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Wang Y, Song Y, Zhang L, Huang X. The paradoxical role of zinc on microglia. J Trace Elem Med Biol 2024; 83:127380. [PMID: 38171037 DOI: 10.1016/j.jtemb.2023.127380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/25/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024]
Abstract
Zinc is an essential trace element for humans, and its homeostasis is essential for the health of the central nervous system. Microglia, the resident immune cells in the central nervous system, play the roles of sustaining, nourishing, and immune surveillance. Microglia are sensitive to microenvironment changes and are easily activated to M1 phenotype to enhance disease progression or the M2 phenotype to improve peripheral nerves injury repair. Zinc is requisite for microglial activation, However, the cytotoxicity outcome of zinc against microglia, the activated microglia phenotype, and activated microglia function are ambiguous. Herein, we have reviewed the neurological function of zinc and microglia, particularly the ambiguous role of zinc on microglia. We also pay attention to the role of zinc homeostasis on microglial function within the central nervous system disease. Finally, we observe the relationship between zinc and microglia, attempting to design new therapeutic measures against major nervous system disorders.
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Affiliation(s)
- Yehong Wang
- Graduate Faculty, Xi'an Physical Education University, Xi'an 710068, PR China; Hunan Provincial Key Laboratory of Dong Medicine, Ethnic Medicine Research Center, Hunan University of Medicine, Huaihua 418000, PR China
| | - Yi Song
- Department of Neurosurgery, Chongqing University Three Gorges Hospital, Chongqing 404100, PR China.
| | - Lingdang Zhang
- Department of Neurosurgery, Chongqing University Three Gorges Hospital, Chongqing 404100, PR China
| | - Xiao Huang
- Hunan Provincial Key Laboratory of Dong Medicine, Ethnic Medicine Research Center, Hunan University of Medicine, Huaihua 418000, PR China.
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Paris T, Kiss A, Signor L, Lutfalla G, Blaise M, Boeri Erba E, Chaloin L, Yatime L. The IbeA protein from adherent invasive Escherichia coli is a flavoprotein sharing structural homology with FAD-dependent oxidoreductases. FEBS J 2024; 291:177-203. [PMID: 37786987 DOI: 10.1111/febs.16969] [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: 06/30/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
Invasion of brain endothelium protein A (IbeA) is a virulence factor specific to pathogenic Escherichia coli. Originally identified in the K1 strain causing neonatal meningitis, it was more recently found in avian pathogenic Escherichia coli (APEC) and adherent invasive Escherichia coli (AIEC). In these bacteria, IbeA facilitates host cell invasion and intracellular survival, in particular, under harsh conditions like oxidative stress. Furthermore, IbeA from AIEC contributes to intramacrophage survival and replication, thus enhancing the inflammatory response within the intestine. Therefore, this factor is a promising drug target for anti-AIEC strategies in the context of Crohn's disease. Despite such an important role, the biological function of IbeA remains largely unknown. In particular, its exact nature and cellular localization, i.e., membrane-bound invasin versus cytosolic factor, are still of debate. Here, we developed an efficient protocol for recombinant expression of IbeA under native conditions and demonstrated that IbeA from AIEC is a soluble, homodimeric flavoprotein. Using mass spectrometry and tryptophan fluorescence measurements, we further showed that IbeA preferentially binds flavin adenine dinucleotide (FAD), with an affinity in the one-hundred nanomolar range and optimal binding under reducing conditions. 3D-modeling with AlphaFold revealed that IbeA shares strong structural homology with FAD-dependent oxidoreductases. Finally, we used ligand docking, mutational analyses, and molecular dynamics simulations to identify the FAD binding pocket within IbeA and characterize possible conformational changes occurring upon ligand binding. Overall, we suggest that the role of IbeA in the survival of AIEC within host cells, notably macrophages, is linked to modulation of redox processes.
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Affiliation(s)
- Théo Paris
- LPHI, Univ. Montpellier, CNRS, INSERM, France
| | - Agneta Kiss
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Luca Signor
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
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Silvers R, Stephan JR, Griffin RG, Nolan EM. Molecular Basis of Ca(II)-Induced Tetramerization and Transition-Metal Sequestration in Human Calprotectin. J Am Chem Soc 2021; 143:18073-18090. [PMID: 34699194 PMCID: PMC8643164 DOI: 10.1021/jacs.1c06402] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human calprotectin (CP, S100A8/S100A9 oligomer, MRP8/MRP14 oligomer) is an abundant innate immune protein that contributes to the host metal-withholding response. Its ability to sequester transition metal nutrients from microbial pathogens depends on a complex interplay of Ca(II) binding and self-association, which converts the αβ heterodimeric apo protein into a Ca(II)-bound (αβ)2 heterotetramer that displays enhanced transition metal affinities, antimicrobial activity, and protease stability. A paucity of structural data on the αβ heterodimer has hampered molecular understanding of how Ca(II) binding enables CP to exert its metal-sequestering innate immune function. We report solution NMR data that reveal how Ca(II) binding affects the structure and dynamics of the CP αβ heterodimer. These studies provide a structural model in which the apo αβ heterodimer undergoes conformational exchange and switches between two states, a tetramerization-incompetent or "inactive" state and a tetramerization-competent or "active" state. Ca(II) binding to the EF-hands of the αβ heterodimer causes the active state to predominate, resulting in self-association and formation of the (αβ)2 heterotetramer. Moreover, Ca(II) binding causes local and allosteric ordering of the His3Asp and His6 metal-binding sites. Ca(II) binding to the noncanonical EF-hand of S100A9 positions (A9)D30 and organizes the His3Asp site. Remarkably, Ca(II) binding causes allosteric effects in the C-terminal region of helix αIV of S100A9, which stabilize the α-helicity at positions H91 and H95 and thereby organize the functionally versatile His6 site. Collectively, this study illuminates the molecular basis for how CP responds to high extracellular Ca(II) concentrations, which enables its metal-sequestering host-defense function.
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Affiliation(s)
- Robert Silvers
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL 32306, USA
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - Jules R. Stephan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert G. Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Elizabeth M. Nolan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Daitoku H, Someya M, Kako K, Hayashi T, Tajima T, Haruki H, Sekiguchi N, Uetake T, Akimoto Y, Fukamizu A. siRNA screening identifies METTL9 as a histidine Nπ-methyltransferase that targets the proinflammatory protein S100A9. J Biol Chem 2021; 297:101230. [PMID: 34562450 PMCID: PMC8571522 DOI: 10.1016/j.jbc.2021.101230] [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: 07/14/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 11/18/2022] Open
Abstract
Protein methylation is one of the most common post-translational modifications observed in basic amino acid residues, including lysine, arginine, and histidine. Histidine methylation occurs on the distal or proximal nitrogen atom of its imidazole ring, producing two isomers: Nτ-methylhistidine or Nπ-methylhistidine. However, the biological significance of protein histidine methylation remains largely unclear owing in part to the very limited knowledge about its contributing enzymes. Here, we identified mammalian seven-β-strand methyltransferase METTL9 as a histidine Nπ-methyltransferase by siRNA screening coupled with methylhistidine analysis using LC–tandem MS. We demonstrated that METTL9 catalyzes Nπ-methylhistidine formation in the proinflammatory protein S100A9, but not that of myosin light chain kinase MYLK2, in vivo and in vitro. METTL9 does not affect the heterodimer formation of S100A9 and S100A8, although Nπ-methylation of S100A9 at His-107 overlaps with a zinc-binding site, attenuating its affinity for zinc. Given that S100A9 exerts an antimicrobial activity, probably by chelation of zinc essential for the growth of bacteria and fungi, METTL9-mediated S100A9 methylation might be involved in the innate immune response to bacterial and fungal infection. Thus, our findings suggest a functional consequence for protein histidine Nπ-methylation and may add a new layer of complexity to the regulatory mechanisms of post-translational methylation.
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Affiliation(s)
- Hiroaki Daitoku
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan.
| | - Momoka Someya
- Master's Program in Agro-Bioresources Science and Technology, Degree Programs in Life and Earth Sciences, Graduate School of Sciences and Technology, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Koichiro Kako
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takahiro Hayashi
- Doctoral Program in Life and Agricultural Sciences, Degree Programs in Life and Earth Sciences, Graduate School of Sciences and Technology, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tatsuya Tajima
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hikari Haruki
- Master's Program in Agro-Bioresources Science and Technology, Degree Programs in Life and Earth Sciences, Graduate School of Sciences and Technology, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Naoki Sekiguchi
- College of Agro-Biological Resource Sciences, School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Toru Uetake
- Master's Program in Agro-Bioresources Science and Technology, Degree Programs in Life and Earth Sciences, Graduate School of Sciences and Technology, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuto Akimoto
- College of Agro-Biological Resource Sciences, School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Akiyoshi Fukamizu
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan; The World Premier International Research Center Initiative (WPI), International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan; AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo, Japan.
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