[Evaluation of Naturally Occurring Compounds Regulating Brown/Beige Adipocyte Differentiation]

Berberine stimulates fibroblast growth factor 21 by modulating the molecular clock component brain and muscle Arnt-like 1 in brown adipose tissue

Fibroblast growth factor 21 (FGF21), a member of the FGF subfamily that acts through the FGF receptor 1 with the co-receptor β-Klotho, functions as an important metabolic regulator of peripheral glucose tolerance and lipid homeostasis in an endocrine or autocrine and/or paracrine manner. Previous studies showed that FGF21 ameliorated and prevented the development of metabolic disorders, such as obesity and diabetes mellitus. In the present study, we demonstrated that berberine, a naturally occurring compound, stimulated FGF21 expression in brown adipose tissue (BAT). Furthermore, the up-regulated expression of FGF21 in brown adipocytes in response to berberine was due, at least in part, to the activation of the AMP-activated protein kinase pathway. We also found that berberine reversed high-fat diet-induced obesity concomitant with its regulation of the expression of Fgf21 and the core clock component brain and muscle Arnt-like 1 (Bmal1) in BAT. Berberine significantly up-regulated the gene expression and production of FGF21 in a dose-dependent manner in C3H10T1/2 brown adipocytes. Furthermore, the knockdown of Bmal1 prevented the up-regulated expression of FGF21 in response to berberine in C3H10T1/2 brown adipocytes, suggesting that Bmal1 links the regulatory mechanisms of FGF21 in response to berberine. The present results suggest that berberine stimulates the expression of FGF21 by modulating molecular clock Bmal1 in BAT, which may, in turn, attenuate diet-induced obesity. They also indicate the potential of berberine as a therapeutic agent for obesity and obesity-associated metabolic disorders related to circadian misalignments.