Annoying cold sores and fever blisters are often what come to mind when people think of the herpes virus. But far worse are blindness, birth defects and cancer which have also been linked to a very common form of a virus that up to 90 percent of Americans have been exposed to.
Herpes simplex virus or HSV is a virus that can appear in various parts of the body, most commonly the genitals or mouth. Once we have the virus inside of us, we can’t get rid of it on our own. It can lie in dormancy inside cells for long periods of time until something triggers it to flare up causing various symptoms.
Fighting HSV is not easy, but one method has been to block the enzyme necessary for it replicate. This does help to control the level of the virus in the body, but it does not destroy it.
However, a team from the University Medical Center Utrecht, the Netherlands, has been working on developing a therapy to possibly clear out the herpes from the body by changing the virus’ DNA.
A gene-editing technique called CRISPR/Cas9 genome editing techonology can cut DNA at precise points in a sequence rendering the virus’ DNA incapable of properly repairing itself and therefore unable to function. The research team experimented with cells infected with the herpes virus Epstein-Barr, and found that cutting the DNA in just one area decreased viral activity by 50 percent, but when DNA was cut in two areas this decreased viral activity by 95 percent.
“We could efficiently remove the latent genome from infected cells, essentially curing cells from their invader,” Robert Jan Lebbink, a researcher at the University Medical Center Utrecht said.
The herpes virus responsible for causing cold sore – HSV -1 – was more resistant to CRISPR intrusion. However, when two points were targeted by CRISPR along HSV-1’s genome it was successful at keeping the virus from replicating. One reason as to why CRISPR has a harder time with HSV-1 is that this form of the virus is able to stealthily remain dormant for long periods of time which may make its DNA more tightly compressed. This tight compression can make it more problematic for CRISPR tools to reach and cut the DNA strands while HSV-1 is in its latent phase.
This bullseye targeting by CRISPR is the purpose of what researchers are trying to do in order to fight off and eliminate dormant herpes viruses. The challenge lying ahead for researchers is to be able to deliver CRISPR technology safely and effectively to cells infected with the herpes virus. The hope is to develop techniques that can both target and destroy herpes viruses during both their latent and active phases of infection.