Protein Adduction and Hepatotoxicity Induced by Stiripentol

Area of Science:

• Pharmacology
• Toxicology
• Biochemistry

Background:

• Stiripentol (STP) is an effective antiepileptic drug.
• The mechanism underlying STP-induced hepatotoxicity is not fully understood.

Purpose of the Study:

• To investigate the role of protein adduction in STP-induced hepatotoxicity.
• To elucidate the metabolic pathways leading to STP-derived reactive intermediates.

Main Methods:

• In vitro chemical reactions with STP and glutathione (GSH).
• Incubation of mouse liver cytosol with STP, GSH, and sulfation cofactors.
• Administration of STP to mice and primary hepatocytes, followed by analysis of protein adduction and liver enzymes.
• Inhibition studies using 2,6-dichloro-4-nitrophenol (SULT inhibitor) and L-buthionine-sulfoximine (GSH synthesis inhibitor).

Main Results:

• STP spontaneously forms a carbonium ion intermediate, leading to GSH conjugation.
• Sulfation by sulfotransferases (SULTs) accelerates the formation of this reactive intermediate.
• STP treatment in mice and hepatocytes resulted in significant protein adduction and elevated liver enzymes.
• Inhibitors of SULTs and GSH synthesis potentiated STP-induced protein adduction and cytotoxicity.

Conclusions:

• Protein adduction is a key mechanism responsible for Stiripentol-induced hepatotoxicity.
• Glutathione plays a crucial role in detoxifying STP-derived reactive metabolites, mitigating liver injury.