Decoy molecule draws deadly mosquito-borne virus away from the brain

Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne virus that, in the worst case scenario, can infect the brain and become deadly. It’s notoriously difficult to treat, but now scientists have discovered the protein it latches onto – and used it to create a decoy molecule that draws the virus away from the brain.

Originating in horses, VEEV has been known to spread to humans through mosquito bites. Patients usually experience symptoms like high fevers and headaches, but in the most severe cases it can cross the blood-brain barrier and cause encephalitis. At that point it becomes potentially fatal in around a quarter of patients.

Normally, viruses are known to latch onto a specific protein on the surface of cells, and get inside that way. So for the study, researchers at Washington University School of Medicine in St. Louis set out to first identify the protein VEEV targets.

Using a modified version of the virus that’s infectious but doesn’t cause disease, the team screened for the key protein. They used the CRISPR gene-editing tool to systematically knock out genes in cultured mouse neurons, until they found a batch that VEEV was unable to infect.

With a target in their sights, the researchers then started work on a way to fight back. The mechanism is quite clever – they used a piece of the protein to create a “decoy handle.”

To test it out, the team injected groups of mice with VEEV, either through the skin like a mosquito bite or directly into the brain.