scholarly journals Integrin activation is an essential component of SARS-CoV-2 infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter Simons ◽  
Derek A. Rinaldi ◽  
Virginie Bondu ◽  
Alison M. Kell ◽  
Steven Bradfute ◽  
...  
Keyword(s):  
Peptide Inhibitors ◽  
Cell Entry ◽  
Productive Infection ◽  
Integrin Activation ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Binding Function ◽  
Cell Permeable Peptide ◽  
Integrin Antagonists

AbstractSARS-CoV-2 infection depends on binding its spike (S) protein to angiotensin-converting enzyme 2 (ACE2). The S protein expresses an RGD motif, suggesting that integrins may be co-receptors. Here, we UV-inactivated SARS-CoV-2 and fluorescently labeled the envelope membrane with octadecyl rhodamine B (R18) to explore the role of integrin activation in mediating cell entry and productive infection. We used flow cytometry and confocal microscopy to show that SARS-CoV-2R18 particles engage basal-state integrins. Furthermore, we demonstrate that Mn2+, which induces integrin extension, enhances cell entry of SARS-CoV-2R18. We also show that one class of integrin antagonist, which binds to the αI MIDAS site and stabilizes the inactive, closed conformation, selectively inhibits the engagement of SARS-CoV-2R18 with basal state integrins, but is ineffective against Mn2+-activated integrins. RGD-integrin antagonists inhibited SARS-CoV-2R18 binding regardless of integrin activation status. Integrins transmit signals bidirectionally: 'inside-out' signaling primes the ligand-binding function of integrins via a talin-dependent mechanism, and 'outside-in' signaling occurs downstream of integrin binding to macromolecular ligands. Outside-in signaling is mediated by Gα13. Using cell-permeable peptide inhibitors of talin and Gα13 binding to the cytoplasmic tail of an integrin's β subunit, we demonstrate that talin-mediated signaling is essential for productive infection.

scholarly journals Integrin activation is an essential component of SARS-CoV-2 infection

2021 ◽  
Author(s):  
Peter Simons ◽  
Derek Rinaldi ◽  
Virginie Bondu ◽  
Alison Kell ◽  
Steven Bradfute ◽  
...  
Keyword(s):  
Cell Entry ◽  
Productive Infection ◽  
Integrin Activation ◽  
Angiotensin Converting Enzyme 2 ◽  
Binding Function ◽  
Cell Permeable Peptide ◽  
Level 3 ◽  
Integrin Antagonists ◽  
Activity State

Cellular entry of coronaviruses depends on binding of the viral spike (S) protein to a specific cellular receptor, the angiotensin-converting enzyme 2 (ACE2). Furthermore, the viral spike protein expresses an RGD motif, suggesting that cell surface integrins may be attachment co-receptors. However, using infectious SARS-CoV-2 requires a biosafety level 3 laboratory (BSL-3), which limits the techniques that can be used to study the mechanism of cell entry. Here, we UV-inactivated SARS-CoV-2 and fluorescently labeled the envelope membrane with octadecyl rhodamine B (R18) to explore the role of integrin activation in mediating both cell entry and productive infection. We used flow cytometry and confocal fluorescence microscopy to show that fluorescently labeled SARS-CoV-2R18 particles engage basal-state integrins. Furthermore, we demonstrate that Mn2+, which activates integrins and induces integrin extension, enhances cell binding and entry of SARS-CoV-2R18 in proportion to the fraction of integrins activated. We also show that one class of integrin antagonist, which binds to the αI MIDAS site and stabilizes the inactive, closed conformation, selectively inhibits the engagement of SARS-CoV-2R18 with basal state integrins, but is ineffective against Mn2+-activated integrins. At the same time, RGD-integrin antagonists inhibited SARS-CoV-2R18 binding regardless of integrin activity state. Integrins transmit signals bidirectionally: 'inside-out' signaling primes the ligand binding function of integrins via a talin dependent mechanism and 'outside-in' signaling occurs downstream of integrin binding to macromolecular ligands. Outside-in signaling is mediated by Gα13 and induces cell spreading, retraction, migration, and proliferation. Using cell-permeable peptide inhibitors of talin, and Gα13 binding to the cytoplasmic tail of an integrin's β subunit, we further demonstrate that talin-mediated signaling is essential for productive infection by SARS-CoV-2.

scholarly journals Investigation of the genetic variation in ACE2 on the structural recognition by the novel coronavirus (SARS-CoV-2)

2020 ◽  
Author(s):  
Xingyi Guo ◽  
Zhishan Chen ◽  
Yumin Xia ◽  
Weiqiang Lin ◽  
Hongzhi Li
Keyword(s):  
Genetic Variation ◽  
The Novel ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Missense Variants ◽  
Catalytic Metal ◽  
Using Data ◽  
Novel Coronavirus ◽  
Insight Into

Abstract Background: The outbreak of coronavirus disease (COVID-19) was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), through its surface spike glycoprotein (S-protein) recognition on the receptor Angiotensin-converting enzyme 2 (ACE2) in humans. However, it remains unclear how genetic variations in ACE2 may affect its function and structure, and consequently alter the recognition by SARS-CoV-2. Methods: We have systemically characterized missense variants in the gene ACE2 using data from the Genome Aggregation Database (gnomAD; N = 141,456). To investigate the putative deleterious role of missense variants, six existing functional prediction tools were applied to evaluate their impact. We further analyzed the structural flexibility of ACE2 and its protein-protein interface with the S-protein of SARS-CoV-2 using our developed Legion Interfaces Analysis (LiAn) program.Results: Here, we characterized a total of 12 ACE2 putative deleterious missense variants. Of those 12 variants, we further showed that p.His378Arg could directly weaken the binding of catalytic metal atom to decrease ACE2 activity and p.Ser19Pro could distort the most important helix to the S-protein. Another seven missense variants may affect secondary structures (i.e. p.Gly211Arg; p.Asp206Gly; p.Arg219Cys; p.Arg219His, p.Lys341Arg, p.Ile468Val, and p.Ser547Cys), whereas p.Ile468Val with AF = 0.01 is only present in Asian.Conclusions: We provide strong evidence of putative deleterious missense variants in ACE2 that are present in specific populations, which could disrupt the function and structure of ACE2. These findings provide novel insight into the genetic variation in ACE2 which may affect the SARS-CoV-2 recognition and infection, and COVID-19 susceptibility and treatment.

scholarly journals Angiotensin-Converting Enzyme 2 (ACE2) in the Pathogenesis of ARDS in COVID-19

2021 ◽  
Vol 12 ◽  
Author(s):  
Keiji Kuba ◽  
Tomokazu Yamaguchi ◽  
Josef M. Penninger
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Neutralizing Antibodies ◽  
Cell Entry ◽  
Converting Enzyme ◽  
Sars Coronavirus ◽  
Angiotensin Converting Enzyme 2 ◽  
Infected People ◽  
Critical Attention ◽  
Novel Coronavirus

Seventeen years after the epidemic of SARS coronavirus, a novel coronavirus SARS-CoV-2-emerged resulting in an unprecedented pandemic. Angiotensin-converting enzyme 2 (ACE2) is an essential receptor for cell entry of SARS-CoV-2 as well as the SARS coronavirus. Despite many similarities to SARS coronavirus, SARS-CoV-2 exhibits a higher affinity to ACE2 and shows higher infectivity and transmissibility, resulting in explosive increase of infected people and COVID-19 patients. Emergence of the variants harboring mutations in the receptor-binding domain of the Spike protein has drawn critical attention to the interaction between ACE2 and Spike and the efficacies of vaccines and neutralizing antibodies. ACE2 is a carboxypeptidase which degrades angiotensin II, B1-bradykinin, or apelin, and thereby is a critical regulator of cardiovascular physiology and pathology. In addition, the enzymatic activity of ACE2 is protective against acute respiratory distress syndrome (ARDS) caused by viral and non-viral pneumonias, aspiration, or sepsis. Upon infection, both SARS-CoV-2 and SARS coronaviruses downregulates ACE2 expression, likely associated with the pathogenesis of ARDS. Thus, ACE2 is not only the SARS-CoV-2 receptor but might also play an important role in multiple aspects of COVID-19 pathogenesis and possibly post-COVID-19 syndromes. Soluble forms of recombinant ACE2 are currently utilized as a pan-variant decoy to neutralize SARS-CoV-2 and a supplementation of ACE2 carboxypeptidase activity. Here, we review the role of ACE2 in the pathology of ARDS in COVID-19 and the potential application of recombinant ACE2 protein for treating COVID-19.

scholarly journals Naturally mutated spike proteins of SARS-CoV-2 variants show differential levels of cell entry

2020 ◽  
Author(s):  
Seiya Ozono ◽  
Yanzhao Zhang ◽  
Hirotaka Ode ◽  
Toong Seng Tan ◽  
Kazuo Imai ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Angiotensin Converting Enzyme ◽  
Causative Agent ◽  
Cell Entry ◽  
Viral Infectivity ◽  
Converting Enzyme ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Naturally Occurring ◽  
Spike Proteins

AbstractThe causative agent of the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is steadily mutating during continuous transmission among humans. Such mutations can occur in the spike (S) protein that binds to the angiotensin-converting enzyme-2 (ACE2) receptor and is cleaved by transmembrane protease serine 2 (TMPRSS2). However, whether S mutations affect SARS-CoV-2 infectivity remains unknown. Here, we show that naturally occurring S mutations can reduce or enhance cell entry via ACE2 and TMPRSS2. A SARS-CoV-2 S-pseudotyped lentivirus exhibits substantially lower entry than SARS-CoV S. Among S variants, the D614G mutant shows the highest cell entry, as supported by structural observations. Nevertheless, the D614G mutant remains susceptible to neutralization by antisera against prototypic viruses. Taken together, these data indicate that the D614G mutation enhances viral infectivity while maintaining neutralization susceptibility.

Abstract 51: A Critical Role for Outside-In Signaling of Integrin AlphalIIIb/Beta3 in Shear-Dependent Platelet Microvesicle Formation and Phosphatidylerine Exposure

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Aiming Pang ◽  
Yujie Cui ◽  
Michael K Delaney ◽  
Aleksandra Stojanovic-Terpo ◽  
Xiaoping Du
Keyword(s):  
Flow Cytometry ◽  
Shear Stress ◽  
Critical Role ◽  
Selective Inhibitor ◽  
Wild Type ◽  
Activated Platelets ◽  
Binding Function ◽  
Integrin Antagonists ◽  
Dependent Signaling Pathway

Platelets promote coagulation mainly by exposing membrane phosphatidylserine (PS) and releasing PS-expressing microvesicles (MV). We have recently shown that PS exposure and MV release induced by platelet agonists requires shear stress. To identify the receptor responsible for the shear-dependent signaling leading to PS exposure and MV release, we compared platelets from β 3 -/- mice and wild-type mice in MV release and PS exposure under defined shear stress introduced using a cone-plate rheometer. MV release and PS exposure were determined using flow cytometry. Shear-dependent PS exposure and MV release were significantly suppressed in β 3 -/- platelets. Similarly, Wild type platelets treated with integrin antagonists also showed defective PS exposure and MV release. These data indicate an important role for the ligand binding function of integrin αιιb/β3 in shear-dependent MV release and PS exposure. To determine whether the role of integrin αιιb/β3 is due to its outside-in signaling, β 3 -/- platelets were transplanted with wild type β 3 or a mutant β 3 with the critical Gα13 binding site of the β 3 cytoplasmic domain (EEE) changed to alanines (AAA), which was previously shown to selectively abolish outside-in signaling of αIIb/β 3 . Transplantation of wild type β 3 rescued the defective MVs release and PS exposure of β 3 -/- platelets. In contrast, AAA mutant failed to rescue these defects. Consistently, wild type platelets treated with the selective inhibitor of Gα13-integrin interaction, inhibited integrin outside-in signaling and also PS exposure and MV release under shear stress. Furthermore, we also showed that the inhibition of Src, which is important in outside-in signaling downtream of Gα13, also abolished shear-dependent MV release and PS exposure. These data suggest that integrin outside-in signaling mediated by the Gα13-β 3 interaction and Src-dependent signaling pathway plays an important role in transmitting shear-induced mechanical signals leading to MV release and PS exposure in activated platelets.

Abstract 12928: Vascular Complications in Covid-19 and Role of Zinc in Viral Inhibition

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Donghui Zhu ◽  
Zhen Zhao
Keyword(s):  
Viral Entry ◽  
Vascular Complications ◽  
Functional Change ◽  
Cell Entry ◽  
Host Cells ◽  
Binding Motif ◽  
Vascular Cells ◽  
Viral Inhibition ◽  
S Protein

Although COVID-19 is associated with severe respiratory dysfunctions, conspicuous vascular complications and neurological manifestations have been reported worldwide. Of note, two distinctive features have been noticed in severe patients, progressive increase of inflammation and an unusual trend of hypercoagulation. Interestingly, evidence is mounting that healthy blood vessels protect children from serious effects of COVID-19, such as stroke. These findings suggest vascular complications play a key role in the progress of COVID-19, warranting an investigation to its pathophysiology and treatment strategy related to vascular cells. Cell entry of this SARS-CoV-2 virus depends on binding of the viral spike (S) proteins to cellular receptor ACE2, which could be a key target for blocking the viral entry into host cells. ACE2 is a zinc (Zn) binding metallopeptidase while Zn possesses distinct antiviral properties against many human viruses including coronaviruses. Although the mechanistic studies are lacking, Zn appears to inhibit viral protease and polymerase enzymatic processes, and physical processes such as virus attachment, cell entry, and uncoating. In fact, our data showed that ACE2 has multiple affinity binding sites for Zn. Excess bindings of ionic Zn to ACE2 led to its conformational or functional change, therefore, interfering with its ability to metabolize its substrate as well as inhibiting its binding to S protein. Computational modeling also revealed that one critical Zn binding motif is located in ACE2’s binding domain to S protein, and docking affinity of S protein to ACE2 was significantly reduced after Zn binding to this specific site. Moreover, cell and animal studies using pseudo-virus bearing CoV-2-S protein validated that significantly lower infection of vascular cells in the presence of Zn was observed. Thus, targeting vascular complications in COVID-19 may offer strong benefits including the potential therapeutic role of Zn.

scholarly journals When Off Target Effects Are On Target: The Role Of Spironolactone In Patients With COVID-19

2021 ◽  
Author(s):  
Christopher Stuart Wilcox ◽  
Bertram Pitt
Keyword(s):  
Cell Entry ◽  
Pubmed Central ◽  
Angiotensin Converting Enzyme 2 ◽  
Randomized Controlled Clinical Trials ◽  
Loss Of Libido ◽  
Viral Cell Entry ◽  
Poor Tolerability ◽  
Positive Results ◽  
Target Effects

Aims: Spironolactone is a steroidal mineralocoricosteroid receptor antagonist (MRA) used for treatment of resistant hypertension, heart failure and edema. It exerts class specific adverse effects that are shared by other MRAs. Additionally, it exerts unique “off target” steroidal effects that include gynecomastia, impotence and loss of libido in males and menstrual irregularity in females. Together, these have led to a poor tolerability and limited use despite positive results in many randomized, controlled clinical trials. We review the off-target effects of spironolactone that may summate with its MRA action to provide an advantageous profile for prevention or treatment of patients with COVID-19. Methods: Literature review using PubMed Central. Results: The blockade by spironolactone of the androgen receptor should diminish the expression of transmembrane protease serine 2 (TMPRSS2) that has an androgen promoter while its MRA action should enhance the expression of protease nexin1 (PN1) that inhibits furin and plasmin. TMPRSS2, furin and plasmin cooperated to process the SARS-CoV-2 spike protein to increase its high affinity binding to the angiotensin converting enzyme 2 (ACE2) and thereby promote viral cell entry. Its actions as an MRA may reduce inflammation and preserve pulmonary, cardiac and vascular functions. Its anti-plasmin action may combat hemostatic dysfunction. Conclusion: The hypothesis that the off-target effects of spironolactone summate with its MRA actions to provide special benefits for COVID-19 is worthy of direct investigation and clinical trial.

scholarly journals S494 O-glycosylation site on the SARS-COV-2 RBD Affects the Virus Affinity to ACE2 and its Infectivity; A Molecular Dynamics Study

2020 ◽  
Author(s):  
Shadi Rahnama ◽  
Maryam Azimzadeh Irani ◽  
Mehriar Amininasab ◽  
Mohammad Reza Ejtehadi
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Glycosylation Site ◽  
Virus Infectivity ◽  
Free Energies ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Host Interaction ◽  
Binding Free Energies

AbstractSARS-COV-2 is a strain of Coronavirus family which caused the extensive pandemic of COVID-19, which is still going on. Several studies showed that the glycosylation of virus spike (S) protein and the Angiotensin-Converting Enzyme 2 (ACE2) receptor on the host cell is critical for the virus infectivity. Molecular Dynamics (MD) simulations were used to explore the role of a novel mutated O-glycosylation site (D494S) on the Receptor Binding Domain (RBD) of S protein. This site was suggested as a key mediator of virus-host interaction. We showed that the decoration of S494 with elongated O-glycans results in stabilized interactions on the direct RBD-ACE2 interface with more favorable binding free energies for longer oligosaccharides. Hence, this crucial factor must be taken into account for any further inhibitory approaches towards RBD-ACE2 interaction.

Progress in Studies on Structural and Remedial Aspects of Newly Born Coronavirus, SARS-CoV-2

2020 ◽  
Vol 20 (26) ◽  
pp. 2362-2378
Author(s):  
Satya P. Gupta
Keyword(s):  
Vaccine Development ◽  
Cell Receptor ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
N Protein ◽  
Host Cell Receptor ◽  
The Status ◽  
Novel Coronavirus

The article highlights an up-to-date progress in studies on structural and the remedial aspects of novel coronavirus 2019-nCoV, renamed as SARS-CoV-2, leading to the disease COVID-19, a pandemic. In general, all CoVs including SARS-CoV-2 are spherical positive single-stranded RNA viruses containing spike (S) protein, envelope (E) protein, nucleocapsid (N) protein, and membrane (M) protein, where S protein has a Receptor-binding Domain (RBD) that mediates the binding to host cell receptor, Angiotensin Converting Enzyme 2 (ACE2). The article details the repurposing of some drugs to be tried for COVID-19 and presents the status of vaccine development so far. Besides drugs and vaccines, the role of Convalescent Plasma (CP) therapy to treat COVID-19 is also discussed.

Interaction Between Coronavirus S-Protein and Human ACE2: Hints for Exploring Efficient Therapeutic Targets to Treat COVID-19

Angiology ◽  
2020 ◽  
pp. 000331972095228
Author(s):  
Amir Abbas Momtazi-Borojeni ◽  
Maciej Banach ◽  
Željko Reiner ◽  
Matteo Pirro ◽  
Vanessa Bianconi ◽  
...  
Keyword(s):  
Therapeutic Targets ◽  
Renin Angiotensin System ◽  
Protein S ◽  
Surface Proteins ◽  
World Health ◽  
Severe Illness ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Health Organization

With the global expansion of coronavirus disease 2019 (COVID-19) and the declaration of its outbreak as a Public Health Emergency of International Concern by the World Health Organization, there is an urgent need for vaccines and medicines to prevent and treat COVID-19. The responsible pathogen for the disease is the newly severe acute respiratory syndrome coronavirus (SARS-CoV) 2 belonging to the same family of viruses SARS-CoV and Middle East respiratory syndrome coronavirus that originally are zoonotic and have been associated with severe illness during the outbreaks in 2003 and 2012, respectively. The virulence of coronavirus strains is mainly associated with variations in surface proteins mediating cellular entry of the virus, which can help in finding effective therapeutic targets. In this review, we seek evidence showing the role of coronavirus spike protein (S-protein) and its potential cellular receptor, angiotensin-converting enzyme 2 (ACE2), during infection of coronaviruses, including the newly SARS-CoV-2 and its similar strain SARS-CoV. This review also discusses the therapeutic effect of inhibiting the renin–angiotensin system cascade, a target of ACE2, in patients having coronavirus with cardiovascular disease.

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