scholarly journals Sphingolipid Profiling Reveals Different Extent of Ceramide Accumulation in Bovine Retroperitoneal and Subcutaneous Adipose Tissues

Metabolites ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 473
Author(s):  
Yue Hei Leung ◽  
Sonja Christiane Bäßler ◽  
Christian Koch ◽  
Theresa Scheu ◽  
Ulrich Meyer ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
De Novo ◽  
Specific Activity ◽  
Multiple Reaction Monitoring ◽  
De Novo Synthesis ◽  
Bioactive Lipids ◽  
Tissue Specific ◽  
Sphingosine 1 Phosphate ◽  
Ceramide Accumulation ◽  
Subcutaneous Adipose

Sphingolipids are bioactive lipids that can modulate insulin sensitivity, cellular differentiation, and apoptosis in a tissue-specific manner. However, their comparative profiles in bovine retroperitoneal (RPAT) and subcutaneous adipose tissue (SCAT) are currently unknown. We aimed to characterize the sphingolipid profiles using a targeted lipidomics approach and to assess whether potentially related sphingolipid pathways are different between SCAT and RPAT. Holstein bulls (n = 6) were slaughtered, and SCAT and RPAT samples were collected for sphingolipid profiling. A total of 70 sphingolipid species were detected and quantified by UPLC-MS/MS in multiple reaction monitoring (MRM) mode, including ceramide (Cer), dihydroceramide (DHCer), sphingomyelin (SM), dihydrosphingomyelin (DHSM), ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), galactosylceramide (GalCer), glucosylceramide (GluCer), lactosylceramide (LacCer), sphinganine (DHSph), and sphingosine (Sph). Our results showed that sphingolipids of the de novo synthesis pathway, such as DHSph, DHCer, and Cer, were more concentrated in RPAT than in SCAT. Sphingolipids of the salvage pathway and the sphingomyelinase pathway, such as Sph, S1P, C1P, glycosphingolipid, and SM, were more concentrated in SCAT. Our results indicate that RPAT had a greater extent of ceramide accumulation, thereby increasing the concentration of further sphingolipid intermediates in the de novo synthesis pathway. This distinctive sphingolipid distribution pattern in RPAT and SCAT can potentially explain the tissue-specific activity in insulin sensitivity, proinflammation, and oxidative stress in RPAT and SCAT.

scholarly journals Sphingolipid Profiling Reveals Different Extent of Ceramide Accumulation in Bovine Retroperitoneal and Subcutaneous Adipose Tissues

2020 ◽  
Author(s):  
Yue Hei Leung ◽  
Sonja Baessler ◽  
Christian Koch ◽  
Theresa Scheu ◽  
Ulrich Meyer ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
De Novo ◽  
Specific Activity ◽  
Lipolytic Activity ◽  
Bioactive Lipids ◽  
Tissue Specific ◽  
Sphingosine 1 Phosphate ◽  
Ceramide Accumulation ◽  
Subcutaneous Adipose

Abstract Background: Sphingolipids are bioactive lipids that can modulate insulin sensitivity, cellular differentiation, and apoptosis in a tissue-specific manner. Previous studies in dairy cattle reported that the retroperitoneal adipose tissue (RPAT) was more active than the subcutaneous adipose tissue (SCAT) in terms of insulin sensitivity, lipolytic activity, and pro-inflammatory signaling. Sphingolipids were discussed to be involved in inflammation, however, their comparative profiles in bovine RPAT and SCAT are currently unknown. We aimed to characterize the sphingolipid profiles using a targeted lipidomics approach and to assess whether potentially related sphingolipid pathways are different between SCAT and RPAT. Holstein bulls (n = 6) were slaughtered, and SCAT and RPAT samples were collected for sphingolipid profiling. A total of 70 sphingolipid species were detected, including 24 species of ceramide (Cer) and dihydroceramide (DHCer), 18 species of sphingomyelin (SM) and dihydrosphingomyelin (DHSM), 11 species of ceramide-1-phosphate (C1P) and sphingosine-1-phosphate (S1P), 9 species of galactosylceramide (GalCer), glucosylceramide (GluCer), lactosylceramide (LacCer), and 8 species of sphinganine (DHSph) and sphingosine (Sph). The concentration of each sphingolipid was quantified by UPLC-MRM/MS. Results: Our results showed that sphingolipids of the de novo synthesis pathway such as DHSph, DHCer, and Cer, were more concentrated in RPAT than in SCAT. Sphingolipids of the salvage pathway and the sphingomyelinase pathway such as Sph, S1P, C1P, glycosphingolipid, and SM were more concentrated in SCAT. Our results indicate that RPAT had a greater extent of ceramide accumulation, and thereby increased the concentration of further sphingolipid intermediates in the de novo synthesis pathway.Conclusion: This distinctive sphingolipid distribution pattern in RPAT and SCAT can potentially explain the tissue-specific activity in insulin sensitivity, pro-inflammation, and oxidative stress in RPAT and SCAT.

Rates of de novo Synthesis of Malate Synthase and Albumins during the Very Early Phase of Germination

1979 ◽  
Vol 34 (12) ◽  
pp. 1237-1242 ◽  
Author(s):  
Wolfram Köller ◽  
Helmut Kindl
Keyword(s):  
Early Phase ◽  
De Novo ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
Malate Synthase ◽  
Polyacrylamide Gel ◽  
De Novo Synthesis ◽  
Albumin Fraction ◽  
Average Value ◽  
Large Pool

Abstract Malate synthase is synthesized de novo in the very early phase of germination. Its molecular and immunological properties do not differ from those of malate synthase from fully developed cotyledons. Radioactive leucine was administered to dry seeds of cucumber, and its incorporation into proteins of cotyledons was examined after 2 days of germination. The specific radioactivity of malate synthase, purified by immunoprecipitation and electrophoresis on polyacrylamide gel, was only 1/20 the average value of the total albumin fraction. The minimal incorporation documented by the comparatively low specific activity of isolated malate synthase is discussed in relation to the large pool of malate synthase already present in dry seeds.

scholarly journals Sphingolipids in Lung Pathology in the Coronavirus Disease Era: A Review of Sphingolipid Involvement in the Pathogenesis of Lung Damage

2021 ◽  
Vol 12 ◽  
Author(s):  
Saad A. Khan ◽  
Kayla F. Goliwas ◽  
Jessy S. Deshane
Keyword(s):  
De Novo ◽  
Therapeutic Option ◽  
Treatment Options ◽  
Lung Damage ◽  
Lung Pathology ◽  
Cytokine Storm ◽  
Bioactive Lipids ◽  
Chronic Lung Diseases ◽  
Sphingosine 1 Phosphate ◽  
Novel Coronavirus

Sphingolipids are bioactive lipids involved in the regulation of cell survival, proliferation, and the inflammatory response. The SphK/S1P/S1PR pathway (S1P pathway) is a driver of many anti-apoptotic and proliferative processes. Pro-survival sphingolipid sphingosine-1-phosphate (S1P) initiates its signaling cascade by interacting with various sphingosine-1-phosphate receptors (S1PR) through which it is able to exert its pro-survival or inflammatory effects. Whereas sphingolipids, including ceramides and sphingosines are pro-apoptotic. The pro-apoptotic lipid, ceramide, can be produced de novo by ceramide synthases and converted to sphingosine by way of ceramidases. The balance of these antagonistic lipids and how this balance manifests is the essence of the sphingolipid rheostat. Recent studies on SARS-CoV-2 have implicated the S1P pathway in the pathogenesis of novel coronavirus disease COVID-19-related lung damage. Accumulating evidence indicates that an aberrant inflammatory process, known as “cytokine storm” causes lung injury in COVID-19, and studies have shown that the S1P pathway is involved in signaling this hyperinflammatory response. Beyond the influence of this pathway on cytokine storm, over the last decade the S1P pathway has been investigated for its role in a wide array of lung pathologies, including pulmonary fibrosis, pulmonary arterial hypertension (PAH), and lung cancer. Various studies have used S1P pathway modulators in models of lung disease; many of these efforts have yielded results that point to the potential efficacy of targeting this pathway for future treatment options. Additionally, they have emphasized S1P pathway’s significant role in inflammation, fibrosis, and a number of other endothelial and epithelial changes that contribute to lung damage. This review summarizes the S1P pathway’s involvement in COVID-19 and chronic lung diseases and discusses the potential for targeting S1P pathway as a therapeutic option for these diseases.

Enhanced RNA and protein synthesis in adipose tissue of rats adapted to periodic hyperphagia

1968 ◽  
Vol 46 (6) ◽  
pp. 903-906 ◽  
Author(s):  
L. Kazdová ◽  
T. Braun ◽  
P. Fábry ◽  
R. Poledne
Keyword(s):  
Protein Synthesis ◽  
Adipose Tissue ◽  
Rna Synthesis ◽  
De Novo ◽  
Specific Activity ◽  
De Novo Synthesis ◽  
Experimental Conditions ◽  
Rna And Protein Synthesis ◽  
Meal Feeding ◽  
The Difference

RNA synthesis measured by the incorporation of orotic acid-6-14C into RNA was investigated in isolated adipose tissue of control rats and of rats adapted to periodic hyperphagia, evoked by meal-feeding (a single 2-h meal per day). Both groups were fasted for 22 h and subsequently fed a measured test meal for another 2 h. It was revealed that 2 and 4 h after feeding there was no significant change in comparison with values during fasting, whereas in tissue of meal-fed rats the specific activity of RNA gradually increased by 22% and 41% respectively. The difference between controls and meal-fed rats was even much more marked if the specific activity of RNA in fat cells, isolated after incubation of the tissue, was measured. A significantly greater response of meal-fed rats was found when protein synthesis and lipogenesis in adipose tissue were assessed under the same experimental conditions. The possibility is discussed that the enhanced RNA and protein synthesis in adipose tissue of meal-fed rats is associated with de novo synthesis of enzymes involved in adaptive hyperlipogenesis.

scholarly journals The Crucial Role of C18-Cer in Fat-Induced Skeletal Muscle Insulin Resistance

2016 ◽  
Vol 40 (5) ◽  
pp. 1207-1220 ◽  
Author(s):  
Agnieszka U. Blachnio-Zabielska ◽  
Marta Chacinska ◽  
Mikkel H. Vendelbo ◽  
Piotr Zabielski
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
De Novo ◽  
Synthesis Rate ◽  
Standard Diet ◽  
Bioactive Lipids ◽  
Skeletal Muscle Insulin Resistance ◽  
Lipid Species

Background/Aims: Muscle bioactive lipids accumulation leads to several disorder states. The most common are insulin resistance (IR) and type 2 diabetes. There is an ongoing debate which of the lipid species plays the major role in induction of muscle IR. Our aim was to elucidate the role of particular lipid group in induction of muscle IR. Methods: The analyses were performed on muscle from the following groups of rats: 1. Control, fed standard diet, 2 HFD, fed high fat diet, 3. HFD/Myr, fed HFD and treated with myriocin (Myr), an inhibitor of ceramide de novo synthesis. We utilized [U13C] palmitate isotope tracer infusion and mass spectrometry to measure content and synthesis rate of muscle long-chain acyl-CoA (LCACoA), diacylglycerols (DAG) and ceramide (Cer). Results: HFD led to intramuscular accumulation of LCACoA, DAG and Cer and skeletal muscle IR. Myr-treatment caused decrease in Cer (most noticeable for stearoyl-Cer and oleoyl-Cer) and accumulation of DAG, possibly due to re-channeling of excess of intramuscular LCACoA towards DAG synthesis. An improvement in insulin sensitivity at both systemic and muscular level coincided with decrease in ceramide, despite elevated intramuscular DAG. Conclusion: The improved insulin sensitivity was associated with decreased muscle stearoyl- and oleoyl-ceramide content. The results indicate that accumulation of those ceramide species has the greatest impact on skeletal muscle insulin sensitivity in rats.

scholarly journals DRES-09. REGULATORY EFFECTS OF THE CILIARY GTPASE ARL13B ON PURINE METABOLISM IN GBM

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi73-vi73
Author(s):  
Miranda Saathoff ◽  
Jack Shireman ◽  
Eunus Ali ◽  
Cheol Park ◽  
Issam Ben-Sahra ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
De Novo ◽  
Specific Activity ◽  
Purine Metabolism ◽  
P Value ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Dna Double Strand Breaks ◽  
Purine Nucleotides ◽  
Regulatory Effects

Abstract Glioblastoma (GBM) is the most common form of adult primary brain cancer. Despite an aggressive treatment regimen – surgical resection, irradiation, and temozolomide (TMZ) chemotherapy – patients’ prognosis is still grim. TMZ acts by methylating purines, specifically at the O6 and N7 positions of guanine, to induce cytotoxic DNA double-strand breaks. We thus wanted to explore how purine metabolism may contribute to TMZ-resistance. In mammalian cells, purine nucleotides can be recycled by the salvage pathway or generated via de novo synthesis. The salvage pathway is energetically inexpensive relative to de novo thus, highly proliferative GBM cells preferentially utilize the salvage pathway. We have shown that salvage synthesis is reduced in response to TMZ (p-value=0.0021), hinting that the cells may utilize de novo to evade therapy induced alkylation of purines. Using immunoprecipitation-mass spectroscopy analysis, we found a novel interaction between the ciliary GTPase ARL13B and IMPDH2, the rate-limiting enzyme in de novo synthesis. We have shown that this interaction, occurring at the C-terminal domain of ARL13B, plays a significant role in the regulation of purine biosynthesis as abolishing it through ARL13B knockdown reduced flux through de novo (p-value< 0.0001) synthesis as measured by the specific activity of IMPDH2. Further, the lentiviral-mediated rescue of ARL13B brings IMPDH2 activity back to basal levels (p< 0.0001). Given its canonical function as a GTPase, we hypothesize that ARL13B acts as a novel regulator of de novo synthesis by sequestering GDP, allowing IMPDH2 to sense and respond to the cytosolic levels of guanine nucleotides. Without ARL13B the de novo pathway is halted, forcing the cells to rely on salvage to replenish nucleotide pools. Reliance on this pathway in the presence of TMZ causes cells to incorporate damaged nucleotides as a result of the drug’s alkylating action leading to the increased therapeutic efficacy of TMZ.

Structural and Metabolic Interrelationships Among Glycerophosphatides of Rat Liver In Vivo

1971 ◽  
Vol 49 (12) ◽  
pp. 1347-1356 ◽  
Author(s):  
B. J. Holub ◽  
A. Kuksis
Keyword(s):  
Rat Liver ◽  
De Novo ◽  
Specific Activity ◽  
Acyl Transfer ◽  
De Novo Synthesis ◽  
Individual Molecular Species ◽  
Relative Specific Activity ◽  
Proportional Contribution ◽  
Specific Activities

The specific activities of individual molecular species of rat liver diacylglycerylphosphorocholine (PC), diacylglycerylphosphoroethanolamine (PE), and diacylglycerophosphorylinositol (MPI) were determined and compared following intravenous injection of glycerol-14C. PC, PE, and MPI contained 41, 51, and 83%, respectively, tetraenoic species, and 40,17, and 9% combined mono-, di-, and trienoic species. The rest of the phosphatide mass of PC, PE, and MPI was contributed by 18, 32, and 8% penta- and hexaenoic species, respectively. The proportions of chemical classes of the glycerophosphatides differed by 1.1- to 18-fold while the fatty acid associations within the unsaturation classes common to these phosphatides varied 2.2- to 17-fold. After 5 min exposure to radioactive glycerol, the mono-, di-, and trienoic species of the PC, PE, and MPI possessed 13–18, 15–50, and 6–42 times, respectively, the specific activity of the tetraenes of the corresponding phosphatide classes. While the pentaenoic and hexaenoic species of PC and MPI had specific activities three to five times those of the respective tetraenes, the higher polyenes of PE were considerably more radioactive and approached the specific activity of the dienoic species of this phosphatide. With progressing time up to 60 min, the tetraenoic species of PC, PE, and MPI showed increases in relative specific activity of 50, 64, and 109%, respectively, in the three phosphatides. These results are consistent with an effective de novo synthesis of the oligoenoic species and a transacylation of the tetraenoic species of all liver glycerophosphatides tested. The proportional contribution of de novo synthesis in comparison to acyl transfer is apparently greater to the formation of PC and PE than to that of MPI.

The occurrence of a soluble glucose 6-phosphatase in cotyledon tissue of Phaseolus vulgaris during germination

1969 ◽  
Vol 47 (7) ◽  
pp. 685-689 ◽  
Author(s):  
J. E. Thompson
Keyword(s):  
Endoplasmic Reticulum ◽  
Phaseolus Vulgaris ◽  
De Novo ◽  
Specific Activity ◽  
Soluble Fraction ◽  
Soluble Form ◽  
Soluble Enzyme ◽  
De Novo Synthesis ◽  
Soluble Enzymes ◽  
Ph Profiles

Cotyledon tissue from seedlings of Phaseolus vulgaris at various stages of germination was homogenized and fractionated under isotonic conditions. Measurement of glucose 6-phosphatase (D-glucose 6-phosphate phosphohydrolase, EC 3.1.3.9) activity in the isolated fractions showed an increase in the level of soluble enzyme with advancing age of the cotyledons, such that by late senescence (10 days of age) approximately 90% of the recovered glucose 6-phosphatase was present in the soluble fraction, and its specific activity was about twofold greater than that of the homogenate. The pH profiles of the bound and soluble enzymes were found to be closely similar. The presence of a soluble glucose 6-phosphatase has been interpreted as indicating either de novo synthesis of the soluble form of the enzyme with advancing senescence, or solubilization of normally bound enzyme which may in turn reflect a partial breakdown in the structure of endoplasmic reticulum in senescent cells.

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 The Ormdl genes regulate the sphingolipid synthesis pathway to ensure proper myelination and neurologic function in mice

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Benjamin A Clarke ◽  
Saurav Majumder ◽  
Hongling Zhu ◽  
Y Terry Lee ◽  
Mari Kono ◽  
...  
Keyword(s):  
De Novo ◽  
Feedback Inhibition ◽  
Sphingolipid Metabolism ◽  
De Novo Synthesis ◽  
Bioactive Lipids ◽  
Mammalian Development ◽  
Metabolic Intermediates ◽  
Physiological Processes ◽  
Neurologic Function

Sphingolipids are membrane and bioactive lipids that are required for many aspects of normal mammalian development and physiology. However, the importance of the regulatory mechanisms that control sphingolipid levels in these processes is not well understood. The mammalian ORMDL proteins (ORMDL1, 2 and 3) mediate feedback inhibition of the de novo synthesis pathway of sphingolipids by inhibiting serine palmitoyl transferase in response to elevated ceramide levels. To understand the function of ORMDL proteins in vivo, we studied mouse knockouts (KOs) of the Ormdl genes. We found that Ormdl1 and Ormdl3 function redundantly to suppress the levels of bioactive sphingolipid metabolites during myelination of the sciatic nerve. Without proper ORMDL-mediated regulation of sphingolipid synthesis, severe dysmyelination results. Our data indicate that the Ormdls function to restrain sphingolipid metabolism in order to limit levels of dangerous metabolic intermediates that can interfere with essential physiological processes such as myelination.

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