Hepatic lipid metabolism is altered in Ubiad1+/− mice of both sexes

UbiA prenyltransferase domain containing 1 (Ubiad1) has the potential to affect cholesterol and phospholipid levels in different cell types. We previously identified Ubiad1 as a candidate gene for regulating subcutaneous fat pad weight in a mouse genome-wide association study. Here we evaluated the relationship between Ubiad1 and obesity-related traits in cohorts of humans and mice, and in Ubiad1^+/- mice fed a high-fat diet. In both humans and mice, adipose tissue Ubiad1 mRNA expression correlated negatively with adiposity and positively with mitochondria-related genes. To determine the role of Ubiad1 in high-fat diet-induced obesity, we disrupted the Ubiad1 gene in mice. Deletion of Ubiad1 was embryonically lethal in C57BL/6 N mice, preventing analysis of adult Ubiad1^-/- mice. Thus, male and female Ubiad1^+/+ and Ubiad1^+/- mice were fed high-fat diet for 10 weeks, with no difference in weight gain and adipose tissue organ weights observed between the genotypes. Analysis of liver mRNA expression revealed that Ubiad1 heterozygosis (Ubiad1^+/-) altered several pathways involved in lipid metabolism. Detailed lipid quantification with HPLC-qTOF/MS showed increased levels of hepatic ceramides in female Ubiad1^+/- mice, whereas phosphatidylglycerols, phosohatidylinositol and lysophosphatidylethanolamines were reduced in male Ubiad1^+/- mice. Our findings reveal sex-specific effects of Ubiad1 expression on hepatic lipid metabolism.