C6-ceramide enhances phagocytic activity of kupffer cells through the production of endogenous ceramides

Abstract

Ceramide has been suggested to be not only a tumorsuppressive lipid but also a regulator of phagocytosis. We examined whether exogenous cell-permeable C6-ceramide enhances the phagocytic activity of Kupffer cells (KCs) and affects the level of cellular ceramides. Rat KCs were isolated by collagenase digestion and differential centrifugation, using Percoll system. Phagocytic activity was measured by FACS analysis after incubating KCs with fluorescence-conjugated latex beads, and the level of cellular ceramide was analyzed by liquid chromatography tandem-mass spectrometry (LC-MS/MS). In this study we found that permeable C6-ceramide increases the cellular levels of endogenous ceramides via a sphingosine-recycling pathway leading to enhanced phagocytosis by KCs. © 2011 KSMCB.