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Wu X, Hu JJ, Yoon J. Cell Membrane as A Promising Therapeutic Target: From Materials Design to Biomedical Applications. Angew Chem Int Ed Engl 2024; 63:e202400249. [PMID: 38372669 DOI: 10.1002/anie.202400249] [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: 01/04/2024] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 02/20/2024]
Abstract
The cell membrane is a crucial component of cells, protecting their integrity and stability while facilitating signal transduction and information exchange. Therefore, disrupting its structure or impairing its functions can potentially cause irreversible cell damage. Presently, the tumor cell membrane is recognized as a promising therapeutic target for various treatment methods. Given the extensive research focused on cell membranes, it is both necessary and timely to discuss these developments, from materials design to specific biomedical applications. This review covers treatments based on functional materials targeting the cell membrane, ranging from well-known membrane-anchoring photodynamic therapy to recent lysosome-targeting chimaeras for protein degradation. The diverse therapeutic mechanisms are introduced in the following sections: membrane-anchoring phototherapy, self-assembly on the membrane, in situ biosynthesis on the membrane, and degradation of cell membrane proteins by chimeras. In each section, we outline the conceptual design or general structure derived from numerous studies, emphasizing representative examples to understand advancements and draw inspiration. Finally, we discuss some challenges and future directions in membrane-targeted therapy from our perspective. This review aims to engage multidisciplinary readers and encourage researchers in related fields to advance the fundamental theories and practical applications of membrane-targeting therapeutic agents.
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Affiliation(s)
- Xiaofeng Wu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, 210096, Nanjing, China
| | - Jing-Jing Hu
- State Key Laboratory of Biogeology Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, 430074, Wuhan, China
- Department of Chemistry and Nanoscience, Ewha Womans University, 03706, Seoul, Republic of Korea
| | - Juyoung Yoon
- Department of Chemistry and Nanoscience, Ewha Womans University, 03706, Seoul, Republic of Korea
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Bittel DC, Jaiswal JK. Early Endosomes Undergo Calcium-Triggered Exocytosis and Enable Repair of Diffuse and Focal Plasma Membrane Injury. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300245. [PMID: 37705135 PMCID: PMC10667805 DOI: 10.1002/advs.202300245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/27/2023] [Indexed: 09/15/2023]
Abstract
Cells are routinely exposed to agents that cause plasma membrane (PM) injury. While pore-forming toxins (PFTs), and chemicals cause nanoscale holes dispersed throughout the PM, mechanical trauma causes focal lesions in the PM. To examine if these distinct injuries share common repair mechanism, membrane trafficking is monitored as the PM repairs from such injuries. During the course of repair, dispersed PM injury by the PFT Streptolysin O activates endocytosis, while focal mechanical injury to the PM inhibits endocytosis. Consequently, acute block of endocytosis prevents repair of diffuse, but not of focal injury. In contrast, a chronic block in endocytosis depletes cells of early endosomes and inhibits repair of focal injury. This study finds that both focal and diffuse PM injury activate Ca2+ -triggered exocytosis of early endosomes. The use of markers including endocytosed cargo, Rab5, Rab11, and VAMP3, all reveal injury-triggered exocytosis of early endosomes. Inhibiting Rab5 prevents injury-triggered early endosome exocytosis and phenocopies the failed PM repair of cells chronically depleted of early endosomes. These results identify early endosomes as a Ca2+ -regulated exocytic compartment, and uncover the requirement of their dual functions - endocytosis and regulated exocytosis, to differentially support PM repair based on the nature of the injury.
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Affiliation(s)
- Daniel C. Bittel
- Center for Genetic Medicine ResearchChildren's National Research Institute7144 13th Pl NWWashington, DC20012USA
| | - Jyoti K. Jaiswal
- Center for Genetic Medicine ResearchChildren's National Research Institute7144 13th Pl NWWashington, DC20012USA
- Department of Genomics and Precision MedicineGeorge Washington University School of Medicine and Health SciencesWashington, DC20012USA
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Zhang Y, Su M, Fang X, Huang W, Jiang H, Li Q, Hussain N, Ye M, Liu H, Tan W. Single-nucleobase resolution of a surface energy transfer nanoruler for in situ measurement of aptamer binding at the receptor subunit level in living cells. Chem Sci 2023; 14:9560-9573. [PMID: 37712043 PMCID: PMC10498721 DOI: 10.1039/d3sc01244a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 08/16/2023] [Indexed: 09/16/2023] Open
Abstract
In situ identification of aptamer-binding targets on living cell membrane surfaces is of considerable interest, but a major challenge, specifically, when advancing recognition to the level of membrane receptor subunits. Here we propose a novel nanometal surface energy transfer (NSET) based nanoruler with a single-nucleobase resolution (SN-nanoruler), in which FAM-labeled aptamers and single-sized gold nanoparticle (GNP) antibody conjugates act as a donor and an acceptor. A single nucleobase resolution of the SN-nanoruler was experimentally illustrated by molecular size, orientation, quenching nature, and other dye-GNP pairs. The SN-nanoruler provides high reproducibility and precision for measuring molecule distance on living cell membranes at the nanometer level owing to only the use of single-sized antibody-capped GNPs. In situ identification of the aptamer binding site was advanced to the protein subunit level on the living cell membrane for the utilization of this SN-nanoruler. The results suggest that the proposed strategy is a solid step towards the wider application of optical-based rulers to observe the molecular structural configuration and dynamic transitions on the membrane surface of living cells.
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Affiliation(s)
- Yu Zhang
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Mengke Su
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Xingru Fang
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Wenwen Huang
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Hao Jiang
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Qi Li
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Nisar Hussain
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
| | - Mao Ye
- Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Material Science and Engineering, College of Chemistry and Chemical Engineering, College of Biology, Hunan University Changsha 410082 China
| | - Honglin Liu
- China Light Industry Key Laboratory of Meat Microbial Control and Utilization, School of Food and Biological Engineering, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology Hefei 230601 P. R. China
- Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Material Science and Engineering, College of Chemistry and Chemical Engineering, College of Biology, Hunan University Changsha 410082 China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Material Science and Engineering, College of Chemistry and Chemical Engineering, College of Biology, Hunan University Changsha 410082 China
- The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences Hangzhou Zhejiang 310022 China
- Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University Shanghai 200240 China
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McAffee DB, O’Dair MK, Lin JJ, Low-Nam ST, Wilhelm KB, Kim S, Morita S, Groves JT. Discrete LAT condensates encode antigen information from single pMHC:TCR binding events. Nat Commun 2022; 13:7446. [PMID: 36460640 PMCID: PMC9718779 DOI: 10.1038/s41467-022-35093-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022] Open
Abstract
LAT assembly into a two-dimensional protein condensate is a prominent feature of antigen discrimination by T cells. Here, we use single-molecule imaging techniques to resolve the spatial position and temporal duration of each pMHC:TCR molecular binding event while simultaneously monitoring LAT condensation at the membrane. An individual binding event is sufficient to trigger a LAT condensate, which is self-limiting, and neither its size nor lifetime is correlated with the duration of the originating pMHC:TCR binding event. Only the probability of the LAT condensate forming is related to the pMHC:TCR binding dwell time. LAT condenses abruptly, but after an extended delay from the originating binding event. A LAT mutation that facilitates phosphorylation at the PLC-γ1 recruitment site shortens the delay time to LAT condensation and alters T cell antigen specificity. These results identify a function for the LAT protein condensation phase transition in setting antigen discrimination thresholds in T cells.
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Affiliation(s)
- Darren B. McAffee
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Mark K. O’Dair
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Jenny J. Lin
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Shalini T. Low-Nam
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Kiera B. Wilhelm
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Sungi Kim
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Shumpei Morita
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA
| | - Jay T. Groves
- grid.47840.3f0000 0001 2181 7878Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720 USA ,grid.59025.3b0000 0001 2224 0361Institute for Digital Molecular Analytics and Science, Nanyang Technological University, 59 Nanyang Drive, Singapore, 636921 Singapore
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Liu R, Gao Y, Liu N, Suo Y. Nanoparticles loading porphyrin sensitizers in improvement of photodynamic therapy for ovarian cancer. Photodiagnosis Photodyn Ther 2020; 33:102156. [PMID: 33352314 DOI: 10.1016/j.pdpdt.2020.102156] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/15/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Ovarian cancer, the malignant tumor with the highest mortality rate in gynecological tumors, leads to a poor prognosis due to tumor metastasis. At present, the main treatment for ovarian cancer is the combination of cytoreduction surgery and chemotherapy. But the surgery is insufficient to solve the extensive transfer of tumor in the abdominal cavity and a large proportion of ovarian cancer cases have shown resistance to chemotherapy. Photodynamic therapy (PDT) is a viable treatment option for a wide range of applications, especially in malignant tumors. Porphyrin sensitizers, as the most widely used photosensitive agents, have the following advantages: short photosensitive period and high singlet oxygen production. However, most studies have found that it is difficult to achieve high loading rates of photosensitive agents, thus effective concentration in target tissue is suboptimal and the lethal ability is greatly reduced. In this article, we review several studies that nanoparticles loading porphyrin sensitizers for photodynamic therapy of ovarian cancer. METHODS We collected relevant literature from PUBMED and reviewed their research content. RESULTS The application of nanotechnology to PDT in ovarian cancer can reduce the non-specific toxicity of photosensitive agents and increase stability and delivery efficiency. CONCLUSIONS The combination with nanotechnology can cover the shortcomings of photodynamic therapy, but the specific efficacy still needs a large number of experiments to prove.
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Affiliation(s)
- Rui Liu
- Obstetrics and Gynaecology, Shanxi Provincial Peoples Hospital, Taiyuan, China.
| | - Yanxia Gao
- Obstetrics and Gynaecology, Shanxi Provincial Peoples Hospital, Taiyuan, China.
| | - Nannan Liu
- Obstetrics and Gynaecology, Shanxi Provincial Peoples Hospital, Taiyuan, China.
| | - Yuping Suo
- Obstetrics and Gynaecology, Shanxi Provincial Peoples Hospital, Taiyuan, China.
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Bittel DC, Chandra G, Tirunagri LMS, Deora AB, Medikayala S, Scheffer L, Defour A, Jaiswal JK. Annexin A2 Mediates Dysferlin Accumulation and Muscle Cell Membrane Repair. Cells 2020; 9:cells9091919. [PMID: 32824910 PMCID: PMC7565960 DOI: 10.3390/cells9091919] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/03/2020] [Accepted: 08/11/2020] [Indexed: 01/08/2023] Open
Abstract
Muscle cell plasma membrane is frequently damaged by mechanical activity, and its repair requires the membrane protein dysferlin. We previously identified that, similar to dysferlin deficit, lack of annexin A2 (AnxA2) also impairs repair of skeletal myofibers. Here, we have studied the mechanism of AnxA2-mediated muscle cell membrane repair in cultured muscle cells. We find that injury-triggered increase in cytosolic calcium causes AnxA2 to bind dysferlin and accumulate on dysferlin-containing vesicles as well as with dysferlin at the site of membrane injury. AnxA2 accumulates on the injured plasma membrane in cholesterol-rich lipid microdomains and requires Src kinase activity and the presence of cholesterol. Lack of AnxA2 and its failure to translocate to the plasma membrane, both prevent calcium-triggered dysferlin translocation to the plasma membrane and compromise repair of the injured plasma membrane. Our studies identify that Anx2 senses calcium increase and injury-triggered change in plasma membrane cholesterol to facilitate dysferlin delivery and repair of the injured plasma membrane.
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Affiliation(s)
- Daniel C. Bittel
- Center for Genetic Medicine Research, 111 Michigan Av NW, Children’s National Hospital, Washington, DC 20010, USA; (D.C.B.); (G.C.); (S.M.); (L.S.); (A.D.)
| | - Goutam Chandra
- Center for Genetic Medicine Research, 111 Michigan Av NW, Children’s National Hospital, Washington, DC 20010, USA; (D.C.B.); (G.C.); (S.M.); (L.S.); (A.D.)
| | - Laxmi M. S. Tirunagri
- Department of Cellular Biophysics, The Rockefeller University, New York, NY 10065, USA;
| | - Arun B. Deora
- Department of Cell & Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA;
| | - Sushma Medikayala
- Center for Genetic Medicine Research, 111 Michigan Av NW, Children’s National Hospital, Washington, DC 20010, USA; (D.C.B.); (G.C.); (S.M.); (L.S.); (A.D.)
| | - Luana Scheffer
- Center for Genetic Medicine Research, 111 Michigan Av NW, Children’s National Hospital, Washington, DC 20010, USA; (D.C.B.); (G.C.); (S.M.); (L.S.); (A.D.)
| | - Aurelia Defour
- Center for Genetic Medicine Research, 111 Michigan Av NW, Children’s National Hospital, Washington, DC 20010, USA; (D.C.B.); (G.C.); (S.M.); (L.S.); (A.D.)
| | - Jyoti K. Jaiswal
- Center for Genetic Medicine Research, 111 Michigan Av NW, Children’s National Hospital, Washington, DC 20010, USA; (D.C.B.); (G.C.); (S.M.); (L.S.); (A.D.)
- Department of Genomics and Precision medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
- Correspondence: ; Tel.: +1-(202)476-6456; Fax: +1-(202)476-6014
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Wong WC, Juo JY, Lin CH, Liao YH, Cheng CY, Hsieh CL. Characterization of Single-Protein Dynamics in Polymer-Cushioned Lipid Bilayers Derived from Cell Plasma Membranes. J Phys Chem B 2019; 123:6492-6504. [DOI: 10.1021/acs.jpcb.9b03789] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wai Cheng Wong
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
| | - Jz-Yuan Juo
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
| | - Chih-Hsiang Lin
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
| | - Yi-Hung Liao
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
| | - Ching-Ya Cheng
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
| | - Chia-Lung Hsieh
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei 10617, Taiwan
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Pandey V, Gupta S, Elangovan R. Compact 3D printed module for fluorescence and label-free imaging using evanescent excitation. Methods Appl Fluoresc 2017; 6:015007. [PMID: 29076809 DOI: 10.1088/2050-6120/aa967a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Total internal reflection fluorescence (TIRF) microscopy is widely used for selective excitation and high-resolution imaging of fluorophores, and more recently label-free nanosized objects, with high vertical confinement near a liquid-solid interface. Traditionally, high numerical aperture objectives (>1.4) are used to simultaneously generate evanescent waves and collect fluorescence emission signals which limits their use to small area imaging (<0.1 mm2). Objective-based TIRFs are also expensive as they require dichroic mirrors and efficient notch filters to prevent specular reflection within the objective lenses. We have developed a compact 3D module called cTIRF that can generate evanescent waves in microscope glass slides via a planar waveguide illumination. The module can be attached as a fixture to any existing optical microscope, converting it into a TIRF and enabling high signal-to-noise ratio (SNR) fluorescence imaging using any magnification objective. As the incidence optics is perpendicular to the detector, label-free evanescent scattering-based imaging of submicron objects can also be performed without using emission filters. SNR is significantly enhanced in this case as compared to cTIRF alone, as seen through our model experiments performed on latex beads and mammalian cells. Extreme flexibility and the low cost of our approach makes it scalable for limited resource settings.
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Affiliation(s)
- Vikas Pandey
- Department of Chemical Engineering, Indian Institute of Technology, Delhi, 110016, India
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Wu Y, Zeng G, Lvyue N, Wu W, Jiang T, Wu R, Guo W, Li X, Fan X. Triethylene glycol-modified iridium(iii) complexes for fluorescence imaging of Schistosoma japonicum. J Mater Chem B 2017; 5:4973-4980. [PMID: 32264013 DOI: 10.1039/c7tb00662d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Schistosomiasis, an infectious disease caused by the Schistosoma parasitic worm, presents a serious public health issue. To date, investigation of anti-Schistosomiasis drug mechanisms through fluorescence imaging remains challenging due to the lack of appropriate dyes as fluorescent probes. Phosphorescent Ir(iii) complexes have been attracting substantial attention among various classes of fluorophores given their excellent photophysical properties. Herein, four phosphorescent Ir(iii) complexes were synthesized, two of which contained a triethylene glycol (TEG) hydrophilic group. The phosphorescent emission range of the four complexes lay between 500 and 750 nm, and their quantum yields ranged from 0.031 to 0.146. Furthermore, under the experimental concentration conditions, the TEG-modified complexes had low cytotoxicity. Cell fluorescence labeling experiments indicated that the TEG-modified complexes had good membrane permeability. Finally, the TEG-modified complexes showed remarkable labeling effects in adult Schistosoma fluorescence imaging. Thus, TEG-modified Ir(iii) complexes could be used as a new class of bilharzial fluorescent probes.
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Affiliation(s)
- Yongquan Wu
- School of Chemistry and Chemical Engineering & Key Laboratory of Organo-pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou, Jiangxi 341000, P. R. China.
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Buscemi L, Ginet V, Lopatar J, Montana V, Pucci L, Spagnuolo P, Zehnder T, Grubišić V, Truttman A, Sala C, Hirt L, Parpura V, Puyal J, Bezzi P. Homer1 Scaffold Proteins Govern Ca2+ Dynamics in Normal and Reactive Astrocytes. Cereb Cortex 2017; 27:2365-2384. [PMID: 27075036 PMCID: PMC5963825 DOI: 10.1093/cercor/bhw078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In astrocytes, the intracellular calcium (Ca2+) signaling mediated by activation of metabotropic glutamate receptor 5 (mGlu5) is crucially involved in the modulation of many aspects of brain physiology, including gliotransmission. Here, we find that the mGlu5-mediated Ca2+ signaling leading to release of glutamate is governed by mGlu5 interaction with Homer1 scaffolding proteins. We show that the long splice variants Homer1b/c are expressed in astrocytic processes, where they cluster with mGlu5 at sites displaying intense local Ca2+ activity. We show that the structural and functional significance of the Homer1b/c-mGlu5 interaction is to relocate endoplasmic reticulum (ER) to the proximity of the plasma membrane and to optimize Ca2+ signaling and glutamate release. We also show that in reactive astrocytes the short dominant-negative splice variant Homer1a is upregulated. Homer1a, by precluding the mGlu5-ER interaction decreases the intensity of Ca2+ signaling thus limiting the intensity and the duration of glutamate release by astrocytes. Hindering upregulation of Homer1a with a local injection of short interfering RNA in vivo restores mGlu5-mediated Ca2+ signaling and glutamate release and sensitizes astrocytes to apoptosis. We propose that Homer1a may represent one of the cellular mechanisms by which inflammatory astrocytic reactions are beneficial for limiting brain injury.
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Affiliation(s)
- Lara Buscemi
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Vanessa Ginet
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Jan Lopatar
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Vedrana Montana
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Luca Pucci
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Paola Spagnuolo
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Tamara Zehnder
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Vladimir Grubišić
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Anita Truttman
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Carlo Sala
- CNR Institute of Neuroscience and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Lorenz Hirt
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Paola Bezzi
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
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Bhatia D, Arumugam S, Nasilowski M, Joshi H, Wunder C, Chambon V, Prakash V, Grazon C, Nadal B, Maiti PK, Johannes L, Dubertret B, Krishnan Y. Quantum dot-loaded monofunctionalized DNA icosahedra for single-particle tracking of endocytic pathways. NATURE NANOTECHNOLOGY 2016; 11:1112-1119. [PMID: 27548358 PMCID: PMC5122452 DOI: 10.1038/nnano.2016.150] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/15/2016] [Indexed: 05/07/2023]
Abstract
Functionalization of quantum dots (QDs) with a single biomolecular tag using traditional approaches in bulk solution has met with limited success. DNA polyhedra consist of an internal void bounded by a well-defined three-dimensional structured surface. The void can house cargo and the surface can be functionalized with stoichiometric and spatial precision. Here, we show that monofunctionalized QDs can be realized by encapsulating QDs inside DNA icosahedra and functionalizing the DNA shell with an endocytic ligand. We deployed the DNA-encapsulated QDs for real-time imaging of three different endocytic ligands-folic acid, galectin-3 (Gal3) and the Shiga toxin B-subunit (STxB). Single-particle tracking of Gal3- or STxB-functionalized QD-loaded DNA icosahedra allows us to monitor compartmental dynamics along endocytic pathways. These DNA-encapsulated QDs, which bear a unique stoichiometry of endocytic ligands, represent a new class of molecular probes for quantitative imaging of endocytic receptor dynamics.
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Affiliation(s)
- Dhiraj Bhatia
- Chemical Biology of Membranes and Therapeutic Delivery unit, Institut Curie, PSL Research University, Institut national de la santé et de la recherche médicale, U 1143, Centre national de la recherche scientifique, Unité mixte de recherche 3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Gandhi Krishi Vigyan Kendra, Bellary Road, Bangalore 560065, India
| | - Senthil Arumugam
- Chemical Biology of Membranes and Therapeutic Delivery unit, Institut Curie, PSL Research University, Institut national de la santé et de la recherche médicale, U 1143, Centre national de la recherche scientifique, Unité mixte de recherche 3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Michel Nasilowski
- Laboratoire Physique et Etude des Matériaux UMR8213 École Supérieure de Physique et de Chimie Industrielles ParisTech-CNRS - Université Pierre et Marie Curie Sorbonne Universités 10 rue Vauquelin, 75005 Paris, France
| | - Himanshu Joshi
- Department of Physics, Center for Condensed Matter Theory, Indian Institute of Science, Bangalore 560012, India
| | - Christian Wunder
- Chemical Biology of Membranes and Therapeutic Delivery unit, Institut Curie, PSL Research University, Institut national de la santé et de la recherche médicale, U 1143, Centre national de la recherche scientifique, Unité mixte de recherche 3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Valérie Chambon
- Chemical Biology of Membranes and Therapeutic Delivery unit, Institut Curie, PSL Research University, Institut national de la santé et de la recherche médicale, U 1143, Centre national de la recherche scientifique, Unité mixte de recherche 3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Ved Prakash
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Gandhi Krishi Vigyan Kendra, Bellary Road, Bangalore 560065, India
- Department of Chemistry, The University of Chicago, 929 E, 57th Street, Chicago, Illinois 60637, USA
| | | | - Brice Nadal
- Nexdot, 10 rue Vauquelin, 75005 Paris, France
| | - Prabal K Maiti
- Department of Physics, Center for Condensed Matter Theory, Indian Institute of Science, Bangalore 560012, India
| | - Ludger Johannes
- Chemical Biology of Membranes and Therapeutic Delivery unit, Institut Curie, PSL Research University, Institut national de la santé et de la recherche médicale, U 1143, Centre national de la recherche scientifique, Unité mixte de recherche 3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Benoit Dubertret
- Laboratoire Physique et Etude des Matériaux UMR8213 École Supérieure de Physique et de Chimie Industrielles ParisTech-CNRS - Université Pierre et Marie Curie Sorbonne Universités 10 rue Vauquelin, 75005 Paris, France
| | - Yamuna Krishnan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Gandhi Krishi Vigyan Kendra, Bellary Road, Bangalore 560065, India
- Department of Chemistry, The University of Chicago, 929 E, 57th Street, Chicago, Illinois 60637, USA
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, 5812 South Ellis Avenue, Chicago, Illinois 60637, USA
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12
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Li X, Xing J, Qiu Z, He Q, Lin J. Quantification of Membrane Protein Dynamics and Interactions in Plant Cells by Fluorescence Correlation Spectroscopy. MOLECULAR PLANT 2016; 9:1229-1239. [PMID: 27381442 DOI: 10.1016/j.molp.2016.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/25/2016] [Accepted: 06/27/2016] [Indexed: 05/25/2023]
Abstract
Deciphering the dynamics of protein and lipid molecules on appropriate spatial and temporal scales may shed light on protein function and membrane organization. However, traditional bulk approaches cannot unambiguously quantify the extremely diverse mobility and interactions of proteins in living cells. Fluorescence correlation spectroscopy (FCS) is a powerful technique to describe events that occur at the single-molecule level and on the nanosecond to second timescales; therefore, FCS can provide data on the heterogeneous organization of membrane systems. FCS can also be combined with other microscopy techniques, such as super-resolution techniques. More importantly, FCS is minimally invasive, which makes it an ideal approach to detect the heterogeneous distribution and dynamics of key proteins during development. In this review, we give a brief introduction about the development of FCS and summarize the significant contributions of FCS in understanding the organization of plant cell membranes and the dynamics and interactions of membrane proteins. We also discuss the potential applications of this technique in plant biology.
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Affiliation(s)
- Xiaojuan Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Jingjing Xing
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 10049, China
| | - Zongbo Qiu
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Qihua He
- The Health Science Center, Peking University, Beijing 100191, China
| | - Jinxing Lin
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China.
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13
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Qiu F, Huang Y, Zhu X. Fluorescent Unimolecular Conjugated Polymeric Micelles for Biological Applications. MACROMOL CHEM PHYS 2015. [DOI: 10.1002/macp.201500283] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Feng Qiu
- School of Chemical and Environmental Engineering; Shanghai Institute of Technology; 100 Haiquan Road Shanghai 201418 P. R. China
| | - Yu Huang
- School of Chemistry and Chemical Engineering; State Key Laboratory of Metal Matrix Composites; Shanghai Jiao Tong University; 800 Dongchuan Road Shanghai 200240 P. R. China
| | - Xinyuan Zhu
- School of Chemistry and Chemical Engineering; State Key Laboratory of Metal Matrix Composites; Shanghai Jiao Tong University; 800 Dongchuan Road Shanghai 200240 P. R. China
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14
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Sreetama SC, Takano T, Nedergaard M, Simon SM, Jaiswal JK. Injured astrocytes are repaired by Synaptotagmin XI-regulated lysosome exocytosis. Cell Death Differ 2015; 23:596-607. [PMID: 26450452 DOI: 10.1038/cdd.2015.124] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 08/03/2015] [Accepted: 08/17/2015] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are known to facilitate repair following brain injury; however, little is known about how injured astrocytes repair themselves. Repair of cell membrane injury requires Ca(2+)-triggered vesicle exocytosis. In astrocytes, lysosomes are the main Ca(2+)-regulated exocytic vesicles. Here we show that astrocyte cell membrane injury results in a large and rapid calcium increase. This triggers robust lysosome exocytosis where the fusing lysosomes release all luminal contents and merge fully with the plasma membrane. In contrast to this, receptor stimulation produces a small sustained calcium increase, which is associated with partial release of the lysosomal luminal content, and the lysosome membrane does not merge into the plasma membrane. In most cells, lysosomes express the synaptotagmin (Syt) isoform Syt VII; however, this isoform is not present on astrocyte lysosomes and exogenous expression of Syt VII on lysosome inhibits their exocytosis. Deletion of one of the most abundant Syt isoform in astrocyte--Syt XI--suppresses astrocyte lysosome exocytosis. This identifies lysosome as Syt XI-regulated exocytic vesicle in astrocytes. Further, inhibition of lysosome exocytosis (by Syt XI depletion or Syt VII expression) prevents repair of injured astrocytes. These results identify the lysosomes and Syt XI as the sub-cellular and molecular regulators, respectively of astrocyte cell membrane repair.
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Affiliation(s)
- S C Sreetama
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - T Takano
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - M Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - S M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, USA
| | - J K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue NW, Washington, DC, USA
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15
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Cosentino K, Ros U, García-Sáez AJ. Assembling the puzzle: Oligomerization of α-pore forming proteins in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:457-466. [PMID: 26375417 DOI: 10.1016/j.bbamem.2015.09.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/26/2015] [Accepted: 09/09/2015] [Indexed: 12/21/2022]
Abstract
Pore forming proteins (PFPs) share the ability of creating pores that allow the passage of ions, proteins or other constituents through a wide variety of target membranes, ranging from bacteria to humans. They often cause cell death, as pore formation disrupts the membrane permeability barrier required for maintaining cell homeostasis. The organization into supramolecular complexes or oligomers that pierce the membrane is a common feature of PFPs. However, the molecular pathway of self-assembly and pore opening remains unclear. Here, we review the most recent discoveries in the mechanism of membrane oligomerization and pore formation of a subset of PFPs, the α-PFPs, whose pore-forming domains are formed by helical segments. Only now we are starting to grasp the molecular details of their function, mainly thanks to the introduction of single molecule microscopy and nanoscopy techniques. This article is part of a Special Issue entitled: Pore-forming toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Katia Cosentino
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Uris Ros
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany.,Center for Protein Studies, Havana University, Havana, Cuba
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
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16
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Wang L, Li H, Lv X, Chen T, Li R, Xue Y, Jiang J, Jin B, Baluška F, Šamaj J, Wang X, Lin J. Spatiotemporal Dynamics of the BRI1 Receptor and its Regulation by Membrane Microdomains in Living Arabidopsis Cells. MOLECULAR PLANT 2015; 8:1334-49. [PMID: 25896454 DOI: 10.1016/j.molp.2015.04.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 04/10/2015] [Accepted: 04/12/2015] [Indexed: 05/22/2023]
Abstract
The major brassinosteroid (BR) receptor of Arabidopsis BRASSINOSTEROID INSENSITIVE1 (BRI1) plays fundamental roles in BR signaling, but the molecular mechanisms underlying the effects of BR on BRI1 internalization and assembly state remain unclear. Here, we applied variable angle total internal reflection fluorescence microscopy and fluorescence cross-correlation spectroscopy to analyze the dynamics of GFP-tagged BRI1. We found that, in response to BR, the degree of co-localization of BRI1-GFP with AtFlot1-mCherry increased, and especially BR stimulated the membrane microdomain-associated pathway of BRI1 internalization. We also verified these observations in endocytosis-defective chc2-1 mutants and the AtFlot1 amiRNA 15-5 lines. Furthermore, examination of the phosphorylation status of bri1-EMS-suppressor 1 and measurement of BR-responsive gene expression revealed that membrane microdomains affect BR signaling. These results suggest that BR promotes the partitioning of BRI1 into functional membrane microdomains to activate BR signaling.
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Affiliation(s)
- Li Wang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Hong Li
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Xueqin Lv
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Tong Chen
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ruili Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Yiqun Xue
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jianjun Jiang
- State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Biao Jin
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
| | - Jozef Šamaj
- Department of Cell Biology, Palacky University Olomouc, Olomouc 78371, Czech Republic
| | - Xuelu Wang
- State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China; College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinxing Lin
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China.
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17
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Wang S, Kaartinen MT. Cellular Factor XIIIA Transglutaminase Localizes in Caveolae and Regulates Caveolin-1 Phosphorylation, Homo-oligomerization and c-Src Signaling in Osteoblasts. J Histochem Cytochem 2015; 63:829-41. [PMID: 26231113 DOI: 10.1369/0022155415597964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 07/05/2015] [Indexed: 11/22/2022] Open
Abstract
Transglutaminases (TGs) are a family of widely distributed enzymes that catalyze protein crosslinking by forming a covalent isopeptide bond between the substrate proteins. We have shown that MC3T3-E1 osteoblasts express Factor XIII-A (FXIII-A), and that the extracellular crosslinking activity of FXIII-A is involved in regulating matrix secretion and deposition. In this study, we have investigated the localization and potential role of intracellular FXIII-A. Conventional immunofluorescence microscopy and TIRF microscopy analyses showed that FXIII-A co-localizes with caveolin-1 in specialized membrane structures, caveolae, in differentiating osteoblasts. The caveolae-disrupting agent methyl-β-cyclodextrin abolished FXIII-A staining and co-localization with caveolin-1 from the osteoblast plasma membrane. The presence of FXIII-A in caveolae was confirmed by preparing caveolae-enriched cellular fractions using sucrose density gradient ultracentrifugation followed by western blotting. Despite this association of FXIII-A with caveolae, there was no detectable transglutaminase activity in caveolae, as measured by monodansylcadaverine incorporation. TG inhibitor NC9--which can alter TG enzyme conformation--localized to caveolae and displaced FXIII-A from these structures when added to the osteoblast cultures. The decreased FXIII-A levels in caveolae after NC9 treatment increased c-Src activation, which resulted in caveolin-1 phosphorylation, homo-oligomerization and Akt phosphorylation, suggesting cellular FXIII-A has a role in regulating c-Src signaling in osteoblasts.
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Affiliation(s)
- Shuai Wang
- Division of Biomedical Sciences, Faculty of Dentistry, McGill University, Montreal, QC, Canada. (SW, MTK)
| | - Mari T Kaartinen
- Division of Experimental Medicine, Department of Medicine, Faculty of Medicine, McGill University, Montreal, QC, Canada (MTK),Division of Biomedical Sciences, Faculty of Dentistry, McGill University, Montreal, QC, Canada. (SW, MTK)
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18
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Zhang J, Liu K, Müllen K, Yin M. Self-assemblies of amphiphilic homopolymers: synthesis, morphology studies and biomedical applications. Chem Commun (Camb) 2015; 51:11541-55. [DOI: 10.1039/c5cc03016a] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The need for a simplified access to supramolecular assemblies with enhanced tenability has led to the development of amphiphilic homopolymers (APHPs). This review highlights recent advances and future trends in APHP design, self-assembly, and biomedical applications.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Chemical Resource Engineering
- Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education
- Beijing Laboratory of Biomedical Materials
- Beijing University of Chemical Technology
- 100029 Beijing
| | - Kelan Liu
- State Key Laboratory of Chemical Resource Engineering
- Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education
- Beijing Laboratory of Biomedical Materials
- Beijing University of Chemical Technology
- 100029 Beijing
| | - Klaus Müllen
- Max-Planck-Institute for Polymer Research
- 55128 Mainz
- Germany
| | - Meizhen Yin
- State Key Laboratory of Chemical Resource Engineering
- Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education
- Beijing Laboratory of Biomedical Materials
- Beijing University of Chemical Technology
- 100029 Beijing
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19
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Roman-Vendrell C, Chevalier M, Acevedo-Canabal AM, Delgado-Peraza F, Flores-Otero J, Yudowski GA. Imaging of kiss-and-run exocytosis of surface receptors in neuronal cultures. Front Cell Neurosci 2014; 8:363. [PMID: 25404895 PMCID: PMC4217495 DOI: 10.3389/fncel.2014.00363] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 10/14/2014] [Indexed: 02/01/2023] Open
Abstract
Transmembrane proteins are continuously shuttled from the endosomal compartment to the neuronal plasma membrane by highly regulated and complex trafficking steps. These events are involved in many homeostatic and physiological processes such as neuronal growth, signaling, learning and memory among others. We have previously shown that endosomal exocytosis of the B2 adrenergic receptor (B2AR) and the GluR1-containing AMPA receptor to the neuronal plasma membrane is mediated by two different types of vesicular fusion. A rapid type of exocytosis in which receptors are delivered to the plasma membrane in a single kinetic step, and a persistent mode in which receptors remain clustered at the insertion site for a variable period of time before delivery to the cell surface. Here, by comparing the exocytosis of multiple receptors in dissociated hippocampal and striatal cultures, we show that persistent events are a general mechanism of vesicular delivery. Persistent events were only observed after 10 days in vitro, and their frequency increased with use of the calcium ionophore A23187 and with depolarization induced by KCl. Finally, we determined that vesicles producing persistent events remain at the plasma membrane, closing and reopening their fusion pore for a consecutive release of cargo in a mechanism reminiscent of synaptic kiss-and-run. These results indicate that the delivery of transmembrane receptors to the cell surface can be dynamically regulated by kiss-and-run exocytosis.
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Affiliation(s)
- Cristina Roman-Vendrell
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus San Juan, PR, USA ; Department of Physiology, School of Medicine, University of Puerto Rico San Juan, PR, USA
| | - Michael Chevalier
- Department of Biochemistry and Biophysics, California Institute for Quantitative Biosciences, University of California San Francisco San Francisco, CA, USA
| | - Agnes M Acevedo-Canabal
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus San Juan, PR, USA ; Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico San Juan, PR, USA
| | - Francheska Delgado-Peraza
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus San Juan, PR, USA ; Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico San Juan, PR, USA
| | - Jacqueline Flores-Otero
- Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico San Juan, PR, USA
| | - Guillermo A Yudowski
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus San Juan, PR, USA ; Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico San Juan, PR, USA
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20
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Carvalho PHPR, Correa JR, Guido BC, Gatto CC, De Oliveira HCB, Soares TA, Neto BAD. Designed Benzothiadiazole Fluorophores for Selective Mitochondrial Imaging and Dynamics. Chemistry 2014; 20:15360-74. [DOI: 10.1002/chem.201404039] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Indexed: 11/06/2022]
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21
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Thuenauer R, Rodriguez-Boulan E, Römer W. Microfluidic approaches for epithelial cell layer culture and characterisation. Analyst 2014; 139:3206-18. [PMID: 24668405 PMCID: PMC4286366 DOI: 10.1039/c4an00056k] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In higher eukaryotes, epithelial cell layers line most body cavities and form selective barriers that regulate the exchange of solutes between compartments. In order to fulfil these functions, the cells assume a polarised architecture and maintain two distinct plasma membrane domains, the apical domain facing the lumen and the basolateral domain facing other cells and the extracellular matrix. Microfluidic biochips offer the unique opportunity to establish novel in vitro models of epithelia in which the in vivo microenvironment of epithelial cells is precisely reconstituted. In addition, analytical tools to monitor biologically relevant parameters can be directly integrated on-chip. In this review we summarise recently developed biochip designs for culturing epithelial cell layers. Since endothelial cell layers, which line blood vessels, have similar barrier functions and polar organisation as epithelial cell layers, we also discuss biochips for culturing endothelial cell layers. Furthermore, we review approaches to integrate tools to analyse and manipulate epithelia and endothelia in microfluidic biochips; including methods to perform electrical impedance spectroscopy; methods to detect substances undergoing trans-epithelial transport via fluorescence, spectrophotometry, and mass spectrometry; techniques to mechanically stimulate cells via stretching and fluid flow-induced shear stress; and methods to carry out high-resolution imaging of vesicular trafficking using light microscopy. Taken together, this versatile microfluidic toolbox enables novel experimental approaches to characterise epithelial monolayers.
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Affiliation(s)
- Roland Thuenauer
- Institute of Biology II, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany.
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22
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Abstract
A fundamental and still largely unresolved question is how neurons achieve rapid delivery of selected signaling receptors throughout the elaborate dendritic arbor. Here we show that this requires a conserved sorting machinery called retromer. Retromer-associated endosomes are distributed within dendrites in ∼2 μm intervals and supply frequent membrane fusion events into the dendritic shaft domain immediately adjacent to (<300 nm from) the donor endosome and typically without full endosome discharge. Retromer-associated endosomes contain β-adrenergic receptors as well as ionotropic glutamate receptors, and retromer knockdown reduces extrasynaptic insertion of adrenergic receptors as well as functional expression of AMPA and NMDA receptors at synapses. We propose that retromer supports a broadly distributed network of plasma membrane delivery to dendrites, organized in micron-scale axial territories to render essentially all regions of the postsynaptic surface within rapid diffusion distance of a local exocytic event.
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23
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Defour A, Sreetama SC, Jaiswal JK. Imaging cell membrane injury and subcellular processes involved in repair. J Vis Exp 2014:51106. [PMID: 24686523 PMCID: PMC4089398 DOI: 10.3791/51106] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The ability of injured cells to heal is a fundamental cellular process, but cellular and molecular mechanisms involved in healing injured cells are poorly understood. Here assays are described to monitor the ability and kinetics of healing of cultured cells following localized injury. The first protocol describes an end point based approach to simultaneously assess cell membrane repair ability of hundreds of cells. The second protocol describes a real time imaging approach to monitor the kinetics of cell membrane repair in individual cells following localized injury with a pulsed laser. As healing injured cells involves trafficking of specific proteins and subcellular compartments to the site of injury, the third protocol describes the use of above end point based approach to assess one such trafficking event (lysosomal exocytosis) in hundreds of cells injured simultaneously and the last protocol describes the use of pulsed laser injury together with TIRF microscopy to monitor the dynamics of individual subcellular compartments in injured cells at high spatial and temporal resolution. While the protocols here describe the use of these approaches to study the link between cell membrane repair and lysosomal exocytosis in cultured muscle cells, they can be applied as such for any other adherent cultured cell and subcellular compartment of choice.
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Affiliation(s)
- Aurelia Defour
- Center for Genetic Medicine Research, Children's National Medical Center
| | - S C Sreetama
- Center for Genetic Medicine Research, Children's National Medical Center
| | - Jyoti K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center; Department of Integrative Systems Biology, George Washington University;
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24
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Detyrosinated Glu-tubulin is a substrate for cellular Factor XIIIA transglutaminase in differentiating osteoblasts. Amino Acids 2014; 46:1513-26. [DOI: 10.1007/s00726-014-1719-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 02/26/2014] [Indexed: 11/26/2022]
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25
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Brunstein M, Hérault K, Oheim M. Eliminating unwanted far-field excitation in objective-type TIRF. Part II. combined evanescent-wave excitation and supercritical-angle fluorescence detection improves optical sectioning. Biophys J 2014; 106:1044-56. [PMID: 24606929 PMCID: PMC4026779 DOI: 10.1016/j.bpj.2013.12.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 12/29/2022] Open
Abstract
Azimuthal beam scanning makes evanescent-wave (EW) excitation isotropic, thereby producing total internal reflection fluorescence (TIRF) images that are evenly lit. However, beam spinning does not fundamentally address the problem of propagating excitation light that is contaminating objective-type TIRF. Far-field excitation depends more on the specific objective than on cell scattering. As a consequence, the excitation impurities in objective-type TIRF are only weakly affected by changes of azimuthal or polar beam angle. These are the main results of the first part of this study (Eliminating unwanted far-field excitation in objective-type TIRF. Pt.1. Identifying sources of nonevanescent excitation light). This second part focuses on exactly where up beam in the illumination system stray light is generated that gives rise to nonevanescent components in TIRF. Using dark-field imaging of scattered excitation light we pinpoint the objective, intermediate lenses and, particularly, the beam scanner as the major sources of stray excitation. We study how adhesion-molecule coating and astrocytes or BON cells grown on the coverslip surface modify the dark-field signal. On flat and weakly scattering cells, most background comes from stray reflections produced far from the sample plane, in the beam scanner and the objective lens. On thick, optically dense cells roughly half of the scatter is generated by the sample itself. We finally show that combining objective-type EW excitation with supercritical-angle fluorescence (SAF) detection efficiently rejects the fluorescence originating from deeper sample regions. We demonstrate that SAF improves the surface selectivity of TIRF, even at shallow penetration depths. The coplanar microscopy scheme presented here merges the benefits of beam spinning EW excitation and SAF detection and provides the conditions for quantitative wide-field imaging of fluorophore dynamics at or near the plasma membrane.
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Affiliation(s)
- Maia Brunstein
- CNRS, UMR 8154, Paris, F-75006 France; INSERM, U603, Paris, F-75006 France; Laboratoire de Neurophysiologie et Nouvelles Microscopies, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, F-75006 France
| | - Karine Hérault
- CNRS, UMR 8154, Paris, F-75006 France; INSERM, U603, Paris, F-75006 France; Laboratoire de Neurophysiologie et Nouvelles Microscopies, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, F-75006 France
| | - Martin Oheim
- CNRS, UMR 8154, Paris, F-75006 France; INSERM, U603, Paris, F-75006 France; Laboratoire de Neurophysiologie et Nouvelles Microscopies, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, F-75006 France.
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Four-dimensional live imaging of apical biosynthetic trafficking reveals a post-Golgi sorting role of apical endosomal intermediates. Proc Natl Acad Sci U S A 2014; 111:4127-32. [PMID: 24591614 DOI: 10.1073/pnas.1304168111] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Emerging data suggest that in polarized epithelial cells newly synthesized apical and basolateral plasma membrane proteins traffic through different endosomal compartments en route to the respective cell surface. However, direct evidence for trans-endosomal pathways of plasma membrane proteins is still missing and the mechanisms involved are poorly understood. Here, we imaged the entire biosynthetic route of rhodopsin-GFP, an apical marker in epithelial cells, synchronized through recombinant conditional aggregation domains, in live Madin-Darby canine kidney cells using spinning disk confocal microscopy. Our experiments directly demonstrate that rhodopsin-GFP traffics through apical recycling endosomes (AREs) that bear the small GTPase Rab11a before arriving at the apical membrane. Expression of dominant-negative Rab11a drastically reduced apical delivery of rhodopsin-GFP and caused its missorting to the basolateral membrane. Surprisingly, functional inhibition of dynamin-2 trapped rhodopsin-GFP at AREs and caused aberrant accumulation of coated vesicles on AREs, suggesting a previously unrecognized role for dynamin-2 in the scission of apical carrier vesicles from AREs. A second set of experiments, using a unique method to carry out total internal reflection fluorescence microscopy (TIRFM) from the apical side, allowed us to visualize the fusion of rhodopsin-GFP carrier vesicles, which occurred randomly all over the apical plasma membrane. Furthermore, two-color TIRFM showed that Rab11a-mCherry was present in rhodopsin-GFP carrier vesicles and was rapidly released upon fusion onset. Our results provide direct evidence for a role of AREs as a post-Golgi sorting hub in the biosynthetic route of polarized epithelia, with Rab11a regulating cargo sorting at AREs and carrier vesicle docking at the apical membrane.
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Noam Y, Ehrengruber MU, Koh A, Feyen P, Manders EMM, Abbott GW, Wadman WJ, Baram TZ. Filamin A promotes dynamin-dependent internalization of hyperpolarization-activated cyclic nucleotide-gated type 1 (HCN1) channels and restricts Ih in hippocampal neurons. J Biol Chem 2014; 289:5889-903. [PMID: 24403084 PMCID: PMC3937658 DOI: 10.1074/jbc.m113.522060] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/27/2013] [Indexed: 11/06/2022] Open
Abstract
The actin-binding protein filamin A (FLNa) regulates neuronal migration during development, yet its roles in the mature brain remain largely obscure. Here, we probed the effects of FLNa on the regulation of ion channels that influence neuronal properties. We focused on the HCN1 channels that conduct Ih, a hyperpolarization-activated current crucial for shaping intrinsic neuronal properties. Whereas regulation of HCN1 channels by FLNa has been observed in melanoma cell lines, its physiological relevance to neuronal function and the underlying cellular pathways that govern this regulation remain unknown. Using a combination of mutational, pharmacological, and imaging approaches, we find here that FLNa facilitates a selective and reversible dynamin-dependent internalization of HCN1 channels in HEK293 cells. This internalization is accompanied by a redistribution of HCN1 channels on the cell surface, by accumulation of the channels in endosomal compartments, and by reduced Ih density. In hippocampal neurons, expression of a truncated dominant-negative FLNa enhances the expression of native HCN1. Furthermore, acute abrogation of HCN1-FLNa interaction in neurons, with the use of decoy peptides that mimic the FLNa-binding domain of HCN1, abolishes the punctate distribution of HCN1 channels in neuronal cell bodies, augments endogenous Ih, and enhances the rebound-response ("voltage-sag") of the neuronal membrane to transient hyperpolarizing events. Together, these results support a major function of FLNa in modulating ion channel abundance and membrane trafficking in neurons, thereby shaping their biophysical properties and function.
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Affiliation(s)
- Yoav Noam
- From the Departments of Anatomy/Neurobiology and Pediatrics and
| | | | - Annie Koh
- From the Departments of Anatomy/Neurobiology and Pediatrics and
| | | | - Erik M. M. Manders
- van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, 1098XH Amsterdam, The Netherlands
| | - Geoffrey W. Abbott
- Pharmacology, University of California at Irvine, Irvine, California 92697-4475 and
| | | | - Tallie Z. Baram
- From the Departments of Anatomy/Neurobiology and Pediatrics and
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28
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Yang Z, Yuan Y, Jiang R, Fu N, Lu X, Tian C, Hu W, Fan Q, Huang W. Homogeneous near-infrared emissive polymeric nanoparticles based on amphiphilic diblock copolymers with perylene diimide and PEG pendants: self-assembly behavior and cellular imaging application. Polym Chem 2014. [DOI: 10.1039/c3py01197f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Liu X, Ye R, Yan T, Yu SP, Wei L, Xu G, Fan X, Jiang Y, Stetler RA, Liu G, Chen J. Cell based therapies for ischemic stroke: from basic science to bedside. Prog Neurobiol 2013; 115:92-115. [PMID: 24333397 DOI: 10.1016/j.pneurobio.2013.11.007] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/11/2013] [Accepted: 11/26/2013] [Indexed: 12/20/2022]
Abstract
Cell therapy is emerging as a viable therapy to restore neurological function after stroke. Many types of stem/progenitor cells from different sources have been explored for their feasibility and efficacy for the treatment of stroke. Transplanted cells not only have the potential to replace the lost circuitry, but also produce growth and trophic factors, or stimulate the release of such factors from host brain cells, thereby enhancing endogenous brain repair processes. Although stem/progenitor cells have shown a promising role in ischemic stroke in experimental studies as well as initial clinical pilot studies, cellular therapy is still at an early stage in humans. Many critical issues need to be addressed including the therapeutic time window, cell type selection, delivery route, and in vivo monitoring of their migration pattern. This review attempts to provide a comprehensive synopsis of preclinical evidence and clinical experience of various donor cell types, their restorative mechanisms, delivery routes, imaging strategies, future prospects and challenges for translating cell therapies as a neurorestorative regimen in clinical applications.
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Affiliation(s)
- Xinfeng Liu
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
| | - Ruidong Ye
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Tao Yan
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA; Department of Neurology, Tianjin General Hospital, Tianjin University School of Medicine, Tianjin, China
| | - Shan Ping Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Ling Wei
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gelin Xu
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xinying Fan
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Yongjun Jiang
- Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - R Anne Stetler
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - George Liu
- Institute of Cardiovascular Sciences, Peking University Health Science Center, Beijing, China
| | - Jieli Chen
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.
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30
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Abstract
This review is focused on a novel cellular probe, the plasmonic nanobubble (PNB), which has the dynamically tunable and multiple functions of imaging, diagnosis, delivery, therapy and, ultimately, theranostics. The concept of theranostics was recently introduced in order to unite the clinically important stages of treatment, namely diagnosis, therapy and therapy guidance, into one single, rapid and highly accurate procedure. Cell level theranostics will have far-reaching implications for the treatment of cancer and other diseases at their earliest stages. PNBs were developed to support cell level theranostics as a new generation of on-demand tunable cellular probes. A PNB is a transient vapor nanobubble that is generated within nanoseconds around an overheated plasmonic nanoparticle with a short laser pulse. In the short term, we expect that PNB technology will be rapidly adaptable to clinical medicine, where the single cell resolution it provides will be critical for diagnosing incipient or residual disease and eliminating cancer cells, while leaving healthy cells intact. This review discusses mechanisms of plasmonic nanobubbles and their biomedical applications with the focus on cancer cell theranostics.
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Affiliation(s)
- Dmitri Lapotko
- Department of Physics & Astronomy, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA; ; Tel.: +1-713-348-3708
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31
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Zhan Q, He S, Qian J, Cheng H, Cai F. Optimization of optical excitation of upconversion nanoparticles for rapid microscopy and deeper tissue imaging with higher quantum yield. Theranostics 2013; 3:306-16. [PMID: 23650478 PMCID: PMC3645057 DOI: 10.7150/thno.6007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 02/27/2013] [Indexed: 12/04/2022] Open
Abstract
Relatively low quantum yield (QY), time-consuming scanning and strong absorption of light in tissue are some of the issues present in the development of upconversion nanoparticles (UCNPs) for biomedical applications. In this paper we systematically optimize several aspects of optical excitation of UCNPs to improve their applicability in bioimaging and biotherapy. A novel multi-photon evanescent wave (EW) excitation modality is proposed for UCNP-based microscopy. The scanning-free, ultrahigh contrast and high spatiotemporal resolution method could simultaneously track a few particles in a large area with a speed of ³⁺up to 350 frames per second. The HeLa cancer cell membrane imaging was successfully performed using NaYF₄: 20% Yb³⁺/2Er³⁺ targeting nanoparticles. Studies with different tissues were made to illustrate the impact of optical property parameters on the deep imaging ability of 920-nm band excitation. In the experiments a semiconductor laser with a 920 nm wavelength was used to excite UCNPs in tissue phantom at five depths. Our experimental and computational results have shown that in UCNP-based diffusion optical imaging with 920-nm laser excitation could lead to larger imaging depth range compared to traditional 974-nm excitation in a wide dynamic range of tissue species. As the QY is power density dependent, a pulsed laser is proposed to improve the QY of UCNPs. This proposal is promising in drastically increasing the imaging depth and efficiency of photodynamic therapy.
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Affiliation(s)
- Qiuqiang Zhan
- 1. ZJU-SCNU Joint Research Center of Photonics, Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), 510006 Guangzhou, P. R. China
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
| | - Sailing He
- 1. ZJU-SCNU Joint Research Center of Photonics, Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), 510006 Guangzhou, P. R. China
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
- 3. Department of Electromagnetic Engineering, Royal Institute of Technology, 10044 Stockholm, Sweden
| | - Jun Qian
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
| | - Hao Cheng
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
| | - Fuhong Cai
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
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32
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Gussin H, Tomlinson ID, Cao D, Qian H, Rosenthal S, Pepperberg DR. Quantum dot conjugates of GABA and muscimol: binding to α1β2γ2 and ρ1 GABA(A) receptors. ACS Chem Neurosci 2013; 4:435-43. [PMID: 23509979 PMCID: PMC3605815 DOI: 10.1021/cn300144v] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 12/05/2012] [Indexed: 12/18/2022] Open
Abstract
GABAA receptors are ligand-gated ion channels that mediate inhibitory synaptic signaling in the CNS. Fluorescent probes with the ability to target these receptors can provide insights into receptor location, distribution and dynamics in live cells, while revealing abnormalities in their distribution and dynamics that could occur in a variety of diseases. We have developed fluorescent probes of GABAA receptors that are composed of a CdSe/ZnS core-shell nanocrystal (quantum dot; qdot) conjugated to pegylated derivatives of the GABA receptor agonists GABA and muscimol (GABA-qdots and muscimol-qdots, respectively). Quantitative fluorescence imaging was used to analyze the binding activity of these conjugates to α1β2γ2 GABAA and ρ1 GABAA receptors expressed in Xenopus oocytes. The selectivity of these conjugates for α1β2γ2 GABAA and ρ1 GABAA receptors was determined by their ability to compete with the antagonists bicuculline and methyl-(1,2,3,6-tetrahydropyridin-4-yl)phosphinic acid (TPMPA). Both GABA- and muscimol-qdots exhibited robust binding to both α1β2γ2 and ρ1 GABAA receptors. At α1β2γ2 receptors, pretreatment with bicuculline reduced conjugate binding by ≥8-fold on average, an extent far exceeding the reduction produced by TPMPA (~30%). Conversely, at ρ1 receptors, pretreatment with TPMPA inhibited binding by ~10-fold, an extent greatly exceeding the change produced by bicuculline (~50% or less). These results indicate specific binding of muscimol-qdots and GABA-qdots to α1β2γ2 GABAA and ρ1 GABAA receptors in a manner that preserves the respective pharmacological sensitivities of these receptors to TPMPA and bicuculline, and encourage the use of qdot-conjugated neurotransmitter analogs as labeling agents at GABAA receptors.
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Affiliation(s)
- Hélène
A. Gussin
- Lions of Illinois Eye Research Institute,
Department of Ophthalmology and Visual Sciences, University
of Illinois at Chicago, Chicago, Illinois 60612, United
States
| | - Ian D. Tomlinson
- Department of Chemistry and Departments of Physics, Chemical & Biomolecular
Engineering, and Pharmacology, Vanderbilt
University, Nashville, Tennessee 37235, United States
| | - Dingcai Cao
- Lions of Illinois Eye Research Institute,
Department of Ophthalmology and Visual Sciences, University
of Illinois at Chicago, Chicago, Illinois 60612, United
States
| | - Haohua Qian
- Lions of Illinois Eye Research Institute,
Department of Ophthalmology and Visual Sciences, University
of Illinois at Chicago, Chicago, Illinois 60612, United
States
- National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892,
United States
| | - Sandra
J. Rosenthal
- Department of Chemistry and Departments of Physics, Chemical & Biomolecular
Engineering, and Pharmacology, Vanderbilt
University, Nashville, Tennessee 37235, United States
| | - David R. Pepperberg
- Lions of Illinois Eye Research Institute,
Department of Ophthalmology and Visual Sciences, University
of Illinois at Chicago, Chicago, Illinois 60612, United
States
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33
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Brissos R, Ramos D, Lima JC, Mihan FY, Borràs M, de Lapuente J, Cort AD, Rodríguez L. Luminescent zinc salophen derivatives: cytotoxicity assessment and action mechanism studies. NEW J CHEM 2013. [DOI: 10.1039/c3nj41125g] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Cheng H, Qin W, Zhu ZF, Qian J, Qin A, Tang BZ, He S. NANOPARTICLES WITH AGGREGATION-INDUCED EMISSION FOR MONITORING LONG TIME CELL MEMBRANE INTERACTIONS. ACTA ACUST UNITED AC 2013. [DOI: 10.2528/pier13040212] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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35
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Manley NC, Steinberg GK. Tracking stem cells for cellular therapy in stroke. Curr Pharm Des 2012; 18:3685-93. [PMID: 22571604 DOI: 10.2174/138161212802002643] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/06/2012] [Indexed: 01/06/2023]
Abstract
Stem cell transplantation has emerged as a promising treatment strategy for stroke. The development of effective ways to monitor transplanted stem cells is essential to understand how stem cell transplantation enhances stroke recovery and ultimately will be an indispensable tool for advancing stem cell therapy to the clinic. In this review, we describe existing methods of tracking transplanted stem cells in vivo, including optical imaging, magnetic resonance imaging (MRI), and positron emission tomography (PET), with emphasis on the benefits and drawbacks of each imaging approach. Key considerations such as the potential impact of each tracking system on stem cell function, as well as its relative applicability to humans are discussed. Finally, we describe multi-modal imaging strategies as a more comprehensive method to track transplanted stem cells in the stroke-injured brain.
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Affiliation(s)
- Nathan C Manley
- Department of Neurosurgery, Stanford Stroke Center and Stanford Institute for Neuro-Innovation and Translational Neurosciences, Stanford University School of Medicine, 300 Pasteur Drive Stanford, California, CA 94305-5327, USA
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36
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Toulme E, Khakh BS. Imaging P2X4 receptor lateral mobility in microglia: regulation by calcium and p38 MAPK. J Biol Chem 2012; 287:14734-48. [PMID: 22393055 DOI: 10.1074/jbc.m111.329334] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
ATP-gated ionotropic P2X4 receptors are up-regulated in activated microglia and are critical for the development of neuropathic pain, a microglia-associated disorder. However, the nature of how plasma membrane P2X4 receptors are regulated in microglia is not fully understood. We used single-molecule imaging to track quantum dot-labeled P2X4 receptors to explore P2X4 receptor mobility in the processes of resting and activated microglia. We find that plasma membrane P2X4 receptor lateral mobility in resting microglial processes is largely random, consisting of mobile and slowly mobile receptors. Moreover, lateral mobility is P2X subunit- and cell-specific, increased in an ATP activation and calcium-dependent manner, and enhanced in activated microglia by the p38 MAPK pathway that selectively regulates slowly mobile receptors. Thus, our data indicate that P2X4 receptors are dynamically regulated mobile ATP sensors, sampling more of the plasma membrane in response to ATP and during the activated state of microglia that is associated with nervous system dysfunction.
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Affiliation(s)
- Estelle Toulme
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, USA
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37
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Hong G, Wu JZ, Robinson JT, Wang H, Zhang B, Dai H. Three-dimensional imaging of single nanotube molecule endocytosis on plasmonic substrates. Nat Commun 2012; 3:700. [DOI: 10.1038/ncomms1698] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 01/23/2012] [Indexed: 11/09/2022] Open
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38
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Neuronal P2X2 receptors are mobile ATP sensors that explore the plasma membrane when activated. J Neurosci 2012; 31:16716-30. [PMID: 22090499 DOI: 10.1523/jneurosci.3362-11.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ATP-gated ionotropic P2X2 receptors are widely expressed in neurons. Although the electrophysiological properties of P2X2 receptors have been extensively studied, little is known about the plasma membrane lateral mobility of P2X2 receptors or whether receptor mobility is regulated by ATP. Here we used single-molecule imaging with simultaneous whole-cell voltage-clamp recordings to track quantum dot-labeled P2X2 receptors in the dendrites of rat hippocampal neurons to explore P2X2 receptor mobility and its regulation. We find that plasma membrane P2X2 receptor lateral mobility in dendrites is heterogeneous but mostly Brownian in nature, consisting of mobile and slowly mobile receptor pools. Moreover, lateral mobility is P2X2 subunit and cell specific, is increased in an activation-dependent manner, and is regulated by cytosolic VILIP1, a calcium binding protein. Our data provide the first direct measures of P2X receptor mobility and show that P2X2 receptors are mobile ATP sensors, sampling more of the dendritic plasma membrane in response to ATP.
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39
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Tomczak N, Jańczewski D, Dorokhin D, Han MY, Vancso GJ. Enabling biomedical research with designer quantum dots. Methods Mol Biol 2012; 811:245-265. [PMID: 22042684 DOI: 10.1007/978-1-61779-388-2_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Quantum Dots (QDs) are a new class of semiconductor nanoparticulate luminophores, which are actively researched for novel applications in biology and nanomedicine. In this review, the recent progress in the design and applications of QD labels for in vitro and in vivo imaging of cells is presented. Surface chemical engineering of hydrophobic QDs is required to render them water soluble and biocompatible. Further surface modification and attachment of bioactive molecules to the surface of QDs, such as peptides, aptamers, or antibodies are intensively explored for targeted imaging of living cells, and disease states in animals. Specially designed surface coatings can drastically decrease nonspecific interactions between QDs and cells, minimize degradation of QDs under in vivo physiological conditions, reduce the cytotoxicity of QDs, and prolong circulation lifetimes in animals. New generations of QD probes are also promising for imaging cellular processes at the single-molecule level. Ultimately, QDs as components of complex therapeutic nanosystems are poised to contribute significantly to the field of personalized medicine.
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Affiliation(s)
- Nikodem Tomczak
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.
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40
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Valentine CD, Verkman AS, Haggie PM. Protein trafficking rates assessed by quantum dot quenching with bromocresol green. Traffic 2011; 13:25-9. [PMID: 21951589 DOI: 10.1111/j.1600-0854.2011.01287.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Quantum dots are bright, photostable fluorophores used extensively to investigate biological processes. In this study, we report that bromocresol green (BCG) at low micromolar concentrations rapidly, efficiently and reversibly quenches the fluorescence of commercial quantum dots having a wide range of functionalities. The broad utility of BCG quenching of quantum dots in cell biology is showed in quantitative assays of trafficking of the β(2) -adrenergic receptor (β(2) AR) and the cystic fibrosis transmembrane conductance regulator (CFTR).
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41
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Suzuki T, Kondo C, Kanamori T, Inouye S. Video-rate bioluminescence imaging of matrix metalloproteinase-2 secreted from a migrating cell. PLoS One 2011; 6:e25243. [PMID: 21969874 PMCID: PMC3182179 DOI: 10.1371/journal.pone.0025243] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 08/29/2011] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Matrix metalloproteinase-2 (MMP-2) plays an important role in cancer progression and metastasis. MMP-2 is secreted as a pro-enzyme, which is activated by the membrane-bound proteins, and the polarized distribution of secretory and the membrane-associated MMP-2 has been investigated. However, the real-time visualizations of both MMP-2 secretion from the front edge of a migration cell and its distribution on the cell surface have not been reported. METHODOLOGY/PRINCIPAL FINDINGS The method of video-rate bioluminescence imaging was applied to visualize exocytosis of MMP-2 from a living cell using Gaussia luciferase (GLase) as a reporter. The luminescence signals of GLase were detected by a high speed electron-multiplying charge-coupled device camera (EM-CCD camera) with a time resolution within 500 ms per image. The fusion protein of MMP-2 to GLase was expressed in a HeLa cell and exocytosis of MMP-2 was detected in a few seconds along the leading edge of a migrating HeLa cell. The membrane-associated MMP-2 was observed at the specific sites on the bottom side of the cells, suggesting that the sites of MMP-2 secretion are different from that of MMP-2 binding. CONCLUSIONS We were the first to successfully demonstrate secretory dynamics of MMP-2 and the specific sites for polarized distribution of MMP-2 on the cell surface. The video-rate bioluminescence imaging using GLase is a useful method to investigate distribution and dynamics of secreted proteins on the whole surface of polarized cells in real time.
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Affiliation(s)
- Takahiro Suzuki
- Department of Biochemistry, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Chihiro Kondo
- Department of Biochemistry, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Takao Kanamori
- Department of Biochemistry, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Satoshi Inouye
- Yokohama Research Center, JNC Corporation, Yokohama, Japan
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Thuenauer R, Juhasz K, Mayr R, Frühwirth T, Lipp AM, Balogi Z, Sonnleitner A. A PDMS-based biochip with integrated sub-micrometre position control for TIRF microscopy of the apical cell membrane. LAB ON A CHIP 2011; 11:3064-71. [PMID: 21814704 DOI: 10.1039/c1lc20458k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A poly(dimethylsiloxane) (PDMS)-based biochip with an integrated pressure controlled positioning system with sub-micrometre precision was realized. The biochip was easy and cheap to manufacture and enabled positioning in a wet environment. It allowed the application of total internal reflection fluorescence (TIRF) microscopy at the dorsal cell membrane, which is not adhering to a support. Specifically, the chip enabled TIRF microscopy at the apical membrane of polarized epithelial cells. Thereby, the device allowed us for the first time to monitor individual fusion events of GPI-GFP bearing vesicles at the apical membrane in live Madin-Darby canine kidney II (MDCK II) cells. Moreover, a mapping of fusion sites became feasible and revealed that the whole apical membrane is fusion competent. In total, the biochip offers an all-in-one solution for apical TIRF microscopy and contributes a novel tool to study trafficking processes close to the apical plasma membrane in polarized epithelial cells.
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Affiliation(s)
- Roland Thuenauer
- Center for Advanced Bioanalysis GmbH, Scharitzerstrasse 6-8, 4020, Linz, Austria.
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43
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Kuo CW, Chueh DY, Singh N, Chien FC, Chen P. Targeted nuclear delivery using peptide-coated quantum dots. Bioconjug Chem 2011; 22:1073-80. [PMID: 21528926 DOI: 10.1021/bc100527m] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Core/shell quantum dots (CdSe/Zns) conjugated with various nuclear localization signaling (NLS) peptides, which could facilitate the transportation of quantum dots across the plasma membrane into the nucleus, have been utilized to investigate the uptake mechanism of targeted delivery. Because of their brightness and photostability, it was possible to trace the trajectories of individual quantum dots in living cells using both confocal and total internal reflection microscopes. We found that, when the quantum dots were added to a cell culture, the peptide-coated quantum dots entered the cell nucleus while the uncoated quantum dots remained in the cytoplasm. At 8 nM, most of the peptide coated quantum dots were found in the cytoplasm due to aggregation. However, at a lower concentration (0.08 nM), approximately 25% of the NLS peptide-coated quantum dots entered the cell nucleus. We also found that some quantum dots without NLS coating could also enter the nucleus, suggesting that the size of the quantum dots may play an important role in such a process.
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Affiliation(s)
- Chiung-Wen Kuo
- Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei 115, Taiwan
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Yang Y, Xu Y, Xia T, Chen F, Zhang C, Liang W, Lai L, Fang X. A single-molecule study of the inhibition effect of Naringenin on transforming growth factor-β ligand-receptor binding. Chem Commun (Camb) 2011; 47:5440-2. [PMID: 21475751 DOI: 10.1039/c1cc10778j] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With single-molecule fluorescence imaging and single-molecule force measurement, we have found that the natural compound Naringenin exerts an inhibition effect on TGF-β ligand-receptor interaction, the initial step of TGF-β signaling.
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Affiliation(s)
- Yong Yang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, PR China
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45
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Abstract
Observing individual molecules in a complex environment by fluorescence microscopy is becoming increasingly important in biological and medical research, for which critical reduction of observation volume is required. Here, we demonstrate the use of vertically aligned silicon dioxide nanopillars to achieve below-the-diffraction-limit observation volume in vitro and inside live cells. With a diameter much smaller than the wavelength of visible light, a transparent silicon dioxide nanopillar embedded in a nontransparent substrate restricts the propagation of light and affords evanescence wave excitation along its vertical surface. This effect creates highly confined illumination volume that selectively excites fluorescence molecules in the vicinity of the nanopillar. We show that this nanopillar illumination can be used for in vitro single-molecule detection at high fluorophore concentrations. In addition, we demonstrate that vertical nanopillars interface tightly with live cells and function as highly localized light sources inside the cell. Furthermore, specific chemical modification of the nanopillar surface makes it possible to locally recruit proteins of interest and simultaneously observe their behavior within the complex, crowded environment of the cell.
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46
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Gussin HA, Tomlinson ID, Muni NJ, Little DM, Qian H, Rosenthal SJ, Pepperberg DR. GABAC receptor binding of quantum-dot conjugates of variable ligand valency. Bioconjug Chem 2011; 21:1455-64. [PMID: 20715850 DOI: 10.1021/bc100050s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Highly fluorescent CdSe quantum dots (qdots) can serve as a platform for tethering multiple copies of a receptor-targeted ligand, affording study of how the level of multivalency affects receptor binding. We previously showed that qdots conjugated with long PEG chains terminated by muscimol, a known GABA(C) agonist, exhibit specific binding to the surface membrane of GABA(C) receptor-expressing Xenopus oocytes. The present report addresses the effect of varying the number, i.e., valency, of muscimol- (M-) terminated PEG chains attached to the qdot on binding of the resulting conjugate to GABA(C) receptors. M-PEG-qdots of differing muscimol valency were prepared by conjugating AMP-CdSe/ZnS qdots with muscimol-terminated and methylamine-terminated PEG chains in proportions designed to yield varying percentages of muscimol-terminated chains among the total approximately 150-200 chains bound to the qdot. The investigated valencies represented 0%, approximately 25%, approximately 50%, and 100% loading with muscimol (preparations termed M-PEG-qdot0, M-PEG-qdot25, M-PEG-qdot50, and M-PEG-qdot100, respectively. Binding of a given conjugate to surface membranes of GABA(C) receptor-expressing oocytes was analyzed by quantitative fluorescence microscopy following defined incubation with approximately 30 nM of the conjugate. With 5-20 min incubation, the fluorescence signal resulting from incubation with M-PEG-qdot25 exceeded, by approximately 6-fold, the fluorescence level obtained with M-PEG-qdot preparations that lacked muscimol-terminated chains (M-PEG-qdot0). M-PEG-qdot50 yielded a net signal roughly similar to that of M-PEG-qdot25, and that produced by M-PEG-qdot100 exceeded, by approximately 30-50%, those for M-PEG-qdot25 and M-PEG-qdot50. The time course of changes in oocyte surface membrane fluorescence resulting from the introduction of and removal of M-PEG-qdots in the medium bathing the oocyte indicated only a modest dependence of both binding and wash-out kinetics on muscimol valency. The results demonstrate a dependence of the binding activity of the M-PEG-qdot conjugates on muscimol valency, presumably reflecting higher GABA(C) avidity and/or affinity of the muscimol at high valency, and provide insight on the interactions of membrane receptor proteins with qdot conjugates containing multiple copies of a receptor-targeting ligand.
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Affiliation(s)
- Hélène A Gussin
- Departments of Ophthalmology and Visual Sciences, Bioengineering, Neurology and Rehabilitation, University of Illinois at Chicago, 1855 W. Taylor St., Chicago, IL 60612, USA
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Barfod ET, Moore AL, Van de Graaf BG, Lidofsky SD. Myosin light chain kinase and Src control membrane dynamics in volume recovery from cell swelling. Mol Biol Cell 2011; 22:634-50. [PMID: 21209319 PMCID: PMC3046060 DOI: 10.1091/mbc.e10-06-0514] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
MLCK resolves membrane blebbing induced by osmotic cell swelling. Cell swelling also stimulates the formation of a Src–MLCK complex, which with cortactin and dynamin forms actin-based structures at the base of the cell to facilitate membrane retrieval for volume recovery. The expansion of the plasma membrane, which occurs during osmotic swelling of epithelia, must be retrieved for volume recovery, but the mechanisms are unknown. Here we have identified myosin light chain kinase (MLCK) as a regulator of membrane internalization in response to osmotic swelling in a model liver cell line. On hypotonic exposure, we found that there was time-dependent phosphorylation of the MLCK substrate myosin II regulatory light chain. At the sides of the cell, MLCK and myosin II localized to swelling-induced membrane blebs with actin just before retraction, and MLCK inhibition led to persistent blebbing and attenuated cell volume recovery. At the base of the cell, MLCK also localized to dynamic actin-coated rings and patches upon swelling, which were associated with uptake of the membrane marker FM4-64X, consistent with sites of membrane internalization. Hypotonic exposure evoked increased biochemical association of the cell volume regulator Src with MLCK and with the endocytosis regulators cortactin and dynamin, which colocalized within these structures. Inhibition of either Src or MLCK led to altered patch and ring lifetimes, consistent with the concept that Src and MLCK form a swelling-induced protein complex that regulates volume recovery through membrane turnover and compensatory endocytosis under osmotic stress.
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Affiliation(s)
- Elisabeth T Barfod
- Department of Pharmacology, University of Vermont, Burlington, VT 05405 Department of Medicine, University of Vermont, Burlington, VT 05405, USA
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Lam AD, Ismail S, Wu R, Yizhar O, Passmore DR, Ernst SA, Stuenkel EL. Mapping dynamic protein interactions to insulin secretory granule behavior with TIRF-FRET. Biophys J 2010; 99:1311-20. [PMID: 20713017 DOI: 10.1016/j.bpj.2010.06.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 05/26/2010] [Accepted: 06/04/2010] [Indexed: 10/19/2022] Open
Abstract
Biological processes are governed by extensive networks of dynamic molecular interactions. Yet, establishing a spatial and temporal map of these interactions and their direct relationship to specific cell functions has remained a challenge. Here, we implement sensitized emission Förster resonance energy transfer (FRET) stoichiometry under total internal reflection fluorescence (TIRF) microscopy. We demonstrate through quantitative analysis and modeling that evanescent fields must be precisely matched between FRET excitation wavelengths to isolate dynamic interactions between bimolecular FRET pairs that are not entirely membrane-delimited. We then use TIRF-FRET to monitor the behavior of individual insulin-containing secretory granules at the plasma membrane of living cells, while simultaneously tracking the dynamic interaction between the GTPase Rab27A and its effector Slp4A, on those same granules. Notably, insulin granules that underwent exocytosis demonstrated a specific increase in Rab27A-GTP/Slp4A FRET in the 5 s before membrane fusion, which coincided temporally with an increase in granule displacement and mobility. These results demonstrate an initial spatiotemporal mapping of a dynamic protein-protein interaction on individual secretory granules that is linked to a specific granule behavior in living cells.
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Affiliation(s)
- Alice D Lam
- Department of Molecular and Integrative Physiology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA
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Cheng W, Klauke N, Smith G, Cooper JM. Microfluidic cell arrays for metabolic monitoring of stimulated cardiomyocytes. Electrophoresis 2010; 31:1405-13. [PMID: 20333720 DOI: 10.1002/elps.200900579] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An array of PDMS microchambers was aligned to an array of sensor electrodes and stimulating microelectrodes, which was used for the electrochemical monitoring of the metabolic activity of single isolated adult ventricular myocytes inside the chamber array, stimulated within a transient electric field. The effect of the accumulation of metabolic byproducts in the limited extracellular volume of the picolitre chambers was demonstrated by measuring single muscle cell contraction optically, while concomitant changes in intracellular calcium transients and pH were recorded independently using fluorescent indicator dyes. Both the amplitude of the cell shortening and the magnitude of the intracellular calcium transients decreased over time and both nearly ceased after 20 min of continuous stimulation in the limited extracellullar volume. The intracellular pH decreased gradually during 20 min of continuous stimulation after which a dramatic pH drop was observed, indicating the breakdown of the intracellular buffering capacity. After continuous stimulation, intracellular lactate was released into the microchamber through cell electroporation and was detected electrochemically at a lactate microbiosensor, within the chamber. A mitochondrial uncoupler was used to mimic ischaemia and thus to enhance the cellular content of lactate. Under these circumstances, intracellular lactate concentrations were found to have risen to approximately 15 mM. This array system has the potential of simultaneous electrochemical and optical monitoring of extracellular and intracellular metabolites from single beating heart cells at a controlled metabolic state.
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Affiliation(s)
- Wei Cheng
- Department of Electronics, University of Glasgow, UK
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50
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Bioanalytical tools for single-cell study of exocytosis. Anal Bioanal Chem 2010; 397:3281-304. [PMID: 20521141 DOI: 10.1007/s00216-010-3843-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 05/08/2010] [Accepted: 05/11/2010] [Indexed: 10/19/2022]
Abstract
Regulated exocytosis is a fundamental biological process used to deliver chemical messengers for cell-cell communication via membrane fusion and content secretion. A plethora of cell types employ this chemical-based communication to achieve crucial functions in many biological systems. Neurons in the brain and platelets in the circulatory system are representative examples utilizing exocytosis for neurotransmission and blood clotting. Single-cell studies of regulated exocytosis in the past several decades have greatly expanded our knowledge of this critical process, from vesicle/granule transport and docking at the early stages of exocytosis to membrane fusion and to eventual chemical messenger secretion. Herein, four main approaches that have been widely used to study single-cell exocytosis will be highlighted, including total internal reflection fluorescence microscopy, capillary electrophoresis, single-cell mass spectrometry, and microelectrochemistry. These techniques are arranged in the order following the route of a vesicle/granule destined for secretion. Within each section, the basic principles and experimental strategies are reviewed and representative examples are given revealing critical spatial, temporal, and chemical information of a secretory vesicle/granule at different stages of its lifetime. Lastly, an analytical chemist's perspective on potential future developments in this exciting field is discussed.
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