Elucidating the Impact of Endogenous Proteins on Lipid Nanoparticle Organ-Targeting Outcomes

Ribonucleic acid (RNA) biomolecules can be used for the prevention and treatment of various diseases by gene silencing, gene expression, and gene editing approaches. As RNA can be easily degraded by nucleases and does not readily cross the cell membrane to access the cytosol, where it is biologically active, a delivery system is necessary to circumnavigate these obstacles and ensure targeting of the proper cell type(s). Presently, lipid nanoparticles (LNPs) represent the most clinically-advanced system for delivery of multiple classes of RNA, including small interfering RNA (siRNA), messenger RNA (mRNA), and guide RNAs for genome editing. Despite this progress, precise control of delivery to a desired organ to access specific cell type(s) is necessary as RNA remains largely limited to applications involving localized routes of administration, such as vaccination, or disease targets in the liver due to significant hepatic accumulation of LNPs following intravenous administration. This dissertation aims to elucidate the biological interactions that enable extrahepatic RNA delivery by LNPs via systemic injection. The preferential liver delivery of LNPs results from interactions with plasma proteins involved in endogenous cholesterol transport. Building on this foundation, I characterized the targeting mechanism of selective organ targeting (SORT) nanoparticles, an LNP platform for tissue-specific RNA delivery to therapeutically-relevant cells of the liver, spleen, or lungs after intravenous injection. I discovered that the biophysical class of a 5th lipid added to the LNP, termed a SORT molecule, alters the LNP's biodistribution, ionization behavior, and plasma protein interactions. Furthermore, I provide evidence for an endogenous targeting mechanism wherein binding of distinct proteins to the nanoparticle surface facilitates tissue-specific RNA delivery through interactions between surface-bound proteins and cognate receptors highly expressed by cells in the target organ. Further studies on a specific chemical series of SORT molecules within the same biophysical class revealed that a nuanced relationship exists between LNP chemistry, plasma protein interactions, and the tissue-specificity of mRNA delivery. Collectively, these findings lay the foundation for an innovative paradigm - endogenous targeting - wherein the molecular composition of a nanoparticle is rationally engineered to promote binding of specific plasma proteins that yield a desired delivery outcome.

Author dc:creator

• Dilliard, Sean Aaron

Contributors dc:contributor

• Corbin, Ian R.
• Thomas, Philip J.
• Brugarolas, James B.
• Herz, Joachim
• Siegwart, Daniel J.

• Gene Editing
• Liposomes
• Nanoparticles
• Protein Corona
• RNA, Messenger

Language dc:language

en

Identifier

1535537212

OAI identifier oai:identifier

oai:utswmed-ir.tdl.org:2152.5/10697