Project description:To further investigate the underlying mechanisms of severe acute respiratory syndrome (SARS) pathogenesis and evaluate the therapeutic efficacy of potential drugs and vaccines it is necessary to use an animal model that is highly representative of the human condition in terms of respiratory anatomy, physiology and clinical sequelae. The ferret, Mustela putorius furo, supports SARS-CoV replication and displays many of the symptoms and pathological features seen in SARS-CoV-infected humans. We have recently established a SARS-CoV infection-challenge ferret platform for use in evaluating potential therapeutics to treat SARS. The main objective of the current study was to extend our previous results and identify early host immune responses upon infection and determine immune correlates of protection upon challenge with SARS-CoV in ferrets. Keywords: time course This study is a simple time course (58 day) examination of host responses in 35 SARS-CoV (TOR2) infected ferrets with the addition of a challenge inoculation of SARS CoV (TOR2) at day 29 post infection. Three mock-infected ferrets are included as negative controls. Due to the unavailability of ferret microarrays, Affymetrix Canine 2.0 oligonucleotide arrays were chosen following sequence analysis of our ferret cDNA library (~5000 clones) and demonstration of high levels of homology (>80%) between dog and ferret.
Project description:Wastewater-based surveillance (WBS) is a proven tool for monitoring population-level infection events. Wastewater contains high concentrations of inhibitors, which contaminate total nucleic acids (TNA) extracted from these samples. We found that TNA extracts from raw influent of Berlin wastewater treatment plants contained highly variable amounts of inhibitors that impaired molecular analyses like dPCR and next-generation sequencing (NGS). By using dilutions, we were able to detect inhibitory effects. To enhance WBS sensitivity and stability, we applied a combination of PCR inhibitor removal and TNA dilution (PIR+D). This approach led to a 26-fold increase in measured SARS-CoV-2 concentrations, practically reducing the detection limit. Additionally, we observed a substantial increase in stability of the time series. We define suitable stability as a mean absolute error (MAE) below 0.1 log10 copies/l and a geometric mean relative absolute error (GMRAE) below 26%. Using PIR+D, the MAE could be reduced from 0.219 to 0.097 and the GMRAE from 65.5% to 26.0% and even further in real-world WBS. Furthermore, PIR+D improved SARS-CoV-2 genome alignment and coverage in amplicon-based NGS for low to medium concentrations. In conclusion, we strongly recommend both the monitoring and removal of inhibitors from samples for WBS.
Project description:A recombinant SARS-CoV lacking the envelope (E) protein is attenuated in vivo. Here we report that E protein PDZ-binding motif (PBM), a domain involved in protein-protein interactions, is a major virulence determinant in vivo. Elimination of SARS-CoV E protein PBM by using reverse genetics led to attenuated viruses (SARS-CoV-mutPBM) and to a reduction in the deleterious exacerbate immune response triggered during infection with the parental virus (SARS-CoV-wt). Cellular protein syntenin bound E protein PBM during SARS-CoV infection. Syntenin activates p38 MAPK leading to overexpression of inflammatory cytokines, and we have shown that active p38 MAPK was reduced in lungs of mice infected with SARS-CoVs lacking E protein PBM (SARS-CoV-mutPBM) as compared with the parental virus (SARS-CoV-wt), leading to a decreased expression of inflammatory cytokines and to viral attenuation. Therefore, E protein PBM is a virulence factor that activates pathogenic immune response most likely by using syntenin as a mediator of p38 MAPK induced inflammation. Three biological replicates were independently hybridized (one channel per slide) for each sample type (SARS-CoV-wt, SARS-CoV-mutPBM, Mock). Slides were Sure Print G3 Agilent 8x60K Mouse (G4852A-028005)
Project description:Severe acute respiratory syndrome virus (SARS-CoV) that lacks the envelope (E) gene (rSARS-CoV-ΔE) is attenuated in vivo [1,2]. To identify factors that contribute to rSARS-CoV-ΔE attenuation, gene expression in cells infected by SARS-CoV with or without E gene was compared. Twenty-five stress response genes were preferentially upregulated during infection in the absence of the E gene. In addition, genes involved in signal transduction, transcription, cell metabolism, immunoregulation, inflammation, apoptosis and cell cycle and differentiation were differentially regulated in cells infected with rSARS-CoV with or without the E gene. Administration of E protein in trans reduced the stress response in cells infected with rSARS-CoV-ΔE, with respiratory syncytial virus, or treated with drugs, such as tunicamycin and thapsigarcin that elicit cell stress by different mechanisms. In addition, SARS-CoV E protein down-regulated the signaling pathway inositol-requiring enzyme 1 (IRE-1) of the unfolded protein response, but not the PKR-like ER kinase (PERK) or activating transcription factor 6 (ATF-6) pathways, and reduced cell apoptosis. Overall, the activation of the IRE-1 pathway was not able to restore cell homeostasis, and apoptosis was induced probably as a meassure to protect the host by limiting virus production and dissemination. The expression of proinflammatory cytokines was reduced in rSARS-CoV-ΔE-infected cells compared to rSARS-CoV-infected cells, suggesting that the increase in stress responses and the reduction of inflammation in the absence of the E gene contributed to the attenuation of rSARS-CoV-ΔE. We used Affymetrix microarrays (Human Genome U133 plus 2.0) to compare global gene expression between SARS-CoV-infected, mock-infected and SARS-CoV-ΔE-infected cells. For ech type of sample three hybridizations were carried-out (independent biological replicates).
Project description:For the assessment of host response dynamics to SARS-CoV and SARS-CoV-2 infections in human airway epithelial cells at ambient temperature corresponding to the upper or lower respiratory tract. We performed a temporal transcriptome analysis on human airway epithelial cell (hAEC) cultures infected with SARS-CoV and SARS-CoV-2, as well as uninfected hAEC cultures, incubated either at 33°C or 37°C. hAEC cultures were harvested at 24, 48 72, 96 hpi and processed for Bulk RNA Barcoding and sequencing (BRB-seq), which allows a rapid and sensitive genome-wide transcriptomic analysis in a highly multiplexed manner. Transcriptome data was obtained from a total of 7 biological donors for pairwise comparisons of SARS-CoV or SARS-CoV-2 virus-infected to unexposed hAEC cultures at respective time points and temperatures.
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease (COVID-19) in humans, which may be lethal. In this study, we used a comparative transcriptomics approach to investigate the effects of SARS-CoV-2 infection on the host mRNA and sRNA expression programs in two primate cell lines. Upon infection, we observed global changes in host gene expression and differential expression of dozens of host miRNAs, many with known links to viral infection and immune response. Unexpectedly, we also discovered an expanded landscape of more than a hundred SARS-CoV-2-derived small viral RNAs (svRNAs), predicted to interact with differentially expressed host mRNAs and miRNAs. svRNAs are derived from distinct regions of the viral genome and sequence signatures suggest they are produced by a non-canonical biogenesis pathway. Our data suggest that svRNAs may play a role in SARS-CoV-2 propagation and antagonization of these svRNAs has potential for use as a therapeutic target.
Project description:A pivotal role of astrocytes in the pathophysiology of CNS disorders during the SARS-CoV-2 infection of brain has been proposed. Thus, the study was performed to reveal astrocyte response to infection caused by either Omicron or Delta variant.