Human placenta sphingomyelinase, an exogenous acidic pH-optimum sphingomyelinase, induces oxidative stress, glutathione depletion, and apoptosis in rat hepatocytes

Garcı́a-Ruiz, Carmen; Marı́, Montserrat; Morales, Albert; Colell, Anna; Ardite, Esther; Fernández-Checa, José C.

doi:10.1053/jhep.2000.8267

Cited by 57 publications

(75 citation statements)

References 59 publications

(86 reference statements)

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“…Collectively, these data exclude C 6 -ceramide-mediated G 2 arrest as a result of DNA damage. Application of exogenous acidic SMase (ASMase; from human placenta) induced a transient elevation in endogenous ceramide (Figure 3a) as described elsewhere, 29 and was associated with a time-and dose-dependent arrest of RD cells in G 2 as determined from DNA cell cycle analysis (Figure 3a), BrdU incorporation (Figure 3b), phosphorylation of histone H3 (Figure 3c) and was associated with upregulation of p21 protein expression (Figure 3d). These observations were specific for ASMase since exogenous application of phospholipase C (PLC; from Bacillus cereus) or phospholipase D (PLD; from Steptomyces sp) did not modulate the cell cycle distribution of RD cells when used in the range 0-2 U/ml (data not shown).…”

Section: Resultsmentioning

confidence: 62%

Ceramide-induced G2 arrest in rhabdomyosarcoma (RMS) cells requires p21Cip1/Waf1 induction and is prevented by MDM2 overexpression

et al. 2007

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The sphingoplipid ceramide is responsible for a diverse range of biochemical and cellular responses including a putative role in modulating cell cycle progression. Herein, we describe that an accumulation of ceramide, achieved through the exogenous application of C 6 -ceramide or exposure to sphingomyelinase, induces a G 2 arrest in Rhabdomyosarcoma (RMS) cell lines. Utilizing the RMS cell line RD, we show that this G 2 arrest required the rapid induction of p21 Cip1/Waf1 independent of DNA damage. This was followed at later time points (48 h) by the commitment to apoptosis. Apoptosis was prevented by Bcl-2 overexpression, but permitted the maintenance of elevated p21 Cip1/Waf1 protein expression and the stabilization of the G 2 arrest response. Inhibition of p21 Cip1/Waf1 protein synthesis with cyclohexamide (CHX) or silencing of p21 Cip1/Waf1 with siRNA, prevented ceramide-mediated G 2 arrest and the late induction of apoptosis. Further, adopting the recent discovery that murine double minute 2 (MDM2) controls p21 Cip1/Waf1 expression by presenting this CDK inhibitor to the proteasome for degradation, RD cells overexpressing MDM2 abrogated ceramide-mediated p21 Cip1/Waf1 induction, G 2 arrest and the late ensuing apoptosis. Collectively, these data further support the notion that ceramide accumulation can modulate cell cycle progression. Additionally, these observations highlight MDM2 expression and proteasomal activity as key determinants of the cellular response to ceramide accumulation.

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Section: Resultsmentioning

confidence: 62%

Ceramide-induced G2 arrest in rhabdomyosarcoma (RMS) cells requires p21Cip1/Waf1 induction and is prevented by MDM2 overexpression

et al. 2007

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“…The increased nSMase activity in the hepatocytes of old rats is dependent on the glutathione depletion, while the increased aSMase activity in the liver cells can deplete the glutathione stores (Garcia-Ruiz et al 2000). However, it has been recently shown that generation of reactive oxygen species an important step for aSMase activation in cells (Dumitru and Gulbins 2006;Charruyer et al 2005).The aSMase could be activated by the protein kinase Cδ (PKCδ), which is overexpressed under oxidative stress (Zeidan and Hannun 2007) and a premature aging disorderWerner syndrome (Massip et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Vitamin E prevents the age-dependent and palmitate-induced disturbances of sphingolipid turnover in liver cells

Babenko

Hassouneh

Kharchenko

et al. 2011

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Sphingolipid turnover has been shown to be activated at old age and in response to various stress stimuli including oxidative stress. Reduction of vitamin E content in the liver under the pro-oxidant action is associated with enhanced sphingolipid turnover and ceramide accumulation in hepatocytes. In the present paper, the correction of sphingolipid metabolism in the liver cells of old rats and in the palmitate-treated young hepatocytes using α-tocopherol has been investigated. 3-and 24-month-old rats, [ 14 C] palmitic acid, [methyl− 14 C-choline]sphingomyelin (SM), and [ 14 C]serine were used. α-Tocopherol administration to old rats or addition to the culture medium of old liver slices or hepatocytes prevented age-dependent increase of ceramide synthesis and lipid accumulation, and increased SM content in liver tissue and cells. α-Tocopherol treatment of old cells decreased the neutral and acid sphingomyelinase (SMase) activities in hepatocytes and serine palmitoyl transferase activity in the liver cell microsomes. Effect of α-or γ-tocopherol, but not of δ-tocopherol, on the newly synthesized ceramide content in old cells was correlated with the action of inhibitor of serine palmitoyl transferase (SPT) activity (myriocin) and SMase inhibitors (glutathione, imipramine). Addition of α-tocopherol as well as myriocin to the culture medium of young hepatocytes, treated by palmitate, abolished ceramide accumulation and synthesis. The data obtained demonstrate that α-tocopherol normalized elevated ceramide content in the old liver cells via inhibition of acid and neutral SMase activities and lipid synthesis de novo. α-Tocopherol, reducing ceramide synthesis, prevented palmitate-induced aging-like ceramide accumulation in young liver cells.

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“…Mg 2ϩ -dependent NSMase and ASMase activities were determined from [N-methyl- 14 C]sphingomyelin (56.6 mCi/mmol, Amersham Biosciences, Piscataway, NJ) as described. 27 CDase activities were measured using 5 mol/L [ 14 C]ceramide (55 mCi/ mmol, ARC, St. Louis, MO) or C 12 -NBD ceramide (Molecular Probes, Eugene, OR) in 10 mmol/L Tris-HCl, pH 8.0 for the neutral/alkaline CDase or 0.5 mol/L acetate buffer, pH 4.5, for the acid CDase. 21,28 The GCS and SMS were determined as described previously.…”

Section: Methodsmentioning

confidence: 99%

Critical role of acidic sphingomyelinase in murine hepatic ischemia-reperfusion injury

et al. 2006

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The molecular mechanisms of hepatic ischemia/reperfusion (I/R) damage are incompletely understood. We investigated the role of ceramide in a murine model of warm hepatic I/R injury. This sphingolipid induces cell death and participates in tumor necrosis factor (TNF) signaling. Hepatic ceramide levels transiently increased after the reperfusion phase of the ischemic liver in mice, because of an early activation of acidic sphingomyelinase (ASMase) followed by acid ceramidase stimulation. In vivo administration of an ASMase inhibitor, imipramine, or ASMase knockdown by siRNA decreased ceramide generation during I/R, and attenuated serum ALT levels, hepatocellular necrosis, cytochrome c release, and caspase-3 activation. ASMase-induced ceramide generation activated JNK resulting in Bim L phosphorylation and translocation to mitochondria, as the inhibition of ASMase by imipramine prevented these events. In contrast, blockade of ceramide catabolism by N-oleyolethanolamine (NOE), a ceramidase inhibitor, enhanced ceramide levels and potentiated I/R injury compared with vehicle-treated mice. Pentoxifylline treatment prevented TNF upregulation and ASMase activation. Furthermore, 9 of 11 mice treated with imipramine survived 7 days after total liver ischemia, compared with 4 of 12 vehicle-treated mice, whereas 8 of 8 NOE-treated mice died within 2 days of total liver ischemia. In conclusion, ceramide generated from ASMase plays a key role in I/R-induced liver damage, and its modulation may be of therapeutic relevance.

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Human placenta sphingomyelinase, an exogenous acidic pH-optimum sphingomyelinase, induces oxidative stress, glutathione depletion, and apoptosis in rat hepatocytes

Cited by 57 publications

References 59 publications

Ceramide-induced G2 arrest in rhabdomyosarcoma (RMS) cells requires p21Cip1/Waf1 induction and is prevented by MDM2 overexpression

Ceramide-induced G2 arrest in rhabdomyosarcoma (RMS) cells requires p21Cip1/Waf1 induction and is prevented by MDM2 overexpression

Vitamin E prevents the age-dependent and palmitate-induced disturbances of sphingolipid turnover in liver cells

Critical role of acidic sphingomyelinase in murine hepatic ischemia-reperfusion injury

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