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Lysophosphatidic acid (LPA) exerts a variety of biological responses through specific receptors: three subtypes of the EDG-family receptors, LPA1, LPA2, and LPA3 (formerly known as EDG-2, EDG-4, and EDG-7, respectively), and LPA4/GPR23, structurally distinct from the EDG-family receptors, have so far been identified. In the present study, we characterized(More)
OBJECTIVE Sphingomyelin deposition and metabolism occurs in the atherosclerotic plaque, leading to the formation of sphingosine-1-phosphate (S1P), which activates G protein-coupled receptors to regulate vascular and immune cells. The role of S1P receptors in atherosclerosis has not been examined. METHODS AND RESULTS We tested the hypothesis that S1P(More)
Macrophage recruitment to sites of inflammation is an essential step in host defense. However, the mechanisms preventing excessive accumulation of macrophages remain relatively unknown. The lysophospholipid sphingosine 1-phosphate (S1P) promotes T and B cell egress from lymphoid organs by acting on S1P receptor 1 (S1P(1)R). More recently, S1P(5)R was shown(More)
The sphingosine 1-phosphate receptor 1 (S1P(1)) promotes lymphocyte egress from lymphoid organs. Previous work showed that agonist-induced internalization of this G protein-coupled receptor correlates with inhibition of lymphocyte egress and results in lymphopenia. However, it is unclear if S1P(1) internalization is necessary for this effect. We(More)
Ginseng has an anti-cancer effect in several cancer models. This study was to characterize active constituents of ginseng and their effects on proliferation of prostate cancer cell lines, LNCaP and PC3. Cell proliferation was measured by [3H]thymidine incorporation, the intracellular calcium concentration by a dual-wavelength spectrophotometer system,(More)
Globoid cell leukodystrophy (GLD) is characterized histopathologically by apoptosis of oligodendrocytes, progressive demyelination, and the existence of large, multinuclear (globoid) cells derived from perivascular microglia. The glycosphingolipid, psychosine (d-galactosyl-beta-1,1' sphingosine), accumulates to micromolar levels in GLD patients who lack the(More)
Recently, two different chemicals have been matched as ligands with the same G-protein-coupled receptor (GPCR). Double-pairing of OGR1 family GPCRs with proton and lysolipid raises several questions. First, whether both are the real ligands for the GPCRs. Second, whether modulation of a GPCR by two chemicals could be possible. Third, one of the chemicals is(More)
Ginseng, the root of Panax ginseng, has been used in traditional Chinese medicine as a tonic herb that provides many beneficial effects. Pharmacologic studies in the last decades have shown that ginsenosides (ginseng saponins) are primarily responsible for the actions of ginseng. However, the effects of ginseng are not fully explained by ginsenosides.(More)
AIM To understand the contribution of sphingolipid metabolism and its metabolites to development and aging. METHODS A systemic analysis on the changes in activity of sphingolipid metabolic enzymes in kidney, liver and brain tissues during development and aging was conducted. The study was conducted using tissues from 1-day-old to 720-day-old rats. (More)
Previous studies on lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) using various approaches have shown that both the molecules can act as intercellular signaling molecules. The discovery of the Edg subfamily of G-protein-coupled receptors (GPCRs) (later renamed LPA(1-3) and S1P(1-5)) for these molecules has opened up a new avenue for(More)