Nuclear Receptor Dysfunction Reprograms Metabolism and Cellular Proliferation in Wilson's Disease

PROJECT SUMMARY Wilson’s disease is an autosomal recessive disorder caused by mutations in the copper-transporting P- type ATPase, ATP7b, resulting in excessive copper accumulation primarily in the liver and brain. Elevation of free copper leads to oxidative stress and mitochondrial dysfunction, inflammation, steatosis, fibrosis, and cirrhosis. Treatments for Wilson’s disease are limited to chelation or zinc therapies and often associated with many side effects. Atp7b-/- mice exhibit hallmarks of the progressive liver pathology present in Wilson’s disease patients. By using specific nuclear receptors expressed in the liver and intestine, we will address transcriptomic and metabolomic changes to understand how copper reprograms the metabolic and cellular signaling pathways in the liver of Atp7b-/- mice. The lack of well-defined molecular mechanisms for therapeutic targeting represents a critical gap in our scientific understanding of liver disease. Our preliminary data in Atp7b-/- mice revealed decreased metabolic nuclear receptor activity and target gene expression that dynamic changes in hepatic metabolic composition. We also discovered that hepatic nodule formation in older Atp7b-/- mice is exacerbated by deletion of PXR in Atp7b-/- mice. These findings suggest that reprogrammed metabolism and cell cycle regulation contribute to the hepatic phenotype of Atp7b-/- mice, and overlap other chronic hepatic disorders. Rationale: definition of molecular targets of Cu++ toxicity will provide novel therapeutic targets for WD treatment. Our proposed studies will test the central hypothesis: Cu++-compromises PXR activities and promotes liver dysfunction in Wilson’s disease.