In Vivo mRNA Hacking with Staple Oligomers Prevents Myocardial Hypertrophy

Summary paragraphThe elucidation of gene-silencing mechanisms by RNA interference (RNAi) and antisense oligomers has drawn increasing attention to nucleic acid medicine. However, several challenges remain to be overcome, such as in vivo stability1, target selectivity 2,3, drug delivery4,5, and induced innate immunity6. Here, we report a new, versatile, and highly-selective method to hack RNA by controlling RNA structure using short oligonucleotides (RNA hacking: RNAh) in living cells. The oligonucleotide, named Staple oligomer, hybridizes specifically to a target mRNA and artificially induces an RNA higher-order structure, RNA G-quadruplex (RGq)7, on the mRNA. As a result, the RGq allows effective suppression of the target protein translation. This technology does not require cooperation with bioprocesses including enzymatic reactions as in RNAi or antisense technologies, permitting the introduction of artificial nucleic acids into Staple oligomers to increase their in vivo stability without compromising their effectiveness. The method was validated by translational regulation of the mRNAs of TPM3, MYD88, and TRPC6, in a cell-free system and in living mammalian cells. In vivo application of the technology to TRPC6 mRNA allowed us to prevent cardiac hypertrophy in transverse aortic constriction (TAC)-treated mice with no detectable off-target effects. This technology provides new insights into gene therapy after RNAi and antisense technologies.