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Nat Commun ; 12(1): 5152, 2021 08 26.
Article in English | MEDLINE | ID: covidwho-1376195


The immunological features that distinguish COVID-19-associated acute respiratory distress syndrome (ARDS) from other causes of ARDS are incompletely understood. Here, we report the results of comparative lower respiratory tract transcriptional profiling of tracheal aspirate from 52 critically ill patients with ARDS from COVID-19 or from other etiologies, as well as controls without ARDS. In contrast to a "cytokine storm," we observe reduced proinflammatory gene expression in COVID-19 ARDS when compared to ARDS due to other causes. COVID-19 ARDS is characterized by a dysregulated host response with increased PTEN signaling and elevated expression of genes with non-canonical roles in inflammation and immunity. In silico analysis of gene expression identifies several candidate drugs that may modulate gene expression in COVID-19 ARDS, including dexamethasone and granulocyte colony stimulating factor. Compared to ARDS due to other types of viral pneumonia, COVID-19 is characterized by impaired interferon-stimulated gene (ISG) expression. The relationship between SARS-CoV-2 viral load and expression of ISGs is decoupled in patients with COVID-19 ARDS when compared to patients with mild COVID-19. In summary, assessment of host gene expression in the lower airways of patients reveals distinct immunological features of COVID-19 ARDS.

COVID-19/genetics , RNA/genetics , Respiratory Distress Syndrome/genetics , Trachea/immunology , Adult , Aged , Aged, 80 and over , COVID-19/immunology , COVID-19/virology , Case-Control Studies , Cohort Studies , Critical Illness , Cytokines/genetics , Cytokines/immunology , Female , Gene Expression Profiling , Humans , Male , Middle Aged , RNA/metabolism , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , SARS-CoV-2/physiology , Sequence Analysis, RNA
PLoS Pathog ; 17(1): e1009195, 2021 01.
Article in English | MEDLINE | ID: covidwho-1034958


SARS-CoV-2 emerged in late 2019 and resulted in the ongoing COVID-19 pandemic. Several animal models have been rapidly developed that recapitulate the asymptomatic to moderate disease spectrum. Now, there is a direct need for additional small animal models to study the pathogenesis of severe COVID-19 and for fast-tracked medical countermeasure development. Here, we show that transgenic mice expressing the human SARS-CoV-2 receptor (angiotensin-converting enzyme 2 [hACE2]) under a cytokeratin 18 promoter (K18) are susceptible to SARS-CoV-2 and that infection resulted in a dose-dependent lethal disease course. After inoculation with either 104 TCID50 or 105 TCID50, the SARS-CoV-2 infection resulted in rapid weight loss in both groups and uniform lethality in the 105 TCID50 group. High levels of viral RNA shedding were observed from the upper and lower respiratory tract and intermittent shedding was observed from the intestinal tract. Inoculation with SARS-CoV-2 resulted in upper and lower respiratory tract infection with high infectious virus titers in nasal turbinates, trachea and lungs. The observed interstitial pneumonia and pulmonary pathology, with SARS-CoV-2 replication evident in pneumocytes, were similar to that reported in severe cases of COVID-19. SARS-CoV-2 infection resulted in macrophage and lymphocyte infiltration in the lungs and upregulation of Th1 and proinflammatory cytokines/chemokines. Extrapulmonary replication of SARS-CoV-2 was observed in the cerebral cortex and hippocampus of several animals at 7 DPI but not at 3 DPI. The rapid inflammatory response and observed pathology bears resemblance to COVID-19. Additionally, we demonstrate that a mild disease course can be simulated by low dose infection with 102 TCID50 SARS-CoV-2, resulting in minimal clinical manifestation and near uniform survival. Taken together, these data support future application of this model to studies of pathogenesis and medical countermeasure development.

Angiotensin-Converting Enzyme 2/genetics , COVID-19/genetics , COVID-19/pathology , Keratin-18/genetics , Angiotensin-Converting Enzyme 2/immunology , Animals , COVID-19/immunology , COVID-19/virology , Disease Models, Animal , Female , Humans , Keratin-18/immunology , Lung/immunology , Lung/pathology , Lymphocytes/immunology , Macrophages/immunology , Male , Mice , Mice, Transgenic , Promoter Regions, Genetic , SARS-CoV-2/physiology , Trachea/immunology , Trachea/virology
J Exp Med ; 217(12)2020 12 07.
Article in English | MEDLINE | ID: covidwho-759876


Severe COVID-19 patients develop acute respiratory distress syndrome that may progress to cytokine storm syndrome, organ dysfunction, and death. Considering that neutrophil extracellular traps (NETs) have been described as important mediators of tissue damage in inflammatory diseases, we investigated whether NETs would be involved in COVID-19 pathophysiology. A cohort of 32 hospitalized patients with a confirmed diagnosis of COVID-19 and healthy controls were enrolled. The concentration of NETs was augmented in plasma, tracheal aspirate, and lung autopsies tissues from COVID-19 patients, and their neutrophils released higher levels of NETs. Notably, we found that viable SARS-CoV-2 can directly induce the release of NETs by healthy neutrophils. Mechanistically, NETs triggered by SARS-CoV-2 depend on angiotensin-converting enzyme 2, serine protease, virus replication, and PAD-4. Finally, NETs released by SARS-CoV-2-activated neutrophils promote lung epithelial cell death in vitro. These results unravel a possible detrimental role of NETs in the pathophysiology of COVID-19. Therefore, the inhibition of NETs represents a potential therapeutic target for COVID-19.

Betacoronavirus/physiology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Extracellular Traps/physiology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , A549 Cells , Adult , Angiotensin-Converting Enzyme 2 , COVID-19 , Cell Death , Coronavirus Infections/blood , Coronavirus Infections/pathology , Epithelial Cells/pathology , Epithelial Cells/virology , Female , HeLa Cells , Humans , Male , Neutrophil Activation , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/blood , Pneumonia, Viral/pathology , SARS-CoV-2 , Serine Proteases/metabolism , Suction , Trachea/immunology