Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add filters

Language
Year range
1.
Cell Mol Immunol ; 19(5): 577-587, 2022 May.
Article in English | MEDLINE | ID: covidwho-1830043

ABSTRACT

Neutrophil extracellular traps (NETs) can capture and kill viruses, such as influenza viruses, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV), thus contributing to host defense. Contrary to our expectation, we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2, as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse model. The histone H3 or H4 selectively binds to subunit 2 of the spike (S) protein, as shown by a biochemical binding assay, surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino acids. Sialic acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S protein. Moreover, histones enhance cell-cell fusion. Finally, treatment with an inhibitor of NETosis, histone H3 or H4, or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse model. These findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Histones , Mice , N-Acetylneuraminic Acid , Protein Subunits/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Virus Internalization
2.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315882

ABSTRACT

Background: The outbreak and pandemic of coronavirus SARS CoV 2 caused significant threaten to global public health and economic consequences. It is extremely urgent that global people must take actions to develop safe and effective preventions and therapeutics. Nanobodies, which are derived from single‑chain camelid antibodies, had shown antiviral properties in various challenge viruses. In this study, multivalent nanobodies with high affinity blocking SARS CoV 2 spike interaction with ACE2 protein were developed. Results: Totally, four specific nanobodies against spike protein and its RBD domain were screened from a naïve VHH library. Among them, Nb91 hFc and Nb3 hFc demonstrated antiviral activity by neutralizing spike pseudotyped viruses in vitro. Subsequently, multivalent nanobodies were constructed to improve the neutralizing capacity. As a result, heterodimer nanobody Nb91 Nb3 hFc exhibited the strongest RBD binding affinity and neutralizing ability against SARS CoV 2 pseudoviruses with an IC50 value at approximately 1.54 nM. Conclusions: The present study indicated that naïve VHH library could be used as a potential resource for rapid acquisition and exploitation of antiviral nanobodies. Heterodimer nanobody Nb91 Nb3 hFc may serve as a potential therapeutic agent for the treatment of COVID 19.

3.
MedComm ; 2021.
Article in English | EuropePMC | ID: covidwho-1567268

ABSTRACT

SARS‐CoV‐2 is an enveloped positive‐sense RNA virus that depends on host factors for all stages of its life. Membrane receptor ACE2 is a well‐established factor for SARS‐CoV‐2 docking. In addition to ACE2, whole‐genome genetic screens have identified additional proteins, such as endosomal trafficking regulators SNX27 and retromer, as key host factors required for SARS‐CoV‐2 infection. However, it is poorly understood how SARS‐CoV‐2 utilize host endocytic transport pathways to produce productive infection. Here, we report that SNX27 interacts with the SARS‐CoV‐2 spike (S) protein to facilitate S protein surface expression. Interestingly, S protein binds to the PDZ domain of SNX27, although it does not contain a PDZ‐binding motif (PDZbm). Either abrogation of the SNX27 PDZ domain or S protein “MTSC” motif, which is critical for SNX27 binding, decreases surface expression of S protein and viral production. Collectively, our study highlights a novel approach utilized by SARS‐CoV‐2 to facilitate virion trafficking to establish virus infection. Proposed model showing SNX27 promotes intracellular trafficking of S protein and viral production. (a) SNX27, via its PDZ domain, interacts with S protein and promotes endosome‐to‐plasma membrane trafficking of S protein. SNX27 could also promote the production of SARS‐CoV‐2 virions in host cells, although the mechanism remains poorly defined. (b) Depletion of SNX27 impairs endosome‐to‐plasma membrane trafficking of S protein, leading to its lysosomal degradation.

4.
J Nanobiotechnology ; 19(1): 33, 2021 Jan 29.
Article in English | MEDLINE | ID: covidwho-1054825

ABSTRACT

BACKGROUND: The outbreak and pandemic of coronavirus SARS-CoV-2 caused significant threaten to global public health and economic consequences. It is extremely urgent that global people must take actions to develop safe and effective preventions and therapeutics. Nanobodies, which are derived from single­chain camelid antibodies, had shown antiviral properties in various challenge viruses. In this study, multivalent nanobodies with high affinity blocking SARS-CoV-2 spike interaction with ACE2 protein were developed. RESULTS: Totally, four specific nanobodies against spike protein and its RBD domain were screened from a naïve VHH library. Among them, Nb91-hFc and Nb3-hFc demonstrated antiviral activity by neutralizing spike pseudotyped viruses in vitro. Subsequently, multivalent nanobodies were constructed to improve the neutralizing capacity. As a result, heterodimer nanobody Nb91-Nb3-hFc exhibited the strongest RBD-binding affinity and neutralizing ability against SARS-CoV-2 pseudoviruses with an IC50 value at approximately 1.54 nM. CONCLUSIONS: The present study indicated that naïve VHH library could be used as a potential resource for rapid acquisition and exploitation of antiviral nanobodies. Heterodimer nanobody Nb91-Nb3-hFc may serve as a potential therapeutic agent for the treatment of COVID-19.


Subject(s)
Single-Domain Antibodies/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Binding Sites , HEK293 Cells , Humans , Neutralization Tests , Protein Binding , Protein Domains , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/antagonists & inhibitors
SELECTION OF CITATIONS
SEARCH DETAIL