Comparative hepatic transcriptome analyses revealed possible pathogenic mechanisms of fasiglifam (TAK-875)-induced acute liver injury in mice

Fasiglifam (TAK-875), a G protein-coupled receptor 40 (GPR40) agonist, was a drug candidate for type 2 diabetes. However, its development was terminated in phase 3 trials due to liver safety concerns. Although TAK-875 was reported to inhibit hepatobiliary transporters and disturb bile acid disposition, pathogenic mechanisms of TAK-875-induced liver injury are not fully understood. In this study, we sought to identify the mechanisms with a hepatic genome-wide transcriptomic analysis in a murine model. We demonstrated that, among the three GPR40 agonists, TAK-875, AMG-837 and TUG-770, only TAK-875 induced acute liver injury in mice. Transcriptome profiles of TAK-875-exposed liver was compared with those of non-hepatotoxic analogues AMG-837 and TUG-770 as negative controls and those of classical hepatotoxicants concanavalin A and carbon tetrachloride as positive controls. The comparative hepatic transcriptome analyses revealed the enrichment of genes involved in inflammation, endoplasmic reticulum (ER) stress, apoptosis, and hepatic lipid accumulation, suggesting that these events play pathophysiologic roles in the development of TAK-875-induced liver injury. These results were validated by quantitative PCR with significant changes in chemokines, danger signals, ER stress mediators, proapoptotic factors, and hepatic steatosis markers only in TAK-875-exposed liver. Pretreatment of TAK-875-administered mice with an ER stress inhibitor 4-phenylbutyric acid (4-PBA) alleviated the liver injury. Consistent with the in vivo study, pretreatment of HepG2 cells with 4-PBA significantly improved the decrease of cell viability induced by TAK-875. In conclusion, by a comprehensive transcriptomic analysis of GPR40 agonists, we found multiple possible processes that contribute to TAK-875-induced acute liver injury in mice. Liver samples were collected 24 hours after administration of each GPR40 agonist and vehicle. Total RNA was extracted from these liver samples and equal amount of RNA was pooled from 4 animals in each group.