bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendritic Cell Immunoreceptor Regulates Chikungunya Virus Pathogenesis in Mice
Authors: Long Kristin M. , Whitmore Alan C. , Ferris Martin T. , Sempowski Gregory D. , McGee Charles , Trollinger Bianca , Gunn Bronwyn , Heise Mark T. 
Published: March 2013

ABSTRACTChikungunya virus (CHIKV) is a mosquito-borne alphavirus responsible for recent epidemic outbreaks of debilitating disease in humans. Alphaviruses are known to interact with members of the C-type lectin receptor family of pattern recognition proteins, and given that the dendritic cell immunoreceptor (DCIR) is known to act as a negative regulator of the host inflammatory response and has previously been associated with rheumatoid arthritis, we evaluated DCIR's role in response to CHIKV infection. Although we observed an increase in the proportion of dendritic cells at the site of CHIKV infection at 24 to 36 h postinfection, these cells showed decreased cell surface DCIR, suggestive of DCIR triggering and internalization.In vitro, bone marrow-derived dendritic cells from DCIR-deficient (DCIR−/−) mice exhibited altered cytokine expression following exposure to CHIKV. DCIR−/−mice exhibited more severe disease signs than wild-type C57BL6/J mice following CHIKV infection, including a more rapid and more severe onset of virus-induced edema and enhanced weight loss. Histological examination revealed that DCIR-deficient animals exhibited increased inflammation and damage in both the fascia of the inoculated foot and the ankle joint, and DCIR deficiency skewed the CHIKV-induced cytokine response at the site of infection at multiple times postinfection. Early differences in virus-induced disease between C57BL6/J and DCIR−/−mice were independent of viral replication, while extended viral replication correlated with enhanced foot swelling and tissue inflammation and damage in DCIR−/−compared to C57BL6/J mice at 6 to 7 days postinfection. These results suggest that DCIR plays a protective role in limiting the CHIKV-induced inflammatory response and subsequent tissue and joint damage.
A Proautophagic Antiviral Role for the Cellular Prion Protein Identified by Infection with a Herpes Simplex Virus 1 ICP34.5 Mutant
Authors: Korom Maria , Wylie Kristine M. , Wang Hong , Davis Katie L. , Sangabathula Meher S. , DeLassus Gregory S. , Morrison Lynda A. 
Published: March 2013

ABSTRACT

The cellular prion protein (PrP) often plays a cytoprotective role by regulating autophagy in response to cell stress. The stress of infection with intracellular pathogens can stimulate autophagy, and autophagic degradation of pathogens can reduce their replication and thus help protect the infected cells. PrP also restricts replication of several viruses, but whether this activity is related to an effect on autophagy is not known. Herpes simplex virus 1 (HSV-1) effectively counteracts autophagy through binding of its ICP34.5 protein to the cellular proautophagy protein beclin-1. Autophagy can reduce replication of an HSV-1 mutant, Δ68H, which is incapable of binding beclin-1. We found that deletion of PrP in mice complements the attenuation of Δ68H, restoring its capacity to replicate in the central nervous system (CNS) to wild-type virus levels after intracranial or corneal infection. Cultured primary astrocytes but not neurons derived from PrP
−/−
mice also complemented the attenuation of Δ68H, enabling Δ68H to replicate at levels equivalent to wild-type virus. Ultrastructural analysis showed that normal astrocytes exhibited an increase in the number of autophagosomes after infection with Δ68H compared with wild-type virus, but PrP
−/−
astrocytes failed to induce autophagy in response to Δ68H infection. Redistribution of EGFP-LC3 into punctae occurred more frequently in normal astrocytes infected with Δ68H than with wild-type virus, but not in PrP
−/−
astrocytes, corroborating the ultrastructural analysis results. Our results demonstrate that PrP is critical for inducing autophagy in astrocytes in response to HSV-1 infection and suggest that PrP positively regulates autophagy in the mouse CNS.
Crystal Structure of Enterovirus 71 RNA-Dependent RNA Polymerase Complexed with Its Protein Primer VPg: Implication for a
trans
Mechanism of VPg Uridylylation
Authors: Chen Cheng , Wang Yaxin , Shan Chao , Sun Yuna , Xu Peng , Zhou Honggang , Yang Cheng , Shi Pei-Yong , Rao Zihe , Zhang Bo , Lou Zhiyong 
Published: March 2013

ABSTRACT

Picornavirus RNA replication is initiated by VPg uridylylation, during which the hydroxyl group of the third tyrosine residue of the virally encoded protein VPg is covalently linked to two UMP molecules by RNA-dependent RNA polymerase (RdRp; also known as 3D
pol
). We previously identified site 311, located at the base of the palm domain of the enterovirus 71 (EV71) RdRp, to be the site for EV71 VPg binding and uridylylation. Here we report the crystal structure of EV71 3D
pol
complexed with VPg. VPg was anchored at the bottom of the palm domain of the 3D
pol
molecule and exhibited an extended V-shape conformation. The corresponding interface on 3D
pol
was mainly formed by residues within site 311 and other residues in the palm and finger domains. Mutations of the amino acids of 3D
pol
involved in the VPg interaction (
3D
L319A,
3D
D320A, and
3D
Y335A) significantly disrupted VPg binding to 3D
pol
, resulting in defective VPg uridylylation. In contrast, these mutations did not affect the RNA elongation activity of 3D
pol
. In the context of viral genomic RNA, mutations that abolished VPg uridylylation activity were lethal for EV71 replication. Further
in vitro
analysis showed that the uridylylation activity was restored by mixing VPg-binding-defective and catalysis-defective mutants, indicating a
trans
mechanism for EV71 VPg uridylylation. Our results, together with previous results of other studies, demonstrate that different picornaviruses use distinct binding sites for VPg uridylylation.
tatExon 1 Exhibits Functional Diversity during HIV-1 Subtype C Primary Infection
Authors: Rossenkhan Raabya , MacLeod Iain J. , Sebunya Theresa K. , Castro-Nallar Eduardo , McLane Mary Fran , Musonda Rosemary , Gashe Berhanu A. , Novitsky Vlad , Essex M. 
Published: March 2013

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) Tat is a mediator of viral transcription and is involved in the control of virus replication. However, associations between HIV-1 Tat diversity and functional effects during primary HIV-1 infection are still unclear. We estimated selection pressures intatexon 1 using the mixed-effects model of evolution with 672 viral sequences generated from 20 patients infected with HIV-1 subtype C (HIV-1C) over 500 days postseroconversion.tatexon 1 residues 3, 4, 21, 24, 29, 39, and 68 were under positive selection, and we established that specific amino acid signature patterns were apparent in primary HIV-1C infection compared with chronic infection. We assessed the impact of these mutations on long terminal repeat (LTR) activity and found that Tat activity was negatively affected by the Ala21substitution identified in 13/20 (65%) of patients, which reduced LTR activity by 88% (±1%) (P< 0.001). The greatest increase in Tat activity was seen with the Gln35/Lys39double mutant that resulted in an additional 49% (±14%) production of LTR-driven luciferase (P= 0.012). There was a moderate positive correlation between Tat-mediated LTR activity and HIV-1 RNA in plasma (P= 0.026;r= 0.400) after 180 days postseroconversion that was reduced by 500 days postseroconversion (P= 0.043;r= 0.266). Although Tat activation of the LTR is not a strong predictor of these clinical variables, there are significant linear relationships between Tat transactivation and patients' plasma viral loads and CD4 counts, highlighting the complex interplay between Tat mutations in early HIV-1C infection.
Modulation of Mitogen-Activated Protein Kinase-Activated Protein Kinase 3 by Hepatitis C Virus Core Protein
Authors: Ngo Huong T. T. , Pham Long V. , Kim Jong-Wook , Lim Yun-Sook , Hwang Soon B. 
Published: March 2013

ABSTRACT

Hepatitis C virus (HCV) is highly dependent on cellular proteins for its own propagation. In order to identify the cellular factors involved in HCV propagation, we performed protein microarray assays using the HCV core protein as a probe. Of ∼9,000 host proteins immobilized in a microarray, approximately 100 cellular proteins were identified as HCV core-interacting partners. Of these candidates, mitogen-activated protein kinase-activated protein kinase 3 (MAPKAPK3) was selected for further characterization. MAPKAPK3 is a serine/threonine protein kinase that is activated by stress and growth inducers. Binding of HCV core to MAPKAPK3 was confirmed by
in vitro
pulldown assay and further verified by coimmunoprecipitation assay. HCV core protein interacted with MAPKAPK3 through amino acid residues 41 to 75 of core and the N-terminal half of kinase domain of MAPKAPK3. In addition, both RNA and protein levels of MAPKAPK3 were elevated in both HCV subgenomic replicon cells and cell culture-derived HCV (HCVcc)-infected cells. Silencing of MAPKAPK3 expression resulted in decreases in both protein and HCV infectivity levels but not in the intracellular HCV RNA level. We showed that MAPKAPK3 increased HCV IRES-mediated translation and MAPKAPK3-dependent HCV IRES activity was further increased by core protein. These data suggest that HCV core may modulate MAPKAPK3 to facilitate its own propagation.
Dissociation between Transmissible Spongiform Encephalopathy (TSE) Infectivity and Proteinase K-Resistant PrP
Sc
Levels in Peripheral Tissue from a Murine Transgenic Model of TSE Disease
Authors: Dobie Karen , Barron Rona 
Published: March 2013

ABSTRACT

Most current diagnostic tests for transmissible spongiform encephalopathies (TSE) rely on the presence of proteinase K (PK)-resistant PrP
Sc
(PrP-res) in postmortem tissues as an indication of TSE disease. However, a number of studies have highlighted a discrepancy between TSE infectivity and PrP-res levels in both natural and experimental cases of TSE disease. Previously, we have shown high TSE infectivity levels in the brain tissue of mice that have a clinical TSE disease with associated vacuolar pathology but little or no detectable PrP-res. Here, the levels of TSE infectivity and PrP-res within a peripheral tissue of this mouse model were investigated. Biochemical analysis showed that low levels of PrP-res were present in the spleen tissue in comparison to the levels observed in the spleen of mice infected with ME7 or 79A. However, upon subpassage of brain and spleen tissue from clinically ill mice with little or no PrP-res detectable, similar short incubation periods to disease were observed, indicating that infectivity levels were similarly high in both tissues. Thus, the discrepancy between PrP-res and TSE infectivity was also present in the peripheral tissues of this disease model. This result indicates that peripheral tissues can contain higher levels of infectivity given the correct combination of host species, PrP genotype, and TSE agent. Therefore, the assumption that the levels of peripheral infectivity are lower than those in the central nervous system is not always correct, and this could have implications for current food safety regulations.
The Herpes Simplex Virus 2 UL21 Protein Is Essential for Virus Propagation
Authors: Le Sage Valerie , Jung Masany , Alter Jake D. , Wills Elizabeth G. , Johnston Susan M. , Kawaguchi Yasushi , Baines Joel D. , Banfield Bruce W. 
Published: March 2013

ABSTRACT

Herpes simplex virus 2 (HSV-2) is an important human pathogen that is the major cause of genital herpes infections and a significant contributor to the epidemic spread of human immunodeficiency virus infections. The
UL21
gene is conserved throughout the
Alphaherpesvirinae
subfamily and encodes a tegument protein that is dispensable for HSV-1 and pseudorabies virus replication in cultured cells; however, its precise functions have not been determined. To investigate the role of UL21 in the HSV-2 replicative cycle, we constructed a
UL21
deletion virus (HSV-2 ΔUL21) using an HSV-2 bacterial artificial chromosome, pYEbac373. HSV-2 ΔUL21 was unable to direct the production of infectious virus in noncomplementing cells, whereas the repaired HSV-2 ΔUL21 strain grew to wild-type (WT) titers, indicating that UL21 is essential for virus propagation. Cells infected with HSV-2 ΔUL21 demonstrated a 2-h delay in the kinetics of immediate early viral gene expression. However, this delay in gene expression was not responsible for the inability of cells infected with HSV-2 ΔUL21 to produce virus insofar as late viral gene products accumulated to WT levels by 24 h postinfection (hpi). Electron and fluorescence microscopy studies indicated that DNA-containing capsids formed in the nuclei of ΔUL21-infected cells, while significantly reduced numbers of capsids were located in the cytoplasm late in infection. Taken together, these data indicate that HSV-2 UL21 has an early function that facilitates viral gene expression as well as a late essential function that promotes the egress of capsids from the nucleus.
Seeing you through London 2012: eye care at the Olympics
Authors: D'Ath Penny J , Thomson W David , Wilson Clare M 
Published: March 2013

BackgroundProvision of eye care services for competitors and their support teams has become an integral part of the modern Olympic Games.AimTo describe the organisation of the eye clinic at London 2012 over a 4-week period and provide outline audit data.MethodsThe clinic employed multidisciplinary eye care professionals and utilised state-of-the-art instrumentation to provide the highest level of eye care.ResultsA total of 1406 patients from 154 countries attended the clinic over the Olympic Games, of which, 276 were competitors. All individuals received a comprehensive refractive and ocular health examination. Minor ocular injuries, glaucoma, diabetic retinopathy and macular degeneration were among the conditions detected and managed. Most patients attended the clinic to have their refractive status checked: 973 spectacles and 50 pairs of contact lenses were dispensed.ConclusionsIt is hoped that this account of the provision of eye care at London 2012 will assist with the planning of this service at future events.
Characterisation of the pharmacokinetics of ethinylestradiol and drospirenone in extended-cycle regimens: population pharmacokinetic analysis from a randomised Phase III study
Authors: Reif Stefanie , Snelder Nelleke , Blode Hartmut 
Published: March 2013

ObjectivesThe primary objective of this analysis was to characterise the steady-state pharmacokinetics (PK) of ethinylestradiol (EE) and drospirenone (DRSP) in a randomised Phase III study that investigated the contraceptive efficacy and safety of three different regimens of EE 20 µg/DRSP 3 mg.MethodsNon-linear mixed-effects modelling was used to develop population PK models for EE and DRSP. EE and DRSP serum concentrations were determined in blood samples obtained from approximately 1100 healthy young women on two occasions during the first cycle (Week 3) and after 6 months (Week 27) of EE 20 µg/DRSP 3 mg use. EE 20 µg/DRSP 3 mg was administered as a flexible extended regimen [24–120 days’ active hormonal intake followed by 4 days with no tablet intake (tablet-free interval)], a conventional 28-day cyclic regimen (24 days’ active hormonal intake followed by 4 days of placebo tablets) or a fixed extended regimen (120 days’ uninterrupted active hormonal intake followed by a 4-day tablet-free interval) over 1 year.ResultsThe population PK of EE and DRSP in this population were successfully described using the developed population models. All three regimens led to similar steady-state drug exposure during long-term treatment. Only minor changes (≤8%) in the steady-state PK of EE and DRSP were observed between Week 3 and Week 27 of an extended regimen. Body weight (BW) and age had a small, statistically significant impact on the PK of EE and DRSP (BW only) in a covariate analysis, however, these changes were not considered to be clinically relevant.ConclusionsExtending the established 24/4-day regimen of EE 20 µg/DRSP 3 mg does not change the known steady-state PK of EE and DRSP, suggesting that the clinical efficacy is also similar. This is in line with the published clinical results from this study.
Combined hormonal contraceptives and the risk of venous and arterial thromboembolism and cardiovascular death: misuse of automated databases
Authors: Shapiro Samuel 
Published: March 2013

BackgroundIn December 2011, the US Food and Drug Administration (FDA) convened a public Advisory Committee meeting to review evidence from a study commissioned by the agency. An analysis of findings derived from four databases was published on the FDA website, and presented at the meeting. Among users of combined hormonal contraceptives containing ethinylestradiol (EE) plus drospirenone (DRSP) the risks of venous (VTE) and arterial thromboembolism (ATE) were higher than among users of older reference contraceptives containing other progestogens. The findings have now been published in a peer-reviewed journal.ObjectiveTo evaluate the published evidence.MethodsGenerally accepted epidemiological principles of causality are applied.ResultsThe findings did not satisfy the criteria of time order, bias, confounding, statistical stability and strength of association, duration-response, internal consistency, external consistency, or biological plausibility.ConclusionsThe best evidence continues to suggest that the increased risk of VTE in combined hormonal contraceptive users is dependent on the dose of estrogen, and independent of the progestogen used. The best evidence also suggests that DRSP does not increase the risk of ATE, and may reduce it.
High prevalence and incidence of human papillomavirus in a cohort of healthy young African female subjects
Authors: Watson-Jones Deborah , Baisley Kathy , Brown Joelle , Kavishe Bazil , Andreasen Aura , Changalucha John , Mayaud Philippe , Kapiga Saidi , Gumodoka Balthazar , Hayes Richard J , de Sanjosé Silvia 
Published: March 2013

ObjectivesWe measured the prevalence and incidence of human papillomavirus (HPV) infection in young female subjects recruited for a safety and immunogenicity trial of the bivalent HPV-16/18 vaccine in Tanzania.MethodsHealthy HIV negative female subjects aged 10–25 years were enrolled and randomised (2:1) to receive HPV-16/18 vaccine or placebo (Al(OH)3control). At enrolment, if sexually active, genital specimens were collected for HPV DNA, other reproductive tract infections and cervical cytology. Subjects were followed to 12 months when HPV testing was repeated.ResultsIn total 334 participants were enrolled; 221 and 113 in vaccine and control arms, respectively. At enrolment, 74% of 142 sexually active subjects had HPV infection of whom 69% had >1 genotype. Prevalent infections were HPV-45 (16%), HPV-53 (14%), HPV-16 (13%) and HPV-58 (13%). Only age was associated with prevalent HPV infection at enrolment. Among 23 girls who reported age at first sex as 1 year younger than their current age, 15 (65.2%) had HPV infection. Of 187 genotype-specific infections at enrolment, 51 (27%) were present at 12 months. Overall, 67% of 97 sexually active participants with results at enrolment and 12 months had a new HPV genotype at follow-up. Among HPV uninfected female subjects at enrolment, the incidence of any HPV infection was 76 per 100 person-years.ConclusionsAmong young women in Tanzania, HPV is highly prevalent and acquired soon after sexual debut. Early HPV vaccination is highly recommended in this population.
Transient heparin-induced platelet activation linked to generation of platelet 12-lipoxygenase
Authors: McMahon Greg S. , Jones Chris I. , Hayes Paul D. , Naylor A. Ross , Goodall Alison H. 
Published: March 2013

SummaryPreviously we demonstrated that heparin administration during carotid endarterectomy (CEA) caused a marked, but transient increase in platelet aggregation to arachidonic acid (AA) and adenosine diphosphate (ADP), despite effective platelet cyclo-oxygenase-1 (COX-1) inhibition with aspirin. Here we investigated the metabolism of AA via platelet 12-lipoxygenase (12-LOX) as a possible mediator of the observed transient aspirin resistance, and compared the effects of unfractionated (UFH) and low-molecular-weight (LMWH) heparin. A total of 43 aspirinated patients undergoing CEA were randomised in the trial to 5,000 IU UFH (n=22) or 2,500 IU LMWH (dalteparin, n=21). Platelet aggregation to AA (4×10–3) and ADP (3×10–6) was determined, and the products of the COX-1 and 12-LOX pathways; thromboxane B2 (TXB2) and 12-hydroxyeicosatretraenoic acid (12-HETE) were measured in plasma, and in material released from aggregating platelets. Aggregation to AA increased significantly (∼10-fold) following heparinisation (p<0.0001), irrespective of heparin type (p=0.33). Significant, but smaller (∼2-fold) increases in aggregation to ADP were also seen, which were significantly lower in the platelets of patients randomised to LMWH (p<0.0001). Plasma levels of TxB2 did not rise following heparinisation (p=0.93), but 12-HETE increased significantly in the patients’ plasma, and released from platelets stimulated in vitro with ADP, with both heparin types (p<0.0001). The magnitude of aggregation to ADP correlated with 12-HETE generation (p=0.03). Heparin administration during CEA generates AA that is metabolised to 12-HETE via the 12-LOX pathway, possibly explaining the phenomenon of transient heparin-induced platelet activation. LMWH has less effect on aggregation and 12-HETE generation than UFH when the platelets are stimulated with ADP.
Structure of plasma and tissue kallikreins
Authors: Pathak Monika , Shen Wong Szu , Dreveny Ingrid , Emsley Jonas 
Published: March 2013

SummaryThe kallikrein kinin system (KKS) consists of serine proteases involved in the production of peptides called kinins, principally bradykinin and Lys-bradykinin (kallidin). The KKS contributes to a variety of physiological processes including inflammation, blood pressure control and coagulation. Here we review the protein structural data available for these serine proteases and examine the molecular mechanisms of zymogen activation and substrate recognition focusing on plasma kallikrein (PK) and tissue kallikrein (KLK1) cleavage of kininogens. PK circulates as a zymogen bound to high-molecular-weight kininogen (HK). PK is activated by coagulation factor XIIa and then cleaves HK to generate bradykinin and factor XII to generate further XIIa. A structure has been described for the activated PK protease domain in complex with the inhibitor benzamidine. Kallikrein-related peptidases (KLKs) have a distinct domain structure and exist as a family of 15 genes which are differentially expressed in many tissues and the central nervous system. They cleave a wide variety of substrates including low-molecular-weight kininogen (LK) and matrix proteins. Crystal structures are available for KLK1, 3, 4, 5, 6 and 7 activated protease domains typically in complex with S1 pocket inhibitors. A substrate mimetic complex is described for KLK3 which provides insight into substrate recognition. A zymogen crystal structure determined for KLK6 reveals a closed S1 pocket and a novel mechanism of zymogen activation. Overall these structures have proved highly informative in understanding the molecular mechanisms of the KKS and provide templates to design inhibitors for treatment of a variety of diseases.