Neutralization of IL- 10 produced by B cells promotes protective immunity during persistent HCV infection in humanized mice

Chronic HCV infection can lead to cirrhosis and is associated with increased mortality. Interleukin (IL)- 10- producing B cells (B10 cells) are regulatory cells that suppress cellular immune responses. Here, we aimed to determine whether HCV induces B10 cells and assess the roles of the B10 cells during HCV infection. HCV- induced B10 cells were enriched in CD19hi and CD1dhiCD5+ cell populations. HCV predominantly triggered the TLR2- MyD88- NF- κB and AP- 1 signaling pathways to drive IL- 10 production by B cells. In a humanized murine model of persistent HCV infection, to neutralize IL- 10 produced by B10 cells, mice were treated with pcCD19scFv- IL- 10R, which contains the genes coding the anti- CD19 single- chain variable fragment (CD19scFv) and the extracellular domain of IL- 10 receptor alpha chain (sIL- 10Ra). This treatment resulted in significant reduction of B10 cells in spleen and liver, increase of cytotoxic CD8+ T- cell responses against HCV, and low viral loads in infected humanized mice. Our results indicate that targeting B10 cells via neutralization of IL- 10 may offer a novel strategy to enhance anti- HCV immunotherapy.HCV predominantly triggers the TLR2- MyD88- NF- κB and AP- 1 signaling pathways to drive IL- 10 production by B cells. Neutralization of IL- 10 produced by B10 cells promotes anti- HCV immunity in a humanized murine model of persistent HCV infection. These results provide insight into a novel immunotherapy strategy for HCV treatment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162732/2/eji4736.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162732/1/eji4736_am.pd

Fast kinetics studies of the dynamics of tRNA movement on the ribosome during bacterial translation elongation

During translation elongation tRNAs efficiently move on the surface of the ribosome despite their large sizes. Although structures of tRNA-bound ribosomes are available the dynamics and mechanism of tRNA movement are not clear. The L-shape of tRNA is stabilized by the tertiary core region that contains highly conserved base pairing interactions between the D and T-loops. Distortions of the L-shape accompany tRNA movement across the ribosomal surface suggesting that tRNAs actively interact with the ribosome. Here, using fluorescence labeling and mutagenesis, combined with single turnover rapid kinetics assays, we monitor tRNA movement, and study the importance of the tertiary core region to tRNA functions during bacterial translation elongation. Using tRNAs that are proflavin-labeled, we identify one or possibly two kinetically competent intermediates in the translocation step. A hybrid state intermediate complex can be stabilized by the antibiotic spectinomycin. Studies using a non-hydrolyzable GTP analog, termperature dependence and tRNA mutants indicate that formation of the intermediate is promoted by a conformational change of the ribosome allosterically triggered by EF-G—GTPase, which may require an optimal interaction of the L1 stalk region with the elbow region of the P site tRNA. We also study the effects of disrupting two highly conserved base pairs in the tertiary core region, G18:U55 and G19:C56. The studies suggest that the 18:55 base pair is very important for formation of aminoacyl-tRNA.EF-Tu.GTP ternary complex, initial selection of tRNA on the A/T site of the ribosome, accommodation to A/A site, and translocation of tRNA from P to E site, but not important for translocation of tRNA from A to P site. The 19:56 base pair is important for initial selection only. tRNA activity is almost fully restored in the G19U/C56A double mutant that preserves Watson-Crick base pairing, and the G18A/U55G double mutant, but the G18U/U55A double mutant has low activity. These results suggest that the core region of tRNA not only is important for tRNA stability, but also serves as a locus for functionally important dynamic interactions with the ribosome that promote efficiency and fidelity of translation

MicroRNA Regulation of Human Herpesvirus Latency

Herpesviruses are ubiquitous human pathogens. After productive (lytic) infection, all human herpesviruses are able to establish life-long latent infection and reactivate from it. Latent infection entails suppression of viral replication, maintenance of the viral genome in infected cells, and the ability to reactivate. Most human herpesviruses encode microRNAs (miRNAs) that regulate these processes during latency. Meanwhile, cellular miRNAs are hijacked by herpesviruses to participate in these processes. The viral or cellular miRNAs either directly target viral transcripts or indirectly affect viral infection through host pathways. These findings shed light on the molecular determinants that control the lytic-latent switch and may lead to novel therapeutics targeting latent infection. We discuss the multiple mechanisms by which miRNAs regulate herpesvirus latency, focusing on the patterns in these mechanisms

Synthesis and functional activity of tRNAs labeled with fluorescent hydrazides in the D-loop

We describe an optimized procedure for replacing the dihydrouridine residues of charged tRNAs with Cy3 and Cy5 dyes linked to a hydrazide group, and demonstrate that the labeled molecules are functional in ribosomal activities including 30S initiation complex formation, EF–Tu-dependent binding to the ribosome, translocation, and polypeptide synthesis. This procedure should be straightforwardly generalizable to the incorporation of other hydrazide-linked fluorophores into tRNA or other dihydrouridine-containing RNAs. In addition, we use a rapid turnover FRET experiment, measuring energy transfer between Cy5-labeled tRNAfMet and Cy3-labeled fMetPhe-tRNAPhe, to obtain direct evidence supporting the hypothesis that the early steps of translocation involve movements of the flexible 3′-single-stranded regions of the tRNAs, with the considerable increase in the distance separating the two tRNA tertiary cores occurring later in the process

Atomic‐Scale Observation of the Local Structure and 1D Quantum Effects in vdW Stacking Mo6Te6 Nanowires

Abstract The sub‐nanometer‐diameter transitional‐metal chalcogenides (M6X6) molecular wires are ideal 1D quantum systems. The electronic properties of such system are very sensitive to the interface interaction and local imperfection. Here, the atomic structure and local electronic structure of van der Waals (vdW) stacking Mo6Te6 nanowires fabricated by using molecular beam epitaxy are reported. Atomic‐resolution scanning tunneling microscopy measurement shows that the vdW interface distance varies from 0.71 to 1.05 nm when Mo6Te6 wires stacked on graphite, MoTe2, and Mo6Te6 surfaces. Scanning tunneling spectroscopy confirmed the 1D quantum effect of van Hove singularity and Tomonaga–Luttinger liquid behavior at 77.8 K. Single Te vacancies and their effect to the local structure distortion are observed as well. These observations shed light on the local structure and quantum effects of the M6X6 nanowire materials, which may find applications in future electronic devices

Research Progress on Factors Affecting Oil-Absorption Performance of Cement-Based Materials

With the wide application of petroleum resources, oil substances have polluted the environment in every link from crude oil extraction to utilization. Cement-based materials are the main materials in civil engineering, and the study of their adsorption capacity for oil pollutants can expand the scope of functional engineering applications of cement-based materials. Based on the research status of the oil-wet mechanism of different kinds of oil-absorbing materials, this paper lists the types of conventional oil-absorbing materials and introduces their application in cement-based materials while outlining the influence of different oil-absorbing materials on the oil-absorbing properties of cement-based composites. The analysis found that 10% Acronal S400F emulsion can reduce the water absorption rate of cement stone by 75% and enhance the oil-absorption rate by 62%. Adding 5% polyethylene glycol can increase the oil–water relative permeability of cement stone to 1.2. The oil-adsorption process is described by kinetic and thermodynamic equations. Two isotherm adsorption models and three adsorption kinetic models are explained, and oil-absorbing materials and adsorption models are matched. The effects of specific surface area, porosity, pore interface, material outer surface, oil-absorption strain, and pore network on the oil-absorption performance of materials are reviewed. It was found that the porosity has the greatest influence on the oil-absorbing performance. When the porosity of the oil-absorbing material increases from 72% to 91%, the oil absorption can increase to 236%. In this paper, by analyzing the research progress of factors affecting oil-absorption performance, ideas for multi-angle design of functional cement-based oil-absorbing materials can be obtained

Electron-Beam Irradiation Induced Regulation of Surface Defects in Lead Halide Perovskite Thin Films

Organic-inorganic hybrid perovskites (OIHPs) have been intensively studied due to their fascinating optoelectronic performance. Electron microscopy and related characterization techniques are powerful to figure out their structure-property relationships at the nanoscale. However, electron beam irradiation usually causes damage to these beam-sensitive materials and thus deteriorates the associated devices. Taking a widely used CH3NH3PbI3 film as an example, here, we carry out a comprehensive study on how electron beam irradiation affects its properties. Interestingly, our results reveal that photoluminescence (PL) intensity of the film can be significantly improved along with blue-shift of emission peak at a specific electron beam dose interval. This improvement stems from the reduction of trap density at the CH3NH3PbI3 surface. The knock-on effect helps expose a fresh surface assisted by the surface defect-induced lowering of displacement threshold energy. Meanwhile, the radiolysis process consistently degrades the crystal structure and weaken the PL emission with the increase of electron beam dose. Consequently, the final PL emission comes from a balance between knock-on and radiolysis effects. Taking advantage of the defect regulation, we successfully demonstrate a patterned CH3NH3PbI3 film with controllable PL emission and a photodetector with enhanced photocurrent. This work will trigger the application of electron beam irradiation as a powerful tool for perovskite materials processing in micro-LEDs and other optoelectronic applications

A Herpesviral Lytic Protein Regulates the Structure of Latent Viral Chromatin

ABSTRACT Latent infections by viruses usually involve minimizing viral protein expression so that the host immune system cannot recognize the infected cell through the viral peptides presented on its cell surface. Herpes simplex virus (HSV), for example, is thought to express noncoding RNAs such as latency-associated transcripts (LATs) and microRNAs (miRNAs) as the only abundant viral gene products during latent infection. Here we describe analysis of HSV-1 mutant viruses, providing strong genetic evidence that HSV-infected cell protein 0 (ICP0) is expressed during establishment and/or maintenance of latent infection in murine sensory neurons in vivo. Studies of an ICP0 nonsense mutant virus showed that ICP0 promotes heterochromatin and latent and lytic transcription, arguing that ICP0 is expressed and functional. We propose that ICP0 promotes transcription of LATs during establishment or maintenance of HSV latent infection, much as it promotes lytic gene transcription. This report introduces the new concept that a lytic viral protein can be expressed during latent infection and can serve dual roles to regulate viral chromatin to optimize latent infection in addition to its role in epigenetic regulation during lytic infection. An additional implication of the results is that ICP0 might serve as a target for an antiviral therapeutic acting on lytic and latent infections