PROJECT SUMMARY The mortality rate of liver disease due to alcohol abuse, is steadily increasing, necessitating early clinical intervention. Current intervention techniques, such as resection and transplantation, rely extensively on the liver's ability to regenerate. During the normal regenerative course, hepatocytes must not only proliferate but also metabolically compensate for lost tissue mass. However, during ALD progression, this proliferative ability is significantly diminished. There are additional detriments at the metabolic level, as zonation, or the spatial organization of metabolic processes across the liver lobule, becomes dysregulated with many key gluconeogenic and lipid metabolizing enzymes losing their spatial specificity. To date, little is known about the specific metabolic events allowing for hepatocellular proliferation during regeneration, and how metabolic reprogramming leads to diminished proliferation in ALD. Therefore, the goals of this project are to uncover the metabolic mechanisms driving heterogeneous, zonated hepatocyte populations to tissue mass restoration and to elucidate the metabolic reprogramming events impairing proper regeneration during ALD progression. Through this work, we aim to test two hypotheses: (1) during regeneration, at peak cellular proliferation, normally zonated metabolic gene expression is disrupted, leading to a reduction in metabolically compensating hepatocytes and a decrease in overall proliferative ability in ethanol-adapted livers; (2) there exists a set of pathological, zone-specific metabolic reprogramming events that can signify the extent of alcohol-associated, decompensated liver damage and hepatocyte proliferative ability at each stage of progressing ALD. The first hypothesis seeks to determine the relationship between spatial regulation and metabolic functionality of distinct hepatocyte populations during regeneration. This hypothesis will be tested using a chronic ethanol-fed rat model of partial hepatectomy, in which 70% of the liver is resected, to identify the relationship between metabolic gene transcription and function of heterogeneous hepatocyte populations, proliferating and metabolically compensating, during regeneration. The second hypothesis seeks to identify the metabolic reprogramming events occurring during progressive ALD in human patients. Extensive analyses of metabolomic and transcriptomic data from human tissue samples with progressing ALD will be performed to test this hypothesis. Both hypotheses will employ quantitative metabolic modelling approaches to make functional predictions about the enzymatic behavior of hepatocytes during health and disease, which will be compared to and tested against collected metabolomics data. Through this work, we seek to elucidate the mechanisms disrupting the tightly interconnected relationship between metabolic regulation and function during alcohol adaptation, and determine the metabolic reprogramming events occurring at ea...