The liver proteome of individuals with a natural UGT2B17 complete deficiency

Glucuronidation is a crucial pathway for the metabolism and detoxification of drugs and endobiotics, and primarily occurs in the liver. UGT2B17 is one of the 22 glycosyltransferases (UGT) that catalyze this reaction. In a large proportion of the population, UGT2B17 is absent due to complete gene deletion. We hypothesized that a UGT2B17 human deficiency affects the composition and function of the liver proteome, potentially provoking compensatory responses, and altering interconnected pathways and regulatory networks. The objective was to elucidate the liver proteome of UGT2B17-deficient individuals. Liver specimens from UGT2B17-deficient and proficient individuals were compared by mass spectrometry-based proteomics using data-independent acquisition. In UGT2B17-deficient livers, 80% of altered proteins showed increased abundance with a notable enrichment in various metabolic and chemical defense pathways, cellular stress and immune-related responses. Enzymes involved in the homeostasis of steroids, nicotinamide, carbohydrate and energy metabolism, and sugar pathways were also more abundant. Some of these changes support compensatory mechanisms, but do not involve other UGTs. An increased abundance of non-metabolic proteins suggests an adaptation to endoplasmic reticulum stress, and activation of immune responses. Data implies a disrupted hepatocellular homeostasis in UGT2B17-deficient individuals and offers new perspectives on functions and phenotypes associated with a complete UGT2B17 deficiency.