Silencing of SARS‐CoV‐2 with modified siRNA‐peptide dendrimer formulation

Abstract

Background: First vaccines for prevention of Coronavirus disease 2019 (COVID-19) are becoming available but there is a huge and unmet need for specific forms of treatment. In this study we aimed to evaluate the anti-SARS-CoV-2 effect of siRNA both in vitro and in vivo.Methods: To identify the most effective molecule out of a panel of 15 in silico designed siRNAs, an in vitro screening system based on vectors expressing SARS-CoV-2 genes fused with the firefly luciferase reporter gene and SARS-CoV-2-infected cells was used. The most potent siRNA, siR-7, was modified by Locked nucleic acids (LNAs) to obtain siR-7-EM with increased stability and was formulated with the peptide dendrimer KK-46 for enhancing cellular uptake to allow topical application by inhalation of the final formulation -siR-7-EM/KK-46. Using the Syrian Hamster model for SARS-CoV-2 infection the antiviral capacity of siR-7-EM/KK-46 complex was evaluated. Results:We identified the siRNA, siR-7, targeting SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) as the most efficient siRNA inhibiting viral replication in vitro.Moreover, we showed that LNA-modification and complexation with the designed peptide dendrimer enhanced the antiviral capacity of siR-7 in vitro. We demonstrated significant reduction of virus titer and lung inflammation in animals exposed to inhalation of siR-7-EM/KK-46 in vivo.Conclusions: Thus, we developed a therapeutic strategy for COVID-19 based on inhalation of a modified siRNA-peptide dendrimer formulation. The developed medication is intended for inhalation treatment of COVID-19 patients. | 2841KHAITOV eT Al.

Inhibition of SARS-CoV-2 Replication by a Small Interfering RNA Targeting the Leader Sequence

“…The siRNA-LNPs robustly repressed virus in the lungs and provided a survival advantage to the treated mice [56]. Another recent in vivo study by Khaitov et al demonstrated that topical application by inhalation of a stabilized siRNA modified with a peptide dendrimer targeting the RdRp of SARS-CoV-2 significantly reduced viral load and inflammation in the lung of a Syrian hamster model [57]. Taken together, these are promising results for the development of RNAi-based therapy of COVID-19.…”

“…For example, nasally applied siRNAs resulted in the highly effective inhibition of respiratory syncytial virus (RSV) and SARS-CoV-1 in animal models [44,67,68]. Nebulizers or inhalers were developed to generate aerosols for drug delivery by inhalation directly to the lung [69] as recently successfully implemented for SARS-CoV-2 inhibition [57]. Administration of an siRNA targeting the RSV N gene (ALN-RSV01) by inhalation for the potential treatment or prevention of RSV infection was also investigated in a clinical study.…”

Nucleic Acid-Based Treatments Against COVID-19: Potential Efficacy of Aptamers and siRNAs

“…The study reported marked repression of virus in the lungs and pronounced survival advantage to the treated mice. Khaitov et al selected a siRNA against the viral RdRp out of 15 in-silico designed siRNAs as the most efficient siRNA inhibiting viral replication in vitro ( Khaitov et al, 2021 ). Moreover, they showed that locked nucleic acids (LNAs) modification increases the RNA stability and complexation with the designed peptide dendrimer (KK-46) enhances cellular uptake to allow topical application by inhalation of the final formulation.…”

Developments in Treatment Methodologies Using Dendrimers for Infectious Diseases

“…These dendrimers proved to be a basis for further research as an antiviral therapy [ 103 ]. Recent studies also showed that topical application by inhalation of peptide dendrimer carrying SARS-CoV-2-specific modified siRNA can potentially be used for the treatment of SARS-CoV-2-induced lung inflammation [ 104 ].…”