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Olesch C, Brüne B, Weigert A. Keep a Little Fire Burning-The Delicate Balance of Targeting Sphingosine-1-Phosphate in Cancer Immunity. Int J Mol Sci 2022; 23:ijms23031289. [PMID: 35163211 PMCID: PMC8836181 DOI: 10.3390/ijms23031289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/21/2022] [Accepted: 01/21/2022] [Indexed: 11/16/2022] Open
Abstract
The sphingolipid sphingosine-1-phosphate (S1P) promotes tumor development through a variety of mechanisms including promoting proliferation, survival, and migration of cancer cells. Moreover, S1P emerged as an important regulator of tumor microenvironmental cell function by modulating, among other mechanisms, tumor angiogenesis. Therefore, S1P was proposed as a target for anti-tumor therapy. The clinical success of current cancer immunotherapy suggests that future anti-tumor therapy needs to consider its impact on the tumor-associated immune system. Hereby, S1P may have divergent effects. On the one hand, S1P gradients control leukocyte trafficking throughout the body, which is clinically exploited to suppress auto-immune reactions. On the other hand, S1P promotes pro-tumor activation of a diverse range of immune cells. In this review, we summarize the current literature describing the role of S1P in tumor-associated immunity, and we discuss strategies for how to target S1P for anti-tumor therapy without causing immune paralysis.
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Affiliation(s)
- Catherine Olesch
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany; (C.O.); (B.B.)
- Bayer Joint Immunotherapeutics Laboratory, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Bernhard Brüne
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany; (C.O.); (B.B.)
- Frankfurt Cancer Institute, Goethe-University Frankfurt, 60596 Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, 60596 Frankfurt, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
| | - Andreas Weigert
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany; (C.O.); (B.B.)
- Frankfurt Cancer Institute, Goethe-University Frankfurt, 60596 Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, 60596 Frankfurt, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
- Correspondence:
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2
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Thomas JM, Sudhadevi T, Basa P, Ha AW, Natarajan V, Harijith A. The Role of Sphingolipid Signaling in Oxidative Lung Injury and Pathogenesis of Bronchopulmonary Dysplasia. Int J Mol Sci 2022; 23:ijms23031254. [PMID: 35163176 PMCID: PMC8835774 DOI: 10.3390/ijms23031254] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
Premature infants are born with developing lungs burdened by surfactant deficiency and a dearth of antioxidant defense systems. Survival rate of such infants has significantly improved due to advances in care involving mechanical ventilation and oxygen supplementation. However, a significant subset of such survivors develops the chronic lung disease, Bronchopulmonary dysplasia (BPD), characterized by enlarged, simplified alveoli and deformed airways. Among a host of factors contributing to the pathogenesis is oxidative damage induced by exposure of the developing lungs to hyperoxia. Recent data indicate that hyperoxia induces aberrant sphingolipid signaling, leading to mitochondrial dysfunction and abnormal reactive oxygen species (ROS) formation (ROS). The role of sphingolipids such as ceramides and sphingosine 1-phosphate (S1P), in the development of BPD emerged in the last decade. Both ceramide and S1P are elevated in tracheal aspirates of premature infants of <32 weeks gestational age developing BPD. This was faithfully reflected in the murine models of hyperoxia and BPD, where there is an increased expression of sphingolipid metabolites both in lung tissue and bronchoalveolar lavage. Treatment of neonatal pups with a sphingosine kinase1 specific inhibitor, PF543, resulted in protection against BPD as neonates, accompanied by improved lung function and reduced airway remodeling as adults. This was accompanied by reduced mitochondrial ROS formation. S1P receptor1 induced by hyperoxia also aggravates BPD, revealing another potential druggable target in this pathway for BPD. In this review we aim to provide a detailed description on the role played by sphingolipid signaling in hyperoxia induced lung injury and BPD.
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Affiliation(s)
- Jaya M. Thomas
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA; (J.M.T.); (T.S.); (P.B.); (A.W.H.)
| | - Tara Sudhadevi
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA; (J.M.T.); (T.S.); (P.B.); (A.W.H.)
| | - Prathima Basa
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA; (J.M.T.); (T.S.); (P.B.); (A.W.H.)
| | - Alison W. Ha
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA; (J.M.T.); (T.S.); (P.B.); (A.W.H.)
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Viswanathan Natarajan
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL 60607, USA;
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Anantha Harijith
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA; (J.M.T.); (T.S.); (P.B.); (A.W.H.)
- Correspondence: ; Tel.: +1-(216)-286-7038
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3
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Abstract
Neuro-inflammation accompanies numerous neurological disorders and conditions where it can be associated with a progressive neurodegenerative pathology. In a similar manner, alterations in sphingolipid metabolism often accompany or are causative features in degenerative neurological conditions. These include dementias, motor disorders, autoimmune conditions, inherited metabolic disorders, viral infection, traumatic brain and spinal cord injury, psychiatric conditions, and more. Sphingolipids are major regulators of cellular fate and function in addition to being important structural components of membranes. Their metabolism and signaling pathways can also be regulated by inflammatory mediators. Therefore, as certain sphingolipids exert distinct and opposing cellular roles, alterations in their metabolism can have major consequences. Recently, regulation of bioactive sphingolipids by neuro-inflammatory mediators has been shown to activate a neuronal NADPH oxidase 2 (NOX2) that can provoke damaging oxidation. Therefore, the sphingolipid-regulated neuronal NOX2 serves as a mechanistic link between neuro-inflammation and neurodegeneration. Moreover, therapeutics directed at sphingolipid metabolism or the sphingolipid-regulated NOX2 have the potential to alleviate neurodegeneration arising out of neuro-inflammation.
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Affiliation(s)
- Emma J Arsenault
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Colin M McGill
- Department of Chemistry, University of Alaska Anchorage, Anchorage, AK, 99508, USA
| | - Brian M Barth
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA.
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4
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Hammerschmidt P, Ostkotte D, Nolte H, Gerl MJ, Jais A, Brunner HL, Sprenger HG, Awazawa M, Nicholls HT, Turpin-Nolan SM, Langer T, Krüger M, Brügger B, Brüning JC. CerS6-Derived Sphingolipids Interact with Mff and Promote Mitochondrial Fragmentation in Obesity. Cell 2020; 177:1536-1552.e23. [PMID: 31150623 DOI: 10.1016/j.cell.2019.05.008] [Citation(s) in RCA: 153] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/26/2019] [Accepted: 05/03/2019] [Indexed: 01/29/2023]
Abstract
Ectopic lipid deposition and altered mitochondrial dynamics contribute to the development of obesity and insulin resistance. However, the mechanistic link between these processes remained unclear. Here we demonstrate that the C16:0 sphingolipid synthesizing ceramide synthases, CerS5 and CerS6, affect distinct sphingolipid pools and that abrogation of CerS6 but not of CerS5 protects from obesity and insulin resistance. We identify proteins that specifically interact with C16:0 sphingolipids derived from CerS5 or CerS6. Here, only CerS6-derived C16:0 sphingolipids bind the mitochondrial fission factor (Mff). CerS6 and Mff deficiency protect from fatty acid-induced mitochondrial fragmentation in vitro, and the two proteins genetically interact in vivo in obesity-induced mitochondrial fragmentation and development of insulin resistance. Our experiments reveal an unprecedented specificity of sphingolipid signaling depending on specific synthesizing enzymes, provide a mechanistic link between hepatic lipid deposition and mitochondrial fragmentation in obesity, and define the CerS6-derived sphingolipid/Mff interaction as a therapeutic target for metabolic diseases.
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Affiliation(s)
- Philipp Hammerschmidt
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne
| | - Daniela Ostkotte
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Hendrik Nolte
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne; Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9B, 50931 Cologne, Germany
| | - Mathias J Gerl
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany; Current address: Lipotype GmbH, Tatzberg 47, 01307 Dresden, Germany
| | - Alexander Jais
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne
| | - Hanna L Brunner
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Hans-Georg Sprenger
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne; Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9B, 50931 Cologne, Germany
| | - Motoharu Awazawa
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne
| | - Hayley T Nicholls
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne
| | - Sarah M Turpin-Nolan
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne
| | - Thomas Langer
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne; Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9B, 50931 Cologne, Germany
| | - Marcus Krüger
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne
| | - Britta Brügger
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Jens C Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne; National Center for Diabetes Research (DZD), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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5
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Abstract
Studies of bioactive lipids in general and sphingolipids in particular have intensified over the past several years, revealing an unprecedented and unanticipated complexity of the lipidome and its many functions, which rivals, if not exceeds, that of the genome or proteome. These results highlight critical roles for bioactive sphingolipids in most, if not all, major cell biological responses, including all major cell signalling pathways, and they link sphingolipid metabolism to key human diseases. Nevertheless, the fairly nascent field of bioactive sphingolipids still faces challenges in its biochemical and molecular underpinnings, including defining the molecular mechanisms of pathway and enzyme regulation, the study of lipid-protein interactions and the development of cellular probes, suitable biomarkers and therapeutic approaches.
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Affiliation(s)
- Yusuf A Hannun
- Stony Brook Cancer Center and Department of Medicine, Stony Brook University, New York 11794, USA
| | - Lina M Obeid
- Stony Brook Cancer Center and Department of Medicine, Stony Brook University, New York 11794, USA
- Northport Veterans Affairs Medical Center, Northport, New York 11768, USA
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6
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Abstract
Hypoxic pulmonary vasoconstriction (HPV) in combination with hypercapnic pulmonary vasoconstriction redistributes pulmonary blood flow from poorly aerated to better ventilated lung regions by an active process of local vasoconstriction. Impairment of HPV results in ventilation-perfusion mismatch and is commonly associated with various lung diseases including pneumonia, sepsis, or cystic fibrosis. Although several regulatory pathways have been identified, considerable knowledge gaps persist, and a unifying concept of the signaling pathways that underlie HPV and their impairment in lung diseases has not yet emerged. In the past, conceptual models of HPV have focused on pulmonary arterial smooth muscle cells (PASMC) acting as sensor and effector of hypoxia in the pulmonary vasculature. In contrast, the endothelium was considered a modulating bystander in this scenario. For an ideal design, however, the oxygen sensor in HPV should be located in the region of gas exchange, i.e., in the alveolar capillary network. This concept requires the retrograde propagation of the hypoxic signal along the endothelial layer of the vascular wall and subsequent contraction of PASMC in upstream arterioles that is elicited via temporospatially tightly controlled endothelial-smooth muscle cell crosstalk. The present review summarizes recent work that provides proof-of-principle for the existence and functional relevance of such signaling pathway in HPV that involves important roles for connexin 40, epoxyeicosatrienoic acids, sphingolipids, and cystic fibrosis transmembrane conductance regulator. Of translational relevance, implication of these molecules provides for novel mechanistic explanations for impaired ventilation/perfusion matching in patients with pneumonia, sepsis, cystic fibrosis, and presumably various other lung diseases.
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Affiliation(s)
- Benjamin Grimmer
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin , Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin , Germany
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Ontario , Canada
- Departments of Surgery and Physiology, University of Toronto , Toronto, Ontario , Canada
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7
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Iqbal J, Walsh MT, Hammad SM, Hussain MM. Sphingolipids and Lipoproteins in Health and Metabolic Disorders. Trends Endocrinol Metab 2017; 28:506-518. [PMID: 28462811 PMCID: PMC5474131 DOI: 10.1016/j.tem.2017.03.005] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 03/09/2017] [Accepted: 03/28/2017] [Indexed: 12/28/2022]
Abstract
Sphingolipids are structurally and functionally diverse molecules with significant physiologic functions and are found associated with cellular membranes and plasma lipoproteins. The cellular and plasma concentrations of sphingolipids are altered in several metabolic disorders and may serve as prognostic and diagnostic markers. Here we discuss various sphingolipid transport mechanisms and highlight how changes in cellular and plasma sphingolipid levels contribute to cardiovascular disease, obesity, diabetes, insulin resistance, and nonalcoholic fatty liver disease (NAFLD). Understanding of the mechanisms involved in intracellular transport, secretion, and extracellular transport may provide novel information that might be amenable to therapeutic targeting for the treatment of various metabolic disorders.
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Affiliation(s)
- Jahangir Iqbal
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, NY 11203, USA; King Abdullah International Medical Research Center, MNGHA, Al Ahsa 31982, Saudi Arabia
| | - Meghan T Walsh
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, NY 11203, USA
| | - Samar M Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - M Mahmood Hussain
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, NY 11203, USA; VA New York Harbor Healthcare System, Brooklyn, New York, NY 11209; Center for Diabetes and Obesity Research, NYU Winthrop Hospital, Mineola, NY 11501, USA.
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8
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Abstract
Sphingolipids are a diverse class of signaling molecules implicated in many important aspects of cellular biology, including growth, differentiation, apoptosis, and autophagy. Autophagy and apoptosis are fundamental physiological processes essential for the maintenance of cellular and tissue homeostasis. There is great interest into the investigation of sphingolipids and their roles in regulating these key physiological processes as well as the manifestation of several disease states. With what is known to date, the entire scope of sphingolipid signaling is too broad, and a single review would hardly scratch the surface. Therefore, this review attempts to highlight the significance of sphingolipids in determining cell fate (e.g. apoptosis, autophagy, cell survival) in the context of the healthy lung, as well as various respiratory diseases including acute lung injury, acute respiratory distress syndrome, bronchopulmonary dysplasia, asthma, chronic obstructive pulmonary disease, emphysema, and cystic fibrosis. We present an overview of the latest findings related to sphingolipids and their metabolites, provide a short introduction to autophagy and apoptosis, and then briefly highlight the regulatory roles of sphingolipid metabolites in switching between cell survival and cell death. Finally, we describe functions of sphingolipids in autophagy and apoptosis in lung homeostasis, especially in the context of the aforementioned diseases.
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Affiliation(s)
- Joyce Lee
- Program in Physiology and Experimental Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
- Institute of Medical Science, University of Toronto, Toronto, ON Canada
| | - Behzad Yeganeh
- Program in Physiology and Experimental Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
| | - Leonardo Ermini
- Program in Physiology and Experimental Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
| | - Martin Post
- Program in Physiology and Experimental Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
- Institute of Medical Science, University of Toronto, Toronto, ON Canada
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9
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Abstract
The regulatory roles of sphingolipids in diverse cell functions have been characterized extensively. However, the dynamics and interactions among the different sphingolipid species are difficult to assess, because de novo biosynthesis, metabolic inter-conversions, and the retrieval of sphingolipids from membranes form a complex, highly regulated pathway system. Here we analyze the heat stress response of this system in the yeast Saccharomyces cerevisiae and demonstrate how the cell dynamically adjusts its enzyme profile so that it is appropriate for operation under stress conditions before changes in gene expression become effective. The analysis uses metabolic time series data, a complex mathematical model, and a custom-tailored optimization strategy. The results demonstrate that all enzyme activities rapidly increase in an immediate response to the elevated temperature. After just a few minutes, different functional clusters of enzymes follow distinct activity patterns. Interestingly, starting after about six minutes, both de novo biosynthesis and all exit routes from central sphingolipid metabolism become blocked, and the remaining metabolic activity consists entirely of an internal redistribution among different sphingoid base and ceramide pools. After about 30 minutes, heat stress is still in effect and the enzyme activity profile is still significantly changed. Importantly, however, the metabolites have regained concentrations that are essentially the same as those under optimal conditions. Sphingolipids play dual roles by serving as components of membrane rafts and by regulating numerous key cell functions. Although sphingolipids have been studied extensively, the details of their functioning are difficult to understand, because their synthesis, pathways of inter-conversion, and utilization constitute a complex, dynamically changing system. We analyze the role of yeast sphingolipids in the response to heat stress. Data show that the profile of these lipids changes almost immediately with the initiation of the stress, but it is a priori unclear how this response is organized. Using experimental data, a sophisticated dynamic model, and a novel optimization strategy, we show how changes in enzyme activities are temporally organized. Intriguingly, the results show that the cells take up as much material as possible in the first few minutes of heat stress and then shut down entry and exit routes of the biosynthetic pathway system. After about 30 minutes, when heat stress is still in effect, the enzyme activity profile is still significantly changed, but the metabolites have regained concentrations that are essentially the same as those under optimal conditions. The results demonstrate how novel insights are achievable with an effective combination of experimental and theoretical research.
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Affiliation(s)
- Po-Wei Chen
- Integrative BioSystems Institute and Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Luis L. Fonseca
- Integrative BioSystems Institute and Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- Instituto de Tecnologia Quıímica e Biológica, Universidade Nova de Lisboa, Estação Agronómica Nacional, Oeiras, Portugal
| | - Yusuf A. Hannun
- The Cancer Center at Stony Brook Medicine, Stony Brook University, Health Science Center, Stony Brook, New York, United States of America
| | - Eberhard O. Voit
- Integrative BioSystems Institute and Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * E-mail:
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10
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Abstract
The atherosclerotic lesion contains a high amount of sphingolipids, a large group of structurally diverse lipids that regulate distinct biological functions beyond their role as structural membrane components. Assessment of their role in atherogenesis has been enabled after genes that regulate their metabolism had been identified and facilitated by the more wide availability of mass spectrometry. Here we discuss recent mechanistic insights obtained in animal and epidemiological studies that have greatly enhanced our understanding of mechanisms how sphingolipids affect the atherosclerotic process.
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Affiliation(s)
- Thorsten Hornemann
- Inst. for Clinical Chemistry, University Hospital Zuerich, Raemistrasse 100, 8091 Zuerich, Switzerland.
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11
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Pimentel AA, Benaim G. [Ca2+ and sphingolipids as modulators for apoptosis and cancer]. Invest Clin 2012; 53:84-110. [PMID: 22524111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Ca2+ is a second messenger which regulates many functions directly related with cancer such as proliferation, differentiation and apoptosis. The intracellular Ca2+ concentration ([Ca2+],) is finely regulated by several mechanisms, among them ionic channels, the endoplasmic reticulum Ca2+-ATPase (SERCA), the plasma membrane calcium pump (PMCA) and the mitochondrial Ca2+ transport. In cancer, the tumour cell proliferates without control since the capacity to recognize apoptotic signals has been lost. The apoptosis is regulated by changes in several proteins, as caspases and the Bcl-2 family members, among others. Additionally, the "reticulum stress", promoted by the accumulation and aggregation of unfolded proteins in the interior of the endoplasmic reticulum (ER), ussually leads to apoptosis. The "reticulum stress" can be induced by several agents, remarkably with thapsigargin, a selective inhibitor of the SERCA, which in turn induces a large increment in [Ca2+],, leading to apoptosis. As a consequence, currently, derivatives of thapsigargin are successfully been assayed as anti-neoplastic agents. Ca2+ is then transferred to the mitochondria, where it is known to constitute a main apoptotic signal. On the other hand, several sphingolipids, such as ceramide and sphingosine, and their phosphorylated derivatives ceramide-1-phosphate and sphingosine-1-phosphate, directly involved in the [Ca2+]1 regulation, are also recognized as signal messengers related with cancer processes. In this review we discuss new evidences on the effect of several sphingolipids in the intracellular Ca2+ homeostasis and its relationship with apoptosis and cancer.
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Affiliation(s)
- Adriana A Pimentel
- Laboratorio de Señialización Celular y Bioquimica de Parásitos Instituto de Estudios Avanzados (IDEA), Carretera Nacional Hoyo de la Puerta, Sartenejas, Baruta
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12
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Permyakov S, Suzina N, Valiakhmetov A. Activation of H+-ATPase of the plasma membrane of Saccharomyces cerevisiae by glucose: the role of sphingolipid and lateral enzyme mobility. PLoS One 2012; 7:e30966. [PMID: 22359558 PMCID: PMC3281057 DOI: 10.1371/journal.pone.0030966] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/30/2011] [Indexed: 11/19/2022] Open
Abstract
Activation of the plasma membrane H(+)-ATPase of the yeast Saccharomyces cerevisiae by glucose is a complex process that has not yet been completely elucidated. This study aimed to shed light on the role of lipids and the lateral mobility of the enzyme complex during its activation by glucose. The significance of H(+)-ATPase oligomerization for the activation of H(+)-ATPase by glucose was shown using the strains lcb1-100 and erg6, with the disturbed synthesis of sphyngolipid and ergosterol, respectively. Experiments with GFP-fused H(+)-ATPase showed a decrease in fluorescence anisotropy during the course of glucose activation, suggesting structural reorganization of the molecular domains. An immunogold assay showed that the incubation with glucose results in the spatial redistribution of ATPase complexes in the plasma membrane. The data suggest that (1) to be activated by glucose, H(+)-ATPase is supposed to be in an oligomeric state, and (2) glucose activation is accompanied by the spatial movements of H(+)-ATPase clusters in the PM.
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Affiliation(s)
- Sergey Permyakov
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Nataliya Suzina
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Airat Valiakhmetov
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
- * E-mail:
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13
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Abstract
Lysosomal lipid storage diseases, or lipidoses, are inherited metabolic disorders in which typically lipids accumulate in cells and tissues. Complex lipids, such as glycosphingolipids, are constitutively degraded within the endolysosomal system by soluble hydrolytic enzymes with the help of lipid binding proteins in a sequential manner. Because of a functionally impaired hydrolase or auxiliary protein, their lipid substrates cannot be degraded, accumulate in the lysosome, and slowly spread to other intracellular membranes. In Niemann-Pick type C disease, cholesterol transport is impaired and unesterified cholesterol accumulates in the late endosome. In most lysosomal lipid storage diseases, the accumulation of one or few lipids leads to the coprecipitation of other hydrophobic substances in the endolysosomal system, such as lipids and proteins, causing a "traffic jam." This can impair lysosomal function, such as delivery of nutrients through the endolysosomal system, leading to a state of cellular starvation. Therapeutic approaches are currently restricted to mild forms of diseases with significant residual catabolic activities and without brain involvement.
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Affiliation(s)
- Heike Schulze
- Life and Medical Sciences Institute, Membrane Biology and Lipid Biochemistry Unit, University of Bonn, Germany
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Liu X, Cheng JC, Turner LS, Elojeimy S, Beckham TH, Bielawska A, Keane TE, Hannun YA, Norris JS. Acid ceramidase upregulation in prostate cancer: role in tumor development and implications for therapy. Expert Opin Ther Targets 2009; 13:1449-58. [PMID: 19874262 PMCID: PMC2796572 DOI: 10.1517/14728220903357512] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Bioactive sphingolipids, such as ceramide, sphingosine and sphingosine-1-phosphate are known bio-effector molecules which play important roles in various aspects of cancer biology including cell proliferation, growth arrest, apoptosis, metastasis, senescence and inflammation. Therefore, enzymes involved in ceramide metabolism are gaining recognition as being critical regulators of cancer cell growth and/or survival. We previously observed that the ceramide metabolizing enzyme, acid ceramidase (AC) is upregulated in tumor tissues. Studies have now concluded that this creates a dysfunctional ceramide pathway, which is responsible for tumor progression and resistance to chemotherapy and radiation. This suggests that development of small-molecule drugs that inhibit AC enzyme activity is a promising approach for improving standard cancer therapy and patient's clinical outcomes.
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Affiliation(s)
- Xiang Liu
- Assistant Professor, Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.7412
| | - Joseph C. Cheng
- MD/PhD Student, Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.8499
| | - Lorianne S. Turner
- Postdoctoral Fellow, Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.8499
| | - Saeed Elojeimy
- Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.814.7010
| | - Thomas H. Beckham
- MD/PhD Student, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.8499
| | - Alicja Bielawska
- Professor, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.1627, Phone: 843.792.0273
| | - Thomas E. Keane
- Professor and Chair, Department of Urology, MUSC, 96 Jonathan Lucas Street, Room 644, Clinical Science Building, Phone: 843.792.1666
| | - Yusuf A. Hannun
- Senior Associate Dean for Basic Sciences, Director, Division of Basic Sciences, Distinguished University Professor, Chair, Department of Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 509, Charleston, South Carolina 29425-5090, FAX: 843.792.4322, Phone: 843.792.9318
| | - James S. Norris
- Professor and Chair, Department of Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.7915
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15
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Abstract
Sphingolipids constitute a biologically active lipid class that is significantly important from both structural and regulatory aspects. The manipulation of sphingolipid metabolism is currently being studied as a novel strategy for cancer therapy. The basics of this therapeutic approach lie in the regulation property of sphingolipids on cellular processes, which are important in a cell's fate, such as cell proliferation, apoptosis, cell cycle arrest, senescence, and inflammation. Furthermore, the mutations in the enzymes catalyzing some specific reactions in the sphingolipid metabolism cause mortal lysosomal storage diseases like Fabry, Gaucher, Niemann-Pick, Farber, Krabbe, and Metachromatic Leukodystrophy. Therefore, the alteration of the sphingolipid metabolic pathway determines the choice between life and death. Understanding the sphingolipid metabolism and regulation is significant for the development of new therapeutic approaches for all sphingolipid-related diseases, as well as for cancer. An important feature of the sphingolipid metabolic pathway is the compartmentalization into endoplasmic reticulum, the Golgi apparatus, lysosome and plasma membrane, and this compartmentalization makes the transport of sphingolipids critical for proper functioning. This paper focuses on the structures, metabolic pathways, localization, transport mechanisms, and diseases of sphingolipids in Saccharomyces cerevisiae and humans, and provides the latest comprehensive information on sphingolipid research.
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16
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Okino N, Ito M. [Structure and functions of bacterial ceramidase]. Seikagaku 2009; 81:911-916. [PMID: 19928534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Nozomu Okino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
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17
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Espinosa Cervantes R. [Sphingolipids in embryonic implantation]. Ginecol Obstet Mex 2009; 77:428-435. [PMID: 19899433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Embryonic implantation is a complex series of processes that establishes the connection between maternal and embryonic tissues and requires an intricate program of uterine preparation. During early gestation in invasively implanting species, the uterine stromal compartment undergoes dramatic remodeling, defined by the differentiation of stromal fibroblast cells into decidual cells. Lipid signaling molecules from a number of pathways are well-established functional components of this decidualization reaction. The decidua provides a vascular network for nutrition and gas exchange for the developing embryo before a functional placenta is established. Because of a correlation in the events that transpire in the uterus during early implantation with known functions of bioactive sphingolipid metabolites established from studies in other organ systems, we hypothesized that uterine sphingolipid metabolism would change during implantation Thus, sphingolipid metabolism regulates proper uterine decidualization and blood vessel stability. The findings also suggest that disturbance in sphingolipid metabolism may be considered as a cause of pregnancy loss in humans.
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Klappe K, Hummel I, Hoekstra D, Kok JW. Lipid dependence of ABC transporter localization and function. Chem Phys Lipids 2009; 161:57-64. [PMID: 19651114 DOI: 10.1016/j.chemphyslip.2009.07.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/24/2009] [Accepted: 07/24/2009] [Indexed: 02/06/2023]
Abstract
Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. ATP-binding cassette (ABC) transporters have also been localized in these membrane domains. In this review the evidence for this specific localization will be evaluated and discussed in terms of relevance to ABC transporter function. We will focus on three ABC transporters of the A, B and C subfamily, respectively. Two of these transporters are relevant to multidrug resistance in tumor cells (Pgp/ABCB1 and MRP1/ABCC1), while the third (ABCA1) is extensively studied in relation to the reverse cholesterol pathway and cellular cholesterol homeostasis. We will attempt to derive a generalized model of lipid rafts to which they associate based on the use of various different lipid raft isolation procedures. In the context of lipid rafts, modulation of ABC transporter localization and function by two relevant lipid classes, i.e. sphingolipids and cholesterol, will be discussed.
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Affiliation(s)
- Karin Klappe
- Department of Cell Biology, Section Membrane Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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Abstract
Recent studies have clearly demonstrated that estrogen signaling is not limited by the canonical 'genomic' pathway. Estrogens have been shown to interact with multiple cytoplasmic signaling networks including that of growth factors, cytokines, and the most recently recognised participants, sphingolipids. Sphingosine kinase (SphK), a key enzyme in metabolic pathways of sphingolipids, plays an important role in cell signaling and regulates a wide range of biological functions, including the actions of estrogens. Herein we briefly review current experimental evidence showing a critical involvement of sphingolipids in estrogen signaling, especially in breast cancer and vascular endothelial cells. In the current review we mainly focus on the SphK pathway and discuss the potential role of SphK and sphingolipids in the cellular biology of estrogens.
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Affiliation(s)
- O Sukocheva
- Division of Human Immunology, Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000, Australia.
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21
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Abstract
The contribution of aberrant production of bioactive lipids to pathophysiological changes associated with obesity has risen to the forefront of lipid research. Increased diacylglycerol has been appreciated as a cause of insulin resistance, but emerging data support a role for sphingolipids in other metabolic diseases including obesity, diabetes, atherosclerosis and metabolic syndrome. Recent data demonstrate that elevation of plasma free fatty acids promotes aberrant sphingolipid production and composition in various tissues including skeletal muscle, pancreas and adipocytes. Moreover, rectifying these aberrant sphingolipid profiles often attenuates pathologies associated with their production. Although data thus far generate more questions than they answer, they indicate a major contribution of sphingolipids to pathologies associated with obesity. This review summarizes recent work in these areas.
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Affiliation(s)
- L Ashley Cowart
- Biochemistry and Molecular Biology, Medical University of South Carolina, 114 Doughty St. Rm 423, Charleston, SC 29401, USA.
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Abstract
This review synthesizes recent insights on the signaling pathways triggered by glucocorticoids during apoptosis of thymocytes. Thymocyte apoptosis is a complex process, which is involved in thymic selection. Even if the main partners are identified, there still remain dark zones on the whole pathway and notably on the crosstalk between each signaling cascade. Glucocorticoids trigger thymocyte apoptosis by enhancing cyclin-dependent kinase 2 activity, downregulating the expression of antiapoptotic Bcl-2 proteins, and upregulating that of proapoptotic Bcl-2 proteins. These events result in mitochondrial alterations and subsequent caspase activation. Proteasome intervenes at various levels of the signaling cascades--for instance, degrading the glucocorticoid receptor or caspase inhibitory proteins. Changes in intracellular K+ and Ca2+ concentrations are involved in caspase and endonulease activation. All these effects are dependent on macromolecular synthesis. The only known non-genomic effect of glucocorticoids is an early production of sphingolipids (ceramide and sphingosine), which are involved in caspase activation independent of mitochondrial alterations. Externalization of phosphatidylserine, a process mediating phagocytosis of dying thymocytes, depends on pathways that diverge from those leading to nuclear apoptosis.
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Affiliation(s)
- Sandrine Lépine
- Biomembranes et Messagers Cellulaires, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8619, Université Paris XI-Orsay, France
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23
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Alewijnse AE, Peters SLM. Sphingolipid signalling in the cardiovascular system: good, bad or both? Eur J Pharmacol 2008; 585:292-302. [PMID: 18420192 DOI: 10.1016/j.ejphar.2008.02.089] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 01/21/2008] [Accepted: 02/06/2008] [Indexed: 12/25/2022]
Abstract
Sphingolipids are biologically active lipids that play important roles in various cellular processes and the sphingomyelin metabolites ceramide, sphingosine and sphingosine-1-phosphate can act as signalling molecules in most cell types. With the recent development of the immunosuppressant drug FTY720 (Fingolimod) which after phosphorylation in vivo acts as a sphingosine-1-phosphate receptor agonist, research on the role of sphingolipids in the immune and other organ systems was triggered enormously. Since it was reported that FTY720 induced a modest, but significant transient decrease in heart rate in animals and humans, the question was raised which pharmacological properties of drugs targeting sphingolipid signalling will affect cardiovascular function in vivo. The answer to this question will most likely also indicate what type of drug could be used to treat cardiovascular disease. The latter is becoming increasingly important because of the increasing population carrying characteristics of the metabolic syndrome. This syndrome is, amongst others, characterized by obesity, hypertension, atherosclerosis and diabetes. As such, individuals with this syndrome are at increased risk of heart disease. Now numerous studies have investigated sphingolipid effects in the cardiovascular system, can we speculate whether certain sphingolipids under specific conditions are good, bad or maybe both? In this review we will give a brief overview of the pathophysiological role of sphingolipids in cardiovascular disease. In addition, we will try to answer how drugs that target sphingolipid signalling will potentially influence cardiovascular function and whether these drugs would be useful to treat cardiovascular disease.
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Affiliation(s)
- Astrid E Alewijnse
- Department of Pharmacology and Pharmacotherapy, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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24
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Abstract
Steroid hormones are essential regulators of a vast number of physiological processes. The biosynthesis of these chemical messengers occurs in specialized steroidogenic tissues via a multi-step process that is catalyzed by members of the cytochrome P450 superfamily of monooxygenases and hydroxysteroid dehydrogenases. Though numerous signaling mediators, including cytokines and growth factors control steroidogenesis, trophic peptide hormones are the primary regulators of steroid hormone production. These peptide hormones activate a cAMP/cAMP-dependent kinase (PKA) signaling pathway, however, studies have shown that crosstalk between multiple signal transduction pathways and signaling molecules modulates optimal steroidogenic capacity. Sphingolipids such as ceramide, sphingosine, sphingosine-1-phosphate, sphingomyelin, and gangliosides have been shown to control the steroid hormone biosynthetic pathway at multiple levels, including regulating steroidogenic gene expression and activity as well as acting as second messengers in signaling cascades. In this review, we provide an overview of recent studies that have investigated the role of sphingolipids in adrenal, gonadal, and neural steroidogenesis.
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Affiliation(s)
- Natasha C Lucki
- School of Biology and Parker H, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332-0230, USA
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25
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Abstract
Sphingolipids, together with phospholipids and cholesterol are key components of membrane lipid bilayers, contribute to specialized membrane domains called rafts and function as signaling molecules. Sphingolipids have been recognized to exert a distinct role in the post-transcriptional regulation of the sterol-regulatory element binding proteins (SREBPs), key transcription factors of lipid synthesis. Sphingolipid synthesis is an obligate activator of SREBP. Inhibition of sphingolipid synthesis decreases SREBP on a post-transcriptional level. With the exception of enzymes that synthesize sphingolipids, SREBPs regulate the transcription of key enzymes that synthesize cholesterol, phospholipids and fatty acids. This observation suggests an exclusive role for sphingolipids in the regulation of lipid metabolism. Although exact mechanisms how sphingolipids regulate lipid metabolism are currently not known, this relationship has important implications with regard to cellular lipid homeostasis, composition of lipoproteins and development of atherosclerosis.
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Affiliation(s)
- Tilla S Worgall
- Department of Pathology, Columbia University, 168 W 168 St, BB 457, New York, NY 10032, USA
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26
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Murate T. [Transcriptional regulation of sphingolipid metabolic enzymes]. Seikagaku 2007; 79:1139-1143. [PMID: 18203454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Takashi Murate
- Nagoya University School of Health Sciences, Daiko Minami 1-1-20, Higashi-ku, Nagoya, 461-8673, Japan
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27
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Abstract
Apoptosis is the regulated form of cell death utilized by metazoans to remove unneeded, damaged, or potentially deleterious cells. Certain manifestations of apoptosis may be associated with the proteolytic activity of caspases. These changes are often held as hallmarks of apoptosis in dying cells. Consequently, many regard caspases as the central effectors or executioners of apoptosis. However, this "caspase-centric" paradigm of apoptotic cell death does not appear to be as universal as once believed. In fact, during apoptosis the efficacy of caspases may be highly dependent on the cytotoxic stimulus as well as genetic and epigenetic factors. An ever-increasing number of studies strongly suggest that there are effectors in addition to caspases, which are important in generating apoptotic signatures in dying cells. These seemingly caspase-independent effectors may represent evolutionarily redundant or failsafe mechanisms for apoptotic cell elimination. In this review, we will discuss the molecular regulation of caspases and various caspase-independent effectors of apoptosis, describe the potential context and/or limitations of these mechanisms, and explore why the understanding of these processes may have relevance in cancer where treatment is believed to engage apoptosis to destroy tumor cells.
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Affiliation(s)
- N Hail
- Department of Clinical Pharmacy, School of Pharmacy, Denver and Health Sciences Center, The University of Colorado, Denver, CO 80262, USA
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28
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Abstract
The new field of membrane rafts has provided fresh insight and a novel framework in which to understand the interaction, relation, and organization of lipids and proteins within cell membranes. This review will examine our current understanding of membrane rafts and their role in human health. In addition, the effect of various lipids, including dietary lipids, on membrane raft structure and function will be discussed. Membrane rafts are found in all cells and are characterized by their high concentration of cholesterol, sphingolipids, and saturated fatty acids. These lipids impart lateral segregation of membrane proteins, thus facilitating the spatial organization and regulation of membrane proteins involved in many cellular processes, such as cell proliferation, apoptosis, and cell signaling. Therefore, membrane rafts are shedding new light on the origins of metabolic disturbances and diseases such as cancer, insulin resistance, inflammation, cardiovascular disease, and Alzheimer's disease, which will be further discussed in this review.
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Affiliation(s)
- David W L Ma
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.
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29
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Abstract
Sphingolipids and glycosphingolipids are emerging as major players in many facets of cell physiology and pathophysiology. We now present an overview of sphingolipid biochemistry and physiology, followed by a brief presentation of recent advances in translational research related to sphingolipids. In discussing sphingolipid biochemistry, we focus on the structure of sphingolipids, and their biosynthetic pathways--the recent identification of most of the enzymes in this pathway has led to significant advances and better characterization of a number of the biosynthetic steps, and the relationship between them. We then discuss some roles of sphingolipids in cell physiology, particularly those of ceramide and sphingosine-1-phosphate, and mention current views about how these lipids act in signal transduction pathways. We end with a discussion of sphingolipids and glycosphingolipids in the etiology and pathology of a number of diseases, such as cancer, immunity, cystic fibrosis, emphysema, diabetes, and sepsis, areas in which sphingolipids are beginning to take a central position, even though many of the details remain to be elucidated.
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Affiliation(s)
- S Lahiri
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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30
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Abstract
This review summarizes data on the role of lysosphingolipids (glucosyl- and galactosylsphingosines, sphingosine-1-phosphate, sphingosine-1-phosphocholine) in the regulation of various biological processes in normal and pathological states.
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Affiliation(s)
- E V Dyatlovitskaya
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 Russia.
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31
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Abstract
Sphingolipids (SLs) comprise a class of lipids with important structural functions and increasing relevance in cellular signalling. In particular, ceramide has attracted considerable attention owing to its role as a second messenger modulating several cell functions such as proliferation, gene expression, differentiation, cell cycle arrest and cell death. Increasing evidence documents the role of SLs in stress and death ligand-induced hepatocellular death, which contributes to the progression of several liver diseases including steatohepatitis, ischaemia-reperfusion liver injury or hepatocarcinogenesis. Furthermore, recent data indicate that the accumulation of SLs in specific cell subcompartments, characteristic of many sphingolipidoses, contributes to the hepatic dysfunctions that accompany these inherited diseases. Hence, the regulation of the cell biology and metabolism of SLs may open up a novel therapeutic avenue in the treatment of liver diseases.
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Affiliation(s)
- Montserrat Marí
- Liver Unit and Centro de Investigaciones Biomédicas Esther Koplowitz, IMDiM, Hospital Clinic i Provincial, CIBER-HEPAD, Instituto Salud Carlos III, IDIBAPS, Barcelona, Spain
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33
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Abstract
Sphingolipids comprise a family of bioactive lipids that exert antagonizing roles in diverse cellular functions such as cell proliferation, growth arrest or apoptosis. Synthesized in the ER/Golgi, sphingolipids are subsequently distributed to different compartments, most predominantly in the plasma membrane, where they integrate signaling platforms. In addition to its precursor role in the synthesis of complex glycosphingolipids, ceramide has been identified as a cell death effector and its generation increases in response to apoptotic stimuli including stress, radiation, chemotherapy, and death ligands. In contrast, sphingosine-1-phosphate (S1P) has been mainly characterized as an antiapoptotic sphingolipid mediating cell proliferation and survival. Thus, the relative balance between ceramide and SIP has important implications in disease pathogenesis, and therefore the pharmacological modulation of enzymes involved in regulation of the ceramide to SIP ratio could constitute a novel therapeutic approach for the treatment of human diseases and cancer.
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Affiliation(s)
- Albert Morales
- Liver Unit, Institut of Malalties Digestives, Hospital Clinic i Provincial, C/ Villarroel 170, 08036-Barcelona, Spain
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Abstract
UNLABELLED The sphingomyelin metabolites ceramide, sphingosine 1-phosphate (S1P) and sphingosylphosphorylcholine (SPC) are emerging modulators of vascular tone. While ceramide appears to act primarily intracellularly, S1P and SPC appear to mainly work via specific receptors, although those for SPC have not yet been defined unequivocally. Each of the sphingomyelin metabolites can induce both vasoconstriction and vasodilatation and, in some cases--ceramide on the one hand, and S1P and SPC on the other hand--have opposite effects on vascular tone. The differences in effects between vessels may relate to the relative roles of endothelial and smooth muscle cells in mediating them, as well as to the distinct expression patterns of S1P receptors among vascular beds and among endothelial and smooth muscle cells. Recent evidence suggests that vascular tone is not only modulated by sphingomyelin metabolites which are exogenously added or reach the vessel wall via the bloodstream but also by those formed locally by cells in the vessel wall. Such local formation can be induced by known vasoactive agents such as angiotensin II and may serve a signalling function. CONCLUSION We conclude that sphingomyelin metabolites are important endogenous modulators of vascular function, which may contribute to the pathophysiology of some diseases and be targets for therapeutic interventions.
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Affiliation(s)
- Martin C Michel
- Department of Pharmacology & Pharmacotherapy, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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35
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Abstract
Sphingolipids are an evolutionary conserved class of membrane lipids synthesized by all eukaryotic cells. The biological functions of sphingolipids are diverse, encompassing structural roles through their participation in membrane lipid rafts, and informational roles via the involvement of their metabolites in signal transduction pathways. An important sphingolipid metabolite is sphingosine-1-phosphate (S1P), which acts through G protein-coupled receptors present on mammalian cells, thereby stimulating cell proliferation, angiogenesis and inhibiting apoptosis. The main enzyme responsible for S1P synthesis, sphingosine kinase 1 (Sphk1), behaves as an oncogene in experimental systems and is required for polyp enlargement in the Min mouse model of intestinal tumorigenesis. S1P is irreversibly degraded by S1P lyase (SPL), an enzyme that is highly expressed in enterocytes, where it is involved in metabolism of dietary sphingolipids. Forced expression of SPL sensitizes human cells to various stressful stimuli and enhances apoptotic cell death. SPL expression is induced in response to DNA damaging agents in a time- and concentration-dependent manner. On the other hand, SPL is downregulated in human colon cancers and in Min mouse adenomas compared to adjacent uninvolved tissues. These observations suggest that SPL, like Sphk1, may play a role in tumorigenesis. Added support for this notion comes from the fact that S1P-specific antibodies slow tumor progression and angiogenesis in murine xenograft and allograft models. Together, these recent studies have established a link between S1P signaling, metabolism and carcinogenesis that may have implications regarding colon cancer screening, dietary chemoprevention and therapeutics.
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Affiliation(s)
- Babak Oskouian
- Children's Hospital Oakland Research Institute, Cancer Center, Oakland, California
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Abstract
The nicotinic acetylcholine receptor (AChR) is the prototype ligand-gated ion channel, and its function is dependent on its lipid environment. In order to study the involvement of sphingolipids (SL) in AChR trafficking, we used pharmacological approaches to dissect the SL biosynthetic pathway in CHO-K1/A5 cells heterologously expressing the muscle-type AChR. When SL biosynthesis was impaired, the cell surface targeting of AChR diminished with a concomitant increase in the intracellular receptor pool. The SL-inhibiting drugs increased unassembled AChR forms, which were retained at the endoplasmic reticulum (ER). These effects on AChR biogenesis and trafficking could be reversed by the addition of exogenous SL, such as sphingomyelin. On the basis of these effects we propose a 'chaperone-like' SL intervention at early stages of the AChR biosynthetic pathway, affecting both the efficiency of the assembly process and subsequent receptor trafficking to the cell surface.
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Affiliation(s)
- C J Baier
- UNESCO Chair of Biophysics and Molecular Neurobiology and Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca, Argentina
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37
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Abstract
PURPOSE OF REVIEW Sphingolipids and their metabolites regulate a great variety of cellular processes. Recent findings implicate sphingolipids in the regulation of lipid synthesis, lipoprotein metabolism and the development of atherosclerosis. RECENT FINDINGS Sphingolipid synthesis correlates with the regulation of the sterol-regulatory element-binding proteins - key transcription factors of genes of lipid metabolism. Inhibition of sphingolipid synthesis decreases synthesis of genes regulated by sterol regulatory element-binding protein, such as the rate-limiting enzymes of fatty acid and cholesterol synthesis as well as fatty-acyl-CoA synthases, important in the synthesis of phospholipids. In animal models, inhibition of sphingolipid synthesis correlates with decreased atherosclerotic lesions and a decreased susceptibility of lipoproteins to aggregate--a key mechanism in the development of the atherosclerotic lesion. The demonstration that ceramide and glucosylceramide (metabolites of sphingolipid synthesis) affect cholesterol efflux and mechanisms that regulate plasma high-density lipoprotein concentrations is further evidence for a role of sphingolipids in the regulation of lipid homeostasis. Direct mechanisms of how sphingolipid synthesis regulates lipid synthesis are currently unknown. The recent identification of key proteins of synthesis and specific transport proteins that regulate sphingolipid synthesis, however, is expected to contribute to the understanding about the interdependent regulation of sphingolipid and lipid metabolism. SUMMARY Emerging data strongly suggest a role of sphingolipid synthesis in the regulation of transcription factors and regulatory proteins that control cellular lipid homeostasis.
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Lavieu G, Scarlatti F, Sala G, Levade T, Ghidoni R, Botti J, Codogno P. Is autophagy the key mechanism by which the sphingolipid rheostat controls the cell fate decision? Autophagy 2007; 3:45-7. [PMID: 17035732 DOI: 10.4161/auto.3416] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Sphingolipids are major constituents of biological membrane and some of them behave as second messengers involved in the cell fate decision. Ceramide and sphingosine 1-phosphate (S1P) constitute a rheostat system in which ceramide promotes cell death and S1P increases cell survival. We have shown that both sphingolipids are able to trigger autophagy with opposing outcomes on cell survival. Here we discuss and speculate on the diverging functions of the autophagic pathways induced by ceramide and S1P, respectively.
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Posse de Chaves EI. Sphingolipids in apoptosis, survival and regeneration in the nervous system. Biochimica et Biophysica Acta (BBA) - Biomembranes 2006; 1758:1995-2015. [PMID: 17084809 DOI: 10.1016/j.bbamem.2006.09.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 09/20/2006] [Accepted: 09/21/2006] [Indexed: 12/27/2022]
Abstract
Simple sphingolipids such as ceramide, sphingosine and sphingosine 1-phosphate are key regulators of diverse cellular functions. Their roles in the nervous system are supported by extensive evidence derived primarily from studies in cultured cells. More recently animal studies and studies with human samples have revealed the importance of ceramide and its metabolites in the development and progression of neurodegenerative disorders. The roles of sphingolipids in neurons and glial cells are complex, cell dependent, and many times contradictory. In this review I will summarize the effects elicited by ceramide and ceramide metabolites in cells of the nervous system, in particular those effects related to cell survival and death, emphasizing the molecular mechanisms involved. I also discuss recent evidence for the implication of sphingolipids in the development and progression of certain dementias.
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Affiliation(s)
- Elena I Posse de Chaves
- Centre for Alzheimer and Neurodegenerative Research, Signal Transduction Research Group and Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
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Krishnamurthy K, Wang G, Silva J, Condie BG, Bieberich E. Ceramide regulates atypical PKCzeta/lambda-mediated cell polarity in primitive ectoderm cells. A novel function of sphingolipids in morphogenesis. J Biol Chem 2006; 282:3379-90. [PMID: 17105725 DOI: 10.1074/jbc.m607779200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In mammals, the primitive ectoderm is an epithelium of polarized cells that differentiates into all embryonic tissues. Our study shows that in primitive ectoderm cells, the sphingolipid ceramide was elevated and co-distributed with the small GTPase Cdc42 and cortical F-actin at the apicolateral cell membrane. Pharmacological or RNA interference-mediated inhibition of ceramide biosynthesis enhanced apoptosis and impaired primitive ectoderm formation in embryoid bodies differentiated from mouse embryonic stem cells. Primitive ectoderm formation was restored by incubation with ceramide or a ceramide analog. Ceramide depletion prevented plasma membrane translocation of PKCzeta/lambda, its interaction with Cdc42, and phosphorylation of GSK-3beta, a substrate of PKCzeta/lambda. Recombinant PKCzeta formed a complex with the polarity protein Par6 and Cdc42 when bound to ceramide containing lipid vesicles. Our data suggest a novel mechanism by which a ceramide-induced, apicolateral polarity complex with PKCzeta/lambda regulates primitive ectoderm cell polarity and morphogenesis.
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Affiliation(s)
- Kannan Krishnamurthy
- Institute of Molecular Medicine and Genetics, School of Medicine, Medical College of Georgia, Augusta, Georgia 30912, USA
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Daquinag A, Fadri M, Jung SY, Qin J, Kunz J. The yeast PH domain proteins Slm1 and Slm2 are targets of sphingolipid signaling during the response to heat stress. Mol Cell Biol 2006; 27:633-50. [PMID: 17101780 PMCID: PMC1800798 DOI: 10.1128/mcb.00461-06] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The PH domain-containing proteins Slm1 and Slm2 were previously identified as effectors of the phosphatidylinositol-4,5-bisphosphate (PI4,5P(2)) and TORC2 signaling pathways. Here, we demonstrate that Slm1 and Slm2 are also targets of sphingolipid signaling during the heat shock response. We show that upon depletion of cellular sphingolipid levels, Slm1 function becomes essential for survival under heat stress. We further demonstrate that Slm proteins are regulated by a phosphorylation/dephosphorylation cycle involving the sphingolipid-activated protein kinases Pkh1 and Pkh2 and the calcium/calmodulin-dependent protein phosphatase calcineurin. By using a combination of mass spectrometry and mutational analysis, we identified serine residue 659 in Slm1 as a site of phosphorylation. Characterization of Slm1 mutants that mimic dephosphorylated and phosphorylated states demonstrated that phosphorylation at serine 659 is vital for survival under heat stress and promotes the proper polarization of the actin cytoskeleton. Finally, we present evidence that Slm proteins are also required for the trafficking of the raft-associated arginine permease Can1 to the plasma membrane, a process that requires sphingolipid synthesis and actin polymerization. Together with previous work, our findings suggest that Slm proteins are subject to regulation by multiple signals, including PI4,5P(2), TORC2, and sphingolipids, and may thus integrate inputs from different signaling pathways to temporally and spatially control actin polarization.
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Affiliation(s)
- Alexes Daquinag
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX 77030, USA
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Abstract
Lipid rafts are liquid ordered membrane domains enriched with sphingolipids and cholesterol. After 20 years since the proposal of the original concept, the structure and function of lipid rafts are still obscure. Recently new tools to study lipid rafts have been developed. Lysenin is a sphingomyelin binding protein that specifically recognizes the lipid clusters. Poly(ethyleneglycol)-derivatized cholesterol ether (PEG-Chol) is a non-toxic cholesterol probe. These probes have revealed the heterogeneity of lipid rafts. The heterogeneity of lipid rafts is further supported by the discovery of a new lipid component, phosphatidylglucoside. Metabolic inhibitors are another useful tool. Sulfamisterin is a new addition to the serine palmitoyltransferase inhibitors. Recent findings have uncovered a previously unrecognized activity of a glycosphingolipid synthesis inhibitor, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP).
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Affiliation(s)
- Toshihide Kobayashi
- Lipid Biology Laboratory, RIKEN (Institute of Physical and Chemical Research), Japan.
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Gaigg B, Toulmay A, Schneiter R. Very long-chain fatty acid-containing lipids rather than sphingolipids per se are required for raft association and stable surface transport of newly synthesized plasma membrane ATPase in yeast. J Biol Chem 2006; 281:34135-45. [PMID: 16980694 DOI: 10.1074/jbc.m603791200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The proton-pumping H+-ATPase, Pma1p, is an abundant and very long lived polytopic protein of the yeast plasma membrane. Pma1p constitutes a major cargo of the secretory pathway and thus serves as a model to study plasma membrane biogenesis. Pma1p associates with detergent-resistant membrane domains (lipid "rafts") already in the ER, and a lack of raft association correlates with mistargeting of the protein to the vacuole, where it is degraded. We are analyzing the role of specific lipids in membrane domain formation and have previously shown that surface transport of Pma1p is independent of newly synthesized sterols but that sphingolipids with C26 very long chain fatty acid are crucial for raft association and surface transport of Pma1p (Gaigg, B., Timischl, B., Corbino, L., and Schneiter, R. (2005) J. Biol. Chem. 280, 22515-22522). We now describe a more detailed analysis of the function that sphingolipids play in this process. Using a yeast strain in which the essential function of sphingolipids is substituted by glycerophospholipids containing C26 very long chain fatty acids, we find that sphingolipids per se are dispensable for raft association and surface delivery of Pma1p but that the C26 fatty acid is crucial. We thus conclude that the essential function of sphingolipids for membrane domain formation and stable surface delivery of Pma1p is provided by the C26 fatty acid that forms part of the yeast ceramide.
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Affiliation(s)
- Barbara Gaigg
- Division of Biochemistry, University of Fribourg, CH-1700 Fribourg, Switzerland
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Zheng W, Kollmeyer J, Symolon H, Momin A, Munter E, Wang E, Kelly S, Allegood JC, Liu Y, Peng Q, Ramaraju H, Sullards MC, Cabot M, Merrill AH. Ceramides and other bioactive sphingolipid backbones in health and disease: lipidomic analysis, metabolism and roles in membrane structure, dynamics, signaling and autophagy. Biochim Biophys Acta 2006; 1758:1864-84. [PMID: 17052686 DOI: 10.1016/j.bbamem.2006.08.009] [Citation(s) in RCA: 408] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 08/16/2006] [Indexed: 12/14/2022]
Abstract
Sphingolipids are comprised of a backbone sphingoid base that may be phosphorylated, acylated, glycosylated, bridged to various headgroups through phosphodiester linkages, or otherwise modified. Organisms usually contain large numbers of sphingolipid subspecies and knowledge about the types and amounts is imperative because they influence membrane structure, interactions with the extracellular matrix and neighboring cells, vesicular traffic and the formation of specialized structures such as phagosomes and autophagosomes, as well as participate in intracellular and extracellular signaling. Fortunately, "sphingolipidomic" analysis is becoming feasible (at least for important subsets such as all of the backbone "signaling" subspecies: ceramides, ceramide 1-phosphates, sphingoid bases, sphingoid base 1-phosphates, inter alia) using mass spectrometry, and these profiles are revealing many surprises, such as that under certain conditions cells contain significant amounts of "unusual" species: N-mono-, di-, and tri-methyl-sphingoid bases (including N,N-dimethylsphingosine); 3-ketodihydroceramides; N-acetyl-sphingoid bases (C2-ceramides); and dihydroceramides, in the latter case, in very high proportions when cells are treated with the anticancer drug fenretinide (4-hydroxyphenylretinamide). The elevation of DHceramides by fenretinide is befuddling because the 4,5-trans-double bond of ceramide has been thought to be required for biological activity; however, DHceramides induce autophagy and may be important in the regulation of this important cellular process. The complexity of the sphingolipidome is hard to imagine, but one hopes that, when partnered with other systems biology approaches, the causes and consequences of the complexity will explain how these intriguing compounds are involved in almost every aspect of cell behavior and the malfunctions of many diseases.
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Affiliation(s)
- Wenjing Zheng
- School of Biology, Chemistry and Biochemistry, Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA
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Abstract
Sphingolipids are important signalling molecules and thus it is very important to understand how they are generated. Sphingolipid biosynthesis shows a conserved compartmentalization in eukaryotic cells. Their synthesis begins in the endoplasmic reticulum and is completed in the Golgi apparatus. We now know quite a bit about the topology of the reactions in the pathway, but certain critical steps, such as ceramide synthesis, are still poorly understood. In the present paper, we discuss the latest views on this subject.
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Affiliation(s)
- H Riezman
- Department of Biochemistry, University of Geneva, Switzerland.
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Cowart LA, Obeid LM. Yeast sphingolipids: recent developments in understanding biosynthesis, regulation, and function. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1771:421-31. [PMID: 16997623 PMCID: PMC1868558 DOI: 10.1016/j.bbalip.2006.08.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 08/02/2006] [Accepted: 08/03/2006] [Indexed: 01/28/2023]
Abstract
Sphingolipids function as required membrane components of virtually all eukaryotic cells. Data indicate that members of the sphingolipid family of lipids, including sphingoid bases, sphingoid base phosphates, ceramides, and complex sphingolipids, serve vital functions in cell biology by both direct mechanisms (e.g., binding to G-protein coupled receptors to transduce an extracellular signal) and indirect mechanisms (e.g., facilitating correct intracellular protein transport). Because of the diverse roles these lipids play in cell biology, it is important to understand not only their biosynthetic pathways and regulation of sphingolipid synthesis, but also the mechanisms by which some sphingolipid species with specific functions are modified or converted to other sphingolipid species with alternate functions. Due to many factors including ease of culture and genetic modification, and conservation of major sphingolipid metabolic pathways, Saccharomyces cerevisiae has served as an ideal model system with which to identify enzymes of sphingolipid biosynthesis and to dissect sphingolipid function. Recent exciting developments in sphingolipid synthesis, transport, signaling, and overall biology continue to fuel vigorous investigation and inspire investigations in mammalian sphingolipid biology.
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Affiliation(s)
- L Ashley Cowart
- Research Service, Department of Veterans Affairs Medical Center, Charleston, SC 29425, USA
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Snook CF, Jones JA, Hannun YA. Sphingolipid-binding proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:927-46. [PMID: 16901751 DOI: 10.1016/j.bbalip.2006.06.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 06/20/2006] [Accepted: 06/27/2006] [Indexed: 11/21/2022]
Abstract
Emerging information on sphingolipid metabolism and signaling is leading to a better understanding of cellular processes such as apoptosis, cancer, cell survival and aging. In this review, we discuss the involvement of sphingolipids in these processes and focus on underlying mechanisms based on sphingolipid:protein interactions. Due to the inherent difficulty of studying lipids, we discuss techniques that are useful in the elucidation of these interactions. We classify sphingolipid-binding proteins into four main classes: receptor, effector, enzyme, and transporter. Known structures of sphingolipid-binding proteins are surveyed, and sphingolipid-binding characteristics are described, acknowledging the limitations that there are presently insufficient protein:sphingolipid complexes for more definitive conclusions on this topic. Finally we summarize relevant literature to better inform the reader about sphingolipid:protein interactions.
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Affiliation(s)
- C F Snook
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA.
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Abstract
The era of sphingolipid-based therapeutics is upon us. A large body of work has been accumulating that demonstrates the distinct biological roles of sphingolipids in maintaining a homeostatic environment and in responding to environmental stimuli to regulate cellular processes. It is thus necessary to further investigate alterations in sphingolipid-metabolism in pathological conditions and, in turn, try to exploit altered sphingolipid-metabolizing enzymes and their metabolites as therapeutic targets. This review will examine how advances in the fields of drug delivery, drug discovery, synthetic chemistry, enzyme replacement therapy, immunobiology, infectious disease and nanotechnology have delivered the potential and promise of utilizing and/or targeting sphingolipid metabolites as therapies for diverse diseases.
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Affiliation(s)
- T E Fox
- Department of Pharmacology, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
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