In just a few months, vaccines against Covid-19 have changed the game in the fight against the pandemic. These vaccines are said to be messenger RNA. What is it exactly? Could this technology also revolutionize medicine in other fields?
THE’RNA messenger for Messenger Ribonucleic Acid, was discovered in 1961 by two French scientists: Francois Jacob and Jacques Monod. In 1965, they received the Nobel Prize for this exceptional scientific breakthrough.
What is messenger RNA
THE’DNA (Deoxyribonucleic acid) contains the genetic information, i.e. the data necessary for the synthesis of protein of our body. DNA is stored inside the nucleus of cells while proteins are synthesized outside the nucleus. DNA not being able to leave the nucleus, how is the information transmitted to the place of synthesis? Thanks to messenger RNA, hence its name! Messenger RNAs are copies of a DNA fragment which circulates from the nucleus to the place of production of proteins. Once the protein is synthesized, the messenger RNA that served as a “manufacturing blueprint” is quickly destroyed.
How do messenger RNA vaccines work?
It is on the basis of this physiological system that the vaccines messenger RNAs have been ingeniously designed. Vaccines contain a strand of messenger RNA encoding a key protein of the Covid-19 virus, a protein however incapable of making us get sick. Since messenger RNA is very fragile, the strand is surrounded by a lipid envelope to protect it.
When the vaccine enters the cells, they will synthesize the harmless viral protein. The presence of this protein will trigger the production of antibodies by our body. If we meet the virus, we will already have the weapons to defend ourselves!
What are the other applications of messenger RNA?
As such, all diseases could potentially benefit from a therapy preventive or curative by messenger RNA! The possibilities are limitless ; it is only a question of time and resources. If a disease is caused by an altered gene, messenger RNA could in theory stimulate the synthesis of the deficient protein orenzyme missing. If a disease is linked to an infectious agent, the messenger RNA could stimulate the synthesis of the necessary antibodies, as a preventive (vaccine) or in curative (therapy). Research is advancing in many therapeutic areas. Here are two examples of messenger RNA therapies already in clinical test !
In itself, all diseases could potentially benefit from preventive or curative messenger RNA therapy!
The cystic fibrosis is a genetic disease in which the protein CFTR (Cystic Fibrosis Transmembrane conductance Regulator) is no longer synthesized correctly. A phase II clinical trial is underway to test messenger RNA therapy to restore protein synthesis. This potential drug presents a particularity of size. It was designed to be nebulized and thus be deposited directly on the cells of interest, at the pulmonary level. The process of dispensing by nebulization is very complex. Indeed, our lungs were designed to prevent these types of particles from entering the body and a workaround had to be found.
CMV infection (CytoMegaloVirus) is usually little or no symptomatic. On the other hand, if the contamination takes place during the pregnancy, the consequences can be significant for the unborn baby : mental retardation, deafness, severe disabilities … A solution could be to vaccinate women of childbearing age. A phase III clinical trial is underway to test a messenger RNA vaccine to stimulate the immune system to trigger the synthesis of antibodies against the virus and thus avoid any infection of the pregnant woman.
Others projects are underway in the pancreatic cancer, HIV, rage, flu, melanoma, the cardiomyopathies, multiple sclerosis…
The challenges of messenger RNA therapies
If the synthesis of messenger RNA strands is fairly simple and rapid, it is necessary to find for each of them the most efficient transport system possible according to the pathology. On the one hand, it is necessary to protect the messenger RNA, which is fragile. On the other hand, the drug must be delivered as specifically as possible, only to the target to be treated for avoid side effects.
Another challenge with this type of therapy is overcoming the fears of the general public. Messenger RNAs can pass from inside the nucleus to outside the nucleus, but not the other way around. There is therefore no risk that the messenger RNA resulting from a therapy could modify our genetic heritage!
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