Role of Ceramide from Glycosphingolipids and Its Metabolites in Immunological and Inflammatory Responses in Humans

Figure 3

Schematic mechanism of the production of inflammatory mediators by ceramide metabolites in human keratinocytes. PaCDase degrades ceramide into sphingosine in the stratum corneum, and sphingosine is converted to S1P by SphK of keratinocytes. S1P is then released extracellularly and binds to S1P receptors, resulting in the production and release of TNF-α. The released TNF-α binds to TNF-α receptors, activating NF-κB and inducing the production of IL-8 and endothelin-1.