Austrian team improves RNAi 'hairpin' structures for more efficient delivery

Johannes Zuber

Back in 2006, Andrew Fire and Craig Mello won the Nobel Prize in Physiology or Medicine for their discovery of RNA interference's usefulness to "silence" genes. Today, nearly a decade later, the technology is still in limbo due to difficulties delivering the genetic material to cells both efficiently and safely.

Now, researchers at the Austrian Research Institute of Molecular Pathology have furthered the RNAi cause, altering the molecules in a way that improves both targeting and efficiency, according to their findings in the journal Cell Reports.

Johannes Zuber brought his RNAi work, developed with Christof Fellmann at Cold Spring Harbor Laboratory in the U.S., to the institute in Vienna. They had corrected some of the small "hairpin" sequences in the synthetic RNAi backbones to further resemble those existing in nature. By fixing these hairpin structures, they created what they call an "RNAi toolkit" for researchers to use when creating specific treatments, and the result may reduce side effects, as well as make the molecules more effective.

"The basic principles of RNAi are not yet fully understood," Zuber said in a statement. "To shut off a specific gene, one has to test many hairpin molecules, and often only one out of 10 will be effective enough. To improve the method, we took nature as an example."

So for companies like Alnylam ($ALNY), Isis ($ISIS) and Arrowhead ($ARWR), all working toward developing drugs using RNAi technology, improvements in the genetic material itself could help optimize trial results on the way to approval. One of the many hurdles to RNAi effectiveness is the size of the dose necessary to achieve actual gene silencing.

"We are taking the technology from a molecular Beetle to a Lamborghini," Zuber said. "The upgrade is simple and existing reagents can be adapted with minimal effort."

- here's the release