Boosting mRNA Therapeutics: pHLIP Enhances Endosomal Escape and Gene Expression in Lipid Nanoparticle.

Messenger RNA (mRNA) has emerged as a transformative technology for combating viral pandemics and malignancies, with lipid nanoparticle (LNP)-based mRNA vaccines playing a pivotal role in the COVID-19 pandemic. However, current LNP face challenges such as low endosomal escape efficiency (<5%), leading to cargo waste and increased costs. To address this, pHLIP-incorporated LNP (mRNA@LNP-pHLIP), leveraging the pH-dependent membrane-insertion properties of pHLIP is developed to enhance endosomal escape. pHLIP undergoes a conformational change in acidic environments, enabling it to insert into endosomal membranes and promote the release of mRNA into the cytosol. In vitro studies demonstrate a three to fivefold increase in mRNA expression across multiple cell lines, while in vivo experiments show sustained and higher protein expression in mice. Applied to a monkeypox vaccine encoding A35R and M1R antigens, mRNA@LNP-pHLIP elicited stronger immune responses, highlighting its potential for next-generation mRNA therapeutics and vaccines.