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1.
Int J Mol Sci ; 21(16)2020 Aug 06.
Article in English | MEDLINE | ID: covidwho-1934101

ABSTRACT

The recently discovered 340-cavity in influenza neuraminidase (NA) N6 and N7 subtypes has introduced new possibilities for rational structure-based drug design. However, the plasticity of the 340-loop (residues 342-347) and the role of the 340-loop in NA activity and substrate binding have not been deeply exploited. Here, we investigate the mechanism of 340-cavity formation and demonstrate for the first time that seven of nine NA subtypes are able to adopt an open 340-cavity over 1.8 µs total molecular dynamics simulation time. The finding that the 340-loop plays a role in the sialic acid binding pathway suggests that the 340-cavity can function as a druggable pocket. Comparing the open and closed conformations of the 340-loop, the side chain orientation of residue 344 was found to govern the formation of the 340-cavity. Additionally, the conserved calcium ion was found to substantially influence the stability of the 340-loop. Our study provides dynamical evidence supporting the 340-cavity as a druggable hotspot at the atomic level and offers new structural insight in designing antiviral drugs.


Subject(s)
Antiviral Agents/pharmacology , Drug Development , Neuraminidase/chemistry , Orthomyxoviridae/enzymology , Binding Sites , Calcium/chemistry , Ions , Models, Molecular , Molecular Dynamics Simulation , N-Acetylneuraminic Acid/chemistry , Principal Component Analysis , Protein Structure, Secondary , Thermodynamics
2.
Nat Commun ; 13(1): 4054, 2022 07 13.
Article in English | MEDLINE | ID: covidwho-1931408

ABSTRACT

Establishment of zoonotic viruses, causing pandemics like the Spanish flu and Covid-19, requires adaptation to human receptors. Pandemic influenza A viruses (IAV) that crossed the avian-human species barrier switched from binding avian-type α2-3-linked sialic acid (2-3Sia) to human-type 2-6Sia receptors. Here, we show that this specificity switch is however less dichotomous as generally assumed. Binding and entry specificity were compared using mixed synthetic glycan gradients of 2-3Sia and 2-6Sia and by employing a genetically remodeled Sia repertoire on the surface of a Sia-free cell line and on a sialoglycoprotein secreted from these cells. Expression of a range of (mixed) 2-3Sia and 2-6Sia densities shows that non-binding human-type receptors efficiently enhanced avian IAV binding and entry provided the presence of a low density of high affinity avian-type receptors, and vice versa. Considering the heterogeneity of sialoglycan receptors encountered in vivo, hetero-multivalent binding is physiologically relevant and will impact evolutionary pathways leading to host adaptation.


Subject(s)
COVID-19 , Influenza A virus , Influenza Pandemic, 1918-1919 , Influenza, Human , Animals , Hemagglutinin Glycoproteins, Influenza Virus/metabolism , Humans , Influenza A virus/metabolism , N-Acetylneuraminic Acid/metabolism , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism , Receptors, Virus/metabolism
3.
Lab Anim ; 56(2): 201-203, 2022 04.
Article in English | MEDLINE | ID: covidwho-1832904
4.
Acta Crystallogr D Struct Biol ; 78(Pt 5): 647-657, 2022 May 01.
Article in English | MEDLINE | ID: covidwho-1831598

ABSTRACT

Sialic acids terminate many N- and O-glycans and are widely distributed on cell surfaces. There are a diverse range of enzymes which interact with these sugars throughout the tree of life. They can act as receptors for influenza and specific betacoronaviruses in viral binding and their cleavage is important in virion release. Sialic acids are also exploited by both commensal and pathogenic bacteria for nutrient acquisition. A common modification of sialic acid is 9-O-acetylation, which can limit the action of sialidases. Some bacteria, including human endosymbionts, employ esterases to overcome this modification. However, few bacterial sialic acid 9-O-acetylesterases (9-O-SAEs) have been structurally characterized. Here, the crystal structure of a 9-O-SAE from Phocaeicola vulgatus (PvSAE) is reported. The structure of PvSAE was determined to resolutions of 1.44 and 2.06 Šusing crystals from two different crystallization conditions. Structural characterization revealed PvSAE to be a dimer with an SGNH fold, named after the conserved sequence motif of this family, and a Ser-His-Asp catalytic triad. These structures also reveal flexibility in the most N-terminal α-helix, which provides a barrier to active-site accessibility. Biochemical assays also show that PvSAE deacetylates both mucin and the acetylated chromophore para-nitrophenyl acetate. This structural and biochemical characterization of PvSAE furthers the understanding of 9-O-SAEs and may aid in the discovery of small molecules targeting this class of enzyme.


Subject(s)
Acetylesterase , N-Acetylneuraminic Acid , Acetylation , Acetylesterase/chemistry , Acetylesterase/metabolism , Bacteria/metabolism , Bacteroides , Carboxylic Ester Hydrolases , Humans , N-Acetylneuraminic Acid/metabolism , Sialic Acids/metabolism
5.
Nat Commun ; 13(1): 2564, 2022 05 10.
Article in English | MEDLINE | ID: covidwho-1830056

ABSTRACT

The recent emergence of highly transmissible SARS-CoV-2 variants illustrates the urgent need to better understand the molecular details of the virus binding to its host cell and to develop anti-viral strategies. While many studies focused on the role of the angiotensin-converting enzyme 2 receptor in the infection, others suggest the important role of cell attachment factors such as glycans. Here, we use atomic force microscopy to study these early binding events with the focus on the role of sialic acids (SA). We show that SARS-CoV-2 binds specifically to 9-O-acetylated-SA with a moderate affinity, supporting its role as an attachment factor during virus landing to cell host surfaces. For therapeutic purposes and based on this finding, we have designed novel blocking molecules with various topologies and carrying a controlled number of SA residues, enhancing affinity through a multivalent effect. Inhibition assays show that the AcSA-derived glycoclusters are potent inhibitors of cell binding and infectivity, offering new perspectives in the treatment of SARS-CoV-2 infection.


Subject(s)
COVID-19 , SARS-CoV-2 , Binding Sites , COVID-19/drug therapy , Humans , N-Acetylneuraminic Acid , Protein Binding , Sialic Acids/metabolism , Spike Glycoprotein, Coronavirus/metabolism
6.
Cell Mol Immunol ; 19(5): 577-587, 2022 05.
Article in English | MEDLINE | ID: covidwho-1830043

ABSTRACT

Neutrophil extracellular traps (NETs) can capture and kill viruses, such as influenza viruses, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV), thus contributing to host defense. Contrary to our expectation, we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2, as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse model. The histone H3 or H4 selectively binds to subunit 2 of the spike (S) protein, as shown by a biochemical binding assay, surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino acids. Sialic acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S protein. Moreover, histones enhance cell-cell fusion. Finally, treatment with an inhibitor of NETosis, histone H3 or H4, or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse model. These findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Histones , Mice , N-Acetylneuraminic Acid , Protein Subunits/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Virus Internalization
7.
Viruses ; 14(5)2022 04 21.
Article in English | MEDLINE | ID: covidwho-1822442

ABSTRACT

A canine coronavirus (CCoV) has now been reported from two independent human samples from Malaysia (respiratory, collected in 2017-2018; CCoV-HuPn-2018) and Haiti (urine, collected in 2017); these two viruses were nearly genetically identical. In an effort to identify any novel adaptations associated with this apparent shift in tropism we carried out detailed evolutionary analyses of the spike gene of this virus in the context of related Alphacoronavirus 1 species. The spike 0-domain retains homology to CCoV2b (enteric infections) and Transmissible Gastroenteritis Virus (TGEV; enteric and respiratory). This domain is subject to relaxed selection pressure and an increased rate of molecular evolution. It contains unique amino acid substitutions, including within a region important for sialic acid binding and pathogenesis in TGEV. Overall, the spike gene is extensively recombinant, with a feline coronavirus type II strain serving a prominent role in the recombinant history of the virus. Molecular divergence time for a segment of the gene where temporal signal could be determined, was estimated at around 60 years ago. We hypothesize that the virus had an enteric origin, but that it may be losing that particular tropism, possibly because of mutations in the sialic acid binding region of the spike 0-domain.


Subject(s)
Coronavirus, Canine , Animals , Cats , Dogs , N-Acetylneuraminic Acid , Spike Glycoprotein, Coronavirus/genetics , Tropism , Zoonoses
8.
Eur Heart J Cardiovasc Pharmacother ; 8(4): 392-401, 2022 Jun 08.
Article in English | MEDLINE | ID: covidwho-1746904

ABSTRACT

AIMS: The aim of this study was to investigate the effects of Neuraminidase inhibitors (NI) on COVID-19 in a retrospective study. METHODS AND RESULTS: The study included an overall COVID-19 patients (n = 3267) and a 1:1 propensity score-matched patients (n = 972). The levels of plasma N-acetylneuraminic acid and neuraminidase expression were further evaluated in a panel of hospitalized and 1-month post-infection recovered COVID-19 subjects. The mortality rate in the overall patients was 9.6% (313/3267) and 9.2% (89/972) in the propensity-score matched patients. The NI treatment lowered the mortality rate (5.7% vs. 10.3%) and the critically ill conversion rate (14.1% vs. 19.7%) compare to those in the non-NI group in the overall patients and evaluated in the propensity score-matched patients when applying the multivariate Cox model for adjusting imbalanced confounding factors. Furthermore, NI treatment was associated with attenuated cytokine storm levels and acute heart injury but not liver or kidney injuries. Further analysis in a small panel of patients found the levels of N-acetylneuraminic acid and neuraminidase (dominantly the NEU3 isoform) were elevated in the hospitalized COVID-19 subjects and recovered at the 1-month post-infection stage, suggesting increasing desialylation in COVID-19 patients. CONCLUSION: These results suggest that NI treatment is associated with decreased mortality in COVID-19 subjects, especially for those subjects with acute heart injury.


Subject(s)
Antiviral Agents , COVID-19 , Neuraminidase , Antiviral Agents/therapeutic use , COVID-19/drug therapy , COVID-19/mortality , Cardiovascular Diseases/virology , Humans , N-Acetylneuraminic Acid , Neuraminidase/antagonists & inhibitors , Retrospective Studies
9.
Int J Mol Sci ; 23(5)2022 Feb 25.
Article in English | MEDLINE | ID: covidwho-1736943

ABSTRACT

Rouleaux (stacked clumps) of red blood cells (RBCs) observed in the blood of COVID-19 patients in three studies call attention to the properties of several enveloped virus strains dating back to seminal findings of the 1940s. For COVID-19, key such properties are: (1) SARS-CoV-2 binds to RBCs in vitro and also in the blood of COVID-19 patients; (2) although ACE2 is its target for viral fusion and replication, SARS-CoV-2 initially attaches to sialic acid (SA) terminal moieties on host cell membranes via glycans on its spike protein; (3) certain enveloped viruses express hemagglutinin esterase (HE), an enzyme that releases these glycan-mediated bindings to host cells, which is expressed among betacoronaviruses in the common cold strains but not the virulent strains, SARS-CoV, SARS-CoV-2 and MERS. The arrangement and chemical composition of the glycans at the 22 N-glycosylation sites of SARS-CoV-2 spike protein and those at the sialoglycoprotein coating of RBCs allow exploration of specifics as to how virally induced RBC clumping may form. The in vitro and clinical testing of these possibilities can be sharpened by the incorporation of an existing anti-COVID-19 therapeutic that has been found in silico to competitively bind to multiple glycans on SARS-CoV-2 spike protein.


Subject(s)
COVID-19/metabolism , Erythrocytes/metabolism , SARS-CoV-2/metabolism , Sialoglycoproteins/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Basigin/metabolism , Binding Sites , COVID-19/virology , Glycosylation , Hemagglutination , Hemagglutinins, Viral/metabolism , Humans , N-Acetylneuraminic Acid/metabolism , Polysaccharides/metabolism , Protein Binding , SARS-CoV-2/physiology , Viral Fusion Proteins/metabolism , Virus Internalization
10.
Angew Chem Int Ed Engl ; 61(18): e202201432, 2022 04 25.
Article in English | MEDLINE | ID: covidwho-1729097

ABSTRACT

The interaction of the SARS CoV2 spike glycoprotein with two sialic acid-containing trisaccharides (α2,3 and α2,6 sialyl N-acetyllactosamine) has been demonstrated by NMR. The NMR-based distinction between the signals of those sialic acids in the glycans covalently attached to the spike protein and those belonging to the exogenous α2,3 and α2,6 sialyl N-acetyllactosamine ligands has been achieved by synthesizing uniformly 13 C-labelled trisaccharides at the sialic acid and galactose moieties. STD-1 H,13 C-HSQC NMR experiments elegantly demonstrate the direct interaction of the sialic acid residues of both trisaccharides with additional participation of the galactose moieties, especially for the α2,3-linked analogue. Additional experiments with the spike protein in the presence of a specific antibody for the N-terminal domain and with the isolated receptor binding and N-terminal domains of the spike protein unambiguously show that the sialic acid binding site is located at the N-terminal domain.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Binding Sites , Galactose , Humans , N-Acetylneuraminic Acid/chemistry , SARS-CoV-2 , Sialic Acids/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Trisaccharides
11.
Int J Mol Sci ; 22(16)2021 Aug 05.
Article in English | MEDLINE | ID: covidwho-1662663

ABSTRACT

Coxsackievirus A24 variant (CVA24v) is the primary causative agent of the highly contagious eye infection designated acute hemorrhagic conjunctivitis (AHC). It is solely responsible for two pandemics and several recurring outbreaks of the disease over the last decades, thus affecting millions of individuals throughout the world. To date, no antiviral agents or vaccines are available for combating this disease, and treatment is mainly supportive. CVA24v utilizes Neu5Ac-containing glycans as attachment receptors facilitating entry into host cells. We have previously reported that pentavalent Neu5Ac conjugates based on a glucose-scaffold inhibit CVA24v infection of human corneal epithelial cells. In this study, we report on the design and synthesis of scaffold-replaced pentavalent Neu5Ac conjugates and their effect on CVA24v cell transduction and the use of cryogenic electron microscopy (cryo-EM) to study the binding of these multivalent conjugates to CVA24v. The results presented here provide insights into the development of Neu5Ac-based inhibitors of CVA24v and, most significantly, the first application of cryo-EM to study the binding of a multivalent ligand to a lectin.


Subject(s)
Antiviral Agents/pharmacology , Coxsackievirus Infections/diet therapy , Enterovirus C, Human/drug effects , N-Acetylneuraminic Acid/pharmacology , Conjunctivitis, Acute Hemorrhagic/drug therapy , Conjunctivitis, Acute Hemorrhagic/metabolism , Conjunctivitis, Acute Hemorrhagic/virology , Coxsackievirus Infections/metabolism , Coxsackievirus Infections/virology , Glucose/metabolism , Humans , Lectins/metabolism , Ligands , Polysaccharides/metabolism , Receptors, Virus/metabolism
12.
Viruses ; 13(12)2021 12 06.
Article in English | MEDLINE | ID: covidwho-1555020

ABSTRACT

Porcine deltacoronavirus (PDCoV) is a novel coronavirus that causes diarrhea in nursing piglets. Studies showed that PDCoV uses porcine aminopeptidase N (pAPN) as an entry receptor, but the infection of pAPN-knockout cells or pigs with PDCoV revealed that pAPN might be not a critical functional receptor, implying there exists an unidentified receptor involved in PDCoV infection. Herein, we report that sialic acid (SA) can act as an attachment receptor for PDCoV invasion and facilitate its infection. We first demonstrated that the carbohydrates destroyed on the cell membrane using NaIO4 can alleviate the susceptibility of cells to PDCoV. Further study showed that the removal of SA, a typical cell-surface carbohydrate, could influence the PDCoV infectivity to the cells significantly, suggesting that SA was involved in the infection. The results of plaque assay and Western blotting revealed that SA promoted PDCoV infection by increasing the number of viruses binding to SA on the cell surface during the adsorption phase, which was also confirmed by atomic force microscopy at the microscopic level. In in vivo experiments, we found that the distribution levels of PDCoV and SA were closely relevant in the swine intestine, which contains huge amount of trypsin. We further confirmed that SA-binding capacity to PDCoV is related to the pre-treatment of PDCoV with trypsin. In conclusion, SA is a novel attachment receptor for PDCoV infection to enhance its attachment to cells, which is dependent on the pre-treatment of trypsin on PDCoV. This study paves the way for dissecting the mechanisms of PDCoV-host interactions and provides new strategies to control PDCoV infection.


Subject(s)
Deltacoronavirus/physiology , N-Acetylneuraminic Acid/metabolism , Receptors, Virus/metabolism , Trypsin/metabolism , Virus Attachment , Animals , Carbohydrates , Cell Line , Cell Membrane/metabolism , Cell Membrane/virology , Coronavirus Infections/veterinary , Coronavirus Infections/virology , Deltacoronavirus/drug effects , Host-Pathogen Interactions , Intestines/metabolism , Intestines/virology , Periodic Acid/pharmacology , Swine , Swine Diseases/virology , Trypsin/pharmacology
13.
Tissue Cell ; 74: 101679, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1521561

ABSTRACT

BACKGROUND: It is known that SARS-CoV-2 mostly infects the respiratory system causing pneumonia; although it can also affect the gastrointestinal tract (GIT), which covered with a bi-layer of mucus rich in glycosylated proteins that terminated by sialic acid. Therefore; this study aimed to evaluate serum total sialic acid (TSA) in moderate COVID-19 patients with and without GIT manifestations. METHODS: A total of 161 moderate COVID-19 patients without and with GIT manifestations and 50 controls were enrolled into our study. Serum electrolytes levels were measured by using colorimetric or turbidmetric commercial assay kits, while the level of serum TSA was measured by using a commercial ELISA kit. RESULTS: Our results showed that serum TSA level was highly significantly increased in moderate COVID-19 patients with GIT manifestations (81.43 ± 8.91) when compared with controls (61.24 ± 6.41) or even moderate COVID-19 patients without GIT manifestations (69.46 ± 7.03). ROC curve analysis showed that AUC for TSA is 0.84 with 76.2 % sensitivity and 73.7 % specificity in discrimination between moderate COVID-19 patients with and without GIT manifestations. Serum potassium and sodium levels were highly significantly decreased in moderate COVID-19 patients with GIT manifestations when compared with controls or even moderate COVID-19 patients without GIT manifestations; while serum calcium level was found to be significantly decreased in moderate COVID-19 patients with GIT manifestations when compared with controls. CONCLUSION: Finally, we can conclude that SA plays a crucial role in the pathogenesis of GIT complications associated with COVID-19 and could be a potential biomarker for the COVID-19 gastrointestinal complications.


Subject(s)
COVID-19/pathology , Gastrointestinal Tract/pathology , N-Acetylneuraminic Acid/blood , Adult , Biomarkers/blood , Enzyme-Linked Immunosorbent Assay , Female , Gastrointestinal Tract/virology , Humans , Male , Middle Aged , Mucus/metabolism , Mucus/virology , SARS-CoV-2
15.
Sci Rep ; 11(1): 20428, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1469984

ABSTRACT

Glycosylation is the most common post-translational modification and has myriad of biological functions. However, glycan analysis has always been a challenge. Here, we would like to present new techniques for glycan fingerprinting based on enzymatic fluorescent labeling and gel electrophoresis. The method is illustrated on SARS2 spike (S) glycoproteins. SARS2, a novel coronavirus and the causative agent of the COVID-19 pandemic, has had significant social and economic impacts since the end of 2019. To obtain the N-glycan fingerprint of an S protein, glycans released from the protein are first labeled through enzymatic incorporation of fluorophore-conjugated sialic acid or fucose, then separated by SDS-PAGE, and finally visualized with a fluorescent imager. To identify the labeled glycans of a fingerprint, glycan standards and glycan ladders are enzymatically generated and run alongside the samples as references. By comparing the mobility of a labeled glycan to that of a glycan standard, the identity of glycans maybe determined. O-glycans can also be fingerprinted. Due to the lack of an enzyme for broad O-glycan release, O-glycans on the S protein can be labeled with fluorescent sialic acid and digested with trypsin to obtain labeled glycan peptides that are then separated by gel electrophoresis. Glycan fingerprinting could serve as a quick method for globally assessing the glycosylation of a specific glycoprotein.


Subject(s)
COVID-19/virology , Polysaccharides/analysis , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Carbocyanines/chemistry , Electrophoresis, Polyacrylamide Gel , Fluorescent Dyes/chemistry , Fucose/analogs & derivatives , Glycosylation , Humans , N-Acetylneuraminic Acid/analogs & derivatives , Optical Imaging
17.
J Oral Biosci ; 63(4): 416-419, 2021 12.
Article in English | MEDLINE | ID: covidwho-1401640

ABSTRACT

Salivary glands are considered important targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recent evidence suggests that along with angiotensin converting enzyme 2, certain cell surface sialic acids (Sia) may function as receptors for binding SARS-CoV-2 spike protein. Over 50 forms of Sia have been identified in nature, with N-acetylneuraminic acid (Neu5Ac) being the most abundant. We explored the Human Protein Atlas repository to analyze important enzymes in Neu5Ac biosynthesis and propose a hypothesis that further highlights the significance of salivary glands in coronavirus disease 19 (COVID-19). This work may facilitate research into targeted drug therapies for COVID-19.


Subject(s)
COVID-19 , Humans , N-Acetylneuraminic Acid , SARS-CoV-2 , Sialic Acids , Spike Glycoprotein, Coronavirus , Virus Attachment
18.
J Control Release ; 337: 612-627, 2021 09 10.
Article in English | MEDLINE | ID: covidwho-1330947

ABSTRACT

Neutrophils, the most abundant leukocytes in human peripheral blood, are important effector cells that mediate the inflammatory response. During neutrophil dysfunction, excessive activation and uncontrolled infiltration are the core processes in the progression of inflammation-related diseases, including severe coronavirus disease-19 (COVID-19), sepsis, etc. Herein, we used sialic acid-modified liposomal doxorubicin (DOX-SAL) to selectively target inflammatory neutrophils in the peripheral blood and deliver DOX intracellularly, inducing neutrophil apoptosis, blocking neutrophil migration, and inhibiting the inflammatory response. Strong selectivity resulted from the specific affinity between SA and L-selectin, which is highly expressed on inflammatory neutrophil membranes. In inflammation models of acute lung inflammation/injury (ALI), sepsis, and rheumatoid arthritis (RA), DOX-SAL suppressed the inflammatory response, increased the survival of mice, and delayed disease progression, respectively. Moreover, DOX-SAL restored immune homeostasis in the body, without side effects. We have presented a targeted nanocarrier drug delivery system that can block the recruitment of inflammatory neutrophils, enabling specific inhibition of the core disease process and the potential to treat multiple diseases with a single drug. This represents a revolutionary treatment strategy for inflammatory diseases caused by inappropriate neutrophil activation.


Subject(s)
COVID-19 , Neutrophils , Animals , Doxorubicin , Humans , Inflammation/drug therapy , Mice , N-Acetylneuraminic Acid , SARS-CoV-2
19.
Virology ; 562: 142-148, 2021 10.
Article in English | MEDLINE | ID: covidwho-1331288

ABSTRACT

SARS-CoV, MERS-CoV, and potentially SARS-CoV-2 emerged as novel human coronaviruses following cross-species transmission from animal hosts. Although the receptor binding characteristics of human coronaviruses are well documented, the role of carbohydrate binding in addition to recognition of proteinaceous receptors has not been fully explored. Using natural glycan microarray technology, we identified N-glycans in the human lung that are recognized by various human and animal coronaviruses. All viruses tested, including SARS-CoV-2, bound strongly to a range of phosphorylated, high mannose N-glycans and to a very specific set of sialylated structures. Examination of two linked strains, human CoV OC43 and bovine CoV Mebus, reveals shared binding to the sialic acid form Neu5Gc (not found in humans), supporting the evidence for cross-species transmission of the bovine strain. Our findings, revealing robust recognition of lung glycans, suggest that these receptors could play a role in the initial stages of coronavirus attachment and entry.


Subject(s)
COVID-19/virology , Host Microbial Interactions/physiology , Middle East Respiratory Syndrome Coronavirus/metabolism , Polysaccharides/metabolism , SARS-CoV-2/metabolism , Animals , Cattle , Humans , Lung/metabolism , Mannose/chemistry , Middle East Respiratory Syndrome Coronavirus/physiology , N-Acetylneuraminic Acid/chemistry , Phosphorylation , Protein Array Analysis , Protein Binding , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/physiology
20.
Nat Chem ; 13(5): 496-503, 2021 05.
Article in English | MEDLINE | ID: covidwho-1145994

ABSTRACT

The transmission of viruses from animal reservoirs to humans poses major threats to public health. Preparedness for future zoonotic outbreaks requires a fundamental understanding of how viruses of animal origin have adapted to binding to a cell surface component and/or receptor of the new host. Here we report on the specificities of human and animal viruses that engage with O-acetylated sialic acid, which include betacoronaviruses, toroviruses and influenza C and D viruses. Key to these studies was the development of a chemoenzymatic methodology that can provide almost any sialate-acetylation pattern. A collection of O-acetylated sialoglycans was printed as a microarray for the determination of receptor specificity. These studies showed host-specific patterns of receptor recognition and revealed that three distinct human respiratory viruses uniquely bind 9-O-acetylated α2,8-linked disialoside. Immunofluorescence and cell entry studies support that such a glycotope as part of a ganglioside is a functional receptor for human coronaviruses.


Subject(s)
N-Acetylneuraminic Acid/chemistry , Respiratory Tract Infections/virology , Viruses/pathogenicity , Humans , Transfection
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