SARS-CoV-2 Model for Vaccine Immunogenicity, Safety and ACE2 Modulation Testing

SARS-CoV-2 the causative agent of COVID-19 was first  detected in Wuhan, China, in December 2019. Hoffmann et al., 2020, established that SARS-CoV-2 depends on angiotensin-converting enzyme 2 (ACE2) for entry into cells. ACE2 is a type I transmembrane metallocarboxypeptidase predominantly expressed in vascular endothelial cells, the renal tubular epithelium, and in Leydig cells in the testes. The sequence alignment of human ACE2 UniProtKB - Q9BYF1 (ACE2_HUMAN) and zebrafish ACE2 UniProtKB - E7F9E5 (E7F9E5_DANRE) indicates that the three domains responsible for Interaction with SARS-CoV-2 spike glycoprotein are conserved.

 

Zebrafish      K F D E E A I M Y    Y P   D F R I M C

Human         K F N H E A L F Y    Y P   D F R I M C

 

Pentagrit SARS-CoV-2 Zebrafish model uses the human SARS-CoV-2 Antigen to evoke an immunopathological response creating a similar disease mileu with an average assay reporting turnaround period of 96 hours. The ability of zebrafish to recapitulate mammalian infection of virus and sensitivity to drug treatment was established by Gabor et al., 2014. The disease phenotype of virus infected zebrafish was marked by pericardial edema, yolk sac edema, craniofacial abnormalities and arched back. SARS-CoV-2 antigen driven immune response in zebrafish displayed below indicates a similar disease phenotype with pericardial edema (red arrow), yolk sac edema (yellow arrow), craniofacial abnormalities (blue arrow)and arched back.

 

                         

                     

                            Disease Phenotype of Pentagrit SARS-CoV-2 model

 

Assays

1. Vaccine Immunogenicity Testing of SARS-CoV-2

2. Vaccine Efficacy Testing through Lethal Challenge with SARS-CoV-2 Antigen

3. Vaccine Safety screens of Physiological function, Pathological and Survival

4. Tissue Profile of Active ACE2                           

           

 Pentagrit SARS-CoV-2 Model has been successfully employed to screen for various programmes 

1.) Vaccines Immunogenicity and Safety Testing

2.) Drugs that Modulate ACE2

2.) Re-positioned drugs that slow down or prevent viral entry

3.) Drugs that slow down viral spread and replication

ACE2 expression in the lung, kidney, and gastrointestinal tract, tissues with the ability to harbor SARS-CoV was discussed by Kuba et al., 2010. The rational for ACE2 as a pharmaceutical target for COVID-19 therapies was provided by Zhang et al., 2020, indicating various potential therapeutic applications with ACE2 as a target.  This was further validated in a clinical trial setting by Khan et al., 2017 demonstrating the postulate that repleting ACE2 using a recombinant form of human angiotensin-converting enzyme could attenuate acute lung injury in acute respiratory distress syndrome  establishing ACE2 as the potential target.

Zebrafish models have potential for screening drugs and vaccines with an established translation pathway to humans. The sensitivity of the model allows it to differentiate picogram impact of doses on efficacy and call out adverse events of the organs or physiology at early stages. These hallmarks of the model offers researchers a quick and accurate route to identifying the right potential candidates in drug discovery empowering an overall success of clinical programme.

References

1.Crim MJ, Riley LK. Viral diseases in zebrafish: what is known and unknown. ILAR J. 2012;53(2):135–143. doi:10.1093/ilar.53.2.135

2.Gabor KA, Goody MF, Mowel WK, et al. Influenza A virus infection in zebrafish recapitulates mammalian infection and sensitivity to anti-influenza drug treatment. Dis Model Mech. 2014;7(11):1227–1237. doi:10.1242/dmm.014746

3.Hoffmann M, Kleine-Weber H, Schroeder S, et al. SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSS2 and Is Blocked by a Clinically Proven Protease Inhibitor [published online ahead of print, 2020 Mar 4]. Cell. 2020;S0092-8674(20)30229-4. doi:10.1016/j.cell.2020.02.052

4.Kuba K, Imai Y, Ohto-Nakanishi T, Penninger JM. Trilogy of ACE2: a peptidase in the renin-angiotensin system, a SARS receptor, and a partner for amino acid transporters. Pharmacol Ther. 2010;128(1):119–128. doi:10.1016/j.pharmthera.2010.06.003

5.Yang P, Gu H, Zhao Z, et al. Angiotensin-converting enzyme 2 (ACE2) mediates influenza H7N9 virus-induced acute lung injury. Sci Rep. 2014;4:7027. Published 2014 Nov 13. doi:10.1038/srep07027

6.Zhang H, Penninger JM, Li Y, Zhong N, Slutsky AS. Angiotensin-converting enzyme 2 (ACE2) as a SARS-CoV-2 receptor: molecular mechanisms and potential therapeutic target. Intensive Care Med. 2020;46(4):586–590. doi:10.1007/s00134-020-05985-9

7.Li T, Lu H, Zhang W. Clinical observation and management of COVID-19 patients. Emerg Microbes Infect. 2020;9(1):687–690. doi:10.1080/22221751.2020.1741327

8. Renhong Yan, Yuanyuan Zhang, Yaning Li, Lu Xia, Qiang Zhou. Structure of dimeric full-length human ACE2  in complex with B0AT1. bioRxiv/doi: https://doi.org/10.1101/2020.02.17.951848

9. Molecular docking show SARS-CoV-2 inhibition by Linebacker & Equivir.Biospectrum Asia, Published 2020 Mar 18.

10.Vanessa Monteil, Hyesoo Kwon, Patricia Prado, Astrid Hagelkrüys , Reiner A. Wimmer, Martin Stahl, Alexandra Leopoldi, Elena Garreta, Carmen Hurtado del Pozo, Felipe Prosper, J.P. Romero, Gerald Wirnsberger, Haibo Zhang, Arthur S. Slutsky, Ryan Conder, Nuria Montserrat, Ali Mirazimi, Josef M. Penninger, Inhibition of SARS-CoV-2 infections in engineered human tissues using clinical-grade soluble human ACE2. Cell Press, DOI: 10.1016/j.cell.2020.04.004