• Archives of Pharmacal Research
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• 제24권2호
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• pp.144-149
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• 2001

N-acetylsphingosine (C2-ceramide) is a synthetic water-soluble ceramide mimicking the activity of natural ceramides. By fixing chiral conformation on carbon numbers 2 and 3 in the ceramide structure, four chiral C2-ceramides naming d-erythro-, I-erythro-, d-threo-and 1-three C2-ceramide were synthesized. We have investigated the chiral effects of these C2-ceramides on the sphingolipid metabolism, particularly on both the sphingolipid bio- synthetic pathway and on the degradation pathway. In both HL-60 and U937 cells, the chiral C2-ceramide ($10{\mu}\textrm{m}$) showed sphingosine accumulation monitored fluoromatrically by a high performance liquid chromatographic separation of the sphingoid bases. Most importantly, in HL-60 cells, l-erythro C2-ceramide induced a 50 fold increase in sphingosine as compared to the control, while l-threo C2-ceramide exhibited a minimal 7-fold in-crease. In contrast, sphinganine, another sphingoid base, showed less accumulation by any chiral C2-ceramide tested under the same conditions. These results suggested that chiral C2-ceramide primarilyacts on the sphingolipid degradation pathway rather than on the sphingolipid biosynthetic route. The strong $C_0/G_1$ phase arrest in the cell cycle by treatment of I-erythro C2-ceramide indicates that the blockade of the sphingolipid degradation pathway might be concomitantly involved in the dysfunction of the cell cycle. On the other hand, the fact that all chiral C2-ceramides tested failed to inhibit the activity of sphingosine kinase acting on the removal of sphingosine by producing sphingosine-1 -phosphate demonstrates that chiral C2- ceramides may increase sphingosine by activating various ceramidases by which natural ceramides are divided into sphingosine and free fatty acids. However, the precise steps involved in this interaction are still unknown.

• Journal of Nutrition and Health
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• 제45권2호
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• pp.113-120
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• 2012

In our previous studies, dietary supplements of silk protein, sericin, and fibroin, were beneficial for improving epidermal levels of ceramides, which are the major lipids for maintaining the epidermal barrier. In this study, we investigated the dietary effects of silk protein on epidermal levels of free sphingoid bases and their phosphates such as $C_{18}$ sphingosine (So), $C_{18}$ sphinganine (Sa), $C_{18}$ sphingosine-1-phosphate (S1P), and $C_{18}$ sphinganine-1-phosphate (Sa1P), which are either synthetic substrate or degradative metabolites of ceramides. Forty-five male NC/Nga mice, an animal model of atopic dermatitis (AD), were divided into three groups: group CA was an atopic control and fed a control diet, group S was fed a 1% sericin diet, and group F was fed a 1% fibroin diet. Fifteen male BALB/c mice served as group C (control group) and were fed the control diet. All mice were fed with diets and water $ad$ $libitum$ for 10 weeks. Sa in group CA was lower than that in group C, but So in group CA was similar to that in group C. So and Sa were higher in groups S and F than those in group CA; So level was even higher than that in group C, and Sa level was similar to that of group C. The So/Sa ratio in group CA, which is reported to increase in AD, was significantly higher than that of group C. The So/Sa ratio was lower in groups S and F than that in group CA, and decreased further in group F. However, S1P and Sa1P in groups S and F were similar to those in group CA. Taken together, we demonstrated that silk protein, sericin and fibroin dietary supplements, increased So and Sa levels, and decreased the So/Sa ratio.

• BMB Reports
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• 제50권3호
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• pp.144-149
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• 2017

Ceramides are the major sphingolipid metabolites involved in cell survival and apoptosis. When HepG2 hepatoma cells were treated with celecoxib, the expression of the genes in de novo sphingolipid biosynthesis and sphingomyelinase pathway was upregulated and cellular ceramide was elevated. In addition, celecoxib induced endoplasmic reticulum (ER) stress in a time-dependent manner. SPTLC2, a subunit of serine palmitoyltransferase, was overexpressed by adenovirus. Adenoviral overexpression of SPTLC2 (AdSPTLC2) decreased cell viability of HEK293 and HepG2 cells. In addition, AdSPTLC2 induced apoptosis via the caspase-dependent apoptotic pathway and elevated cellular ceramide, sphingoid bases, and dihydroceramide. However, overexpression of SPTLC2 did not induce ER stress. Collectively, celecoxib activates de novo sphingolipid biosynthesis and the combined effects of elevated ceramide and transcriptional activation of ER stress induce apoptosis. However, activation of de novo sphingolipid biosynthesis does not activate ER stress in hepatoma cells and is distinct from the celecoxib-mediated activation of ER stress.

• Mass Spectrometry Letters
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• 제15권1호
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• pp.49-53
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• 2024

Ceramide is a lipid in which sphingoid bases and fatty acids are linked by amide bonds. As a marker of skin disease in the human stratum corneum, its disease-causing and therapeutic effects have been partially confirmed, and it is therefore an important element in commercially available cosmetic formulations. However, structural diversity caused by differences in the chain length, number, and location of hydroxyl groups makes quality control difficult. In this study, a method was established to separate different ceramide species using reversed-phase LC-MS/MS and thus enable qualitative evaluation. Separation of four standards was achieved within a short retention time, and the accuracy and sensitivity of the method were demonstrated by the low limit of detection (LOD) calculated based on the calibration curve showing linearity, with R² > 0.994. After verification of reproducibility and reliability through intra- and inter-day analyses, the efficiency of the method was confirmed through analysis of commercial cosmetic raw materials.

• 분석과학
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• 제7권4호
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• pp.547-554
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• 1994

국내 자생 담자균, Phellinus ribis부터 ceramide 성분들이 존재함을 확인하고 실리카 컬럼크로마토그래피를 이용하여 분리하고 prep.-TLC로 재차 정제한 다음, 그 구조 및 조성을 검토하였다. FAB-MS 및 GC-MS를 이용하여 그 구성성분을 분석한 결과 지방산 주성분은 hydroxy fatty acid($C_{22:0}$, $C_{25:0}$, $C_{24:0}$, $C_{23:0}$)이고 sphingoid 염기는 (tri-hydroxy-sphinganine 및 동족계열의 아민으로 확인되었다.

• Toxicological Research
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• 제11권1호
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• pp.1-8
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• 1995

Fumonisins are a family of mycotoxins produced by the fungus Fusarium moniliforme which is a common contaminant in corn. Fumonisins are potent inhibitors of sphingosine and sphinganine N-acyltransferase (ceramide synthase), key enzymes in sphingolipid metabolism. The purpose of this study was to provide the evidence that the elevated levels of free sphingoid bases (primarily sphinganine) and depletion of complex sphingolipids were closely related to the inhibition of cell growth in LLC-$PK_1$ cells exposed to fumonisin $B_1$$(\leq 35 {\mu}M)$. Concentrations of fumonisin $B_1$ between 10 and $35 {\mu}M$ were known to inhibit cell growth without cytotoxicity in $LLC-PK_1$ cells (Yoo et al. Toxicol. Appl. Pharmacol. 114, 9-15, 1992). Cells exposed to 35$\mu M$ fumonisin B$_1$ for 48 and 72 hr developed a fibroblast-like (elongated and spindle-shaped) appearance and were less confluent than normal cells. At between 24 and 48 hr after exposure to fumonisin $B_1$ cells were beginning to show the inhibition of cell growth and at 72 hr the number of viable cells in fumonisin-treated cultures was about 50% of concurrent control cultures. During the 24 hr lag period preceding inhibition of cell growth, the free sphinganine levels in cells exposed to $35 {\mu}M$ fumonisin $B_1$ were highly elevated (approximately 230 fold higher than normal cells). The elevated levels of free sphinganine were $435\pm14$$pmoles/{10^6}$ cells at 48 hr and approximately TEX>$333\pm11$$pmoles/{10^6}$ cells in cells exposed to $35{\mu}M$ fumonisin$B_1$ at 72 hr, while the levels of free sphinganine in normal cells were less than 2$pmoles/{10^6}$ cells. Under the same condition, depletion of intracellular complex sphingolipids as a consequence of fumonisin inhibition of de novo sphingolipid biosynthesis and turnover pathway was appeared. Content of free sphingold bases in dividing cells was more elevated than in confluent cells at 24-48 hr after cells were exposed to $20{\mu}M$ fumonisin $B_1$. The dividing cells were showing the inhibition of cell growth at 48-72 hr and $20{\mu}M$ fumonisin $B_1$. The results of this study support the hypothesis that the inhibition of cell growth is very well related to the disruption of sphingolipid metabolism in $LLC-PK_1$ cells.