The Role of Sulfatides in Liver Health and Disease.

Sulfatides or 3-O-sulfogalactosylceramide are negatively charged sulfated glycosphingolipids abundant in the brain and kidneys and play crucial roles in nerve impulse conduction and urinary pH regulation. Sulfatides are present in the liver, specifically in the biliary tract. Sulfatides are self-lipid antigens presented by cholangiocytes to activate cluster of differentiation 1d (CD1d)-restricted type II natural killer T (NKT) cells. These cells are involved in alcohol-related liver disease (ArLD) and ischemic liver injury and exert anti-inflammatory effects by regulating the activity of pro-inflammatory type I NKT cells. Loss of sulfatides has been implicated in the chronic inflammatory disorder of the liver known as primary sclerosing cholangitis (PSC); bile ducts deficient in sulfatides increase their permeability, resulting in the spread of bile into the liver parenchyma. Previous studies have shown elevated levels of sulfatides in hepatocellular carcinoma (HCC), where sulfatides could act as adhesive molecules that contribute to cancer metastasis. We have recently demonstrated how loss of function of GAL3ST1, a limiting enzyme involved in sulfatide synthesis, reduces tumorigenic capacity in cholangiocarcinoma (CCA) cells. The biological function of sulfatides in the liver is still unclear; however, this review aims to summarize the existing findings on the topic.