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Gurol KC, Jursa T, Cho EJ, Fast W, Dalby KN, Smith DR, Mukhopadhyay S. PHD2 enzyme is an intracellular manganese sensor that initiates the homeostatic response against elevated manganese. Proc Natl Acad Sci U S A 2024; 121:e2402538121. [PMID: 38905240 DOI: 10.1073/pnas.2402538121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 05/24/2024] [Indexed: 06/23/2024] Open
Abstract
Intracellular sensors detect changes in levels of essential metals to initiate homeostatic responses. But, a mammalian manganese (Mn) sensor is unknown, representing a major gap in understanding of Mn homeostasis. Using human-relevant models, we recently reported that: 1) the primary homeostatic response to elevated Mn is upregulation of hypoxia-inducible factors (HIFs), which increases expression of the Mn efflux transporter SLC30A10; and 2) elevated Mn blocks the prolyl hydroxylation of HIFs by prolyl hydroxylase domain (PHD) enzymes, which otherwise targets HIFs for degradation. Thus, the mammalian mechanism for sensing elevated Mn likely relates to PHD inhibition. Moreover, 1) Mn substitutes for a catalytic iron (Fe) in PHD structures; and 2) exchangeable cellular levels of Fe and Mn are comparable. Therefore, we hypothesized that elevated Mn directly inhibits PHD by replacing its catalytic Fe. In vitro assays using catalytically active PHD2, the primary PHD isoform, revealed that Mn inhibited, and Fe supplementation rescued, PHD2 activity. However, a mutation in PHD2 (D315E) that selectively reduced Mn binding without substantially impacting Fe binding or enzymatic activity resulted in complete insensitivity of PHD2 to Mn in vitro. Additionally, hepatic cells expressing full-length PHD2D315E were less sensitive to Mn-induced HIF activation and SLC30A10 upregulation than PHD2wild-type. These results: 1) define a fundamental Mn sensing mechanism for controlling Mn homeostasis-elevated Mn inhibits PHD2, which functions as a Mn sensor, by outcompeting its catalytic Fe, and PHD2 inhibition activates HIF signaling to up-regulate SLC30A10; and 2) identify a unique mode of metal sensing that may have wide applicability.
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Affiliation(s)
- Kerem C Gurol
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712
| | - Thomas Jursa
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064
| | - Eun Jeong Cho
- College of Pharmacy, Targeted Therapeutic Drug Discovery and Development Program, The University of Texas at Austin, Austin, TX 78712
| | - Walter Fast
- Division of Chemical Biology and Drug Discovery, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712
| | - Kevin N Dalby
- College of Pharmacy, Targeted Therapeutic Drug Discovery and Development Program, The University of Texas at Austin, Austin, TX 78712
- Division of Chemical Biology and Drug Discovery, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712
| | - Donald R Smith
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712
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2
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Sun J, Xie F, Wang J, Luo J, Chen T, Jiang Q, Xi Q, Liu GE, Zhang Y. Integrated meta-omics reveals the regulatory landscape involved in lipid metabolism between pig breeds. MICROBIOME 2024; 12:33. [PMID: 38374121 PMCID: PMC10877772 DOI: 10.1186/s40168-023-01743-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/19/2023] [Indexed: 02/21/2024]
Abstract
BACKGROUND Domesticated pigs serve as an ideal animal model for biomedical research and also provide the majority of meat for human consumption in China. Porcine intramuscular fat content associates with human health and diseases and is essential in pork quality. The molecular mechanisms controlling lipid metabolism and intramuscular fat accretion across tissues in pigs, and how these changes in response to pig breeds, remain largely unknown. RESULTS We surveyed the tissue-resident cell types of the porcine jejunum, colon, liver, and longissimus dorsi muscle between Lantang and Landrace breeds by single-cell RNA sequencing. Combining lipidomics and metagenomics approaches, we also characterized gene signatures and determined key discriminating markers of lipid digestibility, absorption, conversion, and deposition across tissues in two pig breeds. In Landrace, lean-meat swine mainly exhibited breed-specific advantages in lipid absorption and oxidation for energy supply in small and large intestinal epitheliums, nascent high-density lipoprotein synthesis for reverse cholesterol transport in enterocytes and hepatocytes, bile acid formation, and secretion for fat emulsification in hepatocytes, as well as intestinal-microbiota gene expression involved in lipid accumulation product. In Lantang, obese-meat swine showed a higher synthesis capacity of chylomicrons responsible for high serum triacylglycerol levels in small intestinal epitheliums, the predominant characteristics of lipid absorption in muscle tissue, and greater intramuscular adipcytogenesis potentials from muscular fibro-adipogenic progenitor subpopulation. CONCLUSIONS The findings enhanced our understanding of the cellular biology of lipid metabolism and opened new avenues to improve animal production and human diseases. Video Abstract.
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Affiliation(s)
- Jiajie Sun
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Fang Xie
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Jing Wang
- Institute of Animal Husbandry and Veterinary Medicine, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China
| | - Junyi Luo
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Ting Chen
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Qingyan Jiang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Qianyun Xi
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China.
| | - George E Liu
- Animal Genomics and Improvement Laboratory, USDA-ARS, BARC-East, Beltsville, MD, 20705, USA.
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, 510642, China.
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Warden A, Mayfield RD, Gurol KC, Hutchens S, Liu C, Mukhopadhyay S. Loss of SLC30A10 manganese transporter alters expression of neurotransmission genes and activates hypoxia-inducible factor signaling in mice. Metallomics 2024; 16:mfae007. [PMID: 38285613 PMCID: PMC10883138 DOI: 10.1093/mtomcs/mfae007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/16/2024] [Indexed: 01/31/2024]
Abstract
The essential metal manganese (Mn) induces neuromotor disease at elevated levels. The manganese efflux transporter SLC30A10 regulates brain Mn levels. Homozygous loss-of-function mutations in SLC30A10 induce hereditary Mn neurotoxicity in humans. Our prior characterization of Slc30a10 knockout mice recapitulated the high brain Mn levels and neuromotor deficits reported in humans. But, mechanisms of Mn-induced motor deficits due to SLC30A10 mutations or elevated Mn exposure are unclear. To gain insights into this issue, we characterized changes in gene expression in the basal ganglia, the main brain region targeted by Mn, of Slc30a10 knockout mice using unbiased transcriptomics. Compared with littermates, >1000 genes were upregulated or downregulated in the basal ganglia sub-regions (i.e. caudate putamen, globus pallidus, and substantia nigra) of the knockouts. Pathway analyses revealed notable changes in genes regulating synaptic transmission and neurotransmitter function in the knockouts that may contribute to the motor phenotype. Expression changes in the knockouts were essentially normalized by a reduced Mn chow, establishing that changes were Mn dependent. Upstream regulator analyses identified hypoxia-inducible factor (HIF) signaling, which we recently characterized to be a primary cellular response to elevated Mn, as a critical mediator of the transcriptomic changes in the basal ganglia of the knockout mice. HIF activation was also evident in the liver of the knockout mice. These results: (i) enhance understanding of the pathobiology of Mn-induced motor disease; (ii) identify specific target genes/pathways for future mechanistic analyses; and (iii) independently corroborate the importance of the HIF pathway in Mn homeostasis and toxicity.
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Affiliation(s)
- Anna Warden
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712, USA
| | - R Dayne Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712, USA
| | - Kerem C Gurol
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Steven Hutchens
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Chunyi Liu
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
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4
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Ghosn ZA, Sparks KM, Spaulding JL, Vutukuri S, Ahmed MJJ, VanBerkum MFA. Divalent metal content in diet affects severity of manganese toxicity in Drosophila. Biol Open 2024; 13:bio060204. [PMID: 38117005 PMCID: PMC10810561 DOI: 10.1242/bio.060204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023] Open
Abstract
Dysregulation of manganese (Mn) homeostasis is a contributing factor in many neuro-degenerative diseases. Adult Drosophila are sensitive to excessive levels of dietary Mn, dying relatively early, and exhibiting biochemical and mobility changes reminiscent of Parkinsonian conditions. To further study Mn homeostasis in Drosophila, we sought to test lower levels of dietary Mn (5 mM) and noted a striking difference in Canton-S adult survivorship on different food. On a cornmeal diet, Mn-treated flies live only about half as long as untreated siblings. Yet, with the same Mn concentration in a molasses diet, adults survive about 80% as long as untreated siblings, and adults raised on a sucrose-yeast diet are completely insensitive to this low dose of dietary Mn. By manipulating metal ion content in the cornmeal diet, and measuring the metal content in each diet, we traced the difference in lifespan to the levels of calcium and magnesium in the food, suggesting that these ions are involved in Mn uptake and/or use. Based on these findings, it is recommended that the total dietary load of metal ions be considered when assessing Mn toxicity.
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Affiliation(s)
- Zahraa A. Ghosn
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Kailynn M. Sparks
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Jacob L. Spaulding
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Sanjana Vutukuri
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Mirza J. J. Ahmed
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Mark F. A. VanBerkum
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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Hutchens S, Jursa TP, Melkote A, Grant SM, Smith DR, Mukhopadhyay S. Hepatic and intestinal manganese excretion are both required to regulate brain manganese during elevated manganese exposure. Am J Physiol Gastrointest Liver Physiol 2023; 325:G251-G264. [PMID: 37461848 PMCID: PMC10511180 DOI: 10.1152/ajpgi.00047.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/26/2023] [Accepted: 07/10/2023] [Indexed: 08/15/2023]
Abstract
Manganese (Mn) is essential but neurotoxic at elevated levels. Under physiological conditions, Mn is primarily excreted by the liver, with the intestines playing a secondary role. Recent analyses of tissue-specific Slc30a10 or Slc39a14 knockout mice (SLC30A10 and SLC39A14 are Mn transporters) revealed that, under physiological conditions: 1) excretion of Mn by the liver and intestines is a major pathway that regulates brain Mn; and surprisingly, 2) the intestines compensate for loss of hepatic Mn excretion in controlling brain Mn. The unexpected importance of the intestines in controlling physiological brain Mn led us to determine the role of hepatic and intestinal Mn excretion in regulating brain Mn during elevated Mn exposure. We used liver- or intestine-specific Slc30a10 knockout mice as models to inhibit hepatic or intestinal Mn excretion. Compared with littermates, both knockout strains exhibited similar increases in brain Mn after elevated Mn exposure in early or later life. Thus, unlike physiological conditions, both hepatic and intestinal Mn excretion are required to control brain Mn during elevated Mn exposure. However, brain Mn levels of littermates and both knockout strains exposed to elevated Mn only in early life were normalized in later life. Thus, hepatic and intestinal Mn excretion play compensatory roles in clearing brain Mn accumulated by early life Mn exposure. Finally, neuromotor assays provided evidence consistent with a role for hepatic and intestinal Mn excretion in functionally modulating Mn neurotoxicity during Mn exposure. Put together, these findings substantially enhance understanding of the regulation of brain Mn by excretion.NEW & NOTEWORTHY This article shows that, in contrast with expectations from prior studies and physiological conditions, excretion of manganese by the intestines and liver is equally important in controlling brain manganese during human-relevant manganese exposure. The results provide foundational insights about the interorgan mechanisms that control brain manganese homeostasis at the organism level and have important implications for the development of therapeutics to treat manganese-induced neurological disease.
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Affiliation(s)
- Steven Hutchens
- Division of Pharmacology and Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States
| | - Thomas P Jursa
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, California, United States
| | - Ashvini Melkote
- Division of Pharmacology and Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States
| | - Stephanie M Grant
- Division of Pharmacology and Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States
| | - Donald R Smith
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, California, United States
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology and Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States
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6
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Taylor CA, Grant SM, Jursa T, Melkote A, Fulthorpe R, Aschner M, Smith DR, Gonzales RA, Mukhopadhyay S. SLC30A10 manganese transporter in the brain protects against deficits in motor function and dopaminergic neurotransmission under physiological conditions. Metallomics 2023; 15:mfad021. [PMID: 36990693 PMCID: PMC10103839 DOI: 10.1093/mtomcs/mfad021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/28/2023] [Indexed: 03/31/2023]
Abstract
Loss-of-function mutations in SLC30A10 induce hereditary manganese (Mn)-induced neuromotor disease in humans. We previously identified SLC30A10 to be a critical Mn efflux transporter that controls physiological brain Mn levels by mediating hepatic and intestinal Mn excretion in adolescence/adulthood. Our studies also revealed that in adulthood, SLC30A10 in the brain regulates brain Mn levels when Mn excretion capacity is overwhelmed (e.g. after Mn exposure). But, the functional role of brain SLC30A10 under physiological conditions is unknown. We hypothesized that, under physiological conditions, brain SLC30A10 may modulate brain Mn levels and Mn neurotoxicity in early postnatal life because body Mn excretion capacity is reduced in this developmental stage. We discovered that Mn levels of pan-neuronal/glial Slc30a10 knockout mice were elevated in specific brain regions (thalamus) during specific stages of early postnatal development (postnatal day 21), but not in adulthood. Furthermore, adolescent or adult pan-neuronal/glial Slc30a10 knockouts exhibited neuromotor deficits. The neuromotor dysfunction of adult pan-neuronal/glial Slc30a10 knockouts was associated with a profound reduction in evoked striatal dopamine release without dopaminergic neurodegeneration or changes in striatal tissue dopamine levels. Put together, our results identify a critical physiological function of brain SLC30A10-SLC30A10 in the brain regulates Mn levels in specific brain regions and periods of early postnatal life, which protects against lasting deficits in neuromotor function and dopaminergic neurotransmission. These findings further suggest that a deficit in dopamine release may be a likely cause of early-life Mn-induced motor disease.
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Affiliation(s)
- Cherish A Taylor
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Stephanie M Grant
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Thomas Jursa
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | - Ashvini Melkote
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Rebecca Fulthorpe
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx NY 10461, USA
| | - Donald R Smith
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | - Rueben A Gonzales
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy; and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
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Li W, Jin H, Xie H, Wang D. Progress in comprehensive utilization of electrolytic manganese residue: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:48837-48853. [PMID: 36884169 DOI: 10.1007/s11356-023-26156-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/23/2023] [Indexed: 04/16/2023]
Abstract
Electrolytic manganese residue (EMR) is a solid waste produced in the process of electrolytic manganese metal (EMM) production. In recent years, the accumulation of EMR has caused increasingly serious environmental problems. To better understand the state of EMR recycling in recent years, this paper used a comprehensive literature database to conduct a statistical analysis of EMR-related publications from 2010 to 2022 from two perspectives: harmless green treatment and resource utilization. The results showed that the research on the comprehensive utilization of EMR mainly focused on the fields of chemical hazard-free treatment and manufacturing building materials. The related studies of EMR in the fields of biological harmlessness, applied electric field harmlessness, manganese series materials, adsorbents, geopolymers, glass-ceramics, catalysts, and agriculture were also reported. Finally, we put forward some suggestions to solve the EMR problem, hoping that this work could provide a reference for the clean disposal and efficient utilization of EMR.
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Affiliation(s)
- Wenlei Li
- College of Materials and Metallurgy, Guizhou University, 550025, Guiyang, China
| | - Huixin Jin
- College of Materials and Metallurgy, Guizhou University, 550025, Guiyang, China.
| | - Hongyan Xie
- College of Materials and Metallurgy, Guizhou University, 550025, Guiyang, China
| | - Duolun Wang
- College of Materials and Metallurgy, Guizhou University, 550025, Guiyang, China
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Gurol KC, Li D, Broberg K, Mukhopadhyay S. Manganese efflux transporter SLC30A10 missense polymorphism T95I associated with liver injury retains manganese efflux activity. Am J Physiol Gastrointest Liver Physiol 2023; 324:G78-G88. [PMID: 36414535 PMCID: PMC9829465 DOI: 10.1152/ajpgi.00213.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/18/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022]
Abstract
The activity of the manganese (Mn) efflux transporter SLC30A10 in the liver and intestines is critical for Mn excretion and preventing Mn toxicity. Homozygous loss-of-function mutations in SLC30A10 are a well-established cause of hereditary Mn toxicity. But, the relationship between more common SLC30A10 polymorphisms, Mn homeostasis, and disease is only recently emerging. In 2021, the first coding SNP in SLC30A10 (T95I) was associated with liver disease raising the hypothesis that the T95I substitution may induce disease by inhibiting the Mn efflux function of SLC30A10. Here, we test this hypothesis using structural, viability, and metal quantification approaches. Analyses of a predicted structure of SLC30A10 revealed that the side chain of T95 pointed away from the putative Mn-binding cavity, raising doubts about the impact of the T95I substitution on SLC30A10 function. In HeLa or HepG2 cells, overexpression of SLC30A10-WT or T95I resulted in comparable reductions of intracellular Mn levels and protection against Mn-induced cell death. Furthermore, ΔSLC30A10 HepG2 cells, generated using CRISPR/Cas9, exhibited elevated Mn levels and heightened sensitivity to Mn-induced cell death, and these phenotypic changes were similarly rescued by expression of SLC30A10-WT or T95I. Finally, turnover rates of SLC30A10-WT or T95I were also comparable. In summary, our results indicate that the Mn transport activity of SLC30A10-T95I is essentially comparable to the WT protein. Our findings imply that SLC30A10-T95I either has a complex association with liver injury that extends beyond the simple reduction in SLC30A10 activity or alternatively the T95I mutation lacks a causal role in liver disease.NEW & NOTEWORTHY This study demonstrates that the T95I polymorphism in the manganese transporter SLC30A10, which has been associated with liver disease in human GWAS studies, does not impact transporter function in cell culture. These findings raise doubts about the causal relationship of the T95I polymorphism with human disease and highlight the importance of validating GWAS findings using mechanistic approaches.
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Affiliation(s)
- Kerem C Gurol
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
- Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
| | - Danyang Li
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
- Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
| | - Karin Broberg
- Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
- Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
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Gurol KC, Aschner M, Smith DR, Mukhopadhyay S. Role of excretion in manganese homeostasis and neurotoxicity: a historical perspective. Am J Physiol Gastrointest Liver Physiol 2022; 322:G79-G92. [PMID: 34786983 PMCID: PMC8714252 DOI: 10.1152/ajpgi.00299.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The essential metal manganese (Mn) induces incurable neurotoxicity at elevated levels that manifests as parkinsonism in adults and fine motor and executive function deficits in children. Studies on Mn neurotoxicity have largely focused on the role and mechanisms of disease induced by elevated Mn exposure from occupational or environmental sources. In contrast, the critical role of excretion in regulating Mn homeostasis and neurotoxicity has received less attention although 1) studies on Mn excretion date back to the 1920s; 2) elegant radiotracer Mn excretion assays in the 1940s to 1960s established the routes of Mn excretion; and 3) studies on patients with liver cirrhosis in the 1990s to 2000s identified an association between decreased Mn excretion and the risk of developing Mn-induced parkinsonism in the absence of elevated Mn exposure. Notably, the last few years have seen renewed interest in Mn excretion largely driven by the discovery that hereditary Mn neurotoxicity due to mutations in SLC30A10 or SLC39A14 is caused, at least in part, by deficits in Mn excretion. Quite remarkably, some of the recent results on SLC30A10 and SLC39A14 provide explanations for observations made ∼40-50 years ago. The goal of the current review is to integrate the historic studies on Mn excretion with more contemporary recent work and provide a comprehensive state-of-the-art overview of Mn excretion and its role in regulating Mn homeostasis and neurotoxicity. A related goal is to discuss the significance of some of the foundational studies on Mn excretion so that these highly consequential earlier studies remain influential in the field.
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Affiliation(s)
- Kerem C. Gurol
- 1Division of Pharmacology & Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
| | - Michael Aschner
- 2Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| | - Donald R. Smith
- 3Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California
| | - Somshuvra Mukhopadhyay
- 1Division of Pharmacology & Toxicology, College of Pharmacy, and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
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Up-regulation of the manganese transporter SLC30A10 by hypoxia-inducible factors defines a homeostatic response to manganese toxicity. Proc Natl Acad Sci U S A 2021; 118:2107673118. [PMID: 34446561 DOI: 10.1073/pnas.2107673118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Manganese (Mn) is an essential metal that induces incurable parkinsonism at elevated levels. However, unlike other essential metals, mechanisms that regulate mammalian Mn homeostasis are poorly understood, which has limited therapeutic development. Here, we discovered that the exposure of mice to a translationally relevant oral Mn regimen up-regulated expression of SLC30A10, a critical Mn efflux transporter, in the liver and intestines. Mechanistic studies in cell culture, including primary human hepatocytes, revealed that 1) elevated Mn transcriptionally up-regulated SLC30A10, 2) a hypoxia response element in the SLC30A10 promoter was necessary, 3) the transcriptional activities of hypoxia-inducible factor (HIF) 1 or HIF2 were required and sufficient for the SLC30A10 response, 4) elevated Mn activated HIF1/HIF2 by blocking the prolyl hydroxylation of HIF proteins necessary for their degradation, and 5) blocking the Mn-induced up-regulation of SLC30A10 increased intracellular Mn levels and enhanced Mn toxicity. Finally, prolyl hydroxylase inhibitors that stabilize HIF proteins and are in advanced clinical trials for other diseases reduced intracellular Mn levels and afforded cellular protection against Mn toxicity and also ameliorated the in vivo Mn-induced neuromotor deficits in mice. These findings define a fundamental homeostatic protective response to Mn toxicity-elevated Mn levels activate HIF1 and HIF2 to up-regulate SLC30A10, which in turn reduces cellular and organismal Mn levels, and further indicate that it may be possible to repurpose prolyl hydroxylase inhibitors for the management of Mn neurotoxicity.
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11
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Li D, Mukhopadhyay S. A three-pocket model for substrate coordination and selectivity by the nucleotide sugar transporters SLC35A1 and SLC35A2. J Biol Chem 2021; 297:101069. [PMID: 34384782 PMCID: PMC8411240 DOI: 10.1016/j.jbc.2021.101069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 10/25/2022] Open
Abstract
The CMP-sialic acid transporter SLC35A1 and UDP-galactose transporter SLC35A2 are two well-characterized nucleotide sugar transporters with distinctive substrate specificities. Mutations in either induce congenital disorders of glycosylation. Despite the biomedical relevance, mechanisms of substrate specificity are unclear. To address this critical issue, we utilized a structure-guided mutagenesis strategy and assayed a series of SLC35A2 and SLC35A1 mutants using a rescue approach. Our results suggest that three pockets in the central cavity of each transporter provide substrate specificity. The pockets comprise (1) nucleobase (residues E52, K55, and Y214 of SLC35A1; E75, K78, N235, and G239 of SLC35A2); (2) middle (residues Q101, N102, and T260 of SLC35A1; Q125, N126, Q129, Y130, and Q278 of SLC35A2); and (3) sugar (residues K124, T128, S188, and K272 of SLC35A1; K148, T152, S213, and K297 of SLC35A2) pockets. Within these pockets, two components appear to be especially critical for substrate specificity. Y214 (for SLC35A1) and G239 (for SLC35A2) in the nucleobase pocket appear to discriminate cytosine from uracil. Furthermore, Q129 and Q278 of SLC35A2 in the middle pocket appear to interact specifically with the β-phosphate of UDP while the corresponding A105 and A253 residues in SLC35A1 do not interact with CMP, which lacks a β-phosphate. Overall, our findings contribute to a molecular understanding of substrate specificity and coordination in SLC35A1 and SLC35A2, and have important implications for the understanding and treatment of diseases associated with mutations or dysregulations of these two transporters.
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Affiliation(s)
- Danyang Li
- Division of Pharmacology & Toxicology, College of Pharmacy, Institute for Cellular & Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy, Institute for Cellular & Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712.
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12
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Prajapati M, Pettiglio MA, Conboy HL, Mercadante CJ, Hojyo S, Fukada T, Bartnikas TB. Characterization of in vitro models of SLC30A10 deficiency. Biometals 2021; 34:573-588. [PMID: 33713241 DOI: 10.1007/s10534-021-00296-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/26/2021] [Indexed: 11/25/2022]
Abstract
Manganese (Mn), an essential metal, can be toxic at elevated levels. In 2012, the first inherited cause of Mn excess was reported in patients with mutations in SLC30A10, a Mn efflux transporter. To explore the function of SLC30A10 in vitro, the current study used CRISPR/Cas9 gene editing to develop a stable SLC30A10 mutant Hep3B hepatoma cell line and collagenase perfusion in live mice to isolate primary hepatocytes deficient in Slc30a10. We also compared phenotypes of primary vs. non-primary cell lines to determine if they both serve as reliable in vitro models for the known physiological roles of SLC30A10. Mutant SLC30A10 Hep3B cells had increased Mn levels and decreased viability when exposed to excess Mn. Transport studies indicated a reduction of 54Mn import and export in mutant cells. While impaired 54Mn export was hypothesized given the essential role for SLC30A10 in cellular Mn export, impaired 54Mn import was unexpected. Whole genome sequencing did not identify any additional mutations in known Mn transporters in the mutant Hep3B mutant cell line. We then evaluated 54Mn transport in primary hepatocytes cultures isolated from genetically altered mice with varying liver Mn levels. Based on results from these experiments, we suggest that the effects of SLC30A10 deficiency on Mn homeostasis can be interrogated in vitro but only in specific types of cell lines.
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Affiliation(s)
- Milankumar Prajapati
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School, Brown University, Providence, RI, 02912, USA.
| | - Michael A Pettiglio
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School, Brown University, Providence, RI, 02912, USA.,Vor Biopharma, Cambridge, MA, USA
| | - Heather L Conboy
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School, Brown University, Providence, RI, 02912, USA
| | - Courtney J Mercadante
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School, Brown University, Providence, RI, 02912, USA.,Sanofi-Bioverativ, Waltham, MA, USA
| | - Shintaro Hojyo
- Deutsches Rheuma-Forschungszentrum Berlin, 10117, Berlin, Germany.,Division of Molecular Psychoimmunology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0815, Japan
| | - Toshiyuki Fukada
- Molecular and Cellular Physiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | - Thomas B Bartnikas
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School, Brown University, Providence, RI, 02912, USA
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13
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Styrpejko DJ, Cuajungco MP. Transmembrane 163 (TMEM163) Protein: A New Member of the Zinc Efflux Transporter Family. Biomedicines 2021; 9:biomedicines9020220. [PMID: 33670071 PMCID: PMC7926707 DOI: 10.3390/biomedicines9020220] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 12/27/2022] Open
Abstract
A growing body of evidence continues to demonstrate the vital roles that zinc and its transporters play on human health. The mammalian solute carrier 30 (SLC30) family, with ten current members, controls zinc efflux transport in cells. TMEM163, a recently reported zinc transporter, has similar characteristics in both predicted transmembrane domain structure and function to the cation diffusion facilitator (CDF) protein superfamily. This review discusses past and present data indicating that TMEM163 is a zinc binding protein that transports zinc in cells. We provide a brief background on TMEM163’s discovery, transport feature, protein interactome, and similarities, as well as differences, with known SLC30 (ZnT) protein family. We also examine recent reports that implicate TMEM163 directly or indirectly in various human diseases such as Parkinson’s disease, Mucolipidosis type IV and diabetes. Overall, the role of TMEM163 protein in zinc metabolism is beginning to be realized, and based on current evidence, we propose that it is likely a new CDF member belonging to mammalian SLC30 (ZnT) zinc efflux transporter proteins.
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Affiliation(s)
- Daniel J. Styrpejko
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
| | - Math P. Cuajungco
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
- Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA 92831, USA
- Correspondence:
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14
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Miller M, Mellul A, Braun M, Sherill-Rofe D, Cohen E, Shpilt Z, Unterman I, Braitbard O, Hochman J, Tshuva EY, Tabach Y. Titanium Tackles the Endoplasmic Reticulum: A First Genomic Study on a Titanium Anticancer Metallodrug. iScience 2020; 23:101262. [PMID: 32585595 PMCID: PMC7322074 DOI: 10.1016/j.isci.2020.101262] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/07/2020] [Accepted: 06/05/2020] [Indexed: 12/23/2022] Open
Abstract
PhenolaTi is an advanced non-toxic anticancer chemotherapy; this inert bis(phenolato)bis(alkoxo) Ti(IV) complex demonstrates the intriguing combination of high and wide efficacy with no detected toxicity in animals. Here we unravel the cellular pathways involved in its mechanism of action by a first genome study on Ti(IV)-treated cells, using an attuned RNA sequencing-based available technology. First, phenolaTi induced apoptosis and cell-cycle arrest at the G2/M phase in MCF7 cells. Second, the transcriptome of the treated cells was analyzed, identifying alterations in pathways relating to protein translation, DNA damage, and mitochondrial eruption. Unlike for common metallodrugs, electrophoresis assay showed no inhibition of DNA polymerase activity. Reduced in vitro cytotoxicity with added endoplasmic reticulum (ER) stress inhibitor supported the ER as a putative cellular target. Altogether, this paper reveals a distinct ER-related mechanism by the Ti(IV) anticancer coordination complex, paving the way for wider applicability of related techniques in mechanistic analyses of metallodrugs.
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Affiliation(s)
- Maya Miller
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Anna Mellul
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Maya Braun
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Dana Sherill-Rofe
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Emiliano Cohen
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Zohar Shpilt
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Irene Unterman
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Ori Braitbard
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Jacob Hochman
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Edit Y Tshuva
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Institute of Medical Research-Israel-Canada, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
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15
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Taylor CA, Tuschl K, Nicolai MM, Bornhorst J, Gubert P, Varão AM, Aschner M, Smith DR, Mukhopadhyay S. Maintaining Translational Relevance in Animal Models of Manganese Neurotoxicity. J Nutr 2020; 150:1360-1369. [PMID: 32211802 PMCID: PMC7269748 DOI: 10.1093/jn/nxaa066] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/06/2020] [Accepted: 02/25/2020] [Indexed: 12/14/2022] Open
Abstract
Manganese is an essential metal, but elevated brain Mn concentrations produce a parkinsonian-like movement disorder in adults and fine motor, attentional, cognitive, and intellectual deficits in children. Human Mn neurotoxicity occurs owing to elevated exposure from occupational or environmental sources, defective excretion (e.g., due to cirrhosis), or loss-of-function mutations in the Mn transporters solute carrier family 30 member 10 or solute carrier family 39 member 14. Animal models are essential to study Mn neurotoxicity, but in order to be translationally relevant, such models should utilize environmentally relevant Mn exposure regimens that reproduce changes in brain Mn concentrations and neurological function evident in human patients. Here, we provide guidelines for Mn exposure in mice, rats, nematodes, and zebrafish so that brain Mn concentrations and neurobehavioral sequelae remain directly relatable to the human phenotype.
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Affiliation(s)
- Cherish A Taylor
- Division of Pharmacology & Toxicology, College of Pharmacy, Institute for Cellular & Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Karin Tuschl
- Department of Cell and Developmental Biology, University College London, London, United Kingdom,Department of Developmental Neurobiology, King's College London, London, United Kingdom,Address correspondence to KT (e-mail: )
| | - Merle M Nicolai
- Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Julia Bornhorst
- Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Priscila Gubert
- Department of Biochemistry, Laboratory of Immunopathology Keizo Asami-LIKA, Federal University of Pernambuco, Recife, Pernambuco, Brazil,Postgraduate Program in Pure and Applied Chemistry, Federal University of Western Bahia, Barreiras, Bahia, Brazil
| | - Alexandre M Varão
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Donald R Smith
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy, Institute for Cellular & Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA,Address correspondence to SM (e-mail: )
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16
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Horning KJ, Joshi P, Nitin R, Balachandran RC, Yanko FM, Kim K, Christov P, Aschner M, Sulikowski GA, Weaver CD, Bowman AB. Identification of a selective manganese ionophore that enables nonlethal quantification of cellular manganese. J Biol Chem 2020; 295:3875-3890. [PMID: 32047113 PMCID: PMC7086026 DOI: 10.1074/jbc.ra119.009781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 02/11/2020] [Indexed: 01/14/2023] Open
Abstract
Available assays for measuring cellular manganese (Mn) levels require cell lysis, restricting longitudinal experiments and multiplexed outcome measures. Conducting a screen of small molecules known to alter cellular Mn levels, we report here that one of these chemicals induces rapid Mn efflux. We describe this activity and the development and implementation of an assay centered on this small molecule, named manganese-extracting small molecule (MESM). Using inductively-coupled plasma-MS, we validated that this assay, termed here "manganese-extracting small molecule estimation route" (MESMER), can accurately assess Mn in mammalian cells. Furthermore, we found evidence that MESM acts as a Mn-selective ionophore, and we observed that it has increased rates of Mn membrane transport, reduced cytotoxicity, and increased selectivity for Mn over calcium compared with two established Mn ionophores, calcimycin (A23187) and ionomycin. Finally, we applied MESMER to test whether prior Mn exposures subsequently affect cellular Mn levels. We found that cells receiving continuous, elevated extracellular Mn accumulate less Mn than cells receiving equally-elevated Mn for the first time for 24 h, indicating a compensatory cellular homeostatic response. Use of the MESMER assay versus a comparable detergent lysis-based assay, cellular Fura-2 Mn extraction assay, reduced the number of cells and materials required for performing a similar but cell lethality-based experiment to 25% of the normally required sample size. We conclude that MESMER can accurately quantify cellular Mn levels in two independent cells lines through an ionophore-based mechanism, maintaining cell viability and enabling longitudinal assessment within the same cultures.
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Affiliation(s)
- Kyle J. Horning
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232
| | - Piyush Joshi
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232
| | - Rachana Nitin
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232
| | | | - Frank M. Yanko
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907
| | - Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235
| | - Plamen Christov
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Gary A. Sulikowski
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235,Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37212
| | - C. David Weaver
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235,Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37212
| | - Aaron B. Bowman
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232,School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, To whom correspondence should be addressed:
Purdue University, 550 Stadium Mall Dr., HAMP 1173A, West Lafayette, IN 47907-2051. E-mail:
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17
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Li D, Mukhopadhyay S. Functional analyses of the UDP-galactose transporter SLC35A2 using the binding of bacterial Shiga toxins as a novel activity assay. Glycobiology 2020; 29:490-503. [PMID: 30834435 DOI: 10.1093/glycob/cwz016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/17/2019] [Accepted: 02/28/2019] [Indexed: 01/13/2023] Open
Abstract
SLC35A2 transports UDP-galactose from the cytosol to the lumen of the Golgi apparatus and endoplasmic reticulum for glycosylation. Mutations in SLC35A2 induce a congenital disorder of glycosylation. Despite the biomedical relevance, mechanisms of transport via SLC35A2 and the impact of disease-associated mutations on activity are unclear. To address these issues, we generated a predicted structure of SLC35A2 and assayed for the effects of a set of structural and disease-associated mutations. Activity assays were performed using a rescue approach in ΔSLC35A2 cells and took advantage of the fact that SLC35A2 is required for expression of the glycosphingolipid globotriaosylceramide (Gb3), the cell surface receptor for Shiga toxin 1 (STx1) and 2 (STx2). The N- and C-terminal cytoplasmic loops of SLC35A2 were dispensable for activity, but two critical glycine (Gly-202 and Gly-214) and lysine (Lys-78 and Lys-297) residues in transmembrane segments were required. Residues corresponding to Gly-202 and Gly-214 in the related transporter SLC35A1 form a substrate-translocating channel, suggesting that a similar mechanism may be involved in SLC35A2. Among the eight disease-associated mutations tested, SLC35A2 function was completely inhibited by two (S213F and G282R) and partially inhibited by three (R55L, G266V, and S304P), providing a straight-forward mechanism of disease. Interestingly, the remaining three (V331I, V258M, and Y267C) did not impact SLC35A2 function, suggesting that complexities beyond loss of transporter activity may underlie disease due to these mutations. Overall, our results provide new insights into the mechanisms of transport of SLC35A2 and improve understanding of the relationship between SLC35A2 mutations and disease.
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Affiliation(s)
- Danyang Li
- Division of Pharmacology & Toxicology, College of Pharmacy, Institute for Cellular & Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Somshuvra Mukhopadhyay
- Division of Pharmacology & Toxicology, College of Pharmacy, Institute for Cellular & Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
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18
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Zhao M, Zhou B. A distinctive sequence motif in the fourth transmembrane domain confers ZIP13 iron function in Drosophila melanogaster. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118607. [PMID: 31733261 DOI: 10.1016/j.bbamcr.2019.118607] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/04/2019] [Accepted: 11/11/2019] [Indexed: 01/17/2023]
Abstract
The zinc/iron permease (ZIP/SLC39A) family plays an important role in metal ion transport and is essential for diverse physiological processes. Members of the ZIP family function primarily in the influx of transition metal ions zinc and iron, into cytoplasm from extracellular space or intracellular organelles. The molecular determinants defining metal ion selectivity among ZIP family members remain unclear. Specifically, we reported before that the Drosophila ZIP family member ZIP13 (dZIP13), functions as an iron exporter and was responsible for pumping iron into the secretory pathway. ZIP13 protein is unique in that it differs from the other LIV-1 subfamily members at transmembrane domain IV (TM4), wherein relative positions of the conserved H and D residues in the HNXXD sequence motif are switched, generating a DNXXH motif. In this study, we undertook an in vivo approach to explore the significance of this D/H exchange. Comparative functional analysis of mutants revealed that the relative positions of D and H are critical for the physiological roles of dZIP13 and its close homologue dZIP7. Swapping D/H position of this DNXXH sequence in dZIP13 resulted in loss of iron activity; normal dZIP13 could not complement dZIP7 loss, but swapping the two relative amino acid positions D and H in dZIP13 was sufficient to make it functionally analogous to its close homologue dZIP7. This work provides the first in vivo functional analysis of a structural motif required to differentiate different transporting functions of ZIPs.
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Affiliation(s)
- Mengran Zhao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bing Zhou
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China.
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19
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Lehvy AI, Horev G, Golan Y, Glaser F, Shammai Y, Assaraf YG. Alterations in ZnT1 expression and function lead to impaired intracellular zinc homeostasis in cancer. Cell Death Discov 2019; 5:144. [PMID: 31728210 PMCID: PMC6851190 DOI: 10.1038/s41420-019-0224-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 08/26/2019] [Accepted: 10/01/2019] [Indexed: 02/08/2023] Open
Abstract
Zinc is vital for the structure and function of ~3000 human proteins and hence plays key physiological roles. Consequently, impaired zinc homeostasis is associated with various human diseases including cancer. Intracellular zinc levels are tightly regulated by two families of zinc transporters: ZIPs and ZnTs; ZIPs import zinc into the cytosol from the extracellular milieu, or from the lumen of organelles into the cytoplasm. In contrast, the vast majority of ZnTs compartmentalize zinc within organelles, whereas the ubiquitously expressed ZnT1 is the sole zinc exporter. Herein, we explored the hypothesis that qualitative and quantitative alterations in ZnT1 activity impair cellular zinc homeostasis in cancer. Towards this end, we first used bioinformatics to analyze inactivating mutations in ZIPs and ZNTs, catalogued in the COSMIC and gnomAD databases, representing tumor specimens and healthy population controls, respectively. ZnT1, ZnT10, ZIP8, and ZIP10 showed extremely high rates of loss of function mutations in cancer as compared to healthy controls. Analysis of the putative functional impact of missense mutations in ZnT1-ZnT10 and ZIP1-ZIP14, using homologous protein alignment and structural predictions, revealed that ZnT1 displays a markedly increased frequency of predicted functionally deleterious mutations in malignant tumors, as compared to a healthy population. Furthermore, examination of ZnT1 expression in 30 cancer types in the TCGA database revealed five tumor types with significant ZnT1 overexpression, which predicted dismal prognosis for cancer patient survival. Novel functional zinc transport assays, which allowed for the indirect measurement of cytosolic zinc levels, established that wild type ZnT1 overexpression results in low intracellular zinc levels. In contrast, overexpression of predicted deleterious ZnT1 missense mutations did not reduce intracellular zinc levels, validating eight missense mutations as loss of function (LoF) mutations. Thus, alterations in ZnT1 expression and LoF mutations in ZnT1 provide a molecular mechanism for impaired zinc homeostasis in cancer formation and/or progression.
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Affiliation(s)
- Adrian Israel Lehvy
- 1The Fred Wyszkowski Cancer Research, Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Guy Horev
- 2Bioinformatics Knowledge Unit, The Lorry, I. Lokey Interdisciplinary Center for Life, Sciences and Engineering, Technion-Israel, Institute of Technology, Haifa, Israel
| | - Yarden Golan
- 1The Fred Wyszkowski Cancer Research, Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Fabian Glaser
- 2Bioinformatics Knowledge Unit, The Lorry, I. Lokey Interdisciplinary Center for Life, Sciences and Engineering, Technion-Israel, Institute of Technology, Haifa, Israel
| | - Yael Shammai
- 1The Fred Wyszkowski Cancer Research, Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yehuda Gérard Assaraf
- 1The Fred Wyszkowski Cancer Research, Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
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20
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Taylor CA, Hutchens S, Liu C, Jursa T, Shawlot W, Aschner M, Smith DR, Mukhopadhyay S. SLC30A10 transporter in the digestive system regulates brain manganese under basal conditions while brain SLC30A10 protects against neurotoxicity. J Biol Chem 2018; 294:1860-1876. [PMID: 30559290 DOI: 10.1074/jbc.ra118.005628] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/12/2018] [Indexed: 01/18/2023] Open
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.
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Affiliation(s)
- Cherish A Taylor
- From the Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience and
| | - Steven Hutchens
- From the Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience and
| | - Chunyi Liu
- From the Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience and
| | - Thomas Jursa
- the Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California 95064, and
| | - William Shawlot
- the Mouse Genetic Engineering Facility, University of Texas, Austin, Texas 78712
| | - Michael Aschner
- the Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Donald R Smith
- the Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California 95064, and
| | - Somshuvra Mukhopadhyay
- From the Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience and
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21
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Golan Y, Alhadeff R, Glaser F, Ganoth A, Warshel A, Assaraf YG. Demonstrating aspects of multiscale modeling by studying the permeation pathway of the human ZnT2 zinc transporter. PLoS Comput Biol 2018; 14:e1006503. [PMID: 30388104 PMCID: PMC6241132 DOI: 10.1371/journal.pcbi.1006503] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/14/2018] [Accepted: 09/11/2018] [Indexed: 11/18/2022] Open
Abstract
Multiscale modeling provides a very powerful means of studying complex biological systems. An important component of this strategy involves coarse-grained (CG) simplifications of regions of the system, which allow effective exploration of complex systems. Here we studied aspects of CG modeling of the human zinc transporter ZnT2. Zinc is an essential trace element with 10% of the proteins in the human proteome capable of zinc binding. Thus, zinc deficiency or impairment of zinc homeostasis disrupt key cellular functions. Mammalian zinc transport proceeds via two transporter families: ZnT and ZIP; however, little is known about the zinc permeation pathway through these transporters. As a step towards this end, we herein undertook comprehensive computational analyses employing multiscale techniques, focusing on the human zinc transporter ZnT2 and its bacterial homologue, YiiP. Energy calculations revealed a favorable pathway for zinc translocation via alternating access. We then identified key residues presumably involved in the passage of zinc ions through ZnT2 and YiiP, and functionally validated their role in zinc transport using site-directed mutagenesis of ZnT2 residues. Finally, we use a CG Monte Carlo simulation approach to sample the transition between the inward-facing and the outward-facing states. We present our structural models of the inward- and outward-facing conformations of ZnT2 as a blueprint prototype of the transporter conformations, including the putative permeation pathway and participating residues. The insights gained from this study may facilitate the delineation of the pathways of other zinc transporters, laying the foundations for the molecular basis underlying ion permeation. This may possibly facilitate the development of therapeutic interventions in pathological states associated with zinc deficiency and other disorders based on loss-of-function mutations in solute carriers.
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Affiliation(s)
- Yarden Golan
- The Fred Wyszkowski Cancer Research Laboratory, Dept. of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Raphael Alhadeff
- Department of Chemistry, University of Southern California, Los Angeles, CA, United States of America
| | - Fabian Glaser
- Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Assaf Ganoth
- The Interdisciplinary Center (IDC), Herzliya, Israel
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, Los Angeles, CA, United States of America
- * E-mail: (AW); (YGA)
| | - Yehuda G. Assaraf
- The Fred Wyszkowski Cancer Research Laboratory, Dept. of Biology, Technion-Israel Institute of Technology, Haifa, Israel
- * E-mail: (AW); (YGA)
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