Oleanolic acid derivative HA-20 inhibits adipogenesis in a manner involving PPARγ-FABP4/aP2 pathway

Obesity is a chronic disease that increases the risk of type II diabetes, heart diseases and nonalcoholic fatty liver disease. Unfortunately, to date, only a handful of drugs are approved for clinical use. This study aims at the discovery of anti-obesity agents based on naturally sourced oleanolic acid (OA) derivatives. 3T3-L1 preadipocytes were differentiated into mature adipocytes for in vitro assays, and a high-fat diet (HFD)-induced obesity mice model was established for in vivo studies. The screening of the OA derivatives was performed with 3T3-L1 cell, and resulted in a discovery of a novel compound HA-20 with a potent inhibitory activity on 3T3-L1 adipogenesis. In vitro data demonstrated that HA-20 markedly suppressed the adipogenesis in 3T3-L1 at the early stage without cytotoxicity. In vivo research using HFD mice revealed that HA-20 lowered the body weight, and possessed a lipid-lowering effect. Transcriptome analysis discovered that the mainly adipogenesis/lipogenesis genes regulated by HA-20 were Pparg, Cebpa, Fas, Acc, and Fabp4/aP2. Mechanism study revealed that HA-20 played its bioactive roles at least via downregulating PPARγ-FABP4/aP2 pathway in 3T3-L1, which was further confirmed in HFD-induced obesity mice. Our findings provided a new insight into fighting fat accumulation based on OA derivatives, and demonstrated that HA-20 may sever as a worthy leading compound for the further development of anti-obesity agents.