Amphipathic Octenyl-Alanine Modified Peptides Mediate Effective siRNA Delivery.

Area of Science:

• Biotechnology
• Molecular Biology
• Drug Delivery Systems

Background:

• Therapeutic small interfering RNAs (siRNAs) offer specific gene silencing but face challenges with short half-life and poor bioavailability, particularly outside the liver.
• Cell-penetrating peptides (CPPs) are explored as drug delivery systems (DDSs) to overcome siRNA delivery limitations.

Purpose of the Study:

• To investigate the efficacy of alkenyl-alanine modifications in enhancing CPP-mediated siRNA delivery.
• To assess the impact of these modifications on nanoparticle formation, cellular uptake, gene silencing, and biodistribution.

Main Methods:

• Incorporation of alkenyl-alanine modifications into hPep peptides.
• Evaluation of siRNA encapsulation into stable nanoparticles.
• Assessment of cellular uptake and RNA interference (RNAi)-mediated gene silencing in reporter cell models and on the CD45 gene target.
• Biodistribution studies in mice to evaluate systemic tolerance and tissue delivery.

Main Results:

• Alkenyl-alanine incorporation enhanced siRNA encapsulation into stable nanoparticles and increased cellular uptake.
• The modified hPep3 peptide demonstrated effective RNAi-mediated gene silencing.
• Biodistribution studies confirmed systemic tolerance and improved siRNA delivery to extra-hepatic tissues.
• Alkenyl-alanine modifications improved the overall delivery efficacy of CPPs.

Conclusions:

• Alkenyl-alanine modifications provide a simple and effective strategy to enhance CPP performance for siRNA delivery.
• This approach holds significant potential for advancing siRNA therapeutics beyond liver-targeted applications.
• The findings support the development of novel peptide-based DDSs for challenging therapeutic targets.