Scientists at the University of California, Los Angeles, have discovered a new cause of brain ageing. According to a study published in the journal Nature Communications, the accumulation of the protein F-actin, which has a structural function in cells, may contribute to cognitive decline with age.
F-actin (filamentous actin) is a type of structural protein that maintains the shape of cells. However, its accumulation in the neurons of aging flies blocks the important process of cellular ‘recycling,’ or autophagy, leading to a decline in neuronal function. Without autophagy, cells cannot efficiently remove damaged components, which over time impairs the body’s cognitive abilities.
The scientists used genetic engineering techniques to reduce the expression of a specific gene, Fhos, responsible for the accumulation of F-actin in the neurons of aging flies. This intervention allowed the team to prevent the protein from accumulating in the flies’ brains, improving cellular recycling and maintaining cognitive function.
During the experiment, they found that dietary restriction and the use of the drug rapamycin also reduced the accumulation of F-actin in the brain. These observations, made at the genetic level, confirmed that low levels of F-actin are associated with more active autophagy and improved cognitive performance.
The results showed that fruit flies that were prevented from accumulating F-actin had their cognitive abilities protected and their healthy lifespan increased by 25 to 30 per cent. This led the scientists to conclude that F-actin accumulation is a key factor in brain aging and declining health.
While the results look promising, the scientists emphasise that similar interventions to prevent F-actin accumulation in humans may be difficult to develop. Nevertheless, the study holds new promise for extending healthy life and maintaining cognitive function in older adults.