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1.
Science ; 375(6579): 449-454, 2022 Jan 28.
Article in English | MEDLINE | ID: covidwho-1723472

ABSTRACT

Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures against SARS-CoV-2 variants and future zoonotic sarbecoviruses. We describe the isolation and characterization of a human monoclonal antibody, designated S2K146, that broadly neutralizes viruses belonging to SARS-CoV- and SARS-CoV-2-related sarbecovirus clades which use ACE2 as an entry receptor. Structural and functional studies show that most of the virus residues that directly bind S2K146 are also involved in binding to ACE2. This allows the antibody to potently inhibit receptor attachment. S2K146 protects against SARS-CoV-2 Beta challenge in hamsters and viral passaging experiments reveal a high barrier for emergence of escape mutants, making it a good candidate for clinical development. The conserved ACE2-binding residues present a site of vulnerability that might be leveraged for developing vaccines eliciting broad sarbecovirus immunity.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/immunology , Betacoronavirus/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/therapy , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/metabolism , Antibodies, Monoclonal/therapeutic use , Antibodies, Viral/chemistry , Antibodies, Viral/metabolism , Antibody Affinity , Broadly Neutralizing Antibodies/chemistry , Broadly Neutralizing Antibodies/metabolism , Broadly Neutralizing Antibodies/therapeutic use , COVID-19/immunology , Cross Reactions , Cryoelectron Microscopy , Epitopes , Humans , Immune Evasion , Mesocricetus , Models, Molecular , Molecular Mimicry , Mutation , Protein Conformation , Protein Domains , Receptors, Coronavirus/chemistry , Receptors, Coronavirus/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
2.
PLoS Med ; 19(3): e1003922, 2022 03.
Article in English | MEDLINE | ID: covidwho-1714706

ABSTRACT

BACKGROUND: The risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission through corneal graft is an ongoing debate and leads to strict restrictions in corneas procurement, leading to a major decrease in eye banking activity. The aims of this study are to specifically assess the capacity of human cornea to be infected by SARS-CoV-2 and promote its replication ex vivo, and to evaluate the real-life risk of corneal contamination by detecting SARS-CoV-2 RNA in corneas retrieved in donors diagnosed with Coronavirus Disease 2019 (COVID-19) and nonaffected donors. METHODS AND FINDINGS: To assess the capacity of human cornea to be infected by SARS-CoV-2, the expression pattern of SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE-2) and activators TMPRSS2 and Cathepsins B and L in ocular surface tissues from nonaffected donors was explored by immunohistochemistry (n = 10 corneas, 78 ± 11 years, 40% female) and qPCR (n = 5 corneas, 80 ± 12 years, 40% female). Additionally, 5 freshly excised corneas (80 ± 12 years, 40% female) were infected ex vivo with highly concentrated SARS-CoV-2 solution (106 median tissue culture infectious dose (TCID50)/mL). Viral RNA was extracted from tissues and culture media and quantified by reverse transcription quantitative PCR (RT-qPCR) (viral RNA copies) 30 minutes (H0) and 24 hours (H24) after infection. To assess the risk of corneal contamination by SARS-CoV-2, viral RNA was tested by RT-qPCR (Ct value) in both corneas and organ culture media from 14 donors diagnosed with COVID-19 (74 ± 10 years, 29% female) and 26 healthy donors (79 ± 13 years, 57% female), and in organ culture media only from 133 consecutive nonaffected donors from 2 eye banks (73 ± 13 years, 29% female). The expression of receptor and activators was variable among samples at both protein and mRNA level. Based on immunohistochemistry findings, ACE-2 was localized mainly in the most superficial epithelial cells of peripheral cornea, limbus, and conjunctiva, whereas TMPRSS2 was mostly expressed in all layers of bulbar conjunctiva. A significant increase in total and positive strands of IP4 RNA sequence (RdRp viral gene) was observed from 30 minutes to 24 hours postinfection in central cornea (1.1 × 108 [95% CI: 6.4 × 107 to 2.4 × 108] to 3.0 × 109 [1.4 × 109 to 5.3 × 109], p = 0.0039 and 2.2 × 107 [1.4 × 107 to 3.6 × 107] to 5.1 × 107 [2.9 × 107 to 7.5 × 107], p = 0.0117, respectively) and in corneoscleral rim (4.5 × 109 [2.7 × 109 to 9.6 × 109] to 3.9 × 1010 [2.6 × 1010 to 4.4 × 1010], p = 0.0039 and 3.1 × 108 [1.2 × 108 to 5.3 × 108] to 7.8 × 108 [3.9 × 108 to 9.9 × 108], p = 0.0391, respectively). Viral RNA copies in ex vivo corneas were highly variable from one donor to another. Finally, viral RNA was detected in 3 out of 28 corneas (11%) from donors diagnosed with COVID-19. All samples from the 159 nonaffected donors were negative for SARS-CoV-2 RNA. The main limitation of this study relates to the limited sample size, due to limited access to donors diagnosed with COVID-19 and concomitant decrease in the procurement corneas from nonaffected donors. CONCLUSIONS: In this study, we observed the expression of SARS-CoV-2 receptors and activators at the human ocular surface and a variable increase in viral RNA copies 24 hours after experimental infection of freshly excised human corneas. We also found viral RNA only in a very limited percentage of donors with positive nasopharyngeal PCR. The low rate of positivity in donors diagnosed with COVID-19 calls into question the utility of donor selection algorithms. TRIAL REGISTRATION: Agence de la Biomédecine, PFS-20-011 https://www.agence-biomedecine.fr/.


Subject(s)
COVID-19/complications , Cornea/virology , Corneal Diseases/virology , Eye Infections, Viral/virology , SARS-CoV-2/physiology , Adult , Aged , Angiotensin-Converting Enzyme 2/metabolism , Animals , Cathepsins/metabolism , Chlorocebus aethiops , Cornea/metabolism , Culture Media , Female , Humans , Male , Middle Aged , Organ Culture Techniques , RNA, Viral/metabolism , Receptors, Coronavirus/metabolism , Serine Endopeptidases/metabolism , Vero Cells , Virus Replication
3.
Science ; 375(6583): 864-868, 2022 02 25.
Article in English | MEDLINE | ID: covidwho-1650843

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant of concern evades antibody-mediated immunity that comes from vaccination or infection with earlier variants due to accumulation of numerous spike mutations. To understand the Omicron antigenic shift, we determined cryo-electron microscopy and x-ray crystal structures of the spike protein and the receptor-binding domain bound to the broadly neutralizing sarbecovirus monoclonal antibody (mAb) S309 (the parent mAb of sotrovimab) and to the human ACE2 receptor. We provide a blueprint for understanding the marked reduction of binding of other therapeutic mAbs that leads to dampened neutralizing activity. Remodeling of interactions between the Omicron receptor-binding domain and human ACE2 likely explains the enhanced affinity for the host receptor relative to the ancestral virus.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Viral/chemistry , Immune Evasion , Receptors, Coronavirus/chemistry , SARS-CoV-2/chemistry , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Amino Acid Substitution , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/metabolism , Antibodies, Viral/immunology , Antibodies, Viral/metabolism , Broadly Neutralizing Antibodies/chemistry , Broadly Neutralizing Antibodies/immunology , Broadly Neutralizing Antibodies/metabolism , Cryoelectron Microscopy , Crystallography, X-Ray , Humans , Models, Molecular , Mutation , Protein Binding , Protein Conformation , Protein Domains/genetics , Protein Interaction Domains and Motifs/genetics , Receptors, Coronavirus/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
4.
Science ; 375(6578): eabl6251, 2022 01 21.
Article in English | MEDLINE | ID: covidwho-1650842

ABSTRACT

Many studies have examined the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants on neutralizing antibody activity after they have become dominant strains. Here, we evaluate the consequences of further viral evolution. We demonstrate mechanisms through which the SARS-CoV-2 receptor binding domain (RBD) can tolerate large numbers of simultaneous antibody escape mutations and show that pseudotypes containing up to seven mutations, as opposed to the one to three found in previously studied variants of concern, are more resistant to neutralization by therapeutic antibodies and serum from vaccine recipients. We identify an antibody that binds the RBD core to neutralize pseudotypes for all tested variants but show that the RBD can acquire an N-linked glycan to escape neutralization. Our findings portend continued emergence of escape variants as SARS-CoV-2 adapts to humans.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Immune Evasion , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Betacoronavirus/immunology , COVID-19/immunology , COVID-19/virology , Cross Reactions , Cryoelectron Microscopy , Crystallography, X-Ray , Epitopes , Evolution, Molecular , Humans , Models, Molecular , Mutation , Polysaccharides/analysis , Protein Binding , Protein Domains , Receptors, Coronavirus/chemistry , Receptors, Coronavirus/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
5.
Science ; 375(6582): 760-764, 2022 Feb 18.
Article in English | MEDLINE | ID: covidwho-1635132

ABSTRACT

The newly reported Omicron variant is poised to replace Delta as the most prevalent SARS-CoV-2 variant across the world. Cryo-EM structural analysis of the Omicron variant spike protein in complex with human ACE2 reveals new salt bridges and hydrogen bonds formed by mutated residues R493, S496 and R498 in the RBD with ACE2. These interactions appear to compensate for other Omicron mutations such as K417N known to reduce ACE2 binding affinity, resulting in similar biochemical ACE2 binding affinities for Delta and Omicron variants. Neutralization assays show that pseudoviruses displaying the Omicron spike protein exhibit increased antibody evasion. The increase in antibody evasion, together with retention of strong interactions at the ACE2 interface, thus represent important molecular features that likely contribute to the rapid spread of the Omicron variant.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Viral/immunology , Immune Evasion , Receptors, Coronavirus/chemistry , SARS-CoV-2/chemistry , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19 Vaccines/immunology , Cryoelectron Microscopy , Humans , Hydrogen Bonding , Models, Molecular , Mutation , Neutralization Tests , Protein Binding , Protein Domains , Protein Interaction Domains and Motifs , Receptors, Coronavirus/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
6.
Science ; 373(6556)2021 Aug 13.
Article in English | MEDLINE | ID: covidwho-1559379

ABSTRACT

The emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) that are resistant to therapeutic antibodies highlights the need for continuing discovery of broadly reactive antibodies. We identified four receptor binding domain-targeting antibodies from three early-outbreak convalescent donors with potent neutralizing activity against 23 variants, including the B.1.1.7, B.1.351, P.1, B.1.429, B.1.526, and B.1.617 VOCs. Two antibodies are ultrapotent, with subnanomolar neutralization titers [half-maximal inhibitory concentration (IC50) 0.3 to 11.1 nanograms per milliliter; IC80 1.5 to 34.5 nanograms per milliliter). We define the structural and functional determinants of binding for all four VOC-targeting antibodies and show that combinations of two antibodies decrease the in vitro generation of escape mutants, suggesting their potential in mitigating resistance development.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/metabolism , Antibodies, Viral/chemistry , Antibodies, Viral/metabolism , Antibody Affinity , Antigen-Antibody Reactions , COVID-19/virology , Humans , Immune Evasion , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fab Fragments/metabolism , Mutation , Neutralization Tests , Protein Domains , Receptors, Coronavirus/antagonists & inhibitors , Receptors, Coronavirus/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
7.
Viruses ; 13(11)2021 11 15.
Article in English | MEDLINE | ID: covidwho-1524171

ABSTRACT

Angiotensin-converting enzyme 2 (ACE2) is a main receptor for SARS-CoV-2 entry to the host cell. Indeed, the first step in viral entry is the binding of the viral trimeric spike (S) protein to ACE2. Abundantly present in human epithelial cells of many organs, ACE2 is also expressed in the human brain. ACE2 is a type I membrane protein with an extracellular N-terminal peptidase domain and a C-terminal collectrin-like domain that ends with a single transmembrane helix and an intracellular 44-residue segment. This C-terminal segment contains a PDZ-binding motif (PBM) targeting protein-interacting domains called PSD-95/Dlg/ZO-1 (PDZ). Here, we identified the human PDZ specificity profile of the ACE2 PBM using the high-throughput holdup assay and measuring the binding intensities of the PBM of ACE2 against the full human PDZome. We discovered 14 human PDZ binders of ACE2 showing significant binding with dissociation constants' values ranging from 3 to 81 µM. NHERF, SHANK, and SNX27 proteins found in this study are involved in protein trafficking. The PDZ/PBM interactions with ACE2 could play a role in ACE2 internalization and recycling that could be of benefit for the virus entry. Interestingly, most of the ACE2 partners we identified are expressed in neuronal cells, such as SHANK and MAST families, and modifications of the interactions between ACE2 and these neuronal proteins may be involved in the neurological symptoms of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , PDZ Domains , Proteins/chemistry , Proteins/metabolism , Receptors, Coronavirus/metabolism , Humans , Microtubule-Associated Proteins/chemistry , Microtubule-Associated Proteins/metabolism , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/metabolism , Neurons/metabolism , Phosphoproteins/chemistry , Phosphoproteins/metabolism , /metabolism , Protein Transport , Sodium-Hydrogen Exchangers/chemistry , Sodium-Hydrogen Exchangers/metabolism , Sorting Nexins/chemistry , Sorting Nexins/metabolism
9.
Neurobiol Dis ; 161: 105561, 2021 12.
Article in English | MEDLINE | ID: covidwho-1510138

ABSTRACT

Coronavirus disease 19 (COVID-19) is a respiratory illness caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). COVID-19 pathogenesis causes vascular-mediated neurological disorders via elusive mechanisms. SARS-CoV-2 infects host cells via the binding of viral Spike (S) protein to transmembrane receptor, angiotensin-converting enzyme 2 (ACE2). Although brain pericytes were recently shown to abundantly express ACE2 at the neurovascular interface, their response to SARS-CoV-2 S protein is still to be elucidated. Using cell-based assays, we found that ACE2 expression in human brain vascular pericytes was increased upon S protein exposure. Pericytes exposed to S protein underwent profound phenotypic changes associated with an elongated and contracted morphology accompanied with an enhanced expression of contractile and myofibrogenic proteins, such as α-smooth muscle actin (α-SMA), fibronectin, collagen I, and neurogenic locus notch homolog protein-3 (NOTCH3). On the functional level, S protein exposure promoted the acquisition of calcium (Ca2+) signature of contractile ensheathing pericytes characterized by highly regular oscillatory Ca2+ fluctuations. Furthermore, S protein induced lipid peroxidation, oxidative and nitrosative stress in pericytes as well as triggered an immune reaction translated by activation of nuclear factor-kappa-B (NF-κB) signaling pathway, which was potentiated by hypoxia, a condition associated with vascular comorbidities that exacerbate COVID-19 pathogenesis. S protein exposure combined to hypoxia enhanced the production of pro-inflammatory cytokines involved in immune cell activation and trafficking, namely macrophage migration inhibitory factor (MIF). Using transgenic mice expressing the human ACE2 that recognizes S protein, we observed that the intranasal infection with SARS-CoV-2 rapidly induced hypoxic/ischemic-like pericyte reactivity in the brain of transgenic mice, accompanied with an increased vascular expression of ACE2. Moreover, we found that SARS-CoV-2 S protein accumulated in the intranasal cavity reached the brain of mice in which the nasal mucosa is deregulated. Collectively, these findings suggest that SARS-CoV-2 S protein impairs the vascular and immune regulatory functions of brain pericytes, which may account for vascular-mediated brain damage. Our study provides a better understanding for the mechanisms underlying cerebrovascular disorders in COVID-19, paving the way to develop new therapeutic interventions.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Brain/metabolism , COVID-19/metabolism , Hypoxia-Ischemia, Brain/metabolism , Hypoxia/metabolism , Inflammation/metabolism , Pericytes/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Actins/metabolism , Angiotensin-Converting Enzyme 2/drug effects , Angiotensin-Converting Enzyme 2/genetics , Animals , Brain/blood supply , COVID-19/physiopathology , Calcium Signaling , Collagen Type I/metabolism , Fibronectins/metabolism , Humans , Hypoxia-Ischemia, Brain/physiopathology , Lipid Peroxidation/drug effects , Lipid Peroxidation/genetics , Macrophage Migration-Inhibitory Factors/drug effects , Macrophage Migration-Inhibitory Factors/metabolism , Mice , Mice, Transgenic , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/cytology , Myocytes, Smooth Muscle/metabolism , Myofibroblasts , NF-kappa B/drug effects , NF-kappa B/metabolism , Nasal Mucosa , Nitrosative Stress , Oxidative Stress , Pericytes/cytology , Pericytes/drug effects , Phenotype , Receptor, Notch3/metabolism , Receptors, Coronavirus/drug effects , Receptors, Coronavirus/genetics , Receptors, Coronavirus/metabolism , Spike Glycoprotein, Coronavirus/pharmacology
10.
Science ; 374(6575): 1621-1626, 2021 Dec 24.
Article in English | MEDLINE | ID: covidwho-1506414

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission leads to the emergence of variants, including the B.1.617.2 (Delta) variant of concern that is causing a new wave of infections and has become globally dominant. We show that these variants dampen the in vitro potency of vaccine-elicited serum neutralizing antibodies and provide a structural framework for describing their immune evasion. Mutations in the B.1.617.1 (Kappa) and Delta spike glycoproteins abrogate recognition by several monoclonal antibodies via alteration of key antigenic sites, including remodeling of the Delta amino-terminal domain. The angiotensin-converting enzyme 2 binding affinities of the Kappa and Delta receptor binding domains are comparable to the Wuhan-Hu-1 isolate, whereas B.1.617.2+ (Delta+) exhibits markedly reduced affinity.


Subject(s)
COVID-19 Vaccines/immunology , Immune Evasion , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , /immunology , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/metabolism , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antibodies, Viral/metabolism , Antigens, Viral/chemistry , Antigens, Viral/immunology , Cryoelectron Microscopy , Humans , Models, Molecular , Mutation , Protein Binding , Protein Conformation , Protein Domains , Protein Folding , Receptors, Coronavirus/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
11.
Chem Biol Interact ; 351: 109738, 2022 Jan 05.
Article in English | MEDLINE | ID: covidwho-1503574

ABSTRACT

The rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19), has had a dramatic negative impact on public health and economies worldwide. Recent studies on COVID-19 complications and mortality rates suggest that there is a higher prevalence in cardiovascular diseases (CVD) patients. Past investigations on the associations between pre-existing CVDs and susceptibility to coronavirus infections including SARS-CoV and the Middle East Respiratory Syndrome coronavirus (MERS-CoV), have demonstrated similar results. However, the underlying mechanisms are poorly understood. This has impeded adequate risk stratification and treatment strategies for CVD patients with SARS-CoV-2 infections. Generally, dysregulation of the expression of angiotensin-converting enzyme (ACE) and the counter regulator, angiotensin-converting enzyme 2 (ACE2) is a hallmark of cardiovascular risk and CVD. ACE2 is the main host receptor for SARS-CoV-2. Although further studies are required, dysfunction of ACE2 after virus binding and dysregulation of the renin-angiotensin-aldosterone system (RAAS) signaling may worsen the outcomes of people affected by COVID-19 and with preexisting CVD. Here, we review the current knowledge and outline the gaps related to the relationship between CVD and COVID-19 with a focus on the RAAS. Improved understanding of the mechanisms regulating viral entry and the role of RAAS may direct future research with the potential to improve the prevention and management of COVID-19.


Subject(s)
COVID-19/physiopathology , Cardiovascular Diseases/physiopathology , Renin-Angiotensin System/physiology , Angiotensin Receptor Antagonists/therapeutic use , Angiotensin-Converting Enzyme 2/metabolism , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , COVID-19/complications , COVID-19/drug therapy , Cardiovascular Diseases/complications , Humans , Receptors, Coronavirus/metabolism , Risk Factors , SARS-CoV-2/drug effects
12.
Viruses ; 13(11)2021 11 04.
Article in English | MEDLINE | ID: covidwho-1502532

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative pathogen of coronavirus disease 2019 (COVID-19). It is known as a respiratory virus, but SARS-CoV-2 appears equally, or even more, infectious for the olfactory epithelium (OE) than for the respiratory epithelium in the nasal cavity. In light of the small area of the OE relative to the respiratory epithelium, the high prevalence of olfactory dysfunctions (ODs) in COVID-19 has been bewildering and has attracted much attention. This review aims to first examine the cytological and molecular biological characteristics of the OE, especially the microvillous apical surfaces of sustentacular cells and the abundant SARS-CoV-2 receptor molecules thereof, that may underlie the high susceptibility of this neuroepithelium to SARS-CoV-2 infection and damages. The possibility of SARS-CoV-2 neurotropism, or the lack of it, is then analyzed with regard to the expression of the receptor (angiotensin-converting enzyme 2) or priming protease (transmembrane serine protease 2), and cellular targets of infection. Neuropathology of COVID-19 in the OE, olfactory bulb, and other related neural structures are also reviewed. Toward the end, we present our perspectives regarding possible mechanisms of SARS-CoV-2 neuropathogenesis and ODs, in the absence of substantial viral infection of neurons. Plausible causes for persistent ODs in some COVID-19 convalescents are also examined.


Subject(s)
Anosmia/epidemiology , Anosmia/etiology , COVID-19/complications , Olfactory Mucosa/virology , SARS-CoV-2/physiology , Viral Tropism , Angiotensin-Converting Enzyme 2/metabolism , Anosmia/physiopathology , COVID-19/pathology , COVID-19/virology , Humans , Olfactory Bulb/pathology , Olfactory Bulb/virology , Olfactory Mucosa/metabolism , Olfactory Mucosa/ultrastructure , Prevalence , Receptors, Coronavirus/metabolism
13.
J Infect Dis ; 224(8): 1357-1361, 2021 10 28.
Article in English | MEDLINE | ID: covidwho-1493824

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 ) initiates entry into airway epithelia by binding its receptor, angiotensin-converting enzyme 2 (ACE2). METHODS: To explore whether interindividual variation in ACE2 abundance contributes to variability in coronavirus disease 2019 (COVID-19) outcomes, we measured ACE2 protein abundance in primary airway epithelial cultures derived from 58 human donor lungs. RESULTS: We found no evidence for sex- or age-dependent differences in ACE2 protein expression. Furthermore, we found that variations in ACE2 abundance had minimal effects on viral replication and induction of the interferon response in airway epithelia infected with SARS-CoV-2. CONCLUSIONS: Our results highlight the relative importance of additional host factors, beyond viral receptor expression, in determining COVID-19 lung disease outcomes.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/pathology , Receptors, Coronavirus/metabolism , SARS-CoV-2/metabolism , Angiotensin-Converting Enzyme 2/analysis , Biological Variation, Population , Bronchi/cytology , Bronchi/pathology , Bronchi/virology , COVID-19/virology , Epithelial Cells , Female , Humans , Male , Primary Cell Culture , Receptors, Coronavirus/analysis , Respiratory Mucosa/cytology , Respiratory Mucosa/metabolism , Respiratory Mucosa/pathology , Respiratory Mucosa/virology , Sex Factors , Virus Internalization
14.
Molecules ; 26(21)2021 Oct 26.
Article in English | MEDLINE | ID: covidwho-1488676

ABSTRACT

A novel human coronavirus prompted considerable worry at the end of the year 2019. Now, it represents a significant global health and economic burden. The newly emerged coronavirus disease caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the primary reason for the COVID-19 global pandemic. According to recent global figures, COVID-19 has caused approximately 243.3 million illnesses and 4.9 million deaths. Several human cell receptors are involved in the virus identification of the host cells and entering them. Hence, understanding how the virus binds to host-cell receptors is crucial for developing antiviral treatments and vaccines. The current work aimed to determine the multiple host-cell receptors that bind with SARS-CoV-2 and other human coronaviruses for the purpose of cell entry. Extensive research is needed using neutralizing antibodies, natural chemicals, and therapeutic peptides to target those host-cell receptors in extremely susceptible individuals. More research is needed to map SARS-CoV-2 cell entry pathways in order to identify potential viral inhibitors.


Subject(s)
Coronavirus/metabolism , Host Microbial Interactions/physiology , Receptors, Coronavirus/metabolism , Antibodies, Neutralizing , Antiviral Agents/pharmacology , COVID-19 , Coronavirus/pathogenicity , Humans , Receptors, Coronavirus/physiology , Receptors, Virus/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization/drug effects
15.
Science ; 374(6573): 1353-1360, 2021 Dec 10.
Article in English | MEDLINE | ID: covidwho-1483980

ABSTRACT

The Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has outcompeted previously prevalent variants and become a dominant strain worldwide. We report the structure, function, and antigenicity of its full-length spike (S) trimer as well as those of the Gamma and Kappa variants, and compare their characteristics with the G614, Alpha, and Beta variants. Delta S can fuse membranes more efficiently at low levels of cellular receptor angiotensin converting enzyme 2 (ACE2), and its pseudotyped viruses infect target cells substantially faster than the other five variants, possibly accounting for its heightened transmissibility. Each variant shows different rearrangement of the antigenic surface of the amino-terminal domain of the S protein but only makes produces changes in the receptor binding domain (RBD), making the RBD a better target for therapeutic antibodies.


Subject(s)
Immune Evasion , Membrane Fusion , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/immunology , Antibody Affinity , Antigens, Viral/immunology , Cell Line , Epitopes/immunology , Humans , Models, Molecular , Mutation , Protein Conformation , Protein Domains , Protein Multimerization , Receptors, Coronavirus/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/physiology
16.
Eur J Clin Invest ; 52(2): e13685, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1440744

ABSTRACT

BACKGROUND: Obesity was consistently associated with a poor prognosis in patients with COVID-19. Epigenetic mechanisms were proposed as the link between obesity and comorbidities risk. AIM: To evaluate the methylation levels of angiotensin-converting enzyme 2 (ACE2) gene, the main entry receptor of SARS-CoV-2, in different depots of adipose tissue (AT) and leukocytes (PBMCs) in obesity and after weight loss therapy based on a very-low-calorie ketogenic diet (VLCKD), a balanced hypocaloric diet (HCD) or bariatric surgery (BS). MATERIALS AND METHODS: DNA methylation levels of ACE2 were extracted from our data sets generated by the hybridization of subcutaneous (SAT) (n = 32) or visceral (VAT; n = 32) adipose tissue, and PBMCs (n = 34) samples in Infinium HumanMethylation450 BeadChips. Data were compared based on the degree of obesity and after 4-6 months of weight loss either by following a nutritional or surgical treatment and correlated with ACE2 transcript levels. RESULTS: As compared with normal weight, VAT from patients with obesity showed higher ACE2 methylation levels. These differences were mirrored in PBMCs but not in SAT. The observed obesity-associated methylation of ACE2 was reversed after VLCKD and HCD but not after BS. Among the studied CpG sites, cg16734967 and cg21598868, located at the promoter, were the most affected and correlated with BMI. The observed DNA methylation pattern was inversely correlated with ACE2 expression. CONCLUSION: Obesity-related VAT shows hypermethylation and downregulation of the ACE2 gene that is mirrored in PBMCs and is restored after nutritional weight reduction therapy. The results warrant the necessity to further evaluate its implication for COVID-19 pathogenesis.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Intra-Abdominal Fat/metabolism , Leukocytes, Mononuclear/metabolism , Obesity/genetics , Receptors, Coronavirus/genetics , Subcutaneous Fat/metabolism , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/metabolism , Bariatric Surgery , COVID-19 , DNA Methylation , Diet, Ketogenic , Diet, Reducing , Female , Gene Expression Regulation , Humans , Male , Middle Aged , Obesity/metabolism , Obesity/therapy , Obesity, Morbid/genetics , Obesity, Morbid/metabolism , Obesity, Morbid/therapy , Receptors, Coronavirus/metabolism , SARS-CoV-2 , Weight Loss
17.
Viruses ; 13(8)2021 08 23.
Article in English | MEDLINE | ID: covidwho-1367926

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a global pandemic causing over 195 million infections and more than 4 million fatalities as of July 2021.To date, it has been demonstrated that a number of mutations in the spike glycoprotein (S protein) of SARS-CoV-2 variants of concern abrogate or reduce the neutralization potency of several therapeutic antibodies and vaccine-elicited antibodies. Therefore, the development of additional vaccine platforms with improved supply and logistic profile remains a pressing need. In this work, we have validated the applicability of a peptide-based strategy focused on a preventive as well as a therapeutic purpose. On the basis of the involvement of the dipeptidyl peptidase 4 (DPP4), in addition to the angiotensin converting enzyme 2 (ACE2) receptor in the mechanism of virus entry, we analyzed peptides bearing DPP4 sequences by protein-protein docking and assessed their ability to block pseudovirus infection in vitro. In parallel, we have selected and synthetized peptide sequences located within the highly conserved receptor-binding domain (RBD) of the S protein, and we found that RBD-based vaccines could better promote elicitation of high titers of neutralizing antibodies specific against the regions of interest, as confirmed by immunoinformatic methodologies and in vivo studies. These findings unveil a key antigenic site targeted by broadly neutralizing antibodies and pave the way to the design of pan-coronavirus vaccines.


Subject(s)
Dipeptidyl Peptidase 4/chemistry , Peptide Fragments/immunology , Peptide Fragments/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/drug therapy , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Dipeptidyl Peptidase 4/metabolism , Epitopes, T-Lymphocyte/immunology , Humans , Mice , Mice, Inbred BALB C , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Binding , Protein Domains , Receptors, Coronavirus/chemistry , Receptors, Coronavirus/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Internalization
18.
Viruses ; 13(8)2021 08 20.
Article in English | MEDLINE | ID: covidwho-1367922

ABSTRACT

Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019, suffer from respiratory and non-respiratory symptoms. Among these symptoms, the loss of smell has attracted considerable attention. The objectives of this study were to determine which cells are infected, what happens in the olfactory system after viral infection, and how these pathologic changes contribute to olfactory loss. For this purpose, Syrian golden hamsters were used. First, we verified the olfactory structures in the nasal cavity of Syrian golden hamsters, namely the main olfactory epithelium, the vomeronasal organ, and their cellular components. Second, we found angiotensin-converting enzyme 2 expression, a receptor protein of SARS-CoV-2, in both structures and infections of supporting, microvillar, and solitary chemosensory cells. Third, we observed pathological changes in the infected epithelium, including reduced thickness of the mucus layer, detached epithelia, indistinct layers of epithelia, infiltration of inflammatory cells, and apoptotic cells in the overall layers. We concluded that a structurally and functionally altered microenvironment influences olfactory function. We observed the regeneration of the damaged epithelium, and found multilayers of basal cells, indicating that they were activated and proliferating to reconstitute the injured epithelium.


Subject(s)
COVID-19/virology , Chemoreceptor Cells/virology , Olfactory Mucosa/virology , SARS-CoV-2 , Vomeronasal Organ/virology , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/pathology , Chemoreceptor Cells/pathology , Male , Mesocricetus , Nasal Cavity/pathology , Nasal Cavity/virology , Olfactory Mucosa/metabolism , Olfactory Mucosa/pathology , Olfactory Receptor Neurons/metabolism , Olfactory Receptor Neurons/pathology , Olfactory Receptor Neurons/virology , Receptors, Coronavirus/metabolism , Regeneration , SARS-CoV-2/isolation & purification , Vomeronasal Organ/metabolism , Vomeronasal Organ/pathology
19.
Viruses ; 13(8)2021 08 12.
Article in English | MEDLINE | ID: covidwho-1355049

ABSTRACT

The COVID-19 pandemic, caused by SARS-CoV-2, has rapidly spread to more than 222 countries and has put global public health at high risk. The world urgently needs cost-effective and safe SARS-CoV-2 vaccines, antiviral, and therapeutic drugs to control it. In this study, we engineered the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) protein and produced it in the plant Nicotiana benthamiana in a glycosylated and deglycosylated form. Expression levels of both glycosylated (gRBD) and deglycosylated (dRBD) RBD were greater than 45 mg/kg fresh weight. The purification yields were 22 mg of pure protein/kg of plant biomass for gRBD and 20 mg for dRBD, which would be sufficient for commercialization of these vaccine candidates. The purified plant-produced RBD protein was recognized by an S protein-specific monoclonal antibody, demonstrating specific reactivity of the antibody to the plant-produced RBD proteins. The SARS-CoV-2 RBD showed specific binding to angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 receptor. In mice, the plant-produced RBD antigens elicited high titers of antibodies with a potent virus-neutralizing activity. To our knowledge, this is the first report demonstrating that mice immunized with plant-produced deglycosylated RBD form elicited high titer of RBD-specific antibodies with potent neutralizing activity against SARS-CoV-2 infection. Thus, obtained data support that plant-produced glycosylated and in vivo deglycosylated RBD antigens, developed in this study, are promising vaccine candidates for the prevention of COVID-19.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Chlorocebus aethiops , Glycosylation , Male , Mice , Mice, Inbred BALB C , Neutralization Tests , Plants, Genetically Modified , Protein Binding , Protein Domains , Protein Engineering , Protein Stability , Receptors, Coronavirus/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Tobacco/genetics , Tobacco/metabolism , Vero Cells
20.
Trends Endocrinol Metab ; 32(11): 842-845, 2021 11.
Article in English | MEDLINE | ID: covidwho-1349597

ABSTRACT

The widespread extrapulmonary complications of coronavirus disease 2019 (COVID-19) have gained momentum; the pancreas is another major target for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we take a closer look into potential pathological interactions. We provide an overview of the current knowledge and understanding of SARS-CoV-2 infection of the pancreas with a special focus on pancreatic islets and propose direct, indirect, and systemic mechanisms for pancreas injury as result of the COVID-19-diabetes fatal bidirectional relationship.


Subject(s)
COVID-19/metabolism , Diabetes Mellitus/metabolism , Insulin-Secreting Cells/metabolism , Acinar Cells/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Glucagon-Secreting Cells/metabolism , Humans , Islets of Langerhans/metabolism , Pancreas/metabolism , Receptors, Coronavirus/metabolism , SARS-CoV-2/metabolism , Serine Endopeptidases/metabolism , Viral Tropism
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