Synthesis of Electroneutralized Amphiphilic Copolymers with Peptide Dendrons for Intramuscular Gene Delivery

Abstract

Intramuscular gene delivery materials are of great importance in plasmid-based gene therapy system, but there is limited information so far on how to design and synthesize them. A previous study showed that the peptide dendron-based triblock copolymer with its components arranged in a reversed biomembrane architecture could significantly increase intramuscular gene delivery and expression. Herein, we wonder whether copolymers with biomembrane-mimicking arrangement may have similar function on intramuscular gene delivery. Meanwhile, it is of great significance to uncover the influence of electric charge and molecular structure on the function of the copolymers. To address the issues, amphiphilic triblock copolymers arranged in hydrophilic-hydrophobic-hydrophilic structure were constructed despite the paradoxical characteristics and difficulties in synthesizing such hydrophilic but electroneutral molecules. The as-prepared two copolymers, dendronG2(l-lysine-OH)-poly propylene glycol2k(PPG2k)-dendronG2(l-lysine-OH) (rL2PL2) and dendronG3(l-lysine-OH)-PPG2k-dendronG3(l-lysine-OH) (rL3PL3), were in similar structure but had different hydrophilic components and surface charges, thus leading to different capabilities in gene delivery and expression in skeletal muscle. rL2PL2 was more efficient than Pluronic L64 and rL3PL3 when mediating luciferase, β-galactosidase, and fluorescent protein expressions. Furthermore, rL2PL2-mediated growth-hormone-releasing hormone expression could significantly induce mouse body weight increase in the first 21 days after injection. In addition, both rL2PL2 and rL3PL3 showed good in vivo biosafety in local and systemic administration. Altogether, rL2PL2-mediated gene expression in skeletal muscle exhibited applicable potential for gene therapy. The study revealed that the molecular structure and electric charge were critical factors governing the function of the copolymers for intramuscular gene delivery. It can be concluded that, combined with the previous study, both structural arrangements either reverse or similar to the biomembrane are effective in designing such copolymers. It also provides an innovative way in designing and synthesizing new electroneutralized triblock copolymers, which could be used safely and efficiently for intramuscular gene delivery.

Synthesis and Characterization of Phosphorus- and Carborane-Containing Polyoxanorbornene Block Copolymers

“…Nanostructures derived by the self-assembly of functional block copolymer is one feasible approach for the preparation of remote-switchable materials at the nanometer length scale [2,3,4,5]. In the last decades amphiphilic block copolymers have attracted a lot of attention because of their unique possibility for self-organization forming micelles or vesicles in selective solvents based on the solubility of their hydrophobic and hydrophilic block segments [6,7,8,9]. Many applications arose from these materials, e.g., in lithography, drug delivery, magnetic nanoparticle stabilization, and, especially, separation technologies with a variety of potential applications [4,6,7,8,9,10,11,12,13,14,15].…”

The Progress of Non-Viral Materials and Methods for Gene Delivery to Skeletal Muscle

“…Grandinetti et al showed that the polymer could directly participate in the nuclear localization of DNA through its membrane destruction characteristics, which may also be the reason for its cytotoxicity [61]. Therefore, it seems to be a better choice to use neutral block polymers since they are more effective than cationic polymers in skeletal muscle gene delivery [14,18,19,62].…”

“…It can also be concluded that if a suitable therapeutic gene is used here instead of mGH, a therapeutic effect may be acquired. In 2016, our research group developed dendronG2(L-lysine-OH)-poly propylene gly-col2k(PPG2k)-dendronG2(L-lysine-OH) (rL2PL2, Figure 6, Table 1) and dendronG3(L-lysine-OH)-PPG2k-dendronG3(L-lysine-OH) (rL3PL3, Figure 6, Table 1) [19] based on previous work [18]. The hydrophilicity and hydrophobicity of rL2PL2 and rL3PL3 are opposite to that of LPL, and structurally similar to that of cell membrane phospholipid bilayer.…”

The Interaction Mechanism of Intramuscular Gene Delivery Materials with Cell Membranes

“…In our previous studies, Pluronic L64 was shown to be one of the most efficient and stable materials for pDNA delivery to skeletal muscles [2], and higher gene delivery efficiency was acquired when Pluronic L64 was combined with a low-voltage electric field [18,19], and was even high enough for therapeutic trials on tumors and diabetes [20,21]. Further, inspired by the similarity of amphiphilic structure between Pluronic L64 and cell membranes, amphiphilic triblock copolymers of LPL [22], rL 2 PL 2 , and rL 3 PL 3 were designed and synthesized [23]. The results showed that LPL and rL 2 PL 2 had better performance than Pluronic L64, evident from intramuscular gene delivery/expression efficiency and biocompatibility.…”