1
|
Héliot L, Leray A. Simple phasor-based deep neural network for fluorescence lifetime imaging microscopy. Sci Rep 2021; 11:23858. [PMID: 34903737 PMCID: PMC8668934 DOI: 10.1038/s41598-021-03060-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/23/2021] [Indexed: 12/29/2022] Open
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to probe the molecular environment of fluorophores. The analysis of FLIM images is usually performed with time consuming fitting methods. For accelerating this analysis, sophisticated deep learning architectures based on convolutional neural networks have been developed for restrained lifetime ranges but they require long training time. In this work, we present a simple neural network formed only with fully connected layers able to analyze fluorescence lifetime images. It is based on the reduction of high dimensional fluorescence intensity temporal decays into four parameters which are the phasor coordinates, the mean and amplitude-weighted lifetimes. This network called Phasor-Net has been applied for a time domain FLIM system excited with an 80 MHz laser repetition frequency, with negligible jitter and afterpulsing. Due to the restricted time interval of 12.5 ns, the training range of the lifetimes was limited between 0.2 and 3.0 ns; and the total photon number was lower than 106, as encountered in live cell imaging. From simulated biexponential decays, we demonstrate that Phasor-Net is more precise and less biased than standard fitting methods. We demonstrate also that this simple architecture gives almost comparable performance than those obtained from more sophisticated networks but with a faster training process (15 min instead of 30 min). We finally apply successfully our method to determine biexponential decays parameters for FLIM experiments in living cells expressing EGFP linked to mCherry and fused to a plasma membrane protein.
Collapse
Affiliation(s)
- Laurent Héliot
- PhLAM Laboratoire de Physique Des Lasers, Atomes Et Molécules, UMR 8523, CNRS, University of Lille, Lille, France.
| | - Aymeric Leray
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS, Université de Bourgogne Franche-Comté, Dijon, France.
| |
Collapse
|
2
|
Camborde L, Jauneau A, Brière C, Deslandes L, Dumas B, Gaulin E. Detection of nucleic acid-protein interactions in plant leaves using fluorescence lifetime imaging microscopy. Nat Protoc 2017; 12:1933-1950. [PMID: 28837131 DOI: 10.1038/nprot.2017.076] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA-binding proteins (DNA-BPs) and RNA-binding proteins (RNA-BPs) have critical roles in living cells in all kingdoms of life. Various experimental approaches exist for the study of nucleic acid-protein interactions in vitro and in vivo, but the detection of such interactions at the subcellular level remains challenging. Here we describe how to detect nucleic acid-protein interactions in plant leaves by using a fluorescence resonance energy transfer (FRET) approach coupled to fluorescence lifetime imaging microscopy (FLIM). Proteins of interest (POI) are tagged with a GFP and transiently expressed in plant cells to serve as donor fluorophore. After sample fixation and cell wall permeabilization, leaves are treated with Sytox Orange, a nucleic acid dye that can function as a FRET acceptor. Upon close association of the GFP-tagged POI with Sytox-Orange-stained nucleic acids, a substantial decrease of the GFP lifetime due to FRET between the donor and the acceptor can be monitored. Treatment with RNase before FRET-FLIM measurements allows determination of whether the POI associates with DNA and/or RNA. A step-by-step protocol is provided for sample preparation, data acquisition and analysis. We describe how to calibrate the equipment and include a tutorial explaining the use of the FLIM software. To illustrate our approach, we provide experimental procedures to detect the interaction between plant DNA and two proteins (the AeCRN13 effector from the oomycete Aphanomyces euteiches and the AtWRKY22 defensive transcription factor from Arabidopsis). This protocol allows the detection of protein-nucleic acid interactions in plant cells and can be completed in <2 d.
Collapse
Affiliation(s)
- Laurent Camborde
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Alain Jauneau
- CNRS, Plateforme Imagerie-Microscopie, Fédération de Recherche FR3450, Castanet-Tolosan, France
| | - Christian Brière
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Laurent Deslandes
- LIPM, Université de Toulouse, INRA, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Bernard Dumas
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| | - Elodie Gaulin
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS-Université Toulouse, Castanet-Tolosan, France
| |
Collapse
|
3
|
Botchway SW, Scherer KM, Hook S, Stubbs CD, Weston E, Bisby RH, Parker AW. A series of flexible design adaptations to the Nikon E-C1 and E-C2 confocal microscope systems for UV, multiphoton and FLIM imaging. J Microsc 2015; 258:68-78. [PMID: 25664385 DOI: 10.1111/jmi.12218] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 12/17/2014] [Indexed: 12/16/2022]
Abstract
Multiphoton microscopy is widely employed in the life sciences using extrinsic fluorescence of low- and high-molecular weight labels with excitation and emission spectra in the visible and near infrared regions. For imaging of intrinsic and extrinsic fluorophores with excitation spectra in the ultraviolet region, multiphoton excitation with one- or two-colour lasers avoids the need for ultraviolet-transmitting excitation optics and has advantages in terms of optical penetration in the sample and reduced phototoxicity. Excitation and detection of ultraviolet emission around 300 nm and below in a typical inverted confocal microscope is more difficult and requires the use of expensive quartz optics including the objective. In this technical note we describe the adaptation of a commercial confocal microscope (Nikon, Japan E-C1 or E-C2) for versatile use with Ti-sapphire and OPO laser sources and the addition of a second detection channel that enables detection of ultraviolet fluorescence and increases detection sensitivity in a typical fluorescence lifetime imaging microscopy experiment. Results from some experiments with this setup illustrate the resulting capabilities.
Collapse
Affiliation(s)
- Stanley W Botchway
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Research Complex at Harwell, Harwell Oxford, Didcot, UK
| | | | | | | | | | | | | |
Collapse
|
4
|
Maximum entropy analysis of data simulations and practical aspects of time-resolved fluorescence measurements in the study of molecular interactions. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2013.12.079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
5
|
Implementation of transportation distance for analyzing FLIM and FRET experiments. Bull Math Biol 2014; 76:2596-626. [PMID: 25253276 DOI: 10.1007/s11538-014-0025-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 09/04/2014] [Indexed: 10/24/2022]
Abstract
Analysis of fluorescence lifetime imaging microscopy (FLIM) and Förster resonance energy transfer (FRET) experiments in living cells is usually based on mean lifetimes computations. However, these mean lifetimes can induce misinterpretations. We propose in this work the implementation of the transportation distance for FLIM and FRET experiments in vivo. This non-fitting indicator, which is easy to compute, reflects the similarity between two distributions and can be used for pixels clustering to improve the estimation of the FRET parameters. We study the robustness and the discriminating power of this transportation distance, both theoretically and numerically. In addition, a comparison study with the largely used mean lifetime differences is performed. We finally demonstrate practically the benefits of the transportation distance over the usual mean lifetime differences for both FLIM and FRET experiments in living cells.
Collapse
|
6
|
Leray A, Padilla-Parra S, Roul J, Héliot L, Tramier M. Spatio-Temporal Quantification of FRET in living cells by fast time-domain FLIM: a comparative study of non-fitting methods [corrected]. PLoS One 2013; 8:e69335. [PMID: 23874948 PMCID: PMC3715500 DOI: 10.1371/journal.pone.0069335] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 06/09/2013] [Indexed: 11/30/2022] Open
Abstract
Förster Resonance Energy Transfer (FRET) measured with Fluorescence Lifetime Imaging Microscopy (FLIM) is a powerful technique to investigate spatio-temporal regulation of protein-protein interactions in living cells. When using standard fitting methods to analyze time domain FLIM, the correct estimation of the FRET parameters requires a high number of photons and therefore long acquisition times which are incompatible with the observation of dynamic protein-protein interactions. Recently, non-fitting strategies have been developed for the analysis of FLIM images: the polar plot or "phasor" and the minimal fraction of interacting donor mfD . We propose here a novel non-fitting strategy based on the calculation of moments. We then compare the performance of these three methods when shortening the acquisition time: either by reducing the number of counted photons N or the number of temporal channels Nch , which is particularly adapted for the original fast-FLIM prototype presented in this work that employs the time gated approach. Based on theoretical calculations, Monte Carlo simulations and experimental data, we determine the domain of validity of each method. We thus demonstrate that the polar approach remains accurate for a large range of conditions (low N, Nch or small fractions of interacting donor fD ). The validity domain of the moments method is more restricted (not applicable when fD <0.25 or when Nch = 4) but it is more precise than the polar approach. We also demonstrate that the mfD is robust in all conditions and it is the most precise strategy; although it does not strictly provide the fraction of interacting donor. We show using the fast-FLIM prototype (with an acquisition rate up to 1 Hz) that these non-fitting strategies are very powerful for on-line analysis on a standard computer and thus for quantifying automatically the spatio-temporal activation of Rac-GTPase in living cells by FRET.
Collapse
Affiliation(s)
- Aymeric Leray
- Institut de Recherche Interdisciplinaire, USR 3078 CNRS, Université de Lille-Nord de France, Biophotonique Cellulaire Fonctionnelle, Villeneuve d'Ascq, France.
| | | | | | | | | |
Collapse
|
7
|
Leray A, Spriet C, Trinel D, Usson Y, Héliot L. Generalization of the polar representation in time domain fluorescence lifetime imaging microscopy for biological applications: practical implementation. J Microsc 2013; 248:66-76. [PMID: 22971219 DOI: 10.1111/j.1365-2818.2012.03651.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The polar representation or phasor, which provides a fast and visual indication on the number of exponentials present in the intensity decay of the fluorescence lifetime images is increasingly used in time domain fluorescence lifetime imaging microscopy experiments. The calculations of the polar coordinates in time domain fluorescence lifetime imaging microscopy experiments involve several experimental parameters (e.g. instrumental response function, background, angular frequency, number of temporal channels) whose role has not been exhaustively investigated. Here, we study theoretically, computationally and experimentally the influence of each parameter on the polar calculations and suggest parameter optimization for minimizing errors. We identify several sources of mistakes that may occur in the calculations of the polar coordinates and propose adapted corrections to compensate for them. For instance, we demonstrate that the numerical integration method employed for integrals calculations may induce errors when the number of temporal channels is low. We report theoretical generalized expressions to compensate for these deviations and conserve the semicircle integrity, facilitating the comparison between fluorescence lifetime imaging microscopy images acquired with distinct channels number. These theoretical generalized expressions were finally corroborated with both Monte Carlo simulations and experiments.
Collapse
Affiliation(s)
- A Leray
- Institut de Recherche Interdisciplinaire, USR 3078 CNRS, Université de Lille-Nord de France, BCF, Parc de la Haute Borne, 59650 Villeneuve d'Ascq, France.
| | | | | | | | | |
Collapse
|
8
|
From FRET Imaging to Practical Methodology for Kinase Activity Sensing in Living Cells. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 113:145-216. [DOI: 10.1016/b978-0-12-386932-6.00005-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
9
|
Gidon A, Bardin S, Cinquin B, Boulanger J, Waharte F, Heliot L, Salle H, Hanau D, Kervrann C, Goud B, Salamero J. A Rab11A/Myosin Vb/Rab11-FIP2 Complex Frames Two Late Recycling Steps of Langerin from the ERC to the Plasma Membrane. Traffic 2012; 13:815-33. [DOI: 10.1111/j.1600-0854.2012.01354.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 03/13/2012] [Accepted: 03/15/2012] [Indexed: 01/29/2023]
Affiliation(s)
- Alexandre Gidon
- UMR 144, Molecular Mechanisms of Intracellular Transport Laboratory; CNRS-Institut Curie; 26 rue d'Ulm; 75248; Paris cedex 05; France
| | - Sabine Bardin
- UMR 144, Molecular Mechanisms of Intracellular Transport Laboratory; CNRS-Institut Curie; 26 rue d'Ulm; 75248; Paris cedex 05; France
| | | | - Jerome Boulanger
- Cell and Tissue Imaging Facility, PICT-IBiSA & Nikon Imaging Center; UMR 144 CNRS-Institut Curie; 26 rue d'Ulm; 75248; Paris cedex 05; France
| | - François Waharte
- Cell and Tissue Imaging Facility, PICT-IBiSA & Nikon Imaging Center; UMR 144 CNRS-Institut Curie; 26 rue d'Ulm; 75248; Paris cedex 05; France
| | - Laurent Heliot
- Interdisciplinary Research Institute, Molecular Dynamics and Interaction in Living Cell; 59658; Villeneuve d'Ascq; France
| | - Henri Salle
- INSERM U 725, Biology of Human Dendritic Cells; Strasbourg; France
| | - Daniel Hanau
- INSERM U 725, Biology of Human Dendritic Cells; Strasbourg; France
| | - Charles Kervrann
- INRIA Rennes - Bretagne Atlantique. Team SERPICO; Campus de Beaulieu; 35042; Rennes cedex; France
| | - Bruno Goud
- UMR 144, Molecular Mechanisms of Intracellular Transport Laboratory; CNRS-Institut Curie; 26 rue d'Ulm; 75248; Paris cedex 05; France
| | | |
Collapse
|
10
|
Trinel D, Leray A, Spriet C, Usson Y, Héliot L. Upgrading time domain FLIM using an adaptive Monte Carlo data inflation algorithm. Cytometry A 2011; 79:528-37. [PMID: 21567936 DOI: 10.1002/cyto.a.21054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 02/17/2011] [Accepted: 03/01/2011] [Indexed: 11/09/2022]
Abstract
Fluorescence Lifetime Imaging Microscopy (FLIM) is a powerful technique to investigate the local environment of fluorophores in living cells. To correctly estimate all lifetime parameters, time domain FLIM imaging requires a high number of photons and consequently long laser exposure times. This is an issue because long exposure times are incompatible with the observation of dynamic molecular events and induce cellular stress. To minimize exposure time, we have developed an original approach that statistically inflates the number of collected photons. Our approach, called Adaptive Monte Carlo Data Inflation (AMDI), combines the well-known bootstrap technique with an adaptive Parzen kernel. We here demonstrate using both Monte Carlo simulations and live cells that our robust method accurately estimate fluorescence lifetimes with exposure time reduced up to 50 times for monoexponential decays (corresponding to a minimum of 20 photons/pixel), and 10 times for biexponential decays (corresponding to a minimum of 5,000 photons/pixel), compared to standard fitting method. Thanks to AMDI, in Förster resonance energy transfer experiments, it is possible to estimate all fitting parameters accurately without constraining any parameters. By reducing the commonly used spatial binning factor, our technique also improves the spatial resolution of FLIM images.
Collapse
Affiliation(s)
- Dave Trinel
- Interdisciplinary Research Institute, University of Lille - Nord de France
| | | | | | | | | |
Collapse
|
11
|
Popescu CI, Callens N, Trinel D, Roingeard P, Moradpour D, Descamps V, Duverlie G, Penin F, Héliot L, Rouillé Y, Dubuisson J. NS2 protein of hepatitis C virus interacts with structural and non-structural proteins towards virus assembly. PLoS Pathog 2011; 7:e1001278. [PMID: 21347350 PMCID: PMC3037360 DOI: 10.1371/journal.ppat.1001278] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 01/07/2011] [Indexed: 02/07/2023] Open
Abstract
Growing experimental evidence indicates that, in addition to the physical virion components, the non-structural proteins of hepatitis C virus (HCV) are intimately involved in orchestrating morphogenesis. Since it is dispensable for HCV RNA replication, the non-structural viral protein NS2 is suggested to play a central role in HCV particle assembly. However, despite genetic evidences, we have almost no understanding about NS2 protein-protein interactions and their role in the production of infectious particles. Here, we used co-immunoprecipitation and/or fluorescence resonance energy transfer with fluorescence lifetime imaging microscopy analyses to study the interactions between NS2 and the viroporin p7 and the HCV glycoprotein E2. In addition, we used alanine scanning insertion mutagenesis as well as other mutations in the context of an infectious virus to investigate the functional role of NS2 in HCV assembly. Finally, the subcellular localization of NS2 and several mutants was analyzed by confocal microscopy. Our data demonstrate molecular interactions between NS2 and p7 and E2. Furthermore, we show that, in the context of an infectious virus, NS2 accumulates over time in endoplasmic reticulum-derived dotted structures and colocalizes with both the envelope glycoproteins and components of the replication complex in close proximity to the HCV core protein and lipid droplets, a location that has been shown to be essential for virus assembly. We show that NS2 transmembrane region is crucial for both E2 interaction and subcellular localization. Moreover, specific mutations in core, envelope proteins, p7 and NS5A reported to abolish viral assembly changed the subcellular localization of NS2 protein. Together, these observations indicate that NS2 protein attracts the envelope proteins at the assembly site and it crosstalks with non-structural proteins for virus assembly. Hepatitis C virus (HCV) causes major health problems worldwide. Understanding the major steps of the life cycle of this virus is essential to developing new and more efficient antiviral molecules. Virus assembly is the least understood step of the HCV life cycle. Growing experimental evidence indicates that, in addition to the physical virion components, the HCV non-structural proteins are intimately involved in orchestrating morphogenesis. Since it is dispensable for HCV RNA replication, the non-structural viral protein NS2 is suggested to play a central role in HCV particle assembly. Molecular interactions between NS2 and other HCV proteins were demonstrated. Furthermore, NS2 was shown to accumulate over time in endoplasmic reticulum-derived structures and to colocalize with the viral envelope glycoproteins and viral components of the replication complex in close proximity to the HCV core protein and lipid droplets. Importantly, specific mutations within NS2 that affected HCV infectivity could also alter the subcellular localization of NS2 protein and its interactions, suggesting that this subcellular localization and its interactions are essential for HCV particle assembly. Altogether, these observations indicate that NS2 protein plays an important role in connecting different viral components that are essential for virus assembly.
Collapse
Affiliation(s)
- Costin-Ioan Popescu
- Inserm U1019, CNRS UMR8204, Center for Infection & Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
- Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Nathalie Callens
- Inserm U1019, CNRS UMR8204, Center for Infection & Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
| | - Dave Trinel
- Institute of Interdisciplinary Research, University Lille 1, Villeneuve d'Ascq, France
| | - Philippe Roingeard
- INSERM U966, Université François Rabelais and CHRU de Tours, Tours, France
| | - Darius Moradpour
- Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Véronique Descamps
- Laboratoire de Virologie, Centre Hospitalier Universitaire d'Amiens, Amiens, France
| | - Gilles Duverlie
- Laboratoire de Virologie, Centre Hospitalier Universitaire d'Amiens, Amiens, France
| | - François Penin
- Institut de Biologie et Chimie des Protéines, UMR-5086-CNRS, Université de Lyon, Lyon, France
| | - Laurent Héliot
- Institute of Interdisciplinary Research, University Lille 1, Villeneuve d'Ascq, France
| | - Yves Rouillé
- Inserm U1019, CNRS UMR8204, Center for Infection & Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
| | - Jean Dubuisson
- Inserm U1019, CNRS UMR8204, Center for Infection & Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
- * E-mail:
| |
Collapse
|
12
|
Leray A, Spriet C, Trinel D, Blossey R, Usson Y, Héliot L. Quantitative comparison of polar approach versus fitting method in time domain FLIM image analysis. Cytometry A 2010; 79:149-58. [PMID: 21265008 DOI: 10.1002/cyto.a.20996] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 09/30/2010] [Accepted: 10/21/2010] [Indexed: 11/07/2022]
Abstract
We calculate here analytically the performance of the polar approach (or phasor) in terms of signal-to-noise ratio and F values when performing time-domain Fluorescence Lifetime Imaging Microscopy (FLIM) to determine the minimal number of photons necessary for FLIM measurements (which is directly related to the F value), and compare them to those obtained from a well-known fitting strategy using the Least Square Method (LSM). The importance of the fluorescence background on the lifetime measurement precision is also investigated. We demonstrate here that the LSM does not provide the best estimator of the lifetime parameter for fluorophores exhibiting mono-exponential intensity decays as soon as fluorescence background is superior to 5%. The polar approach enables indeed to determine more precisely the lifetime values for a limited range corresponding to usually encountered fluorescence lifetime values. These theoretical results are corroborated with Monte Carlo simulations. We finally demonstrate experimentally that the polar approach allows distinguishing in living cells two fluorophores undetectable with usual time-domain LSM fitting software.
Collapse
Affiliation(s)
- A Leray
- University of Lille, Biophotonique Cellulaire Fonctionnelle, Parc de la Haute Borne, 59650 Villeneuve d'Ascq, France
| | | | | | | | | | | |
Collapse
|
13
|
Leray A, Riquet FB, Richard E, Spriet C, Trinel D, Héliot L. Optimized protocol of a frequency domain fluorescence lifetime imaging microscope for FRET measurements. Microsc Res Tech 2009; 72:371-9. [DOI: 10.1002/jemt.20665] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
14
|
Hille C, Lahn M, Löhmannsröben HG, Dosche C. Two-photon fluorescence lifetime imaging of intracellular chloride in cockroach salivary glands. Photochem Photobiol Sci 2009; 8:319-27. [DOI: 10.1039/b813797h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
15
|
Liu J, Saw CLL, Olivo M, Sudhaharan T, Ahmed S, Heng PWS, Wohland T. Study of interaction of hypericin and its pharmaceutical preparation by fluorescence techniques. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:014003. [PMID: 19256691 DOI: 10.1117/1.3067726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report the detection of interactions between a photosensitizer, hypericin (HY), and its solvent system prepared with a formulation additive, polyvinylpyrrolidone (PVP), a commonly used pharmaceutical excipient. Fluorescence correlation spectroscopy (FCS) and fluorescence lifetime imaging microscopy (FLIM) were used to study aggregation and binding of HY in the presence of PVP. Digitized fluorescence endoscopic imaging (DFEI) was used to study the effect of the pharmaceutical formulation in the in vivo tumor implanted chick chorioallantoic membrane (CAM) model. The results presented reveal the coordination of HY-PVP binding, HY disaggregation in the presence of PVP, and strengthened HY tumor uptake selectivity. PVP is thus suggested as a potential adjuvant to previously investigated N-methyl pyrrolidone (NMP) in the HY delivery system as well as a replacement for the conventionally used albumin in the HY bladder instillation fluids preparation for clinical use.
Collapse
Affiliation(s)
- Jun Liu
- National University of Singapore, Department of Chemistry, 3 Science Drive 3, Singapore 117543, Singapore
| | | | | | | | | | | | | |
Collapse
|
16
|
Vámosi G, Damjanovich S, Szöllosi J. Dissecting interacting molecular populations by FRET. Cytometry A 2008; 73:681-4. [PMID: 18636568 DOI: 10.1002/cyto.a.20601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- György Vámosi
- Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, University of Debrecen, H-4032 Debrecen, Nagyerdei krt. 98, Hungary
| | | | | |
Collapse
|
17
|
Spriet C, Trinel D, Riquet F, Vandenbunder B, Usson Y, Heliot L. Enhanced FRET contrast in lifetime imaging. Cytometry A 2008; 73:745-53. [PMID: 18496850 DOI: 10.1002/cyto.a.20581] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In combination with two photon excitation, FLIM is currently one of the best techniques to quantitatively study the subcellular localization of protein-protein interactions in living cells. An appropriate analysis procedure is crucial to obtain reliable results. TCSPC is an accurate method to measure FLIM. It is however an indirect process that requires photon decay curve fitting, using an exponential decay equation. Although choosing the number of exponential terms is essential, it is labor-intensive and time consuming. Therefore, a mono-model is usually applied to a whole image. Here we propose an algorithm, named Lichi, allowing pixel by pixel analysis based on the Deltachi(2) value. Lichi was validated using simulated photon decay curves with known lifetimes and proportions. It showed a high robustness for decay curves with more than 10(3) photons. When applied to lifetime images acquired from living cells, it resulted in a more realistic representation of the interaction maps. We developed an easy-to-use procedure for multi-model FLIM analysis, which enables optimized FRET quantification for all interaction texture studies, and is especially suitable to avoid the classical misinterpretation of heterogeneous samples.
Collapse
Affiliation(s)
- Corentin Spriet
- Lille University of Science and Technology, Interdisciplinary Research Institute, CNRS USR 3078, Biophotonic team, 1 rue Prf. Calmette, 59021 Lille cedex, France
| | | | | | | | | | | |
Collapse
|
18
|
Roda A, Guardigli M, Michelini E, Mirasoli M. Nanobioanalytical luminescence: Förster-type energy transfer methods. Anal Bioanal Chem 2008; 393:109-23. [DOI: 10.1007/s00216-008-2435-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/22/2008] [Accepted: 09/23/2008] [Indexed: 12/21/2022]
|
19
|
Thoumine O, Ewers H, Heine M, Groc L, Frischknecht R, Giannone G, Poujol C, Legros P, Lounis B, Cognet L, Choquet D. Probing the dynamics of protein-protein interactions at neuronal contacts by optical imaging. Chem Rev 2008; 108:1565-87. [PMID: 18447398 DOI: 10.1021/cr078204m] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Olivier Thoumine
- CNRS UMR 5091, Institut Magendie, Université Bordeaux 2, 33077 Bordeaux, France.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Szöllosi J, Vereb G. From molecular interactions to tissue organization--diversity of evolving cytometric approaches from a Hungarian perspective. Cytometry A 2008; 73:182-5. [PMID: 18293393 DOI: 10.1002/cyto.a.20542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
21
|
Miserey-Lenkei S, Waharte F, Boulet A, Cuif MH, Tenza D, El Marjou A, Raposo G, Salamero J, Héliot L, Goud B, Monier S. Rab6-interacting protein 1 links Rab6 and Rab11 function. Traffic 2007; 8:1385-403. [PMID: 17725553 DOI: 10.1111/j.1600-0854.2007.00612.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Rab11 and Rab6 guanosine triphosphatases are associated with membranes of the recycling endosomes (REs) and Golgi complex, respectively. Evidence indicates that they sequentially regulate a retrograde transport pathway between these two compartments, suggesting the existence of proteins that must co-ordinate their functions. Here, we report the characterization of two isoforms of a protein, Rab6-interacting protein 1 (R6IP1), originally identified as a Rab6-binding protein. R6IP1 also binds to Rab11A in its GTP-bound conformation. In interphase cells, R6IP1 is targeted to the Golgi in a Rab6-dependent manner but can associate with Rab11-positive compartments when the level of Rab11A is increased within the cells. Fluorescence resonance energy transfer analysis using fluorescence lifetime imaging shows that the overexpression of R6IP1 promotes an interaction between Rab11A and Rab6 in living cells. Accordingly, the REs marked by Rab11 and transferrin receptor are depleted from the cell periphery and accumulate in the pericentriolar area. However, endosomal and Golgi membranes do not appear to fuse with each other. We also show that R6IP1 function is required during metaphase and cytokinesis, two mitotic steps in which a role of Rab6 and Rab11 has been previously documented. We propose that R6IP1 may couple Rab6 and Rab11 function throughout the cell cycle.
Collapse
|
22
|
Li Q, Seeger S. Label-free detection of protein interactions using deep UV fluorescence lifetime microscopy. Anal Biochem 2007; 367:104-10. [PMID: 17553449 DOI: 10.1016/j.ab.2007.04.050] [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] [Received: 02/08/2007] [Revised: 04/25/2007] [Accepted: 04/30/2007] [Indexed: 10/23/2022]
Abstract
We present a label-free detection of protein interaction between beta-galactosidase from Escherichia coli (Ecbeta-Gal) and monoclonal anti-Ecbeta-Gal using deep UV laser-based fluorescence lifetime microscopy. The native fluorescence from intrinsic tryptophan emission was observed after one-photon excitation at 266 nm. Applying the time-correlated single-photon counting (TCSPC) method, we investigated the mean fluorescence lifetime and lifetime distributions from tryptophan residues in Ecbeta-Gal protein, monoclonal anti-Ecbeta-Gal, and corresponding complex. The results demonstrate that deep UV laser-based fluorescence lifetime microscopy is useful for sensitive identification of biological macromolecules interaction using intrinsic fluorescence.
Collapse
Affiliation(s)
- Qiang Li
- Physikalisch-Chemisches Institut der Universität Zurich, CH-8057 Zurich, Switzerland
| | | |
Collapse
|
23
|
Hassan M, Riley J, Chernomordik V, Smith P, Pursley R, Lee SB, Capala J, Amir H G. Fluorescence Lifetime Imaging System for in Vivo Studies. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00019] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this article, a fluorescence lifetime imaging system for small animals is presented. Data were collected by scanning a region of interest with a measurement head, a linear fiber array with fixed separations between a single source fiber and several detection fibers. The goal was to localize tumors and monitor their progression using specific fluorescent markers. We chose a near-infrared contrast agent, Alexa Fluor 750 (Invitrogen Corp., Carlsbad, CA). Preliminary results show that the fluorescence lifetime for this dye was sensitive to the immediate environment of the fluorophore (in particular, pH), making it a promising candidate for reporting physiologic changes around a fluorophore. To quantify the intrinsic lifetime of deeply embedded fluorophores, we performed phantom experiments to investigate the contribution of photon migration effects on observed lifetime by calculating the fluorescence intensity decay time. A previously proposed theoretical model of migration, based on random walk theory, is also substantiated by new experimental data. The developed experimental system has been used for in vivo mouse imaging with Alexa Fluor 750 contrast agent conjugated to tumor-specific antibodies (trastuzumab [Herceptin]). Three-dimensional mapping of the fluorescence lifetime indicates lower lifetime values in superficial breast cancer tumors in mice.
Collapse
Affiliation(s)
- Moinuddin Hassan
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Jason Riley
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Victor Chernomordik
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Paul Smith
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Randall Pursley
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Sang Bong Lee
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Jacek Capala
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Gandjbakhche Amir H
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| |
Collapse
|
24
|
Mies F, Spriet C, Héliot L, Sariban-Sohraby S. Epithelial Na+ channel stimulation by n-3 fatty acids requires proximity to a membrane-bound A-kinase-anchoring protein complexed with protein kinase A and phosphodiesterase. J Biol Chem 2007; 282:18339-18347. [PMID: 17478424 DOI: 10.1074/jbc.m611160200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Essential polyunsatured fatty acids have been shown to modulate enzymes, channels and transporters, to interact with lipid bilayers and to affect metabolic pathways. We have previously shown that eicosapentanoic acid (EPA, C20:5, n-3) activates epithelial sodium channels (ENaCs) in a cAMP-dependent manner involving stimulation of cAMP-dependent protein kinase (PKA). In the present study, we explored further the mechanism of EPA stimulation of ENaC in A6 cells. Fluorescence resonance energy transfer experiments confirmed activation of PKA by EPA. Consistent with our previous studies, EPA had no further stimulatory effect on amiloride-sensitive transepithelial current (INa) in the presence of CPT-cAMP. Thus, we investigated the effect of EPA on cellular pathways which produce cAMP. EPA did not stimulate adenylate cyclase activity or total cellular cAMP accumulation. However, membrane-bound phosphodiesterase activity was inhibited by EPA from 2.46 pmol/mg of protein/min to 1.3 pmol/mg of protein/min. To investigate the potential role of an A-kinase-anchoring protein (AKAP), we used HT31, an inhibitor of the binding between PKA and AKAPs as well as cerulenin, an inhibitor of myristoylation and palmitoylation. Both agents prevented the stimulatory effect of EPA and CPT-cAMP on INa and drastically decreased the amount of PKA in the apical membrane. Colocalization experiments in A6 cells cotransfected with fluorescently labeled ENaC beta subunit and PKA regulatory subunit confirmed the close proximity of the two proteins and the membrane anchorage of PKA. Last, in A6 cells transfected with a dead mutant of Sgk, an enzyme which up-regulates ENaCs, EPA did not stimulate Na+ current. Our results suggest that stimulation of ENaCs by EPA occurs via SGK in membrane-bound compartments containing an AKAP, activated PKA, and a phosphodiesterase.
Collapse
Affiliation(s)
- Frédérique Mies
- Physiology Department, Université Libre de Bruxelles, 808 Route de Lennik, CP604, 1070 Belgium
| | - Corentin Spriet
- Biophotonique Cellulaire Fonctionnelle, Interdisciplinary Research Institute, 1 rue du Prof. Calmette, BP447, 59021 Lille Cedex, France
| | - Laurent Héliot
- Biophotonique Cellulaire Fonctionnelle, Interdisciplinary Research Institute, 1 rue du Prof. Calmette, BP447, 59021 Lille Cedex, France
| | - Sarah Sariban-Sohraby
- Physiology Department, Université Libre de Bruxelles, 808 Route de Lennik, CP604, 1070 Belgium.
| |
Collapse
|
25
|
Spriet C, Trinel D, Waharte F, Deslee D, Vandenbunder B, Barbillat J, Héliot L. Correlated fluorescence lifetime and spectral measurements in living cells. Microsc Res Tech 2007; 70:85-94. [PMID: 17152071 DOI: 10.1002/jemt.20385] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Studies of proteins' interaction in cells by FRET can take benefit from two important photo-physical properties describing fluorescent proteins: fluorescence emission spectrum and fluorescence lifetime. These properties provide specific and complementary information about the tagged proteins and their environment. However, none of them taken individually can completely quantify the involved fluorophore characteristics due to their multiparametric dependency with molecular environment, experimental conditions, and interpretation complexity. A solution to get a better understanding of the biological process implied at the cellular level is to combine the spectral and temporal fluorescence data acquired simultaneously at every cell region under investigation. We present the SLiM-SPRC160, an original temporal/spectral acquisition system for simultaneous lifetime measurements in 16 spectral channels directly attached to the descanned port of a confocal microscope with two-photon excitation. It features improved light throughput, enabling low-level excitation and minimum invasivity in living cells studies. To guarantee a fairly good level of accuracy and reproducibility in the measurements of fluorescence lifetime and spectra on living cells, we propose a rigorous protocol for running experiments with this new equipment that preserves cell viability. The usefulness of SLiM approach for the precise determination of overlapping fluorophores is illustrated with the study of known solutions of rhodamine. Then, we describe reliable FRET experiments in imaging mode realized in living cells using this protocol. We also demonstrate the benefit of localized fluorescence spectrum-lifetime acquisitions for the dynamic study of fluorescent proteins. proteins.
Collapse
Affiliation(s)
- Corentin Spriet
- Biophotonique Cellulaire Fonctionnelle, FRE 2963, Institut de Recherche Interdisciplinaire, 59021 Lille Cedex, France
| | | | | | | | | | | | | |
Collapse
|
26
|
Szöllősi J, Damjanovich S, Nagy P, Vereb G, Mátyus L. Principles of Resonance Energy Transfer. ACTA ACUST UNITED AC 2006; Chapter 1:Unit1.12. [DOI: 10.1002/0471142956.cy0112s38] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | | | - Péter Nagy
- University Medical School of Debrecen Debrecen Hungary
| | - György Vereb
- University Medical School of Debrecen Debrecen Hungary
| | - László Mátyus
- University Medical School of Debrecen Debrecen Hungary
| |
Collapse
|