Tomatsidou, A. | Search bioRxiv

bioRxiv2022

Superiority of intranasal over systemic administration of bioengineered soluble ACE2 for survival and brain protection against SARS-CoV-2 infection

The present study was designed to investigate the effects of a soluble ACE2 protein termed ACE2 618-DDC-ABD, bioengineered to have long duration of action and high binding affinity to SARS-CoV-2, when administered either intranasally (IN) or intraperitoneally (IP) and before or after SARS-CoV-2 inoculation. K18hACE2 mice permissive for SARS-CoV-2 infection were inoculated with 2x104 PFU wildtype SARS-CoV-2. In one protocol, ACE2 618-DDC-ABD was given either IN or IP, pre- and post-viral inoculation. In a second protocol, ACE2 618-DDC-ABD was given either IN, IP or IN+IP but only post-viral inoculation. In addition, A549 and Vero E6 cells were used to test neutralization of SARS-CoV-2 variants by ACE2 618-DDC-ABD at different concentrations. Survival by day 5 was 0% in infected untreated mice, and 40% in mice from the ACE2 618-DDC-ABD IP-pre treated group. By contrast, in the IN-pre group survival was 90%, histopathology of brain and kidney was essentially normal and markedly improved in the lungs. When ACE2 618-DDC-ABD was administered only post viral inoculation, survival was 30% in the IN+IP group, 20% in the IN and 0% in the IP group. Brain SARS-CoV-2 titers were high in all groups except for the IN-pre group where titers were undetectable in all mice. In cells permissive for SARS-CoV-2 infection, ACE2 618-DDC-ABD neutralized wildtype SARS-CoV-2 at high concentrations, whereas much lower concentrations neutralized omicron BA. 1. We conclude that ACE2 618-DDC-ABD provides much better survival and organ protection when administered intranasally than when given systemically or after viral inoculation and that lowering brain titers is a critical determinant of survival and organ protection.

pathology↗

bioRxiv2021

A novel soluble ACE2 protein totally protects from lethal disease caused by SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) uses full-length angiotensin converting enzyme 2 (ACE2), which is membrane bound, as its initial cell contact receptor preceding viral entry. Here we report a human soluble ACE2 variant fused with a 5kD albumin binding domain (ABD) and bridged via a dimerization motif hinge-like 4-cysteine dodecapeptide, which we term ACE2 1-618-DDC-ABD. This protein is enzymatically active, has increased duration of action in vivo conferred by the ABD-tag, and displays 20-30-fold higher binding affinity to the SARS-CoV-2 receptor binding domain than its des-DDC monomeric form (ACE2 1-618-ABD) due to DDC-linked dimerization. ACE2 1-618-DDC-ABD was administered for 3 consecutive days to transgenic k18-hACE2 mice, a model that develops lethal SARS-CoV-2 infection, to evaluate the preclinical preventative/ therapeutic value for COVID-19. Mice treated with ACE2 1-618-DDC-ABD developed a mild to moderate disease for the first few days assessed by a clinical score and modest weight loss. The untreated control animals, by contrast, became severely ill and had to be sacrificed by day 6/7 and lung histology revealed extensive pulmonary alveolar hemorrhage and mononuclear infiltrates. At 6 days, mortality was totally prevented in the treated group, lung histopathology was improved and viral titers markedly reduced. This demonstrates for the first time in vivo the preventative/ therapeutic potential of a novel soluble ACE2 protein in a preclinical animal model.

pathology↗