Extracellular vesicles: the body’s ‘postal system’

From McGill University by Charlotte Bawol and Junji Nishihata

The human body relies on naturally occurring nanoparticles called extracellular vesicles to transport cellular material. McGill researchers – with support from Moderna – are investigating the properties of these particles, as well as their synthetically produced counterparts, Lipid Nanoparticles, to improve mRNA delivery.

The COVID-19 pandemic made mRNA a household term, but how much do people really know about these multifunctional molecules? Some people may also have heard of lipid nanoparticles (LNPs) which play a key role in protecting the mRNA and helping it get into the right cell making sure mRNA vaccines are safe and effective. But probably few non-scientists have heard of Extracellular Vesicles (EVs).

Before jumping into the world of EVs, perhaps a quick refresher on mRNA is in order: what is mRNA? Simply put, mRNA is a single-stranded RNA molecule that carries the information necessary for protein synthesis to occur. The human body is a giant factory that manufactures millions of proteins each day. These proteins play an essential role in regulating all of our bodily functions, including our immune system. The information provided by mRNA is an essential part of this synthesis.

While mRNA may be a necessary tool for the body, these molecules have an Achilles heel: they are extremely fragile and degrade quickly. When it comes to developing mRNA vaccines, this fragility is a real problem.

Enter LNPs. Made up of a layer of fats, LNPs are synthetically produced particles that act as a protective shell to prevent the mRNA from being broken down. The LNPs further help mRNA to deliver their cargo to the necessary cells in a form that will allow the efficient production of proteins. However, there remains much to learn about the exact mechanisms involved in the intracellular processing of LNPs, with the potential to improve the efficiency of mRNA delivery.