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Hagmeyer S, Cristóvão JS, Mulvihill JJE, Boeckers TM, Gomes CM, Grabrucker AM. Zinc Binding to S100B Affords Regulation of Trace Metal Homeostasis and Excitotoxicity in the Brain. Front Mol Neurosci 2018; 10:456. [PMID: 29386995 PMCID: PMC5776125 DOI: 10.3389/fnmol.2017.00456] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/26/2017] [Indexed: 12/16/2022] Open
Abstract
Neuronal metal ions such as zinc are essential for brain function. In particular synaptic processes are tightly related to metal and protein homeostasis, for example through extracellular metal-binding proteins. One such protein is neuronal S100B, a calcium and zinc binding damage-associated molecular pattern (DAMP), whose chronic upregulation is associated with aging, Alzheimer’s disease (AD), motor neuron disease and traumatic brain injury (TBI). Despite gained insights on the structure of S100B, it remains unclear how its calcium and zinc binding properties regulate its function on cellular level. Here we report a novel role of S100B in trace metal homeostasis, in particular the regulation of zinc levels in the brain. Our results show that S100B at increased extracellular levels is not toxic, persists at high levels, and is taken up into neurons, as shown by cell culture and biochemical analysis. Combining protein bioimaging and zinc quantitation, along with a zinc-binding impaired S100B variant, we conclude that S100B effectively scavenges zinc ions through specific binding, resulting in a redistribution of the intracellular zinc pool. Our results indicate that scavenging of zinc by increased levels of S100B affects calcium levels in vitro. Thereby S100B is able to mediate the cross talk between calcium and zinc homeostasis. Further, we investigated a possible new neuro-protective role of S100B in excitotoxicity via its effects on calcium and zinc homeostasis. Exposure of cells to zinc-S100B but not the zinc-binding impaired S100B results in an inhibition of excitotoxicity. We conclude that in addition to its known functions, S100B acts as sensor and regulator of elevated zinc levels in the brain and this metal-buffering activity is tied to a neuroprotective role.
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Affiliation(s)
- Simone Hagmeyer
- WG Molecular Analysis of Synaptopathies, Department of Neurology, Neurocenter of Ulm University, Ulm, Germany.,Cellular Neurobiology and Neuro-Nanotechnology Lab, Department of Biological Sciences, University of Limerick, Limerick, Ireland.,Bernal Institute, University of Limerick, Limerick, Ireland
| | - Joana S Cristóvão
- Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - John J E Mulvihill
- Bernal Institute, University of Limerick, Limerick, Ireland.,Health Research Institute (HRI), University of Limerick, Limerick, Ireland
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Cláudio M Gomes
- Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Andreas M Grabrucker
- Cellular Neurobiology and Neuro-Nanotechnology Lab, Department of Biological Sciences, University of Limerick, Limerick, Ireland.,Bernal Institute, University of Limerick, Limerick, Ireland.,Health Research Institute (HRI), University of Limerick, Limerick, Ireland
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Bluhm B, Laffer B, Hirnet D, Rothermundt M, Ambree O, Lohr C. Normal cerebellar development in S100B-deficient mice. THE CEREBELLUM 2015; 14:119-27. [PMID: 25342137 DOI: 10.1007/s12311-014-0606-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The calcium-binding protein S100B has been shown to support neuron proliferation, migration and neurite growth in vitro, while the significance of S100B for neuronal development in vivo is controversial. We have investigated the effect of S100B deficiency on cerebellar development in S100B knockout mice at an age of 5 and 10 days after birth (P5 and P10). This time range covers important developmental steps in the cerebellum such as granule cell proliferation and migration, as well as dendritic growth of Purkinje cells. Bergmann glial cells contain a particularly high concentration of S100B and serve as scaffold for both migrating granule cells and growing Purkinje cell dendrites. This renders the postnatal cerebellum ideal as a model system to study the importance of S100B for glial and neuronal development. We measured the length of Bergmann glial processes, the width of the external granule cell layer as a measure of granule cell proliferation, the decrease in width of the external granule cell layer between P5 and P10 as a measure of granule cell migration, and the length of Purkinje cell dendrites in wild-type and S100B knockout mice. None of these parameters showed significant differences between wild-type and knockout mice. In addition, wild-type and knockout mice performed equally in locomotor behaviour tests. The results indicate that S100B-deficient mice have normal development of the cerebellum and no severe impairment of motor function.
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Affiliation(s)
- Björn Bluhm
- Division of Neurophysiology, Biocenter Grindel, Martin-Luther-King-Pl. 3, D-20146, Hamburg, Germany
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Davydov DM, Lobanov AV, Morozov SG, Gribova IE, Murashev AN. Neurodevelopment and phenotype-modulating functions of S100B protein: a pilot study. Physiol Behav 2015; 140:188-96. [PMID: 25543091 DOI: 10.1016/j.physbeh.2014.12.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 12/21/2014] [Accepted: 12/22/2014] [Indexed: 12/13/2022]
Abstract
The importance of certain neurotrophic proteins found in maternal blood and milk for breastfed infants has remained ambiguous. This study was conducted to present evidence of the impact of an induced deficit of active S100B protein on neonate development. Newborn mice from two groups of mothers, immunized or sham-immunized against S100B, were subjected to various behavioral tests, and the development of their morphological characteristics was recorded from birth until weaning. Morphological problems, including weight gain and fur coating, a delay in the maturation of neurobehavioral systems and a deficit in neuromotor functions, including visual abilities, somato-sensory and posture reactions, muscular strength, locomotion, and fear/orienting processes, were observed in pups of immunized mothers. The S100B protein of external or internal origin in infants may be considered to be a specific factor that determines neuro- and morphological development and a risk-avoidance ('homeward-bent' or fearful) phenotype. The suppression of activity of the S100B protein results in a slower neonatal development and the formation of a risk-tolerant (fearless) phenotype of the offspring. This study thus considers the mechanism of neuroplastic regulation on the extent of sensation-seeking or risk-taking (homeless-like or fearless) and sensation- or risk-avoidance (home-bound or fearful) features in individual phenotypes.
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Affiliation(s)
- D M Davydov
- Sholokhov Moscow State University for the Humanities, The Russian Institute for Advanced Study and Institute of Neurosciences and Cognitive Research, Verkhnyaya Radishevskaya 16-18, Moscow 109240, Russia; Institute of General Pathology and Pathophysiology RAMS, Baltiyskaia ul. 8, Moscow 125315, Russia.
| | - A V Lobanov
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Pushchino, Moscow Region 142290, Russia.
| | - S G Morozov
- Institute of General Pathology and Pathophysiology RAMS, Baltiyskaia ul. 8, Moscow 125315, Russia.
| | - I E Gribova
- Institute of General Pathology and Pathophysiology RAMS, Baltiyskaia ul. 8, Moscow 125315, Russia.
| | - A N Murashev
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Pushchino, Moscow Region 142290, Russia.
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Abstract
S100 proteins are markers for numerous cancers, and in many cases high S100 protein levels are a prognostic indicator for poor survival. One such case is S100B, which is overproduced in a very large percentage of malignant melanoma cases. Elevated S100B protein was more recently validated to have causative effects towards cancer progression via down-regulating the tumor suppressor protein, p53. Towards eliminating this problem in melanoma, targeting S100B with small molecule inhibitors was initiated. This work relies on numerous chemical biology technologies including structural biology, computer-aided drug design, compound screening, and medicinal chemistry approaches. Another important component of drug development is the ability to test compounds and various molecular scaffolds for their efficacy in vivo. This chapter briefly describes the development of S100B inhibitors, termed SBiXs, for melanoma therapy with a focus on the inclusion of in vivo screening at an early stage in the drug discovery process.
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Affiliation(s)
- Danna B Zimmer
- Department of Biochemistry and Molecular Biology, Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, Baltimore, MD, USA.
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