Diacylglycerol in peripheral blood neutrophils from patients with localized juvenile periodontitis

Neutrophils from patients with localized juvenile periodontitis (LJP) show several functional abnormalities. Recently, it has become increasingly apparent that the reason for these changes lies in part at the post receptor level of cellular metabolism. In this study we have analyzed intracellular diacylglycerol (DAG), a second messenger and an endogenous activator of protein kinase C, in unstimulated and agonist-stimulated neutrophils, from five LJP patients showing a chemotaxis defect and matched normal individuals. No difference was observed in the basal cellular DAG between the two groups. In neutrophils from LJP patients the DAG levels increased by 67% and 111% from the basal level following stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP) and unopsonized zymosan particles, respectively, while in control cells the mean increases were 36% and 65%, respectively. Incubation with serum-opsonized zymosan particles produced an identical rise in DAG in both groups. These data indicate that the stimulation of receptors for FMLP and unopsonized zymosan may produce an enhanced accumulation of DAG in neutrophils from LJP patients. In addition to DAG mass analysis, we determined the effect of R59022, a DAG-kinase inhibitor, on zymosan-stimulated luminol-amplified chemiluminescence (CL) of neutrophils. In control cells R59022 significantly enhanced unopsonized zymosan induced CL, but it had no effect on cells from LJP patients, suggesting a possible change in the regulation of DAG-kinase in LJP.