bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of G-Protein-Coupled and -Uncoupled CCR5 Receptors by CCR5 Inhibitor-Resistant and -Sensitive Human Immunodeficiency Virus Type 1 Variants
Authors: Berro Reem , Yasmeen Anila , Abrol Ravinder , Trzaskowski Bartosz , Abi-Habib Sarya , Grunbeck Amy , Lascano Danny , Goddard William A. , Klasse Per Johan , Sakmar Thomas P. , Moore John P. 
Published: March 2013

ABSTRACT

Small-molecule CCR5 inhibitors such as vicriviroc (VVC) and maraviroc (MVC) are allosteric modulators that impair HIV-1 entry by stabilizing a CCR5 conformation that the virus recognizes inefficiently. Viruses resistant to these compounds are able to bind the inhibitor-CCR5 complex while also interacting with the free coreceptor. CCR5 also interacts intracellularly with G proteins, as part of its signal transduction functions, and this process alters its conformation. Here we investigated whether the action of VVC against inhibitor-sensitive and -resistant viruses is affected by whether or not CCR5 is coupled to G proteins such as Gα
i
. Treating CD4
+
T cells with pertussis toxin to uncouple the Gα
i
subunit from CCR5 increased the potency of VVC against the sensitive viruses and revealed that VVC-resistant viruses use the inhibitor-bound form of Gα
i
-coupled CCR5 more efficiently than they use uncoupled CCR5. Supportive evidence was obtained by expressing a signaling-deficient CCR5 mutant with an impaired ability to bind to G proteins, as well as two constitutively active mutants that activate G proteins in the absence of external stimuli. The implication of these various studies is that the association of intracellular domains of CCR5 with the signaling machinery affects the conformation of the external and transmembrane domains and how they interact with small-molecule inhibitors of HIV-1 entry.
Characterization of Virus-Encoded RNA Interference Suppressors in Caenorhabditis elegans
Authors: Guo Xunyang , Lu Rui 
Published: March 2013

ABSTRACT

In fungi, plants, and invertebrates, antiviral RNA interference (RNAi) directed by virus-derived small interfering RNAs (siRNAs) represents a major antiviral defense that the invading viruses have to overcome in order to establish infection. As a counterdefense mechanism, viruses of these hosts produce diverse classes of proteins capable of suppressing the biogenesis and/or function of viral siRNAs. This RNA-directed viral immunity (RDVI) in the nematode
Caenorhabditis elegans
is known to exhibit some unique features. Currently, little is known about viral suppression of RNAi in
C. elegans
. Here, we show that ectopic expression of the B2 protein encoded by Flock House virus (FHV) suppresses RNAi induced by either long double-stranded RNA (dsRNA) or an FHV-based replicon and facilitates the natural infection of
C. elegans
by Orsay virus but is not active against RNA silencing mediated by microRNAs. We report the development of an assay for the identification of viral suppressor of RNAi (VSR) in
C. elegans
based on the suppression of a viral replicon-triggered RDVI by ectopic expression of candidate proteins. No VSR activity was detected for either of the two Orsay viral proteins proposed previously as VSRs. We detected, among the known heterologous VSRs, VSR activity for B2 of Nodamura virus but not for 2b of tomato aspermy virus, p29 of fungus-infecting hypovirus, or p19 of tomato bushy stunt virus. We further show that, unlike that in plants and insects, FHV B2 suppresses worm RDVI mainly by interfering with the function of virus-derived primary siRNAs.
Human Papillomaviruses Modulate MicroRNA 145 Expression To Directly Control Genome Amplification
Authors: Gunasekharan Vignesh , Laimins Laimonis A. 
Published: March 2013

ABSTRACT
Human papillomaviruses (HPVs) modulate expression of host microRNAs. Our deep-sequencing analysis of organotypic raft cultures identified microRNA 145 (miR-145) as a differentiation-dependent microRNA that has functionally active target sequences in the HPV-31 E1 and E2 open reading frames. Overexpression of miR-145 in HPV-positive cells resulted in reduced genome amplification and late gene expression, along with decreased levels of cellular transcription factor KLF-4. Our studies show that HPV modulates miR-145 expression to control its own life cycle.
Structure of Schmallenberg Orthobunyavirus Nucleoprotein Suggests a Novel Mechanism of Genome Encapsidation
Authors: Dong Haohao , Li Ping , Elliott Richard M. , Dong Changjiang 
Published: March 2013

ABSTRACT

Schmallenberg virus (SBV), a newly emerged orthobunyavirus (family
Bunyaviridae
), has spread rapidly across Europe and has caused congenital abnormalities in the offspring of cattle, sheep, and goats. Like other orthobunyaviruses, SBV contains a tripartite negative-sense RNA genome that encodes four structural and two nonstructural proteins. The nucleoprotein (N) encapsidates the three viral genomic RNA segments and plays a crucial role in viral RNA transcription and replication. Here we report the crystal structure of the bacterially expressed SBV nucleoprotein to a 3.06-Å resolution. The protomer is composed of two domains (N-terminal and C-terminal domains) with flexible N-terminal and C-terminal arms. The N protein has a novel fold and forms a central positively charged cleft for genomic RNA binding. The nucleoprotein purified under native conditions forms a tetramer, while the nucleoprotein obtained following denaturation and refolding forms a hexamer. Our structural and functional analyses demonstrate that both N-terminal and C-terminal arms are involved in N-N interaction and oligomerization and play an essential role in viral RNA synthesis, suggesting a novel mechanism for viral RNA encapsidation and transcription.
Characterization of a New World Monopartite Begomovirus Causing Leaf Curl Disease of Tomato in Ecuador and Peru Reveals a New Direction in Geminivirus Evolution
Authors: Melgarejo Tomas A. , Kon Tatsuya , Rojas Maria R. , Paz-Carrasco Lenin , Zerbini F. Murilo , Gilbertson Robert L. 
Published: March 2013

ABSTRACT

All characterized whitefly-transmitted geminiviruses (begomoviruses) with origins in the New World (NW) have bipartite genomes composed of a DNA-A and DNA-B component. Recently, an NW begomovirus lacking a DNA-B component was associated with tomato leaf curl disease (ToLCD) in Peru, and it was named Tomato leaf deformation virus (ToLDeV). Here, we show that isolates of ToLDeV associated with ToLCD in Ecuador and Peru have a single, genetically diverse genomic DNA that is most closely related to DNA-A components of NW bipartite begomoviruses. Agroinoculation of multimeric clones of the genomic DNA of three ToLDeV genotypes (two variants and a strain) resulted in the development of tomato leaf curl symptoms indistinguishable from those of ToLCD in Ecuador and Peru. Biological properties of these ToLDeV genotypes were similar to those of Old World (OW) monopartite tomato-infecting begomoviruses, including lack of sap transmissibility, phloem limitation, a resistance phenotype in tomato germplasm with the
Ty-1
gene, and functional properties of the V1 (capsid protein) and C4 genes. Differences in symptom phenotypes induced by the ToLDeV genotypes in tomato and
Nicotiana benthamiana
plants were associated with a highly divergent left intergenic region and C4 gene. Together, these results establish that ToLDeV is an emergent NW monopartite begomovirus that is causing ToLCD in Ecuador and Peru. This is the first report of an indigenous NW monopartite begomovirus, and evidence is presented that it emerged from the DNA-A component of a NW bipartite progenitor via convergent evolution and recombination.
A Cluster of Virus-Encoded MicroRNAs Accelerates Acute Systemic Epstein-Barr Virus Infection but Does Not Significantly Enhance Virus-Induced Oncogenesis
In Vivo
Authors: Wahl Angela , Linnstaedt Sarah D. , Esoda Caitlin , Krisko John F. , Martinez-Torres Francisco , Delecluse Henri-Jacques , Cullen Bryan R. , Garcia J. Victor 
Published: March 2013

ABSTRACT

Over 90% of the adult human population is chronically infected with the Epstein-Barr virus (EBV), an oncogenic herpesvirus. EBV primarily infects naive human B cells and persists latently in memory B cells. Most individuals experience an asymptomatic infection that is effectively controlled by the adaptive immune response. However, EBV-associated lymphomas can develop in immunocompromised individuals. These tumors typically express all nine EBV latent proteins (latency III). Latency III is also associated with the expression of three precursor microRNAs (miRNAs) located within the EBV BHRF1 gene locus. The role of these BHRF1 miRNAs was unclear until recent
in vitro
studies demonstrated that they cooperate to enhance virus-induced B cell transformation and decrease the antigenic load of virus-infected cells, indicating that the BHRF1 miRNA cluster may serve as a novel therapeutic target for the treatment of latency III EBV-associated malignancies. However, to date, it is not known if BHRF1 miRNAs enhance virus-induced oncogenesis and/or immune evasion of EBV
in vivo
. To understand the
in vivo
contribution of the BHRF1 miRNA cluster to EBV infection and EBV-associated tumorigenesis, we monitored EBV infection and assessed tumor formation in humanized mice exposed to wild-type virus and a viral mutant (Δ123) that lacks all three BHRF1 miRNAs. Our results demonstrate that while the BHRF1 miRNAs facilitate the development of acute systemic EBV infection, they do not enhance the overall oncogenic potential of EBV
in vivo
.
Structural Features of a Picornavirus Polymerase Involved in the Polyadenylation of Viral RNA
Authors: Kempf Brian J. , Kelly Michelle M. , Springer Courtney L. , Peersen Olve B. , Barton David J. 
Published: March 2013

ABSTRACT

Picornaviruses have 3′ polyadenylated RNA genomes, but the mechanisms by which these genomes are polyadenylated during viral replication remain obscure. Based on prior studies, we proposed a model wherein the poliovirus RNA-dependent RNA polymerase (3D
pol
) uses a reiterative transcription mechanism while replicating the poly(A) and poly(U) portions of viral RNA templates. To further test this model, we examined whether mutations in 3D
pol
influenced the polyadenylation of virion RNA. We identified nine alanine substitution mutations in 3D
pol
that resulted in shorter or longer 3′ poly(A) tails in virion RNA. These mutations could disrupt structural features of 3D
pol
required for the recruitment of a cellular poly(A) polymerase; however, the structural orientation of these residues suggests a direct role of 3D
pol
in the polyadenylation of RNA genomes. Reaction mixtures containing purified 3D
pol
and a template RNA with a defined poly(U) sequence provided data consistent with a template-dependent reiterative transcription mechanism for polyadenylation. The phylogenetically conserved structural features of 3D
pol
involved in the polyadenylation of virion RNA include a thumb domain alpha helix that is positioned in the minor groove of the double-stranded RNA product and lysine and arginine residues that interact with the phosphates of both the RNA template and product strands.
Human MicroRNA hsa-miR-296-5p Suppresses Enterovirus 71 Replication by Targeting the Viral Genome
Authors: Zheng Zhenhua , Ke Xianliang , Wang Meng , He Siyi , Li Qian , Zheng Caishang , Zhang Zhenfeng , Liu Yan , Wang Hanzhong 
Published: March 2013

ABSTRACT

Enterovirus 71 (EV71) has emerged as a major cause of neurological disease following the near eradication of poliovirus. Accumulating evidence suggests that mammalian microRNAs (miRNAs), a class of noncoding RNAs of 18 to 23 nucleotides (nt) with important regulatory roles in many cellular processes, participate in host antiviral defenses. However, the roles of miRNAs in EV71 infection and pathogenesis are still unclear. Here, hsa-miR-296-5p expression was significantly increased in EV71-infected human cells. As determined by virus titration, quantitative real-time PCR (qRT-PCR), and Western blotting, overexpression of hsa-miR-296-5p inhibited, while inhibition of endogenous hsa-miR-296-5p facilitated, EV71 infection. Additionally, two potential hsa-miR-296-5p targets (nt 2115 to 2135 and nt 2896 to 2920) located in the EV71 genome (strain BrCr) were bioinformatically predicted and validated by luciferase reporter assays and Western blotting. Genomic alignment of various EV71 strains revealed synonymous mutations in hsa-miR-296-5p target sequences. Furthermore, the introduction of synonymous mutations into the EV71 BrCr genome by site-directed mutagenesis impaired the viral inhibitory effects of hsa-miR-296-5p and facilitated mutant virus infection. Meanwhile, compensatory mutations in corresponding hsa-miR-296-5p target sequences of the EV71 HeN strain (GenBank accession number
JN256064
) restored the inhibitory effects of the miRNA. These results indicate that hsa-miR-296-5p inhibits EV71 replication by targeting the viral genome. Our findings support the notion that cellular miRNAs can inhibit virus infection and that the virus mutates to escape suppression by cellular miRNAs.
Venezuelan Equine Encephalitis Replicon Particles Can Induce Rapid Protection against Foot-and-Mouth Disease Virus
Authors: Diaz-San Segundo Fayna , Dias Camila C. A. , Moraes Mauro P. , Weiss Marcelo , Perez-Martin Eva , Owens Gary , Custer Max , Kamrud Kurt , de los Santos Teresa , Grubman Marvin J. 
Published: March 2013

ABSTRACTWe have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach to induce rapid protection against FMDV, we have examined the ability of VRPs containing either the gene for green fluorescent protein (VRP-GFP) or poIFN-α (VRP-poIFN-α) to block FMDV replicationin vitroandin vivo. Pretreatment of swine or bovine cell lines with either VRP significantly inhibited subsequent infection with FMDV as early as 6 h after treatment and for at least 120 h posttreatment. Furthermore, mice pretreated with either 107or 108infectious units of VRP-GFP and challenged with a lethal dose of FMDV 24 h later were protected from death. Protection was induced as early as 6 h after treatment and lasted for at least 48 h and correlated with induction of an antiviral response and production of IFN-α. By 6 h after treatment several genes were upregulated, and the number of genes and the level of induction increased at 24 h. Finally, we demonstrated that the chemokine IP-10, which is induced by IFN-α and VRP-GFP, is directly involved in protection against FMDV.
Selective decontamination of the digestive tract and selective oropharyngeal decontamination in intensive care unit patients: a cost-effectiveness analysis
Authors: Oostdijk Evelien A N , de Wit G A , Bakker Marina , de Smet Anne Marie G A , Bonten M J M 
Published: March 2013

ObjectiveTo determine costs and effects of selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) as compared with standard care (ie, no SDD/SOD (SC)) from a healthcare perspective in Dutch Intensive Care Units (ICUs).DesignA post hoc analysis of a previously performed cluster-randomised trial (NEJM2009;360:20).Setting13 Dutch ICUs.ParticipantsPatients with ICU-stay of >48 h that received SDD (n=2045), SOD (n=1904) or SC (n=1990).InterventionsSDD or SOD.Primary and secondary outcome measuresEffects were based on hospital survival, expressed as crude Life Years Gained (cLYG). The incremental cost-effectiveness ratio (ICER) was calculated, with corresponding cost acceptability curves. Sensitivity analyses were performed for discount rates, costs of SDD, SOD and mechanical ventilation.ResultsTotal costs per patient were €41 941 for SC (95% CI €40 184 to €43 698), €40 433 for SOD (95% CI €38 838 to €42 029) and €41 183 for SOD (95% CI €39 408 to €42 958). SOD and SDD resulted in crude LYG of +0.04 and +0.25, respectively, as compared with SC, implying that both SDD and SOD are dominant (ie, cheaper and more beneficial) over SC. In cost-effectiveness acceptability curves probabilities for cost-effectiveness, compared with standard care, ranged from 89% to 93% for SOD and from 63% to 72% for SDD, for acceptable costs for 1 LYG ranging from €0 to €20 000. Sensitivity analysis for mechanical ventilation and discount rates did not change interpretation. Yet, if costs of the topical component of SDD and SOD would increase 40-fold to €400/day and €40/day (maximum values based on free market prices in 2012), the estimated ICER as compared with SC for SDD would be €21 590 per LYG. SOD would remain cost-saving.ConclusionsSDD and SOD were both effective and cost-saving in Dutch ICUs.
Medical students' subjective ratings of stress levels and awareness of student support services about mental health
Authors: Walter Garry , Soh Nerissa Li-Wey , Norgren Jaconelli Sanna , Lampe Lisa , Malhi Gin S , Hunt Glenn 
Published: March 2013

Abstract

Purpose
To descriptively assess medical students' concerns for their mental and emotional state, perceived need to conceal mental problems, perceived level of support at university, knowledge and use of student support services, and experience of stresses of daily life.

Study design
From March to September 2011, medical students at an Australian university were invited to complete an anonymous online survey.

Results
475 responses were received. Students rated study and examinations (48.9%), financial concerns (38.1%), isolation (19.4%) and relationship concerns (19.2%) as very or extremely stressful issues. Knowledge of available support services was high, with 90.8% indicating they were aware of the university's medical centre. Treatment rates were modest (31.7%). Students' concerns about their mental state were generally low, but one in five strongly felt they needed to conceal their emotional problems.

Conclusions
Despite widespread awareness of appropriate support services, a large proportion of students felt they needed to conceal mental and emotional problems. Overall treatment rates for students who were greatly concerned about their mental and emotional state appeared modest, and, although comparable with those of similarly aged community populations, may reflect undertreatment. It would be appropriate for universities to address stressors identified by students. Strategies for encouraging distressed students to obtain appropriate assessment and treatment should also be explored. Those students who do seek healthcare are most likely to see a primary care physician, suggesting an important screening role for these health professionals.
Downregulation of Hepatoma-Derived Growth Factor Contributes to Retarded Lung Metastasis via Inhibition of Epithelial–Mesenchymal Transition by Systemic POMC Gene Delivery in Melanoma
Authors: Tsai Han-En , Liu Guei-Sheung , Kung Mei-Lang , Liu Li-Feng , Wu Jian-Ching , Tang Chia-Hua , Huang Ching-Hui , Chen San-Cher , Lam Hing-Chung , Wu Chieh-Shan , Tai Ming-Hong 
Published: March 2013

Abstract
The prognosis of malignant melanoma is poor due to high incidence of metastasis, underscoring the demand for development of novel therapeutic strategies. Stress hormone pro-opiomelanocortin (POMC) is the precursor for several anti-inflammatory peptides that hold promise for management of cancer-related diseases. The present study evaluated the antimetastatic potential and mechanism of POMC therapy for metastatic melanoma. Adenovirus-mediated POMC gene delivery potently inhibited the invasiveness of human and mouse melanoma cells. Moreover, after induction of lung metastasis, systemic POMC expression significantly reduced the foci formation and neovascularization in lungs. Mechanistic studies revealed that POMC therapy inhibited the epithelial–mesenchymal transition (EMT) of melanoma cells by upregulation of E-cadherin and downregulation of vimentin and α-smooth muscle actin (α-SMA). In addition, microarray analysis unveiled POMC gene transfer reduced the mRNA level of multiple prometastatic factors, including hepatoma-derived growth factor (HDGF). Cell culture and immunohistochemical studies further confirmed that POMC gene delivery significantly decreased the expression of HDGF in melanoma cells and tissues. Despite stimulating the invasion and EMT, exogenous HDGF supply only partially attenuated the POMC-mediated invasion inhibition and EMT change in melanoma cells. Finally, we delineated the contribution of melanocortins to POMC-induced inhibition of invasion, HDGF downregulation, and E-cadherin upregulation. Together, these results indicate that HDGF downregulation participates in POMC-induced suppression of metastasis and EMT in melanoma. Mol Cancer Ther; 12(6); 1016–25. ©2013 AACR.
mda-7/IL-24 Expression Inhibits Breast Cancer through Upregulation of Growth Arrest-Specific Gene 3 (gas3) and Disruption of β1 Integrin Function
Authors: Li You-Jun , Liu Guodong , Li Yanmei , Vecchiarelli-Federico Laura M. , Liu Jeff C. , Zacksenhaus Eldad , Shan Sze W. , Yang Burton B. , Li Qi , Dash Rupesh , Fisher Paul B. , Archer Michael C. , Ben-David Yaacov 
Published: March 2013

Abstract
Melanoma differentiation-associated gene (MDA)-7)/interleukin (IL)-24, a member of the IL-10 family of cytokines, inhibits growth of various human cancer cells, yet the underlying mechanism is largely unknown. Here, we report that mda-7/IL-24 efficiently suppresses the development of rat mammary tumors in vivo. Microarray analysis for genes differentially expressed in rat mammary tumor cells overexpressing MDA-7/IL-24 compared with those that do not express this cytokine identified growth arrest-specific gene-3 (gas3) as a target for mda-7/IL-24. Upregulation of gas3 by mda-7/IL-24 was STAT3 dependent. Induction of gas3 inhibited attachment and proliferation of tumor cells in vitro and in vivo by inhibiting the interaction of β1 integrin with fibronectin. A mutated GAS3, which is unable to bind β1 integrin, was also unable to inhibit fibronectin-mediated attachment and cell growth both in adherent and suspension cultures, suggesting that GAS3 exerts its effects through interaction with and regulation of β1 integrin. Thus, mda-7/IL-24 inhibits breast cancer growth, at least in part, through upregulation of GAS3 and disruption of β1 integrin function. Importantly, the expression of the mda-7/IL-24 receptor, IL-20R1, is highly correlated with GAS3 expression in human breast cancer (P = 1.02 × 10−9), and the incidence of metastases is significantly reduced in patients with HER2+ breast cancer expressing high-levels of IL-20R1. Together, our results identify a novel MDA-7/IL-24-GAS3-β1integrin–fibronectin signaling pathway that suppresses breast cancer growth and can be targeted for therapy. Mol Cancer Res; 11(6); 593–603. ©2013 AACR.