Apolipoprotein e mediates attachment of clinical hepatitis C virus to hepatocytes by binding to cell surface heparan sulfate proteoglycan receptors

Our previous studies demonstrated that the cell culture-grown hepatitis C virus of genotype 2a (HCVcc) uses apolipoprotein E (apoE) to mediate its attachment to the surface of human hepatoma Huh-7.5 cells. ApoE mediates HCV attachment by binding to the cell surface heparan sulfate (HS) which is covalently attached to the core proteins of proteoglycans (HSPGs). In the present study, we further determined the physiological importance of apoE and HSPGs in the HCV attachment using a clinical HCV of genotype 1b (HCV1b) obtained from hepatitis C patients and human embryonic stem cell-differentiated hepatocyte-like cells (DHHs). DHHs were found to resemble primary human hepatocytes. Similar to HCVcc, HCV1b was found to attach to the surface of DHHs by the apoE-mediated binding to the cell surface HSPGs. The apoE-specific monoclonal antibody, purified HSPGs, and heparin were all able to efficiently block HCV1b attachment to DHHs. Similarly, the removal of heparan sulfate from cell surface by treatment with heparinase suppressed HCV1b attachment to DHHs. More significantly, HCV1b attachment was potently inhibited by a synthetic peptide derived from the apoE receptor-binding region as well as by an HSPG-binding peptide. Likewise, the HSPG-binding peptide prevented apoE from binding to heparin in a dose-dependent manner, as determined by an in vitro heparin pull-down assay. Collectively, these findings demonstrate that HSPGs serve as major HCV attachment receptors on the surface of human hepatocytes to which the apoE protein ligand on the HCV envelope binds

Large-scale thrusting at the northern Junggar Basin since Cretaceous and its implications for the rejuvenation of the Central Asian Orogenic Belt

The Wulungu Depression is the northernmost first-order tectonic unit in the Junggar Basin. It can be divided into three sub-units: the Hongyan step-fault zone, the Suosuoquan sag and the Wulungu south slope. The Cenozoic strata in the basin are intact and Mesozoic–Cenozoic deformation can be observed in the Wulungu step-fault zone, so this is an ideal place to study the Mesozoic–Cenozoic deformation. By integration of fault-related folding theories, regional geology and drilling data, the strata of the Cretaceous–Paleogene systems are divided into small layers which are selected as the subjects of this research. The combination of the developing unconformity with existing growth strata makes it conceivable that faults on the step-fault zone have experienced different degrees of reactivation of movement since the Cretaceous. Evolutionary analyses of the small layers using 2D-Move software showed certain differences in the reactivation of different segments of the Wulungu Depression such as the timing of reactivation of thrusting, for which the reactivity time of the eastern segment was late compared with those of the western and middle segments. In addition the resurrection strength was similarly slightly different, with the shortening rate being higher in the western segment than in the other segments. Moreover, the thrust fault mechanism is basement-involved combined with triangle shear fold, for which a forward evolution model was proposed

Kinematics of syn-tectonic unconformities and implications for the tectonic evolution of the Hala'alat Mountains at the northwestern margin of the Junggar Basin, Central Asian Orogenic Belt

AbstractThe Hala'alat Mountains are located at the transition between the West Junggar and the Junggar Basin. In this area, rocks are Carboniferous, with younger strata above them that have been identified through well data and high-resolution 3D seismic profiles. Among these strata, seven unconformities are observed and distributed at the bases of: the Permian Jiamuhe Formation, the Permian Fengcheng Formation, the Triassic Baikouquan Formation, the Jurassic Badaowan Formation, the Jurassic Xishanyao Formation, the Cretaceous Tugulu Group and the Paleogene. On the basis of balanced sections, these unconformities are determined to have been formed by erosion of uplifts or rotated fault blocks primarily during the Mesozoic and Cenozoic. In conjunction with the currently understood tectonic background of the surrounding areas, the following conclusions are proposed: the unconformities at the bases of the Permian Jiamuhe and Fengcheng formations are most likely related to the subduction and closure of the Junggar Ocean during the late Carboniferous–early Permian; the unconformities at the bases of the Triassic Baikouquan and Jurassic Badaowan formations are closely related to the late Permian–Triassic Durbut sinistral slip fault; the unconformities at the bases of the middle Jurassic Xishanyao Formation and Cretaceous Tugulu Group may be related to reactivation of the Durbut dextral slip fault in the late Jurassic–early Cretaceous, and the unconformity that gives rise to the widely observed absence of the upper Cretaceous in the northern Junggar Basin may be closely related to large scale uplift. All of these geological phenomena indicate that the West Junggar was not calm in the Mesozoic and Cenozoic and that it experienced at least four periods of tectonic movement

A Review of the Metallogenic Mechanisms of Sandstone-Type Uranium Deposits in Hydrocarbon-Bearing Basins in China

As a valuable mineral resource, uranium is extensively utilized in nuclear power generation, radiation therapy, isotope labeling, and tracing. In order to achieve energy structure diversification, reduce dependence on traditional fossil fuels, and promote the sustainable development of energy production and consumption, research on the metallogenic mechanisms and related development technologies of uranium resources has been one of the focuses of China’s energy development. Sandstone-type uranium deposits make up approximately 43% of all deposits in China, making them the most prevalent form of uranium deposit there. Sandstone-type uranium deposits and hydrocarbon resources frequently coexist in the same basin in China. Therefore, this study summarizes the spatial and chronological distribution, as well as the geological characteristics, of typical sandstone-type uranium deposits in China’s hydrocarbon-bearing basins. From the perspectives of fluid action, geological structure, and sedimentary environment, the metallogenic mechanisms of sandstone-type uranium deposits in hydrocarbon-bearing basins are explored. According to the research, the rapid reduction effect of oil and gas in the same basin is a major factor in the generation of relatively large uranium deposits. Additionally, ions such as CO32− and HCO3− in hydrothermal fluids of hydrocarbon-bearing basins, which typically originate from dispersed oil and gas, are more conducive to uranium enrichment and sedimentation. This study provides guidance for efficient sandstone-type uranium deposit exploration and production in hydrocarbon-bearing basins and helps to achieve significant improvements in uranium resource exploitation efficiency

Detection of QTL for High-Temperature Tolerance in Rice Using a High-Density Bin Map

Rice is sensitive to high-temperature stress during almost all stages of growth and development. High-temperature stress has become one of the main factors restricting high yield and superior quality of rice. In this study, recombinant inbred lines (RILs) derived from an indica rice cross between two restorer lines were planted in two years. One sowing date was applied in 2019, and four sowing dates were set in 2020 according to the period of local high temperatures in recent years. Two traits closely related to high-temperature tolerance, heading date (HD), and spikelet fertility (SF) were measured. In each trial, the HD showed a bimodal distribution, whereas SF had a continuous and left-skewed distribution. QTL analysis was performed using a high-density bin map. For HD, a total of six QTL were detected. All of them correspond in position to the cloned genes, among which qHD8 in the DTH8/Ghd8 region showed the largest genetic effect. For SF, a total of eight QTL were detected. Five of them, qSF1, qSF2, qSF3.1, qSF3.2, and qSF8, showed high-temperature tolerance and had an important potential in rice breeding

Effects of the apoE-derived peptides and the HSPG-binding peptide 6a-P on heparin binding.

<p>Heparin-immobilized beads (Pierce) were pre-equilibrated with PBS and then incubated with 500 µl of Huh-7.5 cell culture medium in the absence or presence of varying concentrations of the peptide hEP or 6a-P. The mutant peptides hEPm and 6a-Pm were used as controls. After 2 hrs incubation at room temperature, apoE-bound heparin-immobilized beads were spun down by centrifugation. The supernatant was collected and used for detection of the unbound apoE. The apoE-bound beads in pellet were washed three times with 1 ml of PBS. The heparin-bound and unbound apoE proteins were measured by Western blotting using an apoE-specific monoclonal antibody (WuE4).</p

Inhibition of HCV1b attachment to DHHs by purified HSPG (A) and Heparin (B).

<p>The HCV1b was pre-incubated with varying amounts of HSPG or Heparin for 1 hr on ice prior to adding to day-11 DHHs in 12-well cell culture plates as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067982#s2" target="_blank">materials and methods</a>. After incubation on ice for 2 hrs, the unbound HCV was removed by washing cells with PBS for three times. The vRNA of the cell-bound HCV was extracted with Trizol reagent (Invitrogen). The levels of HCV1b vRNA were determined using the same real-time RT-qPCR method as in Fig. 1.</p

Effect of heparinase treatment on HCV1b attachment to DHHs.

<p>The day-11 DHHs in 12-well cell culture plates were incubated with varying concentrations of heparinase I in a buffer containing 20 mM Tris-HCl (pH 6.8), 50 mM NaCl, 4 mM CaCl₂ and 0.01% bovine serum albumin at 37°C for 1 hr <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067982#pone.0067982-Koutsoudakis1" target="_blank">[18]</a>. The heparinase-treated DHHs were then incubated with HCV1b on ice for 2 hrs. The unbound HCV was removed and the cells were washed with 1x PBS for three times. The HCV1b vRNA of the cell-bound HCV was extracted with Trizol reagent and quantified by RT-qPCR using the StepOnePlus real-time PCR system same as that in Fig. 1.</p

Blockade of HCV1b cell attachment by apoE monoclonal antibody mAb23.

<p>DHHs at day-11 were incubated with HCV1b in the absence (Control) or presence of 10 µg/ml of normal mouse IgG1 (mIgG1) or increasing amounts of apoE mAb23 (0.4, 2, and 10 µg/ml) at 37°C for 2 hrs. The unbound HCV was removed by washing cells with 1x PBS for three times. The vRNA of the cell-bound HCV was extracted with Trizol reagent (Invitrogen). The levels of HCV vRNA were quantified by a real-time RT-PCR method using SuperScript® III Platinum® SYBR® Green One-Step qPCR Kit (Invitrogen). Reactions were run in a StepOnePlus real-time PCR system (Applied Biosystems) using the conditions provided by the qPCR kit. A house-keeping gene GAPDH was used as an internal control, which was quantified using Hu-GAPDH primer/probe mix containing vic-TAMRA (Applied Biosystems). The levels of HCV vRNA were calculated from the average data of three experiments upon normalization with the level of GAPDH.</p