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1.
Front Immunol ; 12: 635942, 2021.
Article in English | MEDLINE | ID: covidwho-1389176

ABSTRACT

SARS-CoV-2 infection takes a mild or clinically inapparent course in the majority of humans who contract this virus. After such individuals have cleared the virus, only the detection of SARS-CoV-2-specific immunological memory can reveal the exposure, and hopefully the establishment of immune protection. With most viral infections, the presence of specific serum antibodies has provided a reliable biomarker for the exposure to the virus of interest. SARS-CoV-2 infection, however, does not reliably induce a durable antibody response, especially in sub-clinically infected individuals. Consequently, it is plausible for a recently infected individual to yield a false negative result within only a few months after exposure. Immunodiagnostic attention has therefore shifted to studies of specific T cell memory to SARS-CoV-2. Most reports published so far agree that a T cell response is engaged during SARS-CoV-2 infection, but they also state that in 20-81% of SARS-CoV-2-unexposed individuals, T cells respond to SARS-CoV-2 antigens (mega peptide pools), allegedly due to T cell cross-reactivity with Common Cold coronaviruses (CCC), or other antigens. Here we show that, by introducing irrelevant mega peptide pools as negative controls to account for chance cross-reactivity, and by establishing the antigen dose-response characteristic of the T cells, one can clearly discern between cognate T cell memory induced by SARS-CoV-2 infection vs. cross-reactive T cell responses in individuals who have not been infected with SARS-CoV-2.


Subject(s)
COVID-19/immunology , COVID-19/virology , Host-Pathogen Interactions/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Antigens, Viral/immunology , Biomarkers , COVID-19/metabolism , Cross Reactions/immunology , Cytokines/metabolism , Epitopes, T-Lymphocyte/immunology , Humans , Immunodominant Epitopes/immunology , Immunologic Memory , Peptides/immunology , Protein Binding , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes/metabolism
2.
Viral Immunol ; 34(5): 352-357, 2021 06.
Article in English | MEDLINE | ID: covidwho-1343610

ABSTRACT

Intense immunological dysregulation including immune cell lesions has been characteristically observed in severe cases of coronavirus disease-2019 (COVID-19), for which molecular mechanisms are not properly understood. A study of physiological expressions of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) host cell entry-related factors in immune system components may help explain molecular mechanisms involved in COVID-19 immunopathology. We analyzed transcriptomic and proteomic expression metadata for SARS-CoV-2 host cell entry receptor ACE2 and entry associated proteases (TMPRSS2, CTSL, and FURIN) in silico across immune system components including the blood lineage cells. ACE2 was not detected in any of the studied immune cell components; however, varying transcriptomic and proteomic expressions were observed for TMPRSS2, CTSL, and FURIN. Nondetectable expressions of SARS-CoV-2 host cell entry receptor ACE2 in immune system components or blood lineage cells indicate it does not mediate immune cell lesions in COVID-19. Alternative mechanisms need to be explored for COVID-19 immunopathogenesis.


Subject(s)
COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/immunology , Virus Internalization , Angiotensin-Converting Enzyme 2/genetics , Cathepsin L/genetics , Furin/genetics , Healthy Volunteers , Humans , Immune System , Metadata , Proteomics , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Serine Endopeptidases/genetics , Transcriptome
3.
Cell Discov ; 7(1): 38, 2021 May 25.
Article in English | MEDLINE | ID: covidwho-1243287

ABSTRACT

The newly emerging coronavirus SARS-CoV-2 causes severe lung disease and substantial mortality. How the virus evades host defense for efficient replication is not fully understood. In this report, we found that the SARS-CoV-2 nucleocapsid protein (NP) impaired stress granule (SG) formation induced by viral RNA. SARS-CoV-2 NP associated with the protein kinase PKR after dsRNA stimulation. SARS-CoV-2 NP did not affect dsRNA-induced PKR oligomerization, but impaired dsRNA-induced PKR phosphorylation (a hallmark of its activation) as well as SG formation. SARS-CoV-2 NP also targeted the SG-nucleating protein G3BP1 and impaired G3BP1-mediated SG formation. Deficiency of PKR or G3BP1 impaired dsRNA-triggered SG formation and increased SARS-CoV-2 replication. The NP of SARS-CoV also targeted both PKR and G3BP1 to impair dsRNA-induced SG formation, whereas the NP of MERS-CoV targeted PKR, but not G3BP1 for the impairment. Our findings suggest that SARS-CoV-2 NP promotes viral replication by impairing formation of antiviral SGs, and reveal a conserved mechanism on evasion of host antiviral responses by highly pathogenic human betacoronaviruses.

4.
Hepat Med ; 13: 37-44, 2021.
Article in English | MEDLINE | ID: covidwho-1197452

ABSTRACT

BACKGROUND: The SARS-CoV-2 virus may have direct or indirect effects on other human organs beyond the respiratory system and including the liver, via binding of the spike protein. This study investigated the potential direct interactions with the liver by comparing the binding of SARS-CoV-2 spike proteins to human AT2-like cells, primary human hepatocytes and immortalized hepatocyte-like hybrid cells. Receptors with binding specificity for SARS-CoV-2 spike protein on AT2 cells and hepatocytes were identified. METHODS: The specific binding of biotinylated spike and spike 1 proteins to undifferentiated human E12 MLPC (E12), E12 differentiated alveolar type 2 (AT2) cells, primary human hepatocytes (PHH) and E12 human hepatocyte-like hybrid cells (HLC) was studied by confocal microscopy. We investigated the expression of ACE-2, binding of biotinylated spike protein, biotinylated spike 1 and inhibition of binding by unlabeled spike protein, two neutralizing antibodies and an antibody directed against the hepatocyte asialoglycoprotein receptor 1 (ASGr1). RESULTS: E12 MLPC did not express ACE-2 and did not bind either of spike or spike 1 proteins. AT2-like cells expressed ACE-2 and bound both spike and spike 1. Both PHH and HLC did not express ACE-2 and did not bind spike 1 protein. However, both PHH and HLC actively bound the spike protein. Biotinylated spike protein binding was inhibited by unlabeled spike but not spike 1 protein on PHH and HLC. Two commercial neutralizing antibodies blocked the binding of the spike to PHH and HLC but only one blocked binding to AT2. An antibody to the hepatocyte ASGr1 blocked the binding of the spike protein to PHH and HLC. CONCLUSION: The absence of ACE-2 receptors and inhibition of spike binding by an antibody to the ASGr1 on both PHH and HLC suggested that the spike protein interacts with the ASGr1. The differential antibody blocking of spike binding to AT2, PHH and HLC indicated that neutralizing activity of SARS-CoV-2 binding might involve additional mechanisms beyond RBD binding to ACE-2.

5.
Int J Environ Res Public Health ; 18(8)2021 04 08.
Article in English | MEDLINE | ID: covidwho-1178247

ABSTRACT

Since December 2019, coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread, becoming the first pandemic of the 21st century by number of deaths (over 2,000,000 worldwide). Many aspects of SARS-CoV-2 infection in children and adolescents remain unclear, and optimal treatment has not yet been defined. Therefore, our goal was to develop a consensus document, practically synthesizing the accumulated data and clinical experience of our expert group. Literature research was carried out using the keywords "COVID-19" or "SARS-CoV-2" and "children" or "pediatrics" and "prevention" or "diagnosis" or "MIS-C" or "treatment" in electronic databases (MEDLINE, PUBMED), existing guidelines and gray literature. The fact that the majority of the problems posed by SARS-CoV-2 infection in pediatric age do not need hospital care and that, therefore, infected children and adolescents can be managed at home highlights the need for a strengthening of territorial pediatric structures. The sharing of hospitalization and therapeutic management criteria for severe cases between professionals is essential to ensure a fair approach based on the best available knowledge. Moreover, the activity of social and health professionals must also include the description, management and limitation of psychophysical-relational damage resulting from the SARS-CoV-2 pandemic on the health of children and adolescents, whether or not affected by COVID-19. Due to the characteristics of COVID-19 pathology in pediatric age, the importance of strengthening the network between hospital and territorial pediatrics, school, educational, social and family personnel both for strictly clinical management and for the reduction in discomfort, with priority in children of more frail families, represents a priority.


Subject(s)
COVID-19 , Pediatrics , Adolescent , Child , Consensus , Humans , Italy/epidemiology , SARS-CoV-2
6.
iScience ; 24(3): 102254, 2021 Mar 19.
Article in English | MEDLINE | ID: covidwho-1122297

ABSTRACT

Epidemiological data showing increased severity and mortality of COVID-19 in men suggests a potential role for androgen in SARS-CoV-2 infection. Here, we present evidence for the transcriptional regulation of SARS-CoV-2 host cell receptor ACE2 and TMPRSS2 by androgen in mouse and human cells. Additionally, we demonstrate the endogenous interaction between TMPRSS2 and ACE2 in human cells and validate ACE2 as a TMPRSS2 substrate. Furthermore, camostat-a TMPRSS2 inhibitor-blocked the cleavage of pseudotype SARS-CoV-2 surface Spike without disrupting TMPRSS2-ACE2 interaction, thus providing evidence for the first time of a direct role of TMPRSS2 in priming the SARS-CoV-2 Spike, required for viral fusion to the host cell. Importantly, androgen-deprivation, anti-androgens, or camostat attenuated the SARS-CoV-2 S-mediated cellular entry. Together, our data provide a strong rationale for clinical evaluations of TMPRSS2 inhibitors and androgen-deprivation therapy/androgen receptor antagonists alone or in combination with antiviral drugs as early as clinically possible to prevent COVID-19 progression.

7.
Am J Physiol Lung Cell Mol Physiol ; 320(2): L246-L253, 2021 02 01.
Article in English | MEDLINE | ID: covidwho-1088311

ABSTRACT

The COVID-19 pandemic is an ongoing threat to public health. Since the identification of COVID-19, the disease caused by SARS-CoV-2, no drugs have been developed to specifically target SARS-CoV-2. To develop effective and safe treatment options, a better understanding of cellular mechanisms underlying SARS-CoV-2 infection is required. To fill this knowledge gap, researchers require reliable experimental systems that express the host factor proteins necessary for the cellular entry of SARS-CoV-2. These proteins include the viral receptor, angiotensin-converting enzyme 2 (ACE2), and the proteases, transmembrane serine protease 2 (TMPRSS2) and furin. A number of studies have reported cell-type-specific expression of the genes encoding these molecules. However, less is known about the protein expression of these molecules. We assessed the suitability of primary human bronchial epithelial (HBE) cells maintained in an air-liquid interface (ALI) as an experimental system for studying SARS-CoV-2 infection in vitro. During cellular differentiation, we measured the expression of ACE2, TMPRSS2, and furin over progressive ALI days by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot, and immunofluorescence staining. We also explored the effect of the fibrotic cytokine TGF-ß on the expression of these proteins in well-differentiated HBE cells. Like ACE2, TMPRSS2 and furin proteins are localized in differentiated ciliated cells, as confirmed by immunofluorescence staining. These data suggest that well-differentiated HBE cells maintained in ALI are a reliable in vitro system for investigating cellular mechanisms of SARS-CoV-2 infection. We further identified that the profibrotic mediators, TGF-ß1 and TGF-ß2, increase the expression of furin, which is a protease required for the cellular entry of SARS-CoV-2.


Subject(s)
Bronchi/metabolism , COVID-19/etiology , Furin/metabolism , SARS-CoV-2 , Transforming Growth Factor beta1/metabolism , Transforming Growth Factor beta2/metabolism , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Bronchi/cytology , Bronchi/drug effects , Cell Differentiation , Cells, Cultured , Disease Susceptibility , Epithelial Cells/cytology , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Furin/genetics , Gene Expression/drug effects , Host Microbial Interactions/drug effects , Host Microbial Interactions/genetics , Host Microbial Interactions/physiology , Humans , Models, Biological , Pandemics , RNA, Messenger/genetics , RNA, Messenger/metabolism , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Transforming Growth Factor beta1/pharmacology , Transforming Growth Factor beta2/pharmacology , Virus Internalization
8.
FASEB J ; 35(3): e21419, 2021 03.
Article in English | MEDLINE | ID: covidwho-1075599

ABSTRACT

In the early phase of the Coronavirus disease 2019 (COVID-19) pandemic, it was postulated that the renin-angiotensin-system inhibitors (RASi) increase the infection risk. This was primarily based on numerous reports, which stated that the RASi could increase the organ Angiotensin-converting enzyme 2 (ACE2), the receptor of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in rodents. RASi can theoretically antagonize the potential influence of angiotensin II (Ang II) on ACE2. However, while Ang II decreases the ACE2 levels in cultured cells, there is little evidence that supports this phenomenon in living animals. In this study, we tested whether Ang II or Ang II combined with its antagonist would alter the ACE2 and other molecules associated with the infection of SARS-CoV-2. Male C57BL6/J mice were administered vehicle, Ang II (400 ng/kg/min), or Ang II with losartan (10 mg/kg/min) for 2 weeks. ACE2 knockout mice were used as a negative control for the ACE2 assay. We found that both Ang II, which elevated blood pressure by 30 mm Hg, and Ang II with losartan, had no effect on the expression or protein activity of ACE2 in the lung, left ventricle, kidney, and ileum. Likewise, these interventions had no effect on the expression of Transmembrane Protease Serine 2 (TMPRSS2) and Furin, proteases that facilitate the virus-cell fusion, and the expression or activity of Tumor Necrosis Factor α-Convertase (TACE) that cleaves cell-surface ACE2. Collectively, physiological concentrations of Ang II do not modulate the molecules associated with SARS-CoV-2 infection. These results support the recent observational studies suggesting that the use of RASi is not a risk factor for COVID-19.


Subject(s)
Angiotensin II Type 1 Receptor Blockers/pharmacology , Angiotensin II/pharmacology , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Losartan/pharmacology , SARS-CoV-2 , ADAM17 Protein/genetics , ADAM17 Protein/metabolism , Angiotensin II/administration & dosage , Angiotensin II Type 1 Receptor Blockers/administration & dosage , Angiotensin-Converting Enzyme 2/genetics , Animals , Furin/genetics , Furin/metabolism , Gene Expression Regulation, Enzymologic/drug effects , Losartan/administration & dosage , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Vasoconstrictor Agents/pharmacology
9.
Nat Commun ; 12(1): 972, 2021 02 09.
Article in English | MEDLINE | ID: covidwho-1075220

ABSTRACT

Among the many questions unanswered for the COVID-19 pandemic are the origin of SARS-CoV-2 and the potential role of intermediate animal host(s) in the early animal-to-human transmission. The discovery of RaTG13 bat coronavirus in China suggested a high probability of a bat origin. Here we report molecular and serological evidence of SARS-CoV-2 related coronaviruses (SC2r-CoVs) actively circulating in bats in Southeast Asia. Whole genome sequences were obtained from five independent bats (Rhinolophus acuminatus) in a Thai cave yielding a single isolate (named RacCS203) which is most related to the RmYN02 isolate found in Rhinolophus malayanus in Yunnan, China. SARS-CoV-2 neutralizing antibodies were also detected in bats of the same colony and in a pangolin at a wildlife checkpoint in Southern Thailand. Antisera raised against the receptor binding domain (RBD) of RmYN02 was able to cross-neutralize SARS-CoV-2 despite the fact that the RBD of RacCS203 or RmYN02 failed to bind ACE2. Although the origin of the virus remains unresolved, our study extended the geographic distribution of genetically diverse SC2r-CoVs from Japan and China to Thailand over a 4800-km range. Cross-border surveillance is urgently needed to find the immediate progenitor virus of SARS-CoV-2.


Subject(s)
Chiroptera/virology , Pangolins/virology , SARS-CoV-2/physiology , Amino Acid Sequence , Animals , Antibodies, Neutralizing/blood , Asia, Southeastern , COVID-19/virology , Chiroptera/blood , Geography , Neutralization Tests , Phylogeny , Protein Domains , Receptors, Cell Surface/chemistry , Receptors, Cell Surface/metabolism
10.
Sci Total Environ ; 774: 145732, 2021 Jun 20.
Article in English | MEDLINE | ID: covidwho-1071919

ABSTRACT

Current wastewater worker guidance from the United States Environmental Protection Agency (USEPA) aligns with the Centers for Disease Control and Prevention (CDC) and the Occupational Safety and Health Administration (OSHA) recommendations and states that no additional specific protections against SARS-CoV-2, the virus that causes COVID-19 infections, are recommended for employees involved in wastewater management operations with residuals, sludge, and biosolids at water resource recovery facilities. The USEPA guidance references a document from 2002 that summarizes practices required for protection of workers handling class B biosolids to minimize exposure to pathogens including viruses. While there is no documented evidence that residuals or biosolids of any treatment level contain infectious SARS-CoV-2 or are a source of transmission of this current pandemic strain of coronavirus, this review summarizes and examines whether the provided federal guidance is sufficient to protect workers in view of currently available data on SARS-CoV-2 persistence and transmission. No currently available epidemiological data establishes a direct link between wastewater sludge or biosolids and risk of infection from the SARS-CoV-2. Despite shedding of the RNA of the virus in feces, there is no evidence supporting the presence or transmission of infectious SARS-CoV-2 through the wastewater system or in biosolids. In addition, this review presents previous epidemiologic data related to other non-enveloped viruses. Overall, the risk for exposure to SARS-CoV-2, or any pathogen, decreases with increasing treatment measures. As a result, the highest risk of exposure is related to spreading and handling untreated feces or stool, followed by untreated municipal sludge, the class B biosolids, while lowest risk is associated with spreading or handling Class A biosolids. This review reinforces federal recommendations and the importance of vigilance in applying occupational risk mitigation measures to protect public and occupational health.


Subject(s)
COVID-19 , Occupational Health , Biosolids , Humans , Pandemics , SARS-CoV-2 , United States
11.
ACS Cent Sci ; 7(1): 164-174, 2021 Jan 27.
Article in English | MEDLINE | ID: covidwho-1052088

ABSTRACT

Recent efforts to repurpose drugs to combat COVID-19 have identified Remdesivir as a candidate. It acts on the RNA-dependent, RNA polymerase (RdRp) of the SARS-CoV-2 virus, a protein complex responsible for mediating replication of the virus's genome. However, its exact action mechanism, and that of other nucleotide analogue inhibitors, is not known. In this study, we examine at the molecular level the interaction of this drug and that of similar nucleotide analogue inhibitors, ribavirin and favilavir, by relying on atomistic molecular simulations and advanced sampling. By analyzing the binding free energies of these different drugs, it is found that all of them bind strongly at the active site. Surprisingly, however, ribavirin and favilavir do not bind the nucleotide on the complementary strand as effectively and seem to act by a different mechanism than remdesivir. Remdesivir exhibits similar binding interactions to the natural base adenine. Moreover, by analyzing remdesivir at downstream positions of the RNA, we also find that, consistent with a "delayed" termination mechanism, additional nucleotides can be incorporated after remdesivir is added, and its highly polar 1'-cyano group induces a set of conformational changes that can affect the normal RdRp complex function. By analyzing the fluctuations of residues that are altered by remdesivir binding, and comparing them to those induced by lethal point mutations, we find a possible secondary mechanism in which remdesivir destabilizes the protein complex and its interactions with the RNA strands.

12.
Sci Rep ; 11(1): 413, 2021 01 11.
Article in English | MEDLINE | ID: covidwho-1019887

ABSTRACT

The spike protein of SARS-CoV-2 is known to enable viral invasion into human cells through direct binding to host receptors including ACE2. An alternate entry receptor for the virus was recently proposed to be basigin/CD147. These early studies have already prompted a clinical trial and multiple published hypotheses speculating on the role of this host receptor in viral infection and pathogenesis. Here, we report that we are unable to find evidence supporting the role of basigin as a putative spike binding receptor. Recombinant forms of the SARS-CoV-2 spike do not interact with basigin expressed on the surface of human cells, and by using specialized assays tailored to detect receptor interactions as weak or weaker than the proposed basigin-spike binding, we report no evidence for a direct interaction between the viral spike protein to either of the two common isoforms of basigin. Finally, removing basigin from the surface of human lung epithelial cells by CRISPR/Cas9 results in no change in their susceptibility to SARS-CoV-2 infection. Given the pressing need for clarity on which viral targets may lead to promising therapeutics, we present these findings to allow more informed decisions about the translational relevance of this putative mechanism in the race to understand and treat COVID-19.


Subject(s)
Basigin/metabolism , COVID-19/metabolism , Receptors, Virus/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , COVID-19/virology , Cell Line , HEK293 Cells , Host-Pathogen Interactions , Humans , Protein Binding , Virus Internalization
13.
mBio ; 11(6)2020 12 11.
Article in English | MEDLINE | ID: covidwho-975645

ABSTRACT

SARS-CoV-2 causes COVID-19, an acute respiratory distress syndrome (ARDS) characterized by pulmonary edema, viral pneumonia, multiorgan dysfunction, coagulopathy, and inflammation. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) receptors to infect and damage ciliated epithelial cells in the upper respiratory tract. In alveoli, gas exchange occurs across an epithelial-endothelial barrier that ties respiration to endothelial cell (EC) regulation of edema, coagulation, and inflammation. How SARS-CoV-2 dysregulates vascular functions to cause ARDS in COVID-19 patients remains an enigma focused on dysregulated EC responses. Whether SARS-CoV-2 directly or indirectly affects functions of the endothelium remains to be resolved and is critical to understanding SARS-CoV-2 pathogenesis and therapeutic targets. We demonstrate that primary human ECs lack ACE2 receptors at protein and RNA levels and that SARS-CoV-2 is incapable of directly infecting ECs derived from pulmonary, cardiac, brain, umbilical vein, or kidney tissues. In contrast, pulmonary ECs transduced with recombinant ACE2 receptors are infected by SARS-CoV-2 and result in high viral titers (∼1 × 107/ml), multinucleate syncytia, and EC lysis. SARS-CoV-2 infection of ACE2-expressing ECs elicits procoagulative and inflammatory responses observed in COVID-19 patients. The inability of SARS-CoV-2 to directly infect and lyse ECs without ACE2 expression explains the lack of vascular hemorrhage in COVID-19 patients and indicates that the endothelium is not a primary target of SARS-CoV-2 infection. These findings are consistent with SARS-CoV-2 indirectly activating EC programs that regulate thrombosis and endotheliitis in COVID-19 patients and focus strategies on therapeutically targeting epithelial and inflammatory responses that activate the endothelium or initiate limited ACE2-independent EC infection.IMPORTANCE SARS-CoV-2 infects pulmonary epithelial cells through ACE2 receptors and causes ARDS. COVID-19 causes progressive respiratory failure resulting from diffuse alveolar damage and systemic coagulopathy, thrombosis, and capillary inflammation that tie alveolar responses to EC dysfunction. This has prompted theories that SARS-CoV-2 directly infects ECs through ACE2 receptors, yet SARS-CoV-2 antigen has not been colocalized with ECs and prior studies indicate that ACE2 colocalizes with alveolar epithelial cells and vascular smooth muscle cells, not ECs. Here, we demonstrate that primary human ECs derived from lung, kidney, heart, brain, and umbilical veins require expression of recombinant ACE2 receptors in order to be infected by SARS-CoV-2. However, SARS-CoV-2 lytically infects ACE2-ECs and elicits procoagulative and inflammatory responses observed in COVID-19 patients. These findings suggest a novel mechanism of COVID-19 pathogenesis resulting from indirect EC activation, or infection of a small subset of ECs by an ACE2-independent mechanism, that transforms rationales and targets for therapeutic intervention.


Subject(s)
Blood Coagulation Factors , Endothelial Cells/virology , Inflammation , Peptidyl-Dipeptidase A/genetics , SARS-CoV-2/pathogenicity , Animals , Cells, Cultured , Chlorocebus aethiops , Endothelial Cells/immunology , Endothelial Cells/pathology , Humans , Recombinant Proteins , Vero Cells
14.
Ann Thorac Surg ; 111(4): e241-e243, 2021 04.
Article in English | MEDLINE | ID: covidwho-956092

ABSTRACT

We report a case of necrotizing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia complicated by a bronchopleural fistula and treated by decortication and salvage lobectomy. Owing to the unknown characteristics of the underlying SARS-CoV-2 infection, treatment of the abscess and bronchopleural fistula was delayed. This may have resulted in further deterioration of the patient, with ensuing multiple organ dysfunction. Complications of SARS-CoV-2 pneumonia, such as a bacterial abscess and a bronchopleural fistula, should be treated as if the patient were not infected with SARS-CoV-2.


Subject(s)
Bronchial Fistula/surgery , COVID-19/complications , Lung/diagnostic imaging , Pleural Diseases/surgery , Pneumonectomy/methods , Pneumonia, Viral/complications , Adult , Bronchial Fistula/diagnosis , Bronchial Fistula/etiology , COVID-19/diagnosis , COVID-19/epidemiology , Female , Humans , Lung/surgery , Pleural Diseases/diagnosis , Pleural Diseases/etiology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/surgery , Tomography, X-Ray Computed
15.
Stem Cells Transl Med ; 10(4): 636-642, 2021 04.
Article in English | MEDLINE | ID: covidwho-921740

ABSTRACT

Anti-inflammatory and immune-modulatory therapies have been proposed for the treatment of COVID-19 and its most serious complications. Among others, the use of mesenchymal stromal cells (MSCs) is under investigation given their well-documented anti-inflammatory and immunomodulatory properties. However, some critical issues regarding the possibility that MSCs could be infected by the virus have been raised. Angiotensin-converting enzyme 2 (ACE2) and type II transmembrane serine protease (TMPRSS2) are the main host cell factors for the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), entry, but so far it is unclear if human MSCs do or do not express these two proteins. To elucidate these important aspects, we evaluated if human MSCs from both fetal and adult tissues constitutively express ACE2 and TMPRSS2 and, most importantly, if they can be infected by SARS-CoV-2. We evaluated human MSCs derived from amnios, cord blood, cord tissue, adipose tissue, and bone marrow. ACE2 and TMPRSS2 were expressed by the SARS-CoV-2-permissive human pulmonary Calu-3 cell line but not by all the MSCs tested. MSCs were then exposed to SARS-CoV-2 wild strain without evidence of cytopathic effect. Moreover, we also excluded that the MSCs could be infected without showing lytic effects since their conditioned medium after SARS-CoV-2 exposure did not contain viral particles. Our data, demonstrating that MSCs derived from different human tissues are not permissive to SARS-CoV-2 infection, support the safety of MSCs as potential therapy for COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , COVID-19/immunology , Gene Expression Regulation/immunology , Mesenchymal Stem Cells/immunology , SARS-CoV-2/immunology , Serine Endopeptidases/immunology , Cells, Cultured , Humans
16.
Sci Rep ; 10(1): 18995, 2020 11 04.
Article in English | MEDLINE | ID: covidwho-910353

ABSTRACT

The current pandemic is caused by the SARS-CoV-2 virus and large progress in understanding the pathology of the virus has been made since its emergence in late 2019. Several reports indicate short lasting immunity against endemic coronaviruses, which contrasts studies showing that biobanked venous blood contains T cells reactive to SARS-CoV-2 S-protein even before the outbreak in Wuhan. This suggests a preformed T cell memory towards structural proteins in individuals not exposed to SARS-CoV-2. Given the similarity of SARS-CoV-2 to other members of the Coronaviridae family, the endemic coronaviruses appear likely candidates to generate this T cell memory. However, given the apparent poor immunological memory created by the endemic coronaviruses, immunity against other common pathogens might offer an alternative explanation. Here, we utilize a combination of epitope prediction and similarity to common human pathogens to identify potential sources of the SARS-CoV-2 T cell memory. Although beta-coronaviruses are the most likely candidates to explain the pre-existing SARS-CoV-2 reactive T cells in uninfected individuals, the SARS-CoV-2 epitopes with the highest similarity to those from beta-coronaviruses are confined to replication associated proteins-not the host interacting S-protein. Thus, our study suggests that the observed SARS-CoV-2 pre-formed immunity to structural proteins is not driven by near-identical epitopes.


Subject(s)
Coronavirus Infections/immunology , Epitopes/immunology , Immunologic Memory , Pneumonia, Viral/immunology , T-Lymphocytes/immunology , Viral Structural Proteins/immunology , Antigens, Viral/chemistry , Antigens, Viral/immunology , Betacoronavirus/immunology , COVID-19 , Epitopes/chemistry , Humans , Pandemics , SARS-CoV-2 , Viral Structural Proteins/chemistry
17.
Tidsskr Nor Laegeforen ; 140(14)2020 10 13.
Article in English, Norwegian | MEDLINE | ID: covidwho-883917

ABSTRACT

BACKGROUND: The course of COVID-19 may be particularly long-lasting in elderly patients. Caring for patients with dementia suffering from COVID-19 is challenging due to unclear symptom presentation, delirium, and maintaining isolation procedures. CASE PRESENTATION: A man in his sixties with dementia, hospitalised in a psychogeriatric ward, presented with mild upper respiratory tract symptoms and recovered within 24 hours. Ten days later he developed more severe symptoms. PCR test for SARS-CoV-2 was positive. Over the following two months his clinical state fluctuated, from almost symptom-free days to being bedridden and assessed as potentially terminal. After the initial positive test, he had three consecutive negative tests, before he again tested positive for SARS-CoV-2. Uncertainty as to whether the patient remained contagious resulted in isolation of the patient for over two months. INTERPRETATION: PCR testing of SARS-CoV-2 does not differentiate between intact virus and remnants thereof, and patients may test positive for a long time. This along with a fluctuating clinical course makes it difficult for clinicians to decide when to end isolation of COVID-19 patients.


Subject(s)
Coronavirus Infections , Dementia , Pandemics , Pneumonia, Viral , Severe Acute Respiratory Syndrome , Aged , Betacoronavirus , COVID-19 , Coronavirus Infections/complications , Dementia/complications , Humans , Male , Pneumonia, Viral/complications , SARS-CoV-2 , Severe Acute Respiratory Syndrome/epidemiology , Time Factors
18.
Microb Risk Anal ; 16: 100140, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-779468

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Middle East respiratory syndrome coronavirus (MERS-CoV) infect the human respiratory tract. A prototype thermodynamic equilibrium model is presented here for the probability of the virions getting through the mucus barrier and infecting epithelial cells based on the binding affinity (Kmucin) of the virions to mucin molecules in the mucus and parameters for binding and infection of the epithelial cell. Both MERS-CoV and SARS-CoV-2 bind strongly to their cellular receptors, DDP4 and ACE2, respectively, and infect very efficiently both bronchus and lung ex vivo cell cultures which are not protected by a mucus barrier. According to the model, mucin binding could reduce the infectivity for MERS-CoV compared to SARS-CoV-2 by at least 100-fold depending on the magnitude of Kmucin. Specifically Kmucin values up to 106 M-1 have little protective effect and thus the mucus barrier would not remove SARS-CoV-2 which does not bind to sialic acids (SA) and hence would have a very low Kmucin. Depending on the viability of individual virions, the ID50 for SARS-CoV-2 is estimated to be ~500 virions (viral RNA genomic copies) representing 1 to 2 pfu. In contrast MERS-CoV binds both SA and human mucin and a Kmucin of 5 × 109 M-1 as reported for lectins would mop up 99.83% of the virus according to the model with the ID50 for MERS-CoV estimated to be ~295,000 virions (viral RNA genomic copies) representing 819 pfu. This could in part explain why MERS-CoV is poorly transmitted from human to human compared to SARS-CoV-2. Some coronaviruses use an esterase to escape the mucin, although MERS-CoV does not. Instead, it is shown here that "clustering" of virions into single aerosol particles as recently reported for rotavirus in extracellular vesicles could provide a co-operative mechanism whereby MERS-CoV could theoretically overcome the mucin barrier locally and a small proportion of 10 µm diameter aerosol particles could contain ~70 virions based on reported maximum levels in saliva. Although recent evidence suggests SARS-CoV-2 initiates infection in the nasal epithelium, the thermodynamic equilibrium models presented here could complement published approaches for modelling the physical entry of pathogens to the lung based on the fate and transport of the pathogen particles (as for anthrax spores) to develop a dose-response model for aerosol exposure to respiratory viruses. This would enable the infectivity through aerosols to be defined based on molecular parameters as well as physical parameters. The role of the spike proteins of MERS-CoV and SARS-CoV-2 binding to SA and heparan sulphate, respectively, may be to aid non-specific attachment to the host cell. It is proposed that a high Kmucin is the cost for subsequent binding of MERS-CoV to SAs on the cell surface to partially overcome the unfavourable entropy of immobilisation as the virus adopts the correct orientation for spike protein interactions with its protein cellular receptor DPP4.

19.
J Gastroenterol Hepatol ; 36(3): 646-656, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-780938

ABSTRACT

Exclusion of nausea (N) and vomiting (V) from detailed consideration as symptoms of COVID-19 is surprising as N can be an early presenting symptom. We examined the incidence of NV during infection before defining potential mechanisms. We estimate that the overall incidence of nausea (median 10.5%), although variable, is comparable with diarrhea. Poor definition of N, confusion with appetite loss, and reporting of N and/or V as a single entity may contribute to reporting variability and likely underestimation. We propose that emetic mechanisms are activated by mediators released from the intestinal epithelium by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) modulate vagal afferents projecting to the brainstem and after entry into the blood, activate the area postrema (AP) also implicated in anorexia. The receptor for spike protein of SARS-CoV-2, angiotensin 2 converting enzyme (ACE2), and transmembrane protease serine (for viral entry) is expressed in upper gastrointestinal (GI) enterocytes, ACE2 is expressed on enteroendocrine cells (EECs), and SARS-CoV-2 infects enterocytes but not EECs (studies needed with native EECs). The resultant virus-induced release of epithelial mediators due to exocytosis, inflammation, and apoptosis provides the peripheral and central emetic drives. Additionally, data from SARS-CoV-2 show an increase in plasma angiotensin II (consequent on SARS-CoV-2/ACE2 interaction), a centrally (AP) acting emetic, providing a further potential mechanism in COVID-19. Viral invasion of the dorsal brainstem is also a possibility but more likely in delayed onset symptoms. Overall, greater attention must be given to nausea as an early symptom of COVID-19 and for the insights provided into the GI effects of SARS-CoV-2.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Nausea/virology , Vomiting/virology , COVID-19/complications , COVID-19/physiopathology , COVID-19/virology , Humans , Incidence , Nausea/epidemiology , Vomiting/epidemiology
20.
Transfusion ; 60(12): 2938-2951, 2020 12.
Article in English | MEDLINE | ID: covidwho-767657

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) collection began in two Brazilian hospitals for treatment of severe/critical patients. METHODS AND MATERIALS: Mild/moderate COVID-19 convalescents were selected as CCP donors after reverse transcription polymerase chain reaction (RT-PCR) confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and absence of symptoms for ≥14 days plus (a) age (18-60 years), body weight greater than 55 kg; (b) immunohematological studies; (c) no infectious markers of hepatitis B virus, hepatitis C virus, human immunodeficiency virus, human T-lymphotropic virus-1/2, Chagas and syphilis infection; (d) no HLA antibodies (multiparous); (e) second RT-PCR (nasopharyngeal swab and/or blood) negativity; (f) virus neutralization test (cytopathic effect-based virus neutralization test neutralizing antibody) and anti-nucleocapsid protein SARS-CoV-2 IgM, IgG, and IgA enzyme-linked immunosorbent assays. RESULTS: Among 271 donors (41 females, 230 males), 250 presented with neutralizing antibodies. Final RT-PCR was negative on swab (77.0%) or blood (88.4%; P = .46). Final definition of RT-PCR was only defined at more than 28 days after full recovery in 59 of 174 (33.9%) RT-PCR -ve, and 25/69 RT-PCR +ve (36.2%; 13 between 35 and 48 days). Neutralizing antibody titers of 160 or greater were found in 63.6%. Correlation between IgG signal/cutoff of 5.0 or greater and neutralizing antibody of 160 or greater was 82.4%. Combination of final RT-PCR -ve with neutralizing antibody ≥160 was 41.3% (112/271). Serial plasma collection showed decline in neutralizing antibody titers and IgA levels (P < .05), probably denoting a "golden period" for CCP collection (≤28 days after joining the program); IgA might have an important role as neutralizing antibody. Donor's weight, days between disease onset and serial plasma collection, and IgG and IgM levels are important predictors for neutralizing antibody titer. CONCLUSIONS: RT-PCR +ve cases are still detected in 36.2% within 28 to 48 days after recovery. High anti-nucleocapsid protein IgG levels may be used as a surrogate marker to neutralizing antibody.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/blood , COVID-19/therapy , Convalescence , Donor Selection/statistics & numerical data , SARS-CoV-2/immunology , Adult , Blood Donors , Brazil/epidemiology , COVID-19/immunology , COVID-19 Nucleic Acid Testing , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunization, Passive , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Time Factors , Young Adult
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