Abstract
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.
Competing Interest Statement
D. Batlle and J. Wysocki are coinventors of patents entitled 'Active Low Molecular Weight Variants of Angiotensin Converting Enzyme 2', 'Active low molecular weight variants of Angiotensin Converting Enzyme 2 (ACE2) for the treatment of diseases and conditions of the eye' and 'Shorter soluble forms of Angiotensin Converting Enzyme 2 (ACE2) for treating and preventing coronavirus infection.' D. Batlle is founder of Angiotensin Therapeutics Inc. D. Batlle has received consulting fees from AstraZeneca, Relypsa, and Tricida, all unrelated to this work. During the conduct of these studies, D. Batlle received unrelated support from National Institute of Diabetes and Digestive and Kidney Diseases grant R01DK104785, as well as from a grant from AstraZeneca; G. Randall reports consultancy agreements with Optikira. J. Wysocki reports scientific advisor capacity for Angiotensin Therapeutics Inc. All remaining authors have nothing to disclose.
Footnotes
Conflict of interest statement: D. Batlle and J. Wysocki are coinventors of patents entitled “Active Low Molecular Weight Variants of Angiotensin Converting Enzyme 2”, “Active low molecular weight variants of Angiotensin Converting Enzyme 2 (ACE2) for the treatment of diseases and conditions of the eye” and “Shorter soluble forms of Angiotensin Converting Enzyme 2 (ACE2) for treating and preventing coronavirus infection.” D. Batlle is founder of Angiotensin Therapeutics Inc. D. Batlle has received consulting fees from AstraZeneca, Relypsa, and Tricida, all unrelated to this work. During the conduct of these studies, D. Batlle received unrelated support from National Institute of Diabetes and Digestive and Kidney Diseases grant R01DK104785, as well as from a grant from AstraZeneca; G. Randall reports consultancy agreements with Optikira. J. Wysocki reports scientific advisor capacity for Angiotensin Therapeutics Inc. All remaining authors have nothing to disclose.
The revision was only to add an author, Haley Gula, that mistakingly had not been included on the original submission.
