The TFEB activator clomiphene citrate ameliorates lipid metabolic syndrome pathology by activating lipophagy and lipolysis.

Abstract

The balance between lipid synthesis and lipid catabolism is critical to maintain energy homeostasis. Lipophagy and lipolysis are two important pathways for lipid selective catabolism. Defects in lipophagy and lipolysis are linked to lipid metabolic diseases. Transcription factor EB (TFEB) is a master regulator of autophagy and lysosome biogenesis, as well as lipid metabolism by promoting expression of genes encoding fat catabolic lipases. Therefore, targeting TFEB provides a novel potential strategy for the treatment of lipid metabolic diseases. In this study, we showed that the TFEB activator clomiphene citrate (CC) activated the autophagy-lysosome and lipolysis pathways, and promoted degradation of lipid droplets induced by the free fatty acids oleate and palmitate in HepG2 cells. Moreover, CC treatment promoted lipid catabolism and attenuated obesity, restored lipid levels, blood glucose levels and insulin resistance, hepatocellular injury and hepatic steatosis, as well as liver inflammation in the HFD fed mice. In addition, we found that En-CC, a trans-isomer of CC, displayed less toxicity and more efficient activation of TFEB. Consistent with CC, En-CC treatment improved lipid metabolic syndrome pathology. These findings demonstrate that CC promotes clearance of lipids and ameliorates HFD-induced lipid metabolic syndrome pathology through activating TFEB-mediated lipophagy and lipolysis, indicating that CC has the potential to be used to treat lipid metabolic diseases.