scholarly journals An ultrapotent synthetic nanobody neutralizes SARS-CoV-2 by stabilizing inactive Spike

Science ◽  
2020 ◽  
pp. eabe3255 ◽  
Author(s):  
Michael Schoof ◽  
Bryan Faust ◽  
Reuben A. Saunders ◽  
Smriti Sangwan ◽  
Veronica Rezelj ◽  
...  
Keyword(s):  
Cell Receptor ◽  
Affinity Maturation ◽  
Host Cells ◽  
Spike Protein ◽  
Airway Epithelia ◽  
Angiotensin Converting Enzyme 2 ◽  
Inactive Conformation ◽  
Binding Domains ◽  
Host Cell Receptor ◽  
Yeast Surface

The SARS-CoV-2 virus enters host cells via an interaction between its Spike protein and the host cell receptor angiotensin converting enzyme 2 (ACE2). By screening a yeast surface-displayed library of synthetic nanobody sequences, we developed nanobodies that disrupt the interaction between Spike and ACE2. Cryogenic electron microscopy (cryo-EM) revealed that one nanobody, Nb6, binds Spike in a fully inactive conformation with its receptor binding domains (RBDs) locked into their inaccessible down-state, incapable of binding ACE2. Affinity maturation and structure-guided design of multivalency yielded a trivalent nanobody, mNb6-tri, with femtomolar affinity for Spike and picomolar neutralization of SARS-CoV-2 infection. mNb6-tri retains function after aerosolization, lyophilization, and heat treatment, which enables aerosol-mediated delivery of this potent neutralizer directly to the airway epithelia.

scholarly journals An ultra-potent synthetic nanobody neutralizes SARS-CoV-2 by locking Spike into an inactive conformation

2020 ◽  
Author(s):  
Michael Schoof ◽  
Bryan Faust ◽  
Reuben A. Saunders ◽  
Smriti Sangwan ◽  
Veronica Rezelj ◽  
...  
Keyword(s):  
Viral Entry ◽  
Cell Receptor ◽  
Affinity Maturation ◽  
Host Cells ◽  
Angiotensin Converting Enzyme 2 ◽  
Inactive Conformation ◽  
Binding Domains ◽  
Host Cell Receptor ◽  
Yeast Surface ◽  
And Function

ABSTRACTWithout an effective prophylactic solution, infections from SARS-CoV-2 continue to rise worldwide with devastating health and economic costs. SARS-CoV-2 gains entry into host cells via an interaction between its Spike protein and the host cell receptor angiotensin converting enzyme 2 (ACE2). Disruption of this interaction confers potent neutralization of viral entry, providing an avenue for vaccine design and for therapeutic antibodies. Here, we develop single-domain antibodies (nanobodies) that potently disrupt the interaction between the SARS-CoV-2 Spike and ACE2. By screening a yeast surface-displayed library of synthetic nanobody sequences, we identified a panel of nanobodies that bind to multiple epitopes on Spike and block ACE2 interaction via two distinct mechanisms. Cryogenic electron microscopy (cryo-EM) revealed that one exceptionally stable nanobody, Nb6, binds Spike in a fully inactive conformation with its receptor binding domains (RBDs) locked into their inaccessible down-state, incapable of binding ACE2. Affinity maturation and structure-guided design of multivalency yielded a trivalent nanobody, mNb6-tri, with femtomolar affinity for SARS-CoV-2 Spike and picomolar neutralization of SARS-CoV-2 infection. mNb6-tri retains stability and function after aerosolization, lyophilization, and heat treatment. These properties may enable aerosol-mediated delivery of this potent neutralizer directly to the airway epithelia, promising to yield a widely deployable, patient-friendly prophylactic and/or early infection therapeutic agent to stem the worst pandemic in a century.

scholarly journals CD147-spike protein is a novel route for SARS-CoV-2 infection to host cells

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ke Wang ◽  
Wei Chen ◽  
Zheng Zhang ◽  
Yongqiang Deng ◽  
Jian-Qi Lian ◽  
...  
Keyword(s):  
Virus Entry ◽  
Rapid Evolution ◽  
Cell Receptor ◽  
Host Cells ◽  
Spike Protein ◽  
Dependent Manner ◽  
Viral Loads ◽  
Host Cell Receptor ◽  
Human T Cells ◽  
Effective Drugs

AbstractIn face of the everlasting battle toward COVID-19 and the rapid evolution of SARS-CoV-2, no specific and effective drugs for treating this disease have been reported until today. Angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV-2, mediates the virus infection by binding to spike protein. Although ACE2 is expressed in the lung, kidney, and intestine, its expressing levels are rather low, especially in the lung. Considering the great infectivity of COVID-19, we speculate that SARS-CoV-2 may depend on other routes to facilitate its infection. Here, we first discover an interaction between host cell receptor CD147 and SARS-CoV-2 spike protein. The loss of CD147 or blocking CD147 in Vero E6 and BEAS-2B cell lines by anti-CD147 antibody, Meplazumab, inhibits SARS-CoV-2 amplification. Expression of human CD147 allows virus entry into non-susceptible BHK-21 cells, which can be neutralized by CD147 extracellular fragment. Viral loads are detectable in the lungs of human CD147 (hCD147) mice infected with SARS-CoV-2, but not in those of virus-infected wild type mice. Interestingly, virions are observed in lymphocytes of lung tissue from a COVID-19 patient. Human T cells with a property of ACE2 natural deficiency can be infected with SARS-CoV-2 pseudovirus in a dose-dependent manner, which is specifically inhibited by Meplazumab. Furthermore, CD147 mediates virus entering host cells by endocytosis. Together, our study reveals a novel virus entry route, CD147-spike protein, which provides an important target for developing specific and effective drug against COVID-19.

scholarly journals Increasing Host Cellular Receptor—Angiotensin-Converting Enzyme 2 (ACE2) Expression by Coronavirus may Facilitate 2019-nCoV Infection

2020 ◽  
Author(s):  
Pei-Hui Wang ◽  
Yun Cheng
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Emerging Infectious Diseases ◽  
Cell Receptor ◽  
Host Cells ◽  
Cellular Receptor ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Host Cell Receptor ◽  
Coronavirus Infection ◽  
Entry Receptor

AbstractThe ongoing outbreak of a new coronavirus (2019-nCoV) causes an epidemic of acute respiratory syndrome in humans. 2019-nCoV rapidly spread to national regions and multiple other countries, thus, pose a serious threat to public health. Recent studies show that spike (S) proteins of 2019-nCoV and SARS-CoV may use the same host cell receptor called angiotensin-converting enzyme 2 (ACE2) for entering into host cells. The affinity between ACE2 and 2019-nCoV S is much higher than ACE2 binding to SARS-CoV S protein, explaining that why 2019-nCoV seems to be more readily transmitted from the human to human. Here, we reported that ACE2 can be significantly upregulated after infection of various viruses including SARS-CoV and MERS-CoV. Basing on findings here, we propose that coronavirus infection can positively induce its cellular entry receptor to accelerate their replication and spread, thus drugs targeting ACE2 expression may be prepared for the future emerging infectious diseases caused by this cluster of viruses.

scholarly journals Lions, tigers and kittens too: ACE2 and susceptibility to COVID-19

2020 ◽  
Vol 2020 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Sabateeshan Mathavarajah ◽  
Graham Dellaire
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Cell Receptor ◽  
Spike Protein ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Host Cell Receptor ◽  
Specific Manner ◽  
Species Specific ◽  
Computational Analyses

Abstract SARS-CoV-2 (Severe Acute Respiratory Syndrome coronavirus 2) has been reported to infect domesticated animals in a species-specific manner, where cats were susceptible but not dogs. Using the recently published crystal structure of the SARS-CoV-2 spike protein complexed with the human host cell receptor angiotensin converting enzyme 2 (ACE2), we characterized the structure and evolution of ACE2 in several of these species and identify a single interacting amino acid residue conserved between human and Felidae ACE2 but not in Canidae that correlates with virus susceptibility. Using computational analyses we describe how this site likely affects ACE2 targeting by the virus. Thus, we highlight how evolution-based approaches can be used to form hypotheses and study animal transmission of such viruses in the future.

scholarly journals Mutations in two SARS-CoV-2 variants of concern reflect two distinct strategies of antibody escape

2021 ◽  
Author(s):  
Sebastian Fiedler ◽  
Viola Denninger ◽  
Alexey S. Morgunov ◽  
Alison Ilsley ◽  
Roland Worth ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Cell Receptor ◽  
Converting Enzyme ◽  
Wild Type ◽  
Angiotensin Converting Enzyme 2 ◽  
Binding Domains ◽  
Host Cell Receptor

Understanding the factors that contribute to antibody escape of SARS-CoV-2 and its variants is key for the development of drugs and vaccines that provide broad protection against a variety of virus variants. Using microfluidic diffusional sizing, we determined the dissociation constant ((KD)) for the interaction between receptor binding domains (RBDs) of SARS-CoV-2 in its original version (WT) as well as alpha and beta variants with the host-cell receptor angiotensin converting enzyme 2 (ACE2). For RBD-alpha, the ACE2-binding affinity was increased by a factor of ten when compared with RBD-WT, while ACE2-binding of RBD-beta was largely unaffected. However, when challenged with a neutralizing antibody that binds to both RBD-WT and RBD-alpha with low nanomolar (KD) values, RBD-beta displayed no binding, suggesting a substantial epitope change. In SARS-CoV-2 convalescent sera, RBD-binding antibodies showed low nanomolar affinities to both wild-type and variant RBD proteins—strikingly, the concentration of antibodies binding to RBD-beta was half that of RBD-WT and RBD-alpha, again indicating considerable epitope changes in the beta variant. Our data therefore suggests that one factor contributing to the higher transmissibility and antibody evasion of SARS-CoV-2 alpha and beta is a larger fraction of viruses that can form a complex with ACE2. However, the two variants employ different mechanisms to achieve this goal. While SARS-CoV-2 alpha RBD binds with greater affinity to ACE2 and is thus more difficult to displace from the receptor by neutralizing antibodies, RBD-beta is less accessible to antibodies due to epitope changes which increases the chances of ACE2-binding and infection.

Understanding the Role of Corona Virus based on Current Scientific Evidence - A Review with Emerging Importance in Pandemic

2020 ◽  
Vol 15 (2) ◽  
pp. 89-103
Author(s):  
Suman K. Ray ◽  
Sukhes Mukherjee
Keyword(s):  
Host Cell ◽  
Scientific Evidence ◽  
Antibody Therapy ◽  
Cell Receptor ◽  
Spike Protein ◽  
Virus Infectivity ◽  
Angiotensin Converting Enzyme 2 ◽  
Host Cell Receptor ◽  
Antiviral Medications

: Coronavirus disease is a potentially deadly disease and of significant apprehension for global communal health because of its lethality. Vaccines and antiviral medications are still under trial to prevent or treat human coronavirus (HCoV) till date. The virus HCoV originated in 2003, SARS-CoV, which causes respiratory syndrome having distinctive pathogenesis and infections of the respiratory tract. A mechanism was projected for the evolution of SARS virus, and a handy association with bats was found. When this virus reaches the respective host system, the infection starts with spike protein binding to its complementary receptor of the host cell. The coronavirus spike protein’s association with its host cell receptor complement is crucial in deciding the virus infectivity, tissue tropism and species variety. Recent studies show that SARS Coronavirus 2 or COVID-19 requires protease to get into cells, offering a new therapeutic target. Distinctive attention and exertions should be given to defending or reducing transmission in vulnerable populaces, including those directly associated with caregiving and treatment and also aged one. Researchers are planning to develop a vaccine for COVID-19, and in this approach are also considered developing a vaccine that sensitizes our immune system preventing from this pandemic. The present review focuses on the role of S-spike protein in COVID-19, which helps the virus intruding the enzyme ACE2 (Angiotensin-Converting Enzyme 2). Passive antibody therapy is an additional alternative to use blood donors from hale and hearty people who have already recovered from COVID-19 and therapeutic advancement in handling the COVID-19 pandemic.

scholarly journals The N-terminal domain of spike glycoprotein mediates SARS-CoV-2 infection by associating with L-SIGN and DC-SIGN

2020 ◽  
Author(s):  
Wai Tuck Soh ◽  
Yafei Liu ◽  
Emi E. Nakayama ◽  
Chikako Ono ◽  
Shiho Torii ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Cell Receptor ◽  
Spike Protein ◽  
Primary Host ◽  
Angiotensin Converting Enzyme 2 ◽  
Lectin Receptor ◽  
Terminal Domain ◽  
Host Cell Receptor ◽  
Protein Serum

The widespread occurrence of SARS-CoV-2 has had a profound effect on society and a vaccine is currently being developed. Angiotensin-converting enzyme 2 (ACE2) is the primary host cell receptor that interacts with the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. Although pneumonia is the main symptom in severe cases of SARS-CoV-2 infection, the expression levels of ACE2 in the lung is low, suggesting the presence of another receptor for the spike protein. In order to identify the additional receptors for the spike protein, we screened a receptor for the SARS-CoV-2 spike protein from the lung cDNA library. We cloned L-SIGN as a specific receptor for the N-terminal domain (NTD) of the SARS-CoV-2 spike protein. The RBD of the spike protein did not bind to L-SIGN. In addition, not only L-SIGN but also DC-SIGN, a closely related C-type lectin receptor to L-SIGN, bound to the NTD of the SARS-CoV-2 spike protein. Importantly, cells expressing L-SIGN and DC-SIGN were both infected by SARS-CoV-2. Furthermore, L-SIGN and DC-SIGN induced membrane fusion by associating with the SARS-CoV-2 spike protein. Serum antibodies from infected patients and a patient-derived monoclonal antibody against NTD inhibited SARS-CoV-2 infection of L-SIGN or DC-SIGN expressing cells. Our results highlight the important role of NTD in SARS-CoV-2 dissemination through L-SIGN and DC-SIGN and the significance of having anti-NTD neutralizing antibodies in antibody-based therapeutics.

scholarly journals The Importance of Therapeutically Targeting the Binary Toxin from Clostridioides difficile

2021 ◽  
Vol 22 (6) ◽  
pp. 2926
Author(s):  
Dinendra L. Abeyawardhane ◽  
Raquel Godoy-Ruiz ◽  
Kaylin A. Adipietro ◽  
Kristen M. Varney ◽  
Richard R. Rustandi ◽  
...  
Keyword(s):  
Host Cell ◽  
The Elderly ◽  
Cell Receptor ◽  
Host Cells ◽  
Binary Toxin ◽  
Clostridioides Difficile ◽  
Host Cell Receptor ◽  
Oligomeric Assembly ◽  
Nosocomial Disease ◽  
Binary Toxins

Novel therapeutics are needed to treat pathologies associated with the Clostridioides difficile binary toxin (CDT), particularly when C. difficile infection (CDI) occurs in the elderly or in hospitalized patients having illnesses, in addition to CDI, such as cancer. While therapies are available to block toxicities associated with the large clostridial toxins (TcdA and TcdB) in this nosocomial disease, nothing is available yet to treat toxicities arising from strains of CDI having the binary toxin. Like other binary toxins, the active CDTa catalytic subunit of CDT is delivered into host cells together with an oligomeric assembly of CDTb subunits via host cell receptor-mediated endocytosis. Once CDT arrives in the host cell’s cytoplasm, CDTa catalyzes the ADP-ribosylation of G-actin leading to degradation of the cytoskeleton and rapid cell death. Although a detailed molecular mechanism for CDT entry and host cell toxicity is not yet fully established, structural and functional resemblances to other binary toxins are described. Additionally, unique conformational assemblies of individual CDT components are highlighted herein to refine our mechanistic understanding of this deadly toxin as is needed to develop effective new therapeutic strategies for treating some of the most hypervirulent and lethal strains of CDT-containing strains of CDI.

scholarly journals Virtual screening as therapeutic strategy of COVID-19 targeting angiotensin-converting enzyme 2

2021 ◽  
Vol 2 (1) ◽  
pp. 16-27
Author(s):  
Zahra Sharifinia ◽  
◽  
Samira Asadi ◽  
Mahyar Irani ◽  
Abdollah Allahverdi ◽  
...  
Keyword(s):  
Virtual Screening ◽  
Angiotensin Converting Enzyme ◽  
Host Cells ◽  
Spike Protein ◽  
Potential Drug ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Approved Drugs ◽  
Fda Approved Drugs

Objective: The receptor-binding domain (RBD) of the S1 domain of the SARS-CoV- 2 Spike protein performs a key role in the interaction with Angiotensin-converting enzyme 2 (ACE2), leading to both subsequent S2 domain-mediated membrane fusion and incorporation of viral RNA in host cells. Methods: In this study, we investigated the inhibitor’s targeted compounds through existing human ACE2 drugs to use as a future viral invasion. 54 FDA approved drugs were selected to assess their binding affinity to the ACE2 receptor. The structurebased methods via computational ones have been used for virtual screening of the best drugs from the drug database. Key Findings: The ligands “Cinacalcet” and “Levomefolic acid” highaffinity scores can be a potential drug preventing Spike protein of SARS-CoV-2 and human ACE2 interaction. Levomefolic acid from vitamin B family was proved to be a potential drug as a spike protein inhibitor in previous clinical and computational studies. Besides that, in this study, the capability of Levomefolic acid to avoid ACE2 and Spike protein of SARS-CoV-2 interaction is indicated. Therefore, it is worth to consider this drug for more in vitro investigations as ACE2 and Spike protein inhibition candidate. Conclusion: The two Cinacalcet and Levomefolic acid are the two ligands that have highest energy binding for human ACE2 blocking among 54 FDA approved drugs.

Adherence of Legionella pneumophila to U-937 cells, guinea-pig alveolar macrophages, and MRC-5 cells by a novel, complement-independent binding mechanism

1994 ◽  
Vol 40 (10) ◽  
pp. 865-872 ◽  
Author(s):  
Frank C. Gibson III ◽  
Arthur O. Tzianabos ◽  
Frank G. Rodgers
Keyword(s):  
Monoclonal Antibodies ◽  
Guinea Pig ◽  
Host Cell ◽  
Alveolar Macrophages ◽  
Legionella Pneumophila ◽  
Cell Receptor ◽  
Host Cells ◽  
Order Kinetic ◽  
Complement Receptors ◽  
Host Cell Receptor

In the absence of serum, Legionella pneumophila demonstrated wash-resistant adherence to U-937 cells, primary guinea-pig alveolar macrophages, and MRC-5 cells. Neither complement nor antibody was required for binding. The dynamics of adherence following inoculation of L. pneumophila at increasing 10-fold multiplicities of infection to each of the three host cell types resulted in a first-order kinetic relationship of binding, indicative of one bacterial adhesin molecule recognized by one host cell receptor moiety. Host cell receptor saturation studies showed that depending on the cell type, 2–8% of the bacterial inoculum adhered to cells under these nonopsonic conditions. Preliminary adhesin and receptor characterization studies were preformed to define the chemical composition of the binding structures on both the organism and the three different host cell surfaces. The adherence phenomenon was investigated using competitive binding assays in the presence of putative adhesin analogs as well as following treatments modifying the microbial and host cell surface membranes. Attachment was evaluated both by viable bacterial cell colony counts and by indirect immunofluorescent assay. With the exception of aldehyde treatments, the various membrane-modifying regimes and the presence of the adhesin analogs were shown to have no effect on organism or host cell viability. Data suggested that the L. pneumophila adhesin responsible for opsonin-independent binding to these host cells was a protein structure with lectin-like properties. Furthermore, this protein would appear to be intimately associated with carbohydrate or lipid structures located on the bacterial outer membrane. The receptor moiety present on all host cells responsible for binding L. pneumophila had properties consistent with a carbohydrate or complex saccharide structure. To evaluate the role of complement receptors as the structures necessary for L. pneumophila infection of macrophages, a battery of monoclonal antibodies were used to block the complement receptor (CR) types 1 (CD35), CR3 (CD 18, CD11b), and CR4 (CD18, CD11c). Blocking studies with CR-specific monoclonal antibodies indicated that CR1 and the integrin receptors CR3 and CR4 were not involved in the opsonin-independent binding of L. pneumophila to macrophage-like cells.Key words: Legionella, opsonin-independent attachment, bacterial adherence, complement receptors, adhesion–receptor interactions.

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