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Wen HY, Hu Y, Duo YY, Zhao L, Wang ZG, Liu SL. Ratiometric Fluorescence Probes for In Situ Imaging of Membrane Tension in Live Cells. Bioconjug Chem 2024; 35:934-943. [PMID: 38935869 DOI: 10.1021/acs.bioconjchem.4c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Membrane tension is an important physical parameter of describing cellular homeostasis, and it is widely used in the study of cellular processes involving membrane deformation and reorganization, such as cell migration, cell spreading, and cell division. Despite the importance of membrane tension, direct measurement remains difficult. In this work, we developed a ratiometric fluorescent probe sensitive to membrane tension by adjusting the carbon chain structure based on polarity-sensitive fluorophores. The probe is sensitive to changes in membrane tension after cells were subjected to physical or chemical stimuli, such as osmotic shock, lipid peroxidation, and mechanical stress. When the polarity of the plasma membrane increases (the green/red ratio decreases) and the membrane tension increases, the relative magnitude of the membrane tension can be quantitatively calculated by fluorescence ratio imaging. Thus, the probe proved to be an efficient and sensitive membrane tension probe.
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Affiliation(s)
- Hai-Yan Wen
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, P. R. China
| | - Yusi Hu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - You-Yang Duo
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - Liang Zhao
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - Zhi-Gang Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, P. R. China
| | - Shu-Lin Liu
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, P. R. China
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, and School of Medicine, Nankai University, Tianjin 300071, P. R. China
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Whiting R, Stanton S, Kucheriava M, Smith AR, Pitts M, Robertson D, Kammer J, Li Z, Fologea D. Hypo-Osmotic Stress and Pore-Forming Toxins Adjust the Lipid Order in Sheep Red Blood Cell Membranes. MEMBRANES 2023; 13:620. [PMID: 37504986 PMCID: PMC10385129 DOI: 10.3390/membranes13070620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 07/29/2023]
Abstract
Lipid ordering in cell membranes has been increasingly recognized as an important factor in establishing and regulating a large variety of biological functions. Multiple investigations into lipid organization focused on assessing ordering from temperature-induced phase transitions, which are often well outside the physiological range. However, particular stresses elicited by environmental factors, such as hypo-osmotic stress or protein insertion into membranes, with respect to changes in lipid status and ordering at constant temperature are insufficiently described. To fill these gaps in our knowledge, we exploited the well-established ability of environmentally sensitive membrane probes to detect intramembrane changes at the molecular level. Our steady state fluorescence spectroscopy experiments focused on assessing changes in optical responses of Laurdan and diphenylhexatriene upon exposure of red blood cells to hypo-osmotic stress and pore-forming toxins at room temperature. We verified our utilized experimental systems by a direct comparison of the results with prior reports on artificial membranes and cholesterol-depleted membranes undergoing temperature changes. The significant changes observed in the lipid order after exposure to hypo-osmotic stress or pore-forming toxins resembled phase transitions of lipids in membranes, which we explained by considering the short-range interactions between membrane components and the hydrophobic mismatch between membrane thickness and inserted proteins. Our results suggest that measurements of optical responses from the membrane probes constitute an appropriate method for assessing the status of lipids and phase transitions in target membranes exposed to mechanical stresses or upon the insertion of transmembrane proteins.
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Affiliation(s)
- Rose Whiting
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| | - Sevio Stanton
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | | | - Aviana R Smith
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Matt Pitts
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| | - Daniel Robertson
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Jacob Kammer
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Department of Family Medicine, Idaho College of Osteopathic Medicine, Meridian, ID 83642, USA
| | - Zhiyu Li
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Daniel Fologea
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
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Abstract
Plasma membrane tension functions as a global physical organizer of cellular activities. Technical limitations of current membrane tension measurement techniques have hampered in-depth investigation of cellular membrane biophysics and the role of plasma membrane tension in regulating cellular processes. Here, we develop an optical membrane tension reporter by repurposing an E. coli mechanosensitive channel via insertion of circularly permuted GFP (cpGFP), which undergoes a large conformational rearrangement associated with channel activation and thus fluorescence intensity changes under increased membrane tension.
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Affiliation(s)
- Yen-Yu Hsu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Agnes M Resto Irizarry
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jianping Fu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109, United States
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Ho PY, Chou TY, Kam C, Huang W, He Z, Ngan AH, Chen S. A dual organelle-targeting mechanosensitive probe. SCIENCE ADVANCES 2023; 9:eabn5390. [PMID: 36630498 PMCID: PMC9833668 DOI: 10.1126/sciadv.abn5390] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Cells are responsive to the mechanical environment, but the methods to detect simultaneously how different organelles react in mechanobiological processes remain largely unexplored. We herein report a dual organelle-targeting fluorescent probe, (E)-1-[3-(diethoxyphosphoryl)propyl]-4-[4-(diethylamino)styryl]pyridin-1-ium bromide (ASP-PE), for mechanical mapping in live cells. ASP-PE is aggregation-induced emission active and is sensitive to the local mechanical environment. It targets the plasma membrane (PM) and intracellular mitochondria in cells by its phosphonate moiety and pyridinium. In this work, through ASP-PE staining, changes of membrane tension in the PM and mitochondria in response to varied osmotic pressure and substrate stiffness are visualized using fluorescence lifetime imaging microscopy. The mechanobiological importance of actin filaments and microtubules in the PM and mitochondria is also investigated using this probe. Computational simulations are applied to study the sensing mechanism of the probe. This study introduces a unique tool for mapping the membrane tension in the PM and mitochondria together, providing us great opportunities to study organelle's interactions in mechanobiology.
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Affiliation(s)
- Po-Yu Ho
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Hong Kong, P. R. China
| | - Tsu Yu Chou
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Hong Kong, P. R. China
| | - Chuen Kam
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Hong Kong, P. R. China
| | - Wenbin Huang
- School of Science, Harbin Institute of Technology, Shenzhen, HIT Campus of University Town, Shenzhen 518055, P. R. China
| | - Zikai He
- School of Science, Harbin Institute of Technology, Shenzhen, HIT Campus of University Town, Shenzhen 518055, P. R. China
| | - Alfonso H. W. Ngan
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Sijie Chen
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Hong Kong, P. R. China
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Zapata-Mercado E, Azarova EV, Hristova K. Effect of reversible osmotic stress on live cell plasma membranes, probed via Laurdan general polarization measurements. Biophys J 2022; 121:2411-2418. [PMID: 35596525 DOI: 10.1016/j.bpj.2022.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/10/2021] [Accepted: 05/16/2022] [Indexed: 11/02/2022] Open
Abstract
Here we seek to gain insight into changes in the plasma membrane of live cells upon the application of osmotic stress using Laurdan, a fluorescent probe that reports on membrane organization, hydration, and dynamics. It is known that the application of osmotic stress to lipid vesicles causes a decrease in Laurdan's generalized polarization (GP), which has been interpreted as an indication of membrane stretching. In cells, we see the opposite effects, as GP increases when the osmolarity of the solution is decreased. This increase in GP is associated with the presence of caveolae, which are known to disassemble and flatten in response to osmotic stress.
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Affiliation(s)
- Elmer Zapata-Mercado
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21218
| | - Evgenia V Azarova
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21218
| | - Kalina Hristova
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21218.
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Identifying and Manipulating Giant Vesicles: Review of Recent Approaches. MICROMACHINES 2022; 13:mi13050644. [PMID: 35630111 PMCID: PMC9144095 DOI: 10.3390/mi13050644] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/13/2022] [Accepted: 04/17/2022] [Indexed: 12/20/2022]
Abstract
Giant vesicles (GVs) are closed bilayer membranes that primarily comprise amphiphiles with diameters of more than 1 μm. Compared with regular vesicles (several tens of nanometers in size), GVs are of greater scientific interest as model cell membranes and protocells because of their structure and size, which are similar to those of biological systems. Biopolymers and nano-/microparticles can be encapsulated in GVs at high concentrations, and their application as artificial cell bodies has piqued interest. It is essential to develop methods for investigating and manipulating the properties of GVs toward engineering applications. In this review, we discuss current improvements in microscopy, micromanipulation, and microfabrication technologies for progress in GV identification and engineering tools. Combined with the advancement of GV preparation technologies, these technological advancements can aid the development of artificial cell systems such as alternative tissues and GV-based chemical signal processing systems.
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Boyd MA, Davis AM, Chambers NR, Tran P, Prindle A, Kamat NP. Vesicle-Based Sensors for Extracellular Potassium Detection. Cell Mol Bioeng 2021; 14:459-469. [PMID: 34777604 DOI: 10.1007/s12195-021-00688-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022] Open
Abstract
Introduction The design of sensors that can detect biological ions in situ remains challenging. While many fluorescent indicators exist that can provide a fast, easy readout, they are often nonspecific, particularly to ions with similar charge states. To address this issue, we developed a vesicle-based sensor that harnesses membrane channels to gate access of potassium (K+) ions to an encapsulated fluorescent indicator. Methods We assembled phospholipid vesicles that incorporated valinomycin, a K+ specific membrane transporter, and that encapsulated benzofuran isophthalate (PBFI), a K+ sensitive dye that nonspecifically fluoresces in the presence of other ions, like sodium (Na+). The specificity, kinetics, and reversibility of encapsulated PBFI fluorescence was determined in a plate reader and fluorimeter. The sensors were then added to E. coli bacterial cultures to evaluate K+ levels in media as a function of cell density. Results Vesicle sensors significantly improved specificity of K+ detection in the presence of a competing monovalent ion, sodium (Na+), and a divalent cation, calcium (Ca2+), relative to controls where the dye was free in solution. The sensor was able to report both increases and decreases in K+ concentration. Finally, we observed our vesicle sensors could detect changes in K+ concentration in bacterial cultures. Conclusion Our data present a new platform for extracellular ion detection that harnesses ion-specific membrane transporters to improve the specificity of ion detection. By changing the membrane transporter and encapsulated sensor, our approach should be broadly useful for designing biological sensors that detect an array of biological analytes in traditionally hard-to-monitor environments. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-021-00688-7.
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Affiliation(s)
- Margrethe A Boyd
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Anna M Davis
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Nora R Chambers
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Peter Tran
- Department of Chemical and Biological Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Arthur Prindle
- Center for Synthetic Biology, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA.,Department of Chemical and Biological Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA.,Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Neha P Kamat
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA.,Center for Synthetic Biology, McCormick School of Engineering, Northwestern University, Evanston, IL 60208 USA
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Plasma Membrane MCC/Eisosome Domains Promote Stress Resistance in Fungi. Microbiol Mol Biol Rev 2020; 84:84/4/e00063-19. [PMID: 32938742 DOI: 10.1128/mmbr.00063-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is growing appreciation that the plasma membrane orchestrates a diverse array of functions by segregating different activities into specialized domains that vary in size, stability, and composition. Studies with the budding yeast Saccharomyces cerevisiae have identified a novel type of plasma membrane domain known as the MCC (membrane compartment of Can1)/eisosomes that correspond to stable furrows in the plasma membrane. MCC/eisosomes maintain proteins at the cell surface, such as nutrient transporters like the Can1 arginine symporter, by protecting them from endocytosis and degradation. Recent studies from several fungal species are now revealing new functional roles for MCC/eisosomes that enable cells to respond to a wide range of stressors, including changes in membrane tension, nutrition, cell wall integrity, oxidation, and copper toxicity. The different MCC/eisosome functions are often intertwined through the roles of these domains in lipid homeostasis, which is important for proper plasma membrane architecture and cell signaling. Therefore, this review will emphasize the emerging models that explain how MCC/eisosomes act as hubs to coordinate cellular responses to stress. The importance of MCC/eisosomes is underscored by their roles in virulence for fungal pathogens of plants, animals, and humans, which also highlights the potential of these domains to act as novel therapeutic targets.
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Cohen AE, Shi Z. Do Cell Membranes Flow Like Honey or Jiggle Like Jello? Bioessays 2019; 42:e1900142. [DOI: 10.1002/bies.201900142] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/31/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Adam E. Cohen
- Departments of Chemistry and Chemical Biology and PhysicsHarvard University Cambridge MA USA
- Howard Hughes Medical Institute Chevy Chase MD USA
| | - Zheng Shi
- Departments of Chemistry and Chemical Biology and PhysicsHarvard University Cambridge MA USA
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Hilburger CE, Jacobs ML, Lewis KR, Peruzzi JA, Kamat NP. Controlling Secretion in Artificial Cells with a Membrane AND Gate. ACS Synth Biol 2019; 8:1224-1230. [PMID: 31051071 DOI: 10.1021/acssynbio.8b00435] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The assembly of channel proteins into vesicle membranes is a useful strategy to control activities of vesicle-based systems. Here, we developed a membrane AND gate that responds to both a fatty acid and a pore-forming channel protein to induce the release of encapsulated cargo. We explored how membrane composition affects the functional assembly of α-hemolysin into phospholipid vesicles as a function of oleic acid content and α-hemolysin concentration. We then showed that we could induce α-hemolysin assembly when we added oleic acid micelles to a specific composition of phospholipid vesicles. Finally, we demonstrated that our membrane AND gate could be coupled to a gene expression system. Our study provides a new method to control the temporal dynamics of vesicle permeability by controlling when the functional assembly of a channel protein into synthetic vesicles occurs. Furthermore, a membrane AND gate that utilizes membrane-associating biomolecules introduces a new way to implement Boolean logic that should complement genetic logic circuits and ultimately enhance the capabilities of artificial cellular systems.
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Diblock copolymers enhance folding of a mechanosensitive membrane protein during cell-free expression. Proc Natl Acad Sci U S A 2019; 116:4031-4036. [PMID: 30760590 PMCID: PMC6410776 DOI: 10.1073/pnas.1814775116] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Membrane protein folding is a critical step that underlies proper cellular function as well as the design of technologies like vesicle-based biosensors and artificial cells. Membrane composition is known to play a role in membrane protein folding; however, the specific mechanical properties of membranes that govern protein folding remain unclear. Using a highly elastic nonnatural amphiphile, we highlight the importance of a membrane mechanical property, membrane elasticity, on the spontaneous insertion and folding of a model α-helical membrane protein. Through this study, we gain a deeper understanding of cellular membrane protein folding and offer a potential approach to improve the production of membrane proteins through optimizing the mechanical properties of synthetic scaffolds present in cell-free reactions. The expression and integration of membrane proteins into vesicle membranes is a critical step in the design of cell-mimetic biosensors, bioreactors, and artificial cells. While membrane proteins have been integrated into a variety of nonnatural membranes, the effects of the chemical and physical properties of these vesicle membranes on protein behavior remain largely unknown. Nonnatural amphiphiles, such as diblock copolymers, provide an interface that can be synthetically controlled to better investigate this relationship. Here, we focus on the initial step in a membrane protein’s life cycle: expression and folding. We observe improvements in both the folding and overall production of a model mechanosensitive channel protein, the mechanosensitive channel of large conductance, during cell-free reactions when vesicles containing diblock copolymers are present. By systematically tuning the membrane composition of vesicles through incorporation of a poly(ethylene oxide)-b-poly(butadiene) diblock copolymer, we show that membrane protein folding and production can be improved over that observed in traditional lipid vesicles. We then reproduce this effect with an alternate membrane-elasticizing molecule, C12E8. Our results suggest that global membrane physical properties, specifically available membrane surface area and the membrane area expansion modulus, significantly influence the folding and yield of a membrane protein. Furthermore, our results set the stage for explorations into how nonnatural membrane amphiphiles can be used to both study and enhance the production of biological membrane proteins.
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