A Gene Therapy Approach to Improve Copper Metabolism and Prevent Liver Damage in a Mouse Model of Wilson Disease.

Wilson disease (WD), an autosomal recessive disease caused by mutations in a copper-transporting P-type ATPase (Atp7b), causes severe liver damage. This disease is currently treated with the lifelong use of copper chelation therapy, which has side effects and does not fix copper metabolism. Here, we thoroughly characterized a mouse model of WD, the toxic milk (txJ) mouse, and used the model to test a gene therapy approach for treating WD. WD mice accumulated copper in the liver from birth; severe copper accumulation and concurrent liver disease were evident by two months of age. Intravenously administering an adeno-associated viral (AAV) 8 vector expressing a codon-optimized version of the human ATP7B transgene into two-month-old WD mice significantly decreased liver copper levels compared to age-matched, un-injected, WD mice. We also observed a significant dose-dependent decrease in liver disease. Male mice injected with 1011 genome copies of AAV8 vector showed only mild histopathological findings with a complete lack of liver fibrosis. Therefore, we conclude that administering gene therapy at the early stages of disease onset is a promising approach for reducing liver damage and correcting copper metabolism in WD.