Splenic gene delivery system using self-assembling nano-complex with phosphatidylserine analog.

Area of Science:

• Biomedical Engineering
• Gene Therapy
• Drug Delivery Systems

Background:

• Phosphatidylserine recognition on erythrocytes mediates macrophage uptake.
• Targeting spleen macrophages offers a novel route for splenic gene delivery.
• 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) was selected as a phosphatidylserine analogue.

Purpose of the Study:

• To prepare and evaluate a stable plasmid DNA (pDNA) ternary complex using DOPS and polyethyleneimine (PEI) for splenic gene delivery.
• To assess the efficacy and safety of the pDNA/PEI/DOPS complex compared to pDNA/PEI.
• To investigate the in vitro and in vivo performance of the DOPS-modified complex.

Main Methods:

• Preparation of a stable pDNA ternary complex with DOPS and PEI.
• Evaluation of complex charge (ζ-potential), cytotoxicity, and agglutination.
• In vitro transgene efficacy assessment using fluorescence microscopy.
• In vivo safety and biodistribution studies in mice following intravenous injection.

Main Results:

• The pDNA/PEI complex exhibited positive charge, high efficacy, but also cytotoxicity and agglutination.
• The addition of DOPS resulted in a negatively charged pDNA/PEI/DOPS complex.
• Despite negative charge, the pDNA/PEI/DOPS complex showed significant in vitro transgene efficacy and cellular internalization.
• All mice survived pDNA/PEI/DOPS complex injection, whereas pDNA/PEI caused mortality, indicating improved safety.
• High, selective gene expression in the spleen was observed after intravenous administration of the pDNA/PEI/DOPS complex.

Conclusions:

• The pDNA/PEI/DOPS ternary complex is a safe and effective system for splenic gene delivery.
• DOPS modification significantly enhances the safety profile of pDNA/PEI complexes.
• The complex demonstrates potential for targeting gene delivery to abundant immune cells in the spleen.