Suppression of Adipogenesis and Fat Accumulation by Vitexin Through Activation of Hedgehog Signaling in 3T3-L1 Adipocytes.

Many studies have demonstrated that adipogenesis is associated with obesity, and the Hedgehog (Hh) signaling pathway regulates adipogenesis and obesity. Following the screening study of the chemical library evaluating the effect of vitexin on Gli1 transcriptional activity, vitexin was chosen as a candidate for antiadipogenic efficacy. Vitexin significantly reduced lipid accumulation and suppressed C/EBPα (CCAAT/enhancer-binding protein α) and PPARγ (peroxisome proliferator-activated receptor γ) expression, which are known as key adipogenic factors in the early stages of adipogenesis by activating Hh signaling. Furthermore, Hh inhibitor GANT61 reversed the effect of AMP-activated protein kinase (AMPK) activator AICAR (5-aminoimidazole-4-carboxamide ribonucleotide), indicating that Hh signaling is an upstream regulator of AMPK in 3T3-L1 cells. Vitexin suppressed adipogenesis by regulating Hh signaling and phosphorylation of AMPK, leading to the inhibition of fat formation. These results suggest that vitexin can be considered a potent dietary agent in alleviating lipid accumulation and obesity.

Caudatin suppresses adipogenesis in 3T3-L1 adipocytes and reduces body weight gain in high-fat diet-fed mice through activation of hedgehog signaling.

BACKGROUND: The regulative effects of caudatin, a C-21 steroid that is identified from Cynanchum bungee roots, on adipogenesis and obesity have not been studied. Many studies have demonstrated that the activation of hedgehog (Hh) signaling can help prevent obesity. Therefore, we hypothesized that caudatin can inhibit adipogenesis and obesity via activating the Hh signaling pathway. METHODS: To investigate the effects of caudatin on adipogenesis in 3T3-L1 preadipocytes and high-fat diet induced obesity in C57BL/6 mice, in vitro and in vivo experiments were performed. For in vitro evaluation, Oil red O staining were used to represent lipid accumulation in differentiated 3T3-L1 adipocytes. For in vivo assessment, male 5 week-old C57BL/6 mice were fed with standard chow diet, high-fat diet (HFD), HFD with 25 mg/kg caudatin, HFD with 1mg/kg purmorpharmine for 10 weeks, respectively. Hh signaling and key adipogenic marker involved in adipogenesis were evaluated by real-time PCR and western blot. The adipocyte size of white adopose tissue and lipid storage of liver were visualized by hematoxylin and eosin staining. In addition, the expression of Gli1 and peroxisome proliferator-activated receptor γ (PPARγ) in white adipose tissue were investigated by immunohistochemistry staining. RESULTS: Caudatin suppressed the accumulation of lipid droplets and downregulated the expression of key adipogenic factors, i.e., peroxisome proliferator-activated receptor γ PPARγ and CCAAT-enhancer binding protein α (C/EBPα), through activating Hh signaling in differentiated 3T3-L1 cells. Furthermore, caudatin and the Hh activator purmorpharmine significantly decreased body weight gain and white adipose tissue (WAT) weight in HFD-induced mice and affected adipogenic markers and Hh signaling mediators in WAT, which were in line with the in vitro experimental results. CONCLUSION: To our best knowledge, it is the first report to demonstrate that caudatin downregulated adipocyte differentiation and suppressed HFD-induced body weight gain through activating the Hh signaling pathway, suggesting that caudatin can potentially counteract obesity.

Garcinone C suppresses colon tumorigenesis through the Gli1-dependent hedgehog signaling pathway.

BACKGROUND: Although garcinone C, a natural xanthone derivative identified in the pericarp of Garcinia mangostana, has been demonstrated to exert different health beneficial activities in oxidative stress and ß-amyloid aggregation, the role of garcinone C in colon tumorigenesis has not been investigated. In addition, aberrant Hedgehog (Hh) signaling activation is associated with tumorigenesis including colon cancer. Here, we hypothesized that garcinone C can prevent colon tumorigenesis through regulating the Hh signaling pathway. METHOD: Colony formation assay and flow cytometry were used to evaluate the effect of garcinone C on the proliferation and cell cycle progression of colon cancer cells. Protein expression of cell cycle related markers and Hh/Gli1 signaling mediators were determined. The regulatory effect of orally administered garcinone C on the Hh/Gli1 signaling pathway and colon tumorigenesis was evaluated in an azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colon cancer animal model. RESULTS: Garcinone C suppressed the proliferation of colon cancer cells, induced G0/G1 cell cycle arrest, as well as regulated the expression of cell cycle-related markers such as cyclin D1, cyclin E, CDK6, and p21. Garcinone C inhibited the expression of Gli1, a key mediator of Hedgehog signaling, and protein kinase B (AKT) phosphorylation in Smo-independent colon cancer cells. In the AOM/DSS-induced colon tumorigenesis model, garcinone C significantly inhibited tumor development, regulated the expression of cell cycle markers and Gli1, and reduced AKT phosphorylation in colon tumor tissues, which is consistent with our in vitro results. CONCLUSION: Garcinone C can suppress colon tumorigenesis in vitro and in vivo through Gli1-dependent non-canonical Hedgehog signaling, suggesting that it may serve as a potent chemopreventive agent against colon tumorigenesis.