Science Bites

A novel technique, called RNA interference (RNAi) has been used successfully to lower cholesterol concentrations in mice. Small molecules of RNA can specifically block particular genes by interfering with their expression. For this experiment, RNA was used that should block a specific gene involved in the synthesis of cholesterol. Because cholesterol synthesising cells express a large number of cholesterol receptors, the researchers attached cholesterol molecules to the RNA. When injected into mice, the complex was taken up by these cells, located mainly in the liver and small intestine. As a result, the animals' concentrations of low density lipoprotein cholesterol decreased by 44%. The scientists argue that their experiment could be a major step forward in the development of RNAi therapeutics as a potential new class of drugs. Possible targets may include a number of widespread conditions such as diabetes, obesity, and cancer. Clinical trials using RNAi to treat macular degeneration are already on their way (www.nature.com/news).

Anticoagulant agents are widely used but carry a serious risk of causing bleeding. A new strategy to control the blood clotting balance more safely is to design drug-antidote pairs using aptamer technology. Aptamers are nucleic acid molecules …