Oxysterol misbalance critically contributes to Wilson disease pathogenesis

Area of Science:

• Biochemistry and Molecular Biology
• Hepatology and Metabolic Disorders

Background:

• Wilson disease (WD) is a genetic metabolic disorder characterized by copper overload due to ATP7B dysfunction.
• Excess copper induces oxidative stress and liver pathology through mechanisms not fully understood.

Purpose of the Study:

• To elucidate the mechanistic connections between copper overload and liver pathology in Wilson disease.
• To identify key molecular pathways driving advanced hepatic WD and explore potential therapeutic interventions.

Main Methods:

• Utilized a mouse model of Wilson disease (Atp7b mice) with established liver disease.
• Investigated the role of the transcription factor Nrf2 and its target Sult1e1 in copper-induced liver damage.
• Assessed the impact of Sult1e1 inhibition and LXR agonist treatment on sterol balance, inflammation, and fibrosis.

Main Results:

• Copper overload activated Nrf2, leading to increased Sult1e1 expression, altered sterol metabolism (elevated sulfated sterols, decreased oxysterols), and LXR inhibition.
• Pharmacological Sult1e1 inhibition partially corrected sterol imbalance and LXR activity.
• LXR agonist treatment in WD mice reduced inflammation, diminished fibrosis via TGF-β pathway modulation, and improved liver function and morphology.

Conclusions:

• The Nrf2-Sult1e1-mediated sterol misbalance and subsequent LXR inhibition represent a critical pathway driving advanced hepatic Wilson disease.
• Targeting this pathway, particularly with LXR agonists, shows therapeutic potential for managing liver inflammation and fibrosis in WD.