Why NC-TNP? Limitations of ionizable lipid!

Well, everyone knows! Not only the liver organ restriction of ionizable lipid nanoparticals. The limitations for ionizable lipids in mRNA delivery also include their highly inflammatory and cytotoxic effects due to excess cationic charge density. This complexity leads to inefficient gene transference and cytoplasmic internalization, with the adverse targeting of unintended tissues and susceptibility to extracellular degradation. So, someone one need to work on this! Like this paper. Such as use NC-TNP, noncationic thiourea lipids, it binds and compresses mRNA via hydrogen bonds rather than electrostatic forces. This approach minimizes inflammatory and cytotoxic side effects, enhances gene transfection efficiency, and targets the spleen more effectively, thereby inducing stronger immune responses and avoiding traditional lipid-related issues.

Mild stability differences between NC-TNP and LNP mRNA 

NC-TNP/mRNA demonstrates improved stability compared to LNP/mRNA, as indicated by slightly changed 😄 size distribution and maintained mRNA integrity after long-term storage. Notably, NC-TNP prepared with noncationic thiourea lipids containing a carbon tail of C18 exhibited higher stability than those with carbon tails of C6 or C12. This led to the selection of NC-TNP with a carbon tail of C18 for further studies​​. 

As marked by “slightly changed” which corresponding well with the data (Figure 1 D,E,F,G on top). So, acture stability differences between NC-TNP and LNP/mRNA are minus.

Very striking! the long lasting expression!

In vivo, NC-TNP/mRNA was capable of translating luciferase proteins with significant fluorescence signals for an extended duration, up to 20 days post-injection. This was in contrast to LNP/mRNA, which showed protein expression for a maximum of 3 days. The translational half-life of NC-TNP was about ten times longer than that of LNP, indicating that NC-TNP can protect mRNA from degradation and enhance the duration of gene transfection in vivo. This finding was consistent with in vitro cellular trafficking results​​.

Well, it is a bit hard to understand why NC-TNP mRNA can last for 20 days on mice. The mRNA is realised far slower than LNP/mRNA? Or, the protein is more stable than the LNP/mRNA translated?

Immune response persisted, or even stronger!

NC-TNP was also found to be effective as a vaccine to induce robust immune responses. In immunization tests with mice, NC-TNP/mRNA led to higher percentages of mature dendritic cells (DCs) and specific CD8+ T cells, indicating a stronger immune response compared to LNP/mRNA. The study suggests that NC-TNP could be a promising tool for disease treatment, capable of inducing strong and lasting immune responses​​.

The statment about the immunisation is clear. However, there are spaces for improving flow representative figure.

Criticals:

It is just a bit hard to believe, the NC-TNP is superior on every aspect to LNP (SM-102): stabiblity, in vivo expression, lower immunogencity but higher induces higher immune response…. Well, maybe it is true. We don’t have NC-TNP yet, we are waiting more result to come from other labs. But, we have OVA mRNA expression plasmid! Better quality, and good price!