New Herpes Study Reveals 'Significant' Information

Scientists have figured out how the dreaded herpes virus breaks into our cells.

Herpes simplex virus type 1—the major cause of oral herpes—enters the nerve cells by taking over cellular transport processes, according to a new paper in the journal Proceedings of the National Academy of Sciences.

This discovery may help researchers develop new and more effective treatments for this sneaky and surprisingly common virus.

Read more: Compare Top Health Savings Accounts

Herpes simplex type 1 (HSV-1) is mainly responsible for oral herpes. Around 67 percent of people aged under 50 worldwide—3.7 billion—are infected with this virus, which can cause flare-ups of cold sores on and around the mouth. Herpes simplex type 2 (HSV-2) mainly causes genital herpes, with 13 percent of people aged 15–49 in the world—about 490 million people—having an infection from this virus. Both types of the virus can cause symptoms both at the mouth and genital regions, but the majority of oral herpes is caused by HSV-1 and genital by HSV-2.

These viral infections are spread via skin-to-skin contact, usually kissing for HSV-1 and sexual contact for HSV-2, infecting nerve cells. Many people never get any symptoms of a herpes simplex infection, but those that do experience painful blisters at the infected areas, which may recur after long periods of dormancy. Triggers for a recurrent flare-up may include sun exposure, stress, surgery, illnesses or fever. There is no cure yet available for infections by these viruses, as they camp out in the nervous system

According to the new paper, herpes may break into our nerve cells by using structures called microtubules, and use special protein engines named dynein and kinesin to move around.

Dynein is a tiny protein in cells that acts like a little motor, and helps move things around inside the cell. This can include transporting food particles, waste, and other materials to where they need to go. Dynein works by walking along tracks within the cell called microtubules, mostly heading toward the center of the cell. Kinesin is another type of motor protein, like dynein, but it generally moves in the opposite direction. Kinesin "walks" along the same microtubules as dynein, but usually heads toward the outer parts of the cell.

"We are developing vaccines against these viruses and these vaccines were designed specifically to not get into your nervous system," study author Gregory Smith, a professor of microbiology and immunology at Northwestern University, said in a statement. "We knew how to mutate them so they didn't get to the nervous system. But we didn't have a complete understanding mechanistically of why our mutations were so effective."

The researchers—from Northwestern University—describe how they attached special fluorescent markers to the virus to watch how it moved within an infected cell. They discovered that a protein in the virus named pUL37 hijacked and disabled the kinesin of the cell to fast-track its journey into the nucleus of the nerve cell.

"Our findings demonstrate how alphaherpesviruses, such as HSV-1, evolved to become highly efficient at invading the nervous system," study co-author DongHo Kim, a Ph.D. student in the Smith laboratory, said in the statement. "The virus achieves this by spatially and temporally regulating the kinesin motor protein to allow smooth delivery of viral particles to the nucleus. Failure to regulate the kinesin motor will cause it to engage in a tug-of-war with the opposing dynein motor, and the virus fails to move towards one direction or another."

The researchers hope to use these discoveries to potentially create new treatments for herpes infections.

"I think our model adds a significant step in understanding the neuro-invasion process by HSV-1, and I am personally excited to see how we can use this machinery for potential therapies," Kim said.

"With this new understanding, we can now dive deeper into this choreographed process that delivers viral genetic material from the outside world into our neurons," Smith agreed.

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about herpes? Let us know via science@newsweek.com.