The elusive goal of developing effective treatments for viral diseases such as AIDS and influenza has been brought closer by dramatic progress in the ability to interfere with viral genetic machinery. The stage was set for a coordinated European effort to accelerate research and stimulate development of new treatments against viral diseases at a recent research conference organised by the European Science Foundation (ESF).
It has been possible for many years to protect against some viral diseases such as polio in advance by vaccination, but there is still no effective treatment for patients once infection has occurred. Furthermore vaccination has not been possible so far against some diseases such as AIDS, and is only partially successful against some others, such as influenza. However there is now the possibility of developing treatments potentially against all viral diseases through drugs based on the recently discovered phenomenon of RNA interference (RNAi), as was discussed at the ESF conference. The interference is performed by small RNA molecules known as siRNAs (small interfering RNAs).
RNA is produced when genes are expressed, normally as an intermediate step in the production of the end product, proteins. In some cases though expression stops with short RNA molecules, which in turn regulate the activity of other genes. Such molecules are called microRNAs, of which siRNAs can be considered a sub-category. It has already been shown that siRNAs occur naturally in plants as a defence mechanism against viral infection, but it is not known whether they occur in animals as Jens Kurreck pointed out, who organized the conference together with Ben Berkhout,. "An important question is whether RNAi is a natural cellular defense mechanism in mammals including humans," said Kurreck.
If it turns out that siRNAs do occur naturally in humans, researchers will attempt to stimulate or reinforce them to treat viral diseases more effectively than they normally do. If they do not occur naturally, then the line would be to create artificial siRNA molecules exploiting knowledge of how plants produce and apply them in their innate immune defences.