A Neuron Can Cause a Domino Effect

Source: Technical University of Munich (TUM).

Summary: A new study by the researchers now shows how the olfactory capacity of the fruit fly ages, and how much this resembles the aging process in the human olfactory system.

Loss of the sense of smell can indicate a neural disease like Alzheimer’s or Parkinson’s disease. However, contrary to previous belief, degenerations in the nervous system do not play a leading role in the loss of the sense of smell with increasing age. Rather, individual nerve cells or classes of nerves are responsible. Some nerve cells in the brain seem to age faster than others. For example, the loss of the olfactory sense is one of the first clinical signs of natural aging. This can be accompanied by a neurodegenerative disease such as Alzheimer’s. A new study by the researchers from the Technical University of Munich now shows how the olfactory capacity of the fruit fly ages, and how much this resembles the aging process in the human olfactory system. The study findings were published in the journal eLife.


Genetic model fly Drosophila melanogaster was investigated for the current study by Professor Grunwald Kadows’ research group on how the odor of animals ages. Credit: Ariane Böhm / TUM

Like humans, the fruit fly loses its powers of smell as it ages. Several key genes and mechanisms were identified that contribute to this aging-associated degeneration. The team examined whether all or only specific neurons of the olfactory circuit were affected. The team found that some neurons are more sensitive than others, and decline faster during aging. They determined that oxidative stress alters specific neuron types, causing the gradual collapse of neural network function. Oxidative stress causes the accumulation of reactive oxygen compounds in the cells or tissue, which can cause temporary or permanent damage and accelerated aging. The study results suggest that age-related degeneration could be significantly delayed by preventing oxidative damage in only one or a few neuron types.

Another possible factor that could play a role in the aging process is the intestinal microbiome. It could be involved in the progression of Parkinson’s disease. The research team has tested the effect of specific microbiota on olfactory aging in fruit flies with the result that certain bacteria have a positive effect and slow down olfactory neurodegeneration.

Prof. Grunwald Kadow said, “These findings and ongoing experiments in the fruit fly model could pave the way for more targeted treatments and therapies”.

More Information: Ashiq Hussain et al, “Inhibition of oxidative stress in cholinergic projection neurons fully rescues aging-associated olfactory circuit degeneration in Drosophila”, eLife (2018). DOI: 10.7554/eLife.32018

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