Exchange Protein Directly Activated by cAMP 2 Enhances Respiratory Syncytial Virus-Induced Pulmonary Disease in Mice.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in young children. It is also a significant contributor to upper respiratory tract infections, therefore, a major cause for visits to the pediatrician. High morbidity and mortality are associated with high-risk populations including premature infants, the elderly, and the immunocompromised.

The Importance of AGO 1 and 4 in Post-Transcriptional Gene Regulatory Function of tRF5-GluCTC, an Respiratory Syncytial Virus-Induced tRNA-Derived RNA Fragment.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants, the elderly, and immune-compromised patients. It is also a significant contributor to upper respiratory tract infection in the pediatric population. However, its disease mechanisms are still largely unknown.

A tRNA-derived RNA Fragment Plays an Important Role in the Mechanism of Arsenite -induced Cellular Responses.

Chronic exposure to environmental heavy metals is a worldwide health concern. It is acknowledged to be an important cause of lower respiratory tract damage in children. However, the molecular mechanisms underlying the heavy metal-induced cellular stress/toxicity are not completely understood.

Exchange Proteins Directly Activated by cAMP and Their Roles in Respiratory Syncytial Virus Infection.

Respiratory syncytial virus (RSV) is the leading cause of respiratory infection in young children and high-risk adults. However, a specific treatment for this viral infection is not currently available. In this study, we discovered that an exchange protein directly activated by cyclic AMP (EPAC) can serve as a potential therapeutic target for RSV.

The Linear Ubiquitin Assembly Complex Modulates Latent Membrane Protein 1 Activation of NF-κB and Interferon Regulatory Factor 7.

Unlabelled: Recently, linear ubiquitin assembly complex (LUBAC)-mediated linear ubiquitination has come into focus due to its emerging role in activation of NF-κB in different biological contexts. However, the role of LUBAC in LMP1 signaling leading to NF-κB and interferon regulatory factor 7 (IRF7) activation has not been investigated. We show here that RNF31, the key component of LUBAC, interacts with LMP1 and IRF7 in Epstein-Barr virus (EBV)-transformed cells and that LUBAC stimulates linear ubiquitination of NEMO and IRF7.

Protein phosphatase 1 abrogates IRF7-mediated type I IFN response in antiviral immunity.

Interferon (IFN) regulatory factor 7 (IRF7) plays a key role in the production of IFN-α in response to viral infection, and phosphorylation at IRF7 C-terminal serine sites is prelude to its function. However, phosphatases that negatively regulate IRF7 phosphorylation and activity have not been reported. In this study, we have identified a conserved protein phosphatase 1 (PP1)-binding motif in human and mouse IRF7 proteins, and shown that PP1 physically interacts with IRF7.

Mitochondrial antiviral-signalling protein plays an essential role in host immunity against human metapneumovirus.

Human metapneumovirus (hMPV) is a common cause of respiratory tract infection in the paediatrics population. Recently, we and others have shown that retinoic acid-inducible gene 1 (RIG-I)-like receptors (RLRs) are essential for hMPV-induced cellular antiviral signalling. However, the contribution of those receptors to host immunity against pulmonary hMPV infection is largely unexplored.

Human metapneumovirus M2-2 protein inhibits innate immune response in monocyte-derived dendritic cells.

Human metapneumovirus (hMPV) is a leading cause of lower respiratory infection in young children, the elderly and immunocompromised patients. Repeated hMPV infections occur throughout life. However, immune evasion mechanisms of hMPV infection are largely unknown.

MyD88 controls human metapneumovirus-induced pulmonary immune responses and disease pathogenesis.

Human metapneumovirus (hMPV) is a common cause of lung and airway infections in infants and young children. Recently, we and others have shown that hMPV infection induces Toll-like receptor (TLR)-dependent cellular signaling. However, the contribution of TLR-mediated signaling in host defenses against pulmonary hMPV infection and associated disease pathogenesis has not been elucidated.

Human metapneumovirus glycoprotein G disrupts mitochondrial signaling in airway epithelial cells.

Human metapneumovirus (hMPV) is a recently identified RNA virus belonging to the Paramyxoviridae family. It is a common cause of respiratory tract infections in children, adults, and immunocompromised patients, for which no specific treatment or vaccine is available. Recent investigations in our lab identified hMPV glycoprotein G as an important virulence factor, as a recombinant virus lacking the G protein (rhMPV-ΔG) exhibited enhanced production of important immune and antiviral mediators, such as cytokines, chemokines and type I interferon (IFN) in airway epithelial cells, and expression of G protein alone inhibits cellular signaling dependent on retinoic induced gene (RIG)-I, a RNA helicase with a fundamental role in initiating hMPV-induced cellular responses.

Identification and functional characterization of tRNA-derived RNA fragments (tRFs) in respiratory syncytial virus infection.

The discovery of small noncoding RNAs (sncRNAs) with regulatory functions is a recent breakthrough in biology. Among sncRNAs, microRNA (miRNA), derived from host or virus, has emerged as elements with high importance in control of viral replication and host responses. However, the expression pattern and functional aspects of other types of sncRNAs, following viral infection, are unexplored.

Human metapneumovirus M2-2 protein inhibits innate cellular signaling by targeting MAVS.

Human metapneumovirus (hMPV) is a leading cause of respiratory infections in pediatric populations globally, with no prophylactic or therapeutic measures. Recently, a recombinant hMPV lacking the M2-2 protein (rhMPV-ΔM2-2) demonstrated reduced replication in the respiratory tract of animal models, making it a promising live vaccine candidate. However, the exact nature of the interaction between the M2-2 protein and host cells that regulates viral infection/propagation is largely unknown.

Human metapneumovirus inhibits IFN-β signaling by downregulating Jak1 and Tyk2 cellular levels.

Human metapneumovirus (hMPV), a leading cause of respiratory tract infections in infants, inhibits type I interferon (IFN) signaling by an unidentified mechanism. In this study, we showed that infection of airway epithelial cells with hMPV decreased cellular level of Janus tyrosine kinase (Jak1) and tyrosine kinase 2 (Tyk2), due to enhanced proteosomal degradation and reduced gene transcription. In addition, hMPV infection also reduced the surface expression of type I IFN receptor (IFNAR).

A novel mechanism for the inhibition of interferon regulatory factor-3-dependent gene expression by human respiratory syncytial virus NS1 protein.

Human respiratory syncytial virus (RSV), a leading cause of respiratory tract infections in infants, inhibits type I interferon (IFN)-dependent signalling, as well as IFN synthesis. RSV non-structural protein NS1 plays a significant role in this inhibition; however, the mechanism(s) responsible is not fully known. The transcription factor interferon regulatory factor (IRF)-3 is essential for viral-induced IFN-β synthesis.

Identification of a mutated BHK-21 cell line that became less susceptible to Japanese encephalitis virus infection.

The pathogenesis of Japanese encephalitis virus (JEV) is not definitely elucidated as the initial interaction between virus and host cell receptors required for JEV infection is not clearly defined yet. Here, in order to discover those membrane proteins that may be involved in JEV attachment to or entry into virus permissive BHK-21 cells, a chemically mutated cell line (designated 3A10-3F) that became less susceptible to JEV infection was preliminarily established and selected by repeated low moi JEV challenges and RT-PCR detection for viral RNA E gene fragment. The susceptibility to JEV of 3A10-3F cells was significantly weakened compared with parental BHK-21 cells, verified by indirect immunofluorescence assay, virus plague formation assay, and flow cytometry.

Localization of West Nile Virus in monkey brain: double staining antigens immunohistochemically of neurons, neuroglia cells and West Nile Virus.

West Nile virus (WNV) can cause encephalitis or meningitis that affects brain tissue, which can also lead to permanent neurological damage that can be fatal. To our knowledge, no consistent double immunohistochemical staining of neurons, neuroglia cells, and WNV has yet been reported. To establish a method for performing double-label immunohistochemical detection of neurons, neuroglia cells and WNV, examining the pathological characteristics of WNV-infected neurons, neuroglia cells, and investigating distribution of WNV in monkey brain, paraffin-embedded monkey brain tissue were retrospectively studied by immunohistochemical staining of neurons, neuroglia cells and WNV.

Non-structural and nucleocapsid proteins of Punta Toro virus induce apoptosis of hepatocytes through both intrinsic and extrinsic pathways.

Punta Toro virus (PTV; family Bunyaviridae, genus Phlebovirus) causes severe hepatic damage through brisk apoptosis of hepatocytes. In the present study, two viral proteins encoded by the S segment of the viral genome, non-structural (NSs) and nucleocapsid protein (N), were examined for their roles in apoptosis. Expression of NSs in HepG2 cells led to apoptosis in 45% of transfected cells, and with N, 28%, on average.

Does Japanese encephalitis virus share the same cellular receptor with other mosquito-borne flaviviruses on the C6/36 mosquito cells?

Japanese encephalitis virus (JEV) is a member of mosquito-borne Flaviviridae. To date, the mechanisms of the early events of JEV infection remain poorly understood, and the cellular receptors are unidentified. There are evidences that the structure of the virus attachment proteins (VAP), envelope glycoprotein of mosquito-borne flaviviruses is very similar, and the vector-virus interaction of mosquito-borne flaviviruses is also very similar.

Characterization of truncated hantavirus nucleocapsid proteins and their application for serotyping.

Hemorrhagic fever with renal syndrome (HFRS) is a fulminant infectious disease characterized by fever, hemorrhage, renal impairment, and thrombocytopenia. Hantaviruses associated with this belong to different serotypes: Hantaan (HTN), Seoul (SEO), Dobrava/Belgrade (DOB), and Puumala (PUU). The first two, HTN and SEO, are endemic in China.

[Preparation, characterization and preliminary application of monoclonal antibody against human mu chain].

Aim: To prepare monoclonal antibody (mAb) against human mu chain with high titer and establish a capture ELISA for early serological diagnosis of infectious diseases.

Methods: BALB/c mice were immunized with human IgM. Hybridoma cell line which could stably secret the mAb to human IgM was established by routine cell fusion technique.

[Preparation of specific monoclonal antibody against nucleocapsid protein of SARS coronavirus].

Aim: To express nucleocapsid(N) protein of SARS coronavirus and produce monoclonal antibody(mAb) to N protein.

Methods: N protein gene was amplified by RT-PCR. After being confirmed by DNA sequencing, the gene was subcloned into prokaryotic expression vector.

[Analysis on patial amino acid sequence of a novel glycoprotein binding to antiherpes simplex virus monoclonal antibody CHA9].

Aim: To acquire the characteristic amino acid sequence of a novel glycoprotein of herpes simplex virus (HSV), so as to localize gene encoding the novel glycoprotein accurately.

Methods: A 12-mer phage peptide library was screened for 3 rounds by using biotinylated mAb CHA9 against new glycoprotein g30k of HSV-2. Positive phage clones were detected by ELISA.

[Expression of Japanese encephalitis virus E protein in methylotrophic yeast Pichia pastoris].

Aim: To express Japanese encephalitis virus (JEV) E protein in methylotrophic yeast Pichia pastoris.

Methods: The gene coding for JEV E protein was sub-cloned into vector pPIC9k. The constructed plasmid was transformed into yeast SMD1168 by electroporation.

[Expression of hepatitis C virus envelope proteins with a recombinant baculovirus expression system].

Objective: To acquire stable expression of envelope proteins of hepatitis C virus in insect host cells and use the expressed envelope proteins for detecting the serums of patients with hepatitis C.

Methods: The envelope gene of HCV H strain was amplified by PCR and inserted in baculovirus vector BacPAK8, and then recombined with linear BacPAK6 DNA in insect cells. The recombinant baculoviruses were selected by the plaque assay.