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 potent anti-SARS-CoV-2 effect of siRNA both in vitroand in vivo .
Methods. To identify 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 have shown
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 total lung
inflammation in the animals exposed by inhalation of siR-7-EM/KK-46in vivo .
Conclusions. Thus, we developed a therapeutic strategy for
COVID-19 based on inhalation of a modified siRNA-peptide dendrimer
formulation.
Key words: COVID-19, LNA, peptide dendrimers, SARS-CoV-2,
siRNA.