Intestinal expression of metal transporters in Wilson's disease

In Wilson's disease (WND), biallelic ATP7B gene mutation is responsible for pathological copper accumulation in the liver, brain and other organs. It has been proposed that copper transporter 1 (CTR1) and the divalent metal transporter 1 (DMT1) translocate copper across the human intestinal epithelium, while Cu-ATPases: ATP7A and ATP7B serve as copper efflux pumps. In this study, we investigated the expression of CTR1, DMT1 and ATP7A in the intestines of both WND patients and healthy controls to examine whether any adaptive mechanisms to systemic copper overload function in the enterocytes. Duodenal biopsy samples were taken from 108 patients with Wilson's disease and from 90 controls. CTR1, DMT1, ATP7A and ATP7B expression was assessed by polymerase chain reaction and Western blot. Duodenal CTR1 mRNA and protein expression was decreased in WND patients in comparison to control subjects, while ATP7A mRNA and protein production was increased. The variable expression of copper transporters may serve as a defense mechanism against systemic copper overload resulting from functional impairment of ATP7B.