scholarly journals SARS-CoV-2 entry sites are present in all structural elements of the human glossopharyngeal and vagal nerves: clinical implications

2022 ◽  
Author(s):  
Eva Mezey ◽  
Lynn Vitale-Cross ◽  
Ildiko Szalayova ◽  
Aiden Scoggins ◽  
Miklos Palkovits
Keyword(s):  
Viral Entry ◽  
Cranial Nerves ◽  
Structural Elements ◽  
Olfactory Neurons ◽  
Angiotensin Converting Enzyme 2 ◽  
Respiratory Problems ◽  
Viral Spread ◽  
Protein Receptor ◽  
Two Samples ◽  
Vagal Nerves

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) infections result in the temporary loss of smell and taste (anosmia and dysgeusia) in about one third of confirmed cases. Several investigators have reported that the viral spike protein receptor is present in olfactory neurons. However, no study has been published to date showing the presence of viral entry sites angiotensin-converting enzyme 2 (ACE2), neuropilin1 (NRP1), and TMPRSS2, the serine protease necessary for priming the viral proteins, in human nerves that are responsible for taste sensation (cranial nerves: VII, IX and X). We used immunocytochemistry to examine three postmortem donor samples of the IXth (glossopharyngeal) and Xth (vagal) cranial nerves where they leave/join the medulla from three donors to confirm the presence of ACE2, NRP1 and TMPRSS2. Two samples were paraffin embedded; one was a frozen sample. In addition to staining sections from the latter, we isolated RNA from it, made cDNA, and performed PCR to confirm the presence of the mRNAs that encode the proteins visualized. All three of the proteins required for SARS-CoV-2 infections appear to be present in the human IXth and Xth nerves near the medulla. Direct infection of these nerves by the COVID-19 virus is likely to cause the loss of taste experienced by many patients. In addition, potential viral spread through these nerves into the adjacent brainstem respiratory centers might also aggravate the respiratory problems patients are experiencing.

scholarly journals A SARS-CoV-2 serological assay to determine the presence of blocking antibodies that compete for human ACE2 binding

2020 ◽  
Author(s):  
James R. Byrnes ◽  
Xin X. Zhou ◽  
Irene Lui ◽  
Susanna K. Elledge ◽  
Jeff E. Glasgow ◽  
...  
Keyword(s):  
Viral Entry ◽  
Humoral Response ◽  
Spike Protein ◽  
Block Interaction ◽  
Serological Assay ◽  
Angiotensin Converting Enzyme 2 ◽  
Protein Receptor ◽  
Neutralizing Capacity ◽  
High Throughput Method ◽  
Blocking Antibodies

ABSTRACTAs SARS-CoV-2 continues to spread around the world, there is an urgent need for new assay formats to characterize the humoral response to infection. Convalescent serum is being used for treatment and for isolation of patient-derived antibodies. However, currently there is not a simple means to estimate serum bulk neutralizing capability. Here we present an efficient competitive serological assay that can simultaneously determine an individual’s seropositivity against the SARS-CoV-2 Spike protein and estimate the neutralizing capacity of anti-Spike antibodies to block interaction with the human angiotensin converting enzyme 2 (ACE2) required for viral entry. In this ELISA-based assay, we present natively-folded viral Spike protein receptor binding domain (RBD)-containing antigens via avidin-biotin interactions. Sera are then supplemented with soluble ACE2-Fc to compete for RBD-binding serum antibodies, and antibody binding quantified. Comparison of signal from untreated serum and ACE2-Fc-treated serum reveals the presence of antibodies that compete with ACE2 for RBD binding, as evidenced by loss of signal with ACE2-Fc treatment. In our test cohort of nine convalescent SARS-CoV-2 patients, we found all patients had developed anti-RBD antibodies targeting the epitope responsible for ACE2 engagement. This assay provides a simple and high-throughput method to screen patient sera for potentially neutralizing anti-Spike antibodies to enable identification of candidate sera for therapeutic use.

scholarly journals Gene of the month: TMPRSS2 (transmembrane serine protease 2)

2020 ◽  
Vol 73 (12) ◽  
pp. 773-776 ◽  
Author(s):  
Michelle Thunders ◽  
Brett Delahunt
Keyword(s):  
Serine Protease ◽  
Viral Entry ◽  
Fusion Gene ◽  
Related Gene ◽  
Diverse Range ◽  
Angiotensin Converting Enzyme 2 ◽  
Viral Spread ◽  
Transmembrane Serine Protease ◽  
Oncogenic Transcription Factor

Transmembrane serine protease 2 is encoded by the TMPRSS2 gene. The gene is widely conserved and has two isoforms, both being autocatalytically activated from the inactive zymogen form. A fusion gene between the TMPRSS2 gene and ERG (erythroblast-specific-related gene), an oncogenic transcription factor, is the most common chromosomal aberration detected in prostate cancer, responsible for driving carcinogenesis. The other key role of TMPRSS2 is in priming the viral spike protein which facilitates viral entry essential for viral infectivity. The protease activates a diverse range of viruses. Both SARS-CoV and SARS-CoV-2 (COVID-19) use angiotensin-converting enzyme 2 (ACE2) and TMPRSS2 to facilitate entry to cells, but with SARS-CoV-2 human-to-human transmission is much higher than SARS-CoV. As TMPRSS2 is expressed outside of the lung, and can therefore contribute to extrapulmonary spread of viruses, it warrants further exploration as a potential target for limiting viral spread and infectivity.

scholarly journals Competitive SARS-CoV-2 Serology Reveals Most Antibodies Targeting the Spike Receptor-Binding Domain Compete for ACE2 Binding

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
James R. Byrnes ◽  
Xin X. Zhou ◽  
Irene Lui ◽  
Susanna K. Elledge ◽  
Jeff E. Glasgow ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Receptor Binding ◽  
Viral Entry ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Converting Enzyme ◽  
Block Interaction ◽  
Angiotensin Converting Enzyme 2 ◽  
Protein Receptor

ABSTRACT As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread around the world, there is an urgent need for new assay formats to characterize the humoral response to infection. Here, we present an efficient, competitive serological assay that can simultaneously determine an individual’s seroreactivity against the SARS-CoV-2 Spike protein and determine the proportion of anti-Spike antibodies that block interaction with the human angiotensin-converting enzyme 2 (ACE2) required for viral entry. In this approach based on the use of enzyme-linked immunosorbent assays (ELISA), we present natively folded viral Spike protein receptor-binding domain (RBD)-containing antigens via avidin-biotin interactions. Sera are then competed with soluble ACE2-Fc, or with a higher-affinity variant thereof, to determine the proportion of ACE2 blocking anti-RBD antibodies. Assessment of sera from 144 SARS-CoV-2 patients ultimately revealed that a remarkably consistent and high proportion of antibodies in the anti-RBD pool targeted the epitope responsible for ACE2 engagement (83% ± 11%; 50% to 107% signal inhibition in our largest cohort), further underscoring the importance of tailoring vaccines to promote the development of such antibodies. IMPORTANCE With the emergence and continued spread of the SARS-CoV-2 virus, and of the associated disease, coronavirus disease 2019 (COVID-19), there is an urgent need for improved understanding of how the body mounts an immune response to the virus. Here, we developed a competitive SARS-CoV-2 serological assay that can simultaneously determine whether an individual has developed antibodies against the SARS-CoV-2 Spike protein receptor-binding domain (RBD) and measure the proportion of these antibodies that block interaction with the human angiotensin-converting enzyme 2 (ACE2) required for viral entry. Using this assay and 144 SARS-CoV-2 patient serum samples, we found that a majority of anti-RBD antibodies compete for ACE2 binding. These results not only highlight the need to design vaccines to generate such blocking antibodies but also demonstrate the utility of this assay to rapidly screen patient sera for potentially neutralizing antibodies.

scholarly journals Receptor binding and proteolysis do not induce large conformational changes in the SARS-CoV spike

2018 ◽  
Author(s):  
Robert N. Kirchdoerfer ◽  
Nianshuang Wang ◽  
Jesper Pallesen ◽  
Daniel Wrapp ◽  
Hannah L. Turner ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Viral Entry ◽  
Cleavage Site ◽  
Host Protein ◽  
Host Cells ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Protein Receptor ◽  
Proteolytic Cleavages ◽  
Secondary Cleavage

AbstractSevere acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 as a highly transmissible pathogenic human betacoronavirus. The viral spike glycoprotein (S) utilizes angiotensin-converting enzyme 2 (ACE2) as a host protein receptor and mediates fusion of the viral and host membranes, making S essential to viral entry into host cells and host species tropism. As SARS-CoV enters host cells, the viral S undergoes two proteolytic cleavages at S1/S2 and S2’ sites necessary for efficient membrane fusion. Here, we present a cryo-EM analysis of the trimeric SARS-CoV S interactions with ACE2 and of the trypsin-cleaved S. Surprisingly, neither binding to ACE2 nor cleavage by trypsin at the S1/S2 cleavage site impart large conformational changes within S or expose the secondary cleavage site, S2’. These observations suggest that S2’ cleavage does not occur in the S prefusion conformation and that additional triggers may be required.

scholarly journals Diosmectite inhibits the interaction between SARS-CoV-2 and human enterocytes by trapping viral particles, thereby preventing NF-kappaB activation and CXCL10 secretion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marco Poeta ◽  
Valentina Cioffi ◽  
Vittoria Buccigrossi ◽  
Merlin Nanayakkara ◽  
Melissa Baggieri ◽  
...  
Keyword(s):  
Nuclear Factor Kappa B ◽  
Direct Evidence ◽  
Spike Protein ◽  
Gi Tract ◽  
Angiotensin Converting Enzyme 2 ◽  
Viral Spread ◽  
Protein Receptor ◽  
Viral Particles ◽  
Nf Kappab ◽  
Apical Membranes

AbstractSARS-CoV-2 enters the intestine by the spike protein binding to angiotensin-converting enzyme 2 (ACE2) receptors in enterocyte apical membranes, leading to diarrhea in some patients. Early treatment of COVID-19-associated diarrhea could relieve symptoms and limit viral spread within the gastrointestinal (GI) tract. Diosmectite, an aluminomagnesium silicate adsorbent clay with antidiarrheal effects, is recommended in some COVID-19 management protocols. In rotavirus models, diosmectite prevents pathogenic effects by binding the virus and its enterotoxin. We tested the trapping and anti-inflammatory properties of diosmectite in a SARS-CoV-2 model. Trapping effects were tested in Caco-2 cells using spike protein receptor-binding domain (RBD) and heat-inactivated SARS-CoV-2 preparations. Trapping was assessed by immunofluorescence, alone or in the presence of cells. The effect of diosmectite on nuclear factor kappa B (NF-kappaB) activation and CXCL10 secretion induced by the spike protein RBD and heat-inactivated SARS-CoV-2 were analyzed by Western blot and ELISA, respectively. Diosmectite bound the spike protein RBD and SARS-CoV-2 preparation, and inhibited interaction of the spike protein RBD with ACE2 receptors on the Caco-2 cell surface. Diosmectite exposure also inhibited NF-kappaB activation and CXCL10 secretion. These data provide direct evidence that diosmectite can bind SARS-CoV-2 components and inhibit downstream inflammation, supporting a mechanistic rationale for consideration of diosmectite as a management option for COVID-19-associated diarrhea.

scholarly journals Human Immunodeficiency Viruses Pseudotyped with SARS-CoV-2 Spike Proteins Infect a Broad Spectrum of Human Cell Lines through Multiple Entry Mechanisms

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 953
Author(s):  
Chuan Xu ◽  
Annie Wang ◽  
Ke Geng ◽  
William Honnen ◽  
Xuening Wang ◽  
...  
Keyword(s):  
Cell Lines ◽  
Viral Entry ◽  
Broad Spectrum ◽  
A549 Cells ◽  
Cell Types ◽  
Pseudotyped Virus ◽  
Angiotensin Converting Enzyme 2 ◽  
Human Immunodeficiency Viruses ◽  
Tyrosine Protein Kinase ◽  
Overexpressing Cell

Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2), the causative agent of coronavirus disease 19 (COVID-19), enters cells through attachment to the human angiotensin converting enzyme 2 (hACE2) via the receptor-binding domain (RBD) in the surface/spike (S) protein. Several pseudotyped viruses expressing SARS-CoV-2 S proteins are available, but many of these can only infect hACE2-overexpressing cell lines. Here, we report the use of a simple, two-plasmid, pseudotyped virus system comprising a SARS-CoV-2 spike-expressing plasmid and an HIV vector with or without vpr to investigate the SARS-CoV-2 entry event in various cell lines. When an HIV vector without vpr was used, pseudotyped SARS-CoV-2 viruses produced in the presence of fetal bovine serum (FBS) were able to infect only engineered hACE2-overexpressing cell lines, whereas viruses produced under serum-free conditions were able to infect a broader range of cells, including cells without hACE2 overexpression. When an HIV vector containing vpr was used, pseudotyped viruses were able to infect a broad spectrum of cell types regardless of whether viruses were produced in the presence or absence of FBS. Infection sensitivities of various cell types did not correlate with mRNA abundance of hACE2, TMPRSS2, or TMPRSS4. Pseudotyped SARS-CoV-2 viruses and replication-competent SARS-CoV-2 virus were equally sensitive to neutralization by an anti-spike RBD antibody in cells with high abundance of hACE2. However, the anti-spike RBD antibody did not block pseudotyped viral entry into cell lines with low abundance of hACE2. We further found that CD147 was involved in viral entry in A549 cells with low abundance of hACE2. Thus, our assay is useful for drug and antibody screening as well as for investigating cellular receptors, including hACE2, CD147, and tyrosine-protein kinase receptor UFO (AXL), for the SARS-CoV-2 entry event in various cell lines.

scholarly journals Neurological and Neuropsychological Changes Associated with SARS-CoV-2 Infection: New Observations, New Mechanisms

2021 ◽  
pp. 107385842098410
Author(s):  
Muhammad Ali Haidar ◽  
Hussam Jourdi ◽  
Zeinab Haj Hassan ◽  
Ohanes Ashekyan ◽  
Manal Fardoun ◽  
...  
Keyword(s):  
Viral Entry ◽  
Health Workers ◽  
The Elderly ◽  
Circumventricular Organs ◽  
Depression And Anxiety ◽  
Virus Surface ◽  
Angiotensin Converting Enzyme 2 ◽  
Neuropsychological Changes ◽  
High Risk Populations ◽  
The Central Nervous System

SARS-CoV-2 infects cells through angiotensin-converting enzyme 2 (ACE2), a ubiquitous receptor that interacts with the virus’ surface S glycoprotein. Recent reports show that the virus affects the central nervous system (CNS) with symptoms and complications that include dizziness, altered consciousness, encephalitis, and even stroke. These can immerge as indirect immune effects due to increased cytokine production or via direct viral entry into brain tissue. The latter is possible through neuronal access via the olfactory bulb, hematogenous access through immune cells or directly across the blood-brain barrier (BBB), and through the brain’s circumventricular organs characterized by their extensive and highly permeable capillaries. Last, the COVID-19 pandemic increases stress, depression, and anxiety within infected individuals, those in isolation, and high-risk populations like children, the elderly, and health workers. This review surveys the recent updates of CNS manifestations post SARS-CoV-2 infection along with possible mechanisms that lead to them.

scholarly journals The Effects of Aβ1-42 Binding to the SARS-CoV-2 Spike Protein S1 Subunit and Angiotensin-Converting Enzyme 2

2021 ◽  
Vol 22 (15) ◽  
pp. 8226
Author(s):  
John Tsu-An Hsu ◽  
Chih-Feng Tien ◽  
Guann-Yi Yu ◽  
Santai Shen ◽  
Yi-Hsuan Lee ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Viral Entry ◽  
Negative Impact ◽  
Spike Protein ◽  
Infection Model ◽  
Converting Enzyme ◽  
Viral Receptor ◽  
Angiotensin Converting Enzyme 2 ◽  
People With Dementia ◽  
The Impact

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer’s disease (AD), the major form of dementia, β-amyloid (Aβ) levels in the blood are increased; however, the impact of elevated Aβ levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aβ1-42, but not Aβ1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aβ1-42. Furthermore, Aβ1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aβ1-42 show that the clearance of Aβ1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aβ antibody. In conclusion, these findings suggest that the binding of Aβ1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aβ1-42 in the blood is beneficial to the fight against COVID-19 and AD.

scholarly journals ACE2 Shedding and the Role in COVID-19

2022 ◽  
Vol 11 ◽  
Author(s):  
Jieqiong Wang ◽  
Huiying Zhao ◽  
Youzhong An
Keyword(s):  
Amino Acids ◽  
Viral Entry ◽  
Kidney Injury ◽  
Renin Angiotensin System ◽  
Underlying Mechanism ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Angiotensin Converting Enzyme 2 ◽  
Transmembrane Glycoprotein

Angiotensin converting enzyme 2 (ACE2), a transmembrane glycoprotein, is an important part of the renin-angiotensin system (RAS). In the COVID-19 epidemic, it was found to be the receptor of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). ACE2 maintains homeostasis by inhibiting the Ang II-AT1R axis and activating the Ang I (1-7)-MasR axis, protecting against lung, heart and kidney injury. In addition, ACE2 helps transport amino acids across the membrane. ACE2 sheds from the membrane, producing soluble ACE2 (sACE2). Previous studies have pointed out that sACE2 plays a role in the pathology of the disease, but the underlying mechanism is not yet clear. Recent studies have confirmed that sACE2 can also act as the receptor of SARS-COV-2, mediating viral entry into the cell and then spreading to the infective area. Elevated concentrations of sACE2 are more related to disease. Recombinant human ACE2, an exogenous soluble ACE2, can be used to supplement endogenous ACE2. It may represent a potent COVID-19 treatment in the future. However, the specific administration concentration needs to be further investigated.

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