scholarly journals Porcine epidemic diarrhea virus (PEDV) co-infection induced chlamydial persistence/stress does not require viral replication

Author(s):  
Robert V. Schoborg ◽  
Nicole Borel
Viruses ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 127 ◽  
Author(s):  
Zhonghua Li ◽  
Wei Zeng ◽  
Shiyi Ye ◽  
Jian Lv ◽  
Axiu Nie ◽  
...  

2021 ◽  
Author(s):  
Liumei Sun ◽  
Huan Chen ◽  
Xin Ming ◽  
Zongyi Bo ◽  
Hyun-Jin Shin ◽  
...  

Porcine Epidemic Diarrhea Virus (PEDV) is an α-coronavirus causing severe diarrhea and high mortality rates in suckling piglets and posing significant economic impact. PEDV replication is completed and results in a large amount of RNA in the cytoplasm. Stress granules (SGs) are dynamic cytosolic RNA granules formed under various stress conditions including viral infections. Several previous studies suggested that SGs were involved in the antiviral activity of host cells to limit viral propagation. However, the underlying mechanisms are poorly understood. This study aimed to delineate the molecular mechanisms regulating the SG response to PEDV infection. SG formation is induced early during PEDV infection, but as infection proceeds, this ability is lost and SGs disappear at late stages of infection (>18 hours post-infection). PEDV infection resulted in the cleavage of Ras-GTPase-activating protein-binding protein 1 (G3BP1) mediated by caspase-8. Using mutational analysis, the PEDV-induced cleavage site within G3BP1 was identified, which differed from the 3C protease cleavage site previously identified. Furthermore, G3BP1 cleavage by caspase-8 at D168 and D169 was confirmed in vitro as well as in vivo. The overexpression of cleavage-resistant G3BP1 conferred persistent SG formation and suppression of viral replication. Additionally, the knockdown of endogenous G3BP1 abolished SG formation and potentiated viral replication. Taken together, these data provide new insights into novel strategies in which PEDV limits the host stress response and antiviral responses, and indicate that caspase-8-mediated G3BP1 cleavage is important in the failure of host defense against PEDV infection. Importance: Coronaviruses (CoVs) are drawing extensive attention again since the outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019. CoVs are prone to variation and own the transmission capability by crossing the species barrier resulting in reemergence. How CoVs manipulate the antiviral responses of their hosts needs to be explored. Overall, the study provides new insight into how Porcine Epidemic Diarrhea Virus (PEDV) impaired SG assembly by targeting G3BP1 via the host proteinase caspase-8. These findings enhanced the understanding of PEDV infection and might help identify new antiviral targets that could inhibit viral replication and limit the pathogenesis of PEDV.


2020 ◽  
Vol 94 (16) ◽  
Author(s):  
Yunjian Lu ◽  
Hui Cai ◽  
Mijia Lu ◽  
Yuanmei Ma ◽  
Anzhong Li ◽  
...  

ABSTRACT The 5′ cap methylation of viral RNA plays important roles in RNA stability, efficient translation, and immune evasion. Thus, RNA cap methylation is an attractive target for antiviral discovery and development of new live attenuated vaccines. For coronaviruses, RNA cap structure is first methylated at the guanine-N-7 (G-N-7) position by nonstructural protein 14 (nsp14), which facilitates and precedes the subsequent ribose 2′-O methylation by the nsp16-nsp10 complex. Using porcine epidemic diarrhea virus (PEDV), an Alphacoronavirus, as a model, we showed that G-N-7 methyltransferase (G-N-7 MTase) of PEDV nsp14 methylated RNA substrates in a sequence-unspecific manner. PEDV nsp14 can efficiently methylate RNA substrates with various lengths in both neutral and alkaline pH environments and can methylate cap analogs (GpppA and GpppG) and single-nucleotide GTP but not ATP, CTP, or UTP. Mutations to the S-adenosyl-l-methionine (SAM) binding motif in the nsp14 abolished the G-N-7 MTase activity and were lethal to PEDV. However, recombinant rPEDV-D350A with a single mutation (D350A) in nsp14, which retained 29.0% of G-N-7 MTase activity, was viable. Recombinant rPEDV-D350A formed a significantly smaller plaque and had significant defects in viral protein synthesis and viral replication in Vero CCL-81 cells and intestinal porcine epithelial cells (IPEC-DQ). Notably, rPEDV-D350A induced significantly higher expression of both type I and III interferons in IPEC-DQ cells than the parental rPEDV. Collectively, our results demonstrate that G-N-7 MTase activity of PEDV modulates viral replication, gene expression, and innate immune responses. IMPORTANCE Coronaviruses (CoVs) include a wide range of important human and animal pathogens. Examples of human CoVs include severe acute respiratory syndrome coronavirus (SARS-CoV-1), Middle East respiratory syndrome coronavirus (MERS-CoV), and the most recently emerged SARS-CoV-2. Examples of pig CoVs include porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine enteric alphacoronavirus (SeACoV). There are no vaccines or antiviral drugs for most of these viruses. All known CoVs encode a bifunctional nsp14 protein which possesses ExoN and guanine-N-7 methyltransferase (G-N-7 MTase) activities, responsible for replication fidelity and RNA cap G-N-7 methylation, respectively. Here, we biochemically characterized G-N-7 MTase of PEDV nsp14 and found that G-N-7 MTase-deficient PEDV was defective in replication and induced greater responses of type I and III interferons. These findings highlight that CoV G-N-7 MTase may be a novel target for rational design of live attenuated vaccines and antiviral drugs.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gustavo Machado ◽  
Carles Vilalta ◽  
Mariana Recamonde-Mendoza ◽  
Cesar Corzo ◽  
Montserrat Torremorell ◽  
...  

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 216-217
Author(s):  
O L Harrison ◽  
G E Nichols ◽  
J T Gebhardt ◽  
Cassandra K Jones ◽  
Jason C Woodworth ◽  
...  

Abstract Recent research has demonstrated that swine viruses can be transmitted via feed. Chemical feed additives have been suggested for the mitigation of these viruses in complete feed. Therefore, the objective of this study was to evaluate the efficacy of a commercially available formaldehyde-based feed additive, medium chain fatty acid blend (MCFA), and commercially available fatty acid-based products for mitigation of porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV) in a feed matrix. Treatments consisted of: 1) non-treated positive control, 2) 0.33% commercial formaldehyde-based product (Sal Curb; Kemin Industries, Inc.; Des Moines, IA), 3) 0.5% MCFA blend (1:1:1 ratio of C6:0, C8:0, and C10:0, Sigma Aldrich, St. Louis, MO), 4) 0.25%, 5) 0.5%, or 6) 1% of commercial dry mono and diglyceride-based product (Furst Strike; Furst-McNess Company, Freeport, IL), 7) 0.25%, 8) 0.5%, or 9) 1% of commercial dry mono and diglyceride-based product (Furst Protect; Furst-McNess Company, Freeport, IL), 10) 0.25%, 11) 0.5%, or 12) 1% dry mono and diglyceride-based experimental product (Furst-McNess Company, Freeport, IL) with 3 replications/treatment. Treatments were applied to complete swine feed before inoculation with 106 TCID50/g of feed with PEDV or PRRSV. Post inoculation feed was held at ambient temperature for 24 h before being analyzed via qRT-PCR. The analyzed values represent the cycle threshold. Formaldehyde and MCFA decreased (P < 0.05) the detectable RNA of PEDV and PRRSV compared to all other treatments. Furst Strike, Furst Protect, and the experimental product did not significantly impact detectability of PEDV or PRRSV RNA. In conclusion, MCFA and formaldehyde treatments are effective at reducing detection of RNA from PEDV and PRRSV in feed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaoqian Zhang ◽  
Chang Li ◽  
Bingzhou Zhang ◽  
Zhonghua Li ◽  
Wei Zeng ◽  
...  

AbstractThe variant virulent porcine epidemic diarrhea virus (PEDV) strain (YN15) can cause severe porcine epidemic diarrhea (PED); however, the attenuated vaccine-like PEDV strain (YN144) can induce immunity in piglets. To investigate the differences in pathogenesis and epigenetic mechanisms between the two strains, differential expression and correlation analyses of the microRNA (miRNA) and mRNA in swine testicular (ST) cells infected with YN15, YN144, and mock were performed on three comparison groups (YN15 vs Control, YN144 vs Control, and YN15 vs YN144). The mRNA and miRNA expression profiles were obtained using next-generation sequencing (NGS), and the differentially expressed (DE) (p-value < 0.05) mRNA and miRNA were obtained using DESeq R package. mRNAs targeted by DE miRNAs were predicted using the miRanda algortithm. 8039, 8631 and 3310 DE mRNAs, and 36, 36, and 22 DE miRNAs were identified in the three comparison groups, respectively. 14,140, 15,367 and 3771 DE miRNA–mRNA (targeted by DE miRNAs) interaction pairs with negatively correlated expression patterns were identified, and interaction networks were constructed using Cytoscape. Six DE miRNAs and six DE mRNAs were randomly selected to verify the sequencing data by real-time relative quantitative reverse transcription polymerase chain reaction (qRT-PCR). Based on bioinformatics analysis, we discovered the differences were mostly involved in host immune responses and viral pathogenicity, including NF-κB signaling pathway and bacterial invasion of epithelial cells, etc. This is the first comprehensive comparison of DE miRNA–mRNA pairs in YN15 and YN144 infection in vitro, which could provide novel strategies for the prevention and control of PED.


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