No abstract

Novel double-stranded RNA (dsRNA)-binding molecules were developed for the effective thermodynamic and biological stabilization of nucleic acids including short interfering RNAs (siRNAs). β-(1→4)-Linked-2,6-diamino-2,6-dideoxy-d-galactopyranose oligomers (ODAGals) were synthesized for this purpose, and their binding ability with dsRNAs was evaluated. Fluorescence anisotropy measurements showed the 3mer and 4mer of ODAGals to be strongly bound (K < 0.02 μM). The UV melting experiments demonstrated that the binding of ODAGals to dsRNAs proceeded with significant thermodynamic stabilization of the duplexes. Furthermore, the 4mer of ODAGal was clearly revealed to almost completely protect siRNAs with a low N/P ratio (i.e., N in the oligocationic molecule to P in the siRNA ratio) from cleavage by RNase A. On the basis of these results, ODAGals can serve as promising stabilizers or carriers of dsRNA-based drugs such as RNAi drugs.

AntimiR is an antisense oligonucleotide that has been developed to silence microRNA (miRNA) for the treatment of intractable diseases. Enhancement of its in vivo efficacy and improvement of its toxicity are highly desirable but remain challenging. We here design heteroduplex oligonucleotide (HDO)-antimiR as a new technology comprising an antimiR and its complementary RNA. HDO-antimiR binds targeted miRNA in vivo more efficiently by 12-fold than the parent single-stranded antimiR. HDO-antimiR also produced enhanced phenotypic effects in mice with upregulated expression of miRNA-targeting messenger RNAs. In addition, we demonstrated that the enhanced potency of HDO-antimiR was not explained by its bio-stability or delivery to the targeted cell, but reflected an improved intracellular potency. Our findings provide new insights into biology of miRNA silencing by double-stranded oligonucleotides and support the in vivo potential of this technology based on a new class of for the treatment of miRNA-related diseases.