Strategies for targeted therapeutic RNA delivery using lipid nanoparticles

Abstract

This thesis explores a range of strategies aimed at enhancing RNA delivery beyond the liver through the use of lipid nanoparticles (LNPs). A major focus of the work is on mitigating the rapid clearance of LNPs by the reticuloendothelial system (RES), which is attempted by employing RES blockade strategies aiming to extend LNP circulation time and enhance their accumulation in tumors. Additionally, the study investigates the functionalization of LNP surfaces with targeting ligands, a strategy designed to improve the specificity of RNA delivery to prostate cancer cells in vivo. By engineering LNPs to recognize and bind selectively to cancer cell receptors, this approach aims to maximize therapeutic efficacy while minimizing off-target effects. Another key focus of this thesis is the exploration of alternative administration routes to extend the applicability of LNP-mediated RNA delivery to different disease contexts. Specifically, in this thesis we examine intramyocardial administration of various LNP formulations as a promising strategy for treating heart diseases. By directly injecting LNPs into cardiac tissue, the study evaluates the efficiency of LNP uptake and RNA expression within the heart. In this thesis we evaluate LNP-based delivery systems for both small interfering RNA (siRNA) and messenger RNA (mRNA) in diverse in vivo animal models. This includes a thorough assessment of administration routes, biodistribution, gene silencing or expression efficiency, and the immune responses triggered by these nanoparticles. Special attention is given to the associated inflammation and toxicity profiles of different LNP formulations, providing critical insights into their safety and translational potential. Finally, the research explores the rapidly expanding field of extracellular vesicles as alternative drug delivery systems (DDS) to synthetic lipid-based nanoparticles. Over the past decade, extracellular vesicles have gained significant interest due to their innate biocompatibility, lower immunogenicity, and potential for cell-specific targeting. By comparing these naturally derived vesicles with synthetic LNPs, the study aims to elucidate their respective advantages and limitations, ultimately contributing to the broader effort of optimizing RNA-based therapeutic strategies for a range of medical applications.