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1.
PLoS Pathog ; 18(2): e1010268, 2022 02.
Article in English | MEDLINE | ID: covidwho-1753212

ABSTRACT

Next generation sequencing has revealed the presence of numerous RNA viruses in animal reservoir hosts, including many closely related to known human pathogens. Despite their zoonotic potential, most of these viruses remain understudied due to not yet being cultured. While reverse genetic systems can facilitate virus rescue, this is often hindered by missing viral genome ends. A prime example is Lloviu virus (LLOV), an uncultured filovirus that is closely related to the highly pathogenic Ebola virus. Using minigenome systems, we complemented the missing LLOV genomic ends and identified cis-acting elements required for LLOV replication that were lacking in the published sequence. We leveraged these data to generate recombinant full-length LLOV clones and rescue infectious virus. Similar to other filoviruses, recombinant LLOV (rLLOV) forms filamentous virions and induces the formation of characteristic inclusions in the cytoplasm of the infected cells, as shown by electron microscopy. Known target cells of Ebola virus, including macrophages and hepatocytes, are permissive to rLLOV infection, suggesting that humans could be potential hosts. However, inflammatory responses in human macrophages, a hallmark of Ebola virus disease, are not induced by rLLOV. Additional tropism testing identified pneumocytes as capable of robust rLLOV and Ebola virus infection. We also used rLLOV to test antivirals targeting multiple facets of the replication cycle. Rescue of uncultured viruses of pathogenic concern represents a valuable tool in our arsenal for pandemic preparedness.


Subject(s)
Ebolavirus/genetics , Filoviridae Infections/virology , Filoviridae/genetics , Virus Replication , Animals , Cell Line , Chlorocebus aethiops , Genetic Complementation Test , Genome, Viral , Hemorrhagic Fever, Ebola/virology , Host Microbial Interactions , Humans , Inclusion Bodies/virology , Induced Pluripotent Stem Cells/virology , Macrophages/virology , RNA, Viral , Reverse Genetics , Vero Cells , Virion/genetics
2.
Viruses ; 14(2)2022 02 21.
Article in English | MEDLINE | ID: covidwho-1744920

ABSTRACT

Involvement of macrophages in the SARS-CoV-2-associated cytokine storm, the excessive secretion of inflammatory/anti-viral factors leading to the acute respiratory distress syndrome (ARDS) in COVID-19 patients, is unclear. In this study, we sought to characterize the interplay between the virus and primary human monocyte-derived macrophages (MDM). MDM were stimulated with recombinant IFN-α and/or infected with either live or UV-inactivated SARS-CoV-2 or with two reassortant influenza viruses containing external genes from the H1N1 PR8 strain and heterologous internal genes from a highly pathogenic avian H5N1 or a low pathogenic human seasonal H1N1 strain. Virus replication was monitored by qRT-PCR for the E viral gene for SARS-CoV-2 or M gene for influenza and TCID50 or plaque assay, and cytokine levels were assessed semiquantitatively with qRT-PCR and a proteome cytokine array. We report that MDM are not susceptible to SARS-CoV-2 whereas both influenza viruses replicated in MDM, albeit abortively. We observed a modest cytokine response in SARS-CoV-2 exposed MDM with notable absence of IFN-ß induction, which was instead strongly induced by the influenza viruses. Pre-treatment of MDM with IFN-α enhanced proinflammatory cytokine expression upon exposure to virus. Together, the findings concur that the hyperinflammation observed in SARS-CoV-2 infection is not driven by macrophages.


Subject(s)
Inflammation/virology , Macrophages/immunology , Macrophages/virology , SARS-CoV-2/immunology , Virus Replication/genetics , Cell Line , Cell Line, Tumor , Cells, Cultured , Cytokines/analysis , Cytokines/immunology , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H5N1 Subtype/genetics , Influenza A Virus, H5N1 Subtype/immunology , Interferon-alpha/pharmacology , Macrophages/drug effects , Male , SARS-CoV-2/genetics , SARS-CoV-2/physiology
3.
EBioMedicine ; 75: 103803, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1587923

ABSTRACT

BACKGROUND: The Coronavirus Disease 2019 (COVID-19) pandemic has been a great threat to global public health since 2020. Although the advance on vaccine development has been largely achieved, a strategy to alleviate immune overactivation in severe COVID-19 patients is still needed. The NLRP3 inflammasome is activated upon SARS-CoV-2 infection and associated with COVID-19 severity. However, the processes by which the NLRP3 inflammasome is involved in COVID-19 disease remain unclear. METHODS: We infected THP-1 derived macrophages, NLRP3 knockout mice, and human ACE2 transgenic mice with live SARS-CoV-2 in Biosafety Level 3 (BSL-3) laboratory. We performed quantitative real-time PCR for targeted viral or host genes from SARS-CoV-2 infected mouse tissues, conducted histological or immunofluorescence analysis in SARS-CoV-2 infected mouse tissues. We also injected intranasally AAV-hACE2 or intraperitoneally NLRP3 inflammasome inhibitor MCC950 before SARS-CoV-2 infection in mice as indicated. FINDINGS: We have provided multiple lines of evidence that the NLRP3 inflammasome plays an important role in the host immune response to SARS-CoV-2 invasion of the lungs. Inhibition of the NLRP3 inflammasome attenuated the release of COVID-19 related pro-inflammatory cytokines in cell cultures and mice. The severe pathology induced by SARS-CoV-2 in lung tissues was reduced in Nlrp3-/- mice compared to wild-type C57BL/6 mice. Finally, specific inhibition of the NLRP3 inflammasome by MCC950 alleviated excessive lung inflammation and thus COVID-19 like pathology in human ACE2 transgenic mice. INTERPRETATION: Inflammatory activation induced by SARS-CoV-2 is an important stimulator of COVID-19 related immunopathology. Targeting the NLRP3 inflammasome is a promising immune intervention against severe COVID-19 disease. FUNDING: This work was supported by grants from the Bureau of Frontier Sciences and Education, CAS (grant no. QYZDJ-SSW-SMC005 to Y.G.Y.), the key project of the CAS "Light of West China" Program (to D.Y.) and Yunnan Province (202001AS070023 to D.Y.).


Subject(s)
COVID-19 , Lung , Macrophages , NLR Family, Pyrin Domain-Containing 3 Protein/immunology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/immunology , Animals , COVID-19/genetics , COVID-19/immunology , COVID-19/pathology , Disease Models, Animal , Humans , Lung/immunology , Lung/pathology , Lung/virology , Macrophages/immunology , Macrophages/pathology , Macrophages/virology , Male , Mice , Mice, Knockout , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , SARS-CoV-2/genetics , THP-1 Cells
5.
Cell ; 184(26): 6243-6261.e27, 2021 12 22.
Article in English | MEDLINE | ID: covidwho-1536467

ABSTRACT

COVID-19-induced "acute respiratory distress syndrome" (ARDS) is associated with prolonged respiratory failure and high mortality, but the mechanistic basis of lung injury remains incompletely understood. Here, we analyze pulmonary immune responses and lung pathology in two cohorts of patients with COVID-19 ARDS using functional single-cell genomics, immunohistology, and electron microscopy. We describe an accumulation of CD163-expressing monocyte-derived macrophages that acquired a profibrotic transcriptional phenotype during COVID-19 ARDS. Gene set enrichment and computational data integration revealed a significant similarity between COVID-19-associated macrophages and profibrotic macrophage populations identified in idiopathic pulmonary fibrosis. COVID-19 ARDS was associated with clinical, radiographic, histopathological, and ultrastructural hallmarks of pulmonary fibrosis. Exposure of human monocytes to SARS-CoV-2, but not influenza A virus or viral RNA analogs, was sufficient to induce a similar profibrotic phenotype in vitro. In conclusion, we demonstrate that SARS-CoV-2 triggers profibrotic macrophage responses and pronounced fibroproliferative ARDS.


Subject(s)
COVID-19/pathology , COVID-19/virology , Idiopathic Pulmonary Fibrosis/pathology , Idiopathic Pulmonary Fibrosis/virology , Macrophages/pathology , Macrophages/virology , SARS-CoV-2/physiology , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , COVID-19/diagnostic imaging , Cell Communication , Cohort Studies , Fibroblasts/pathology , Gene Expression Regulation , Humans , Idiopathic Pulmonary Fibrosis/diagnostic imaging , Idiopathic Pulmonary Fibrosis/genetics , Mesenchymal Stem Cells/pathology , Phenotype , Proteome/metabolism , Receptors, Cell Surface/metabolism , Respiratory Distress Syndrome/diagnostic imaging , Respiratory Distress Syndrome/pathology , Respiratory Distress Syndrome/virology , Tomography, X-Ray Computed , Transcription, Genetic
6.
JCI Insight ; 6(22)2021 11 22.
Article in English | MEDLINE | ID: covidwho-1528615

ABSTRACT

BACKGROUNDInfluenza A virus (IAV) and SARS-CoV-2 are pandemic viruses causing millions of deaths, yet their clinical manifestations are distinctly different.METHODSWith the hypothesis that upper airway immune and epithelial cell responses are also distinct, we performed single-cell RNA sequencing (scRNA-Seq) on nasal wash cells freshly collected from adults with either acute COVID-19 or influenza or from healthy controls. We focused on major cell types and subtypes in a subset of donor samples.ResultsNasal wash cells were enriched for macrophages and neutrophils for both individuals with influenza and those with COVID-19 compared with healthy controls. Hillock-like epithelial cells, M2-like macrophages, and age-dependent B cells were enriched in COVID-19 samples. A global decrease in IFN-associated transcripts in neutrophils, macrophages, and epithelial cells was apparent in COVID-19 samples compared with influenza samples. The innate immune response to SARS-CoV-2 appears to be maintained in macrophages, despite evidence for limited epithelial cell immune sensing. Cell-to-cell interaction analyses revealed a decrease in epithelial cell interactions in COVID-19 and highlighted differences in macrophage-macrophage interactions for COVID-19 and influenza.ConclusionsOur study demonstrates that scRNA-Seq can define host and viral transcriptional activity at the site of infection and reveal distinct local epithelial and immune cell responses for COVID-19 and influenza that may contribute to their divergent disease courses.FundingMassachusetts Consortium on Pathogen Readiness, the Mathers Foundation, and the Department of Defense (W81XWH2110029) "COVID-19 Expansion for AIRe Program."


Subject(s)
COVID-19 , Immunity, Innate , Influenza A virus , Influenza, Human , Macrophages , RNA-Seq , SARS-CoV-2 , Adult , COVID-19/genetics , COVID-19/immunology , Female , Humans , Influenza A virus/genetics , Influenza A virus/immunology , Influenza, Human/genetics , Influenza, Human/immunology , Macrophages/immunology , Macrophages/virology , Male , Nasal Lavage , SARS-CoV-2/genetics , SARS-CoV-2/immunology
7.
Viruses ; 13(11)2021 10 28.
Article in English | MEDLINE | ID: covidwho-1488759

ABSTRACT

We aimed to explore whether variants of SARS-CoV-2 (Chinese-derived strain (D614, lineage A), Italian strain PV10734 (D614G, lineage B.1.1) and Alpha strain (lineage B.1.1.7)) were able to infect monocytes (MN) and monocyte-derived macrophages (MDM) and whether these infected cells may, in turn, be vectors of infection. For this purpose, we designed an in vitro study following the evolution of MN and MDM infection at different time points in order to confirm whether these cells were permissive for SARS-CoV-2 replication. Finally, we investigated whether, regardless of viral replication, the persistent virus can be transferred to non-infected cells permissive for viral replication. Thus, we co-cultured the infected MN/MDM with permissive VERO E6 cells verifying the viral transmission. This is a further in vitro demonstration of the important role of MN and MDM in the dissemination of SARS-CoV-2 and evolution of the COVID-19 disease.


Subject(s)
Macrophages/virology , Monocytes/virology , SARS-CoV-2/physiology , Animals , Chlorocebus aethiops , Coculture Techniques , Coronavirus Nucleocapsid Proteins/metabolism , Humans , Macrophages/ultrastructure , Monocytes/ultrastructure , Phosphoproteins/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Internalization , Virus Replication
8.
Arch Pathol Lab Med ; 145(11): 1328-1340, 2021 11 01.
Article in English | MEDLINE | ID: covidwho-1485410

ABSTRACT

CONTEXT.­: SARS-CoV-2 can undergo maternal-fetal transmission, heightening interest in the placental pathology findings from this infection. Transplacental SARS-CoV-2 transmission is typically accompanied by chronic histiocytic intervillositis together with necrosis and positivity of syncytiotrophoblast for SARS-CoV-2. Hofbauer cells are placental macrophages that have been involved in viral diseases, including HIV and Zika virus, but their involvement in SARS-CoV-2 is unknown. OBJECTIVE.­: To determine whether SARS-CoV-2 can extend beyond the syncytiotrophoblast to enter Hofbauer cells, endothelium, and other villous stromal cells in infected placentas of liveborn and stillborn infants. DESIGN.­: Case-based retrospective analysis by 29 perinatal and molecular pathology specialists of placental findings from a preselected cohort of 22 SARS-CoV-2-infected placentas delivered to pregnant women testing positive for SARS-CoV-2 from 7 countries. Molecular pathology methods were used to investigate viral involvement of Hofbauer cells, villous capillary endothelium, syncytiotrophoblast, and other fetal-derived cells. RESULTS.­: Chronic histiocytic intervillositis and trophoblast necrosis were present in all 22 placentas (100%). SARS-CoV-2 was identified in Hofbauer cells from 4 of 22 placentas (18.2%). Villous capillary endothelial staining was positive in 2 of 22 cases (9.1%), both of which also had viral positivity in Hofbauer cells. Syncytiotrophoblast staining occurred in 21 of 22 placentas (95.5%). Hofbauer cell hyperplasia was present in 3 of 22 placentas (13.6%). In the 7 cases having documented transplacental infection of the fetus, 2 (28.6%) occurred in placentas with Hofbauer cell staining positive for SARS-CoV-2. CONCLUSIONS.­: SARS-CoV-2 can extend beyond the trophoblast into the villous stroma, involving Hofbauer cells and capillary endothelial cells, in a small number of infected placentas. Most cases of SARS-CoV-2 transplacental fetal infection occur without Hofbauer cell involvement.


Subject(s)
COVID-19/transmission , COVID-19/virology , Infectious Disease Transmission, Vertical , Macrophages/virology , Placenta/virology , Pregnancy Complications, Infectious/virology , SARS-CoV-2/pathogenicity , Adult , COVID-19/immunology , COVID-19/pathology , Cell Proliferation , Endothelium/pathology , Endothelium/virology , Female , Humans , Hyperplasia/pathology , Hyperplasia/virology , Infant, Newborn , Macrophages/pathology , Macrophages/physiology , Male , Placenta/pathology , Pregnancy , Pregnancy Complications, Infectious/immunology , Pregnancy Complications, Infectious/pathology , Retrospective Studies , SARS-CoV-2/immunology , Stillbirth , Trophoblasts/pathology , Trophoblasts/virology
9.
Front Immunol ; 12: 741502, 2021.
Article in English | MEDLINE | ID: covidwho-1477825

ABSTRACT

Host innate immune response follows severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and it is the driver of the acute respiratory distress syndrome (ARDS) amongst other inflammatory end-organ morbidities. Such life-threatening coronavirus disease 2019 (COVID-19) is heralded by virus-induced activation of mononuclear phagocytes (MPs; monocytes, macrophages, and dendritic cells). MPs play substantial roles in aberrant immune secretory activities affecting profound systemic inflammation and end-organ malfunctions. All follow the presence of persistent viral components and virions without evidence of viral replication. To elucidate SARS-CoV-2-MP interactions we investigated transcriptomic and proteomic profiles of human monocyte-derived macrophages. While expression of the SARS-CoV-2 receptor, the angiotensin-converting enzyme 2, paralleled monocyte-macrophage differentiation, it failed to affect productive viral infection. In contrast, simple macrophage viral exposure led to robust pro-inflammatory cytokine and chemokine expression but attenuated type I interferon (IFN) activity. Both paralleled dysregulation of innate immune signaling pathways, specifically those linked to IFN. We conclude that the SARS-CoV-2-infected host mounts a robust innate immune response characterized by a pro-inflammatory storm heralding end-organ tissue damage.


Subject(s)
COVID-19/virology , Immunity, Innate , Macrophages/virology , SARS-CoV-2/pathogenicity , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/immunology , COVID-19/metabolism , Cells, Cultured , Cytokines/genetics , Cytokines/metabolism , Gene Expression Profiling , Gene Regulatory Networks , Host-Pathogen Interactions , Humans , Immunity, Innate/genetics , Inflammation Mediators/metabolism , Macrophages/immunology , Macrophages/metabolism , Proteome , Proteomics , Receptors, Virus/genetics , Receptors, Virus/metabolism , SARS-CoV-2/immunology , Signal Transduction , Transcriptome
10.
J Med Virol ; 93(9): 5350-5357, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1384240

ABSTRACT

PARP14 and PARP9 play a key role in macrophage immune regulation. SARS-CoV-2 is an emerging viral disease that triggers hyper-inflammation known as a cytokine storm. In this study, using in silico tools, we hypothesize about the immunological phenomena of molecular mimicry between SARS-CoV-2 Nsp3 and the human PARP14 and PARP9. The results showed an epitope of SARS-CoV-2 Nsp3 protein that contains consensus sequences for both human PARP14 and PARP9 that are antigens for MHC Classes 1 and 2, which can potentially induce an immune response against human PARP14 and PARP9; while its depletion causes a hyper-inflammatory state in SARS-CoV-2 patients.


Subject(s)
COVID-19/immunology , Coronavirus Papain-Like Proteases/chemistry , Cytokine Release Syndrome/immunology , Neoplasm Proteins/chemistry , Poly(ADP-ribose) Polymerases/chemistry , SARS-CoV-2/immunology , Amino Acid Sequence , Binding Sites , COVID-19/genetics , COVID-19/pathology , COVID-19/virology , Computer Simulation , Consensus Sequence , Coronavirus Papain-Like Proteases/genetics , Coronavirus Papain-Like Proteases/immunology , Cytokine Release Syndrome/genetics , Cytokine Release Syndrome/pathology , Cytokine Release Syndrome/virology , Epitopes/chemistry , Epitopes/genetics , Epitopes/immunology , Gene Expression , Histocompatibility Antigens Class I/chemistry , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/immunology , Histocompatibility Antigens Class II/chemistry , Histocompatibility Antigens Class II/genetics , Histocompatibility Antigens Class II/immunology , Host-Pathogen Interactions/genetics , Host-Pathogen Interactions/immunology , Humans , Macrophages/immunology , Macrophages/virology , Molecular Docking Simulation , Molecular Mimicry , Neoplasm Proteins/genetics , Neoplasm Proteins/immunology , Poly(ADP-ribose) Polymerases/genetics , Poly(ADP-ribose) Polymerases/immunology , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Sequence Alignment , Sequence Homology, Amino Acid , Thermodynamics
12.
FASEB J ; 35(9): e21801, 2021 09.
Article in English | MEDLINE | ID: covidwho-1345745

ABSTRACT

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a crucial role in mediating viral entry into host cells. However, whether it contributes to pulmonary hyperinflammation in patients with coronavirus disease 2019 is not well known. In this study, we developed a spike protein-pseudotyped (Spp) lentivirus with the proper tropism of the SARS-CoV-2 spike protein on the surface and determined the distribution of the Spp lentivirus in wild-type C57BL/6J male mice that received an intravenous injection of the virus. Lentiviruses with vesicular stomatitis virus glycoprotein (VSV-G) or with a deletion of the receptor-binding domain (RBD) in the spike protein [Spp (∆RBD)] were used as controls. Two hours postinfection (hpi), there were 27-75 times more viral burden from Spp lentivirus in the lungs than in other organs; there were also about 3-5 times more viral burden from Spp lentivirus than from VSV-G lentivirus in the lungs, liver, kidney, and spleen. Deletion of RBD diminished viral loads in the lungs but not in the heart. Acute pneumonia was observed in animals 24 hpi. Spp lentivirus was mainly found in SPC+ and LDLR+ pneumocytes and macrophages in the lungs. IL6, IL10, CD80, and PPAR-γ were quickly upregulated in response to infection in the lungs as well as in macrophage-like RAW264.7 cells. Furthermore, forced expression of the spike protein in RAW264.7 cells significantly increased the mRNA levels of the same panel of inflammatory factors. Our results demonstrated that the spike protein of SARS-CoV-2 confers the main point of viral entry into the lungs and can induce cellular pathology. Our data also indicate that an alternative ACE2-independent viral entry pathway may be recruited in the heart and aorta.


Subject(s)
Macrophages/immunology , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , Spike Glycoprotein, Coronavirus/immunology , Acute Disease , Alveolar Epithelial Cells/virology , Animals , B7-1 Antigen , Cell Line , Inflammation Mediators , Interleukin-10 , Interleukin-6 , Lentivirus/genetics , Lentivirus/isolation & purification , Lentivirus/metabolism , Lung/immunology , Lung/pathology , Lung/virology , Macrophages/virology , Male , Membrane Glycoproteins , Mice , Mice, Inbred C57BL , PPAR gamma , RAW 264.7 Cells , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Viral Envelope Proteins
13.
J Infect Dis ; 224(3): 395-406, 2021 08 02.
Article in English | MEDLINE | ID: covidwho-1338702

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) clinical expression is pleiomorphic, severity is related to age and comorbidities such as diabetes and hypertension, and pathophysiology involves aberrant immune activation and lymphopenia. We wondered if the myeloid compartment was affected during COVID-19 and if monocytes and macrophages could be infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: Monocytes and monocyte-derived macrophages (MDMs) from COVID-19 patients and controls were infected with SARS-CoV-2 and extensively investigated with immunofluorescence, viral RNA extraction and quantification, and total RNA extraction followed by reverse-transcription quantitative polymerase chain reaction using specific primers, supernatant cytokines (interleukins 6, 10, and 1ß; interferon-ß; transforming growth factor-ß1, and tumor necrosis factor-α), and flow cytometry. The effect of M1- vs M2-type or no polarization prior to infection was assessed. RESULTS: SARS-CoV-2 efficiently infected monocytes and MDMs, but their infection is abortive. Infection was associated with immunoregulatory cytokines secretion and the induction of a macrophagic specific transcriptional program characterized by the upregulation of M2-type molecules. In vitro polarization did not account for permissivity to SARS-CoV-2, since M1- and M2-type MDMs were similarly infected. In COVID-19 patients, monocytes exhibited lower counts affecting all subsets, decreased expression of HLA-DR, and increased expression of CD163, irrespective of severity. CONCLUSIONS: SARS-CoV-2 drives monocytes and macrophages to induce host immunoparalysis for the benefit of COVID-19 progression.SARS-CoV-2 infection of macrophages induces a specific M2 transcriptional program. In Covid-19 patients, monocyte subsets were decreased associated with up-expression of the immunoregulatory molecule CD163 suggesting that SARS-CoV-2 drives immune system for the benefit of Covid-19 disease progression.


Subject(s)
COVID-19/immunology , Macrophages/virology , Monocytes/virology , Respiratory Distress Syndrome/virology , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , Cytokines/metabolism , Female , Flow Cytometry , Fluorescent Antibody Technique , Humans , Male , Middle Aged , Respiratory Distress Syndrome/immunology , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/immunology , Severity of Illness Index , Young Adult
14.
Viral Immunol ; 34(9): 597-606, 2021 11.
Article in English | MEDLINE | ID: covidwho-1322606

ABSTRACT

Coronaviruses (CoVs) contribute significantly to the burden of respiratory diseases, frequently as upper respiratory tract infections. Recent emergence of novel coronaviruses in the last few decades has highlighted the potential transmission, disease, and mortality related to these viruses. In this literature review, we shall explore the disease-causing mechanism of the virus through human monocytes and macrophages. Common strains will be discussed; however, this review will center around coronaviruses responsible for epidemics, namely severe acute respiratory syndrome coronavirus (SARS-CoV)-1 and -2 and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV). Macrophages are key players in the immune system and have been found to play a role in the pathogenesis of lethal coronaviruses. In physiology, they are white blood cells that engulf and digest cellular debris, foreign substances, and microbes. They play a critical role in innate immunity and help initiate adaptive immunity. Human coronaviruses utilize various mechanisms to undermine the innate immune response through its interaction with macrophages and monocytes. It is capable of entering immune cells through DPP4 (dipeptidyl-peptidase 4) receptors and antibody-dependent enhancement, delaying initial interferon response which supports robust viral replication. Pathogenesis includes triggering the production of overwhelming pro-inflammatory cytokines that attract other immune cells to the site of infection, which propagate prolonged pro-inflammatory response. The virus has also been found to suppress the release of anti-inflammatory mediators such as IL-10, leading to an aberrant inflammatory response. Elevated serum cytokines are also believed to contribute to pathological features seen in severe disease such as coagulopathy, acute lung injury, and multiorgan failure.


Subject(s)
Coronavirus Infections/immunology , Coronavirus/immunology , Coronavirus/pathogenicity , Immunity, Innate , Macrophages/virology , Monocytes/virology , Animals , Coronavirus/classification , Coronavirus Infections/pathology , Coronavirus Infections/virology , Cytokines/blood , Cytokines/immunology , Humans , Inflammation/immunology , Inflammation/virology , Lung/pathology , Macrophages/immunology , Monocytes/immunology , Virus Replication
15.
Front Immunol ; 12: 683800, 2021.
Article in English | MEDLINE | ID: covidwho-1305645

ABSTRACT

The major cause of death in SARS-CoV-2 infected patients is due to de-regulation of the innate immune system and development of cytokine storm. SARS-CoV-2 infects multiple cell types in the lung, including macrophages, by engagement of its spike (S) protein on angiotensin converting enzyme 2 (ACE2) receptor. ACE2 receptor initiates signals in macrophages that modulate their activation, including production of cytokines and chemokines. IL-1R-associated kinase (IRAK)-M is a central regulator of inflammatory responses regulating the magnitude of TLR responsiveness. Aim of the work was to investigate whether SARS-CoV-2 S protein-initiated signals modulate pro-inflammatory cytokine production in macrophages. For this purpose, we treated PMA-differentiated THP-1 human macrophages with SARS-CoV-2 S protein and measured the induction of inflammatory mediators including IL6, TNFα, IL8, CXCL5, and MIP1a. The results showed that SARS-CoV-2 S protein induced IL6, MIP1a and TNFα mRNA expression, while it had no effect on IL8 and CXCL5 mRNA levels. We further examined whether SARS-CoV-2 S protein altered the responsiveness of macrophages to TLR signals. Treatment of LPS-activated macrophages with SARS-CoV-2 S protein augmented IL6 and MIP1a mRNA, an effect that was evident at the protein level only for IL6. Similarly, treatment of PAM3csk4 stimulated macrophages with SARS-CoV-2 S protein resulted in increased mRNA of IL6, while TNFα and MIP1a were unaffected. The results were confirmed in primary human peripheral monocytic cells (PBMCs) and isolated CD14+ monocytes. Macrophage responsiveness to TLR ligands is regulated by IRAK-M, an inactive IRAK kinase isoform. Indeed, we found that SARS-CoV-2 S protein suppressed IRAK-M mRNA and protein expression both in THP1 macrophages and primary human PBMCs and CD14+ monocytes. Engagement of SARS-CoV-2 S protein with ACE2 results in internalization of ACE2 and suppression of its activity. Activation of ACE2 has been previously shown to induce anti-inflammatory responses in macrophages. Treatment of macrophages with the ACE2 activator DIZE suppressed the pro-inflammatory action of SARS-CoV-2. Our results demonstrated that SARS-CoV-2/ACE2 interaction rendered macrophages hyper-responsive to TLR signals, suppressed IRAK-M and promoted pro-inflammatory cytokine expression. Thus, activation of ACE2 may be a potential anti-inflammatory therapeutic strategy to eliminate the development of cytokine storm observed in COVID-19 patients.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/immunology , Cytokine Release Syndrome/immunology , Interleukin-1 Receptor-Associated Kinases/metabolism , Macrophages/immunology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Gene Expression Regulation , Humans , Immunity, Innate , Inflammation Mediators/metabolism , Interleukin-1 Receptor-Associated Kinases/genetics , Interleukin-6/genetics , Interleukin-6/metabolism , Lipopolysaccharides/immunology , Macrophages/virology , Protein Binding , THP-1 Cells , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism
16.
J Virol ; 95(15): e0076621, 2021 07 12.
Article in English | MEDLINE | ID: covidwho-1305511

ABSTRACT

All coronaviruses (CoVs) contain a macrodomain, also termed Mac1, in nonstructural protein 3 (nsp3) that binds and hydrolyzes mono-ADP-ribose (MAR) covalently attached to proteins. Despite several reports demonstrating that Mac1 is a prominent virulence factor, there is still a limited understanding of its cellular roles during infection. Currently, most of the information regarding the role of CoV Mac1 during infection is based on a single point mutation of a highly conserved asparagine residue, which makes contact with the distal ribose of ADP-ribose. To determine if additional Mac1 activities contribute to CoV replication, we compared the replication of murine hepatitis virus (MHV) Mac1 mutants, D1329A and N1465A, to the previously mentioned asparagine mutant, N1347A. These residues contact the adenine and proximal ribose in ADP-ribose, respectively. N1465A had no effect on MHV replication or pathogenesis, while D1329A and N1347A both replicated poorly in bone marrow-derived macrophages (BMDMs), were inhibited by PARP enzymes, and were highly attenuated in vivo. Interestingly, D1329A was also significantly more attenuated than N1347A in all cell lines tested. Conversely, D1329A retained some ability to block beta interferon (IFN-ß) transcript accumulation compared to N1347A, indicating that these mutations have different effects on Mac1 functions. Combining these two mutations resulted in a virus that was unrecoverable, suggesting that the combined activities of Mac1 are essential for MHV replication. We conclude that Mac1 has multiple functions that promote the replication of MHV, and that these results provide further evidence that Mac1 is a prominent target for anti-CoV therapeutics. IMPORTANCE In the wake of the COVID-19 epidemic, there has been a surge to better understand how CoVs replicate and to identify potential therapeutic targets that could mitigate disease caused by SARS-CoV-2 and other prominent CoVs. The highly conserved macrodomain, also termed Mac1, is a small domain within nonstructural protein 3. It has received significant attention as a potential drug target, as previous studies demonstrated that it is essential for CoV pathogenesis in multiple animal models of infection. However, the functions of Mac1 during infection remain largely unknown. Here, using targeted mutations in different regions of Mac1, we found that Mac1 has multiple functions that promote the replication of MHV, a model CoV, and, therefore, is more important for MHV replication than previously appreciated. These results will help guide the discovery of these novel functions of Mac1 and the development of inhibitory compounds targeting this domain.


Subject(s)
Murine hepatitis virus/physiology , Mutation, Missense , Viral Nonstructural Proteins , Virus Replication/genetics , Amino Acid Substitution , Animals , HeLa Cells , Humans , Macrophages/metabolism , Macrophages/virology , Mice , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism
17.
Cardiovasc Pathol ; 54: 107361, 2021.
Article in English | MEDLINE | ID: covidwho-1281392

ABSTRACT

COVID-19 has a significant effect upon the cardiovascular system. While a number of different cardiovascular histopathologies have been described at post-mortem examination, the incidence of typical viral myocarditis in COVID-19 positive patients appears very low [1-3]. In this study, we further characterize and quantify the inflammatory cell infiltrate in a COVID-19 study cohort and compare the findings to both an age and disease matched control cohort and a cohort of patients diagnosed with typical inflammatory myocarditis. All study and control cohorts had 1 or more of the comorbidities most commonly associated with severe disease (hypertension, type II diabetes, obesity, or known cardiovascular disease). The results demonstrate a skewed distribution of the number of CD68+ cells in COVID-19 hearts, with upper quantiles showing a significant increase as compared to both matched control hearts, and those with myocarditis. In contrast, hearts from typical inflammatory myocarditis contained increased numbers of CD4+, and CD8+ cells compared to both COVID-19 and control cohorts. In conclusion, the presence of an increased number of CD68+ cells suggests that COVID-19 may incite a form of myocarditis different from typical viral myocarditis, and associated with diffusely infiltrative cells of monocytes/macrophage lineage.


Subject(s)
Antigens, CD/analysis , Antigens, Differentiation, Myelomonocytic/analysis , COVID-19/immunology , Macrophages/immunology , Myocarditis/immunology , Myocardium/immunology , Adult , Aged , Autopsy , Biomarkers/analysis , COVID-19/mortality , COVID-19/pathology , COVID-19/virology , Case-Control Studies , Female , Host-Pathogen Interactions , Humans , Immunohistochemistry , Macrophages/virology , Male , Middle Aged , Myocarditis/mortality , Myocarditis/pathology , Myocarditis/virology , Myocardium/pathology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity
18.
Theranostics ; 11(15): 7379-7390, 2021.
Article in English | MEDLINE | ID: covidwho-1266907

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a novel strain of highly contagious coronaviruses that infects humans. Prolonged fever, particularly that above 39.5 °C, is associated with SARS-CoV-2 infection. However, little is known about the pathological effects of fever caused by SARS-CoV-2. Methods: Primary bovine alveolar macrophages (PBAMs), RAW264.7 mouse macrophages, and THP-1 human cells were transfected with plasmids carrying the genes encoding the SARS-CoV-2 spike (S) protein or receptor-binding domain (RBD). Proteins in the macrophages interacting with S-RBD at 39.5 °C or 37 °C were identified by immunoprecipitation-mass spectrometry. Glutathione S-transferase pulldown, surface plasmon resonance, and immunofluorescence were performed to evaluate the transient receptor potential vanilloid 2 (TRPV2) interaction with SARS-CoV-2-S-RBD at 39.5 °C. Using an RNA sequencing-based approach, cytokine gene expression induced by SARS-CoV-2 S transfection at 39.5 °C and 37.5 °C in primary alveolar macrophages was measured. Fluo-4 staining and enzyme-linked immunosorbent assays were used to assess the regulatory function of TRPV2 in intracellular Ca 2+ and cytokines under SARS-CoV-2-S-RBD at 39.5 °C. Additionally, cytokine release was examined after TRPV2 knockdown with shRNA oligonucleotides or inhibition using the SKF-96365 antagonist. Results: We identified an interaction between the primary alveolar macrophage receptor TRPV2 and S-RBD under febrile conditions. Febrile temperature promotes Ca2+ influx through SARS-CoV-2 infection in PBAMs, further activates the NF-κB p65 signaling pathway, and enhances the secretion of cytokines. Furthermore, knockdown or antagonist (with SKF-96365) of TRPV2 significantly decreased the release of cytokines that drive the inflammatory response. Conclusion: Collectively, our findings identified TRPV2 as a receptor of SARS-CoV-2 in conditions of febrile temperature, providing insight into critical interactions of SARS-CoV-2 with macrophages, as well as a useful resource and potential drug target for coronavirus disease 2019.


Subject(s)
COVID-19/virology , Fever/virology , Macrophages/metabolism , Macrophages/virology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , TRPV Cation Channels/metabolism , Virus Internalization , Animals , Calcium/metabolism , Cattle , Cells, Cultured , Cytokines/metabolism , Humans , Imidazoles/pharmacology , Kinetics , Macrophages/drug effects , Mice , NF-kappa B/metabolism , Protein Binding/drug effects , RAW 264.7 Cells , SARS-CoV-2/drug effects , Signal Transduction/drug effects , THP-1 Cells , Temperature , Virus Internalization/drug effects
19.
Blood ; 138(4): 344-349, 2021 07 29.
Article in English | MEDLINE | ID: covidwho-1255893

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with the hypercoagulable state. Tissue factor (TF) is the primary cellular initiator of coagulation. Most of the TF expressed on cell surfaces remains cryptic. Sphingomyelin (SM) is responsible for maintaining TF in the encrypted state, and hydrolysis of SM by acid sphingomyelinase (ASMase) increases TF activity. ASMase was shown to play a role in virus infection biology. In the present study, we investigated the role of ASMase in SARS-CoV-2 infection-induced TF procoagulant activity. Infection of human monocyte-derived macrophages (MDMs) with SARS-CoV-2 spike protein pseudovirus (SARS-CoV-2-SP-PV) markedly increased TF procoagulant activity at the cell surface and released TF+ extracellular vesicles. The pseudovirus infection did not increase either TF protein expression or phosphatidylserine externalization. SARS-CoV-2-SP-PV infection induced the translocation of ASMase to the outer leaflet of the plasma membrane, which led to the hydrolysis of SM in the membrane. Pharmacologic inhibitors or genetic silencing of ASMase attenuated SARS-CoV-2-SP-PV-induced increased TF activity. Inhibition of the SARS-CoV-2 receptor, angiotensin-converting enzyme-2, attenuated SARS-CoV-2-SP-PV-induced increased TF activity. Overall, our data suggest that SARS-CoV-2 infection activates the coagulation by decrypting TF through activation of ASMase. Our data suggest that the US Food and Drug Administration-approved functional inhibitors of ASMase may help treat hypercoagulability in patients with COVID-19.


Subject(s)
COVID-19/blood , Macrophages/virology , Membrane Proteins/physiology , SARS-CoV-2 , Sphingomyelin Phosphodiesterase/physiology , Spike Glycoprotein, Coronavirus/physiology , Thrombophilia/etiology , Thromboplastin/physiology , Angiotensin-Converting Enzyme 2/physiology , COVID-19/complications , Cell-Derived Microparticles , Enzyme Activation , Humans , Hydrolysis , Macrophages/enzymology , Molecular Targeted Therapy , Plasmids , Protein Transport , RNA Interference , RNA, Small Interfering/genetics , Receptors, Virus/physiology , Sphingomyelin Phosphodiesterase/antagonists & inhibitors , Sphingomyelins/physiology , Thrombophilia/blood , Thrombophilia/drug therapy , Thrombophilia/enzymology
20.
Genes (Basel) ; 12(6)2021 05 24.
Article in English | MEDLINE | ID: covidwho-1243973

ABSTRACT

The current SARS-CoV-2 pandemic is still threatening humankind. Despite first successes in vaccine development and approval, no antiviral treatment is available for COVID-19 patients. The success is further tarnished by the emergence and spreading of mutation variants of SARS-CoV-2, for which some vaccines have lower efficacy. This highlights the urgent need for antiviral therapies even more. This article describes how the genome-scale metabolic model (GEM) of the host-virus interaction of human alveolar macrophages and SARS-CoV-2 was refined by incorporating the latest information about the virus's structural proteins and the mutant variants B.1.1.7, B.1.351, B.1.28, B.1.427/B.1.429, and B.1.617. We confirmed the initially identified guanylate kinase as a potential antiviral target with this refined model and identified further potential targets from the purine and pyrimidine metabolism. The model was further extended by incorporating the virus' lipid requirements. This opened new perspectives for potential antiviral targets in the altered lipid metabolism. Especially the phosphatidylcholine biosynthesis seems to play a pivotal role in viral replication. The guanylate kinase is even a robust target in all investigated mutation variants currently spreading worldwide. These new insights can guide laboratory experiments for the validation of identified potential antiviral targets. Only the combination of vaccines and antiviral therapies will effectively defeat this ongoing pandemic.


Subject(s)
COVID-19/metabolism , COVID-19/virology , Energy Metabolism , Genome, Viral , Guanylate Kinases/metabolism , Host-Pathogen Interactions , Mutation , SARS-CoV-2/genetics , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , COVID-19/genetics , Gene Knockdown Techniques , Humans , Lipid Metabolism , Macrophages/immunology , Macrophages/metabolism , Macrophages/virology , SARS-CoV-2/drug effects , Viral Load , Virus Replication
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