Crocin prevents the death of PC-12 cells through sphingomyelinase-ceramide signaling by increasing glutathione synthesis.
Crocin is a pharmacologically active component of Crocus sativus L. (saffron) that has been used in traditional Chinese medicine. In a previous study, we demonstrated that crocin inhibits apoptosis in PC-12 cells by affecting the function of tumor necrosis factor-alpha. In this study, we found that depriving cultured PC-12 cells of serum/glucose causes a rapid increase in cellular ceramide levels, followed by an increase in the phosphorylation of c-jun kinase (JNK). The accumulation of ceramide was found to depend on the activation of magnesium-dependent neutral sphingomyelinase (N-SMase), but not on de novo synthesis. The serum/glucose-deprived PC-12 cells also decreased the cellular levels of glutathione (GSH), which is the potent inhibitor of N-SMase. Treating the PC-12 cells with crocin prevented N-SMase activation, ceramide production, and JNK phosphorylation. We also found that the chemical can enhance the activities of GSH reductase and gamma-glutamylcysteinyl synthase (gamma-GCS), contributing to a stable GSH supply that blocks the activation of N-SMase. Thus our data suggest that crocin combats the serum/glucose deprivation-induced ceramide formation in PC-12 cells by increasing GSH levels and prevents the activation of JNK pathway, which is reported to have a role of the signaling cascade downstream ceramide for neuronal cell death.
Ochiai
Takashi
T
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
Soeda
Shinji
S
Ohno
Shigekazu
S
Tanaka
Hiroyuki
H
Shoyama
Yukihiro
Y
Shimeno
Hiroshi
H
D019881:Aminoacyltransferases / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D002338:Carotenoids / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002518:Ceramides / Q000378:metabolism / Q000502:physiology*; D016895:Culture Media, Serum-Free; D005947:Glucose / Q000502:physiology; D005978:Glutathione / Q000096:biosynthesis*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D007202:Indicators and Reagents; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D016716:PC12 Cells; D010766:Phosphorylation; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism / Q000502:physiology*
D002518:Ceramides; D016895:Culture Media, Serum-Free; D007202:Indicators and Reagents; D012333:RNA, Messenger; D002338:Carotenoids; C029036:crocin; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D019881:Aminoacyltransferases; C093784:glutathione gamma-glutamylcysteinyltransferase; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D013108:Sphingomyelin Phosphodiesterase; D005978:Glutathione; D005947:Glucose