RNA Nanotherapeutics with Fibrosis Overexpression and Retention (FORT) for NASH Treatment

Abstract

Fibrotic diseases, like non-alcoholic steatohepatitis (NASH), pose challenges for targeted delivery and retention of therapeutic proteins due to increased extracellular matrix (ECM) deposition. Here we present a new approach to treat fibrotic diseases, termed “Fibrosis overexpression and retention (FORT)”. In this two-step strategy, we design 1) a retinoid derivative lipid nanoparticle (LNP) to enable specific mRNA overexpression in hepatic stellate cells, and 2) mRNA modifications which facilitate anchoring of therapeutic proteins in the fibrotic ECM. LNPs containing carboxyl retinoid derivatives, as opposed to alcohol or ester retinoid derivatives, effectively delivered mRNA, resulting in more than 10- fold enhancement of protein expression within the fibrotic liver. The carboxyl retinoid rearrangement on the LNP surface improved protein binding, sprouting, and membrane fusion. Therapeutic relaxin fusion proteins were then engineered with an endogenous collagen-binding domain. These fusion proteins exhibited increased retention in fibrotic lesions and reduced systemic side effects. In vivo, fibrosis-targeting LNPs encoding for mRNA fusion proteins demonstrated superior therapeutic efficacy in three clinically relevant NASH mouse models. This approach holds promise in chronic fibrotic diseases that are unsuited for direct injections of recombinant proteins.