RNA Treatment Used to Lower Cholesterol in Mice

Researchers have successfully used a technique that selectively shuts off genes to lower levels of LDL, or "bad" cholesterol, in mice. The findings, reported in the journal Nature, suggest that RNA interference may be a revolutionary development for medical science. NPR's Joe Palca reports.

RNA Interference: An Explainer

Genes are made up of chunks of DNA. Each gene contains the instructions to make a particular protein. Proteins do the work of our cells -- digesting food, releasing energy, sending signals to other cells.

To make a protein, another molecule called RNA (ribonucleic acid) reads the DNA instructions and then directs the protein's assembly. Think of RNA as a construction worker, who actually builds a house after reading an architect's drawings.

Most RNA is single stranded. Until 1998, researchers had thought only single-stranded RNA had an effect on gene expression. But recently, scientists discovered that relatively short, double-stranded RNA can be used to turn off certain genes -- without triggering a defensive response that results in cell suicide. This selective silencing of specific genes is called RNA interference, or RNAi.

In the Nov. 11, 2004, issue of Nature, scientists report they were able to use RNAi to lower cholesterol in mice. The researchers, affiliated with Massachusetts-based Alnylam Pharmaceuticals, used RNAi to turn off ApoB, the gene responsible for making the "bad" cholesterol known as LDL.

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