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1.
Bioorg Med Chem ; 67: 116838, 2022 08 01.
Article in English | MEDLINE | ID: covidwho-1872946

ABSTRACT

Honokiol, isolated from a traditional Chinese medicine (TCM) Magnolia officinalis, is a biphenolic compound with several biological activities. To improve and broaden its biological activity, herein, two series of honokiol thioethers bearing 1,3,4-oxadiazole moieties were prepared and assessed for their α-glucosidase and SARS-CoV-2 entry inhibitory activities. Among all the honokiol thioethers, compound 7l exhibited the strongest α-glucosidase inhibitory effect with an IC50 value of 18.9 ± 2.3 µM, which was superior to the reference drug acarbose (IC50 = 24.4 ± 0.3 µM). Some interesting results of structure-activity relationships (SARs) have also been discussed. Enzyme kinetic study demonstrated that 7l was a noncompetitive α-glucosidase inhibitor, which was further supported by the results of molecular docking. Moreover, honokiol thioethers 7e, 9a, 9e, and 9r exhibited potent antiviral activity against SARS-CoV-2 pseudovirus entering into HEK-293 T-ACE2h. Especially 9a displayed the strongest inhibitory activity against SARS-CoV-2 pseudovirus entry with an IC50 value of 16.96 ± 2.45 µM, which was lower than the positive control Evans blue (21.98 ± 1.98 µM). Biolayer interferometry (BLI) binding and docking studies suggested that 9a and 9r may effectively block the binding of SARS-CoV-2 to the host ACE2 receptor through dual recognition of SARS-CoV-2 spike RBD and human ACE2. Additionally, the potent honokiol thioethers 7l, 9a, and 9r displayed relatively no cytotoxicity to normal cells (LO2). These findings will provide a theoretical basis for the discovery of honokiol derivatives as potential both α-glucosidase and SARS-CoV-2 entry inhibitors.


Subject(s)
COVID-19 , SARS-CoV-2 , Angiotensin-Converting Enzyme 2 , Biphenyl Compounds , COVID-19/drug therapy , HEK293 Cells , Humans , Lignans , Molecular Docking Simulation , Oxadiazoles , Protein Binding , Spike Glycoprotein, Coronavirus/chemistry , Sulfides , alpha-Glucosidases/metabolism
2.
Adv Exp Med Biol ; 1366: 137-153, 2022.
Article in English | MEDLINE | ID: covidwho-1782744

ABSTRACT

With the increasing global human population, travel, and socioeconomic activities, more and more novel pathogenic viruses will emerge or re-emerge. While more than 260 viruses are known to infect humans, only a small minority of these viral diseases are treatable by clinically approved antiviral drugs. Apart from these identified viruses, new emerging viruses and drug-resistant viruses are also important challenges to our public health and healthcare systems. The COVID-19 and influenza pandemics remind us the importance of getting broad-spectrum antivirals against emerging and re-emerging respiratory viruses. Broad-spectrum antivirals against different viral families for fighting the currently known viruses and novel emerging viruses are urgently needed. Viral entry is the universal first step for viral infection, and therefore is a promising target for identifying broad-spectrum antivirals. In this chapter, we mainly focus on discussing the risks of respiratory viruses, the challenge of finding broad-spectrum antivirals, the entry processes of respiratory viruses, the current studies on broad-spectrum entry inhibitors for respiratory viruses, and the directions for discovering broad-spectrum antivirals in the future.


Subject(s)
COVID-19 , Virus Diseases , Viruses , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Humans , Virus Diseases/drug therapy , Virus Internalization
3.
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
4.
Int J Mol Sci ; 23(7)2022 Apr 06.
Article in English | MEDLINE | ID: covidwho-1776252

ABSTRACT

Entry inhibitors against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed to control the outbreak of coronavirus disease 2019 (COVID-19). This study developed a robust and straightforward assay that detected the molecular interaction between the receptor-binding domain (RBD) of viral spike protein and the angiotensin-converting enzyme 2 (ACE2) receptor in just 10 min. A drug library of 1068 approved compounds was used to screen for SARS-CoV2 entry inhibition, and 9 active drugs were identified as specific pseudovirus entry inhibitors. A plaque reduction neutralization test using authentic SARS-CoV-2 virus in Vero E6 cells confirmed that 2 of these drugs (Etravirine and Dolutegravir) significantly inhibited the infection of SARS-CoV-2. With molecular docking, we showed that both Etravirine and Dolutegravir are preferentially bound to primary ACE2-interacting residues on the RBD domain, implying that these two drug blocks may prohibit the viral attachment of SARS-CoV-2. We compared the neutralizing activities of these entry inhibitors against different pseudoviruses carrying spike proteins from alpha, beta, gamma, and delta variants. Both Etravirine and Dolutegravir showed similar neutralizing activities against different variants, with EC50 values between 4.5 to 5.8 nM for Etravirine and 10.2 to 22.9 nM for Dolutegravir. These data implied that Etravirine and Dolutegravir may serve as general spike inhibitors against dominant viral variants of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Angiotensin-Converting Enzyme 2 , COVID-19/drug therapy , Humans , Molecular Docking Simulation , RNA, Viral , Spike Glycoprotein, Coronavirus/metabolism
5.
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
6.
Molecules ; 27(5)2022 Mar 07.
Article in English | MEDLINE | ID: covidwho-1732132

ABSTRACT

The COVID-19 pandemic has led to the search for new molecules with antiviral activity against SARS-CoV-2. The entry of the virus into the cell is one of the main targets for inhibiting SARS-CoV-2 infection. Natural products are an important source of new therapeutic alternatives against diseases. Pseudotyped viruses allow the study of SARS-CoV-2 viral entry inhibitors, and due to their simplicity, they allow the screening of a large number of antiviral candidates in Biosafety Level 2 facilities. We used pseudotyped HIV-1 with the D614G SARS-CoV-2 spike glycoprotein to test its ability to infect ACE2-expressing HEK 293T cells in the presence of diverse natural products, including 21 plant extracts, 7 essential oils, and 13 compounds from plants and fungi. The 50% cytotoxic concentration (CC50) was evaluated using the resazurin method. From these analyses, we determined the inhibitory activity of the extract of Stachytarpheta cayennensis, which had a half-maximal inhibitory concentration (IC50) of 91.65 µg/mL, a CC50 of 693.5 µg/mL, and a selectivity index (SI) of 7.57, indicating its potential use as an inhibitor of SARS-CoV-2 entry. Moreover, our work indicates the usefulness of the pseudotyped-virus system in the screening of SARS-CoV-2 entry inhibitors.


Subject(s)
Antiviral Agents/pharmacology , Biological Products/chemistry , Virus Internalization/drug effects , Actinobacteria/chemistry , Actinobacteria/metabolism , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Biological Products/metabolism , Biological Products/pharmacology , Biological Products/therapeutic use , COVID-19/drug therapy , COVID-19/virology , HEK293 Cells , High-Throughput Screening Assays/methods , Humans , Oils, Volatile/chemistry , Oils, Volatile/pharmacology , Oils, Volatile/therapeutic use , Plant Extracts/chemistry , Plant Extracts/metabolism , Plant Extracts/pharmacology , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/metabolism
7.
Viruses ; 14(2)2022 02 08.
Article in English | MEDLINE | ID: covidwho-1674832

ABSTRACT

An escalating pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has severely impacted global health. There is a severe lack of specific treatment options for diseases caused by SARS-CoV-2. In this study, we used a pseudotype virus (pv) containing the SARS-CoV-2 S glycoprotein to screen a botanical drug library containing 1037 botanical drugs to identify agents that prevent SARS-CoV-2 entry into the cell. Our study identified four hits, including angeloylgomisin O, schisandrin B, procyanidin, and oleanonic acid, as effective SARS-CoV-2 S pv entry inhibitors in the micromolar range. A mechanistic study revealed that these four agents inhibited SARS-CoV-2 S pv entry by blocking spike (S) protein-mediated membrane fusion. Furthermore, angeloylgomisin O and schisandrin B inhibited authentic SARS-CoV-2 with a high selective index (SI; 50% cytotoxic concentration/50% inhibition concentration). Our drug combination studies performed in cellular antiviral assays revealed that angeloylgomisin O has synergistic effects in combination with remdesivir, a drug widely used to treat SARS-CoV-2-mediated infections. We also showed that two hits could inhibit the newly emerged alpha (B.1.1.7) and beta (B.1.351) variants. Our findings collectively indicate that angeloylgomisin O and schisandrin B could inhibit SARS-CoV-2 efficiently, thereby making them potential therapeutic agents to treat the coronavirus disease of 2019.


Subject(s)
Antiviral Agents/pharmacology , Plant Extracts/pharmacology , SARS-CoV-2/drug effects , Small Molecule Libraries/pharmacology , Virus Internalization/drug effects , Animals , COVID-19/drug therapy , Caco-2 Cells , Cell Line , Chlorocebus aethiops , Cricetinae , Drug Discovery , HEK293 Cells , Humans , Vero Cells
8.
Antiviral Res ; 196: 105197, 2021 12.
Article in English | MEDLINE | ID: covidwho-1509565

ABSTRACT

SARS-CoV-2 enters host cells after binding through its spike glycoprotein to the angiotensin-converting enzyme 2 (ACE2) receptor. Soluble ACE2 ectodomains bind and neutralize the virus, yet their short in vivo half-live limits their therapeutic use. This limitation can be overcome by fusing the fragment crystallizable (Fc) part of human immunoglobulin G (IgG) to the ACE2 ectodomain, but this bears the risk of Fc-receptor activation and antibody-dependent cellular cytotoxicity. Here, we describe optimized ACE2-IgG4-Fc fusion constructs that avoid Fc-receptor activation, preserve the desired ACE2 enzymatic activity and show promising pharmaceutical properties. The engineered ACE2-IgG4-Fc fusion proteins neutralize the original SARS-CoV, pandemic SARS-CoV-2 as well as the rapidly spreading SARS-CoV-2 alpha, beta and delta variants of concern. Importantly, these variants of concern are inhibited at picomolar concentrations proving that ACE2-IgG4 maintains - in contrast to therapeutic antibodies - its full antiviral potential. Thus, ACE2-IgG4-Fc fusion proteins are promising candidate anti-antivirals to combat the current and future pandemics.


Subject(s)
Angiotensin-Converting Enzyme 2 , Antiviral Agents/chemical synthesis , COVID-19/drug therapy , Immunoglobulin G , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/therapeutic use , Antiviral Agents/therapeutic use , Humans , Protein Binding , SARS-CoV-2/drug effects
9.
J Med Virol ; 93(10): 5825-5832, 2021 10.
Article in English | MEDLINE | ID: covidwho-1432413

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has focused attention on the need to develop effective therapeutics against the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and also against other pathogenic coronaviruses. In this study, we report on a kind of bisbenzylisoquinoline alkaloid, neferine, as a pan-coronavirus entry inhibitor. Neferine effectively protected HEK293/hACE2 and HuH7 cell lines from infection by different coronaviruses pseudovirus particles (SARS-CoV-2, SARS-CoV-2 [D614G, N501Y/D614G, 501Y.V1, 501Y.V2, 501Y.V3 variants], SARS-CoV, MERS-CoV) in vitro, with median effect concentration (EC50 ) of 0.13-0.41 µM. Neferine blocked host calcium channels, thus inhibiting Ca2+ -dependent membrane fusion and suppressing virus entry. This study provides experimental data to support the fact that neferine may be a promising lead for pan-coronaviruses therapeutic drug development.


Subject(s)
Antiviral Agents/pharmacology , Benzylisoquinolines/pharmacology , Calcium/metabolism , SARS-CoV-2/drug effects , Virus Internalization/drug effects , COVID-19/virology , Cell Line , Coronavirus/drug effects , Coronavirus/physiology , HEK293 Cells , Humans , Isoquinolines/pharmacology , Phenols/pharmacology , SARS-CoV-2/physiology
10.
J Virol ; 94(23)2020 11 09.
Article in English | MEDLINE | ID: covidwho-774840

ABSTRACT

Numerous peptides inhibit the entry of enveloped viruses into cells. Some of these peptides have been shown to inhibit multiple unrelated viruses. We have suggested that such broad-spectrum antiviral peptides share a property called interfacial activity; they are somewhat hydrophobic and amphipathic, with a propensity to interact with the interfacial zones of lipid bilayer membranes. In this study, we further tested the hypothesis that such interfacial activity is a correlate of broad-spectrum antiviral activity. In this study, several families of peptides, selected for the ability to partition into and disrupt membrane integrity but with no known antiviral activity, were tested for the ability to inhibit multiple diverse enveloped viruses. These include Lassa pseudovirus, influenza virus, dengue virus type 2, herpes simplex virus 1, and nonenveloped human adenovirus 5. Various families of interfacially active peptides caused potent inhibition of all enveloped viruses tested at low and submicromolar concentrations, well below the range in which they are toxic to mammalian cells. These membrane-active peptides block uptake and fusion with the host cell by rapidly and directly interacting with virions, destabilizing the viral envelope, and driving virus aggregation and/or intervirion envelope fusion. We speculate that the molecular characteristics shared by these peptides can be exploited to enable the design, optimization, or molecular evolution of novel broad-spectrum antiviral therapeutics.IMPORTANCE New classes of antiviral drugs are needed to treat the ever-changing viral disease landscape. Current antiviral drugs treat only a small number of viral diseases, leaving many patients with established or emerging infections to be treated solely with supportive care. Recent antiviral peptide research has produced numerous membrane-interacting peptides that inhibit diverse enveloped viruses in vitro and in vivo Peptide therapeutics are becoming more common, with over 60 FDA-approved peptides for clinical use. Included in this class of therapeutics is enfuvirtide, a 36-residue peptide drug that inhibits HIV entry/fusion. Due to their broad-spectrum mechanism of action and enormous potential sequence diversity, peptides that inhibit virus entry could potentially fulfill the need for new antiviral therapeutics; however, a better understanding of their mechanism is needed for the optimization or evolution of sequence design to combat the wide landscape of viral disease.


Subject(s)
Antiviral Agents/pharmacology , Peptides/chemistry , Peptides/metabolism , Virus Internalization/drug effects , Viruses/drug effects , Animals , Chlorocebus aethiops , Dogs , HEK293 Cells , Humans , Madin Darby Canine Kidney Cells , Orthomyxoviridae , Vero Cells , Viral Envelope , Virus Diseases/drug therapy
11.
Am J Respir Cell Mol Biol ; 65(1): 41-53, 2021 07.
Article in English | MEDLINE | ID: covidwho-1158161

ABSTRACT

Coronavirus disease (COVID-19) is an acute infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human SP-D (surfactant protein D) is known to interact with the spike protein of SARS-CoV, but its immune surveillance against SARS-CoV-2 is not known. The current study aimed to examine the potential of a recombinant fragment of human SP-D (rfhSP-D) as an inhibitor of replication and infection of SARS-CoV-2. The interaction of rfhSP-D with the spike protein of SARS-CoV-2 and human ACE-2 (angiotensin-converting enzyme 2) receptor was predicted via docking analysis. The inhibition of interaction between the spike protein and ACE-2 by rfhSP-D was confirmed using direct and indirect ELISA. The effect of rfhSP-D on replication and infectivity of SARS-CoV-2 from clinical samples was assessed by measuring the expression of RdRp gene of the virus using quantitative PCR. In silico interaction studies indicated that three amino acid residues in the receptor-binding domain of spike protein of SARS-CoV-2 were commonly involved in interacting with rfhSP-D and ACE-2. Studies using clinical samples of SARS-CoV-2-positive cases (asymptomatic, n = 7; symptomatic, n = 8) and negative control samples (n = 15) demonstrated that treatment with 1.67 µM rfhSP-D inhibited viral replication by ∼5.5-fold and was more efficient than remdesivir (100 µM) in Vero cells. An approximately two-fold reduction in viral infectivity was also observed after treatment with 1.67 µM rfhSP-D. These results conclusively demonstrate that the rfhSP-D mediated calcium independent interaction between the receptor-binding domain of the S1 subunit of the SARS-CoV-2 spike protein and human ACE-2, its host cell receptor, and significantly reduced SARS-CoV-2 infection and replication in vitro.


Subject(s)
COVID-19/metabolism , Pulmonary Surfactant-Associated Protein D , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus , Virus Replication , Adult , Animals , Chlorocebus aethiops , Female , Humans , Male , Protein Binding , Pulmonary Surfactant-Associated Protein D/chemistry , Pulmonary Surfactant-Associated Protein D/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells
12.
Small Methods ; 5(2): 2001031, 2021 Feb 15.
Article in English | MEDLINE | ID: covidwho-986422

ABSTRACT

The ongoing corona virus disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2 infection, has resulted in hundreds of thousands of deaths. Cellular entry of SARS-CoV-2, which is mediated by the viral spike protein and ACE2 receptor, is an essential target for the development of vaccines, therapeutic antibodies, and drugs. Using a mammalian cell expression system, a genetically engineered sensor of fluorescent protein (Gamillus)-fused SARS-CoV-2 spike trimer (STG) to probe the viral entry process is developed. In ACE2-expressing cells, it is found that the STG probe has excellent performance in the live-cell visualization of receptor binding, cellular uptake, and intracellular trafficking of SARS-CoV-2 under virus-free conditions. The new system allows quantitative analyses of the inhibition potentials and detailed influence of COVID-19-convalescent human plasmas, neutralizing antibodies and compounds, providing a versatile tool for high-throughput screening and phenotypic characterization of SARS-CoV-2 entry inhibitors. This approach may also be adapted to develop a viral entry visualization system for other viruses.

13.
Cell Rep ; 33(12): 108528, 2020 12 22.
Article in English | MEDLINE | ID: covidwho-978234

ABSTRACT

Soluble forms of angiotensin-converting enzyme 2 (ACE2) have recently been shown to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We report on an improved soluble ACE2, termed a "microbody," in which the ACE2 ectodomain is fused to Fc domain 3 of the immunoglobulin (Ig) heavy chain. The protein is smaller than previously described ACE2-Ig Fc fusion proteins and contains an H345A mutation in the ACE2 catalytic active site that inactivates the enzyme without reducing its affinity for the SARS-CoV-2 spike. The disulfide-bonded ACE2 microbody protein inhibits entry of SARS-CoV-2 spike protein pseudotyped virus and replication of live SARS-CoV-2 in vitro and in a mouse model. Its potency is 10-fold higher than soluble ACE2, and it can act after virus bound to the cell. The microbody inhibits the entry of ß coronaviruses and virus with the variant D614G spike. The ACE2 microbody may be a valuable therapeutic for coronavirus disease 2019 (COVID-19) that is active against viral variants and future coronaviruses.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/pharmacology , Immunoglobulin Fc Fragments/metabolism , Microbodies/metabolism , SARS-CoV-2/drug effects , Amino Acid Sequence , Animals , COVID-19/prevention & control , COVID-19/virology , Disease Models, Animal , Disulfides/metabolism , Female , HEK293 Cells , Humans , Male , Mice, Transgenic , Protein Domains , Protein Multimerization , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Virion/metabolism , Virus Internalization/drug effects
14.
Phytomedicine ; 85: 153396, 2021 May.
Article in English | MEDLINE | ID: covidwho-929314

ABSTRACT

BACKGROUND: Currently, novel coronavirus disease (Covid-19) outbreak creates global panic across the continents, as people from almost all countries and territories have been affected by this highly contagious viral disease. The scenario is deteriorating due to lack of proper & specific target-oriented pharmacologically safe prophylactic agents or drugs, and or any effective vaccine. drug development is urgently required to back in the normalcy in the community and to combat this pandemic. PURPOSE: Thus, we have proposed two novel drug targets, Furin and TMPRSS2, as Covid-19 treatment strategy. We have highlighted this target-oriented novel drug delivery strategy, based on their pathophysiological implication on SARS-CoV-2 infection, as evident from earlier SARS-CoV-1, MERS, and influenza virus infection via host cell entry, priming, fusion, and endocytosis. STUDY DESIGN &  METHODS: An earlier study suggested that Furin and TMPRSS2 knockout mice had reduced level of viral load and a lower degree of organ damage such as the lung. The present study thus highlights the promise of some selected novel and potential anti-viral Phytopharmaceutical that bind to Furin and TMPRSS2 as target. RESULT: Few of them had shown promising anti-viral response in both preclinical and clinical study with acceptable therapeutic safety-index. CONCLUSION: Hence, this strategy may limit life-threatening Covid-19 infection and its mortality rate through nano-suspension based intra-nasal or oral nebulizer spray, to treat mild to moderate SARS-COV-2 infection when Furin and TMPRSS2 receptor may initiate to express and activate for processing the virus to cause cellular infection by replication within the host cell and blocking of host-viral interaction.


Subject(s)
COVID-19/drug therapy , Furin/antagonists & inhibitors , Phytochemicals/pharmacology , Receptors, Virus/antagonists & inhibitors , Serine Endopeptidases/metabolism , Serine Proteinase Inhibitors/pharmacology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Animals , Furin/metabolism , Humans , Mice , Mice, Knockout , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism
15.
J Membr Biol ; 253(5): 425-444, 2020 10.
Article in English | MEDLINE | ID: covidwho-734824

ABSTRACT

The emerging and re-emerging viral infections are constant threats to human health and wellbeing. Several strategies have been explored to develop vaccines against these viral diseases. The main effort in the journey of development of vaccines is to neutralize the fusion protein using antibodies. However, significant efforts have been made in discovering peptides and small molecules that inhibit the fusion between virus and host cell, thereby inhibiting the entry of viruses. This class of inhibitors is called entry inhibitors, and they are extremely efficient in reducing viral infection as the entry of the virus is considered as the first step of infection. Nevertheless, these inhibitors are highly selective for a particular virus as antibody-based vaccines. The recent COVID-19 pandemic lets us ponder to shift our attention towards broad-spectrum antiviral agents from the so-called 'one bug-one drug' approach. This review discusses peptide and small molecule-based entry inhibitors against class I, II, and III viruses and sheds light on broad-spectrum antiviral agents.


Subject(s)
Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Membrane Fusion/drug effects , Pneumonia, Viral/drug therapy , Virus Internalization/drug effects , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Humans , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , SARS-CoV-2
16.
J Virol ; 94(22)2020 10 27.
Article in English | MEDLINE | ID: covidwho-730921

ABSTRACT

The ongoing coronavirus disease 2019 (COVID-19) pandemic has caused >20 million infections and >750,000 deaths. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, has been found closely related to the bat coronavirus strain RaTG13 (Bat-CoV RaTG13) and a recently identified pangolin coronavirus (Pangolin-CoV-2020). Here, we first investigated the ability of SARS-CoV-2 and three related coronaviruses to utilize animal orthologs of angiotensin-converting enzyme 2 (ACE2) for cell entry. We found that ACE2 orthologs of a wide range of domestic and wild mammals, including camels, cattle, horses, goats, sheep, cats, rabbits, and pangolins, were able to support cell entry of SARS-CoV-2, suggesting that these species might be able to harbor and spread this virus. In addition, the pangolin and bat coronaviruses, Pangolin-CoV-2020 and Bat-CoV RaTG13, were also found able to utilize human ACE2 and a number of animal-ACE2 orthologs for cell entry, indicating risks of spillover of these viruses into humans in the future. We then developed potently anticoronavirus ACE2-Ig proteins that are broadly effective against the four distinct coronaviruses. In particular, through truncating ACE2 at its residue 740 but not 615, introducing a D30E mutation, and adopting an antibody-like tetrameric-ACE2 configuration, we generated an ACE2-Ig variant that neutralizes SARS-CoV-2 at picomolar range. These data demonstrate that the improved ACE2-Ig variants developed in this study could potentially be developed to protect from SARS-CoV-2 and some other SARS-like viruses that might spillover into humans in the future.IMPORTANCE The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of the currently uncontrolled coronavirus disease 2019 (COVID-19) pandemic. It is important to study the host range of SARS-CoV-2, because some domestic species might harbor the virus and transmit it back to humans. In addition, insight into the ability of SARS-CoV-2 and SARS-like viruses to utilize animal orthologs of the SARS-CoV-2 receptor ACE2 might provide structural insight into improving ACE2-based viral entry inhibitors. In this study, we found that ACE2 orthologs of a wide range of domestic and wild animals can support cell entry of SARS-CoV-2 and three related coronaviruses, providing insights into identifying animal hosts of these viruses. We also developed recombinant ACE2-Ig proteins that are able to potently block these viral infections, providing a promising approach to developing antiviral proteins broadly effective against these distinct coronaviruses.


Subject(s)
Antibodies, Neutralizing/genetics , Betacoronavirus/physiology , Coronavirus/classification , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Neutralizing/chemistry , Betacoronavirus/genetics , Coronavirus/genetics , Coronavirus/physiology , Disease Models, Animal , HEK293 Cells , Humans , Immunoglobulins/chemistry , Immunoglobulins/genetics , Models, Chemical , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Receptors, Virus/chemistry , Receptors, Virus/genetics , Recombinant Proteins/genetics , SARS-CoV-2 , Virus Internalization/drug effects
17.
J Mol Graph Model ; 100: 107697, 2020 11.
Article in English | MEDLINE | ID: covidwho-665694

ABSTRACT

Angiotensin-converting enzyme 2 (ACE2) is a membrane-bound zinc metallopeptidase that generates the vasodilatory peptide angiotensin 1-7 and thus performs a protective role in heart disease. It is considered an important therapeutic target in controlling the COVID-19 outbreak, since SARS-CoV-2 enters permissive cells via an ACE2-mediated mechanism. The present in silico study attempted to repurpose existing drugs for use as prospective viral-entry inhibitors targeting human ACE2. Initially, a clinically approved drug library of 7,173 ligands was screened against the receptor using molecular docking, followed by energy minimization and rescoring of docked ligands. Finally, potential binders were inspected to ensure molecules with different scaffolds were engaged in favorable contacts with both the metal cofactor and the critical residues lining the receptor's active site. The results of the calculations suggest that lividomycin, burixafor, quisinostat, fluprofylline, pemetrexed, spirofylline, edotecarin, and diniprofylline emerge as promising repositionable drug candidates for stabilizing the closed (substrate/inhibitor-bound) conformation of ACE2, thereby shifting the relative positions of the receptor's critical exterior residues recognized by SARS-CoV-2. This study is among the rare ones in the relevant scientific literature to search for potential ACE2 inhibitors. In practical terms, the drugs, unmodified as they are, may be introduced into the therapeutic armamentarium of the ongoing fight against COVID-19 now, or their scaffolds may serve as rich skeletons for designing novel ACE2 inhibitors in the near future.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/chemistry , Antiviral Agents/chemistry , Betacoronavirus/chemistry , Peptidyl-Dipeptidase A/chemistry , Small Molecule Libraries/chemistry , Amino Acid Motifs , Angiotensin-Converting Enzyme 2 , Betacoronavirus/enzymology , COVID-19 , Carbazoles/chemistry , Catalytic Domain , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Drug Repositioning , Dyphylline/analogs & derivatives , Dyphylline/chemistry , Host-Pathogen Interactions , Humans , Hydroxamic Acids/chemistry , Ligands , Molecular Docking Simulation , Pandemics , Paromomycin/analogs & derivatives , Paromomycin/chemistry , Pemetrexed/chemistry , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Protein Binding , Protein Interaction Domains and Motifs , Protein Structure, Secondary , SARS-CoV-2 , Structure-Activity Relationship , Thermodynamics
18.
Int J Mol Sci ; 21(11)2020 May 28.
Article in English | MEDLINE | ID: covidwho-401521

ABSTRACT

In the past 17 years, three novel coronaviruses have caused severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the coronavirus disease 2019 (COVID-19). As emerging infectious diseases, they were characterized by their novel pathogens and transmissibility without available clinical drugs or vaccines. This is especially true for the newly identified COVID-19 caused by SARS coronavirus 2 (SARS-CoV-2) for which, to date, no specific antiviral drugs or vaccines have been approved. Similar to SARS and MERS, the lag time in the development of therapeutics is likely to take months to years. These facts call for the development of broad-spectrum anti-coronavirus drugs targeting a conserved target site. This review will systematically describe potential broad-spectrum coronavirus fusion inhibitors, including antibodies, protease inhibitors, and peptide fusion inhibitors, along with a discussion of their advantages and disadvantages.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Protease Inhibitors/therapeutic use , Viral Fusion Protein Inhibitors/therapeutic use , Animals , Betacoronavirus/physiology , Humans , Protease Inhibitors/adverse effects , Protease Inhibitors/pharmacology , SARS-CoV-2 , Viral Fusion Protein Inhibitors/adverse effects , Viral Fusion Protein Inhibitors/pharmacology , Virus Internalization/drug effects
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