Engineering Lipid Nanoparticles (LNPs) to Target and Deliver mRNA to the Lungs

Abstract

Targeted nanoparticles hold strong potential in treating diseases which cannot be cured currently. The pharmacokinetic and pharmacodynamic profile of active pharmaceutical ingredients such us small molecules, peptides, proteins, and nucleic acids can be improved by utilizing nanoparticles as drug delivery systems. The first generation of nanoparticles utilizes the enhanced permeability and retention (EPR) effect to passively target the tumor microenvironment. Doxil and DaunoXome are two examples of the first generation of nanoparticulate medicines approved by FDA. The second-generation nanoparticles are nanoparticles functionalized with specific ligands to actively target organs/tissues of interest. In this project, targeted lipid nanoparticles (LNPs) that mediate the specific delivery of mRNA to the lungs via a caveolae targeted pathway were developed. Caveolae are small invaginations on plasma membrane that make up more than 70% of the total endothelial membrane in lung blood capillaries making it an attractive pathway for mRNA delivery. The specific delivery of mRNA to lungs can be useful in the treatment of a wide range of pulmonary diseases including pulmonary genetic disorders and lung cancer. To formulate caveolae targeted LNPs, antibodies targeting the caveolae invaginations were used to functionalize the LNPs. In vivo studies were performed in mice to understand the biodistribution and mRNA translational efficacy of the novel caveolae targeted LNPs. We successfully showed that caveolae targeted LNPs localized and delivered mRNA to the lungs and the delivered mRNA was expressed by lung cells. Non-targeting LNPs accumulated in the liver and spleen which is consistent with previous published studies. Additionally, we also investigated how other LNP critical attributes such us size and PEG density impact the biodistribution of LNPs in mice. Increasing the LNP size to ~160nm lead to a significant increase in the expression of mRNA in the lungs for caveolae targeted LNPs, while a significant reduction on the mRNA expression was observed in the liver. Fine tuning the chemical composition of targeted LNPs has also led to a significant increase in the mRNA expression in the lungs. Overall, we were able to develop a unique and novel approach of mRNA delivery to the lung using targeted LNPs.