Regulation of de novo sphingolipid biosynthesis and the toxic consequences of its disruption

2001 ◽  
Vol 29 (6) ◽  
pp. 831-835 ◽  
Author(s):  
S. C. Linn ◽  
H. S. Kim ◽  
E. M. Keane ◽  
L. M. Andras ◽  
E. Wang ◽  
...  
Keyword(s):  
De Novo ◽  
Uv Light ◽  
Wide Spectrum ◽  
Sphingolipid Metabolism ◽  
Intrinsic Activity ◽  
Type I ◽  
Serine Palmitoyltransferase ◽  
Post Translational Modification ◽  
Sphingolipid Biosynthesis ◽  
Complex Sphingolipids

Complex sphingolipids are ‘built’ on highly bio-active backbones (sphingoid bases and ceramides) that can cause cell death when the amounts are elevated by turnover of complex sphingolipids, disruption of normal sphingolipid metabolism, or over-induction of sphingolipid biosynthesis de novo. Under normal conditions, it appears that the bioactive intermediates of this pathway (3-keto-sphinganine, sphinganine and ceramides) are kept at relatively low levels. Both the intrinsic activity of serine palmitoyltransferase (SPT) and the availability of its substrates (especially palmitoyl-CoA) can have toxic consequences for cells by increasing the production of cytotoxic intermediates. Recent work has also revealed that diverse agonists and stresses (cytokines, UV light, glucocorticoids, heat shock and toxic compounds) modulate SPT activity by induction of SPTLC2 gene transcription and/or post-translational modification. Mutation of the SPTLC1 component of SPT has also been shown to cause hereditary sensory neuropathy type I, possibly via aberrant oversynthesis of sphingolipids. Another key step of the pathway is the acylation of sphinganine (and sphingosine in the recycling pathway) by ceramide synthase, and up-regulation of this enzyme (or its inhibition to cause accumulation of sphinganine) can also be toxic for cells. Since it appears that most, if not all, tissues synthesize sphingolipids de novo, it may not be surprising that disruption of this pathway has been implicated in a wide spectrum of disease.

scholarly journals Feeding Stimulates Sphingosine-1-Phosphate Mobilization in Mouse Hypothalamus

2019 ◽  
Vol 20 (16) ◽  
pp. 4008
Author(s):  
Valentina Vozella ◽  
Natalia Realini ◽  
Alessandra Misto ◽  
Daniele Piomelli
Keyword(s):  
De Novo ◽  
Sphingolipid Metabolism ◽  
Rt Pcr ◽  
Liquid Chromatography Tandem Mass ◽  
Sphingosine 1 Phosphate ◽  
Phosphate Mobilization ◽  
S1p Receptor ◽  
Free Feeding ◽  
G Protein Coupled ◽  
Sphingolipid Biosynthesis

Previous studies have shown that the sphingolipid-derived mediator sphingosine-1-phosphate (S1P) reduces food intake by activating G protein-coupled S1P receptor-1 (S1PR1) in the hypothalamus. Here, we examined whether feeding regulates hypothalamic mobilization of S1P and other sphingolipid-derived messengers. We prepared lipid extracts from the hypothalamus of C57Bl6/J male mice subjected to one of four conditions: free feeding, 12 h fasting, and 1 h or 6 h refeeding. Liquid chromatography/tandem mass spectrometry was used to quantify various sphingolipid species, including sphinganine (SA), sphingosine (SO), and their bioactive derivatives SA-1-phosphate (SA1P) and S1P. In parallel experiments, transcription of S1PR1 (encoded in mice by the S1pr1 gene) and of key genes of sphingolipid metabolism (Sptlc2, Lass1, Sphk1, Sphk2) was measured by RT-PCR. Feeding increased levels of S1P (in pmol-mg−1 of wet tissue) and SA1P. This response was accompanied by parallel changes in SA and dihydroceramide (d18:0/18:0), and was partially (SA1P) or completely (S1P) reversed by fasting. No such effects were observed with other sphingolipid species targeted by our analysis. Feeding also increased transcription of Sptlc2, Lass1, Sphk2, and S1pr1. Feeding stimulates mobilization of endogenous S1PR1 agonists S1P and SA1P in mouse hypothalamus, via a mechanism that involves transcriptional up-regulation of de novo sphingolipid biosynthesis. The results support a role for sphingolipid-mediated signaling in the central control of energy balance.

scholarly journals Crassaostrea gigas Oyster Shell Extract Inhibits Lipogenesis via Suppression of Serine Palmitoyltransferase

2015 ◽  
Vol 10 (2) ◽  
pp. 1934578X1501000
Author(s):  
Nguyen Khoi Song Tran ◽  
Jeong Eun Kwon ◽  
Se Chan Kang ◽  
Soon-Mi Shim ◽  
Tae-Sik Park
Keyword(s):  
De Novo ◽  
Preventive Measure ◽  
Ethanol Extract ◽  
Oyster Shell ◽  
Lipid Lowering ◽  
Metabolic Dysfunction ◽  
Serine Palmitoyltransferase ◽  
Lipogenic Gene Expression ◽  
Cholesterol Levels ◽  
Sphingolipid Biosynthesis

Oysters are widely consumed seafood, but their shells impose a serious environmental problem. To extend the utilization of oyster shell waste, we investigated the biological role of oyster shell extract. In this study, we verified that the ethanol extract of oyster shell (EOS) contains taurine and betaine, the major components of oyster body. EOS downregulated transcription of Sptlc1 and Sptlc2 mRNA, the subunits of serine palmitoyltransferase (SPT). Suppression of SPT subunits reduced sphinganine and sphingomyelin by inhibiting de novo sphingolipid biosynthesis. Inhibition of sphingomyelin biosynthesis resulted in downregulation of lipogenic gene expression such as ACC, FAS, SCD1, and DGAT2. Consistent with inhibition of lipogenesis, cellular triglyceride levels were diminished by EOS, but cholesterol levels were not altered. Taken together, these results suggest that EOS has a lipid-lowering effect and could be applied as either a therapeutic or preventive measure for metabolic dysfunction.

scholarly journals TORC1-regulated protein kinase Npr1 phosphorylates Orm to stimulate complex sphingolipid synthesis

2013 ◽  
Vol 24 (6) ◽  
pp. 870-881 ◽  
Author(s):  
Mitsugu Shimobayashi ◽  
Wolfgang Oppliger ◽  
Suzette Moes ◽  
Paul Jenö ◽  
Michael N. Hall
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Physiological Response ◽  
De Novo ◽  
Serine Palmitoyltransferase ◽  
De Novo Synthesis ◽  
Amino Acid Permease ◽  
Evolutionarily Conserved ◽  
General Amino Acid Permease ◽  
And Function ◽  
Complex Sphingolipids

The evolutionarily conserved Orm1 and Orm2 proteins mediate sphingolipid homeostasis. However, the homologous Orm proteins and the signaling pathways modulating their phosphorylation and function are incompletely characterized. Here we demonstrate that inhibition of nutrient-sensitive target of rapamycin complex 1 (TORC1) stimulates Orm phosphorylation and synthesis of complex sphingolipids in Saccharomyces cerevisiae. TORC1 inhibition activates the kinase Npr1 that directly phosphorylates and activates the Orm proteins. Npr1-phosphorylated Orm1 and Orm2 stimulate de novo synthesis of complex sphingolipids downstream of serine palmitoyltransferase. Complex sphingolipids in turn stimulate plasma membrane localization and activity of the nutrient scavenging general amino acid permease 1. Thus activation of Orm and complex sphingolipid synthesis upon TORC1 inhibition is a physiological response to starvation.

scholarly journals Rescue of cell growth by sphingosine with disruption of lipid microdomain formation in Saccharomyces cerevisiae deficient in sphingolipid biosynthesis

2006 ◽  
Vol 394 (1) ◽  
pp. 237-242 ◽  
Author(s):  
Motohiro Tani ◽  
Akio Kihara ◽  
Yasuyuki Igarashi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Serine Palmitoyltransferase ◽  
Kinase Gene ◽  
Yeast Saccharomyces Cerevisiae ◽  
Long Chain Base ◽  
Triton X ◽  
Lipid Microdomain ◽  
Sphingolipid Biosynthesis ◽  
Complex Sphingolipids

In the yeast Saccharomyces cerevisiae, sphingolipids are essential for cell growth. Inactivation of sphingolipid biosynthesis, such as by disrupting the serine palmitoyltransferase gene (LCB2), is lethal, but cells can be rescued by supplying an exogenous LCB (long-chain base) like PHS (phytosphingosine) or DHS (dihydrosphingosine). In the present study, supplying SPH (sphingosine), an unnatural LCB for yeast, similarly rescued the Δlcb2 cells, but only when SPH 1-phosphate production was inhibited by deleting the LCB kinase gene LCB4. Exogenously added SPH was adequately converted into phosphoinositol-containing complex sphingolipids. Interestingly, cells carrying SPH-based sphingolipids exhibited a defect in the association of Pma1p with Triton X-100-insoluble membrane fractions, and displayed sensitivities to both Ca2+ and hygromycin B. These results suggest that the SPH-based sphingolipids in these cells have properties that differ from those of the PHS- or DHS-based sphingolipids in regard to lipid microdomain formation, leading to abnormal sensitivities towards certain environmental stresses. The present paper is the first report showing that in sphingolipid-deficient S. cerevisiae, the requirement for LCB can be fulfilled by exogenous SPH, although this supplement results in failure of lipid microdomain formation.

scholarly journals Viral serine palmitoyltransferase induces metabolic switch in sphingolipid biosynthesis and is required for infection of a marine alga

2016 ◽  
Vol 113 (13) ◽  
pp. E1907-E1916 ◽  
Author(s):  
Carmit Ziv ◽  
Sergey Malitsky ◽  
Alaa Othman ◽  
Shifra Ben-Dor ◽  
Yu Wei ◽  
...  
Keyword(s):  
De Novo ◽  
Serine Palmitoyltransferase ◽  
Metabolic Switch ◽  
Marine Viruses ◽  
Key Enzyme ◽  
Infected Cells ◽  
Biochemical Analyses ◽  
Biological Entities ◽  
Sphingolipid Biosynthesis

Marine viruses are the most abundant biological entities in the oceans shaping community structure and nutrient cycling. The interaction between the bloom-forming algaEmiliania huxleyiand its specific large dsDNA virus (EhV) is a major factor determining the fate of carbon in the ocean, thus serving as a key host-pathogen model system. The EhV genome encodes for a set of genes involved in the de novo sphingolipid biosynthesis, not reported in any viral genome to date. We combined detailed lipidomic and biochemical analyses to characterize the functional role of this virus-encoded pathway during lytic viral infection. We identified a major metabolic shift, mediated by differential substrate specificity of virus-encoded serine palmitoyltransferase, a key enzyme of sphingolipid biosynthesis. Consequently, unique viral glycosphingolipids, composed of unusual hydroxylated C17 sphingoid bases (t17:0) were highly enriched in the infected cells, and their synthesis was found to be essential for viral assembly. These findings uncover the biochemical bases of the virus-induced metabolic rewiring of the host sphingolipid biosynthesis during the chemical “arms race” in the ocean.

scholarly journals Probing de novo sphingolipid metabolism in mammalian cells utilizing mass spectrometry

2018 ◽  
Vol 59 (6) ◽  
pp. 1046-1057 ◽  
Author(s):  
Justin M. Snider ◽  
Ashley J. Snider ◽  
Lina M. Obeid ◽  
Chiara Luberto ◽  
Yusuf A. Hannun
Keyword(s):  
Mammalian Cells ◽  
Metabolic Flux ◽  
De Novo ◽  
Bioactive Molecules ◽  
Sphingolipid Metabolism ◽  
Complete Analysis ◽  
Serine Palmitoyltransferase ◽  
One Step ◽  
Practical Tool

Sphingolipids constitute a dynamic metabolic network that interconnects several bioactive molecules, including ceramide (Cer), sphingosine (Sph), Sph 1-phosphate, and Cer 1-phosphate. The interconversion of these metabolites is controlled by a cohort of at least 40 enzymes, many of which respond to endogenous or exogenous stimuli. Typical probing of the sphingolipid pathway relies on sphingolipid mass levels or determination of the activity of individual enzymes. Either approach is unable to provide a complete analysis of flux through sphingolipid metabolism, which, given the interconnectivity of the sphingolipid pathway, is critical information to identify nodes of regulation. Here, we present a one-step in situ assay that comprehensively probes the flux through de novo sphingolipid synthesis, post serine palmitoyltransferase, by monitoring the incorporation and metabolism of the 17 carbon dihydrosphingosine precursor with LC/MS. Pulse labeling and analysis of precursor metabolism identified sequential well-defined phases of sphingolipid synthesis, corresponding to the activity of different enzymes in the pathway, further confirmed by the use of specific inhibitors and modulators of sphingolipid metabolism. This work establishes precursor pulse labeling as a practical tool for comprehensively studying metabolic flux through de novo sphingolipid synthesis and complex sphingolipid generation.

scholarly journals Sphingosine-1-phosphate phosphohydrolase in regulation of sphingolipid metabolism and apoptosis

2002 ◽  
Vol 158 (6) ◽  
pp. 1039-1049 ◽  
Author(s):  
Hervé Le Stunff ◽  
Ismael Galve-Roperh ◽  
Courtney Peterson ◽  
Sheldon Milstien ◽  
Sarah Spiegel
Keyword(s):  
Cell Fate ◽  
De Novo ◽  
Fumonisin B1 ◽  
Sphingolipid Metabolism ◽  
Ceramide Synthase ◽  
Serine Palmitoyltransferase ◽  
Intracellular Membranes ◽  
Sphingosine 1 Phosphate ◽  
Ceramide Accumulation ◽  
Membrane Treatment

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite that regulates diverse biological processes by binding to a family of G protein–coupled receptors or as an intracellular second messenger. Mammalian S1P phosphatase (SPP-1), which degrades S1P to terminate its actions, was recently cloned based on homology to a lipid phosphohydrolase that regulates the levels of phosphorylated sphingoid bases in yeast. Confocal microscopy surprisingly revealed that epitope-tagged SPP-1 is intracellular and colocalized with the ER marker calnexin. Moreover, SPP-1 activity and protein appeared to be mainly enriched in the intracellular membranes with lower expression in the plasma membrane. Treatment of SPP-1 transfectants with S1P markedly increased ceramide levels, predominantly in the intracellular membranes, diminished survival, and enhanced apoptosis. Remarkably, dihydro-S1P, although a good substrate for SPP-1 in situ, did not cause significant ceramide accumulation or increase apoptosis. Ceramide accumulation induced by S1P was completely blocked by fumonisin B1, an inhibitor of ceramide synthase, but only partially reduced by myriocin, an inhibitor of serine palmitoyltransferase, the first committed step in de novo synthesis of ceramide. Furthermore, S1P, but not dihydro-S1P, stimulated incorporation of [3H]palmitate, a substrate for both serine palmitoyltransferase and ceramide synthase, into C16-ceramide. Collectively, our results suggest that SPP-1 functions in an unprecedented manner to regulate sphingolipid biosynthesis and is poised to influence cell fate.

scholarly journals Uptake of exogenous serine is important to maintain sphingolipid homeostasis in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Bianca M. Esch ◽  
Sergej Limar ◽  
André Bogdanowski ◽  
Christos Gournas ◽  
Tushar More ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Membrane Lipids ◽  
Yeast Cells ◽  
Sphingolipid Metabolism ◽  
Flux Analysis ◽  
Amino Acid Permease ◽  
Membrane Contact Sites ◽  
Starting Point ◽  
Sphingolipid Biosynthesis

AbstractSphingolipids are abundant and essential molecules in eukaryotes that have crucial functions as signaling molecules and as membrane components. Sphingolipid biosynthesis starts in the endoplasmic reticulum with the condensation of serine and palmitoyl-CoA. Sphingolipid biosynthesis is highly regulated to maintain sphingolipid homeostasis. Even though, serine is an essential component of the sphingolipid biosynthesis pathway, its role in maintaining sphingolipid homeostasis has not been precisely studied. Here we show that serine uptake is an important factor for the regulation of sphingolipid biosynthesis in Saccharomyces cerevisiae. Using genetic experiments, we find the broad-specificity amino acid permease Gnp1 to be important for serine uptake. We confirm these results with serine uptake assays in gnp1Δ cells. We further show that uptake of exogenous serine by Gnp1 is important to maintain cellular serine levels and observe a specific connection between serine uptake and the first step of sphingolipid biosynthesis. Using mass spectrometry-based flux analysis, we further observed imported serine as the main source for de novo sphingolipid biosynthesis. Our results demonstrate that yeast cells preferentially use the uptake of exogenous serine to regulate sphingolipid biosynthesis. Our study can also be a starting point to analyze the role of serine uptake in mammalian sphingolipid metabolism.Author SummarySphingolipids (SPs) are membrane lipids globally required for eukaryotic life. In contrast to other lipid classes, SPs cannot be stored in the cell and therefore their levels have to be tightly regulated. Failure to maintain sphingolipid homeostasis can result in pathologies including neurodegeneration, childhood asthma and cancer. However, we are only starting to understand how SP biosynthesis is adjusted according to need. In this study, we use genetic and biochemical methods to show that the uptake of exogenous serine is necessary to maintain SP homeostasis in Saccharomyces cerevisiae. Serine is one of the precursors of long chain bases in cells, the first intermediate of SP metabolism. Our results suggest that the uptake of serine is directly coupled to SP biosynthesis at ER-plasma membrane contact sites. Overall, our study identifies serine uptake as a novel regulatory factor of SP homeostasis. While we use yeast as a discovery tool, these results also provide valuable insights into mammalian SP biology especially under pathological conditions.

scholarly journals A Dansyl-Modified Sphingosine Kinase Inhibitor Dpf-543 Enhanced de Novo Ceramide Generation

2021 ◽  
Author(s):  
Maftuna Shamshiddinova ◽  
Shokhid Gulyamov ◽  
Hee Jung Kim ◽  
Seo Hyeon Jung ◽  
Dong Jae Baek ◽  
...  
Keyword(s):  
Cancer Metastasis ◽  
Kinase Inhibitor ◽  
De Novo ◽  
Sphingosine Kinase ◽  
Acid Sphingomyelinase ◽  
Sphingolipid Metabolism ◽  
Ceramide Synthase ◽  
Serine Palmitoyltransferase ◽  
Comparative Efficiency ◽  
Sphingosine 1 Phosphate

Sphingosine-1-phosphate (S1P) synthesized by sphingosine kinase (SPHK) is a signaling molecule, involved in cell proliferation, growth, differentiation, and survival. Indeed, a sharp increase of S1P was linked to the pathological outcome with inflammation, cancer metastasis or angiogenesis etc. In this regard, the SPHK/S1P axis regulation has been a specific issue in anticancer strategy to turn accumulated sphingosine (SPN) into cytotoxic ceramides (Cers). For these purposes, there have been numerous chemicals synthesized for SPHK inhibition. In this study, we investigated the comparative efficiency of dansylated PF-543 (DPF-543) on the Cers synthesis along with PF-543. DPF-543 deserved attention in strong cytotoxicity, due to the cytotoxic Cers accumulation by ceramide synthase (CerSs). DPF-543 exhibited dual actions on Cers synthesis by enhance the serine palmitoyltransferase (SPT) activity, and by inhibiting SPHKs which eventually induced an unusual environment of the high amount of 3-ketosphinganine and sphinganine (SPA). SPA in turn was consumed to synthesize Cers via de novo pathway. Interestingly, PF-543 increased only the SPN level, but not for SPA. In addition, DPF-543 mildly activates acid sphingomyelinase (aSMase) that contributes a partial increase on Cers. Collectively, a dansyl-modified DPF-543 relatively en-hanced Cers accumulation via de novo pathway which was not observed in PF-543. Our results demonstrated that the structural modification on SPHK inhibitors is still an attractive anticancer strategy by regulating sphingolipid metabolism.

scholarly journals A Dansyl-Modified Sphingosine Kinase Inhibitor DPF-543 Enhanced De Novo Ceramide Generation

2021 ◽  
Vol 22 (17) ◽  
pp. 9190
Author(s):  
Maftuna Shamshiddinova ◽  
Shokhid Gulyamov ◽  
Hee-Jung Kim ◽  
Seo-Hyeon Jung ◽  
Dong-Jae Baek ◽  
...  
Keyword(s):  
Cancer Metastasis ◽  
Kinase Inhibitor ◽  
De Novo ◽  
Sphingosine Kinase ◽  
Acid Sphingomyelinase ◽  
Sphingolipid Metabolism ◽  
Ceramide Synthase ◽  
Serine Palmitoyltransferase ◽  
Comparative Efficiency ◽  
Sphingosine 1 Phosphate

Sphingosine-1-phosphate (S1P) synthesized by sphingosine kinase (SPHK) is a signaling molecule, involved in cell proliferation, growth, differentiation, and survival. Indeed, a sharp increase of S1P is linked to a pathological outcome with inflammation, cancer metastasis, or angiogenesis, etc. In this regard, SPHK/S1P axis regulation has been a specific issue in the anticancer strategy to turn accumulated sphingosine (SPN) into cytotoxic ceramides (Cers). For these purposes, there have been numerous chemicals synthesized for SPHK inhibition. In this study, we investigated the comparative efficiency of dansylated PF-543 (DPF-543) on the Cers synthesis along with PF-543. DPF-543 deserved attention in strong cytotoxicity, due to the cytotoxic Cers accumulation by ceramide synthase (CerSs). DPF-543 exhibited dual actions on Cers synthesis by enhancing serine palmitoyltransferase (SPT) activity, and by inhibiting SPHKs, which eventually induced an unusual environment with a high amount of 3-ketosphinganine and sphinganine (SPA). SPA in turn was consumed to synthesize Cers via de novo pathway. Interestingly, PF-543 increased only the SPN level, but not for SPA. In addition, DPF-543 mildly activates acid sphingomyelinase (aSMase), which contributes a partial increase in Cers. Collectively, a dansyl-modified DPF-543 relatively enhanced Cers accumulation via de novo pathway which was not observed in PF-543. Our results demonstrated that the structural modification on SPHK inhibitors is still an attractive anticancer strategy by regulating sphingolipid metabolism.

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