1
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Wang D, Woodcock E, Yang X, Nishikawa H, Sviderskaya EV, Oshima M, Edwards C, Zhang Y, Korchev Y. Exploration of individual colorectal cancer cell responses to H 2O 2 eustress using hopping probe scanning ion conductance microscopy. Sci Bull (Beijing) 2024:S2095-9273(24)00222-6. [PMID: 38644130 DOI: 10.1016/j.scib.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/12/2024] [Accepted: 03/25/2024] [Indexed: 04/23/2024]
Abstract
Colorectal cancer (CRC), a widespread malignancy, is closely associated with tumor microenvironmental hydrogen peroxide (H2O2) levels. Some clinical trials targeting H2O2 for cancer treatment have revealed its paradoxical role as a promoter of cancer progression. Investigating the dynamics of cancer cell H2O2 eustress at the single-cell level is crucial. In this study, non-contact hopping probe mode scanning ion conductance microscopy (HPICM) with high-sensitive Pt-functionalized nanoelectrodes was employed to measure dynamic extracellular to intracellular H2O2 gradients in individual colorectal cancer Caco-2 cells. We explored the relationship between cellular mechanical properties and H2O2 gradients. Exposure to 0.1 or 1 mmol/L H2O2 eustress increased the extracellular to intracellular H2O2 gradient from 0.3 to 1.91 or 3.04, respectively. Notably, cellular F-actin-dependent stiffness increased at 0.1 mmol/L but decreased at 1 mmol/L H2O2 eustress. This H2O2-induced stiffness modulated AKT activation positively and glutathione peroxidase 2 (GPX2) expression negatively. Our findings unveil the failure of some H2O2-targeted therapies due to their ineffectiveness in generating H2O2, which instead acts eustress to promote cancer cell survival. This research also reveals the complex interplay between physical properties and biochemical signaling in cancer cells' antioxidant defense, illuminating the exploitation of H2O2 eustress for survival at the single-cell level. Inhibiting GPX and/or catalase (CAT) enhances the cytotoxic activity of H2O2 eustress against CRC cells, which holds significant promise for developing innovative therapies targeting cancer and other H2O2-related inflammatory diseases.
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Affiliation(s)
- Dong Wang
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Emily Woodcock
- Department of Medicine, Imperial College London, London W12 0NN, United Kingdom; Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, United Kingdom
| | - Xi Yang
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Hiromi Nishikawa
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Elena V Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, United Kingdom
| | - Masanobu Oshima
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Christopher Edwards
- Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Yanjun Zhang
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan; Department of Medicine, Imperial College London, London W12 0NN, United Kingdom.
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London W12 0NN, United Kingdom; WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan.
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2
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Cai S, Ren R, He J, Wang X, Zhang Z, Luo Z, Tan W, Korchev Y, Edel JB, Ivanov AP. Selective Single-Molecule Nanopore Detection of mpox A29 Protein Directly in Biofluids. Nano Lett 2023; 23:11438-11446. [PMID: 38051760 PMCID: PMC10755749 DOI: 10.1021/acs.nanolett.3c02709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023]
Abstract
Single-molecule antigen detection using nanopores offers a promising alternative for accurate virus testing to contain their transmission. However, the selective and efficient identification of small viral proteins directly in human biofluids remains a challenge. Here, we report a nanopore sensing strategy based on a customized DNA molecular probe that combines an aptamer and an antibody to enhance the single-molecule detection of mpox virus (MPXV) A29 protein, a small protein with an M.W. of ca. 14 kDa. The formation of the aptamer-target-antibody sandwich structures enables efficient identification of targets when translocating through the nanopore. This technique can accurately detect A29 protein with a limit of detection of ∼11 fM and can distinguish the MPXV A29 from vaccinia virus A27 protein (a difference of only four amino acids) and Varicella Zoster Virus (VZV) protein directly in biofluids. The simplicity, high selectivity, and sensitivity of this approach have the potential to contribute to the diagnosis of viruses in point-of-care settings.
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Affiliation(s)
- Shenglin Cai
- Department
of Chemistry, Imperial College London, Molecular
Science Research Hub, White City Campus, 82 Wood Lane, London W12
0BZ, U.K.
| | - Ren Ren
- Department
of Chemistry, Imperial College London, Molecular
Science Research Hub, White City Campus, 82 Wood Lane, London W12
0BZ, U.K.
- Department
of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith
Campus, Du Cane Road, London W12 0NN, U.K.
- Nano
Life Science Institute (WPI-NanoLSI), Kanazawa
University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Jiaxuan He
- The
Key Laboratory of Zhejiang Province for Aptamers and Theranostics,
Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, People’s
Republic of China
| | - Xiaoyi Wang
- Department
of Chemistry, Imperial College London, Molecular
Science Research Hub, White City Campus, 82 Wood Lane, London W12
0BZ, U.K.
| | - Zheng Zhang
- The
Key Laboratory of Zhejiang Province for Aptamers and Theranostics,
Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, People’s
Republic of China
| | - Zhaofeng Luo
- The
Key Laboratory of Zhejiang Province for Aptamers and Theranostics,
Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, People’s
Republic of China
| | - Weihong Tan
- The
Key Laboratory of Zhejiang Province for Aptamers and Theranostics,
Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, People’s
Republic of China
| | - Yuri Korchev
- Department
of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith
Campus, Du Cane Road, London W12 0NN, U.K.
- Nano
Life Science Institute (WPI-NanoLSI), Kanazawa
University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Joshua B. Edel
- Department
of Chemistry, Imperial College London, Molecular
Science Research Hub, White City Campus, 82 Wood Lane, London W12
0BZ, U.K.
| | - Aleksandar P. Ivanov
- Department
of Chemistry, Imperial College London, Molecular
Science Research Hub, White City Campus, 82 Wood Lane, London W12
0BZ, U.K.
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3
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Ren R, Cai S, Fang X, Wang X, Zhang Z, Damiani M, Hudlerova C, Rosa A, Hope J, Cook NJ, Gorelkin P, Erofeev A, Novak P, Badhan A, Crone M, Freemont P, Taylor GP, Tang L, Edwards C, Shevchuk A, Cherepanov P, Luo Z, Tan W, Korchev Y, Ivanov AP, Edel JB. Multiplexed detection of viral antigen and RNA using nanopore sensing and encoded molecular probes. Nat Commun 2023; 14:7362. [PMID: 37963924 PMCID: PMC10646045 DOI: 10.1038/s41467-023-43004-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 10/27/2023] [Indexed: 11/16/2023] Open
Abstract
We report on single-molecule nanopore sensing combined with position-encoded DNA molecular probes, with chemistry tuned to simultaneously identify various antigen proteins and multiple RNA gene fragments of SARS-CoV-2 with high sensitivity and selectivity. We show that this sensing strategy can directly detect spike (S) and nucleocapsid (N) proteins in unprocessed human saliva. Moreover, our approach enables the identification of RNA fragments from patient samples using nasal/throat swabs, enabling the identification of critical mutations such as D614G, G446S, or Y144del among viral variants. In particular, it can detect and discriminate between SARS-CoV-2 lineages of wild-type B.1.1.7 (Alpha), B.1.617.2 (Delta), and B.1.1.539 (Omicron) within a single measurement without the need for nucleic acid sequencing. The sensing strategy of the molecular probes is easily adaptable to other viral targets and diseases and can be expanded depending on the application required.
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Affiliation(s)
- Ren Ren
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Shenglin Cai
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Xiaona Fang
- The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, 310022, Hangzhou, Zhejiang, China
| | - Xiaoyi Wang
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK
| | - Zheng Zhang
- The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, 310022, Hangzhou, Zhejiang, China
| | - Micol Damiani
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK
| | - Charlotte Hudlerova
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK
| | - Annachiara Rosa
- The Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, London, UK
- Wolfson Education Centre, Faculty of Medicine, Imperial College London, London, UK
| | - Joshua Hope
- The Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, London, UK
| | - Nicola J Cook
- The Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, London, UK
| | - Peter Gorelkin
- National University of Science and Technology "MISIS", Leninskiy Prospect 4, 119991, Moscow, Russian Federation
| | - Alexander Erofeev
- National University of Science and Technology "MISIS", Leninskiy Prospect 4, 119991, Moscow, Russian Federation
| | - Pavel Novak
- ICAPPIC Limited, The Fisheries, Mentmore Terrace, London, E8 3PN, UK
| | - Anjna Badhan
- Molecular Diagnostic Unit, Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Michael Crone
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Paul Freemont
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Graham P Taylor
- Molecular Diagnostic Unit, Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Longhua Tang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 310027, Hangzhou, China
| | - Christopher Edwards
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
- ICAPPIC Limited, The Fisheries, Mentmore Terrace, London, E8 3PN, UK
| | - Andrew Shevchuk
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Peter Cherepanov
- The Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, London, UK
- Molecular Diagnostic Unit, Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Zhaofeng Luo
- The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, 310022, Hangzhou, Zhejiang, China
| | - Weihong Tan
- The Key Laboratory of Zhejiang Province for Aptamers and Theranostics, Aptamer Selection Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, 310022, Hangzhou, Zhejiang, China.
| | - Yuri Korchev
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Aleksandar P Ivanov
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK.
| | - Joshua B Edel
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, 82 Wood Lane, London, W12 0BZ, UK.
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4
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Kolmogorov V, Erofeev A, Vaneev A, Gorbacheva L, Kolesov D, Klyachko N, Korchev Y, Gorelkin P. Scanning Ion-Conductance Microscopy for Studying Mechanical Properties of Neuronal Cells during Local Delivery of Glutamate. Cells 2023; 12:2428. [PMID: 37887273 PMCID: PMC10604991 DOI: 10.3390/cells12202428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/06/2023] [Accepted: 10/08/2023] [Indexed: 10/28/2023] Open
Abstract
Mechanical properties of neuronal cells have a key role for growth, generation of traction forces, adhesion, migration, etc. Mechanical properties are regulated by chemical signaling, neurotransmitters, and neuronal ion exchange. Disturbance of chemical signaling is accompanied by several diseases such as ischemia, trauma, and neurodegenerative diseases. It is known that the disturbance of chemical signaling, like that caused by glutamate excitotoxicity, leads to the structural reorganization of the cytoskeleton of neuronal cells and the deviation of native mechanical properties. Thus, to investigate the mechanical properties of living neuronal cells in the presence of glutamate, it is crucial to use noncontact and low-stress methods, which are the advantages of scanning ion-conductance microscopy (SICM). Moreover, a nanopipette may be used for the local delivery of small molecules as well as for a probe. In this work, SICM was used as an advanced technique for the simultaneous local delivery of glutamate and investigation of living neuronal cell morphology and mechanical behavior caused by an excitotoxic effect of glutamate.
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Affiliation(s)
- Vasilii Kolmogorov
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS”, Moscow 119049, Russia
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Alexander Erofeev
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS”, Moscow 119049, Russia
| | - Alexander Vaneev
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS”, Moscow 119049, Russia
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Lyubov Gorbacheva
- Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
- Faculty of Biomedicine, Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | - Dmitry Kolesov
- Research Laboratory of SPM, Moscow Polytechnic University, Moscow 107023, Russia
| | - Natalia Klyachko
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London SW7 2BX, UK
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Petr Gorelkin
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS”, Moscow 119049, Russia
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5
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Woodcock E, Gorelkin PV, Goff PS, Edwards CRW, Zhang Y, Korchev Y, Sviderskaya EV. Measuring Melanoma Nanomechanical Properties in Relation to Metastatic Ability and Anti-Cancer Drug Treatment Using Scanning Ion Conductance Microscopy. Cells 2023; 12:2401. [PMID: 37830615 PMCID: PMC10571876 DOI: 10.3390/cells12192401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
A cell's mechanical properties have been linked to cancer development, motility and metastasis and are therefore an attractive target as a universal, reliable cancer marker. For example, it has been widely published that cancer cells show a lower Young's modulus than their non-cancerous counterparts. Furthermore, the effect of anti-cancer drugs on cellular mechanics may offer a new insight into secondary mechanisms of action and drug efficiency. Scanning ion conductance microscopy (SICM) offers a nanoscale resolution, non-contact method of nanomechanical data acquisition. In this study, we used SICM to measure the nanomechanical properties of melanoma cell lines from different stages with increasing metastatic ability. Young's modulus changes following treatment with the anti-cancer drugs paclitaxel, cisplatin and dacarbazine were also measured, offering a novel perspective through the use of continuous scan mode SICM. We found that Young's modulus was inversely correlated to metastatic ability in melanoma cell lines from radial growth, vertical growth and metastatic phases. However, Young's modulus was found to be highly variable between cells and cell lines. For example, the highly metastatic cell line A375M was found to have a significantly higher Young's modulus, and this was attributed to a higher level of F-actin. Furthermore, our data following nanomechanical changes after 24 hour anti-cancer drug treatment showed that paclitaxel and cisplatin treatment significantly increased Young's modulus, attributed to an increase in microtubules. Treatment with dacarbazine saw a decrease in Young's modulus with a significantly lower F-actin corrected total cell fluorescence. Our data offer a new perspective on nanomechanical changes following drug treatment, which may be an overlooked effect. This work also highlights variations in cell nanomechanical properties between previous studies, cancer cell lines and cancer types and questions the usefulness of using nanomechanics as a diagnostic or prognostic tool.
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Affiliation(s)
- Emily Woodcock
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK; (E.W.)
- Department of Medicine, Imperial College London, W12 0NN London, UK (Y.K.)
| | - Peter V. Gorelkin
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Philip S. Goff
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK; (E.W.)
| | | | - Yanjun Zhang
- Department of Medicine, Imperial College London, W12 0NN London, UK (Y.K.)
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yuri Korchev
- Department of Medicine, Imperial College London, W12 0NN London, UK (Y.K.)
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Elena V. Sviderskaya
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK; (E.W.)
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6
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Takahashi Y, Sasaki Y, Yoshida T, Honda K, Zhou Y, Miyamoto T, Motoo T, Higashi H, Shevchuk A, Korchev Y, Ida H, Hanayama R, Fukuma T. Nanopipette Fabrication Guidelines for SICM Nanoscale Imaging. Anal Chem 2023; 95:12664-12672. [PMID: 37599426 DOI: 10.1021/acs.analchem.3c01010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Scanning ion conductance microscopy (SICM) is a promising tool for visualizing the dynamics of nanoscale cell surface topography. However, there are still no guidelines for fabricating nanopipettes with ideal shape consisting of small apertures and thin glass walls. Therefore, most of the SICM imaging has been at a standstill at the submicron scale. In this study, we established a simple and highly reproducible method for the fabrication of nanopipettes with sub-20 nm apertures. To validate the improvement in the spatial resolution, we performed time-lapse imaging of the formation and disappearance of endocytic pits as a model of nanoscale time-lapse topographic imaging. We have also successfully imaged the localization of the hot spot and the released extracellular vesicles. The nanopipette fabrication guidelines for the SICM nanoscale topographic imaging can be an essential tool for understanding cell-cell communication.
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Affiliation(s)
- Yasufumi Takahashi
- Department of Electronics, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Yuya Sasaki
- Division of Electrical Engineering and Computer Science, Kanazawa University, Kanazawa 920-1192, Japan
| | - Takeshi Yoshida
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Kota Honda
- Department of Electronics, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Yuanshu Zhou
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Takafumi Miyamoto
- Division of Electrical Engineering and Computer Science, Kanazawa University, Kanazawa 920-1192, Japan
| | - Tomoko Motoo
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Hiroki Higashi
- Division of Electrical Engineering and Computer Science, Kanazawa University, Kanazawa 920-1192, Japan
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, London W12 0NN, U.K
| | - Yuri Korchev
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
- Department of Medicine, Imperial College London, London W12 0NN, U.K
| | - Hiroki Ida
- Department of Electronics, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Rikinari Hanayama
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Takeshi Fukuma
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
- Division of Electrical Engineering and Computer Science, Kanazawa University, Kanazawa 920-1192, Japan
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7
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Savin N, Erofeev A, Timoshenko R, Vaneev A, Garanina A, Salikhov S, Grammatikova N, Levshin I, Korchev Y, Gorelkin P. Investigation of the Antifungal and Anticancer Effects of the Novel Synthesized Thiazolidinedione by Ion-Conductance Microscopy. Cells 2023; 12:1666. [PMID: 37371136 DOI: 10.3390/cells12121666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/31/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
In connection with the emergence of new pathogenic strains of Candida, the search for more effective antifungal drugs becomes a challenge. Part of the preclinical trials of such drugs can be carried out using the innovative ion-conductance microscopy (ICM) method, whose unique characteristics make it possible to study the biophysical characteristics of biological objects with high accuracy and low invasiveness. We conducted a study of a novel synthesized thiazolidinedione's antimicrobial (for Candida spp.) and anticancer properties (on samples of the human prostate cell line PC3), and its drug toxicity (on a sample of the human kidney cell line HEK293). We used a scanning ion-conductance microscope (SICM) to obtain the topography and mechanical properties of cells and an amperometric method using Pt-nanoelectrodes to register reactive oxygen species (ROS) expression. All data and results are obtained and presented for the first time.
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Affiliation(s)
- Nikita Savin
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Alexander Erofeev
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Roman Timoshenko
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Alexander Vaneev
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Anastasiia Garanina
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Sergey Salikhov
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | | | - Igor Levshin
- G. F. Gauze Research Institute for New Antibiotics, Moscow 119021, Russia
| | - Yuri Korchev
- Faculty of Medicine, Imperial College London, London SW7 2DD, UK
| | - Petr Gorelkin
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
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8
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Takahashi Y, Takamatsu D, Korchev Y, Fukuma T. Correlative Analysis of Ion-Concentration Profile and Surface Nanoscale Topography Changes Using Operando Scanning Ion Conductance Microscopy. JACS Au 2023; 3:1089-1099. [PMID: 37124299 PMCID: PMC10131198 DOI: 10.1021/jacsau.2c00677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 05/03/2023]
Abstract
Although various spectroscopic methods have been developed to capture ion-concentration profile changes, it is still difficult to visualize the ion-concentration profile and surface topographical changes simultaneously during the charging/discharging of lithium-ion batteries (LIBs). To tackle this issue, we have developed an operando scanning ion conductance microscopy (SICM) method that can directly visualize an ion-concentration profile and surface topography using a SICM nanopipette while controlling the sample potential or current with a potentiostat for characterizing the polarization state during charging/discharging. Using operando SICM on the negative electrode (anode) of LIBs, we have characterized ion-concentration profile changes and the reversible volume changes related to the phase transition during cyclic voltammetry (CV) and charge/discharge of the graphite anode. Operando SICM is a versatile technique that is likely to be of major value for evaluating the correlation between the electrolyte concentration profile and nanoscale surface topography changes.
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Affiliation(s)
- Yasufumi Takahashi
- Department
of Electronics, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
- WPI
Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Daiko Takamatsu
- Center
for Exploratory Research, Research &
Development Group, Hitachi, Ltd., Hatoyama-machi, Saitama 350-0395, Japan
| | - Yuri Korchev
- WPI
Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
- Department
of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Takeshi Fukuma
- WPI
Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa 920-1192, Japan
- Division
of Electrical Engineering and Computer Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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9
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Savin N, Erofeev A, Kolmogorov V, Salikhov S, Efremov Y, Timashev P, Grammatikova N, Levshin I, Edwards C, Korchev Y, Gorelkin P. Scanning ion-conductance microscopy technique for studying the topography and mechanical properties of Candida parapsilosis yeast microorganisms. Biomater Sci 2023; 11:611-617. [PMID: 36477151 DOI: 10.1039/d2bm00964a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Super-resolution microscopy is widely used in the development of novel antimicrobial testing in vitro. In the presented work, a scanning protocol was developed by the method of scanning ion-conducting microscopy (SICM), which makes it possible to study microorganisms without rigid fixation and in saline, obtaining an index map of nanosized structures. The effect of azole and echinocandins drugs on the morphology and mechanical properties of Candida parapsilosis yeast was studied. The findings are consistent with previously proposed drug mechanisms and reports that have examined antifungal agents using AFM, SEM, and TEM. We have shown that the SICM method is capable of scanning and detecting the nanomechanical properties of yeast non-invasively.
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Affiliation(s)
| | - Alexander Erofeev
- NUST MISiS, Moscow, Russian Federation. .,Lomonosov Moscow State University, Moscow, Russian Federation
| | - Vasilii Kolmogorov
- NUST MISiS, Moscow, Russian Federation. .,Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - Yuri Efremov
- Institute for Regenerative Medicine I. M. Sechenov, Moscow, Russian Federation
| | - Peter Timashev
- Institute for Regenerative Medicine I. M. Sechenov, Moscow, Russian Federation.,World-class Research Center "Digital Biodesign and Personalized Healthcare", Moscow, Russian Federation.,Chemistry department Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - Igor Levshin
- G. F. Gauze Research Institute for New Antibiotics, Moscow, Russian Federation
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10
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Liu F, Gledhill M, Tan QG, Zhu K, Zhang Q, Salaün P, Tagliabue A, Zhang Y, Weiss D, Achterberg EP, Korchev Y. Phycosphere pH of unicellular nano- and micro- phytoplankton cells and consequences for iron speciation. ISME J 2022; 16:2329-2336. [PMID: 35798938 PMCID: PMC9478132 DOI: 10.1038/s41396-022-01280-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 06/15/2022] [Accepted: 06/22/2022] [Indexed: 11/15/2022]
Abstract
Surface ocean pH is declining due to anthropogenic atmospheric CO2 uptake with a global decline of ~0.3 possible by 2100. Extracellular pH influences a range of biological processes, including nutrient uptake, calcification and silicification. However, there are poor constraints on how pH levels in the extracellular microenvironment surrounding phytoplankton cells (the phycosphere) differ from bulk seawater. This adds uncertainty to biological impacts of environmental change. Furthermore, previous modelling work suggests that phycosphere pH of small cells is close to bulk seawater, and this has not been experimentally verified. Here we observe under 140 μmol photons·m−2·s−1 the phycosphere pH of Chlamydomonas concordia (5 µm diameter), Emiliania huxleyi (5 µm), Coscinodiscus radiatus (50 µm) and C. wailesii (100 µm) are 0.11 ± 0.07, 0.20 ± 0.09, 0.41 ± 0.04 and 0.15 ± 0.20 (mean ± SD) higher than bulk seawater (pH 8.00), respectively. Thickness of the pH boundary layer of C. wailesii increases from 18 ± 4 to 122 ± 17 µm when bulk seawater pH decreases from 8.00 to 7.78. Phycosphere pH is regulated by photosynthesis and extracellular enzymatic transformation of bicarbonate, as well as being influenced by light intensity and seawater pH and buffering capacity. The pH change alters Fe speciation in the phycosphere, and hence Fe availability to phytoplankton is likely better predicted by the phycosphere, rather than bulk seawater. Overall, the precise quantification of chemical conditions in the phycosphere is crucial for assessing the sensitivity of marine phytoplankton to ongoing ocean acidification and Fe limitation in surface oceans.
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11
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Abstract
The reduction in ion current as a fine pipette approaches a cell surface allows the cell surface topography to be imaged, with nanoscale resolution, without contact with the delicate cell surface. A variety of different methods have been developed and refined to scan the topography of the dynamic cell surface at high resolution and speed. Measurement of cell topography can be complemented by performing local probing or mapping of the cell surface using the same pipette. This can be done by performing single-channel recording, applying force, delivering agonists, using pipettes fabricated to contain an electrochemical probe, or combining with fluorescence imaging. These methods in combination have great potential to image and map the surface of live cells at the nanoscale.
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Affiliation(s)
- David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom;
| | - Yuri Korchev
- Imperial College Faculty of Medicine, London Centre for Nanotechnology, London W12 0NN, United Kingdom
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Pavel Novak
- Imperial College Faculty of Medicine, London Centre for Nanotechnology, London W12 0NN, United Kingdom
- National University of Science and Technology (MISiS), Moscow 119991, Russia
| | - Andrew Shevchuk
- Imperial College Faculty of Medicine, London Centre for Nanotechnology, London W12 0NN, United Kingdom
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12
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Sato K, Sato F, Kumano M, Kamijo T, Sato T, Zhou Y, Korchev Y, Fukuma T, Fujimura T, Takahashi Y. Electrochemical Quantitative Evaluation of the Surface Charge of a Poly(1‐Vinylimidazole) Multilayer Film and Application to Nanopore pH Sensor. ELECTROANAL 2021. [DOI: 10.1002/elan.202100041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Katsuhiko Sato
- Faculty of Pharmaceutical Science Tohoku Medical and Pharmaceutical University 4-4-1 Komatsushima, Aoba Sendai Miyagi 981-8558 Japan
- Department of Creative Engineering National Institute of Technology Tsuruoka College 104 Sawada, Inooka Tsuruoka Yamagata 997-8511 Japan
| | - Fumiya Sato
- Graduate School of Pharmaceutical Sciences Tohoku University 6-3 Aoba, Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Masayuki Kumano
- Graduate School of Pharmaceutical Sciences Tohoku University 6-3 Aoba, Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Toshio Kamijo
- Department of Creative Engineering National Institute of Technology Tsuruoka College 104 Sawada, Inooka Tsuruoka Yamagata 997-8511 Japan
| | - Takaya Sato
- Department of Creative Engineering National Institute of Technology Tsuruoka College 104 Sawada, Inooka Tsuruoka Yamagata 997-8511 Japan
| | - Yuanshu Zhou
- Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi Kanazawa 920-1192 Japan
| | - Yuri Korchev
- Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi Kanazawa 920-1192 Japan
- Imperial College London Department of Medicine W12 0NN London United Kingdom
| | - Takeshi Fukuma
- Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi Kanazawa 920-1192 Japan
| | - Tsutomu Fujimura
- Faculty of Pharmaceutical Science Tohoku Medical and Pharmaceutical University 4-4-1 Komatsushima, Aoba Sendai Miyagi 981-8558 Japan
| | - Yasufumi Takahashi
- Nano Life Science Institute (WPI-NanoLSI) Kanazawa University, Kakuma-machi Kanazawa 920-1192 Japan
- Precursory Research for Embryonic Science and Technology (PRESTO) Japan Science and Technology Agency (JST) Saitama 332-0012 Japan
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13
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Abstract
This paper suggests that ATP release induced by the SARS-CoV-2 virus plays a key role in the genesis of the major symptoms and complications of COVID-19. Infection of specific cells which contain the Angiotensin-Converting Enzyme 2 (ACE2) receptor results in a loss of protection of the Mineralocorticoid Receptor (MR). Local activation by cortisol stimulates the release of ATP initially into the basolateral compartment and then by lysosomal exocytosis from the cell surface. This then acts on adjacent cells. In the nose ATP acts as a nociceptive stimulus which results in anosmia. It is suggested that a similar paracrine mechanism is responsible for the loss of taste. In the lung ATP release from type 2 alveolar cells produces the non-productive cough by acting on purinergic receptors on adjacent neuroepithelial cells and activating, via the vagus, the cough reflex. Infection of endothelial cells results in the exocytosis of WeibelPalade bodies. These contain the Von Willebrand Factor responsible for micro-clotting and angiopoietin-2 which increases vascular permeability and plays a key role in the Acute Respiratory Distress Syndrome. To test this hypothesis this paper reports proof of concept studies in which MR blockade using spironolactone and low dose dexamethasone (SpiDex) was given to PCR-confirmed COVID-19 patients. In 80 patients with moderate to severe respiratory failure 40 were given SpiDex and 40 conventional treatment with high dose dexamethasone (HiDex). There was 1 death in the HiDex group and none in the SpiDex. As judged by clinical, biochemical and radiological parameters there were clear statistically significant benefits of SpiDex in comparison to HiDex. A further 20 outpatients with COVID-19 were given SpiDex. There was no control group and the aim was to demonstrate safety. No adverse effects were noted and no patient became hyperkalaemic. 90% were asymptomatic at 10 days. The very positive results suggest that blockade of the MR can produce major benefit in COVID19 patients. Further larger controlled studies of inpatients and outpatients are required not only for SARS-CoV-2 infection per se but also to determine if this treatment affects the incidence of Long COVID.
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Affiliation(s)
- Christopher Edwards
- Hammersmith Hospital, Imperial College, London, United Kingdom
- *Correspondence: Christopher Edwards, ; orcid.org/0000-0003-1025-2095
| | - Oleksandra Klekot
- Clinical Pharmacology Department, Vinnytsia National Pirogov Memorial Medical University, Vinnytsia, Ukraine
| | - Larisa Halugan
- Infection Department, Vinnytsia State Clinical Hospital #3, Vinnytsia, Ukraine
| | - Yuri Korchev
- Hammersmith Hospital, Imperial College, London, United Kingdom
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14
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Bednarska J, Novak P, Korchev Y, Rorsman P, Tarasov AI, Shevchuk A. Release of insulin granules by simultaneous, high-speed correlative SICM-FCM. J Microsc 2020; 282:21-29. [PMID: 33089519 DOI: 10.1111/jmi.12972] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/19/2020] [Indexed: 11/27/2022]
Abstract
Exocytosis of peptides and steroids stored in a dense core vesicular (DCV) form is the final step of every secretory pathway, indispensable for the function of nervous, endocrine and immune systems. The lack of live imaging techniques capable of direct, label-free visualisation of DCV release makes many aspects of the exocytotic process inaccessible to investigation. We describe the application of correlative scanning ion conductance and fluorescence confocal microscopy (SICM-FCM) to study the exocytosis of individual granules of insulin from the top, nonadherent, surface of pancreatic β-cells. Using SICM-FCM, we were first to directly follow the topographical changes associated with physiologically induced release of insulin DCVs. This allowed us to report the kinetics of the full fusion of the insulin vesicle as well as the subsequent solubilisation of the released insulin crystal.
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Affiliation(s)
- J Bednarska
- Department of Medicine, Imperial College London, London, U.K
| | - P Novak
- Department of Medicine, Imperial College London, London, U.K.,National University of Science and Technology 'MISIS', Moscow, Russian Federation
| | - Y Korchev
- Department of Medicine, Imperial College London, London, U.K.,Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - P Rorsman
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Oxford, U.K
| | - A I Tarasov
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Oxford, U.K.,School of Biomedical Sciences, Ulster University, Coleraine, U.K
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, London, U.K
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15
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Bednarska J, Pelchen-Matthews A, Novak P, Burden JJ, Summers PA, Kuimova MK, Korchev Y, Marsh M, Shevchuk A. Rapid formation of human immunodeficiency virus-like particles. Proc Natl Acad Sci U S A 2020; 117:21637-21646. [PMID: 32817566 PMCID: PMC7474690 DOI: 10.1073/pnas.2008156117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Understanding the molecular mechanisms involved in the assembly of viruses is essential for discerning how viruses transmit from cell to cell and host to host. Although molecular aspects of assembly have been studied for many viruses, we still have little information about these events in real time. Enveloped viruses such as HIV that assemble at, and bud from, the plasma membrane have been studied in some detail using live cell fluorescence imaging techniques; however, these approaches provide little information about the real-time morphological changes that take place as viral components come together to form individual virus particles. Here we used correlative scanning ion conductance microscopy and fluorescence confocal microscopy to measure the topological changes, together with the recruitment of fluorescently labeled viral proteins such as Gag and Vpr, during the assembly and release of individual HIV virus-like particles (VLPs) from the top, nonadherent surfaces of living cells. We show that 1) labeling of viral proteins with green fluorescent protein affects particle formation, 2) the kinetics of particle assembly on different plasma membrane domains can vary, possibly as a consequence of differences in membrane biophysical properties, and 3) VLPs budding from the top, unimpeded surface of cells can reach full size in 20 s and disappear from the budding site in 0.5 to 3 min from the moment curvature is initially detected, significantly faster than has been previously reported.
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Affiliation(s)
- Joanna Bednarska
- Department of Medicine, Imperial College London, W12 0NN London, United Kingdom
| | - Annegret Pelchen-Matthews
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, WC1E 6BT London, United Kingdom
| | - Pavel Novak
- Department of Medicine, Imperial College London, W12 0NN London, United Kingdom
- Functional Low-Dimensional Structures Laboratory, National University of Science and Technology "MISIS", 119991 Moscow, Russian Federation
| | - Jemima J Burden
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, WC1E 6BT London, United Kingdom
| | - Peter A Summers
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, W12 0BZ London, United Kingdom
| | - Marina K Kuimova
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, W12 0BZ London, United Kingdom
| | - Yuri Korchev
- Department of Medicine, Imperial College London, W12 0NN London, United Kingdom
- Nano Life Science Institute, Kanazawa University, 920-1192 Kanazawa, Japan
| | - Mark Marsh
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, WC1E 6BT London, United Kingdom;
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, W12 0NN London, United Kingdom;
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16
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Swiatlowska P, Sanchez-Alonso JL, Mansfield C, Scaini D, Korchev Y, Novak P, Gorelik J. Short-term angiotensin II treatment regulates cardiac nanomechanics via microtubule modifications. Nanoscale 2020; 12:16315-16329. [PMID: 32720664 DOI: 10.1039/d0nr02474k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mechanical properties of single myocytes contribute to the whole heart performance, but the measurement of mechanics in living cells at high resolution with minimal force interaction remains challenging. Angiotensin II (AngII) is a peptide hormone that regulates a number of physiological functions, including heart performance. It has also been shown to contribute to cell mechanics by inducing cell stiffening. Using non-contact high-resolution Scanning Ion Conductance Microscopy (SICM), we determine simultaneously cell topography and membrane transverse Young's modulus (YM) by a constant pressure application through a nanopipette. While applying pressure, the vertical position is recorded and a deformation map is generated from which YM can be calculated and corrected for the uneven geometry. High resolution of this method also allows studying specific membrane subdomains, such as Z-grooves and crests. We found that short-term AngII treatment reduces the transversal YM in isolated adult rat cardiomyocytes acting via an AT1 receptor. Blocking either a TGF-β1 receptor or Rho kinase abolishes this effect. Analysis of the cytoskeleton showed that AngII depletes microtubules by decreasing long-lived detyrosinated and acetylated microtubule populations. Interestingly, in the failing cardiomyocytes, which are stiffer than controls, the short-term AngII treatment also reduces the YM, thus normalizing the mechanical state of cells. This suggests that the short-term softening effect of AngII on cardiac cells is opposite to the well-characterized long-term hypertrophic effect. In conclusion, we generate a precise nanoscale indication map of location-specific transverse cortical YM within the cell and this can substantially advance our understanding of cellular mechanics in a physiological environment, for example in isolated cardiac myocytes.
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Affiliation(s)
- Pamela Swiatlowska
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - Jose L Sanchez-Alonso
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - Catherine Mansfield
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
| | - Denis Scaini
- Department of Medicine, Imperial College London, London, UK and International School for Advanced Studies, Trieste, Italy
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London, UK and Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Pavel Novak
- Department of Medicine, Imperial College London, London, UK and National University of Science and Technology, MISiS, Leninskiy prospect 4, Moscow, 119991, Russia
| | - Julia Gorelik
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK.
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17
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Abstract
Background Uremic neuropathy commonly affects patients with chronic kidney disease, with
painful sensations in the feet, followed by numbness and weakness in the
legs and hands. The symptoms usually resolve following kidney
transplantation, but the mechanisms of uremic neuropathy and associated pain
symptoms remain unknown. As blood urea levels are elevated in patients with
chronic kidney disease, we examined the morphological and functional effects
of clinically observed levels of urea on sensory neurons. Methods Rat dorsal root ganglion neurons were treated with 10 or 50 mmol/L urea for
48 h, fixed and immunostained for PGP9.5 and βIII tubulin
immunofluorescence. Neurons were also immunostained for TRPV1, TRPM8 and
Gap43 expression, and the capsaicin sensitivity of urea- or vehicle-treated
neurons was determined. Results Urea-treated neurons had degenerating neurites with diminished PGP9.5
immunofluorescence, and swollen, retracted growth cones. βIII tubulin
appeared clumped after urea treatment. After 48 hours urea treatment,
neurite lengths were significantly reduced to 60 ± 2.6% (10 mmol/L,
**P < 0.01), and to 56.2 ± 3.3% (50 mmol/L, **P < 0.01), compared with
control neurons. Fewer neurons survived urea treatment, with 70.08 ± 13.3%
remaining after 10 mmol/L (*P < 0.05) and 61.49 ± 7.4% after 50 mmol/L
urea treatment (**P < 0.01), compared with controls. The proportion of
neurons expressing TRPV1 was reduced after urea treatment, but not TRPM8
expressing neurons. In functional studies, treatment with urea resulted in
dose-dependent neuronal sensitization. Capsaicin responses were
significantly increased to 115.29 ± 3.4% (10 mmol/L, **P < 0.01) and
125.3 ± 4.2% (50 mmol/L, **P < 0.01), compared with controls.
Sensitization due to urea was eliminated in the presence of the TRPV1
inhibitor SB705498, the mitogen-activated protein kinase kinase inhibitor
PD98059, the PI3 kinase inhibitor LY294002 and the TRPM8 inhibitor
N-(3-Aminopropyl)-2-[(3-methylphenyl)methoxy]-N-(2-thienylmethyl)benzamide
(AMTB hydrochloride). Conclusion Neurite degeneration and sensitization are consistent with uremic neuropathy
and provide a disease-relevant model to test new treatments.
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Affiliation(s)
- U Anand
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Nanomedicine Research Laboratory, Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK
| | - Y Korchev
- Nanomedicine Research Laboratory, Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK
| | - P Anand
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK
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18
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Anand U, Jones B, Korchev Y, Bloom SR, Pacchetti B, Anand P, Sodergren MH. CBD Effects on TRPV1 Signaling Pathways in Cultured DRG Neurons. J Pain Res 2020; 13:2269-2278. [PMID: 32982390 PMCID: PMC7494392 DOI: 10.2147/jpr.s258433] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/11/2020] [Indexed: 01/17/2023] Open
Abstract
INTRODUCTION Cannabidiol (CBD) is reported to produce pain relief, but the clinically relevant cellular and molecular mechanisms remain uncertain. The TRPV1 receptor integrates noxious stimuli and plays a key role in pain signaling. Hence, we conducted in vitro studies, to elucidate the efficacy and mechanisms of CBD for inhibiting neuronal hypersensitivity in cultured rat sensory neurons, following activation of TRPV1. METHODS Adult rat dorsal root ganglion (DRG) neurons were cultured and supplemented with the neurotrophic factors NGF and GDNF, in an established model of neuronal hypersensitivity. Neurons were stimulated with CBD (Adven 150, EMMAC Life Sciences) at 1, 10, 100 nMol/L and 1, 10 and 50 µMol/L, 48 h after plating. In separate experiments, DRG neurons were also stimulated with capsaicin with or without CBD (1 nMol/L to10 µMol/L), in a functional calcium imaging assay. The effects of the adenylyl cyclase activator forskolin and the calcineurin inhibitor cyclosporin were determined. We also measured forskolin-stimulated cAMP levels, without and after treatment with CBD, using a homogenous time-resolved fluorescence (HTRF) assay. The results were analysed using Mann-Whitney test. RESULTS DRG neurons treated with 10 and 50 µMol/L CBD showed calcium influx, but not at lower doses. Neurons treated with capsaicin demonstrated robust calcium influx, which was dose-dependently reduced in the presence of low dose CBD (IC50 = 100 nMol/L). The inhibition or desensitization by CBD was reversed in the presence of forskolin and cyclosporin. Forskolin-stimulated cAMP levels were significantly reduced in CBD treated neurons. CONCLUSION CBD at low doses corresponding to plasma concentrations observed physiologically inhibits or desensitizes neuronal TRPV1 signalling by inhibiting the adenylyl cyclase - cAMP pathway, which is essential for maintaining TRPV1 phosphorylation and sensitization. CBD also facilitated calcineurin-mediated TRPV1 inhibition. These mechanisms may underlie nociceptor desensitization and the therapeutic effect of CBD in animal models and patients with acute and chronic pain.
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Affiliation(s)
- Uma Anand
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital, LondonW12 ONN, UK
- Correspondence: Uma Anand Email
| | - Ben Jones
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital, LondonW12 ONN, UK
| | - Yuri Korchev
- Nanomedicine Laboratory, BN5 Commonwealth Building, Imperial College London, Hammersmith Hospital, LondonW12 ONN, UK
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, Hammersmith Hospital, LondonW12 ONN, UK
| | | | - Praveen Anand
- Peripheral Neuropathy Unit, Department of Brain Sciences, Imperial College London, Hammersmith Hospital, LondonW12 ONN, UK
| | - Mikael Hans Sodergren
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital, LondonW12 ONN, UK
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19
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Takahashi Y, Zhou Y, Miyamoto T, Higashi H, Nakamichi N, Takeda Y, Kato Y, Korchev Y, Fukuma T. High-Speed SICM for the Visualization of Nanoscale Dynamic Structural Changes in Hippocampal Neurons. Anal Chem 2019; 92:2159-2167. [PMID: 31840491 DOI: 10.1021/acs.analchem.9b04775] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Dynamic reassembly of the cytoskeleton and structural changes represented by dendritic spines, cargo transport, and synapse formation are closely related to memory. However, the visualization of the nanoscale topography is challenging because of the diffraction limit of optical microscopy. Scanning ion conductance microscopy (SICM) is an effective tool for visualizing the nanoscale topography changes of the cell surface without labeling. The temporal resolution of SICM is a critical issue of live-cell time-lapse imaging. Here, we developed a new scanning method, automation region of interest (AR)-mode SICM, to select the next imaging region by predicting the location of a cell, thus improving the scanning speed of time-lapse imaging. The newly developed algorithm reduced the scanning time by half. The time-lapse images provided not only novel information about nanoscale structural changes but also quantitative information on the dendritic spine and synaptic bouton volume changes and formation process of the neural network that are closely related to memory. Furthermore, translocation of plasmalemmal precursor vesicles (ppvs), for which fluorescent labeling has not been established, were also visualized along with the rearrangement of the cytoskeleton at the growth cone.
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Affiliation(s)
- Yasufumi Takahashi
- WPI Nano Life Science Institute (WPI-NanoLSI) , Kanazawa University , Kanazawa 920-1192 , Japan.,Precursory Research for Embryonic Science and Technology (PRESTO) , Japan Science and Technology Agency (JST) , Saitama 332-0012 , Japan
| | - Yuanshu Zhou
- WPI Nano Life Science Institute (WPI-NanoLSI) , Kanazawa University , Kanazawa 920-1192 , Japan
| | - Takafumi Miyamoto
- Department Division of Electrical Engineering and Computer Science , Kanazawa University , Kanazawa 920-1192 , Japan
| | - Hiroki Higashi
- Department Division of Electrical Engineering and Computer Science , Kanazawa University , Kanazawa 920-1192 , Japan
| | - Noritaka Nakamichi
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences , Kanazawa University , Kanazawa 920-1192 , Japan
| | - Yuka Takeda
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences , Kanazawa University , Kanazawa 920-1192 , Japan
| | - Yukio Kato
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences , Kanazawa University , Kanazawa 920-1192 , Japan
| | - Yuri Korchev
- WPI Nano Life Science Institute (WPI-NanoLSI) , Kanazawa University , Kanazawa 920-1192 , Japan.,Department of Medicine , Imperial College London , London W12 0NN , United Kingdom.,National University of Science and Technology (MISiS) , Leninskiy prospect 4 , Moscow 119049 , Russia
| | - Takeshi Fukuma
- WPI Nano Life Science Institute (WPI-NanoLSI) , Kanazawa University , Kanazawa 920-1192 , Japan
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20
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Zhang Y, Takahashi Y, Hong SP, Liu F, Bednarska J, Goff PS, Novak P, Shevchuk A, Gopal S, Barozzi I, Magnani L, Sakai H, Suguru Y, Fujii T, Erofeev A, Gorelkin P, Majouga A, Weiss DJ, Edwards C, Ivanov AP, Klenerman D, Sviderskaya EV, Edel JB, Korchev Y. High-resolution label-free 3D mapping of extracellular pH of single living cells. Nat Commun 2019; 10:5610. [PMID: 31811139 PMCID: PMC6898398 DOI: 10.1038/s41467-019-13535-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/13/2019] [Indexed: 01/05/2023] Open
Abstract
Dynamic mapping of extracellular pH (pHe) at the single-cell level is critical for understanding the role of H+ in cellular and subcellular processes, with particular importance in cancer. While several pHe sensing techniques have been developed, accessing this information at the single-cell level requires improvement in sensitivity, spatial and temporal resolution. We report on a zwitterionic label-free pH nanoprobe that addresses these long-standing challenges. The probe has a sensitivity > 0.01 units, 2 ms response time, and 50 nm spatial resolution. The platform was integrated into a double-barrel nanoprobe combining pH sensing with feedback-controlled distance dependance via Scanning Ion Conductance Microscopy. This allows for the simultaneous 3D topographical imaging and pHe monitoring of living cancer cells. These classes of nanoprobes were used for real-time high spatiotemporal resolution pHe mapping at the subcellular level and revealed tumour heterogeneity of the peri-cellular environments of melanoma and breast cancer cells.
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Affiliation(s)
- Yanjun Zhang
- Department of Medicine, Imperial College London, London, W12 0NN, UK.
- Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, 300052, China.
| | - Yasufumi Takahashi
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Sung Pil Hong
- Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK
| | - Fengjie Liu
- Department of Earth Science & Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Joanna Bednarska
- Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Philip S Goff
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, SW17 0RE, UK
| | - Pavel Novak
- Department of Medicine, Imperial College London, London, W12 0NN, UK
- National University of Science and Technology "MISIS", Leninskiy prospect 4, 119991, Moscow, Russian Federation
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Sahana Gopal
- Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Iros Barozzi
- Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK
| | - Luca Magnani
- Department of Surgery and Cancer, Imperial College London, London, W12 0NN, UK
| | - Hideki Sakai
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Yoshimoto Suguru
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Takuto Fujii
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Alexander Erofeev
- National University of Science and Technology "MISIS", Leninskiy prospect 4, 119991, Moscow, Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Leninskiye gory 1-3, GSP-1, 119991, Moscow, Russian Federation
| | - Peter Gorelkin
- National University of Science and Technology "MISIS", Leninskiy prospect 4, 119991, Moscow, Russian Federation
| | - Alexander Majouga
- Department of Chemistry, Lomonosov Moscow State University, Leninskiye gory 1-3, GSP-1, 119991, Moscow, Russian Federation
| | - Dominik J Weiss
- Department of Earth Science & Engineering, Imperial College London, London, SW7 2AZ, UK
| | | | - Aleksandar P Ivanov
- Department of Chemistry, Imperial College London, Molecular Science Research Hub, London, W12 0BZ, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, London, CB2 1EW, UK
| | - Elena V Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, SW17 0RE, UK.
| | - Joshua B Edel
- Department of Chemistry, Imperial College London, Molecular Science Research Hub, London, W12 0BZ, UK.
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London, W12 0NN, UK.
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
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21
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Gopal S, Chiappini C, Penders J, Leonardo V, Seong H, Rothery S, Korchev Y, Shevchuk A, Stevens MM. Porous Silicon Nanoneedles Modulate Endocytosis to Deliver Biological Payloads. Adv Mater 2019; 31:e1806788. [PMID: 30680803 PMCID: PMC6606440 DOI: 10.1002/adma.201806788] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/09/2019] [Indexed: 05/18/2023]
Abstract
Owing to their ability to efficiently deliver biological cargo and sense the intracellular milieu, vertical arrays of high aspect ratio nanostructures, known as nanoneedles, are being developed as minimally invasive tools for cell manipulation. However, little is known of the mechanisms of cargo transfer across the cell membrane-nanoneedle interface. In particular, the contributions of membrane piercing, modulation of membrane permeability and endocytosis to cargo transfer remain largely unexplored. Here, combining state-of-the-art electron and scanning ion conductance microscopy with molecular biology techniques, it is shown that porous silicon nanoneedle arrays concurrently stimulate independent endocytic pathways which contribute to enhanced biomolecule delivery into human mesenchymal stem cells. Electron microscopy of the cell membrane at nanoneedle sites shows an intact lipid bilayer, accompanied by an accumulation of clathrin-coated pits and caveolae. Nanoneedles enhance the internalization of biomolecular markers of endocytosis, highlighting the concurrent activation of caveolae- and clathrin-mediated endocytosis, alongside macropinocytosis. These events contribute to the nanoneedle-mediated delivery (nanoinjection) of nucleic acids into human stem cells, which distribute across the cytosol and the endolysosomal system. This data extends the understanding of how nanoneedles modulate biological processes to mediate interaction with the intracellular space, providing indications for the rational design of improved cell-manipulation technologies.
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Affiliation(s)
- Sahana Gopal
- Department of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
- Department of Materials, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
| | - Ciro Chiappini
- Department of Materials, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
| | - Jelle Penders
- Department of Materials, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
| | - Vincent Leonardo
- Department of Materials, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
| | - Hyejeong Seong
- Department of Materials, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
| | - Stephen Rothery
- Facility for Imaging by Light Microscopy, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, London, SW7 2BB, UK
| | - Yuri Korchev
- Department of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Molly M Stevens
- Department of Materials, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
- Department of Bioengineering, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, Royal School of Mines, Prince Consort Road, London, SW7 2AZ, UK
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22
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Vaneev A, Alova A, Erofeev A, Gorelkin P, Aleksashkin A, Beznos O, Chesnokova N, Kost O, Majouga A, Korchev Y, Klyachko N. Detecting reactive oxygen species in biological fluids by platinum nanoelectrode applying amperometric method. BRSMU 2019. [DOI: 10.24075/brsmu.2018.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reactive oxygen species (ROS) are vital metabolites in numerous biological functions. Disorders of cellular mechanisms can cause overproduction of ROS and, subsequently, oxidative damage to DNA, proteins, cells and tissues, which is associated with the pathogenesis of a number of neurodegenerative and inflammatory diseases. Development of highly sensitive, relatively simple and fast-to-implement innovative methods to detect oxidative stress requires understanding of how such disorders relate to the level of ROS. This research aimed to apply the biological fluids' ROS detection method we have developed (using the stable platinum nanoelectrode that allows assessing the level of hydrogen peroxide (H2O2) down to 1 μM) and determine the level of H2O2 in lacrimal and intraocular fluids of rabbits, as well as to investigate how the level of H2O2 changes under the influence of antioxidant therapy. The effect superoxide dismutase (SOD) nanoparticles produce on biological fluids' ROS level was shown. The level of H2O2 in lacrimal fluid increased 10 and 30 min after instillation of SOD nanoparticles. As for the intraocular fluid, H2O2 concentration starts to grow only 30 min after instillation of SOD nanoparticles, which suggests that the they penetrate the internal structures of the eye gradually. The method seems to be of value in the context of eye diseases diagnosing and treatment.
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Affiliation(s)
| | - A.V. Alova
- Lomonosov Moscow State University, Moscow
| | - A.S. Erofeev
- National University of Science and Technology "MISiS", Moscow
| | | | | | - O.V. Beznos
- Helmholtz Institute of Ophthalmology, Moscow
| | | | - O.A. Kost
- Lomonosov Moscow State University, Moscow
| | - A.M. Majouga
- Lomonosov Moscow State University, Moscow; National University of Science and Technology "MISiS", Moscow; Dmitry Mendeleev University of Chemical Technology of Russia, Moscow
| | - Y. Korchev
- Department of Medicine, Imperial College London, London, United Kingdom; WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
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23
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Xue L, Cadinu P, Paulose Nadappuram B, Kang M, Ma Y, Korchev Y, Ivanov AP, Edel JB. Gated Single-Molecule Transport in Double-Barreled Nanopores. ACS Appl Mater Interfaces 2018; 10:38621-38629. [PMID: 30360085 PMCID: PMC6243394 DOI: 10.1021/acsami.8b13721] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Single-molecule methods have been rapidly developing with the appealing prospect of transforming conventional ensemble-averaged analytical techniques. However, challenges remain especially in improving detection sensitivity and controlling molecular transport. In this article, we present a direct method for the fabrication of analytical sensors that combine the advantages of nanopores and field-effect transistors for simultaneous label-free single-molecule detection and manipulation. We show that these hybrid sensors have perfectly aligned nanopores and field-effect transistor components making it possible to detect molecular events with up to near 100% synchronization. Furthermore, we show that the transport across the nanopore can be voltage-gated to switch on/off translocations in real time. Finally, surface functionalization of the gate electrode can also be used to fine tune transport properties enabling more active control over the translocation velocity and capture rates.
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Affiliation(s)
- Liang Xue
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Paolo Cadinu
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | | | - Minkyung Kang
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Ye Ma
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Yuri Korchev
- Department
of Medicine, Imperial College London, London W12 0NN, U.K.
| | - Aleksandar P. Ivanov
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
- E-mail: (A.P.I)
| | - Joshua B. Edel
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
- E-mail: (J.B.E.)
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24
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Cadinu P, Paulose Nadappuram B, Lee DJ, Sze JYY, Campolo G, Zhang Y, Shevchuk A, Ladame S, Albrecht T, Korchev Y, Ivanov AP, Edel JB. Single Molecule Trapping and Sensing Using Dual Nanopores Separated by a Zeptoliter Nanobridge. Nano Lett 2017; 17:6376-6384. [PMID: 28862004 PMCID: PMC5662926 DOI: 10.1021/acs.nanolett.7b03196] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/01/2017] [Indexed: 05/19/2023]
Abstract
There is a growing realization, especially within the diagnostic and therapeutic community, that the amount of information enclosed in a single molecule can not only enable a better understanding of biophysical pathways, but also offer exceptional value for early stage biomarker detection of disease onset. To this end, numerous single molecule strategies have been proposed, and in terms of label-free routes, nanopore sensing has emerged as one of the most promising methods. However, being able to finely control molecular transport in terms of transport rate, resolution, and signal-to-noise ratio (SNR) is essential to take full advantage of the technology benefits. Here we propose a novel solution to these challenges based on a method that allows biomolecules to be individually confined into a zeptoliter nanoscale droplet bridging two adjacent nanopores (nanobridge) with a 20 nm separation. Molecules that undergo confinement in the nanobridge are slowed down by up to 3 orders of magnitude compared to conventional nanopores. This leads to a dramatic improvement in the SNR, resolution, sensitivity, and limit of detection. The strategy implemented is universal and as highlighted in this manuscript can be used for the detection of dsDNA, RNA, ssDNA, and proteins.
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Affiliation(s)
- Paolo Cadinu
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Binoy Paulose Nadappuram
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Dominic J. Lee
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Jasmine Y. Y. Sze
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Giulia Campolo
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Yanjun Zhang
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Andrew Shevchuk
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Sylvain Ladame
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Tim Albrecht
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Yuri Korchev
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
| | - Aleksandar P. Ivanov
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
- E-mail:
| | - Joshua B. Edel
- Department
of Chemistry, Department of Bioengineering, Department of Medicine, Imperial College London, SW7 2AZ, United Kingdom
- E-mail: ; phone number: 020 7594 0754
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25
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Ren R, Zhang Y, Nadappuram BP, Akpinar B, Klenerman D, Ivanov AP, Edel JB, Korchev Y. Nanopore extended field-effect transistor for selective single-molecule biosensing. Nat Commun 2017; 8:586. [PMID: 28928405 PMCID: PMC5605549 DOI: 10.1038/s41467-017-00549-w] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/07/2017] [Indexed: 11/21/2022] Open
Abstract
There has been a significant drive to deliver nanotechnological solutions to biosensing, yet there remains an unmet need in the development of biosensors that are affordable, integrated, fast, capable of multiplexed detection, and offer high selectivity for trace analyte detection in biological fluids. Herein, some of these challenges are addressed by designing a new class of nanoscale sensors dubbed nanopore extended field-effect transistor (nexFET) that combine the advantages of nanopore single-molecule sensing, field-effect transistors, and recognition chemistry. We report on a polypyrrole functionalized nexFET, with controllable gate voltage that can be used to switch on/off, and slow down single-molecule DNA transport through a nanopore. This strategy enables higher molecular throughput, enhanced signal-to-noise, and even heightened selectivity via functionalization with an embedded receptor. This is shown for selective sensing of an anti-insulin antibody in the presence of its IgG isotype. Efficient detection of single molecules is vital to many biosensing technologies, which require analytical platforms with high selectivity and sensitivity. Ren et al. combine a nanopore sensor and a field-effect transistor, whereby gate voltage mediates DNA and protein transport through the nanopore.
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Affiliation(s)
- Ren Ren
- Department of Medicine, Imperial College London, London, W12 0NN, UK.,Department of Chemistry, Imperial College London, London, SW7 2AZ, UK
| | - Yanjun Zhang
- Department of Medicine, Imperial College London, London, W12 0NN, UK. .,Tianjin Neurological Institute, Tianjin Medical University General Hospital, Heping Qu, 300052, China.
| | | | - Bernice Akpinar
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | | | - Joshua B Edel
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK.
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London, W12 0NN, UK.,National University of Science & Technology MISIS, Moscow, 119049, Russia
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26
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Schobesberger S, Jönsson P, Buzuk A, Korchev Y, Siggers J, Gorelik J. Nanoscale, Voltage-Driven Application of Bioactive Substances onto Cells with Organized Topography. Biophys J 2016; 110:141-6. [PMID: 26745417 PMCID: PMC4805872 DOI: 10.1016/j.bpj.2015.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 11/26/2022] Open
Abstract
With scanning ion conductance microscopy (SICM), a noncontact scanning probe technique, it is possible both to obtain information about the surface topography of live cells and to apply molecules onto specific nanoscale structures. The technique is therefore widely used to apply chemical compounds and to study the properties of molecules on the surfaces of various cell types. The heart muscle cells, i.e., the cardiomyocytes, possess a highly elaborate, unique surface topography including transverse-tubule (T-tubule) openings leading into a cell internal system that exclusively harbors many proteins necessary for the cell’s physiological function. Here, we applied isoproterenol into these surface openings by changing the applied voltage over the SICM nanopipette. To determine the grade of precision of our application we used finite-element simulations to investigate how the concentration profile varies over the cell surface. We first obtained topography scans of the cardiomyocytes using SICM and then determined the electrophoretic mobility of isoproterenol in a high ion solution to be −7 × 10−9 m2/V s. The simulations showed that the delivery to the T-tubule opening is highly confined to the underlying Z-groove, and especially to the first T-tubule opening, where the concentration is ∼6.5 times higher compared to on a flat surface under the same delivery settings. Delivery to the crest, instead of the T-tubule opening, resulted in a much lower concentration, emphasizing the importance of topography in agonist delivery. In conclusion, SICM, unlike other techniques, can reliably deliver precise quantities of compounds to the T-tubules of cardiomyocytes
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Affiliation(s)
| | - Peter Jönsson
- Department of Chemistry, Lund University, Lund, Sweden
| | - Andrey Buzuk
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Jennifer Siggers
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Julia Gorelik
- Department of Medicine, Imperial College London, London, United Kingdom.
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27
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Marquitan M, Clausmeyer J, Actis P, Córdoba AL, Korchev Y, Mark MD, Herlitze S, Schuhmann W. Intracellular Hydrogen Peroxide Detection with Functionalised Nanoelectrodes. ChemElectroChem 2016. [DOI: 10.1002/celc.201600390] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Miriam Marquitan
- Analytical Chemistry-Center for Electrochemical Sciences (CES); Ruhr-Universität Bochum; Universitätsstraße 150 44780 Bochum Germany
| | - Jan Clausmeyer
- Analytical Chemistry-Center for Electrochemical Sciences (CES); Ruhr-Universität Bochum; Universitätsstraße 150 44780 Bochum Germany
| | - Paolo Actis
- Department of Medicine; Imperial College London; London W12 0NN UK
- School of Electronic and Electrical Engineering; University of Leeds; Leeds LS2 9JT UK
| | | | - Yuri Korchev
- Department of Medicine; Imperial College London; London W12 0NN UK
| | - Melanie D. Mark
- Department of General Zoology and Neurobiology; Ruhr-Universität Bochum; Universitätsstraße 150 44780 Bochum Germany
| | - Stefan Herlitze
- Department of General Zoology and Neurobiology; Ruhr-Universität Bochum; Universitätsstraße 150 44780 Bochum Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES); Ruhr-Universität Bochum; Universitätsstraße 150 44780 Bochum Germany
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28
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Anand U, Sinisi M, Fox M, MacQuillan A, Quick T, Korchev Y, Bountra C, McCarthy T, Anand P. Mycolactone-mediated neurite degeneration and functional effects in cultured human and rat DRG neurons: Mechanisms underlying hypoalgesia in Buruli ulcer. Mol Pain 2016; 12:12/0/1744806916654144. [PMID: 27325560 PMCID: PMC4956182 DOI: 10.1177/1744806916654144] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/16/2016] [Indexed: 01/08/2023] Open
Abstract
Background Mycolactone is a polyketide toxin secreted by the mycobacterium Mycobacterium ulcerans, responsible for the extensive hypoalgesic skin lesions characteristic of patients with Buruli ulcer. A recent pre-clinical study proposed that mycolactone may produce analgesia via activation of the angiotensin II type 2 receptor (AT2R). In contrast, AT2R antagonist EMA401 has shown analgesic efficacy in animal models and clinical trials for neuropathic pain. We therefore investigated the morphological and functional effects of mycolactone in cultured human and rat dorsal root ganglia (DRG) neurons and the role of AT2R using EMA401. Primary sensory neurons were prepared from avulsed cervical human DRG and rat DRG; 24 h after plating, neurons were incubated for 24 to 96 h with synthetic mycolactone A/B, followed by immunostaining with antibodies to PGP9.5, Gap43, β tubulin, or Mitotracker dye staining. Acute functional effects were examined by measuring capsaicin responses with calcium imaging in DRG neuronal cultures treated with mycolactone. Results Morphological effects: Mycolactone-treated cultures showed dramatically reduced numbers of surviving neurons and non-neuronal cells, reduced Gap43 and β tubulin expression, degenerating neurites and reduced cell body diameter, compared with controls. Dose-related reduction of neurite length was observed in mycolactone-treated cultures. Mitochondria were distributed throughout the length of neurites and soma of control neurons, but clustered in the neurites and soma of mycolactone-treated neurons. Functional effects: Mycolactone-treated human and rat DRG neurons showed dose-related inhibition of capsaicin responses, which were reversed by calcineurin inhibitor cyclosporine and phosphodiesterase inhibitor 3-isobutyl-1-Methylxanthine, indicating involvement of cAMP/ATP reduction. The morphological and functional effects of mycolactone were not altered by Angiotensin II or AT2R antagonist EMA401. Conclusion Mycolactone induces toxic effects in DRG neurons, leading to impaired nociceptor function, neurite degeneration, and cell death, resembling the cutaneous hypoalgesia and nerve damage in individuals with M. Ulcerans infection.
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Affiliation(s)
- U Anand
- Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK
| | - M Sinisi
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Middlesex, UK
| | - M Fox
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Middlesex, UK
| | - A MacQuillan
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Middlesex, UK
| | - T Quick
- Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Middlesex, UK
| | - Y Korchev
- Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK
| | - C Bountra
- University of Oxford Structural Genomics Consortium, Headington, Oxford, UK
| | - T McCarthy
- Spinifex Pharmaceuticals Pty Ltd, St. Preston, VIC, Australia
| | - P Anand
- Department of Medicine, Imperial College London, Hammersmith Hospital, London, UK
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29
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Zhang Y, Clausmeyer J, Babakinejad B, Córdoba AL, Ali T, Shevchuk A, Takahashi Y, Novak P, Edwards C, Lab M, Gopal S, Chiappini C, Anand U, Magnani L, Coombes RC, Gorelik J, Matsue T, Schuhmann W, Klenerman D, Sviderskaya EV, Korchev Y. Spearhead Nanometric Field-Effect Transistor Sensors for Single-Cell Analysis. ACS Nano 2016; 10:3214-3221. [PMID: 26816294 PMCID: PMC4933202 DOI: 10.1021/acsnano.5b05211] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Nanometric field-effect-transistor (FET) sensors are made on the tip of spear-shaped dual carbon nanoelectrodes derived from carbon deposition inside double-barrel nanopipettes. The easy fabrication route allows deposition of semiconductors or conducting polymers to comprise the transistor channel. A channel from electrodeposited poly pyrrole (PPy) exhibits high sensitivity toward pH changes. This property is exploited by immobilizing hexokinase on PPy nano-FETs to give rise to a selective ATP biosensor. Extracellular pH and ATP gradients are key biochemical constituents in the microenvironment of living cells; we monitor their real-time changes in relation to cancer cells and cardiomyocytes. The highly localized detection is possible because of the high aspect ratio and the spear-like design of the nano-FET probes. The accurately positioned nano-FET sensors can detect concentration gradients in three-dimensional space, identify biochemical properties of a single living cell, and after cell membrane penetration perform intracellular measurements.
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Affiliation(s)
- Yanjun Zhang
- Department of Medicine, London W12 0NN, United Kingdom
| | - Jan Clausmeyer
- Analytical Chemistry—Center for Electrochemical Sciences (CES), Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | | | | | - Tayyibah Ali
- Department of Medicine, London W12 0NN, United Kingdom
| | | | - Yasufumi Takahashi
- Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Pavel Novak
- School of Engineering and Materials Science, Queen Mary, University of London, London E1 4NS, United Kingdom
| | | | - Max Lab
- Department of Cardiac Medicine, National Heart and Lung Institute, London W12 0NN, United Kingdom
| | - Sahana Gopal
- Department of Medicine, London W12 0NN, United Kingdom
| | - Ciro Chiappini
- Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom
| | - Uma Anand
- Department of Medicine, London W12 0NN, United Kingdom
| | - Luca Magnani
- Department of Surgery and Cancer, Imperial College London, London W12 0NN, United Kingdom
| | - R. Charles Coombes
- Department of Surgery and Cancer, Imperial College London, London W12 0NN, United Kingdom
| | - Julia Gorelik
- Department of Cardiac Medicine, National Heart and Lung Institute, London W12 0NN, United Kingdom
| | - Tomokazu Matsue
- Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Wolfgang Schuhmann
- Analytical Chemistry—Center for Electrochemical Sciences (CES), Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- Corresponding Authors (Wolfgang Schuhmann)
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- (David Klenerman)
| | - Elena V. Sviderskaya
- Cell Biology and Genetics Research Centre, St. George's
University of London, London SW17 0RE, United Kingdom
- (Elena V. Sviderskaya)
| | - Yuri Korchev
- Department of Medicine, London W12 0NN, United Kingdom
- (Yuri Korchev)
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Abstract
Understanding the behavioral properties of single molecules or larger scale populations interacting with single molecules is currently a hotly pursued topic in nanotechnology. This arises from the potential such techniques have in relation to applications such as targeted drug delivery, early stage detection of disease, and drug screening. Although label and label-free single molecule detection strategies have existed for a number of years, currently lacking are efficient methods for the controllable delivery of single molecules in aqueous environments. In this article we show both experimentally and from simulations that nanopipets in conjunction with asymmetric voltage pulses can be used for label-free detection and delivery of single molecules through the tip of a nanopipet with "on-demand" timing resolution. This was demonstrated by controllable delivery of 5 kbp and 10 kbp DNA molecules from solutions with concentrations as low as 3 pM.
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Affiliation(s)
- Aleksandar P Ivanov
- †Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Paolo Actis
- ‡Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Peter Jönsson
- §Department of Chemistry, Lund University, Lund SE-221 00, Sweden
- ∥Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - David Klenerman
- ∥Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Yuri Korchev
- ‡Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Joshua B Edel
- †Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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López-Córdoba A, Jönsson P, Babakinejad B, Actis P, Novak P, Yasufumi T, Shevchuck A, Anand U, Anand P, Drews A, Ferrer-Montiel A, Klenerman D, Korchev Y. SICM-Based Nanodelivery System for Local TRPV1 Stimulation. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.1808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Taberner FJ, López-Córdoba A, Fernández-Ballester G, Korchev Y, Ferrer-Montiel A. The region adjacent to the C-end of the inner gate in transient receptor potential melastatin 8 (TRPM8) channels plays a central role in allosteric channel activation. J Biol Chem 2014; 289:28579-94. [PMID: 25157108 DOI: 10.1074/jbc.m114.577478] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The ability of transient receptor potential (TRP) channels to sense and respond to environmental and endogenous cues is crucial in animal sensory physiology. The molecular mechanism of channel gating is yet elusive. The TRP box, a conserved region in the N-end of the C terminus domain, has been signaled as pivotal for allosteric activation in TRP channels. Here, we have examined the role of the linker region between the TRPM8 inner gate and the TRP box (referred to as the S6-TRP box linker) to identify structural determinants of channel gating. Stepwise substitutions of segments in the S6-TRP box linker of TRPM8 channel with the cognate TRPV1 channel sequences produced functional chimeric channels, and identified Tyr(981) as a central molecular determinant of channel function. Additionally, mutations in the 986-990 region had a profound impact on channel gating by voltage and menthol, as evidenced by the modulation of the conductance-to-voltage (G-V) relationships. Simulation of G-V curves using an allosteric model for channel activation revealed that these mutations altered the allosteric constants that couple stimuli sensing to pore opening. A molecular model of TRPM8, based on the recently reported TRPV1 structural model, showed that Tyr(981) may lie in a hydrophobic pocket at the end of the S6 transmembrane segment and is involved in inter-subunit interactions with residues from neighbor subunits. The 986-990 region holds intrasubunit interactions between the TRP domain and the S4-S5 linker. These findings substantiate a gating mechanism whereby the TRP domain acts as a coupling domain for efficient channel opening. Furthermore, they imply that protein-protein interactions of the TRP domain may be targets for channel modulation and drug intervention.
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Affiliation(s)
- Francisco José Taberner
- From the Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain
| | - Ainara López-Córdoba
- From the Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain
| | | | - Yuri Korchev
- the Imperial College School of Medicine, SW7 2AZ London, United Kingdom, and
| | - Antonio Ferrer-Montiel
- From the Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain, the Unidad de Biofísica, UPV/EHU, CSIC, 48940 Leioa, Spain
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Bhargava A, Lin X, Novak P, Mehta K, Korchev Y, Delmar M, Gorelik J. Super-resolution scanning patch clamp reveals clustering of functional ion channels in adult ventricular myocyte. Circ Res 2013; 112:1112-1120. [PMID: 23438901 DOI: 10.1161/circresaha.111.300445] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Compartmentation of ion channels on the cardiomyocyte surface is important for electric propagation and electromechanical coupling. The specialized T-tubule and costameric structures facilitate spatial coupling of various ion channels and receptors. Existing methods such as immunofluorescence and patch clamp techniques are limited in their ability to localize functional ion channels. As such, a correlation between channel protein location and channel function remains incomplete. OBJECTIVE To validate a method that permits routine imaging of the topography of a live cardiomyocyte and study clustering of functional ion channels from a specific microdomain. METHODS AND RESULTS We used scanning ion conductance microscopy and conventional cell-attached patch clamp with a software modification that allows controlled increase of pipette tip diameter. The sharp nanopipette used for topography scan was modified into a larger patch pipette that could be positioned with nanoscale precision to a specific site of interest (crest, groove, or T-tubules of cardiomyocytes) and sealed to the membrane for cell-attached recording of ion channels. Using this method, we significantly increased the probability of detecting activity of L-type calcium channels in the T-tubules of ventricular cardiomyocytes. We also demonstrated that active sodium channels do not distribute homogenously on the sarcolemma instead, they segregate into clusters of various densities, most crowded in the crest region, that are surrounded by areas virtually free of functional sodium channels. CONCLUSIONS Our new method substantially increases the throughput of recording location-specific functional ion channels on the cardiomyocyte sarcolemma, thereby allowing characterization of ion channels in relation to the microdomain where they reside.
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Affiliation(s)
- Anamika Bhargava
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, UK
| | - Xianming Lin
- The Leon H Charney Division of Cardiology, New York University School of Medicine, New York, NY, USA
| | - Pavel Novak
- Department of Medicine, Imperial College London, UK
| | - Kinneri Mehta
- The Leon H Charney Division of Cardiology, New York University School of Medicine, New York, NY, USA
| | - Yuri Korchev
- Department of Medicine, Imperial College London, UK
| | - Mario Delmar
- The Leon H Charney Division of Cardiology, New York University School of Medicine, New York, NY, USA
| | - Julia Gorelik
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, UK
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Babakinejad B, Yasufumi T, Yasufumi T, Korchev Y, Actis P. Development of Carbon Nano-Heater: Stimulation of Sensory Neurons for Functional Study of Heat Sensitive Channels. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.2870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Babakinejad B, Yasufumi T, Jönsson P, Novak P, Shevchuk A, Anand U, Klenerman D, Korchev Y. Quantitative Characterization of Local Chemical Delivery through Nanopipette. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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37
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Anand U, Otto WR, Sanchez-Herrera D, Facer P, Yiangou Y, Korchev Y, Birch R, Benham C, Bountra C, Chessell IP, Anand P. Cannabinoid receptor CB2 localisation and agonist-mediated inhibition of capsaicin responses in human sensory neurons. Pain 2008; 138:667-680. [DOI: 10.1016/j.pain.2008.06.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 04/14/2008] [Accepted: 06/02/2008] [Indexed: 10/21/2022]
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Piper JD, Li C, Lo CJ, Berry R, Korchev Y, Ying L, Klenerman D. Characterization and Application of Controllable Local Chemical Changes Produced by Reagent Delivery from a Nanopipet. J Am Chem Soc 2008; 130:10386-93. [DOI: 10.1021/ja8022253] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kemp SJ, Thorley AJ, Gorelik J, Seckl MJ, O'Hare MJ, Arcaro A, Korchev Y, Goldstraw P, Tetley TD. Immortalization of human alveolar epithelial cells to investigate nanoparticle uptake. Am J Respir Cell Mol Biol 2008; 39:591-7. [PMID: 18539954 DOI: 10.1165/rcmb.2007-0334oc] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Primary human alveolar type 2 (AT2) cells were immortalized by transduction with the catalytic subunit of telomerase and simian virus 40 large-tumor antigen. Characterization by immunochemical and morphologic methods demonstrated an AT1-like cell phenotype. Unlike primary AT2 cells, immortalized cells no longer expressed alkaline phosphatase, pro-surfactant protein C, and thyroid transcription factor-1, but expressed increased caveolin-1 and receptor for advanced glycation end products (RAGE). Live cell imaging using scanning ion conductance microscopy showed that the cuboidal primary AT2 cells were approximately 15 microm and enriched with surface microvilli, while the immortal AT1 cells were attenuated more than 40 microm, resembling these cells in situ. Transmission electron microscopy highlighted the attenuated morphology and showed endosomal vesicles in some immortal AT1 cells (but not primary AT2 cells) as found in situ. Particulate air pollution exacerbates cardiopulmonary disease. Interaction of ultrafine, nano-sized particles with the alveolar epithelium and/or translocation into the cardiovasculature may be a contributory factor. We hypothesized differential uptake of nanoparticles by AT1 and AT2 cells, depending on particle size and surface charge. Uptake of 50-nm and 1-microm fluorescent latex particles was investigated using confocal microscopy and scanning surface confocal microscopy of live cells. Fewer than 10% of primary AT2 cells internalized particles. In contrast, 75% immortal AT1 cells internalized negatively charged particles, while less than 55% of these cells internalized positively charged particles; charge, rather than size, mattered. The process was rapid: one-third of the total cell-associated negatively charged 50-nm particle fluorescence measured at 24 hours was internalized during the first hour. AT1 cells could be important in translocation of particles from the lung into the circulation.
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Affiliation(s)
- Sarah J Kemp
- Lung Cell Biology, National Heart and Lung Institute, Imperial College, London, UK
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Abstract
One grand challenge in current biology is to understand how individual cellular molecules interact together to form a functioning living cell. This requires new methods to image a live cell on the nanoscale. The scanned nanopipette can be used to obtain high resolution noncontact images of the surface of live cells under physiological conditions and has been used to develop a family of related methods that allow mapping of cell function on the nanoscale, and hence allow the relationship between cell structure and function to be probed. This is a powerful method to bridge the current gap between high resolution structures of individual molecular complexes and low resolution imaging of live cell structure and function.
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Affiliation(s)
- David Klenerman
- University of Cambridge, Department of Chemistry, Cambridge, UK.
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41
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Bruckbauer A, James P, Zhou D, Yoon JW, Excell D, Korchev Y, Jones R, Klenerman D. Nanopipette delivery of individual molecules to cellular compartments for single-molecule fluorescence tracking. Biophys J 2007; 93:3120-31. [PMID: 17631532 PMCID: PMC2025666 DOI: 10.1529/biophysj.107.104737] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have developed a new method, using a nanopipette, for controlled voltage-driven delivery of individual fluorescently labeled probe molecules to the plasma membrane which we used for single-molecule fluorescence tracking (SMT). The advantages of the method are 1), application of the probe to predefined regions on the membrane; 2), release of only one or a few molecules onto the cell surface; 3), when combined with total internal reflection fluorescence microscopy, very low background due to unbound molecules; and 4), the ability to first optimize the experiment and then repeat it on the same cell. We validated the method by performing an SMT study of the diffusion of individual membrane glycoproteins labeled with Atto 647-wheat germ agglutin in different surface domains of boar spermatozoa. We found little deviation from Brownian diffusion with a mean diffusion coefficient of 0.79 +/- 0.04 microm(2)/s in the acrosomal region and 0.10 +/- 0.02 microm(2)/s in the postacrosomal region; this difference probably reflects different membrane structures. We also showed that we can analyze diffusional properties of different subregions of the cell membrane and probe for the presence of diffusion barriers. It should be straightforward to extend this new method to other probes and cells, and it can be used as a new tool to investigate the cell membrane.
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Affiliation(s)
- Andreas Bruckbauer
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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Zhang Y, Sanchez D, Gorelik J, Klenerman D, Lab M, Edwards C, Korchev Y. Basolateral P2X4-like receptors regulate the extracellular ATP-stimulated epithelial Na+ channel activity in renal epithelia. Am J Physiol Renal Physiol 2007; 292:F1734-40. [PMID: 17356127 DOI: 10.1152/ajprenal.00382.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Extracellular ATP initiates potent effects on sodium transport across renal epithelia through membrane-associated purinergic receptors. Dependent on the location of these receptors, ATP either inhibits or stimulates sodium reabsorption. Using A6 cells, transepithelial electrical resistance measurements, and scanning ion conductance microscopy, we have identified the purinergic receptors involved in the stimulatory action on the epithelial cell basolateral plasma membrane. Addition of the potent P2X(4) receptor agonist 2-methylthio-ATP (2MeSATP) to the basolateral side of the A6 monolayer stimulated amiloride-sensitive sodium conductance and produced similar cell morphological changes to those found with ATPgammaS, aldosterone, or hypotonic stress. The agonist potency order determined by sodium conductance changes of the monolayer was: 2MeSATP >or= ATPgammaS > CTP, a similar agonist potency profile to that of cloned P2X(4) receptors but with higher sensitivity for beta, gamma-methylene-ATP and alpha,beta-methylene-ATP. We further demonstrated that the ATP effect on sodium transport was potentiated by ivermectin, not blocked by suramin and PPADS, enhanced by Zn(2+) but not by Cu(2+), and significantly reduced but not totally inhibited by brilliant blue G. These results led us to conclude that basolateral P2X(4)-like receptors were involved. We suggest that there is a reciprocal purinergic system acting both at a basolateral and apical location for control of Na(+) transport. This requires a mechanism within the cell that leads to either basolateral or apical ATP release to regulate renal tubular function.
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Affiliation(s)
- Yanjun Zhang
- Division of Medicine, Imperial College London, London, UK
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Gorelik J, Yang LQ, Zhang Y, Lab M, Korchev Y, Harding SE. A novel Z-groove index characterizing myocardial surface structure. Cardiovasc Res 2006; 72:422-9. [PMID: 17054929 DOI: 10.1016/j.cardiores.2006.09.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 09/12/2006] [Accepted: 09/13/2006] [Indexed: 10/24/2022] Open
Abstract
OBJECTIVE The role of t-tubule structures in excitation-contraction coupling of ventricular myocytes has been investigated by disruption using prolonged culture, or osmotic shock with formamide. We have used a new method, the Scanning Ion Conductance Microscope (SICM), to investigate in more detail the changes in surface structure of live myocytes during these interventions and to relate them to contractile effects. METHODS Freshly isolated ventricular myocytes from adult rat hearts were either incubated with formamide, then washed to produce osmotic shock, or put into culture for 2, 4 and 7 days. Contractile characteristics of single myocytes were then measured using the IonOptix system, and in parallel imaged using the SICM which produces a 3-dimensional topographical representation of the cell surface. Loss of t-tubules was quantitated with confocal microscopy after staining with the membrane dye di-8-ANNEPS, and sarcomere structure revealed by immunocytochemical detection of alpha-actinin. RESULTS Detubulation was produced by either method, with formamide equivalent to 4 day culture in quantitative measures of ANNEPS t-tubule/membrane ratio. SICM images confirmed the loss of t-tubule indentations. Disruption of the Z-groove structure and flattening of the surface were also noted with formamide and, to a lesser extent, culture. A novel Z-groove index was introduced to describe this effect more quantitatively. Contraction and relaxation were impaired by the detubulation methods, but formamide had a markedly greater depressant effect on contraction amplitude than equivalent detubulation by culture. CONCLUSION Changes in contraction amplitude after detubulation with formamide were more closely related to the alteration in Z-groove structure than loss of t-tubules alone. As well as disrupting t-tubule-induced excitation and calcium movements, formamide may alter the transmission of contraction in the myocyte by interference with sarcomere attachment at the Z-line.
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Affiliation(s)
- Julia Gorelik
- National Heart and Lung Institute, Imperial College, London SW3 6LY, UK
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Sánchez D, Anand U, Gorelik J, Benham CD, Bountra C, Lab M, Klenerman D, Birch R, Anand P, Korchev Y. Localized and non-contact mechanical stimulation of dorsal root ganglion sensory neurons using scanning ion conductance microscopy. J Neurosci Methods 2006; 159:26-34. [PMID: 16887195 DOI: 10.1016/j.jneumeth.2006.06.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 06/20/2006] [Accepted: 06/21/2006] [Indexed: 01/01/2023]
Abstract
Mechanosensitive ion channels convert external mechanical force into electrical and chemical signals in cells, but their physiological function in different tissues is not clearly understood. One reason for this is that there is as yet no satisfactory physiological method to stimulate these channels in living cells. Using the nanopipette-probe of the Scanning Ion Conductance Microscope (SICM), we have developed a new technique to apply local mechanical stimulus to living cells to an area of about 0.385 microm2, determined by the pipette diameter. Our method prevents any physical contact and damage to the cell membrane by use of a pressure jet applied via the nanopipette. The study used whole-cell patch-clamp recordings and measurements of intracellular Ca2+ concentration to validate the application of the mechanical stimulation protocols in human and rat dorsal root ganglia (DRG) sensory neurons. We were able, for the first time, to produce a non-contact, controlled mechanical stimulation on living neurites of human DRG neurons. Our methods will enable the identification and characterisation of compounds being developed for the treatment of clinical mechanical hypersensitivity states.
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Affiliation(s)
- Daniel Sánchez
- Imperial College Faculty of Medicine, London Centre for Nanotechnology, Division of Medicine, 5th floor MRC Clinical Sciences Centre, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
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Yang LQ, Gorelik J, Korchev Y, Harding S. Increase in β1AR-Gi coupling after detubulation in rat ventricular myocytes. J Mol Cell Cardiol 2006. [DOI: 10.1016/j.yjmcc.2006.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Gorelik J, Patel P, Ng'andwe C, Vodyanoy I, Diakonov I, Lab M, Korchev Y, Williamson C. Genes encoding bile acid, phospholipid and anion transporters are expressed in a human fetal cardiomyocyte culture. BJOG 2006; 113:552-8. [PMID: 16637898 DOI: 10.1111/j.1471-0528.2006.00918.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To establish a human fetal cardiomyocyte culture and to investigate whether the genes that encode transporters that may influence influx or efflux of bile acids are expressed in human fetal cardiomyocytes. DESIGN Laboratory study. SETTING Imperial College London. SAMPLE Six fetal hearts were obtained at the time of termination of pregnancy at 12-13 weeks of gestation and used to generate primary human cardiomyocyte cultures. METHODS To confirm the presence of cardiomyocytes, the cells were incubated with monoclonal antibodies to sarcomeric alpha-actinin and anticardiac myosin heavy chain. Real-time reverse transcription polymerase chain reaction was used to establish whether transcripts of genes that may influence bile acid transport are present in the culture (NTCP, BSEP, MDR3, FIC1, MRP2, MRP3, OATP-A, OATP-C, OATP-D, OATP-E) and whether taurocholate administration alters messenger RNA (mRNA) expression. MAIN OUTCOME MEASURES Relative mRNA expression of genes of interest. RESULTS Real-time polymerase chain reaction demonstrated the presence of mRNA for BSEP, MDR3, FIC1, OATP-C, OATP-D and OATP-E in fetal heart. Four transcripts remained in the cardiomyocyte culture (BSEP, MDR3, FIC1 and OATP-D), and we demonstrated the influence of taurocholate on gene expression. CONCLUSIONS We have developed an in vitro model of the fetal heart that may be used for studies of the cardiac effect of endobiotics, e.g. bile acids, or of specific agents that may be used to treat the mother or fetus in pregnancy.
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Affiliation(s)
- J Gorelik
- Division of Medicine, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Campus, London, UK
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Gorelik J, Zhang Y, Sánchez D, Shevchuk A, Frolenkov G, Lab M, Klenerman D, Edwards C, Korchev Y. Aldosterone acts via an ATP autocrine/paracrine system: the Edelman ATP hypothesis revisited. Proc Natl Acad Sci U S A 2005; 102:15000-5. [PMID: 16230642 PMCID: PMC1257717 DOI: 10.1073/pnas.0507008102] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aldosterone, the most important sodium-retaining hormone, was first characterized >50 years ago. However, despite numerous studies including the classical work of Isidore S. "Izzy" Edelman showing that aldosterone action depended on ATP production, the mechanism by which it activates sodium reabsorption via the epithelial sodium channel remains unclear. Here, we report experiments that suggest that one of the key steps in aldosterone action is via an autocrine/paracrine system. The hormone stimulates ATP release from the basolateral side of the target kidney cell. Prevention of ATP accumulation or its removal blocks aldosterone action. ATP then acts via a purinergic mechanism to produce contraction of small groups of adjacent epithelial cells. Patch clamping demonstrates that it is these contracted cells that have channel activity. With progressive recruitment of contracting cells, there is then a parallel increase in transepithelial electrical conductance. In common with other stimuli of sodium transport, this pathway involves phosphatidylinositol 3-kinase. Inhibition of phosphatidylinositol 3-kinase blocks both cell contraction and conductance. We put forward the hypothesis that redistribution of the cell volume caused by the lateral contraction results in apical swelling and that this change, in turn, disrupts the epithelial sodium channel interaction with the F-actin cytoskeleton, opening the channel and hence increasing sodium transport.
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Affiliation(s)
- Julia Gorelik
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Zhang Y, Gorelik J, Sanchez D, Shevchuk A, Lab M, Vodyanoy I, Klenerman D, Edwards C, Korchev Y. Scanning ion conductance microscopy reveals how a functional renal epithelial monolayer maintains its integrity. Kidney Int 2005; 68:1071-7. [PMID: 16105037 DOI: 10.1111/j.1523-1755.2005.00499.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND To function as a transport barrier a renal tubule epithelial monolayer needs to maintain its integrity when, sudden hypertonic stress causes cell shrinkage, new cells are added, or cells in the monolayer die. However, the mechanism used to achieve this is largely unknown. Scanning ion conductance microscopy (SICM) has been shown to be suitable for imaging the surface of live renal cells with high topographic resolution, and can be used to elucidate how a functional renal epithelial monolayer maintains its integrity. METHODS SICM was used for high spatial resolution topographic imaging of Xenopuslaevis renal epithelial A6 cells cultured on membrane filter inserts. RESULTS The SICM images of A6 cells showed that the epithelial monolayer maintains its integrity under hypertonic stress, and during cell division and death. Sequential SICM topographic images revealed detailed structural changes and their time course for these protective processes, which involve highly cooperative cell movement. Some "balloon-like" structures were observed at susceptible tight junction regions, which were proposed to help cell maintaining the monolayer permeability integrity. CONCLUSION SICM is a powerful tool for research on living renal epithelial cells, and has been used to elucidate how a functional epithelial monolayer maintains its integrity. Using this technique we have observed that during hypertonic stress and regeneration, an organized sequence of events protect the loss of integrity of monolayer so that tight junctions and cell-cell contact are maintained and disruption to the function of whole monolayer is prevented.
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Affiliation(s)
- Yanjun Zhang
- Division of Medicine, Imperial College London, London, United Kingdom
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Ying L, Bruckbauer A, Zhou D, Gorelik J, Shevchuk A, Lab M, Korchev Y, Klenerman D. The scanned nanopipette: a new tool for high resolution bioimaging and controlled deposition of biomolecules. Phys Chem Chem Phys 2005; 7:2859-66. [PMID: 16189604 DOI: 10.1039/b506743j] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The boundary between the physical and biological sciences has been eroded in recent years with new physical methods applied to biology and biological molecules being used for new physical purposes. We have pioneered the application of a form of scanning probe microscopy based on a scanned nanopipette, originally developed by Hansma and co-workers, for reliable non-contact imaging over the surface of a live cell. We have found that the nanopipette can also be used for controlled local voltage-driven application of reagents or biomolecules and this can be used for controlled deposition and the local delivery of probes for mapping of specific species. In this article we review this progress, focussing on the physical principles and new phenomena that we have observed, and then outline the future applications that are now possible.
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Affiliation(s)
- Liming Ying
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge, UK
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Gu Y, Kirkman-Brown JC, Korchev Y, Barratt CLR, Publicover SJ. Multi-state, 4-aminopyridine-sensitive ion channels in human spermatozoa. Dev Biol 2004; 274:308-17. [PMID: 15385161 DOI: 10.1016/j.ydbio.2004.06.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Revised: 05/20/2004] [Accepted: 06/24/2004] [Indexed: 11/30/2022]
Abstract
Although ion channels are known to be pivotal to sperm function, the technical difficulty of applying electrophysiological techniques to spermatozoa has prevented significant progress in this area. This is due to the cell size and angular shape in combination with their motility. Using a refined technique, specifically for patch clamping spermatozoa, we have made recordings from human cells. This technique permitted approaches which enable functional analysis of sperm ion channels, including acquisition of inside-out patches, generation of averaged currents, and observation of the effects of pharmacological manipulation during prolonged recordings. As well as a low conductance (7 pS) channel and a 25-pS channel, the most striking finding was the presence of very high conductance, 4-aminopyridine-sensitive multistate channels resembling the non-selective cation channel of sea urchin and mouse spermatozoa. Application of 2 mM 4-aminopyridine (a dose sufficient to cause channel blockade) caused an instant and dramatic transition of motility in the sperm population increasing hyperactivated motility by more than 10-fold as assessed by computer-assisted semen analysis. Combined application of patch clamp and pharmacological investigation of mature sperm cells and will permit rapid advances in our understanding the role of ion channels in sperm function.
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Affiliation(s)
- Y Gu
- MRC Clinical Sciences Centre, Division of Medicine, Hammersmith Campus, Imperial College School of Medicine, W12 0NN, London, UK
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