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Li G, Kidd J, Gehr TWB, Li PL. Podocyte Sphingolipid Signaling in Nephrotic Syndrome. Cell Physiol Biochem 2021; 55:13-34. [PMID: 33861526 PMCID: PMC8193717 DOI: 10.33594/000000356] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2021] [Indexed: 11/25/2022] Open
Abstract
Podocytes play a vital role in the pathogenesis of nephrotic syndrome (NS), which is clinically characterized by heavy proteinuria, hypoalbuminemia, hyperlipidemia, and peripheral edema. The pathogenesis of NS has evolved through several hypotheses ranging from immune dysregulation theory and increased glomerular permeability theory to the current concept of podocytopathy. Podocytopathy is characterized by dysfunction or depletion of podocytes, which may be caused by unknown permeability factor, genetic disorders, drugs, infections, systemic disorders, and hyperfiltration. Over the last two decades, numerous studies have been done to explore the molecular mechanisms of podocyte injuries or NS and to develop the novel therapeutic strategies targeting podocytopathy for treatment of NS. Recent studies have shown that normal sphingolipid metabolism is essential for structural and functional integrity of podocytes. As a basic component of the plasma membrane, sphingolipids not only support the assembly of signaling molecules and interaction of receptors and effectors, but also mediate various cellular activities, such as apoptosis, proliferation, stress responses, necrosis, inflammation, autophagy, senescence, and differentiation. This review briefly summarizes current evidence demonstrating the regulation of sphingolipid metabolism in podocytes and the canonical or noncanonical roles of podocyte sphingolipid signaling in the pathogenesis of NS and associated therapeutic strategies.
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Affiliation(s)
- Guangbi Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Jason Kidd
- Division of Nephrology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Todd W B Gehr
- Division of Nephrology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA,
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Alshaker H, Srivats S, Monteil D, Wang Q, Low CMR, Pchejetski D. Field template-based design and biological evaluation of new sphingosine kinase 1 inhibitors. Breast Cancer Res Treat 2018; 172:33-43. [PMID: 30043096 PMCID: PMC6208908 DOI: 10.1007/s10549-018-4900-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 07/19/2018] [Indexed: 11/29/2022]
Abstract
Purpose Sphingosine kinase 1 (SK1) is a protooncogenic enzyme expressed in many human tumours and is associated with chemoresistance and poor prognosis. It is a potent therapy target and its inhibition chemosensitises solid tumours. Despite recent advances in SK1 inhibitors synthesis and validation, their clinical safety and chemosensitising options are not well described. In this study, we have designed, synthesised and tested a new specific SK1 inhibitor with a low toxicity profile. Methods Field template molecular modelling was used for compound design. Lead compounds were tested in cell and mouse cancer models. Results Field template analysis of three known SK1 inhibitors, SKI-178, 12aa and SK1-I, was performed and compound screening identified six potential new SK1 inhibitors. SK1 activity assays in both cell-free and in vitro settings showed that two compounds were effective SK1 inhibitors. Compound SK-F has potently decreased cancer cell viability in vitro and sensitised mouse breast tumours to docetaxel (DTX) in vivo, without significant whole-body toxicity. Conclusion Through field template screening, we have identified a new SK1 inhibitor, SK-F, which demonstrated antitumour activity in vitro and in vivo without overt toxicity when combined with DTX. Electronic supplementary material The online version of this article (10.1007/s10549-018-4900-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Heba Alshaker
- School of Medicine, University of East Anglia, 2.53 BCRE, Norwich Research Park, Norwich, NR47UQ, UK. .,Department of Pharmacology and Biomedical Sciences, Faculty of Pharmacy and Medical Sciences, University of Petra, Amman, Jordan.
| | - Shyam Srivats
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Danielle Monteil
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Qi Wang
- School of Medicine, University of East Anglia, 2.53 BCRE, Norwich Research Park, Norwich, NR47UQ, UK
| | | | - Dmitri Pchejetski
- School of Medicine, University of East Anglia, 2.53 BCRE, Norwich Research Park, Norwich, NR47UQ, UK.
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Morris TG, Borland SJ, Clarke CJ, Wilson C, Hannun YA, Ohanian V, Canfield AE, Ohanian J. Sphingosine 1-phosphate activation of ERM contributes to vascular calcification. J Lipid Res 2017; 59:69-78. [PMID: 29167409 DOI: 10.1194/jlr.m079731] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/11/2017] [Indexed: 02/07/2023] Open
Abstract
Vascular calcification is the deposition of mineral in the artery wall by vascular smooth muscle cells (VSMCs) in response to pathological stimuli. The process is similar to bone formation and is an independent risk factor for cardiovascular disease. Given that ceramide and sphingosine 1-phosphate (S1P) are involved in cardiovascular pathophysiology and biomineralization, their role in VSMC matrix mineralization was investigated. During phosphate-induced VSMC mineralization, endogenous S1P levels increased accompanied by increased sphingosine kinase (SK) activity and increased mRNA expression of SK1 and SK2. Consistent with this, mineralization was increased by exogenous S1P, but decreased by C2-ceramide. Mechanistically, exogenous S1P stimulated ezrin-radixin-moesin (ERM) phosphorylation in VSMCs and ERM phosphorylation was increased concomitantly with endogenous S1P during mineralization. Moreover, inhibition of acid sphingomyelinase and ceramidase with desipramine prevented increased S1P levels, ERM activation, and mineralization. Finally, pharmacological inhibition of ERM phosphorylation with NSC663894 decreased mineralization induced by phosphate and exogenous S1P. Although further studies will be needed to verify these findings in vivo, this study defines a novel role for the SK-S1P-ERM pathways in phosphate-induced VSMC matrix mineralization and shows that blocking these pathways with pharmacological inhibitors reduces mineralization. These results may inform new therapeutic approaches to inhibit or delay vascular calcification.
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Affiliation(s)
- Thomas G Morris
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Samantha J Borland
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Christopher J Clarke
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY
| | - Claire Wilson
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Yusuf A Hannun
- Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY
| | - Vasken Ohanian
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Ann E Canfield
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Jacqueline Ohanian
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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4
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Kwong EK, Li X, Hylemon PB, Zhou H. Sphingosine Kinases/Sphingosine 1-Phosphate Signaling in Hepatic Lipid Metabolism. ACTA ACUST UNITED AC 2017; 3:176-183. [PMID: 29130028 DOI: 10.1007/s40495-017-0093-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ever-increasing prevalence of metabolic diseases such as dyslipidemia and diabetes in the western world continues to be of great public health concern. Biologically active sphingolipids, such as sphingosine 1-phosphate (S1P) and ceramide, are important regulators of lipid metabolism. S1P not only directly functions as an active intracellular mediator, but also activates multiple signaling pathways via five transmembrane G-protein coupled receptors (GPCRs), S1PR1-5. S1P is exclusively formed by sphingosine kinases (SphKs). Two isoforms of SphKs, SphK1 and SphK2, have been identified. Recent identification of the conjugated bile acid-induced activation of S1PR2 as a key regulator of SphK2 opened new directions for both the sphingolipid and bile acid research fields. The role of SphKs/S1P-mediated signaling pathways in health and various human diseases has been extensively reviewed elsewhere. This review focuses on recent findings related to SphKs/S1P-medaited signaling pathways in regulating hepatic lipid metabolism.
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Affiliation(s)
- Eric K Kwong
- Department of Microbiology and Immunology, Medical College of Virginia Campus, McGuire Veterans Affairs Medical Center, Virginia Commonwealth University, Richmond, Virginia, 23298
| | - Xiaojiaoyang Li
- Department of Microbiology and Immunology, Medical College of Virginia Campus, McGuire Veterans Affairs Medical Center, Virginia Commonwealth University, Richmond, Virginia, 23298
| | - Phillip B Hylemon
- Department of Microbiology and Immunology, Medical College of Virginia Campus, McGuire Veterans Affairs Medical Center, Virginia Commonwealth University, Richmond, Virginia, 23298
| | - Huiping Zhou
- Department of Microbiology and Immunology, Medical College of Virginia Campus, McGuire Veterans Affairs Medical Center, Virginia Commonwealth University, Richmond, Virginia, 23298
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Zimmermann H. Extracellular ATP and other nucleotides-ubiquitous triggers of intercellular messenger release. Purinergic Signal 2015; 12:25-57. [PMID: 26545760 DOI: 10.1007/s11302-015-9483-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 10/29/2015] [Indexed: 12/21/2022] Open
Abstract
Extracellular nucleotides, and ATP in particular, are cellular signal substances involved in the control of numerous (patho)physiological mechanisms. They provoke nucleotide receptor-mediated mechanisms in select target cells. But nucleotides can considerably expand their range of action. They function as primary messengers in intercellular communication by stimulating the release of other extracellular messenger substances. These in turn activate additional cellular mechanisms through their own receptors. While this applies also to other extracellular messengers, its omnipresence in the vertebrate organism is an outstanding feature of nucleotide signaling. Intercellular messenger substances released by nucleotides include neurotransmitters, hormones, growth factors, a considerable variety of other proteins including enzymes, numerous cytokines, lipid mediators, nitric oxide, and reactive oxygen species. Moreover, nucleotides activate or co-activate growth factor receptors. In the case of hormone release, the initially paracrine or autocrine nucleotide-mediated signal spreads through to the entire organism. The examples highlighted in this commentary suggest that acting as ubiquitous triggers of intercellular messenger release is one of the major functional roles of extracellular nucleotides. While initiation of messenger release by nucleotides has been unraveled in many contexts, it may have been overlooked in others. It can be anticipated that additional nucleotide-driven messenger functions will be uncovered with relevance for both understanding physiology and development of therapy.
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Affiliation(s)
- Herbert Zimmermann
- Institute of Cell Biology and Neuroscience, Molecular and Cellular Neurobiology, Goethe University, Max-von-Laue-Str. 13, Frankfurt am Main, Germany.
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Li J, Bi FC, Yin J, Wu JX, Rong C, Wu JL, Yao N. An Arabidopsis neutral ceramidase mutant ncer1 accumulates hydroxyceramides and is sensitive to oxidative stress. FRONTIERS IN PLANT SCIENCE 2015; 6:460. [PMID: 26150824 PMCID: PMC4473688 DOI: 10.3389/fpls.2015.00460] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 06/08/2015] [Indexed: 05/18/2023]
Abstract
Ceramidases hydrolyze ceramide into sphingosine and fatty acids and, although ceramidases function as key regulators of sphingolipid homeostasis in mammals, their roles in plants remain largely unknown. Here, we characterized the Arabidopsis thaliana ceramidase AtNCER1, a homolog of human neutral ceramidase. AtNCER1 localizes predominantly on the endoplasmic reticulum. The ncer1 T-DNA insertion mutants had no visible phenotype, but accumulated hydroxyceramides, and showed increased sensitivity to oxidative stress induced by methyl viologen. Plants over-expressing AtNCER1 showed increased tolerance to oxidative stress. These data indicate that the Arabidopsis neutral ceramidase affects sphingolipid homeostasis and oxidative stress responses.
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Affiliation(s)
- Jian Li
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
| | - Fang-Cheng Bi
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences, GuangzhouChina
| | - Jian Yin
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
| | - Jian-Xin Wu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
| | - Chan Rong
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
| | - Jia-Li Wu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
| | - Nan Yao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, GuangzhouChina
- *Correspondence: Nan Yao, State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China,
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Merscher S, Fornoni A. Podocyte pathology and nephropathy - sphingolipids in glomerular diseases. Front Endocrinol (Lausanne) 2014; 5:127. [PMID: 25126087 PMCID: PMC4115628 DOI: 10.3389/fendo.2014.00127] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/14/2014] [Indexed: 01/10/2023] Open
Abstract
Sphingolipids are components of the lipid rafts in plasma membranes, which are important for proper function of podocytes, a key element of the glomerular filtration barrier. Research revealed an essential role of sphingolipids and sphingolipid metabolites in glomerular disorders of genetic and non-genetic origin. The discovery that glucocerebrosides accumulate in Gaucher disease in glomerular cells and are associated with clinical proteinuria initiated intensive research into the function of other sphingolipids in glomerular disorders. The accumulation of sphingolipids in other genetic diseases including Tay-Sachs, Sandhoff, Fabry, hereditary inclusion body myopathy 2, Niemann-Pick, and nephrotic syndrome of the Finnish type and its implications with respect to glomerular pathology will be discussed. Similarly, sphingolipid accumulation occurs in glomerular diseases of non-genetic origin including diabetic kidney disease (DKD), HIV-associated nephropathy, focal segmental glomerulosclerosis (FSGS), and lupus nephritis. Sphingomyelin metabolites, such as ceramide, sphingosine, and sphingosine-1-phosphate have also gained tremendous interest. We recently described that sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b) is expressed in podocytes where it modulates acid sphingomyelinase activity and acts as a master modulator of danger signaling. Decreased SMPDL3b expression in post-reperfusion kidney biopsies from transplant recipients with idiopathic FSGS correlates with the recurrence of proteinuria in patients and in experimental models of xenotransplantation. Increased SMPDL3b expression is associated with DKD. The consequences of differential SMPDL3b expression in podocytes in these diseases with respect to their pathogenesis will be discussed. Finally, the role of sphingolipids in the formation of lipid rafts in podocytes and their contribution to the maintenance of a functional slit diaphragm in the glomerulus will be discussed.
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Affiliation(s)
- Sandra Merscher
- Peggy and Harold Katz Family Drug Discovery Center and Division of Nephrology, Department of Medicine, University of Miami, Miami, FL, USA
- *Correspondence: Sandra Merscher, Peggy and Harold Katz Family Drug Discovery Center and Division of Nephrology, Department of Medicine, University of Miami, 1580 NW 10th Avenue, Batchelor Building, Room 628, Miami, FL 33136, USA e-mail: ; Alessia Fornoni, Peggy and Harold Katz Family Drug Discovery Center and Division of Nephrology, Department of Medicine, University of Miami, 1580 NW 10th Avenue, Batchelor Building, Room 633, Miami, FL 33136, USA e-mail:
| | - Alessia Fornoni
- Peggy and Harold Katz Family Drug Discovery Center and Division of Nephrology, Department of Medicine, University of Miami, Miami, FL, USA
- *Correspondence: Sandra Merscher, Peggy and Harold Katz Family Drug Discovery Center and Division of Nephrology, Department of Medicine, University of Miami, 1580 NW 10th Avenue, Batchelor Building, Room 628, Miami, FL 33136, USA e-mail: ; Alessia Fornoni, Peggy and Harold Katz Family Drug Discovery Center and Division of Nephrology, Department of Medicine, University of Miami, 1580 NW 10th Avenue, Batchelor Building, Room 633, Miami, FL 33136, USA e-mail:
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Sphingosine Phosphate Lyase Regulates Murine Embryonic Stem Cell Proliferation and Pluripotency through an S1P 2/STAT3 Signaling Pathway. Biomolecules 2013; 3:351-368. [PMID: 24619572 PMCID: PMC3947625 DOI: 10.3390/biom3030351] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that activates a family of G protein coupled-receptors (GPCRs) implicated in mammalian development, angiogenesis, immunity and tissue regeneration. S1P functions as a trophic factor for many cell types, including embryonic stem cells (ESCs). Sphingosine phosphate lyase (SPL) is an intracellular enzyme that catalyzes the irreversible degradation of S1P. We found SPL to be highly expressed in murine ESCs (mESCs). To investigate the role of SPL in mESC biology, we silenced SPL in mESCs via stable transfection with a lentiviral SPL-specific short hairpin RNA (shRNA) construct. SPL-knockdown (SPL-KD) mESCs showed a 5-fold increase in cellular S1P levels, increased proliferation rates and high expression of cell surface pluripotency markers SSEA1 and OCT4 compared to vector control cells. Compared to control mESCs, SPL-KD cells showed robust activation of STAT3 and a 10-fold increase in S1P2 expression. Inhibition of S1P2 or STAT3 reversed the proliferation and pluripotency phenotypes of SPL-KD mESCs. Further, inhibition of S1P2 attenuated, in a dose-dependent fashion, the high levels of OCT4 and STAT3 activation observed in SPL-KD mESCs. Finally, we showed that SPL-KD cells are capable of generating embryoid bodies from which muscle stem cells, called satellite cells, can be isolated. These findings demonstrate an important role for SPL in ESC homeostasis and suggest that SPL inhibition could facilitate ex vivo ESC expansion for therapeutic purposes.
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Chipuk JE, McStay GP, Bharti A, Kuwana T, Clarke CJ, Siskind LJ, Obeid LM, Green DR. Sphingolipid metabolism cooperates with BAK and BAX to promote the mitochondrial pathway of apoptosis. Cell 2012; 148:988-1000. [PMID: 22385963 DOI: 10.1016/j.cell.2012.01.038] [Citation(s) in RCA: 336] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 08/10/2011] [Accepted: 01/20/2012] [Indexed: 01/28/2023]
Abstract
Mitochondria are functionally and physically associated with heterotypic membranes, yet little is known about how these interactions impact mitochondrial outer-membrane permeabilization (MOMP) and apoptosis. We observed that dissociation of heterotypic membranes from mitochondria inhibited BAK/BAX-dependent cytochrome c (cyto c) release. Biochemical purification of neutral sphingomyelinases that correlated with MOMP sensitization suggested that sphingolipid metabolism coordinates BAK/BAX activation. Using purified lipids and enzymes, sensitivity to MOMP was achieved by in vitro reconstitution of the sphingolipid metabolic pathway. Sphingolipid metabolism inhibitors blocked MOMP from heavy membrane preparations but failed to influence MOMP in the presence of sphingolipid-reconstituted, purified mitochondria. Furthermore, the sphingolipid products, sphingosine-1-PO(4) and hexadecenal, cooperated specifically with BAK and BAX, respectively. Sphingolipid metabolism was also required for cellular responses to apoptosis. Our studies suggest that BAK/BAX activation and apoptosis are coordinated through BH3-only proteins and a specific lipid milieu that is maintained by heterotypic membrane-mitochondrial interactions.
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Affiliation(s)
- Jerry E Chipuk
- Mount Sinai School of Medicine, Department of Oncological Sciences, New York, NY 10029, USA.
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Cantrell Stanford J, Morris AJ, Sunkara M, Popa GJ, Larson KL, Özcan S. Sphingosine 1-phosphate (S1P) regulates glucose-stimulated insulin secretion in pancreatic beta cells. J Biol Chem 2012; 287:13457-64. [PMID: 22389505 DOI: 10.1074/jbc.m111.268185] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent studies suggest that sphingolipid metabolism is altered during type 2 diabetes. Increased levels of the sphingolipid ceramide are associated with insulin resistance. However, a role for sphingolipids in pancreatic beta cell function, or insulin production, and release remains to be established. Our studies in MIN6 cells and mouse pancreatic islets demonstrate that glucose stimulates an intracellular rise in the sphingolipid, sphingosine 1-phosphate (S1P), whereas the levels of ceramide and sphingomyelin remain unchanged. The increase in S1P levels by glucose is due to activation of sphingosine kinase 2 (SphK2). Interestingly, rises in S1P correlate with increased glucose-stimulated insulin secretion (GSIS). Decreasing S1P levels by treatment of MIN6 cells or primary islets with the sphingosine kinase inhibitor reduces GSIS. Moreover, knockdown of SphK2 alone results in decreased GSIS, whereas knockdown of the S1P phosphatase, Sgpp1, leads to a rise in GSIS. Treatment of mice with the sphingosine kinase inhibitor impairs glucose disposal due to decreased plasma insulin levels. Altogether, our data suggest that glucose activates SphK2 in pancreatic beta cells leading to a rise in S1P levels, which is important for GSIS.
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Affiliation(s)
- Jamie Cantrell Stanford
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
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Meng H, Yuan Y, Lee VM. Loss of sphingosine kinase 1/S1P signaling impairs cell growth and survival of neurons and progenitor cells in the developing sensory ganglia. PLoS One 2011; 6:e27150. [PMID: 22096531 PMCID: PMC3212543 DOI: 10.1371/journal.pone.0027150] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 10/11/2011] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Lysophospholipids such as lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are important signaling molecules that can regulate a wide range of cellular responses. We discovered that Sphingosine kinase 1 (Sphk1), a key enzyme that converts sphingosine to S1P, is expressed in neurons and progenitor cells in nascent trigeminal and dorsal root ganglia during mouse embryogenesis. METHODS AND FINDINGS Sphk1 null mouse embryos do not display overt deficits owing to compensation by Sphk2. Thus, we analyzed embryos that are deficient in both Sphk1 and Sphk2 (which essentially eliminates S1P function) in order to investigate the role(s) of Sphk1 during sensory ganglia formation. While animals lacking 1-3 alleles of Sphk1 and Sphk2 had no obvious phenotype, embryos without both genes displayed clear developmental defects. The complete absence of Sphk1 and Sphk2 resulted in trigeminal and dorsal root ganglia with fewer neurons and progenitor cells. The profound loss in cell number could be attributed to a decrease in cell proliferation as well as an increase in apoptosis. Furthermore, Sphk1/2 double mutants displayed an overall reduction in other sphingolipids as well as an imbalance of S1P/sphingosine and S1P/ceramide ratio, thereby favoring cell death and reducing cell growth. CONCLUSIONS Together, these results provide strong in vivo evidence that sphingosine kinase/S1P signaling plays an important role in regulating early events during development of sensory ganglia.
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Affiliation(s)
- Hui Meng
- Division of Developmental Biology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yuan Yuan
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Vivian M. Lee
- Division of Developmental Biology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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Yonamine I, Bamba T, Nirala NK, Jesmin N, Kosakowska-Cholody T, Nagashima K, Fukusaki E, Acharya JK, Acharya U. Sphingosine kinases and their metabolites modulate endolysosomal trafficking in photoreceptors. ACTA ACUST UNITED AC 2011; 192:557-67. [PMID: 21321100 PMCID: PMC3044112 DOI: 10.1083/jcb.201004098] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Alterations in sphingosine kinase activity change the degradation rates of Rhodopsin and the transient receptor potential (TRP) channel by lysosomes and can result in retinal degeneration. Internalized membrane proteins are either transported to late endosomes and lysosomes for degradation or recycled to the plasma membrane. Although proteins involved in trafficking and sorting have been well studied, far less is known about the lipid molecules that regulate the intracellular trafficking of membrane proteins. We studied the function of sphingosine kinases and their metabolites in endosomal trafficking using Drosophila melanogaster photoreceptors as a model system. Gain- and loss-of-function analyses show that sphingosine kinases affect trafficking of the G protein–coupled receptor Rhodopsin and the light-sensitive transient receptor potential (TRP) channel by modulating the levels of dihydrosphingosine 1 phosphate (DHS1P) and sphingosine 1 phosphate (S1P). An increase in DHS1P levels relative to S1P leads to the enhanced lysosomal degradation of Rhodopsin and TRP and retinal degeneration in wild-type photoreceptors. Our results suggest that sphingosine kinases and their metabolites modulate photoreceptor homeostasis by influencing endolysosomal trafficking of Rhodopsin and TRP.
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Affiliation(s)
- Ikuko Yonamine
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Lankalapalli RS, Ouro A, Arana L, Gómez-Muñoz A, Bittman R. Caged ceramide 1-phosphate analogues: synthesis and properties. J Org Chem 2010; 74:8844-7. [PMID: 19908915 DOI: 10.1021/jo902076w] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sphingolipid phosphate analogues bearing 7-(diethylamino)coumarin (DECM) and 4-bromo-5-hydroxy-2-nitrobenzhydryl (BHNB) groups in a photolabile ester bond were synthesized. The ability of the "caged" ceramide 1-phosphate analogues to release the bioactive parent molecule upon irradiation at 400-500 nm was demonstrated by stimulation of macrophage cell proliferation.
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Affiliation(s)
- Ravi S Lankalapalli
- Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, New York 11367-1597, USA
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Serra M, Saba JD. Sphingosine 1-phosphate lyase, a key regulator of sphingosine 1-phosphate signaling and function. ACTA ACUST UNITED AC 2009; 50:349-62. [PMID: 19914275 DOI: 10.1016/j.advenzreg.2009.10.024] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Montserrat Serra
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609-1673, USA
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Kolter T, Sandhoff K. Lysosomal degradation of membrane lipids. FEBS Lett 2009; 584:1700-12. [PMID: 19836391 DOI: 10.1016/j.febslet.2009.10.021] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 10/09/2009] [Indexed: 01/05/2023]
Abstract
The constitutive degradation of membrane components takes place in the acidic compartments of a cell, the endosomes and lysosomes. Sites of lipid degradation are intralysosomal membranes that are formed in endosomes, where the lipid composition is adjusted for degradation. Cholesterol is sorted out of the inner membranes, their content in bis(monoacylglycero)phosphate increases, and, most likely, sphingomyelin is degraded to ceramide. Together with endosomal and lysosomal lipid-binding proteins, the Niemann-Pick disease, type C2-protein, the GM2-activator, and the saposins sap-A, -B, -C, and -D, a suitable membrane lipid composition is required for degradation of complex lipids by hydrolytic enzymes.
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Affiliation(s)
- Thomas Kolter
- LiMES - Life and Medical Sciences Institute, Membrane Biology and Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, University of Bonn, Bonn, Germany
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