High-density lipoprotein-like nanoparticles with cationic cholesterol derivatives for siRNA delivery

A new approach to siRNA delivery using high-density lipoprotein-like nanoparticles (HDL NPs) was investigated, incorporating oligoamine and cholesterol-derived cationic lipids (CLs) to associate siRNA with the carrier. Newly designed or commercially available compounds, including GL67 and 3-$\beta$-[N-(N′,N′-dimethylaminoethane)-carbamoyl]cholesterol (DC-Cholesterol), were tested for siRNA binding, cytotoxicity, and siRNA cellular uptake. GL67 emerged as the most promising CL for siRNA delivery via HDL NPs. While it contributed to substantial siRNA uptake and cytosolic delivery in HepG2 cells, gene silencing remained limited, indicating a need for further optimization. Despite this, the study highlights the potential of positively charged cholesterol derivatives for siRNA delivery using HDL NPs. An analysis of the relationship between CL head group structure and HDL NPs' siRNA binding efficiency and cytotoxicity showed that factors such as oligoamine molecule conjugation site, linker type, amine group ethylation, and alkyl chain length between amine groups are crucial for optimizing CL design. Furthermore, the phospholipid environment surrounding CLs significantly influences HDL NPs' performance, particularly in siRNA cellular uptake. The study also revealed that intracellular siRNA trafficking varies by cell type, emphasizing the importance of customizing HDL NP formulations for specific cells. These insights are important for designing more effective HDL NPs for siRNA therapeutic delivery.