Manganese transporter Slc30a10 controls physiological manganese excretion and toxicity
Courtney J. Mercadante, … , Deepa B. Rao, Thomas B. Bartnikas
Courtney J. Mercadante, … , Deepa B. Rao, Thomas B. Bartnikas
Published September 17, 2019
Citation Information: J Clin Invest. 2019;129(12):5442-5461. https://doi.org/10.1172/JCI129710.
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Research Article Genetics Metabolism

Manganese transporter Slc30a10 controls physiological manganese excretion and toxicity

Abstract

Manganese (Mn), an essential metal and nutrient, is toxic in excess. Toxicity classically results from inhalational exposures in individuals who work in industrial settings. The first known disease of inherited Mn excess, identified in 2012, is caused by mutations in the metal exporter SLC30A10 and is characterized by Mn excess, dystonia, cirrhosis, and polycythemia. To investigate the role of SLC30A10 in Mn homeostasis, we first generated whole-body Slc30a10–deficient mice, which developed severe Mn excess and impaired systemic and biliary Mn excretion. Slc30a10 localized to canalicular membranes of hepatocytes, but mice with liver Slc30a10 deficiency developed minimal Mn excess despite impaired biliary Mn excretion. Slc30a10 also localized to the apical membrane of enterocytes, but mice with Slc30a10 deficiency in small intestines developed minimal Mn excess despite impaired Mn export into the lumen of the small intestines. Finally, mice with Slc30a10 deficiency in liver and small intestines developed Mn excess that was less severe than that observed in mice with whole-body Slc30a10 deficiency, suggesting that additional sites of Slc30a10 expression contribute to Mn homeostasis. Overall, these results indicated that Slc30a10 is essential for Mn excretion by hepatocytes and enterocytes and could be an effective target for pharmacological intervention to treat Mn toxicity.

Authors

Courtney J. Mercadante, Milankumar Prajapati, Heather L. Conboy, Miriam E. Dash, Carolina Herrera, Michael A. Pettiglio, Layra Cintron-Rivera, Madeleine A. Salesky, Deepa B. Rao, Thomas B. Bartnikas

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Figure 6

Slc30a10 is localized to the canalicular hepatocyte membrane.

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Slc30a10 is localized to the canalicular hepatocyte membrane. (A) RNA le...
(A) RNA levels of transporters and cell type–specific markers relative to Hprt1 levels: albumin (hepatocytes), Tek (sinusoidal endothelial cells), Pdgfrb (stellate cells), and Adgre1 (Kupffer cells). For each gene, the cell type with higher expression was set to 1, with the other groups normalized to that value. (B) Tissue Mn levels in 8-week-old Slc30a10+/+, Slc30a10KO/GFP, and Slc30a10GFP/GFP mice. (C) Fluorescence images of 2-month-old Slc30a10+/+ and Slc30a10GFP/GFP frozen liver sections. DAPI (blue); GFP (green). Original magnification, ×20; scale bars: 200 μm; original magnification, ×50 (enlarged inset). (D) Immunofluorescence images of frozen liver sections from 2-month-old Slc30a10GFP/GFP mice. DAPI (blue); anti-MDR1 (α-MDR1) (red). Original magnification, ×20 and ×50 (enlarged inset); scale bars: 200 μm. In A and B, data are presented as individual values and represent the mean ± SEM. In A, 2-tailed P values were calculated by unpaired t test. n = 5 replicates/group. In B, removal of the outliers identified by the ROUT method (0.962, 0.931 for female Slc30a10+/+ brain) resulted in a change in P value versus Slc30a10GFP/KO from P > 0.05 to P < 0.01. P values were calculated by 1-way ANOVA with Tukey’s multiple comparisons test. n = 5–10 replicates/group. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.