Interfering RNA ( siRNA ) helps monkeys recover from SARS

Researchers at Sun Yat-sen University in Guangdong, China, and Intradigm in Maryland, have reported the first successful use of Interfering RNA (siRNA) against the viral respiratory disease SARS, in primates (Nature Medicine, DOI: 10.1038/nm1280).

Two siRNA sequences that matched bits of the SARS virus genome largely protected macaques against SARS when given as nasal sprays shortly before, or four hours after, infection.

SiRNA works by binding to matching viral sequences to form double-stranded RNA, an anomaly which is automatically destroyed by animal cells. The problem is that siRNA is short-lived in the body, making it hard to deliver to the site of infection before it is degraded. The team gave the siRNA in two solvents which are known to get into lung tissue quickly and are already approved for medical use.

The therapy did not completely prevent disease, but it did limit viral replication and damage to the monkeys’ lungs. In 2003, the SARS virus spread through the world causing lung failure and lethal pneumonia.

Researchers hope that a similar siRNA approach could limit the effects of a pandemic flu virus, which would affect the same tissues as SARS.

Source: New Scientist