Glucocerebroside inhibits NADPH oxidase activation in cell-free system

We reported earlier that monocytes and macrophages from patients with type I Gaucher disease have a decreased capacity to generate superoxide anion (O(2)(-)) on stimulation with opsonized S. aureus or formyl-methionyl-leucyl-phenylalanine. In this study, various forms of the cell-free assay system were used to probe the hypothesis that glucocerebroside (GC) accumulating in Gaucher patients' phagocytes may interfere with the activation of NADPH oxidase. Xanthine/xanthine oxidase assay was applied to explore the possibility that GC may scavenge O(2)(-). We found that addition of GC to the crude, semirecombinant or fully purified cell-free systems inhibited activation of NADPH oxidase in a concentration-dependent manner. The inhibitory effect of GC could be overcome by increased concentrations of p47(phox) and p67(phox). In contrast, O(2)(-) generation was not decreased by GC added to the assembled, catalytically active enzyme complex. In the xanthine/xanthine oxidase system, GC had no effect on the generation of O(2)(-). These data indicate that assembly of the respiratory burst oxidase of phagocytic cells may be a possible target of the pathologic actions of GC.