Molecular biology: RNA from blood to brain

It’s now possible to perform gene therapy on the brain via intravenous injection, in mice at least. The finding opens a new potential line of noninvasive treatment for neuronal disease.
Getting any drug into the brain can be a problem because the blood–brain barrier acts as a barricade keeping systemic treatments out. Manjunath N. Swamy and colleagues show that when small fragments of RNA attached to a piece of viral protein are injected into the bloodstream of mice infected with a fatal form of encephalitis, the RNA–protein complex travels to the brain. The protein part binds neuronal cells, delivering the RNA part, which becomes internalised and can silence key genes through a process called RNA interference. The result — about 80% of treated animals survived, whilst all of the non-treated animals died.
Although the method needs tweaking to improve efficiency, the technique may offer a useful way of delivering nucleic acids and small-molecule drugs into the brain.
Author contact:
Manjunath N. Swamy (CBR Institute for Biomedical Research, Boston, MA, USA)
Tel: +1 617 278 3240; E-mail: swamy@cbrinstitute.org