A ceramide analogue inhibits T cell proliferative response through inhibition of glycosphingolipid synthesis and enhancement of N,N-dimethylsphingosine synthesis.
The ceramide analogue 1-phenyl-2-(decanoylamino)-3-morpholino-1-propanol (PDMP) (particularly the D-threo isomer, D-PDMP) caused inhibition of cell growth in some types of cells, and this growth-inhibitory effect has been attributed to inhibition of UDP-Glc:Cer beta-Glc transferase, resulting in reduced glycolipid synthesis and increased free ceramide [Inokuch, J., & Radin, N. S. (1987) J. Lipid Res. 28, 565-571; Okada, Y., et al. (1988) FEBS Lett. 235, 25-29]. In view of increasing evidence that the T cell proliferative immune response is modulated by glycosphingolipids (GSLs), the reagent D-PDMP was used to evaluate the role of GSLs in this respect. Con A induced or PHA-induced mitogenesis of C3H/HeJ mouse splenocytes, as well as IL2-dependent CTLL cell growth, were strongly inhibited in a dose-dependent manner when cells were preincubated in the presence of 5-10 microM D-PDMP, but not with its stereoisomer L-PDMP. Closely associated with this growth-inhibitory effect in the presence of D-PDMP, levels of essentially all GSLs, including GM3 and other gangliosides, were greatly reduced, whereas ceramide accumulated. Importantly, metabolically labeled radioactive bands, corresponding to free sphingosine and N-monomethylsphingosine, were found to be present in very small quantities (5-12%) relative to the band corresponding to N,N-dimethylsphingosine (DMS), which showed significant accumulation in D-PDMP-treated lymphocytes. The quantity of IL2 receptors and their affinity to IL2 on T cells did not change, but IL2-dependent tyrosine phosphorylation was greatly stimulated, following D-PDMP treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Biomembrane Institute, Seattle, Washington 98119.
B
B
Felding-Habermann
Y
Y
Igarashi
B A
BA
Fenderson
L S
LS
Park
N S
NS
Radin
J
J
Inokuchi
G
G
Strassmann
K
K
Handa
S
S
Hakomori
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002518:Ceramides / Q000032:analysis; D004261:DNA Replication / Q000187:drug effects; D005732:Gangliosides / Q000032:analysis; D006028:Glycosphingolipids / Q000096:biosynthesis*; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008809:Mice, Inbred C3H; D009025:Morpholines / Q000494:pharmacology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000032:analysis; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D013237:Stereoisomerism; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects*
D002518:Ceramides; D005732:Gangliosides; D006028:Glycosphingolipids; D007376:Interleukin-2; D009025:Morpholines; D010835:Phytohemagglutinins; D015375:Receptors, Interleukin-2; C033110:RV 538; D011505:Protein-Tyrosine Kinases; C061800:N,N-dimethylsphingosine; D013110:Sphingosine