Phosphatidylcholine metabolism is altered in a monocyte-derived macrophage model of Gaucher disease but not in lymphocytes.

Gaucher disease is caused by defective activity of acid-beta-glucosidase (GlcCerase), resulting in accumulation of glucosylceramide (GlcCer) mainly in macrophages. We now demonstrate that secondary biochemical pathways regulating levels of phospholipid metabolism are altered in a Gaucher disease macrophage model. Upon treatment of macrophages with the GlcCerase inhibitor, conduritol-B-epoxide, phosphatidylcholine (PC) labeling with the metabolic precursor, [methyl-14C]choline, was elevated after 6 or 12 days in macrophages but not in lymphocytes. These changes correlated with increases in the cytoplasmic/nuclear ratio and with levels of [3H]GlcCer accumulation. Moreover, metabolic labeling with L-[3-3H]serine and L-[methyl-3H]methionine demonstrated that PC synthesis via the methylation of phosphatidylethanolamine is also increased in CBE-treated macrophages. Since PC is a major structural component of biological membranes and the source of various second messengers, we suggest that changes in its metabolism in macrophages may be relevant for understanding Gaucher disease pathology.