Methanobactin reverses acute liver failure in a rat model of Wilson disease
Josef Lichtmannegger, … , Karl Heinz Weiss, Hans Zischka
Josef Lichtmannegger, … , Karl Heinz Weiss, Hans Zischka
Published June 20, 2016
Citation Information: J Clin Invest. 2016;126(7):2721-2735. https://doi.org/10.1172/JCI85226.
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Research Article Gastroenterology Hepatology

Methanobactin reverses acute liver failure in a rat model of Wilson disease

Abstract

In Wilson disease (WD), functional loss of ATPase copper-transporting β (ATP7B) impairs biliary copper excretion, leading to excessive copper accumulation in the liver and fulminant hepatitis. Current US Food and Drug Administration– and European Medicines Agency–approved pharmacological treatments usually fail to restore copper homeostasis in patients with WD who have progressed to acute liver failure, leaving liver transplantation as the only viable treatment option. Here, we investigated the therapeutic utility of methanobactin (MB), a peptide produced by Methylosinus trichosporium OB3b, which has an exceptionally high affinity for copper. We demonstrated that ATP7B-deficient rats recapitulate WD-associated phenotypes, including hepatic copper accumulation, liver damage, and mitochondrial impairment. Short-term treatment of these rats with MB efficiently reversed mitochondrial impairment and liver damage in the acute stages of liver copper accumulation compared with that seen in untreated ATP7B-deficient rats. This beneficial effect was associated with depletion of copper from hepatocyte mitochondria. Moreover, MB treatment prevented hepatocyte death, subsequent liver failure, and death in the rodent model. These results suggest that MB has potential as a therapeutic agent for the treatment of acute WD.

Authors

Josef Lichtmannegger, Christin Leitzinger, Ralf Wimmer, Sabine Schmitt, Sabine Schulz, Yaschar Kabiri, Carola Eberhagen, Tamara Rieder, Dirk Janik, Frauke Neff, Beate K. Straub, Peter Schirmacher, Alan A. DiSpirito, Nathan Bandow, Bipin S. Baral, Andrew Flatley, Elisabeth Kremmer, Gerald Denk, Florian P. Reiter, Simon Hohenester, Friedericke Eckardt-Schupp, Norbert A. Dencher, Jerzy Adamski, Vanessa Sauer, Christoph Niemietz, Hartmut H.J. Schmidt, Uta Merle, Daniel Nils Gotthardt, Guido Kroemer, Karl Heinz Weiss, Hans Zischka

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Figure 2

Increasing copper load severely attacks mitochondrial membrane integrity.

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Increasing copper load severely attacks mitochondrial membrane integrity...
(A) Progressive disease in Atp7b–/– rats was paralleled by a decrease in normally structured mitochondria (Type 1 and Type 2) and an increase in structurally altered mitochondria (Type 3 and Type 4). Scale bars: 500 nm. Control Atp7b+/– rats (aged 82–89 days): N = 3, n = 561; affected Atp7b–/– rats (aged 92–93 days): N = 3, n = 372; disease-onset Atp7b–/– rats (aged 83–93 days): N = 3, n = 575; diseased Atp7b–/– rats (aged 104–107 days): N = 5, n = 857. (B) Upon calcium- or copper-induced MPT, isolated Atp7b+/– mitochondria underwent large-amplitude swelling, which was significantly reduced in Atp7b–/– mitochondria from diseased and disease-onset rats. Control Atp7b+/– rats: N = 3, n = 6; affected Atp7b–/– rats: N = 3, n = 6; disease-onset Atp7b–/– rats: N = 2, n = 4; diseased Atp7b–/– rats: N = 3, n = 6. (C) Calcium-induced (100 μM) MPT could be efficiently inhibited by Cys-A (5 μM). This blocking effect was severely impaired in mitochondria from diseased and disease-onset Atp7b–/– rats. A representative comparative MPT measurement of mitochondria isolated from an Atp7b+/– control rat and from Atp7b–/– animals at different disease stages is depicted (quantitative analysis is shown in Supplemental Table 2). (D) Atp7b–/– mitochondria lost their membrane potential (ΔΨ) at earlier time points than did control mitochondria. A representative comparative ΔΨ measurement of mitochondria isolated from an Atp7b+/– control and Atp7b–/– animals at different disease stages is depicted (quantitative analysis is shown in Supplemental Table 3). Data in A and B were outlier corrected. P values were determined by 1-way ANOVA with Tukey’s multiple comparisons test. (A) *P < 0.05, **P < 0.01, and ***P < 0.001 versus control. (B) **P < 0.01 and ****P < 0.0001 versus control; #P < 0.05, ##P < 0.01, and ####P < 0.0001 versus affected; ††P < 0.01 versus disease onset. N = number of rats, n = number of analyzed mitochondria. FCCP, carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone.