ABSTRACT
We present a small molecule chemotype, identified by an orthogonal drug screen, exhibiting nanomolar activity against members of all the six viral families causing most human respiratory viral disease, with a demonstrated barrier to resistance development. Antiviral activity is shown in mammalian cells, including human primary bronchial epithelial cells cultured to an air-liquid interface and infected with SARS-CoV-2. In animals, efficacy of early compounds in the lead series is shown by survival (for a coronavirus) and viral load (for a paramyxovirus). The drug target is shown to include a subset of the protein 14-3-3 within a transient host multi-protein complex containing components implicated in viral lifecycles and in innate immunity. This multi-protein complex is modified upon viral infection and largely restored by drug treatment. Our findings suggest a new clinical therapeutic strategy for early treatment upon upper respiratory viral infection to prevent progression to lower respiratory tract or systemic disease. One Sentence SummaryA host-targeted drug to treat all respiratory viruses without viral resistance development.
ABSTRACT
IntroductionCoronavirus disease 2019 (COVID-19) can be associated with mortality and high morbidity worldwide. There is an extensive effort to control infection and disease caused by SARS-CoV-2. This study addressed the hypothesis that angiotensin II type I receptor blocker, Losartan, may restrict pathogenesis caused by SARS-CoV-2 by decreasing viral-induced cytopathological changes by blocking angiotensin II type 1 receptor (AT1R), thus reducing the affinity of the virus for ACE2, and inhibiting papain-like protease of the virus. MethodLosartan inhibitory effect on deubiquitination and deISGylation properties of papain-like protease was investigated using a fluorescence method and gel shift analysis determining its inhibitory effects. The inhibitory effect of Losartan on SARS-CoV-2 cell replication was investigated both when losartan was added to the cell culture 1 hour before (pre-infection group) and 1 hour after (post-infection group) SARS-CoV-2 infection of Vero E6 cells. ResultsLosartan treatment of Vero E6 cells prior to and after SARS-CoV-2 infection reduced SARS-CoV-2 replication by 80% and 70% respectively. Losartan was not a strong deubiquitinase and deISGylase inhibitor of PLpro. ConclusionLosartan added pre- and post-infection to the Vero E6 cell culture significantly prevents cell destruction and replication by SARS-CoV2. Losartan has low side-effects, is readily available, and can be produced at high levels globally, all features of a promising drug in treatment of COVID-19 if validated by clinical trials.
ABSTRACT
SARS-CoV2, the etiologic agent of COVID-19, uses ACE2 as a cell entry receptor. Soluble ACE2 has been shown to have neutralizing antiviral activity but has a short half-life and no active transport mechanism from the circulation into the alveolar spaces of the lung. To overcome this, we constructed an ACE2-human IgG1 fusion protein with mutations in the catalytic domain of ACE2. This fusion protein contained a LALA mutation that abrogates Fcr{gamma} binding, but retains FcRN binding to prolong the half-life, as well as achieve therapeutic concentrations in the lung lavage. Interestingly, a mutation in the catalytic domain of ACE2, MDR504, completely abrogated catalytic activity, but significantly increased binding to SARS-CoV2 spike protein in vitro. This feature correlated with more potent viral neutralization in a plaque assay. Parental administration of the protein showed stable serum concentrations with a serum half-life of [~] 145 hours with excellent bioavailability in the epithelial lining fluid of the lung. Prophylactic administration of MDR504 significantly attenuated SARS-CoV2 infection in a murine model. These data support that the MDR504 hACE2-Fc is an excellent candidate for pre or post-exposure prophylaxis or treatment of COVID-19.
