Optical absorption in fused silica during TRIGA reactor pulse irradiation

Spectral transmission characteristics of fused silica before, during, and after exposure to reactor irradiation pulse

The power of photons: Cavity-mediated energy transfer between quantum devices

The coherent energy transfer between a quantum charger and a quantum battery is analyzed. In particular, we study how to improve the direct energy transfer by adding a photonic cavity as a mediator. We show that the additional degree of freedom given by the photons consistently improves the transfer performances, above all in the off-resonant case, where there is a mismatch in the energy levels. An experimental feasible way to switch-on and off the interaction between each part of the systems and the possibility of changing the energy levels mismatch will be described, in view of finding the best working setup

Transcriptional response of the heart to vagus nerve stimulation.

Heart failure is a major clinical problem, with treatments involving medication, devices, and emerging neuromodulation therapies such as vagus nerve stimulation (VNS). Considering the ongoing interest in using VNS to treat cardiovascular disease it is important to understand the genetic and molecular changes developing in the heart in response to this form of autonomic neuromodulation. This experimental animal (rat) study investigated the immediate transcriptional response of the ventricular myocardium to selective stimulation of vagal efferent activity using an optogenetic approach. Vagal preganglionic neurons in the dorsal motor nucleus of the vagus nerve were genetically targeted to express light-sensitive chimeric channelrhodopsin variant ChIEF, and stimulated using light. RNA sequencing of left ventricular myocardium identified 294 differentially expressed genes (DEGs, false discovery rate <0.05). Qiagen Ingenuity Pathway Analysis (IPA) highlighted 118 canonical pathways that were significantly modulated by vagal activity, of which 14 had a z-score of ≥2/≤-2, including EIF-2, IL-2, Integrin, and NFAT-regulated cardiac hypertrophy. IPA revealed the effect of efferent vagus stimulation on protein synthesis, autophagy, fibrosis, autonomic signalling, inflammation, and hypertrophy. IPA further predicted that the identified DEGs were the targets of 50 upstream regulators, including transcription factors (e.g., MYC, NRF1) and microRNAs (e.g., miR-335-3p, miR-338-3p). These data demonstrate that the vagus nerve has a major impact on myocardial expression of genes involved in regulation of key biological pathways. The transcriptional response of the ventricular myocardium induced by stimulation of vagal efferents is consistent with the beneficial effect of maintained/increased vagal activity on the heart

3D GRID-based pharmacophore and Metadynamics approaches for the rational design of N-Methyl β-sheet breaker peptides as inhibitors of the Alzheimer's Aβ-amyloid fibrillogenesis

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the loss of the cognitive functions and dementia. Several scientific evidences report that a central role in the pathogenesis of AD is played by the brain deposition of insoluble aggregates of β-amyloid protein (Aβ) proteins, thus causing neuronal cell death [1]. For this reason, one of the promising approach is to inhibit the aggregation of Aβ peptides. Because Aβ is self-assembling, one possible strategy to prevent this process is to use short peptide fragments homologous to the full-length wild-type Aβ protein. From this consideration, several short synthetic peptides were designed as beta-sheet breakers (BSB) [2]. In particular, the pentapetide Ac-LPFFD-NH2 (iAβ5p) exhibited a certain capability to inhibit Aβ fibrillogenesis [3]. iAβ5p analogs [4] were, then, designed by introducing N-Methylation at the amide bond nitrogen were also promising BSB. Here, we describe the methodological approach, which combines 3D GRID-based pharmacophore peptide screening with Well-Tempered Metadynamics simulations aimed to the discovery of novel N-Methylated BSB. This approach led us to identify two promising, cell permeable, N-Methylated peptides that were further evaluated for their BSB properties showing a significant improvement of the fibrillogenesis inhibition with respect to the lead iAβ5p

Production and purification of chimeric HBc virus-like particles carrying influenza virus LAH domain as vaccine candidates

Background: The lack of a universal influenza vaccine is a global health problem. Interest is now focused on structurally conserved protein domains capable of eliciting protection against a broad range of influenza virus strains. The long alpha helix (LAH) is an attractive vaccine component since it is one of the most conserved influenza hemagglutinin (HA) stalk regions. For an improved immune response, the LAH domain from H3N2 strain has been incorporated into virus-like particles (VLPs) derived from hepatitis B virus core protein (HBc) using recently developed tandem core technology. Results: Fermentation conditions for recombinant HBc-LAH were established in yeast Pichia pastoris and a rapid and efficient purification method for chimeric VLPs was developed to match the requirements for industrial scale-up. Purified VLPs induced strong antibody responses against both group 1 and group 2 HA proteins in mice. Conclusion: Our results indicate that the tandem core technology is a useful tool for incorporation of highly hydrophobic LAH domain into HBc VLPs. Chimeric VLPs can be successfully produced in bioreactor using yeast expression system. Immunologic data indicate that HBc VLPs carrying the LAH antigen represent a promising universal influenza vaccine component

Intracellular trafficking, localization, and mobilization of platelet-borne thiol isomerases

OBJECTIVE: Thiol isomerases facilitate protein folding in the endoplasmic reticulum, and several of these enzymes, including protein disulfide isomerase and ERp57, are mobilized to the surface of activated platelets, where they influence platelet aggregation, blood coagulation, and thrombus formation. In this study, we examined the synthesis and trafficking of thiol isomerases in megakaryocytes, determined their subcellular localization in platelets, and identified the cellular events responsible for their movement to the platelet surface on activation. APPROACH AND RESULTS: Immunofluorescence microscopy imaging was used to localize protein disulfide isomerase and ERp57 in murine and human megakaryocytes at various developmental stages. Immunofluorescence microscopy and subcellular fractionation analysis were used to localize these proteins in platelets to a compartment distinct from known secretory vesicles that overlaps with an inner cell-surface membrane region defined by the endoplasmic/sarcoplasmic reticulum proteins calnexin and sarco/endoplasmic reticulum calcium ATPase 3. Immunofluorescence microscopy and flow cytometry were used to monitor thiol isomerase mobilization in activated platelets in the presence and absence of actin polymerization (inhibited by latrunculin) and in the presence or absence of membrane fusion mediated by Munc13-4 (absent in platelets from Unc13dJinx mice). CONCLUSIONS: Platelet-borne thiol isomerases are trafficked independently of secretory granule contents in megakaryocytes and become concentrated in a subcellular compartment near the inner surface of the platelet outer membrane corresponding to the sarco/endoplasmic reticulum of these cells. Thiol isomerases are mobilized to the surface of activated platelets via a process that requires actin polymerization but not soluble N-ethylmaleimide-sensitive fusion protein attachment receptor/Munc13-4-dependent vesicular-plasma membrane fusion

A virus-like particle vaccine candidate for influenza A virus based on multiple conserved antigens presented on hepatitis B tandem core particles

Existing Influenza A virus (IAV) vaccines target variable parts of the virus that may change between seasons. Vaccine design relies on predicting the predominant circulating influenza strains but when there is a mismatch between vaccine and circulating strains, efficacy is sub-optimal. Furthermore, current approaches provide limited protection against emerging influenza strains that may cause pandemics. One solution is to design vaccines that target conserved protein domains of influenza, which remain largely unchanged over time and are likely to be found in emergent variants. We present a virus-like particle (VLP), built using the hepatitis B virus tandem core platform, as an IAV vaccine candidate containing multiple conserved antigens. Hepatitis B core protein spontaneously assembles into a VLP that is immunogenic and confers immunogenicity to proteins incorporated into the major insertion region (MIR) of core monomers. However, insertion of antigen sequences may disrupt particle assembly preventing VLP formation or result in unstable particles. We have overcome these problems by genetically manipulating the hepatitis B core to express core monomers in tandem, ligated with a flexible linker, incorporating different antigens at each of the MIRs. Immunisation with this VLP, named Tandiflu1, containing 4 conserved antigens from matrix protein 2 ectodomain and hemagglutinin stalk, leads to production of cross-reactive and protective antibodies. The polyclonal antibodies induced by Tandiflu1 can bind IAV Group 1 hemagglutinin types H1, H5, H11, H9, H16 and a conserved epitope on matrix protein 2 expressed by most strains of IAV. Vaccination with Tandiflu1 results in 100% protection from a lethal influenza challenge with H1N1 IAV. Serum transfer from vaccinated animals is sufficient to confer protection from influenza-associated illness in naïve mice. These data suggest that a Tandem Core based IAV vaccine might provide broad protection against common and emergent H1 IAV strains responsible for seasonal and pandemic influenza in man

Cell-Specific Gene Deletion Reveals the Antithrombotic Function of COX1 and Explains the Vascular COX1/Prostacyclin Paradox.

Rationale: Endothelial cells (ECs) and platelets, which respectively produce antithrombotic prostacyclin and prothrombotic thromboxane A2, both express COX1 (cyclooxygenase1). Consequently, there has been no way to delineate any antithrombotic role for COX1-derived prostacyclin from the prothrombotic effects of platelet COX1. By contrast, an antithrombotic role for COX2, which is absent in platelets, is straightforward to demonstrate. This has resulted in an incomplete understanding of the relative importance of COX1 versus COX2 in prostacyclin production and antithrombotic protection in vivo. Objective: We sought to identify the role, if any, of COX1-derived prostacyclin in antithrombotic protection in vivo and compare this to the established protective role of COX2. Methods and Results: We developed vascular-specific COX1 knockout mice and studied them alongside endothelial-specific COX2 knockout mice. COX1 immunoreactivity and prostacyclin production were primarily associated with the endothelial layer of aortae; freshly isolated aortic ECs released >10-fold more prostacyclin than smooth muscle cells. Moreover, aortic prostacyclin production, the ability of aortic rings to inhibit platelet aggregation and plasma prostacyclin levels were reduced when COX1 was knocked out in ECs but not in smooth muscle cells. When thrombosis was measured in vivo after FeCl3 carotid artery injury, endothelial COX1 deletion accelerated thrombosis to a similar extent as prostacyclin receptor blockade. However, this effect was lost when COX1 was deleted from both ECs and platelets. Deletion of COX2 from ECs also resulted in a prothrombotic phenotype that was independent of local vascular prostacyclin production. Conclusions: These data demonstrate for the first time that, in healthy animals, endothelial COX1 provides an essential antithrombotic tone, which is masked when COX1 activity is lost in both ECs and platelets. These results help us define a new 2-component paradigm wherein thrombotic tone is regulated by both COX1 and COX2 through complementary but mechanistically distinct pathways

Profiling the eicosanoid networks that underlie the anti- and pro-thrombotic effects of aspirin

Aspirin prevents thrombosis by inhibiting platelet cyclooxygenase (COX)-1 activity and the production of thromboxane (Tx)A2, a pro-thrombotic eicosanoid. However, the non-platelet actions of aspirin limit its antithrombotic effects. Here we used platelet-COX-1-ko mice to define the platelet and non-platelet eicosanoids affected by aspirin. Mass-spectrometry analysis demonstrated blood from platelet-COX-1-ko and global-COX- 1-ko mice produced similar eicosanoid profiles in vitro: e.g. formation of TxA2, prostaglandin (PG) F2, 11-HETE and 15-HETE was absent in both platelet- and global-COX-1-ko mice. Conversely, in vivo, platelet-COX-1-ko mice had a distinctly different profile from global-COX-1-ko or aspirin-treated control mice, notably significantly higher levels of PGI2 metabolite. Ingenuity Pathway Analysis predicted that platelet-COX-1-ko mice would be protected from thrombosis, forming less prothrombotic TxA2 and PGE2. Conversely, aspirin or lack of systemic COX-1 activity decreased the synthesis of anti-aggregatory PGI2 and PGD2 at non-platelet sites leading to predicted thrombosis increase. In vitro and in vivo thrombosis studies proved these predictions. Overall, we have established the eicosanoid profiles linked to inhibition of COX-1 in platelets and in the remainder of the cardiovascular system and linked them to anti- and pro-thrombotic effects of aspirin. These results explain why increasing aspirin dosage or aspirin addition to other drugs may lessen anti-thrombotic protection