The term mRNA is now widely recognized because COVID-19 vaccines using mRNA technology have now been given to billions of people. But how does mRNA actually work?

Our bodies constantly create our own mRNA to relay the instructions from our genes to the “assembly line” to make components like enzymes that are essential for our bodies to function. Genes are the “recipes” for creating our body’s components and are located in a protected place called the nucleus, which acts as the “command center” of our cells. The job of mRNA is to carry the instructions (or the “message”) to the cell’s assembly line outside the nucleus, and act as a template to gather the necessary ingredients to assemble the final components.

Sometimes, a person’s genes can carry instructions that do not make sense (known as mutations), which can lead to faulty components (e.g., enzymes) that do not properly work.

In OTC deficiency, the OTC gene contains incorrect instructions that lead to low-functioning or absent OTC enzyme, resulting in illness if not treated.

The mRNA in ARCT-810 is designed to be a template for making OTC enzyme. Arcturus uses its lipid nanoparticle technology, called LUNAR®, to deliver the mRNA template for OTC to the liver, the place where OTC enzyme is made.

Animal studies show that:

ARCT-810 is taken into liver cells and releases the mRNA with the correct instructions to make functional OTC enzyme.

The mRNA is broken down over time and does not enter the nucleus, so it does not have the potential to alter or replace existing genes.

Therefore, it is believed that ARCT-810 will not cause permanent or irreversible changes to DNA.

mRNA cell diagram

At Arcturus, we are developing mRNA medicines designed to treat the underlying cause of genetic diseases like OTC deficiency with the hope of providing meaningful treatment options.