Changes in the mitochondrial proteome in human hepatocytes in response to alpha-amanitin hepatotoxicity

Area of Science:

• Hepatology
• Toxicology
• Mitochondrial Biology

Background:

• Alpha-amanitin (α-AMA) is implicated in liver damage pathogenesis via apoptosis.
• Limited research exists on α-AMA-induced proteome alterations, especially in mitochondria.

Purpose of the Study:

• To investigate mitochondrial proteome changes in hepatocytes exposed to α-AMA.
• To understand the toxic mechanism of α-AMA at the mitochondrial level.

Main Methods:

• Hepatocytes were treated with 2 μM α-AMA.
• Proteomic analysis identified differentially expressed mitochondrial proteins.
• Immunoblotting and immunofluorescence assessed protein levels and localization.
• Mitochondrial membrane potential was measured and tested for restoration by silibinin.

Main Results:

• 56 mitochondrial proteins were differentially expressed (38 downregulated, 18 upregulated) upon α-AMA treatment.
• Key downregulated proteins included TOMM40, cytochrome c, and malate dehydrogenase.
• α-AMA decreased mitochondrial TOMM40 and cytochrome c, increasing their cytosolic levels, and disrupted mitochondrial membrane potential.
• Silibinin restored the mitochondrial membrane potential, while mitochondrial morphology remained unchanged.

Conclusions:

• α-AMA induces significant mitochondrial proteome dysregulation and membrane potential loss in hepatocytes.
• These mitochondrial alterations contribute to α-AMA-induced liver toxicity.
• Silibinin shows potential in mitigating α-AMA's mitochondrial damage.