Cholic acid-mediated targeting of mRNA-LNPs improve the mRNA delivery to Caco-2 cells

Oral administration of mRNA-encapsulated lipid nanoparticles (mRNA-LNPs) is challenging due to various factors, including the low efficiency of mRNA-LNP uptake by small intestinal epithelial cells due to the low levels of apolipoprotein-E in gastrointestinal fluid. Therefore, in this study, we aimed to improve mRNA-LNP uptake by intestinal cells by modifying the surface of mRNA-LNPs with bile acids. Bile acids are recognized by bile acid transporters in the small intestine. We synthesized a polyethylene glycol (PEG)-lipid bound to cholic acid, a type of bile acid, and prepared cholic acid-modified mRNA-LNPs (Cholic-PEG-LNPs) using an ethanol dilution method with a microfluidic device. Uptake of Cholic-PEG-LNPs by differentiated Caco-2 cells was higher than that of unmodified PEG-LNPs. Moreover, protein expression induced by Cholic-PEG-LNPs was higher than that induced by unmodified PEG-LNPs in differentiated Caco-2 cells, and no difference was observed in bile acid transporter-negative MCF-7 cells. These results suggest that the cholic acid modification of mRNA-LNPs enhances bile acid transporter-mediated cellular uptake and protein expression. Our strategy can be used to enhance the functionality of oral mRNA-LNPs.