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Pamungkas KKP, Fureraj I, Assies L, Sakai N, Mercier V, Chen XX, Vauthey E, Matile S. Core-Alkynylated Fluorescent Flippers: Altered Ultrafast Photophysics to Track Thick Membranes. Angew Chem Int Ed Engl 2024; 63:e202406204. [PMID: 38758302 DOI: 10.1002/anie.202406204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/06/2024] [Accepted: 05/16/2024] [Indexed: 05/18/2024]
Abstract
Fluorescent flippers have been introduced as small-molecule probes to image membrane tension in living systems. This study describes the design, synthesis, spectroscopic and imaging properties of flippers that are elongated by one and two alkynes inserted between the push and the pull dithienothiophene domains. The resulting mechanophores combine characteristics of flippers, reporting on physical compression in the ground state, and molecular rotors, reporting on torsional motion in the excited state, to take their photophysics to new level of sophistication. Intensity ratios in broadened excitation bands from differently twisted conformers of core-alkynylated flippers thus report on mechanical compression. Lifetime boosts from ultrafast excited-state planarization and lifetime drops from competitive intersystem crossing into triplet states report on viscosity. In standard lipid bilayer membranes, core-alkynylated flippers are too long for one leaflet and tilt or extend into disordered interleaflet space, which preserves rotor-like torsional disorder and thus weak, blue-shifted fluorescence. Flipper-like planarization occurs only in highly ordered membranes of matching leaflet thickness, where they light up and selectively report on these thick membranes with red-shifted, sharpened excitation maxima, high intensity and long lifetime.
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Affiliation(s)
| | - Ina Fureraj
- Department of Physical Chemistry, University of Geneva, Geneva, Switzerland
| | - Lea Assies
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | | | - Xiao-Xiao Chen
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, Geneva, Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
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Orlikowska-Rzeznik H, Krok E, Domanska M, Setny P, Lągowska A, Chattopadhyay M, Piatkowski L. Dehydration of Lipid Membranes Drives Redistribution of Cholesterol Between Lateral Domains. J Phys Chem Lett 2024; 15:4515-4522. [PMID: 38634827 PMCID: PMC11056968 DOI: 10.1021/acs.jpclett.4c00332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/30/2024] [Accepted: 04/10/2024] [Indexed: 04/19/2024]
Abstract
Cholesterol-rich lipid rafts are found to facilitate membrane fusion, central to processes like viral entry, fertilization, and neurotransmitter release. While the fusion process involves local, transient membrane dehydration, the impact of reduced hydration on cholesterol's structural organization in biological membranes remains unclear. Here, we employ confocal fluorescence microscopy and atomistic molecular dynamics simulations to investigate cholesterol behavior in phase-separated lipid bilayers under controlled hydration. We unveiled that dehydration prompts cholesterol release from raft-like domains into the surrounding fluid phase. Unsaturated phospholipids undergo more significant dehydration-induced structural changes and lose more hydrogen bonds with water than sphingomyelin. The results suggest that cholesterol redistribution is driven by the equalization of biophysical properties between phases and the need to satisfy lipid hydrogen bonds. This underscores the role of cholesterol-phospholipid-water interplay in governing cholesterol affinity for a specific lipid type, providing a new perspective on the regulatory role of cell membrane heterogeneity during membrane fusion.
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Affiliation(s)
- Hanna Orlikowska-Rzeznik
- Faculty of
Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
| | - Emilia Krok
- Faculty of
Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
| | - Maria Domanska
- Biomolecular
Modelling Group, Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Piotr Setny
- Biomolecular
Modelling Group, Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Anna Lągowska
- Faculty of
Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
| | - Madhurima Chattopadhyay
- Faculty of
Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
| | - Lukasz Piatkowski
- Faculty of
Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
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Chen T, Karedla N, Enderlein J. Measuring sub-nanometer undulations at microsecond temporal resolution with metal- and graphene-induced energy transfer spectroscopy. Nat Commun 2024; 15:1789. [PMID: 38413608 PMCID: PMC10899616 DOI: 10.1038/s41467-024-45822-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 02/01/2024] [Indexed: 02/29/2024] Open
Abstract
Out-of-plane fluctuations, also known as stochastic displacements, of biological membranes play a crucial role in regulating many essential life processes within cells and organelles. Despite the availability of various methods for quantifying membrane dynamics, accurately quantifying complex membrane systems with rapid and tiny fluctuations, such as mitochondria, remains a challenge. In this work, we present a methodology that combines metal/graphene-induced energy transfer (MIET/GIET) with fluorescence correlation spectroscopy (FCS) to quantify out-of-plane fluctuations of membranes with simultaneous spatiotemporal resolution of approximately one nanometer and one microsecond. To validate the technique and spatiotemporal resolution, we measure bending undulations of model membranes. Furthermore, we demonstrate the versatility and applicability of MIET/GIET-FCS for studying diverse membrane systems, including the widely studied fluctuating membrane system of human red blood cells, as well as two unexplored membrane systems with tiny fluctuations, a pore-spanning membrane, and mitochondrial inner/outer membranes.
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Affiliation(s)
- Tao Chen
- Third Institute of Physics - Biophysics, Georg August University, Friedrich-Hund-Platz 1, Göttingen, 37077, Germany
| | - Narain Karedla
- The Rosalind Franklin Institute, Harwell Campus, Didcot, OX11 OFA, UK
- Kennedy Institute of Rheumatology, University of Oxford, Roosevelt Drive, Oxford, OX3 7LF, UK
| | - Jörg Enderlein
- Third Institute of Physics - Biophysics, Georg August University, Friedrich-Hund-Platz 1, Göttingen, 37077, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Universitätsmedizin Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany.
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Wang DX, Liu B, Han GM, Li Q, Kong DM, Enderlein J, Chen T. Metal-Induced Energy Transfer (MIET) Imaging of Cell Surface Engineering with Multivalent DNA Nanobrushes. ACS NANO 2024. [PMID: 38231016 PMCID: PMC10883130 DOI: 10.1021/acsnano.3c10162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The spacing between cells has a significant impact on cell-cell interactions, which are critical to the fate and function of both individual cells and multicellular organisms. However, accurately measuring the distance between cell membranes and the variations between different membranes has proven to be a challenging task. In this study, we employ metal-induced energy transfer (MIET) imaging/spectroscopy to determine and track the intermembrane distance and variations with nanometer precision. We have developed a DNA-based molecular adhesive called the DNA nanobrush, which serves as a cellular adhesive for connecting the plasma membranes of different cells. By manipulating the number of base pairs within the DNA nanobrush, we can modify various aspects of membrane-membrane interactions such as adhesive directionality, distance, and forces. We demonstrate that such nanometer-level changes can be detected with MIET imaging/spectroscopy. Moreover, we successfully employed MIET to measure distance variations between a cellular plasma membrane and a model membrane. This experiment not only showcases the effectiveness of MIET as a powerful tool for accurately quantifying membrane-membrane interactions but also validates the potential of DNA nanobrushes as cellular adhesives. This innovative method holds significant implications for advancing the study of multicellular interactions.
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Affiliation(s)
- Dong-Xia Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Center for Cell Responses, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
- III. Institute of Physics - Biophysics, Georg August University, 37077 Göttingen, Germany
| | - Bo Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Center for Cell Responses, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Gui-Mei Han
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Center for Cell Responses, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Qingnan Li
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Center for Cell Responses, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - De-Ming Kong
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Center for Cell Responses, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Jörg Enderlein
- III. Institute of Physics - Biophysics, Georg August University, 37077 Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Universitätsmedizin Göttingen, Robert-Koch-Strasse 40, Göttingen 37075, Germany
| | - Tao Chen
- III. Institute of Physics - Biophysics, Georg August University, 37077 Göttingen, Germany
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