This AOP is licensed under a Creative Commons Attribution 4.0 International License.
Binding of viral S-glycoprotein to ACE2 receptor leading to acute respiratory distress associated mortality
Point of Contact
- Young Jun Kim
- Brigitte Landesmann
- Penny Nymark
- Shihori Tanabe
- Gillina Bezemer
- Julija Filipovska
- Evgeniia Kazymova
|Author status||OECD status||OECD project||SAAOP status|
|Open for comment. Do not cite|
This AOP was last modified on April 05, 2021 18:16
|Increased, secretion of proinflammatory and profibrotic mediators||October 30, 2019 11:28|
|Increased viral entry and gene expression||March 30, 2021 22:01|
|ACE2 binding to viral S-protein||February 23, 2021 04:44|
|Increase, the risk of acute respiratory failure||March 10, 2020 02:05|
|Increased inflammatory immune responses||January 21, 2021 03:35|
|Increased Mortality||November 30, 2020 04:14|
|Induced Toll Like Receptor (TLR) Dysregulation||March 31, 2021 03:49|
|ACE2 binding to viral S-protein leads to Increased viral entry and gene expression||March 02, 2020 03:19|
|Increased viral entry and gene expression leads to Increased proinflammatory mediators||March 01, 2020 10:31|
|Increased proinflammatory mediators leads to Increased inflammatory immune responses||March 10, 2020 02:18|
|Increased inflammatory immune responses leads to Increase, the risk of acute respiratory failure||March 10, 2020 02:19|
|Increase, the risk of acute respiratory failure leads to Increased Mortality||May 13, 2020 09:39|
|Increased viral entry and gene expression leads to TLR Activation/Dysregulation||March 29, 2021 06:43|
|TLR Activation/Dysregulation leads to Increased proinflammatory mediators||March 29, 2021 06:48|
|SARS-CoV||March 01, 2020 10:42|
|COVID-19||March 01, 2020 10:46|
|HCoV-NL63||February 07, 2021 07:01|
|Sars-CoV-2||February 23, 2021 04:50|
Inhalation of substances, including viral particles, the RNA virus capsid (S) glycoprotein binds the cellular receptor angiotensin-converting enzyme 2 (ACE2) and mediates fusion of the viral and cellular membranes through a pre- to postfusion conformation transition. The S protein is cleaved into S1 and S2 units by a human cell-derived protease (proteolytic enzyme) that is assumed to be Furin.S1 units then binds to its receptor, ACE2. The other fragment, S2, is cleaved by TMPRSS2, a human cell surface serine protease, resulting in cell membrane fusion. The S protein binds the catalytic domain of ACE2 with high affinities likewise, COVID-19 shares 79.6% homology of SARS-CoV and 96% identical at the whole-genome level to a bat coronavirus. Binding of the coronavirus S protein to ACE2 triggers a conformational change in the S protein of the coronavirus, allowing for proteolytic digestion by host cell proteases called TMPRSS2. The AOP report the S glycoprotein of viral capsid in complex with its host cell receptor ACE2 resulted in acute respiratory distress associated mortality by cytokine storms and enhanced inflammation in pulmonary tissue. S-glycoprotein of the virus uses ACE2 to get into cells that are found on the surface of epithelial cells in Kidney, Heart, and Lung. However, there is an unexplored relationship for ACE2 levels between fibrotic hypersensitivity and Renin-Angiotensin Pathway which caused acute respiratory distress associated mortality.
The ACE2 gene encodes the angiotensin-converting enzyme-2, which has been proved to be the receptor for both the SARS-coronavirus (SARS-CoV) and the human respiratory coronavirus. ACE2 is a key component of blood pressure regulation in the renin-angiotensin system. Angiotensin (Ang) converting enzyme 2 (ACE2) is a homolog of ACE. ACE2 negatively regulates the renin-angiotensin system (RAS) by converting Ang II to Ang-(1-7) and AngI to Ang(1-9). The higher levels of receptor expression achieved by expression of recombinant ACE2 could be relevant for cell-cell fusion. The underlying mechanisms remain to be elucidated and could play a role in the entry of the cell-free virus into cells and finally increase the acute respiratory distress associated mortality.
Summary of the AOP
Molecular Initiating Events (MIE)
Key Events (KE)
Adverse Outcomes (AO)
|Sequence||Type||Event ID||Title||Short name|
|MIE||1739||ACE2 binding to viral S-protein||ACE2 binding to viral S-protein|
|KE||1738||Increased viral entry and gene expression||Increased viral entry and gene expression|
|KE||1848||Induced Toll Like Receptor (TLR) Dysregulation||TLR Activation/Dysregulation|
|KE||1496||Increased, secretion of proinflammatory and profibrotic mediators||Increased proinflammatory mediators|
|KE||1750||Increased inflammatory immune responses||Increased inflammatory immune responses|
|KE||1748||Increase, the risk of acute respiratory failure||Increase, the risk of acute respiratory failure|
|AO||351||Increased Mortality||Increased Mortality|
Relationships Between Two Key Events (Including MIEs and AOs)
|ACE2 binding to viral S-protein leads to Increased viral entry and gene expression||adjacent||High||High|
|Increased viral entry and gene expression leads to Increased proinflammatory mediators||adjacent||Low||Low|
|Increased proinflammatory mediators leads to Increased inflammatory immune responses||adjacent||High||Low|
|Increased inflammatory immune responses leads to Increase, the risk of acute respiratory failure||adjacent||Moderate||Low|
|Increase, the risk of acute respiratory failure leads to Increased Mortality||adjacent||High||High|
|Increased viral entry and gene expression leads to TLR Activation/Dysregulation||adjacent||High||Not Specified|
|TLR Activation/Dysregulation leads to Increased proinflammatory mediators||adjacent||High||Not Specified|
Life Stage Applicability
|Conception to < Fetal||High|
|Homo sapiens||Homo sapiens||Moderate||NCBI|
Overall Assessment of the AOP
Domain of Applicability
Essentiality of the Key Events
Considerations for Potential Applications of the AOP (optional)
This AOP not only contributes new tools to study entry of the viral particles into cells and localize its receptor-binding domain of ACE2 but also could serve in the development of novel vaccine immunogens against TMPRSS2 proteases which may inhibit cell entry of COVID-19.
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