Hepatitis C Virus Sensitizes Host Cells to TRAIL-Induced Apoptosis by Up-Regulating DR4 and DR5 via a MEK1-Dependent Pathway

BACKGROUND: Hepatitis C virus (HCV) is the leading cause of liver fibrosis, cirrhosis and hepatocellular carcinoma. It is believed that continuous liver cell apoptosis contributes to HCV pathogenesis. Recent studies have shown that HCV infection can sensitize host cells to TNF-related apoptosis-inducing ligand (TRAIL) induced apoptosis, but the mechanism by which HCV regulates the TRAIL pathway remains unclear. METHODS AND RESULTS: Using a sub-genomic replicon and full length virus, JFH-1, we demonstrate that HCV can sensitize host cells to TRAIL-induced apoptosis by up-regulating two TRAIL receptors, death receptor 4 (DR4) and death receptor 5 (DR5). Furthermore, the HCV replicon enhanced transcription of DR5 via Sp1, and the HCV-mediated up-regulation of DR4 and DR5 required MEK1 activity. HCV infection also stimulated the activity of MEK1, and the inhibition of MEK1 activity or the knockdown of MEK1 increased the replication of HCV. CONCLUSIONS: Our studies demonstrate that HCV replication sensitizes host cells to TRAIL-induced apoptosis by up-regulating DR4 and DR5 via a MEK1 dependent pathway. These findings may help to further understand the pathogenesis of HCV infection and provide a therapeutic target

Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

Defects guided wrinkling in graphene on copper substrate

Pristine graphene depositing on metallic substrates often wrinkles when the film-substrate system undergoes a temperature drop from the chemical vapor deposition (CVD) chamber to ambient environment. The pattern of wrinkles is governed by the crystallographic planes of the substrates and the defects in the film. In this paper, we report how commonly seen Stone-Wales defects and grain boundaries (GBs) influence the morphology of graphene on different planes of single crystalline copper substrate. Stone-Wales defects weaken the bending stiffness in graphene, and result in wrinkling along the defect direction. In the presence of GBs, primary wrinkles are always parallel to the GB direction, and there are also secondary wrinkles perpendicular to the GB. In combination with planes of the substrate and the orientation of defects, we demonstrate that we may manipulate wrinkling patterns for possible engineering applications. (C) 2018 Elsevier Ltd. All rights reserved

Local electrochemical reactivity of single layer graphene deposited on flexible and transparent plastic film using scanning electrochemical microscopy

International audienc

Interaction of human arylamine n-acetyltransferase 1 with different nanomaterials

Humans are exposed to nanoparticles in the environment as well as those in nanomaterials developed for biomedical applications. However, the safety and biologic effects of many nanoparticles remain to be elucidated. Over the past decade, our understanding of the interaction of proteins with various nanomaterials has grown. The protein corona can determine not only how nanoparticles interact with cells but also their biologic effects and toxicity. In this study, we describe the effects that several different classes of nanoparticles exert on the enzymatic activity of the cytosolic protein human arylamine N-acetyltransferase 1 (NAT1), a drug-metabolizing enzyme widely distributed in the body that is also responsible for the activation and detoxification of known carcinogens. We investigated three metal oxides (zinc oxide, titanium dioxide, and silicon dioxide), two synthetic clay nanoparticles (layered double hydroxide and layered silicate nanoparticles), and a self-assembling thermoresponsive polymeric nanoparticle that differ in size and surface characteristics. We found that the different nanoparticles induced very different responses, ranging from inhibition to marked enhancement of enzyme activity. The layered silicates did not directly inactivate NAT1, but was found to enhance substrate-dependent inhibition. These differing effects demonstrate the multiplicity of nanoparticle-protein interactions and suggest that enzyme activity may be compromised in organs exposed to nanoparticles, such as the lungs or reticulo-endothelial system. Copyrigh

Inhibition of MEK1 increases HCV replication.

<p>Huh7.5.1 cells were transfected with a MEK1-specific siRNA (A) or treated with 10 µM PD98059 (B) and 6 hr post-transfection or treatment, infected with JFH-1 (MOI 0.02). 3 days post-infection, the expression of the HCV core protein was detected using western blot.</p

Up-regulation of DR4 and DR5 is HCV replication-dependent.

<p>(A) Lysates from Huh7, 9–13 and HCV-cured cells were subjected to western blot analysis using rabbit polyclonal antibodies against HCV NS3/4A, DR4 or DR5. (B) Huh7, 9–13 and HCV-cured cells were treated with 25 and 50 ng/mL TRAIL for 2 hr, and the proportion of apoptotic cells was measured using flow cytometry after the cells were stained with annexin V and PI. The data are presented with the SD from three independent experiments, and statistical significance was calculated by two-way ANOVA, * indicates a <i>p</i> value less than 0.05.</p

Low-Temperature Growth of Two-Dimensional Layered Chalcogenide Crystals on Liquid

The growth of high-quality two-dimensional (2D) layered chalcogenide crystals is highly important for practical applications in future electronics, optoelectronics, and photonics. Current route for the synthesis of 2D chalcogenide crystals by vapor deposition method mainly involves an energy intensive high-temperature growth process on solid substrates, often suffering from inhomogeneous nucleation density and grain size distribution. Here, we first demonstrate a facile vapor-phase synthesis of large-area high-quality 2D layered chalcogenide crystals on liquid metal surface with relatively low surface energy at a growth temperature as low as ∼100 °C. Uniform and large-domain-sized 2D crystals of GaSe and Ga_<i>x</i>In_1–<i>x</i>Se were grown on liquid metal surface even supported on a polyimide film. As-grown 2D GaSe crystals have been fabricated to flexible photodetectors, showing high photoresponse and excellent flexibility. Our strategy of energy-sustainable low-temperature growth on liquid metal surface may open a route to the synthesis of high-quality 2D crystals of Ga-, In-, Bi-, Hg-, Pb-, or Sn-based chalcogenides and halides

HCV replication up-regulates DR4 and DR5.

<p>(A) The mRNA level of DR4, DR5, DcR1, and DcR2 in 9–13 and Huh7 cells was measured using real-time RT-PCR. (B) Huh7 and 9–13 cell lysates were subjected to western blot analyses using a rabbit polyclonal antibody against DR4 or DR5. (C) The DR4 reporter plasmid (DR4/−1156; 100 ng) or DR5 reporter plasmid (DR5/−1192; 100 ng) was co-transfected with the <i>Renilla</i> luciferase reporter plasmid (100 ng) into 9–13 or Huh7 cells cultured in a 24-well plate. After 2 days, the cells were harvested, and the luciferase activity was measured. (A and C) The data from the 9–13 cells were normalized to Huh7 cells to directly show the fold induction caused by HCV. The data are presented with the SD from three independent experiments, and statistical significance was calculated by <i>t</i> test, * indicates a <i>p</i> value less than 0.05.</p

Transcriptional analysis of DR4 and DR5 in 9–13 cells.

<p>(A and C) Luciferase reporter plasmids (100 ng) containing different regions of the (A) DR4 or (C) DR5 promoter and the <i>Renilla</i> luciferase reporter plasmid (100 ng) were co-transfected into 9–13 or Huh7 cells. 2 days post-transfection, the cells were harvested, and luciferase activity was measured. (B and D) The indicated reporter plasmids (100 ng) illustrated in (E) were co-transfected with the <i>Renilla</i> luciferase reporter plasmid (100 ng) into 9–13 cells. 2 days post-transfection, the cells were harvested, and the luciferase activity was measured. (E) The mutations introduced into the AP-1 binding sites in pDR4/−632 and Sp1-binding sites in pDR5/−560 are illustrated. (F) The Sp1-specific siRNA or the control siRNA (100 pmol) was transfected into 9–13 cells cultured in 6-well plates. 2 days post-transfection, the Sp1 and DR5 RNA and protein levels were measured using real-time PCR and western blot analyses, respectively. (G) A plasmid expressing HCV NS3/4A, NS4B, NS5A or NS5B (600 ng) was individually co-transfected with either DR4/−632 or DR5/−560 (100 ng) and the <i>Renilla</i> luciferase reporter plasmid (100 ng) into Huh7 cells. 2 days post-transfection, the cells were harvested, and luciferase activity was measured. The data are presented with the SD from three independent experiments, and statistical significance was calculated by <i>t</i> test or two-way ANOVA, * indicates a <i>p</i> value less than 0.05.</p