Molecular biologist James Wilson and his colleagues at the University of Pennsylvania are bringing fresh air to gene therapy: They have found a way to make a mouse's lungs manufacture proteins missing in people who suffer from certain genetic diseases. The result could lead to an aerosol spray that would ferry new genes into a patient's lung cells, where the genes would produce the crucial proteins and send them out into the rest of the body.
One major hurdle in gene therapy has been getting engineered DNA to the right part of the body. Previously, researchers injected so-called gene vectors into muscle or liver tissue and hoped circulation would take them to the intended destination. Wilson's team showed that they could program cells to secrete the desired proteins right in the lungs and that these proteins would make their way into the bloodstream. "It's impressive," says Tim Clackson, a molecular biologist who runs the gene-therapy research group at Ariad Pharmaceuticals. "The lung is very accessible, so this adds a third arm to what's currently being explored in clinical trials." So far, Wilson's group has coerced mouse lungs to produce factor IX, a clotting protein lacking in the blood of hemophiliacs, and erythropoietin, whose absence causes symptoms of anemia. But human trials are still at least five years away.