H2S-induced S-sulfhydration of pyruvate carboxylase contributes to gluconeogenesis in liver cells.

Abstract

BACKGROUND:

Cystathionine 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.

METHODS:

Gene 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.

RESULTS:

Exogenously 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.

CONCLUSIONS:

CSE/H(2)S pathway plays an important role in the regulation of glucose production through S-sulfhydrating PC in the liver.

GENERAL SIGNIFICANCE:

Tissue-specific regulation of CSE/H(2)S pathway might be a promising therapeutic target of diabetes and other metabolic syndromes.

• Authors: YoungJun Ju, Ashley Untereiner, Lingyun Wu, Guangdong Yang
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1850 Issue 11 Pg. 2293-303 (Nov 2015) ISSN: 0006-3002 [Print] Netherlands
• PMID: 26272431 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical References

• Pyruvate Carboxylase
• Glucose
• Cysteine
• Hydrogen Sulfide

Topics

• Animals
• Cysteine (metabolism)
• Diet, High-Fat
• Gluconeogenesis
• Glucose (biosynthesis)
• HEK293 Cells
• Hep G2 Cells
• Humans
• Hydrogen Sulfide (pharmacology)
• Liver (metabolism)
• Male
• Mice
• Pyruvate Carboxylase (metabolism)