Polish researchers develop new mRNA modification

The group led by Professor Jacek Jemielity from the Centre of New Technologies of the University of Warsaw (CeNT) and Dr. Joanna Kowalska from the Faculty of Physics of the University of Warsaw, in collaboration with a team from the Medical University of Warsaw and the UW spin-off company ExploRNA Therapeutics, has developed a completely new mRNA modification, which - according to its creators - 'may be a breakthrough for modern medicine'.

The discovery will enable further development of  modern targeted therapies based on mRNA technology, including the treatment of rare diseases and the design of anticancer vaccines.

The research results were published in and recently made the cover of the Journal of the American Chemical Society and.

'Thanks to this technology, the world of medicine can think about much broader applications of mRNA,’ says Professor Jemielity. 'We are no longer just talking about the production of anti-Covid vaccines, which seem to be the simplest application of mRNA technology. Such an efficiently translated mRNA molecule can be used to design new anticancer therapies, and in the treatment of various genetic and rare diseases.’

The researchers were looking for a modification of the mRNA molecule that would allow them to obtain as much therapeutic protein as possible with the lowest possible mRNA dose. They proposed a modification of the 5' end of mRNA, which is the extreme fragment of the RNA strand. This change concerns a position that quite often undergoes natural modifications on its own, and involves methylation of adenosine at the N6 position.

The authors explain that it is a posttranscriptional modification because it occurs in cells after mRNA biosynthesis. It is reversible and the body's cells have an enzyme that can remove it (FTO). The function of this natural modification has not yet been explained, but research indicates that its presence is associated with greater mRNA productivity.

The scientists have now replaced the methyl group with a much larger benzyl group. It turns out that it perfectly imitates the natural modification in terms of mRNA properties, but it is not removed by the FTO enzyme. Thanks to this, synthetic mRNA has a much higher productivity, which the FTO enzyme cannot reverse.

In practice, the protein created based on such modified mRNA is produced in much larger quantities.

The researchers called their modification AvantCap (the full name is m6Am-cap–m7GpppBn6AmpG).

'The change we have introduced involves attaching benzyl at a specific point at one of the ends of the mRNA, the so-called cap. Benzyl is attached at a specific site where natural enzymes modify mRNA by adding a methyl group to it after the mRNA has been synthesized. These natural mRNA modifications are reversible and can be removed. Inspired by biology, we decided to modify the mRNA in this position permanently and investigate how it would affect the properties of mRNA,’ says Dr. Marcin Warmiński, co-author of the publication in the Journal of the American Chemical Society.

The research has shown that in some systems, the mRNA molecule with the AvantCap modification is up to six times more productive than without it. This means that, for example, in the case of mRNA COVID-19 vaccines, the new technology could make it possible to produce six times more therapeutic protein than is currently the case. Thanks to this, a stronger therapeutic effect could be achieved in the body with a much lower dose of the preparation.

The authors of the solution add that in certain specific conditions this difference can be even greater - even 100-fold. However, the mechanism by which such efficient protein production can be achieved thanks to the introduced modification is not yet fully explained.

'This is a very interesting phenomenon, but not yet fully explained,' says Dr. Joanna Kowalska. 'We know that certain natural modifications that occur after mRNA transcription in cells give the molecules a higher translation priority. Such molecules are decoded more efficiently under certain conditions, leading to increased production of certain types of proteins. Our modification appears to produce this result - the molecules gain priority in the protein production queue.

'Perhaps mRNA becomes resistant to the action of some enzyme that suppresses its extraordinary biological activity, but further research is required to verify this. The most important thing is that as a result of the modification, we have an mRNA molecule with very interesting therapeutic properties,’ she adds.

Importantly for the pharmaceutical community, the observed properties of mRNA modified with AvantCap are stronger after administration to living organisms (mice) than in cell lines grown in vitro. The researchers have also proven that mRNA encoding a protein characteristic of cancer (called an antigen) administered to mice suffering from this cancer results in significant inhibition of tumour development. However, confirming this in the human body will require extremely expensive and long clinical trials.

The described discovery is the result of several years of academic collaboration between the University of Warsaw, the Medical University of Warsaw and ExploRNA - a university spin-off company founded by Professor Jemielity and his colleagues.

He says that a discovery of this importance would not be possible without this collaboration and mutual complementation of competences. 'Without a doubt, it was the most complicated and expensive project in my scientific career,' he says. 'Personally, it is important for me to prove that scientific research does not have to be a compromise between usefulness and scientific quality. On the contrary, there is perfect synergy of academic collaboration and the goals of a biotechnology company.

'On the one hand, thanks to the collaboration between academia and the company, we can go beyond the limitations we face in the academic team, creating even better science. On the other hand, by developing highly developed technologies derived directly from scientific research, the company gains a significant advantage over its competitors, and the results will almost certainly find practical applications and serve the public. Admittedly, there is still a long way to go, requiring, among other things, a mature system for financing this type of activities, but I believe that this will happen,’ says Professor Jemielity.

The discovery has already been covered by patent protection and licensed by the University of Warsaw to ExploRNA, which deals with further development of the technology and its practical implementation. (PAP)

Katarzyna Czechowicz

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