Summary
This study investigates the impact of different lipid compositions and RNA cargos of lipid nanoparticles (LNPs) on gene knockdown and expression efficiency for lung delivery. Four LNP formulations were prepared via microfluidics for siRNA and mRNA delivery, varying in helper lipids (DSPC or DOPE) and PEG-lipids (DMG-PEG or DMPE-PEG). The resulting LNPs were tested regarding their physicochemical properties, cellular uptake, and performance in vitro in both submerged and air-liquid interface (ALI) cell culture systems. The ALI model more accurately reflects lung physiology and enables the evaluation of the ability of LNP formulations to overcome the mucus barrier present in the lungs [1]. The results indicate similar physicochemical properties across different LNP formulations. Certain formulations of siRNA LNPs showed superior performance in gene silencing, attributed to the helper lipid DOPE. In contrast, DSPC-containing LNPs exhibited increased cellular uptake. The study suggests that the enhanced siRNA release into the cytosol due to DOPE´s conical structure promoting endosomal escape and probably lower RNA binding efficiency enhance gene silencing efficiency [2]. These effects were not observed in mRNA formulations or in ALI cultured cells, where LNP formulations performed similarly. The structural differences between mRNA and siRNA may explain this discrepancy. In ALI cell cultures, the mucus layer presents an important hurdle for cellular uptake, yet LNPs effectively overcame this barrier, demonstrating efficient gene knockdown. These findings showcase the potential of LNPs as a promising tool for targeted gene regulation in lung-related diseases.