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Rapedius M, Obergrussberger A, Humphries ESA, Scholz S, Rinke-Weiss I, Goetze TA, Brinkwirth N, Rotordam MG, Strassmaier T, Randolph A, Friis S, Liutkute A, Seibertz F, Voigt N, Fertig N. There is no F in APC: Using physiological fluoride-free solutions for high throughput automated patch clamp experiments. Front Mol Neurosci 2022; 15:982316. [PMID: 36072300 PMCID: PMC9443850 DOI: 10.3389/fnmol.2022.982316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
Fluoride has been used in the internal recording solution for manual and automated patch clamp experiments for decades because it helps to improve the seal resistance and promotes longer lasting recordings. In manual patch clamp, fluoride has been used to record voltage-gated Na (NaV) channels where seal resistance and access resistance are critical for good voltage control. In automated patch clamp, suction is applied from underneath the patch clamp chip to attract a cell to the hole and obtain a good seal. Since the patch clamp aperture cannot be moved to improve the seal like the patch clamp pipette in manual patch clamp, automated patch clamp manufacturers use internal fluoride to improve the success rate for obtaining GΩ seals. However, internal fluoride can affect voltage-dependence of activation and inactivation, as well as affecting internal second messenger systems and therefore, it is desirable to have the option to perform experiments using physiological, fluoride-free internal solution. We have developed an approach for high throughput fluoride-free recordings on a 384-well based automated patch clamp system with success rates >40% for GΩ seals. We demonstrate this method using hERG expressed in HEK cells, as well as NaV1.5, NaV1.7, and KCa3.1 expressed in CHO cells. We describe the advantages and disadvantages of using fluoride and provide examples of where fluoride can be used, where caution should be exerted and where fluoride-free solutions provide an advantage over fluoride-containing solutions.
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Affiliation(s)
- Markus Rapedius
- Nanion Technologies GmbH, Munich, Germany
- *Correspondence: Markus Rapedius,
| | | | | | | | | | | | | | | | | | | | | | - Aiste Liutkute
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research, Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells”, University of Göttingen, Göttingen, Germany
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research, Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells”, University of Göttingen, Göttingen, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
- German Center for Cardiovascular Research, Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells”, University of Göttingen, Göttingen, Germany
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2
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Obergrussberger A, Rinke-Weiß I, Goetze TA, Rapedius M, Brinkwirth N, Becker N, Rotordam MG, Hutchison L, Madau P, Pau D, Dalrymple D, Braun N, Friis S, Pless SA, Fertig N. The suitability of high throughput automated patch clamp for physiological applications. J Physiol 2021; 600:277-297. [PMID: 34555195 DOI: 10.1113/jp282107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/16/2021] [Indexed: 01/18/2023] Open
Abstract
Although automated patch clamp (APC) devices have been around for many years and have become an integral part of many aspects of drug discovery, high throughput instruments with gigaohm seal data quality are relatively new. Experiments where a large number of compounds are screened against ion channels are ideally suited to high throughput APC, particularly when the amount of compound available is low. Here we evaluate different APC approaches using a variety of ion channels and screening settings. We have performed a screen of 1920 compounds on GluN1/GluN2A NMDA receptors for negative allosteric modulation using both the SyncroPatch 384 and FLIPR. Additionally, we tested the effect of 36 arthropod venoms on NaV 1.9 using a single 384-well plate on the SyncroPatch 384. As an example for mutant screening, a range of acid-sensing ion channel variants were tested and the success rate increased through fluorescence-activated cell sorting (FACS) prior to APC experiments. Gigaohm seal data quality makes the 384-format accessible to recording of primary and stem cell-derived cells on the SyncroPatch 384. We show recordings in voltage and current clamp modes of stem cell-derived cardiomyocytes. In addition, the option of intracellular solution exchange enabled investigations into the effects of intracellular Ca2+ and cAMP on TRPC5 and HCN2 currents, respectively. Together, these data highlight the broad applicability and versatility of APC platforms and also outlines some limitations of the approach. KEY POINTS: High throughput automated patch clamp (APC) can be used for a variety of applications involving ion channels. Lower false positive rates were achieved using automated patch clamp versus a fluorometric imaging plate reader (FLIPR) in a high throughput compound screen against NMDA receptors. Genetic variants and mutations can be screened on a single 384-well plate to reduce variability of experimental parameters. Intracellular solution can be perfused to investigate effects of ions and second messenger systems without the need for excised patches. Primary cells and stem cell-derived cells can be used on high throughput APC with reasonable success rates for cell capture, voltage clamp measurements and action potential recordings in current clamp mode.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Nina Braun
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
| | | | - Stephan A Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
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3
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Nembo EN, Hescheler J, Nguemo F. Stem cells in natural product and medicinal plant drug discovery-An overview of new screening approaches. Biomed Pharmacother 2020; 131:110730. [PMID: 32920519 DOI: 10.1016/j.biopha.2020.110730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 01/14/2023] Open
Abstract
Natural products remain a rich source of new drugs, and the search for bioactive molecules from nature continues to play an important role in the development of new medicines. Also, there is increasing use of herbal medicines for the treatment of a plethora of diseases, and demands for more scientific evidence for their efficacy and safety remains a huge challenge. The propensity of stem cells to differentiate into almost every cell type not only holds promise for the delivery of cell-based therapies for currently incurable diseases or a useful tool in studying cell physiology and pathophysiology. Increasingly, stem cells are becoming an important tool in preclinical drug screening and toxicity testing. In this review, we examine the scientific advances made towards the use of pluripotent stem cells as a model for the screening of plant-based medicines. The combination of well-established in vitro electrophysiological and a plethora of toxicogenomic technologies, together with the optimisation of culture methods of herbal plants and pluripotent stem cells can be explored to establish the basis for efficacy, and tissue/organ-based toxicities of many currently used medicinal plants whose efficacies and toxicities remain unknown.
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Affiliation(s)
- Erastus Nembu Nembo
- Institute of Neurophysiology, University of Cologne, 50931, Cologne, Germany
| | - Jürgen Hescheler
- Institute of Neurophysiology, University of Cologne, 50931, Cologne, Germany
| | - Filomain Nguemo
- Institute of Neurophysiology, University of Cologne, 50931, Cologne, Germany.
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4
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Zheng T, Baaken G, Behrends JC, Rühe J. Microelectrochemical cell arrays for whole-cell currents recording through ion channel proteins based on trans-electroporation approach. Analyst 2019; 145:197-205. [PMID: 31730143 DOI: 10.1039/c9an01737b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High electrostability and long life-time of planar chip technology are crucial for electrophysiological measurements such as ionic current recording through ion channel proteins embedded in biological cell membrane. In this paper, we propose a novel planar microchip integrated with microelectrochemical cell array toward to a feasible solution for ion channel screening with high resolution and long life-time. In order to reduce the interference from the leakage currents, a synthetic lipid bilayer is applied to form a high sealing resistance. The whole-cell electrical access can be constructed via electroporating the lipid bilayer in close proximity to the cell membrane. Parameters of electroporation including amplitude and time scale are firstly optimized by using parallel electroporation to the lipid bilayers. In this approach, individual cells can be trapped to the target positions by applying dielectrophoresis (DEP) manipulation. Poly(ethylene glycol) (PEG) is employed with low concentration to facilitate the closed contact between the cells and the lipid bilayer to increase the efficiency of the whole-cell mode construction. Through this chip based method, stable current recordings through inward rectifier potassium (Kir) ion channels embedded in rat basophilic leukemia (RBL-1) cell membrane are achieved with high electrical sealing resistance (over 1 GΩ). In addition, without need for complex fluidic connections, this method allows for an easy operation and further miniaturization of the measuring system.
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Affiliation(s)
- Tianyang Zheng
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China.
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5
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Wadsworth PA, Folorunso O, Nguyen N, Singh AK, D'Amico D, Powell RT, Brunell D, Allen J, Stephan C, Laezza F. High-throughput screening against protein:protein interaction interfaces reveals anti-cancer therapeutics as potent modulators of the voltage-gated Na + channel complex. Sci Rep 2019; 9:16890. [PMID: 31729429 PMCID: PMC6858373 DOI: 10.1038/s41598-019-53110-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/28/2019] [Indexed: 11/09/2022] Open
Abstract
Multiple voltage-gated Na+ (Nav) channelopathies can be ascribed to subtle changes in the Nav macromolecular complex. Fibroblast growth factor 14 (FGF14) is a functionally relevant component of the Nav1.6 channel complex, a causative link to spinocerebellar ataxia 27 (SCA27) and an emerging risk factor for neuropsychiatric disorders. Yet, how this protein:channel complex is regulated in the cell is still poorly understood. To search for key cellular pathways upstream of the FGF14:Nav1.6 complex, we have developed, miniaturized and optimized an in-cell assay in 384-well plates by stably reconstituting the FGF14:Nav1.6 complex using the split-luciferase complementation assay. We then conducted a high-throughput screening (HTS) of 267 FDA-approved compounds targeting known mediators of cellular signaling. Of the 65 hits initially detected, 24 were excluded based on counter-screening and cellular toxicity. Based on target analysis, potency and dose-response relationships, 5 compounds were subsequently repurchased for validation and confirmed as hits. Among those, the tyrosine kinase inhibitor lestaurtinib was highest ranked, exhibiting submicromolar inhibition of FGF14:Nav1.6 assembly. While providing evidence for a robust in-cell HTS platform that can be adapted to search for any channelopathy-associated regulatory proteins, these results lay the potential groundwork for repurposing cancer drugs for neuropsychopharmacology.
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Affiliation(s)
- Paul A Wadsworth
- MD/PhD Combined Degree Program and Biochemistry and Molecular Biology Graduate Program, The University of Texas Medical Branch, Galveston, Texas, 77555, USA.,Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Oluwarotimi Folorunso
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Nghi Nguyen
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - Aditya K Singh
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Daniela D'Amico
- Neuroscience Graduate Program, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Reid T Powell
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - David Brunell
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - John Allen
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Clifford Stephan
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA.
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6
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Manzo G, Ferguson PM, Gustilo VB, Hind CK, Clifford M, Bui TT, Drake AF, Atkinson RA, Sutton JM, Batoni G, Lorenz CD, Phoenix DA, Mason AJ. Minor sequence modifications in temporin B cause drastic changes in antibacterial potency and selectivity by fundamentally altering membrane activity. Sci Rep 2019; 9:1385. [PMID: 30718667 PMCID: PMC6362004 DOI: 10.1038/s41598-018-37630-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/10/2018] [Indexed: 11/08/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a potential source of new molecules to counter the increase in antimicrobial resistant infections but a better understanding of their properties is required to understand their native function and for effective translation as therapeutics. Details of the mechanism of their interaction with the bacterial plasma membrane are desired since damage or penetration of this structure is considered essential for AMPs activity. Relatively modest modifications to AMPs primary sequence can induce substantial changes in potency and/or spectrum of activity but, hitherto, have not been predicted to substantially alter the mechanism of interaction with the bacterial plasma membrane. Here we use a combination of molecular dynamics simulations, circular dichroism, solid-state NMR and patch clamp to investigate the extent to which temporin B and its analogues can be distinguished both in vitro and in silico on the basis of their interactions with model membranes. Enhancing the hydrophobicity of the N-terminus and cationicity of the C-terminus in temporin B improves its membrane activity and potency against both Gram-negative and Gram-positive bacteria. In contrast, enhancing the cationicity of the N-terminus abrogates its ability to trigger channel conductance and renders it ineffective against Gram-positive bacteria while nevertheless enhancing its potency against Escherichia coli. Our findings suggest even closely related AMPs may target the same bacterium with fundamentally differing mechanisms of action.
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Affiliation(s)
- Giorgia Manzo
- Institute of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - Philip M Ferguson
- Institute of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - V Benjamin Gustilo
- Institute of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - Charlotte K Hind
- Technology Development Group, National Infection Service, Public Health England, Salisbury, UK
| | - Melanie Clifford
- Technology Development Group, National Infection Service, Public Health England, Salisbury, UK
| | - Tam T Bui
- Centre for Biomolecular Spectroscopy and Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, London, SE1 1UL, United Kingdom
| | - Alex F Drake
- Centre for Biomolecular Spectroscopy and Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, London, SE1 1UL, United Kingdom
| | - R Andrew Atkinson
- Centre for Biomolecular Spectroscopy and Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, London, SE1 1UL, United Kingdom
| | - J Mark Sutton
- Technology Development Group, National Infection Service, Public Health England, Salisbury, UK
| | - Giovanna Batoni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Christian D Lorenz
- Department of Physics, King's College London, London, WC2R 2LS, United Kingdom
| | - David A Phoenix
- School of Applied Science, London South Bank University, 103 Borough Road, London, SE1 0AA, United Kingdom
| | - A James Mason
- Institute of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom.
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7
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Leung S, Holbrook A, King B, Lu HT, Evans V, Miyamoto N, Mallari C, Harvey S, Davey D, Ho E, Li WW, Parkinson J, Horuk R, Jaroch S, Berger M, Skuballa W, West C, Pulk R, Phillips G, Bryant J, Subramanyam B, Schaefer C, Salamon H, Lyons E, Schilling D, Seidel H, Kraetzschmar J, Snider M, Perez D. Differential Inhibition of Inducible T Cell Cytokine Secretion by Potent Iron Chelators. ACTA ACUST UNITED AC 2016; 10:157-67. [PMID: 15799959 DOI: 10.1177/1087057104272394] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Effector functions and proliferation of T helper (Th) cells are influenced by cytokines in the environment. Th1 cells respond to a synergistic effect of interleukin-12 (IL-12) and interleukin-18 (IL-18) to secrete interferon-gamma (IFN-γ). In contrast, Th2 cells respond to interleukin-4 (IL-4) to secrete IL-4, interleukin-13 (IL-13), interleukin-5 (IL-5), and interleukin-10 (IL-10). The authors were interested in identifying nonpeptide inhibitors of the Th1 response selective for the IL-12/IL-18-mediated secretion of IFN-γ while leaving the IL-4-mediated Th2 cytokine secretion relatively intact. The authors established a screening protocol using human peripheral blood mononuclear cells (PBMCs) and identified the hydrazino anthranilate compound 1 as a potent inhibitor of IL-12/IL-18-mediated IFN-γ secretion from CD3+ cells with an IC50 around 200 nM. The inhibitor was specific because it had virtually no effect on IL-4-mediated IL-13 release from the same population of cells. Further work established that compound 1 was a potent intracellular iron chelator that inhibited both IL-12/IL-18- and IL-4-mediated T cell proliferation. Iron chelation affects multiple cellular pathways in T cells. Thus, the IL-12/IL-18-mediated proliferation and IFN-γ secretion are very sensitive to intracellular iron concentration. However, the IL-4-mediated IL-13 secretion does not correlate with proliferation and is partially resistant to potent iron chelation
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8
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Picones A, Loza-Huerta A, Segura-Chama P, Lara-Figueroa CO. Contribution of Automated Technologies to Ion Channel Drug Discovery. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 104:357-378. [DOI: 10.1016/bs.apcsb.2016.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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9
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Obergrussberger A, Bru ggemann A, Goetze TA, Rapedius M, Haarmann C, Rinke I, Becker N, Oka T, Ohtsuki A, Stengel T, Vogel M, Steindl J, Mueller M, Stiehler J, George M, Fertig N. Automated Patch Clamp Meets High-Throughput Screening: 384 Cells Recorded in Parallel on a Planar Patch Clamp Module. ACTA ACUST UNITED AC 2015; 21:779-793. [DOI: 10.1177/2211068215623209] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Indexed: 11/15/2022]
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10
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Morita T, McClain SP, Batia LM, Pellegrino M, Wilson SR, Kienzler MA, Lyman K, Olsen ASB, Wong JF, Stucky CL, Brem RB, Bautista DM. HTR7 Mediates Serotonergic Acute and Chronic Itch. Neuron 2015; 87:124-38. [PMID: 26074006 DOI: 10.1016/j.neuron.2015.05.044] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 03/31/2015] [Accepted: 05/18/2015] [Indexed: 12/13/2022]
Abstract
Chronic itch is a prevalent and debilitating condition for which few effective therapies are available. We harnessed the natural variation across genetically distinct mouse strains to identify transcripts co-regulated with itch behavior. This survey led to the discovery of the serotonin receptor HTR7 as a key mediator of serotonergic itch. Activation of HTR7 promoted opening of the ion channel TRPA1, which in turn triggered itch behaviors. In addition, acute itch triggered by serotonin or a selective serotonin reuptake inhibitor required both HTR7 and TRPA1. Aberrant serotonin signaling has long been linked to a variety of human chronic itch conditions, including atopic dermatitis. In a mouse model of atopic dermatitis, mice lacking HTR7 or TRPA1 displayed reduced scratching and skin lesion severity. These data highlight a role for HTR7 in acute and chronic itch and suggest that HTR7 antagonists may be useful for treating a variety of pathological itch conditions.
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Affiliation(s)
- Takeshi Morita
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Shannan P McClain
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Lyn M Batia
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Maurizio Pellegrino
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Sarah R Wilson
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael A Kienzler
- Neurobiology Course, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Kyle Lyman
- Neurobiology Course, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | | | - Justin F Wong
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Cheryl L Stucky
- Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Rachel B Brem
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA; Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Diana M Bautista
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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11
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Kikuchi K, Sugiura M, Nishizawa-Harada C, Kimura T. The application of the Escherichia coli giant spheroplast for drug screening with automated planar patch clamp system. ACTA ACUST UNITED AC 2015. [PMID: 28626710 PMCID: PMC5466043 DOI: 10.1016/j.btre.2015.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human Kv2.1 was expressed in the inner membrane of E. coli using prokaryotic codon. Bacterial spheroplasts large enough for the automated patch clamp were prepared by microfluidic chips. Kv2.1 current was recorded from the giant spheroplast by the automated patch clamp. E. coli spheroplasts were used for dose–response assay of potassium channel inhibitors. Our system will become the simple and sensitive drug assay method anyone can use.
Kv2.1, the voltage-gated ion channel, is ubiquitously expressed in variety of tissues and dysfunction of this ion channel is responsible for multiple diseases. Electrophysiological properties of ion channels are so far characterized with eukaryotic cells using the manual patch clamp which requires skilful operators and expensive equipments. In this research, we created a simple and sensitive drug screen method using bacterial giant spheroplasts and the automated patch clamp which does not require special skills. We expressed a eukaryotic voltage-gated ion channel Kv2.1 in Escherichia coli using prokaryotic codon, and prepared giant spheroplasts large enough for the patch clamp. Human Kv2.1 currents were successfully recorded from giant spheroplasts with the automated system, and Kv2.1-expressed E. coli spheroplasts could steadily reacted to the dose–response assay with TEA and 4-AP. Collectively, our results indicate for the first time that the bacterial giant spheroplast can be applied for practical pharmaceutical assay using the automated patch clamp.
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Affiliation(s)
- Kyoko Kikuchi
- Laboratory for Drug Discovery and Glycoscience and Glycotechnology Research Group, Biotechnology Research institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Mika Sugiura
- Laboratory for Drug Discovery and Glycoscience and Glycotechnology Research Group, Biotechnology Research institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Chizuko Nishizawa-Harada
- Laboratory for Drug Discovery and Glycoscience and Glycotechnology Research Group, Biotechnology Research institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Tadashi Kimura
- Laboratory for Drug Discovery and Glycoscience and Glycotechnology Research Group, Biotechnology Research institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
- Corresponding author at: AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan. Tel.: +81 29 861 6667; fax: +81 29 861 3252
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12
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Obergrussberger A, Haarmann C, Rinke I, Becker N, Guinot D, Brueggemann A, Stoelzle‐Feix S, George M, Fertig N. Automated Patch Clamp Analysis of nAChα7 and Na
V
1.7 Channels. ACTA ACUST UNITED AC 2014; 65:11.13.1-48. [DOI: 10.1002/0471141755.ph1113s65] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Liu Q, Wu C, Cai H, Hu N, Zhou J, Wang P. Cell-based biosensors and their application in biomedicine. Chem Rev 2014; 114:6423-61. [PMID: 24905074 DOI: 10.1021/cr2003129] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Qingjun Liu
- Biosensor National Special Laboratory, Key Laboratory of Biomedical Engineering of the Ministry of Education, Department of Biomedical Engineering, Zhejiang University , Hangzhou 310027, China
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14
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HTS assays for developing the molecular pharmacology of ion channels. Curr Opin Pharmacol 2014; 15:91-6. [DOI: 10.1016/j.coph.2014.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 01/24/2014] [Accepted: 01/27/2014] [Indexed: 01/29/2023]
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15
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Surface characteristics and electrical properties of PMMA chips for incubation-type planar-patch-clamp biosensors. Colloids Surf B Biointerfaces 2014; 116:193-200. [PMID: 24480066 DOI: 10.1016/j.colsurfb.2013.12.055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 11/22/2022]
Abstract
Polymethylmethacrylate (PMMA) plates were successfully applied as sensor chips in an incubation-type planar patch clamp (IPPC). Hot embossing both sides formed the PMMA plates, and a focused ion beam realized micropores. The low seal resistance of the IPPC was investigated by analyzing the surface roughness of the chips. Atomic force microscopy (AFM) showed that the chip surface had a roughness of several nanometers due to the molding process. Coating the molded surface with an anti-adhesive compound further increased the surface roughness of the PMMA chip because the anti-adhesive compound itself had a large roughness and in some case, the compound partially peeled off while detaching the mold. Similarly, coating a chip with extracellular matrix (ECM) poly-l-lysine (PLL) also increased the surface roughness. The measured seal resistance of the PMMA chip for an HEK293 cell was in the range of 4-15 MΩ. The low seal resistance was attributed to the sharp-edge structure of the micropore and the surface roughness of the chip. Nevertheless, the whole cell current was successfully recorded from HEK293 cells expressing channel rhodopsin wide receiver (ChRWR) using salt-bridge-type stable Ag/AgCl electrodes. Another advantage of the PMMA sensor chip was the small parasitic capacitance.
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16
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ul Haque A, Chatni MR, Li G, Porterfield DM. Biochips and other microtechnologies for physiomics. Expert Rev Proteomics 2014; 4:553-63. [PMID: 17705712 DOI: 10.1586/14789450.4.4.553] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This paper presents a review of microtechnologies relevant to applications in cellular physiology, including biochips, electrochemical sensors and optrodic sensing techniques. Microelectrodes have been the main tools for measuring cellular electrophysiology, oxygen, nitric oxide, neurotransmitters, pH and various ions. Optical fiber sensing methods, such as indicator-based optrodes, with fluorescence lifetime measurement, are now emerging as viable alternatives to electroanalytical chemistry. These new optrode techniques are possible because of recent advances in the optoelectronics industry and are comparably easier to miniaturize, have faster response times, do not consume the analyte and have lower operational costs. This review serves as a summary and predicts future trends for both electrochemical and optical luminescence lifetime sensing as components in lab-on-a-chip devices for physiological sensing.
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Affiliation(s)
- Aeraj ul Haque
- Purdue University, Department of Agricultural & Biological Engineering, Physiological Sensing Facility, Bindley Bioscience Research Center, West Lafayette, IN 47907, USA.
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17
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Kodandaramaiah SB, Boyden ES, Forest CR. In vivo robotics: the automation of neuroscience and other intact-system biological fields. Ann N Y Acad Sci 2013; 1305:63-71. [PMID: 23841584 PMCID: PMC3797229 DOI: 10.1111/nyas.12171] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Robotic and automation technologies have played a huge role in in vitro biological science, having proved critical for scientific endeavors such as genome sequencing and high-throughput screening. Robotic and automation strategies are beginning to play a greater role in in vivo and in situ sciences, especially when it comes to the difficult in vivo experiments required for understanding the neural mechanisms of behavior and disease. In this perspective, we discuss the prospects for robotics and automation to influence neuroscientific and intact-system biology fields. We discuss how robotic innovations might be created to open up new frontiers in basic and applied neuroscience and present a concrete example with our recent automation of in vivo whole-cell patch clamp electrophysiology of neurons in the living mouse brain.
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Affiliation(s)
- Suhasa B. Kodandaramaiah
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia
- MIT Media Lab, McGovern Institute, Department of Biological Engineering, and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Edward S. Boyden
- MIT Media Lab, McGovern Institute, Department of Biological Engineering, and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Craig R. Forest
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia
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18
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Huys R, Braeken D, Micholt L, Jans D, Stassen A, Collaert N, Loo J, Bartic C, Verstreken K, Eberle W. Micro-sized syringes for single-cell fluidic access integrated on a micro-electrode array CMOS chip. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:7650-3. [PMID: 22256110 DOI: 10.1109/iembs.2011.6091885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Very-large scale integration and micro-machining have enabled the development of novel platforms for advanced and automated examination of cells and tissues in vitro. In this paper, we present a CMOS chip designed in a commercial 0.18 μm technology with integrated micro-syringes combined with micro-nail shaped electrodes and readout electronics. The micro-syringes could be individually addressed by a through-wafer micro-fluidic channel with an inner diameter of 1 μm. We demonstrated the functionality of the micro-fluidic access by diffusion of fluorescent species through the channels. Further, hippocampal neurons were cultured on top of an array of micro-syringes, and focused ion beam-scanning electron microscopy cross-sections revealed protrusion of the cells inside the channels, creating a strong interface between the membrane and the chip surface. This principle demonstrates a first step towards a novel type of automated in vitro platforms, allowing local delivery of substances to cells or advanced planar patch clamping.
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Affiliation(s)
- Roeland Huys
- Imec, Bio-Electronic Systems Group, Kapeldreef 75, 3001 Leuven, Heverlee.
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19
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Shavkunov A, Panova N, Prasai A, Veselenak R, Bourne N, Stoilova-McPhie S, Laezza F. Bioluminescence methodology for the detection of protein-protein interactions within the voltage-gated sodium channel macromolecular complex. Assay Drug Dev Technol 2012; 10:148-60. [PMID: 22364545 DOI: 10.1089/adt.2011.413] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Protein-protein interactions are critical molecular determinants of ion channel function and emerging targets for pharmacological interventions. Yet, current methodologies for the rapid detection of ion channel macromolecular complexes are still lacking. In this study we have adapted a split-luciferase complementation assay (LCA) for detecting the assembly of the voltage-gated Na+ (Nav) channel C-tail and the intracellular fibroblast growth factor 14 (FGF14), a functionally relevant component of the Nav channelosome that controls gating and targeting of Nav channels through direct interaction with the channel C-tail. In the LCA, two complementary N-terminus and C-terminus fragments of the firefly luciferase were fused, respectively, to a chimera of the CD4 transmembrane segment and the C-tail of Nav1.6 channel (CD4-Nav1.6-NLuc) or FGF14 (CLuc-FGF14). Co-expression of CLuc-FGF14 and CD4-Nav1.6-NLuc in live cells led to a robust assembly of the FGF14:Nav1.6 C-tail complex, which was attenuated by introducing single-point mutations at the predicted FGF14:Nav channel interface. To evaluate the dynamic regulation of the FGF14:Nav1.6 C-tail complex by signaling pathways, we investigated the effect of kinase inhibitors on the complex formation. Through a platform of counter screenings, we show that the p38/MAPK inhibitor, PD169316, and the IκB kinase inhibitor, BAY 11-7082, reduce the FGF14:Nav1.6 C-tail complementation, highlighting a potential role of the p38MAPK and the IκB/NFκB pathways in controlling neuronal excitability through protein-protein interactions. We envision the methodology presented here as a new valuable tool to allow functional evaluations of protein-channel complexes toward probe development and drug discovery targeting ion channels implicated in human disorders.
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Affiliation(s)
- Alexander Shavkunov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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20
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Sordel T, Kermarrec F, Sinquin Y, Fonteille I, Labeau M, Sauter-Starace F, Pudda C, de Crécy F, Chatelain F, De Waard M, Arnoult C, Picollet-D’hahan N. The development of high quality seals for silicon patch-clamp chips. Biomaterials 2010; 31:7398-410. [DOI: 10.1016/j.biomaterials.2010.06.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 06/04/2010] [Indexed: 10/19/2022]
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21
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Abstract
For every movement, heartbeat and thought, ion channels need to open and close. It is therefore not surprising that their malfunctioning leads to serious diseases. Currently, only approximately 10% of drugs, with a market value in excess of US$10 billion, act on ion channels. The systematic exploitation of this target class has started, enabled by novel assay technologies and fundamental advances of the structural and mechanistic understanding of channel function. The latter, which was rewarded with the Nobel Prize in 2003, has opened up an avenue for rational drug design. In this review we provide an overview of the current repertoire of screening technologies that has evolved to drive ion channel-targeted drug discovery towards new medicines of the future.
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22
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Weerakoon P, Culurciello E, Klemic KG, Sigworth FJ. An integrated patch-clamp potentiostat with electrode compensation. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2009; 3:117-125. [PMID: 23853203 DOI: 10.1109/tbcas.2008.2005419] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present the first fully integrated implementation of a patch-clamp measurement system with series-access resistance and parasitic capacitive compensation capability. The system was implemented in a 0.5- mum silicon-on-sapphire process and is capable of recording cell membrane currents up to plusmn20 nA, with an rms noise of 5 pA at 10-kHz bandwidth. The system can compensate for the capacitance and resistance of the electrode, up to 20 pF and up to 70% of the series-access resistance, respectively. The die size is 1150 by 700 mum. The power consumption is 300 muW at 3.3 V. The integrated patch-clamp system will be used to fabricate high-throughput planar patch-clamp systems.
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23
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Suzuki H, Takeuchi S. Microtechnologies for membrane protein studies. Anal Bioanal Chem 2008; 391:2695-702. [PMID: 18335213 PMCID: PMC2516541 DOI: 10.1007/s00216-008-1916-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 01/22/2008] [Accepted: 01/23/2008] [Indexed: 11/29/2022]
Abstract
Despite the rapid and enormous progress in biotechnologies, the biochemical analysis of membrane proteins is still a difficult task. The presence of the large hydrophobic region buried in the lipid bilayer membrane (transmembrane domain) makes it difficult to analyze membrane proteins in standard assays developed for water-soluble proteins. To handle membrane proteins, the lipid bilayer membrane may be used as a platform to sustain their functionalities. Relatively slow progress in developing micro total analysis systems (microTAS) for membrane protein analysis directly reflects the difficulty of handling lipid membranes, which is a common problem in bulk measurement technologies. Nonetheless, researchers are continuing to develop efficient and sensitive analytical microsystems for the study of membrane proteins. Here, we review the latest developments, which enable detection of events caused by membrane proteins, such as ion channel current, membrane transport, and receptor/ligand interaction, by utilizing microfabricated structures. High-throughput and highly sensitive detection systems for membrane proteins are now becoming a realistic goal. Although most of these systems are still in the early stages of development, we believe this field will become one of the most important applications of microTAS for pharmaceutical and clinical screenings as well as for basic biochemical research.
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Affiliation(s)
- Hiroaki Suzuki
- Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo, 153-8505 Japan
- Graduate School of Information Science and Technology, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871 Japan
| | - Shoji Takeuchi
- Institute of Industrial Science, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo, 153-8505 Japan
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24
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Suzuki H, Pioufle BL, Takeuhci S. Ninety-six-well planar lipid bilayer chip for ion channel recording Fabricated by hybrid stereolithography. Biomed Microdevices 2008; 11:17-22. [DOI: 10.1007/s10544-008-9205-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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25
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Pamir E, George M, Fertig N, Benoit M. Planar patch-clamp force microscopy on living cells. Ultramicroscopy 2008; 108:552-7. [DOI: 10.1016/j.ultramic.2007.08.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 08/16/2007] [Accepted: 08/29/2007] [Indexed: 11/25/2022]
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26
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Pasquarelli A. Biochips: Technologies and applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2008. [DOI: 10.1016/j.msec.2007.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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Dunlop J, Bowlby M, Peri R, Vasilyev D, Arias R. High-throughput electrophysiology: an emerging paradigm for ion-channel screening and physiology. Nat Rev Drug Discov 2008; 7:358-68. [PMID: 18356919 DOI: 10.1038/nrd2552] [Citation(s) in RCA: 401] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ion channels represent highly attractive targets for drug discovery and are implicated in a diverse range of disorders, in particular in the central nervous and cardiovascular systems. Moreover, assessment of cardiac ion-channel activity of new chemical entities is now an integral component of drug discovery programmes to assess potential for cardiovascular side effects. Despite their attractiveness as drug discovery targets ion channels remain an under-exploited target class, which is in large part due to the labour-intensive and low-throughput nature of patch-clamp electrophysiology. This Review provides an update on the current state-of-the-art for the various automated electrophysiology platforms that are now available and critically evaluates their impact in terms of ion-channel screening, lead optimization and the assessment of cardiac ion-channel safety liability.
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Affiliation(s)
- John Dunlop
- Neuroscience Discovery Research, Wyeth Research, CN-8000, Princeton, New Jersey 08543, USA.
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28
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29
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Mao X, Cao Z, Yin S, Ma Y, Wu Y, Li W. Cloning and characterization of BmK86, a novel K+-channel blocker from scorpion venom. Biochem Biophys Res Commun 2007; 360:728-34. [PMID: 17624312 DOI: 10.1016/j.bbrc.2007.06.108] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 06/18/2007] [Indexed: 10/23/2022]
Abstract
Scorpion venom represents a tremendous hitherto unexplored resource for understanding ion channels. BmK86 is a novel K+ -channel toxin gene isolated from a cDNA library of Mesobuthus martensii Karsch, which encodes a signal peptide of 22 amino acid residues and a mature toxin of 35 residues with three disulfide bridges. The genomic sequence of BmK86 consists of two exons disrupted by an intron of 72 bp. Comparison with the other scorpion toxins BmK86 shows low sequence similarity. The GST-BmK86 fusion protein was successfully expressed in Escherichia coli. The fusion protein was cleaved by enterokinase and the recombinant BmK86 was purified by HPLC. Using whole-cell patch-clamp recording, the recombinant BmK86 was found to inhibit the potassium current of mKv1.3 channel expressed in COS7 cells. These results indicated that BmK86 belongs to a representative member of a novel subfamily of alpha-KTxs. The systematic number assigned to BmK86 is alpha-KTx26.1.
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Affiliation(s)
- Xin Mao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China
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30
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Janshoff A, Steinem C. Transport across artificial membranes–an analytical perspective. Anal Bioanal Chem 2006; 385:433-51. [PMID: 16598461 DOI: 10.1007/s00216-006-0305-9] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2005] [Revised: 12/18/2005] [Accepted: 01/07/2006] [Indexed: 11/25/2022]
Abstract
Biosensors that make use of transport processes across lipid membranes are very rare even though a stimulus, the binding of a single analyte molecule, can enhance the sensor response manifold if the analyte leads to the transport of more than one ion or molecule across the membrane. Prerequisite for a proper function of such membrane based biosensors is the formation of lipid bilayers attached to a support that allow for the insertion of membrane peptides and proteins in a functional manner. In this review, the current state of the art technologies to obtain lipid membranes on various supports are described. Solid supported membranes on transparent and electrically conducting surfaces, lipid bilayers on micromachined apertures and on porous materials are discussed. The focus lies on the applicability of such membranes for the investigation of transport phenomena across lipid bilayers facilitated by membrane embedded peptides, channel proteins and transporters. Carriers and channel forming peptides, which are easy to handle and rather robust, are used frequently to build up membrane based biosensors. However, channel forming proteins and transporters are more difficult to insert functionally and thus, there are yet only few examples that demonstrate the applicability of such systems as biosensor devices.
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Affiliation(s)
- Andreas Janshoff
- Institut für Physikalische Chemie, Johannes-Gutenberg Universität, Jakob-Welder Weg 11, 55128 Mainz, Germany
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31
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Sondermann M, George M, Fertig N, Behrends JC. High-resolution electrophysiology on a chip: Transient dynamics of alamethicin channel formation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:545-51. [PMID: 16696935 DOI: 10.1016/j.bbamem.2006.03.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 03/16/2006] [Accepted: 03/16/2006] [Indexed: 11/23/2022]
Abstract
Microstructured planar substrates have been shown to be suitable for patch clamp recording from both whole cells and isolated patches of membrane, as well as for measurements from planar lipid bilayers. Here, we further explore this technology with respect to high-resolution, low noise single-channel recording. Using solvent-free lipid bilayers from giant unilamellar vesicles obtained by electro-swelling, we recorded channels formed by the peptaibol alamethicin, a well-studied model system for voltage-dependent channels, focusing on the transient dynamics of single-channel formation upon application of a voltage step. With our setup, we were able to distinctly resolve dwell times well below 100 mus and to perform a thorough statistical analysis of alamethicin gating. Our results show good agreement with models that do not rely on the existence of non-conducting preaggregate states. Microstructured apertures in glass substrates appear promising with respect to future experiments on cellular ion channels reconstituted in suspended lipid membranes.
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Affiliation(s)
- Markus Sondermann
- Department of Physiology, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
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32
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Vasilyev DV, Merrill TL, Bowlby MR. Development of a novel automated ion channel recording method using "inside-out" whole-cell membranes. ACTA ACUST UNITED AC 2005; 10:806-13. [PMID: 16234349 DOI: 10.1177/1087057105279481] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Efforts to develop novel methods for recording from ion channels have been receiving increased attention in recent years. In this study, the authors report a unique "inside-out" whole-cell configuration of patch-clamp recording that has been developed. This method entails adding cells into a standard patch pipette and, with positive pressure, obtaining a gigaseal recording from a cell at the inside tip of the electrode. In this configuration, the cell may be moved through the air, first rupturing part of the cellular membrane and enabling bath access to the intracellular side of the membrane, and then into a series of wells containing differing solutions, enabling robotic control of all the steps in an experiment. The robotic system developed here fully automates the electrophysiological experiments, including gigaseal formation, obtaining whole-cell configuration, data acquisition, and drug application. Proof-of-principle experiments consisting of application of intracellularly acting potassium channel blockers to K+ channel cell lines resulted in a very rapid block, as well as block reversal, of the current. This technique allows compound application directly to the intracellular side of ion channels and enables the dissociation of compound in activities due to cellular barrier limitations. This technique should allow for parallel implementation of recording pipettes and the future development of larger array-based screening methods.
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Affiliation(s)
- Dmitry V Vasilyev
- Discovery Neuroscience, Wyeth Research, Princeton, NJ 08543-8000, USA
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33
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Dubin AE, Nasser N, Rohrbacher J, Hermans AN, Marrannes R, Grantham C, Van Rossem K, Cik M, Chaplan SR, Gallacher D, Xu J, Guia A, Byrne NG, Mathes C. Identifying modulators of hERG channel activity using the PatchXpress planar patch clamp. ACTA ACUST UNITED AC 2005; 10:168-81. [PMID: 15799960 DOI: 10.1177/1087057104272295] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The authors used the PatchXpress 7000A system to measure compound activity at the hERG channel using procedures that mimicked the "gold-standard" conventional whole-cell patch clamp. A set of 70 compounds, including hERG antagonists with potencies spanning 3 orders of magnitude, were tested on hERG302-HEK cells using protocols aimed at either identifying compound activity at a single concentration or obtaining compound potency from a cumulative concentration dependence paradigm. After exposure to compounds and subsequent washout of the wells to determine reversibility of the block, blockade by a reference compound served as a quality control. Electrical parameters and voltage dependence were similar to those obtained using a conventional whole-cell patch clamp. Rank order of compound potency was also comparable to that determined by conventional methods. One exception was flunarizine, a particularly lipophilic compound. The PatchXpress accurately identified the activity of 29 moderately potent antagonists, which only weakly displace radiolabeled astemizole and are false negatives in the binding assay. Finally, no false hits were observed from a collection of relatively inactive compounds. High-quality data acquisition by PatchXpress should help accelerate secondary screening for ion channel modulators and the drug discovery process.
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Affiliation(s)
- Adrienne E Dubin
- Pain and Related Disorders, Johnson and Johnson Pharmaceutical Research and Development, San Diego, CA 92121, USA.
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34
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Kirchner C, Liedl T, Kudera S, Pellegrino T, Muñoz Javier A, Gaub HE, Stölzle S, Fertig N, Parak WJ. Cytotoxicity of colloidal CdSe and CdSe/ZnS nanoparticles. NANO LETTERS 2005; 5:331-8. [PMID: 15794621 DOI: 10.1021/nl047996m] [Citation(s) in RCA: 992] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cytotoxicity of CdSe and CdSe/ZnS nanoparticles has been investigated for different surface modifications such as coating with mercaptopropionic acid, silanization, and polymer coating. For all cases, quantitative values for the onset of cytotoxic effects in serum-free culture media are given. These values are correlated with microscope images in which the uptake of the particles by the cells has been investigated. Our data suggest that in addition to the release of toxic Cd(2+) ions from the particles also their surface chemistry, in particular their stability toward aggregation, plays an important role for cytotoxic effects. Additional patch clamp experiments investigate effects of the particles on currents through ion channels.
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35
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Klemic KG, Klemic JF, Sigworth FJ. An air-molding technique for fabricating PDMS planar patch-clamp electrodes. Pflugers Arch 2004; 449:564-72. [PMID: 15578213 DOI: 10.1007/s00424-004-1360-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 09/17/2004] [Accepted: 10/01/2004] [Indexed: 11/25/2022]
Abstract
We present a new technique for fabricating planar patch electrodes in the laboratory. Planar electrodes are micromolded using a micron-sized stream of air to define an aperture in the silicone elastomer, polydimethylsiloxane (PDMS). We have previously demonstrated that planar PDMS electrodes make excellent patch electrodes after surface modification. We demonstrate single-channel measurements of the rSlo channel in Xenopus oocytes and whole-cell measurements in CHO and RBL mammalian cell lines, using planar PDMS electrodes.
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Affiliation(s)
- Kathryn G Klemic
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, 06520, USA
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