Mannosylated Cationic Copolymers for Gene Delivery to Macrophages

Area of Science:

• Biotechnology
• Nanomedicine
• Gene Therapy

Background:

• Macrophages are key targets for gene therapy in cancer and other diseases.
• Developing safe and effective non-viral gene delivery vectors is crucial.
• Cationic diblock copolymers offer potential for targeted delivery.

Purpose of the Study:

• To synthesize and evaluate mannose-decorated polyplexes for targeted gene delivery to macrophages.
• To compare the efficacy and toxicity of different copolymer formulations.
• To assess the potential of these polyplexes as vectors for immune cell-based gene therapy.

Main Methods:

• Synthesis of polyethylene glycol (PEG)-based diblock copolymers (PEG-b-PLL and PEG-b-pAsp(DET)).
• Formation of polyplexes with plasmid DNA (pDNA), decorated with mannose moieties.
• Cross-linking of PEG-b-PLL polyplexes with dithiobis(succinimidyl propionate) (DSP).
• Evaluation of polyplex toxicity using NIH/3T3 fibroblasts and bone marrow-derived macrophages (BMMΦ) or IC-21 cell line.
• Assessment of transfection efficiency in macrophages.

Main Results:

• Mannose-decorated polyplexes showed significantly higher transfection efficiency in macrophages (≈8-fold for PEG-b-PLL, ≈500-fold for PEG-b-pAsp(DET)) compared to non-targeted polyplexes.
• Cross-linking PEG-b-PLL polyplexes reduced toxicity but had a moderate impact on transfection enhancement.
• PEG-b-pAsp(DET) based polyplexes exhibited low toxicity and superior transfection efficiency.
• The Man-PEG-b-pAsp(DET)/pDNA polyplex demonstrated exceptional targeting and gene transfer capabilities.

Conclusions:

• Mannose-decorated PEG-b-pAsp(DET) polyplexes are highly effective and low-toxicity non-viral vectors for gene delivery to macrophages.
• These findings suggest significant potential for mannose-modified polyplexes in immune cell-targeted gene therapy applications.
• The study highlights the advantage of specific copolymer design for optimizing gene delivery systems.