Stress‐induced apoptosis is not mediated by endolysosomal ceramide

• Published in: The FASEB journal 2000-01, Vol.14 (1), p.36-47
• Main Authors: SéGUI, BRUNO, BEZOMBES, CHRISTINE, URO‐COSTE, EMMANUELLE, MEDIN, JEFFREY A., ANDRIEU‐ABADIE, NATHALIE, AUGé, NATHALIE, BROUCHET, ANNE, LAURENT, GUY, SALVAYRE, ROBERT, JAFFRéZOU, JEAN‐PIERRE, LEVADE, THIERRY
• Format: Article
• Language: English
• Subjects: Apoptosis - drug effects; Apoptosis - physiology; Apoptosis - radiation effects; CD40 Antigens - pharmacology; Cell Line, Transformed; Cell Survival; ceramidase; Ceramides - physiology; Daunorubicin - pharmacology; Farber disease; fas Receptor - pharmacology; Humans; Hydrogen-Ion Concentration; Hydrolysis; Lysosomal Storage Diseases - metabolism; Lysosomal Storage Diseases - pathology; lysosome; Lysosomes - metabolism; Signal Transduction; sphingomyelin; sphingomyelinase; Sphingomyelins - metabolism; Stress, Physiological - pathology; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.14.1.36

ABSTRACT A major lipid‐signaling pathway in mammalian cells implicates the generation of ceramide from the ubiquitous sphingolipid sphingomyelin (SM). Hydrolysis of SM by a sphingomyeli‐nase present in acidic compartments has been reported to mediate, via the production of cer‐amide, the apoptotic cell death triggered by stress‐inducing agents. In the present study, we investigated whether the ceramide formed within or accumulated in lysosomes indeed triggers apopto‐sis. A series of observations strongly suggests that ceramide involved in stress‐induced apoptosis is not endolysosomal: 1) Although short‐chain cer‐amides induced apoptosis, loading cells with natural ceramide through receptor‐mediated endocy‐tosis did not result in cell death. 2) Neither TNF‐α nor anti‐CD95 induced the degradation to ceramide of a natural SM that had been first introduced selectively into acidic compartments. 3) Stimulation of SV40‐transformed fibroblasts by TNF‐α or CD40 ligand resulted in apoptosis equally well in cells derived from control individuals and from patients affected with Farber disease, having a genetic defect of acid ceramidase activity leading to lysosomal accumulation of cer‐amide. Also, induction of apoptosis using anti‐CD95 (Fas) or anti‐CD40 antibodies, TNF‐α, daunorubicin, and ionizing radiation was similar in control and Farber disease lymphoid cells. In all cases, apoptosis was preceded by a comparable increase of intracellular ceramide levels. 4) Retro‐viral‐mediated gene transfer and overexpression of acid ceramidase in Farber fibroblasts, which led to complete metabolic correction of the ceramide catabolic defect, did not affect the cell response to TNF‐α and CD40 ligand.—Ségui, B., Bezombes, C., Uro‐Coste, E., Medin, J. A., Andrieu‐Abadie, N., Augé, N., Brouchet, A., Laurent, G., Salvayre, R., Jaffrézou, J.‐P., Levade, T. Stress‐induced apoptosis is not mediated by endolysosomal ceramide. FASEB J. 14, 36–47(2000)