Multi-Omics Analysis Reveals Sphingomyelin Accumulation, Glycerolipids Loss, and Disorders of Lipid Metabolism Regulated by Leucine Deprivation in the Liver of Mice

ScopeBranched-chain amino acids, especially leucine, have been reported to play a role in regulating lipid metabolism. This study aims to examine the effects of leucine deprivation on hepatic lipid metabolism.Methods and resultsC57BL/6 mice are fed with a chow diet (control group, n = 8) or a leucine-free diet (-Leu group, n = 8) for 7 days. Histology, lipidomics, targeted metabolomics, and transcriptomics are performed to analyze the liver tissue. Compared to control group, -Leu group exhibits a notably reduced liver weight, accompanied by hepatic injury, and disorders of lipid metabolism. The level of sphingomyelin (SM) is significantly increased in the liver of -Leu group, while the glycerolipids (GL) level is significantly decreased. The expression of sphingomyelin synthase 1 (SGMS1) is upregulated by leucine deprivation in a time-dependent manner, leading to hepatic SM accumulation. Moreover, leucine deprivation results in hepatic GL loss via suppressing fatty acid synthase (FASN) and acetyl-CoA carboxylase 1 (ACC1) expression.ConclusionThe findings demonstrate that leucine deprivation results in abnormal lipid metabolism in the liver, mainly manifested as SM accumulation and GL loss. These results provide insights into the role of leucine in regulating lipid metabolism. The investigation demonstrates that mice fed a leucine-free diet exhibits reduced liver weight, diminished lipid deposition capacity, alterations of hepatic lipid composition, and disorders of hepatic lipid metabolism. These findings provide insights into the relationship between leucine and lipid metabolism and offer a potential avenue for the nutritional modulation of amino acids.image