Mice tolerate siRNAs

Small interfering RNAs (siRNAs) can be used to silence genes in mice without triggering an immune response, a report appearing online November 21 from Nature Biotechnology reveals.

"There have been discussions based on cellular studies that suggest immune responses may occur," senior author Mark Davis of the California Institute of Technology in Pasadena told The Scientist. "What is exciting is that siRNAs were well tolerated in animals."

Recent in vitro studies revealed siRNAs could activate the interferon system, raising concerns they might have toxic effects that would limit their potential as therapeutics. "These experiments really needed to be taken to the animal level," said John Rossi of the Beckman Research Institute of the City of Hope in Duarte, Calif., who did not participate in this study.

Davis and colleagues gave mice naked synthetic siRNAs against fatty acid synthase (FAS), c-MYC, or luciferase, either through intraperitoneal injections or via the tail ...