Oral berberine ameliorates high-fat diet-induced obesity by activating TAS2Rs in tuft and endocrine cells in the gut

Abstract

Background and aims: Although oral berberine, a natural compound extracted from the Chinese herbal medicine curcumin, has low bioavailability, it is still effective in suppressing obesity; however, the underlying mechanism is unclear. Berberine can bind to bitter-taste receptors (TAS2Rs) in intestinal endocrine secretin tumor (STC-1) cells to promote glucagon-like peptide-1 (GLP-1) secretion. Notably, TAS2Rs also exist in the tuft cells of the gut. Therefore, this study aimed to explore whether the beneficial effect of oral berberine on obesity is dependent on bitter-taste signaling in the tuft cells of the gut.

Methods and results: Standard chow diet (SCD) or high-fat diet (HFD) was administered to C57BL/6 mice, with or without berberine (100 mg/kg, 200 mg/kg, p. o.). The PLCβ2 inhibitor U73122 was used to verify whether the anti-obesity effect of berberine was dependent on the bitter-taste signaling pathway. In this study, we observed that the oral administration of berberine alleviated HFD-induced obesity in mice that U73122 partially inhibited. Both in vivo and ex vivo, berberine upregulated the release of GLP-1, promoted the proliferation of tuft cells and secretion of IL-25 in obesity via the TAS2R signaling pathway.

Conclusions: Oral berberine ameliorated HFD-induced obesity through the TAS2R-IL-25 signaling pathway in tuft cells in the gut.

Significance: We identified and functionally characterized the TAS2Rs and Gα-gustducin/Gβ1γ13 signaling pathway utilized by tuft cells in response to oral berberine in obese mice and proposed a new mechanism underlying the anti-obesity effect of berberine.

Keywords: Berberine; Bitter-taste receptor; Gut barrier; Obesity; Tuft cell.