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[Copper-binding proteins in liver, kidney and brain tissue from a Wilson's disease patient]
Insights
Wilson's disease significantly increases copper-binding proteins (Cu-PBs) in liver and kidney tissues, primarily as copper-thionein (Cu-Th). Brain tissue shows elevated copper bound to novel proteins, indicating altered copper metabolism in Wilson's disease.
Area of Science:
- Biochemistry
- Molecular Biology
- Pathology
Context:
- Wilson's disease is a genetic disorder characterized by excessive copper accumulation in organs.
- Copper toxicity profoundly affects liver, kidney, and brain function.
- Understanding copper-binding proteins is crucial for diagnosing and treating Wilson's disease.
Purpose:
- To investigate the distribution and forms of copper-binding proteins (Cu-PBs) in Wilson's disease patient tissues.
- To quantify copper levels and identify specific Cu-PBs in liver, kidney, and brain.
- To compare these findings with control tissues to elucidate disease-specific alterations.
Summary:
- Copper levels were significantly elevated in the liver (28-fold), kidney (38-fold), and brain (3.5-fold) of a Wilson's disease patient compared to controls.
- In Wilson's disease liver and kidney cytosols, increased copper was predominantly bound to copper-thionein (Cu-Th).
- Wilson's disease brain cytosol showed elevated copper bound to two novel proteins (10 kDa and 20 kDa), distinct from control brain tissue.
Impact:
- This study identifies specific copper-binding protein alterations in Wilson's disease, offering insights into disease mechanisms.
- The findings highlight the differential roles of Cu-Th and novel proteins in copper dyshomeostasis.
- Characterizing these proteins may lead to improved diagnostic markers and therapeutic targets for Wilson's disease.
Abstract:
Copper-binding proteins (Cu-PBs) in the liver, kidney, and brain tissues from a Wilson's disease patient, who was 19-year-old woman and died of hemolytic crisis, were examined with Sephadex G-75 gel chromatography and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Copper contents, which were determined by flameless atomic absorption spectrophotometry in the liver, kidney, and cerebral tissues from the patient, were 28-, 38-, and 3.5-fold, respectively, as compared to those of control subject, who was 5-year-old girl and died of cerebral palsy. Each tissue was homogenized in 3 volumes of 50 mM Tris-HCl buffer, pH 8.6, and the homogenate was centrifuged at 105,000 g for 60 min to obtain cytosol fraction. Sephadex G-75 gel chromatography of cytosols from Wilson's liver and kidney showed that most of increased copper existed as Cu-thionein (Cu-Th), in contrast to a much lower Cu-Th level in control liver cytosol and to no detectable amount of Cu-Th in control kidney cytosol. In addition, Zn-Th was also increased in Wilson's kidney cytosol, while it was decreased in Wilson's liver cytosol. Gel chromatography of Wilson's cerebral cytosol revealed that the increased copper bound mainly to two proteins with apparent molecular mass of 10 kDa (Cu-BP 1) and 20 kDa (Cu-BP 2), respectively, both of which showed no absorption at 280 nm and were not observed in control cerebral cytosol even after addition of excess copper (50 micrograms/ml) as CuSO4.(ABSTRACT TRUNCATED AT 250 WORDS)