Alarmin S100A8/A9 mediates activation of aberrant neutrophils in the pathogenesis of COVID-19
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ABSTRACT: To characterize the early immune responses against coronavirus infection, we infected rhesus macaques and hACE2 transgenic mice with SARS-CoV-2 and analyzed the transcriptome of infected and non-infected animals. We infected WT mice with IAV as a normal respiratory virus group. During analysis, we found that S100A8 was dramatically upregulated by SARS-CoV-2 and a mouse coronavirus (mouse hepatitis virus, MHV), but not by other tested viruses. A group of non-canonical neutrophils were also activated during SARS-CoV-2 infection.
Project description:Rhinoviruses (RV) have been shown to inhibit subsequent infection by heterologous respiratory viruses, including influenza viruses and severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). To better understand the mechanisms whereby RV protects against pulmonary coronavirus infection, we used a native murine virus, mouse hepatitis virus strain 1 (MHV-1), that causes severe disease in the lungs of infected mice. We found that priming of the respiratory tract with RV completely prevented mortality and reduced morbidity of a lethal MHV-1 infection. Replication of MHV-1 was reduced in RV-primed mouse lungs although type I interferon (IFN-b) expression was more robust in mice infected with MHV-1 alone. We further showed that type I IFN signaling was required for survival of mice given a non-lethal dose of MHV-1. RV-primed mice had reduced pulmonary inflammation and hemorrhage and influx of leukocytes, especially neutrophils, in the airways. RV-mediated priming in the respiratory tract protects against a lethal pulmonary coronavirus infection in mice. This model can be used to understand how heterologous viruses impact each other during coinfection of the respiratory tract.
Project description:Coronavirus disease 2019 (COVID-19), caused by infection with the enveloped RNA betacoronavirus, SARS-CoV-2, led to a global pandemic involving over 7 million deaths. Macrophage inflammatory responses impact COVID-19 severity; however, it is unclear whether macrophages are infected by SARS-CoV-2. We sought to identify mechanisms regulating macrophage expression of ACE2, the primary receptor for SARS-CoV-2, and to determine if macrophages are susceptible to productive infection. We developed a humanized ACE2 (hACE2) mouse whereby hACE2 cDNA was cloned into the mouse ACE2 locus under control of the native promoter. We validated susceptibility of hACE2 mice to SARS-CoV-2 infection relative to wild-type mice or an established K18-hACE2 model of acute fulminating disease. Intranasal exposure to SARS-CoV-2 led to pulmonary consolidations with cellular infiltrate, edema, and hemorrhage, consistent with pneumonia, yet unlike the K18-hACE2 model, hACE2 mice survived and maintained stable weight. Infected hACE2 mice also exhibited a unique plasma chemokine, cytokine, and growth factor, inflammatory signature relative to K18-hACE2 mice. Infected hACE2 mice demonstrated evidence of viral replication in infiltrating lung macrophages, and infection of macrophages in vitro revealed a transcriptional profile indicative of altered RNA and ribosomal processing machinery as well as activated cellular antiviral defense. Macrophage IL-1β-driven NF-B transcription of ACE2 appeared to be an important mechanism of dynamic ACE2 upregulation, promoting macrophage susceptibility to infection. Experimental models of COVID-19 that make use of native hACE2 expression will allow for mechanistic insight into factors that can either promote host resilience or increase susceptibility to worsening severity of infection.
Project description:Differential expression was determined in Calu-3 cells between mock infected and infection with either Human coronavirus EMC and SARS coronavirus at different times post infection. Calu-3 2B4 cells were infected with Human Coronavirus EMC 2012 (HCoV-EMC) or mock infected. Samples were collected 0, 3, 7, 12, 18 and 24 hpi. There are 3 mock and 3 infected replicates for each time point, except for 12 hpi for which there are only 2 infected replicates (one replicate did not pass RNA quality check). There were no mock sampes at 18 hpi, and therefore infected samples at 18 hpi were compared with mocks at 24 hpi. For direct comparison with SARS-CoV infected cells, raw data from HCoV-EMC experiments were quantile normalized together with the SARS-CoV dataset (GEO Series accession number GSE33267).
Project description:hACE2 transgenic mice were infected with the original SARS-CoV-2 strain (B.1) and the Beta (B.1.351) variant. Lung and spleen samples were collected 1 day post infection (DPI), 3 DPI and 5 DPI, and mRNA was sequenced.
Project description:In our study, we found that SARS-CoV-2-S pseudovirions infection induced high levels of autophagy and apoptosis in infected cells. To further investigate the underlying regualtion of SARS-CoV-2-S pseudovirions infection in infected cells, ACE2-expressing HEK293T-hACE2 and Vero E6 cells were treated with Mock or SARS-CoV-2-S pseudovirions for RNA-Seq analysis to exame the expression of autophagy- and apoptosis-related genes. Our results indicate that the majority of autophagy- and apoptosis-promoting genes were significantly increased in SARS-CoV-2-S pseudovirions treated HEK293T-hACE2 and Vero E6 cells. In contrast, the subset of autophagy- and apoptosis-suppressing genes was significantly decreased in SARS-CoV-2-S pseudovirions-treated HEK293T-hACE2 and Vero E6 cells than Mock-treated HEK293T-hACE2 and Vero E6 cells. Meanwhile, SARS-CoV-2-S pseudovirions infection enhanced the expression of pro-inflammatory cytokines in infected cells.
Project description:We demonstrate that the histone demethylase KDM6A promotes infection of diverse coronaviruses, including SARS-CoV-1, SARS-CoV-2, MERS-CoV and mouse hepatitis virus (MHV) in a demethylase activity-independent manner
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of individuals worldwide, causing a severe global pandemic. Mice models are wildly used to investigate viral infection pathology, antiviral drugs, and vaccine development. However, since wild-type mice do not express human angiotensin-converting enzyme 2 (hACE2), which mediates SARS-CoV-2 entry into human cells, they are not susceptible to infection with SARS-CoV-2 and are not suitable to simulate symptomatic COVID-19 disease. HACE2 transgenic mice could provide an efficient model, but they are expensive, not always readily available and practically restricted to specific strain(s). Since additional models are needed to study the disease at varying genetic and immune backgrounds, there is a dearth of mouse models for SARS-CoV-2 infection. Here we report the application of lentiviral vectors to generate hACE2 expression in mouse lung epithelial cells (LET1) as well as in interferon receptor knock-out (IFNAR1-/-) mice. Lenti-hACE2 transduction supported SARS-CoV-2 replication both in vitro and in vivo, simulating mild acute lung disease1. Gene expression analysis revealed two modes of immune responses to SARS-CoV-2 infection: one in response to the exposure of mouse lungs to SARS-CoV-2 particles in the absence of productive viral replication, and the second in response to a productive infection. This approach expands our knowledge on the role of type-1 interferon signaling in COVID-19 disease, and can be further implemented for a range of COVID-19 studies and drug development.
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:HEK293T cells overexpressing hACE2 were infected by SARS-CoV-2 (WA1) and small RNA-seq was performed to profile small RNAs in response to SARS-COV-2 infection
Project description:HEK293T stable express hACE2 was infected by SARS-CoV-2 (WA1) and RNA-seq was performed to profile host gene expression in response to SARS-COV-2 infection