Iron storage within dopamine neurovesicles revealed by chemical nano-imaging.Report as inadecuate

Iron storage within dopamine neurovesicles revealed by chemical nano-imaging. - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 CNAB - Chimie Nucléaire Analytique et Bio-environnementale 2 ESRF - European Synchrotron Radiation Facility 3 Centro Nacional de Aceleradores 4 GIN - Grenoble Institut des Neurosciences

Abstract : Altered homeostasis of metal ions is suspected to play a critical role in neurodegeneration. However, the lack of analytical technique with sufficient spatial resolution prevents the investigation of metals distribution in neurons. An original experimental setup was developed to perform chemical element imaging with a 90 nm spatial resolution using synchrotron-based X-ray fluorescence. This unique spatial resolution, combined to a high brightness, enables chemical element imaging in subcellular compartments. We investigated the distribution of iron in dopamine producing neurons because iron-dopamine compounds are suspected to be formed but have yet never been observed in cells. The study shows that iron accumulates into dopamine neurovesicles. In addition, the inhibition of dopamine synthesis results in a decreased vesicular storage of iron. These results indicate a new physiological role for dopamine in iron buffering within normal dopamine producing cells. This system could be at fault in Parkinson-s disease which is characterized by an increased level of iron in the substantia nigra pars compacta and an impaired storage of dopamine due to the disruption of vesicular trafficking. The re-distribution of highly reactive dopamine-iron complexes outside neurovesicles would result in an enhanced death of dopaminergic neurons.

Author: Richard Ortega - Peter Cloetens - Guillaume Devès - Asunción Carmona - Sylvain Bohic -



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