Nucleic Acid-Loaded Lipid Nanoparticle Interactions with Model Endosomal Membranes.

Area of Science:

• Biochemistry
• Nanotechnology
• Drug Delivery

Background:

• Lipid nanoparticles (LNPs) are crucial for delivering RNA-based therapeutics.
• The precise mechanism of LNP interaction with endosomal membranes is not fully understood.
• Understanding these interactions is key to optimizing LNP-based drug delivery systems.

Purpose of the Study:

• To investigate the interaction of nucleic acid-loaded LNPs with model early and late endosomal membranes.
• To elucidate the influence of subphase pH, endosomal stage, and nucleic acid cargo on LNP-membrane interactions.
• To provide novel insights into LNP behavior within the endosomal pathway for improved therapeutic design.

Main Methods:

• Utilized different reflectometry techniques to study LNP interactions with model endosomal membranes.
• Examined LNP behavior across a range of pH conditions (e.g., 6.5, 5.5, and higher).
• Compared interactions with model membranes representing early and late endosomes, and with different nucleic acid cargos (mRNA vs. Poly(A)).

Main Results:

• LNP lipid insertion into model membranes peaked at pH 6.5 and 5.5; higher pH led to suppressed insertion and intact LNP binding.
• The stage of the endosome (early vs. late) had minimal impact on the extent of LNP interaction, irrespective of pH.
• LNPs carrying mRNA demonstrated greater nucleic acid delivery compared to those with Poly(A), indicating cargo-dependent interaction tuning.

Conclusions:

• Endosomal pH is a critical factor influencing LNP fusion and lipid insertion during the endosomal pathway.
• Late endosome characteristics like fluidity and anionic nature do not significantly alter LNP interaction extent.
• The nature of the nucleic acid cargo can be modulated to tune LNP interaction and delivery efficiency, vital for designing advanced LNP therapeutics.