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1.
Adv Exp Med Biol ; 1366: 101-121, 2022.
Article in English | MEDLINE | ID: covidwho-1782743

ABSTRACT

Coronaviruses (CoVs) are enveloped RNA viruses that widely exist in the environment. Several CoVs possess a strong ability to infect humans, termed as human coronavirus (HCoVs). Among seven known HCoVs, SARS-CoV-2, SARS-CoV, and MERS-CoV belong to highly pathogenic HCoVs, which can cause severe clinical symptoms and even death. Especially, the current COVID-19 pandemic severely threatens human survival and health, which emphasizes the importance of developing effective CoV vaccines and anti-CoV agents to protect humans from HCoV infections. Coronavirus entry inhibitors can block various processes in viral entry, such as receptor binding, proteolytic activation of spike protein, or virus-cell membrane fusion. Coronavirus entry inhibitors, alone or in combination with other drugs, play important roles in the treatment of coronavirus diseases. Thus, we summarize and discuss the development of coronavirus entry inhibitors in this chapter.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , COVID-19/drug therapy , Humans , Pandemics , SARS-CoV-2 , Virus Internalization
2.
Viruses ; 14(4)2022 03 22.
Article in English | MEDLINE | ID: covidwho-1753696

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by infection of SARS-CoV-2 and its variants has posed serious threats to global public health, thus calling for the development of potent and broad-spectrum antivirals. We previously designed and developed a peptide-based pan-coronavirus (CoV) fusion inhibitor, EK1, which is effective against all human CoVs (HCoV) tested by targeting the HCoV S protein HR1 domain. However, its relatively short half-life may limit its clinical use. Therefore, we designed, constructed, and expressed a recombinant protein, FL-EK1, which consists of a modified fibronectin type III domain (FN3) with albumin-binding capacity, a flexible linker, and EK1. As with EK1, we found that FL-EK1 could also effectively inhibit infection of SARS-CoV-2 and its variants, as well as HCoV-OC43. Furthermore, it protected mice from infection by the SARS-CoV-2 Delta variant and HCoV-OC43. Importantly, the half-life of FL-EK1 (30 h) is about 15.7-fold longer than that of EK1 (1.8 h). These results suggest that FL-EK1 is a promising candidate for the development of a pan-CoV fusion inhibitor-based long-acting antiviral drug for preventing and treating infection by current and future SARS-CoV-2 variants, as well as other HCoVs.


Subject(s)
COVID-19 , SARS-CoV-2 , Viral Fusion Protein Inhibitors , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Coronavirus Infections/drug therapy , Fibronectin Type III Domain , Half-Life , Mice , Recombinant Fusion Proteins , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/metabolism , Viral Fusion Protein Inhibitors/chemistry , Viral Fusion Protein Inhibitors/pharmacology
3.
Viruses ; 14(3)2022 03 06.
Article in English | MEDLINE | ID: covidwho-1732247

ABSTRACT

Our previous studies have shown that cholesterol-conjugated, peptide-based pan-coronavirus (CoV) fusion inhibitors can potently inhibit human CoV infection. However, only palmitic acid (C16)-based lipopeptide drugs have been tested clinically, suggesting that the development of C16-based lipopeptide drugs is feasible. Here, we designed and synthesized a C16-modified pan-CoV fusion inhibitor, EK1-C16, and found that it potently inhibited infection by SARS-CoV-2 and its variants of concern (VOCs), including Omicron, and other human CoVs and bat SARS-related CoVs (SARSr-CoVs). These results suggest that EK1-C16 could be further developed for clinical use to prevent and treat infection by the currently circulating MERS-CoV, SARS-CoV-2 and its VOCs, as well as any future emerging or re-emerging coronaviruses.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , COVID-19/drug therapy , Humans , Lipopeptides/pharmacology , Palmitic Acid/pharmacology , SARS-CoV-2
4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315723

ABSTRACT

The pandemic of COVID-19 caused by SARS-CoV-2 has posed serious threats to global health and economy, thus calling for the development of safe and effective vaccines. The receptor-binding domain (RBD) in the spike protein of SARS-CoV-2 is responsible for its binding to ACE2 receptor. It contains multiple dominant neutralizing epitopes and serves as an important antigen for the development of COVID-19 vaccines. Here, we showed that immunization of mice with a candidate subunit vaccine consisting of SARS-CoV-2 RBD and Fc fragment of human IgG, as an immunopotentiator, elicited high titer of RBD-specific antibodies with robust neutralizing activity against both pseudotyped and live SARS-CoV-2 infections. The mouse antisera could also effectively neutralize infection by pseudotyped SARS-CoV-2 with several natural mutations in RBD and the IgG extracted from the mouse antisera could also show neutralization against pseudotyped SARS-CoV and SARS-related coronavirus (SARSr-CoV). Vaccination of human ACE2 transgenic mice with RBD-Fc could effectively protect mice from the SARS-CoV-2 challenge. These results suggest that SARS-CoV-2 RBD-Fc has good potential to be further developed as an effective and broad-spectrum vaccine to prevent infection of the current SARS-CoV-2 and its mutants, as well as future emerging SARSr-CoVs and re-emerging SARS-CoV.

6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296092

ABSTRACT

The recurrent outbreak of coronaviruses and variants underscores the need for broadly reactive antivirals and vaccines. Here, a novel broad-spectrum human antibody named 76E1 was isolated from a COVID-19 convalescent patient and showed broad neutralization activity against multiple α- and β-coronaviruses, including the SARS-CoV-2 variants and also exhibited the binding breath to peptides containing the epitope from γ- and δ- coronaviruses. 76E1 cross-protects mice from SARS-CoV-2 and HCoV-OC43 infection in both prophylactic and treatment models. The epitope including the fusion peptide and S2’ cleavage site recognized by 76E1 was significantly conserved among α-, β-, γ- and δ- coronaviruses. We uncovered a novel mechanism of antibody neutralization that the epitope of 76E1 was proportionally less exposed in the prefusion trimeric structure of spike protein but could be unmasked by binding to the receptor ACE2. Once the epitope exposed, 76E1 inhibited S2’ cleavage, thus blocked the membrane fusion process. Our data demonstrate a key epitope targeted by broadly-neutralizing antibodies and will guide next-generation epitope-based pan-coronavirus vaccine design.

8.
Signal Transduct Target Ther ; 6(1): 378, 2021 11 03.
Article in English | MEDLINE | ID: covidwho-1500450

ABSTRACT

The current COVID-19 pandemic has heavily burdened the global public health system and may keep simmering for years. The frequent emergence of immune escape variants have spurred the search for prophylactic vaccines and therapeutic antibodies that confer broad protection against SARS-CoV-2 variants. Here we show that the bivalency of an affinity maturated fully human single-domain antibody (n3113.1-Fc) exhibits exquisite neutralizing potency against SARS-CoV-2 pseudovirus, and confers effective prophylactic and therapeutic protection against authentic SARS-CoV-2 in the host cell receptor angiotensin-converting enzyme 2 (ACE2) humanized mice. The crystal structure of n3113 in complex with the receptor-binding domain (RBD) of SARS-CoV-2, combined with the cryo-EM structures of n3113 and spike ecto-domain, reveals that n3113 binds to the side surface of up-state RBD with no competition with ACE2. The binding of n3113 to this novel epitope stabilizes spike in up-state conformations but inhibits SARS-CoV-2 S mediated membrane fusion, expanding our recognition of neutralization by antibodies against SARS-CoV-2. Binding assay and pseudovirus neutralization assay show no evasion of recently prevalent SARS-CoV-2 lineages, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) for n3113.1-Fc with Y58L mutation, demonstrating the potential of n3113.1-Fc (Y58L) as a promising candidate for clinical development to treat COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Neutralizing/chemistry , Antibodies, Viral/chemistry , COVID-19 , SARS-CoV-2/chemistry , Single-Chain Antibodies/chemistry , Angiotensin-Converting Enzyme 2/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , Crystallography, X-Ray , Epitopes/chemistry , Epitopes/immunology , Humans , Mice , SARS-CoV-2/immunology , Single-Chain Antibodies/immunology , Single-Chain Antibodies/therapeutic use
9.
Int J Mol Sci ; 22(21)2021 Nov 01.
Article in English | MEDLINE | ID: covidwho-1488619

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 infection poses a serious threat to global public health and the economy. The enzymatic product of cholesterol 25-hydroxylase (CH25H), 25-Hydroxycholesterol (25-HC), was reported to have potent anti-SARS-CoV-2 activity. Here, we found that the combination of 25-HC with EK1 peptide, a pan-coronavirus (CoV) fusion inhibitor, showed a synergistic antiviral activity. We then used the method of 25-HC modification to design and synthesize a series of 25-HC-modified peptides and found that a 25-HC-modified EK1 peptide (EK1P4HC) was highly effective against infections caused by SARS-CoV-2, its variants of concern (VOCs), and other human CoVs, such as HCoV-OC43 and HCoV-229E. EK1P4HC could protect newborn mice from lethal HCoV-OC43 infection, suggesting that conjugation of 25-HC with a peptide-based viral inhibitor was a feasible and universal strategy to improve its antiviral activity.


Subject(s)
Antiviral Agents/pharmacology , Hydroxycholesterols/chemistry , Lipopeptides/chemistry , SARS-CoV-2/drug effects , Amino Acid Sequence , Animals , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Body Weight/drug effects , COVID-19/drug therapy , COVID-19/virology , Coronavirus 229E, Human/drug effects , Coronavirus 229E, Human/pathogenicity , Coronavirus Infections/drug therapy , Coronavirus Infections/mortality , Coronavirus Infections/virology , Coronavirus OC43, Human/drug effects , Coronavirus OC43, Human/pathogenicity , Disease Models, Animal , Drug Synergism , Humans , Hydroxycholesterols/pharmacology , Hydroxycholesterols/therapeutic use , Lipopeptides/pharmacology , Lipopeptides/therapeutic use , Mice , Mice, Inbred BALB C , Polyethylene Glycols/chemistry , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Survival Rate , Virus Internalization/drug effects
10.
Cell Mol Immunol ; 17(8): 894, 2020 08.
Article in English | MEDLINE | ID: covidwho-1387295

ABSTRACT

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

13.
Acta Pharm Sin B ; 12(4): 1652-1661, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1336241

ABSTRACT

The development of broad-spectrum antivirals against human coronaviruses (HCoVs) is critical to combat the current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants, as well as future outbreaks of emerging CoVs. We have previously identified a polyethylene glycol-conjugated (PEGylated) lipopeptide, EK1C4, with potent pan-CoV fusion inhibitory activity. However, PEG linkers in peptide or protein drugs may reduce stability or induce anti-PEG antibodies in vivo. Therefore, we herein report the design and synthesis of a series of dePEGylated lipopeptide-based pan-CoV fusion inhibitors featuring the replacement of the PEG linker with amino acids in the heptad repeat 2 C-terminal fragment (HR2-CF) of HCoV-OC43. Among these lipopeptides, EKL1C showed the most potent inhibitory activity against infection by SARS-CoV-2 and its spike (S) mutants, as well as other HCoVs and some bat SARS-related coronaviruses (SARSr-CoVs) tested. The dePEGylated lipopeptide EKL1C exhibited significantly stronger resistance to proteolytic enzymes, better metabolic stability in mouse serum, higher thermostability than the PEGylated lipopeptide EK1C4, suggesting that EKL1C could be further developed as a candidate prophylactic and therapeutic for COVID-19 and other coronavirus diseases.

14.
Signal Transduct Target Ther ; 6(1): 288, 2021 07 29.
Article in English | MEDLINE | ID: covidwho-1333906

ABSTRACT

The COVID-19 pandemic poses a global threat to public health and economy. The continuously emerging SARS-CoV-2 variants present a major challenge to the development of antiviral agents and vaccines. In this study, we identified that EK1 and cholesterol-coupled derivative of EK1, EK1C4, as pan-CoV fusion inhibitors, exhibit potent antiviral activity against SARS-CoV-2 infection in both lung- and intestine-derived cell lines (Calu-3 and Caco2, respectively). They are also effective against infection of pseudotyped SARS-CoV-2 variants B.1.1.7 (Alpha) and B.1.1.248 (Gamma) as well as those with mutations in S protein, including N417T, E484K, N501Y, and D614G, which are common in South African and Brazilian variants. Crystal structure revealed that EK1 targets the HR1 domain in the SARS-CoV-2 S protein to block virus-cell fusion and provide mechanistic insights into its broad and effective antiviral activity. Nasal administration of EK1 peptides to hACE2 transgenic mice significantly reduced viral titers in lung and intestinal tissues. EK1 showed good safety profiles in various animal models, supporting further clinical development of EK1-based pan-CoV fusion inhibitors against SARS-CoV-2 and its variants.


Subject(s)
Antiviral Agents , COVID-19/drug therapy , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Virus Internalization/drug effects , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Caco-2 Cells , Crystallography, X-Ray , Drug Evaluation, Preclinical , Humans , Mice, Transgenic , Protein Domains , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
17.
Signal Transduct Target Ther ; 5(1): 282, 2020 11 27.
Article in English | MEDLINE | ID: covidwho-947524

ABSTRACT

The pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed serious threats to global health and economy, thus calling for the development of safe and effective vaccines. The receptor-binding domain (RBD) in the spike protein of SARS-CoV-2 is responsible for its binding to angiotensin-converting enzyme 2 (ACE2) receptor. It contains multiple dominant neutralizing epitopes and serves as an important antigen for the development of COVID-19 vaccines. Here, we showed that immunization of mice with a candidate subunit vaccine consisting of SARS-CoV-2 RBD and Fc fragment of human IgG, as an immunopotentiator, elicited high titer of RBD-specific antibodies with robust neutralizing activity against both pseudotyped and live SARS-CoV-2 infections. The mouse antisera could also effectively neutralize infection by pseudotyped SARS-CoV-2 with several natural mutations in RBD and the IgG extracted from the mouse antisera could also show neutralization against pseudotyped SARS-CoV and SARS-related coronavirus (SARSr-CoV). Vaccination of human ACE2 transgenic mice with RBD-Fc could effectively protect mice from the SARS-CoV-2 challenge. These results suggest that SARS-CoV-2 RBD-Fc has good potential to be further developed as an effective and broad-spectrum vaccine to prevent infection of the current SARS-CoV-2 and its mutants, as well as future emerging SARSr-CoVs and re-emerging SARS-CoV.


Subject(s)
Antibodies, Neutralizing/pharmacology , COVID-19 Vaccines/pharmacology , COVID-19/drug therapy , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/immunology , Epitopes/immunology , Humans , Immunoglobulin Fc Fragments/immunology , Immunoglobulin Fc Fragments/pharmacology , Mice , Mice, Inbred BALB C , Pandemics , Protein Binding/drug effects , Protein Binding/immunology , Receptors, Virus/genetics , Receptors, Virus/immunology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/antagonists & inhibitors
18.
Proc Natl Acad Sci U S A ; 117(44): 27141-27147, 2020 11 03.
Article in English | MEDLINE | ID: covidwho-834980

ABSTRACT

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has highlighted the urgent need to rapidly develop therapeutic strategies for such emerging viruses without effective vaccines or drugs. Here, we report a decoy nanoparticle against COVID-19 through a powerful two-step neutralization approach: virus neutralization in the first step followed by cytokine neutralization in the second step. The nanodecoy, made by fusing cellular membrane nanovesicles derived from human monocytes and genetically engineered cells stably expressing angiotensin converting enzyme II (ACE2) receptors, possesses an antigenic exterior the same as source cells. By competing with host cells for virus binding, these nanodecoys effectively protect host cells from the infection of pseudoviruses and authentic SARS-CoV-2. Moreover, relying on abundant cytokine receptors on the surface, the nanodecoys efficiently bind and neutralize inflammatory cytokines including interleukin 6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF), and significantly suppress immune disorder and lung injury in an acute pneumonia mouse model. Our work presents a simple, safe, and robust antiviral nanotechnology for ongoing COVID-19 and future potential epidemics.


Subject(s)
Coronavirus Infections/therapy , Cytokines/antagonists & inhibitors , Nanoparticles/therapeutic use , Pneumonia, Viral/therapy , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2 , Animals , Betacoronavirus , COVID-19 , Cell Membrane/chemistry , Granulocyte-Macrophage Colony-Stimulating Factor/antagonists & inhibitors , HEK293 Cells , Humans , Interleukin-6/antagonists & inhibitors , Mice , Mice, Inbred ICR , Monocytes , Nanoparticles/chemistry , Pandemics , Peptidyl-Dipeptidase A/metabolism , Receptors, Cytokine/metabolism , SARS-CoV-2 , THP-1 Cells
19.
JAMA Intern Med ; 180(10): 1356-1362, 2020 10 01.
Article in English | MEDLINE | ID: covidwho-718296

ABSTRACT

Importance: The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global public health. The association between clinical characteristics of the virus and neutralizing antibodies (NAbs) against this virus have not been well studied. Objective: To examine the association between clinical characteristics and levels of NAbs in patients who recovered from COVID-19. Design, Setting, and Participants: In this cohort study, a total of 175 patients with mild symptoms of COVID-19 who were hospitalized from January 24 to February 26, 2020, were followed up until March 16, 2020, at Shanghai Public Health Clinical Center, Shanghai, China. Exposures: SARS-CoV-2 infections were diagnosed and confirmed by reverse transcriptase-polymerase chain reaction testing of nasopharyngeal samples. Main Outcomes and Measures: The primary outcome was SARS-CoV-2-specific NAb titers. Secondary outcomes included spike-binding antibodies, cross-reactivity against SARS-associated CoV, kinetics of NAb development, and clinical information, including age, sex, disease duration, length of stay, lymphocyte counts, and blood C-reactive protein level. Results: Of the 175 patients with COVID-19, 93 were female (53%); the median age was 50 (interquartile range [IQR], 37-63) years. The median length of hospital stay was 16 (IQR, 13-21) days, and the median disease duration was 22 (IQR, 18-26) days. Variable levels of SARS-CoV-2-specific NAbs were observed at the time of discharge (50% inhibitory dose [ID50], 1076 [IQR, 448-2048]). There were 10 patients whose NAb titers were less than the detectable level of the assay (ID50, <40), and 2 patients who showed very high titers of NAbs, with ID50 levels of 15 989 and 21 567. NAbs were detected in patients from day 4 to 6 and reached peak levels from day 10 to 15 after disease onset. NAbs were unable to cross-react with SARS-associated CoV and NAb titers correlated with the spike-binding antibodies targeting S1 (r = 0.451; 95% CI, 0.320-0.564; P < .001), receptor binding domain (r = 0.484; 95% CI, 0.358-0.592; P < .001), and S2 regions (r = 0.346; 95% CI, 0.204-0.473; P < .001). NAb titers at the time of discharge were significantly higher in the 82 men (1417 [IQR, 541-2253]) than those in the 93 women (905 [IQR, 371-1687]) (median difference, 512; 95% CI, 82-688; P = .01) and at the time of follow-up in 56 male patients (1049 [IQR, 552-2454]) vs 61 female patients (751 [IQR, 216-1301]) (median difference, 298; 95% CI, 86-732; P = .009). Plasma NAb titers were significantly higher in 56 older (1537 [IQR, 877-2427) and 63 middle-aged (1291 [IQR, 504-2126]) patients than in 56 younger patients (459 [IQR, 225-998]) (older vs younger: median difference, 1078; 95% CI, 548-1287; P < .001; middle-aged vs younger: median difference, 832; 95% CI, 284-1013; P < .001). The NAb titers were correlated with plasma C-reactive protein levels (r = 0.508; 95% CI, 0.386-0.614; P < .001) and negatively correlated with lymphocyte counts (r = -0.427; 95% CI, -0.544 to -0.293; P < .001) at the time of admission. Conclusions and Relevance: In this cohort study, among 175 patients who recovered from mild COVID-19 in Shanghai, China, NAb titers to SARS-CoV-2 appeared to vary substantially. Further research is needed to understand the clinical implications of differing NAb titers for protection against future infection.


Subject(s)
Antibodies, Neutralizing/analysis , Betacoronavirus , Coronavirus Infections/blood , Coronavirus Infections/therapy , Pneumonia, Viral/blood , Pneumonia, Viral/therapy , Adult , COVID-19 , China , Cohort Studies , Coronavirus Infections/epidemiology , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/epidemiology , SARS-CoV-2
20.
Chinese J. Clin. Pharmacol. Ther. ; 3(25): 241-245, 20200326.
Article in Chinese | WHO COVID, ELSEVIER | ID: covidwho-682724

ABSTRACT

At the end of 2019,an outbreak of 2019 new coronavirus infectious disease (COVID-19) in Wuhan spread rapidly in China and reported cases in other countries.The number of infected cases and deaths quickly exceeded Severe Acute Respiratory Syndrome (SARS) in a short period of time,resulting in incalculable losses to China.Chinese researchers have quickly identified the pathogen,2019-nCoV (or SARS-CoV-2 or HCoV-19) and carried out the research and development of antiviral drugs at different levels.This article briefly reviews the current advancement of research and development of new therapeutics against 2019-nCoV infection.Given that the progress of research and development of antiviral drugs against the emerging and reemerging pathogens is relatively backwarded,we suggest that the research and development of antivirals against pathogens with pandemic or epidemic potential should be carried out in advance before the occurrence of the outbreaks. At the national level,we should promote the research and development of broad-spectrum antivirals and clinical trials to combat the pathogens with epidemic risk.

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