Cover Story Current Issue

At the turn of the 19th century, Ivan Pavlov and others established that the secretion of pancreatic juice is induced upon entry of acidic chyme into the duodenum, and that this pancreatic secretion is accelerated by infusion of hydrochloric acid (HCL) into the stomach. Pavlov hypothesized that secretion of pancreatic juice is induced via a neuronal reflex; however, pancreatic secretion prevailed in dogs following denervation of the intestinal vagal and splanchnic nerves, indicating that pancreatic secretion must be mediated by another, as yet unknown, mechanism.

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Current Issue

Gut Microbiota Mediates SREBP-1c-Driven Hepatic Lipogenesis and Steatosis in Response to Zero-fat High-Sucrose Diet

Mattias Bergentall, Valentina Tremaroli, Chuqing Sun, Marcus Henricsson, ... Fredrik Bäckhed

 

Objective

Sucrose-rich diets promote hepatic de novo lipogenesis (DNL) and steatosis through interactions with the gut microbiota. However, the role of sugar-microbiota dynamics in the absence of dietary fat remains unclear. This study aimed to investigate the effects of a high-sucrose, zero-fat diet (ZFD) on hepatic steatosis and host metabolism in conventionally raised (CONVR) and germ-free (GF) mice.

Methods

CONVR and GF mice were fed a ZFD, and hepatic lipid accumulation, gene expression, and metabolite levels were analyzed. DNL activity was assessed by measuring malonyl-CoA levels, expression of key DNL enzymes, and activation of the transcription factor SREBP-1c. Metabolomic analyses of portal vein plasma identified microbiota-derived metabolites linked to hepatic steatosis. To further examine the role of SREBP-1c, its hepatic expression was knocked down using antisense oligonucleotides in CONVR ZFD-fed mice.

Results

The gut microbiota was essential for sucrose-induced DNL and hepatic steatosis. In CONVR ZFD-fed mice, hepatic fat accumulation increased alongside elevated expression of genes encoding DNL enzymes, higher malonyl-CoA levels, and upregulation of SREBP-1c. Regardless of microbiota status, ZFD induced fatty acid elongase and desaturase gene expression and increased hepatic monounsaturated fatty acids. Metabolomic analyses identified microbiota-derived metabolites associated with hepatic steatosis. SREBP-1c knockdown in CONVR ZFD-fed mice reduced hepatic steatosis and suppressed fatty acid synthase expression.

Conclusion

Sucrose-microbiota interactions and SREBP-1c are required for DNL and hepatic steatosis in the absence of dietary fat. These findings provide new insights into the complex interplay between diet, gut microbiota, and metabolic regulation.

 

Articles in Press

Gut Microbiota Mediates SREBP-1c-Driven Hepatic Lipogenesis and Steatosis in Response to Zero-fat High-Sucrose Diet

Mattias Bergentall, Valentina Tremaroli, Chuqing Sun, Marcus Henricsson, ... Fredrik Bäckhed

 

Objective

Sucrose-rich diets promote hepatic de novo lipogenesis (DNL) and steatosis through interactions with the gut microbiota. However, the role of sugar-microbiota dynamics in the absence of dietary fat remains unclear. This study aimed to investigate the effects of a high-sucrose, zero-fat diet (ZFD) on hepatic steatosis and host metabolism in conventionally raised (CONVR) and germ-free (GF) mice.

Methods

CONVR and GF mice were fed a ZFD, and hepatic lipid accumulation, gene expression, and metabolite levels were analyzed. DNL activity was assessed by measuring malonyl-CoA levels, expression of key DNL enzymes, and activation of the transcription factor SREBP-1c. Metabolomic analyses of portal vein plasma identified microbiota-derived metabolites linked to hepatic steatosis. To further examine the role of SREBP-1c, its hepatic expression was knocked down using antisense oligonucleotides in CONVR ZFD-fed mice.

Results

The gut microbiota was essential for sucrose-induced DNL and hepatic steatosis. In CONVR ZFD-fed mice, hepatic fat accumulation increased alongside elevated expression of genes encoding DNL enzymes, higher malonyl-CoA levels, and upregulation of SREBP-1c. Regardless of microbiota status, ZFD induced fatty acid elongase and desaturase gene expression and increased hepatic monounsaturated fatty acids. Metabolomic analyses identified microbiota-derived metabolites associated with hepatic steatosis. SREBP-1c knockdown in CONVR ZFD-fed mice reduced hepatic steatosis and suppressed fatty acid synthase expression.

Conclusion

Sucrose-microbiota interactions and SREBP-1c are required for DNL and hepatic steatosis in the absence of dietary fat. These findings provide new insights into the complex interplay between diet, gut microbiota, and metabolic regulation.

 

Save the Date

12th Helmholtz 
Diabetes Conference 
22-24. Sep, Munich

You are what you eat

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