1
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Synthesis and Characterization of Ceramide-Containing Liposomes as Membrane Models for Different T Cell Subpopulations. J Funct Biomater 2022; 13:jfb13030111. [PMID: 35997449 PMCID: PMC9397063 DOI: 10.3390/jfb13030111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 12/01/2022] Open
Abstract
A fine balance of regulatory (Treg) and conventional CD4+ T cells (Tconv) is required to prevent harmful immune responses, while at the same time ensuring the development of protective immunity against pathogens. As for many cellular processes, sphingolipid metabolism also crucially modulates the Treg/Tconv balance. However, our understanding of how sphingolipid metabolism is involved in T cell biology is still evolving and a better characterization of the tools at hand is required to advance the field. Therefore, we established a reductionist liposomal membrane model system to imitate the plasma membrane of mouse Treg and Tconv with regards to their ceramide content. We found that the capacity of membranes to incorporate externally added azide-functionalized ceramide positively correlated with the ceramide content of the liposomes. Moreover, we studied the impact of the different liposomal preparations on primary mouse splenocytes in vitro. The addition of liposomes to resting, but not activated, splenocytes maintained viability with liposomes containing high amounts of C16-ceramide being most efficient. Our data thus suggest that differences in ceramide post-incorporation into Treg and Tconv reflect differences in the ceramide content of cellular membranes.
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2
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Fink J, Schumacher F, Schlegel J, Stenzel P, Wigger D, Sauer M, Kleuser B, Seibel J. Azidosphinganine enables metabolic labeling and detection of sphingolipid de novo synthesis. Org Biomol Chem 2021; 19:2203-2212. [PMID: 33496698 DOI: 10.1039/d0ob02592e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Here were report the combination of biocompatible click chemistry of ω-azidosphinganine with fluorescence microscopy and mass spectrometry as a powerful tool to elaborate the sphingolipid metabolism. The azide probe was efficiently synthesized over 13 steps starting from l-serine in an overall yield of 20% and was used for live-cell fluorescence imaging of the endoplasmic reticulum in living cells by bioorthogonal click reaction with a DBCO-labeled fluorophore revealing that the incorporated analogue is mainly localized in the endoplasmic membrane like the endogenous species. A LC-MS(/MS)-based microsomal in vitro assay confirmed that ω-azidosphinganine mimics the natural species enabling the identification and analysis of metabolic breakdown products of sphinganine as a key starting intermediate in the complex sphingolipid biosynthetic pathways. Furthermore, the sphinganine-fluorophore conjugate after click reaction was enzymatically tolerated to form its dihydroceramide and ceramide metabolites. Thus, ω-azidosphinganine represents a useful biofunctional tool for metabolic investigations both by in vivo fluorescence imaging of the sphingolipid subcellular localization in the ER and by in vitro high-resolution mass spectrometry analysis. This should reveal novel insights of the molecular mechanisms sphingolipids and their processing enzymes have e.g. in infection.
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Affiliation(s)
- Julian Fink
- Institute of Organic Chemistry, Julius-Maximilians University Würzburg, Am Hubland C1, 97074 Würzburg, Germany.
| | - Fabian Schumacher
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany. and Institute of Nutritional Science, Department of Toxicology, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Jan Schlegel
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians University Würzburg, 97074 Würzburg, Germany.
| | - Philipp Stenzel
- Institute of Organic Chemistry, Julius-Maximilians University Würzburg, Am Hubland C1, 97074 Würzburg, Germany.
| | - Dominik Wigger
- Institute of Nutritional Science, Department of Toxicology, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians University Würzburg, 97074 Würzburg, Germany.
| | - Burkhard Kleuser
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany. and Institute of Nutritional Science, Department of Toxicology, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Jürgen Seibel
- Institute of Organic Chemistry, Julius-Maximilians University Würzburg, Am Hubland C1, 97074 Würzburg, Germany.
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3
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Götz R, Kunz TC, Fink J, Solger F, Schlegel J, Seibel J, Kozjak-Pavlovic V, Rudel T, Sauer M. Nanoscale imaging of bacterial infections by sphingolipid expansion microscopy. Nat Commun 2020; 11:6173. [PMID: 33268771 PMCID: PMC7710728 DOI: 10.1038/s41467-020-19897-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/05/2020] [Indexed: 12/20/2022] Open
Abstract
Expansion microscopy (ExM) enables super-resolution imaging of proteins and nucleic acids on conventional microscopes. However, imaging of details of the organization of lipid bilayers by light microscopy remains challenging. We introduce an unnatural short-chain azide- and amino-modified sphingolipid ceramide, which upon incorporation into membranes can be labeled by click chemistry and linked into hydrogels, followed by 4× to 10× expansion. Confocal and structured illumination microscopy (SIM) enable imaging of sphingolipids and their interactions with proteins in the plasma membrane and membrane of intracellular organelles with a spatial resolution of 10–20 nm. As our functionalized sphingolipids accumulate efficiently in pathogens, we use sphingolipid ExM to investigate bacterial infections of human HeLa229 cells by Neisseria gonorrhoeae, Chlamydia trachomatis and Simkania negevensis with a resolution so far only provided by electron microscopy. In particular, sphingolipid ExM allows us to visualize the inner and outer membrane of intracellular bacteria and determine their distance to 27.6 ± 7.7 nm. Imaging of lipid bilayers using light microscopy is challenging. Here the authors label cells using a short chain click-compatible ceramide to visualize mammalian and bacterial membranes with expansion microscopy.
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Affiliation(s)
- Ralph Götz
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Tobias C Kunz
- Department of Microbiology, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Julian Fink
- Institute for Organic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Franziska Solger
- Department of Microbiology, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jan Schlegel
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jürgen Seibel
- Institute for Organic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Vera Kozjak-Pavlovic
- Department of Microbiology, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Thomas Rudel
- Department of Microbiology, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
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4
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Detection of Functionalized Sphingolipid Analogs in Detergent-Resistant Membranes of Immune Cells. Methods Mol Biol 2020. [PMID: 32770515 DOI: 10.1007/978-1-0716-0814-2_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The analysis of protein enrichment in the detergent-resistant membranes (DRMs) isolated from immune cells enables us to analyze a link between the membrane lipid dynamics and cell activation. Here, we describe the fractionation of detergent-resistant membranes and the correlative analysis of the enrichment of T cell receptor (TCR) and ω-azido-modified synthetic ceramide in those fractions upon TCR stimulation.
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5
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Crivelli SM, Giovagnoni C, Visseren L, Scheithauer AL, de Wit N, den Hoedt S, Losen M, Mulder MT, Walter J, de Vries HE, Bieberich E, Martinez-Martinez P. Sphingolipids in Alzheimer's disease, how can we target them? Adv Drug Deliv Rev 2020; 159:214-231. [PMID: 31911096 DOI: 10.1016/j.addr.2019.12.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/09/2019] [Accepted: 12/31/2019] [Indexed: 01/06/2023]
Abstract
Altered levels of sphingolipids and their metabolites in the brain, and the related downstream effects on neuronal homeostasis and the immune system, provide a framework for understanding mechanisms in neurodegenerative disorders and for developing new intervention strategies. In this review we will discuss: the metabolites of sphingolipids that function as second messengers; and functional aberrations of the pathway resulting in Alzheimer's disease (AD) pathophysiology. Focusing on the central product of the sphingolipid pathway ceramide, we describ approaches to pharmacologically decrease ceramide levels in the brain and we argue on how the sphingolipid pathway may represent a new framework for developing novel intervention strategies in AD. We also highlight the possible use of clinical and non-clinical drugs to modulate the sphingolipid pathway and sphingolipid-related biological cascades.
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6
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Jiang X, Zhu Z, Qin H, Tripathi P, Zhong L, Elsherbini A, Karki S, Crivelli SM, Zhi W, Wang G, Spassieva SD, Bieberich E. Visualization of Ceramide-Associated Proteins in Ceramide-Rich Platforms Using a Cross-Linkable Ceramide Analog and Proximity Ligation Assays With Anti-ceramide Antibody. Front Cell Dev Biol 2019; 7:166. [PMID: 31475148 PMCID: PMC6706757 DOI: 10.3389/fcell.2019.00166] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/30/2019] [Indexed: 12/20/2022] Open
Abstract
Ceramide-rich platforms (CRPs) mediate association of proteins with the sphingolipid ceramide and may regulate protein interaction in membrane contact sites to the cytoskeleton, organelles, and infectious pathogens. However, visualization of ceramide association to proteins is one of the greatest challenges in understanding the cell biology of ceramide. Here we introduce a novel labeling technique for ceramide-associated proteins (CAPs) by combining photoactivated cross-linking of a bioorthogonal and bifunctional ceramide analog, pacFACer with proximity ligation assays (PLAs). pacFACer cross-linked to CAPs is covalently attached to a fluorophore using click chemistry. PLAs use antibodies to: (1) the candidate CAP and the fluorophore (PLA1); and (2) the CAP and ceramide (PLA2). PLA1 shows the subcellular localization of a particular CAP that is cross-linked to pacFACer, while PLA2 tests if the cross-linked CAP forms a complex with endogenous ceramide. Two proteins, tubulin and voltage-dependent anion channel 1 (VDAC1), were cross-linked to pacFACer and showed PLA signals for a complex with ceramide and pacFACer, which were predominantly colocalized with microtubules and mitochondria, respectively. Binding of tubulin and VDAC1 to ceramide was confirmed by coimmunoprecipitation assays using anti ceramide antibody. Cross-linking to pacFACer was confirmed using click chemistry-mediated attachment of biotin and streptavidin pull-down assays. Inhibition of ceramide synthases with fumonisin B1 (FB1) reduced the degree of pacFACer cross-linking and complex formation with ceramide, while it was enhanced by amyloid beta peptide (Aβ). Our results show that endogenous ceramide is critical for mediating cross-linking of CAPs to pacFACer and that a combination of cross-linking with PLAs (cross-link/PLA) is a novel tool to visualize CAPs and to understand the regulation of protein interaction with ceramide in CRPs.
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Affiliation(s)
- Xue Jiang
- Department of Rehabilitation, ShengJing Hospital of China Medical University, Shenyang, China.,Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Zhihui Zhu
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Haiyan Qin
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Priyanka Tripathi
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Liansheng Zhong
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,College of Life Sciences, China Medical University, Shenyang, China
| | - Ahmed Elsherbini
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Sanjib Karki
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Simone M Crivelli
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Wenbo Zhi
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Guanghu Wang
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | | | - Erhard Bieberich
- Department of Physiology, University of Kentucky, Lexington, KY, United States
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7
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Avota E, de Lira MN, Schneider-Schaulies S. Sphingomyelin Breakdown in T Cells: Role of Membrane Compartmentalization in T Cell Signaling and Interference by a Pathogen. Front Cell Dev Biol 2019; 7:152. [PMID: 31457008 PMCID: PMC6700246 DOI: 10.3389/fcell.2019.00152] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 07/22/2019] [Indexed: 12/15/2022] Open
Abstract
Sphingolipids are major components of cellular membranes, and at steady-state level, their metabolic fluxes are tightly controlled. On challenge by external signals, they undergo rapid turnover, which substantially affects the biophysical properties of membrane lipid and protein compartments and, consequently, signaling and morphodynamics. In T cells, external cues translate into formation of membrane microdomains where proximal signaling platforms essential for metabolic reprograming and cytoskeletal reorganization are organized. This review will focus on sphingomyelinases, which mediate sphingomyelin breakdown and ensuing ceramide release that have been implicated in T-cell viability and function. Acting at the sphingomyelin pool at the extrafacial or cytosolic leaflet of cellular membranes, acid and neutral sphingomyelinases organize ceramide-enriched membrane microdomains that regulate T-cell homeostatic activity and, upon stimulation, compartmentalize receptors, membrane proximal signaling complexes, and cytoskeletal dynamics as essential for initiating T-cell motility and interaction with endothelia and antigen-presenting cells. Prominent examples to be discussed in this review include death receptor family members, integrins, CD3, and CD28 and their associated signalosomes. Progress made with regard to experimental tools has greatly aided our understanding of the role of bioactive sphingolipids in T-cell biology at a molecular level and of targets explored by a model pathogen (measles virus) to specifically interfere with their physiological activity.
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Affiliation(s)
- Elita Avota
- Institute for Virology and Immunobiology, Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Maria Nathalia de Lira
- Institute for Virology and Immunobiology, Julius Maximilian University of Würzburg, Würzburg, Germany
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8
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Collenburg L, Schneider-Schaulies S, Avota E. The neutral sphingomyelinase 2 in T cell receptor signaling and polarity. Biol Chem 2019; 399:1147-1155. [PMID: 29337691 DOI: 10.1515/hsz-2017-0280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/31/2017] [Indexed: 01/13/2023]
Abstract
By hydrolyzing its substrate sphingomyelin at the cytosolic leaflet of cellular membranes, the neutral sphingomyelinase 2 (NSM2) generates microdomains which serve as docking sites for signaling proteins and thereby, functions to regulate signal relay. This has been particularly studied in cellular stress responses while the regulatory role of this enzyme in the immune cell compartment has only recently emerged. In T cells, phenotypic polarization by co-ordinated cytoskeletal remodeling is central to motility and interaction with endothelial or antigen-presenting cells during tissue recruitment or immune synapse formation, respectively. This review highlights studies adressing the role of NSM2 in T cell polarity in which the enzyme plays a major role in regulating cytoskeletal dynamics.
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Affiliation(s)
- Lena Collenburg
- Institute for Virology and Immunobiology, University of Würzburg, Versbacher Str. 7, D-97078 Würzburg, Germany
| | - Sibylle Schneider-Schaulies
- Institute for Virology and Immunobiology, University of Würzburg, Versbacher Str. 7, D-97078 Würzburg, Germany
| | - Elita Avota
- Institute for Virology and Immunobiology, University of Würzburg, Versbacher Str. 7, D-97078 Würzburg, Germany
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9
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Fink J, Seibel J. Click reactions with functional sphingolipids. Biol Chem 2019; 399:1157-1168. [PMID: 29908120 DOI: 10.1515/hsz-2018-0169] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/15/2018] [Indexed: 12/17/2022]
Abstract
Sphingolipids and glycosphingolipids can regulate cell recognition and signalling. Ceramide and sphingosine-1-phosphate are major players in the sphingolipid pathways and are involved in the initiation and regulation of signalling, apoptosis, stress responses and infection. Specific chemically synthesised sphingolipid derivatives containing small functionalities like azide or alkyne can mimic the biological properties of natural lipid species, which turns them into useful tools for the investigation of the highly complex sphingolipid metabolism by rapid and selective 'click chemistry' using sensitive tags like fluorophores. Subsequent analysis by various fluorescence microscopy techniques or mass spectrometry allows the identification and quantification of the corresponding sphingolipid metabolites as well as the research of associated enzymes. Here we present an overview of recent advances in the synthesis of ceramide and sphingosine analogues for bioorthogonal click reactions to study biosynthetic pathways and localization of sphingolipids for the development of novel therapeutics against lipid-dependent diseases.
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Affiliation(s)
- Julian Fink
- University of Würzburg, Institute of Organic Chemistry, Am Hubland, D-97074 Würzburg, Germany
| | - Jürgen Seibel
- University of Würzburg, Institute of Organic Chemistry, Am Hubland, D-97074 Würzburg, Germany
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10
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Bieberich E. Sphingolipids and lipid rafts: Novel concepts and methods of analysis. Chem Phys Lipids 2018; 216:114-131. [PMID: 30194926 PMCID: PMC6196108 DOI: 10.1016/j.chemphyslip.2018.08.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/20/2018] [Accepted: 08/25/2018] [Indexed: 12/12/2022]
Abstract
About twenty years ago, the functional lipid raft model of the plasma membrane was published. It took into account decades of research showing that cellular membranes are not just homogenous mixtures of lipids and proteins. Lateral anisotropy leads to assembly of membrane domains with specific lipid and protein composition regulating vesicular traffic, cell polarity, and cell signaling pathways in a plethora of biological processes. However, what appeared to be a clearly defined entity of clustered raft lipids and proteins became increasingly fluid over the years, and many of the fundamental questions about biogenesis and structure of lipid rafts remained unanswered. Experimental obstacles in visualizing lipids and their interactions hampered progress in understanding just how big rafts are, where and when they are formed, and with which proteins raft lipids interact. In recent years, we have begun to answer some of these questions and sphingolipids may take center stage in re-defining the meaning and functional significance of lipid rafts. In addition to the archetypical cholesterol-sphingomyelin raft with liquid ordered (Lo) phase and the liquid-disordered (Ld) non-raft regions of cellular membranes, a third type of microdomains termed ceramide-rich platforms (CRPs) with gel-like structure has been identified. CRPs are "ceramide rafts" that may offer some fresh view on the membrane mesostructure and answer several critical questions for our understanding of lipid rafts.
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Affiliation(s)
- Erhard Bieberich
- Department of Physiology at the University of Kentucky, Lexington, KY, United States.
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11
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Börtlein C, Draeger A, Schoenauer R, Kuhlemann A, Sauer M, Schneider-Schaulies S, Avota E. The Neutral Sphingomyelinase 2 Is Required to Polarize and Sustain T Cell Receptor Signaling. Front Immunol 2018; 9:815. [PMID: 29720981 PMCID: PMC5915489 DOI: 10.3389/fimmu.2018.00815] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/04/2018] [Indexed: 01/02/2023] Open
Abstract
By promoting ceramide release at the cytosolic membrane leaflet, the neutral sphingomyelinase 2 (NSM) is capable of organizing receptor and signalosome segregation. Its role in T cell receptor (TCR) signaling remained so far unknown. We now show that TCR-driven NSM activation is dispensable for TCR clustering and initial phosphorylation, but of crucial importance for further signal amplification. In particular, at low doses of TCR stimulatory antibodies, NSM is required for Ca2+ mobilization and T cell proliferation. NSM-deficient T cells lack sustained CD3ζ and ZAP-70 phosphorylation and are unable to polarize and stabilize their microtubular system. We identified PKCζ as the key NSM downstream effector in this second wave of TCR signaling supporting dynamics of microtubule-organizing center (MTOC). Ceramide supplementation rescued PKCζ membrane recruitment and MTOC translocation in NSM-deficient cells. These findings identify the NSM as essential in TCR signaling when dynamic cytoskeletal reorganization promotes continued lateral and vertical supply of TCR signaling components: CD3ζ, Zap70, and PKCζ, and functional immune synapses are organized and stabilized via MTOC polarization.
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Affiliation(s)
- Charlene Börtlein
- Institute for Virology and Immunobiology, University of Wuerzburg, Wuerzburg, Germany
| | - Annette Draeger
- Department of Cell Biology, Institute for Anatomy, University of Bern, Bern, Switzerland
| | - Roman Schoenauer
- Department of Cell Biology, Institute for Anatomy, University of Bern, Bern, Switzerland
| | - Alexander Kuhlemann
- Department of Biotechnology and Biophysics, University of Wuerzburg, Wuerzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Wuerzburg, Wuerzburg, Germany
| | | | - Elita Avota
- Institute for Virology and Immunobiology, University of Wuerzburg, Wuerzburg, Germany
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12
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Walter T, Schlegel J, Burgert A, Kurz A, Seibel J, Sauer M. Incorporation studies of clickable ceramides in Jurkat cell plasma membranes. Chem Commun (Camb) 2018; 53:6836-6839. [PMID: 28597878 DOI: 10.1039/c7cc01220a] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The incorporation properties of ceramide analogues for click chemistry in Jurkat T cells were investigated. The analogues varied in the acyl chain length and the position of the functional group for click chemistry. Fluorescence microscopy studies including anisotropy and quenching experiments showed significant differences in the accessibility of the functional group indicating different incorporation properties into the plasma membrane.
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Affiliation(s)
- T Walter
- Institute for Organic Chemistry, Julius-Maximilians University Würzburg, Am Hubland C1, 97074 Würzburg, Germany.
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13
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Bi X, Yin J, Chen Guanbang A, Liu CF. Chemical and Enzymatic Strategies for Bacterial and Mammalian Cell Surface Engineering. Chemistry 2018; 24:8042-8050. [DOI: 10.1002/chem.201705049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Xiaobao Bi
- School of Biological Sciences; Nanyang Technological University; 60 Nanyang Drive Singapore 637551 Singapore
| | - Juan Yin
- Current address: Program in Neuroscience and behavioural disorders; Duke-NUS Medical School; 8 College Road Singapore 169857 Singapore
| | - Ashley Chen Guanbang
- School of Biological Sciences; Nanyang Technological University; 60 Nanyang Drive Singapore 637551 Singapore
| | - Chuan-Fa Liu
- School of Biological Sciences; Nanyang Technological University; 60 Nanyang Drive Singapore 637551 Singapore
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14
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Kong JN, Zhu Z, Itokazu Y, Wang G, Dinkins MB, Zhong L, Lin HP, Elsherbini A, Leanhart S, Jiang X, Qin H, Zhi W, Spassieva SD, Bieberich E. Novel function of ceramide for regulation of mitochondrial ATP release in astrocytes. J Lipid Res 2018; 59:488-506. [PMID: 29321137 DOI: 10.1194/jlr.m081877] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/08/2018] [Indexed: 12/14/2022] Open
Abstract
We reported that amyloid β peptide (Aβ42) activated neutral SMase 2 (nSMase2), thereby increasing the concentration of the sphingolipid ceramide in astrocytes. Here, we show that Aβ42 induced mitochondrial fragmentation in wild-type astrocytes, but not in nSMase2-deficient cells or astrocytes treated with fumonisin B1 (FB1), an inhibitor of ceramide synthases. Unexpectedly, ceramide depletion was concurrent with rapid movements of mitochondria, indicating an unknown function of ceramide for mitochondria. Using immunocytochemistry and super-resolution microscopy, we detected ceramide-enriched and mitochondria-associated membranes (CEMAMs) that were codistributed with microtubules. Interaction of ceramide with tubulin was confirmed by cross-linking to N-[9-(3-pent-4-ynyl-3-H-diazirine-3-yl)-nonanoyl]-D-erythro-sphingosine (pacFACer), a bifunctional ceramide analog, and binding of tubulin to ceramide-linked agarose beads. Ceramide-associated tubulin (CAT) translocated from the perinuclear region to peripheral CEMAMs and mitochondria, which was prevented in nSMase2-deficient or FB1-treated astrocytes. Proximity ligation and coimmunoprecipitation assays showed that ceramide depletion reduced association of tubulin with voltage-dependent anion channel 1 (VDAC1), an interaction known to block mitochondrial ADP/ATP transport. Ceramide-depleted astrocytes contained higher levels of ATP, suggesting that ceramide-induced CAT formation leads to VDAC1 closure, thereby reducing mitochondrial ATP release, and potentially motility and resistance to Aβ42 Our data also indicate that inhibiting ceramide generation may protect mitochondria in Alzheimer's disease.
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Affiliation(s)
- Ji-Na Kong
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Zhihui Zhu
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Yutaka Itokazu
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA
| | - Guanghu Wang
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Michael B Dinkins
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA
| | - Liansheng Zhong
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY.,College of Basic Medicine, China Medical University, Shenyang, People's Republic of China
| | - Hsuan-Pei Lin
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Ahmed Elsherbini
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA.,Department of Physiology, University of Kentucky, Lexington, KY
| | - Silvia Leanhart
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA
| | - Xue Jiang
- Department of Physiology, University of Kentucky, Lexington, KY.,Rehabilitation Center, ShengJing Hospital of China Medical University, Shenyang, People's Republic of China
| | - Haiyan Qin
- Department of Physiology, University of Kentucky, Lexington, KY
| | - Wenbo Zhi
- Center of Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | | | - Erhard Bieberich
- Department of Neuroscience and Regenerative Medicine Augusta University, Augusta, GA .,Department of Physiology, University of Kentucky, Lexington, KY
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Spassieva S, Bieberich E. Lysosphingolipids and sphingolipidoses: Psychosine in Krabbe's disease. J Neurosci Res 2017; 94:974-81. [PMID: 27638582 DOI: 10.1002/jnr.23888] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 07/24/2016] [Accepted: 07/25/2016] [Indexed: 12/14/2022]
Abstract
Until recently, lipids were considered inert building blocks of cellular membranes. This changed three decades ago when lipids were found to regulate cell polarity and vesicle transport, and the "lipid raft" concept took shape. The lipid-driven membrane anisotropy in form of "rafts" that associate with proteins led to the view that organized complexes of lipids and proteins regulate various cell functions. Disturbance of this organization can lead to cellular, tissue, and organ malfunction. Sphingolipidoses, lysosomal storage diseases that are caused by enzyme deficiencies in the sphingolipid degradation pathway, were found to be particularly detrimental to the brain. These enzyme deficiencies result in accumulation of sphingolipid metabolites in lysosomes, although it is not yet clear how this accumulation affects the organization of lipids in cellular membranes. Krabbe's disease (KD), or globoid cell leukodystrophy, was one of the first sphingolipidosis for which the raft concept offered a potential mechanism. KD is caused by mutations in the enzyme β-galactocerebrosidase; however, elevation of its substrate, galactosylceramide, is not observed or considered detrimental. Instead, it was found that a byproduct of galactosylceramide metabolism, the lysosphingolipid psychosine, is accumulated. The "psychosine hypothesis" has been refined by showing that psychosine disrupts lipid rafts and vesicular transport critical for the function of glia and neurons. The role of psychosine in KD is an example of how the disruption of sphingolipid metabolism can lead to elevation of a toxic lysosphingolipid, resulting in disruption of cellular membrane organization and neurotoxicity. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Stefka Spassieva
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, Texas
| | - Erhard Bieberich
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Geogia.
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