• YoungJun Ju, Ashley Untereiner, Lingyun Wu, and Guangdong Yang.
• Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, ON P7B 5E1, Canada.
• Biochim. Biophys. Acta. 2015 Nov 1; 1850 (11): 2293-303.

BackgroundCystathionine gamma-lyase (CSE)-derived hydrogen sulfide (H(2)S) possesses diverse roles in the liver, affecting lipoprotein synthesis, insulin sensitivity, and mitochondrial biogenesis. H(2)S S-sulfhydration is now proposed as a major mechanism for H(2)S-mediated signaling. Pyruvate carboxylase (PC) is an important enzyme for gluconeogenesis. S-sulfhydration regulation of PC by H(2)S and its implication in gluconeogenesis in the liver have been unknown.MethodsGene expressions were analyzed by real-time PCR and western blotting, and protein S-sulfhydration was assessed by both modified biotin switch assay and tag switch assay. Glucose production and PC activity was measured with coupled enzyme assays, respectively.ResultsExogenously applied H(2)S stimulates PC activity and gluconeogenesis in both HepG2 cells and mouse primary liver cells. CSE overexpression enhanced but CSE knockout reduced PC activity and gluconeogenesis in liver cells, and blockage of PC activity abolished H(2)S-induced gluconeogenesis. H(2)S had no effect on the expressions of PC mRNA and protein, while H(2)S S-sulfhydrated PC in a dithiothreitol-sensitive way. PC S-sulfhydration was significantly strengthened by CSE overexpression but attenuated by CSE knockout, suggesting that H(2)S enhances glucose production through S-sulfhydrating PC. Mutation of cysteine 265 in human PC diminished H(2)S-induced PC S-sulfhydration and activity. In addition, high-fat diet feeding of mice decreased both CSE expression and PC S-sulfhydration in the liver, while glucose deprivation of HepG2 cells stimulated CSE expression.ConclusionsCSE/H(2)S pathway plays an important role in the regulation of glucose production through S-sulfhydrating PC in the liver.General SignificanceTissue-specific regulation of CSE/H(2)S pathway might be a promising therapeutic target of diabetes and other metabolic syndromes.Copyright © 2015 Elsevier B.V. All rights reserved.

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