Â鶹ÒùÔº

'Time machine' enzyme could improve mRNA-based therapeutics

Researchers from the International Institute of Molecular and Cell Biology in Warsaw (IIMCB) have described a new mechanism that improves the efficiency of mRNA-based therapies. The research findings could facilitate the development of novel therapeutics against cancers and infectious diseases.

The scientific experiments were carried out at IIMCB, but important contributions also came from collaborators at the Faculty of Â鶹ÒùÔºics and Faculty of Biology of the University of Warsaw, the Medical University of Warsaw, and the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences. The study by the Polish researchers has just been in Nature.

"mRNA vaccines played a key role in controlling the spread of the pandemic. However, mRNA itself is an exceptionally unstable molecule. This does not affect the safety of the therapy but limits its effectiveness—for example, by shortening the duration of action. A particularly important role in mRNA stability is played by its so-called poly(A) tail. In our research, we examined these limitations," says Prof. Andrzej Dziembowski from the Laboratory of RNA Biology—ERA Chairs Group at the International Institute of Molecular and Cell Biology in Warsaw, one of the lead authors of the study.

His team analyzed the anii-COVID-19 vaccines, Comirnaty and Spikevax, widely used during the pandemic. Both operate similarly: they contain mRNA molecules carrying instructions for producing the S protein, present on the surface of the SARS–CoV–2 coronavirus.

"The mRNA present in vaccines works just like the natural mRNA from our cells. After intramuscular administration, the vaccine's mRNA reaches immune cells, which produce the S protein. Our body learns to recognize it. Thus, if we later encounter the real virus, our organism will be ready to react and prevent the disease," says Dr. Seweryn Mroczek from IIMCB and the University of Warsaw.

As the researchers explain, each mRNA molecule has a poly(A) tail at its end. It is essential for mRNA stability and effective protein production. "We decided to take a closer look at these tails," adds Dr. Mroczek. "We wanted to understand how poly(A) tails change during the vaccine's action," summarizes the scientist.

The researchers used modern technology called nanopore sequencing, which allowed direct reading of sequences of vaccine mRNA molecules, including the poly(A) tails.

"We created specialized software to analyze sequencing data from therapeutic mRNA molecules, focusing on poly(A) tail metabolism," adds Dr. Paweł Krawczyk from Prof. Dziembowski's research group, who was responsible for computational methods.

TENT5A—a time machine for mRNA

A team of Polish researchers from the International Institute of Molecular and Cell Biology in Warsaw collaborated with scientists from other research units from the Ochota Campus. This Warsaw-based scientific hub hosts some of Poland's most prominent research institutes and academic institutions. The team was the first in the world to describe the crucial role of the enzyme TENT5A in extending the aforementioned poly(A) tails of therapeutic mRNA molecules.

"Until now, it was assumed that the poly(A) tail of mRNA therapeutics could only be shortened. Extending it is like flipping over an hourglass—it 'buys' extra time, allowing the mRNA to function significantly longer in cells," explains Dr. Krawczyk.

The enzyme TENT5A is naturally present in certain cells of our body. Its role is to add building blocks to the mRNA's poly(A) tail.

"We have demonstrated that TENT5A makes mRNA molecules more stable, enabling longer-lasting and more effective production of antigens—substances that trigger the body's immune response," clarifies Dr. Krawczyk.

"Stabilization of mRNA molecules by the TENT5A enzyme is a mechanism that has been poorly understood so far, yet it is universal. It holds enormous potential for medicine, as extensive research is currently underway into various applications of mRNA as therapeutics," adds Prof. Dziembowski.

Macrophages—the key to vaccine effectiveness

The study also allowed researchers to understand which type of cells plays the most important role in the action of mRNA vaccines. Scientists have proved these to be macrophages. These immune cells are responsible for capturing and neutralizing "intruders." After vaccine administration, macrophages migrate to the injection site, take up mRNA carried in special lipid molecules, and subsequently produce the antigen encoded in them.

"Already in the early stages of our research, we observed that the poly(A) tail is extended in macrophages, but at that time we did not realize how crucial these cells were," says Dr. Mroczek from the Laboratory of RNA Biology at IIMCB. "During the course of the study, we demonstrated that the absence of TENT5A in macrophages reduces vaccine efficacy."

Researchers from the International Institute of Molecular and Cell Biology in Warsaw emphasize that despite the breakthrough findings, knowledge about mRNA metabolism still requires deeper understanding. "In future studies within the Virtual Research Institute, we plan to use our discoveries to develop improved mRNA-based medicines," says Prof. Dziembowski.

The research that led to the publication was conducted using the IN-MOL-CELL Infrastructure of the International Institute of Molecular and Cell Biology in Warsaw.

As the researchers from IIMCB emphasize, the publication would not have been possible without the dedication and skills of all team members. The scientific experiments were carried out at IIMCB, but important contributions also came from collaborators at the University of Warsaw, the Medical University of Warsaw, and the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences.