With the help of small RNA molecules called microRNAs, a metabolic and neurodegenerative disorder might be treated using gene therapy.
Patients with Krabbe's disease lack a functioning version of an enzyme called GALC. Transplants of genetically engineered blood stem cells that later develop into white blood cells could potentially deliver a corrected version of GALC. But expressing the protein in the stem cells kills them.
Alessandra Biffi and Luigi Naldini of the San Raffaele Scientific Institute in Milan, Italy, and their colleagues identified gene-silencing microRNAs that are expressed in the stem cells, but not in the mature white blood cells.The researchers then modified the stem cells so that GALC expression was suppressed by a microRNA in the stem cells but not in the white blood cells. As the cells developed, they were able to deliver GALC to diseased tissues in a mouse model of Krabbe's disease.