Send to

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 2002 Aug 23;277(34):30784-91. Epub 2002 Jun 18.

Ceramide mediates age-associated increase in macrophage cyclooxygenase-2 expression.

Author information

Nutritional Immunology Laboratory, Jean Mayer United States Department of Agriculture/Human Nutrition Research Center at Tufts University, 711 Washington Street, Boston, MA 02111.


Previously, we showed that macrophages (MØ) from old mice have significantly higher levels of lipopolysaccharide (LPS)-induced prostaglandin E(2) (PGE(2)) production than young mice, due to increased cyclooxygenase-2 (COX-2) mRNA levels. The aim of the current study was to determine the underlying mechanisms of age-associated increase in COX-2 gene expression. The results demonstrate that increased COX-2 mRNA expression in the old mice is due to a higher rate of transcription rather than increased stability of COX-2 mRNA. Furthermore, the results show that LPS-induced ceramide levels from the old mice are significantly higher than those of young mice, whereas there is no age-related difference in concentration of its down stream metabolite, sphingosine. The addition of ceramide in the presence or absence of LPS resulted in a significant increase in PGE(2) production in a dose- and time-dependent manner. Inhibition of ceramide conversion to sphingosine had no effect on this ceramide-induced effect. The ceramide-induced up-regulation in PGE(2) production was mediated through increase in COX activity and transcriptional up-regulation of COX-2 mRNA. Collectively, these data suggest that the age-associated increase in MØ COX-2 mRNA is due to transcriptional up-regulation. Furthermore, this increase in transcription is mediated by higher cellular ceramide concentration in old MØ compared with that of young MØ.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons


    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center