Star-shaped copolymer grafted PEI and REDV as a gene carrier to improve migration of endothelial cells.

In this work, a biodegradable star-shaped copolymer poly(lactide-co-3(S)-methyl-morpholine-2,5-dione)6 (Star-(PLMD)6) was synthesized via ring-opening polymerization (ROP), and subsequently a gene carrier Star-PLMD-g-PEI-g-PEG-CREDVW was prepared by grafting polyethyleneimine (PEI), polyethylene glycol (PEG) and targeting peptide REDV onto Star-(PLMD)6. This gene carrier could form stable micelles to condense pEGFP-ZNF580 through electrostatic interaction. The resulting complexes were biocompatible and showed high efficiency in gene delivery. In addition, these complexes exhibited high selectivity for endothelial cells (ECs), high transfection efficiency and enhanced migration of ECs. The protein level of ZNF580 expression was significantly high (up to 85%), while the control group was only 51%. This combination of degradability, targeting ligand and star-structure strategy exhibits a significant advantage in transfection efficiency and migration of ECs.

CAGW Peptide- and PEG-Modified Gene Carrier for Selective Gene Delivery and Promotion of Angiogenesis in HUVECs in Vivo.

Gene therapy is a promising strategy for angiogenesis, but developing gene carriers with low cytotoxicity and high gene delivery efficiency in vivo is a key issue. In the present study, we synthesized the CAGW peptide- and poly(ethylene glycol) (PEG)-modified amphiphilic copolymers. CAGW peptide serves as a targeting ligand for endothelial cells (ECs). Different amounts of CAGW peptide were effectively conjugated to the amphiphilic copolymer via heterofunctional poly(ethylene glycol). These CAG- and PEG-modified copolymers could form nanoparticles (NPs) by self-assembly method and were used as gene carriers for the pEGFP-ZNF580 (pZNF580) plasmid. CAGW and PEG modification coordinately improved the hemocompatibility and cytocompatibility of NPs. The results of cellular uptake showed significantly enhanced internalization efficiency of pZNF580 after CAGW modification. Gene expression at mRNA and protein levels demonstrated that EC-targeted NPs possessed high gene delivery efficiency, especially the NPs with higher content of CAGW peptide (1.16 wt %). Furthermore, in vitro and in vivo vascularization assays also showed outstanding vascularization ability of human umbilical vein endothelial cells treated by the NP/pZNF580 complexes. This study demonstrates that the CAGW peptide-modified NP is a promising candidate for gene therapy in angiogenesis.

CAGW Peptide Modified Biodegradable Cationic Copolymer for Effective Gene Delivery.

In recent years, gene therapy has become a promising technology to enhance endothelialization of artificial vascular grafts. The ideal gene therapy requires a gene carrier with low cytotoxicity and high transfection efficiency. In this paper, we prepared a biodegradable cationic copolymer poly(d,l-lactide-co-glycolide)-graft-PEI (PLGA-g-PEI), grafted Cys-Ala-Gly-Trp (CAGW) peptide onto this copolymer via the thiol-ene Click-reaction, and then prepared micelles by a self-assembly method. pEGFP-ZNF580 plasmids (pDNA) were condensed by these micelles via electrostatic interaction to form gene complexes. The CAGW peptide enables these gene complexes with special recognition for endothelial cells, which could enhance their transfection. As a gene carrier system, the PLGA-g-PEI-g-CAGW/pDNA gene complexes were evaluated and the results showed that they had suitable diameter and zeta potential for cellular uptake, and exhibited low cytotoxicity and high transfection efficiency for EA.hy926 cells.

Bioreducible, hydrolytically degradable and targeting polymers for gene delivery.

Recently, synthetic gene carriers have been intensively developed owing to their promising application in gene therapy and considered as a suitable alternative to viral vectors because of several benefits. But cationic polymers still face some problems like low transfection efficiency, cytotoxicity, and poor cell recognition and internalization. The emerging engineered and smart polymers can respond to some changes in the biological environment like pH change, ionic strength change and redox potential, which is beneficial for cellular uptake. Redox-sensitive disulfide based and hydrolytically degradable cationic polymers serve as gene carriers with excellent transfection efficiency and good biocompatibility owing to degradation in the cytoplasm. Additionally, biodegradable polymeric micelles with cell-targeting function are recently emerging gene carriers, especially for the transfection of endothelial cells. In this review, some strategies for gene carriers based on these bioreducible and hydrolytically degradable polymers will be illustrated.