Metabolomics analysis revealed distinct cyclic changes of metabolites altered by chronic ethanol-plus-binge and Shp-deficiency

Abstract

Background Chronic ethanol consumption causes alcoholic liver disease (ALD) and disruption of the circadian system facilitates the development of ALD. Small heterodimer partner (SHP) is a nuclear receptor and critical regulator of hepatic lipid metabolism. This study aims at depicting circadian metabolomes altered by chronic ethanol-plus-binge and Shp-deficiency using high throughput Metabolomics. Methods Wild-type (WT) C57Bl/6 and Shp-/- mice were fed the control diet (CD) or Lieber De-Carli ethanol liquid diet (ED) for 10 days followed by a single bout of maltose (CD+M) or ethanol (ED+E) binge on the 11th day. Serum and liver were collected over a 24 hr light-dark (LD) cycle at Zeitgeber time ZT12, ZT18, ZT0 and ZT6 and metabolomics was performed using GC-MS. Results A total of 110 metabolites were identified in liver and of those 80 were also present in serum from pathways of carbohydrates, lipids, pentose phosphate, amino acids, nucleotides and tricarboxylic acid (TCA) cycle. In the liver, 91% of metabolites displayed rhythmicity with ED+E whereas in the serum, only 87% were rhythmic. Bioinformatics analysis identified unique metabolome patterns altered in WT CD+M, WT ED+E, Shp-/- CD+M, and Shp-/- ED+E groups. Specifically, metabolites from the nucleotide and amino acid pathway (ribose, glucose-6-phosphate, glutamic acid, aspartic acid and seduheptulose-7-P) were elevated in Shp-/- CD+M mice during the dark cycle, whereas metabolites including N-methylalanine, 2-hydroxybutyric acid, 2-hydroxyglutarate were elevated in WT ED+E mice during the light cycle. The rhythmicity and abundance of other individual metabolites were also significantly altered by both control and ethanol diets. Conclusions Metabolomics provides a useful means to identify unique metabolites altered by chronic ethanol-plus-binge.