Project description:Severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) are zoonotic pathogens that can cause severe respiratory disease in humans. Identification of the host factors that are necessary for viral infection and virus-induced cell death is critical to our understanding of the viral life cycle and can potentially aid the development of new treatment options. Here, we report CRISPR screen results of both SARS-CoV and MERS-CoV infections in derivatives of the human hepatoma cell line Huh7. Our screens identified the known entry receptors ACE2 for SARS-CoV and DPP4 for MERS-CoV. Additionally, the SARS-CoV screen uncovered several components of the NF-κB signaling pathway (CARD10, BCL10, MALT1, MAP3K7, IKBKG), while the MERS-CoV screen revealed the polypyrimidine tract-binding protein PTBP1, the ER scramblase TMEM41B, furin protease and several transcriptional and chromatin regulators as candidate factors for viral replication and/or virus-induced cell death. Together, we present several known and unknown coronavirus host factors that are of interest for further investigation.
Project description:Background: The recent emergence of a novel coronavirus in the Middle East (designated MERS-CoV) is a reminder of the zoonotic potential of coronaviruses and the severe disease these etiologic agents can cause in humans. Clinical features of Middle East respiratory syndrome (MERS) include severe acute pneumonia and renal failure that is highly reminiscent of severe acute respiratory syndrome (SARS) caused by SARS-CoV. The host response is a key component of highly pathogenic respiratory virus infection. Here, we computationally analyzed gene expression changes in a human airway epithelial cell line infected with two genetically distinct MERS-CoV strains obtained from human patients, MERS-CoV-EMC (designated EMC) and MERS-CoV-London (designated LoCoV). Results: Using topological techniques, such as persistence homology and filtered clustering, we characterized the host response system to the different MERS-CoVs, with LoCoV inducing early kinetic changes, between 3 and 12 hours post infection, compared to EMC. Robust transcriptional changes distinguished the two MERS-CoV strains predominantly at the late time points. Combining statistical analysis of infection and cytokine-stimulated treatment transcriptomics, we identified differential innate and pro-inflammatory responses between the two virus strains, including up-regulation of extracellular remodeling genes following LoCoV infection and differential pro-inflammatory responses between the two strains. Conclusions: These transcriptional differences may be the result of amino acid differences in viral proteins known to modulate innate immunity against MERS infection. Triplicate wells of Calu-3 2B4 cells were infected with Human Coronavirus EMC 2012 (HCoV-EMC) or time-matched mock infected. Cells were harvested at 0, 3, 7, 12, 18 and 24 hours post-infection (hpi), RNA extracted and transcriptomics analyzed by microarray.
Project description:Human circular RNAs can function in competing endogenous RNA (ceRNA) network by sponging miRNA and regulating gene expression. Viruses are evolved to regulate noncoding RNAs such as miRNAs and circRNAs to facilitate their propagation and pathogenesis. Studies on how host ceRNAs upon human coronavirus infection were scarce, and the functions of circRNAs during the infection of Middle East respiratory syndrome coronavirus (MERS-CoV) has not been deeply revealed. Therefore, we conducted a whole transcriptional profile (RNA-seq) analysis to compare the expression of circRNAs, miRNAs and mRNAs between the mock-infected and MERS-CoV-infected human lung adenocarcinoma (Calu-3) cells. Integrated analysis of ceRNAs revealed putative viral pathogenic circRNAs induced by MERS-CoV and their interplay with miRNAs and genes. Our study offered new insights into the mechanisms of interplays of MERS-CoVs and hosts, and established a model promising to be applied to other coronavirus or other viruses for the identification of novel host factors.
Project description:COVID-19 is the third outbreak of zoonotic coronavirus (CoV) of the century after the epidemic Severe acute respiratory syndrome CoV (SARS-CoV) in 2003 and Middle East respiratory syndrome CoV (MERS-CoV) in 2012. Treatment options for CoVs are largely lacking. Here, we show that clofazimine, an anti-leprosy drug with favorable safety and pharmacokinetics profile, possesses pan-coronaviral inhibitory activity, and can antagonize SARS-CoV-2 replication in multiple in vitro systems, including the human embryonic stem cell-derived cardiomyocytes and ex vivo lung cultures. The FDA-approved molecule was found to inhibit multiple steps of viral replication, suggesting polypharmacology is likely underlying its antiviral activity. In a hamster model of SARS-CoV-2 pathogenesis, prophylactic and therapeutic administration of clofazimine significantly reduced lung viral load and fecal viral shedding, as well as reversal of cytokine storm. Additionally, clofazimine exhibited antiviral drug synergy when administered with remdesivir. Since clofazimine is orally bioavailable and has a comparatively low manufacturing cost, it is an attractive clinical candidate for outpatient treatment and remdesivir-based combinatorial therapy for hospitalized COVID-19 patients, particularly in developing countries. Taken together, our data provide evidence that clofazimine may prove effective against current pandemic SARS-CoV-2, endemic MERS-CoV in the Middle East, and, possibly most importantly, emerging CoV of the future.
Project description:We will use the EMC/2012 strain of the novel beta Coronavirus called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). It was initially passaged on Vero E6 cells in Saudi Arabia before being sequenced at the Erasmus Medical College in Rotterdam, Netherlands by Dr Ron Fouchier. We propose to perform a time course of infection of hCoV-EMC on MRC5 cells (Human Lung origin) and Vero cells (African Green Monkey Kidney cells). Both cell lines readily grow and replicate the virus. Importantly these cell lines show signs of Cytopathic effect (CPE), such as cell rounding and release from the petri dish that coincide with time points high virus replication demonstrating the effects of virus replication on the cells. Transcriptomic analysis will be performed after infection with MERS-CoV and SARS-CoV (Urbani strain) to compare the host gene induction that occurs during infection. MRC5 and Vero E6 cells will be infected at an MOI of 0.1 and 3 and RNA harvested from cells at 24 and 48 post infection. RNA will be processed for library creation and sequenced on an Illumina Hiseq. Sequencing reads will be analyzed and compared across the time course and between each virus to identify common response pathways induced during infection as well as unique pathways specific to each virus.
Project description:We will use the EMC/2012 strain of the novel beta Coronavirus called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). It was initially passaged on Vero E6 cells in Saudi Arabia before being sequenced at the Erasmus Medical College in Rotterdam, Netherlands by Dr Ron Fouchier. We propose to perform a time course of infection of hCoV-EMC on MRC5 cells (Human Lung origin) and Vero cells (African Green Monkey Kidney cells). Both cell lines readily grow and replicate the virus. Importantly these cell lines show signs of Cytopathic effect (CPE), such as cell rounding and release from the petri dish that coincide with time points high virus replication demonstrating the effects of virus replication on the cells. Transcriptomic analysis will be performed after infection with MERS-CoV and SARS-CoV (Urbani strain) to compare the host gene induction that occurs during infection.
Project description:We will use the EMC/2012 strain of the novel beta Coronavirus called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). It was initially passaged on Vero E6 cells in Saudi Arabia before being sequenced at the Erasmus Medical College in Rotterdam, Netherlands by Dr Ron Fouchier. We propose to perform a time course of infection of hCoV-EMC on MRC5 cells (Human Lung origin) and Vero cells (African Green Monkey Kidney cells). Both cell lines readily grow and replicate the virus. Importantly these cell lines show signs of Cytopathic effect (CPE), such as cell rounding and release from the petri dish that coincide with time points high virus replication demonstrating the effects of virus replication on the cells. Transcriptomic analysis will be performed after infection with MERS-CoV and SARS-CoV (Urbani strain) to compare the host gene induction that occurs during infection.
Project description:The absence of a robust disease model currently hinders the evaluation of countermeasures for Middle East respiratory syndrome coronavirus (MERS-CoV). While a rhesus macaque model of MERS-CoV that results in mild-to-moderate disease has been utilized to describe the pathogenesis of this virus and for the evaluation of therapeutics, the inability to produce uniform disease with substantial virus replication complicates analysis in countermeasure studies. In an attempt to identify a more robust disease model, DPP4 sequences of various non-human primates were aligned. Modeling of the interactions between the receptor binding domain of MERS-CoV and its cognate receptor DPP4 predicted a "good fit" with complete conservation of all of the critical residues. To determine the feasibility of the marmoset as a MERS-CoV disease model, common marmosets were inoculated with MERS-CoV via combined intratracheal, intranasal, oral and ocular routes. Marmosets developed signs of moderate to severe illness with progressive serious to severe pneumonia. Progressive gross lesions were evident in animals necropsied at 3, 4 and 6 days post inoculation and two animals were euthanized during the study due to disease severity. This is the first description of a moderate-to-severe, with potentially lethality, disease model of MERS-CoV and as such will have utility for vaccine and other countermeasure efficacy evaluations in addition to further pathogenesis studies. Lung tissue samples were isolated and sequenced at 3, 4 and 6 days post inoculation. Two animals were euthanized during the study due to disease severity.
Project description:Middle East respiratory syndrome coronavirus (MERS-CoV) is a beta coronavirus that emerged in 2012, causing severe pneumonia and renal failure. MERS-CoV encodes five accessory proteins. Some of them have been shown to interfere with host antiviral immune response. However, the roles of protein 8b in innate immunity and viral virulence was rarely studied. Here, we introduced individual MERS-CoV accessory protein genes into the genome of an attenuated murine coronavirus (Mouse hepatitis virus, MHV), respectively and found accessory protein 8b could enhance viral replication in vivo and in vitro, and increase the lethality of infected mice. RNA-seq analysis revealed that protein 8b could significantly inhibit type I interferon production (IFN-I) and innate immune response in mice infected with MHV expressing protein 8b. We also found that MERS-CoV protein 8b could initiate from multiple internal methionine sites and at least three protein variants were identified. Residues 1-23 of protein 8b was demonstrated to be responsible for increased virulence in vivo. In addition, the inhibitory effect on IFN-I of protein 8b might not contribute to its virulence enhancement as aa1-23 deletion did not affect IFN-I production in vitro and in vivo. Next, we also found that protein 8b was localized to the endoplasmic reticulum (ER)/Golgi membrane in infected cells, which was disrupted by C-terminal region aa 88-112 deletion. This study will provide new insight into the pathogenesis of MERS-CoV infection.