Glutamatergic Reinnervation and Assembly of Glutamatergic Synapses in Adult Rat Skeletal Muscle Occurs at Cholinergic Endplates

After denervation of adult rat abdominal muscles, the postsynaptic apparatus of neuromuscular junctions (NMJs) retains its original architecture and clustering of acetylcholine receptors (AChRs). When descending fibers of the spinal cord are surgically diverted to this muscle by a nerve grafting procedure, supraspinal glutamatergic neurons can innervate muscle fibers and restore motor function; the newly formed NMJs switch from a cholinergic to a glutamatergic-type synapse. We show here that regenerating nerve endings contact the fibers in an area occupied by cholinergic endplates. These NMJs are morphologically indistinguishable from those in controls, but they differ in the subunit composition of AChRs. Moreover, by immunofluorescence and immunoelectron microscopy, new NMJs express glutamatergic synapse markers. The \u3b1-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR1 partially colocalizes with AChRs, and vesicular glutamate transporter 2 is localized in the presynaptic compartment. Immunoprecipitation analysis of membranes from reinnervated muscle showed that AMPA receptor subunits GluR1 and GluR2 coimmunoprecipitate with rapsyn, the AChR-anchoring protein at the NMJ. Taken together, these results indicate that cholinergic endplates can be targeted by new glutamatergic projections and that the clustering of AMPA receptors occurs there

Trends in chronic hepatitis B virus infection in Italy over a 10-year period: Clues from the nationwide PITER and MASTER cohorts toward elimination

Objectives: The study measures trends in the profile of patients with chronic hepatitis B virus linked to care in Italy. Methods: A cross-sectional, multicenter, observational cohort (PITER cohort) of consecutive patients with hepatitis B surface antigen (HBsAg) over the period 2019-2021 from 46 centers was evaluated. The reference was the MASTER cohort collected over the years 2012-2015. Standard statistical methods were used. Results: The PITER cohort enrolled 4583 patients, of whom 21.8% were non-Italian natives. Compared with those in MASTER, the patients were older and more often female. The prevalence of hepatitis B e antigen (HBeAg) declined (7.2% vs 12.3; P <0.0001) and that of anti-hepatitis D virus (HDV) remained stable (9.3% vs 8.3%). In both cohorts, about 25% of the patients had cirrhosis, and those in the PITER cohort were older. HBeAg-positive was 5.0% vs 12.6% (P <0.0001) and anti-HDV positive 24.8% vs 17.5% (P <0.0017). In the logistic model, the variables associated with cirrhosis were anti-HDV-positive (odds ratio = 10.08; confidence interval 7.63-13.43), age, sex, and body mass index; the likelihood of cirrhosis was reduced by 40% in the PITER cohort. Among non-Italians, 12.3% were HBeAg-positive (vs 23.4% in the MASTER cohort; P <0.0001), and 12.3% were anti-HDV-positive (vs 11.1%). Overall, the adherence to the European Association for the Study of the Liver recommendations for antiviral treatment increased over time. Conclusion: Chronic hepatitis B virus infection appears to be in the process of becoming under control in Italy; however, HDV infection is still a health concern in patients with cirrhosis and in migrants

Dust Environment Model of the Interstellar Comet 2I/Borisov

2I/Borisov is the first interstellar comet discovered on 2019 August 30, and it soon showed a coma and a dust tail. This study reports the results of images obtained at the Telescopio Nazionale Galileo telescope, on La Palma - Canary Islands, in 2019 November and December. The images have been obtained with the R filter in order to apply our dust tail model. The model has been applied to the comet 67P/Churyumov-Gerasimenko and compared to the Rosetta dust measurements showing a very good agreement. It has been applied to the comet 2I/Borisov, using almost the same parameters, obtaining a dust environment similar to that of 67P/Churyumov-Gerasimenko, suggesting that the activity may be very similar. The dust tail analysis provided a dust-loss rate Qd ≍ 35 kg s-1 in 2019 November and Qd ≍ 30 kg s-1 in 2019 December

CUBES: a UV spectrograph for the future

In spite of the advent of extremely large telescopes in the UV/optical/NIR range, the current generation of 8-10m facilities is likely to remain competitive at ground-UV wavelengths for the foreseeable future. The Cassegrain U-Band Efficient Spectrograph (CUBES) has been designed to provide high-efficiency (>40%) observations in the near UV (305-400 nm requirement, 300-420 nm goal) at a spectral resolving power of R>20,000, although a lower-resolution, sky-limited mode of R ~ 7,000 is also planned. CUBES will offer new possibilities in many fields of astrophysics, providing access to key lines of stellar spectra: a tremendous diversity of iron-peak and heavy elements, lighter elements (in particular Beryllium) and light-element molecules (CO, CN, OH), as well as Balmer lines and the Balmer jump (particularly important for young stellar objects). The UV range is also critical in extragalactic studies: the circumgalactic medium of distant galaxies, the contribution of different types of sources to the cosmic UV background, the measurement of H2 and primordial Deuterium in a regime of relatively transparent intergalactic medium, and follow-up of explosive transients. The CUBES project completed a Phase A conceptual design in June 2021 and has now entered the Phase B dedicated to detailed design and construction. First science operations are planned for 2028. In this paper, we briefly describe the CUBES project development and goals, the main science cases, the instrument design and the project organization and management

Liposomes functionalized to overcome the blood–brain barrier and to target amyloid-β peptide: the chemical design affects the permeability across an in vitro model

Elisa Salvati, Francesca Re, Silvia Sesana, Ilaria Cambianica, Giulio Sancini, Massimo Masserini, Maria GregoriDepartment of Health Sciences, University of Milano-Bicocca, Monza, ItalyPurpose: We investigated the ability of amyloid-β-targeting liposomes, decorated with an anti-transferrin receptor antibody, to cross the blood–brain barrier (BBB), comparing two antibody ligation techniques.Methods: Fluorescent or radiolabeled liposomes composed of sphingomyelin/cholesterol and containing phosphatidic acid, known to bind amyloid-β, were further functionalized with the anti-transferrin receptor antibody RI7217. Two different techniques were used to attach RI7217 to the liposomes surface: biotin/streptavidin linkage or thiol–maleimide covalent ligation. Surface plasmon resonance (SPR) and immunoblotting were employed to assess the nanoparticles’ binding performances. Confocal microscopy and radiochemical techniques were used for uptake and permeability studies on an in vitro BBB model made of human brain capillary endothelial cells hCMEC/D3.Results: Immunoblotting experiments showed that RI7217-functionalized liposomes bind to transferrin receptor independently of the procedure employed to ligate their surface with the antibody, while SPR experiments showed a slightly higher affinity for covalently functionalized nanoliposomes. The functionalization with RI7217 did not affect the liposomes’ affinity for amyloid-β. The functionalization of liposomes with RI7217, independently of the ligation procedure, gave higher values of uptake and permeability across the barrier model in comparison to the nondecorated ones, without cell monolayer alterations. Of note, the best performing particles were those covalently coupled with the antibody. The ratios of the two radiolabeled lipids (3H-sphingomyelin and 14C-phosphatidic acid) present in the liposome bilayer were found to be similar in the apical and in the basolateral compartments of the barrier model, suggesting that liposomes were transported intact across the cell monolayer. Confocal experiments showed no co-localization of RI7217-liposomes with early/late endosomes or early lysosomes.Conclusion: Our results suggest that RI7217 promotes the in vitro barrier crossing of liposomes containing phosphatidic acid, targeting the Alzheimer’s disease amyloid-β peptide. Moreover, for the first time, we prove herein the superior efficiency of covalent coupling of RI7217 versus biotin/streptavidin ligation to facilitate liposomes in overcoming the BBB in vitro.Keywords: liposomes, blood–brain barrier, amyloid-β peptide, RI7217, antibody conjugation, surface plasmon resonanc