Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 11 de 11
Filter
1.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-335224

ABSTRACT

The Omicron subvariant BA.2 has become the dominant circulating strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in many countries. We have characterized structural, functional and antigenic properties of the full-length BA.2 spike (S) protein and compared replication of the authentic virus in cell culture and animal model with previously prevalent variants. BA.2 S can fuse membranes more efficiently than Omicron BA.1, mainly due to lack of a BA.1-specific mutation that may retard the receptor engagement, but still less efficiently than other variants. Both BA.1 and BA.2 viruses replicated substantially faster in animal lungs than the early G614 (B.1) strain in the absence of pre-existing immunity, possibly explaining the increased transmissibility despite their functionally compromised spikes. As in BA.1, mutations in the BA.2 S remodel its antigenic surfaces leading to strong resistance to neutralizing antibodies. These results suggest that both immune evasion and replicative advantage may contribute to the heightened transmissibility for the Omicron subvariants.

2.
Proc Natl Acad Sci U S A ; 119(18): e2201433119, 2022 05 03.
Article in English | MEDLINE | ID: covidwho-1815698

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike is a trimer of S1/S2 heterodimers with three receptor-binding domains (RBDs) at the S1 subunit for human angiotensin-converting enzyme 2 (hACE2). Due to their small size, nanobodies can recognize protein cavities that are not accessible to conventional antibodies. To isolate high-affinity nanobodies, large libraries with great diversity are highly desirable. Dromedary camels (Camelus dromedarius) are natural reservoirs of coronaviruses like Middle East respiratory syndrome CoV (MERS-CoV) that are transmitted to humans. Here, we built large dromedary camel VHH phage libraries to isolate nanobodies that broadly neutralize SARS-CoV-2 variants. We isolated two VHH nanobodies, NCI-CoV-7A3 (7A3) and NCI-CoV-8A2 (8A2), which have a high affinity for the RBD via targeting nonoverlapping epitopes and show broad neutralization activity against SARS-CoV-2 and its emerging variants of concern. Cryoelectron microscopy (cryo-EM) complex structures revealed that 8A2 binds the RBD in its up mode with a long CDR3 loop directly involved in the ACE2 binding residues and that 7A3 targets a deeply buried region that uniquely extends from the S1 subunit to the apex of the S2 subunit regardless of the conformational state of the RBD. At a dose of ≥5 mg/kg, 7A3 efficiently protected transgenic mice expressing hACE2 from the lethal challenge of variants B.1.351 or B.1.617.2, suggesting its therapeutic use against COVID-19 variants. The dromedary camel VHH phage libraries could be helpful as a unique platform ready for quickly isolating potent nanobodies against future emerging viruses.


Subject(s)
COVID-19 , Single-Domain Antibodies , Animals , Camelus , Humans , Mice , SARS-CoV-2/genetics , Single-Domain Antibodies/genetics
3.
Sci Rep ; 12(1): 6294, 2022 04 15.
Article in English | MEDLINE | ID: covidwho-1805651

ABSTRACT

Spike-mediated entry of SARS-CoV-2 into human airway epithelial cells is an attractive therapeutic target for COVID-19. In addition to protein receptors, the SARS-CoV-2 spike (S) protein also interacts with heparan sulfate, a negatively charged glycosaminoglycan (GAG) attached to certain membrane proteins on the cell surface. This interaction facilitates the engagement of spike with a downstream receptor to promote viral entry. Here, we show that Mitoxantrone, an FDA-approved topoisomerase inhibitor, targets a heparan sulfate-spike complex to compromise the fusogenic function of spike in viral entry. As a single agent, Mitoxantrone inhibits the infection of an authentic SARS-CoV-2 strain in a cell-based model and in human lung EpiAirway 3D tissues. Gene expression profiling supports the plasma membrane as a major target of Mitoxantrone but also underscores an undesired activity targeting nucleosome dynamics. We propose that Mitoxantrone analogs bearing similar heparan sulfate-binding activities but with reduced affinity for DNA topoisomerases may offer an alternative therapy to overcome breakthrough infections in the post-vaccine era.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , COVID-19/drug therapy , Heparin/metabolism , Heparitin Sulfate/metabolism , Humans , Mitoxantrone/pharmacology , Protein Binding , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism
4.
Nat Commun ; 12(1): 6559, 2021 11 12.
Article in English | MEDLINE | ID: covidwho-1514414

ABSTRACT

SARS-CoV-2 variants of concern (VOC) B.1.1.7 (alpha) and B.1.351 (beta) show increased transmissibility and enhanced antibody neutralization resistance. Here we demonstrate in K18-hACE2 transgenic mice that B.1.1.7 and B.1.351 are 100-fold more lethal than the original SARS-CoV-2 bearing 614D. B.1.1.7 and B.1.351 cause more severe organ lesions in K18-hACE2 mice than early SARS-CoV-2 strains bearing 614D or 614G, with B.1.1.7 and B.1.351 infection resulting in distinct tissue-specific cytokine signatures, significant D-dimer depositions in vital organs and less pulmonary hypoxia signaling before death. However, K18-hACE2 mice with prior infection of early SARS-CoV-2 strains or intramuscular immunization of viral spike or receptor binding domain are resistant to the lethal reinfection of B.1.1.7 or B.1.351, despite having reduced neutralization titers against these VOC than early strains. Our results thus distinguish pathogenic patterns in K18-hACE2 mice caused by B.1.1.7 and B.1.351 infection from those induced by early SARS-CoV-2 strains, and help inform potential medical interventions for combating COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/virology , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19/genetics , COVID-19/pathology , Cell Line , Chlorocebus aethiops , Cytokines/immunology , Disease Models, Animal , Female , Fibrin Fibrinogen Degradation Products/immunology , Hypoxia/virology , Lung/metabolism , Lung/pathology , Lung/virology , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , SARS-CoV-2/classification , SARS-CoV-2/isolation & purification , SARS-CoV-2/pathogenicity
5.
Nat Commun ; 12(1): 3623, 2021 06 15.
Article in English | MEDLINE | ID: covidwho-1270656

ABSTRACT

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) urgently needs an effective cure. 3CL protease (3CLpro) is a highly conserved cysteine proteinase that is indispensable for coronavirus replication, providing an attractive target for developing broad-spectrum antiviral drugs. Here we describe the discovery of myricetin, a flavonoid found in many food sources, as a non-peptidomimetic and covalent inhibitor of the SARS-CoV-2 3CLpro. Crystal structures of the protease bound with myricetin and its derivatives unexpectedly revealed that the pyrogallol group worked as an electrophile to covalently modify the catalytic cysteine. Kinetic and selectivity characterization together with theoretical calculations comprehensively illustrated the covalent binding mechanism of myricetin with the protease and demonstrated that the pyrogallol can serve as an electrophile warhead. Structure-based optimization of myricetin led to the discovery of derivatives with good antiviral activity and the potential of oral administration. These results provide detailed mechanistic insights into the covalent mode of action by pyrogallol-containing natural products and a template for design of non-peptidomimetic covalent inhibitors against 3CLpros, highlighting the potential of pyrogallol as an alternative warhead in design of targeted covalent ligands.


Subject(s)
Coronavirus 3C Proteases/drug effects , Pyrogallol/chemistry , Pyrogallol/isolation & purification , Pyrogallol/pharmacology , SARS-CoV-2/drug effects , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus Papain-Like Proteases , Drug Design , Flavonoids , HEK293 Cells , Humans , Kinetics , Ligands , Molecular Dynamics Simulation , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/chemistry
6.
J Med Virol ; 93(7): 4570-4575, 2021 07.
Article in English | MEDLINE | ID: covidwho-1263108

ABSTRACT

Inpatient coronavirus disease 2019 (COVID-19) cases present enormous costs to patients and health systems in the United States. Many hospitalized patients may continue testing COVID-19 positive even after the resolution of symptoms. Thus, a pressing concern for clinicians is the safety of discharging these asymptomatic patients if they have any remaining infectivity. This case report explores the viral viability in a patient with persistent COVID-19 over the course of a 2-month hospitalization. Positive nasopharyngeal swab samples were collected and isolated in the laboratory and analyzed by quantitative reverse-transcription polymerase chain reactions (qRT-PCR), and serology was tested for neutralizing antibodies throughout the hospitalization period. The patient experienced waning symptoms by hospital day 40 and had no viable virus growth by hospital day 41, suggesting no risk of infectivity, despite positive RT-PCR results which prolonged his hospital stay. Notably, this case showed infectivity for at least 24 days after disease onset, which is longer than the discontinuation of transmission-based precautions recommended by the Center for Disease Control and Prevention. Thus, our findings suggest that the timeline for discontinuing transmission-based precautions may need to be extended for patients with severe and prolonged COVID-19 disease. Additional large-scale studies are needed to draw definitive conclusions on the appropriate clinical management for these patients. ​.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Nucleic Acid Testing , COVID-19/diagnosis , Virus Shedding/physiology , Aged , Asymptomatic Infections , Humans , Male , RNA, Viral/analysis , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , SARS-CoV-2/immunology
7.
J Med Chem ; 65(4): 2794-2808, 2022 02 24.
Article in English | MEDLINE | ID: covidwho-1192017

ABSTRACT

A novel series of peptidomimetic aldehydes was designed and synthesized to target 3C protease (3Cpro) of enterovirus 71 (EV71). Most of the compounds exhibited high antiviral activity, and among them, compound 18p demonstrated potent enzyme inhibitory activity and broad-spectrum antiviral activity on a panel of enteroviruses and rhinoviruses. The crystal structure of EV71 3Cpro in complex with 18p determined at a resolution of 1.2 Å revealed that 18p covalently linked to the catalytic Cys147 with an aldehyde group. In addition, these compounds also exhibited good inhibitory activity against the 3CLpro and the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially compound 18p (IC50 = 0.034 µM, EC50 = 0.29 µM). According to our previous work, these compounds have no reasons for concern regarding acute toxicity. Compared with AG7088, compound 18p also exhibited good pharmacokinetic properties and more potent anticoronavirus activity, making it an excellent lead for further development.


Subject(s)
Aldehydes/pharmacology , Antiviral Agents/pharmacology , Cysteine Proteinase Inhibitors/pharmacology , Enterovirus/drug effects , Peptidomimetics/pharmacology , SARS-CoV-2/drug effects , Aldehydes/chemical synthesis , Aldehydes/chemistry , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Cell Line , Chlorocebus aethiops , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/isolation & purification , Coronavirus 3C Proteases/metabolism , Cysteine Proteinase Inhibitors/chemical synthesis , Cysteine Proteinase Inhibitors/chemistry , Dose-Response Relationship, Drug , Drug Design , Humans , Male , Mice , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Peptidomimetics/chemical synthesis , Peptidomimetics/chemistry , Structure-Activity Relationship
8.
Vaccines (Basel) ; 9(4)2021 Apr 14.
Article in English | MEDLINE | ID: covidwho-1187070

ABSTRACT

While the scientific community has been focusing on combating novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is responsible for the current COVID-19 pandemic, we also want to draw your attention to this Special Issue of Vaccines entitled "Influenza Virus and Vaccine Development" [...].

9.
Bioorg Chem ; 110: 104767, 2021 05.
Article in English | MEDLINE | ID: covidwho-1108078

ABSTRACT

SARS-CoV-2 is the pathogen that caused the global COVID-19 outbreak in 2020. Promising progress has been made in developing vaccines and antiviral drugs. Antivirals medicines are necessary complements of vaccines for post-infection treatment. The main protease (Mpro) is an extremely important protease in the reproduction process of coronaviruses which cleaves pp1ab over more than 11 cleavage sites. In this work, two active main protease inhibitors were found via docking-based virtual screening and bioassay. The IC50 of compound VS10 was 0.20 µM, and the IC50 of compound VS12 was 1.89 µM. The finding in this work can be helpful to understand the interactions of main protease and inhibitors. The active candidates could be potential lead compounds for future drug design.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Drug Discovery , Protease Inhibitors/pharmacology , SARS-CoV-2/enzymology , Drug Evaluation, Preclinical , Humans , Molecular Docking Simulation , Protease Inhibitors/chemistry
10.
Med Res Rev ; 41(4): 1965-1998, 2021 07.
Article in English | MEDLINE | ID: covidwho-1032327

ABSTRACT

The emergence of a variety of coronaviruses (CoVs) in the last decades has posed huge threats to human health. Especially, the ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to more than 70 million infections and over 1.6 million of deaths worldwide in the past few months. None of the efficacious antiviral agents against human CoVs have been approved yet. 3C-like protease (3CLpro ) is an attractive target for antiviral intervention due to its essential role in processing polyproteins translated from viral RNA, and its conserved structural feature and substrate specificity among CoVs in spite of the sequence variation. This review focuses on all available crystal structures of 12 CoV 3CLpro s and their inhibitors, and intends to provide a comprehensive understanding of this protease from multiple aspects including its structural features, substrate specificity, inhibitor binding modes, and more importantly, to recapitulate the similarity and diversity among different CoV 3CLpro s and the structure-activity relationship of various types of inhibitors. Such an attempt could gain a deep insight into the inhibition mechanisms and drive future structure-based drug discovery targeting 3CLpro s.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Drug Discovery , Binding Sites , COVID-19/drug therapy , Drug Design , Humans , Protein Conformation , Protein Structure, Quaternary , SARS-CoV-2/drug effects , Structure-Activity Relationship , Substrate Specificity
11.
Acta Pharmacol Sin ; 41(9): 1167-1177, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-691161

ABSTRACT

Human infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and there is no cure currently. The 3CL protease (3CLpro) is a highly conserved protease which is indispensable for CoVs replication, and is a promising target for development of broad-spectrum antiviral drugs. In this study we investigated the anti-SARS-CoV-2 potential of Shuanghuanglian preparation, a Chinese traditional patent medicine with a long history for treating respiratory tract infection in China. We showed that either the oral liquid of Shuanghuanglian, the lyophilized powder of Shuanghuanglian for injection or their bioactive components dose-dependently inhibited SARS-CoV-2 3CLpro as well as the replication of SARS-CoV-2 in Vero E6 cells. Baicalin and baicalein, two ingredients of Shuanghuanglian, were characterized as the first noncovalent, nonpeptidomimetic inhibitors of SARS-CoV-2 3CLpro and exhibited potent antiviral activities in a cell-based system. Remarkably, the binding mode of baicalein with SARS-CoV-2 3CLpro determined by X-ray protein crystallography was distinctly different from those of known 3CLpro inhibitors. Baicalein was productively ensconced in the core of the substrate-binding pocket by interacting with two catalytic residues, the crucial S1/S2 subsites and the oxyanion loop, acting as a "shield" in front of the catalytic dyad to effectively prevent substrate access to the catalytic dyad within the active site. Overall, this study provides an example for exploring the in vitro potency of Chinese traditional patent medicines and effectively identifying bioactive ingredients toward a specific target, and gains evidence supporting the in vivo studies of Shuanghuanglian oral liquid as well as two natural products for COVID-19 treatment.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections , Drugs, Chinese Herbal , Flavanones , Flavonoids , Pandemics , Pneumonia, Viral , Virus Replication/drug effects , Administration, Oral , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/physiology , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/pharmacology , Enzyme Assays , Flavanones/chemistry , Flavanones/pharmacokinetics , Flavonoids/chemistry , Flavonoids/pharmacokinetics , Humans , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , SARS-CoV-2 , Vero Cells , Virus Replication/physiology
SELECTION OF CITATIONS
SEARCH DETAIL