This study demonstrates that novel octenyl-alanine–modified hPep peptides efficiently encapsulate siRNA into well-defined nanoparticles. Our findings highlight the potential of these hPep/siRNA nanoparticles to induce RNA interference, effectively silencing therapeutically important CD45 expression.
ABSTRACT
The development of therapeutic small interfering RNAs (siRNAs) has lately gained significant momentum due to their ability to silence genes in a highly specific manner. The main obstacle withholding the wider translation of siRNA-based drug modalities is their limited half-life and poor bioavailability, especially in extra-hepatic tissues. Consequently, various drug delivery systems (DDSs) have been developed to improve the delivery of siRNAs, including short delivery peptides called cell-penetrating peptides (CPPs). In this study, we explore the potential of using alkenyl-alanine modifications to enhance the siRNA delivery efficacy with CPPs. We demonstrate on hPep peptides that incorporation of alkenyl-alanines enhances the encapsulation of siRNAs into stable nanoparticles and contributes to increased cellular uptake. Furthermore, we demonstrate that the lead peptide, hPep3, induces effective RNAi-mediated gene silencing in a reporter cell model as well as on the disease-implicated endogenous CD45 gene target. The biodistribution studies in mice show that the alkenyl-alanines are systemically well tolerated, and employing such modifications in the peptide backbone improves siRNA delivery in several tissues, including extra-hepatic sites. As demonstrated on hPep peptides, alkenyl-alanines offer a simple yet robust way to enhance the delivery efficacy of CPPs and have the potential to advance siRNA therapeutics beyond the liver targets.
