Drosophila study highlights glial cell toxicity in C9orf72-linked neurodegeneration

A study by Isabel Hubbard and Josh Dubnau, published in PLOS Genetics, uses a Drosophila model to examine the cellular basis of neurodegeneration caused by the C9orf72 repeat expansion — the most frequent genetic cause of both familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD).

The C9orf72 repeat expansion produces both sense and antisense RNA foci and generates dipeptide repeat proteins via repeat-associated non-AUG (RAN) translation. Prior work had established that these products are toxic when expressed in neurons, but the contribution of glial cells — the supportive, non-neuronal cells of the nervous system — had been less thoroughly characterised.

The Hubbard and Dubnau study finds that expression of the C9orf72 repeat in glia produces significant neurodegenerative effects in the fly model, pointing to cell-non-autonomous mechanisms of disease. This is relevant to understanding why neurodegeneration in C9orf72-linked disease is broad and progressive: if glia amplify or propagate toxic signals, therapeutic strategies aimed solely at neurons may be insufficient.

For researchers working on ALS and FTD genetics, the findings add to a growing body of evidence that glial biology is central rather than peripheral to disease pathogenesis. For educators, the paper offers a clear example of how model organisms illuminate the cell biology of complex human neurological conditions.