bluuebunny/crossref_metadata_2025_split huggingface dataset:
Caspase Inhibition Protects against Reovirus-Induced Myocardial Injury In Vitro and In Vivo
Authors: DeBiasi Roberta L. , Robinson Bridget A. , Sherry Barbara , Bouchard Ron , Brown R. Dale , Rizeq Mona , Long Carlin , Tyler Kenneth L. 
Published: September 2004

ABSTRACT
Viral myocarditis is a disease with a high morbidity and mortality. The pathogenesis of this disease remains poorly characterized, with components of both direct virus-mediated and secondary inflammatory and immune responses contributing to disease. Apoptosis has increasingly been viewed as an important mechanism of myocardial injury in noninfectious models of cardiac disease, including ischemia and failure. Using a reovirus murine model of viral myocarditis, we characterized and targeted apoptosis as a key mechanism of virus-associated myocardial injury in vitro and in vivo. We demonstrated caspase-3 activation, in conjunction with terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling and annexin binding, in cardiac myocytes after myocarditic viral infection in vitro. We also demonstrated a tight temporal and geographical correlation between caspase-3 activation, histologic injury, and viral load in cardiac tissue after myocarditic viral infection in vivo. Two pharmacologic agents that broadly inhibit caspase activity, Q-VD-OPH and Z-VAD(OMe)-FMK, effectively inhibited virus-induced cellular death in vitro. The inhibition of caspase activity in vivo by the use of pharmacologic agents as well as genetic manipulation reduced virus-induced myocardial injury by 40 to 60% and dramatically improved survival in infected caspase-3-deficient animals. This study indicates that apoptosis plays a critical role in mediating cardiac injury in the setting of viral myocarditis and is the first demonstration that caspase inhibition may serve as a novel therapeutic strategy for this devastating disease.
Identification of Differentially Expressed Genes in Scrapie-Infected Mouse Brains by Using Global Gene Expression Technology
Authors: Xiang Wei , Windl Otto , Wünsch Gerda , Dugas Martin , Kohlmann Alexander , Dierkes Nicola , Westner Ingo M. , Kretzschmar Hans A. 
Published: September 2004

ABSTRACTThe pathogenesis of prion diseases, a class of transmissible fatal neurodegenerative diseases in humans and animals, is still unclear. The aim of this study was to identify the differentially regulated genes that correlate with the development of prion diseases for a better understanding of their pathological mechanisms. We employed Affymetrix Mouse Expression Arrays 430A containing >22,000 transcripts and compared the global gene expression profiles from brains of mice who were intracerebrally inoculated with scrapie strains ME7 and RML with those from brains of uninfected and mock-infected mice. The microarray data were analyzed by Significance Analysis of Microarrays, revealing 121 genes whose expression increased at least twofold in both ME7- and RML-infected mouse brains, with an estimated false discovery rate of ≤5%. These genes encode proteins involved in proteolysis, protease inhibition, cell growth and maintenance, the immune response, signal transduction, cell adhesion, and molecular metabolism. The time course of expression generally showed up-regulation of these genes from 120 days postinoculation (dpi) for ME7-inoculated mouse brains and from 90 dpi for RML-inoculated mouse brains. The onset of elevated expression correlated temporally with the onset of PrPScaccumulation and the activation of glia, which may have contributed to neuronal cell death. Among the differentially regulated genes reported in the present study, the emergence of genes for several cathepsins and S100 calcium binding proteins was conspicuous. These and other genes reported here may represent novel potential diagnostic and therapeutic targets for prion disease.
APOBEC3G
Genetic Variants and Their Influence on the Progression to AIDS
Authors: An Ping , Bleiber Gabriela , Duggal Priya , Nelson George , May Margaret , Mangeat Bastien , Alobwede Irene , Trono Didier , Vlahov David , Donfield Sharyne , Goedert James J. , Phair John , Buchbinder Susan , O'Brien Stephen J. , Telenti Amalio , Winkler Cheryl A. 
Published: September 2004

ABSTRACT

The cytosine deaminase APOBEC3G, in the absence of the human immunodeficiency virus type 1 (HIV-1) accessory gene HIV-1 viral infectivity factor (
vif
), inhibits viral replication by introducing G→A hypermutation in the newly synthesized HIV-1 DNA negative strand. We tested the hypothesis that genetic variants of
APOBEC3G
may modify HIV-1 transmission and disease progression. Single nucleotide polymorphisms were identified in the promoter region (three), introns (two), and exons (two). Genotypes were determined for 3,073 study participants enrolled in six HIV-AIDS prospective cohorts. One codon-changing variant, H186R in exon 4, was polymorphic in African Americans (AA) (
f
= 37%) and rare in European Americans (
f
< 3%) or Europeans (
f
= 5%). For AA, the variant allele 186R was strongly associated with decline in CD4 T cells (CD4 slope on square root scale: −1.86,
P
= 0.009), The 186R allele was also associated with accelerated progression to AIDS-defining conditions in AA. The in vitro antiviral activity of the 186R enzyme was not inferior to that of the common H186 variant. These studies suggest that there may be a modifying role of variants of
APOBEC3G
on HIV-1 disease progression that warrants further investigation.
Repression of Human T-Cell Leukemia Virus Type 1 and Type 2 Replication by a Viral mRNA-Encoded Posttranscriptional Regulator
Authors: Younis Ihab , Khair Lyne , Dundr Miroslav , Lairmore Michael D. , Franchini Genoveffa , Green Patrick L. 
Published: September 2004

ABSTRACT

Human T-cell leukemia virus type 1 (HTLV-1) and HTLV-2 are complex retroviruses that persist in the host, eventually causing leukemia and neurological disease in a small percentage of infected individuals. In addition to structural and enzymatic proteins, HTLV encodes regulatory (Tax and Rex) and accessory (open reading frame I and II) proteins. The viral Tax and Rex proteins positively regulate virus production. Tax activates viral and cellular transcription to promote T-cell growth and, ultimately, malignant transformation. Rex acts posttranscriptionally to facilitate cytoplasmic expression of viral mRNAs that encode the structural and enzymatic gene products, thus positively controlling virion expression. Here, we report that both HTLV-1 and HTLV-2 have evolved accessory genes to encode proteins that act as negative regulators of both Tax and Rex. HTLV-1 p30
II
and the related HTLV-2 p28
II
inhibit virion production by binding to and retaining
tax/rex
mRNA in the nucleus. Reduction of viral replication in a cell carrying the provirus may allow escape from immune recognition in an infected individual. These data are consistent with the critical role of these proteins in viral persistence and pathogenesis in animal models of HTLV-1 and HTLV-2 infection.
Avian Reovirus Temperature-Sensitive Mutant
tsA12
Has a Lesion in Major Core Protein σA and Is Defective in Assembly
Authors: Xu Wanhong , Patrick Megan K. , Hazelton Paul R. , Coombs Kevin M. 
Published: September 2004

ABSTRACT

Members of our laboratory previously generated and described a set of avian reovirus (ARV) temperature-sensitive (
ts
) mutants and assigned 11 of them to 7 of the 10 expected recombination groups, named A through G (M. Patrick, R. Duncan, and K. M. Coombs, Virology
284:
113-122, 2001). This report presents a more detailed analysis of two of these mutants (
tsA12
and
tsA146
), which were previously assigned to recombination group A. The capacities of
tsA12
and
tsA146
to replicate at a variety of temperatures were determined. Morphological analyses indicated that cells infected with
tsA12
at a nonpermissive temperature produced ∼100-fold fewer particles than cells infected at a permissive temperature and accumulated core particles. Cells infected with
tsA146
at a nonpermissive temperature also produced ∼100-fold fewer particles, a larger proportion of which were intact virions. We crossed
tsA12
with ARV strain 176 to generate reassortant clones and used them to map the temperature-sensitive lesion in
tsA12
to the S2 gene. S2 encodes the major core protein σA. Sequence analysis of the
tsA12
S2 gene showed a single alteration, a cytosine-to-uracil transition, at nucleotide position 488. This alteration leads to a predicted amino acid change from proline to leucine at amino acid position 158 in the σA protein. An analysis of the core crystal structure of the closely related mammalian reovirus suggested that the Leu
158
substitution in ARV σA lies directly under the outer face of the σA protein. This may cause a perturbation in σA such that outer capsid proteins are incapable of condensing onto nascent cores. Thus, the ARV
tsA12
mutant represents a novel assembly-defective orthoreovirus clone that may prove useful for delineating virus assembly.
Multiple V1/V2
env
Variants Are Frequently Present during Primary Infection with Human Immunodeficiency Virus Type 1
Authors: Ritola Kimberly , Pilcher Christopher D. , Fiscus Susan A. , Hoffman Noah G. , Nelson Julie A. E. , Kitrinos Kathryn M. , Hicks Charles B. , Eron Joseph J. , Swanstrom Ronald 
Published: September 2004

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) exists as a complex population of multiple genotypic variants in persons with chronic infection. However, acute HIV-1 infection via sexual transmission is a low-probability event in which there is thought to be low genetic complexity in the initial inoculum. In order to assess the viral complexity present during primary HIV-1 infection, the V1/V2 and V3 variable regions of the
env
gene were examined by using a heteroduplex tracking assay (HTA) capable of resolving these genotypic variants. Blood plasma samples from 26 primary HIV-1-infected subjects were analyzed for their level of diversity. Half of the subjects had more than one V1/V2 viral variant during primary infection, indicating the frequent transmission of multiple variants. This observation is inconsistent with the idea of infrequent transmission based on a small transmitting inoculum of cell-free virus. In chronically infected subjects, the complexity of the viral populations was even greater in both the V1/V2 and the V3 regions than in acutely infected subjects, indicating that in spite of the presence of multiple variants in acute infection, the virus does pass through a genetic bottleneck during transmission. We also examined how well the infecting virus penetrated different anatomical compartments by using the HTA. Viral variants detected in blood plasma were compared to those detected in seminal plasma and/or cerebral spinal fluid of six individuals. The virus in each of these compartments was to a large extent identical to virus in blood plasma, a finding consistent with rapid penetration of the infecting variant(s). The low-probability transmission of multiple variants could be the result of transient periods of hyperinfectiousness or hypersusceptibility. Alternatively, the inefficient transfer of a multiply infected cell could account for both the low probability of transmission and the transfer of multiple variants.
Evidence for Gene Expression by Unintegrated Human Immunodeficiency Virus Type 1 DNA Species
Authors: Brussel Audrey , Sonigo Pierre 
Published: September 2004

ABSTRACTThe integrated form of human immunodeficiency virus type 1 (HIV-1) DNA is classically considered to be the sole template for viral gene expression. However, several studies have suggested that unintegrated viral DNA species could also support transcription. To determine the contribution of the different species of HIV-1 DNA to viral expression, we first monitored intracellular levels of various HIV-1 DNA and RNA species in a single-round infection assay. We observed that, in comparison to the precocity of HIV-1 DNA synthesis, viral expression was delayed, suggesting that only the HIV-1 DNA species that persist for a sufficient period of time would be transcribed efficiently. We next evaluated the transcriptional activity of the circular forms of HIV-1 DNA bearing two long terminal repeats, since these episomes were reported to exhibit an intrinsic molecular stability. Our results support the notion that these circular species of HIV-1 DNA are naturally transcribed during HIV-1 infection, thereby participating in virus replication.
Protective Efficacy of a DNA Influenza Virus Vaccine Is Markedly Increased by the Coadministration of a Schiff Base-Forming Drug
Authors: Charo Jehad , Lindencrona Jan Alvar , Carlson Lena-Maria , Hinkula Jorma , Kiessling Rolf 
Published: September 2004

ABSTRACTEffective vaccination against heterologous influenza virus infection remains elusive. Immunization with plasmid DNA (pDNA) expressing conserved genes from influenza virus is a promising approach to achieve cross-variant protection. However, despite having been described for more than a decade, pDNA vaccination still requires further optimization to be applied clinically as a standard vaccination approach. We have recently described a simple and efficient approach to enhance pDNA immunization, based on the use of tucaresol, a Schiff base-forming drug. In this report we have tested the ability of this drug to increase the protection conferred by pDNA vaccination against influenza virus infection. Our results demonstrate that a significant protection was achieved in two strains of mice by using the combination of pDNA and tucaresol. This protection was associated with an elevated humoral and cellular response and a switch in the type of the T helper cell (Th) immune response from type 2 to type 1. This vaccine combination represents a promising strategy for designing a clinical study for the protection from influenza and similar infections.
Transient Immunosuppression Stops Rejection of Virus-Transduced Enhanced Green Fluorescent Protein in Rabbit Retina
Authors: Doi Kentaro , Kong Jian , Hargitai Janos , Goff Stephen P. , Gouras Peter 
Published: September 2004

ABSTRACT
The expression of lentivirus-transduced enhanced green fluorescent protein (EGFP) was detectable in rabbit retinal pigment epithelium (RPE) within 3 to 5 days after subretinal injection of the vector. Within 2 to 3 weeks, EGFP-expressing cells were eliminated by rejection. In the current experiments, we monitor serum antibody titers for EGFP before and after transduction and determine whether systemic immunosuppression prevents recognition of EGFP by the immune system. While all control rabbits developed antibodies against EFGP and showed signs of rejection, no such evidence was observed with animals which received immunosuppression. One month of systemic immunosuppression permanently prevented rejection of RPE with EGFP expression. Fluorescence has been maintained for more than a year. If a control eye was injected with the same virus after terminating immunosuppression, both eyes showed signs of rejection. The lack of rejection is not due to tolerance but to a failure of the animals to detect the foreign protein. Detection must depend upon a brief window of time after surgery needed to introduce the vector, perhaps related to a concurrent but transient inflammation. This strategy may be useful in managing other types of rejection in the retina.
Predicting the Impact of a Nonsterilizing Vaccine against Human Immunodeficiency Virus
Authors: Davenport Miles P. , Ribeiro Ruy M. , Chao Dennis L. , Perelson Alan S. 
Published: September 2004

ABSTRACTStudies of human immunodeficiency virus (HIV) vaccines in animal models suggest that it is difficult to induce complete protection from infection (sterilizing immunity) but that it is possible to reduce the viral load and to slow or prevent disease progression following infection. We have developed an age-structured epidemiological model of the effects of a disease-modifying HIV vaccine that incorporates the intrahost dynamics of infection, a transmission rate and host mortality that depend on the viral load, the possible evolution and transmission of vaccine escape mutant viruses, a finite duration of vaccine protection, and possible changes in sexual behavior. Using this model, we investigated the long-term outcome of a disease-modifying vaccine and utilized uncertainty analysis to quantify the effects of our lack of precise knowledge of various parameters. Our results suggest that the extent of viral load reduction in vaccinated infected individuals (compared to unvaccinated individuals) is the key predictor of vaccine efficacy. Reductions in viral load of about 1 log10copies ml−1would be sufficient to significantly reduce HIV-associated mortality in the first 20 years after the introduction of vaccination. Changes in sexual risk behavior also had a strong impact on the epidemic outcome. The impact of vaccination is dependent on the population in which it is used, with disease-modifying vaccines predicted to have the most impact in areas of low prevalence and rapid epidemic growth. Surprisingly, the extent to which vaccination alters disease progression, the rate of generation of escape mutants, and the transmission of escape mutants are predicted to have only a weak impact on the epidemic outcome over the first 25 years after the introduction of a vaccine.
Genomic and Proteomic Analysis of Thirty-Nine Structural Proteins of Shrimp White Spot Syndrome Virus
Authors: Tsai Jyh-Ming , Wang Han-Ching , Leu Jiann-Horng , Hsiao He-Hsuan , Wang Andrew H.-J. , Kou Guang-Hsiung , Lo Chu-Fang 
Published: September 2004

ABSTRACT

White spot syndrome virus (WSSV) virions were purified from the hemolymph of experimentally infected crayfish
Procambarus clarkii
, and their proteins were separated by 8 to 18% gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to give a protein profile. The visible bands were then excised from the gel, and following trypsin digestion of the reduced and alkylated WSSV proteins in the bands, the peptide sequence of each fragment was determined by liquid chromatography-nano-electrospray ionization tandem mass spectrometry (LC-nanoESI-MS/MS) using a quadrupole/time-of-flight mass spectrometer. Comparison of the resulting peptide sequence data against the nonredundant database at the National Center for Biotechnology Information identified 33 WSSV structural genes, 20 of which are reported here for the first time. Since there were six other known WSSV structural proteins that could not be identified from the SDS-PAGE bands, there must therefore be a total of at least 39 (33 + 6) WSSV structural protein genes. Only 61.5% of the WSSV structural genes have a polyadenylation signal, and preliminary analysis by 3′ rapid amplification of cDNA ends suggested that some structural protein genes produced mRNA without a poly(A) tail. Microarray analysis showed that gene expression started at 2, 6, 8, 12, 18, 24, and 36 hpi for 7, 1, 4, 12, 9, 5, and 1 of the genes, respectively. Based on similarities in their time course expression patterns, a clustering algorithm was used to group the WSSV structural genes into four clusters. Genes that putatively had common or similar roles in the viral infection cycle tended to appear in the same cluster.
Heterologous RNA Encapsidated in Pariacoto Virus-Like Particles Forms a Dodecahedral Cage Similar to Genomic RNA in Wild-Type Virions
Authors: Johnson Karyn N. , Tang Liang , Johnson John E. , Ball L. Andrew 
Published: September 2004

ABSTRACT
The genome of some icosahedral RNA viruses plays an essential role in capsid assembly and structure. In T=3 particles of the nodavirus Pariacoto virus (PaV), a remarkable 35% of the single-stranded RNA genome is icosahedrally ordered. This ordered RNA can be visualized at high resolution by X-ray crystallography as a dodecahedral cage consisting of 30 24-nucleotide A-form RNA duplex segments that each underlie a twofold icosahedral axis of the virus particle and interact extensively with the basic N-terminal region of 60 subunits of the capsid protein. To examine whether the PaV genome is a specific determinant of the RNA structure, we produced virus-like particles (VLPs) by expressing the wild-type capsid protein open reading frame from a recombinant baculovirus. VLPs produced by this system encapsidated similar total amounts of RNA as authentic virus particles, but only about 6% of this RNA was PaV specific, the rest being of cellular or baculovirus origin. Examination of the VLPs by electron cryomicroscopy and image reconstruction at 15.4-Å resolution showed that the encapsidated RNA formed a dodecahedral cage similar to that of wild-type particles. These results demonstrate that the specific nucleotide sequence of the PaV genome is not required to form the dodecahedral cage of ordered RNA.
An N-Terminal Amphipathic Helix in Hepatitis C Virus (HCV) NS4B Mediates Membrane Association, Correct Localization of Replication Complex Proteins, and HCV RNA Replication
Authors: Elazar Menashe , Liu Ping , Rice Charles M. , Glenn Jeffrey S. 
Published: September 2004

ABSTRACT
Like other positive-strand RNA viruses, hepatitis C virus (HCV) is believed to replicate its RNA in association with host cell cytoplasmic membranes. Because of its association with such membranes, NS4B, one of the virus's nonstructural proteins, may play an important role in this process, although the mechanistic details are not well understood. We identified a putative N-terminal amphipathic helix (AH) in NS4B that mediates membrane association. Introduction of site-directed mutations designed to disrupt the hydrophobic face of the AH abolishes the AH's ability to mediate membrane association. An AH in NS4B is conserved across HCV isolates. Completely disrupting the amphipathic nature of NS4B's N-terminal helix abolished HCV RNA replication, whereas partial disruption resulted in an intermediate level of replication. Finally, immunofluorescence studies revealed that HCV replication complex components were mislocalized in the AH-disrupted mutant. These results identify a key membrane-targeting domain which can form the basis for developing novel antiviral strategies.
Macaque Model for Severe Acute Respiratory Syndrome
Authors: Rowe Thomas , Gao Guangping , Hogan Robert J. , Crystal Ronald G. , Voss Thomas G. , Grant Rebecca L. , Bell Peter , Kobinger Gary P. , Wivel Nelson A. , Wilson James M. 
Published: September 2004

ABSTRACT

Rhesus and cynomolgus macaques were challenged with 10
7
PFU of a clinical isolate of the severe acute respiratory syndrome (SARS) coronavirus. Some of the animals developed a mild self-limited respiratory infection very different from that observed in humans with SARS. The macaque model as it currently exists will have limited utility in the study of SARS and the evaluation of therapies.
Persistent Infection with Primate Foamy Virus Type 1 Increases Human Immunodeficiency Virus Type 1 Cell Binding via a Bet-Independent Mechanism
Authors: Schiffer Cecile , Lecellier Charles-Henri , Mannioui Abdelkrim , Felix Nathalie , Nelson Elisabeth , Lehmann-Che Jacqueline , Giron Marie-Louise , Gluckman Jean Claude , Saib Ali , Canque Bruno 
Published: September 2004

ABSTRACTWe report that human T cells persistently infected with primate foamy virus type 1 (PFV-1) display an increased capacity to bind human immunodeficiency virus type 1 (HIV-1), resulting in increased cell permissiveness to HIV-1 infection and enhanced cell-to-cell virus transmission. This phenomenon is independent of HIV-1 receptor, CD4, and it is not related to PFV-1 Bet protein expression. Increased virus attachment is specifically inhibited by heparin, indicating that it should be mediated by interactions with heparan sulfate glycosaminoglycans expressed on the target cells. Given that both viruses infect similar animal species, the issue of whether coinfection with primate foamy viruses interferes with the natural course of lentivirus infections in nonhuman primates should be considered.