scholarly journals Pharmacophore-based peptide biologics neutralize SARS-CoV-2 S1 and deter S1-ACE2 interaction in vitro

2020 ◽  
Author(s):  
Masaud Shah ◽  
Sung Ung Moon ◽  
Hyun Goo Woo
Keyword(s):  
Cell Attachment ◽  
Immune Surveillance ◽  
Cell Entry ◽  
Viral Fusion ◽  
Receptor Binding Domain ◽  
Spontaneous Movement ◽  
Viral Receptor ◽  
Dose Dependent ◽  
Host Immune Surveillance

AbstractEffective therapeutics and stable vaccine are the urgent need of the day to combat COVID-19 pandemic. SARS-CoV-2 spike protein has a pivotal role in cell-entry and host immune response, thus regarded as potential drug- and vaccine-target. As the virus utilizes the S1 domain of spike to initiate cell-attachment and S2 domain for membrane fusion, several attempts have been made to design viral-receptor and viral-fusion blockers. Here, by deploying interactive structure-based design and pharmacophore-based approaches, we designed short and stable peptide-biologics i.e. CoV-spike-neutralizing peptides (CSNPs) including CSNP1, CSNP2, CSNP3, CSNP4. We could demonstrate in cell culture experiments that CSNP2 binds to S1 at submicromolar concentration and abrogates the S1-hACE2 interaction. CSNP3, a modified and downsized form of CSNP2, could neither interfere with the S1-hACE2 interaction nor bind to S1. CSNP4 exhibited dose-dependent binding to both S1 and hACE2 and abolished the S1-hACE2 interaction in vitro. CSNP4 possibly enhance the mAb-based S1 neutralization by limiting the spontaneous movement of spike receptor-binding domain (RBD), whereas CSNP2 allowed RBD-mAb binding without any steric hindrance. Taken together, we suggest that CSNP2 and CSNP4 are potent and stable candidate peptides that can neutralize the SARS-CoV-2 spike and possibly pose the virus to host immune surveillance.

scholarly journals A structure-based rationale for sialic acid independent host-cell entry of Sosuga virus

2019 ◽  
Vol 116 (43) ◽  
pp. 21514-21520 ◽  
Author(s):  
Alice J. Stelfox ◽  
Thomas A. Bowden
Keyword(s):  
Sialic Acid ◽  
Host Cell ◽  
Receptor Binding ◽  
Cell Attachment ◽  
Cell Entry ◽  
Head Region ◽  
Close Proximity ◽  
Host Cell Attachment ◽  
Host Cell Entry

The bat-borne paramyxovirus, Sosuga virus (SosV), is one of many paramyxoviruses recently identified and classified within the newly established genus Pararubulavirus, family Paramyxoviridae. The envelope surface of SosV presents a receptor-binding protein (RBP), SosV-RBP, which facilitates host-cell attachment and entry. Unlike closely related hemagglutinin neuraminidase RBPs from other genera of the Paramyxoviridae, SosV-RBP and other pararubulavirus RBPs lack many of the stringently conserved residues required for sialic acid recognition and hydrolysis. We determined the crystal structure of the globular head region of SosV-RBP, revealing that while the glycoprotein presents a classical paramyxoviral six-bladed β-propeller fold and structurally classifies in close proximity to paramyxoviral RBPs with hemagglutinin-neuraminidase (HN) functionality, it presents a receptor-binding face incongruent with sialic acid recognition. Hemadsorption and neuraminidase activity analysis confirms the limited capacity of SosV-RBP to interact with sialic acid in vitro and indicates that SosV-RBP undergoes a nonclassical route of host-cell entry. The close overall structural conservation of SosV-RBP with other classical HN RBPs supports a model by which pararubulaviruses only recently diverged from sialic acid binding functionality.

scholarly journals Iota-carrageenan neutralizes SARS-CoV-2 and inhibits viral replication in vitro

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0237480
Author(s):  
Martina Morokutti-Kurz ◽  
Maria Fröba ◽  
Philipp Graf ◽  
Maximilian Große ◽  
Andreas Grassauer ◽  
...  
Keyword(s):  
Clinical Effectiveness ◽  
Cell Entry ◽  
Dependent Manner ◽  
Duration Of Symptoms ◽  
Significant Public Health ◽  
Similar Range ◽  
Dose Dependent ◽  
Vitro Data ◽  
In Vitro Data

In the absence of a vaccine and other effective prophylactic or therapeutic countermeasures the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) remains a significant public health threat. Attachment and entry of coronaviruses including SARS-CoV-2 is mainly mediated by the spike glycoprotein. Here, we show that iota-carrageenan can inhibit the cell entry of the SARS-CoV-2 spike pseudotyped lentivirus in a dose dependent manner. SARS-CoV-2 spike pseudotyped lentivirus particles were efficiently neutralized with an IC50 value of 2.6 μg/ml iota-carrageenan. Experiments with patient isolated wild type SARS-CoV-2 virus showed an inhibition of replication in a similar range. In vitro data on iota-carrageenan against various Rhino- and endemic Coronaviruses showed similar IC50 values and translated readily into clinical effectiveness when a nasal spray containing iota-carrageenan demonstrated a reduction of severity and duration of symptoms of common cold caused by various respiratory viruses. Accordingly, our in vitro data on SARS-CoV-2 spike pseudotyped lentivirus and replication competent SARS-CoV-2 suggest that administration of iota-carrageenan may be an effective and safe prophylaxis or treatment for SARS-CoV-2 infections.

scholarly journals Protoporphyrin IX and verteporfin prevent SARS-CoV-2 infection in vitro and in a mouse model expressing human ACE2

2020 ◽  
Author(s):  
Chenjian Gu ◽  
Yang Wu ◽  
Huimin Guo ◽  
Yuanfei Zhu ◽  
Wei Xu ◽  
...  
Keyword(s):  
Cytopathic Effect ◽  
Antiviral Agents ◽  
Protoporphyrin Ix ◽  
Ring Structure ◽  
Receptor Binding Domain ◽  
Viral Receptor ◽  
Margin Of Safety ◽  
Approved Drugs ◽  
Fda Approved Drugs

AbstractThe SARS-CoV-2 infection is spreading rapidly worldwide. Efficacious antiviral therapeutics against SARS-CoV-2 is urgently needed. Here, we discovered that protoporphyrin IX (PpIX) and verteporfin, two FDA-approved drugs, completely inhibited the cytopathic effect produced by SARS-CoV-2 infection at 1.25 μM and 0.31 μM respectively, and their EC50 values of reduction of viral RNA were at nanomolar concentrations. The selectivity indices of PpIX and verteporfin were 952.74 and 368.93, respectively, suggesting broad margin of safety. Importantly, PpIX and verteporfin prevented SARS-CoV-2 infection in mice adenovirally transduced with human ACE2. The compounds, sharing a porphyrin ring structure, were shown to bind viral receptor ACE2 and interfere with the interaction between ACE2 and the receptor-binding domain of viral S protein. Our study suggests that PpIX and verteporfin are potent antiviral agents against SARS-CoV-2 infection and sheds new light on developing novel chemoprophylaxis and chemotherapy against SARS-CoV-2.

scholarly journals Development of a COVID-19 vaccine based on the receptor binding domain displayed on virus-like particles

2020 ◽  
Author(s):  
Lisha Zha ◽  
Hongxin Zhao ◽  
Mona O. Mohsen ◽  
Liang Hong ◽  
Yuhang Zhou ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Vaccine Candidate ◽  
Rapid Development ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Viral Receptor ◽  
Virus Like Particles ◽  
The City

AbstractThe recently ermerging disease COVID-19 is caused by the new SARS-CoV-2 virus first detected in the city of Wuhan, China. From there it has been rapidly spreading inside and outside China. With initial death rates around 4%, COVID-19 patients at longer distances from Wuhan showed reduced mortality as was previously observed for the SARS coronavirus. However, the new coronavirus spreads more strongly, as it sheds long before onset of symptoms or may be transmitted by people without symptoms. Rapid development of a protective vaccine against COVID-19 is therefore of paramount importance. Here we demonstrate that recombinantly expressed receptor binding domain (RBD) of the spike protein homologous to SARS binds to ACE2, the viral receptor. Higly repetitive display of RBD on immunologically optimized virus-like particles derived from cucumber mosaic virus resulted in a vaccine candidate (RBD-CuMVTT) that induced high levels of specific antibodies in mice which were able to block binding of spike protein to ACE2 and potently neutralized the SARS-CoV-2 virus in vitro.

scholarly journals Cell entry mechanisms of SARS-CoV-2

2020 ◽  
Vol 117 (21) ◽  
pp. 11727-11734 ◽  
Author(s):  
Jian Shang ◽  
Yushun Wan ◽  
Chuming Luo ◽  
Gang Ye ◽  
Qibin Geng ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Receptor Binding ◽  
Immune Surveillance ◽  
Intervention Strategies ◽  
Cell Entry ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Wide Spread ◽  
Virus Surface ◽  
Protease Activation

A novel severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2) is causing the global coronavirus disease 2019 (COVID-19) pandemic. Understanding how SARS-CoV-2 enters human cells is a high priority for deciphering its mystery and curbing its spread. A virus surface spike protein mediates SARS-CoV-2 entry into cells. To fulfill its function, SARS-CoV-2 spike binds to its receptor human ACE2 (hACE2) through its receptor-binding domain (RBD) and is proteolytically activated by human proteases. Here we investigated receptor binding and protease activation of SARS-CoV-2 spike using biochemical and pseudovirus entry assays. Our findings have identified key cell entry mechanisms of SARS-CoV-2. First, SARS-CoV-2 RBD has higher hACE2 binding affinity than SARS-CoV RBD, supporting efficient cell entry. Second, paradoxically, the hACE2 binding affinity of the entire SARS-CoV-2 spike is comparable to or lower than that of SARS-CoV spike, suggesting that SARS-CoV-2 RBD, albeit more potent, is less exposed than SARS-CoV RBD. Third, unlike SARS-CoV, cell entry of SARS-CoV-2 is preactivated by proprotein convertase furin, reducing its dependence on target cell proteases for entry. The high hACE2 binding affinity of the RBD, furin preactivation of the spike, and hidden RBD in the spike potentially allow SARS-CoV-2 to maintain efficient cell entry while evading immune surveillance. These features may contribute to the wide spread of the virus. Successful intervention strategies must target both the potency of SARS-CoV-2 and its evasiveness.

scholarly journals The interferon-stimulated exosomal hACE2 potently inhibits SARS-CoV-2 replication through competitively blocking the virus entry

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Junsong Zhang ◽  
Feng Huang ◽  
Baijin Xia ◽  
Yaochang Yuan ◽  
Fei Yu ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Virus Entry ◽  
Cell Types ◽  
Cell Entry ◽  
Converting Enzyme ◽  
Viral Receptor ◽  
Angiotensin Converting Enzyme 2 ◽  
Global Pandemic ◽  
Different Cell Types

AbstractSince the outbreak of coronavirus disease 2019 (COVID-19), it has become a global pandemic. The spike (S) protein of etiologic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specifically recognizes human angiotensin-converting enzyme 2 (hACE2) as its receptor, which is recently identified as an interferon (IFN)-stimulated gene. Here, we find that hACE2 exists on the surface of exosomes released by different cell types, and the expression of exosomal hACE2 is increased by IFNα/β treatment. In particular, exosomal hACE2 can specifically block the cell entry of SARS-CoV-2, subsequently inhibit the replication of SARS-CoV-2 in vitro and ex vivo. Our findings have indicated that IFN is able to upregulate a viral receptor on the exosomes which competitively block the virus entry, exhibiting a potential antiviral strategy.

scholarly journals Hantavirus Gc glycoprotein: evidence for a class II fusion protein

2005 ◽  
Vol 86 (11) ◽  
pp. 2937-2947 ◽  
Author(s):  
Nicole D. Tischler ◽  
Angel Gonzalez ◽  
Tomas Perez-Acle ◽  
Mario Rosemblatt ◽  
Pablo D. T. Valenzuela
Keyword(s):  
Fusion Protein ◽  
Cell Attachment ◽  
Molecular Model ◽  
Three Dimensional ◽  
Class Ii ◽  
Binding Activity ◽  
Viral Fusion ◽  
Fusion Peptides ◽  
Viral Fusion Protein

Hantavirus cell entry is promoted by its envelope glycoproteins, Gn and Gc, through cell attachment and by fusion between viral and endosomal membranes at low pH. However, the role of Gn and Gc in receptor binding and cell fusion has not yet been defined. In this work, a sequence presenting characteristics similar to those of class II fusion peptides (FPs) of alphavirus E1 and flavivirus E proteins is identified within the hantavirus Gc glycoprotein. A three-dimensional comparative molecular model based on crystallographic data of tick-borne encephalitis virus E protein is proposed for the Andes virus (ANDV) Gc ectodomain, which supports a feasible class II fusion-protein fold. In vitro experimental evidence is provided for the binding activity of the ANDV FP candidate to artificial membranes, as demonstrated by fluorescence anisotropy assays. Taken together, these results support the hypothesis that the Gc glycoprotein of hantaviruses and of other members of the family Bunyaviridae directs the viral fusion activity and that it may be classified as a class II viral fusion protein.

scholarly journals A Role for B Cells to Transmit Hepatitis C Virus Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Isabelle Desombere ◽  
Freya Van Houtte ◽  
Ali Farhoudi ◽  
Lieven Verhoye ◽  
Caroline Buysschaert ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
B Cells ◽  
Immune Surveillance ◽  
Serum Samples ◽  
Infected Blood ◽  
Cell Culture Systems ◽  
Hcv Transmission ◽  
Host Immune Surveillance

Hepatitis C virus (HCV) is highly variable and transmits through infected blood to establish a chronic liver infection in the majority of patients. Our knowledge on the infectivity of clinical HCV strains is hampered by the lack of in vitro cell culture systems that support efficient viral replication. We and others have reported that HCV can associate with and infect immune cells and may thereby evade host immune surveillance and elimination. To evaluate whether B cells play a role in HCV transmission, we assessed the ability of B cells and sera from recent (<2 years) or chronic (≥ 2 years) HCV patients to infect humanized liver chimeric mice. HCV was transmitted by B cells from chronic infected patients whereas the sera were non-infectious. In contrast, B cells from recently infected patients failed to transmit HCV to the mice, whereas all serum samples were infectious. We observed an association between circulating anti-glycoprotein E1E2 antibodies and B cell HCV transmission. Taken together, our studies provide evidence for HCV transmission by B cells, findings that have clinical implications for prophylactic and therapeutic antibody-based vaccine design.

scholarly journals The evolutionary history of ACE2 usage within the coronavirus subgenus Sarbecovirus

2020 ◽  
Author(s):  
H.L Wells ◽  
M Letko ◽  
G Lasso ◽  
B Ssebide ◽  
J Nziza ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Cell Entry ◽  
Receptor Binding Domain ◽  
Evolutionary Mechanisms ◽  
Host Tropism ◽  
The Past ◽  
Competitive Release ◽  
History Of ◽  
Alternative Scenarios

AbstractSARS-CoV-1 and SARS-CoV-2 are not phylogenetically closely related; however, both use the ACE2 receptor in humans for cell entry. This is not a universal sarbecovirus trait; for example, many known sarbecoviruses related to SARS-CoV-1 have two deletions in the receptor binding domain of the spike protein that render them incapable of using human ACE2. Here, we report three novel sarbecoviruses from Rwanda and Uganda which are phylogenetically intermediate to SARS-CoV-1 and SARS-CoV-2 and demonstrate via in vitro studies that they are also unable to utilize human ACE2. Furthermore, we show that the observed pattern of ACE2 usage among sarbecoviruses is most likely due to recombination. We show that the lineage that includes SARS-CoV-2 is most likely the ancestral ACE2-using lineage, and that recombination with at least one virus from this group conferred ACE2 usage to the progenitor of SARS-CoV-1 at some time in the past. We argue that alternative scenarios such as convergent evolution are much less parsimonious; we show that biogeography and patterns of host tropism support the plausibility of a recombination scenario; and we propose a competitive release hypothesis to explain how this recombination event could have occurred and why it is evolutionarily advantageous. The findings provide important insights into the natural history of ACE2 usage for both SARS-CoV-1 and SARS-CoV-2, and a greater understanding of the evolutionary mechanisms that shape zoonotic potential of coronaviruses. This study also underscores the need for increased surveillance for sarbecoviruses in southwestern China, where most ACE2-using viruses have been found to date, as well as other regions including Africa, where these viruses have only recently been discovered.

scholarly journals Potent neutralization of 2019 novel coronavirus by recombinant ACE2-Ig

2020 ◽  
Author(s):  
Changhai Lei ◽  
Wenyan Fu ◽  
Kewen Qian ◽  
Tian Li ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
Fusion Proteins ◽  
Antiviral Treatment ◽  
Cross Reactivity ◽  
Cell Entry ◽  
Receptor Binding Domain ◽  
Potential Applications ◽  
Novel Coronavirus ◽  
Entry Receptor ◽  
Potent Neutralization

Abstract2019-nCoV, which is a novel coronavirus emerged in Wuhan, China, at the end of 2019, has caused at least infected 11,844 as of Feb 1, 2020. However, there is no specific antiviral treatment or vaccine currently. Very recently report had suggested that novel CoV would use the same cell entry receptor, ACE2, as the SARS-CoV. In this report, we generated a novel recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. An ACE2 mutant with low catalytic activity was also used in the study. The fusion proteins were then characterized. Both fusion proteins has high affinity binding to the receptor-binding domain (RBD) of SARS-CoV and 2019-nCoV and exerted desired pharmacological properties. Moreover, fusion proteins potently neutralized SARS-CoV and 2019-nCoV in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they could have potential applications for diagnosis, prophylaxis, and treatment of 2019-nCoV.

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