1
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Szomek M, Moesgaard L, Reinholdt P, Haarhøj Hald SB, Petersen D, Krishnan K, Covey DF, Kongsted J, Wüstner D. Membrane organization and intracellular transport of a fluorescent analogue of 27-hydroxycholesterol. Chem Phys Lipids 2020; 233:105004. [PMID: 33137329 DOI: 10.1016/j.chemphyslip.2020.105004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/29/2020] [Accepted: 10/24/2020] [Indexed: 11/30/2022]
Abstract
Oxysterols are cholesterol metabolites with multiple functions in controlling cellular homeostasis. In particular, 27-hydroxycholesterol (27-OH-Chol) has been shown to regulate a variety of physiological functions, but little is known about its uptake, intracellular trafficking, and efflux from cells. This is largely due to a lack of suitable analogs of 27-OH-Chol, which mimic this oxysterol closely. Here, we present the intrinsically fluorescent 27-hydroxy-cholestatrienol (27-OH-CTL), which differs from 27-OH-Chol only by having two additional double bonds in the steroid ring system. Based on molecular dynamics (MD) simulations, we show that 27-OH-CTL possesses almost identical membrane properties compared to 27-OH-Chol. By comparative imaging of 27-OH-CTL and of the cholesterol analogue cholestatrienol (CTL) in living cells, we assess the impact of a single hydroxy group on sterol trafficking. We find that human fibroblasts take up more CTL than 27-OH-CTL, but efflux the oxysterol analogue more efficiently. For both sterols, efflux includes shedding of vesicles from the plasma membrane. Intracellular, 27-OH-CTL accumulates primarily in lipid droplets (LDs), while CTL is mostly found in endosomes and lysosomes. Using fluorescence recovery after photobleaching (FRAP), we find for both sterols a rapidly exchanging pool, which moves orders of magnitude faster than sterol containing vesicles and LDs. In summary, by applying a new fluorescent derivative of 27-OH-Chol we demonstrate that human cells can distinguish sterols based on a single hydroxy group in the side chain, resulting in different transport itineraries, dynamics, and efflux kinetics. Both intrinsically fluorescent cholesterol and oxysterol analogues show rapid non-vesicular transport in human fibroblasts.
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Affiliation(s)
- Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Laust Moesgaard
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Sophia Bell Haarhøj Hald
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Daniel Petersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University, St. Louis, MO 63110, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University, St. Louis, MO 63110, USA
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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2
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Kofod CS, Prioli S, Hornum M, Kongsted J, Reinholdt P. Computational Characterization of Novel Malononitrile Variants of Laurdan with Improved Photophysical Properties for Sensing in Membranes. J Phys Chem B 2020; 124:9526-9534. [PMID: 33074683 DOI: 10.1021/acs.jpcb.0c06011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescent probes are powerful tools for improving our understanding of cellular membranes and other complex biological environments. Using simulations, we gain atomistic and electronic insights into the effectiveness of the probes. In the current work, we have used various computational approaches to comprehensively investigate the properties of the fluorescent probe Laurdan and two Laurdan-like probes: AADAL and ECL. In addition, we propose the development of their corresponding novel malononitrile variants, which are computationally characterized herein. For the candidate probes, electronic structure calculations were used to rationalize their optical properties, including their ability for two-photon activation, and molecular dynamics simulations were used to unravel atomistic details of their functioning within lipid bilayers. While Laurdan, AADAL, and ECL were found to have very similar optical and membrane partitioning profiles, their malononitrile variants were found to show significantly improved optical properties, especially in regard to two-photon cross sections, and they appear to retain the desired membrane characteristics of the parent Laurdan molecule.
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Affiliation(s)
- Cecilie Søderlund Kofod
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Salvatore Prioli
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Mick Hornum
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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3
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Filipe HAL, Moreno MJ, Loura LMS. The Secret Lives of Fluorescent Membrane Probes as Revealed by Molecular Dynamics Simulations. Molecules 2020; 25:E3424. [PMID: 32731549 PMCID: PMC7435664 DOI: 10.3390/molecules25153424] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/23/2020] [Accepted: 07/25/2020] [Indexed: 12/15/2022] Open
Abstract
Fluorescent probes have been employed for more than half a century to study the structure and dynamics of model and biological membranes, using spectroscopic and/or microscopic experimental approaches. While their utilization has led to tremendous progress in our knowledge of membrane biophysics and physiology, in some respects the behavior of bilayer-inserted membrane probes has long remained inscrutable. The location, orientation and interaction of fluorophores with lipid and/or water molecules are often not well known, and they are crucial for understanding what the probe is actually reporting. Moreover, because the probe is an extraneous inclusion, it may perturb the properties of the host membrane system, altering the very properties it is supposed to measure. For these reasons, the need for independent methodologies to assess the behavior of bilayer-inserted fluorescence probes has been recognized for a long time. Because of recent improvements in computational tools, molecular dynamics (MD) simulations have become a popular means of obtaining this important information. The present review addresses MD studies of all major classes of fluorescent membrane probes, focusing in the period between 2011 and 2020, during which such work has undergone a dramatic surge in both the number of studies and the variety of probes and properties accessed.
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Affiliation(s)
- Hugo A. L. Filipe
- Chemistry Department, Coimbra Chemistry Center, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal;
| | - Maria João Moreno
- Coimbra Chemistry Center and CNC—Center for Neuroscience and Cell Biology, Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal;
| | - Luís M. S. Loura
- Coimbra Chemistry Center and CNC—Center for Neuroscience and Cell Biology, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
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4
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Migliore M, Bonvicini A, Tognetti V, Guilhaudis L, Baaden M, Oulyadi H, Joubert L, Ségalas-Milazzo I. Characterization of β-turns by electronic circular dichroism spectroscopy: a coupled molecular dynamics and time-dependent density functional theory computational study. Phys Chem Chem Phys 2020; 22:1611-1623. [PMID: 31894790 DOI: 10.1039/c9cp05776e] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Electronic circular dichroism is one of the most used spectroscopic techniques for peptide and protein structural characterization. However, while valuable experimental spectra exist for α-helix, β-sheet and random coil secondary structures, previous studies showed important discrepancies for β-turns, limiting their use as a reference for structural studies. In this paper, we simulated circular dichroism spectra for the best-characterized β-turns in peptides, namely types I, II, I' and II'. In particular, by combining classical molecular dynamics simulations and state-of-the-art quantum time-dependent density functional theory (with the polarizable embedding multiscale model) computations, two common electronic circular dichroism patterns were found for couples of β-turn types (namely, type I/type II' and type II/type I'), at first for a minimal di-peptide model (Ace-Ala-Ala-NHMe), but also for all sequences tested with non-aromatic residues in the central positions. On the other hand, as expected, aromatic substitution causes important perturbations to the previously found ECD patterns. Finally, by applying suitable approximations, these patterns were subsequently rationalized based on the exciton chirality rule. All these results provide useful predictions and pave the way for a possible experimental characterization of β-turns based on circular dichroism spectroscopy.
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Affiliation(s)
- Mattia Migliore
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
| | - Andrea Bonvicini
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
| | - Vincent Tognetti
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
| | - Laure Guilhaudis
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
| | - Marc Baaden
- Laboratoire de Biochimie Théorique, CNRS, UPR9080, Univ. Paris Diderot, Sorbonne Paris Cité, PSL Research University, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Hassan Oulyadi
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
| | - Laurent Joubert
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
| | - Isabelle Ségalas-Milazzo
- Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesnière, 76821 Mont St Aignan, Cedex, France.
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5
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Filipe HAL, Pokorná Š, Hof M, Amaro M, Loura LMS. Orientation of nitro-group governs the fluorescence lifetime of nitrobenzoxadiazole (NBD)-labeled lipids in lipid bilayers. Phys Chem Chem Phys 2019; 21:1682-1688. [PMID: 30418442 DOI: 10.1039/c8cp06064a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nitrobenzoxadiazole (NBD) labeled lipids are popular fluorescent probes of membrane structure and dynamics, and have been widely used in both model systems and living cells. Irrespective of attachment to the lipid head group or hydrocarbon chains, the NBD fluorophore generally adopts a transverse bilayer location near the host lipid carbonyl/glycerol moieties. Still, considerable variability is observed in the measured fluorescence lifetimes, indicating that overall fluorophore location is not the determinant of NBD fluorescence properties. Combining fluorescence experiments and molecular dynamics simulations, we show that for two almost identical NBD probes, significant differences in fluorophore orientation and fluorescence lifetime are observed. Integrating these findings with literature data, we demonstrate a correlation between NBD orientation and fluorescence lifetime. The latter is longer when the NBD nitro group is predominantly oriented towards the bilayer interior, compared to probes for which it points to the water medium.
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Affiliation(s)
- Hugo A L Filipe
- Coimbra Chemistry Center, University of Coimbra, P-3004-535 Coimbra, Portugal
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6
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Bonvicini A, Reinholdt P, Tognetti V, Joubert L, Wüstner D, Kongsted J. Rational design of novel fluorescent analogues of cholesterol: a “step-by-step” computational study. Phys Chem Chem Phys 2019; 21:15487-15503. [DOI: 10.1039/c9cp01902b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
State-of-the-art quantum chemical and molecular dynamics simulations are used as guidelines in design of novel fluorescent analogues of cholesterol.
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Affiliation(s)
- Andrea Bonvicini
- Normandy Univ. COBRA UMR 6014 & FR 3038
- Université de Rouen
- INSA Rouen
- CNRS
- 76821 Mont Saint Aignan
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy
- University of Southern Denmark
- Odense M
- Denmark
| | - Vincent Tognetti
- Normandy Univ. COBRA UMR 6014 & FR 3038
- Université de Rouen
- INSA Rouen
- CNRS
- 76821 Mont Saint Aignan
| | - Laurent Joubert
- Normandy Univ. COBRA UMR 6014 & FR 3038
- Université de Rouen
- INSA Rouen
- CNRS
- 76821 Mont Saint Aignan
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology
- University of Southern Denmark
- DK-5230 Odense
- Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy
- University of Southern Denmark
- Odense M
- Denmark
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7
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Scheurer M, Herbst MF, Reinholdt P, Olsen JMH, Dreuw A, Kongsted J. Polarizable Embedding Combined with the Algebraic Diagrammatic Construction: Tackling Excited States in Biomolecular Systems. J Chem Theory Comput 2018; 14:4870-4883. [DOI: 10.1021/acs.jctc.8b00576] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Maximilian Scheurer
- Interdisciplinary Center for Scientific Computing, Heidelberg University, D-69120 Heidelberg, Germany
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Michael F. Herbst
- Interdisciplinary Center for Scientific Computing, Heidelberg University, D-69120 Heidelberg, Germany
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Jógvan Magnus Haugaard Olsen
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing, Heidelberg University, D-69120 Heidelberg, Germany
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark
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8
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Structural design of intrinsically fluorescent oxysterols. Chem Phys Lipids 2018; 212:26-34. [DOI: 10.1016/j.chemphyslip.2017.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/22/2017] [Accepted: 12/25/2017] [Indexed: 12/14/2022]
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9
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10
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Nåbo LJ, Olsen JMH, Martínez TJ, Kongsted J. The Quality of the Embedding Potential Is Decisive for Minimal Quantum Region Size in Embedding Calculations: The Case of the Green Fluorescent Protein. J Chem Theory Comput 2017; 13:6230-6236. [DOI: 10.1021/acs.jctc.7b00528] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lina J. Nåbo
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Jógvan Magnus Haugaard Olsen
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Todd J. Martínez
- Department
of Chemistry and PULSE Institute, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94305, United States
| | - Jacob Kongsted
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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