Manganese Accumulates within Golgi Apparatus in Dopaminergic Cells as Revealed by Synchrotron X-ray Fluorescence Nanoimaging

Abstract

Chronic exposure to manganese results in neurological symptoms referred to as manganism and is identified as a risk factor for Parkinson's disease. In vitro, manganese induces cell death in the dopaminergic cells, but the mechanisms of manganese cytotoxicity are still unexplained. In particular, the subcellular distribution of manganese and its interaction with other trace elements needed to be assessed. Applying synchrotron X-ray fluorescence nanoimaging, we found that manganese was located within the Golgi apparatus of PC12 dopaminergic cells at physiologic concentrations. At increasing concentrations, manganese accumulates within the Golgi apparatus until cytotoxic concentrations are reached resulting in a higher cytoplasmic content probably after the Golgi apparatus storage capacity is exceeded. Cell exposure to manganese and brefeldin A, a molecule known to specifically cause the collapse of the Golgi apparatus, results in the striking intracellular redistribution of manganese, which accumulates in the cytoplasm and the nucleus. These results indicate that the Golgi apparatus plays an important role in the cellular detoxification of manganese. In addition manganese exposure induces a decrease in total iron content, which could contribute to the overall neurotoxicity.

Metal imaging in neurodegenerative diseases

“…While the symptoms of manganism and PD are very similar, the globus pallidus (GP) is the most affected brain region in manganism rather than the SN. 104 Due to the disease similarities, manganese is also thought to play a role in PD and is frequently used in PD models.…”

Combined use of hard X-ray phase contrast imaging and X-ray fluorescence microscopy for sub-cellular metal quantification

“…The cells labelled B,C in this work, were exposed to 300 lM of Mn and cell A was exposed to 300 lM of Mn and brefeldin A, a molecule known to cause the apparent collapse of the Golgi stacks (Carmona et al, 2010).…”

Imaging Modalities for Manganese Toxicity

“…This type of direct measurement of tissue Mn makes it unique compared to all other imaging methods discussed in this chapter, which image Mn indirectly, as in MRI, or which image effects of Mn exposure on the body's biochemistry, as in PET and SPECT. To date XRF has found its applications in the study of Mn neurotoxicity in single cell imaging, [129][130][131][132] as well as in high-resolution (order of microns) elemental imaging of ex vivo brain slices of rats exposed to Mn. [133][134][135] The generation of an XRF signal begins with the expulsion of a core electron (e.g.…”

“…131 The same authors, Carmona et al, 136 recently used single cell micro-XRF to compare the cytotoxicity towards dopamine-producing cells of several environmental Mn sources: inorganic compounds of different oxidation state and solubility (MnCl 2 , MnSO 4 , and Mn 2 O 3 ) and organic compounds (MMT, a gasoline additive, and maneb, a diththiocarbamate fungicide). The authors found that maneb exhibited the highest toxicity, followed by MnCl 2 , MnSO 4 and MMT with intermediate toxicity, whereas the insoluble Mn 2 O 3 was the least toxic compound.…”