An Ionizable Cationic Lipid for Intracellular RNA Delivery

Objective: Ionizable lipids are a key component of the lipid nanoparticle platform for RNA therapy. They ensure efficient assembly of a lipid-nucleic acid complex, protect it against premature degradation, and after endocytosis, promote the release of RNA into the cytoplasm for further processing. Despite the multiple proposed ionizable cationic lipids, the search for molecules to improve the efficacy and safety profile of lipid nanoparticles (LNPs) for RNA delivery continues. Methods: The paper describes the synthesis of a new ionizable cationic lipid that is a diglyceride derivative of tertiary alkylamine, [5-[1,2-di(decanoyloxy)propane-3-yloxy]pentyl-(4-hydroxybutyl)-amino]pentoxy]-2-decanoyloxypropyl]decanoate (An-1). Lipid An-1, along with the common so-called helper lipids, was used to formulate LNPs with mRNA of the green fluorescent protein. The functional activity of the LNPs with mRNA-GFP was tested in a culture of human embryonic kidney cells HEK293T. Results and Discussion: The synthesis of An-1 is characterized by simplicity and cost-effectiveness of reagents. Comparative experiments with the lipid ALC-0315 have shown that An-1 lipid forms LNPs similar in size and incorporation efficiency of the model mRNA. The LNPs containing mRNA-GFP, formulated with An-1 lipid, transfected cells more efficiently than those formulated with ALC-0315 lipid. Conclusions: A new ionizable cationic lipid was synthesized. Its molecule does not contain branched alkyl chains whose metabolism is difficult. This may be the reason for effective transfection of RNA-LNPs comprising An-1. It is assumed that the new ionizable lipid can be used in the production of mRNA vaccines.