Peptide Spiders: Peptide-Polymer Conjugates to Traffic Nucleic Acids

Area of Science:

• Biomaterials Science
• Nanotechnology
• Molecular Biology

Background:

• Therapeutic nucleic acids offer potential for genetic disease treatment but face delivery challenges.
• Peptides can facilitate nucleic acid delivery by overcoming biological barriers.
• Balancing stability and biological function in peptide-nucleic acid nanocomplexes is critical.

Purpose of the Study:

• To create and evaluate novel peptide-polymer conjugates, termed "peptide spiders," for enhanced nucleic acid delivery.
• To investigate the impact of different peptide building blocks (targeting ligands, intracellular trafficking peptides) and linkage chemistries (reducible vs. nonreducible) on delivery efficiency.
• To assess the in vivo performance, including pharmacokinetics and gene silencing efficacy, of these nanomaterials in a mouse cancer model.

Main Methods:

• Grafting targeting ligands and intracellular trafficking peptides onto a polyethylene glycol (PEG) backbone to form "peptide spiders."
• Linking peptides to the PEG backbone using nonreducible or reducible chemistries.
• Evaluating the delivery of silencing RNAs into mammalian cells, in vitro gene silencing, and in vivo pharmacokinetics and efficacy in a mouse cancer model.

Main Results:

• Peptide spiders achieved stability through PEG shielding and potential multivalent binding effects.
• While reducible linkages showed higher in vitro potency for gene silencing, nonreducible linkages were more effective in vivo.
• The study demonstrated the potential of these peptide-polymer nanomaterials for delivering nucleic acids and silencing targets in a preclinical cancer model.

Conclusions:

• Peptide spiders represent a promising platform for therapeutic nucleic acid delivery, offering tunable stability and function.
• The choice of linkage chemistry significantly impacts in vitro versus in vivo gene silencing efficacy.
• This work provides valuable insights into the design of peptide-based delivery systems for genetic medicine and cancer therapy.