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Hackett MJ. A commentary on studies of brain iron accumulation during ageing. J Biol Inorg Chem 2024; 29:385-394. [PMID: 38735007 PMCID: PMC11186910 DOI: 10.1007/s00775-024-02060-2] [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: 12/04/2023] [Accepted: 04/29/2024] [Indexed: 05/13/2024]
Abstract
Brain iron content is widely reported to increase during "ageing", across multiple species from nematodes, rodents (mice and rats) and humans. Given the redox-active properties of iron, there has been a large research focus on iron-mediated oxidative stress as a contributor to tissue damage during natural ageing, and also as a risk factor for neurodegenerative disease. Surprisingly, however, the majority of published studies have not investigated brain iron homeostasis during the biological time period of senescence, and thus knowledge of how brain homeostasis changes during this critical stage of life largely remains unknown. This commentary examines the literature published on the topic of brain iron homeostasis during ageing, providing a critique on limitations of currently used experimental designs. The commentary also aims to highlight that although much research attention has been given to iron accumulation or iron overload as a pathological feature of ageing, there is evidence to support functional iron deficiency may exist, and this should not be overlooked in studies of ageing or neurodegenerative disease.
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Affiliation(s)
- Mark J Hackett
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia.
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6102, Australia.
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Shimamura T, Takeo Y, Moriya F, Kimura T, Shimura M, Senba Y, Kishimoto H, Ohashi H, Shimba K, Jimbo Y, Mimura H. Ultracompact mirror device for forming 20-nm achromatic soft-X-ray focus toward multimodal and multicolor nanoanalyses. Nat Commun 2024; 15:665. [PMID: 38326328 PMCID: PMC10850520 DOI: 10.1038/s41467-023-44269-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 12/06/2023] [Indexed: 02/09/2024] Open
Abstract
Nanoscale soft-X-ray microscopy is a powerful analysis tool in biological, chemical, and physical sciences. To enhance its probe sensitivity and leverage multimodal soft-X-ray microscopy, precise achromatic focusing devices, which are challenging to fabricate, are essential. Here, we develop an ultracompact Kirkpatrick-Baez (ucKB) mirror, which is ideal for the high-performance nanofocusing of broadband-energy X-rays. We apply our advanced fabrication techniques and short-focal-length strategy to realize diffraction-limited focusing over the entire soft-X-ray range. We achieve a focus size of 20.4 nm at 2 keV, which represents a significant improvement in achromatic soft-X-ray focusing. The ucKB mirror extends soft-X-ray fluorescence microscopy by producing a bicolor nanoprobe with a 1- or 2-keV photon energy. We propose a subcellular chemical mapping method that allows a comprehensive analysis of specimen morphology and the distribution of light elements and metal elements. ucKB mirrors will improve soft-X-ray nanoanalyses by facilitating photon-hungry, multimodal, and polychromatic methods, even with table-top X-ray sources.
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Affiliation(s)
- Takenori Shimamura
- School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan.
- Japan Synchrotron Radiation Research Institute, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5198, Japan.
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan.
| | - Yoko Takeo
- Japan Synchrotron Radiation Research Institute, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5198, Japan
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - Fumika Moriya
- School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan
| | - Takashi Kimura
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - Mari Shimura
- RIKEN SPring-8 Center, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5148, Japan
- Department of Refractory Viral Infection, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655, Japan
| | - Yasunori Senba
- Japan Synchrotron Radiation Research Institute, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5148, Japan
| | - Hikaru Kishimoto
- Japan Synchrotron Radiation Research Institute, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5198, Japan
| | - Haruhiko Ohashi
- Japan Synchrotron Radiation Research Institute, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5148, Japan
| | - Kenta Shimba
- School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan
| | - Yasuhiko Jimbo
- School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan
| | - Hidekazu Mimura
- RIKEN SPring-8 Center, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5148, Japan.
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, 153-8904, Japan.
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Correlative nano-imaging of metals and proteins in primary neurons by synchrotron X-ray fluorescence and STED super resolution microscopy: Experimental validation. J Neurosci Methods 2022; 381:109702. [PMID: 36064068 DOI: 10.1016/j.jneumeth.2022.109702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND It is becoming increasingly clear that biological metals such as iron, copper or zinc are involved in synaptic functions, and in particular in the mechanisms of synaptogenesis and subsequent plasticity. Understanding the role of metals on synaptic functions is a difficult challenge due to the very low concentration of these elements in neurons and to the submicrometer size of synaptic compartments. NEW METHOD To address this challenge we have developed a correlative nano-imaging approach combining metal and protein detection. First, stimulated emission depletion (STED) microscopy, a super resolution optical microscopy technique, is applied to locate fluorescently labeled proteins. Then, synchrotron radiation induced X-ray fluorescence (SXRF) is performed on the same regions of interest, e.g. synaptic compartments. RESULTS We present here the principle scheme that allows this correlative nano-imaging and its experimental validation. We applied this correlative nano-imaging to the study of the physiological distribution of metals in synaptic compartments of primary rat hippocampal neurons. We thus compared the nanometric distribution of metals with that of synaptic proteins, such as PSD95 or cytoskeleton proteins. COMPARISON WITH EXISTING METHOD(S) Compared to correlative imaging approaches currently used to characterize synaptic structures, such as electron microscopy correlated with optical fluorescence, our approach allows for ultra-sensitive detection of trace metals using highly focused synchrotron radiation beams. CONCLUSION We provide proof-of-principle for correlative imaging of metals and proteins at the synaptic scale and discuss the present limitations and future developments in this area.
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Zee DZ, MacRenaris KW, O'Halloran TV. Quantitative imaging approaches to understanding biological processing of metal ions. Curr Opin Chem Biol 2022; 69:102152. [PMID: 35561425 PMCID: PMC9329216 DOI: 10.1016/j.cbpa.2022.102152] [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: 02/14/2022] [Revised: 03/19/2022] [Accepted: 03/28/2022] [Indexed: 11/18/2022]
Abstract
Faster, more sensitive, and higher resolution quantitative instrumentation are aiding a deeper understanding of how inorganic chemistry regulates key biological processes. Researchers can now image and quantify metals with subcellular resolution, leading to a vast array of new discoveries in organismal development, pathology, and disease. Metals have recently been implicated in several diseases such as Parkinson's, Alzheimers, ischemic stroke, and colorectal cancer that would not be possible without these advancements. In this review, instead of focusing on instrumentation we focus on recent applications of label-free elemental imaging and quantification and how these tools can lead to a broader understanding of metals role in systems biology and human pathology.
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Affiliation(s)
- David Z Zee
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Keith W MacRenaris
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Thomas V O'Halloran
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA; Department of Chemistry, Michigan State University, East Lansing, MI, USA; Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA; Department of Chemistry, Northwestern University, Evanston, IL, USA; Elemental Health Institute, Michigan State University, East Lansing, MI, USA.
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