Optimizing Peptide Ionizable Lipids Enables Efficient and Low-Toxicity mRNA Delivery for In Vivo Prime Editing and...

Area of Science:

• Biotechnology
• Molecular Biology
• Drug Delivery Systems

Background:

• mRNA lipid nanoparticles (LNPs) are crucial for delivering genetic material but can pose safety risks.
• Developing safe and effective mRNA-LNPs requires understanding the relationship between lipid structure and function.

Purpose of the Study:

• To establish a structure-activity relationship (SAR) framework for peptide ionizable lipids (PILs) to guide the rational design of mRNA-LNPs.
• To identify novel PILs that balance high delivery efficiency with minimized toxicity.

Main Methods:

• Systematic optimization of PIL structure, including building blocks, side-chain length, and hydrophobic tails.
• Synthesis and evaluation of Dab4-derived PILs with varying tail chemistries (alkyl, ester, hydroxyl).
• In vivo assessment of LNP performance, including hepatic delivery efficiency, biosafety, and therapeutic efficacy in a Hereditary Tyrosinemia Type 1 model.

Main Results:

• A lead compound, Dab4, showed minimized hepatotoxicity and superior delivery performance.
• Tail chemistry influenced organ tropism; B12-a13Dab4 (alkyl tail) demonstrated optimal liver delivery.
• B12-a13Dab4 LNP outperformed the FDA-approved SM-102 formulation in hepatic delivery and biosafety.
• B12-a13Dab4 LNP successfully facilitated in vivo prime editing and demonstrated therapeutic effects in an HT-1 model.

Conclusions:

• The established SAR framework enables the rational design of safe and effective mRNA-LNPs.
• The novel B12-a13Dab4 LNP offers a promising platform for gene editing and protein replacement therapies.
• This work provides a versatile approach to advance mRNA-based therapeutics with improved safety and efficacy profiles.