Raspberry promotes brown and beige adipocyte development in mice fed high-fat diet through activation of AMP-activated protein kinase (AMPK) alpha 1

Development of brown and beige/brite adipocytes increases thermogenesis and helps to reduce obesity and metabolic syndrome. Our previous study suggests that dietary raspberry can ameliorate metabolic syndromes in diet-induced obese mice. Here, we further evaluated the effects of raspberry on energy expenditure and adaptive thermogenesis and determined whether these effects were mediated by AMP-activated protein kinase (AMPK). Mice deficient in the catalytic subunit of AMPK alpha 1 and wild-type (WT) mice were fed a high-fat diet (HFD) or HFD supplemented with 5% raspberry (RAS) for 10 weeks. The thermogenic program and related regulatory factors in adipose tissue were assessed. RAS improved the insulin sensitivity and reduced fat mass in WT mice but not in AMPK alpha 1(-/-) mice. In the absence of AMPK alpha 1, RAS failed to increase oxygen consumption and heat production. Consistent with this, the thermogenic gene expression in brown adipose tissue and brown-like adipocyte formation in subcutaneous adipose tissue were not induced by RAS in AMPK alpha 1(-/-) mice. In conclusion, AMPK alpha 1 is indispensable for the effects of RAS on brown and beige/brite adipocyte development, and prevention of obesity and metabolic dysfunction. (C) 2018 Elsevier Inc. All rights reserved.