Elevated copper impairs hepatic nuclear receptor function in Wilson’s disease
Clavia Ruth Wooton-Kee, … , Svetlana Lutsenko, David D. Moore
Clavia Ruth Wooton-Kee, … , Svetlana Lutsenko, David D. Moore
Published August 4, 2015
Citation Information: J Clin Invest. 2015;125(9):3449-3460. https://doi.org/10.1172/JCI78991.
View: Text | PDF
Research Article Hepatology

Elevated copper impairs hepatic nuclear receptor function in Wilson’s disease

Abstract

Wilson’s disease (WD) is an autosomal recessive disorder that results in accumulation of copper in the liver as a consequence of mutations in the gene encoding the copper-transporting P-type ATPase (ATP7B). WD is a chronic liver disorder, and individuals with the disease present with a variety of complications, including steatosis, cholestasis, cirrhosis, and liver failure. Similar to patients with WD, Atp7b–/– mice have markedly elevated levels of hepatic copper and liver pathology. Previous studies have demonstrated that replacement of zinc in the DNA-binding domain of the estrogen receptor (ER) with copper disrupts specific binding to DNA response elements. Here, we found decreased binding of the nuclear receptors FXR, RXR, HNF4α, and LRH-1 to promoter response elements and decreased mRNA expression of nuclear receptor target genes in Atp7b–/– mice, as well as in adult and pediatric WD patients. Excessive hepatic copper has been described in progressive familial cholestasis (PFIC), and we found that similar to individuals with WD, patients with PFIC2 or PFIC3 who have clinically elevated hepatic copper levels exhibit impaired nuclear receptor activity. Together, these data demonstrate that copper-mediated nuclear receptor dysfunction disrupts liver function in WD and potentially in other disorders associated with increased hepatic copper levels.

Authors

Clavia Ruth Wooton-Kee, Ajay K. Jain, Martin Wagner, Michael A. Grusak, Milton J. Finegold, Svetlana Lutsenko, David D. Moore

×

Figure 2

Nuclear receptor activity in Atp7b–/– mice.

Options: View larger image (or click on image) Download as PowerPoint
Nuclear receptor activity in Atp7b–/– mice. (A) Serum bile acid (BA) and...
(A) Serum bile acid (BA) and (B) bilirubin (BR) levels were measured in 3-month-old WT and Atp7b–/– mice. (C and G) Bsep, Mrp2, SHP, Cyp7a1, and Cyp8b1 mRNA expression levels were measured by real-time PCR for WT and Atp7b–/– mice at 2, 3, and 4–5 months of age. The Atp7b–/– target gene expression level is a percentage of that of the age-matched WT control. (D) Mice were given DMSO or 50 mg/kg BW GW4064 four hours prior to harvesting livers for analysis of Bsep and SHP mRNA levels. (E, F, and H–J) ChIP was performed using formaldehyde–cross-linked and purified nuclei and FXR, RXR, HNF4α, LRH-1, and RNA Pol II antibodies as indicated. The response elements on each promoter were amplified by real-time PCR and normalized to input. Primers for a gene desert region were used as a negative control (Neg). Error bars represent the mean ± SEM. *P < 0.05 by Student’s t test (A and B, n = 6–12 samples; E and F and H and I, n = 4 samples); *P < 0.05 by 1-way ANOVA, followed by Bonferroni’s post-hoc test (C and G, n = 4–6 samples); P < 0.05 by 2-way ANOVA, followed by Bonferroni’s post-hoc test (*WT versus KO GW4064 treatment, #WT versus KO vehicle, and **KO vehicle versus GW4064) (D, n = 4–6 samples).