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1.
Signal Transduct Target Ther ; 7(1): 29, 2022 01 28.
Article in English | MEDLINE | ID: covidwho-1655546

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted on mink farms between minks and humans in many countries. However, the systemic pathological features of SARS-CoV-2-infected minks are mostly unknown. Here, we demonstrated that minks were largely permissive to SARS-CoV-2, characterized by severe and diffuse alveolar damage, and lasted at least 14 days post inoculation (dpi). We first reported that infected minks displayed multiple organ-system lesions accompanied by an increased inflammatory response and widespread viral distribution in the cardiovascular, hepatobiliary, urinary, endocrine, digestive, and immune systems. The viral protein partially co-localized with activated Mac-2+ macrophages throughout the body. Moreover, we first found that the alterations in lipids and metabolites were correlated with the histological lesions in infected minks, especially at 6 dpi, and were similar to that of patients with severe and fatal COVID-19. Particularly, altered metabolic pathways, abnormal digestion, and absorption of vitamins, lipids, cholesterol, steroids, amino acids, and proteins, consistent with hepatic dysfunction, highlight metabolic and immune dysregulation. Enriched kynurenine in infected minks contributed to significant activation of the kynurenine pathway and was related to macrophage activation. Melatonin, which has significant anti-inflammatory and immunomodulating effects, was significantly downregulated at 6 dpi and displayed potential as a targeted medicine. Our data first illustrate systematic analyses of infected minks to recapitulate those observations in severe and fetal COVID-19 patients, delineating a useful animal model to mimic SARS-CoV-2-induced systematic and severe pathophysiological features and provide a reliable tool for the development of effective and targeted treatment strategies, vaccine research, and potential biomarkers.


Subject(s)
COVID-19/metabolism , Lung/metabolism , Macrophages, Alveolar/metabolism , Metabolome , Mink/virology , SARS-CoV-2/metabolism , Amino Acids/metabolism , Animals , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/genetics , COVID-19/pathology , Disease Models, Animal , Female , Humans , Lung/pathology , Lung/virology , Macrophages, Alveolar/pathology , Macrophages, Alveolar/virology , Melatonin/metabolism , Metabolic Networks and Pathways/genetics , Molecular Targeted Therapy/methods , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Sterols/metabolism , Virulence , Virus Replication/genetics
2.
Nature ; 595(7865): 114-119, 2021 07.
Article in English | MEDLINE | ID: covidwho-1207147

ABSTRACT

Respiratory failure is the leading cause of death in patients with severe SARS-CoV-2 infection1,2, but the host response at the lung tissue level is poorly understood. Here we performed single-nucleus RNA sequencing of about 116,000 nuclei from the lungs of nineteen individuals who died of COVID-19 and underwent rapid autopsy and seven control individuals. Integrated analyses identified substantial alterations in cellular composition, transcriptional cell states, and cell-to-cell interactions, thereby providing insight into the biology of lethal COVID-19. The lungs from individuals with COVID-19 were highly inflamed, with dense infiltration of aberrantly activated monocyte-derived macrophages and alveolar macrophages, but had impaired T cell responses. Monocyte/macrophage-derived interleukin-1ß and epithelial cell-derived interleukin-6 were unique features of SARS-CoV-2 infection compared to other viral and bacterial causes of pneumonia. Alveolar type 2 cells adopted an inflammation-associated transient progenitor cell state and failed to undergo full transition into alveolar type 1 cells, resulting in impaired lung regeneration. Furthermore, we identified expansion of recently described CTHRC1+ pathological fibroblasts3 contributing to rapidly ensuing pulmonary fibrosis in COVID-19. Inference of protein activity and ligand-receptor interactions identified putative drug targets to disrupt deleterious circuits. This atlas enables the dissection of lethal COVID-19, may inform our understanding of long-term complications of COVID-19 survivors, and provides an important resource for therapeutic development.


Subject(s)
COVID-19/pathology , COVID-19/virology , Lung/pathology , SARS-CoV-2/pathogenicity , Single-Cell Analysis , Aged , Aged, 80 and over , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/virology , Atlases as Topic , Autopsy , COVID-19/immunology , Case-Control Studies , Female , Fibroblasts/pathology , Fibrosis/pathology , Fibrosis/virology , Humans , Inflammation/pathology , Inflammation/virology , Macrophages/pathology , Macrophages/virology , Macrophages, Alveolar/pathology , Macrophages, Alveolar/virology , Male , Middle Aged , Plasma Cells/immunology , T-Lymphocytes/immunology
3.
J Clin Invest ; 131(4)2021 02 15.
Article in English | MEDLINE | ID: covidwho-1172781

ABSTRACT

Alveolar macrophages orchestrate the response to viral infections. Age-related changes in these cells may underlie the differential severity of pneumonia in older patients. We performed an integrated analysis of single-cell RNA-Seq data that revealed homogenous age-related changes in the alveolar macrophage transcriptome in humans and mice. Using genetic lineage tracing with sequential injury, heterochronic adoptive transfer, and parabiosis, we found that the lung microenvironment drove an age-related resistance of alveolar macrophages to proliferation that persisted during influenza A viral infection. Ligand-receptor pair analysis localized these changes to the extracellular matrix, where hyaluronan was increased in aged animals and altered the proliferative response of bone marrow-derived macrophages to granulocyte macrophage colony-stimulating factor (GM-CSF). Our findings suggest that strategies targeting the aging lung microenvironment will be necessary to restore alveolar macrophage function in aging.


Subject(s)
Aging/immunology , Cellular Microenvironment/immunology , Lung/immunology , Macrophages, Alveolar/immunology , Aging/pathology , Animals , Humans , Lung/pathology , Macrophages, Alveolar/pathology , Mice , Mice, Transgenic , RNA-Seq
4.
Immunity ; 54(3): 542-556.e9, 2021 03 09.
Article in English | MEDLINE | ID: covidwho-1101300

ABSTRACT

A combination of vaccination approaches will likely be necessary to fully control the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Here, we show that modified vaccinia Ankara (MVA) vectors expressing membrane-anchored pre-fusion stabilized spike (MVA/S) but not secreted S1 induced strong neutralizing antibody responses against SARS-CoV-2 in mice. In macaques, the MVA/S vaccination induced strong neutralizing antibodies and CD8+ T cell responses, and conferred protection from SARS-CoV-2 infection and virus replication in the lungs as early as day 2 following intranasal and intratracheal challenge. Single-cell RNA sequencing analysis of lung cells on day 4 after infection revealed that MVA/S vaccination also protected macaques from infection-induced inflammation and B cell abnormalities and lowered induction of interferon-stimulated genes. These results demonstrate that MVA/S vaccination induces neutralizing antibodies and CD8+ T cells in the blood and lungs and is a potential vaccine candidate for SARS-CoV-2.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , Genetic Vectors/genetics , SARS-CoV-2/immunology , Vaccines, DNA/immunology , Vaccinia virus/genetics , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigens, Viral/genetics , Antigens, Viral/immunology , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , COVID-19 Vaccines/genetics , Disease Models, Animal , Gene Expression , Gene Order , Immunophenotyping , Lung/immunology , Lung/pathology , Lung/virology , Macaca , Macrophages, Alveolar/immunology , Macrophages, Alveolar/metabolism , Macrophages, Alveolar/pathology , Mice , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , Vaccination/methods , Vaccines, DNA/genetics
5.
S Afr Med J ; 110(12): 1195-1200, 2020 10 19.
Article in English | MEDLINE | ID: covidwho-994151

ABSTRACT

BACKGROUND: An outbreak of a novel coronavirus in China in late 2019 has resulted in a global pandemic. The virus (SARS-CoV-2) causes a severe acute respiratory syndrome and had been responsible for >14 000 deaths in South Africa (SA) at the time of writing, 30 August 2020. Autopsies in our setting have not been prioritised owing to the infective risks for staff, resulting in a lack of information on the histopathology of the disease in the SA setting. Postmortem biopsies are relatively quick and easy to perform and reduce the infective risk posed by full autopsies. OBJECTIVES: To determine whether postmortem biopsies of lung tissue could be used to determine cause of death in lieu of full autopsies in patients dying from COVID-19. METHODS: We performed postmortem biopsies of lung tissue on 4 patients with SARS-CoV-2 confirmed by reverse transcriptase polymerase chain reaction who died in the Tygerberg Hospital (Cape Town, SA) intensive care unit (ICU) in June - July 2020, in order to determine their cause of death. The biopsies were performed in the ICU with the necessary personal protective equipment within 2 hours after death. Clinical information was obtained from the hospital records and the histopathology was reviewed by two consultant histopathologists. Microbiology and electron microscopy were also performed on this tissue. RESULTS: All 4 patients were aged >50 years and had multiple comorbidities. Pulmonary pathology was present in only 3 cases, and the findings were surprisingly heterogeneous. One case demonstrated several findings including diffuse alveolar damage, extensive fibrin thrombi in pulmonary arteries with pulmonary infarction, organising pneumonia and bronchopneumonia. Other findings included type 2 pneumocyte hyperplasia, intra-alveolar macrophages and squamous metaplasia. An organising pneumonia was present in 2 other cases, although these findings were not deemed to be severe enough to be the cause of death. Fibrin thrombi were present in pulmonary arteries of 3 cases. One case showed no significant acute pulmonary pathology. The cause of death could only be determined in 1 case. CONCLUSIONS: The pulmonary findings we observed are in keeping with those described in the international literature. However, the pathology was surprisingly heterogeneous between cases, and was only deemed severe enough to be the cause of death in 1 of 4 cases. While lung-targeted, standardised postmortem biopsies may be safe, easy to perform and provide useful insights into the disease, they are not suitable to replace full autopsies in determining cause of death.


Subject(s)
Biopsy , COVID-19/pathology , Lung Injury/pathology , Lung/pathology , Pulmonary Artery/pathology , Pulmonary Edema/pathology , Pulmonary Infarction/pathology , Thrombosis/pathology , Aged , Alveolar Epithelial Cells/pathology , Autopsy , C-Reactive Protein/metabolism , COVID-19/blood , COVID-19/mortality , Cause of Death , Comorbidity , Diabetes Mellitus, Type 2/epidemiology , Female , Fibrin Fibrinogen Degradation Products/metabolism , Giant Cells/pathology , Humans , Hypertension/epidemiology , Lymphocytes/pathology , Macrophages, Alveolar/pathology , Male , Middle Aged , Obesity/epidemiology , Procalcitonin/blood , SARS-CoV-2 , South Africa , Tertiary Care Centers
6.
Eur J Clin Invest ; 51(1): e13443, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-901035

ABSTRACT

BACKGROUND: To reveal detailed histopathological changes, virus distributions, immunologic properties and multi-omic features caused by SARS-CoV-2 in the explanted lungs from the world's first successful lung transplantation of a COVID-19 patient. MATERIALS AND METHODS: A total of 36 samples were collected from the lungs. Histopathological features and virus distribution were observed by optical microscope and transmission electron microscope (TEM). Immune cells were detected by flow cytometry and immunohistochemistry. Transcriptome and proteome approaches were used to investigate main biological processes involved in COVID-19-associated pulmonary fibrosis. RESULTS: The histopathological changes of the lung tissues were characterized by extensive pulmonary interstitial fibrosis and haemorrhage. Viral particles were observed in the cytoplasm of macrophages. CD3+ CD4- T cells, neutrophils, NK cells, γ/δ T cells and monocytes, but not B cells, were abundant in the lungs. Higher levels of proinflammatory cytokines iNOS, IL-1ß and IL-6 were in the area of mild fibrosis. Multi-omics analyses revealed a total of 126 out of 20,356 significant different transcription and 114 out of 8,493 protein expression in lung samples with mild and severe fibrosis, most of which were related to fibrosis and inflammation. CONCLUSIONS: Our results provide novel insight that the significant neutrophil/ CD3+ CD4- T cell/ macrophage activation leads to cytokine storm and severe fibrosis in the lungs of COVID-19 patient and may contribute to a better understanding of COVID-19 pathogenesis.


Subject(s)
COVID-19/pathology , Hemorrhage/pathology , Lung Transplantation , Lung/pathology , Lymph Nodes/pathology , Pulmonary Fibrosis/pathology , B-Lymphocytes/pathology , B-Lymphocytes/ultrastructure , B-Lymphocytes/virology , COVID-19/genetics , COVID-19/metabolism , COVID-19/surgery , Chromatography, Liquid , Flow Cytometry , Gene Expression Profiling , Humans , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Killer Cells, Natural/pathology , Killer Cells, Natural/ultrastructure , Killer Cells, Natural/virology , Lung/metabolism , Lung/ultrastructure , Lung/virology , Lymph Nodes/metabolism , Lymph Nodes/ultrastructure , Lymph Nodes/virology , Macrophages, Alveolar/pathology , Macrophages, Alveolar/ultrastructure , Macrophages, Alveolar/virology , Male , Middle Aged , Monocytes/pathology , Monocytes/ultrastructure , Monocytes/virology , Neutrophils/pathology , Neutrophils/ultrastructure , Neutrophils/virology , Nitric Oxide Synthase Type II/metabolism , Proteomics , Pulmonary Fibrosis/genetics , Pulmonary Fibrosis/metabolism , Pulmonary Fibrosis/surgery , RNA-Seq , SARS-CoV-2 , Severity of Illness Index , T-Lymphocytes/pathology , T-Lymphocytes/ultrastructure , T-Lymphocytes/virology , Tandem Mass Spectrometry
7.
Life Sci ; 258: 118166, 2020 Oct 01.
Article in English | MEDLINE | ID: covidwho-703163

ABSTRACT

In this paper, a model is proposed of the pathophysiological processes of COVID-19 starting from the infection of human type II alveolar epithelial cells (pneumocytes) by SARS-CoV-2 and culminating in the development of ARDS. The innate immune response to infection of type II alveolar epithelial cells leads both to their death by apoptosis and pyroptosis and to alveolar macrophage activation. Activated macrophages secrete proinflammatory cytokines and chemokines and tend to polarise into the inflammatory M1 phenotype. These changes are associated with activation of vascular endothelial cells and thence the recruitment of highly toxic neutrophils and inflammatory activated platelets into the alveolar space. Activated vascular endothelial cells become a source of proinflammatory cytokines and reactive oxygen species (ROS) and contribute to the development of coagulopathy, systemic sepsis, a cytokine storm and ARDS. Pulmonary activated platelets are also an important source of proinflammatory cytokines and ROS, as well as exacerbating pulmonary neutrophil-mediated inflammatory responses and contributing to systemic sepsis by binding to neutrophils to form platelet-neutrophil complexes (PNCs). PNC formation increases neutrophil recruitment, activation priming and extraversion of these immune cells into inflamed pulmonary tissue, thereby contributing to ARDS. Sequestered PNCs cause the development of a procoagulant and proinflammatory environment. The contribution to ARDS of increased extracellular histone levels, circulating mitochondrial DNA, the chromatin protein HMGB1, decreased neutrophil apoptosis, impaired macrophage efferocytosis, the cytokine storm, the toll-like receptor radical cycle, pyroptosis, necroinflammation, lymphopenia and a high Th17 to regulatory T lymphocyte ratio are detailed.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/physiopathology , Pneumonia, Viral/physiopathology , Respiratory Distress Syndrome/physiopathology , Alveolar Epithelial Cells/immunology , Alveolar Epithelial Cells/pathology , Animals , Betacoronavirus/immunology , COVID-19 , Coronavirus Infections/complications , Coronavirus Infections/immunology , Coronavirus Infections/therapy , Humans , Immunity, Innate , Inflammation/etiology , Inflammation/immunology , Inflammation/physiopathology , Inflammation/therapy , Macrophage Activation , Macrophages, Alveolar/immunology , Macrophages, Alveolar/pathology , Neutrophil Activation , Pandemics , Platelet Activation , Pneumonia, Viral/complications , Pneumonia, Viral/immunology , Pneumonia, Viral/therapy , Respiratory Distress Syndrome/etiology , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/therapy , SARS-CoV-2 , Thrombophilia/etiology , Thrombophilia/immunology , Thrombophilia/physiopathology , Thrombophilia/therapy
8.
Front Immunol ; 11: 1625, 2020.
Article in English | MEDLINE | ID: covidwho-688729

ABSTRACT

COVID-19 is a clinical syndrome ranging from mild symptoms to severe pneumonia that often leads to respiratory failure, need for mechanical ventilation, and death. Most of the lung damage is driven by a surge in inflammatory cytokines [interleukin-6, interferon-γ, and granulocyte-monocyte stimulating factor (GM-CSF)]. Blunting this hyperinflammation with immunomodulation may lead to clinical improvement. GM-CSF is produced by many cells, including macrophages and T-cells. GM-CSF-derived signals are involved in differentiation of macrophages, including alveolar macrophages (AMs). In animal models of respiratory infections, the intranasal administration of GM-CSF increased the proliferation of AMs and improved outcomes. Increased levels of GM-CSF have been recently described in patients with COVID-19 compared to healthy controls. While GM-CSF might be beneficial in some circumstances as an appropriate response, in this case the inflammatory response is maladaptive by virtue of being later and disproportionate. The inhibition of GM-CSF signaling may be beneficial in improving the hyperinflammation-related lung damage in the most severe cases of COVID-19. This blockade can be achieved through antagonism of the GM-CSF receptor or the direct binding of circulating GM-CSF. Initial findings from patients with COVID-19 treated with a single intravenous dose of mavrilimumab, a monoclonal antibody binding GM-CSF receptor α, showed oxygenation improvement and shorter hospitalization. Prospective, randomized, placebo-controlled trials are ongoing. Anti-GM-CSF monoclonal antibodies, TJ003234 and gimsilumab, will be tested in clinical trials in patients with COVID-19, while lenzilumab received FDA approval for compassionate use. These trials will help inform whether blunting the inflammatory signaling provided by the GM-CSF axis in COVID-19 is beneficial.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Betacoronavirus/immunology , Coronavirus Infections , Drug Delivery Systems , Granulocyte-Macrophage Colony-Stimulating Factor/immunology , Pandemics , Pneumonia, Viral , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/antagonists & inhibitors , Animals , COVID-19 , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Disease Models, Animal , Granulocyte-Macrophage Colony-Stimulating Factor/antagonists & inhibitors , Humans , Inflammation/drug therapy , Inflammation/immunology , Inflammation/pathology , Macrophages, Alveolar/immunology , Macrophages, Alveolar/pathology , Pneumonia, Viral/drug therapy , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/immunology , SARS-CoV-2 , Signal Transduction/drug effects , Signal Transduction/immunology , T-Lymphocytes/immunology , T-Lymphocytes/pathology
10.
EBioMedicine ; 57: 102833, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-613483

ABSTRACT

BACKGROUND: The novel coronavirus pneumonia COVID-19 caused by SARS-CoV-2 infection could lead to a series of clinical symptoms and severe illnesses, including acute respiratory distress syndrome (ARDS) and fatal organ failure. We report the fundamental pathological investigation in the lungs and other organs of fatal cases for the mechanistic understanding of severe COVID-19 and the development of specific therapy in these cases. METHODS: The autopsy and pathological investigations of specimens were performed on bodies of two deceased cases with COVID-19. Gross anatomy and histological investigation by Hematoxylin and eosin (HE) stained were reviewed on each patient. Alcian blue/periodic acid-Schiff (AB-PAS) staining and Masson staining were performed for the examinations of mucus, fibrin and collagen fiber in lung tissues. Immunohistochemical staining was performed on the slides of lung tissues from two patients. Real-time PCR was performed to detect the infection of SARS-CoV-2. Flow cytometry analyses were performed to detect the direct binding of S protein and the expression of ACE2 on the cell surface of macrophages. FINDINGS: The main pathological features in lungs included extensive impairment of type I alveolar epithelial cells and atypical hyperplasia of type II alveolar cells, with formation of hyaline membrane, focal hemorrhage, exudation and pulmonary edema, and pulmonary consolidation. The mucous plug with fibrinous exudate in the alveoli and the dysfunction of alveolar macrophages were characteristic abnormalities. The type II alveolar epithelial cells and macrophages in alveoli and pulmonary hilum lymphoid tissue were infected by SARS-CoV-2. S protein of SARS-CoV-2 directly bound to the macrophage via the S-protein-ACE2 interaction. INTERPRETATION: Infection of alveolar macrophage by SARS-CoV-2 might be drivers of the "cytokine storm", which might result in damages in pulmonary tissues, heart and lung, and lead to the failure of multiple organs . FUNDING: Shanghai Guangci Translational Medical Research Development Foundation, Shanghai, China.


Subject(s)
Alveolar Epithelial Cells/pathology , Coronavirus Infections/pathology , Cytokine Release Syndrome/pathology , Lung/pathology , Macrophages, Alveolar/pathology , Pneumonia, Viral/pathology , Angiotensin-Converting Enzyme 2 , Autopsy , Betacoronavirus , COVID-19 , China , Coronavirus Infections/mortality , Cytokine Release Syndrome/mortality , Cytokines/blood , Cytokines/metabolism , Female , Humans , Hyperplasia/pathology , Male , Middle Aged , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/mortality , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism
11.
J Immunol ; 205(2): 307-312, 2020 07 15.
Article in English | MEDLINE | ID: covidwho-542361

ABSTRACT

The inflammatory response to severe acute respiratory syndrome-related coronavirus 2 infection has a direct impact on the clinical outcomes of coronavirus disease 2019 patients. Of the many innate immune pathways that are engaged by severe acute respiratory syndrome-related coronavirus 2, we highlight the importance of the inflammasome pathway. We discuss available pharmaceutical agents that target a critical component of inflammasome activation, signaling leading to cellular pyroptosis, and the downstream cytokines as a promising target for the treatment of severe coronavirus disease 2019-associated diseases.


Subject(s)
Antiviral Agents/pharmacology , Inflammasomes/drug effects , Pyroptosis/drug effects , Animals , Antiviral Agents/immunology , Betacoronavirus/physiology , COVID-19 , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Humans , Immunity, Innate , Intercellular Signaling Peptides and Proteins/metabolism , Macrophages, Alveolar/pathology , Pandemics , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , SARS Virus/physiology , SARS-CoV-2 , Signal Transduction
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