Viral infections are notoriously difficult to treat. When a virus, such as the ones that cause the common cold or the flu, gets into your body, it takes over the molecular machinery of the other cells, so the virus can copy itself. As a result, the virus spreads quickly throughout the body, infecting more cells along the way.
However, scientists in Massachusetts may have found a new way to stop these viruses from replicating themselves using what’s known as CRISPR (clustered regularly interspaced short palindromic repeats), a state-of-the-art gene editing tool. Using a pair of CRISPR molecular scissors, doctors were able to edit out the virus from a series of cells. While the scientists were successful with the experiment, this new antiviral treatment method has yet to be used on humans. Let’s explore how this technology is being used and its potential to stop viruses from spreading.
Viruses and the Human Body
The medical community has long sought to put an end to a series of potentially deadly viruses, including the flu, or influenza. The 2017-2018 flu season was one of the deadliest on record, resulting in high levels of outpatient clinic and emergency department visits for flu-like symptoms and illnesses.
Treating Viral Infections with Molecular Scissors
The gene-editing tool CRISPR can perform a variety of functions inside cells. It comes in many different “flavors” or varieties, each with their own unique properties. A flavor of CRISPR known as Cas9 has been used in medical therapies for treating diseases like sickle cell disease, but it has yet to be used in antiviral treatments. At the Broad Institute in Cambridge, MA, scientists used a flavor of CRISPR known as Cas13, which targets and edits sections of RNA instead of DNA. As a chemical cousin of DNA, RNA is a single-stranded molecule, while DNA is a double-stranded molecule.
Many viruses use RNA to spread copies of themselves, such as the flu and Zika. In this new experiment, scientists used a pair of molecular scissors with Cas13 to cut down the flu virus faster than the virus could copy itself. But it wasn’t easy. The virus needs a lot of RNA to survive in cells, so scientists had to find an RNA target that was unique to the virus they were trying to control. RNA viruses can act like shapeshifters in the body, changing form over time, which is why patients need to get a new flu shot every year.
While the experiment proved to be a success in a series of cells, scientists are still developing an antiviral treatment for humans. As Pardis Sabeti, who oversees the lab at the Broad Institute, said, “There’s still a bunch of things we want to work out, but we feel pretty confident that this will work as a therapy if it can be delivered in the right way.”
In order to be “delivered in the right way”, scientists need to insert Cas13 into the right cells within the infected patient, otherwise the treatment will be ineffective. If Sabeti and her team are successful, CRISPR could be used to treat a range of RNA viruses, including Zika and the flu.
The Future of CRISPR
Cas13 and this new antiviral therapy may only scratch the surface of what CRISPR can do. Scientists continue to discover new flavors of the gene-editing tool, which may help them fight a range of diseases and illnesses by fundamentally altering the DNA of patients. This technology was only discovered six years ago, and it’s already come a long way.
Scientists are currently using Cas9 to treat a woman with sickle cell disease. Early evidence shows this new treatment method may be effective. The newly edited cells are already exceeding doctors’ expectations by producing a crucial protein that’s needed to alleviate complications associated with the genetic blood disorder. While early data are promising, scientists still have a long way to go before CRISPR becomes an established treatment method for sickle cell disease, which currently affects millions of people all over the world.
CRISPR may change the way we treat viruses going forward, putting an end to deadly outbreaks as we know it. As scientists discover new flavors of CRISPR, this technology may even change the face of healthcare altogether.