition.

Silver Trimolybdate (Ag2Mo3O10.2H2O) Nanorods: Synthesis, Characterization, and Photo-Induced Antibacterial Activity under Visible-Light Irradiation.

The present study reports the synthesis, characterization, and antibacterial properties of silver trimolybdate (Ag2Mo3O10.2H2O) nanorods. The synthesis was performed using a conventional hydrothermal method. The sample was characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis-NIR diffuse reflectance, thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). The direct antibacterial activity was evaluated using the microdilution method to determine the minimum inhibitory concentration (MIC). To assess the ability of Ag2Mo3O10.2H2O nanorods to modulate antibacterial resistance, the MIC of aminoglycosides was established in the presence of a subinhibitory concentration of this substance alone and associated with LED light exposure. The characterization of the sample indicated that the synthesis of silver trimolybdate generated nanometric crystals with rod-like morphology, without secondary phases. The treatment with Ag2Mo3O10.2H2O nanorods alone or combined with visible LED lights exhibited clinically relevant antibacterial activity against both Gram-negative and Gram-positive bacteria. This nanostructure presented a variable antibiotic-modulating action, which was not improved by visible LED light exposure. Nevertheless, LED lights showed promising antibiotic-enhancing activities in the absence of Ag2Mo3O10.2H2O nanorods. In conclusion, silver trimolybdate dihydrate nanorods have antibacterial properties that can be photocatalysed by visible-light exposure. While showing the potential use to combat antibacterial resistance, the simultaneous combination of silver trimolybdate, visible LED lights, and antibacterial drugs should be carefully analysed to avoid antagonist effects that could impair the effectiveness of antibiotic therapy.

Raman Spectroscopy Studies on the Barocaloric Hybrid Perovskite [(CH3)4N][Cd(N3)3].

Temperature-dependent Raman scattering and differential scanning calorimetry were applied to the study of the hybrid organic-inorganic azide-perovskite [(CH3)4N][Cd(N3)3], a compound with multiple structural phase transitions as a function of temperature. A significant entropy variation was observed associated to such phase transitions, |∆S| ~ 62.09 J·kg-1 K-1, together with both a positive high barocaloric (BC) coefficient |δTt/δP| ~ 12.39 K kbar-1 and an inverse barocaloric (BC) coefficient |δTt/δP| ~ -6.52 kbar-1, features that render this compound interesting for barocaloric applications. As for the obtained Raman spectra, they revealed that molecular vibrations associated to the NC4, N3- and CH3 molecular groups exhibit clear anomalies during the phase transitions, which include splits and discontinuity in the phonon wavenumber and lifetime. Furthermore, variation of the TMA+ and N3- modes with temperature revealed that while some modes follow the conventional red shift upon heating, others exhibit an unconventional blue shift, a result which was related to the weakening of the intermolecular interactions between the TMA (tetramethylammonium) cations and the azide ligands and the concomitant strengthening of the intramolecular bondings. Therefore, these studies show that Raman spectroscopy is a powerful tool to gain information about phase transitions, structures and intermolecular interactions between the A-cation and the framework, even in complex hybrid organic-inorganic perovskites with highly disordered phases.