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J Biol Chem. 2019 Feb 8;294(6):1860-1876. doi: 10.1074/jbc.RA118.005628. Epub 2018 Dec 17.

SLC30A10 transporter in the digestive system regulates brain manganese under basal conditions while brain SLC30A10 protects against neurotoxicity.

Author information

1
From the Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience and.
2
the Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California 95064, and.
3
the Mouse Genetic Engineering Facility, University of Texas, Austin, Texas 78712.
4
the Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461.
5
From the Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience and som@austin.utexas.edu.

Abstract

The essential metal manganese becomes neurotoxic at elevated levels. Yet, the mechanisms by which brain manganese homeostasis is regulated are unclear. Loss-of-function mutations in SLC30A10, a cell surface-localized manganese efflux transporter in the brain and liver, induce familial manganese neurotoxicity. To elucidate the role of SLC30A10 in regulating brain manganese, we compared the phenotypes of whole-body and tissue-specific Slc30a10 knockout mice. Surprisingly, unlike whole-body knockouts, brain manganese levels were unaltered in pan-neuronal/glial Slc30a10 knockouts under basal physiological conditions. Further, although transport into bile is a major route of manganese excretion, manganese levels in the brain, blood, and liver of liver-specific Slc30a10 knockouts were only minimally elevated, suggesting that another organ compensated for loss-of-function in the liver. Additional assays revealed that SLC30A10 was also expressed in the gastrointestinal tract. In differentiated enterocytes, SLC30A10 localized to the apical/luminal domain and transported intracellular manganese to the lumen. Importantly, endoderm-specific knockouts, lacking SLC30A10 in the liver and gastrointestinal tract, had markedly elevated manganese levels in the brain, blood, and liver. Thus, under basal physiological conditions, brain manganese is regulated by activity of SLC30A10 in the liver and gastrointestinal tract, and not the brain or just the liver. Notably, however, brain manganese levels of endoderm-specific knockouts were lower than whole-body knockouts, and only whole-body knockouts exhibited manganese-induced neurobehavioral defects. Moreover, after elevated exposure, pan-neuronal/glial knockouts had higher manganese levels in the basal ganglia and thalamus than controls. Therefore, when manganese levels increase, activity of SLC30A10 in the brain protects against neurotoxicity.

KEYWORDS:

Parkinson disease; SLC30; ZnT; ZnT10; cation diffusion facilitator; manganese; metal homeostasis; mouse genetics; neurotoxicity; parkinsonism; solute carrier; thyroid; toxicity; transporter

PMID:
30559290
PMCID:
PMC6369308
[Available on 2020-02-08]
DOI:
10.1074/jbc.RA118.005628
[Indexed for MEDLINE]

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