Mannose-Conjugated Cholesterol Containing Lipid Nanoparticles for Active Targeted mRNA Delivery to Liver Sinusoidal Endothelial and Kupffer Cells

Abstract

Lipid nanoparticle (LNP) delivery of mRNA to specific cell types is a necessary task for the development of safe and effective medicines. LNP delivery to the liver is largely driven by the binding of serum ApoE to the LNP surface, followed by subsequent uptake in LDL receptor (LDL-R)-expressing hepatocytes, thereby reducing their utility in nonhepatocyte liver diseases. Herein, we developed an active targeting strategy to overcome this limitation by incorporating mannose-conjugated cholesterol into LNPs. Since cholesterol comprises about half of all molecules in LNPs, we reasoned that it could serve as a scaffold for active targeting. Mannosylated LNPs enhance uptake into liver sinusoidal endothelial cells (LSECs) and Kupffer cells over hepatocytes following intravenous administration in mice. This process correlated with the expression of mannose receptors (CD206) in LSECs and Kupffer cells, where significantly greater LNP uptake and functional mRNA delivery occurred in CD206⁺ cells. Higher activity and selectivity could be endowed by reducing the hydrophobic acyl chain length in poly(ethylene glycol) (PEG) lipids to induce faster PEG shedding in systemic circulation and increase LNP surface-accessible mannose, thereby increasing binding interactions with mannose receptors on CD206⁺ cells and subsequent LNP uptake. The results establish that cholesterol can be employed as a ligand carrier in LNPs for enriching mRNA delivery to specific cells in vivo. We anticipate that this general strategy of cholesterol modification can be extended to other ligands and cell types in the future.