Gene therapy slows motor neurone disease
Interfering with faulty genes may slow down the progression of motor neurone disease, two mice studies show.
Tests suggest that the technique of RNA interference, while not a cure, can slow this fatal nerve wasting illness.
The UK and Swiss teams report their research into the most common form of motor neurone disease, called amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease, in today's issue of the journal Nature Medicine.
ALS is caused when neurones in the spinal cord die, leading to muscle wasting and total paralysis.
About 10% of cases are inherited, caused by at least 100 different mutations in a protein known as SOD1.
Mice have been genetically engineered to carry this faulty human gene and they develop a disease that looks like human ALS.
The two separate teams of researchers used a gene therapy approach to interfere with the faulty SOD1 gene in mice.
Each team showed that they could delay the disease's effects and help their genetically engineered mice live longer.
The teams used different lentiviruses, long-lived viruses related to HIV that are good at delivering genetic material to cells.
The researchers disabled the viruses, which they then genetically engineered to carry a specific sequence of the genetic material RNA. This interferes with the faulty RNA that the mutant human SOD1 genes in the mice produce.
Using lentiviruses to silence the mutant genes provides "considerable therapeutic benefit by delaying onset and prolonging duration of motor neurone disease", Professor Patrick Aebischer of the Swiss Federal Institute of Technology in Lausanne, Switzerland and colleagues write in their report.
In the second study, a UK team injected its gene therapy into the spines and various muscles of the ALS mutant mice.
When Dr Mimoun Azzouz of Oxford Biomedica and colleagues dissected the mice, they found the treated mice had more healthy motor neurones than untreated mice.
It took twice as long as normal for ALS symptoms to start and the mice lived for 80% of their normal lifespan.