Toxicoproteomics reveals an effect of clozapine on autophagy in human liver spheroids

Background: Clozapine is an atypical antipsychotic drug used to treat treatment-resistant schizophrenia. Its side effects, including liver enzyme abnormalities, experienced by many patients preclude its more common use as a first-line therapy for schizophrenia. Toxicoproteomic approaches have been demonstrated to effectively guide the identification of toxicological mechanisms. Methods: To further our understanding of the molecular effects of clozapine, we performed a data-independent acquisition (DIA)-based quantitative proteomics investigation of clozapine-treated human liver spheroid cultures. Results: In total, we quantified 4479 proteins across the five treatment groups (vehicle; 15 µM, 30 µM, and 60 µM clozapine; and 10 ng/mL TNFα + IL-1β). Clozapine (60 µM) treatment yielded 36 differentially expressed proteins (FDR Conclusions: Combined with prior literature, our work suggests a broad contribution of autophagy to both the therapeutic and side effects of clozapine. Overall, this study demonstrates how proteomics can contribute to the elucidation of physiological and toxicological mechanisms of drugs.