Dietary Supplementation with Dunaliella Tertiolecta Prevents Whitening of Brown Fat and Controls Diet-Induced Obesity at Thermoneutrality in Mice.

Yukari Yamashita,Yuji Yamaguchi,Yuki Endo,Setsuko Sakaki,Hitoshi Yamashita,Hiroyuki Takenaka,Tamaki Takeuchi,Ayumi Goto

doi:10.3390/nu12061686

Abstract

We investigated the effect of evodiamine-containing microalga Dunaliella tertiolecta (DT) on the prevention of diet-induced obesity in a thermoneutral C57BL/6J male (30 °C). It attenuates the activity of brown adipose tissue (BAT), which accelerates diet-induced obesity. Nine-week-old mice were fed a high-fat diet supplemented with 10 g (Low group) or 25 g (High group) DT powder per kg food for 12 weeks. Compared to control mice without DT supplementation, body weight gain was significantly reduced in the High group with no difference in food intake. Tissue analyses indicated maintenance of multilocular morphology in BAT and reduced fat deposition in liver in DT-supplemented mice. Molecular analysis showed a significant decrease in mammalian target of rapamycin−ribosomal S6 protein kinase signaling pathway in white adipose tissue and upregulation in mRNA expression of brown fat-associated genes including fibroblast growth factor-21 (Fgf21) and uncoupling protein 1 (Ucp1) in BAT in the High group compared to the control. In the experiments using C3H10T1/2 adipocytes, DT extract upregulated mRNA expression of brown fat-associated genes in dose-dependent and time-dependent manners, accompanied by a significant increase in secreted FGF21 levels. Our data show the ability of DT as a nutraceutical to prevent brown fat attenuation and diet-induced obesity in vivo.

Highlights

Adipose tissues are largely responsible for lipid and glucose metabolism, affecting energy homeostasis under the control of various hormones and cytokines in the body
This study demonstrated an upregulation of uncoupling protein 1 (Ucp1) mRNA in inguinal white adipose tissue (WAT) (IWAT) and an increase in its protein level in interscapular brown adipose tissue (BAT) (IBAT) in mice administered with the microalga extract compared to those in control mice, which could be caused by the effect of fucoxanthin
We showed for the first time, the effectiveness of a green microalga Dunaliella tertiolecta (DT) as a nutraceutical for the prevention of diet-induced obesity and hepatic lipid accumulation in vivo without nutraceutical for the prevention of diet-induced obesity and hepatic lipid accumulation in vivo any restriction on food intake

Summary

Introduction

Adipose tissues are largely responsible for lipid and glucose metabolism, affecting energy homeostasis under the control of various hormones and cytokines in the body. Obesity is characterized by excess fat deposition mainly in white adipose tissue (WAT) and subsequently leads to fat accumulation in the liver, which is a serious health risk in industrialized societies [1]. In contrast to WAT, brown adipose tissue (BAT) can undergo thermogenesis mediated by mitochondrial uncoupling protein 1 (UCP1), which maintains homeothermy in mammals in a cold environment [2,3]. As UCP1-mediated thermogenesis dissipates caloric energy as heat, BAT plays a crucial role in energy metabolism. Adult humans have functional BAT, but it was found to decrease with age and showed an inverse correlation with the degree of adiposity [5].

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