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At least 775 records · Page 43Linked to original sources
PubMed2004

Perturbation of sphingolipid metabolism and ceramide production in HIV-dementia.

Infection by the human immunodeficiency virus type 1 (HIV-1) often results in neurological dysfunction including HIV dementia (HIVD). Alterations in cytokine and redox balance are thought to play important roles in the pathogenesis of HIVD, but the specific mechanisms underlying neuronal dysfunction and death are unknown. Activation of cytokine receptors and oxidative stress can induce the production of ceramide from membrane sphingomyelin, and recent findings suggest that ceramide is an important mediator of a form of programmed cell death called apoptosis. We now report that levels of ceramide, sphingomyelin, and hydroxynonenal (HNE) are significantly increased in brain tissues and cerebrospinal fluid of HIVD patients. Exposure of cultured neurons to the neurotoxic HIV proteins gp120 and Tat resulted in increased cellular levels of sphingomyelin, ceramide, and HNE. The ceramide precursor palmitoyl-CoA sensitized neurons to Tat and gp120 toxicity, whereas an inhibitor of ceramide production reduced Tat and gp120-induced increases of ceramide and HNE and protected the neurons from Tat and gp120-induced death. These results suggest that HIV-1 infection may promote a lipid imbalance in neural cells, resulting in an overproduction of ceramide and consequent cellular dysfunction and death.

AIDS Dementia Complex↗
PubMed2006

Analysis of sphingolipids in potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) by reversed phase high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS).

Ceramides and glucocerebrosides of potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) were analyzed using RP-HPLC-ESI-MS/MS. Ceramides and glucocerebrosides containing the three different long-chain bases 4,8-sphingadienine (d18:2(delta4,delta8)), 4-hydroxy-8-sphingenine (t18:1(delta8)), and 8-sphingenine (d18:1(delta8)) acylated to saturated and unsaturated hydroxy- and nonhydroxy fatty acids with 16-26 carbon atoms were detected. For ceramides and glucocerebrosides 4,8-sphingadienine (d18:2(delta4,delta8)) was found as the major long-chain base, with lesser amounts of 4-hydroxy-8-sphingenine (t18:1(delta8)) and 8-sphingenine (d18:1(delta8)). 2-(Alpha-)hydroxypalmitic acid (C16:0h) was the major fatty acid, which was found to be acylated to the long-chain bases. For quantification of these compounds, an RP-HPLC-ESI-MS/MS method with an "echo-peak"-technique simulating internal standard injection was developed. The analyzed samples of potatoes and sweet potatoes showed amounts of approximately 0.1-8 microg/kg single ceramides and amounts up to 500 microg/kg glucocerebrosides, with C16:0h-glucosyl-4,8-sphingadienine as the major component.

Ceramides↗
PubMed1995

Evidence for indirect utilization of glycine for production of N-bases of glycerophospholipids and sphingolipids in mouse neuroblastoma cells by using 15N-labeled glycine.

After mouse neuroblastoma cells were cultured with [15N]glycine in Dulbecco's modified Eagle's medium for total four days, they gave significant amounts of 15N-atom% excess in phosphatidylserine, phosphatidylethanolamine, ethanolamine plasmalogen, phosphatidylcholine, sphingomyelin and ceramide. These results were compared with those of [15N]choline, [15N]ethanolamine and [15N]DL-serine used in place of [15N]glycine for the experiments. It was suggested that [15N]glycine is taken into the cells and metabolically converted to [15N]L-serine, which is well known to be used for the production of polar head groups of glycerophospholipids and sphingosine.

Animals↗
PubMed2001

Structure elucidation of sphingolipids from the mycopathogen Sporothrix schenckii: identification of novel glycosylinositol phosphorylceramides with core manalpha1-->6Ins linkage.

Acidic glycosphingolipid components were extracted from the mycelium form of the thermally dimorphic mycopathogen Sporothrix schenckii. Two fractions from the mycelium form (Ss-M1 and Ss-M2), having the highest Rf values on HPTLC analysis, were isolated and their structures elucidated by 1- and 2-D 13C- and 1H-nuclear magnetic resonance spectroscopy, and electrospray ionization mass spectrometry with lithium adduction of molecular ions. The structures of Ss-M1 and Ss-M2 were determined to be Manalpha1-->Ins1-P-1Cer and Manalpha1--> 3Manalpha1-->Ins1-P-1Cer, respectively (where Ins = myo-inositol, P = phosphodiester). The Manalpha1-->6Ins motif is found normally in diacylglycerol-based glycophosphatidylinositols of Mycobacteria, but this is the first unambiguous identification of the same linkage making up the core structure of fungal glycosylinositol phosphorylceramides (GIPCs). These results are discussed in relation to the structures of GIPCs of other mycopathogens, including Histoplasma capsulatum and Paracoccidioides brasiliensis.

Agaricus↗
PubMed1980

Cerebrospinal fluid lipids in demyelinating disease. I. Sphingolipids.

The lipid composition of CSF, serum and lymphocytes from patients without demyelinating disease (controls) as well as from patients with acute and chronic MS is analyzed. Individual lipid fractions are isolated by TLC and their fatty acid composition determined. Lipid and fatty acid composition of normal CSF resembles the results found in lymphocytes and it is deduced that CSF lipids are derived mainly from lymphocytes rather than white matter (myelin) or serum. There is an increase of CSF sphingomyelin in patients with acute MS (showing pleocytosis) which is apparently derived from disintegrated lymphocytes; there is also an increase of linoleic acid concentration which could come from serum because of dysfunction of the blood-brain barrier. The role of the CNS in contributing to CSF lipids is considered negligible both in controls and in patients with demyelination.

Demyelinating Diseases↗
PubMed1995

Fumonisin B1 alters sphingolipid metabolism and immune function in BALB/c mice: immunological responses to fumonisin B1.

Fumonisins have been reported to have diverse effects on animals, including immunosuppression in chickens and feeder calves; therefore, the effects of fumonisin B1 (FB1) on immune function in BALB/c mice was investigated. When administered i.p. with sheep red blood cells (SRBC), 5 to 100 micrograms of FB1 reduced the number of plaque-forming cells (PFC) produced against SRBC; however, when administered daily, 1 to 50 micrograms of FB1 caused a 4 to 12-fold increase in the number of PFC after SRBC injection. Therefore, FB1 is not only immunosuppressive; but also, immunostimulatory. To test the possibility that there may have been an immune response to FB1 as an antigen, FB1 was injected into mice and the number of splenic cells forming rosettes on FB1-treated SRBC was determined. There were dose-dependent increases in the antigen-binding cells, with up to 4.9- and 4.6-fold increases, respectively, upon primary and secondary immunization. FB1-binding immunoglobulins could be detected in sera from some treated mice, but this response was not obtained in every experiment. In summary, these results show that FB1 has diverse effects on the immune system, causing both stimulation and suppression of the response to foreign antigens, and apparently inducing an antigenic response to FB1.

Adjuvants, Immunologic↗