Figure 6.

The roles of ceramides in the gut-liver axis. The figure mainly depicts the different mechanisms by which the different contents of the intestine can regulate ceramide synthesis. Gut microbiota can increase the risk of NAFLD through the synthesis of ceramide by uptake of palmitic acid and serine in the intestine and transfer to the liver via the portal vein to regulate sphingolipid metabolism in the liver. FXR and HIF-2α in the gut also regulate ceramide levels in the intestine and circulation.