Actein ameliorates diet-induced obesity through the activation of AMPK-mediated white fat browning.

BACKGROUND

Targeting white adipose tissue (WAT) browning to increase systemic energy expenditure is a promising therapeutic strategy to combat obesity. Actein from Actaea cimicifuga L. has recently been reported to ameliorate high fat-induced hepatic steatosis. However, the effect of actein on diet-induced obesity merits more and further investigation.

PURPOSE

We aimed to examine the anti-obesity potential of actein and unravel its actions on WAT browning.

METHODS

The effect of actein on diet-induced obesity was evaluated using a high-fat diet model in C57BL/6 mice. Systemic energy expenditure of mice was measured with a combined indirect calorimetry system. Quantitative real-time PCR analyses were performed to investigate the mRNA levels of genes involved in thermogenesis, browning, and lipolysis. The protein levels were assessed by Western blot. Moreover, WAT explants and a transwell co-culture system consisting of SVFs and adipocytes were constructed to study the mechanisms of actein on promoting WAT browning and lipolysis.

RESULTS

At a dosage of 5 mg/kg/d, actein not only protected mice against diet-induced obesity and insulin resistance, but also reversed pre-established obesity and glucose intolerance in mice. Meanwhile, actein facilitated systemic energy expenditure by activating WAT lipolysis and browning. Further, mechanistic studies revealed that actein indirectly induced epididymal adipocyte lipolysis and directly promoted a white-to-beige conversion of subcutaneous adipocytes by activating the AMPK signaling.

CONCLUSION

Actein ameliorated diet-induced obesity and was discovered as a natural lead compound directly targeting white-to-beige conversion of subcutaneous adipocytes, suggesting the potential of developing new therapies for obesity and associated metabolic disorders.