Cytotoxicity and Toxicoproteomic Analysis of Pioglitazone Exposure in Human-derived Cardiomyocytes

Abstract Pioglitazone (PGZ) is a peroxisome proliferator-activated receptor gamma agonist widely used as an insulin sensitiser agent for type II diabetes mellitus. The heterogeneity of PGZ effects on cardiac tissue has remained controversial, as contradictory data exist in the literature. Nevertheless, a consensus has reported an associated increased risk of heart failure (HF) following chronic systemic exposure to PGZ, which has hampered its clinical use in diabetes management. The mechanism of PGZ-induced HF remains largely uncharacterised. Here, we report a comprehensive in vitro study combining a novel toxico-proteomic pipeline with cytotoxicity assays in human adult cardiomyocytes to elucidate mechanistic insights into PGZ cardiotoxicity and identify driver proteins associated with such effects. Cytotoxicity assay findings showed a significant loss of mitochondrial adenosine triphosphate production following PGZ exposure, suggesting that this decline underpins PGZ cardiotoxicity. Interestingly, proteomics analysis revealed that the mitochondrial dysfunction was attributed to PGZ mediating mitochondrial uncoupling and ultimately cardiomyocyte death. The type of cell death was also found to be related to the mitochondria—protein upregulation in the phosphoglycerate mutase family 5–dynamin-related protein 1 axis, suggesting mitochondrial-mediated necroptosis. Furthermore, our analysis suggested the potential activation of the interplay between the complement and coagulation systems and the disruption of the cytoskeletal architecture, which was primarily mediated through integrin-signalling pathways, responsible for PGZ-induced myocardial contractile failure. Collectively, our findings provide substantial mechanistic insight into PGZ adverse effects and may eventually provide the rationale for future optimisation of antidiabetic therapies. (239 words)