Cytosolic phospholipase A 2-driven PGE 2 synthesis within unsaturated fatty acids-induced lipid bodies of epithelial cells

Abstract

Cytoplasmic lipid bodies (also known as lipid droplets) are intracellular deposits of arachidonic acid (AA), which can be metabolized for eicosanoid generation. PGE 2 is a major AA metabolite produced by epithelial cells and can modulate restoration of epithelium homeostasis after injury. We studied lipid body biogenesis and their role in AA metabolic pathway in an epithelial cell line derived from normal rat intestinal epithelium, IEC-6 cells. Lipid bodies were virtually absent in confluent IEC-6 cells. Stimulation of confluent IEC-6 cells with unsaturated fatty acids, including AA or oleic acid (OA), induced rapid lipid body assembly that was independent on its metabolism to PGE 2, but dependent on G-coupled receptor-driven signaling through p38, PKC, and PI3K. Newly formed lipid bodies compartmentalized cytosolic phospholipase (cPL)A 2-α, while facilitated AA mobilization and synthesis of PGE 2 within epithelial cells. Thus, both lipid body-related events, including highly regulated biogenesis and functional assembly of cPLA 2-α-driven enhanced AA mobilization and PGE 2 production, may have key roles in epithelial cell-driven inflammatory functions, and may represent relevant therapeutic targets of epithelial pathologies.