Stimulation of Glycosphingolipid Biosynthesis by L-Threo-1-Phenyl-2-Decanoylamino-1-Propanol and Its Homologs in B16 Melanoma Cells

Inokuchi, Jin-ichi; Usuki, Seigou; Jimbo, Michio

doi:10.1093/oxfordjournals.jbchem.a124774

Cited by 27 publications

(21 citation statements)

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“…L-threo-PDMP, an isomer of D-threo-PDMP, was also studied. It stimulated ganglioside synthesis, increasing cellular ganglioside content from 3.95 Ϯ 0.39 to 5.06 Ϯ 0.64 (n ϭ 3) nmol of LBSA/mg of protein when the cells were exposed to 20 M L-PDMP for 6 days, which is consistent with a previous report (23). However, it had no effect on neurite formation, nor did it inhibit retinoic acidinduced neurite formation (Fig.…”

Section: Regulation Of Cellular Gangliosides By Retinoic Acid and D-psupporting

confidence: 92%

Inhibition of Endogenous Ganglioside Synthesis Does Not Block Neurite Formation by Retinoic Acid-treated Neuroblastoma Cells

Ladisch

1997

Journal of Biological Chemistry

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Gangliosides are believed to play a critical role in cellular differentiation. To test this concept, we determined the effect of inhibition of endogenous ganglioside synthesis upon neurite formation induced by retinoic acid in LAN-5 human neuroblastoma cells. Ganglioside synthesis and content of LAN-5 cells exposed for 6 days to 10 M D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) (an inhibitor of glucosylceramide synthase) were reduced by >90%. However, these ganglioside-depleted cells were not blocked from forming neurites when exposed to 10 M retinoic acid. Even more extensive treatment of LAN-5 cells with 20 M D-PDMP (6 day pretreatment followed by 6 days together with 10 M retinoic acid) still did not block the retinoic acid-induced neurite formation. An element of neuroblastoma tumor cell differentiation, neurite formation, is therefore dependent neither on an intact cellular ganglioside complement nor on new ganglioside synthesis.The high concentrations of gangliosides in the central nervous system have led to the widely held view that these molecules may play an important role in the differentiation of neuronal cells (1). There is evidence supporting this view, in that striking changes in ganglioside metabolism have been observed during both spontaneous and induced cellular differentiation (2-4). The treatment of LAN-5 human neuroblastoma cells with retinoic acid, which causes differentiation of the cells (5, 6), results in a marked increase in cellular ganglioside content (7). An increase in concentration of specific gangliosides (8), a switch in ganglioside biosynthetic pathways and the appearance of new gangliosides (9, 10), and changes in cellular ganglioside patterns (11) are generally considered to be important in the process of cellular differentiation, particularly in neuronal or neuroblastoma cells. Exogenous gangliosides also influence differentiation (12)(13)(14). However, the question of whether endogenous gangliosides are essential for cellular differentiation under physiological conditions remains to be answered.To determine whether endogenous gangliosides are essential for the process of cellular differentiation, we developed the following strategy. In a model system, the LAN-5 human neuroblastoma cell line, which can be induced by retinoic acid to differentiate and form neurites (5, 6), we studied the effect of cellular ganglioside depletion upon neurite formation. D-threo-1-Phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), 1 a potent inhibitor of glucosylceramide synthase (15, 16), was used to maximally inhibit ganglioside synthesis and deplete cellular ganglioside content. In this situation, despite downregulation of cellular ganglioside synthesis and content of LAN-5 cells, the formation of neurites induced by exposure of these cells to retinoic acid was not blocked. MATERIALS AND METHODS Preparation of Retinoic Acid, D-PDMP, and Nerve Growth FactorStock Solutions-Retinoic acid (all-trans form; Sigma) was dissolved in ethanol to a concentration of 10 Ϫ2 M and k...

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Section: Regulation Of Cellular Gangliosides By Retinoic Acid and D-psupporting

confidence: 92%

Inhibition of Endogenous Ganglioside Synthesis Does Not Block Neurite Formation by Retinoic Acid-treated Neuroblastoma Cells

Ladisch

1997

Journal of Biological Chemistry

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“…D -PDMP was initially suggested to be a selective inhibitor of GlcT-1 with an IC 50 of ∼10 µ M [23], but subsequent studies revealed that it also inhibits GalT-2 (with equal potency), two of the globo-series synthases [15], and the sialyltransferase that converts LacCer to ganglioside GM3 [24]. Treatment of NIH 3T3 fibroblasts or kidney proximal tubular cells with D -PDMP reduced the cellular levels of GlcCer and LacCer and increased the levels of Cer in a concentration- and time-dependent fashion [15, 25].…”

Section: Discussionmentioning

confidence: 99%

Lactosylceramide Mediates Shear-Induced Endothelial Superoxide Production and Intercellular Adhesion Molecule-1 Expression

Yeh

Kinsey

Chatterjee³

et al. 2001

J Vasc Res

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Laminar shear stress activates NADPH oxidase in vascular endothelial cells (ECs), and the generated superoxide radicals (O₂^–·) are known to be involved in intercellular adhesion molecule (ICAM)-1 expression. In this study, the role of a glycosphingolipid (GSL), lactosylceramide (LacCer), as a second messenger in the shear-induced O₂^–· generation and ICAM-1 expression was examined. It is known that glucosylceramide synthase (GlcT-1) catalyzes the synthesis of glucosylceramide (GlcCer) from ceramide, and subsequently lactosylceramide synthase (GalT-2) synthesizes LacCer from GlcCer. We observed that exposing cultured human umbilical vein ECs (HUVECs) to fluid shear stress (20 dyn/cm² for 30 min) activated GalT-2. Shear stress also increased EC O₂^–· generation, that peaked at 30 min, and surface ICAM-1 protein expression at 6 h post-shear. EC preincubation with the antioxidant N-acetylcysteine (NAC; 20 mM for 2 h) completely abolished the shear-induced O₂^–· production and significantly inhibited ICAM-1 expression. EC preincubation with D-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), an inhibitor of the GSL glycosyltransferases GlcT-1 and GalT-2, abrogated the shear-induced activation of GalT-2. D-PDMP also abolished the shear-induced O₂^–· production and ICAM-1 expression. We conclude that laminar shear stress activates GalT-2 to produce LacCer. In turn, LacCer activates NADPH oxidase, which produces O₂^–·, and O₂^–· mediates the shear-induced increase in ICAM-1 expression. Thus, LacCer may play an important role in hemodynamic force-induced pathological conditions, such as atherosclerosis and ischemia/reperfusion injury.

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“…H4APPsw cells were treated with L-PDMP, an activator of GCS (Inokuchi et al, 1995(Inokuchi et al, , 1997 in order to assess whether the inhibition of GSK3β activity observed in D-PDMP-treated cells might be linked to reduced cellular ganglioside levels. We first assessed that the enantiomer L-PDMP properly stimulated ganglioside synthesis in our experimental settings (Fig.…”

Section: L-pdmp Increases Ganglioside Content In H4appsw Cellsmentioning

confidence: 99%

Inhibition of GSK3β by pharmacological modulation of sphingolipid metabolism occurs independently of ganglioside disturbance in a cellular model of Alzheimer's disease

Noël

Ingrand

Barrier

2015

Experimental Neurology

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Stimulation of Glycosphingolipid Biosynthesis by L-Threo-1-Phenyl-2-Decanoylamino-1-Propanol and Its Homologs in B16 Melanoma Cells

Cited by 27 publications

References 0 publications

Inhibition of Endogenous Ganglioside Synthesis Does Not Block Neurite Formation by Retinoic Acid-treated Neuroblastoma Cells

Inhibition of Endogenous Ganglioside Synthesis Does Not Block Neurite Formation by Retinoic Acid-treated Neuroblastoma Cells

Lactosylceramide Mediates Shear-Induced Endothelial Superoxide Production and Intercellular Adhesion Molecule-1 Expression

Inhibition of GSK3β by pharmacological modulation of sphingolipid metabolism occurs independently of ganglioside disturbance in a cellular model of Alzheimer's disease

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