The liver plays a critical rule in metabolic homeostasis and drug clearance. Regretfully, hepatocytes, the parenchymal cells of the liver are in scarce supply, and their utilization is limited by high batch-to-batch variability. Human pluripotent stem cells (hPSC) are unlimited source of cells for drug development and clinical applications, having a limitless capacity for self-renewal and robust differentiation. However, hPSC-derived hepatocytes show limited mature function and fetal characteristics. Interestingly, hepatocytes develop mature mitochondrial features only during the postnatal period. The postnatal period is characterized by a shift from carbohydrate-rich placental to lipid-based enteral nutrition, suggesting that these nutritional cues may drive postnatal hepatic maturation.
In this work, we mimic the postnatal nutritional shift from glucose to lipid rich diet, by including breast milk-abundant fatty acids at the final stage of hPSC-derived and fetal hepatocyte differentiation. The addition of fatty acids induce the activity of hepatic nuclear receptors PPAR, PXR and LXR, which are essential for metabolic function of mature hepatocytes, by 1.5 to 6.5 folds. Our results show a PPAR-dependent increase in albumin and decrease in alpha-fetoprotein expression, characteristic of postnatal maturation. Functional and morphological analyses showed a PPAR-dependent increase in drug metabolism, as well as, mitochondrial function, biogenesis and fusion, recapitulating postnatal developmental processes. Metabolic analysis of the cells showed a 5-fold shift from glycolysis to oxidative phosphorylation indicative of mature function.
In conclusion, our work reveals that postnatal nutritional cues are tightly linked to fetal program shutdown and metabolic maturation, characteristic of postnatal hepatic-maturation offering a new source of cells for drug development and clinical application.
