An anionic, endosome-escaping polymer to potentiate intracellular delivery of cationic peptides, biomacromolecules, and nanoparticles

Abstract

Peptides and biologics provide unique opportunities to modulate intracellular targets not druggable by conventional small molecules. Most peptides and biologics are fused with cationic uptake moieties or formulated into nanoparticles to facilitate delivery, but these systems typically lack potency due to low uptake and/or entrapment and degradation in endolysosomal compartments. Because most delivery reagents comprise cationic lipids or polymers, there is a lack of reagents specifically optimized to deliver cationic cargo. Herein, we demonstrate the utility of the cytocompatible polymer poly(propylacrylic acid) (PPAA) to potentiate intracellular delivery of cationic biomacromolecules and nano-formulations. This approach demonstrates superior efficacy over all marketed peptide delivery reagents and enhances delivery of nucleic acids and gene editing ribonucleoproteins (RNPs) formulated with both commercially-available and our own custom-synthesized cationic polymer delivery reagents. These results demonstrate the broad potential of PPAA to serve as a platform reagent for the intracellular delivery of cationic cargo.

Multifunctional Delivery Systems for Peptide Nucleic Acids

“…The endosomolytic polymer is formed by the PEG block that contributes to colloidal stability of the nanoparticles, and by the two D ((dimethylamino)ethyl methacrylate) and B (butyl methacrylate) monomers, which are implied in the pH-responsive function. Since it has been assumed that the efficiency of endosome escape is higher in early endosomal vesicles (pH = 6.8) [ 194 ], various PEG-DB compositions (specifically increasing the percentage of hydrophobic B content from 20% to 70%) have been screened at different pH values in order to evaluate whether a robust membrane disruption at pH 6.8 correlates with the intracellular PNA bioactivity. In this study, they first observed that the stability of the polymer coating increases with the hydrophobicity (% B), which also drives the lipid bilayer membrane insertion.…”

Enhancers in polymeric nonviral gene delivery systems

“…In addition to optimizing nuclear acids condensation and the surface potential of nanoparticles for enhanced uptake, it is also possible to increase the negative charge of the cell membrane through pretreatment to increase cellular uptake. Duvall's group designed an anionic polymer poly(propylacrylic acid) (PPAA) 47 . Pretreatment of cells with PPAA can enhance cell uptake and endosome escape of cationic biomacromolecules and nanostructures (Figure 4).…”

“…Schematic diagram of the mechanism of the anionic polymer PPAA‐mediated cationic peptide uptake and intracellular delivery. Reproduced with permission 47 . Copyright 2019, the Authors…”

pH-Responsive Amphiphilic Carboxylate Polymers: Design and Potential for Endosomal Escape

“…The time plotted indicated the first application for pH-dependent membrane permeabilization, instead of the first reported synthesis of the polymer. (Wang, 2018;Evans et al, 2019). Albeit less renowned, recent studies show their emerging potentials for proteins, genes, and vaccine delivery (Mukalel et al, 2018;Qiu et al, 2018;Evans et al, 2019;Jacobson et al, 2019;Kopytynski et al, 2020).…”