Publications by authors named "Yoshiharu Matsuura"

237 Publications

Engineered ACE2 receptor therapy overcomes mutational escape of SARS-CoV-2.

Nat Commun 2021 06 21;12(1):3802. Epub 2021 Jun 21.

Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.

SARS-CoV-2 has mutated during the global pandemic leading to viral adaptation to medications and vaccinations. Here we describe an engineered human virus receptor, ACE2, by mutagenesis and screening for binding to the receptor binding domain (RBD). Three cycles of random mutagenesis and cell sorting achieved sub-nanomolar affinity to RBD. Our structural data show that the enhanced affinity comes from better hydrophobic packing and hydrogen-bonding geometry at the interface. Additional disulfide mutations caused the fixing of a closed ACE2 conformation to avoid off-target effects of protease activity, and also improved structural stability. Our engineered ACE2 neutralized SARS-CoV-2 at a 100-fold lower concentration than wild type; we also report that no escape mutants emerged in the co-incubation after 15 passages. Therapeutic administration of engineered ACE2 protected hamsters from SARS-CoV-2 infection, decreased lung virus titers and pathology. Our results provide evidence of a therapeutic potential of engineered ACE2.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-24013-yDOI Listing
June 2021

Combining machine learning and nanopore construction creates an artificial intelligence nanopore for coronavirus detection.

Nat Commun 2021 06 17;12(1):3726. Epub 2021 Jun 17.

Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.

High-throughput, high-accuracy detection of emerging viruses allows for the control of disease outbreaks. Currently, reverse transcription-polymerase chain reaction (RT-PCR) is currently the most-widely used technology to diagnose the presence of SARS-CoV-2. However, RT-PCR requires the extraction of viral RNA from clinical specimens to obtain high sensitivity. Here, we report a method for detecting novel coronaviruses with high sensitivity by using nanopores together with artificial intelligence, a relatively simple procedure that does not require RNA extraction. Our final platform, which we call the artificially intelligent nanopore, consists of machine learning software on a server, a portable high-speed and high-precision current measuring instrument, and scalable, cost-effective semiconducting nanopore modules. We show that artificially intelligent nanopores are successful in accurately identifying four types of coronaviruses similar in size, HCoV-229E, SARS-CoV, MERS-CoV, and SARS-CoV-2. Detection of SARS-CoV-2 in saliva specimen is achieved with a sensitivity of 90% and specificity of 96% with a 5-minute measurement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-24001-2DOI Listing
June 2021

An infectivity-enhancing site on the SARS-CoV-2 spike protein targeted by antibodies.

Cell 2021 May 24. Epub 2021 May 24.

Department of Health Development and Medicine, Graduate school of Medicine, Osaka University, Osaka 565-0871, Japan.

Antibodies against the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein prevent SARS-CoV-2 infection. However, the effects of antibodies against other spike protein domains are largely unknown. Here, we screened a series of anti-spike monoclonal antibodies from coronavirus disease 2019 (COVID-19) patients and found that some of antibodies against the N-terminal domain (NTD) induced the open conformation of RBD and thus enhanced the binding capacity of the spike protein to ACE2 and infectivity of SARS-CoV-2. Mutational analysis revealed that all of the infectivity-enhancing antibodies recognized a specific site on the NTD. Structural analysis demonstrated that all infectivity-enhancing antibodies bound to NTD in a similar manner. The antibodies against this infectivity-enhancing site were detected at high levels in severe patients. Moreover, we identified antibodies against the infectivity-enhancing site in uninfected donors, albeit at a lower frequency. These findings demonstrate that not only neutralizing antibodies but also enhancing antibodies are produced during SARS-CoV-2 infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cell.2021.05.032DOI Listing
May 2021

Hepatitis C virus modulates signal peptide peptidase to alter host protein processing.

Proc Natl Acad Sci U S A 2021 Jun;118(22)

Institute for Advanced Co-Creation Studies, Osaka University, Osaka, 565-0871, Japan;

Immunoevasins are viral proteins that prevent antigen presentation on major histocompatibility complex (MHC) class I, thus evading host immune recognition. Hepatitis C virus (HCV) evades immune surveillance to induce chronic infection; however, how HCV-infected hepatocytes affect immune cells and evade immune recognition remains unclear. Herein, we demonstrate that HCV core protein functions as an immunoevasin. Its expression interfered with the maturation of MHC class I molecules catalyzed by the signal peptide peptidase (SPP) and induced their degradation via HMG-CoA reductase degradation 1 homolog, thereby impairing antigen presentation to CD8 T cells. The expression of MHC class I in the livers of HCV core transgenic mice and chronic hepatitis C patients was impaired but was restored in patients achieving sustained virological response. Finally, we show that the human cytomegalovirus US2 protein, possessing a transmembrane region structurally similar to the HCV core protein, targets SPP to impair MHC class I molecule expression. Thus, SPP represents a potential target for the impairment of MHC class I molecules by DNA and RNA viruses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2026184118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8179148PMC
June 2021

Establishment of a Cell Culture Model Permissive for Infection by Hepatitis B and C Viruses.

Hepatol Commun 2021 Apr 19;5(4):634-649. Epub 2020 Dec 19.

Department of Microbiology Graduate School of Medical Science University of Yamanashi Yamanashi Japan.

Compared with each monoinfection, coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) is well known to increase the risks of developing liver cirrhosis and hepatocellular carcinoma. However, the mechanism by which HBV/HCV coinfection is established in hepatocytes is not well understood. Common cell culture models for coinfection are required to examine viral propagation. In this study, we aimed to establish a cell line permissive for both HBV and HCV infection. We first prepared a HepG2 cell line expressing sodium taurocholate cotransporting polypeptide, an HBV receptor, and then selected a cell line highly permissive for HBV infection, G2/NT18-B. After transduction with a lentivirus-encoding microRNA-122, the cell line harboring the highest level of replicon RNA was selected and then treated with anti-HCV compounds to eliminate the replicon RNA. The resulting cured cell line was transduced with a plasmid-encoding CD81. The cell line permissive for HCV infection was cloned and then designated the G2BC-C2 cell line, which exhibited permissiveness for HBV and HCV propagation. JAK inhibitor I potentiated the HCV superinfection of HBV-infected cells, and fluorescence-activated cell-sorting analysis indicated that HBV/HCV double-positive cells accounted for approximately 30% of the coinfected cells. Among several host genes tested, cyclooxygenase-2 showed synergistic induction by coinfection compared with each monoinfection. These data indicate that our HBV/HCV coinfection system provides an easy-to-use platform for the study of host and viral responses against coinfection and the development of antiviral agents targeting HBV and HCV.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep4.1653DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8034569PMC
April 2021

Establishment of a reverse genetics system for SARS-CoV-2 using circular polymerase extension reaction.

Cell Rep 2021 04 1;35(3):109014. Epub 2021 Apr 1.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan; Center for Infectious Diseases Education and Research, Osaka University, Suita, Osaka 565-0871, Japan. Electronic address:

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the causative agent of coronavirus disease 2019 (COVID-19). Although multiple mutations have been observed in SARS-CoV-2, functional analysis of each mutation of SARS-CoV-2 has been limited by the lack of convenient mutagenesis methods. In this study, we establish a PCR-based, bacterium-free method to generate SARS-CoV-2 infectious clones. Recombinant SARS-CoV-2 could be rescued at high titer with high accuracy after assembling 10 SARS-CoV-2 cDNA fragments by circular polymerase extension reaction (CPER) and transfection of the resulting circular genome into susceptible cells. The construction of infectious clones for reporter viruses and mutant viruses could be completed in two simple steps: introduction of reporter genes or mutations into the desirable DNA fragments (∼5,000 base pairs) by PCR and assembly of the DNA fragments by CPER. This reverse genetics system may potentially advance further understanding of SARS-CoV-2.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2021.109014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8015404PMC
April 2021

SARS-CoV-2-induced humoral immunity through B cell epitope analysis in COVID-19 infected individuals.

Sci Rep 2021 03 15;11(1):5934. Epub 2021 Mar 15.

Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Suita, Japan.

The aim of this study is to understand adaptive immunity to SARS-CoV-2 through the analysis of B cell epitope and neutralizing activity in coronavirus disease 2019 (COVID-19) patients. We obtained serum from forty-three COVID-19 patients from patients in the intensive care unit of Osaka University Hospital (n = 12) and in Osaka City Juso Hospital (n = 31). Most individuals revealed neutralizing activity against SARS-CoV-2 assessed by a pseudotype virus-neutralizing assay. The antibody production against the spike glycoprotein (S protein) or receptor-binding domain (RBD) of SARS-CoV-2 was elevated, with large individual differences, as assessed by ELISA. We observed the correlation between neutralizing antibody titer and IgG, but not IgM, antibody titer of COVID-19 patients. In the analysis of the predicted the linear B cell epitopes, hot spots in the N-terminal domain of the S protein were observed in the serum from patients in the intensive care unit of Osaka University Hospital. Overall, the analysis of antibody production and B cell epitopes of the S protein from patient serum may provide a novel target for the vaccine development against SARS-CoV-2.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-85202-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7960719PMC
March 2021

Suppression of optineurin impairs the progression of hepatocellular carcinoma through regulating mitophagy.

Cancer Med 2021 03 18;10(5):1501-1514. Epub 2021 Feb 18.

Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.

Autophagy removes damaged organelles to inhibit malignant transformation during tumor initiation. Once a cancer matures, it uses the autophagic pathway as an energy source. Optineurin (OPTN) is an autophagy adaptor protein that recruits microtubule-associated protein 1 light chain 3, an autophagosome marker, to the autophagosome. Despite studies of the relation between cancer progression and autophagy adaptor proteins, there are no reports to our knowledge of a correlation between hepatocellular carcinoma (HCC) and OPTN. We aimed here to investigate the effects of OPTN expression on HCC progression through autophagy. Immunohistochemistry was used to measure the OPTN expression in the tissues of 141 Japanese patients with HCC. The effects of OPTN expression on HCC progression and mitophagy were assessed using an OPTN knockout (KO) cell line in vitro. We used this KO cell line to establish and exploit a mouse model of HCC to determine the effects of OPTN expression on tumor progression. Immunohistochemical analysis showed that patients with elevated expression of OPTN experienced shorter overall survival (OS) and recurrence-free survival (RFS). OPTN KO cells proliferated relatively slower versus wild-type (WT) cells in vitro. Western blot analysis showed that mitophagy was suppressed in OPTN KO cells, and ATP synthesis and beta-oxidation were reduced. The mouse model of HCC showed that OPTN KO cells formed smaller tumors versus WT cells less 10 weeks after implantation. Overall, the present findings suggest that OPTN is a key mediator of mitophagy that contributes to HCC progression through mitochondrial energy production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cam4.3519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7940236PMC
March 2021

Deneddylation by SENP8 restricts hepatitis B virus propagation.

Microbiol Immunol 2021 Mar 24;65(3):125-135. Epub 2021 Feb 24.

Institute for Advanced Co-Creation Studies, Research, Institute for Microbial Diseases, Osaka University, Suita, Japan.

Proteins newly synthesized from messenger RNA undergo Posttranslational modifications (PTMs) such as phosphorylation, glycosylation, methylation, and ubiquitination. These PTMs have important roles in protein stability, localization, and conformation and have been reported to be involved in hepatitis B virus (HBV) propagation. Although ubiquitination plays an essential role in HBV life cycles, the involvement of ubiquitin-like proteins (UBLs) in HBV life cycles has been understudied. Through comprehensive gain- and loss-of-function screening of UBLs, we observed that neddylation, a PTM in which neural precursor cell, expressed developmentally downregulated 8 (NEDD8) is conjugated to substrate proteins, was required for efficient HBV propagation. We also found that overexpression of sentrin-specific protease 8 (SENP8), which cleaves conjugated NEDD8, suppressed HBV propagation. Further, the catalytic activity of SENP8 was required for the suppression of HBV propagation. These results indicated that the reduction of neddylation negatively regulated HBV propagation. In addition, we demonstrated that suppression of HBV propagation via SENP8 overexpression was independent of hepatitis B protein X (HBx) and HBV promoter activity. Therefore, our data suggested that neddylation plays an important role in the late stages of HBV life cycles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1348-0421.12874DOI Listing
March 2021

Ponesimod suppresses hepatitis B virus infection by inhibiting endosome maturation.

Antiviral Res 2021 02 18;186:104999. Epub 2020 Dec 18.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, 565-0871, Japan. Electronic address:

The discovery of novel antivirals to treat hepatitis B virus (HBV) infection is urgently needed, as the currently available drugs mainly target viral proteins at replication step, whereas host factors also play significant roles in HBV infection. Although numerous studies have reported candidate drugs for HBV treatment, there remains a need to find a new drug that may target other steps of the HBV life cycle. In this study, by drug screening of a 533 G-protein-coupled receptors (GPCRs)-associated compound library, we identified ponesimod, a selective agonist of sphingosine-1-phosphate receptor 1 (S1P), as a drug candidate for the suppression of HBV infection. However, the anti-HBV effect of ponesimod is independent of S1P and other sphingosine-1-phosphate receptors (S1PRs). Treatment with ponesimod at an early step of infection but not at a post-entry step significantly reduced the HBV relaxed circular DNA (rcDNA) level in a dose-dependent manner. Ponesimod treatment did not inhibit attachment, binding, or internalization of HBV particles via endocytosis through an interaction with sodium taurocholate cotransporting polypeptide (NTCP) or epidermal growth factor receptor (EGFR). Importantly, during the transportation of HBV particles to the nucleus, co-localization of HBV with early endosomes but not with late endosomes and lysosomes was induced by the treatment with ponesimod, suggesting that ponesimod interferes with the conversion of early endosomes to late endosomes without significant damage to cellular growth. Conclusion: Ponesimod is a promising anti-HBV drug targeting the endosome maturation of HBV. This finding can be applied to the development of novel antivirals that target the trafficking pathway of HBV particles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.antiviral.2020.104999DOI Listing
February 2021

Induction of HOX Genes by Hepatitis C Virus Infection via Impairment of Histone H2A Monoubiquitination.

J Virol 2021 02 24;95(6). Epub 2021 Feb 24.

Department of Microbiology, Faculty of Medicine, Graduate Faculty of Interdisciplinary Research, University of Yamanashi, Yamanashi, Japan

Hepatitis C virus (HCV) infection causes liver pathologies, including hepatocellular carcinoma (HCC). Homeobox (HOX) gene products regulate embryonic development and are associated with tumorigenesis, although the regulation of HOX genes by HCV infection has not been clarified in detail. We examined the effect of HCV infection on HOX gene expression. In this study, HCV infection induced more than half of the HOX genes and reduced the level of histone H2A monoubiquitination on lysine 119 (K119) (H2Aub), which represses HOX gene promoter activity. HCV infection also promoted proteasome-dependent degradation of RNF2, which is an E3 ligase mediating H2A monoubiquitination as a component of polycomb repressive complex 1. Since full-genomic replicon cells but not subgenomic replicon cells exhibited reduced RNF2 and H2Aub levels and induction of HOX genes, we focused on the core protein. Expression of the core protein reduced the amounts of RNF2 and H2Aub and induced HOX genes. Treatment with LY-411575, which can reduce HCV core protein expression via signal peptide peptidase (SPP) inhibition without affecting other viral proteins, dose-dependently restored the amounts of RNF2 and H2Aub in HCV-infected cells and impaired the induction of HOX genes and production of viral particles but not viral replication. The chromatin immunoprecipitation assay results also indicated infection- and proteasome-dependent reductions in H2Aub located in HOX gene promoters. These results suggest that HCV infection or core protein induces HOX genes by impairing histone H2A monoubiquitination via a reduction in the RNF2 level. Recently sustained virologic response can be achieved by direct-acting antiviral (DAA) therapy in most hepatitis C patients. Unfortunately, DAA therapy does not completely eliminate a risk of hepatocellular carcinoma (HCC). Several epigenetic factors, including histone modifications, are well known to contribute to hepatitis C virus (HCV)-associated HCC. However, the regulation of histone modifications by HCV infection has not been clarified in detail. In this study, our data suggest that HCV infection or HCV core protein expression impairs monoubiquitination of histone H2A K119 in the homeobox (HOX) gene promoter via destabilization of RNF2 and then induces HOX genes. Several lines of evidence suggest that the expression of several HOX genes is dysregulated in certain types of tumors. These findings reveal a novel mechanism of HCV-related histone modification and may provide information about new targets for diagnosis and prevention of HCC occurrence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01784-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8094938PMC
February 2021

Identification of GII.14[P7] norovirus and its genomic mutations from a case of long-term infection in a post-symptomatic individual.

Infect Genet Evol 2020 12 1;86:104612. Epub 2020 Nov 1.

Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand. Electronic address:

Norovirus is a leading cause of acute gastroenteritis worldwide. Norovirus shedding typically lasts one week to one month after the onset of diarrhea in immunocompetent hosts. The occurrence of mutations in the genome during infection has contributed to the evolution of norovirus. It has been suggested that genomic mutations in the P2-domain of capsid protein VP1, the major antigenic site for virus clearance, are involved in the evasion of host immunity and prolonged shedding of norovirus. In our previous study, we found a case of long-term shedding of GII.14 norovirus in a post-symptomatic immunocompetent individual that lasted about three months. In this study, we characterized the genomic sequence of the GII.14 strain to gain insight into the context of long-term shedding. By sequencing a 4.8 kb region of the genome corresponding to half of ORF1 and the entire ORF2 and ORF3, which encode several non-structural proteins and the structural proteins VP1 and VP2, the GII.14 strain was found to be classified as recombinant GII.14[P7]. Six point-mutations occurred during the three-month period of infection in a time-dependent manner in the genomic regions encoding RNA-dependent RNA polymerase, VP1, and VP2. Three of the six mutations were sense mutations, but no amino acid substitution was identified in the P2-domain of VP1. These results suggest that there is a mechanism by which long-term shedding of norovirus occurs in immunocompetent individuals independent of P2-domain mutations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.meegid.2020.104612DOI Listing
December 2020

Generation of Genetically RGD σ1-Modified Oncolytic Reovirus That Enhances JAM-A-Independent Infection of Tumor Cells.

J Virol 2020 11 9;94(23). Epub 2020 Nov 9.

Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan

Mammalian reovirus (MRV) strain type 3 Dearing (T3D) is a naturally occurring oncolytic virus that has been developed as a potential cancer therapeutic. However, MRV treatment cannot be applied to cancer cells expressing low levels of junctional adhesion molecule A (JAM-A), which is the entry receptor of MRV. In this study, we developed a reverse genetics system for MRV strain T3D-L, which showed high oncolytic potency. To modify the cell tropism of MRV, an arginine-glycine-aspartic acid (RGD) peptide with an affinity to integrin was inserted at the C terminus or loop structures of the viral cell attachment protein σ1. The recombinant RGD σ1-modified viruses induced remarkable cell lysis in human cancer cell lines with marginal JAM-A expression and in JAM-A knockout cancer cell lines generated by a CRISPR/Cas9 system. Pretreatment of cells with anti-integrin antibody decreased cell death caused by the RGD σ1-modified virus, suggesting the infection to the cells was via a specific interaction with integrin αV. By using mouse models, we assessed virulence of the RGD σ1-modified viruses This system will open new avenues for the use of genetically modified oncolytic MRV for use as a cancer therapy. Oncolytic viruses kill tumors without affecting normal cells. A variety of oncolytic viruses are used as cancer therapeutics. Mammalian reovirus (MRV), which belongs to the genus , family , is one such natural oncolytic virus. The anticancer effects of MRV are being evaluated in clinical trials. Unlike other oncolytic viruses, MRV has not been genetically modified for use as a cancer therapeutic in clinical trials. Here, we used a reverse genetic approach to introduce an integrin-affinity peptide sequence into the MRV cell attachment protein σ1 to alter the natural tropism of the virus. The recombinant viruses were able to infect cancer cell lines expressing very low levels of the MRV entry receptor, junctional adhesion molecule A (JAM-A), and cause tumor cell death while maintaining its original tropism via JAM-A. This is a novel report of a genetically modified oncolytic MRV by introducing a peptide sequence into σ1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01703-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7654265PMC
November 2020

IL-6 trans-signaling induces plasminogen activator inhibitor-1 from vascular endothelial cells in cytokine release syndrome.

Proc Natl Acad Sci U S A 2020 09 21;117(36):22351-22356. Epub 2020 Aug 21.

Department of Immune Regulation, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan;

Cytokine release syndrome (CRS) is a life-threatening complication induced by systemic inflammatory responses to infections, including bacteria and chimeric antigen receptor T cell therapy. There are currently no immunotherapies with proven clinical efficacy and understanding of the molecular mechanisms of CRS pathogenesis is limited. Here, we found that patients diagnosed with CRS from sepsis, acute respiratory distress syndrome (ARDS), or burns showed common manifestations: strikingly elevated levels of the four proinflammatory cytokines interleukin (IL)-6, IL-8, monocyte chemotactic protein-1 (MCP-1), and IL-10 and the coagulation cascade activator plasminogen activator inhibitor-1 (PAI-1). Our in vitro data indicate that endothelial IL-6 trans-signaling formed an inflammation circuit for robust IL-6, IL-8, and MCP-1 production and promoted PAI-1 production; additionally, an IL-6 signaling blockade by the human monoclonal antibody tocilizumab blunted endothelial cell activation. Plasma from severe COVID-19 patients similarly exhibited increased IL-6, IL-10, and MCP-1 levels, but these levels were not as high as those in patients with CRS from other causes. In contrast, the PAI-1 levels in COVID-19 patients were as highly elevated as those in patients with bacterial sepsis or ARDS. Tocilizumab treatment decreased the PAI-1 levels and alleviated critical illness in severe COVID-19 patients. Our findings suggest that distinct levels of cytokine production are associated with CRS induced by bacterial infection and COVID-19, but both CRS types are accompanied by endotheliopathy through IL-6 trans-signaling. Thus, the present study highlights the crucial role of IL-6 signaling in endothelial dysfunction during bacterial infection and COVID-19.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2010229117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486751PMC
September 2020

ISGylation of Hepatitis C Virus NS5A Protein Promotes Viral RNA Replication via Recruitment of Cyclophilin A.

J Virol 2020 09 29;94(20). Epub 2020 Sep 29.

Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan

Interferon-stimulated gene 15 (ISG15) is a ubiquitin-like protein that is covalently conjugated to many substrate proteins in order to modulate their functions; this conjugation is called ISGylation. Several groups reported that the ISGylation of hepatitis C virus (HCV) NS5A protein affects HCV replication. However, the ISG15 conjugation sites on NS5A are not well determined, and it is unclear whether the role of NS5A ISGylation in HCV replication is proviral or antiviral. Here, we investigated the role of NS5A ISGylation in HCV replication by using HCV RNA replicons that encode a mutation at each lysine (Lys) residue of the NS5A protein. Immunoblot analyses revealed that 5 Lys residues (K44, K68, K166, K215, and K308) of the 14 Lys residues within NS5A (genotype 1b, Con1) have the potential to accept ISGylation. We tested the NS5A ISGylation among different HCV genotypes and observed that the NS5A proteins of all of the HCV genotypes accept ISGylation at multiple Lys residues. Using an HCV luciferase reporter replicon assay revealed that residue K308 of NS5A is important for HCV (1b, Con1) RNA replication. We observed that K308, one of the Lys residues for NS5A ISGylation, is located within the binding region of cyclophilin A (CypA), which is the critical host factor for HCV replication. We obtained evidence derived from all of the HCV genotypes suggesting that NS5A ISGylation enhances the interaction between NS5A and CypA. Taken together, these results suggest that NS5A ISGylation functions as a proviral factor and promotes HCV replication via the recruitment of CypA. Host cells have evolved host defense machinery (such as innate immunity) to eliminate viral infections. Viruses have evolved several counteracting strategies for achieving an immune escape from host defense machinery, including type I interferons (IFNs) and inflammatory cytokines. ISG15 is an IFN-inducible ubiquitin-like protein that is covalently conjugated to the viral protein via specific Lys residues and suppresses viral functions and viral propagation. Here, we demonstrate that HCV NS5A protein accepts ISG15 conjugation at specific Lys residues and that the HERC5 E3 ligase specifically promotes NS5A ISGylation. We obtained evidence suggesting that NS5A ISGylation facilitates the recruitment of CypA, which is the critical host factor for HCV replication, thereby promoting HCV replication. These findings indicate that E3 ligase HERC5 is a potential therapeutic target for HCV infection. We propose that HCV hijacks an intracellular ISG15 function to escape the host defense machinery in order to establish a persistent infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.00532-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527057PMC
September 2020

Norovirus transmission mediated by asymptomatic family members in households.

PLoS One 2020 23;15(7):e0236502. Epub 2020 Jul 23.

Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Nonthaburi, Thailand.

The transmission of human norovirus excreted from infected persons occasionally causes sporadic infections and outbreaks. Both symptomatic patients and asymptomatic carriers have been reported to contribute to norovirus transmission, but little is known about the magnitude of the contribution of asymptomatic carriers. We carried out a 1-year survey of residents of a district of Bangkok, Thailand to determine the percentage of norovirus transmissions originating from asymptomatic individuals. We screened 38 individuals recruited from 16 families from May 2018 to April 2019 for GI and GII genotypes. Norovirus was detected every month, and 101 of 716 stool samples (14.1%) from individuals with no symptoms of acute gastroenteritis were norovirus-positive. The average infection frequency was 2.4 times per person per year. Fourteen genotypes were identified from the positive samples, with GII.4 being detected most frequently. Notably, 89.1% of the norovirus-positive samples were provided by individuals with no diarrhea episode. Similar to cases of symptomatic infections in Thailand, asymptomatic infections were observed most frequently in December. We detected 4 cases of NV infection caused by household transmission, and 3 of the 4 transmissions originated from asymptomatic individuals. We also identified a case in which norovirus derived from an asymptomatic individual caused diarrhea in a family member. These results suggest that asymptomatic individuals play a substantial role in both the maintenance and spreading of norovirus in a community through household transmission.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236502PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7377487PMC
September 2020

Anti-Chikungunya Virus Monoclonal Antibody That Inhibits Viral Fusion and Release.

J Virol 2020 09 15;94(19). Epub 2020 Sep 15.

Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI), Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand

Chikungunya fever, a mosquito-borne disease manifested by fever, rash, myalgia, and arthralgia, is caused by chikungunya virus (CHIKV), which belongs to the genus of the family Anti-CHIKV IgG from convalescent patients is known to directly neutralize CHIKV, and the state of immunity lasts throughout life. Here, we examined the epitope of a neutralizing mouse monoclonal antibody against CHIKV, CHE19, which inhibits viral fusion and release. docking analysis showed that the epitope of CHE19 was localized in the viral E2 envelope and consisted of two separate segments, an N-linker and a β-ribbon connector, and that its bound Fab fragment on E2 overlapped the position that the E3 glycoprotein originally occupied. We showed that CHIKV-E2 is lost during the viral internalization and that CHE19 inhibits the elimination of CHIKV-E2. These findings suggested that CHE19 stabilizes the E2-E1 heterodimer instead of E3 and inhibits the protrusion of the E1 fusion loop and subsequent membrane fusion. In addition, the antigen-bound Fab fragment configuration showed that CHE19 connects to the CHIKV spikes existing on the two individual virions, leading us to conclude that the CHE19-CHIKV complex was responsible for the large virus aggregations. In our subsequent filtration experiments, large viral aggregations by CHE19 were trapped by a 0.45-μm filter. This virion-connecting characteristic of CHE19 could explain the inhibition of viral release from infected cells by the tethering effect of the virion itself. These findings provide clues toward the development of effective prophylactic and therapeutic monoclonal antibodies against the infection. Recent outbreaks of chikungunya fever have increased its clinical importance. Neither a specific antiviral drug nor a commercial vaccine for CHIKV infection are available. Here, we show a detailed model of the docking between the envelope glycoprotein of CHIKV and our unique anti-CHIKV-neutralizing monoclonal antibody (CHE19), which inhibits CHIKV membrane fusion and virion release from CHIKV-infected cells. Homology modeling of the neutralizing antibody CHE19 and protein-protein docking analysis of the CHIKV envelope glycoprotein and CHE19 suggested that CHE19 inhibits the viral membrane fusion by stabilizing the E2-E1 heterodimer and inhibits virion release by facilitating the formation of virus aggregation due to the connecting virions, and these predictions were confirmed by experiments. Sequence information of CHE19 and the CHIKV envelope glycoprotein and their docking model will contribute to future development of an effective prophylactic and therapeutic agent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.00252-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7495367PMC
September 2020

Various miRNAs compensate the role of miR-122 on HCV replication.

PLoS Pathog 2020 06 23;16(6):e1008308. Epub 2020 Jun 23.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.

One of the determinants for tissue tropism of hepatitis C virus (HCV) is miR-122, a liver-specific microRNA. Recently, it has been reported that interaction of miR-122 to HCV RNA induces a conformational change of the 5'UTR internal ribosome entry site (IRES) structure to form stem-loop II structure (SLII) and hijack of translating 80S ribosome through the binding of SLIII to 40S subunit, which leads to efficient translation. On the other hand, low levels of HCV-RNA replication have also been detected in some non-hepatic cells; however, the details of extrahepatic replication remain unknown. These observations suggest the possibility that miRNAs other than miR-122 can support efficient replication of HCV-RNA in non-hepatic cells. Here, we identified a number of such miRNAs and show that they could be divided into two groups: those that bind HCV-RNA at two locations (miR-122 binding sites I and II), in a manner similar to miR-122 (miR-122-like), and those that target a single site that bridges sites I and II and masking both G28 and C29 in the 5'UTR (non-miR-122-like). Although the enhancing activity of these non-hepatic miRNAs were lower than those of miR-122, substantial expression was detected in various normal tissues. Furthermore, structural modeling indicated that both miR-122-like and non-miR-122-like miRNAs not only can facilitate the formation of an HCV IRES SLII but also can stabilize IRES 3D structure in order to facilitate binding of SLIII to the ribosome. Together, these results suggest that HCV facilitates miR-122-independent replication in non-hepatic cells through recruitment of miRNAs other than miR-122. And our findings can provide a more detailed mechanism of miR-122-dependent enhancement of HCV-RNA translation by focusing on IRES tertiary structure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.ppat.1008308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337399PMC
June 2020

Host ESCRT factors are recruited during chikungunya virus infection and are required for the intracellular viral replication cycle.

J Biol Chem 2020 06 27;295(23):7941-7957. Epub 2020 Apr 27.

Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan

Chikungunya fever is a re-emerging zoonotic disease caused by chikungunya virus (CHIKV), a member of the genus in the family. Only a few studies have reported on the host factors required for intracellular CHIKV trafficking. Here, we conducted an imaging-based siRNA screen to identify human host factors for intracellular trafficking that are involved in CHIKV infection, examined their interactions with CHIKV proteins, and investigated the contributions of these proteins to CHIKV infection. The results of the siRNA screen revealed that host endosomal sorting complexes required for transport (ESCRT) proteins are recruited during CHIKV infection. Co-immunoprecipitation analyses revealed that both structural and nonstructural CHIKV proteins interact with hepatocyte growth factor-regulated tyrosine kinase substrate (HGS), a component of the ESCRT-0 complex. We also observed that HGS co-localizes with the E2 protein of CHIKV and with dsRNA, a marker of the replicated CHIKV genome. Results from gene knockdown analyses indicated that, along with other ESCRT factors, HGS facilitates both genome replication and post-translational steps during CHIKV infection. Moreover, we show that ESCRT factors are also required for infections with other alphaviruses. We conclude that during CHIKV infection, several ESCRT factors are recruited via HGS and are involved in viral genome replication and post-translational processing of viral proteins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA119.012303DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7278350PMC
June 2020

Dysregulated Expression of the Nuclear Exosome Targeting Complex Component Rbm7 in Nonhematopoietic Cells Licenses the Development of Fibrosis.

Immunity 2020 03;52(3):542-556.e13

Department of Host Defense, Research Institute for Microbial Diseases (RIMD), Osaka University, Osaka 565-0871, Japan; Laboratory of Host Defense, World Premier Institute Immunology Frontier Research Center (WPI-IFReC), Osaka University, Osaka 565-0871, Japan. Electronic address:

Fibrosis is an incurable disorder of unknown etiology. Segregated-nucleus-containing atypical monocytes (SatMs) are critical for the development of fibrosis. Here we examined the mechanisms that recruit SatMs to pre-fibrotic areas. A screen based on cytokine expression in the fibrotic lung revealed that the chemokine Cxcl12, which is produced by apoptotic nonhematopoietic cells, was essential for SatM recruitment. Analyses of lung tissues at fibrosis onset showed increased expression of Rbm7, a component of the nuclear exosome targeting complex. Rbm7 deletion suppressed bleomycin-induced fibrosis and at a cellular level, suppressed apoptosis of nonhematopoietic cells. Mechanistically, Rbm7 bound to noncoding (nc)RNAs that form subnuclear bodies, including Neat1 speckles. Dysregulated expression of Rbm7 resulted in the nuclear degradation of Neat1 speckles, the dispersion of the DNA repair protein BRCA1, and the triggering of apoptosis. Thus, Rbm7 in epithelial cells plays a critical role in the development of fibrosis by regulating ncRNA decay and thereby the production of chemokines that recruit SatMs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.immuni.2020.02.007DOI Listing
March 2020

Development of a High-Throughput Serum Neutralization Test Using Recombinant Pestiviruses Possessing a Small Reporter Tag.

Pathogens 2020 Mar 4;9(3). Epub 2020 Mar 4.

Laboratory of Microbiology, Division of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan.

A serum neutralization test (SNT) is an essential method for the serological diagnosis of pestivirus infections, including classical swine fever, because of the cross reactivity of antibodies against pestiviruses and the non-quantitative properties of antibodies in an enzyme-linked immunosorbent assay. In conventional SNTs, an immunoperoxidase assay or observation of cytopathic effect after incubation for 3 to 7 days is needed to determine the SNT titer, which requires labor-intensive or time-consuming procedures. Therefore, a new SNT, based on the luciferase system and using classical swine fever virus, bovine viral diarrhea virus, and border disease virus possessing the 11-amino-acid subunit derived from NanoLuc luciferase was developed and evaluated; this approach enabled the rapid and easy determination of the SNT titer using a luminometer. In the new method, SNT titers can be determined tentatively at 2 days post-infection (dpi) and are comparable to those obtained by conventional SNTs at 3 or 4 dpi. In conclusion, the luciferase-based SNT can replace conventional SNTs as a high-throughput antibody test for pestivirus infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/pathogens9030188DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7157198PMC
March 2020

Rimonabant suppresses RNA transcription of hepatitis B virus by inhibiting hepatocyte nuclear factor 4α.

Microbiol Immunol 2020 May 25;64(5):345-355. Epub 2020 Feb 25.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.

Chronic infection with hepatitis B virus (HBV) sometime induces lethal cirrhosis and hepatocellular carcinoma. Although nucleot(s)ide analogs are used as main treatment for HBV infection, the emergence of the drug-resistant viruses has become a problem. To discover novel antivirals with low side effects and low risk of emergence of resistant viruses, screening for anti-HBV compounds was performed with compound libraries of inhibitors targeting G-protein-coupled receptors (GPCRs). HepG2-hNTCP C4 cells infected with HBV were treated with various GPCR inhibitors and harvested at 14 day postinfection for quantification of core protein in the first screening or relaxed circular DNA in the second screening. Finally, we identified a cannabinoid receptor 1 inhibitor, rimonabant, as a candidate showing anti-HBV effect. In HepG2-hNTCP C4 cells, treatment with rimonabant suppressed HBV propagation at the viral RNA transcription step but had no effect on entry or covalently closed circular DNA level. The values of half maximal inhibitory concentration, half maximal effective concentration, and selectivity index of rimonabant in primary human hepatocyte (PHH) are 2.77 μm, 40.4 μm, and 14.6, respectively. Transcriptome analysis of rimonabant-treated primary hepatocytes by RNA sequencing revealed that the transcriptional activity of hepatocyte nuclear factor 4α (HNF4α), which is known to stimulate viral RNA synthesis, was depressed. By treatment of PHH with rimonabant, the expression level of HNF4α protein and the production of the messenger RNAs (mRNAs) of downstream factors promoted by HNF4α were reduced while the amount of HNF4α mRNA was not altered. These results suggest that treatment with rimonabant suppresses HBV propagation through the inhibition of HNF4α activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1348-0421.12777DOI Listing
May 2020

Novel anti-flavivirus drugs targeting the nucleolar distribution of core protein.

Virology 2020 02 29;541:41-51. Epub 2019 Nov 29.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.

The risk of infectious diseases caused by Flavivirus is increasing globally. Here, we developed a novel high-throughput screening (HTS) system to evaluate the inhibitory effects of compounds targeting the nuclear localization of the flavivirus core protein. We screened 4000 compounds based on their ability to inhibit the nuclear localization of the core protein, and identified over 20 compounds including inhibitors for cyclin dependent kinase and glycogen synthase kinase. The efficacy of the identified compounds to suppress viral growth was validated in a cell-based infection system. Remarkably, the nucleolus morphology was affected by the treatment with the compounds, suggesting that the nucleolus function is critical for viral propagation. The present HTS system provides a useful strategy for the identification of antivirals against flavivirus by targeting the nucleolar localization of the core protein.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.virol.2019.11.015DOI Listing
February 2020

Neo-virology: The raison d'etre of viruses.

Virus Res 2019 12 11;274:197751. Epub 2019 Sep 11.

Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan. Electronic address:

Given that approximately 10 virus particles exist on Earth and all of them are parasitic in living organisms, it is not hard to imagine how virus infection might affect the physiology of hosts and their ecosystems. However, traditional virology research tends to focus on viral pathogenicity or the individual pathogenic viruses; hence, the significance of viruses and viral-mediated processes in the global ecosystem has been poorly understood. To identify the previously unrecognized "raison d'etre of viruses" in nature, we established a research community, designated as the 'Neo-virology' consortium. In this consortium, we define a virus as a component of the global ecosystem and our aim is to elucidate its key roles in host organisms, that is, the intra-host ecosystem.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.virusres.2019.197751DOI Listing
December 2019

Dynamics of Reporter Viruses.

J Virol 2019 11 29;93(22). Epub 2019 Oct 29.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan

Recombinant viruses possessing reporter proteins have been generated for virus research. In the case of the family , we recently generated recombinant viruses, including the hepatitis C virus of the genus , Japanese encephalitis virus (JEV) of the genus , and bovine viral diarrhea virus of the genus ; all three viruses possess an 11-amino-acid subunit derived from NanoLuc luciferase (HiBiT). Here, we further developed the recombinant viruses and investigated their utility Recombinant viruses harboring HiBiT in the E, NS1, or NS3 protein constructed based on the predicted secondary structure, solvent-accessible surface area, and root mean square fluctuation of the proteins exhibited comparable replication to that of the wild-type virus The recombinant JEV carrying HiBiT in the NS1 protein exhibited propagation in mice comparable to that of the parental virus, and propagation of the recombinant was monitored by the luciferase activity. In addition, the recombinants of classical swine fever virus (CSFV) possessing HiBiT in the E or E2 protein also showed propagation comparable to that of the wild-type virus. The recombinant CSFV carrying HiBiT in E exhibited similar replication to the parental CSFV in pigs, and detection of viral propagation of this recombinant by luciferase activity was higher than that by quantitative PCR (qPCR). Taken together, these results demonstrated that the reporter viruses generated herein are powerful tools for elucidating the viral life cycle and pathogeneses and provide a robust platform for the development of novel antivirals. applications of reporter viruses are necessary to understand viral pathogenesis and provide a robust platform for antiviral development. In developing such applications, determination of an ideal locus to accommodate foreign genes is important, because insertion of foreign genes into irrelevant loci can disrupt the protein functions required for viral replication. Here, we investigated the criteria to determine ideal insertion sites of foreign genes from the protein structure of viral proteins. The recombinant viruses generated by our criteria exhibited propagation comparable to that of parental viruses Our proteomic approach based on the flexibility profile of viral proteins may provide a useful tool for constructing reporter viruses, including viruses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01191-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6819943PMC
November 2019

Establishment of a Virulent Full-Length cDNA Clone for Type I Feline Coronavirus Strain C3663.

J Virol 2019 11 15;93(21). Epub 2019 Oct 15.

Laboratory of Clinical Research on Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan

Feline infectious peritonitis (FIP) is one of the most important infectious diseases in cats and is caused by feline coronavirus (FCoV). Tissue culture-adapted type I FCoV shows reduced FIP induction in experimental infections, which complicates the understanding of FIP pathogenesis caused by type I FCoV. We previously found that the type I FCoV strain C3663 efficiently induces FIP in specific-pathogen-free cats through the naturally infectious route. In this study, we employed a bacterial artificial chromosome-based reverse genetics system to gain more insights into FIP caused by the C3633 strain. We successfully generated recombinant virus (rC3663) from Fcwf-4 cells transfected with infectious cDNA that showed growth kinetics similar to those shown by the parental virus. Next, we constructed a reporter C3663 virus carrying the nanoluciferase (Nluc) gene to measure viral replication with high sensitivity. The inhibitory effects of different compounds against rC3663-Nluc could be measured within 24 h postinfection. Furthermore, we found that A72 cells derived from canine fibroblasts permitted FCoV replication without apparent cytopathic effects. Thus, our reporter virus is useful for uncovering the infectivity of type I FCoV in different cell lines, including canine-derived cells. Surprisingly, we uncovered aberrant viral RNA transcription of rC3663 in A72 cells. Overall, we succeeded in obtaining infectious cDNA clones derived from type I FCoV that retained its virulence. Our recombinant FCoVs are powerful tools for increasing our understanding of the viral life cycle and pathogenesis of FIP-inducing type I FCoV. Feline coronavirus (FCoV) is one of the most significant coronaviruses, because this virus induces feline infectious peritonitis (FIP), which is a lethal disease in cats. Tissue culture-adapted type I FCoV often loses pathogenicity, which complicates research on type I FCoV-induced feline infectious peritonitis (FIP). Since we previously found that type I FCoV strain C3663 efficiently induces FIP in specific-pathogen-free cats, we established a reverse genetics system for the C3663 strain to obtain recombinant viruses in the present study. By using a reporter C3663 virus, we were able to examine the inhibitory effect of 68 compounds on C3663 replication in Fcwf-4 cells and infectivity in a canine-derived cell line. Interestingly, one canine cell line, A72, permitted FCoV replication but with low efficiency and aberrant viral gene expression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.01208-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6803248PMC
November 2019

Characterization of human pegivirus infection in liver transplantation recipients.

J Med Virol 2019 12 4;91(12):2093-2100. Epub 2019 Aug 4.

Department of Surgery and Science, Graduate School of Medical Sciences, Kyusyu University, Fukuoka, Japan.

Approximately 2% of healthy persons are infected with human pegivirus (HPgV). HPgV is transmitted via vertical, sexual, and blood-borne routes. Recently, the association of HPgV infection with the risk of lymphoma was reported. Here, we examined the prevalence of chronic HPgV infection in liver transplantation (LT) recipients and patients with hepatectomy and the influence of HPgV infection after LT on clinical and perioperative factors. We enrolled 313 LT recipients and 187 patients with hepatectomy who received care at the Kyusyu University Hospital between May 1997 and September 2017. Of the 313 recipients and 187 patients enrolled in this study, 44 recipients (14.1%) and 2 patients (1.1%) had HPgV viremia, respectively. There was no significant association between HPgV infection and LT outcomes. Interestingly, one recipient was infected with HPgV during the peritransplant period, which was likely transmitted via blood transfusion because HPgV RNA was detected from the blood bag transfused to the recipient during LT. We reviewed the available literature on the prevalence HPgV infections in other organ-transplanted patients and whether they impacted clinical outcomes. They also had the higher prevalence of HPgV infection, while it appears to be of low or no consequences. In addition, HPgV infection induced the upregulation of interferon-stimulated gene (ISG) expression in peripheral blood mononuclear cells. LT recipients had higher HPgV viremia compared to patients with hepatectomy. Although HPgV infection was not associated with LT-related outcomes, it induced ISG expression in recipients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jmv.25555DOI Listing
December 2019

Roles of secretory glycoproteins in particle formation of Flaviviridae viruses.

Microbiol Immunol 2019 Oct 19;63(10):401-406. Epub 2019 Aug 19.

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.

The family Flaviviridae comprises four genera, namely, Flavivirus, Pestivirus, Pegivirus, and Hepacivirus. These viruses have similar genome structures, but the genomes of Pestivirus and Flavivirus encode the secretory glycoproteins E and NS1, respectively. E plays an important role in virus particle formation and cell entry, whereas NS1 participates in the formation of replication complexes and virus particles. Conversely, apolipoproteins are known to participate in the formation of infectious particles of hepatitis C virus (HCV) and various secretory glycoproteins play a similar role in HCV particles formation, suggesting that there is no strong specificity for the function of secretory glycoproteins in infectious-particle formation. In addition, recent studies have shown that host-derived apolipoproteins and virus-derived E and NS1 play comparable roles in infectious-particle formation of both HCV and pestiviruses. In this review, we summarize the roles of secretory glycoproteins in the formation of Flaviviridae virus particles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1348-0421.12733DOI Listing
October 2019

CXCR4 regulates development in mouse and human hepatocytes.

J Exp Med 2019 08 12;216(8):1733-1748. Epub 2019 Jun 12.

Department of Immunoparasitology, Osaka University, Osaka, Japan

The liver stage of the etiological agent of malaria, , is obligatory for successful infection of its various mammalian hosts. Differentiation of the rod-shaped sporozoites of into spherical exoerythrocytic forms (EEFs) via bulbous expansion is essential for parasite development in the liver. However, little is known about the host factors regulating the morphological transformation of sporozoites in this organ. Here, we show that sporozoite differentiation into EEFs in the liver involves protein kinase C ζ-mediated NF-κB activation, which robustly induces the expression of C-X-C chemokine receptor type 4 (CXCR4) in hepatocytes and subsequently elevates intracellular Ca levels, thereby triggering sporozoite transformation into EEFs. Blocking CXCR4 expression by genetic or pharmacological intervention profoundly inhibited the liver-stage development of the rodent malaria parasite and the human parasite. Collectively, our experiments show that CXCR4 is a key host factor for development in the liver, and CXCR4 warrants further investigation for malaria prophylaxis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1084/jem.20182227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683982PMC
August 2019