Hepatic GDP-fucose transporter SLC35C1 attenuates cholestatic liver injury and inflammation by inducing CEACAM1 N153 fucosylation

Background and aims: Inflammatory response is crucial for bile acid (BA)-induced cholestatic liver injury, but molecular mechanisms remain to be elucidated. Solute Carrier Family 35 Member C1 (SLC35C1) can transport Guanosine diphosphate-fucose into the Golgi to facilitate protein glycosylation. Its mutation leads to the deficiency of leukocyte adhesion and enhances inflammation in humans. However, little is known about its role in liver diseases.

Approach and results: Hepatic SLC35C1 mRNA transcripts and protein expression were significantly increased in patients with obstructive cholestasis and mouse models of cholestasis. Immunofluorescence revealed that the upregulated SLC35C1 expression mainly occurred in hepatocytes. Liver-specific ablation of Slc35c1 ( Slc35c1 cKO ) significantly aggravated liver injury in mouse models of cholestasis induced by bile duct ligation and 1% cholic acid-feeding, evidenced by increased liver necrosis, inflammation, fibrosis, and bile ductular proliferation. The Slc35c1 cKO increased hepatic chemokine Ccl2 and Cxcl2 expression and T cell, neutrophil, and F4/80 macrophage infiltration but did not affect the levels of serum and liver BA in mouse models of cholestasis. Liquid chromatography with tandem mass spectrometry analysis revealed that hepatic Slc35c1 deficiency substantially reduced the fucosylation of cell-cell adhesion protein CEACAM1 at N153. Mechanistically, cholestatic levels of conjugated BAs stimulated SLC35C1 expression by activating the STAT3 signaling to facilitate CEACAM1 fucosylation at N153, and deficiency in the fucosylation of CEACAM1 at N135 enhanced the BA-stimulated CCL2 and CXCL2 mRNA expression in primary mouse hepatocytes and Primary Liver Carcinoma/Poliomyelitis Research Foundation/5- ASBT cells.

Conclusions: Elevated hepatic SLC35C1 expression attenuates cholestatic liver injury by enhancing CEACAM1 fucosylation to suppress CCL2 and CXCL2 expression and liver inflammation.