Ceramide induces interleukin 6 gene expression in human fibroblasts

Area of Science:

• Biochemistry
• Cell Biology
• Immunology

Background:

• Ceramide is a key product of sphingomyelin hydrolysis.
• Interleukin-1 beta (IL-1 beta) is a pro-inflammatory cytokine.
• Previous studies linked ceramide to IL-1 beta-mediated prostaglandin E2 production.

Purpose of the Study:

• To investigate the role of ceramide in interleukin-6 (IL-6) production.
• To determine if ceramide can induce IL-6 gene and protein expression in human fibroblasts.

Main Methods:

• Treatment of human fibroblasts with C2-ceramide, D-erythro-C2-ceramide, D-threo-C2-ceramide, and L-isomers of ceramide.
• Comparison of IL-6 induction by ceramide with IL-1 beta.
• Measurement of IL-6 messenger RNA (mRNA) and protein levels over time.
• Use of exogenous sphingomyelinase to induce ceramide production.

Main Results:

• Submicromolar concentrations of C2-ceramide induced IL-6 gene and protein production comparable to IL-1 beta.
• Both D-erythro-C2-ceramide and D-threo-C2-ceramide were potent inducers, while L-isomers were ineffective.
• Ceramide and sphingomyelinase treatments induced significant IL-6 levels within 6-24 hours.
• Ceramide-induced IL-6 mRNA was detectable within 1 hour and peaked by 24 hours.

Conclusions:

• Ceramide plays a significant role in the induction of IL-6 production.
• Ceramide may be a key regulator of IL-6 gene expression in response to inflammatory stimuli.
• These findings expand the known functions of ceramide in cellular signaling pathways.