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Hu S, Xie Z, Wang B, Chen Y, Jing Z, Hao Y, Yao J, Wu X, Huo J, Wei A, Qin Y, Dong N, Zheng C, Song Q, Long J, Kang X, Wang C, Xu H. STED Imaging of Vesicular Endocytosis in the Synapse. Neurosci Bull 2024:10.1007/s12264-024-01254-7. [PMID: 38976218 DOI: 10.1007/s12264-024-01254-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 04/08/2024] [Indexed: 07/09/2024] Open
Abstract
Endocytosis is a fundamental biological process that couples exocytosis to maintain the homeostasis of the plasma membrane and sustained neurotransmission. Super-resolution microscopy enables optical imaging of exocytosis and endocytosis in live cells and makes an essential contribution to understanding molecular mechanisms of endocytosis in neuronal somata and other types of cells. However, visualization of exo-endocytic events at the single vesicular level in a synapse with optical imaging remains a great challenge to reveal mechanisms governing the synaptic exo-endocytotic coupling. In this protocol, we describe the technical details of stimulated emission depletion (STED) imaging of synaptic endocytosis at the single-vesicle level, from sample preparation and microscopy calibration to data acquisition and analysis.
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Affiliation(s)
- Shaoqin Hu
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Zhenli Xie
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Bianbian Wang
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yang Chen
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Zexin Jing
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Ying Hao
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jingyu Yao
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xuanang Wu
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jingxiao Huo
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Anqi Wei
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yuhao Qin
- Key Laboratory of Medical Electrophysiology, Ministry of Education of China, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, and the Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China
| | - Nan Dong
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Chaowen Zheng
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Qian Song
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jiangang Long
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xinjiang Kang
- College of Life Sciences, Liaocheng University, Liaocheng, 252059, China.
- Key Laboratory of Medical Electrophysiology, Ministry of Education of China, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, and the Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China.
| | - Changhe Wang
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China.
- Key Laboratory of Medical Electrophysiology, Ministry of Education of China, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, and the Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China.
| | - Huadong Xu
- Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Neurology, the First Affiliated Hospital, Core Facilities Sharing Platform, Xi'an Jiaotong University, Xi'an, 710049, China.
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Nawara TJ, Yuan J, Seeley LD, Sztul E, Mattheyses AL. Fluidic shear stress alters clathrin dynamics and vesicle formation in endothelial cells. Biophys J 2024:S0006-3495(24)00390-4. [PMID: 38853434 DOI: 10.1016/j.bpj.2024.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/26/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024] Open
Abstract
Endothelial cells (ECs) experience a variety of highly dynamic mechanical stresses. Among others, cyclic stretch and increased plasma membrane tension inhibit clathrin-mediated endocytosis (CME) in non-ECs. It remains elusive how ECs maintain CME in these biophysically unfavorable conditions. Previously, we have used simultaneous two-wavelength axial ratiometry (STAR) microscopy to show that endocytic dynamics are similar between statically cultured human umbilical vein endothelial cells (HUVECs) and fibroblast-like Cos-7 cells. Here, we asked whether biophysical stresses generated by blood flow influence CME. We used our data processing platform-DrSTAR-to examine if clathrin dynamics are altered in HUVECs after experiencing fluidic shear stress (FSS). We found that HUVECs cultivated under a physiological level of FSS had increased clathrin dynamics compared with static controls. FSS increased both clathrin-coated vesicle formation and nonproductive flat clathrin lattices by 2.3-fold and 1.9-fold, respectively. The curvature-positive events had significantly delayed curvature initiation relative to clathrin recruitment in flow-stimulated cells, highlighting a shift toward flat-to-curved clathrin transitions in vesicle formation. Overall, our findings indicate that clathrin dynamics and clathrin-coated vesicle formation can be modulated by the local physiological environment and represent an important regulatory mechanism.
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Affiliation(s)
- Tomasz J Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jie Yuan
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Leslie D Seeley
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Elizabeth Sztul
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama.
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Wu LG, Chan CY. Membrane transformations of fusion and budding. Nat Commun 2024; 15:21. [PMID: 38167896 PMCID: PMC10761761 DOI: 10.1038/s41467-023-44539-7] [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: 06/07/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024] Open
Abstract
Membrane fusion and budding mediate fundamental processes like intracellular trafficking, exocytosis, and endocytosis. Fusion is thought to open a nanometer-range pore that may subsequently close or dilate irreversibly, whereas budding transforms flat membranes into vesicles. Reviewing recent breakthroughs in real-time visualization of membrane transformations well exceeding this classical view, we synthesize a new model and describe its underlying mechanistic principles and functions. Fusion involves hemi-to-full fusion, pore expansion, constriction and/or closure while fusing vesicles may shrink, enlarge, or receive another vesicle fusion; endocytosis follows exocytosis primarily by closing Ω-shaped profiles pre-formed through the flat-to-Λ-to-Ω-shape transition or formed via fusion. Calcium/SNARE-dependent fusion machinery, cytoskeleton-dependent membrane tension, osmotic pressure, calcium/dynamin-dependent fission machinery, and actin/dynamin-dependent force machinery work together to generate fusion and budding modes differing in pore status, vesicle size, speed and quantity, controls release probability, synchronization and content release rates/amounts, and underlies exo-endocytosis coupling to maintain membrane homeostasis. These transformations, underlying mechanisms, and functions may be conserved for fusion and budding in general.
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Affiliation(s)
- Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Chung Yu Chan
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
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Nawara TJ, Sztul E, Mattheyses AL. Fluidic shear stress alters clathrin dynamics and vesicle formation in endothelial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.02.572628. [PMID: 38260513 PMCID: PMC10802377 DOI: 10.1101/2024.01.02.572628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Endothelial cells (ECs) experience a variety of highly dynamic mechanical stresses. Among others, cyclic stretch and increased plasma membrane tension inhibit clathrin-mediated endocytosis (CME) in non-ECs cells. How ECs overcome such unfavorable, from biophysical perspective, conditions and maintain CME remains elusive. Previously, we have used simultaneous two-wavelength axial ratiometry (STAR) microscopy to show that endocytic dynamics are similar between statically cultured human umbilical vein endothelial cells (HUVECs) and fibroblast-like Cos-7 cells. Here we asked whether biophysical stresses generated by blood flow could favor one mechanism of clathrin-coated vesicle formation to overcome environment present in vasculature. We used our data processing platform - DrSTAR - to examine if clathrin dynamics are altered in HUVECs grown under fluidic sheer stress (FSS). Surprisingly, we found that FSS led to an increase in clathrin dynamics. In HUVECs grown under FSS we observed a 2.3-fold increase in clathrin-coated vesicle formation and a 1.9-fold increase in non-productive flat clathrin lattices compared to cells grown in static conditions. The curvature-positive events had significantly delayed curvature initiation in flow-stimulated cells, highlighting a shift toward flat-to-curved clathrin transitions in vesicle formation. Overall, our findings indicate that clathrin dynamics and CCV formation can be modulated by the local physiological environment and represents an important regulatory mechanism.
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Affiliation(s)
- Tomasz J. Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Elizabeth Sztul
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexa L. Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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Puchkov D, Müller PM, Lehmann M, Matthaeus C. Analyzing the cellular plasma membrane by fast and efficient correlative STED and platinum replica EM. Front Cell Dev Biol 2023; 11:1305680. [PMID: 38099299 PMCID: PMC10720448 DOI: 10.3389/fcell.2023.1305680] [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: 10/02/2023] [Accepted: 11/13/2023] [Indexed: 12/17/2023] Open
Abstract
The plasma membrane of mammalian cells links transmembrane receptors, various structural components, and membrane-binding proteins to subcellular processes, allowing inter- and intracellular communication. Therefore, membrane-binding proteins, together with structural components such as actin filaments, modulate the cell membrane in their flexibility, stiffness, and curvature. Investigating membrane components and curvature in cells remains challenging due to the diffraction limit in light microscopy. Preparation of 5-15-nm-thin plasma membrane sheets and subsequent inspection by metal replica transmission electron microscopy (TEM) reveal detailed information about the cellular membrane topology, including the structure and curvature. However, electron microscopy cannot identify proteins associated with specific plasma membrane domains. Here, we describe a novel adaptation of correlative super-resolution light microscopy and platinum replica TEM (CLEM-PREM), allowing the analysis of plasma membrane sheets with respect to their structural details, curvature, and associated protein composition. We suggest a number of shortcuts and troubleshooting solutions to contemporary PREM protocols. Thus, implementation of super-resolution stimulated emission depletion (STED) microscopy offers significant reduction in sample preparation time and reduced technical challenges for imaging and analysis. Additionally, highly technical challenges associated with replica preparation and transfer on a TEM grid can be overcome by scanning electron microscopy (SEM) imaging. The combination of STED microscopy and platinum replica SEM or TEM provides the highest spatial resolution of plasma membrane proteins and their underlying membrane and is, therefore, a suitable method to study cellular events like endocytosis, membrane trafficking, or membrane tension adaptations.
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Affiliation(s)
- Dmytro Puchkov
- Cellular Imaging Facility, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Paul Markus Müller
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Martin Lehmann
- Cellular Imaging Facility, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Claudia Matthaeus
- Cellular Physiology of Nutrition, Institute for Nutritional Science, University of Potsdam, Potsdam, Germany
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