1
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Merz N, Hartel JC, Grösch S. How ceramides affect the development of colon cancer: from normal colon to carcinoma. Pflugers Arch 2024:10.1007/s00424-024-02960-x. [PMID: 38635059 DOI: 10.1007/s00424-024-02960-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/16/2024] [Accepted: 04/03/2024] [Indexed: 04/19/2024]
Abstract
The integrity of the colon and the development of colon cancer depend on the sphingolipid balance in colon epithelial cells. In this review, we summarize the current knowledge on how ceramides and their complex derivatives influence normal colon development and colon cancer development. Ceramides, glucosylceramides and sphingomyelin are essential membrane components and, due to their biophysical properties, can influence the activation of membrane proteins, affecting protein-protein interactions and downstream signalling pathways. Here, we review the cellular mechanisms known to be affected by ceramides and their effects on colon development. We also describe which ceramides are deregulated during colorectal carcinogenesis, the molecular mechanisms involved in ceramide deregulation and how this affects carcinogenesis. Finally, we review new methods that are now state of the art for studying lipid-protein interactions in the physiological environment.
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Affiliation(s)
- Nadine Merz
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Theodor Stern Kai 7, 60590, Frankfurt, Germany
| | - Jennifer Christina Hartel
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Theodor Stern Kai 7, 60590, Frankfurt, Germany
| | - Sabine Grösch
- Goethe-University Frankfurt, Institute of Clinical Pharmacology, Theodor Stern Kai 7, 60590, Frankfurt, Germany.
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596, Frankfurt Am Main, Germany.
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2
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Jamjoum R, Majumder S, Issleny B, Stiban J. Mysterious sphingolipids: metabolic interrelationships at the center of pathophysiology. Front Physiol 2024; 14:1229108. [PMID: 38235387 PMCID: PMC10791800 DOI: 10.3389/fphys.2023.1229108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 11/27/2023] [Indexed: 01/19/2024] Open
Abstract
Metabolic pathways are complex and intertwined. Deficiencies in one or more enzymes in a given pathway are directly linked with genetic diseases, most of them having devastating manifestations. The metabolic pathways undertaken by sphingolipids are diverse and elaborate with ceramide species serving as the hubs of sphingolipid intermediary metabolism and function. Sphingolipids are bioactive lipids that serve a multitude of cellular functions. Being pleiotropic in function, deficiency or overproduction of certain sphingolipids is associated with many genetic and chronic diseases. In this up-to-date review article, we strive to gather recent scientific evidence about sphingolipid metabolism, its enzymes, and regulation. We shed light on the importance of sphingolipid metabolism in a variety of genetic diseases and in nervous and immune system ailments. This is a comprehensive review of the state of the field of sphingolipid biochemistry.
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Affiliation(s)
- Rama Jamjoum
- Department of Pharmacy, Birzeit University, West Bank, Palestine
| | - Saurav Majumder
- National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Rockville, MD, United States
| | - Batoul Issleny
- Department of Pharmacy, Birzeit University, West Bank, Palestine
| | - Johnny Stiban
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine
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3
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Issleny BM, Jamjoum R, Majumder S, Stiban J. Sphingolipids: From structural components to signaling hubs. Enzymes 2023; 54:171-201. [PMID: 37945171 DOI: 10.1016/bs.enz.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
In late November 2019, Prof. Lina M. Obeid passed away from cancer, a disease she spent her life researching and studying its intricate molecular underpinnings. Along with her husband, Prof. Yusuf A. Hannun, Obeid laid down the foundations of sphingolipid biochemistry and oversaw its remarkable evolution over the years. Lipids are a class of macromolecules that are primarily associated with cellular architecture. In fact, lipids constitute the perimeter of the cell in such a way that without them, there cannot be cells. Hence, much of the early research on lipids identified the function of this class of biological molecules as merely structural. Nevertheless, unlike proteins, carbohydrates, and nucleic acids, lipids are elaborately diverse as they are not made up of monomers in polymeric forms. This diversity in structure is clearly mirrored by functional pleiotropy. In this chapter, we focus on a major subset of lipids, sphingolipids, and explore their historic rise from merely inert structural components of plasma membranes to lively and necessary signaling molecules that transmit various signals and control many cellular processes. We will emphasize the works of Lina Obeid since she was an integral pillar of the sphingolipid research world.
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Affiliation(s)
- Batoul M Issleny
- Department of Pharmacy, Birzeit University, West Bank, Palestine
| | - Rama Jamjoum
- Department of Pharmacy, Birzeit University, West Bank, Palestine
| | | | - Johnny Stiban
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine.
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4
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Cross-Regulation of the Cellular Redox System, Oxygen, and Sphingolipid Signalling. Metabolites 2023; 13:metabo13030426. [PMID: 36984866 PMCID: PMC10054022 DOI: 10.3390/metabo13030426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
Redox-active mediators are now appreciated as powerful molecules to regulate cellular dynamics such as viability, proliferation, migration, cell contraction, and relaxation, as well as gene expression under physiological and pathophysiological conditions. These molecules include the various reactive oxygen species (ROS), and the gasotransmitters nitric oxide (NO∙), carbon monoxide (CO), and hydrogen sulfide (H2S). For each of these molecules, direct targets have been identified which transmit the signal from the cellular redox state to a cellular response. Besides these redox mediators, various sphingolipid species have turned out as highly bioactive with strong signalling potential. Recent data suggest that there is a cross-regulation existing between the redox mediators and sphingolipid molecules that have a fundamental impact on a cell’s fate and organ function. This review will summarize the effects of the different redox-active mediators on sphingolipid signalling and metabolism, and the impact of this cross-talk on pathophysiological processes. The relevance of therapeutic approaches will be highlighted.
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5
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Santos TCB, Dingjan T, Futerman AH. The sphingolipid anteome: implications for evolution of the sphingolipid metabolic pathway. FEBS Lett 2022; 596:2345-2363. [PMID: 35899376 DOI: 10.1002/1873-3468.14457] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/10/2022] [Accepted: 07/19/2022] [Indexed: 11/09/2022]
Abstract
Modern cell membranes contain a bewildering complexity of lipids, among them sphingolipids (SLs). Advances in mass spectrometry have led to the realization that the number and combinatorial complexity of lipids, including SLs, is much greater than previously appreciated. SLs are generated de novo by four enzymes, namely serine palmitoyltransferase, 3-ketodihydrosphingosine reductase, ceramide synthase and dihydroceramide Δ4-desaturase 1. Some of these enzymes depend on the availability of specific substrates and cofactors, which are themselves supplied by other complex metabolic pathways. The evolution of these four enzymes is poorly understood and likely depends on the co-evolution of the metabolic pathways that supply the other essential reaction components. Here, we introduce the concept of the 'anteome', from the Latin ante ('before') to describe the network of metabolic ('omic') pathways that must have converged in order for these pathways to co-evolve and permit SL synthesis. We also suggest that current origin of life and evolutionary models lack appropriate experimental support to explain the appearance of this complex metabolic pathway and its anteome.
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Affiliation(s)
- Tania C B Santos
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Tamir Dingjan
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
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6
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Farkas Á, Urlaub H, Bohnsack KE, Schwappach B. Regulated targeting of the monotopic hairpin membrane protein Erg1 requires the GET pathway. J Biophys Biochem Cytol 2022; 221:213228. [PMID: 35587358 PMCID: PMC9123286 DOI: 10.1083/jcb.202201036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/27/2022] [Accepted: 04/12/2022] [Indexed: 02/08/2023] Open
Abstract
The guided entry of tail-anchored proteins (GET) pathway targets C-terminally anchored transmembrane proteins and protects cells from lipotoxicity. Here, we reveal perturbed ergosterol production in ∆get3 cells and demonstrate the sensitivity of GET pathway mutants to the sterol synthesis inhibiting drug terbinafine. Our data uncover a key enzyme of sterol synthesis, the hairpin membrane protein squalene monooxygenase (Erg1), as a non-canonical GET pathway client, thus rationalizing the lipotoxicity phenotypes of GET pathway mutants. Get3 recognizes the hairpin targeting element of Erg1 via its classical client-binding pocket. Intriguingly, we find that the GET pathway is especially important for the acute upregulation of Erg1 induced by low sterol conditions. We further identify several other proteins anchored to the endoplasmic reticulum (ER) membrane exclusively via a hairpin as putative clients of the GET pathway. Our findings emphasize the necessity of dedicated targeting pathways for high-efficiency targeting of particular clients during dynamic cellular adaptation and highlight hairpin proteins as a potential novel class of GET clients.
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Affiliation(s)
- Ákos Farkas
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytic Mass Spectrometry, Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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7
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Pilz R, Opálka L, Majcher A, Grimm E, Van Maldergem L, Mihalceanu S, Schäkel K, Enk A, Aubin F, Bursztejn AC, Brischoux-Boucher E, Fischer J, Sandhoff R. Formation of keto-type ceramides in palmoplantar keratoderma based on biallelic KDSR mutations in patients. Hum Mol Genet 2021; 31:1105-1114. [PMID: 34686882 DOI: 10.1093/hmg/ddab309] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 11/14/2022] Open
Abstract
Functional skin barrier requires sphingolipid homeostasis. 3-ketodihydrosphingosine reductase or KDSR is a key enzyme of sphingolipid anabolism catalyzing the reduction of 3-ketodihydrosphingosine to sphinganine. Biallelic mutations in the KDSR gene may cause erythrokeratoderma variabilis et progressive-4, later specified as PERIOPTER syndrome, emphasizing a characteristic periorifical and ptychotropic erythrokeratoderma. We report another patient with compound heterozygous mutations in KDSR, born with generalized harlequin ichthyosis, which progressed into palmoplantar keratoderma. To determine whether patient-associated KDSR mutations lead to KDSR substrate accumulation and/or unrecognized sphingolipid downstream products in stratum corneum we analyzed lipids of this and previously published patients with non-identical biallelic mutations in KDSR. In stratum corneum of both patients we identified hitherto unobserved skin ceramides with an unusual keto-type sphingoid base in lesional and non-lesional areas, which accounted for up to 10% of the measured ceramide species. Furthermore, an overall shorter mean chain length of free and bound sphingoid bases was observed-shorter mean chain length of free sphingoid bases was also observed in lesional psoriasis vulgaris SC, but not generally in lesional atopic dermatitis SC. Formation of keto-type ceramides is probably due to a bottle neck in metabolic flux through KDSR and a bypass by ceramide synthases, which highlights the importance of tight intermediate regulation during sphingolipid anabolism and reveals substrate deprivation as potential therapy.
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Affiliation(s)
- Robert Pilz
- Lipid Pathobiochemistry Group, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Lukáš Opálka
- Lipid Pathobiochemistry Group, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Skin Barrier Research Group, Department of Organic and Bioorganic Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic
| | - Adam Majcher
- Lipid Pathobiochemistry Group, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Skin Barrier Research Group, Department of Organic and Bioorganic Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czech Republic
| | - Elisabeth Grimm
- Lipid Pathobiochemistry Group, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Lionel Van Maldergem
- Centre de Génétique Humaine, Université de Franche-Comté, 25000, Besançon, France.,Clinical Investigation Center 1431, National Institute of Health and Medical Research (INSERM), University Hospital, 25000, Besançon, France
| | - Silvia Mihalceanu
- Department of Dermatology, Medical Faculty of the University of Heidelberg, 69120, Heidelberg, Germany
| | - Knut Schäkel
- Department of Dermatology, Medical Faculty of the University of Heidelberg, 69120, Heidelberg, Germany
| | - Alexander Enk
- Department of Dermatology, Medical Faculty of the University of Heidelberg, 69120, Heidelberg, Germany
| | - François Aubin
- Service de Dermatologie et INSERM 1098 RIGHT, CHU et UFR Santé, 25000, Besançon France
| | | | | | - Judith Fischer
- Institute of Human Genetics, Medical Center, Faculty of Medicine, University of Freiburg, 79106, Freiburg im Breisgau, Germany
| | - Roger Sandhoff
- Lipid Pathobiochemistry Group, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
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8
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Fernandes CM, Poeta MD. Fungal sphingolipids: role in the regulation of virulence and potential as targets for future antifungal therapies. Expert Rev Anti Infect Ther 2020; 18:1083-1092. [PMID: 32673125 PMCID: PMC7657966 DOI: 10.1080/14787210.2020.1792288] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The antifungal therapy currently available includes three major classes of drugs: polyenes, azoles and echinocandins. However, the clinical use of these compounds faces several challenges: while polyenes are toxic to the host, antifungal resistance to azoles and echinocandins has been reported. AREAS COVERED Fungal sphingolipids (SL) play a pivotal role in growth, morphogenesis and virulence. In addition, fungi possess unique enzymes involved in SL synthesis, leading to the production of lipids which are absent or differ structurally from the mammalian counterparts. In this review, we address the enzymatic reactions involved in the SL synthesis and their relevance to the fungal pathogenesis, highlighting their potential as targets for novel drugs and the inhibitors described so far. EXPERT OPINION The pharmacological inhibition of fungal serine palmitoyltransferase depends on the development of specific drugs, as myriocin also targets the mammalian enzyme. Inhibitors of ceramide synthase might constitute potent antifungals, by depleting the pool of complex SL and leading to the accumulation of the toxic intermediates. Acylhydrazones and aureobasidin A, which inhibit GlcCer and IPC synthesis, are not toxic to the host and effectively treat invasive mycoses, emerging as promising new classes of antifungal drugs.
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Affiliation(s)
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, NY, USA
- Division of Infectious Diseases, School of Medicine, Stony Brook University, NY, USA
- Veterans Administration Medical Center, Northport, NY, USA
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9
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Huber M, Chiticariu E, Bachmann D, Flatz L, Hohl D. Palmoplantar Keratoderma with Leukokeratosis Anogenitalis Caused by KDSR Mutations. J Invest Dermatol 2020; 140:1662-1665.e1. [PMID: 31987885 DOI: 10.1016/j.jid.2019.11.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 11/01/2019] [Accepted: 11/11/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Marcel Huber
- Service of Dermatology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Elena Chiticariu
- Service of Dermatology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Daniel Bachmann
- Service of Dermatology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Lukas Flatz
- Institute for Immune Biology, St. Gallen Cantonal Hospital, St. Gallen, Switzerland
| | - Daniel Hohl
- Service of Dermatology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
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10
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Han G, Gupta SD, Gable K, Bacikova D, Sengupta N, Somashekarappa N, Proia RL, Harmon JM, Dunn TM. The ORMs interact with transmembrane domain 1 of Lcb1 and regulate serine palmitoyltransferase oligomerization, activity and localization. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:245-259. [PMID: 30529276 DOI: 10.1016/j.bbalip.2018.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/30/2018] [Accepted: 11/24/2018] [Indexed: 10/27/2022]
Abstract
Serine palmitoyltransferase (SPT), an endoplasmic reticulum-localized membrane enzymecomposed of acatalytic LCB1/LCB2 heterodimer and a small activating subunit (Tsc3 in yeast; ssSPTs in mammals), is negatively regulated by the evolutionarily conserved family of proteins known as the ORMs. In yeast, SPT, the ORMs, and the PI4P phosphatase Sac1, copurify in the "SPOTs" complex. However, neither the mechanism of ORM inhibition of SPT nor details of the interactions of the ORMs and Sac1 with SPT are known. Here we report that the first transmembrane domain (TMD1) of Lcb1 is required for ORM binding to SPT. Loss of binding is not due to altered membrane topology of Lcb1 since replacing TMD1 with a heterologous TMD restores membrane topology but not ORM binding. TMD1 deletion also eliminates ORM-dependent formation of SPT oligomers as assessed by co-immunoprecipitation assays and in vivo imaging. Expression of ORMs lacking derepressive phosphorylation sites results in constitutive SPT oligomerization, while phosphomimetic ORMs fail to induce oligomerization under any conditions. Significantly, when LCB1-RFP and LCB1ΔTMD1-GFP were coexpressed, more LCB1ΔTMD1-GFP was in the peripheral ER, suggesting ORM regulation is partially accomplished by SPT redistribution. Tsc3 deletion does not abolish ORM inhibition of SPT, indicating the ORMs do not simply prevent activation by Tsc3. Binding of Sac1 to SPT requires Tsc3, but not the ORMs, and Sac1 does not influence ORM-mediated oligomerization of SPT. Finally, yeast mutants lacking ORM regulation of SPT require the LCB-P lyase Dpl1 to maintain long-chain bases at sublethal levels.
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Affiliation(s)
- Gongshe Han
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Sita D Gupta
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Kenneth Gable
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Dagmar Bacikova
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Nivedita Sengupta
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Niranjanakumari Somashekarappa
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Richard L Proia
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, United States of America
| | - Jeffrey M Harmon
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States of America.
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11
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Bariana TK, Labarque V, Heremans J, Thys C, De Reys M, Greene D, Jenkins B, Grassi L, Seyres D, Burden F, Whitehorn D, Shamardina O, Papadia S, Gomez K, BioResource N, Van Geet C, Koulman A, Ouwehand WH, Ghevaert C, Frontini M, Turro E, Freson K. Sphingolipid dysregulation due to lack of functional KDSR impairs proplatelet formation causing thrombocytopenia. Haematologica 2018; 104:1036-1045. [PMID: 30467204 PMCID: PMC6518879 DOI: 10.3324/haematol.2018.204784] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/19/2018] [Indexed: 12/02/2022] Open
Abstract
Sphingolipids are fundamental to membrane trafficking, apoptosis, and cell differentiation and proliferation. KDSR or 3-keto-dihydrosphingosine reductase is an essential enzyme for de novo sphingolipid synthesis, and pathogenic mutations in KDSR result in the severe skin disorder erythrokeratodermia variabilis et progressiva-4. Four of the eight reported cases also had thrombocytopenia but the underlying mechanism has remained unexplored. Here we expand upon the phenotypic spectrum of KDSR deficiency with studies in two siblings with novel compound heterozygous variants associated with thrombocytopenia, anemia, and minimal skin involvement. We report a novel phenotype of progressive juvenile myelofibrosis in the propositus, with spontaneous recovery of anemia and thrombocytopenia in the first decade of life. Examination of bone marrow biopsies showed megakaryocyte hyperproliferation and dysplasia. Megakaryocytes obtained by culture of CD34+ stem cells confirmed hyperproliferation and showed reduced proplatelet formation. The effect of KDSR insufficiency on the sphingolipid profile was unknown, and was explored in vivo and in vitro by a broad metabolomics screen that indicated activation of an in vivo compensatory pathway that leads to normalization of downstream metabolites such as ceramide. Differentiation of propositus-derived induced pluripotent stem cells to megakaryocytes followed by expression of functional KDSR showed correction of the aberrant cellular and biochemical phenotypes, corroborating the critical role of KDSR in proplatelet formation. Finally, Kdsr depletion in zebrafish recapitulated the thrombocytopenia and showed biochemical changes similar to those observed in the affected siblings. These studies support an important role for sphingolipids as regulators of cytoskeletal organization during megakaryopoiesis and proplatelet formation.
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Affiliation(s)
- Tadbir K Bariana
- Department of Haematology, University College London, UK.,The Katharine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, UK.,Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
| | - Veerle Labarque
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
| | - Jessica Heremans
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
| | - Chantal Thys
- NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
| | - Mara De Reys
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
| | - Daniel Greene
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
| | - Benjamin Jenkins
- NIHR Biomedical Research Centre Core Metabolomics and Lipidomics Laboratory, University of Cambridge, Cambridge Biomedical Campus, UK
| | - Luigi Grassi
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
| | - Denis Seyres
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
| | - Frances Burden
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK
| | - Deborah Whitehorn
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK
| | - Olga Shamardina
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK
| | - Sofia Papadia
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK
| | - Keith Gomez
- Department of Haematology, University College London, UK.,The Katharine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
| | - Nihr BioResource
- NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
| | - Chris Van Geet
- NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
| | - Albert Koulman
- NIHR Biomedical Research Centre Core Metabolomics and Lipidomics Laboratory, University of Cambridge, Cambridge Biomedical Campus, UK
| | - Willem H Ouwehand
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,British Heart Foundation Centre of Excellence, Division of Cardiovascular Medicine, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Cedric Ghevaert
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,British Heart Foundation Centre of Excellence, Division of Cardiovascular Medicine, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
| | - Mattia Frontini
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,British Heart Foundation Centre of Excellence, Division of Cardiovascular Medicine, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
| | - Ernest Turro
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK.,NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK.,NHS Blood and Transplant, Cambridge Biomedical Campus, UK.,Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
| | - Kathleen Freson
- NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK .,Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
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12
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Harrison PJ, Dunn T, Campopiano DJ. Sphingolipid biosynthesis in man and microbes. Nat Prod Rep 2018; 35:921-954. [PMID: 29863195 PMCID: PMC6148460 DOI: 10.1039/c8np00019k] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Indexed: 12/20/2022]
Abstract
A new review covering up to 2018 Sphingolipids are essential molecules that, despite their long history, are still stimulating interest today. The reasons for this are that, as well as playing structural roles within cell membranes, they have also been shown to perform a myriad of cell signalling functions vital to the correct function of eukaryotic and prokaryotic organisms. Indeed, sphingolipid disregulation that alters the tightly-controlled balance of these key lipids has been closely linked to a number of diseases such as diabetes, asthma and various neuropathologies. Sphingolipid biogenesis, metabolism and regulation is mediated by a large number of enzymes, proteins and second messengers. There appears to be a core pathway common to all sphingolipid-producing organisms but recent studies have begun to dissect out important, species-specific differences. Many of these have only recently been discovered and in most cases the molecular and biochemical details are only beginning to emerge. Where there is a direct link from classic biochemistry to clinical symptoms, a number a drug companies have undertaken a medicinal chemistry campaign to try to deliver a therapeutic intervention to alleviate a number of diseases. Where appropriate, we highlight targets where natural products have been exploited as useful tools. Taking all these aspects into account this review covers the structural, mechanistic and regulatory features of sphingolipid biosynthetic and metabolic enzymes.
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Affiliation(s)
- Peter J. Harrison
- School of Chemistry
, University of Edinburgh
,
David Brewster Road
, Edinburgh
, EH9 3FJ
, UK
.
| | - Teresa M. Dunn
- Department of Biochemistry and Molecular Biology
, Uniformed Services University
,
Bethesda
, Maryland
20814
, USA
| | - Dominic J. Campopiano
- School of Chemistry
, University of Edinburgh
,
David Brewster Road
, Edinburgh
, EH9 3FJ
, UK
.
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13
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Sands SA, LeVine SM. Substrate reduction therapy for Krabbe's disease. J Neurosci Res 2017; 94:1261-72. [PMID: 27638608 DOI: 10.1002/jnr.23791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/19/2016] [Accepted: 05/18/2016] [Indexed: 01/30/2023]
Abstract
Krabbe's disease (KD) is a lysosomal storage disorder in which galactosylceramide, a major glycosphingolipid of myelin, and psychosine (galactose-sphingosine) cannot be adequately metabolized because of a deficiency in galactosylceramidase. Substrate reduction therapy (SRT) has been tested in preclinical studies. The premise of SRT is to reduce the synthesis of substrates that are not adequately digested so that the substrate burden is lowered, resulting in less accumulation of unmetabolized material. SRT is used for Gaucher's disease, in which inhibitors of the terminal biosynthetic step are used. Unfortunately, an inhibitor for the final step of galactosylceramide biosynthesis, i.e., UDP glycosyltransferase 8 (a.k.a. UDP-galactose ceramide galactosyltransferase), has not been found. Approaches that inhibit an earlier biosynthetic step or that lessen the substrate burden by other means, such as genetic manipulations, have been tested in the twitcher mouse model of KD. Either as a stand-alone therapy or in combination with other approaches, SRT slowed the disease course, indicating that this approach has potential therapeutic value. For instance, in individuals with adult-onset disease, SRT theoretically could lessen the production of substrates so that residual enzymatic activity could adequately manage the lower substrate burden. In more severe forms of disease, SRT theoretically could be part of a combination therapy. However, SRT has the potential to impair normal function by reducing the synthesis of galactosylceramide to levels that impede myelin function, or SRT could have other deleterious effects. Thus, multiple issues need to be resolved before this approach is ready for testing in humans. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Scott A Sands
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Steven M LeVine
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas.
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14
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Boyden LM, Vincent NG, Zhou J, Hu R, Craiglow BG, Bayliss SJ, Rosman IS, Lucky AW, Diaz LA, Goldsmith LA, Paller AS, Lifton RP, Baserga SJ, Choate KA. Mutations in KDSR Cause Recessive Progressive Symmetric Erythrokeratoderma. Am J Hum Genet 2017; 100:978-984. [PMID: 28575652 DOI: 10.1016/j.ajhg.2017.05.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/08/2017] [Indexed: 11/18/2022] Open
Abstract
The discovery of new genetic determinants of inherited skin disorders has been instrumental to the understanding of epidermal function, differentiation, and renewal. Here, we show that mutations in KDSR (3-ketodihydrosphingosine reductase), encoding an enzyme in the ceramide synthesis pathway, lead to a previously undescribed recessive Mendelian disorder in the progressive symmetric erythrokeratoderma spectrum. This disorder is characterized by severe lesions of thick scaly skin on the face and genitals and thickened, red, and scaly skin on the hands and feet. Although exome sequencing revealed several of the KDSR mutations, we employed genome sequencing to discover a pathogenic 346 kb inversion in multiple probands, and cDNA sequencing and a splicing assay established that two mutations, including a recurrent silent third base change, cause exon skipping. Immunohistochemistry and yeast complementation studies demonstrated that the mutations cause defects in KDSR function. Systemic isotretinoin therapy has achieved nearly complete resolution in the two probands in whom it has been applied, consistent with the effects of retinoic acid on alternative pathways for ceramide generation.
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Affiliation(s)
- Lynn M Boyden
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Nicholas G Vincent
- Department of Microbiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jing Zhou
- Department of Dermatology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ronghua Hu
- Department of Dermatology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Brittany G Craiglow
- Department of Dermatology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Susan J Bayliss
- Division of Dermatology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Ilana S Rosman
- Division of Dermatology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Anne W Lucky
- Dermatologists of Southwest Ohio, Cincinnatti, OH 45247, USA
| | - Luis A Diaz
- Department of Dermatology, University of North Carolina School of Medicine, Chapel Hill, NC 27516, USA
| | - Lowell A Goldsmith
- Department of Dermatology, University of North Carolina School of Medicine, Chapel Hill, NC 27516, USA
| | - Amy S Paller
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Susan J Baserga
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Keith A Choate
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Dermatology, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA.
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15
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Corey BW, Thompson MG, Hittle LE, Jacobs AC, Asafo-Adjei EA, Huggins WM, Melander RJ, Melander C, Ernst RK, Zurawski DV. 1,2,4-Triazolidine-3-thiones Have Specific Activity against Acinetobacter baumannii among Common Nosocomial Pathogens. ACS Infect Dis 2017; 3:62-71. [PMID: 27764938 DOI: 10.1021/acsinfecdis.6b00133] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acinetobacter baumannii are Gram-negative bacilli that pose a constant threat to susceptible patients because of increased resistance to multiple antibiotics and persistence in the hospital environment. After genome analysis, we discovered that A. baumannii harbors genes that share homology to an enzymatic pathway that elongates long-chain fatty acids (LCFA) in fungi. Previously, 1,2,4-triazolidine-3-thiones (T-3-Ts) were shown to inhibit hyphae production in fungi, and this same LCFA elongation pathway was implicated as the possible target. Therefore, we investigated if T-3-Ts also have activity against multidrug-resistant A. baumannii. Surprisingly, all of the clinical isolates of A. baumannii that were tested have susceptibility to ECC145 and ECC188 with MIC90 values of 8.0 μg/mL. In contrast, reference strains and clinical isolates of other common nosocomial bacteria that lack the LCFA pathway also lacked susceptibility. Time-kill experiments revealed that both ECC145 and ECC188 have a bacteriostatic effect against A. baumannii. Mass spectrometry analysis suggested that exposure to T-3-Ts resulted in less LCFA production. Supplementation of media with either 0.02% w/v oleic or linoleic acid abrogated the bacteriostatic effect of the compounds, which again implicated LCFA elongation as the target. Our results suggest these molecules could be a promising start to further exploit what appears to be an important aspect of A. baumannii membrane function and integrity.
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Affiliation(s)
- Brendan W. Corey
- Wound Infections Department, Bacterial
Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - Mitchell G. Thompson
- Wound Infections Department, Bacterial
Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - Lauren E. Hittle
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
| | - Anna C. Jacobs
- Wound Infections Department, Bacterial
Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - Edward A. Asafo-Adjei
- Department of Veterinary Medicine, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - William M. Huggins
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8024, United States
| | - Roberta J. Melander
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8024, United States
| | - Christian Melander
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8024, United States
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
| | - Daniel V. Zurawski
- Wound Infections Department, Bacterial
Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
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16
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Abstract
Sphingolipids, a once overlooked class of lipids in plants, are now recognized as abundant and essential components of plasma membrane and other endomembranes of plant cells. In addition to providing structural integrity to plant membranes, sphingolipids contribute to Golgi trafficking and protein organizational domains in the plasma membrane. Sphingolipid metabolites have also been linked to the regulation of cellular processes, including programmed cell death. Advances in mass spectrometry-based sphingolipid profiling and analyses of Arabidopsis mutants have enabled fundamental discoveries in sphingolipid structural diversity, metabolism, and function that are reviewed here. These discoveries are laying the groundwork for the tailoring of sphingolipid biosynthesis and catabolism for improved tolerance of plants to biotic and abiotic stresses.
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Affiliation(s)
- Kyle D Luttgeharm
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, E318 Beadle Center, 1901 Vine Street, Lincoln, NE, 68588, USA
| | - Athen N Kimberlin
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, E318 Beadle Center, 1901 Vine Street, Lincoln, NE, 68588, USA
| | - Edgar B Cahoon
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, E318 Beadle Center, 1901 Vine Street, Lincoln, NE, 68588, USA.
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17
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Siow D, Sunkara M, Morris A, Wattenberg B. Regulation of de novo sphingolipid biosynthesis by the ORMDL proteins and sphingosine kinase-1. Adv Biol Regul 2014; 57:42-54. [PMID: 25319495 DOI: 10.1016/j.jbior.2014.09.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 09/03/2014] [Accepted: 09/04/2014] [Indexed: 12/11/2022]
Abstract
Sphingolipids are a diverse set of structurally and metabolically related lipids that have numerous functions in cell structure and signaling. The regulation of these lipids is critical for normal cell function and disregulation has been implicated in pathophysiological conditions such as cancer and inflammation. Here we examine control of the initiating, and rate limiting, enzyme in sphingolipid biosynthesis, serine palmitoyltransferase (SPT). We find that de novo synthesis of sphingolipid is stimulated by a number of cancer chemotherapeutics, suggesting that this may be an important aspect of their cytotoxic effects. The three ORMDL proteins are membrane proteins of the endoplasmic reticulum related to the yeast Orm proteins, which have been shown to be homeostatic regulators of SPT. We find that the ORMDL proteins are also negative regulators of SPT that transmit cellular levels of sphingolipids to SPT. The three isoforms have redundant functions in this system. The sphingosine kinases (sphingosine kinase-1 and -2) phosphorylate both sphingosine, which is released from ceramide, but also dihydrosphingosine, which is in the de novo biosynthetic pathway. We therefore examined the role of the sphingosine kinases in controlling de novo ceramide biosynthesis and find that sphingosine kinase-1 does indeed act as a negative regulator of this pathway. This establishes that sphingosine kinase, in addition to producing sphingosine-1-phosphate as a signaling molecule, also consumes dihydrosphingosine to regulate ceramide synthesis. Our studies demonstrate that there are multiple mechanisms of regulation of SPT and suggest that these regulators are important mediators of cell stress responses.
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Affiliation(s)
- Deanna Siow
- James Graham Brown Cancer Center, University of Louisville School of Medicine, 505 South Hancock St., Louisville, KY 40202, USA
| | - Manjula Sunkara
- Division of Cardiovascular Medicine, Gill Heart Institute, University of Kentucky Lexington, Lexington, KY 40536, USA; Department of Veterans Affairs Medical Center, Lexington, KY, USA
| | - Andrew Morris
- Division of Cardiovascular Medicine, Gill Heart Institute, University of Kentucky Lexington, Lexington, KY 40536, USA; Department of Veterans Affairs Medical Center, Lexington, KY, USA
| | - Binks Wattenberg
- James Graham Brown Cancer Center, University of Louisville School of Medicine, 505 South Hancock St., Louisville, KY 40202, USA; Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, 505 South Hancock St., Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, 505 South Hancock St., Louisville, KY 40202, USA.
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18
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Loh KC, Baldwin D, Saba JD. Sphingolipid signaling and hematopoietic malignancies: to the rheostat and beyond. Anticancer Agents Med Chem 2012; 11:782-93. [PMID: 21707493 DOI: 10.2174/187152011797655159] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/06/2011] [Accepted: 05/09/2011] [Indexed: 12/20/2022]
Abstract
Sphingosine-1-phosphate (S1P) is a bioactive lipid with diverse functions including the promotion of cell survival, proliferation and migration, as well as the regulation of angiogenesis, inflammation, immunity, vascular permeability and nuclear mechanisms that control gene transcription. S1P is derived from metabolism of ceramide, which itself has diverse and generally growth-inhibitory effects through its impact on downstream targets involved in regulation of apoptosis, senescence and cell cycle progression. Regulation of ceramide, S1P and the biochemical steps that modulate the balance and interconversion of these two lipids are major determinants of cell fate, a concept referred to as the "sphingolipid rheostat." There is abundant evidence that the sphingolipid rheostat plays a role in the origination, progression and drug resistance patterns of hematopoietic malignancies. The pathway has also been exploited to circumvent the problem of chemotherapy resistance in leukemia and lymphoma. Given the broad effects of sphingolipids, targeting multiple steps in the metabolic pathway may provide possible therapeutic avenues. However, new observations have revealed that sphingolipid signaling effects are more complex than previously recognized, requiring a revision of the sphingolipid rheostat model. Here, we summarize recent insights regarding the sphingolipid metabolic pathway and its role in hematopoietic malignancies.
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Affiliation(s)
- Kenneth C Loh
- Children's Hospital Oakland Research Institute, Center for Cancer Research, CA 94609, USA
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19
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Chao DY, Gable K, Chen M, Baxter I, Dietrich CR, Cahoon EB, Guerinot ML, Lahner B, Lü S, Markham JE, Morrissey J, Han G, Gupta SD, Harmon JM, Jaworski JG, Dunn TM, Salt DE. Sphingolipids in the root play an important role in regulating the leaf ionome in Arabidopsis thaliana. THE PLANT CELL 2011; 23:1061-81. [PMID: 21421810 PMCID: PMC3082254 DOI: 10.1105/tpc.110.079095] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 01/19/2011] [Accepted: 02/14/2011] [Indexed: 05/18/2023]
Abstract
Sphingolipid synthesis is initiated by condensation of Ser with palmitoyl-CoA producing 3-ketodihydrosphinganine (3-KDS), which is reduced by a 3-KDS reductase to dihydrosphinganine. Ser palmitoyltransferase is essential for plant viability. Arabidopsis thaliana contains two genes (At3g06060/TSC10A and At5g19200/TSC10B) encoding proteins with significant similarity to the yeast 3-KDS reductase, Tsc10p. Heterologous expression in yeast of either Arabidopsis gene restored 3-KDS reductase activity to the yeast tsc10Δ mutant, confirming both as bona fide 3-KDS reductase genes. Consistent with sphingolipids having essential functions in plants, double mutant progeny lacking both genes were not recovered from crosses of single tsc10A and tsc10B mutants. Although the 3-KDS reductase genes are functionally redundant and ubiquitously expressed in Arabidopsis, 3-KDS reductase activity was reduced to 10% of wild-type levels in the loss-of-function tsc10a mutant, leading to an altered sphingolipid profile. This perturbation of sphingolipid biosynthesis in the Arabidopsis tsc10a mutant leads an altered leaf ionome, including increases in Na, K, and Rb and decreases in Mg, Ca, Fe, and Mo. Reciprocal grafting revealed that these changes in the leaf ionome are driven by the root and are associated with increases in root suberin and alterations in Fe homeostasis.
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Affiliation(s)
- Dai-Yin Chao
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906, USA
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20
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Gable K, Gupta SD, Han G, Niranjanakumari S, Harmon JM, Dunn TM. A disease-causing mutation in the active site of serine palmitoyltransferase causes catalytic promiscuity. J Biol Chem 2010; 285:22846-52. [PMID: 20504773 DOI: 10.1074/jbc.m110.122259] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The autosomal dominant peripheral sensory neuropathy HSAN1 results from mutations in the LCB1 subunit of serine palmitoyltransferase (SPT). Serum from patients and transgenic mice expressing a disease-causing mutation (C133W) contain elevated levels of 1-deoxysphinganine (1-deoxySa), which presumably arise from inappropriate condensation of alanine with palmitoyl-CoA. Mutant heterodimeric SPT is catalytically inactive. However, mutant heterotrimeric SPT has approximately 10-20% of wild-type activity and supports growth of yeast cells lacking endogenous SPT. In addition, long chain base profiling revealed the synthesis of significantly more 1-deoxySa in yeast and mammalian cells expressing the heterotrimeric mutant enzyme than in cells expressing wild-type enzyme. Wild-type and mutant enzymes had similar affinities for serine. Surprisingly, the enzymes also had similar affinities for alanine, indicating that the major affect of the C133W mutation is to enhance activation of alanine for condensation with the acyl-CoA substrate. In vivo synthesis of 1-deoxySa by the mutant enzyme was proportional to the ratio of alanine to serine in the growth media, suggesting that this ratio can be used to modulate the relative synthesis of sphinganine and 1-deoxySa. By expressing SPT as a single-chain fusion protein to ensure stoichiometric expression of all three subunits, we showed that GADD153, a marker for endoplasmic reticulum stress, was significantly elevated in cells expressing mutant heterotrimers. GADD153 was also elevated in cells treated with 1-deoxySa. Taken together, these data indicate that the HSAN1 mutations perturb the active site of SPT resulting in a gain of function that is responsible for the HSAN1 phenotype.
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Affiliation(s)
- Kenneth Gable
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20184-4799, USA
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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