1
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Deolal P, Scholz J, Ren K, Bragulat-Teixidor H, Otsuka S. Sculpting nuclear envelope identity from the endoplasmic reticulum during the cell cycle. Nucleus 2024; 15:2299632. [PMID: 38238284 PMCID: PMC10802211 DOI: 10.1080/19491034.2023.2299632] [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: 10/18/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024] Open
Abstract
The nuclear envelope (NE) regulates nuclear functions, including transcription, nucleocytoplasmic transport, and protein quality control. While the outer membrane of the NE is directly continuous with the endoplasmic reticulum (ER), the NE has an overall distinct protein composition from the ER, which is crucial for its functions. During open mitosis in higher eukaryotes, the NE disassembles during mitotic entry and then reforms as a functional territory at the end of mitosis to reestablish nucleocytoplasmic compartmentalization. In this review, we examine the known mechanisms by which the functional NE reconstitutes from the mitotic ER in the continuous ER-NE endomembrane system during open mitosis. Furthermore, based on recent findings indicating that the NE possesses unique lipid metabolism and quality control mechanisms distinct from those of the ER, we explore the maintenance of NE identity and homeostasis during interphase. We also highlight the potential significance of membrane junctions between the ER and NE.
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Affiliation(s)
- Pallavi Deolal
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
| | - Julia Scholz
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Kaike Ren
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Helena Bragulat-Teixidor
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Shotaro Otsuka
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
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2
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Gamuyao R, Chang CL. Imaging and proteomics toolkits for studying organelle contact sites. Front Cell Dev Biol 2024; 12:1466915. [PMID: 39381373 PMCID: PMC11458464 DOI: 10.3389/fcell.2024.1466915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Accepted: 09/05/2024] [Indexed: 10/10/2024] Open
Abstract
Organelle contact sites are regions where two heterologous membranes are juxtaposed by molecular tethering complexes. These contact sites are important in inter-organelle communication and cellular functional integration. However, visualizing these minute foci and identifying contact site proteomes have been challenging. In recent years, fluorescence-based methods have been developed to visualize the dynamic physical interaction of organelles while proximity labeling approaches facilitate the profiling of proteomes at contact sites. In this review, we explain the design principle for these contact site reporters: a dual-organelle interaction mechanism based on how endogenous tethers and/or tethering complexes localize to contact sites. We classify the contact site reporters into three categories: (i) single-protein systems, (ii) two-component systems with activated reporter signal upon organelle proximity, and (iii) reporters for contact site proteomes. We also highlight advanced imaging analysis with high temporal-spatial resolution and the use of machine-learning algorithms for detecting contact sites.
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Affiliation(s)
| | - Chi-Lun Chang
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States
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3
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Zunica ERM, Axelrod CL, Gilmore LA, Gnaiger E, Kirwan JP. The bioenergetic landscape of cancer. Mol Metab 2024; 86:101966. [PMID: 38876266 PMCID: PMC11259816 DOI: 10.1016/j.molmet.2024.101966] [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: 03/21/2024] [Revised: 06/08/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND Bioenergetic remodeling of core energy metabolism is essential to the initiation, survival, and progression of cancer cells through exergonic supply of adenosine triphosphate (ATP) and metabolic intermediates, as well as control of redox homeostasis. Mitochondria are evolutionarily conserved organelles that mediate cell survival by conferring energetic plasticity and adaptive potential. Mitochondrial ATP synthesis is coupled to the oxidation of a variety of substrates generated through diverse metabolic pathways. As such, inhibition of the mitochondrial bioenergetic system by restricting metabolite availability, direct inhibition of the respiratory Complexes, altering organelle structure, or coupling efficiency may restrict carcinogenic potential and cancer progression. SCOPE OF REVIEW Here, we review the role of bioenergetics as the principal conductor of energetic functions and carcinogenesis while highlighting the therapeutic potential of targeting mitochondrial functions. MAJOR CONCLUSIONS Mitochondrial bioenergetics significantly contribute to cancer initiation and survival. As a result, therapies designed to limit oxidative efficiency may reduce tumor burden and enhance the efficacy of currently available antineoplastic agents.
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Affiliation(s)
- Elizabeth R M Zunica
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Christopher L Axelrod
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - L Anne Gilmore
- Department of Clinical Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - John P Kirwan
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
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4
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Lu Y, Jiang Y, Wang F, Wu H, Hua Y. Electron Microscopic Mapping of Mitochondrial Morphology in the Cochlear Nerve Fibers. J Assoc Res Otolaryngol 2024; 25:341-354. [PMID: 38937328 PMCID: PMC11349726 DOI: 10.1007/s10162-024-00957-y] [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: 01/08/2024] [Accepted: 06/12/2024] [Indexed: 06/29/2024] Open
Abstract
To enable nervous system function, neurons are powered in a use-dependent manner by mitochondria undergoing morphological-functional adaptation. In a well-studied model system-the mammalian cochlea, auditory nerve fibers (ANFs) display distinct electrophysiological properties, which is essential for collectively sampling acoustic information of a large dynamic range. How exactly the associated mitochondrial networks are deployed in functionally differentiated ANFs remains scarcely interrogated. Here, we leverage volume electron microscopy and machine-learning-assisted image analysis to phenotype mitochondrial morphology and distribution along ANFs of full-length in the mouse cochlea inner spiral bundle. This reveals greater variance in mitochondrial size with increased ANF habenula to terminal path length. Particularly, we analyzed the ANF terminal-residing mitochondria, which are critical for local calcium uptake during sustained afferent activities. Our results suggest that terminal-specific enrichment of mitochondria, in addition to terminal size and overall mitochondrial abundance of the ANF, correlates with heterogenous mitochondrial contents of the terminal.
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Affiliation(s)
- Yan Lu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi Jiang
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fangfang Wang
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunfeng Hua
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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5
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Kolotuev I. Work smart, not hard: How array tomography can help increase the ultrastructure data output. J Microsc 2024; 295:42-60. [PMID: 37626455 DOI: 10.1111/jmi.13217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Transmission electron microscopy has been essential for understanding cell biology for over six decades. Volume electron microscopy tools, such as serial block face and focused ion beam scanning electron microscopy acquisition, brought a new era to ultrastructure analysis. 'Array Tomography' (AT) refers to sequential image acquisition of resin-embedded sample sections on a large support (coverslip, glass slide, silicon wafers) for immunolabelling with multiple fluorescent labels, occasionally combined with ultrastructure observation. Subsequently, the term was applied to generating and imaging a series of sections to acquire a 3D representation of a structure using scanning electron microscopy (SEM). Although this is a valuable application, the potential of AT is to facilitate many tasks that are difficult or even impossible to obtain by Transmission Electron Microscopy (TEM). Due to the straightforward nature and versatility of AT sample preparation and image acquisition, the technique can be applied practically to any biological sample for selected sections or volume electron microscopy analysis. Furthermore, in addition to the benefits described here, AT is compatible with morphological analysis, multiplex immunolabelling, immune-gold labelling, and correlative light and electron microscopy workflow applicable for single cells, tissue and small organisms. This versatility makes AT attractive not only for basic research but as a diagnostic tool with a simplified routine.
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Affiliation(s)
- Irina Kolotuev
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
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6
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Turegano-Lopez M, de Las Pozas F, Santuy A, Rodriguez JR, DeFelipe J, Merchan-Perez A. Tracing nerve fibers with volume electron microscopy to quantitatively analyze brain connectivity. Commun Biol 2024; 7:796. [PMID: 38951162 PMCID: PMC11217374 DOI: 10.1038/s42003-024-06491-0] [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: 12/18/2023] [Accepted: 06/21/2024] [Indexed: 07/03/2024] Open
Abstract
The highly complex structure of the brain requires an approach that can unravel its connectivity. Using volume electron microscopy and a dedicated software we can trace and measure all nerve fibers present within different samples of brain tissue. With this software tool, individual dendrites and axons are traced, obtaining a simplified "skeleton" of each fiber, which is linked to its corresponding synaptic contacts. The result is an intricate meshwork of axons and dendrites interconnected by a cloud of synaptic junctions. To test this methodology, we apply it to the stratum radiatum of the hippocampus and layers 1 and 3 of the somatosensory cortex of the mouse. We find that nerve fibers are densely packed in the neuropil, reaching up to 9 kilometers per cubic mm. We obtain the number of synapses, the number and lengths of dendrites and axons, the linear densities of synapses established by dendrites and axons, and their location on dendritic spines and shafts. The quantitative data obtained through this method enable us to identify subtle traits and differences in the synaptic organization of the samples, which might have been overlooked in a qualitative analysis.
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Affiliation(s)
- Marta Turegano-Lopez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain
| | - Felix de Las Pozas
- Visualization & Graphics Lab (VG-Lab), Universidad Rey Juan Carlos, C/Tulipán S/N, Móstoles, 28933, Madrid, Spain
| | - Andrea Santuy
- Department of Basic Sciences, Universitat Internacional de Catalunya (UIC), San Cugat del Vallès, 08195, Barcelona, Spain
| | - Jose-Rodrigo Rodriguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce, 37, 28002, Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce, 37, 28002, Madrid, Spain
| | - Angel Merchan-Perez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain.
- Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain.
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7
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Martin-Solana E, Casado-Zueras L, Torres TE, Goya GF, Fernandez-Fernandez MR, Fernandez JJ. Disruption of the mitochondrial network in a mouse model of Huntington's disease visualized by in-tissue multiscale 3D electron microscopy. Acta Neuropathol Commun 2024; 12:88. [PMID: 38840253 PMCID: PMC11151585 DOI: 10.1186/s40478-024-01802-2] [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: 04/04/2024] [Accepted: 05/27/2024] [Indexed: 06/07/2024] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the coding sequence of huntingtin protein. Initially, it predominantly affects medium-sized spiny neurons (MSSNs) of the corpus striatum. No effective treatment is still available, thus urging the identification of potential therapeutic targets. While evidence of mitochondrial structural alterations in HD exists, previous studies mainly employed 2D approaches and were performed outside the strictly native brain context. In this study, we adopted a novel multiscale approach to conduct a comprehensive 3D in situ structural analysis of mitochondrial disturbances in a mouse model of HD. We investigated MSSNs within brain tissue under optimal structural conditions utilizing state-of-the-art 3D imaging technologies, specifically FIB/SEM for the complete imaging of neuronal somas and Electron Tomography for detailed morphological examination, and image processing-based quantitative analysis. Our findings suggest a disruption of the mitochondrial network towards fragmentation in HD. The network of interlaced, slim and long mitochondria observed in healthy conditions transforms into isolated, swollen and short entities, with internal cristae disorganization, cavities and abnormally large matrix granules.
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Affiliation(s)
- Eva Martin-Solana
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | | | - Teobaldo E Torres
- Advanced Microscopy Laboratory, University of Zaragoza, Zaragoza, Spain
- Instituto de Nanociencia y Materiales de Aragon (INMA), CSIC-Universidad de Zaragoza, 50018, Zaragoza, Spain
- Department of Condensed Matter Physics, University of Zaragoza, Zaragoza, Spain
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Gerardo F Goya
- Instituto de Nanociencia y Materiales de Aragon (INMA), CSIC-Universidad de Zaragoza, 50018, Zaragoza, Spain
- Department of Condensed Matter Physics, University of Zaragoza, Zaragoza, Spain
| | | | - Jose-Jesus Fernandez
- Spanish National Research Council (CSIC, CINN), Health Research Institute of Asturias (ISPA), 33011, Oviedo, Spain.
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8
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Galaz-Montoya JG. The advent of preventive high-resolution structural histopathology by artificial-intelligence-powered cryogenic electron tomography. Front Mol Biosci 2024; 11:1390858. [PMID: 38868297 PMCID: PMC11167099 DOI: 10.3389/fmolb.2024.1390858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 05/08/2024] [Indexed: 06/14/2024] Open
Abstract
Advances in cryogenic electron microscopy (cryoEM) single particle analysis have revolutionized structural biology by facilitating the in vitro determination of atomic- and near-atomic-resolution structures for fully hydrated macromolecular complexes exhibiting compositional and conformational heterogeneity across a wide range of sizes. Cryogenic electron tomography (cryoET) and subtomogram averaging are rapidly progressing toward delivering similar insights for macromolecular complexes in situ, without requiring tags or harsh biochemical purification. Furthermore, cryoET enables the visualization of cellular and tissue phenotypes directly at molecular, nanometric resolution without chemical fixation or staining artifacts. This forward-looking review covers recent developments in cryoEM/ET and related technologies such as cryogenic focused ion beam milling scanning electron microscopy and correlative light microscopy, increasingly enhanced and supported by artificial intelligence algorithms. Their potential application to emerging concepts is discussed, primarily the prospect of complementing medical histopathology analysis. Machine learning solutions are poised to address current challenges posed by "big data" in cryoET of tissues, cells, and macromolecules, offering the promise of enabling novel, quantitative insights into disease processes, which may translate into the clinic and lead to improved diagnostics and targeted therapeutics.
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Affiliation(s)
- Jesús G. Galaz-Montoya
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA, United States
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9
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Dudka W, Salo VT, Mahamid J. Zooming into lipid droplet biology through the lens of electron microscopy. FEBS Lett 2024; 598:1127-1142. [PMID: 38726814 DOI: 10.1002/1873-3468.14899] [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: 01/26/2024] [Revised: 04/08/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Electron microscopy (EM), in its various flavors, has significantly contributed to our understanding of lipid droplets (LD) as central organelles in cellular metabolism. For example, EM has illuminated that LDs, in contrast to all other cellular organelles, are uniquely enclosed by a single phospholipid monolayer, revealed the architecture of LD contact sites with different organelles, and provided near-atomic resolution maps of key enzymes that regulate neutral lipid biosynthesis and LD biogenesis. In this review, we first provide a brief history of pivotal findings in LD biology unveiled through the lens of an electron microscope. We describe the main EM techniques used in the context of LD research and discuss their current capabilities and limitations, thereby providing a foundation for utilizing suitable EM methodology to address LD-related questions with sufficient level of structural preservation, detail, and resolution. Finally, we highlight examples where EM has recently been and is expected to be instrumental in expanding the frontiers of LD biology.
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Affiliation(s)
- Wioleta Dudka
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Cell Biology and Biophysics Unit, EMBL, Heidelberg, Germany
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10
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Zhao J, Yu X, Shentu X, Li D. The application and development of electron microscopy for three-dimensional reconstruction in life science: a review. Cell Tissue Res 2024; 396:1-18. [PMID: 38416172 DOI: 10.1007/s00441-024-03878-7] [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: 10/17/2023] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
Imaging technologies have played a pivotal role in advancing biological research by enabling visualization of biological structures and processes. While traditional electron microscopy (EM) produces two-dimensional images, emerging techniques now allow high-resolution three-dimensional (3D) characterization of specimens in situ, meeting growing needs in molecular and cellular biology. Combining transmission electron microscopy (TEM) with serial sectioning inaugurated 3D imaging, attracting biologists seeking to explore cell ultrastructure and driving advancement of 3D EM reconstruction. By comprehensively and precisely rendering internal structure and distribution, 3D TEM reconstruction provides unparalleled ultrastructural insights into cells and molecules, holding tremendous value for elucidating structure-function relationships and broadly propelling structural biology. Here, we first introduce the principle of 3D reconstruction of cells and tissues by classical approaches in TEM and then discuss modern technologies utilizing TEM and on new SEM-based as well as cryo-electron microscope (cryo-EM) techniques. 3D reconstruction techniques from serial sections, electron tomography (ET), and the recent single-particle analysis (SPA) are examined; the focused ion beam scanning electron microscopy (FIB-SEM), the serial block-face scanning electron microscopy (SBF-SEM), and automatic tape-collecting lathe ultramicrotome (ATUM-SEM) for 3D reconstruction of large volumes are discussed. Finally, we review the challenges and development prospects of these technologies in life science. It aims to provide an informative reference for biological researchers.
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Affiliation(s)
- Jingjing Zhao
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xuping Shentu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Danting Li
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China.
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11
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Boergens KM, Wildenberg G, Li R, Lambert L, Moradi A, Stam G, Tromp R, van der Molen SJ, King SB, Kasthuri N. Photoemission electron microscopy for connectomics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.05.556423. [PMID: 37771915 PMCID: PMC10525389 DOI: 10.1101/2023.09.05.556423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Detailing the physical basis of neural circuits with large-volume serial electron microscopy (EM), 'connectomics', has emerged as an invaluable tool in the neuroscience armamentarium. However, imaging synaptic resolution connectomes is currently limited to either transmission electron microscopy (TEM) or scanning electron microscopy (SEM). Here, we describe a third way, using photoemission electron microscopy (PEEM) which illuminates ultra-thin brain slices collected on solid substrates with UV light and images the photoelectron emission pattern with a wide-field electron microscope. PEEM works with existing sample preparations for EM and routinely provides sufficient resolution and contrast to reveal myelinated axons, somata, dendrites, and sub-cellular organelles. Under optimized conditions, PEEM provides synaptic resolution; and simulation and experiments show that PEEM can be transformatively fast, at Gigahertz pixel rates. We conclude that PEEM imaging leverages attractive aspects of SEM and TEM, namely reliable sample collection on robust substrates combined with fast wide-field imaging, and could enable faster data acquisition for next-generation circuit mapping.
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12
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Franzkoch R, Anand A, Breitsprecher L, Psathaki OE, Barisch C. Resolving exit strategies of mycobacteria in Dictyostelium discoideum by combining high-pressure freezing with 3D-correlative light and electron microscopy. Mol Microbiol 2024; 121:593-604. [PMID: 38063129 DOI: 10.1111/mmi.15205] [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: 05/15/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 03/12/2024]
Abstract
The infection course of Mycobacterium tuberculosis is highly dynamic and comprises sequential stages that require damaging and crossing of several membranes to enable the translocation of the bacteria into the cytosol or their escape from the host. Many important breakthroughs such as the restriction of mycobacteria by the autophagy pathway and the recruitment of sophisticated host repair machineries to the Mycobacterium-containing vacuole have been gained in the Dictyostelium discoideum/M. marinum system. Despite the availability of well-established light and advanced electron microscopy techniques in this system, a correlative approach integrating both methods with near-native ultrastructural preservation is currently lacking. This is most likely due to the low ability of D. discoideum to adhere to surfaces, which results in cell loss even after fixation. To address this problem, we improved the adhesion of cells and developed a straightforward and convenient workflow for 3D-correlative light and electron microscopy. This approach includes high-pressure freezing, which is an excellent technique for preserving membranes. Thus, our method allows to monitor the ultrastructural aspects of vacuole escape which is of central importance for the survival and dissemination of bacterial pathogens.
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Affiliation(s)
- Rico Franzkoch
- iBiOs-integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück, Germany
- Division of Microbiology, Department of Biology, University of Osnabrück, Osnabrück, Germany
| | - Aby Anand
- Center of Cellular Nanoanalytics, Osnabrück, Germany
- Division of Molecular Infection Biology, Department of Biology, University of Osnabrück, Osnabrück, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Division of Host-Microbe Interactome, Research Center Borstel - Leibniz Lung Center (FZB), Borstel, Germany
- Department of Biology, University of Hamburg, Hamburg, Germany
| | - Leonhard Breitsprecher
- iBiOs-integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück, Germany
- Division of Microbiology, Department of Biology, University of Osnabrück, Osnabrück, Germany
| | - Olympia E Psathaki
- iBiOs-integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück, Germany
| | - Caroline Barisch
- Center of Cellular Nanoanalytics, Osnabrück, Germany
- Division of Molecular Infection Biology, Department of Biology, University of Osnabrück, Osnabrück, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Division of Host-Microbe Interactome, Research Center Borstel - Leibniz Lung Center (FZB), Borstel, Germany
- Department of Biology, University of Hamburg, Hamburg, Germany
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13
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Kang SWS, Cunningham RP, Miller CB, Brown LA, Cultraro CM, Harned A, Narayan K, Hernandez J, Jenkins LM, Lobanov A, Cam M, Porat-Shliom N. A spatial map of hepatic mitochondria uncovers functional heterogeneity shaped by nutrient-sensing signaling. Nat Commun 2024; 15:1799. [PMID: 38418824 PMCID: PMC10902380 DOI: 10.1038/s41467-024-45751-9] [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: 04/24/2023] [Accepted: 02/04/2024] [Indexed: 03/02/2024] Open
Abstract
In the liver, mitochondria are exposed to different concentrations of nutrients due to their spatial positioning across the periportal and pericentral axis. How the mitochondria sense and integrate these signals to respond and maintain homeostasis is not known. Here, we combine intravital microscopy, spatial proteomics, and functional assessment to investigate mitochondrial heterogeneity in the context of liver zonation. We find that periportal and pericentral mitochondria are morphologically and functionally distinct; beta-oxidation is elevated in periportal regions, while lipid synthesis is predominant in the pericentral mitochondria. In addition, comparative phosphoproteomics reveals spatially distinct patterns of mitochondrial composition and potential regulation via phosphorylation. Acute pharmacological modulation of nutrient sensing through AMPK and mTOR shifts mitochondrial phenotypes in the periportal and pericentral regions, linking nutrient gradients across the lobule and mitochondrial heterogeneity. This study highlights the role of protein phosphorylation in mitochondrial structure, function, and overall homeostasis in hepatic metabolic zonation. These findings have important implications for liver physiology and disease.
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Affiliation(s)
- Sun Woo Sophie Kang
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Rory P Cunningham
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Colin B Miller
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Lauryn A Brown
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Constance M Cultraro
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Adam Harned
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Cancer Research Technology Programs, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Cancer Research Technology Programs, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Jonathan Hernandez
- Surgical Oncology Program, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Lisa M Jenkins
- Laboratory of Cell Biology, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Alexei Lobanov
- CCR Collaborative Bioinformatics Resource (CCBR) National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Maggie Cam
- CCR Collaborative Bioinformatics Resource (CCBR) National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Natalie Porat-Shliom
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA.
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14
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Porat-Shliom N. Compartmentalization, cooperation, and communication: The 3Cs of Hepatocyte zonation. Curr Opin Cell Biol 2024; 86:102292. [PMID: 38064779 PMCID: PMC10922296 DOI: 10.1016/j.ceb.2023.102292] [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: 08/18/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 02/15/2024]
Abstract
The unique architecture of the liver allows for spatial compartmentalization of its functions, also known as liver zonation. In contrast to organelles and cells, this compartment is devoid of a surrounding membrane, rendering traditional biochemical tools ineffective for studying liver zonation. Recent advancements in tissue imaging and single-cell technologies have provided new insights into the complexity of tissue organization, rich cellular composition, and the gradients that shape zonation. Hepatocyte gene expression profiles and metabolic programs differ based on their location. Non-parenchymal cells further support hepatocytes from different zones through local secretion of factors that instruct hepatocyte activities. Collectively, these elements form a cohesive and dynamic network of cell-cell interactions that vary across space, time, and disease states. This review will examine the cell biology of hepatocytes in vivo, presenting the latest discoveries and emerging principles that govern tissue-level and sub-cellular compartmentalization.
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Affiliation(s)
- Natalie Porat-Shliom
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA.
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15
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Vijayakumaran A, Abuammar A, Medagedara O, Narayan K, Mennella V. Airway Cells 3D Reconstruction via Manual and Machine-Learning Aided Segmentation of Volume EM Datasets. Methods Mol Biol 2024; 2725:131-146. [PMID: 37856022 DOI: 10.1007/978-1-0716-3507-0_8] [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] [Indexed: 10/20/2023]
Abstract
Volume electron microscopy (vEM) is a high-resolution imaging technique capable of revealing the 3D structure of cells, tissues, and model organisms. This imaging modality is gaining prominence due to its ability to provide a comprehensive view of cells at the nanometer scale. The visualization and quantitative analysis of individual subcellular structures however requires segmentation of each 2D electron micrograph slice of the 3D vEM dataset; this process is extremely laborious de facto limiting its applications and throughput. To address these limitations, deep learning approaches have been recently developed including Empanada-Napari plugin, an open-source tool for automated segmentation based on a Panoptic-DeepLab (PDL) architecture. In this chapter, we provide a step-by-step protocol describing the process of manual segmentation using 3dMOD within the IMOD package and the process of automated segmentation using Empanada-Napari plugins for the 3D reconstruction of airway cellular structures.
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Affiliation(s)
- Aaran Vijayakumaran
- Medical Research Council Toxicology Unit, School of Biological Sciences, University of Cambridge, Cambridge, UK
| | - Analle Abuammar
- Medical Research Council Toxicology Unit, School of Biological Sciences, University of Cambridge, Cambridge, UK
| | - Odara Medagedara
- Medical Research Council Toxicology Unit, School of Biological Sciences, University of Cambridge, Cambridge, UK
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Vito Mennella
- Medical Research Council Toxicology Unit, School of Biological Sciences, University of Cambridge, Cambridge, UK.
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16
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Winn MD. Communities in structural biology. Nat Struct Mol Biol 2024; 31:6-7. [PMID: 38253661 DOI: 10.1038/s41594-023-01197-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Affiliation(s)
- Martyn David Winn
- Science & Technology Facilities Council, Research Complex at Harwell, Didcot, UK.
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17
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Kang SWS, Cunningham RP, Miller CB, Brown LA, Cultraro CM, Harned A, Narayan K, Hernandez J, Jenkins LM, Lobanov A, Cam M, Porat-Shliom N. A spatial map of hepatic mitochondria uncovers functional heterogeneity shaped by nutrient-sensing signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.13.536717. [PMID: 37333328 PMCID: PMC10274915 DOI: 10.1101/2023.04.13.536717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
In the liver, mitochondria are exposed to different concentrations of nutrients due to their spatial positioning across the periportal (PP) and pericentral (PC) axis. How these mitochondria sense and integrate these signals to respond and maintain homeostasis is not known. Here, we combined intravital microscopy, spatial proteomics, and functional assessment to investigate mitochondrial heterogeneity in the context of liver zonation. We found that PP and PC mitochondria are morphologically and functionally distinct; beta-oxidation was elevated in PP regions, while lipid synthesis was predominant in the PC mitochondria. In addition, comparative phosphoproteomics revealed spatially distinct patterns of mitochondrial composition and potential regulation via phosphorylation. Acute pharmacological modulation of nutrient sensing through AMPK and mTOR shifted mitochondrial phenotypes in the PP and PC regions, linking nutrient gradients across the lobule and mitochondrial heterogeneity. This study highlights the role of protein phosphorylation in mitochondrial structure, function, and overall homeostasis in hepatic metabolic zonation. These findings have important implications for liver physiology and disease.
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Affiliation(s)
- Sun Woo Sophie Kang
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Rory P. Cunningham
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Colin B. Miller
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Lauryn A. Brown
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Constance M. Cultraro
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Adam Harned
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jonathan Hernandez
- Surgical Oncology Program, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Lisa M. Jenkins
- Laboratory of Cell Biology, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Alexei Lobanov
- CCR Collaborative Bioinformatics Resource (CCBR) National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Maggie Cam
- CCR Collaborative Bioinformatics Resource (CCBR) National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Natalie Porat-Shliom
- Cell Biology and Imaging Section, Thoracic and GI Malignancies Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, Maryland, USA
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18
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Lewis RM. Volume electron microscopy reveals placental ultrastructure in 3D. Placenta 2023; 141:78-83. [PMID: 37487796 DOI: 10.1016/j.placenta.2023.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/26/2023]
Abstract
Many structures necessary for placental function can only be visualised at the ultrastructural scale. Recent technological advances have made Volume electron microscopy (volume EM) approaches much more accessible. Volume EM allows the ultrastructure of tissues, cells and organelles to be visualised in 3D. It also allows the 3D spatial relationships between these structures to be determined. This review will highlight the potential for volume EM to advance our understanding of placental ultrastructure. It will focus on the human term placenta highlighting key findings spanning the placental barrier from trans-syncytial nanopores in the syncytiotrophoblast to tunnelling nanotubes in the fetal capillary endothelium. Volume EM is advancing our understanding of placental ultrastructure, but to fully exploit its potential, it will be necessary to use it as part of multimodal and correlative workflows. The complementary strengths of these different approaches can complement volume EM and reveal the biological significance of its novel observations. The use of volume EM also highlighted how ultrastructural features might underpin pregnancy pathologies and demonstrates the need for more research in this underrepresented area.
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19
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Andrade López JM, Pani AM, Wu M, Gerhart J, Lowe CJ. Molecular characterization of nervous system organization in the hemichordate acorn worm Saccoglossus kowalevskii. PLoS Biol 2023; 21:e3002242. [PMID: 37725784 PMCID: PMC10508912 DOI: 10.1371/journal.pbio.3002242] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/11/2023] [Indexed: 09/21/2023] Open
Abstract
Hemichordates are an important group for investigating the evolution of bilaterian nervous systems. As the closest chordate outgroup with a bilaterally symmetric adult body plan, hemichordates are particularly informative for exploring the origins of chordates. Despite the importance of hemichordate neuroanatomy for testing hypotheses on deuterostome and chordate evolution, adult hemichordate nervous systems have not been comprehensively described using molecular techniques, and classic histological descriptions disagree on basic aspects of nervous system organization. A molecular description of hemichordate nervous system organization is important for both anatomical comparisons across phyla and for attempts to understand how conserved gene regulatory programs for ectodermal patterning relate to morphological evolution in deep time. Here, we describe the basic organization of the adult hemichordate Saccoglossus kowalevskii nervous system using immunofluorescence, in situ hybridization, and transgenic reporters to visualize neurons, neuropil, and key neuronal cell types. Consistent with previous descriptions, we found the S. kowalevskii nervous system consists of a pervasive nerve plexus concentrated in the anterior, along with nerve cords on both the dorsal and ventral side. Neuronal cell types exhibited clear anteroposterior and dorsoventral regionalization in multiple areas of the body. We observed spatially demarcated expression patterns for many genes involved in synthesis or transport of neurotransmitters and neuropeptides but did not observe clear distinctions between putatively centralized and decentralized portions of the nervous system. The plexus shows regionalized structure and is consistent with the proboscis base as a major site for information processing rather than the dorsal nerve cord. In the trunk, there is a clear division of cell types between the dorsal and ventral cords, suggesting differences in function. The absence of neural processes crossing the basement membrane into muscle and extensive axonal varicosities suggest that volume transmission may play an important role in neural function. These data now facilitate more informed neural comparisons between hemichordates and other groups, contributing to broader debates on the origins and evolution of bilaterian nervous systems.
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Affiliation(s)
- José M. Andrade López
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Ariel M. Pani
- Departments of Biology and Cell Biology, University of Virginia, Charlottesville, Virginia, Unites States of America
| | - Mike Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, California, Unites States of America
| | - John Gerhart
- Department of Molecular and Cell Biology, University of California, Berkeley, California, Unites States of America
| | - Christopher J. Lowe
- Department of Biology, Stanford University, Stanford, California, United States of America
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