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  • 1
    Publication Date: 2018-05-15
    Description: H7N9 virus has caused five infection waves since it emerged in 2013. The highest number of human cases was seen in wave 5; however, the underlying reasons have not been thoroughly elucidated. In this study, the geographical distribution, phylogeny, and genetic evolution of 240 H7N9 viruses in wave 5, including 35 new isolates from patients and poultry in nine provinces, were comprehensively analyzed together with strains from first four waves. Geographical distribution analysis indicated that the newly emerging highly pathogenic (HP) and low-pathogenicity (LP) H7N9 viruses were cocirculating, causing human and poultry infections across China. Genetic analysis indicated that dynamic reassortment of the internal genes among LP-H7N9/H9N2/H6Ny and HP-H7N9, as well as of the surface genes, between the Yangtze and Pearl River Delta lineages resulted in at least 36 genotypes, with three major genotypes (G1 [A/chicken/Jiangsu/SC537/2013-like], G3 [A/Chicken/Zhongshan/ZS/2017-like], and G11 [A/Anhui/40094/2015-like]). The HP-H7N9 genotype likely evolved from G1 LP-H7N9 by the insertion of a KRTA motif at the cleavage site (CS) and then evolved into 15 genotypes with four different CS motifs, including PKG KRTA R/G, PKG KRIA R/G, PKR KRAA R/G, and PKR KRTA R/G. Approximately 46% (28/61) of HP strains belonged to G3. Importantly, neuraminidase (NA) inhibitor (NAI) resistance (R292K in NA) and mammalian adaptation (e.g., E627K and A588V in PB2) mutations were found in a few non-human-derived HP-H7N9 strains. In summary, the enhanced prevalence and diverse genetic characteristics that occurred with mammalian-adapted and NAI-resistant mutations may have contributed to increased numbers of human infections in wave 5. IMPORTANCE The highest numbers of human H7N9 infections were observed during wave 5 from October 2016 to September 2017. Our results showed that HP-H7N9 and LP-H7N9 had spread virtually throughout China and underwent dynamic reassortment with different subtypes (H7N9/H9N2 and H6Ny) and lineages (Yangtze and Pearl River Delta lineages), resulting in totals of 36 and 3 major genotypes, respectively. Notably, the NAI drug-resistant (R292K in NA) and mammalian-adapted (e.g., E627K in PB2) mutations were found in HP-H7N9 not only from human isolates but also from poultry and environmental isolates, indicating increased risks for human infections. The broad dissemination of LP- and HP-H7N9 with high levels of genetic diversity and host adaptation and drug-resistant mutations likely accounted for the sharp increases in the number of human infections during wave 5. Therefore, more strategies are needed against the further spread and damage of H7N9 in the world.
    Print ISSN: 0022-538X
    Electronic ISSN: 1098-5514
    Topics: Medicine
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  • 2
    Publication Date: 2018-03-06
    Description: Tumor-associated macrophages (TAMs) are pivotal effector cells in angiogenesis. Here, we tested whether CYP4X1 inhibition in TAMs by flavonoid CH625 prolongs survival and normalizes glioma vasculature. CH625 was selected against the CYP4X1 3D model by virtual screening and showed inhibitory activity on the CYP4X1 catalytic production of 14,15-EET-EA in the M2-polarized human peripheral blood mononuclear cells (IC 50 = 16.5 μ M). CH625 improved survival and reduced tumor burden in the C6 and GL261 glioma intracranial and subcutaneous model. In addition, CH625 normalized vasculature (evidenced by a decrease in microvessel density and HIF-1 α expression and an increase in tumor perfusion, pericyte coverage, and efficacy of temozolomide therapy) accompanied with the decreased secretion of 14,15-EET-EA, VEGF, and TGF- β in the TAMs. Furthermore, CH625 attenuated vascular abnormalization and immunosuppression induced by coimplantation of GL261 cells with CYP4X1 high macrophages. In vitro TAM polarization away from the M2 phenotype by CH625 inhibited proliferation and migration of endothelial cells, enhanced pericyte migration and T cell proliferation, and decreased VEGF and TGF- β production accompanied with the downregulation of CB2 and EGFR-dependent downstream STAT3 expression. These effects were reversed by overexpression of CYP4X1 and STAT3 or exogenous addition of 14,15-EET-EA, VEGF, TGF- β , EGF, and CB2 inhibitor AM630. These results suggest that CYP4X1 inhibition in TAMs by CH625 prolongs survival and normalizes tumor vasculature in glioma via CB2 and EGFR-STAT3 axis and may serve as a novel therapeutic strategy for human glioma.
    Print ISSN: 0022-3565
    Electronic ISSN: 1521-0103
    Topics: Medicine
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  • 3
    Publication Date: 2018-09-05
    Description: Background: Telomere dysfunction triggers cellular senescence and constitutes a driving force for cancer initiation. Genetic variants in genes involved in telomere maintenance may contribute to colorectal cancer susceptibility. Methods: In this study, we firstly captured germline mutations in 192 patients with colorectal cancer by sequencing the coding regions of 13 core components implicated in telomere biology. Five potential functional variants were then genotyped and assessed in a case–control set with 3,761 colorectal cancer cases and 3,839 healthy controls. The promising association was replicated in additional 6,765 cases and 6,906 controls. Functional experiments were used to further clarify the potential function of the significant variant and uncover the underlying mechanism in colorectal cancer development. Results: The two-stage association studies showed that a rare missense variant rs149418249 (c. C 1520 T and p.P507L) in the 11th exon of TPP1 (also known as ACD , gene ID 65057) was significantly associated with colorectal cancer risk with the ORs being 2.90 [95% confidence interval (CI), 1.04–8.07; P = 0.041], 2.50 (95% CI, 1.04–6.04; P = 0.042), and 2.66 (95% CI, 1.36–5.18; P = 0.004) in discovery, replication, and the combined samples, respectively. Further functional annotation indicated that the TPP1 P507L substitution interrupted TPP1–TIN2 interaction, impaired telomerase processivity, and shortened telomere length, which subsequently facilitated cell proliferation and promoted colorectal cancer development. Conclusions: A rare variant P507L in TPP1 confers increased risk of colorectal cancer through interrupting TPP1–TIN2 interaction, impairing telomerase processivity, and shrinking telomere length. Impact: These findings emphasize the important role of telomere dysfunction in colorectal cancer development, and provide new insights about the prevention of this type of cancer. Cancer Epidemiol Biomarkers Prev; 27(9); 1029–35. ©2018 AACR .
    Print ISSN: 1055-9965
    Electronic ISSN: 1538-7755
    Topics: Medicine
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  • 4
    Publication Date: 2018-09-15
    Description: Purpose: Deletions or mutations in PTEN and TP53 tumor suppressor genes have been linked to lineage plasticity in therapy-resistant prostate cancer. Fusion-driven overexpression of the oncogenic transcription factor ERG is observed in approximately 50% of all prostate cancers, many of which also harbor PTEN and TP53 alterations. However, the role of ERG in lineage plasticity of PTEN / TP53 –altered tumors is unclear. Understanding the collective effect of multiple mutations within one tumor is essential to combat plasticity-driven therapy resistance. Experimental Design: We generated a Pten -negative/ Trp53 -mutated/ ERG -overexpressing mouse model of prostate cancer and integrated RNA-sequencing with ERG chromatin immunoprecipitation-sequencing (ChIP-seq) to identify pathways regulated by ERG in the context of Pten / Trp53 alteration. We investigated ERG-dependent sensitivity to the antiandrogen enzalutamide and cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor palbociclib in human prostate cancer cell lines, xenografts, and allografted mouse tumors. Trends were evaluated in TCGA, SU2C, and Beltran 2016 published patient cohorts and a human tissue microarray. Results: Transgenic ERG expression in mice blocked Pten / Trp53 alteration–induced decrease of AR expression and downstream luminal epithelial genes. ERG directly suppressed expression of cell cycle–related genes, which induced RB hypophosphorylation and repressed E2F1-mediated expression of mesenchymal lineage regulators, thereby restricting adenocarcinoma plasticity and maintaining antiandrogen sensitivity. In ERG-negative tumors, CDK4/6 inhibition delayed tumor growth. Conclusions: Our studies identify a previously undefined function of ERG to restrict lineage plasticity and maintain antiandrogen sensitivity in PTEN / TP53 –altered prostate cancer. Our findings suggest ERG fusion as a biomarker to guide treatment of PTEN / TP53 -altered, RB1 -intact prostate cancer. Clin Cancer Res; 24(18); 4551–65. ©2018 AACR .
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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  • 5
    Publication Date: 2018-12-04
    Description: Hepatocellular carcinoma (HCC) is one of the most common and deadly human cancers. The 5-year survival rate is very low. Unfortunately, there are few efficacious therapeutic options. Until recently, Sorafenib has been the only available systemic drug for advanced HCC. However, it has very limited survival benefits, and new therapies are urgently needed. In this study, we investigated the anti-HCC activity of carfilzomib, a second-generation, irreversible proteasome inhibitor, as a single agent and in combination with sorafenib. In vitro , we found that carfilzomib has moderate anticancer activity toward liver cancer cells, but strongly enhances the ability of sorafenib to suppress HCC cell growth, proliferation, migration, invasion, and survival. Remarkably, the drug combination exhibits even more potent antitumor activity when tested in animal tumor models. Mechanistically, the combined treatment activates caspase-dependent and endoplasmic reticulum stress/CHOP-mediated apoptotic pathways, and suppresses epithelial–mesenchymal transition. In conclusion, our results demonstrate that the combination of carfilzomib and sorafenib has synergistic antitumor activities against HCC, providing a potential therapeutic strategy to improve the mortality and morbidity of HCC patients.
    Print ISSN: 1535-7163
    Electronic ISSN: 1538-8514
    Topics: Medicine
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  • 6
    Publication Date: 2018-12-01
    Description: The structure of dispersed vanadyl species plays a crucial role in the selective catalytic reduction (SCR) of NO with NH 3 over vanadia-based catalysts. Here, we demonstrate that the polymeric vanadyl species have a markedly higher NH 3 -SCR activity than the monomeric vanadyl species. The coupling effect of the polymeric structure not only shortens the reaction pathway for the regeneration of redox sites but also substantially reduces the overall reaction barrier of the catalytic cycle. Therefore, it is the polymeric vanadyl species, rather than the monomeric vanadyl species, that determine the NH 3 -SCR activity of vanadia-based catalysts, especially under low-temperature conditions. The polymeric vanadia-based SCR mechanism reported here advances the understanding of the working principle of vanadia-based catalysts and paves the way toward the development of low vanadium–loading SCR catalysts with excellent low-temperature activity.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 7
    Publication Date: 2018-05-17
    Description: This study aims to investigate the effect of consolidation shear stress magnitude on the shear behaviour and non-coaxiality of soils. In previous drained bi-directional simple shear test on Leighton Buzzard sand, it is showed that the level of non-coaxiality, which is indicated by the angle difference between the principal axes of stresses and the corresponding principal axes of strain rate tensors, is increased by increasing angle difference between the direction of consolidation shear stress and secondary shearing. This paper further investigated the relation and includes results with higher consolidation shear stresses. Results agree with the previous relation, and further showed that increasing consolidation shear stresses decreased the level of non-coaxiality in tests with angle difference between 0° and 90°, and increased the level of non-coaxiality in tests with angle difference between 90° and 180°.
    Keywords: civil engineering, engineering geology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 8
    Publication Date: 2018-03-31
    Description: Objective We aim to synthesise up-to-date randomised trials to investigate the effects of levosimendan on mortality and clinical outcomes in severe sepsis and septic shock. Methods A collection of databases including PubMed, EMBASE, Cochrane Central Register and Web of Science were searched updated to August 2017. Randomised trials were included when they pertain to the use of levosimendan in severe sepsis or septic shock compared with any category of inotropes, or as an adjunct to standard therapy with mortality reported. The primary outcome was mortality, and the secondary outcomes were clinical performances including serum lactate, cardiac function, vasopressor requirement and fluid infusion. Results A total of 10 studies with 1036 patients were included in this meta-analysis. The results revealed that levosimendan could not reduce mortality significantly in severe sepsis and septic shock (OR 0.89, 95% CI 0.69 to 1.16, P=0.39). Levosimendan use could reduce serum lactate more effectively, and enhance cardiac contractibility with increased cardiac index and left ventricular ejection fraction. However, its use could also increase fluid infusion but not reduce norepinephrine dose. No significant benefit in mortality could be observed of levosimendan versus dobutamine use, or in patients with proven cardiac dysfunction. Conclusions Current evidence is not sufficient to support levosimendan as superior to dobutamine or as an optimal adjunct in severe sepsis and septic shock. More large-scale randomised trials are necessary to validate levosimendan use in sepsis.
    Keywords: Open access, Intensive care
    Electronic ISSN: 2044-6055
    Topics: Medicine
    Published by BMJ Publishing
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  • 9
    Publication Date: 2018-03-16
    Description: Osteocalcin has recently been shown to regulate energy homeostasis through multiple pathways. Adipose tissue is a main organ of energy metabolism, and administration of recombinant osteocalcin in mice promoted energy consumption, thus counteracting obesity and glucose intolerance. The regulation of osteocalcin in islet β cells has been well documented; however, it is unknown whether osteocalcin can also act on adipocytes and, if it does, how it functions. Here, we provide evidence to demonstrate a specific role for osteocalcin in brown adipocyte thermogenesis. Importantly, expression of the Gprc6a gene encoding a G protein-coupled receptor as an osteocalcin receptor was activated by brown fat-like differentiation. Moreover, Gprc6a expression could be further potentiated by osteocalcin. Meanwhile, overexpression and knockdown experiments validated the crucial role of Gprc6a in osteocalcin-mediated activation of thermogenic genes. For the first time, we identified Tcf7 and Wnt3a as putative targets for osteocalcin signaling. T cell factor 7 (TCF7) belongs to the TCF/LEF1 family of DNA binding factors crucial for the canonical WNT/β-catenin pathway; however, TCF7 modulates Gprc6a and Ucp1 promoter activation independent of β-catenin. Further studies revealed that the thermogenesis coactivator PRDM16 and the histone demethylase LSD1 might be required for TCF7 activity. Hence, our study described a TCF7-dependent feedback control of the osteocalcin-GPRC6A axis in brown adipocyte physiologies.
    Print ISSN: 0270-7306
    Electronic ISSN: 1098-5549
    Topics: Biology , Medicine
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  • 10
    Publication Date: 2018-01-31
    Description: Coronavirus spike proteins from different genera are divergent, although they all mediate coronavirus entry into cells by binding to host receptors and fusing viral and cell membranes. Here, we determined the cryo-electron microscopy structure of porcine deltacoronavirus (PdCoV) spike protein at 3.3-Å resolution. The trimeric protein contains three receptor-binding S1 subunits that tightly pack into a crown-like structure and three membrane fusion S2 subunits that form a stalk. Each S1 subunit contains two domains, an N-terminal domain (S1-NTD) and C-terminal domain (S1-CTD). PdCoV S1-NTD has the same structural fold as alpha- and betacoronavirus S1-NTDs as well as host galectins, and it recognizes sugar as its potential receptor. PdCoV S1-CTD has the same structural fold as alphacoronavirus S1-CTDs, but its structure differs from that of betacoronavirus S1-CTDs. PdCoV S1-CTD binds to an unidentified receptor on host cell surfaces. PdCoV S2 is locked in the prefusion conformation by structural restraint of S1 from a different monomeric subunit. PdCoV spike possesses several structural features that may facilitate immune evasion by the virus, such as its compact structure, concealed receptor-binding sites, and shielded critical epitopes. Overall, this study reveals that deltacoronavirus spikes are structurally and evolutionally more closely related to alphacoronavirus spikes than to betacoronavirus spikes; it also has implications for the receptor recognition, membrane fusion, and immune evasion by deltacoronaviruses as well as coronaviruses in general. IMPORTANCE In this study, we determined the cryo-electron microscopy structure of porcine deltacoronavirus (PdCoV) spike protein at a 3.3-Å resolution. This is the first atomic structure of a spike protein from the deltacoronavirus genus, which is divergent in amino acid sequences from the well-studied alpha- and betacoronavirus spike proteins. Here, we described the overall structure of the PdCoV spike and the detailed structure of each of its structural elements. Moreover, we analyzed the functions of each of the structural elements. Based on the structures and functions of these structural elements, we discussed the evolution of PdCoV spike protein in relation to the spike proteins from other coronavirus genera. This study combines the structure, function, and evolution of PdCoV spike protein and provides many insights into its receptor recognition, membrane fusion, and immune evasion.
    Print ISSN: 0022-538X
    Electronic ISSN: 1098-5514
    Topics: Medicine
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