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Ahn JH, Johnny CL, Chenoweth DM. Duo-Chol: A Photoconvertible Live Cell Imaging Tool for Tracking Cholesterol. Bioconjug Chem 2024; 35:890-896. [PMID: 38913976 DOI: 10.1021/acs.bioconjchem.4c00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Investigating cholesterol trafficking pathways continues to be of significant scientific interest owing to its homeostasis being associated with several debilitating cardiovascular and neurodegenerative diseases including atherosclerosis, Niemann-Pick's disease, Alzheimer's disease, and Parkinson's disease. To further our understanding of cholesterol trafficking, it is imperative to develop new fluorescent probes that possess improved photostability, low efflux, and high spatial and temporal resolution for live-cell imaging. In this study, we developed a photoconvertible fluorescent cholesterol analog, Duo-Chol, enabling the improved spatiotemporal fluorescence imaging of the dynamic localization of cholesterol in live cells. This tool provides a unique and powerful approach to interrogating cholesterol dynamics, addressing the limitations of existing methods, and expanding our ability to probe the biological role of sterols in living cells.
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Affiliation(s)
- June H Ahn
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Christopher L Johnny
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - David M Chenoweth
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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2
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Akkerman V, Scheidt HA, Reinholdt P, Bashawat M, Szomek M, Lehmann M, Wessig P, Covey DF, Kongsted J, Müller P, Wüstner D. Natamycin interferes with ergosterol-dependent lipid phases in model membranes. BBA ADVANCES 2023; 4:100102. [PMID: 37691996 PMCID: PMC10482743 DOI: 10.1016/j.bbadva.2023.100102] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023] Open
Abstract
Natamycin is an antifungal polyene macrolide that is used as a food preservative but also to treat fungal keratitis and other yeast infections. In contrast to other polyene antimycotics, natamycin does not form ion pores in the plasma membrane, but its mode of action is poorly understood. Using nuclear magnetic resonance (NMR) spectroscopy of deuterated sterols, we find that natamycin slows the mobility of ergosterol and cholesterol in liquid-ordered (Lo) membranes to a similar extent. This is supported by molecular dynamics (MD) simulations, which additionally reveal a strong impact of natamycin dimers on sterol dynamics and water permeability. Interference with sterol-dependent lipid packing is also reflected in a natamycin-mediated increase in membrane accessibility for dithionite, particularly in bilayers containing ergosterol. NMR experiments with deuterated sphingomyelin (SM) in sterol-containing membranes reveal that natamycin reduces phase separation and increases lipid exchange in bilayers with ergosterol. In ternary lipid mixtures containing monounsaturated phosphatidylcholine, saturated SM, and either ergosterol or cholesterol, natamycin interferes with phase separation into Lo and liquid-disordered (Ld) domains, as shown by NMR spectroscopy. Employing the intrinsic fluorescence of natamycin in ultraviolet-sensitive microscopy, we can visualize the binding of natamycin to giant unilamellar vesicles (GUVs) and find that it has the highest affinity for the Lo phase in GUVs containing ergosterol. Our results suggest that natamycin specifically interacts with the sterol-induced ordered phase, in which it disrupts lipid packing and increases solvent accessibility. This property is particularly pronounced in ergosterol containing membranes, which could underlie the selective antifungal activity of natamycin.
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Affiliation(s)
- Vibeke Akkerman
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Holger A. Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107, Leipzig, Germany
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Mohammad Bashawat
- Department of Biology, Humboldt University Berlin, Invalidenstr. 43, D-10115, Berlin, Germany
| | - Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Max Lehmann
- Institute for Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam, Germany
| | - Pablo Wessig
- Institute for Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam, Germany
| | - Douglas F. Covey
- Department of Developmental Biology, Washington University, St. Louis, MO, 63110, USA
- Taylor Family Institute for Innovative Psychiatric Research, St. Louis, Missouri, USA
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230, Odense M, Denmark
| | - Peter Müller
- Department of Biology, Humboldt University Berlin, Invalidenstr. 43, D-10115, Berlin, Germany
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230, Odense M, Denmark
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3
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Subra M, Dezi M, Bigay J, Lacas-Gervais S, Di Cicco A, Araújo ARD, Abélanet S, Fleuriot L, Debayle D, Gautier R, Patel A, Roussi F, Antonny B, Lévy D, Mesmin B. VAP-A intrinsically disordered regions enable versatile tethering at membrane contact sites. Dev Cell 2023; 58:121-138.e9. [PMID: 36693319 DOI: 10.1016/j.devcel.2022.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/21/2022] [Accepted: 12/20/2022] [Indexed: 01/24/2023]
Abstract
Membrane contact sites (MCSs) are heterogeneous in shape, composition, and dynamics. Despite this diversity, VAP proteins act as receptors for multiple FFAT motif-containing proteins and drive the formation of most MCSs that involve the endoplasmic reticulum (ER). Although the VAP-FFAT interaction is well characterized, no model explains how VAP adapts to its partners in various MCSs. We report that VAP-A localization to different MCSs depends on its intrinsically disordered regions (IDRs) in human cells. VAP-A interaction with PTPIP51 and VPS13A at ER-mitochondria MCS conditions mitochondria fusion by promoting lipid transfer and cardiolipin buildup. VAP-A also enables lipid exchange at ER-Golgi MCS by interacting with oxysterol-binding protein (OSBP) and CERT. However, removing IDRs from VAP-A restricts its distribution and function to ER-mitochondria MCS. Our data suggest that IDRs do not modulate VAP-A preference toward specific partners but do adjust their geometry to MCS organization and lifetime constraints. Thus, IDR-mediated VAP-A conformational flexibility ensures membrane tethering plasticity and efficiency.
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Affiliation(s)
- Mélody Subra
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Manuela Dezi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Joëlle Bigay
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Sandra Lacas-Gervais
- Université Côte d'Azur, Centre Commun de Microscopie Appliquée, Parc Valrose, 06000 Nice, France
| | - Aurélie Di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Ana Rita Dias Araújo
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Sophie Abélanet
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Lucile Fleuriot
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Delphine Debayle
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Romain Gautier
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Amanda Patel
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Fanny Roussi
- Institut de Chimie des Substances Naturelles, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Bruno Antonny
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Bruno Mesmin
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France.
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4
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Berthiot R, Giudice N, Douce L. Luminescent Imidazolium Salts as Bright Multi‐Faceted Tools for Biology. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Romain Berthiot
- Département des Matériaux Organiques Institut de Physique et de Chimie des Matériaux de Strasbourg (UMR 7504) Université de Strasbourg/CNRS 23 Rue du Loess 67000 Strasbourg France
| | - Nicolas Giudice
- Département des Matériaux Organiques Institut de Physique et de Chimie des Matériaux de Strasbourg (UMR 7504) Université de Strasbourg/CNRS 23 Rue du Loess 67000 Strasbourg France
| | - Laurent Douce
- Département des Matériaux Organiques Institut de Physique et de Chimie des Matériaux de Strasbourg (UMR 7504) Université de Strasbourg/CNRS 23 Rue du Loess 67000 Strasbourg France
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5
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Desai R, East DA, Hardy L, Faccenda D, Rigon M, Crosby J, Alvarez MS, Singh A, Mainenti M, Hussey LK, Bentham R, Szabadkai G, Zappulli V, Dhoot GK, Romano LE, Xia D, Coppens I, Hamacher-Brady A, Chapple JP, Abeti R, Fleck RA, Vizcay-Barrena G, Smith K, Campanella M. Mitochondria form contact sites with the nucleus to couple prosurvival retrograde response. SCIENCE ADVANCES 2020; 6:eabc9955. [PMID: 33355129 PMCID: PMC11206220 DOI: 10.1126/sciadv.abc9955] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 11/13/2020] [Indexed: 05/25/2023]
Abstract
Mitochondria drive cellular adaptation to stress by retro-communicating with the nucleus. This process is known as mitochondrial retrograde response (MRR) and is induced by mitochondrial dysfunction. MRR results in the nuclear stabilization of prosurvival transcription factors such as the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Here, we demonstrate that MRR is facilitated by contact sites between mitochondria and the nucleus. The translocator protein (TSPO) by preventing the mitophagy-mediated segregation o mitochonria is required for this interaction. The complex formed by TSPO with the protein kinase A (PKA), via the A-kinase anchoring protein acyl-CoA binding domain containing 3 (ACBD3), established the tethering. The latter allows for cholesterol redistribution of cholesterol in the nucleus to sustain the prosurvival response by blocking NF-κB deacetylation. This work proposes a previously unidentified paradigm in MRR: the formation of contact sites between mitochondria and nucleus to aid communication.
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Affiliation(s)
- Radha Desai
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Daniel A East
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Liana Hardy
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Danilo Faccenda
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Manuel Rigon
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - James Crosby
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - María Soledad Alvarez
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Aarti Singh
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Marta Mainenti
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Laura Kuhlman Hussey
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Robert Bentham
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, London WC1E 6BT, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, London WC1E 6BT, UK
- Department of Biomedical Science, University of Padua, Via Ugo Bassi, 35131 Padua, Italy
- Francis Crick Institute, Midland Road, London NW1 AT, UK
| | - Valentina Zappulli
- Department of Comparative Biomedicine and Food Sciences, University of Padua, Viale dell'Universita' 16, 35020 Legnaro (PD), Italy
| | - Gurtej K Dhoot
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Lisa E Romano
- William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary University of London, London EC1M 6BQ, UK
| | - Dong Xia
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK
| | - Isabelle Coppens
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Baltimore, Baltimore, MD 21205, USA
| | - Anne Hamacher-Brady
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Baltimore, Baltimore, MD 21205, USA
| | - J Paul Chapple
- William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary University of London, London EC1M 6BQ, UK
| | - Rosella Abeti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, London SE1 1UL, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, King's College London, London SE1 1UL, UK
| | - Kenneth Smith
- Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK.
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, London WC1E 6BT, UK
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6
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Szomek M, Moesgaard L, Reinholdt P, Haarhøj Hald SB, Petersen D, Krishnan K, Covey DF, Kongsted J, Wüstner D. Membrane organization and intracellular transport of a fluorescent analogue of 27-hydroxycholesterol. Chem Phys Lipids 2020; 233:105004. [PMID: 33137329 DOI: 10.1016/j.chemphyslip.2020.105004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/29/2020] [Accepted: 10/24/2020] [Indexed: 11/30/2022]
Abstract
Oxysterols are cholesterol metabolites with multiple functions in controlling cellular homeostasis. In particular, 27-hydroxycholesterol (27-OH-Chol) has been shown to regulate a variety of physiological functions, but little is known about its uptake, intracellular trafficking, and efflux from cells. This is largely due to a lack of suitable analogs of 27-OH-Chol, which mimic this oxysterol closely. Here, we present the intrinsically fluorescent 27-hydroxy-cholestatrienol (27-OH-CTL), which differs from 27-OH-Chol only by having two additional double bonds in the steroid ring system. Based on molecular dynamics (MD) simulations, we show that 27-OH-CTL possesses almost identical membrane properties compared to 27-OH-Chol. By comparative imaging of 27-OH-CTL and of the cholesterol analogue cholestatrienol (CTL) in living cells, we assess the impact of a single hydroxy group on sterol trafficking. We find that human fibroblasts take up more CTL than 27-OH-CTL, but efflux the oxysterol analogue more efficiently. For both sterols, efflux includes shedding of vesicles from the plasma membrane. Intracellular, 27-OH-CTL accumulates primarily in lipid droplets (LDs), while CTL is mostly found in endosomes and lysosomes. Using fluorescence recovery after photobleaching (FRAP), we find for both sterols a rapidly exchanging pool, which moves orders of magnitude faster than sterol containing vesicles and LDs. In summary, by applying a new fluorescent derivative of 27-OH-Chol we demonstrate that human cells can distinguish sterols based on a single hydroxy group in the side chain, resulting in different transport itineraries, dynamics, and efflux kinetics. Both intrinsically fluorescent cholesterol and oxysterol analogues show rapid non-vesicular transport in human fibroblasts.
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Affiliation(s)
- Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Laust Moesgaard
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Sophia Bell Haarhøj Hald
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Daniel Petersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University, St. Louis, MO 63110, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University, St. Louis, MO 63110, USA
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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7
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The caveolar-mitochondrial interface: regulation of cellular metabolism in physiology and pathophysiology. Biochem Soc Trans 2020; 48:165-177. [PMID: 32010944 DOI: 10.1042/bst20190388] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/15/2022]
Abstract
The plasma membrane is an important cellular organelle that is often overlooked in terms of a primary factor in regulating physiology and pathophysiology. There is emerging evidence to suggest that the plasma membrane serves a greater purpose than a simple barrier or transporter of ions. New paradigms suggest that the membrane serves as a critical bridge to connect extracellular to intracellular communication particularly to regulate energy and metabolism by forming physical and biochemical associations with intracellular organelles. This review will focus on the relationship of a particular membrane microdomain - caveolae - with mitochondria and the particular implication of this to physiology and pathophysiology.
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8
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Heterocyclic sterol probes for live monitoring of sterol trafficking and lysosomal storage disorders. Sci Rep 2018; 8:14428. [PMID: 30258093 PMCID: PMC6158244 DOI: 10.1038/s41598-018-32776-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 09/14/2018] [Indexed: 12/13/2022] Open
Abstract
The monitoring of intracellular cholesterol homeostasis and trafficking is of great importance because their imbalance leads to many pathologies. Reliable tools for cholesterol detection are in demand. This study presents the design and synthesis of fluorescent probes for cholesterol recognition and demonstrates their selectivity by a variety of methods. The construction of dedicated library of 14 probes was based on heterocyclic (pyridine)-sterol derivatives with various attached fluorophores. The most promising probe, a P1-BODIPY conjugate FP-5, was analysed in detail and showed an intensive labelling of cellular membranes followed by intracellular redistribution into various cholesterol rich organelles and vesicles. FP-5 displayed a stronger signal, with faster kinetics, than the commercial TF-Chol probe. In addition, cells with pharmacologically disrupted cholesterol transport, or with a genetic mutation of cholesterol transporting protein NPC1, exhibited strong and fast FP-5 signal in the endo/lysosomal compartment, co-localizing with filipin staining of cholesterol. Hence, FP-5 has high potential as a new probe for monitoring cholesterol trafficking and its disorders.
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9
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Berzina Z, Solanko LM, Mehadi AS, Jensen MLV, Lund FW, Modzel M, Szomek M, Solanko KA, Dupont A, Nielsen GK, Heegaard CW, Ejsing CS, Wüstner D. Niemann-Pick C2 protein regulates sterol transport between plasma membrane and late endosomes in human fibroblasts. Chem Phys Lipids 2018; 213:48-61. [PMID: 29580834 DOI: 10.1016/j.chemphyslip.2018.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 11/28/2022]
Abstract
Niemann-Pick disease type C2 is a lipid storage disorder in which mutations in the NPC2 protein cause accumulation of lipoprotein-derived cholesterol in late endosomes and lysosomes (LE/LYSs). Whether cholesterol delivered by other means to NPC2 deficient cells also accumulates in LE/LYSs is currently unknown. We show that the close cholesterol analog dehydroergosterol (DHE), when delivered to the plasma membrane (PM) accumulates in LE/LYSs of human fibroblasts lacking functional NPC2. We measured two different time scales of sterol diffusion; while DHE rich LE/LYSs moved by slow anomalous diffusion in disease cells (D ∼ 4.6∙10-4 μm2/sec; α∼0.76), a small pool of sterol could exchange rapidly with D ∼ 3 μm2/s between LE/LYSs, as shown by fluorescence recovery after photobleaching (FRAP). By quantitative lipid mass spectrometry we found that esterification of 13C-labeled cholesterol but not of DHE is reduced 10-fold in disease fibroblasts compared to control cells. Internalized NPC2 rescued the sterol storage phenotype and strongly expanded the dynamic sterol pool seen in FRAP experiments. Together, our study shows that cholesterol esterification and trafficking of sterols between the PM and LE/LYSs depends on a functional NPC2 protein. NPC2 likely acts inside LE/LYSs from where it increases non-vesicular sterol exchange with other organelles.
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Affiliation(s)
- Zane Berzina
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Lukasz M Solanko
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark; Orphazyme ApS, Ole Maales Vej 3, 2200 Copenhagen N, Denmark
| | - Ahmed S Mehadi
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Maria Louise V Jensen
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Frederik W Lund
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Maciej Modzel
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Maria Szomek
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Katarzyna A Solanko
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Alice Dupont
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Gitte Krogh Nielsen
- Department of Molecular Biology and Genetics, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - Christian W Heegaard
- Department of Molecular Biology and Genetics, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - Christer S Ejsing
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, DK-5230 Odense M, Denmark.
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10
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Quantitative Co-Localization and Pattern Analysis of Endo-Lysosomal Cargo in Subcellular Image Cytometry and Validation on Synthetic Image Sets. Methods Mol Biol 2017; 1594:93-128. [PMID: 28456978 DOI: 10.1007/978-1-4939-6934-0_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Late endosomes and lysosomes (LE/LYSs) play a central role in trafficking of endocytic cargo, secretion of exosomes, and hydrolysis of ingested proteins and lipids. Failure in such processes can lead to lysosomal storage disorders in which a particular metabolite accumulates within LE/LYSs. Analysis of endocytic trafficking relies heavily on quantitative fluorescence microscopy, but evaluation of the huge image data sets is challenging and demands computer-assisted statistical tools. Here, we describe how to use SpatTrack ( www.sdu.dk/bmb/spattrack ), an imaging toolbox, which we developed for quantification of the distribution and dynamics of endo-lysosomal cargo from fluorescence images of living cells. First, we explain how to analyze experimental images of endocytic processes in Niemann Pick C2 disease fibroblasts using SpatTrack. We demonstrate how to quantify the location of the sterol-binding protein NPC2 in LE/LYSs relative to cholesterol -rich lysosomal storage organelles (LSOs) stained with filipin. Second, we show how to simulate realistic vesicle patterns in the cell geometry using Markov Chain Monte Carlo and suitable inter-vesicle and cell-vesicle interaction potentials. Finally, we use such synthetic vesicle patterns as "ground truth" for validation of two-channel analysis tools in SpatTrack, revealing their high reliability. An improved version of SpatTrack for microscopy-based quantification of cargo transport through the endo-lysosomal system accompanies this protocol.
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