Messenger RNA (mRNA) has flourished as a strategy to generate transient gene expression in immune cells to mitigate the disadvantages associated with viral vectors, including CAR therapy. Lipid nanoparticles for mRNA delivery (LNP) have been used in the pharmaceutical industry as vectors for the delivery of a variety of therapeutics. BOC Sciences' platform offers fully validated mRNA delivery or mRNA LNP delivery systems to induce functional protein expression and to investigate the potential of mRNA and LNP-based gene therapy.
In addition to negatively charged mRNA, Lipid nanoparticles (LNP) loaded with mRNA have four other components: ionizable cationic phospholipids, neutral auxiliary phospholipids, cholesterol, and polyethylene glycol modification PEGylated lipid)
|Cationic phospholipids (ionizable)||About 50%|
|Auxiliary phospholipids (neutral)||About 10%|
|PEGylated phospholipids||About 1.5%|
Table. 1 Proportion of LNP components
The role of excipients in lipid nanoparticles is similar to that of such excipients in liposomes:
Ionizable cationic phospholipid is a key determinant of mRNA delivery and transfection efficiency. The cationic phospholipid needs to be non-ionized under physiological conditions (pH=7.4) and ionized under acidic conditions (≤5.0).
Before entry into the cell, cationic lipids can achieve electrostatic complexation with negatively charged mRNA molecules, forming a complex that improves the stability of the mRNA molecules. When mRNA/LNP reaches the cell membrane, the cationic phospholipid triggers membrane fusion with the negatively charged cell membrane, which destabilizes and facilitates the delivery of mRNA molecules. After internalization into the cell, as the lysosomes containing a variety of hydrolytic enzymes break down the exogenous and exogenous macromolecules, the pH drops to create an acidic environment, which protonates the ionizable lipids and disrupts the bilayer structure of the LNP, releasing the mRNA, which binds to the ribosomes responsible for protein production in accordance with the 'central law' and is translated into viral proteins, i.e. antibodies, which neutralize the virus.
Fig. 1 Schematic representation of the different types of lipid-base nanovectors (Guevara ML,2020)