bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of COX-2/PGE
2
Promotes Sapovirus Replication via the Inhibition of Nitric Oxide Production
Authors: Alfajaro Mia Madel , Choi Jong-Soon , Kim Deok-Song , Seo Ja-Young , Kim Ji-Yun , Park Jun-Gyu , Soliman Mahmoud , Baek Yeong-Bin , Cho Eun-Hyo , Kwon Joseph , Kwon Hyung-Jun , Park Su-Jin , Lee Woo Song , Kang Mun-Il , Hosmillo Myra , Goodfellow Ian , Cho Kyoung-Oh 
Published: November 2016

ABSTRACT

Enteric caliciviruses in the genera
Norovirus
and
Sapovirus
are important pathogens that cause severe acute gastroenteritis in both humans and animals. Cyclooxygenases (COXs) and their final product, prostaglandin E
2
(PGE
2
), are known to play important roles in the modulation of both the host response to infection and the replicative cycles of several viruses. However, the precise mechanism(s) by which the COX/PGE
2
pathway regulates sapovirus replication remains largely unknown. In this study, infection with porcine sapovirus (PSaV) strain Cowden, the only cultivable virus within the genus
Sapovirus
, markedly increased COX-2 mRNA and protein levels at 24 and 36 h postinfection (hpi), with only a transient increase in COX-1 levels seen at 24 hpi. The treatment of cells with pharmacological inhibitors, such as nonsteroidal anti-inflammatory drugs or small interfering RNAs (siRNAs) against COX-1 and COX-2, significantly reduced PGE
2
production, as well as PSaV replication. Expression of the viral proteins VPg and ProPol was associated with activation of the COX/PGE
2
pathway. We observed that pharmacological inhibition of COX-2 dramatically increased NO production, causing a reduction in PSaV replication that could be restored by inhibition of nitric oxide synthase via the inhibitor
N
-nitro-
l
-methyl-arginine ester. This study identified a pivotal role for the COX/PGE
2
pathway in the regulation of NO production during the sapovirus life cycle, providing new insights into the life cycle of this poorly characterized family of viruses. Our findings also reveal potential new targets for treatment of sapovirus infection.

IMPORTANCE
Sapoviruses are among the major etiological agents of acute gastroenteritis in both humans and animals, but little is known about sapovirus host factor requirements. Here, using only cultivable porcine sapovirus (PSaV) strain Cowden, we demonstrate that PSaV induced the vitalization of the cyclooxygenase (COX) and prostaglandin E
2
(PGE
2
) pathway. Targeting of COX-1/2 using nonsteroidal anti-inflammatory drugs (NSAIDs) such as the COX-1/2 inhibitor indomethacin and the COX-2-specific inhibitors NS-398 and celecoxib or siRNAs targeting COXs, inhibited PSaV replication. Expression of the viral proteins VPg and ProPol was associated with activation of the COX/PGE
2
pathway. We further demonstrate that the production of PGE
2
provides a protective effect against the antiviral effector mechanism of nitric oxide. Our findings uncover a new mechanism by which PSaV manipulates the host cell to provide an environment suitable for efficient viral growth, which in turn can be a new target for treatment of sapovirus infection.
The Crystal Structure of the Fifth Scavenger Receptor Cysteine-Rich Domain of Porcine CD163 Reveals an Important Residue Involved in Porcine Reproductive and Respiratory Syndrome Virus Infection
Authors: Ma Hongfang , Jiang Longguang , Qiao Songlin , Zhi Yubao , Chen Xin-Xin , Yang Yanyan , Huang Xiaojing , Huang Mingdong , Li Rui , Zhang Gai-Ping 
Published: November 2016

ABSTRACT

Porcine reproductive and respiratory syndrome (PRRS) has become an economically critical factor in swine industry since its worldwide spread in the 1990s. Infection by its causative agent, PRRS virus (PRRSV), was proven to be mediated by an indispensable receptor, porcine CD163 (pCD163), and the fifth scavenger receptor cysteine-rich domain (SRCR5) is essential for virus infection. However, the structural details and specific residues of pCD163 SRCR5 involved in infection have not been defined yet. In this study, we prepared recombinant pCD163 SRCR5 in
Drosophila melanogaster
Schneider 2 (S2) cells and determined its crystal structure at a high resolution of 2.0 Å. This structure includes a markedly long loop region and shows a special electrostatic potential, and these are significantly different from those of other members of the scavenger receptor cysteine-rich superfamily (SRCR-SF). Subsequently, we carried out structure-based mutational studies to identify that the arginine residue at position 561 (Arg561) in the long loop region is important for PRRSV infection. Further, we showed Arg561 probably takes effect on the binding of pCD163 to PRRSV during virus invasion. Altogether the current work provides the first view of the CD163 SRCR domain, expands our knowledge of the invasion mechanism of PRRSV, and supports a molecular basis for prevention and control of the virus.

IMPORTANCE
PRRS has caused huge economic losses to pig farming. The syndrome is caused by PRRSV, and PRRSV infection has been shown to be mediated by host cell surface receptors. One of them, pCD163, is especially indispensable, and its SRCR5 domain has been further demonstrated to play a significant role in virus infection. However, its structural details and the residues involved in infection are unknown. In this study, we determined the crystal structure of pCD163 SRCR5 and then carried out site-directed mutational studies based on the crystal structure to elucidate which residue is important. Our work not only provides structural information on the CD163 SRCR domain for the first time but also indicates the molecular mechanism of PRRSV infection and lays a foundation for future applications in prevention and control of PRRS.
Porcine Reproductive and Respiratory Syndrome Virus nsp1α Inhibits NF-κB Activation by Targeting the Linear Ubiquitin Chain Assembly Complex
Authors: Jing Huiyuan , Fang Liurong , Ding Zhen , Wang Dang , Hao Wenqi , Gao Li , Ke Wenting , Chen Huanchun , Xiao Shaobo 
Published: November 2016

ABSTRACT

Linear ubiquitination, a newly discovered posttranslational modification, is catalyzed by the linear ubiquitin chain assembly complex (LUBAC), which is composed of three subunits: one catalytic subunit HOIP and two accessory molecules, HOIL-1L and SHARPIN. Accumulating evidence suggests that linear ubiquitination plays a crucial role in innate immune signaling and especially in the activation of the NF-κB pathway by conjugating linear polyubiquitin chains to NF-κB essential modulator (NEMO, also called IKKγ), the regulatory subunit of the IKK complex. Porcine reproductive and respiratory syndrome virus (PRRSV), an
Arterivirus
that has devastated the swine industry worldwide, is an ideal model to study the host's disordered inflammatory responses after viral infection. Here, we found that LUBAC-induced NF-κB and proinflammatory cytokine expression can be inhibited in the early phase of PRRSV infection. Screening the PRRSV-encoded proteins showed that nonstructural protein 1α (nsp1α) suppresses LUBAC-mediated NF-κB activation and its CTE domain is required for the inhibition. Mechanistically, nsp1α binds to HOIP/HOIL-1L and impairs the interaction between HOIP and SHARPIN, thus reducing the LUBAC-dependent linear ubiquitination of NEMO. Moreover, PRRSV infection also blocks LUBAC complex formation and NEMO linear-ubiquitination, the important step for transducing NF-κB signaling. This unexpected finding demonstrates a previously unrecognized role of PRRSV nsp1α in modulating LUBAC signaling and explains an additional mechanism of immune modulation by PRRSV.

IMPORTANCE
Porcine reproductive and respiratory syndrome (PRRS) is one of the most important veterinary infectious diseases in countries with intensive swine industries. PRRS virus (PRRSV) infection usually suppresses proinflammatory cytokine expression in the early stage of infection, whereas it induces an inflammatory storm in the late stage. However, precisely how the virus is capable of doing so remains obscure. In this study, we found that by blocking the interaction of its catalytic subunit HOIP and accessory molecule SHARPIN, PRRSV can suppress NF-κB signal transduction in the early stage of infection. Our findings not only reveal a novel mechanism evolved by PRRSV to regulate inflammatory responses but also highlight the important role of linear ubiquitination modification during virus infection.
Modeling Severe Fever with Thrombocytopenia Syndrome Virus Infection in Golden Syrian Hamsters: Importance of STAT2 in Preventing Disease and Effective Treatment with Favipiravir
Authors: Gowen Brian B. , Westover Jonna B. , Miao Jinxin , Van Wettere Arnaud J. , Rigas Johanna D. , Hickerson Brady T. , Jung Kie-Hoon , Li Rong , Conrad Bettina L. , Nielson Skot , Furuta Yousuke , Wang Zhongde 
Published: November 2016

ABSTRACT

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease endemic in parts of Asia. The etiologic agent, SFTS virus (SFTSV; family
Bunyaviridae
, genus
Phlebovirus
) has caused significant morbidity and mortality in China, South Korea, and Japan, with key features of disease being intense fever, thrombocytopenia, and leukopenia. Case fatality rates are estimated to be in the 30% range, and no antivirals or vaccines are approved for use for treatment and prevention of SFTS. There is evidence that in human cells, SFTSV sequesters STAT proteins in replication complexes, thereby inhibiting type I interferon signaling. Here, we demonstrate that hamsters devoid of functional STAT2 are highly susceptible to as few as 10 PFU of SFTSV, with animals generally succumbing within 5 to 6 days after subcutaneous challenge. The disease included marked thrombocytopenia and inflammatory disease characteristic of the condition in humans. Infectious virus titers were present in the blood and most tissues 3 days after virus challenge, and severe inflammatory lesions were found in the spleen and liver samples of SFTSV-infected hamsters. We also show that SFTSV infection in
STAT2
knockout (KO) hamsters is responsive to favipiravir treatment, which protected all animals from lethal disease and reduced serum and tissue viral loads by 3 to 6 orders of magnitude. Taken together, our results provide additional insights into the pathogenesis of SFTSV infection and support the use of the newly described
STAT2
KO hamster model for evaluation of promising antiviral therapies.

IMPORTANCE
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral disease for which there are currently no therapeutic options or available vaccines. The causative agent, SFTS virus (SFTSV), is present in China, South Korea, and Japan, and infections requiring medical attention result in death in as many as 30% of the cases. Here, we describe a novel model of SFTS in hamsters genetically engineered to be deficient in a protein that helps protect humans and animals against viral infections. These hamsters were found to be susceptible to SFTSV and share disease features associated with the disease in humans. Importantly, we also show that SFTSV infection in hamsters can be effectively treated with a broad-spectrum antiviral drug approved for use in Japan. Our findings suggest that the new SFTS model will be an excellent resource to better understand SFTSV infection and disease as well as a valuable tool for evaluating promising antiviral drugs.
The Many Faces of the Flavivirus NS5 Protein in Antagonism of Type I Interferon Signaling
Authors: Best Sonja M. 
Published: November 2016

ABSTRACT
The vector-borne flaviviruses cause severe disease in humans on every inhabited continent on earth. Their transmission by arthropods, particularly mosquitoes, facilitates large emergence events such as witnessed with Zika virus (ZIKV) or West Nile virus in the Americas. Every vector-borne flavivirus examined thus far that causes disease in humans, from dengue virus to ZIKV, antagonizes the host type I interferon (IFN-I) response by preventing JAK-STAT signaling, suggesting that suppression of this pathway is an important determinant of infection. The most direct and potent viral inhibitor of this pathway is the nonstructural protein NS5. However, the mechanisms utilized by NS5 from different flaviviruses are often quite different, sometimes despite close evolutionary relationships between viruses. The varied mechanisms of NS5 as an IFN-I antagonist are also surprising given that the evolution of NS5 is restrained by the requirement to maintain function of two enzymatic activities critical for virus replication, the methyltransferase and RNA-dependent RNA polymerase. This review discusses the different strategies used by flavivirus NS5 to evade the antiviral effects of IFN-I and how this information can be used to better model disease and develop antiviral countermeasures.
Identification of New World Quails Susceptible to Infection with Avian Leukosis Virus Subgroup J
Authors: Plachý Jiří , Reinišová Markéta , Kučerová Dana , Šenigl Filip , Stepanets Volodymyr , Hron Tomáš , Trejbalová Kateřina , Elleder Daniel , Hejnar Jiří 
Published: November 2016

ABSTRACT

The J subgroup of avian leukosis virus (ALV-J) infects domestic chickens, jungle fowl, and turkeys. This virus enters the host cell through a receptor encoded by the
tvj
locus and identified as Na
+
/H
+
exchanger 1. The resistance to avian leukosis virus subgroup J in a great majority of galliform species has been explained by deletions or substitutions of the critical tryptophan 38 in the first extracellular loop of Na
+
/H
+
exchanger 1. Because there are concerns of transspecies virus transmission, we studied natural polymorphisms and susceptibility/resistance in wild galliforms and found the presence of tryptophan 38 in four species of New World quails. The embryo fibroblasts of New World quails are susceptible to infection with avian leukosis virus subgroup J, and the cloned Na
+
/H
+
exchanger 1 confers susceptibility on the otherwise resistant host. New World quails are also susceptible to new avian leukosis virus subgroup J variants but resistant to subgroups A and B and weakly susceptible to subgroups C and D of avian sarcoma/leukosis virus due to obvious defects of the respective receptors. Our results suggest that the avian leukosis virus subgroup J could be transmitted to New World quails and establish a natural reservoir of circulating virus with a potential for further evolution.

IMPORTANCE
Since its spread in broiler chickens in China and Southeast Asia in 2000, ALV-J remains a major enzootic challenge for the poultry industry. Although the virus diversifies rapidly in the poultry, its spillover and circulation in wild bird species has been prevented by the resistance of most species to ALV-J. It is, nevertheless, important to understand the evolution of the virus and its potential host range in wild birds. Because resistance to avian retroviruses is due particularly to receptor incompatibility, we studied Na
+
/H
+
exchanger 1, the receptor for ALV-J. In New World quails, we found a receptor compatible with virus entry, and we confirmed the susceptibilities of four New World quail species
in vitro
. We propose that a prospective molecular epidemiology study be conducted to identify species with the potential to become reservoirs for ALV-J.
Porcine Reproductive and Respiratory Syndrome Virus Antagonizes JAK/STAT3 Signaling via nsp5, Which Induces STAT3 Degradation
Authors: Yang Liping , Wang Rong , Ma Zexu , Xiao Yueqiang , Nan Yuchen , Wang Yu , Lin Shaoli , Zhang Yan-Jin 
Published: November 2016

ABSTRACT
Signal transducer and activator of transcription 3 (STAT3) is a pleiotropic signaling mediator of many cytokines, including interleukin-6 (IL-6) and IL-10. STAT3 is known to play critical roles in cell growth, proliferation, differentiation, immunity and inflammatory responses. The objective of this study was to determine the effect of porcine reproductive and respiratory syndrome virus (PRRSV) infection on the STAT3 signaling since PRRSV induces a weak protective immune response in host animals. We report here that PRRSV infection of MARC-145 cells and primary porcine pulmonary alveolar macrophages led to significant reduction of STAT3 protein level. Several strains of both PRRSV type 1 and type 2 led to a similar reduction of STAT3 protein level but had a minimal effect on its transcripts. The PRRSV-mediated STAT3 reduction was in a dose-dependent manner as the STAT3 level decreased, along with incremental amounts of PRRSV inocula. Further study showed that nonstructural protein 5 (nsp5) of PRRSV induced the STAT3 degradation by increasing its polyubiquitination level and shortening its half-life from 24 h to ∼3.5 h. The C-terminal domain of nsp5 was shown to be required for the STAT3 degradation. Moreover, the STAT3 signaling in the cells transfected with nsp5 plasmid was significantly inhibited. These results indicate that PRRSV antagonizes the STAT3 signaling by accelerating STAT3 degradation via the ubiquitin-proteasomal pathway. This study provides insight into the PRRSV interference with the JAK/STAT3 signaling, leading to perturbation of the host innate and adaptive immune responses.

IMPORTANCE
The typical features of immune responses in PRRSV-infected pigs are delayed onset and low levels of virus neutralizing antibodies, as well as weak cell-mediated immunity. Lymphocyte development and differentiation rely on cytokines, many of which signal through the JAK/STAT signaling pathway to exert their biological effects. Here, we discovered that PRRSV antagonizes the JAK/STAT3 signaling by inducing degradation of STAT3, a master transcription activator involved in multiple cellular processes and the host immune responses. The nsp5 protein of PRRSV is responsible for the accelerated STAT3 degradation. The PRRSV-mediated antagonizing STAT3 could lead to suppression of a broad spectrum of cytokines and growth factors to allow virus replication and spread in host animals. This may be one of the reasons for the PRRSV interference with the innate immunity and its poor elicitation of protective immunity. This finding provides insight into PRRSV pathogenesis and its interference with the host immune responses.
Risk factors for developing colorectal cancer in Japanese patients with ulcerative colitis: a retrospective observational study—CAPITAL (Cohort and Practice for IBD total management in Kyoto-Shiga Links) study I
Authors: Yoshino Takuya , Nakase Hiroshi , Takagi Tomohisa , Bamba Shigeki , Okuyama Yusuke , Kawamura Takuji , Oki Teruki , Obata Hirozumi , Kawanami Chiharu , Katsushima Shinji , Kusaka Toshihiro , Tsujikawa Tomoyuki , Naito Yuji , Andoh Akira , Kogawa Takafumi 
Published: November 2016

Background and AimsPatients with ulcerative colitis (UC) are at risk for developing colorectal cancer (CRC), despite the development of new therapeutic agents. Stratification of the individual UC-patient's risk would be helpful to validate the risk factors for CRC. The aim of this study was to evaluate the risk factors for the development of CRC in a large cohort of patients with UC.MethodsData were obtained from 12 hospitals in the Kyoto-Shiga region during 2003–2013. We performed a retrospective cohort study of 2137 patients with UC.ResultsIn total, 60 lesions of CRC were detected in 43 (2.0%) of 2137 patients. 30 of the 43 patients were male. The median age was 53 years. The median duration of disease was 13 years, and 67.4% of these patients had a disease duration >10 years. Of the 43 patients, 34 (79.1%) had extensive colitis. Primary sclerosing cholangitis was detected in 2 patients (4.7%). The median corticosteroids (CS) dose was 6.4 g, and 4 patients were treated with a total of more than 10 g of CS. 18 of these patients underwent more than 1 year CS treatment. Of all 60 CRC lesions, 43 (71.7%) were located in the distal colon and 35 (58.3%) were of the superficial type. Moreover, the stage of CRC was stage 0 or I in 55.8% of the 43 patients with CRC. Multivariate analysis suggested that extensive colitis could be a risk factor for the development of advanced CRC in patients with UC.ConclusionsOur findings indicated that male, extensive colitis, long-term duration of UC and family history of CRC, but not concomitant primary sclerosing cholangitis, are important factors for predicting CRC in Japanese patients with UC. Moreover, long-standing extensive colitis might contribute to the progression of CRC. Further studies are required to establish CRC surveillance in Japanese patients with UC.
Overview of phase IV clinical trials for postmarket drug safety surveillance: a status report from the ClinicalTrials.gov registry
Authors: Zhang Xinji , Zhang Yuan , Ye Xiaofei , Guo Xiaojing , Zhang Tianyi , He Jia 
Published: November 2016

ObjectivePhase IV trials are often used to investigate drug safety after approval. However, little is known about the characteristics of contemporary phase IV clinical trials and whether these studies are of sufficient quality to advance medical knowledge in pharmacovigilance. We aimed to determine the fundamental characteristics of phase IV clinical trials that evaluated drug safety using the ClinicalTrials.gov registry data.MethodsA data set of 19 359 phase IV clinical studies registered in ClinicalTrials.gov was downloaded. The characteristics of the phase IV trials focusing on safety only were compared with those evaluating both safety and efficacy. We also compared the characteristics of the phase IV trials in three major therapeutic areas (cardiovascular diseases, mental health and oncology). Multivariable logistic regression was used to evaluate factors associated with the use of blinding and randomisation.ResultsA total of 4772 phase IV trials were identified, including 330 focusing on drug safety alone and 4392 evaluating both safety and efficacy. Most of the phase IV trials evaluating drug safety (75.9%) had enrolment <300 with 96.5% <3000. Among these trials, 8.2% were terminated or withdrawn. Factors associated with the use of blinding and randomisation included the intervention model, clinical specialty and lead sponsor.ConclusionsPhase IV trials evaluating drug safety in the ClinicalTrials.gov registry were dominated by small trials that might not have sufficient power to detect less common adverse events. An adequate sample size should be emphasised for phase IV trials with safety surveillance as main task.