1
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Iezhitsa I, Agarwal R, Agarwal P. Unveiling enigmatic essence of Sphingolipids: A promising avenue for glaucoma treatment. Vision Res 2024; 221:108434. [PMID: 38805893 DOI: 10.1016/j.visres.2024.108434] [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] [Received: 04/01/2024] [Revised: 05/05/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024]
Abstract
Treatment of glaucoma, the leading cause of irreversible blindness, remains challenging. The apoptotic loss of retinal ganglion cells (RGCs) in glaucoma is the pathological hallmark. Current treatments often remain suboptimal as they aim to halt RGC loss secondary to reduction of intraocular pressure. The pathophysiological targets for exploring direct neuroprotective approaches, therefore are highly relevant. Sphingolipids have emerged as significant target molecules as they are not only the structural components of various cell constituents, but they also serve as signaling molecules that regulate molecular pathways involved in cell survival and death. Investigations have shown that a critical balance among various sphingolipid species, particularly the ceramide and sphingosine-1-phosphate play a role in deciding the fate of the cell. In this review we briefly discuss the metabolic interconversion of sphingolipid species to get an insight into "sphingolipid rheostat", the dynamic balance among metabolites. Further we highlight the role of sphingolipids in the key pathophysiological mechanisms that lead to glaucomatous loss of RGCs. Lastly, we summarize the potential drug candidates that have been investigated for their neuroprotective effects in glaucoma via their effects on sphingolipid axis.
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2
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Brown RDR, Spiegel S. ORMDL in metabolic health and disease. Pharmacol Ther 2023; 245:108401. [PMID: 37003301 PMCID: PMC10148913 DOI: 10.1016/j.pharmthera.2023.108401] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Obesity is a key risk factor for the development of metabolic disease. Bioactive sphingolipid metabolites are among the lipids increased in obesity. Obesogenic saturated fatty acids are substrates for serine palmitoyltransferase (SPT) the rate-limiting step in de novo sphingolipid biosynthesis. The mammalian orosomucoid-like protein isoforms ORMDL1-3 negatively regulate SPT activity. Here we summarize evidence that dysregulation of sphingolipid metabolism and SPT activity correlates with pathogenesis of obesity. This review also discusses the current understanding of the function of SPT and ORMDL in obesity and metabolic disease. Gaps and limitations in current knowledge are highlighted together with the need to further understand how ORMDL3, which has been identified as an obesity-related gene, contributes to the pathogenesis of obesity and development of metabolic disease related to its physiological functions. Finally, we point out the needs to move this young field of research forward.
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Affiliation(s)
- Ryan D R Brown
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
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3
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Srivastava S, Shaked HM, Gable K, Gupta SD, Pan X, Somashekarappa N, Han G, Mohassel P, Gotkine M, Doney E, Goldenberg P, Tan QKG, Gong Y, Kleinstiver B, Wishart B, Cope H, Pires CB, Stutzman H, Spillmann RC, Sadjadi R, Elpeleg O, Lee CH, Bellen HJ, Edvardson S, Eichler F, Dunn TM, Dai H, Dhar SU, Emrick LT, Goldman AM, Hanchard NA, Jamal F, Karaviti L, Lalani SR, Lee BH, Lewis RA, Marom R, Moretti PM, Murdock DR, Nicholas SK, Orengo JP, Posey JE, Potocki L, Rosenfeld JA, Samson SL, Scott DA, Tran AA, Vogel TP, Wangler MF, Yamamoto S, Eng CM, Liu P, Ward PA, Behrens E, Deardorff M, Falk M, Hassey K, Sullivan K, Vanderver A, Goldstein DB, Cope H, McConkie-Rosell A, Schoch K, Shashi V, Smith EC, Spillmann RC, Sullivan JA, Tan QKG, Walley NM, Agrawal PB, Beggs AH, Berry GT, Briere LC, Cobban LA, Coggins M, Cooper CM, Fieg EL, High F, Holm IA, Korrick S, Krier JB, Lincoln SA, Loscalzo J, Maas RL, MacRae CA, Pallais JC, Rao DA, Rodan LH, Silverman EK, Stoler JM, Sweetser DA, Walker M, Walsh CA, Esteves C, Kelley EG, Kohane IS, LeBlanc K, McCray AT, Nagy A, Dasari S, Lanpher BC, Lanza IR, Morava E, Oglesbee D, Bademci G, Barbouth D, Bivona S, Carrasquillo O, Chang TCP, Forghani I, Grajewski A, Isasi R, Lam B, Levitt R, Liu XZ, McCauley J, Sacco R, Saporta M, Schaechter J, Tekin M, Telischi F, Thorson W, Zuchner S, Colley HA, Dayal JG, Eckstein DJ, Findley LC, Krasnewich DM, Mamounas LA, Manolio TA, Mulvihill JJ, LaMoure GL, Goldrich MP, Urv TK, Doss AL, Acosta MT, Bonnenmann C, D’Souza P, Draper DD, Ferreira C, Godfrey RA, Groden CA, Macnamara EF, Maduro VV, Markello TC, Nath A, Novacic D, Pusey BN, Toro C, Wahl CE, Baker E, Burke EA, Adams DR, Gahl WA, Malicdan MCV, Tifft CJ, Wolfe LA, Yang J, Power B, Gochuico B, Huryn L, Latham L, Davis J, Mosbrook-Davis D, Rossignol F, Solomon B, MacDowall J, Thurm A, Zein W, Yousef M, Adam M, Amendola L, Bamshad M, Beck A, Bennett J, Berg-Rood B, Blue E, Boyd B, Byers P, Chanprasert S, Cunningham M, Dipple K, Doherty D, Earl D, Glass I, Golden-Grant K, Hahn S, Hing A, Hisama FM, Horike-Pyne M, Jarvik GP, Jarvik J, Jayadev S, Lam C, Maravilla K, Mefford H, Merritt JL, Mirzaa G, Nickerson D, Raskind W, Rosenwasser N, Scott CR, Sun A, Sybert V, Wallace S, Wener M, Wenger T, Ashley EA, Bejerano G, Bernstein JA, Bonner D, Coakley TR, Fernandez L, Fisher PG, Fresard L, Hom J, Huang Y, Kohler JN, Kravets E, Majcherska MM, Martin BA, Marwaha S, McCormack CE, Raja AN, Reuter CM, Ruzhnikov M, Sampson JB, Smith KS, Sutton S, Tabor HK, Tucker BM, Wheeler MT, Zastrow DB, Zhao C, Byrd WE, Crouse AB, Might M, Nakano-Okuno M, Whitlock J, Brown G, Butte MJ, Dell’Angelica EC, Dorrani N, Douine ED, Fogel BL, Gutierrez I, Huang A, Krakow D, Lee H, Loo SK, Mak BC, Martin MG, Martínez-Agosto JA, McGee E, Nelson SF, Nieves-Rodriguez S, Palmer CGS, Papp JC, Parker NH, Renteria G, Signer RH, Sinsheimer JS, Wan J, Wang LK, Perry KW, Woods JD, Alvey J, Andrews A, Bale J, Bohnsack J, Botto L, Carey J, Pace L, Longo N, Marth G, Moretti P, Quinlan A, Velinder M, Viskochi D, Bayrak-Toydemir P, Mao R, Westerfield M, Bican A, Brokamp E, Duncan L, Hamid R, Kennedy J, Kozuira M, Newman JH, PhillipsIII JA, Rives L, Robertson AK, Solem E, Cogan JD, Cole FS, Hayes N, Kiley D, Sisco K, Wambach J, Wegner D, Baldridge D, Pak S, Schedl T, Shin J, Solnica-Krezel L, Sadjadi R, Elpeleg O, Lee CH, Bellen HJ, Edvardson S, Eichler F, Dunn TM. SPTSSA variants alter sphingolipid synthesis and cause a complex hereditary spastic paraplegia. Brain 2023; 146:1420-1435. [PMID: 36718090 PMCID: PMC10319774 DOI: 10.1093/brain/awac460] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 11/03/2022] [Accepted: 11/19/2022] [Indexed: 02/01/2023] Open
Abstract
Sphingolipids are a diverse family of lipids with critical structural and signalling functions in the mammalian nervous system, where they are abundant in myelin membranes. Serine palmitoyltransferase, the enzyme that catalyses the rate-limiting reaction of sphingolipid synthesis, is composed of multiple subunits including an activating subunit, SPTSSA. Sphingolipids are both essential and cytotoxic and their synthesis must therefore be tightly regulated. Key to the homeostatic regulation are the ORMDL proteins that are bound to serine palmitoyltransferase and mediate feedback inhibition of enzymatic activity when sphingolipid levels become excessive. Exome sequencing identified potential disease-causing variants in SPTSSA in three children presenting with a complex form of hereditary spastic paraplegia. The effect of these variants on the catalytic activity and homeostatic regulation of serine palmitoyltransferase was investigated in human embryonic kidney cells, patient fibroblasts and Drosophila. Our results showed that two different pathogenic variants in SPTSSA caused a hereditary spastic paraplegia resulting in progressive motor disturbance with variable sensorineural hearing loss and language/cognitive dysfunction in three individuals. The variants in SPTSSA impaired the negative regulation of serine palmitoyltransferase by ORMDLs leading to excessive sphingolipid synthesis based on biochemical studies and in vivo studies in Drosophila. These findings support the pathogenicity of the SPTSSA variants and point to excessive sphingolipid synthesis due to impaired homeostatic regulation of serine palmitoyltransferase as responsible for defects in early brain development and function.
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Affiliation(s)
- Siddharth Srivastava
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, BostonChildren's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hagar Mor Shaked
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Kenneth Gable
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Sita D Gupta
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Niranjanakumari Somashekarappa
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Gongshe Han
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20814, USA
| | - Marc Gotkine
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | | | - Paula Goldenberg
- Department of Pediatrics, Section on Medical Genetics, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Queenie K G Tan
- Department of Pediatrics, Division of Medical Genetics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yi Gong
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Benjamin Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Brian Wishart
- Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Heidi Cope
- Department of Pediatrics, Division of Medical Genetics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Claudia Brito Pires
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Hannah Stutzman
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Rebecca C Spillmann
- Department of Pediatrics, Division of Medical Genetics, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Reza Sadjadi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Chia-Hsueh Lee
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Simon Edvardson
- Pediatric Neurology Unit, Hadassah University Hospital, Mount Scopus, Jerusalem 91240, Israel
| | - Florian Eichler
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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- Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, MA 02114 , USA
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem , Jerusalem 91120 , Israel
| | - Chia-Hsueh Lee
- Department of Structural Biology, St. Jude Children’s Research Hospital , Memphis, TN 38105 , USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine , Houston, TX 77030 , USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital , Houston, TX 77030 , USA
| | - Simon Edvardson
- Pediatric Neurology Unit, Hadassah University Hospital, Mount Scopus , Jerusalem 91240 , Israel
| | - Florian Eichler
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, MA 02114 , USA
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School , Boston, MA 02114 , USA
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences , Bethesda, MD 20814 , USA
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4
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Sasset L, Chowdhury KH, Manzo OL, Rubinelli L, Konrad C, Maschek JA, Manfredi G, Holland WL, Di Lorenzo A. Sphingosine-1-phosphate controls endothelial sphingolipid homeostasis via ORMDL. EMBO Rep 2023; 24:e54689. [PMID: 36408842 PMCID: PMC9827560 DOI: 10.15252/embr.202254689] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 10/04/2022] [Accepted: 10/28/2022] [Indexed: 11/22/2022] Open
Abstract
Disruption of sphingolipid homeostasis and signaling has been implicated in diabetes, cancer, cardiometabolic, and neurodegenerative disorders. Yet, mechanisms governing cellular sensing and regulation of sphingolipid homeostasis remain largely unknown. In yeast, serine palmitoyltransferase, catalyzing the first and rate-limiting step of sphingolipid de novo biosynthesis, is negatively regulated by Orm1 and 2. Lowering sphingolipids triggers Orms phosphorylation, upregulation of serine palmitoyltransferase activity and sphingolipid de novo biosynthesis. However, mammalian orthologs ORMDLs lack the N-terminus hosting the phosphosites. Thus, which sphingolipid(s) are sensed by the cells, and mechanisms of homeostasis remain largely unknown. Here, we identify sphingosine-1-phosphate (S1P) as key sphingolipid sensed by cells via S1PRs to maintain homeostasis. The increase in S1P-S1PR signaling stabilizes ORMDLs, restraining SPT activity. Mechanistically, the hydroxylation of ORMDLs at Pro137 allows a constitutive degradation of ORMDLs via ubiquitin-proteasome pathway, preserving SPT activity. Disrupting S1PR/ORMDL axis results in ceramide accrual, mitochondrial dysfunction, impaired signal transduction, all underlying endothelial dysfunction, early event in the onset of cardio- and cerebrovascular diseases. Our discovery may provide the molecular basis for therapeutic intervention restoring sphingolipid homeostasis.
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Affiliation(s)
- Linda Sasset
- Department of Pathology and Laboratory MedicineCardiovascular Research Institute, Weill Cornell MedicineNew YorkNYUSA
- Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNYUSA
| | - Kamrul H Chowdhury
- Department of Nutrition and Integrative PhysiologyUniversity of Utah College of HealthSalt Lake CityUTUSA
| | - Onorina L Manzo
- Department of Pathology and Laboratory MedicineCardiovascular Research Institute, Weill Cornell MedicineNew YorkNYUSA
- Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNYUSA
- Department of PharmacyUniversity of Naples “Federico II”NaplesItaly
| | - Luisa Rubinelli
- Department of Pathology and Laboratory MedicineCardiovascular Research Institute, Weill Cornell MedicineNew YorkNYUSA
- Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNYUSA
| | - Csaba Konrad
- Department of Nutrition and Integrative PhysiologyUniversity of Utah College of HealthSalt Lake CityUTUSA
| | - J Alan Maschek
- Department of Nutrition and Integrative PhysiologyUniversity of Utah College of HealthSalt Lake CityUTUSA
| | - Giovanni Manfredi
- Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNYUSA
| | - William L Holland
- Department of Nutrition and Integrative PhysiologyUniversity of Utah College of HealthSalt Lake CityUTUSA
| | - Annarita Di Lorenzo
- Department of Pathology and Laboratory MedicineCardiovascular Research Institute, Weill Cornell MedicineNew YorkNYUSA
- Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNYUSA
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5
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Pan X, Dutta D, Lu S, Bellen HJ. Sphingolipids in neurodegenerative diseases. Front Neurosci 2023; 17:1137893. [PMID: 36875645 PMCID: PMC9978793 DOI: 10.3389/fnins.2023.1137893] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 01/27/2023] [Indexed: 02/18/2023] Open
Abstract
Neurodegenerative Diseases (NDDs) are a group of disorders that cause progressive deficits of neuronal function. Recent evidence argues that sphingolipid metabolism is affected in a surprisingly broad set of NDDs. These include some lysosomal storage diseases (LSDs), hereditary sensory and autonomous neuropathy (HSAN), hereditary spastic paraplegia (HSP), infantile neuroaxonal dystrophy (INAD), Friedreich's ataxia (FRDA), as well as some forms of amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Many of these diseases have been modeled in Drosophila melanogaster and are associated with elevated levels of ceramides. Similar changes have also been reported in vertebrate cells and mouse models. Here, we summarize studies using fly models and/or patient samples which demonstrate the nature of the defects in sphingolipid metabolism, the organelles that are implicated, the cell types that are initially affected, and potential therapeutics for these diseases.
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Affiliation(s)
- Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
| | - Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
| | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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6
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Sandhoff R, Sandhoff K. Neuronal Ganglioside and Glycosphingolipid (GSL) Metabolism and Disease : Cascades of Secondary Metabolic Errors Can Generate Complex Pathologies (in LSDs). ADVANCES IN NEUROBIOLOGY 2023; 29:333-390. [PMID: 36255681 DOI: 10.1007/978-3-031-12390-0_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Glycosphingolipids (GSLs) are a diverse group of membrane components occurring mainly on the surfaces of mammalian cells. They and their metabolites have a role in intercellular communication, serving as versatile biochemical signals (Kaltner et al, Biochem J 476(18):2623-2655, 2019) and in many cellular pathways. Anionic GSLs, the sialic acid containing gangliosides (GGs), are essential constituents of neuronal cell surfaces, whereas anionic sulfatides are key components of myelin and myelin forming oligodendrocytes. The stepwise biosynthetic pathways of GSLs occur at and lead along the membranes of organellar surfaces of the secretory pathway. After formation of the hydrophobic ceramide membrane anchor of GSLs at the ER, membrane-spanning glycosyltransferases (GTs) of the Golgi and Trans-Golgi network generate cell type-specific GSL patterns for cellular surfaces. GSLs of the cellular plasma membrane can reach intra-lysosomal, i.e. luminal, vesicles (ILVs) by endocytic pathways for degradation. Soluble glycoproteins, the glycosidases, lipid binding and transfer proteins and acid ceramidase are needed for the lysosomal catabolism of GSLs at ILV-membrane surfaces. Inherited mutations triggering a functional loss of glycosylated lysosomal hydrolases and lipid binding proteins involved in GSL degradation cause a primary lysosomal accumulation of their non-degradable GSL substrates in lysosomal storage diseases (LSDs). Lipid binding proteins, the SAPs, and the various lipids of the ILV-membranes regulate GSL catabolism, but also primary storage compounds such as sphingomyelin (SM), cholesterol (Chol.), or chondroitin sulfate can effectively inhibit catabolic lysosomal pathways of GSLs. This causes cascades of metabolic errors, accumulating secondary lysosomal GSL- and GG- storage that can trigger a complex pathology (Breiden and Sandhoff, Int J Mol Sci 21(7):2566, 2020).
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Affiliation(s)
- Roger Sandhoff
- Lipid Pathobiochemistry Group, German Cancer Research Center, Heidelberg, Germany
| | - Konrad Sandhoff
- LIMES, c/o Kekule-Institute for Organic Chemistry and Biochemistry, University of Bonn, Bonn, Germany.
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7
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Targeting the Sphingolipid Rheostat in Gliomas. Int J Mol Sci 2022; 23:ijms23169255. [PMID: 36012521 PMCID: PMC9408832 DOI: 10.3390/ijms23169255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/12/2022] [Accepted: 08/14/2022] [Indexed: 11/26/2022] Open
Abstract
Gliomas are highly aggressive cancer types that are in urgent need of novel drugs and targeted therapies. Treatment protocols have not improved in over a decade, and glioma patient survival remains among the worst of all cancer types. As a result, cancer metabolism research has served as an innovative approach to identifying novel glioma targets and improving our understanding of brain tumors. Recent research has uncovered a unique metabolic vulnerability in the sphingolipid pathways of gliomas that possess the IDH1 mutation. Sphingolipids are a family of lipid signaling molecules that play a variety of second messenger functions in cellular regulation. The two primary metabolites, sphingosine-1-phosphate (S1P) and ceramide, maintain a rheostat balance and play opposing roles in cell survival and proliferation. Altering the rheostat such that the pro-apoptotic signaling of the ceramides outweighs the pro-survival S1P signaling in glioma cells diminishes the hallmarks of cancer and enhances tumor cell death. Throughout this review, we discuss the sphingolipid pathway and identify the enzymes that can be most effectively targeted to alter the sphingolipid rheostat and enhance apoptosis in gliomas. We discuss each pathway’s steps based on their site of occurrence in the organelles and postulate novel targets that can effectively exploit this vulnerability.
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8
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Worgall TS. Sphingolipids and Asthma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1372:145-155. [DOI: 10.1007/978-981-19-0394-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Sasset L, Di Lorenzo A. Sphingolipid Metabolism and Signaling in Endothelial Cell Functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1372:87-117. [PMID: 35503177 DOI: 10.1007/978-981-19-0394-6_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The endothelium, inner layer of blood vessels, constitutes a metabolically active paracrine, endocrine, and autocrine organ, able to sense the neighboring environment and exert a variety of biological functions important to preserve the health of vasculature, tissues, and organs. Sphingolipids are both fundamental structural components of the eukaryotic membranes and signaling molecules regulating a variety of biological functions. Ceramide and sphingosine-1-phosphate (S1P), bioactive sphingolipids, have emerged as important regulators of cardiovascular functions in health and disease. In this review we discuss recent insights into the role of ceramide and S1P biosynthesis and signaling in regulating endothelial cell functions, in health and diseases. We also highlight advances into the mechanisms regulating serine palmitoyltransferase, the first and rate-limiting enzyme of de novo sphingolipid biosynthesis, with an emphasis on its inhibitors, ORMDL and NOGO-B. Understanding the molecular mechanisms regulating the sphingolipid de novo biosynthesis may provide the foundation for therapeutic modulation of this pathway in a variety of conditions, including cardiovascular diseases, associated with derangement of this pathway.
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Affiliation(s)
- Linda Sasset
- Department of Pathology and Laboratory Medicine, Cardiovascular Research Institute, Feil Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Annarita Di Lorenzo
- Department of Pathology and Laboratory Medicine, Cardiovascular Research Institute, Feil Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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10
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Crosstalk between ORMDL3, serine palmitoyltransferase, and 5-lipoxygenase in the sphingolipid and eicosanoid metabolic pathways. J Lipid Res 2021; 62:100121. [PMID: 34560079 PMCID: PMC8527048 DOI: 10.1016/j.jlr.2021.100121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/23/2021] [Accepted: 09/08/2021] [Indexed: 11/21/2022] Open
Abstract
Leukotrienes (LTs) and sphingolipids are critical lipid mediators participating in numerous cellular signal transduction events and developing various disorders, such as bronchial hyperactivity leading to asthma. Enzymatic reactions initiating production of these lipid mediators involve 5-lipoxygenase (5-LO)-mediated conversion of arachidonic acid to LTs and serine palmitoyltransferase (SPT)-mediated de novo synthesis of sphingolipids. Previous studies have shown that endoplasmic reticulum membrane protein ORM1-like protein 3 (ORMDL3) inhibits the activity of SPT and subsequent sphingolipid synthesis. However, the role of ORMDL3 in the synthesis of LTs is not known. In this study, we used peritoneal-derived mast cells isolated from ORMDL3 KO or control mice and examined their calcium mobilization, degranulation, NF-κB inhibitor-α phosphorylation, and TNF-α production. We found that peritoneal-derived mast cells with ORMDL3 KO exhibited increased responsiveness to antigen. Detailed lipid analysis showed that compared with WT cells, ORMDL3-deficient cells exhibited not only enhanced production of sphingolipids but also of LT signaling mediators LTB4, 6t-LTB4, LTC4, LTB5, and 6t-LTB5. The crosstalk between ORMDL3 and 5-LO metabolic pathways was supported by the finding that endogenous ORMDL3 and 5-LO are localized in similar endoplasmic reticulum domains in human mast cells and that ORMDL3 physically interacts with 5-LO. Further experiments showed that 5-LO also interacts with the long-chain 1 and long-chain 2 subunits of SPT. In agreement with these findings, 5-LO knockdown increased ceramide levels, and silencing of SPTLC1 decreased arachidonic acid metabolism to LTs to levels observed upon 5-LO knockdown. These results demonstrate functional crosstalk between the LT and sphingolipid metabolic pathways, leading to the production of lipid signaling mediators.
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11
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Mohassel P, Donkervoort S, Lone MA, Nalls M, Gable K, Gupta SD, Foley AR, Hu Y, Saute JAM, Moreira AL, Kok F, Introna A, Logroscino G, Grunseich C, Nickolls AR, Pourshafie N, Neuhaus SB, Saade D, Gangfuß A, Kölbel H, Piccus Z, Le Pichon CE, Fiorillo C, Ly CV, Töpf A, Brady L, Specht S, Zidell A, Pedro H, Mittelmann E, Thomas FP, Chao KR, Konersman CG, Cho MT, Brandt T, Straub V, Connolly AM, Schara U, Roos A, Tarnopolsky M, Höke A, Brown RH, Lee CH, Hornemann T, Dunn TM, Bönnemann CG. Childhood amyotrophic lateral sclerosis caused by excess sphingolipid synthesis. Nat Med 2021; 27:1197-1204. [PMID: 34059824 PMCID: PMC9309980 DOI: 10.1038/s41591-021-01346-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive, neurodegenerative disease of the lower and upper motor neurons with sporadic or hereditary occurrence. Age of onset, pattern of motor neuron degeneration and disease progression vary widely among individuals with ALS. Various cellular processes may drive ALS pathomechanisms, but a monogenic direct metabolic disturbance has not been causally linked to ALS. Here we show SPTLC1 variants that result in unrestrained sphingoid base synthesis cause a monogenic form of ALS. We identified four specific, dominantly acting SPTLC1 variants in seven families manifesting as childhood-onset ALS. These variants disrupt the normal homeostatic regulation of serine palmitoyltransferase (SPT) by ORMDL proteins, resulting in unregulated SPT activity and elevated levels of canonical SPT products. Notably, this is in contrast with SPTLC1 variants that shift SPT amino acid usage from serine to alanine, result in elevated levels of deoxysphingolipids and manifest with the alternate phenotype of hereditary sensory and autonomic neuropathy. We custom designed small interfering RNAs that selectively target the SPTLC1 ALS allele for degradation, leave the normal allele intact and normalize sphingolipid levels in vitro. The role of primary metabolic disturbances in ALS has been elusive; this study defines excess sphingolipid biosynthesis as a fundamental metabolic mechanism for motor neuron disease.
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Affiliation(s)
- Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Museer A Lone
- Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Matthew Nalls
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Kenneth Gable
- Department of Biochemistry and Molecular Biology, Uniformed Services University of Health Sciences, Bethesda, MD, USA
| | - Sita D Gupta
- Department of Biochemistry and Molecular Biology, Uniformed Services University of Health Sciences, Bethesda, MD, USA
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Ying Hu
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Jonas Alex Morales Saute
- Medical Genetics division and Neurology division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil; Graduate Program in Medicine: Medical Sciences, and Internal Medicine Department; Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Ana Lucila Moreira
- Neurology Department, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Fernando Kok
- Neurogenetics Outpatient Service, Neurology Department, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil and Mendelics, São Paulo, Brazil
| | - Alessandro Introna
- Neurology Unit, Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari 'Aldo Moro', Bari, Italy
| | - Giancarlo Logroscino
- Neurology Unit, Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari 'Aldo Moro', Bari, Italy
- Department of Clinical Research in Neurology, Center for Neurodegenerative Diseases and the Aging Brain, University of Bari at 'Pia Fondazione Card G. Panico' Hospital Tricase (Le), Bari, Italy
| | - Christopher Grunseich
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Alec R Nickolls
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Naemeh Pourshafie
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Sarah B Neuhaus
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Dimah Saade
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Andrea Gangfuß
- Department of Paediatric Neurology, Center for Neuromuscular Disorders in Children and Adolescents, University Clinic Essen, University of Duisburg-Essen, Duisburg-Essen, Germany
| | - Heike Kölbel
- Department of Paediatric Neurology, Center for Neuromuscular Disorders in Children and Adolescents, University Clinic Essen, University of Duisburg-Essen, Duisburg-Essen, Germany
| | - Zoe Piccus
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Claire E Le Pichon
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Chiara Fiorillo
- Paediatric Neurology and Muscular Diseases Unit, G. Gaslini Institute and Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health University of Genoa, Genoa, Italy
| | - Cindy V Ly
- Department of Neurology, Washington University in Saint Louis School of Medicine, Saint Louis, MO, USA
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Lauren Brady
- Division of Neuromuscular & Neurometabolic Disorders, Department of Paediatrics, McMaster University, Hamilton Health Sciences Centre, Hamilton, Ontario, Canada
| | - Sabine Specht
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Aliza Zidell
- Center for Genetic and Genomic Medicine, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Helio Pedro
- Center for Genetic and Genomic Medicine, Hackensack University Medical Center, Hackensack Meridian School of Medicine, Hackensack, NJ, USA
| | - Eric Mittelmann
- Department of Neurology, Hereditary Neuropathy Foundation Center of Excellence, Neuroscience Institute, Hackensack University Medical Center, Hackensack Meridian School of Medicine, Hackensack, NJ, USA
| | - Florian P Thomas
- Department of Neurology, Hereditary Neuropathy Foundation Center of Excellence, Neuroscience Institute, Hackensack University Medical Center, Hackensack Meridian School of Medicine, Hackensack, NJ, USA
| | - Katherine R Chao
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Chamindra G Konersman
- Department of Neurosciences, University of California, San Diego, San Diego, CA, USA
| | | | | | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Anne M Connolly
- Department of Paediatrics, Neurology Division, Nationwide Children's Hospital, Ohio State University, Columbus, OH, USA
| | - Ulrike Schara
- Department of Paediatric Neurology, Center for Neuromuscular Disorders in Children and Adolescents, University Clinic Essen, University of Duisburg-Essen, Duisburg-Essen, Germany
| | - Andreas Roos
- Department of Paediatric Neurology, Center for Neuromuscular Disorders in Children and Adolescents, University Clinic Essen, University of Duisburg-Essen, Duisburg-Essen, Germany
| | - Mark Tarnopolsky
- Division of Neuromuscular & Neurometabolic Disorders, Department of Paediatrics, McMaster University, Hamilton Health Sciences Centre, Hamilton, Ontario, Canada
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Robert H Brown
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Chia-Hsueh Lee
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Thorsten Hornemann
- Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of Health Sciences, Bethesda, MD, USA.
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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12
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Green CD, Weigel C, Oyeniran C, James BN, Davis D, Mahawar U, Newton J, Wattenberg BW, Maceyka M, Spiegel S. CRISPR/Cas9 deletion of ORMDLs reveals complexity in sphingolipid metabolism. J Lipid Res 2021; 62:100082. [PMID: 33939982 PMCID: PMC8167824 DOI: 10.1016/j.jlr.2021.100082] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 04/16/2021] [Indexed: 12/26/2022] Open
Abstract
The serine palmitoyltransferase (SPT) complex catalyzes the rate-limiting step in the de novo biosynthesis of ceramides, the precursors of sphingolipids. The mammalian ORMDL isoforms (ORMDL1-3) are negative regulators of SPT. However, the roles of individual ORMDL isoforms are unclear. Using siRNA against individual ORMDLs, only single siORMDL3 had modest effects on dihydroceramide and ceramide levels, whereas downregulation of all three ORMDLs induced more pronounced increases. With the CRISPR/Cas9-based genome-editing strategy, we established stable single ORMDL3 KO (ORMDL3-KO) and ORMDL1/2/3 triple-KO (ORMDL-TKO) cell lines to further understand the roles of ORMDL proteins in sphingolipid biosynthesis. While ORMDL3-KO modestly increased dihydroceramide and ceramide levels, ORMDL-TKO cells had dramatic increases in the accumulation of these sphingolipid precursors. SPT activity was increased only in ORMDL-TKO cells. In addition, ORMDL-TKO but not ORMDL3-KO dramatically increased levels of galactosylceramides, glucosylceramides, and lactosylceramides, the elevated N-acyl chain distributions of which broadly correlated with the increases in ceramide species. Surprisingly, although C16:0 is the major sphingomyelin species, it was only increased in ORMDL3-KO, whereas all other N-acyl chain sphingomyelin species were significantly increased in ORMDL-TKO cells. Analysis of sphingoid bases revealed that although sphingosine was only increased 2-fold in ORMDL-TKO cells, levels of dihydrosphingosine, dihydrosphingosine-1-phosphate, and sphingosine-1-phosphate were hugely increased in ORMDL-TKO cells and not in ORMDL3-KO cells. Thus, ORMDL proteins may have a complex, multifaceted role in the biosynthesis and regulation of cellular sphingolipids.
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Affiliation(s)
- Christopher D Green
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Cynthia Weigel
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Clement Oyeniran
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Briana N James
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Deanna Davis
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Usha Mahawar
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Jason Newton
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Binks W Wattenberg
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Michael Maceyka
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, Richmond, VA, USA.
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13
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Rago D, Pedersen CET, Huang M, Kelly RS, Gürdeniz G, Brustad N, Knihtilä H, Lee-Sarwar KA, Morin A, Rasmussen MA, Stokholm J, Bønnelykke K, Litonjua AA, Wheelock CE, Weiss ST, Lasky-Su J, Bisgaard H, Chawes BL. Characteristics and Mechanisms of a Sphingolipid-associated Childhood Asthma Endotype. Am J Respir Crit Care Med 2021; 203:853-863. [PMID: 33535020 DOI: 10.1164/rccm.202008-3206oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rationale: A link among sphingolipids, 17q21 genetic variants, and childhood asthma has been suggested, but the underlying mechanisms and characteristics of such an asthma endotype remain to be elucidated.Objectives: To study the sphingolipid-associated childhood asthma endotype using multiomic data.Methods: We used untargeted liquid chromatography-mass spectrometry plasma metabolomic profiles at the ages of 6 months and 6 years from more than 500 children in the COPSAC2010 (Copenhagen Prospective Studies on Asthma in Childhood) birth cohort focusing on sphingolipids, and we integrated the 17q21 genotype and nasal gene expression of SPT (serine palmitoyl-CoA transferase) (i.e., the rate-limiting enzyme in de novo sphingolipid synthesis) in relation to asthma development and lung function traits from infancy until the age 6 years. Replication was sought in the independent VDAART (Vitamin D Antenatal Asthma Reduction Trial) cohort.Measurements and Main Results: Lower concentrations of ceramides and sphingomyelins at the age of 6 months were associated with an increased risk of developing asthma before age 3, which was also observed in VDAART. At the age of 6 years, lower concentrations of key phosphosphingolipids (e.g., sphinganine-1-phosphate) were associated with increased airway resistance. This relationship was dependent on the 17q21 genotype and nasal SPT gene expression, with significant interactions occurring between the genotype and the phosphosphingolipid concentrations and between the genotype and SPT expression, in which lower phosphosphingolipid concentrations and reduced SPT expression were associated with increasing numbers of at-risk alleles. However, the findings did not pass the false discovery rate threshold of <0.05.Conclusions: This exploratory study suggests the existence of a childhood asthma endotype with early onset and increased airway resistance that is characterized by reduced sphingolipid concentrations, which are associated with 17q21 genetic variants and expression of the SPT enzyme.
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Affiliation(s)
- Daniela Rago
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Casper-Emil T Pedersen
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Mengna Huang
- Channing Division of Network Medicine, Brigham and Women's Hospital-Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Rachel S Kelly
- Channing Division of Network Medicine, Brigham and Women's Hospital-Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Gözde Gürdeniz
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Nicklas Brustad
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Hanna Knihtilä
- Channing Division of Network Medicine, Brigham and Women's Hospital-Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Kathleen A Lee-Sarwar
- Channing Division of Network Medicine, Brigham and Women's Hospital-Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Andréanne Morin
- Department of Human Genetics, University of Chicago, Chicago, Illinois
| | - Morten A Rasmussen
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Jakob Stokholm
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Klaus Bønnelykke
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Augusto A Litonjua
- Division of Pediatric Pulmonary Medicine, Golisano Children's Hospital, University of Rochester Medical Center, Rochester, New York; and
| | - Craig E Wheelock
- Division of Physiological Chemistry II, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Scott T Weiss
- Channing Division of Network Medicine, Brigham and Women's Hospital-Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Jessica Lasky-Su
- Channing Division of Network Medicine, Brigham and Women's Hospital-Harvard Medical School, Harvard University, Boston, Massachusetts
| | - Hans Bisgaard
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
| | - Bo L Chawes
- Copenhagen Prospective Studies on Asthma in Childhood, Herlev and Gentofte Hospital-University of Copenhagen, Gentofte, Denmark
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14
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Structural insights into the regulation of human serine palmitoyltransferase complexes. Nat Struct Mol Biol 2021; 28:240-248. [PMID: 33558761 PMCID: PMC9812531 DOI: 10.1038/s41594-020-00551-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/16/2020] [Indexed: 01/31/2023]
Abstract
Sphingolipids are essential lipids in eukaryotic membranes. In humans, the first and rate-limiting step of sphingolipid synthesis is catalyzed by the serine palmitoyltransferase holocomplex, which consists of catalytic components (SPTLC1 and SPTLC2) and regulatory components (ssSPTa and ORMDL3). However, the assembly, substrate processing and regulation of the complex are unclear. Here, we present 8 cryo-electron microscopy structures of the human serine palmitoyltransferase holocomplex in various functional states at resolutions of 2.6-3.4 Å. The structures reveal not only how catalytic components recognize the substrate, but also how regulatory components modulate the substrate-binding tunnel to control enzyme activity: ssSPTa engages SPTLC2 and shapes the tunnel to determine substrate specificity. ORMDL3 blocks the tunnel and competes with substrate binding through its amino terminus. These findings provide mechanistic insights into sphingolipid biogenesis governed by the serine palmitoyltransferase complex.
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15
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Alsiyabi A, Solis AG, Cahoon EB, Saha R. Dissecting the regulatory roles of ORM proteins in the sphingolipid pathway of plants. PLoS Comput Biol 2021; 17:e1008284. [PMID: 33507896 PMCID: PMC7872301 DOI: 10.1371/journal.pcbi.1008284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 02/09/2021] [Accepted: 12/14/2020] [Indexed: 01/05/2023] Open
Abstract
Sphingolipids are a vital component of plant cellular endomembranes and carry out multiple functional and regulatory roles. Different sphingolipid species confer rigidity to the membrane structure, facilitate trafficking of secretory proteins, and initiate programmed cell death. Although the regulation of the sphingolipid pathway is yet to be uncovered, increasing evidence has pointed to orosomucoid proteins (ORMs) playing a major regulatory role and potentially interacting with a number of components in the pathway, including both enzymes and sphingolipids. However, experimental exploration of new regulatory interactions is time consuming and often infeasible. In this work, a computational approach was taken to address this challenge. A metabolic network of the sphingolipid pathway in plants was reconstructed. The steady-state rates of reactions in the network were then determined through measurements of growth and cellular composition of the different sphingolipids in Arabidopsis seedlings. The Ensemble modeling framework was modified to accurately account for activation mechanisms and subsequently used to generate sets of kinetic parameters that converge to the measured steady-state fluxes in a thermodynamically consistent manner. In addition, the framework was appended with an additional module to automate screening the parameters and to output models consistent with previously reported network responses to different perturbations. By analyzing the network's response in the presence of different combinations of regulatory mechanisms, the model captured the experimentally observed repressive effect of ORMs on serine palmitoyltransferase (SPT). Furthermore, predictions point to a second regulatory role of ORM proteins, namely as an activator of class II (or LOH1 and LOH3) ceramide synthases. This activating role was found to be modulated by the concentration of free ceramides, where an accumulation of these sphingolipid species dampened the activating effect of ORMs on ceramide synthase. The predictions pave the way for future guided experiments and have implications in engineering crops with higher biotic stress tolerance.
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Affiliation(s)
- Adil Alsiyabi
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Ariadna Gonzalez Solis
- Center for Plant Science Innovation & Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Edgar B. Cahoon
- Center for Plant Science Innovation & Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Rajib Saha
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
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16
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Luthers CR, Dunn TM, Snow AL. ORMDL3 and Asthma: Linking Sphingolipid Regulation to Altered T Cell Function. Front Immunol 2020; 11:597945. [PMID: 33424845 PMCID: PMC7793773 DOI: 10.3389/fimmu.2020.597945] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/02/2020] [Indexed: 12/21/2022] Open
Abstract
Orosomucoid like 3 (ORMDL3) encodes an ER-resident transmembrane protein that regulates the activity of serine palmitoyltransferase (SPT), the first and rate-limiting enzyme for sphingolipid biosynthesis in cells. A decade ago, several genome wide association studies revealed single nucleotide polymorphisms associated with increased ORMDL3 protein expression and susceptibility to allergic asthma. Since that time, numerous studies have investigated how altered ORMDL3 expression might predispose to asthma and other autoimmune/inflammatory diseases. In this brief review, we focus on growing evidence suggesting that heightened ORMDL3 expression specifically in CD4+ T lymphocytes, the central orchestrators of adaptive immunity, constitutes a major underlying mechanism of asthma pathogenesis by skewing their differentiation and function. Furthermore, we explore how sphingolipid modulation in T cells might be responsible for these effects, and how further studies may interrogate this intriguing hypothesis.
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Affiliation(s)
- Christopher R Luthers
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Teresa M Dunn
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.,Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Andrew L Snow
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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17
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Expression Patterns and Prognostic Values of ORMDL1 in Different Cancers. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5178397. [PMID: 33145351 PMCID: PMC7596526 DOI: 10.1155/2020/5178397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 08/03/2020] [Accepted: 09/15/2020] [Indexed: 01/13/2023]
Abstract
The mammalian orosomucoid-like gene family (ORMDL), containing ORMDL1, ORMDL2, and ORMDL3, is the important regulator of sphingolipid metabolism, which is relevant to cell growth, proliferation, migration, and invasion. Since the role of ORMDL1 in cancers remained unclear, the main purpose of our study was to explore the expression patterns and prognostic values of ORMDL1 in different tumors, especially in cholangiocarcinoma (CHOL), lymphoid neoplasm diffuse large B cell lymphoma (DLBCL), acute myeloid leukemia (LAML), and thymoma (THYM). Bioinformatics tools including GEPIA, CCLE, LinkedOmics, cBioPortal, and TIMER databases were used. As a result, the expression levels of ORMDL1 in tumor tissues and normal tissues varied in different cancers, especially significantly upregulated in CHOL, DLBCL, LAML, and THYM. Moreover, ORMDL1 mRNA was also highly expressed in cell lines of DLBCL and LAML. Further studies showed that ORMDL1 overexpression was associated with poor prognosis in DLBCL, but not significant in CHOL, LAML, and THYM. Consistently, there were genetic alterations of ORMDL1 in DLBCL, and patients with genetic alterations indicated worse survival. Coexpressed genes and related biological events with ORMDL1 in DLBCL were found via LinkedOmics, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The relationship between ORMDL1 and cancer immune cells was investigated, and ORMDL1 expression was positively correlated with infiltrating levels of B cells. In conclusion, ORMDL1 is suggested to be a tumorigenic factor and considered as the potential therapeutic target and prognostic biomarker in DLBCL.
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18
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Gonzalez-Solis A, Han G, Gan L, Li Y, Markham JE, Cahoon RE, Dunn TM, Cahoon EB. Unregulated Sphingolipid Biosynthesis in Gene-Edited Arabidopsis ORM Mutants Results in Nonviable Seeds with Strongly Reduced Oil Content. THE PLANT CELL 2020; 32:2474-2490. [PMID: 32527862 PMCID: PMC7401009 DOI: 10.1105/tpc.20.00015] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/21/2020] [Accepted: 06/08/2020] [Indexed: 05/03/2023]
Abstract
Orosomucoid-like proteins (ORMs) interact with serine palmitoyltransferase (SPT) to negatively regulate sphingolipid biosynthesis, a reversible process critical for balancing the intracellular sphingolipid levels needed for growth and programmed cell death. Here, we show that ORM1 and ORM2 are essential for life cycle completion in Arabidopsis (Arabidopsis thaliana). Seeds from orm1 -/- orm2 -/- mutants, generated by crossing CRISPR/Cas9 knockout mutants for each gene, accumulated high levels of ceramide, indicative of unregulated sphingolipid biosynthesis. orm1 -/- orm2 -/- seeds were nonviable, displayed aberrant embryo development, and had >80% reduced oil content versus wild-type seeds. This phenotype was mimicked in Arabidopsis seeds expressing the SPT subunit LCB1 lacking its first transmembrane domain, which is critical for ORM-mediated regulation of SPT. We identified a mutant for ORM1 lacking one amino acid (Met-51) near its second transmembrane domain that retained its membrane topology. Expressing this allele in the orm2 background yielded plants that did not advance beyond the seedling stage, hyperaccumulated ceramides, and showed altered organellar structures and increased senescence- and pathogenesis-related gene expression. These seedlings also showed upregulated expression of genes for sphingolipid catabolic enzymes, pointing to additional mechanisms for maintaining sphingolipid homeostasis. ORM1 lacking Met-51 had strongly impaired interactions with LCB1 in a yeast (Saccharomyces cerevisiae) model, providing structural clues about regulatory interactions between ORM and SPT.
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Affiliation(s)
- Ariadna Gonzalez-Solis
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Gongshe Han
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Lu Gan
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Yunfeng Li
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Jennifer E Markham
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Rebecca E Cahoon
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Teresa M Dunn
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Edgar B Cahoon
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
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19
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Majumder S, Kono M, Lee YT, Byrnes C, Li C, Tuymetova G, Proia RL. A genome-wide CRISPR/Cas9 screen reveals that the aryl hydrocarbon receptor stimulates sphingolipid levels. J Biol Chem 2020; 295:4341-4349. [PMID: 32029474 PMCID: PMC7105297 DOI: 10.1074/jbc.ac119.011170] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/28/2020] [Indexed: 01/12/2023] Open
Abstract
Sphingolipid biosynthesis generates lipids for membranes and signaling that are crucial for many developmental and physiological processes. In some cases, large amounts of specific sphingolipids must be synthesized for specialized physiological functions, such as during axon myelination. How sphingolipid synthesis is regulated to fulfill these physiological requirements is not known. To identify genes that positively regulate membrane sphingolipid levels, here we employed a genome-wide CRISPR/Cas9 loss-of-function screen in HeLa cells using selection for resistance to Shiga toxin, which uses a plasma membrane-associated glycosphingolipid, globotriaosylceramide (Gb3), for its uptake. The screen identified several genes in the sphingolipid biosynthetic pathway that are required for Gb3 synthesis, and it also identified the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor widely involved in development and physiology, as being required for Gb3 biosynthesis. AHR bound and activated the gene promoter of serine palmitoyltransferase small subunit A (SPTSSA), which encodes a subunit of the serine palmitoyltransferase that catalyzes the first and rate-limiting step in de novo sphingolipid biosynthesis. AHR knockout HeLa cells exhibited significantly reduced levels of cell-surface Gb3, and both AHR knockout HeLa cells and tissues from Ahr knockout mice displayed decreased sphingolipid content as well as significantly reduced expression of several key genes in the sphingolipid biosynthetic pathway. The sciatic nerve of Ahr knockout mice exhibited both reduced ceramide content and reduced myelin thickness. These results indicate that AHR up-regulates sphingolipid levels and is important for full axon myelination, which requires elevated levels of membrane sphingolipids.
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Affiliation(s)
- Saurav Majumder
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Mari Kono
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Y Terry Lee
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Colleen Byrnes
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Cuiling Li
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Galina Tuymetova
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Richard L Proia
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
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20
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Druggable Sphingolipid Pathways: Experimental Models and Clinical Opportunities. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1274:101-135. [PMID: 32894509 DOI: 10.1007/978-3-030-50621-6_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Intensive research in the field of sphingolipids has revealed diverse roles in cell biological responses and human health and disease. This immense molecular family is primarily represented by the bioactive molecules ceramide, sphingosine, and sphingosine 1-phosphate (S1P). The flux of sphingolipid metabolism at both the subcellular and extracellular levels provides multiple opportunities for pharmacological intervention. The caveat is that perturbation of any single node of this highly regulated flux may have effects that propagate throughout the metabolic network in a dramatic and sometimes unexpected manner. Beginning with S1P, the receptors for which have thus far been the most clinically tractable pharmacological targets, this review will describe recent advances in therapeutic modulators targeting sphingolipids, their chaperones, transporters, and metabolic enzymes.
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21
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Mallela SK, Mitrofanova A, Merscher S, Fornoni A. Regulation of the amount of ceramide-1-phosphate synthesized in differentiated human podocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:158517. [PMID: 31487557 PMCID: PMC6832884 DOI: 10.1016/j.bbalip.2019.158517] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/09/2019] [Accepted: 08/26/2019] [Indexed: 12/14/2022]
Abstract
Sphingolipids have important functions as structural components of cells but they also function as signaling molecules regulating different cellular processes such as apoptosis, cell proliferation, cell migration, cell division and inflammation. Hence, a tight regulation of the sphingolipid homeostasis is essential to maintain proper cellular functions. Mammalian ORMDL proteins are orthologues of the yeast ORM1/2 proteins, which regulate ceramide synthesis in yeast. ORMDL proteins inhibit serine palmitoyltransferase (SPT), the enzyme regulating a rate-limiting step of the sphingolipid pathway to control the levels of ceramides and other sphingolipids. Sphingomyelinase phosphodiesterase like 3b (SMPDL3b) is a glycosylphosphatidylinositol (GPI) anchored protein in the plasma membrane (PM) and determines membrane fluidity in macrophages. We previously showed that differential expression of SMPDL3b alters the availability of Ceramide-1-phosphate (C1P) in human podocytes, which are terminally differentiated cells of the kidney filtration barrier. This observation lead us to investigate if SMPDL3b controls C1P availability in human podocytes by interfering with ceramide kinase (CERK) expression and function. We found that SMPDL3b interacts with CERK and can bind to C1P in vitro. Furthermore, CERK expression is reduced when SMPDL3b expression is silenced. These observations led us to propose that one of the mechanisms by which SMPDL3b influences the amount of C1P available in the podocytes is by interfering with the function of CERK thereby maintaining a balance in the levels of the C1P in podocytes.
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Affiliation(s)
- Shamroop Kumar Mallela
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA.
| | - Alla Mitrofanova
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Sandra Merscher
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA; Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL, USA.
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22
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James B, Milstien S, Spiegel S. ORMDL3 and allergic asthma: From physiology to pathology. J Allergy Clin Immunol 2019; 144:634-640. [PMID: 31376405 DOI: 10.1016/j.jaci.2019.07.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/18/2019] [Accepted: 07/26/2019] [Indexed: 01/10/2023]
Abstract
There is a strong genetic component to asthma, and numerous genome-wide association studies have identified ORM1 (yeast)-like protein 3 (ORMDL3) as a gene associated with asthma susceptibility. However, how ORMDL3 contributes to asthma pathogenesis and its physiologic functions is not well understood and a matter of great debate. This rostrum describes recent advances and new insights in understanding of the multifaceted functions of ORMDL3 in patients with allergic asthma. We also suggest a potential unifying paradigm and discuss molecular mechanisms for the pathologic functions of ORMDL3 in asthma related to its evolutionarily conserved role in regulation of sphingolipid homeostasis. Finally, we briefly survey the utility of sphingolipid metabolites as potential biomarkers for allergic asthma.
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Affiliation(s)
- Briana James
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Sheldon Milstien
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va.
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23
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Harrison PJ, Gable K, Somashekarappa N, Kelly V, Clarke DJ, Naismith JH, Dunn TM, Campopiano DJ. Use of isotopically labeled substrates reveals kinetic differences between human and bacterial serine palmitoyltransferase. J Lipid Res 2019; 60:953-962. [PMID: 30792183 PMCID: PMC6495160 DOI: 10.1194/jlr.m089367] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 02/14/2019] [Indexed: 12/17/2022] Open
Abstract
Isotope labels are frequently used tools to track metabolites through complex biochemical pathways and to discern the mechanisms of enzyme-catalyzed reactions. Isotopically labeled l-serine is often used to monitor the activity of the first enzyme in sphingolipid biosynthesis, serine palmitoyltransferase (SPT), as well as labeling downstream cellular metabolites. Intrigued by the effect that isotope labels may be having on SPT catalysis, we characterized the impact of different l-serine isotopologues on the catalytic activity of recombinant SPT isozymes from humans and the bacterium Sphingomonas paucimobilis Our data show that S. paucimobilis SPT activity displays a clear isotope effect with [2,3,3-D]l-serine, whereas the human SPT isoform does not. This suggests that although both human and S. paucimobilis SPT catalyze the same chemical reaction, there may well be underlying subtle differences in their catalytic mechanisms. Our results suggest that it is the activating small subunits of human SPT that play a key role in these mechanistic variations. This study also highlights that it is important to consider the type and location of isotope labels on a substrate when they are to be used in in vitro and in vivo studies.
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Affiliation(s)
- Peter J Harrison
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom; Division of Structural Biology Wellcome Trust Centre for Human Genomics, Oxford OX3 7BN, United Kingdom; Research Complex at Harwell Rutherford Appleton Laboratory, Didcot OX11 0FA, United Kingdom
| | - Kenneth Gable
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD 20814-4799
| | | | - Van Kelly
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - David J Clarke
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - James H Naismith
- Division of Structural Biology Wellcome Trust Centre for Human Genomics, Oxford OX3 7BN, United Kingdom; Research Complex at Harwell Rutherford Appleton Laboratory, Didcot OX11 0FA, United Kingdom; The Rosalind Franklin Institute Rutherford Appleton Laboratory, Didcot OX11 0FA, United Kingdom
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD 20814-4799
| | - Dominic J Campopiano
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom.
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24
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A Novel Variant (Asn177Asp) in SPTLC2 Causing Hereditary Sensory Autonomic Neuropathy Type 1C. Neuromolecular Med 2019; 21:182-191. [PMID: 30955194 DOI: 10.1007/s12017-019-08534-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 04/01/2019] [Indexed: 12/11/2022]
Abstract
Hereditary sensory and autonomic neuropathy type 1 (HSAN1) is a rare, autosomal dominantly inherited, slowly progressive and length-dependent axonal peripheral neuropathy. HSAN1 is associated with several mutations in serine-palmitoyltransferase (SPT), the first enzyme in the de novo sphingolipid biosynthetic pathway. HSAN1 mutations alter the substrate specificity of SPT, which leads to the formation of 1-deoxysphingolipids, an atypical and neurotoxic subclass of sphingolipids. This study describes the clinical and neurophysiological phenotype of a German family with a novel SPTCL2 mutation (c.529A > G; N177D) associated with HSAN1 and the biochemical characterization of this mutation.) The mutaion was identified in five family members that segregated with the diesease. Patients were characterized genetically and clinically for neurophysiological function. Their plasma sphingolipid profiles were analyzed by LC-MS. The biochemical properties of the mutation were characterized in a cell-based activity assay. Affected family members showed elevated 1-deoxysphingolipid plasma levels. HEK293 cells expressing the N177D SPTLC2 mutant showed increased de novo 1-deoxysphingolipid formation, but also displayed elevated canonical SPT activity and increased C20 sphingoid base production. This study identifies the SPTLC2 N177D variant as a novel disease-causing mutation with increased 1-deoxySL formation and its association with a typical HSAN1 phenotype.
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25
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Davis DL, Gable K, Suemitsu J, Dunn TM, Wattenberg BW. The ORMDL/Orm-serine palmitoyltransferase (SPT) complex is directly regulated by ceramide: Reconstitution of SPT regulation in isolated membranes. J Biol Chem 2019; 294:5146-5156. [PMID: 30700557 DOI: 10.1074/jbc.ra118.007291] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/25/2019] [Indexed: 01/15/2023] Open
Abstract
Sphingolipids compose a lipid family critical for membrane structure as well as intra- and intercellular signaling. De novo sphingolipid biosynthesis is initiated by the enzyme serine palmitoyltransferase (SPT), which resides in the endoplasmic reticulum (ER) membrane. In both yeast and mammalian species, SPT activity is homeostatically regulated through small ER membrane proteins, the Orms in yeast and the ORMDLs in mammalian cells. These proteins form stable complexes with SPT. In yeast, the homeostatic regulation of SPT relies, at least in part, on phosphorylation of the Orms. However, this does not appear to be the case for the mammalian ORMDLs. Here, we accomplished a cell-free reconstitution of the sphingolipid regulation of the ORMDL-SPT complex to probe the underlying regulatory mechanism. Sphingolipid and ORMDL-dependent regulation of SPT was demonstrated in isolated membranes, essentially free of cytosol. This suggests that this regulation does not require soluble cytosolic proteins or small molecules such as ATP. We found that this system is particularly responsive to the pro-apoptotic sphingolipid ceramide and that this response is strictly stereospecific, indicating that ceramide regulates the ORMDL-SPT complex via a specific binding interaction. Yeast membranes harboring the Orm-SPT system also directly responded to sphingolipid, suggesting that yeast cells have, in addition to Orm phosphorylation, an additional Orm-dependent SPT regulatory mechanism. Our results indicate that ORMDL/Orm-mediated regulation of SPT involves a direct interaction of sphingolipid with the membrane-bound components of the SPT-regulatory apparatus.
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Affiliation(s)
- Deanna L Davis
- From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298
| | - Kenneth Gable
- the Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - John Suemitsu
- From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298
| | - Teresa M Dunn
- the Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - Binks W Wattenberg
- From the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, .,the James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky 40202
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26
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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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27
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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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28
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Davis D, Kannan M, Wattenberg B. Orm/ORMDL proteins: Gate guardians and master regulators. Adv Biol Regul 2018; 70:3-18. [PMID: 30193828 DOI: 10.1016/j.jbior.2018.08.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 12/22/2022]
Abstract
Sphingolipids comprise a diverse family of lipids that perform multiple functions in both structure of cellular membranes and intra- and inter-cellular signaling. The diversity of this family is generated by an array of enzymes that produce individual classes and molecular species of family members and enzymes which catabolize those lipids for recycling pathways. However, all of these lipids begin their lives with a single step, the condensation of an amino acid, almost always serine, and a fatty acyl-CoA, almost always the 16-carbon, saturated fatty acid, palmitate. The enzyme complex that accomplishes this condensation is serine palmitoyltransferase (SPT), a membrane-bound component of the endoplasmic reticulum. This places SPT in the unique position of regulating the production of the entire sphingolipid pool. Understanding how SPT activity is regulated is currently a central focus in the field of sphingolipid biology. In this review we examine the regulation of SPT activity by a set of small, membrane-bound proteins of the endoplasmic reticulum, the Orms (in yeast) and ORMDLs (in vertebrates). We discuss what is known about how these proteins act as homeostatic regulators by monitoring cellular levels of sphingolipid, but also how the Orms/ORMDLs regulate SPT in response to other stimuli. Finally, we discuss the intriguing connection between one of the mammalian ORMDL isoforms, ORMDL3, and the pervasive pulmonary disease, asthma, in humans.
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Affiliation(s)
- Deanna Davis
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Muthukumar Kannan
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Binks Wattenberg
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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29
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Grassi S, Chiricozzi E, Mauri L, Sonnino S, Prinetti A. Sphingolipids and neuronal degeneration in lysosomal storage disorders. J Neurochem 2018; 148:600-611. [PMID: 29959861 DOI: 10.1111/jnc.14540] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/25/2018] [Accepted: 06/27/2018] [Indexed: 12/27/2022]
Abstract
Ceramide, sphingomyelin, and glycosphingolipids (both neutral and acidic) are characterized by the presence in the lipid moiety of an aliphatic base known as sphingosine. Altogether, they are called sphingolipids and are particularly abundant in neuronal plasma membranes, where, via interactions with the other membrane lipids and membrane proteins, they play a specific role in modulating the cell signaling processes. The metabolic pathways determining the plasma membrane sphingolipid composition are thus the key point for functional changes of the cell properties. Unnatural changes of the neuronal properties are observed in sphingolipidoses, lysosomal storage diseases occurring when a lysosomal sphingolipid hydrolase is not working, leading to the accumulation of the substrate and to its distribution to all the cell membranes interacting with lysosomes. Moreover, secondary accumulation of sphingolipids is a common trait of other lysosomal storage diseases. This article is part of the Special Issue "Lysosomal Storage Disorders".
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Affiliation(s)
- Sara Grassi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Elena Chiricozzi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Laura Mauri
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Sandro Sonnino
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Alessandro Prinetti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
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Sandhoff R, Sandhoff K. Emerging concepts of ganglioside metabolism. FEBS Lett 2018; 592:3835-3864. [PMID: 29802621 DOI: 10.1002/1873-3468.13114] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 11/12/2022]
Abstract
Gangliosides (GGs) are sialic acid-containing glycosphingolipids (GSLs) and major membrane components enriched on cellular surfaces. Biosynthesis of mammalian GGs starts at the cytosolic leaflet of endoplasmic reticulum (ER) membranes with the formation of their hydrophobic ceramide anchors. After intracellular ceramide transfer to Golgi and trans-Golgi network (TGN) membranes, anabolism of GGs, as well as of other GSLs, is catalyzed by membrane-spanning glycosyltransferases (GTs) along the secretory pathway. Combined activity of only a few promiscuous GTs allows for the formation of cell-type-specific glycolipid patterns. Following an exocytotic vesicle flow to the cellular plasma membranes, GGs can be modified by metabolic reactions at or near the cellular surface. For degradation, GGs are endocytosed to reach late endosomes and lysosomes. Whereas membrane-spanning enzymes of the secretory pathway catalyze GSL and GG formation, a cooperation of soluble glycosidases, lipases and lipid-binding cofactors, namely the sphingolipid activator proteins (SAPs), act as the main players of GG and GSL catabolism at intralysosomal luminal vesicles (ILVs).
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Affiliation(s)
- Roger Sandhoff
- Lipid Pathobiochemistry Group (G131), German Cancer Research Center, Heidelberg, Germany
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Sandhoff R, Schulze H, Sandhoff K. Ganglioside Metabolism in Health and Disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 156:1-62. [DOI: 10.1016/bs.pmbts.2018.01.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Das S, Miller M, Broide DH. Chromosome 17q21 Genes ORMDL3 and GSDMB in Asthma and Immune Diseases. Adv Immunol 2017; 135:1-52. [PMID: 28826527 DOI: 10.1016/bs.ai.2017.06.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chromosome 17q21 contains a cluster of genes including ORMDL3 and GSDMB, which have been highly linked to asthma in genome-wide association studies. ORMDL3 is localized to the endoplasmic reticulum and regulates downstream pathways including sphingolipids, metalloproteases, remodeling genes, and chemokines. ORMDL3 inhibits serine palmitoyl-CoA transferase, the rate-limiting enzyme for sphingolipid biosynthesis. In addition, ORMDL3 activates the ATF6α branch of the unfolded protein response which regulates SERCA2b and IL-6, pathways of potential importance to asthma. The SNP-linking chromosome 17q21 to asthma is associated with increased ORMDL3 and GSDMB expression. Mice expressing either increased levels of human ORMDL3, or human GSDMB, have an asthma phenotype characterized by increased airway responsiveness and increased airway remodeling (increased smooth muscle and fibrosis) in the absence of airway inflammation. GSDMB regulates expression of 5-LO and TGF-β1 which are known pathways involved in the pathogenesis of asthma. GSDMB is one of four members of the GSDM family (GSDMA, GSDMB, GSDMC, and GSDMD). GSDMD (located on chromosome 8q24 and not linked to asthma) has emerged as a key mediator of pyroptosis. GSDMD is a key component of the NLPR3 inflammasome and is required for its activation. GSDMD undergoes proteolytic cleavage by caspase-1 to release its N-terminal fragment, which in turn mediates pyroptosis and IL-1β secretion. Chromosome 17q21 has not only been linked to asthma but also to type 1 diabetes, inflammatory bowel disease, and primary biliary cirrhosis suggesting that future insights into the biology of genes located in this region will increase our understanding of these diseases.
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Affiliation(s)
- Sudipta Das
- University of California, San Diego, CA, United States
| | - Marina Miller
- University of California, San Diego, CA, United States
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Abstract
PURPOSE OF REVIEW Genome-wide association studies identified ORMDL3, a protein of the endoplasmic reticulum, as a significant asthma risk factor. ORMDL3 is one of three ORMDL proteins that integrate multiple signals to maintain sphingolipid homeostasis. Studies that investigated potential mechanisms for how increased ORMDL3 might affect asthma are summarized. RECENT FINDINGS Investigations focused on decreased sphingolipid synthesis and on the unfolded protein response because ORMDL3 had been implicated in both.Airway reactivity is increased in a genetic model with decreased de-novo sphingolipid synthesis and in wild-type mice treated with myriocin, a sphingolipid synthesis inhibitor. Inflammation, mucus production and airway smooth muscle hypertrophy are absent. ORMDL3 was not evaluated directly but results suggest that decreased sphingolipid synthesis is sufficient to induce airway hyperreactivity (AHR).Direct effects of ORMDL3 were investigated in allergic asthma models. Sensitization with ovalbumin, house dust mites and Alternaria alternata increase ORMDL3 mRNA. Universal overexpression of ORMDL3 decreases serum sphingolipids, increases inflammatory markers, airway remodeling and AHR in response to allergic stimuli. Addition of myriocin during sensitization drastically exacerbates house dust mites-induced AHR.ORMDL3 knockout mice are protected from developing A. alternata-induced AHR. The effect is specific to Alternaria and limited to smooth muscle contraction, as inflammation persists. ORMDL3 might have a critical role for smooth muscle contraction.Little is known about how the different ORMDL3 single nucleotide polymorphisms affect human blood and tissue sphingolipid profiles. One group measured total sphingoid levels and found no association with ORMDL3 single nucleotide polymorphisms in a general population. Others evaluated sphingolipid profiles in 7-8-year old children with mild asthma and found significantly higher C18 and C20 ceramides in those with persistence of asthma symptoms 3 years later, suggesting that sphingolipid profiles might predict asthma persistence. SUMMARY Possible mechanisms how ORMDL3 affects asthma include inhibition of sphingolipid synthesis, synergistic effects with known allergens and a combination of both.
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Affiliation(s)
- Tilla S Worgall
- Columbia University Medical Center, New York City, New York, USA
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Maekawa M, Lee M, Wei K, Ridgway ND, Fairn GD. Staurosporines decrease ORMDL proteins and enhance sphingomyelin synthesis resulting in depletion of plasmalemmal phosphatidylserine. Sci Rep 2016; 6:35762. [PMID: 27805006 PMCID: PMC5090970 DOI: 10.1038/srep35762] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/05/2016] [Indexed: 12/03/2022] Open
Abstract
Accumulation of phosphatidylserine in the inner leaflet of the plasma membrane is a hallmark of eukaryotes. Sublethal levels of staurosporine and related compounds deplete phosphatidylserine from the plasma membrane and abrogate K-Ras signaling. Here, we report that low-dose staurosporine and related compounds increase sphingomyelin mass. Mass-spectrometry and metabolic tracer analysis revealed an increase in both the levels and rate of synthesis of sphingomyelin in response to sublethal staurosporine. Mechanistically, it was determined that the abundance of the ORMDL proteins, which negatively regulate serine-palmitoyltransferase, are decreased by low-dose staurosporine. Finally, inhibition of ceramide synthesis, and thus sphingomyelin, prevented the displacement of phosphatidylserine and cholesterol from the inner leaflet of the plasma membrane. The results establish that an optimal level of sphingomyelin is required to maintain the distribution of phosphatidylserine and cholesterol in the plasma membrane and further demonstrate a complex relationship between the trafficking of phosphatidylserine and sphingomyelin.
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Affiliation(s)
- Masashi Maekawa
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Minhyoung Lee
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Kuiru Wei
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Neale D Ridgway
- Departments of Pediatrics, and Biochemistry &Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Surgery, University of Toronto, Toronto, ON, Canada
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35
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Paulenda T, Draber P. The role of ORMDL proteins, guardians of cellular sphingolipids, in asthma. Allergy 2016; 71:918-30. [PMID: 26969910 DOI: 10.1111/all.12877] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2016] [Indexed: 12/29/2022]
Abstract
A family of widely expressed ORM-like (ORMDL) proteins has been recently linked to asthma in genomewide association studies in humans and extensively explored in in vivo studies in mice. ORMDL proteins are key regulators of serine palmitoyltransferase, an enzyme catalyzing the initial step of sphingolipid biosynthesis. Sphingolipids play prominent roles in cell signaling and response to stress, and they affect the mechanistic properties of cellular membranes. Deregulation of sphingolipid biosynthesis and their recycling has been proven to support and even cause several diseases including allergy, inflammation, and asthma. ORMDL3, the most extensively studied member of the ORMDL family, has been shown to be important for endoplasmic reticulum homeostasis by regulating the unfolded protein response and calcium response. In immune cells, ORMDL3 is involved in migration and in the production of proinflammatory cytokines. Furthermore, changes in the expression level of ORMDL3 are important in allergen-induced asthma pathologies. This review focuses on functional aspects of the ORMDL family proteins, which may serve as new therapeutic targets for the treatment of asthma and some other life-threatening diseases.
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Affiliation(s)
- T. Paulenda
- Laboratory of Signal Transduction; Institute of Molecular Genetics; Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - P. Draber
- Laboratory of Signal Transduction; Institute of Molecular Genetics; Academy of Sciences of the Czech Republic; Prague Czech Republic
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Cai L, Oyeniran C, Biswas DD, Allegood J, Milstien S, Kordula T, Maceyka M, Spiegel S. ORMDL proteins regulate ceramide levels during sterile inflammation. J Lipid Res 2016; 57:1412-22. [PMID: 27313060 DOI: 10.1194/jlr.m065920] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Indexed: 12/21/2022] Open
Abstract
The bioactive sphingolipid metabolite, ceramide, regulates physiological processes important for inflammation and elevated levels of ceramide have been implicated in IL-1-mediated events. Although much has been learned about ceramide generation by activation of sphingomyelinases in response to IL-1, the contribution of the de novo pathway is not completely understood. Because yeast ORM1 and ORM2 proteins negatively regulate ceramide levels through inhibition of serine palmitoyltransferase, the first committed step in ceramide biosynthesis, we examined the functions of individual mammalian ORM orthologs, ORM (yeast)-like (ORMDL)1-3, in regulation of ceramide levels. In HepG2 liver cells, downregulation of ORMDL3 markedly increased the ceramide precursors, dihydrosphingosine and dihydroceramide, primarily from de novo biosynthesis based on [U-(13)C]palmitate incorporation into base-labeled and dual-labeled dihydroceramides, whereas downregulation of each isoform increased dihydroceramides [(13)C]labeled in only the amide-linked fatty acid. IL-1 and the IL-6 family cytokine, oncostatin M, increased dihydroceramide and ceramide levels in HepG2 cells and concomitantly decreased ORMDL proteins. Moreover, during irritant-induced sterile inflammation in mice leading to induction of the acute-phase response, which is dependent on IL-1, expression of ORMDL proteins in the liver was strongly downregulated and accompanied by increased ceramide levels in the liver and accumulation in the blood. Together, our results suggest that ORMDLs may be involved in regulation of ceramides during IL-1-mediated sterile inflammation.
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Affiliation(s)
- Lin Cai
- School of Pharmacy, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Clement Oyeniran
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Debolina D Biswas
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Jeremy Allegood
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Sheldon Milstien
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Tomasz Kordula
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Michael Maceyka
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
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Bode H, Bourquin F, Suriyanarayanan S, Wei Y, Alecu I, Othman A, Von Eckardstein A, Hornemann T. HSAN1 mutations in serine palmitoyltransferase reveal a close structure-function-phenotype relationship. Hum Mol Genet 2015; 25:853-65. [PMID: 26681808 DOI: 10.1093/hmg/ddv611] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/12/2015] [Indexed: 12/13/2022] Open
Abstract
Hereditary sensory and autonomic neuropathy type 1 (HSAN1) is a rare autosomal dominant inherited peripheral neuropathy caused by mutations in the SPTLC1 and SPTLC2 subunits of serine palmitoyltransferase (SPT). The mutations induce a permanent shift in the substrate preference from L-serine to L-alanine, which results in the pathological formation of atypical and neurotoxic 1-deoxy-sphingolipids (1-deoxySL). Here we compared the enzymatic properties of 11 SPTLC1 and six SPTLC2 mutants using a uniform isotope labelling approach. In total, eight SPT mutants (STPLC1p.C133W, p.C133Y, p.S331F, p.S331Y and SPTLC2p.A182P, p.G382V, p.S384F, p.I504F) were associated with increased 1-deoxySL synthesis. Despite earlier reports, canonical activity with l-serine was not reduced in any of the investigated SPT mutants. Three variants (SPTLC1p.S331F/Y and SPTLC2p.I505Y) showed an increased canonical activity and increased formation of C20 sphingoid bases. These three mutations are associated with an exceptionally severe HSAN1 phenotype, and increased C20 sphingosine levels were also confirmed in plasma of patients. A principal component analysis of the analysed sphingoid bases clustered the mutations into three separate entities. Each cluster was related to a distinct clinical outcome (no, mild and severe HSAN1 phenotype). A homology model based on the protein structure of the prokaryotic SPT recapitulated the same grouping on a structural level. Mutations associated with the mild form clustered around the active site, whereas mutations associated with the severe form were located on the surface of the protein. In conclusion, we showed that HSAN1 mutations in SPT have distinct biochemical properties, which allowed for the prediction of the clinical symptoms on the basis of the plasma sphingoid base profile.
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Affiliation(s)
- Heiko Bode
- Institute for Clinical Chemistry, University Hospital Zurich, Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Florence Bourquin
- Institute of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Saranya Suriyanarayanan
- Institute for Clinical Chemistry, University Hospital Zurich, Competence Center for Personalized Medicine (CC-PM), Molecular Translation and Biomedicine (MTB), and
| | - Yu Wei
- Institute for Clinical Chemistry, University Hospital Zurich
| | - Irina Alecu
- Institute for Clinical Chemistry, University Hospital Zurich, Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Alaa Othman
- Institute for Clinical Chemistry, University Hospital Zurich, Competence Center for Personalized Medicine (CC-PM), Molecular Translation and Biomedicine (MTB), and
| | - Arnold Von Eckardstein
- Institute for Clinical Chemistry, University Hospital Zurich, Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, Competence Center for Personalized Medicine (CC-PM), Molecular Translation and Biomedicine (MTB), and
| | - Thorsten Hornemann
- Institute for Clinical Chemistry, University Hospital Zurich, Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, Competence Center for Personalized Medicine (CC-PM), Molecular Translation and Biomedicine (MTB), and
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Abstract
Glycosphingolipids (GSLs) are a family of bioactive lipids that in addition to their role in the regulation of structural properties of membrane bilayers have emerged as crucial players in many biological processes and signal transduction pathways. Rather than being uniformly distributed within membrane bilayers, GSLs are localized in selective domains called lipid rafts where many signaling platforms operate. One of the most important functions of GSLs, particularly ceramide, is their ability to regulate cell death pathways and hence cell fate. This complex role is accomplished by the ability of GSLs to act in distinct subcellular strategic centers, such as mitochondria, endoplasmic reticulum (ER) or lysosomes to mediate apoptosis, ER stress, autophagy, lysosomal membrane permeabilization and necroptosis. Hence better understanding the role of GSLs in cell death may be of relevance for a number of pathological processes and diseases, including neurodegeneration, metabolic liver diseases and cancer.
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Ono JG, Worgall TS, Worgall S. Airway reactivity and sphingolipids-implications for childhood asthma. Mol Cell Pediatr 2015; 2:13. [PMID: 26637347 PMCID: PMC4670439 DOI: 10.1186/s40348-015-0025-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/25/2015] [Indexed: 01/05/2023] Open
Abstract
Asthma is a clinically heterogeneous disorder, whose onset and progression results from a complex interplay between genetic susceptibility, allergens, and viral triggers. Sphingolipids and altered sphingolipid metabolism have emerged as potential key contributors to the pathogenesis of asthma. Orosomucoid-like 3 gene (ORMDL3) and the asthma susceptibility locus 17q21 have been strongly and reproducibly linked to childhood asthma, but how this gene is functionally linked to asthma is incompletely understood. ORMDL proteins play an integral role in sphingolipid homeostasis and synthesis, and asthma-associated ORMDL3 polymorphisms have been associated with early viral respiratory infections and increased risk of asthma. ORMDL proteins act as inhibitors of serine palmitoyl-CoA transferase (SPT), the rate-limiting enzyme for de novo sphingolipid synthesis, and decreased sphingolipid synthesis through SPT increases airway hyperreactivity, which is independent of allergy or inflammation. In allergic models of asthma, the sphingolipid mediators sphingosine-1-phosphate (S1P) and ceramide have been shown to be important signaling molecules for airway hyperreactivity, mast cell activation, and inflammation. This review will highlight how sphingolipids and altered sphingolipid metabolism may contribute towards the underlying mechanisms of childhood asthma.
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Affiliation(s)
- Jennie G Ono
- Department of Pediatrics, Weill Cornell Medical College, 505 East 70th Street, Box 211, New York, NY, 10021, USA
| | - Tilla S Worgall
- Department of Pathology, Columbia University, New York, NY, USA
| | - Stefan Worgall
- Department of Pediatrics, Weill Cornell Medical College, 505 East 70th Street, Box 211, New York, NY, 10021, USA. .,Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA.
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40
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Oyeniran C, Sturgill JL, Hait NC, Huang WC, Avni D, Maceyka M, Newton J, Allegood JC, Montpetit A, Conrad DH, Milstien S, Spiegel S. Aberrant ORM (yeast)-like protein isoform 3 (ORMDL3) expression dysregulates ceramide homeostasis in cells and ceramide exacerbates allergic asthma in mice. J Allergy Clin Immunol 2015; 136:1035-46.e6. [PMID: 25842287 PMCID: PMC4591101 DOI: 10.1016/j.jaci.2015.02.031] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 01/28/2015] [Accepted: 02/27/2015] [Indexed: 12/21/2022]
Abstract
BACKGROUND Asthma, a chronic inflammatory condition defined by episodic shortness of breath with expiratory wheezing and cough, is a serious health concern affecting more than 250 million persons. Genome-wide association studies have identified ORM (yeast)-like protein isoform 3 (ORMDL3) as a gene associated with susceptibility to asthma. Although its yeast ortholog is a negative regulator of de novo ceramide biosynthesis, how ORMDL3 contributes to asthma pathogenesis is not known. OBJECTIVES We sought to decipher the molecular mechanism for the pathologic functions of ORMDL3 in asthma and the relationship to its evolutionarily conserved role in regulation of ceramide homeostasis. METHODS We determined the relationship between expression of ORMDL3 and ceramide in epithelial and inflammatory cells and in asthma pathogenesis in mice. RESULTS Although small increases in ORMDL3 expression decrease ceramide levels, remarkably, higher expression in lung epithelial cells and macrophages in vitro and in vivo increased ceramide production, which promoted chronic inflammation, airway hyperresponsiveness, and mucus production during house dust mite-induced allergic asthma. Moreover, nasal administration of the immunosuppressant drug FTY720/fingolimod reduced ORMDL3 expression and ceramide levels and mitigated airway inflammation and hyperreactivity and mucus hypersecretion in house dust mite-challenged mice. CONCLUSIONS Our findings demonstrate that overexpression of ORMDL3 regulates ceramide homeostasis in cells in a complex manner and suggest that local FTY720 administration might be a useful therapeutic intervention for the control of allergic asthma.
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Affiliation(s)
- Clement Oyeniran
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Jamie L Sturgill
- Department of Microbiology & Immunology, Virginia Commonwealth University School of Medicine, Richmond, Va; School of Nursing, Virginia Commonwealth University, Richmond, Va
| | - Nitai C Hait
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Wei-Ching Huang
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Dorit Avni
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Michael Maceyka
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Jason Newton
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Jeremy C Allegood
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Alison Montpetit
- School of Nursing, Virginia Commonwealth University, Richmond, Va
| | - Daniel H Conrad
- Department of Microbiology & Immunology, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Sheldon Milstien
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Va.
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Duan J, Merrill AH. 1-Deoxysphingolipids Encountered Exogenously and Made de Novo: Dangerous Mysteries inside an Enigma. J Biol Chem 2015; 290:15380-15389. [PMID: 25947379 PMCID: PMC4505451 DOI: 10.1074/jbc.r115.658823] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The traditional backbones of mammalian sphingolipids are 2-amino, 1,3-diols made by serine palmitoyltransferase (SPT). Many organisms additionally produce non-traditional, cytotoxic 1-deoxysphingoid bases and, surprisingly, mammalian SPT biosynthesizes some of them, too (e.g. 1-deoxysphinganine from l-alanine). These are rapidly N-acylated to 1-deoxy-“ceramides” with very uncommon biophysical properties. The functions of 1-deoxysphingolipids are not known, but they are certainly dangerous as contributors to sensory and autonomic neuropathies when elevated by inherited SPT mutations, and they are noticeable in diabetes, non-alcoholic steatohepatitis, serine deficiencies, and other diseases. As components of food as well as endogenously produced, these substances are mysteries within an enigma.
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Affiliation(s)
- Jingjing Duan
- Schools of Biology and Chemistry & Biochemistry, and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Alfred H Merrill
- Schools of Biology and Chemistry & Biochemistry, and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332.
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42
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Siow D, Sunkara M, Dunn TM, Morris AJ, Wattenberg B. ORMDL/serine palmitoyltransferase stoichiometry determines effects of ORMDL3 expression on sphingolipid biosynthesis. J Lipid Res 2015; 56:898-908. [PMID: 25691431 DOI: 10.1194/jlr.m057539] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The ORM1 (Saccharomyces cerevisiae)-like proteins (ORMDLs) and their yeast orthologs, the Orms, are negative homeostatic regulators of the initiating enzyme in sphingolipid biosynthesis, serine palmitoyltransferase (SPT). Genome-wide association studies have established a strong correlation between elevated expression of the endoplasmic reticulum protein ORMDL3 and risk for childhood asthma. Here we test the notion that elevated levels of ORMDL3 decrease sphingolipid biosynthesis. This was tested in cultured human bronchial epithelial cells (HBECs) (an immortalized, but untransformed, airway epithelial cell line) and in HeLa cells (a cervical adenocarcinoma cell line). Surprisingly, elevated ORMDL3 expression did not suppress de novo biosynthesis of sphingolipids. We determined that ORMDL is expressed in functional excess relative to SPT at normal levels of expression. ORMDLs and SPT form stable complexes that are not increased by elevated ORMDL3 expression. Although sphingolipid biosynthesis was not decreased by elevated ORMDL3 expression, the steady state mass levels of all major sphingolipids were marginally decreased by low level ORMDL3 over-expression in HBECs. These data indicate that the contribution of ORMDL3 to asthma risk may involve changes in sphingolipid metabolism, but that the connection is complex.
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Affiliation(s)
- Deanna Siow
- James Graham Brown Cancer Center University of Louisville School of Medicine, Louisville, KY 40202
| | - Manjula Sunkara
- Division of Cardiovascular Medicine, Gill Heart Institute, University of Kentucky Lexington and Department of Veterans Affairs Medical Center, Lexington, KY 40536
| | - Teresa M Dunn
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD 20184
| | - Andrew J Morris
- Division of Cardiovascular Medicine, Gill Heart Institute, University of Kentucky Lexington and Department of Veterans Affairs Medical Center, Lexington, KY 40536
| | - Binks Wattenberg
- James Graham Brown Cancer Center University of Louisville School of Medicine, Louisville, KY 40202 Departments of Medicine, Biochemistry, and Molecular Biology, Pharmacology, and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202
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