Effective RNA Delivery with Aggregation-Induced Lipid Backfolding.

Area of Science:

• Biochemistry and Molecular Biology
• Materials Science
• Drug Delivery Systems

Background:

• Lipid nanoparticles (LNPs) are crucial for RNA delivery, but efficient endosomal escape remains a challenge.
• Current strategies for LNP formulation rely on high-throughput screening without clear design principles for ionizable lipids.
• Developing rational design guidelines for ionizable lipids is essential for advancing RNA-based therapies.

Purpose of the Study:

• To propose a lipid structure-based strategy for guiding LNP formulation.
• To investigate the role of asymmetric hydrocarbon tails in enhancing LNP endosomal escape.
• To establish guidelines for designing ionizable lipids for improved RNA delivery.

Main Methods:

• All-atom molecular dynamics simulations to study lipid-membrane interactions.
• Design and formulation of LNPs with asymmetric-tailed lipids (L-Ada).
• Membrane fusion experiments to validate simulation findings.
• Development of a thermodynamic model for LNP design.

Main Results:

• Asymmetric lipids, like L-Ada, induce lipid back-folding and membrane packing defects, facilitating membrane fusion.
• A combined formulation of 20% L-Ada and 80% symmetric lipid L-Ste balances membrane defects and rigidity.
• Optimized LNP formulation demonstrated enhanced membrane fusion capabilities.
• A thermodynamic model provides specific design guidelines for ionizable lipids.

Conclusions:

• LNPs incorporating asymmetrically tailed lipids show enhanced membrane fusion and endosomal escape.
• The proposed lipid structure-based strategy offers a rational approach to LNP formulation.
• This work provides a foundation for optimizing future LNP formulations for RNA therapies.