Expression of mRNAs for the diacylglycerol kinase family in immune cellsduring an inflammatory reaction

抄録

Phosphoinositide metabolism is intimately involved in cellular signal transduction. In response toextracellular stimuli, it generates diacylglycerol (DG), which serves as a lipid second messengermolecule to activate various proteins in various organs under pathophysiological conditions. Diacylglycerolkinase (DGK) constitutes an enzyme family that catalyzes conversion of DG to phosphatidicacid. It is therefore regarded as a regulator of the DG signal. Previous studies haverevealed the critical role of α and ζ types of DGK in T cell functions. Nevertheless, little is knownabout the expression patterns of the DGK family in immune cells of various kinds. After examinationof the expression profile of DGK isozymes in immune cells that are isolated from humanblood, we investigated whether their mRNA expression levels would be changed during an inflammatoryreaction. Results showed that DGK isozyme mRNAs are widely expressed in immunecells, except for DGKβ and DGKι. During an inflammatory reaction, DGKε mRNA was increasedtransiently in the initial phase (20–40 min) of stimulation with both LPS and IL-2 in T cellderivedHUT-102 cells and macrophage-derived RAW264 cells. At the organismal level, an intraperitonealinjection of LPS also induced upregulation of DGKε mRNA in the spleen in a similar,but not identical, manner. These results suggest that DGKε is involved in inflammatory processesof the cellular immune system.