Upper airway gene expression differentiates COVID-19 from other acute respiratory illnesses and reveals suppression of innate immune responses by SARS-CoV-2.
ABSTRACT: We studied the host transcriptional response to SARS-CoV-2 by performing metagenomic sequencing of upper airway samples in 238 patients with COVID-19, other viral or non-viral acute respiratory illnesses (ARIs). Compared to other viral ARIs, COVID-19 was characterized by a diminished innate immune response, with reduced expression of genes involved in toll-like receptor and interleukin signaling, chemokine binding, neutrophil degranulation and interactions with lymphoid cells. Patients with COVID-19 also exhibited significantly reduced proportions of neutrophils and macrophages, and increased proportions of goblet, dendritic and B-cells, compared to other viral ARIs. Using machine learning, we built 26-, 10- and 3-gene classifiers that differentiated COVID-19 from other acute respiratory illnesses with AUCs of 0.980, 0.950 and 0.871, respectively. Classifier performance was stable at low viral loads, suggesting utility in settings where direct detection of viral nucleic acid may be unsuccessful. Taken together, our results illuminate unique aspects of the host transcriptional response to SARS-CoV-2 in comparison to other respiratory viruses and demonstrate the feasibility of COVID-19 diagnostics based on patient gene expression.
Project description:We studied the host transcriptional response to SARS-CoV-2 by performing metagenomic sequencing of upper airway samples in 234 patients with COVID-19 (n=93), other viral (n=100) or non-viral (n=41) acute respiratory illnesses (ARIs). Compared to other viral ARIs, COVID-19 was characterized by a diminished innate immune response, with reduced expression of genes involved in toll-like receptor and interleukin signaling, chemokine binding, neutrophil degranulation and interactions with lymphoid cells. Patients with COVID-19 also exhibited significantly reduced proportions of neutrophils, macrophages, and increased proportions of goblet, dendritic and B-cells, compared to other viral ARIs. Using machine learning, we built 27-, 10- and 3-gene classifiers that differentiated COVID-19 from other acute respiratory illnesses with AUCs of 0.981, 0.954 and 0.885, respectively. Classifier performance was stable at low viral loads, suggesting utility in settings where direct detection of viral nucleic acid may be unsuccessful. Taken together, our results illuminate unique aspects of the host transcriptional response to SARS-CoV-2 in comparison to other respiratory viruses and demonstrate the feasibility of COVID-19 diagnostics based on patient gene expression. Overall design: Comparing host transcriptional response to SARS-CoV-2 infection versus response to other respiratory viral infection or non-viral acute respiratory infection. > Submitter declares that the raw data are unavailable due to patient privacy concerns. The raw data may be submited to dbGAP if feasible. <
Project description:SARS-CoV-2 infection is characterized by peak viral load in the upper airway prior to or at the time of symptom onset, an unusual feature that has enabled widespread transmission of the virus and precipitated a global pandemic. How SARS-CoV-2 is able to achieve high titer in the absence of symptoms remains unclear. Here, we examine the upper airway host transcriptional response in patients with COVID-19 (n?=?93), other viral (n?=?41) or non-viral (n?=?100) acute respiratory illnesses (ARIs). Compared with other viral ARIs, COVID-19 is characterized by a pronounced interferon response but attenuated activation of other innate immune pathways, including toll-like receptor, interleukin and chemokine signaling. The IL-1 and NLRP3 inflammasome pathways are markedly less responsive to SARS-CoV-2, commensurate with a signature of diminished neutrophil and macrophage recruitment. This pattern resembles previously described distinctions between symptomatic and asymptomatic viral infections and may partly explain the propensity for pre-symptomatic transmission in COVID-19. We further use machine learning to build 27-, 10- and 3-gene classifiers that differentiate COVID-19 from other ARIs with AUROCs of 0.981, 0.954 and 0.885, respectively. Classifier performance is stable across a wide range of viral load, suggesting utility in mitigating false positive or false negative results of direct SARS-CoV-2 tests.
Project description:BACKGROUND:Emerging data on the clinical presentation, diagnostics, and outcomes of patients with COVID-19 have largely been presented as case series. Few studies have compared these clinical features and outcomes of COVID-19 to other acute respiratory illnesses. METHODS:We examined all patients presenting to an emergency department in San Francisco, California between February 3 and March 31, 2020 with an acute respiratory illness who were tested for SARS-CoV-2. We determined COVID-19 status by PCR and metagenomic next generation sequencing (mNGS). We compared demographics, comorbidities, symptoms, vital signs, and laboratory results including viral diagnostics using PCR and mNGS. Among those hospitalized, we determined differences in treatment (antibiotics, antivirals, respiratory support) and outcomes (ICU admission, ICU interventions, acute respiratory distress syndrome, cardiac injury). FINDINGS:In a cohort of 316 patients, 33 (10%) tested positive for SARS-CoV-2; 31 patients, all without COVID-19, tested positive for another respiratory virus (16%). Among patients with additional viral testing, no co-infections with SARS-CoV-2 were identified by PCR or mNGS. Patients with COVID-19 reported longer symptoms duration (median 7 vs. 3 days), and were more likely to report fever (82% vs. 44%), fatigue (85% vs. 50%), and myalgias (61% vs 27%); p<0.001 for all comparisons. Lymphopenia (55% vs 34%, p=0.018) and bilateral opacities on initial chest radiograph (55% vs. 24%, p=0.001) were more common in patients with COVID-19. Patients with COVID-19 were more often hospitalized (79% vs. 56%, p=0.014). Of 186 hospitalized patients, patients with COVID-19 had longer hospitalizations (median 10.7d vs. 4.7d, p<0.001) and were more likely to develop ARDS (23% vs. 3%, p<0.001). Most comorbidities, home medications, signs and symptoms, vital signs, laboratory results, treatment, and outcomes did not differ by COVID-19 status. INTERPRETATION:While we found differences in clinical features of COVID-19 compared to other acute respiratory illnesses, there was significant overlap in presentation and comorbidities. Patients with COVID-19 were more likely to be admitted to the hospital, have longer hospitalizations and develop ARDS, and were unlikely to have co-existent viral infections. These findings enhance understanding of the clinical characteristics of COVID-19 in comparison to other acute respiratory illnesses. ?.
Project description:Background:Most data on the clinical presentation, diagnostics, and outcomes of patients with COVID-19 have been presented as case series without comparison to patients with other acute respiratory illnesses. Methods:We examined emergency department patients between February 3 and March 31, 2020 with an acute respiratory illness who were tested for SARS-CoV-2. We determined COVID-19 status by PCR and metagenomic next generation sequencing (mNGS). We compared clinical presentation, diagnostics, treatment, and outcomes. Findings:Among 316 patients, 33 tested positive for SARS-CoV-2; 31 without COVID-19 tested positive for another respiratory virus. Among patients with additional viral testing (27/33), no SARS-CoV-2 co-infections were identified. Compared to those who tested negative, patients with COVID-19 reported longer symptoms duration (median 7d vs. 3d, p < 0.001). Patients with COVID-19 were more often hospitalized (79% vs. 56%, p = 0.014). When hospitalized, patients with COVID-19 had longer hospitalizations (median 10.7d vs. 4.7d, p < 0.001) and more often developed ARDS (23% vs. 3%, p < 0.001). Most comorbidities, medications, symptoms, vital signs, laboratories, treatments, and outcomes did not differ by COVID-19 status. Interpretation:While we found differences in clinical features of COVID-19 compared to other acute respiratory illnesses, there was significant overlap in presentation and comorbidities. Patients with COVID-19 were more likely to be admitted to the hospital, have longer hospitalizations and develop ARDS, and were unlikely to have co-existent viral infections. Funding:National Center for Advancing Translational Sciences, National Heart Lung Blood Institute, National Institute of Allergy and Infectious Diseases, Chan Zuckerberg Biohub, Chan Zuckerberg Initiative.
Project description:The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the related disease (COVID-19) has spread rapidly to pandemic proportions, increasing the demands on healthcare systems for the containment and management of COVID-19. One of the critical issues to be addressed is the improvement in laboratory diagnosis and screening of large portions of the population to stop the virus spreading. Currently, the laboratory diagnosis of SARS-CoV-2 infection and the related disease is based on the research of viral RNA with rt-PCR methods in upper and lower respiratory airways. Serological tests to detect SARS-CoV-2 antibodies could help physicians and healthcare workers to support COVID-19 diagnosis and follow-up and perform population screening. Our review, using MEDLINE and EMBASE, summarizes the current knowledge of direct and serological tests performed to research RNA, antigens, or antibodies for SARS-CoV-2, evaluating the advantages and drawbacks for specific tests.
Project description:SARS-CoV-2 has caused a historic pandemic of respiratory disease (COVID-19) and current evidence suggests severe disease is associated with dysregulated immunity within the respiratory tract1,2. However, the innate immune mechanisms that mediate protection during COVID-19 are not well defined. Here we characterize a mouse model of SARS-CoV-2 infection and find that early CCR2-dependent infiltration of monocytes restricts viral burden in the lung. We find that a recently developed mouse-adapted MA-SARS-CoV-2 strain, as well as the emerging B.1.351 variant, trigger an inflammatory response in the lung characterized by expression of pro-inflammatory cytokines and interferon-stimulated genes. Using intravital antibody labeling, we demonstrate that MA-SARS-CoV-2 infection leads to increases in circulating monocytes and an influx of CD45+ cells into the lung parenchyma that is dominated by monocyte-derived cells. scRNA-seq analysis of lung homogenates identified a hyper-inflammatory monocyte profile. We utilize this model to demonstrate that mechanistically, CCR2 signaling promotes infiltration of classical monocytes into the lung and expansion of monocyte-derived cells. Parenchymal monocyte-derived cells appear to play a protective role against MA-SARS-CoV-2, as mice lacking CCR2 showed higher viral loads in the lungs, increased lung viral dissemination, and elevated inflammatory cytokine responses. These studies have identified a CCR2-monocyte axis that is critical for promoting viral control and restricting inflammation within the respiratory tract during SARS-CoV-2 infection. Overall design: 8 samples in total corresponding to different mice. 4 samples are from mock, control mice. 4 samples are from SARS-CoV-2 infected mice.
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. Overall design: 8 samples of mouse lung: Lenti-control_1* Lenti-control 2 * Lenti-hACE2_1* Lenti-hACE2_2* Lenti-control+SARS-CoV-2(dpi 2)* Lenti-control+SARS-CoV-2(dpi 4)* Lenti-hACE2+SARS-CoV-2(dpi 2)** Lenti- hACE2+SARS-CoV-2(dpi 4)**
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the coronavirus disease-19 (COVID-19) pandemic, was identified in late 2019 and went on to cause over 3.3 million deaths in 15 months. To date, targeted antiviral interventions against COVID-19 are limited. The spectrum of SARS-CoV-2 infection ranges from asymptomatic to fatal disease. However, the reasons for varying outcomes to SARS-CoV-2 infection are yet to be elucidated. Here we show that an endogenously activated interferon lambda (IFNλ) pathway leads to resistance against SARS-CoV-2 infection. Using a well-differentiated primary nasal epithelial cell (WD-PNEC) model from multiple adult donors, we discovered that susceptibility to SARS-CoV-2 infection, but not respiratory syncytial virus (RSV) infection, varied. One of four donors was resistant to SARS-CoV-2 infection. High baseline IFNλ expression levels and associated interferon stimulated genes correlated with resistance to SARS-CoV-2 infection. Inhibition of the JAK/STAT pathway in WD-PNECs with high endogenous IFNλ secretion resulted in higher SARS-CoV-2 titres. Conversely, prophylactic IFNλ treatment of WD-PNECs susceptible to infection resulted in reduced viral titres. An endogenously activated IFNλ response, possibly due to genetic differences, may be one explanation for the differences in susceptibility to SARS-CoV-2 infection in humans. Overall design: Well-differentiated primary nasal epithelial cells from different human healthy donors were mock-infected and infected with SARS-CoV-2 and gene expression was measured and compared at 48 hours and 96 hours post infection
Project description:Coronavirus disease 2019 (COVID-19) is a disease that causes fatal disorders including severe pneumonia. To develop a therapeutic drug for COVID-19, a model that can reproduce the viral life cycle and can evaluate the drug efficacy of anti-viral drugs is essential. In this study, we established a method to generate human bronchial organoids (hBO) from commercially available cryopreserved primary human bronchial epithelial cells (hBEpC) and examined whether they could be used as a model for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research. The hBO were found to contain basal, club, ciliated, and goblet cells. Also, angiotensin-converting enzyme 2 (ACE2), which is a receptor for SARS-CoV-2, and transmembrane serine proteinase 2 (TMPRSS2), which is an essential serine protease for priming spike protein of SARS-CoV-2, were highly expressed. After hBO were infected with SARS-CoV-2, remarkable amplification of the viral genome and the expression of spike protein of the virus was confirmed. In addition, cytotoxicity and pyknosis cells were observed due to the virus infection. Furthermore, treatment with camostat, an inhibitor of TMPRSS2, reduced the viral copy number to 2% of the control group. RNA-seq analyses revealed genes whose expression was altered by SARS-CoV-2 infection and camostat treatment. These results suggest that our hBO are acceptable for SARS-CoV-2 infection and replication, but also can be used as a model for COVID-19 drug discovery. Overall design: Total RNA was isolated from human bronchial organoids, primary human bronchial epithelial cells, and A549 cell, and then RNA-seq was performed. The human bronchial organoids were infected with SARS-CoV-2 in the presence of absence of camostat. At 5 days after the infection, total RNA was collected and RNA-seq was performed.
Project description:COVID-19 patients are generally asymptomatic during initial SARS-CoV-2 replication, but may suffer severe immunopathology after the virus has receded and blood monocytes have infiltrated the airways. In the bronchoalveolar lavage fluid from patients with severe COVID-19, lung-infiltrating monocytes expressed high mRNA levels encoding inflammatory mediators, including CXCL8and IL-1ß, and contained SARS-CoV-2transcripts. To study this process in more depth, we developed a novel organotypic model whereby primary human blood monocytes are transmigrated across a differentiated human lung epithelium infected by SARS-CoV-2. Infiltrating monocytes acquiredSARS-CoV-2 from the epithelium and upregulated expression and secretion of inflammatory mediators includingCXCL8 and IL-1ß, mirroring in vivo data. The JAK1/2inhibitor baricitinib gained emergency use authorization by the FDA for the treatment of COVID-19 originally in combination with the antiviral remdesivir, and recently as a stand-alone treatment. To explore the mechanisms by which baricitinib alone or in combination with remdesivir may result in more favorable disease outcomes, we leveraged this model to characterize viral burden, gene expression and inflammatory mediator secretion by lung epithelial cells and infiltrating monocytes. As expected, remdesivir decreased viral burden in both the epithelium and monocytes, while baricitinib enhanced antiviral signaling and decreased specific inflammatory mediators in monocytes. Combined use of baricitinib and remdesivir enhanced the rate of virus clearance from SARS-CoV-2-positivemonocytes. Taken together, baricitinib enhances the antiviral state of monocytes infiltrating the COVID-19 lung, while decreasing the expression of inflammatory mediators, thus limiting the likelihood of a cytokine storm and ensuing acute respiratory distress syndrome (ARDS). Overall design: To determine the relationship between airway epithelium, SARS-CoV-2 infection and airway monocytes we used an in vitro organotypic model to condition epithelial cells at air-liquid interface followed by infection with SARS-CoV-2 and transmgiration by primary blood monocytes.