Project description:Enterovirus A71 (EV-A71) receptors that have been identified to date cannot fully explain the pathogenesis of EV-A71, which is an important global cause of hand, foot, and mouth disease and life-threatening encephalitis. We identified an IFN-γ-inducible EV-A71 cellular entry factor, human tryptophanyl-tRNA synthetase (hWARS), using genome-wide RNAi library screening. The importance of hWARS in mediating virus entry and infectivity was confirmed by virus attachment, in vitro pulldown, antibody/antigen blocking, and CRISPR/Cas9-mediated deletion. Hyperexpression and plasma membrane translocation of hWARS were observed in IFN-γ-treated semipermissive (human neuronal NT2) and cDNA-transfected nonpermissive (mouse fibroblast L929) cells, resulting in their sensitization to EV-A71 infection. Our hWARS-transduced mouse infection model showed pathological changes similar to those seen in patients with severe EV-A71 infection. Expression of hWARS is also required for productive infection by other human enteroviruses, including the clinically important coxsackievirus A16 (CV-A16) and EV-D68. This is the first report to our knowledge on the discovery of an entry factor, hWARS, that can be induced by IFN-γ for EV-A71 infection. Given that we detected high levels of IFN-γ in patients with severe EV-A71 infection, our findings extend the knowledge of the pathogenicity of EV-A71 in relation to entry factor expression upon IFN-γ stimulation and the therapeutic options for treating severe EV-A71-associated complications.
Project description:Interferon-γ (IFN-γ) engenders strong antiproliferative responses, in part through activation of p53. However, the long-known IFN-γ-dependent upregulation of human Trp-tRNA synthetase (TrpRS), a cytoplasmic enzyme that activates tryptophan to form Trp-AMP in the first step of protein synthesis, is unexplained. Here we report a nuclear complex of TrpRS with the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) and with poly(ADP-ribose) polymerase 1 (PARP-1), the major PARP in human cells. The IFN-γ-dependent poly(ADP-ribosyl)ation of DNA-PKcs (which activates its kinase function) and concomitant activation of the tumor suppressor p53 were specifically prevented by Trp-SA, an analog of Trp-AMP that disrupted the TrpRS-DNA-PKcs-PARP-1 complex. The connection of TrpRS to p53 signaling in vivo was confirmed in a vertebrate system. These and further results suggest an unexpected evolutionary expansion of the protein synthesis apparatus to a nuclear role that links major signaling pathways.
Project description:This study finds that EV71 has oncolytic activity against experimental human malignant gliomas. RNA-seq analysis of infected glioma cells reveals transcriptional up-regulation, notably genes in apoptosis pathways. Application of virus targeting based on brain-specific microRNA-124 enhances the safety profile. Oncolysis with EV71 may be a potentially novel treatment for malignant gliomas.
Project description:We have previously shown that Heparin (Hep) significantly inhibited Enterovirus 71 (EV71) infection and binding in both Vero and a human neural cell line, SK-N-SH, in vitro. Therefore, in this study we intended to gain insight into the cellular and molecular mechanisms of action of Hep against clinical EV71 infection in SK-N-SH cells. Instead of stating a long list of gene functions and pathways, we tried to select for EV71-induced genes that were exclusively affected by antiviral activity of Hep through a multi-level comparison and characterization. Overall, our microarray analysis may suggest that Hep might exert its anti-EV71 activity in SK-N-SH cells, at least in part, through the following mechanisms: i. Reduction of the down-regulation effect of EV71 on TOX that would lead to an increased population of effective, mature T-cells and NK-cells; ii. Reduction of the up-regulation effect of EV71 on GIP, that in turn, would reduce recruiting different GPCRs, leading to a reduced viral infection in host cells; iii. Partially neutralization of the EV71-mediated apoptosis through expression of CARP2 that acts as an anti-apoptosis ubiquitin protein ligase (E3). EV71 is a neurovirological virus that can sometimes cause severe and fatal CNS complications in infected patients. Since still there is no approved drug for prophylaxis of EV71-casued disease, discovering a molecular drug target(s) for EV71 infection would be crucial. This was the first study to report direct assessment of mechanisms of action of antivirals against EV71 infection. SK-N-SH cells were infected with a clinical EV71 isolate followed by treatment with 125 µg/mL of Hep. At 72 hours post infection, antiviral activity and cytotoxicity of Hep at 125 µg/mL in 12-well plates were carried out at the same time as RNA extraction. This way, we could ensure that we would assess transcript profiles of the host cells under the same condition and time as assessment of antiviral activity and cytotoxicity for the same replicates. Changes in expression profiles of the host cells were comparatively assessed under four conditions: cell control (neither infection nor treatment, designated CC), treated only with Hep (compound control, designated Cyto), EV71-infected cells treated with Hep (treatment, designated H), and infected with EV71 without treatment with Hep (virus control, designated V). All experiments were applied in triplicate, and totally twelve GeneChip® Human Gene 1.0 ST arrays were purchased from Affymetrix and processed. Then, the following five contrasts were made: Hep vs. CC; VC vs. CC; Cyto vs CC; Hep vs. VC; and Hep vs. Cyto. For each contrast, only samples from the two target groups were included. The statistical parameters of ANOVAs, p values, multiple test corrections, and fold changes were calculated within each contrast. Then, a multi-level selection and analysis procedure was employed in order to attribute changes in the gene transcription level to antiviral activity of Hep.
Project description:Enterovirus 71 (EV71) belongs to human enterovirus species A of the genus Enterovirus within the family Picornaviridae. We established transformant cells by transfection of mouse cells with genomic DNA from human cells and then detected two EV71-susceptible cell lines. Using microarray with the two cell lines we found that scavenger receptor B2 is a cellular receptor for EV71.
Project description:We have previously shown that Heparin (Hep) significantly inhibited Enterovirus 71 (EV71) infection and binding in both Vero and a human neural cell line, SK-N-SH, in vitro. Therefore, in this study we intended to gain insight into the cellular and molecular mechanisms of action of Hep against clinical EV71 infection in neural cells. Instead of stating a long list of gene functions and pathways, we tried to select for EV71-induced genes that were exclusively affected by antiviral activity of Hep through a multi-level comparison and characterization. Overall, the findings of this study suggest several molecular targets by which Hep might exert its antiviral activity against clinical EV71 infection in neural cells. Mostly, Hep appeared to modulate induction effect of EV71 on several genes in a way that may benefit the host cell and inhibit the viral infection. The most important genes where expression patterns were significantly changed by Hep include genes related to; (i) cell growth, (ii) DNA repair and replication, (iii) cytoplasmic microfilaments and related apoptosis, (iv) regulation of energy metabolism and mitochondrion-related apoptosis, (v) cytoplasmic viral transport, (vi) transmembrane proteins and the related signaling pathways, (vii) phosphoribosyltransferase, (viii) transcription factors, (ix) G protein-coupled receptors and G protein-coupled receptors-interacting proteins, (x) remodeling actin filament assembly, (xi) chemokin receptors, and (xii) immunosuppression. In addition, Hep sometimes appeared to be harmful for cells, like the case in that Hep likely suppresses regulation of Metallothionein 1E. Furthermore, it should not be ignored that the Hep-caused affects seen in this microarray analysis may partially be attributed to a significant inhibitory effect of Hep on EV71 entry into the cells. In conclusion, we propose that our microarray findings may suggest new directions for further studies on molecular targets of anti-EV71 activity of Hep. EV71 is a neurovirological virus that can cause severe and fatal CNS complications in infected patients. There is no approved drug for prophylaxis of EV71-casued disease and discovering a molecular drug target(s) for EV71 infection would be beneficial. The microarray analysis reported here was a large-scale microarray pilot study and thus further confirmatory experiments such as real time RT PCR and Western blotting would be warranted in order to confirm the mode of action of Hep implied here.
Project description:Hand, foot and mouth disease (HFMD), caused by enterovirus 71 (EV71), presents mild to severe disease, and sometimes fatal neurological and respiratory manifestations. However, reasons for the severe pathogenesis remain undefined. To investigate this, infection and viral kinetics of EV71 isolates from clinical disease (mild, moderate and severe) from Sarawak, Malaysia, were characterized in human rhabdomyosarcoma (RD), neuroblastoma (SH-SY5Y) and peripheral blood mononuclear cells (PBMCs). High resolution transcriptomics was used to decipher EV71-host interactions in PBMCs. Ingenuity analyses revealed similar pathways triggered by all EV71 isolates, although the extent of activation varied. Importantly, several pathways were found to be specific to the severe isolate, including triggering receptor expressed on myeloid cells 1 (TREM-1) signaling. Depletion of TREM-1 in EV71-infected PBMCs with peptide LP17 resulted in decreased levels of pro-inflammatory genes, and reduced viral loads for the moderate and severe isolates. Mechanistically, this is the first report describing the transcriptome profiles during EV71 infections in primary human cells, and the involvement of TREM-1 in the severe disease pathogenesis, thus providing new insights for future treatment targets.
Project description:Enterovirus 71 (EV71) causes Hand, Foot, and Mouth Disease and has been clinically associated with neurological complications. However, there is a lack of relevant models to elucidate the neuropathology of EV71 and its mechanism, as the current models mainly utilize animal model or immortalized cell lines. In this study, we established a human motor neuron model for EV71 infection.
Project description:Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are major causative agents for hand, foot and mouth disease (HFMD). In China, more than 70,756 children were infected and 40 died from the disease in recent years. This study aimed to develop a protein chip that can simultaneously detect and differentiate the antibodies induced by EV71 and CA16 simultaneously. The structure protein vp1 and vp3 from the two viruses were purified and spotted onto an aldehyde groupmodified glass slide at 1mg/ml. After that, the protein chip was reacted with the corresponding positive serum against these viruses, hybridized with a Cy3-labeled secondary antibody and scanned using the popular GenePix 4000B Microarray Scanner. In this study, Both IgG and IgM serum antibody to EV71 and CA16 were detected using protein Chip. The results showed that this method could hybridize specifically with the corresponding antibodies with strong signals and without cross-hybridization. The data also confirmed the proposed method's specificity, sensitivity, and convenience. In conclusion, this protein chip can be used to differentiate the antibodies induced by the EV71and CA16.
Project description:Enterovirus 71 (EV71) infection causes a profound shutoff of cellular protein synthesis. Deep RNA-sequencing and ribosome profiling were employed to systematically analyze messenger RNA and ribosome-protected RNA in EV71-infected rhabdomyosarcoma cells at progressive time points following infection. The analysis characterized the dynamic transcriptional and translational landscapes of both the virus and host cells. The results indicated that reduced translation of cellular mRNAs played a key role in EV71-induced host shutoff rather than mRNA depletion. During the host shutoff, EV71 protein was preferably synthesized through both a translational advantage and abundant mRNA production. Moreover, a small number of cellular genes were resistant to the host shutoff through both transcriptional and translational regulation, including genes in mitogen-activated protein kinase (MAPK) signaling pathway that is important for EV71 replication. These results indicated selective cellular protein synthesis during EV71-induced host shutoff as a mechanism the virus utilizes to benefit its replication.