Small fragments of genetic material that can silence specific genes are showing promise in battling the deadly severe acute respiratory syndrome. Researchers reported August 21 that snippets called interfering RNA can reduce an existing infection in monkeys and help protect them from new ones.
RNA, or ribonucleic acid, transmits information from the DNA that carries the blueprint of life in cells. The small fragments, called siRNA, can be tailored to silence specific genes.
A team led by Patrick Y. Lu of Intradigm Corp. in Rockville, Md., said in the online edition of the journal Nature Medicine that researchers in China and the United States tested two types of siRNA that target different parts of the genome of the SARS virus. Both the SARS virus and the siRNA were delivered by nasal sprays. All the infected animals developed some symptoms. But there was much less lung damage in the animals treated with the RNA fragments, and their body temperature increases were smaller.
The monkeys that got siRNA before infection had the fewest symptoms, the smallest increase in body temperature and the least lung damage.
Intradigm and Top Genomics, Ltd., of Guangzhou, China, are developing RNA therapies for the treatment of human disease. Additional financial support for the research came from the Guangzhou provincial government and the China World Trade Corporation. (Source: Randolphe Schmit, AP, August 21, 2005).