Using X-ray fluorescence researchers have demonstrated the consequences of a mutation responsible for a hereditary parkinsonian syndrome: accumulated manganese in the cells appears to disturb protein transport. This work was published in the journal of ACS Chemical Neuroscience.

Parkinsonian syndrome is a set of diseases with symptoms similar to Parkinson's disease. Some are caused by high quantities of manganese, a metal essential to the body at trace levels. This is especially so for a hereditary form of the disease caused by a genetic mutation responsible for a toxic accumulation of manganese in cells.

The authors found that Mn accumulates in the Golgi apparatus of human cells transfected with the disease-causing SLC30A10-Δ105–107 mutant under physiological conditions and after exposure to Mn. In cells expressing the wild-type SLC30A10 protein, cellular Mn content was low after all exposure conditions, confirming efficient Mn efflux.

They have been able to locate manganese inside individual cells, using the fluorescent signature it produces under an X-ray beam. Manganese concentrates essentially in the Golgi apparatus, a cellular compartment which acts as a dispatch center for proteins. The proteins receive a label and are accordingly packaged within vesicles to other compartments, or to the outside of the cell. It is in these vesicles--barely 50 nm in diameter--that manganese accumulates, as the researchers have demonstrated by repeating their experiments with even higher sensitivity and spatial resolution.

The researchers think that this manganese accumulation disturbs protein export towards the outside of the cell, altering nerve cell function and leading to parkinsonian symptoms. This must still be confirmed by reproducing these experiments with neurons from animal models for this disease, which are being developed.

http://www.cnrs.fr/en/how-manganese-produces-parkinsonian-syndrome

https://pubs.acs.org/doi/10.1021/acschemneuro.8b00451