Abstract
Endostatin is a well-known angiogenesis inhibitor. Although angiogenesis has been considered as a potential therapeutic target of obesity, the inhibitory effect of endostatin on adipogenesis and dietary-induced obesity has never been demonstrated. Adipogenesis plays a critical role in controlling adipocyte cell number, body weight, and metabolic profile in a homeostatic state. Here we reveal that endostatin inhibits adipogenesis and dietary-induced obesity. The antiadipogenic mechanism of endostatin lies in its interaction with Sam68 RNA-binding protein in the nuclei of preadipocytes. This interaction competitively impairs the binding of Sam68 to intron 5 of mammalian target of rapamycin (mTOR), causing an error in mTOR transcript. This consequently decreases the expression of mTOR, results in decreased activities of the mTOR complex 1 pathway, and leads to defects in adipogenesis. Moreover, our findings demonstrate that the antiangiogenic function of endostatin also contributes to its obesity-inhibitory activity. Through the combined functions on adipogenesis and angiogenesis, endostatin prevents dietary-induced obesity and its related metabolic disorders, including insulin resistance, glucose intolerance, and hepatic steatosis. Thus, our findings reveal that endostatin has a potential application for antiobesity therapy and the prevention of obesity-related metabolic syndromes.