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Kageyama H, Ma T, Sato M, Komiya M, Tadaki D, Hirano-Iwata A. New Aspects of Bilayer Lipid Membranes for the Analysis of Ion Channel Functions. MEMBRANES 2022; 12:membranes12090863. [PMID: 36135882 PMCID: PMC9501126 DOI: 10.3390/membranes12090863] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/26/2022] [Accepted: 08/31/2022] [Indexed: 05/30/2023]
Abstract
The bilayer lipid membrane (BLM) is the main structural component of cell membranes, in which various membrane proteins are embedded. Artificially formed BLMs have been used as a platform in studies of the functions of membrane proteins, including various ion channels. In this review, we summarize recent advances that have been made on artificial BLM systems for the analysis of ion channel functions. We focus on two BLM-based systems, cell-membrane mimicry and four-terminal BLM systems. As a cell-membrane-mimicking system, an efficient screening platform for the evaluation of drug side effects that act on a cell-free synthesized channel has been developed, and its prospects for use in personalized medicine will be discussed. In the four-terminal BLMs, we introduce "lateral voltage" to BLM systems as a novel input to regulate channel activities, in addition to the traditional transmembrane voltages. Such state-of-the-art technologies and new system setups are predicted to pave the way for a variety of applications, in both fundamental physiology and in drug discovery.
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Affiliation(s)
- Hironori Kageyama
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Madoka Sato
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Maki Komiya
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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Andronico LA, Jiang Y, Jung SR, Fujimoto BS, Vojtech L, Chiu DT. Sizing Extracellular Vesicles Using Membrane Dyes and a Single Molecule-Sensitive Flow Analyzer. Anal Chem 2021; 93:5897-5905. [PMID: 33784071 DOI: 10.1021/acs.analchem.1c00253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Extracellular vesicles (EVs) are membranous particles released by most cells in our body, which are involved in many cell-to-cell signaling processes. Given the nanometer sizes and heterogeneity of EVs, highly sensitive methods with single-molecule resolution are fundamental to investigating their biophysical properties. Here, we demonstrate the sizing of EVs using a fluorescence-based flow analyzer with single-molecule sensitivity. Using a dye that selectively partitions into the vesicle's membrane, we show that the fluorescence intensity of a vesicle is proportional to its diameter. We discuss the constraints in sample preparation which are inherent to sizing nanoscale vesicles with a fluorescent membrane dye and propose several guidelines to improve data consistency. After optimizing staining conditions, we were able to measure the size of vesicles in the range ∼35-300 nm, covering the spectrum of EV sizes. Lastly, we developed a method to correct the signal intensity from each vesicle based on its traveling speed inside the microfluidic channel, by operating at a high sampling rate (10 kHz) and measuring the time required for the particle to cross the laser beam. Using this correction, we obtained a threefold greater accuracy in EV sizing, with a precision of ±15-25%.
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Affiliation(s)
- Luca A Andronico
- Department of Chemistry, University of Washington, Seattle 98195, Washington, United States
| | - Yifei Jiang
- Department of Chemistry, University of Washington, Seattle 98195, Washington, United States
| | - Seung-Ryoung Jung
- Department of Chemistry, University of Washington, Seattle 98195, Washington, United States
| | - Bryant S Fujimoto
- Department of Chemistry, University of Washington, Seattle 98195, Washington, United States
| | - Lucia Vojtech
- Department of Obstetrics and Gynecology, University of Washington, Seattle 98195, Washington, United States
| | - Daniel T Chiu
- Department of Chemistry, University of Washington, Seattle 98195, Washington, United States
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Drab E, Sugihara K. Cooperative Function of LL-37 and HNP1 Protects Mammalian Cell Membranes from Lysis. Biophys J 2020; 119:2440-2450. [PMID: 33157121 DOI: 10.1016/j.bpj.2020.10.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/08/2020] [Indexed: 01/10/2023] Open
Abstract
LL-37, cleaved from human cathelicidin, and human neutrophil peptide-1 (HNP1) from the defensin family are antimicrobial peptides that are occasionally co-released from neutrophils, which synergistically kill bacteria. We report that this couple presents another type of cooperativity against host eukaryotic cells, in which they antagonistically minimize cytotoxicity by protecting membranes from lysis. Our results describe the potential of the LL-37/HNP1 cooperativity that switches from membrane-destructive to membrane-protective functions, depending on whether the target is an enemy or a host.
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Affiliation(s)
- Ewa Drab
- Department of Physical Chemistry, University of Geneva, Geneva, Switzerland
| | - Kaori Sugihara
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan; Department of Physical Chemistry, University of Geneva, Geneva, Switzerland.
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Tsemperouli M, Amstad E, Sakai N, Matile S, Sugihara K. Black Lipid Membranes: Challenges in Simultaneous Quantitative Characterization by Electrophysiology and Fluorescence Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8748-8757. [PMID: 31244250 DOI: 10.1021/acs.langmuir.9b00673] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Horizontal black lipid membranes (BLMs) enable optical microscopy to be combined with the electrophysiological measurements for studying ion channels, peptide pores, and ionophores. However, a careful literature review reveals that simultaneous fluorescence and electrical recordings in horizontal BLMs have been rarely reported for an unclear reason, whereas many works employ bright-field microscopy instead of fluorescence microscopy or perform fluorescence imaging and electrical measurements one after another separately without truly exploiting the advantage of the combined setup. In this work, the major causes related to the simultaneous electrical and fluorescence recordings in horizontal BLMs are identified, and several solutions to counteract the issue are also proposed.
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Affiliation(s)
- Maria Tsemperouli
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
| | - Esther Amstad
- Institute of Materials , Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
| | - Naomi Sakai
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
| | - Stefan Matile
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
| | - Kaori Sugihara
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
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