Abstract
Inhibitors of cytosolic phospholipase A(2) (GIVA cPLA(2)) have received great attention, since this enzyme is involved in a number of inflammatory diseases, including cancer and auto-immune and neurodegenerative diseases. Traditionally, the effects of GIVA cPLA(2) inhibitors in cells have been studied by determining the inhibition of arachidonic acid release. However, although to a lesser extent, GIVA cPLA(2) may also hydrolyze glycerophospholipids, releasing other free fatty acids (FFAs), such as linoleic acid or oleic acid. In the present work, we applied a liquid chromatography-high-resolution mass spectrometry method to study the levels of intracellular FFAs, after treating cells with selected GIVA cPLA(2) inhibitors. Six inhibitors belonging to different chemical classes were studied, using SH-SY5Y neuroblastoma cells as a model. This lipidomic approach revealed that treatment with each inhibitor created a distinct intracellular FFA profile, suggesting not only inhibitory potency against GIVA cPLA(2), but also other parameters affecting the outcome. Potent inhibitors were found to reduce not only arachidonic acid, but also other long-chain FAs, such as adrenic or linoleic acid, even medium-chain FAs, such as caproic or caprylic acid, suggesting that GIVA cPLA(2) inhibitors may affect FA metabolic pathways in general. The downregulation of intracellular FFAs may have implications in reprogramming FA metabolism in neurodegenerative diseases and cancer.