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Prochowska S, Bonarska-Kujawa D, Bobak Ł, Eberhardt M, Niżański W. Fatty acid composition and biophysical characteristics of the cell membrane of feline spermatozoa. Sci Rep 2024; 14:10214. [PMID: 38702489 PMCID: PMC11068737 DOI: 10.1038/s41598-024-61006-5] [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: 02/20/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024] Open
Abstract
Sperm membrane composition and biophysical characteristics play a pivotal role in many physiological processes (i.e. sperm motility, capacitation, acrosome reaction and fusion with the oocyte) as well as in semen processing (e.g. cryopreservation). The aim of this study was to characterize the fatty acid content and biophysical characteristics (anisotropy, generalized polarization) of the cell membrane of domestic cat spermatozoa. Semen was collected from 34 adult male cats by urethral catheterization. After a basic semen evaluation, the fatty acid content of some of the samples (n = 11) was evaluated by gas chromatography. Samples from other individuals (n = 23) were subjected to biophysical analysis: membrane anisotropy (which is inversely proportional to membrane fluidity) and generalized polarization (describing lipid order); both measured by fluorimetry at three temperature points: 38 °C, 25 °C and 5 °C. Spermatozoa from some samples (n = 10) were cryopreserved in TRIS egg yolk-glycerol extender and underwent the same biophysical analysis after thawing. Most fatty acids in feline spermatozoa were saturated (69.76 ± 24.45%), whereas the polyunsaturated fatty acid (PUFA) content was relatively low (6.12 ± 5.80%). Lowering the temperature caused a significant decrease in membrane fluidity and an increase in generalized polarization in fresh spermatozoa, and these effects were even more pronounced following cryopreservation. Anisotropy at 38 °C in fresh samples showed strong positive correlations with viability and motility parameters after thawing. In summary, feline spermatozoa are characterized by a very low PUFA content and a low ratio of unsaturated:saturated fatty acids, which may contribute to low oxidative stress. Cryopreservation alters the structure of the sperm membrane, increasing the fluidity of the hydrophobic portion of the bilayer and the lipid order in the hydrophilic portion. Because lower membrane fluidity in fresh semen was linked with better viability and motility after cryopreservation, this parameter may be considered an important factor in determination of sperm cryoresistance.
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Affiliation(s)
- Sylwia Prochowska
- Department of Reproduction and Clinic of Farm Animals, Wrocław University of Environmental and Life Sciences, 50-366, Wrocław, Poland.
| | - Dorota Bonarska-Kujawa
- Department of Physics and Biophysics, Wrocław University of Environmental and Life Sciences, 50-375, Wrocław, Poland
| | - Łukasz Bobak
- Department of Functional Food Product Development, Wrocław University of Environmental and Life Sciences, 51-630, Wrocław, Poland
| | - Maria Eberhardt
- Department of Reproduction and Clinic of Farm Animals, Wrocław University of Environmental and Life Sciences, 50-366, Wrocław, Poland
| | - Wojciech Niżański
- Department of Reproduction and Clinic of Farm Animals, Wrocław University of Environmental and Life Sciences, 50-366, Wrocław, Poland
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2
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Ramos Docampo MA, Hovorka O, Städler B. Magnetic micromotors crossing lipid membranes. NANOSCALE 2024; 16:2432-2443. [PMID: 38226699 DOI: 10.1039/d3nr05462d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Nano/micromotors are self-propelled particles that show enhanced motion upon being triggered by a stimulus. Their use in nanomedicine has been widely explored, with special focus on imaging or drug delivery. However, a thorough understanding of the requirements for more efficient locomotion is still lacking. In this paper, we assembled magnetically propelled motors of different sizes (i.e., 0.5, 1 and 4 μm) and surface chemistries (positive charge or PEGylated) and assessed their motion in the presence of giant unilamellar lipid vesicles (GUVs) of varying compositions (zwitterionic, negatively charged and saturated lipids). Unexpectedly, the size does not seem to be the dominating characteristics that governs the ability of the motors to cross lipid membranes. Specifically, the 0.5 μm PEGylated motors have very limited ability to cross the lipid membrane of GUVs due to their non-interacting nature compared to their equally sized positively charged counterparts. Furthermore, membranes made of saturated lipids and, in particular, in combination with a weak magnetic field facilitate motors' crossing, regardless of their size. The results were validated by in-house data-driven statistical analysis that employs experimental data to allow for the identification of individual motor motion in the ensemble when meeting the lipid membranes. Altogether, we provide insight into motor locomotion when they interact with a biological barrier considering both the entire ensemble and the individual motors, which has the potential to support considerations of future motor designs.
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Affiliation(s)
- Miguel A Ramos Docampo
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
| | - Ondrej Hovorka
- Faculty of Engineering and Physical Sciences, University of Southampton, SO16 7QF, Southampton, UK
| | - Brigitte Städler
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
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3
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Thakur GCN, Uday A, Jurkiewicz P. FRET-GP - A Local Measure of the Impact of Transmembrane Peptide on Lipids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18390-18402. [PMID: 38048524 DOI: 10.1021/acs.langmuir.3c02505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Reconstitution of a transmembrane protein in model lipid systems allows studying its structure and dynamics in isolation from the complexity of the natural environment. This approach also provides a well-defined environment for studying the interactions of proteins with lipids. In this work, we describe the FRET-GP method, which utilizes Förster resonance energy transfer (FRET) to specifically probe the nanoenvironment of a transmembrane domain. The tryptophan residues flanking this domain act as efficient FRET donors, while Laurdan acts as acceptor. The fluorescence of this solvatochromic probe is quantified using generalized polarization (GP) to report on lipid mobility in the vicinity of the transmembrane domain. We applied FRET-GP to study the transmembrane peptide WALP incorporated in liposomes. We found that the direct excitation of Laurdan to its second singlet state strongly contributes to GP values measured in FRET conditions. Removal of this parasitic contribution was essential for proper determination of GPFRET - the local analogue of classical GP parameter. The presence of WALP significantly increased both parameters but the local effects were considerably stronger (GPFRET ≫ GP). We conclude that WALP restricts lipid movement in its vicinity, inducing lateral inhomogeneity in membrane fluidity. WALP was also found to influence lipid phase transition. Our findings demonstrated that FRET-GP simultaneously provides local and global results, thereby enhancing the depth of information obtained from the measurement. We highlight the simplicity and sensitivity of the method, but also discuss its potential and limitations in studying protein-lipid interactions.
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Affiliation(s)
- Garima C N Thakur
- J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i., Prague 182 00, Czech Republic
| | - Arunima Uday
- J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i., Prague 182 00, Czech Republic
| | - Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i., Prague 182 00, Czech Republic
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4
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Ramirez JM, Calderon-Zavala AC, Balaram A, Heldwein EE. In vitro reconstitution of herpes simplex virus 1 fusion identifies low pH as a fusion co-trigger. mBio 2023; 14:e0208723. [PMID: 37874146 PMCID: PMC10746285 DOI: 10.1128/mbio.02087-23] [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: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 10/25/2023] Open
Abstract
Membrane fusion mediated by herpes simplex virus 1 (HSV-1) is a complex, multi-protein process that is receptor triggered and can occur both at the cell surface and in endosomes. To deconvolute this complexity, we reconstituted HSV-1 fusion with synthetic lipid vesicles in vitro. Using this simplified, controllable system, we discovered that HSV-1 fusion required not only a cognate host receptor but also low pH. On the target membrane side, efficient fusion required cholesterol, negatively charged lipids found in the endosomal membranes, and an optimal balance of lipid order and disorder. On the virion side, the four HSV-1 entry glycoproteins-gB, gD, gH, and gL-were sufficient for fusion. We propose that low pH is a biologically relevant co-trigger for HSV-1 fusion. The dependence of fusion on low pH and endosomal lipids could explain why HSV-1 enters most cell types by endocytosis. We hypothesize that under neutral pH conditions, other, yet undefined, cellular factors may serve as fusion co-triggers. The in vitro fusion system established here can be employed to systematically investigate HSV-1-mediated membrane fusion.IMPORTANCEHSV-1 causes lifelong, incurable infections and diseases ranging from mucocutaneous lesions to fatal encephalitis. Fusion of viral and host membranes is a critical step in HSV-1 infection of target cells that requires multiple factors on both the viral and host sides. Due to this complexity, many fundamental questions remain unanswered, such as the identity of the viral and host factors that are necessary and sufficient for HSV-1-mediated membrane fusion and the nature of the fusion trigger. Here, we developed a simplified in vitro fusion assay to examine the fusion requirements and identified low pH as a co-trigger for virus-mediated fusion in vitro. We hypothesize that low pH has a critical role in cell entry and, potentially, pathogenesis.
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Affiliation(s)
- J. Martin Ramirez
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
- Medical Scientist Training Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ariana C. Calderon-Zavala
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ariane Balaram
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ekaterina E. Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
- Medical Scientist Training Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
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Guzman GG, Farley S, Kyle JE, Bramer LM, Hoeltzl S, van den Dikkenberg J, Holthuis JCM, Tafesse FG. Systematic analysis of the sphingomyelin synthase family in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550547. [PMID: 37546869 PMCID: PMC10402111 DOI: 10.1101/2023.07.25.550547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Sphingomyelin (SM) is a major component of mammalian cell membranes and particularly abundant in the myelin sheath that surrounds nerve fibers. Its production is catalyzed by SM synthases SMS1 and SMS2, which interconvert phosphatidylcholine and ceramide to diacylglycerol and SM in the Golgi and at the plasma membrane, respectively. As the lipids participating in this reaction fulfill both structural and signaling functions, SMS enzymes have considerable potential to influence diverse important cellular processes. The nematode Caenorhabditis elegans is an attractive model for studying both animal development and human disease. The organism contains five SMS homologues but none of these have been characterized in any detail. Here, we carried out the first systematic analysis of SMS family members in C. elegans . Using heterologous expression systems, genetic ablation, metabolic labeling and lipidome analyses, we show that C. elegans harbors at least three distinct SM synthases and one ceramide phosphoethanolamine (CPE) synthase. Moreover, C. elegans SMS family members have partially overlapping but also unique subcellular distributions and together occupy all principal compartments of the secretory pathway. Our findings shed light on crucial aspects of sphingolipid metabolism in a valuable animal model and opens avenues for exploring the role of SM and its metabolic intermediates in organismal development.
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6
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Li Q, Zhu W, Gong S, Jiang S, Feng G. Selective Visualization of Tumor Cell Membranes and Tumors with a Viscosity-Sensitive Plasma Membrane Probe. Anal Chem 2023; 95:7254-7261. [PMID: 37125920 DOI: 10.1021/acs.analchem.3c00220] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cancer is a worldwide health problem. Revealing the changes in the microenvironment after cell carcinogenesis is helpful to understand cancer and develop sensitive methods for cancer diagnosis. We developed herein a viscosity-responsive plasma membrane probe (TPA-S) that was successfully used to probe the viscosity difference between normal and tumor cell plasma membranes for the first time. The probe shows AIE properties with good water solubility, significant near-infrared (NIR) fluorescence responses to viscosity with high sensitivity, and excellent cell membrane location performance. With these features, our experiments showed that TPA-S could selectively visualize cancer cell plasma membranes, revealing that the plasma membrane of tumor cells is more viscous than that of normal cells. In addition, TPA-S was successfully applied to specifically light up tumors. Altogether, this work explored the changes of cell membrane viscosity after canceration, provided a new method for selective visualization of tumor cells, and opened up a new approach for cancer diagnosis.
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Affiliation(s)
- Qianhua Li
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, China
| | - Wenlong Zhu
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, China
| | - Shengyi Gong
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, China
| | - Siyu Jiang
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, China
| | - Guoqiang Feng
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, China
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7
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Huang A, Adler J, Parmryd I. Optimised generalized polarisation analysis of C-laurdan reveals clear order differences between T cell membrane compartments. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184094. [PMID: 36379264 DOI: 10.1016/j.bbamem.2022.184094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/15/2022]
Abstract
Heterogenous packing of plasma membrane lipids is important for cellular processes like signalling, adhesion and sorting of membrane components. Solvatochromic membrane fluorophores that respond to changes from liquid-ordered (lo) phase to liquid-disordered (ld) by red shifts in their emission spectra are often used to assess lipid packing. Their response can be quantified using generalized polarisation (GP) using fluorescence microscopy images from two emission ranges, preferably from a region of interest (ROI) limited to a specific membrane compartment. However, image quality is limited by Poisson noise and convolution by the point spread function of the imaging system. Examining GP-analysis of C-laurdan labelled T cells using the image restoration procedure deconvolution, we demonstrate that deconvolution substantially improves the image resolution by making the plasma membrane clearly discernible and facilitating plasma membrane ROI selection. We conclude that automatic ROI selection has advantages over manual ROI selection when it comes to reproducibility and speed, but reliable GP-measurements can also be obtained by manually demarcated ROIs. We find that deconvolution enhances the difference in GP-values between the plasma and intracellular membranes and demonstrate that moving an intensity defined plasma membrane ROI outwards from the cell further improves this differentiation. By systematically changing the key deconvolution regularization parameter signal to noise, we establish a protocol for deconvolution optimisation applicable to any solvatochromic dye and imaging system. The image processing and ROI selection protocol presented improves both the resolution and precision of GP-measurement and will enable detection of smaller changes in membrane order than is currently achievable.
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Affiliation(s)
- Ainsley Huang
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jeremy Adler
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ingela Parmryd
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
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8
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Horváth Á, Erostyák J, Szőke É. Effect of Lipid Raft Disruptors on Cell Membrane Fluidity Studied by Fluorescence Spectroscopy. Int J Mol Sci 2022; 23:ijms232213729. [PMID: 36430205 PMCID: PMC9697551 DOI: 10.3390/ijms232213729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Lipid rafts are specialized microdomains in cell membranes, rich in cholesterol and sphingolipids, and play an integrative role in several physiological and pathophysiological processes. The integrity of rafts can be disrupted via their cholesterol content-with methyl-β-cyclodextrin (MCD) or with our own carboxamido-steroid compound (C1)-or via their sphingolipid content-with sphingomyelinase (SMase) or with myriocin (Myr). We previously proved by the fluorescent spectroscopy method with LAURDAN that treatment with lipid raft disruptors led to a change in cell membrane polarity. In this study, we focused on the alteration of parameters describing membrane fluidity, such as generalized polarization (GP), characteristic time of the GP values change-Center of Gravity (τCoG)-and rotational mobility (τrot) of LAURDAN molecules. Myr caused a blue shift of the LAURDAN spectrum (higher GP value), while other agents lowered GP values (red shift). MCD decreased the CoG values, while other compounds increased it, so MCD lowered membrane stiffness. In the case of τrot, only Myr lowered the rotation of LAURDAN, while the other compounds increased the speed of τrot, which indicated a more disordered membrane structure. Overall, MCD appeared to increase the fluidity of the membranes, while treatment with the other compounds resulted in decreased fluidity and increased stiffness of the membranes.
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Affiliation(s)
- Ádám Horváth
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti Str. 12, H-7624 Pécs, Hungary
- National Laboratory for Drug Research and Development, Magyar Tudósok Krt. 2, H-1117 Budapest, Hungary
- Department of Pharmacology, Faculty of Pharmacy, University of Pécs, Rókus Str. 2, H-7624 Pécs, Hungary
- Correspondence:
| | - János Erostyák
- János Szentágothai Research Centre and Centre for Neuroscience, University of Pécs, Ifjúság Str. 20, H-7624 Pécs, Hungary
- Department of Experimental Physics, Faculty of Sciences, University of Pécs, Ifjúság Str. 6, H-7624 Pécs, Hungary
| | - Éva Szőke
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti Str. 12, H-7624 Pécs, Hungary
- National Laboratory for Drug Research and Development, Magyar Tudósok Krt. 2, H-1117 Budapest, Hungary
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9
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Spanjers JM, Brodszkij E, Gal N, Skov Pedersen J, Städler B. On the assembly of zwitterionic block copolymers with phospholipids. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Morales-Martínez A, Bertrand B, Hernández-Meza JM, Garduño-Juárez R, Silva-Sanchez J, Munoz-Garay C. Membrane fluidity, composition, and charge affect the activity and selectivity of the AMP ascaphin-8. Biophys J 2022; 121:3034-3048. [PMID: 35842753 PMCID: PMC9463648 DOI: 10.1016/j.bpj.2022.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/28/2022] [Accepted: 07/12/2022] [Indexed: 12/29/2022] Open
Abstract
Ascaphins are cationic antimicrobial peptides that have been shown to have potential in the treatment of infectious diseases caused by multidrug-resistant pathogens (MDR). However, to date, their principal molecular target and mechanism of action are unknown. Results from peptide prediction software and molecular dynamics simulations confirmed that ascaphin-8 is an alpha-helical peptide. For the first time, the peptide was described as membranotrophic using biophysical approaches including calcein liposome leakage, Laurdan general polarization, and dynamic light scattering. Ascaphin-8's activity and selectivity were modulated by rearranging the spatial distribution of lysine (Var-K5), aspartic acid (Var-D4) residues, or substitution of phenylalanine with tyrosine (Var-Y). The parental peptide and its variants presented high affinity toward the bacterial membrane model (≤2 μM), but lost activity in sterol-enriched membranes (mammal and fungal models, with cholesterol and ergosterol, respectively). The peptide-induced pore size was estimated to be >20 nm in the bacterial model, with no difference among peptides. The same pattern was observed in membrane fluidity (general polarization) assays, where all peptides reduced membrane fluidity of the bacterial model but not in the models containing sterols. The peptides also showed high activity toward MDR bacteria. Moreover, peptide sensitivity of the artificial membrane models compared with pathogenic bacterial isolates were in good agreement.
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Affiliation(s)
- Adriana Morales-Martínez
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Cuernavaca, Morelos, México
| | - Brandt Bertrand
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Cuernavaca, Morelos, México
| | - Juan M Hernández-Meza
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Cuernavaca, Morelos, México
| | - Ramón Garduño-Juárez
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Cuernavaca, Morelos, México
| | - Jesús Silva-Sanchez
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - Carlos Munoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Cuernavaca, Morelos, México.
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11
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Sionov RV, Banerjee S, Bogomolov S, Smoum R, Mechoulam R, Steinberg D. Targeting the Achilles’ Heel of Multidrug-Resistant Staphylococcus aureus by the Endocannabinoid Anandamide. Int J Mol Sci 2022; 23:ijms23147798. [PMID: 35887146 PMCID: PMC9319909 DOI: 10.3390/ijms23147798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant Staphylococcus aureus is a major health issue that requires new therapeutic approaches. Accumulating data suggest that it is possible to sensitize these bacteria to antibiotics by combining them with inhibitors targeting efflux pumps, the low-affinity penicillin-binding protein PBP2a, cell wall teichoic acid, or the cell division protein FtsZ. We have previously shown that the endocannabinoid Anandamide (N-arachidonoylethanolamine; AEA) could sensitize drug-resistant S. aureus to a variety of antibiotics, among others, through growth arrest and inhibition of drug efflux. Here, we looked at biochemical alterations caused by AEA. We observed that AEA increased the intracellular drug concentration of a fluorescent penicillin and augmented its binding to membrane proteins with concomitant altered membrane distribution of these proteins. AEA also prevented the secretion of exopolysaccharides (EPS) and reduced the cell wall teichoic acid content, both processes known to require transporter proteins. Notably, AEA was found to inhibit membrane ATPase activity that is necessary for transmembrane transport. AEA did not affect the membrane GTPase activity, and the GTPase cell division protein FtsZ formed the Z-ring of the divisome normally in the presence of AEA. Rather, AEA caused a reduction in murein hydrolase activities involved in daughter cell separation. Altogether, this study shows that AEA affects several biochemical processes that culminate in the sensitization of the drug-resistant bacteria to antibiotics.
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Affiliation(s)
- Ronit Vogt Sionov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
- Correspondence:
| | - Shreya Banerjee
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Sergei Bogomolov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Reem Smoum
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Raphael Mechoulam
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
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12
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Adhyapak P, Dong W, Dasgupta S, Dutta A, Duan M, Kapoor S. Lipid Clustering in Mycobacterial Cell Envelope Layers Governs Spatially Resolved Solvation Dynamics. Chem Asian J 2022; 17:e202200146. [PMID: 35419975 DOI: 10.1002/asia.202200146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/30/2022] [Indexed: 11/06/2022]
Abstract
The mycobacterial cell envelope acts as a multilayered barrier to drugs. However, the role of lipid composition in the properties of different mycobacterial membranes, otherwise dictating their interactions with drugs, is poorly understood. In this study, we found that hydration states, solvation relaxation kinetics, rotational lipid mobility, and lateral lipid diffusion differed between inner and outer mycobacterial membranes. Molecular modeling showed that lipid clustering patterns governed membrane dynamics in the different layers of the cell envelope. By regulating membrane properties, lipid composition and structure modulated water abundance and interactions with lipid head groups. These findings can help deepen our understanding of the physical chemistry underlying membrane structure and function, as well as the interaction of mycobacterial membranes with drugs and host membranes.
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Affiliation(s)
- Pranav Adhyapak
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Wanqian Dong
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Souradip Dasgupta
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Anindya Dutta
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Mojie Duan
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, P. R. China
| | - Shobhna Kapoor
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India.,Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8528, Japan
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Menon AP, Dong W, Lee TH, Aguilar MI, Duan M, Kapoor S. Mutually Exclusive Interactions of Rifabutin with Spatially Distinct Mycobacterial Cell Envelope Membrane Layers Offer Insights into Membrane-Centric Therapy of Infectious Diseases. ACS BIO & MED CHEM AU 2022; 2:395-408. [PMID: 35996474 PMCID: PMC9389580 DOI: 10.1021/acsbiomedchemau.2c00010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anjana P. Menon
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Wanqian Dong
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Tzong-Hsien Lee
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Marie-Isabel Aguilar
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Mojie Duan
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Shobhna Kapoor
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima 739-8528, Japan
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14
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Pokorna S, Ventura AE, Santos TCB, Hof M, Prieto M, Futerman AH, Silva LC. Laurdan in live cell imaging: Effect of acquisition settings, cell culture conditions and data analysis on generalized polarization measurements. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 228:112404. [PMID: 35196617 DOI: 10.1016/j.jphotobiol.2022.112404] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/05/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
Cell function is highly dependent on membrane structure, organization, and fluidity. Therefore, methods to probe the biophysical properties of biological membranes are required. Determination of generalized polarization (GP) values using Laurdan in fluorescence microscopy studies is one of the most widely-used methods to investigate changes in membrane fluidity in vitro and in vivo. In the last couple of decades, there has been a major increase in the number of studies using Laurdan GP, where several different methodological approaches are used. Such differences interfere with data interpretation inasmuch as it is difficult to validate if Laurdan GP variations actually reflect changes in membrane organization or arise from biased experimental approaches. To address this, we evaluated the influence of different methodological details of experimental data acquisition and analysis on Laurdan GP. Our results showed that absolute GP values are highly dependent on several of the parameters analyzed, showing that incorrect data can result from technical and methodological inconsistencies. Considering these differences, we further analyzed the impact of cell variability on GP determination, focusing on basic cell culture conditions, such as cell confluency, number of passages and media composition. Our results show that GP values can report alterations in the biophysical properties of cell membranes caused by cellular adaptation to the culture conditions. In summary, this study provides thorough analysis of the factors that can lead to Laurdan GP variability and suggests approaches to improve data quality, which would generate more precise interpretation and comparison within individual studies and among the literature on Laurdan GP.
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Affiliation(s)
- Sarka Pokorna
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel; J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic.
| | - Ana E Ventura
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel; iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal
| | - Tânia C B Santos
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Manuel Prieto
- iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa, Portugal; Associate Laboratory i4HB-Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Liana C Silva
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
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15
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Levitan I. Evaluating membrane structure by Laurdan imaging: Disruption of lipid packing by oxidized lipids. CURRENT TOPICS IN MEMBRANES 2021; 88:235-256. [PMID: 34862028 DOI: 10.1016/bs.ctm.2021.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Impact of different lipids on membrane structure/lipid order is critical for multiple biological processes. Laurdan microscopy provides a unique tool to assess this property in heterogeneous biological membranes. This review describes the general principles of the approach and its application in model membranes and cells. It also provides an in-depth discussion of the insights obtained using Laurdan microscopy to evaluate the differential effects of cholesterol, oxysterols and oxidized phospholipids on lipid packing of ordered and disordered domains in vascular endothelial cells.
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Affiliation(s)
- Irena Levitan
- Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States.
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16
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De Dios Andres P, Westensee IN, Brodszkij E, Ramos-Docampo MA, Gal N, Städler B. Evaluation of Hybrid Vesicles in an Intestinal Cell Model Based on Structured Paper Chips. Biomacromolecules 2021; 22:3860-3872. [PMID: 34420299 DOI: 10.1021/acs.biomac.1c00686] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell culture-based intestinal models are important to evaluate nanoformulations intended for oral drug delivery. We report the use of a floating structured paper chip as a scaffold for Caco-2 cells and HT29-MTX-E12 cells that are two established cell types used in intestinal cell models. The formation of cell monolayers for both mono- and cocultures in the paper chip are confirmed and the level of formed cell-cell junctions is evaluated. Further, cocultures show first mucus formation between 6-10 days with the mucus becoming more pronounced after 19 days. Hybrid vesicles (HVs) made from phospholipids and the amphiphilic block copolymer poly(cholesteryl methacrylate)-block-poly(2-carboxyethyl acrylate) in different ratios are used as a representative soft nanoparticle to assess their mucopenetration ability in paper chip-based cell cultures. The HV assembly is characterized, and it is illustrated that these HVs cross the mucus layer and are found intracellularly within 3 h when the cells are grown in the paper chips. Taken together, the moist three-dimensional cellulose environment of structured paper chips offers an interesting cell culture-based intestinal model that can be further integrated with fluidic systems or online read-out opportunities.
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Affiliation(s)
- Paula De Dios Andres
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Isabella N Westensee
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Edit Brodszkij
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Miguel A Ramos-Docampo
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Noga Gal
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Brigitte Städler
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
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17
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Influence of liposomes composition on their stability during the nebulization process by vibrating mesh nebulizer. Colloids Surf B Biointerfaces 2021; 204:111793. [PMID: 33932888 DOI: 10.1016/j.colsurfb.2021.111793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/22/2021] [Accepted: 04/24/2021] [Indexed: 11/20/2022]
Abstract
In this study, three different molecules (cholesterol, phosphatidic acid, and polyethylene glycol) were used for the stabilization of liposomes during the nebulization process. The purpose of this article is to answer the question of whether the change in the composition of liposomes affected the parameters of generated aerosol and whether the nebulization process affected observed properties of liposomes. Firstly, liposomes with different composition were prepared and their properties were checked by dynamic and electrophoretic light scattering. The membrane properties were measured by fluorescence spectroscopy - especially generalized polarization (Laurdan) and anisotropy (Diphenylhexatriene). The same characteristic of liposomes was measured after the nebulization by vibrating mesh nebulizer. Cholesterol was capable of liposome stabilization because of increased membrane fluidity. The membrane properties of the outer and inner parts were not influenced by the nebulization process. Electrostatic stabilization was successful for the lowest concentration of phosphatidic acid, but after the nebulization process the hydration of the membrane outer part was changed. Higher amount of PEG needs to be added for successful steric stabilization. The nebulization process of the two lowest concentrations of PEG slightly influenced immobilized water and the rigidity of inner part of the membrane (especially around the phase transition temperature).
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18
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Romano N, Marro M, Marsal M, Loza-Álvarez P, Gomez-Zavaglia A. Fructose derived oligosaccharides prevent lipid membrane destabilization and DNA conformational alterations during vacuum-drying of Lactobacillus delbrueckii subsp. bulgaricus. Food Res Int 2021; 143:110235. [PMID: 33992348 DOI: 10.1016/j.foodres.2021.110235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 11/26/2022]
Abstract
Dehydration of lactic acid bacteria for technological purposes conducts to multilevel damage of bacterial cells. The goal of this work was to determine at which molecular level fructose-oligosaccharides (FOS) and sucrose protect Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 during the vacuum-drying process. To achieve this aim, the cultivability and metabolic activity of vacuum-dried bacteria were firstly determined (plate counting and absorbance kinetics). Then, the membrane integrity and fluidity were assessed using propidium iodide and Laurdan probes (general polarization -GP-), respectively. Finally, bacterial structural alterations were determined using high throughput methods (fluorescence confocal microscopy and Raman spectroscopy coupled to Multivariate Curve Resolution analysis -MCR-). The vacuum-drying process directly affected the microorganism's cultivability and membrane integrity. Non-dehydrated cells and sugar protected bacteria (both with FOS or sucrose) presented high GP values typical from the gel state, as well as phospholipids microdomains laterally organized along the cytoplasmic membrane. On the contrary, bacteria dehydrated without protectants presented low GP values and greater water penetration, associated with membrane destabilization. Raman spectroscopy of vacuum-dried cells revealed DNA conformational changes, B-DNA conformations being associated to non-dehydrated or sugar protected bacteria, and A-DNA conformations being higher in bacteria vacuum-dried without protectants. These results support the role of FOS and sucrose as protective compounds, not only acting at the membrane organizational level but also preventing conformational alterations of intracellular structures, like DNA.
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Affiliation(s)
- Nelson Romano
- Center for Research and Development in Food Cryotechnology (CIDCA, CCT-CONICET La Plata) RA1900, La Plata, Argentina.
| | - Monica Marro
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain.
| | - Maria Marsal
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain
| | - Pablo Loza-Álvarez
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain
| | - Andrea Gomez-Zavaglia
- Center for Research and Development in Food Cryotechnology (CIDCA, CCT-CONICET La Plata) RA1900, La Plata, Argentina
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19
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Havlíková M, Szabová J, Mravcová L, Venerová T, Chang CH, Pekař M, Jugl A, Mravec F. Cholesterol Effect on Membrane Properties of Cationic Ion Pair Amphiphile Vesicles at Different Temperatures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2436-2444. [PMID: 33545006 DOI: 10.1021/acs.langmuir.0c03504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This work is focused on the study of the effect of cholesterol on the properties of vesicular membranes of ionic amphiphilic pairs at different temperatures. The hexadecyltrimethylammonium-dodecyl sulfate ionic amphiphilic pair system with the addition of 10 mol % dioctadecyldimethylammonium chloride was chosen for a detailed study of vesicle properties. A large range of cholesterol concentrations (0-73 mol %) in the temperature range 10-80 °C was studied. Under these conditions, the size distribution, the membrane fluidity, and the surface layer were monitored together with the change in the mobility of water in the surface layer. Obtained quantities were correlated with each other and combined into appropriate graphs. It was found that in stable systems that meet the condition of unimodal size distribution with a PDI value lower than 0.3, temperature has virtually no effect on the size of vesicular systems. On the contrary, when studying the hydration and fluidity of the membrane, significant changes in these parameters were found, which, however, do not affect the short-term stability of these vesicular systems. The presented results thus indicate the possibility of adjusting the composition of the vesicular system in terms of fluidity and membrane hydration while maintaining short-term stability and size distribution.
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Affiliation(s)
- Martina Havlíková
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
| | - Jana Szabová
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
| | - Ludmila Mravcová
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
| | - Tereza Venerová
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
| | - Chien-Hsiang Chang
- Department of Chemical Engineering, National Cheng Kung University, No. 1, University Road, East District, Tainan City 70101, Taiwan
| | - Miloslav Pekař
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
| | - Adam Jugl
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
| | - Filip Mravec
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Brno 612 00, Czech Republic
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20
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Melittin Induces Local Order Changes in Artificial and Biological Membranes as Revealed by Spectral Analysis of Laurdan Fluorescence. Toxins (Basel) 2020; 12:toxins12110705. [PMID: 33171598 PMCID: PMC7695215 DOI: 10.3390/toxins12110705] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/27/2020] [Accepted: 11/05/2020] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a class of molecules widely used in applications on eukaryotic and prokaryotic cells. Independent of the peptide target, all of them need to first pass or interact with the plasma membrane of the cells. In order to have a better image of the peptide action mechanism with respect to the particular features of the membrane it is necessary to better understand the changes induced by AMPs in the membranes. Laurdan, a lipid membrane probe sensitive to polarity changes in the environment, is used in this study for assessing changes induced by melittin, a well-known peptide, both in model and natural lipid membranes. More importantly, we showed that generalized polarization (GP) values are not always efficient or sufficient to properly characterize the changes in the membrane. We proved that a better method to investigate these changes is to use the previously described log-normal deconvolution allowing us to infer other parameters: the difference between the relative areas of elementary peak (ΔSr), and the ratio of elementary peaks areas (Rs). Melittin induced a slight decrease in local membrane fluidity in homogeneous lipid membranes. The addition of cholesterol stabilizes the membrane more in the presence of melittin. An opposite response was observed in the case of heterogeneous lipid membranes in cells, the local order of lipids being diminished. RS proved to be the most sensitive parameter characterizing the local membrane order, allowing us to distinguish among the responses to melittin of both classes of membrane we investigated (liposomes and cellular membranes). Molecular simulation of the melittin pore in homogeneous lipid bilayer suggests that lipids are more closely packed in the proximity of the melittin pore (a smaller area per lipid), supporting the experimental observation.
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21
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Osella S, Knippenberg S. The influence of lipid membranes on fluorescent probes' optical properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183494. [PMID: 33129783 DOI: 10.1016/j.bbamem.2020.183494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Organic fluorophores embedded in lipid bilayers can nowadays be described by a multiscale computational approach. Combining different length and time scales, a full characterization of the probe localization and optical properties led to novel insight into the effect of the environments. SCOPE OF REVIEW Following an introduction on computational advancements, three relevant probes are reviewed that delineate how a multiscale approach can lead to novel insight into the probes' (non) linear optical properties. Attention is paid to the quality of the theoretical description of the optical techniques. MAJOR CONCLUSIONS Computation can assess a priori novel probes' optical properties and guide the analysis and interpretation of experimental data in novel studies. The properties can be used to gain information on the phase and condition of the surrounding biological environment. GENERAL SIGNIFICANCE Computation showed that a canonical view on some of the probes should be revisited and adapted.
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Affiliation(s)
- Silvio Osella
- Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland.
| | - Stefan Knippenberg
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic; Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden; Theoretical Physics, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium.
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22
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The MARCH6-SQLE Axis Controls Endothelial Cholesterol Homeostasis and Angiogenic Sprouting. Cell Rep 2020; 32:107944. [DOI: 10.1016/j.celrep.2020.107944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/23/2020] [Accepted: 07/01/2020] [Indexed: 12/17/2022] Open
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23
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Puff N, Staneva G, Angelova MI, Seigneuret M. Improved Characterization of Raft-Mimicking Phase-Separation Phenomena in Lipid Bilayers Using Laurdan Fluorescence with Log-Normal Multipeak Analysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4347-4356. [PMID: 32233510 DOI: 10.1021/acs.langmuir.0c00412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The study of biomimetic model membrane systems undergoing liquid-ordered (Lo)-liquid-disordered (Ld) phase separation using spectroscopic methods has played an important role in understanding the properties of lipid rafts in plasma membranes. In particular, the membrane-associated fluorescence probe Laurdan has proved to be a very efficient reporter of Lo-Ld phase separation in lipid bilayers using the general polarization (GP) parameter. A limitation of the GP approach is that it monitors only global average packing so that the contribution of each phase remains undetermined. The decomposition of Laurdan emission spectra has been proposed as an additional approach to overcoming this limitation. Here, further developments of this method for the study of Lo-Ld phase separation are described here for Laurdan in sphingomyelin-phosphatidylcholine-cholesterol large unilamellar vesicles. Lipid compositions corresponding to homogeneous Lo or Ld phases as well as undergoing thermally induced Lo-Ld phase separation were investigated. In addition, the occurrence of phase separation was checked by the fluorescence imaging of giant unilamellar vesicles. Decomposition into three log-normal components is used to show that an intermediate energy component is specifically associated with the occurrence of the Lo phase, with a small contribution from this component occurring above the phase-separation temperature being attributable to phase fluctuations. The ratio RX of the relative area of this intermediate-energy peak to that of the low-energy peak is shown to provide a straightforward index of Lo-Ld phase separation as a function of temperature, which is occasionally more sensitive than GP. It is also shown that RX can be used in conjunction with GP to gain further insight into Lo-Ld, the phase-separation processes. This latter feature is illustrated by the influence of the alcohol butanol on the Lo-Ld phase separation in sphingomyelin-phosphatidylcholine-cholesterol bilayers by showing that the effect of the alcohol occurs specifically at the onset of the phase separation, indicating a line tension mechanism. It is proposed that the three components of log-normal decomposition approaching Laurdan emission spectra provide a useful improvement for characterizing Lo-Ld phase-separation phenomena.
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Affiliation(s)
- Nicolas Puff
- Sorbonne Université, Faculté des Sciences et Ingénierie, UFR 925 Physique, Paris F-75005, France
- Université Paris Diderot - Paris 7, Université de Paris, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Paris F-75013, France
| | - Galya Staneva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Miglena I Angelova
- Sorbonne Université, Faculté des Sciences et Ingénierie, UFR 925 Physique, Paris F-75005, France
- Université Paris Diderot - Paris 7, Université de Paris, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Paris F-75013, France
| | - Michel Seigneuret
- Université Paris Diderot - Paris 7, Université de Paris, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Paris F-75013, France
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24
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Ferrihydrite nanoparticles interaction with model lipid membranes. Chem Phys Lipids 2019; 226:104851. [PMID: 31836519 DOI: 10.1016/j.chemphyslip.2019.104851] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/25/2019] [Accepted: 12/04/2019] [Indexed: 11/24/2022]
Abstract
In recent years was observed an increased interest towards the use of metal nanoparticles for various biomedical applications, such as therapeutics, delivery systems or imaging. As biological membranes are the first structures with which the nanoparticles interact, it is necessary to understand better the mechanisms governing these interactions. In the present paper we aim to characterize the effect of three different ferrihydrite nanoparticles (simple or doped with cooper or cobalt) on the fluidity of model lipid membranes. First we evaluated the physicochemical properties of the nanoparticles: size and composition. Secondly, their effect on lipid membranes was also evaluated using Laurdan, TMA-DPH and DPH fluorescence. Our results can help better understand the mechanisms involved in nanoparticles and membrane interactions.
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25
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Leung SSW, Brewer J, Bagatolli LA, Thewalt JL. Measuring molecular order for lipid membrane phase studies: Linear relationship between Laurdan generalized polarization and deuterium NMR order parameter. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183053. [DOI: 10.1016/j.bbamem.2019.183053] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/27/2019] [Accepted: 08/21/2019] [Indexed: 01/03/2023]
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26
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Osella S, Knippenberg S. Laurdan as a Molecular Rotor in Biological Environments. ACS APPLIED BIO MATERIALS 2019; 2:5769-5778. [DOI: 10.1021/acsabm.9b00789] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Stefan Knippenberg
- RCPTM, Department of Physical Chemistry, Fac. Sciences, Palacký University, 771 46 Olomouc, Czech Republic
- Theoretical Physics, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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27
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Fujikawa K, Nomura K, Nishiyama KI, Shimamoto K. Novel Glycolipid Involved in Membrane Protein Integration: Structure and Mode of Action. J SYN ORG CHEM JPN 2019. [DOI: 10.5059/yukigoseikyokaishi.77.1096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences
| | - Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences
| | - Ken-ichi Nishiyama
- Department of Biological Chemistry, Faculty of Agriculture, Iwate University
| | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences
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28
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Calori IR, Pazin WM, Brunaldi K, Pellosi DS, Caetano W, Tedesco AC, Hioka N. Laurdan as fluorescent probe to determinate the critical micelle temperature of polymers from Pluronic®-coated fluid phase liposomes. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111562] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Li G, Kakuda S, Suresh P, Canals D, Salamone S, London E. Replacing plasma membrane outer leaflet lipids with exogenous lipid without damaging membrane integrity. PLoS One 2019; 14:e0223572. [PMID: 31589646 PMCID: PMC6779269 DOI: 10.1371/journal.pone.0223572] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 09/20/2019] [Indexed: 12/24/2022] Open
Abstract
We recently introduced a MαCD-based method to efficiently replace virtually the entire population of plasma membrane outer leaflet phospholipids and sphingolipids of cultured mammalian cells with exogenous lipids (Li et al, (2016) Proc. Natl. Acad. Sci USA 113:14025–14030). Here, we show if the lipid-to- MαCD ratio is too high or low, cells can round up and develop membrane leakiness. We found that this cell damage can be reversed/prevented if cells are allowed to recover from the exchange step by incubation in complete growth medium. After exchange and transfer to complete growth medium cell growth was similar to that of untreated cells. In some cases, cell damage was also prevented by carrying out exchange at close to room temperature (rather than at 37°C). Exchange with lipids that do (sphingomyelin) or do not (unsaturated phosphatidylcholine) support a high level of membrane order in lipid vesicles had the analogous effect on plasma membrane order, confirming exogenous lipid localization in the plasma membrane. Importantly, changes in lipid composition and plasma membrane properties after exchange and recovery persisted for several hours. Thus, it should be possible to use lipid exchange to investigate the effect of plasma membrane lipid composition upon several aspects of membrane structure and function.
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Affiliation(s)
- Guangtao Li
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
| | - Shinako Kakuda
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
| | - Pavana Suresh
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
| | - Daniel Canals
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Silvia Salamone
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, United States of America
| | - Erwin London
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
- * E-mail:
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Ober K, Volz-Rakebrand P, Stellmacher J, Brodwolf R, Licha K, Haag R, Alexiev U. Expanding the Scope of Reporting Nanoparticles: Sensing of Lipid Phase Transitions and Nanoviscosities in Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11422-11434. [PMID: 31378067 DOI: 10.1021/acs.langmuir.9b01372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Biological membrane fluidity and thus the local viscosity in lipid membranes are of vital importance for many life processes and implicated in various diseases. Here, we introduce a novel viscosity sensor design for lipid membranes based on a reporting nanoparticle, a sulfated dendritic polyglycerol (dPGS), conjugated to a fluorescent molecular rotor, indocarbocyanine (ICC). We show that dPGS-ICC provides high affinity to lipid bilayers, enabling viscosity sensing in the lipid tail region. The systematic characterization of viscosity- and temperature-dependent photoisomerization properties of ICC and dPGS-ICC allowed us to determine membrane viscosities in different model systems and in living cells using fluorescence lifetime imaging (FLIM). dPGS-ICC distinguishes between ordered lipids and the onset of membrane defects in small unilamellar single lipid vesicles and is highly sensitive in the fluid phase to small changes in viscosity introduced by cholesterol. In microscopy-based viscosity measurements of large multilamellar vesicles, we observed an order of magnitude more viscous environments by dPGS-ICC, lending support to the hypothesis of heterogeneous nanoviscosity environments even in single lipid bilayers. The existence of such complex viscosity structures could explain the large variation in the apparent membrane viscosity values found in the literature, depending on technique and probe, both for model membranes and live cells. In HeLa cells, a tumor-derived cell line, our nanoparticle-based viscosity sensor detects a membrane viscosity of ∼190 cP and is able to discriminate between cell membrane and intracellular vesicle localization. Thus, our results show the versatility of the dPGS-ICC nano-conjugate in physicochemical and biomedical applications by adding a new analytical functionality to its medical properties.
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Affiliation(s)
- Katja Ober
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Pierre Volz-Rakebrand
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Johannes Stellmacher
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Robert Brodwolf
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Kai Licha
- Mivenion GmbH , Robert-Koch-Platz 4 , 10115 Berlin , Germany
| | - Rainer Haag
- Institut für Chemie und Biochemie , Freie Universität Berlin , Takustraße 3 , 14195 Berlin , Germany
| | - Ulrike Alexiev
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
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31
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Osella S, Smisdom N, Ameloot M, Knippenberg S. Conformational Changes as Driving Force for Phase Recognition: The Case of Laurdan. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11471-11481. [PMID: 31403301 DOI: 10.1021/acs.langmuir.9b01840] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The development of a universal probe to assess the phase of a lipid membrane is one of the most ambitious goals for fluorescence spectroscopy. The ability of a well-known molecule as Laurdan to reach this aim is here exploited as the behavior of the probe is fully characterized in a dipalmitoylphosphatidylcholine (DPPC) solid gel (So) phase by means of molecular dynamics simulations. Laurdan can take two conformations, depending on whether the carbonyl oxygen points toward the β-position of the naphthalene core (Conf-I) or to the α-position (Conf-II). We observe that Conf-I has an elongated form in this environment, whereas Conf-II takes an L-shape. Interestingly, our theoretical calculations show that these two conformations behave in an opposite way from what is reported in the literature for a DPPC membrane in a liquid disordered (Ld) phase, where Conf-I assumes an L-shape and Conf-II is elongated. Moreover, our results show that in DPPC (So) no intermixing between the conformations is present, whereas it has been seen in a fluid environment such as DOPC (Ld). Through a careful analysis of angle distributions and by means of the rotational autocorrelation function, we predict that the two conformers of Laurdan behave differently in different membrane environments.
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Affiliation(s)
- Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies , University of Warsaw , Banacha 2C , 02-097 Warsaw , Poland
| | - Nick Smisdom
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
| | - Marcel Ameloot
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
| | - Stefan Knippenberg
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
- Department of Theoretical Chemistry and Biology, School of Biotechnology , Royal Institute of Technology , SE-10691 Stockholm , Sweden
- RCPTM, Department of Physical Chemistry, Fac. Sciences , Palacký University , 771 46 Olomouc , Czech Republic
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32
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Rapid formation of Small Unilamellar Vesicles (SUV) through low-frequency sonication: An innovative approach. Colloids Surf B Biointerfaces 2019; 181:837-844. [DOI: 10.1016/j.colsurfb.2019.06.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/13/2019] [Accepted: 06/13/2019] [Indexed: 02/05/2023]
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Garg S, Liu Y, Perez-Salas U, Porcar L, Butler PD. Anomalous inter-membrane cholesterol transport in fluid phase phosphoserine vesicles driven by headgroup ordered to disordered entropic transition. Chem Phys Lipids 2019; 223:104779. [PMID: 31153912 PMCID: PMC11132670 DOI: 10.1016/j.chemphyslip.2019.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/20/2019] [Indexed: 10/26/2022]
Abstract
POPS is highly enriched in the inner leaflet of the plasma membrane. Here we present measurements of inter-membrane cholesterol transport rates in POPS vesicles. We find that the cholesterol transport kinetics are not only an order of magnitude slower than in POPC lipids at near physiological temperatures, they exhibit a surprising discontinuous Arrhenius behavior around 48 °C. Moreover, thermodynamic analysis suggests that for biologically relevant temperatures, below the discontinuity, the exchange of cholesterol is entropically dominated while it is enthalpically driven, as is the case in POPC vesicles, above that discontinuity. Using the polar fluorescent probe Laurdan we found that POPS fluid membranes retain a large degree of order in the headgroup region for temperatures below the discontinuity but undergo an order-to-disorder transition in the region coinciding with the discontinuity in the transport of cholesterol in POPS membranes providing an explanation not only for the discontinuity but for the entropic dominance at physiological temperatures.
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Affiliation(s)
- Sumit Garg
- Physics Department, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yangmingyue Liu
- Physics Department, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Ursula Perez-Salas
- Physics Department, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Lionel Porcar
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Paul D Butler
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, USA
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34
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Ríos Colombo NS, Chalón MC, Dupuy FG, Gonzalez CF, Bellomio A. The case for class II bacteriocins: A biophysical approach using "suicide probes" in receptor-free hosts to study their mechanism of action. Biochimie 2019; 165:183-195. [PMID: 31381962 DOI: 10.1016/j.biochi.2019.07.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/26/2019] [Indexed: 11/29/2022]
Abstract
Class II bacteriocins are unmodified membrane-active peptides that act over a narrow spectrum of target bacteria. They bind a specific receptor protein on the membrane to form a pore, leading to membrane permeabilization and cell death. However, little is known about the molecular events triggering the pore formation after the bacteriocin recognizes the receptor. It is not clear yet if the pore is the same receptor forced into an open conformation or if the pore results from the bacteriocin insertion and oligomeric assembly in the lipid bilayer. In order to reveal which model is more suitable to explain the toxicity mechanism, in this work we use chimeric peptides, resulting from the fusion of the bitopic membrane protein EtpM with different class II bacteriocins: enterocin CRL35, pediocin PA-1 and microcin V. E. coli strains lacking the specific receptors for these bacteriocins were chosen as expression hosts. As these constructs display a lethal effect when they are heterologously expressed, they are called "suicide probes". The results suggest that, indeed, the specific receptor would act as a docking molecule more than as a structural piece of the pore, as long as the bacteriocin is somehow anchored to the membrane. These set of chimeric peptides also represent an in vivo system that allows to study the interaction of the bacteriocins with real bacterial membranes, instead of model membranes. Hence, the effects of these suicide probes in membrane fluidity and transmembrane potential were also assessed, using fluorescence spectroscopy. The data show that the different suicide probes are able to increase phospholipid order and depolarize the membranes of receptor-free bacterial cells.
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Affiliation(s)
- N S Ríos Colombo
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT, Chacabuco 461, San Miguel de Tucumán, T4000ILI, Argentina
| | - M C Chalón
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT, Chacabuco 461, San Miguel de Tucumán, T4000ILI, Argentina
| | - F G Dupuy
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT, Chacabuco 461, San Miguel de Tucumán, T4000ILI, Argentina
| | - C F Gonzalez
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Sciences, University of Florida, 2033 Mowry road, PO Box 103610, Gainesville, FL, 32610-3610, USA
| | - A Bellomio
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT, Chacabuco 461, San Miguel de Tucumán, T4000ILI, Argentina.
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35
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Zhang H, Wei X, Liu L, Zhang Q, Jiang W. The role of positively charged sites in the interaction between model cell membranes and γ-Fe 2O 3 NPs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 673:414-423. [PMID: 30991331 DOI: 10.1016/j.scitotenv.2019.04.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/04/2019] [Accepted: 04/06/2019] [Indexed: 06/09/2023]
Abstract
The various applications of iron oxide nanoparticles (NPs) in clinical care and wastewater treatment are rapidly developing, thus their biological safety is worth attention. The electrostatic interaction between cell membranes and NPs is the key mechanism behind membrane damage and membrane penetration. Cell membranes are generally negatively charged with a few positively charged domains. The role of the positively charged sites in the NP-membrane interaction needs further investigation. In this study, the ratio of the positively charged sites was adjusted in two model cell membranes: giant and small unilamellar vesicles (GUVs and SUVs). After exposure to negatively charged γ-Fe2O3 NPs, the adhesion of NPs on the membranes and the induced membrane disruption were studied by microscopic observation and quartz crystal microbalance (QCM) monitoring. γ-Fe2O3 NPs adhered to and disrupted the membranes containing even few positively charged sites, although the whole membrane exhibited a negative zeta potential and hence electrostatically repels the NPs. The number of adhered γ-Fe2O3 NPs increased remarkably on membranes with overall positive zeta potential, but more serious disruption happened to membranes with higher ratios of positively charged sites. Therefore, the membrane rupture was more correlated to the number of positively charged sites than to the zeta potential of the whole membrane. In addition, exposure to γ-Fe2O3 NPs decreased the order of the lipid molecules and hence increased the fluidity of the membrane phase, and the most significant phase change occurred in the negatively charged membrane with the highest ratio of positively charged sites. Infrared spectra indicated that γ-Fe2O3 NPs probably interact with the membranes via the phosphodiester and trimethylamine groups in the lipid head groups. Our research furthers our knowledge of the electrostatic interaction between NPs and cell membranes, which should help to predict the biological effects of γ-Fe2O3 NPs.
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Affiliation(s)
- Hanqiong Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Xiaoran Wei
- School of Public Health, Qingdao University, Qingdao 266021, China
| | - Ling Liu
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Wei Jiang
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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36
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Nomura K, Yamaguchi T, Mori S, Fujikawa K, Nishiyama KI, Shimanouchi T, Tanimoto Y, Morigaki K, Shimamoto K. Alteration of Membrane Physicochemical Properties by Two Factors for Membrane Protein Integration. Biophys J 2019; 117:99-110. [PMID: 31164197 PMCID: PMC6626835 DOI: 10.1016/j.bpj.2019.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/08/2019] [Accepted: 05/14/2019] [Indexed: 12/01/2022] Open
Abstract
After a nascent chain of a membrane protein emerges from the ribosomal tunnel, the protein is integrated into the cell membrane. This process is controlled by a series of proteinaceous molecular devices, such as signal recognition particles and Sec translocons. In addition to these proteins, we discovered two endogenous components regulating membrane protein integration in the inner membrane of Escherichia coli. The integration is blocked by diacylglycerol (DAG), whereas the blocking is relieved by a glycolipid named membrane protein integrase (MPIase). Here, we investigated the influence of these integration-blocking and integration-promoting factors on the physicochemical properties of membrane lipids via solid-state NMR and fluorescence measurements. These factors did not have destructive effects on membrane morphology because the membrane maintained its lamellar structure and did not fuse in the presence of DAG and/or MPIase at their effective concentrations. We next focused on membrane flexibility. DAG did not affect the mobility of the membrane surface, whereas the sugar chain in MPIase was highly mobile and enhanced the flexibility of membrane lipid headgroups. Comparison with a synthetic MPIase analog revealed the effects of the long sugar chain on membrane properties. The acyl chain order inside the membrane was increased by DAG, whereas the increase was cancelled by the addition of MPIase. MPIase also loosened the membrane lipid packing. Focusing on the transbilayer movement, MPIase reduced the rapid flip-flop motion of DAG. On the other hand, MPIase could not compensate for the diminished lateral diffusion by DAG. These results suggest that by manipulating the membrane lipids dynamics, DAG inhibits the protein from contacting the inner membrane, whereas the flexible long sugar chain of MPIase increases the opportunity for interaction between the membrane and the protein, leading to membrane integration of the newly formed protein.
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Affiliation(s)
- Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
| | - Toshiyuki Yamaguchi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Shoko Mori
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Ken-Ichi Nishiyama
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | | | - Yasushi Tanimoto
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | | | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
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37
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Watanabe N, Suga K, Slotte JP, Nyholm TKM, Umakoshi H. Lipid-Surrounding Water Molecules Probed by Time-Resolved Emission Spectra of Laurdan. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:6762-6770. [PMID: 31021095 DOI: 10.1021/acs.langmuir.9b00303] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The hydration states of the interfacial region of lipid bilayers were investigated on the basis of the time-resolved emission spectra (TRES) analysis of 6-lauroyl-2-dimethylamino naphthalene (Laurdan), a common fluorescence probe used to analyze membrane hydration. TRES derived from long and short lifetime components were extracted from samples of different lipid species: 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl- sn-glycero-3-phosphocholine (DOPC), d- erythro- N-palmitoyl-sphingosylphosphorylcholine (PSM), and a DOPC/PSM binary bilayer system. Neither lifetime component (short or long) corresponded with the hydration properties; the short lifetime component of DOPC (1.97 ns) exhibited a peak at 440 nm, and the long lifetime components of DPPC and PSM (7.76 and 7.77 ns, respectively) exhibited peaks at the same wavelength. This similarity arose from the competition between the collisional quenching and the hydration effects of water molecules. Herein, this phenomenon was investigated using a plot of the lifetime τ and the peak position λ (τ vs λ plot), simultaneously visualizing both effects by deconvoluting the TRES. On the basis of collisional quenching theory, the distribution of the water population per lipid (water map) was generated. According to this theory, the τ vs λ plot was applied to the water map and the calculation of the number of water molecules per lipid, which is consistent with previous reports. This approach provides novel insights for the analysis of molecular hydration states using the fluorescence of Laurdan.
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Affiliation(s)
- Nozomi Watanabe
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - Keishi Suga
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FI-20520 , Finland
| | - Thomas K M Nyholm
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FI-20520 , Finland
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
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38
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Saturated fatty acids induce NLRP3 activation in human macrophages through K + efflux resulting from phospholipid saturation and Na, K-ATPase disruption. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1017-1030. [PMID: 30953761 DOI: 10.1016/j.bbalip.2019.04.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 12/29/2022]
Abstract
NLRP3 inflammasome plays a key role in Western diet-induced systemic inflammation and was recently shown to mediate long-lasting trained immunity in myeloid cells. Saturated fatty acids (SFAs) are sterile triggers able to induce the assembly of the NLRP3 inflammasome in macrophages, leading to IL-1β secretion while unsaturated ones (UFAs) prevent SFAs-mediated NLRP3 activation. Unlike previous studies using LPS-primed bone marrow derived macrophages, we do not see any ROS or IRE-1α involvement in SFAs-mediated NLRP3 activation in human monocytes-derived macrophages. Rather we show that SFAs need to enter the cells and to be activated into acyl-CoA to lead to NLRP3 activation in human macrophages. However, their β-oxidation is dispensable. Instead, they are channeled towards phospholipids but redirected towards lipid droplets containing triacylglycerol in the presence of UFAs. Lipidomic analyses and Laurdan fluorescence experiments demonstrate that SFAs induce a dramatic saturation of phosphatidylcholine (PC) correlated with a loss of membrane fluidity, both events inhibited by UFAs. The silencing of CCTα, the key enzyme in PC synthesis, prevents SFA-mediated NLRP3 activation, demonstrating the essential role of the de novo PC synthesis. This SFA-induced membrane remodeling promotes a disruption of the plasma membrane Na, K-ATPase, instigating a K+ efflux essential and sufficient for NLRP3 activation. This work opens novel therapeutic avenues to interfere with Western diet-associated diseases such as those targeting the glycerolipid pathway.
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Watanabe N, Goto Y, Suga K, Nyholm TKM, Slotte JP, Umakoshi H. Solvatochromic Modeling of Laurdan for Multiple Polarity Analysis of Dihydrosphingomyelin Bilayer. Biophys J 2019; 116:874-883. [PMID: 30819567 DOI: 10.1016/j.bpj.2019.01.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 01/17/2019] [Accepted: 01/28/2019] [Indexed: 01/28/2023] Open
Abstract
The hydration properties of the interface between lipid bilayers and bulk water are important for determining membrane characteristics. Here, the emission properties of a solvent-sensitive fluorescence probe, 6-lauroyl-2-dimethylamino naphthalene (Laurdan), were evaluated in lipid bilayer systems composed of the sphingolipids D-erythro-N-palmitoyl-sphingosylphosphorylcholine (PSM) and D-erythro-N-palmitoyl-dihydrosphingomyelin (DHPSM). The glycerophospholipids 1-palmitoyl-2-palmitoyl-sn-glycero-3-phosphocholine and 1-oleoyl-2-oleoyl-sn-glycero-3-phosphocholine were used as controls. The fluorescence properties of Laurdan in sphingolipid bilayers indicated multiple excited states according to the results obtained from the emission spectra, fluorescence anisotropy, and the center-of-mass spectra during the decay time. Deconvolution of the Laurdan emission spectra into four components based on the solvent model enabled us to identify the varieties of hydration and the configurational states derived from intermolecular hydrogen bonding in sphingolipids. Sphingolipids showed specific, interfacial hydration properties stemming from their intra- and intermolecular hydrogen bonds. Particularly, the Laurdan in DHPSM revealed more hydrated properties compared to PSM, even though DHPSM has a higher Tm than PSM. Because DHPSM forms hydrogen bonds with water molecules (in 2NH configurational functional groups), the interfacial region of the DHPSM bilayer was expected to be in a highly polar environment. The careful analysis of Laurdan emission spectra through the four-component deconvolution in this study provides important insights for understanding the multiple polarity in the lipid membrane.
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Affiliation(s)
- Nozomi Watanabe
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Yuka Goto
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Keishi Suga
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Thomas K M Nyholm
- Department of Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - J Peter Slotte
- Department of Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Hiroshi Umakoshi
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan.
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40
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Lebecque S, Lins L, Dayan FE, Fauconnier ML, Deleu M. Interactions Between Natural Herbicides and Lipid Bilayers Mimicking the Plant Plasma Membrane. FRONTIERS IN PLANT SCIENCE 2019; 10:329. [PMID: 30936889 PMCID: PMC6431664 DOI: 10.3389/fpls.2019.00329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/28/2019] [Indexed: 05/06/2023]
Abstract
Natural phytotoxic compounds could become an alternative to traditional herbicides in the framework of sustainable agriculture. Nonanoic acid, sarmentine and sorgoleone are such molecules extracted from plants and able to inhibit the growth of various plant species. However, their mode of action is not fully understood and despite clues indicating that they could affect the plant plasma membrane, molecular details of such phenomenon are lacking. In this paper, we investigate the interactions between those natural herbicides and artificial bilayers mimicking the plant plasma membrane. First, their ability to affect lipid order and fluidity is evaluated by means of fluorescence measurements. It appears that sorgoleone has a clear ordering effect on lipid bilayers, while nonanoic acid and sarmentine induce no or little change to these parameters. Then, a thermodynamic characterization of interactions of each compound with lipid vesicles is obtained with isothermal titration calorimetry, and their respective affinity for bilayers is found to be ranked as follows: sorgoleone > sarmentine > nonanoic acid. Finally, molecular dynamics simulations give molecular details about the location of each compound within a lipid bilayer and confirm the rigidifying effect of sorgoleone. Data also suggest that mismatch in alkyl chain length between nonanoic acid or sarmentine and lipid hydrophobic tails could be responsible for bilayer destabilization. Results are discussed regarding their implications for the phytotoxicity of these compounds.
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Affiliation(s)
- Simon Lebecque
- TERRA, Laboratory of Molecular Biophysics at Interfaces, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
- TERRA – AgricultureIsLife, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Laurence Lins
- TERRA, Laboratory of Molecular Biophysics at Interfaces, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Franck E. Dayan
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, United States
| | - Marie-Laure Fauconnier
- General and Organic Chemistry Laboratory, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Magali Deleu
- TERRA, Laboratory of Molecular Biophysics at Interfaces, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
- *Correspondence: Magali Deleu,
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Bessa LJ, Ferreira M, Gameiro P. Data on Laurdan spectroscopic analyses to compare membrane fluidity between susceptible and multidrug-resistant bacteria. Data Brief 2018; 21:128-132. [PMID: 30338286 PMCID: PMC6187016 DOI: 10.1016/j.dib.2018.09.106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 09/28/2018] [Indexed: 12/02/2022] Open
Abstract
The data presented are related to the research article entitled "Evaluation of membrane fluidity of multidrug-resistant isolates of Escherichia coli and Staphylococcus aureus in presence and absence of antibiotics" (Bessa et al., 2018) [1]. This data article provides a dataset that includes emission spectra of Laurdan-labeled bacteria, namely of three Escherichia coli and three Staphylococcus aureus strains. Laurdan (6-dodecanoyl-2-dimethylaminonaphthalene) is a popular fluorescence probe used to assess membrane fluidity. Laurdan detects changes in membrane phase properties through its sensitivity to the polarity of the environment in the bilayer. Polarity changes are reflected by shifts in the Laurdan fluorescence emission spectrum that can be quantified by calculating the excitation generalized polarization (GPexc ).
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Affiliation(s)
- Lucinda J. Bessa
- LAQV/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
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Evaluation of membrane fluidity of multidrug-resistant isolates of Escherichia coli and Staphylococcus aureus in presence and absence of antibiotics. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 181:150-156. [PMID: 29567316 DOI: 10.1016/j.jphotobiol.2018.03.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/29/2018] [Accepted: 03/04/2018] [Indexed: 11/24/2022]
Abstract
In the face of the serious problem of antimicrobial resistance and the global dissemination of multidrug-resistant (MDR) bacteria, it is relevant to deeply study such bacteria both genetically and phenotypically. It is well known that bacteria have the ability to modify the biophysical properties of their cytoplasmic membranes, namely fluidity, in order to survive and thrive in hostile environments. The aim of this study was to assess and compare the membrane fluidity among multidrug-resistant (MDR) isolates of Escherichia coli and Staphylococcus aureus in absence and in presence of antibiotics (ceftazidime or ciprofloxacin). The membrane fluidity was monitored at 24-h intervals up to three days and at the sixth day, by measuring the anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) and the generalized polarization (GP) of Laurdan (6-dodecanoyl-2-dimethylaminonaphthalene). The anisotropy values as well as the Laurdan excitation GP (GPexc) values obtained from all three E. coli strains (two MDR isolates and one susceptible reference strain) were quite similar and indicative of a very alike membrane phospholipid composition, regardless harboring or not resistance to multiple antimicrobials. Nonetheless, in the case of S. aureus, the anisotropy values were more increased in methicillin-resistant S. aureus (MRSA) isolates in comparison to the reference strain, meaning they have a less fluid membrane. Equally, GPexc values were statistically different among the three S. aureus strains and showed that the two MRSA isolates had more rigid membranes than the susceptible strain. The exposition of MDR isolates of S. aureus to subinhibitory concentrations of ciprofloxacin did not affect neither the anisotropy values nor the GPexc values, therefore, not altering membrane fluidity. Membrane integrity, assessed by the Live/Dead staining, of all strains and conditions studied was maintained over the six days. Thus, these preliminary studies on membrane properties of MDR isolates demonstrate that i) MRSA seem to have a more rigid membrane that susceptible S. aureus and ii) the presence of subinhibitory concentrations of antibiotics does not significantly alter the membrane fluidity of S. aureus, regardless being MDR or susceptible, but slightly affect the membrane fluidity of E. coli.
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Mazeres S, Fereidouni F, Joly E. Using spectral decomposition of the signals from laurdan-derived probes to evaluate the physical state of membranes in live cells. F1000Res 2017; 6:763. [PMID: 28663788 PMCID: PMC5473435 DOI: 10.12688/f1000research.11577.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/28/2017] [Indexed: 01/22/2023] Open
Abstract
Background: We wanted to investigate the physical state of biological membranes in live cells under the most physiological conditions possible. Methods: For this we have been using laurdan, C-laurdan or M-laurdan to label a variety of cells, and a biphoton microscope equipped with both a thermostatic chamber and a spectral analyser. We also used a flow cytometer to quantify the 450/530 nm ratio of fluorescence emissions by whole cells. Results: We find that using all the information provided by spectral analysis to perform spectral decomposition dramatically improves the imaging resolution compared to using just two channels, as commonly used to calculate generalized polarisation (GP). Coupled to a new plugin called Fraction Mapper, developed to represent the fraction of light intensity in the first component in a stack of two images, we obtain very clear pictures of both the intra-cellular distribution of the probes, and the polarity of the cellular environments where the lipid probes are localised. Our results lead us to conclude that, in live cells kept at 37°C, laurdan, and M-laurdan to a lesser extent, have a strong tendency to accumulate in the very apolar environment of intra-cytoplasmic lipid droplets, but label the plasma membrane (PM) of mammalian cells ineffectively. On the other hand, C-laurdan labels the PM very quickly and effectively, and does not detectably accumulate in lipid droplets. Conclusions: From using these probes on a variety of mammalian cell lines, as well as on cells from
Drosophila and
Dictyostelium discoideum, we conclude that, apart from the lipid droplets, which are very apolar, probes in intracellular membranes reveal a relatively polar and hydrated environment, suggesting a very marked dominance of liquid disordered states. PMs, on the other hand, are much more apolar, suggesting a strong dominance of liquid ordered state, which fits with their high sterol contents.
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Affiliation(s)
- Serge Mazeres
- Membrane and DNA Dynamics Team, Institut de Pharmacologie et de Biologie Structurale, CNRS, Université de Toulouse, Toulouse, F-31077, France
| | - Farzad Fereidouni
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, CA 95817, CA, 4400, USA
| | - Etienne Joly
- Membrane and DNA Dynamics Team, Institut de Pharmacologie et de Biologie Structurale, CNRS, Université de Toulouse, Toulouse, F-31077, France
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Mazeres S, Fereidouni F, Joly E. Using spectral decomposition of the signals from laurdan-derived probes to evaluate the physical state of membranes in live cells. F1000Res 2017; 6:763. [PMID: 28663788 DOI: 10.12688/f1000research.11577.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/26/2017] [Indexed: 12/13/2022] Open
Abstract
Background: We wanted to investigate the physical state of biological membranes in live cells under the most physiological conditions possible. Methods: For this we have been using laurdan, C-laurdan or M-laurdan to label a variety of cells, and a biphoton microscope equipped with both a thermostatic chamber and a spectral analyser. We also used a flow cytometer to quantify the 450/530 nm ratio of fluorescence emissions by whole cells. Results: We find that using all the information provided by spectral analysis to perform spectral decomposition dramatically improves the imaging resolution compared to using just two channels, as commonly used to calculate generalized polarisation (GP). Coupled to a new plugin called Fraction Mapper, developed to represent the fraction of light intensity in the first component in a stack of two images, we obtain very clear pictures of both the intra-cellular distribution of the probes, and the polarity of the cellular environments where the lipid probes are localised. Our results lead us to conclude that, in live cells kept at 37°C, laurdan, and M-laurdan to a lesser extent, have a strong tendency to accumulate in the very apolar environment of intra-cytoplasmic lipid droplets, but label the plasma membrane (PM) of mammalian cells ineffectively. On the other hand, C-laurdan labels the PM very quickly and effectively, and does not detectably accumulate in lipid droplets. Conclusions: From using these probes on a variety of mammalian cell lines, as well as on cells from Drosophila and Dictyostelium discoideum, we conclude that, apart from the lipid droplets, which are very apolar, probes in intracellular membranes reveal a relatively polar and hydrated environment, suggesting a very marked dominance of liquid disordered states. PMs, on the other hand, are much more apolar, suggesting a strong dominance of liquid ordered state, which fits with their high sterol contents.
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Affiliation(s)
- Serge Mazeres
- Membrane and DNA Dynamics Team, Institut de Pharmacologie et de Biologie Structurale, CNRS, Université de Toulouse, Toulouse, F-31077, France
| | - Farzad Fereidouni
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, CA 95817, CA, 4400, USA
| | - Etienne Joly
- Membrane and DNA Dynamics Team, Institut de Pharmacologie et de Biologie Structurale, CNRS, Université de Toulouse, Toulouse, F-31077, France
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