Project description:SARS-CoV-2 infection can cause persistent respiratory sequelae, as seen in long COVID. However, the underlying mechanisms remain unclear. To investigate pulmonary cellular and transcriptomic changes mediated by SARS-CoV-2 and influenza infection, we characterized the SARS-CoV-2-infected K18-hACE2 (K18) mice and compared their lung recovery with a mouse-adapted influenza model and verified the finding in SARS-CoV-2-infected nonhuman primates and in fatal human COVID-19 cases. K18-hACE2 mice infected with a sub-lethal dose of SARS-CoV-2 lost body weight from 1 - 8 days post-infection (DPI), and then gradually returned to baseline weight between 8 -13 DPI. Infected mice showed patchy pneumonia associated with histiocytic inflammation, collagen deposition, and increased pulmonary interferon and inflammatory response signature gene changes at 21 and 45 DPI. Transcriptomic analyses revealed that compared to influenza-infected mice, SARS-CoV-2-infected mice had reduced interferon-gamma/alpha responses at 4 DPI and failed to induce keratin 5 (Krt5) at 6 DPI in lung, a marker of nascent pulmonary progenitor cells. They also showed reduced activation of epithelial-to-mesenchymal transition and apical junction pathways compared to influenza (Flu)-infected mice. Histologically, influenza- but not SARS-CoV-2- infected mice showed extensive Krt5+ “pods” structure co-stained with stem cell markers Trp63/ NGFR proliferated in the pulmonary consolidation area at both 7 and 14 DPI, with regression at 21 DPI. These Krt5+ “pods” and proliferative stem cells were not observed in SARS-CoV-2 infection in the lungs of humans or nonhuman primates. These results suggest that SARS-CoV-2 infection fails to induce nascent Krt5+ cell proliferation in consolidated regions, leading to incomplete repair of the injured lung which may underlie the persistent clinical symptoms of long COVID.
Project description:SARS-CoV-2 infection can cause persistent respiratory sequelae, as seen in long COVID. However, the underlying mechanisms remain unclear. To investigate pulmonary cellular and transcriptomic changes mediated by SARS-CoV-2 and influenza infection, we characterized the SARS-CoV-2-infected K18-hACE2 (K18) mice and compared their lung recovery with a mouse-adapted influenza model and verified the finding in SARS-CoV-2-infected nonhuman primates and in fatal human COVID-19 cases. K18-hACE2 mice infected with a sub-lethal dose of SARS-CoV-2 lost body weight from 1 - 8 days post-infection (DPI), and then gradually returned to baseline weight between 8 -13 DPI. Infected mice showed patchy pneumonia associated with histiocytic inflammation, collagen deposition, and increased pulmonary interferon and inflammatory response signature gene changes at 21 and 45 DPI. Transcriptomic analyses revealed that compared to influenza-infected mice, SARS-CoV-2-infected mice had reduced interferon-gamma/alpha responses at 4 DPI and failed to induce keratin 5 (Krt5) at 6 DPI in lung, a marker of nascent pulmonary progenitor cells. They also showed reduced activation of epithelial-to-mesenchymal transition and apical junction pathways compared to influenza (Flu)-infected mice. Histologically, influenza- but not SARS-CoV-2- infected mice showed extensive Krt5+ “pods” structure co-stained with stem cell markers Trp63/ NGFR proliferated in the pulmonary consolidation area at both 7 and 14 DPI, with regression at 21 DPI. These Krt5+ “pods” and proliferative stem cells were not observed in SARS-CoV-2 infection in the lungs of humans or nonhuman primates. These results suggest that SARS-CoV-2 infection fails to induce nascent Krt5+ cell proliferation in consolidated regions, leading to incomplete repair of the injured lung which may underlie the persistent clinical symptoms of long COVID.
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:To further identify and understand the molecular and immunological correlates of pathology for SARS-CoV infection, we infected 129/S6/SvEv or B129 mice with the TOR2 strain of SARS-CoV. SARS-CoV was detected in the lung and nasal turbinates of infected mice peaking at 1 day post infection (DPI) in both tissues before decreasing rapidly to levels below detection at 7 DPI and 3 DPI, respectively. Pulmonary lesions in virus-infected animals included bronchiolar, peribronchiolar, and perivascular foci of mild to moderate subacute inflammation. Chronic inflammation included inflammatory macrophages, lymphocytes, and plasma cells. Neutralizing antibodies appeared on 5 DPI (IgM); converting to IgG on 7 DPI. Despite the prevailing notion that SARS-CoV interferes with the induction of interferon (IFN) signaling, mice infected with SARS-CoV in vivo demonstrated significantly increased expression of innate antiviral interferon (IFN) response genes (IRGs) in the lungs during the first week of acute infection. By the end of the second week of infection, coordinated expression of MHC class I / II and antigen presentation genes occurred in correlation with declining viral titres. Collectively, the mouse data suggests that robust IFN-driven innate immune responses and a critical shift from innate to adaptive immune responses is necessary for clearance and recovery from SARS-CoV infection. Keywords: time course
Project description:Older age is a key predictor of severe COVID-19. To gain insight into this relationship, especially with respect to immune responses, we utilized the rhesus macaque model of SARS-CoV-2 infection. Two cohorts of eight older (16-23 years) and eight younger (3-5 years) rhesus macaques were inoculated with SARS-CoV-2. Four animals per group were euthanized at 7- and 21-days post inoculation (dpi). Our time-resolved evaluation included viral RNA quantification, clinical observations, thoracic radiographs, single-cell transcriptomics, multiparameter flow cytometry, multiplex immunohistochemistry, cytokine detection, and lipidomics analysis. Differences in clinical signs, pulmonary infiltrates, and virus replication dynamics were limited between age cohorts. Transcriptional signatures of inflammation-associated genes in cells isolated from bronchoalveolar lavage fluid at 3 dpi revealed efficient mounting of innate immune defenses in both younger and older animals. These findings suggest that age does not substantially skew major facets of acute disease in this model. However, age-specific divergence of immune responses emerged during the post-acute phase of infection (7-21 dpi). Older animals exhibited sustained local inflammatory innate responses while local effector T-cell responses were induced earlier in the younger animals. Circulating lipid mediator and cytokine levels highlighted increased repair-associated signals in the younger animals, in contrast to persistent pro-inflammatory responses in the older animals. In summary, despite similar disease outcomes, multi-omics profiling in SARS-CoV-2-infected rhesus macaques suggests that age may delay or impair the induction of anti-viral cellular immune responses and delay efficient return to immune homeostasis following acute infection.
Project description:Purpose:To determine the effect of SARS-CoV-2 infection on AhR signaling, we performed single-cell RNAseq (scRNA-Seq) from macaque lung tissue infected with SARS-CoV-2. Methods: Rhesus monkeys (3-5 kg, 3-5years old) were used for this study. One monkey is infected by intragastric administration with 1x 10^7 PFU of SARS-CoV-2 in 1mL of PBS, and another monkey was intranasally injected with 1x10^6 of SARS-CoV-2 in 200 µl of PBS. One monkey was intranasally and intragastrically treated with PBS as a control. We analyzed the tissues collected on the 4 dpi following Intranasal and intragastrical inoculation. Single-cell sequencing of were sequenced by an Illumina Novaseq6000 sequencer, the sequencing depth of each cell was at least 100,000 reads, and the paired-end 150 bp (PE150) reading strategy was adopted. Results and Conclusions: The scRNA-Seq results showed that the increased expression of upstream gene IDO1 and downstream transcriptional targets CYP1A1 and CYP1B1 of AhR in response to SARS-CoV-2 infection.
Project description:The mechanisms by which pulmonary lesions and fibrosis are generated during SARS-CoV infection are not known. Using high-throughput mRNA profiling, we examined the transcriptional response of wild-type (WT), type I interferon receptor knockout (IFNAR1−/−), and STAT1 knockout (STAT1−/−) mice infected with a recombinant mouse-adapted SARS-CoV (rMA15) to better understand the contribution of specific gene expression changes to disease progression. Ten week old 129S6/SvEv wild-type, STAT1−/− (Taconic Farms, Germantown, NY), and IFNAR1−/− mice bred on a 129SvEv background were anesthetized with a ketamine and infected intranasally with either phosphate-buffered saline (PBS) alone (Invitrogen, Carlsbad, CA) or 1 × 10^5 PFU rMA15-PBS. Mice were euthanized and left lungs were harvested from individual mice (a total of 3 infected mice from each strain) at days 2, 5, and 9 postinfection (dpi) for microarray analyses. Lung samples were taken from mock-infected animals from each of the strains at 5 dpi.
Project description:RNA isolated from draining tracheobronchial lymph nodes (TBLN) from 5-week old pigs, either clinically infected with a feral isolate of Pseudorabies virus or uninfected were interrogated using Illumina Digital Gene Expression Tag Profiling. Over 100 million tag sequences were observed, representing 4,064,189 unique 21-base sequences collected from TBLN at time points 1, 3, 6 and 14 days post-infection (dpi) RNA isolated from draining tracheobronchial lymph nodes (TBLN) from 5-week old pigs (% per group pooled), either clinically infected with feral isolate FS268 of Pseudorabies virus or uninfected at 1, 3, 6, and 14 days post inoculation. Over 100 million tag sequences were observed, representing 4,064,189 unique 21-base sequences.
Project description:Single-cell transcriptome of bronchoalveolar lavage fluid cells longitudinally obtained from SARS-CoV-2-infected ferrets was analyzed. Changes in cell proportions and characteristics in uninfected control, at 2 days post-infection (dpi), and 5 dpi were noted. Macrophages were classified into the subpopulations with dynamic changes quantitatively and qualitatively over time. Fundamental aspects of the immune response dynamics provoked by SARS-CoV-2 infection were highlighted in this study.