bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visualizing the Beta Interferon Response in Mice during Infection with Influenza A Viruses Expressing or Lacking Nonstructural Protein 1
Authors: Kallfass Carsten , Lienenklaus Stefan , Weiss Siegfried , Staeheli Peter 
Published: April 2013

ABSTRACT

The innate host defense against influenza virus is largely dependent on the type I interferon (IFN) system. However, surprisingly little is known about the cellular source of IFN in the infected lung. To clarify this question, we employed a reporter mouse that contains the firefly luciferase gene in place of the IFN-β-coding region. IFN-β-producing cells were identified either by simultaneous immunostaining of lungs for luciferase and cellular markers or by generating conditional reporter mice that express luciferase exclusively in defined cell types. Two different strains of influenza A virus were employed that either do or do not code for nonstructural protein 1 (NS1), which strongly suppresses innate immune responses of infected cells. We found that epithelial cells and lung macrophages, which represent the prime host cells for influenza viruses, showed vigorous IFN-β responses which, however, were severely reduced and delayed if the infecting virus was able to produce NS1. Interestingly, CD11c
+
cell populations that were either expressing or lacking macrophage markers produced the bulk of IFN-β at 48 h after infection with wild-type influenza A virus. Our results demonstrate that the virus-encoded IFN-antagonistic factor NS1 disarms specifically epithelial cells and lung macrophages, which otherwise would serve as main mediators of the early response against infection by influenza virus.
New Model for the Genesis and Maturation of Viroplasms Induced by Fijiviruses in Insect Vector Cells
Authors: Mao Qianzhuo , Zheng Shenglan , Han Qingmei , Chen Hongyan , Ma Yuanyuan , Jia Dongsheng , Chen Qian , Wei Taiyun 
Published: April 2013

ABSTRACT

Plant reoviruses are thought to replicate and assemble within cytoplasmic, nonmembranous structures called viroplasms. Here, we established continuous cell cultures of the white-backed planthopper (
Sogatella furcifera
Horváth) to investigate the mechanisms for the genesis and maturation of the viroplasm induced by Southern rice black-streaked dwarf virus (SRBSDV), a fijivirus in the family
Reoviridae
, during infection of its insect vector. Electron and confocal microscopy revealed that the viroplasm consisted of a granular region, where viral RNAs and nonstructural proteins P6 and P9-1 accumulated, and a filamentous region, where viral RNAs, progeny cores, viral particles, as well as nonstructural proteins P5 and P6 accumulated. Our results suggested that the filamentous viroplasm matrix was the site for the assembly of progeny virions. Because viral RNAs were produced by assembled core particles within the filamentous viroplasm matrix, we propose that these viral RNAs might be transported to the granular viroplasm matrix. P5 formed filamentous inclusions and P9-1 formed granular inclusions in the absence of viral infection, suggesting that the filamentous and granular viroplasm matrices were formed primarily by P5 and P9-1, respectively. P6 was apparently recruited in the whole viroplasm matrix by direct interaction with P9-1 and P5. Thus, the present results suggested that P5, P6, and P9-1 are collectively required for the genesis and maturation of the filamentous and granular viroplasm matrix induced by SRBSDV infection. Based on these results, we propose a new model to explain the genesis and maturation of the viroplasms induced by fijiviruses in insect vector cells.
Foot-and-Mouth Disease Virus Modulates Cellular Vimentin for Virus Survival
Authors: Gladue D. P. , O'Donnell V. , Baker-Branstetter R. , Holinka L. G. , Pacheco J. M. , Fernández Sainz I. , Lu Z. , Ambroggio X. , Rodriguez L. , Borca M. V. 
Published: April 2013

ABSTRACT

Foot-and-mouth disease virus (FMDV), the causative agent of foot-and-mouth disease, is an Aphthovirus within the
Picornaviridae
family. During infection with FMDV, several host cell membrane rearrangements occur to form sites of viral replication. FMDV protein 2C is part of the replication complex and thought to have multiple roles during virus replication. To better understand the role of 2C in the process of virus replication, we have been using a yeast two-hybrid approach to identify host proteins that interact with 2C. We recently reported that cellular Beclin1 is a natural ligand of 2C and that it is involved in the autophagy pathway, which was shown to be important for FMDV replication. Here, we report that cellular vimentin is also a specific host binding partner for 2C. The 2C-vimentin interaction was further confirmed by coimmunoprecipitation and immunofluorescence staining to occur in FMDV-infected cells. It was shown that upon infection a vimentin structure forms around 2C and that this structure is later resolved or disappears. Interestingly, overexpression of vimentin had no effect on virus replication; however, overexpression of a truncated dominant-negative form of vimentin resulted in a significant decrease in viral yield. Acrylamide, which causes disruption of vimentin filaments, also inhibited viral yield. Alanine scanning mutagenesis was used to map the specific amino acid residues in 2C critical for vimentin binding. Using reverse genetics, we identified 2C residues that are necessary for virus growth, suggesting that the interaction between FMDV 2C and cellular vimentin is essential for virus replication.
Rotavirus-Encoded Nonstructural Protein 1 Modulates Cellular Apoptotic Machinery by Targeting Tumor Suppressor Protein p53
Authors: Bhowmick Rahul , Halder Umesh Chandra , Chattopadhyay Shiladitya , Nayak Mukti Kant , Chawla-Sarkar Mamta 
Published: April 2013

ABSTRACT
p53, a member of the innate immune system, is triggered under stress to induce cell growth arrest and apoptosis. Thus, p53 is an important target for viruses, as efficient infection depends on modulation of the host apoptotic machinery. This study focuses on how rotaviruses manipulate intricate p53 signaling for their advantage. Analysis of p53 expression revealed degradation of p53 during initial stages of rotavirus infection. However, in nonstructural protein-1 (NSP1) mutant strain A5-16, p53 degradation was not observed, suggesting a role of NSP1 in this process. This function of NSP1 was independent of its interferon or phosphatidylinositol 3-kinase (PI3K)/AKT modulation activity since p53 degradation was observed in Vero cells as well as in the presence of PI3K inhibitor. p53 transcript levels remained the same in SA11-infected cells (at 2 to 14 h postinfection), but p53 protein was stabilized only in the presence of MG132, suggesting a posttranslational process. NSP1 interacted with the DNA binding domain of p53, resulting in ubiquitination and proteasomal degradation of p53. Degradation of p53 during initial stages of infection inhibited apoptosis, as the proapoptotic genes PUMA and Bax were downregulated. During late viral infection, when progeny dissemination is the main objective, the NSP1-p53 interaction was diminished, resulting in restoration of the p53 level, with initiation of proapoptotic signaling ensuing. Overall results highlight the multiple strategies evolved by NSP1 to combat the host immune response.
Sustained Hyperresponsiveness of Dendritic Cells Is Associated with Spontaneous Resolution of Acute Hepatitis C
Authors: Pelletier Sandy , Bédard Nathalie , Said Elias , Ancuta Petronela , Bruneau Julie , Shoukry Naglaa H. 
Published: April 2013

ABSTRACT

Some studies have reported that dendritic cells (DCs) may be dysfunctional in a subset of patients with chronic hepatitis C virus (HCV) infection. However, the function of DCs during acute HCV infection and their role in determining infectious outcome remain elusive. Here, we examined the phenotype and function of myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) during acute HCV infection. Three groups of injection drug users (IDUs) at high risk of HCV infection were studied: an uninfected group, a group with acute HCV infection with spontaneous resolution, and a group with acute infection with chronic evolution. We examined the frequency, maturation status, and cytokine production capacity of DCs in response to the Toll-like receptor 4 (TLR4) and TLR7/8 ligands lipopolysaccharide (LPS) and single-stranded RNA (ssRNA), respectively. Several observations could distinguish HCV-negative IDUs and acute HCV resolvers from patients with acute infection with chronic evolution. First, we observed a decrease in the frequency of mature CD86
+
, programmed death-1 receptor ligand-positive (PDL1
+
), and PDL2
+
pDCs. This phenotype was associated with the increased sensitivity of pDCs from resolvers and HCV-negative IDUs versus the group with acute infection with chronic evolution to ssRNA stimulation
in vitro
. Second, LPS-stimulated mDCs from resolvers and HCV-negative IDUs produced higher levels of cytokines than mDCs from the group with acute infection with chronic evolution. Third, mDCs from all patients with acute HCV infection, irrespective of their outcomes, produced higher levels of cytokines during the early acute phase in response to ssRNA than mDCs from healthy controls. However, this hyperresponsiveness was sustained only in spontaneous resolvers. Altogether, our results suggest that the immature pDC phenotype and sustained pDC and mDC hyperresponsiveness are associated with spontaneous resolution of acute HCV infection.
Molecular Evolution of the HIV-1 Thai Epidemic between the Time of RV144 Immunogen Selection to the Execution of the Vaccine Efficacy Trial
Authors: Kijak Gustavo H. , Tovanabutra Sodsai , Rerks-Ngarm Supachai , Nitayaphan Sorachai , Eamsila Chirapa , Kunasol Prayura , Khamboonruang Chirasak , Thongcharoen Prasert , Namwat Chawetsan , Premsri Nakorn , Benenson Michael , Morgan Patricia , Bose Meera , Sanders-Buell Eric , Paris Robert , Robb Merlin L. , Birx Deborah L. , De Souza Mark S. , McCutchan Francine E. , Michael Nelson L. , Kim Jerome H. 
Published: April 2013

ABSTRACTThe RV144 HIV-1 vaccine trial (Thailand, 2003 to 2009), using immunogens genetically matched to the regional epidemic, demonstrated the first evidence of efficacy for an HIV-1 vaccine. Here we studied the molecular evolution of the HIV-1 epidemic from the time of immunogen selection to the execution of the efficacy trial. We studied HIV-1 genetic diversity among 390 volunteers who were deferred from enrollment in RV144 due to preexisting HIV-1 infection using a multiregion hybridization assay, full-genome sequencing, and phylogenetic analyses. The subtype distribution was 91.7% CRF01_AE, 3.5% subtype B, 4.3% B/CRF01_AE recombinants, and 0.5% dual infections. CRF01_AE strains were 31% more diverse than the ones from the 1990s Thai epidemic. Sixty-nine percent of subtype B strains clustered with the cosmopolitan Western B strains. Ninety-three percent of B/CRF01_AE recombinants were unique; recombination breakpoint analysis showed that these strains were highly embedded within the larger network that integrates recombinants from East/Southeast Asia. Compared to Thai sequences from the early 1990s, the distance to the RV144 immunogens increased 52% to 68% for CRF01_AE Env immunogens and 12% to 29% for subtype B immunogens. Forty-three percent to 48% of CRF01_AE sequences differed from the sequence of the vaccine insert in Env variable region 2 positions 169 and 181, which were implicated in vaccine sieve effects in RV144. In conclusion, compared to the molecular picture at the early stages of vaccine development, our results show an overall increase in the genetic complexity of viruses in the Thai epidemic and in the distance to vaccine immunogens, which should be considered at the time of the analysis of the trial results.
CD27-CD70 Costimulation Controls T Cell Immunity during Acute and Persistent Cytomegalovirus Infection
Authors: Welten Suzanne P. M. , Redeker Anke , Franken Kees L. , Benedict Chris A. , Yagita Hideo , Wensveen Felix M. , Borst Jannie , Melief Cornelis J. M. , van Lier René A. W. , van Gisbergen Klaas P. J. M. , Arens Ramon 
Published: April 2013

ABSTRACTCytomegaloviruses (CMVs) establish lifelong infections that are controlled in part by CD4+and CD8+T cells. To promote persistence, CMVs utilize multiple strategies to evade host immunity, including modulation of costimulatory molecules on infected antigen-presenting cells. In humans, CMV-specific memory T cells are characterized by the loss of CD27 expression, which suggests a critical role of the costimulatory receptor-ligand pair CD27-CD70 for the development of CMV-specific T cell immunity. In this study, thein vivorole of CD27-CD70 costimulation during mouse CMV infection was examined. During the acute phase of infection, the magnitudes of CMV-specific CD4+and CD8+T cell responses were decreased in mice with abrogated CD27-CD70 costimulation. Moreover, the accumulation of inflationary memory T cells during the persistent phase of infection and the ability to undergo secondary expansion required CD27-CD70 interactions. The downmodulation of CD27 expression, however, which occurs gradually and exclusively on inflationary memory T cells, is ligand independent. Furthermore, the IL-2 production in both noninflationary and inflationary CMV-specific T cells was dependent on CD27-CD70 costimulation. Collectively, these results highlight the importance of the CD27-CD70 costimulation pathway for the development of CMV-specific T cell immunity during acute and persistent infection.
APOBEC3G Impairs the Multimerization of the HIV-1 Vif Protein in Living Cells
Authors: Batisse Julien , Guerrero Santiago Xavier , Bernacchi Serena , Richert Ludovic , Godet Julien , Goldschmidt Valérie , Mély Yves , Marquet Roland , de Rocquigny Hugues , Paillart Jean-Christophe 
Published: April 2013

ABSTRACT

The HIV-1 viral infectivity factor (Vif) is a small basic protein essential for viral fitness and pathogenicity. Vif allows productive infection in nonpermissive cells, including most natural HIV-1 target cells, by counteracting the cellular cytosine deaminases APOBEC3G (
apo
lipoprotein
B
mRNA-editing
e
nzyme
c
atalytic polypeptide-like
3G
[A3G]) and A3F. Vif is also associated with the viral assembly complex and packaged into viral particles through interactions with the viral genomic RNA and the nucleocapsid domain of Pr55
Gag
. Recently, we showed that oligomerization of Vif into high-molecular-mass complexes induces Vif folding and influences its binding to high-affinity RNA binding sites present in the HIV genomic RNA. To get further insight into the role of Vif multimerization in viral assembly and A3G repression, we used fluorescence lifetime imaging microscopy (FLIM)- and fluorescence resonance energy transfer (FRET)-based assays to investigate Vif-Vif interactions in living cells. By using two N-terminally tagged Vif proteins, we show that Vif-Vif interactions occur in living cells. This oligomerization is strongly reduced when the putative Vif multimerization domain (
161
PPLP
164
) is mutated, indicating that this domain is crucial, but that regions outside this motif also participate in Vif oligomerization. When coexpressed together with Pr55
Gag
, Vif is largely relocated to the cell membrane, where Vif oligomerization also occurs. Interestingly, wild-type A3G strongly interferes with Vif multimerization, contrary to an A3G mutant that does not bind to Vif. These findings confirm that Vif oligomerization occurs in living cells partly through its C-terminal motif and suggest that A3G may target and perturb the Vif oligomerization state to limit its functions in the cell.
Reporting trends of right-sided hyperplastic and sessile serrated polyps in a large teaching hospital over a 4-year period (2009–2012)
Authors: Gill Pelvender , Wang Lai Mun , Bailey Adam , East James E , Leedham Simon , Chetty Runjan 
Published: April 2013

AimAn audit of serrated polyps diagnosed over a 4-year period: 2009 to 2012 was undertaken to ascertain the reporting trends of sessile serrated polyps (SSP).MethodsAll right sided hyperplastic polyps (HP) proximal to the splenic flexure and all polyps designated SSP were retrieved from the study period. Three pathologists blinded to the original diagnosis re-examined the slides. Recent American College of Gastroenterology guidelines for the diagnosis of SSP was utilised.ResultsNo cases of SSP were diagnosed in 2009. In 2010, 32 right-sided cases were encountered, 83 confirmed in 2011 and 134 confirmed in 2012. The vast majority of these were right-sided.With regards to right-sided HP that were re-classified as SSP the data is as follows: 20 of 66 in 2009 (30%); 58 of 91 in 2010 (64%); 42 of 106 (40%) in 2011 and 69 of 206 in 2012 (33%).ConclusionsThis study has demonstrated an almost exponential increase in the diagnosis of SSP over a 4-year period. In addition, 30 to 64% of right-sided HP were re-classified as SSP over the 4-year period suggesting that greater awareness of the diagnostic criteria for SSP is required.SSP is an important precursor lesion in the serrated pathway of colorectal cancer. Its recognition is important for surveillance and therapeutic strategies.
Structure-Specific Endonucleases Xpf and Mus81 Play Overlapping but Essential Roles in DNA Repair by Homologous Recombination
Authors: Kikuchi Koji , Narita Takeo , Pham Van T. , Iijima Junko , Hirota Kouji , Keka Islam Shamima , Mohiuddin  , Okawa Katsuya , Hori Tetsuya , Fukagawa Tatsuo , Essers Jeroen , Kanaar Roland , Whitby Matthew C. , Sugasawa Kaoru , Taniguchi Yoshihito , Kitagawa Katsumi , Takeda Shunichi 
Published: April 2013

Abstract
DNA double-strand breaks (DSB) occur frequently during replication in sister chromatids and are dramatically increased when cells are exposed to chemotherapeutic agents including camptothecin. Such DSBs are efficiently repaired specifically by homologous recombination (HR) with the intact sister chromatid. HR, therefore, plays pivotal roles in cellular proliferation and cellular tolerance to camptothecin. Mammalian cells carry several structure-specific endonucleases, such as Xpf-Ercc1 and Mus81-Eme1, in which Xpf and Mus81 are the essential subunits for enzymatic activity. Here, we show the functional overlap between Xpf and Mus81 by conditionally inactivating Xpf in the chicken DT40 cell line, which has no Mus81 ortholog. Although mammalian cells deficient in either Xpf or Mus81 are viable, Xpf inactivation in DT40 cells was lethal, resulting in a marked increase in the number of spontaneous chromosome breaks. Similarly, inactivation of both Xpf and Mus81 in human HeLa cells and murine embryonic stem cells caused numerous spontaneous chromosome breaks. Furthermore, the phenotype of Xpf-deficient DT40 cells was reversed by ectopic expression of human Mus81-Eme1 or human Xpf-Ercc1 heterodimers. These observations indicate the functional overlap of Xpf-Ercc1 and Mus81-Eme1 in the maintenance of genomic DNA. Both Mus81-Eme1 and Xpf-Ercc1 contribute to the completion of HR, as evidenced by the data that the expression of Mus81-Eme1 or Xpf-Ercc1 diminished the number of camptothecin-induced chromosome breaks in Xpf-deficient DT40 cells, and to preventing early steps in HR by deleting XRCC3 suppressed the nonviability of Xpf-deficient DT40 cells. In summary, Xpf and Mus81 have a substantially overlapping function in completion of HR. Cancer Res; 73(14); 4362–71. ©2013 AACR.
FGFR1 Is Essential for Prostate Cancer Progression and Metastasis
Authors: Yang Feng , Zhang Yongyou , Ressler Steven J. , Ittmann Michael M. , Ayala Gustavo E. , Dang Truong D. , Wang Fen , Rowley David R. 
Published: April 2013

Abstract
The fibroblast growth factor receptor 1 (FGFR1) is ectopically expressed in prostate carcinoma cells, but its functional contributions are undefined. In this study, we report the evaluation of a tissue-specific conditional deletion mutant generated in an ARR2PBi(Pbsn)-Cre/TRAMP/fgfr1loxP/loxP transgenic mouse model of prostate cancer. Mice lacking fgfr1, in prostate cells developed smaller tumors that also included distinct cancer foci still expressing fgfr1 indicating focal escape from gene excision. Tumors with confirmed fgfr1 deletion exhibited increased foci of early, well-differentiated cancer and phyllodes-type tumors, and tumors that escaped fgfr1 deletion primarily exhibited a poorly differentiated phenotype. Consistent with these phenotypes, mice carrying the fgfr1 null allele survived significantly longer than those without fgfr1 deletion. Most interestingly, all metastases were primarily negative for the fgfr1 null allele, exhibited high FGFR1 expression, and a neuroendocrine phenotype regardless of fgfr1 status in the primary tumors. Together, these results suggest a critical and permissive role of ectopic FGFR1 signaling in prostate tumorigenesis and particularly in mechanisms of metastasis. Cancer Res; 73(12); 3716–24. ©2013 AACR.
PFI-1, a Highly Selective Protein Interaction Inhibitor, Targeting BET Bromodomains
Authors: Picaud Sarah , Da Costa David , Thanasopoulou Angeliki , Filippakopoulos Panagis , Fish Paul V. , Philpott Martin , Fedorov Oleg , Brennan Paul , Bunnage Mark E. , Owen Dafydd R. , Bradner James E. , Taniere Philippe , O'Sullivan Brendan , Müller Susanne , Schwaller Juerg , Stankovic Tatjana , Knapp Stefan 
Published: April 2013

Abstract
Bromo and extra terminal (BET) proteins (BRD2, BRD3, BRD4, and BRDT) are transcriptional regulators required for efficient expression of several growth promoting and antiapoptotic genes as well as for cell-cycle progression. BET proteins are recruited on transcriptionally active chromatin via their two N-terminal bromodomains (BRD), a protein interaction module that specifically recognizes acetylated lysine residues in histones H3 and H4. Inhibition of the BET–histone interaction results in transcriptional downregulation of a number of oncogenes, providing a novel pharmacologic strategy for the treatment of cancer. Here, we present a potent and highly selective dihydroquinazoline-2-one inhibitor, PFI-1, which efficiently blocks the interaction of BET BRDs with acetylated histone tails. Cocrystal structures showed that PFI-1 acts as an acetyl-lysine (Kac) mimetic inhibitor efficiently occupying the Kac binding site in BRD4 and BRD2. PFI-1 has antiproliferative effects on leukemic cell lines and efficiently abrogates their clonogenic growth. Exposure of sensitive cell lines with PFI-1 results in G1 cell-cycle arrest, downregulation of MYC expression, as well as induction of apoptosis and induces differentiation of primary leukemic blasts. Intriguingly, cells exposed to PFI-1 showed significant downregulation of Aurora B kinase, thus attenuating phosphorylation of the Aurora substrate H3S10, providing an alternative strategy for the specific inhibition of this well-established oncology target. Cancer Res; 73(11); 3336–46. ©2013 AACR.