Evaluation of siRNA nanoformulations and aerosol delivery for treatment of SARS-CoV-2

The 2019 novel coronavirus, SARS-CoV-2 causes COVID-19, a pandemic viral disease. This disease has resulted in world-wide fatalities, particularly in patients with cardiovascular disease, and arterial hypertension. As of June 2020, close to 6.6 million cases and death of 393,000 were reported worldwide; 1.95 million cases and more than 111,000 deaths in the US. COVID-19 poses a specific and substantial immediate burden on cancer patients who are already facing the tribulations of cancer treatment and survivorship. SARS-CoV-2 will continue to be a major threat to the lives of the above high risk groups including current and future cancer patients irrespective of the type and stage of cancer, unless a treatment that does not interfere with current cancer chemotherapies is developed urgently. CoVs are enveloped with a positive sense, single-strand RNA genome; and belong to the Coronaviridae family. CoVs are composed of at least 5 major fundamental proteins: replicase encoding polypeptide (pp1ab), Spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins. The viral life cycle begins with the infection, entry of the virion into cells by the binding to the host cell receptor and endocytosis (S protein), release of the viral genome into the cytoplasm and its transport to the host nucleus (N protein) where it replicates (pp1ab) and new virus particles are released. This results in respiratory, enteric, hepatic, and neurologic diseases. pp1ab, E and N proteins, unique to SARS-CoV-2 and not natively expressed in mammalian cells, offer potential opportunities for therapeutic targeting to cure COVID-19. Current drug and treatment strategies include blocking of RNA-polymerase, mRNA-based vaccines to induce antibody production, antibody treatments, and isolation of plasma and antibodies from the survivors of Covid-19. Since there are several unwarranted side effects of targeting the proteins essential to SARS-CoV-2 infection and spread, limited benefits of the current drugs, and limited availability of COVID-19 disease animal models, our strategy is to use and prioritize siRNA candidates based on the greatest inhibition of SARS-CoV-2 proteins (in model cell lines transfected with individual SARS-CoV-2 proteins) for further evaluation. We aim to use the siRNA-based therapeutic candidates with either an aerosolized (through a collision nebulizer) neutral phospholipid 1,2- dioleoyl-sn-glycero-3-phosphatidylcholine nanoliposomes (DOPC) or plant-derived vesicles (PDV) to specifically target the vital proteins of SARS-CoV-2 to inhibit its replication and virus assembly. We expect this approach will have a potent anti-viral RNAi response leading to viral clearance.