N-Acetylgalactosamine Block-co-Polycations Form Stable Polyplexes with Plasmids and Promote Liver-Targeted Delivery

Abstract

The liver is an ideal target for nucleic acid therapeutic applications (i.e., siRNA, gene therapy, and genome editing) due to its ability to secrete proteins into the blood. In this work, we present the first synthesis of a novel monomer derived from N-acetyl-d-galactosamine (GalNAc) and its polymerization as a facile route to create multivalent delivery vehicles with exceptional targeting efficiency to asialoglycoprotein receptors (ASGPRs) on liver hepatocytes. A series of cationic diblock GalNAc glycopolymers composed of a GalNAc-derived block of fixed length (n = 62) and cationic 2-aminoethylmethacrylamide (AEMA) blocks of varying lengths (n = 19, 33, and 80) have been synthesized and characterized. In addition, nontargeted control polymers consisting of either glucose or polyethylene glycol-derived neutral blocks with an AEMA cationic block were also created and examined. All polymeric vehicles were able to bind and encapsulate plasmids (pDNA) into polymer-pDNA complexes (polyplexes). The GalNAc-derived polyplexes were colloidally stable and maintained their size over a period of 4 h in reduced-serum cell culture media. The GalNAc-derived homopolymer effectively inhibited the uptake of Cy5-labeled asialofetuin (a natural ligand of ASGPRs) by cultured hepatocyte (HepG2) cells at lower concentrations (IC50 = 20 nM) than monomeric GalNAc (IC50 = 1 mM) and asialofetuin (IC50 = 1 μM), suggesting highly enhanced ASGPR binding due to multivalency. These polymers also showed cell type-specific gene expression in cultured cells, with higher protein expression in ASGPR-presenting HepG2 than HeLa cells, which lack the receptor. Biodistribution studies in mice show higher accumulation of pDNA and GalNAc-derived polymers in the liver compared with the glucose-derived nontargeted control. This study demonstrates the first facile synthesis of a multivalent GalNAc-derived block copolymer architecture that promotes enhanced delivery to liver and offers insights to improve targeted nanomedicines for a variety of applications.

Oligo(serine ester) Charge-Altering Releasable Transporters: Organocatalytic Ring-Opening Polymerization and their Use for in Vitro and in Vivo mRNA Delivery

“…8,9 These restrictions have stimulated interest in nonviral vectors, typically lipid nanoparticles and cationic polymers that form electrostatic complexes with polyanionic nucleic acids. 7,[10][11][12][13][14][15][16] Despite advances in nonviral vectors, challenges with accessibility, formulation, efficacy, tolerability, and targetability have prompted the search for improved delivery systems, with a particular emphasis on degradable vectors. [17][18][19][20][21][22] We recently reported a new class of synthetic biodegradable gene delivery materials, dubbed charge-altering releasable transporters (CARTs) (e.g., 1).…”

Optimization of film over nanosphere substrate fabrication for SERS sensing of the allergen soybean agglutinin

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Highly efficient reversible addition-fragmentation chain-transfer polymerization in ethanol/water via flow chemistry

“…Controlled radical polymerization (CRP) provides a method to produce polymers with well‐controlled properties and hence broad applications in drug delivery, self‐healing materials, energy storage, optoelectronic devices, etc . Atom transfer radical polymerization, reversible addition–fragmentation chain‐transfer (RAFT) polymerization and nitroxide‐mediated radical polymerization are three of the main CRP strategies.…”