Delaying motor neurone disease
By blocking the production of a faulty protein in mice, researchers have delayed the onset of motor neurone disease, improved mobility, and extended life-span.
Motor neurone diseases affect the cells that control movement. Most types are 'sporadic', but some are genetic. Spinal and bulbar muscular atrophy (SBMA), also known as Kennedy’s disease, is genetic. It is caused by a mutation on the X-chromosome so the disease only fully affects males. Previous research showed that SBMA is caused by a mutation in the androgen receptor. The mutation produces a faulty protein, which accumulates in the body causing damage to the motor neurons and leading to muscle weakness and wasting.
In the past the team proved that Akt (a cell signalling protein) is able to increase clearance of the faulty protein. In this study they found that insulin-like growth factor 1 (IGF-1) activates the protein in the test tube. To see if the same was true in animals, they bred SBMA mice that expressed high levels of the growth factor in their skeletal muscles. The mice showed increased clearance of the faulty protein and therefore reduced accumulation in the tissue. Importantly these mice also had better mobility, put on weight and lived longer.
For a disease that is currently untreatable, this is a step forward in understanding how it affects the body at molecular level and how it may be treated.