Amr Ali1, Yanjie Zhang2, Ming Fu3, Yanxi Pei4, Lingyun Wu3, Rui Wang5, Guangdong Yang6. 1. Department of Chemistry and Biochemistry, Canada; Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada. 2. Department of Chemistry and Biochemistry, Canada; Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada; School of Life Science, Shanxi University, Taiyuan, China. 3. Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada; School of Human Kinetics, Laurentian University, Sudbury, Canada; Health Science North Research Institute, Sudbury, Canada. 4. School of Life Science, Shanxi University, Taiyuan, China. 5. Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada. 6. Department of Chemistry and Biochemistry, Canada; Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada. Electronic address: gyang2@laurentian.ca.
Abstract
AIMS: Hydrogen sulfide (H2S) as a novel gasotransmitter can be endogenously produced in liver by cystathionine gamma-lyase (CSE). The dysfunctions of CSE/H2S system have been linked to various liver diseases. Acetyl-CoA is the key intermediate from the metabolism of lipid. This study examined the roles of H2S in hepatic acetyl-CoA and lipid metabolism. MATERIALS AND METHODS: Both in vitro cell model and in vivo animal model of lipid accumulation were used in this study. Western blotting and real-time PCR were used for analysis of protein and mRNA expression. Acetyl-CoA was analyzed by a coupled enzyme assay, and lipid accumulation was observed with Oil Red O staining. KEY FINDINGS: Incubation of human liver carcinoma (HepG2) cells with a mixture of free fatty acids (FFAs) or high glucose reduced CSE expression and H2S production, promoted intracellular accumulation of acetyl-CoA and lipid. Supply of exogenous NaHS or cysteine reduced acetyl-CoA contents and lipid accumulation, while blockage of CSE activity promoted intracellular lipid accumulation. Furthermore, H2S blocked FFAs-induced transcriptions of de novo lipogenesis, inflammation, and fibrosis-related genes. In vivo, knockout of CSE gene stimulated more hepatic acetyl-CoA and lipid accumulation in mice induced by high-fat choline-deficient diet. The expressions of lipogenesis, inflammation, and fibrosis-related genes were significantly higher in liver tissues from CSE knockout mice when compared with wild-type mice. SIGNIFICANCE: CSE/H2S system is indispensable for maintaining the homeostasis of acetyl-CoA and lipid accumulation and protecting from the development of inflammation and fibrosis in liver under excessive caloric ingestion.
AIMS: Hydrogen sulfide (H2S) as a novel gasotransmitter can be endogenously produced in liver by cystathionine gamma-lyase (CSE). The dysfunctions of CSE/H2S system have been linked to various liver diseases. Acetyl-CoA is the key intermediate from the metabolism of lipid. This study examined the roles of H2S in hepatic acetyl-CoA and lipid metabolism. MATERIALS AND METHODS: Both in vitro cell model and in vivo animal model of lipid accumulation were used in this study. Western blotting and real-time PCR were used for analysis of protein and mRNA expression. Acetyl-CoA was analyzed by a coupled enzyme assay, and lipid accumulation was observed with Oil Red O staining. KEY FINDINGS: Incubation of humanliver carcinoma (HepG2) cells with a mixture of free fatty acids (FFAs) or high glucose reduced CSE expression and H2S production, promoted intracellular accumulation of acetyl-CoA and lipid. Supply of exogenous NaHS or cysteine reduced acetyl-CoA contents and lipid accumulation, while blockage of CSE activity promoted intracellular lipid accumulation. Furthermore, H2S blocked FFAs-induced transcriptions of de novo lipogenesis, inflammation, and fibrosis-related genes. In vivo, knockout of CSE gene stimulated more hepatic acetyl-CoA and lipid accumulation in mice induced by high-fat choline-deficient diet. The expressions of lipogenesis, inflammation, and fibrosis-related genes were significantly higher in liver tissues from CSE knockout mice when compared with wild-type mice. SIGNIFICANCE: CSE/H2S system is indispensable for maintaining the homeostasis of acetyl-CoA and lipid accumulation and protecting from the development of inflammation and fibrosis in liver under excessive caloric ingestion.
Authors: Courtney D McGinnis; Erin Q Jennings; Peter S Harris; James J Galligan; Kristofer S Fritz Journal: Cells Date: 2022-06-28 Impact factor: 7.666