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Azzollini L, Prete DD, Wolf G, Klimek C, Saggioro M, Ricci F, Christodoulaki E, Wiedmer T, Ingles-Prieto A, Superti-Furga G, Scarabottolo L. Development of a live cell assay for the zinc transporter ZnT8. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2024; 29:100166. [PMID: 38848895 DOI: 10.1016/j.slasd.2024.100166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/27/2024] [Accepted: 06/04/2024] [Indexed: 06/09/2024]
Abstract
Zinc is an essential trace element that is involved in many biological processes and in cellular homeostasis. In pancreatic β-cells, zinc is crucial for the synthesis, processing, and secretion of insulin, which plays a key role in glucose homeostasis and which deficiency is the cause of diabetes. The accumulation of zinc in pancreatic cells is regulated by the solute carrier transporter SLC30A8 (or Zinc Transporter 8, ZnT8), which transports zinc from cytoplasm in intracellular vesicles. Allelic variants of SLC30A8 gene have been linked to diabetes. Given the physiological intracellular localization of SLC30A8 in pancreatic β-cells and the ubiquitous endogenous expression of other Zinc transporters in different cell lines that could be used as cellular model for SLC30A8 recombinant over-expression, it is challenging to develop a functional assay to measure SLC30A8 activity. To achieve this goal, we have firstly generated a HEK293 cell line stably overexpressing SLC30A8, where the over-expression favors the partial localization of SLC30A8 on the plasma membrane. Then, we used the combination of this cell model, commercial FluoZin-3 cell permeant zinc dye and live cell imaging approach to follow zinc flux across SLC30A8 over-expressed on plasma membrane, thus developing a novel functional imaging- based assay specific for SLC30A8. Our novel approach can be further explored and optimized, paving the way for future small molecule medium-throughput screening.
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Affiliation(s)
- Lucia Azzollini
- Axxam SpA, Openzone, Via Meucci 3 20091 Bresso, Milan, Italy.
| | | | - Gernot Wolf
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Christoph Klimek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Mattia Saggioro
- Axxam SpA, Openzone, Via Meucci 3 20091 Bresso, Milan, Italy
| | - Fernanda Ricci
- Axxam SpA, Openzone, Via Meucci 3 20091 Bresso, Milan, Italy
| | - Eirini Christodoulaki
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Tabea Wiedmer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Alvaro Ingles-Prieto
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria; Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Bi SS, Talukder M, Jin HT, Lv MW, Ge J, Zhang C, Li JL. Cadmium Through Disturbing MTF1-Mediated Metal Response Induced Cerebellar Injury. Neurotox Res 2022; 40:1127-1137. [PMID: 35895249 PMCID: PMC9326427 DOI: 10.1007/s12640-022-00474-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/05/2022] [Accepted: 01/11/2022] [Indexed: 11/29/2022]
Abstract
Cadmium (Cd) is a toxic environmental contaminant, which bio-accumulate in animals through the food chain. Cerebellum is one of the primary target organs for Cd exposure. In this study, we established a chronic Cd exposure model; 60 chickens were treated with Cd (0 mg/kg, 35 mg/kg, 70 mg/kg) for 90 days. Clinical manifestations indicated that the chicken was depressed and has unstable gait under Cd exposure. Histopathological results indicated that Cd induced neuronal shrunken and indistinct nucleoli, and the number of Purkinje cells decreased significantly. Cerebellar metal contents were analyzed by ICP-MS. We found that Cd caused Cd and Cu accumulation and decreased the content of Se, Fe, and Zn, suggesting that Cd disturbed metal homeostasis. Besides, Cd treatment group also showed high levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) content and inhibited selenoprotein transcriptome, suggesting that Cd exposure resulted in oxidative stress. Notably, low-dose Cd exposure activated MTF1 mRNA and protein expression and its target metal-responsive genes, including MT1, MT2, DMT1, ZIP8, ZIP10, TF, and ATP7B which indicate cellular adaptive response against Cd-induced damage. On the other hand, 70 mg/kg Cd downregulated MTF1-mediated metal response, which was involved in Cd-induced cerebellar injury in chicken. In conclusion, our data demonstrated that molecular mechanisms are associated with Cd-induced cerebellar injury due to disturbing MTF1-mediated metal response.
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Affiliation(s)
- Shao-Shuai Bi
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China.,College of Biological and Pharmaceutical Engineering, West Anhui University, Lu'an , 237012, People's Republic of China
| | - Milton Talukder
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China.,Faculty of Animal Science and Veterinary Medicine, Department of Physiology and Pharmacology, Patuakhali Science and Technology University, Barishal, 8210, Bangladesh
| | - Hai-Tao Jin
- Quality and Safety Institute of Agricultural Products, Heilongjiang Academy of Agricultural Sciences, Harbin, 150010, People's Republic of China
| | - Mei-Wei Lv
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Jing Ge
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Cong Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China.,College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, People's Republic of China
| | - Jin-Long Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China. .,Key Laboratory of the Provincial Education, Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin, 150030, People's Republic of China. .,Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
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Wong WP, Wang JC, Meyers MS, Wang NJ, Sponenburg RA, Allen NB, Edwards JE, El Muayed M. A novel chronic in vivo oral cadmium exposure-washout mouse model for studying cadmium toxicity and complex diabetogenic effects. Toxicol Appl Pharmacol 2022; 447:116057. [PMID: 35550884 PMCID: PMC9854171 DOI: 10.1016/j.taap.2022.116057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 01/25/2023]
Abstract
Type II diabetes mellitus (T2DM) is characterized by insulin resistance, β-cell dysfunction and hyperglycemia. In addition to well known risk factors such as lifestyle and genetic risk score, accumulation of environmental toxicants in organs relevant to glucose metabolism is increasingly recognized as additional risk factors for T2DM. Here, we describe the development of an in vivo oral cadmium (Cd) exposure model. It was shown that oral Cd exposure in drinking water followed by washout and high fat diet (HFD) in C57BL/6N mice results in islet Cd bioaccumulation comparable to that found in native human islets while mitigating the anorexic effects of Cd to achieve the same weight gain required to induce insulin resistance as in Cd naïve control mice. Inter individual variation in plasma glucose and insulin levels as well as islet Cd bioaccumulation was observed in both female and male mice. Regression analysis showed an inverse correlation between islet Cd level and plasma insulin following a glucose challenge in males but not in females. This finding highlights the need to account for inter individual target tissue Cd concentrations when interpreting results from in vivo Cd exposure models. No effect of Cd on insulin secretion was observed in islets ex vivo, highlighting differences between in vivo and ex vivo cadmium exposure models. In summary, our oral in vivo Cd exposure-washout with HFD model resulted in islet Cd bioaccumulation that is relevant in the context of environmental cadmium exposure in humans. Here, we showed that islet Cd bioaccumulation is associated with complex cadmium-mediated changes in glucose clearance and β-cell function. The model described here will serve as a useful tool to further examine the relationship between Cd exposure, islet Cd bioaccumulation, dysglycemia and their underlying mechanisms.
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Affiliation(s)
- Winifred P.S. Wong
- Division of Endocrinology, Metabolism and Molecular
Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611,
USA
| | - Janice C. Wang
- Division of Endocrinology, Metabolism and Molecular
Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611,
USA
| | - Matthew S. Meyers
- Division of Endocrinology, Metabolism and Molecular
Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611,
USA
| | - Nathan J. Wang
- Division of Endocrinology, Metabolism and Molecular
Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611,
USA
| | - Rebecca A. Sponenburg
- Quantitative Bio-element Imaging Centre, Chemistry of Life
Processes, Northwestern University, Evanston, IL 60208, USA
| | - Norrina B. Allen
- Institute for Public Health and Medicine, Center for
Epidemiology and Population Health, Feinberg School of Medicine, Northwestern
University, Chicago, IL 60611, USA
| | - Joshua E. Edwards
- College of Graduate Studies, Midwestern University, Downers
Grove, IL 60515, USA
| | - Malek El Muayed
- Division of Endocrinology, Metabolism and Molecular
Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611,
USA.,Corresponding author.
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LncRNA-Associated Genetic Etiologies Are Shared between Type 2 Diabetes and Cancers in the UAE Population. Cancers (Basel) 2022; 14:cancers14143313. [PMID: 35884374 PMCID: PMC9313416 DOI: 10.3390/cancers14143313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/22/2022] [Accepted: 05/06/2022] [Indexed: 12/13/2022] Open
Abstract
Numerous epidemiological studies place patients with T2D at a higher risk for cancer. Many risk factors, such as obesity, ageing, poor diet and low physical activity, are shared between T2D and cancer; however, the biological mechanisms linking the two diseases remain largely unknown. The advent of genome wide association studies (GWAS) revealed large numbers of genetic variants associated with both T2D and cancer. Most significant disease-associated variants reside in non-coding regions of the genome. Several studies show that single nucleotide polymorphisms (SNPs) at or near long non-coding RNA (lncRNA) genes may impact the susceptibility to T2D and cancer. Therefore, the identification of genetic variants predisposing individuals to both T2D and cancer may help explain the increased risk of cancer in T2D patients. We aim to investigate whether lncRNA genetic variants with significant diabetes and cancer associations overlap in the UAE population. We first performed an annotation-based analysis of UAE T2D GWAS, confirming the high prevalence of variants at or near non-coding RNA genes. We then explored whether these T2D SNPs in lncRNAs were relevant to cancer. We highlighted six non-coding genetic variants, jointly reaching statistical significance in T2D and cancer, implicating a shared genetic architecture between the two diseases in the UAE population.
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He Z, Yin G, Li QQ, Zeng Q, Duan J. Diabetes Mellitus Causes Male Reproductive Dysfunction: A Review of the Evidence and Mechanisms. In Vivo 2021; 35:2503-2511. [PMID: 34410936 DOI: 10.21873/invivo.12531] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/09/2021] [Accepted: 06/15/2021] [Indexed: 01/05/2023]
Abstract
The metabolic disorders caused by diabetes can lead to various complications, including dysfunction of the male reproductive system. In patients with diabetes, long-term hyperglycemia results in diabetic vascular neuropathy, oxidative stress injury, abnormal zinc metabolism, and insulin resistance syndrome. In addition, insulin deficiency and resistance in diabetes can damage the hypothalamus, pituitary gland, gonads, and perigonads. This can reduce the secretion of sex hormones including gonadotropin-releasing hormone, follicle stimulating hormone, luteinizing hormone, and testosterone, and can lead to testicular atrophy, stromal cell atrophy, seminiferous tubule damage, spermatogenic cell damage, and other structural injuries of the male reproductive organs. These actions can affect male fertility and reproductive health. Herein, we review studies that report a causative role of diabetes in male reproductive function. We also discuss the evidence-based mechanisms involved in the processes of diabetes-related male sexual and reproductive dysfunction as well as the progress in treatment.
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Affiliation(s)
- Zubin He
- 924 Hospital of PLA Joint Logistic Support Force, Guilin, P.R. China
| | - Guochao Yin
- Guilin Rehabilitation and Recuperation Center, Guilin, P.R. China
| | - Qingdi Quentin Li
- Scientific Review Branch, Division of Extramural Research and Training, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, U.S.A
| | - Qiongfang Zeng
- 924 Hospital of PLA Joint Logistic Support Force, Guilin, P.R. China
| | - Jinliang Duan
- 924 Hospital of PLA Joint Logistic Support Force, Guilin, P.R. China;
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Barragán-Álvarez CP, Padilla-Camberos E, Díaz NF, Cota-Coronado A, Hernández-Jiménez C, Bravo-Reyna CC, Díaz-Martínez NE. Loss of Znt8 function in diabetes mellitus: risk or benefit? Mol Cell Biochem 2021; 476:2703-2718. [PMID: 33666829 DOI: 10.1007/s11010-021-04114-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/18/2021] [Indexed: 12/13/2022]
Abstract
The zinc transporter 8 (ZnT8) plays an essential role in zinc homeostasis inside pancreatic β cells, its function is related to the stabilization of insulin hexameric form. Genome-wide association studies (GWAS) have established a positive and negative relationship of ZnT8 variants with type 2 diabetes mellitus (T2DM), exposing a dual and controversial role. The first hypotheses about its role in T2DM indicated a higher risk of developing T2DM for loss of function; nevertheless, recent GWAS of ZnT8 loss-of-function mutations in humans have shown protection against T2DM. With regard to the ZnT8 role in T2DM, most studies have focused on rodent models and common high-risk variants; however, considerable differences between human and rodent models have been found and the new approaches have included lower-frequency variants as a tool to clarify gene functions, allowing a better understanding of the disease and offering possible therapeutic targets. Therefore, this review will discuss the physiological effects of the ZnT8 variants associated with a major and lower risk of T2DM, emphasizing the low- and rare-frequency variants.
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Affiliation(s)
- Carla P Barragán-Álvarez
- Biotecnología Médica y Farmacéutica, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico
| | - Eduardo Padilla-Camberos
- Biotecnología Médica y Farmacéutica, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico
| | - Nestor F Díaz
- Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología, Mexico City, Mexico
| | - Agustín Cota-Coronado
- Biotecnología Médica y Farmacéutica, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico
| | - Claudia Hernández-Jiménez
- Departamento de Cirugía Experimental, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Carlos C Bravo-Reyna
- Departamento de Cirugía Experimental, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Nestor E Díaz-Martínez
- Biotecnología Médica y Farmacéutica, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Guadalajara, Mexico.
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7
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Zhao T, Huang Q, Su Y, Sun W, Huang Q, Wei W. Zinc and its regulators in pancreas. Inflammopharmacology 2019; 27:453-464. [PMID: 30756223 DOI: 10.1007/s10787-019-00573-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/02/2019] [Indexed: 12/12/2022]
Abstract
Studies have demonstrated that susceptibility to type 2 diabetes (T2D) is influenced by common polymorphism in the zinc transporter 8 gene SLC30A8, providing novel insight into the role of zinc in diabetes. Intriguingly, zinc participates in every step of the process, including insulin synthesis, crystallization, storage, secretion and signaling. Zinc deficiency or overload is associated with various disorders, such as diabetes, cardiovascular disease and obesity. Zinc supplementation is considered as an effective means of treating or preventing T2D in people with certain SLC30A8 genotypes. Three important protein families-zinc transporters (ZnTs), zinc importers (ZiPs) and metallothionein (MT)-participate in maintaining zinc homeostasis. Here, we review research on the physiological characteristics of zinc and its role in the pancreas and homeostasis regulation mechanisms, along with the latest research on the structure and function of ZnT/ZiP and MT. In addition, we summarize the advancements in research on SLC30A8 gene polymorphism in search of a mechanism to explain the relationship between the R risk allele and zinc transporter activity.
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Affiliation(s)
- Tianjiao Zhao
- Key Laboratory of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei, 230032, China
| | - Qiongfang Huang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei, 230032, China
| | - Yangni Su
- Key Laboratory of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei, 230032, China
| | - Wuyi Sun
- Key Laboratory of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei, 230032, China
| | - Qiong Huang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei, 230032, China.
| | - Wei Wei
- Key Laboratory of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei, 230032, China.
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Cruz KJC, de Oliveira ARS, Morais JBS, Severo JS, Mendes PMV, de Sousa Melo SR, de Sousa GS, Marreiro DDN. Zinc and Insulin Resistance: Biochemical and Molecular Aspects. Biol Trace Elem Res 2018; 186:407-412. [PMID: 29564656 DOI: 10.1007/s12011-018-1308-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 03/14/2018] [Indexed: 01/31/2023]
Abstract
Studies have shown the participation of minerals in mechanisms involved in the pathogenesis of insulin resistance. Zinc, in particular, seems to play an important role in the secretion and action of this hormone. Therefore, the aim of this review is to understand the role of zinc in increasing insulin sensitivity. We conducted a search of articles published in the PubMed and ScienceDirect database selected from March 2016 to February 2018, using the keywords "zinc," "insulin," "insulin resistance," "insulin sensitivity," and "supplementation." Following the eligibility criteria were selected 53 articles. The scientific evidences presented in this review show the importance of zinc and their carrier proteins in the synthesis and secretion of insulin, as well as in the signaling pathway of action of this hormone. Zinc deficiency is associated with glucose intolerance and insulin resistance; however, the effectiveness of the intervention with the zinc supplementation is still inconclusive.
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Affiliation(s)
- Kyria Jayanne Clímaco Cruz
- Department of Nutrition, Federal University of Piauí, Ministro Petrônio Portella Campus, Ininga, Teresina, Piauí, Brazil
| | - Ana Raquel Soares de Oliveira
- Department of Nutrition, Federal University of Piauí, Ministro Petrônio Portella Campus, Ininga, Teresina, Piauí, Brazil
| | - Jennifer Beatriz Silva Morais
- Department of Nutrition, Federal University of Piauí, Ministro Petrônio Portella Campus, Ininga, Teresina, Piauí, Brazil
| | - Juliana Soares Severo
- Department of Nutrition, Federal University of Piauí, Ministro Petrônio Portella Campus, Ininga, Teresina, Piauí, Brazil
| | - Priscyla Maria Vieira Mendes
- Department of Nutrition, Federal University of Piauí, Ministro Petrônio Portella Campus, Ininga, Teresina, Piauí, Brazil
| | | | | | - Dilina do Nascimento Marreiro
- Department of Nutrition, Federal University of Piauí, Ministro Petrônio Portella Campus, Ininga, Teresina, Piauí, Brazil.
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Lawson R, Maret W, Hogstrand C. Prolonged stimulation of insulin release from MIN6 cells causes zinc depletion and loss of β-cell markers. J Trace Elem Med Biol 2018; 49:51-59. [PMID: 29895372 DOI: 10.1016/j.jtemb.2018.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/19/2018] [Accepted: 04/18/2018] [Indexed: 11/17/2022]
Abstract
Zinc is integral for the normal function of pancreatic β-cells in glycaemic control. Large amounts of zinc are secreted from β-cells following insulin exocytosis and regulated replenishment is required, which is thought to be mediated by the ZIP family of zinc importer proteins. Within Type 2 Diabetic patients, β-cells are stressed through prolonged stimulation by hyperglycaemia and this is thought to be a major factor contributing to loss of β-cell identity and mass. However, the consequences for the β-cell zinc status remain largely unexplored. We used inductively coupled plasma mass spectrometry (ICP-MS) to show that 24 h treatment of MIN6 cells with potassium chloride, mimicking hyperglycaemic stimulation, reduces the total cellular zinc content 2.8-fold, and qPCR to show an increase in mRNA expression for metallothioneins (Mt1 and Mt2) following 4 and 24 h of stimulation, suggestive of an early rise in cytosolic zinc. To determine which ZIP paralogues may be responsible for zinc replenishment, we used immunocytochemistry, Western blot and qPCR to demonstrate initial ZIP1 protein upregulation proceeded by downregulation of mRNA coding for ZIP1, ZIP6, ZIP7 and ZIP14. To assign a biological significance to the decreased total cellular zinc content, we assessed expression of key β-cell markers to show downregulation of mRNA for MafA, Mnx-1, Nkx2.2 and Pax6. Our data suggest hyperglycaemia-induced zinc depletion may contribute to loss of β-cell markers and promote β-cell dedifferentiation through disrupting expression of key transcription factors.
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Affiliation(s)
- Rebecca Lawson
- King's College London, Faculty of Life Sciences and Medicine, School of Life Course Sciences, Metal Metabolism Group, 150 Stamford St., London SE1 9NH, UK.
| | - Wolfgang Maret
- King's College London, Faculty of Life Sciences and Medicine, School of Life Course Sciences, Metal Metabolism Group, 150 Stamford St., London SE1 9NH, UK.
| | - Christer Hogstrand
- King's College London, Faculty of Life Sciences and Medicine, School of Life Course Sciences, Metal Metabolism Group, 150 Stamford St., London SE1 9NH, UK.
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