Stine Rachel R, Shapira Suzanne N, Lim Hee-Woong, Ishibashi Jeff, Harms Matthew, Won Kyoung-Jae, Seale Patrick
Institute for Diabetes, Obesity & Metabolism, Smilow Center for Translational Research, 3400 Civic Center Blvd, Rm. 12-105, Philadelphia, PA, 19104, USA; Department of Cell and Developmental Biology, Smilow Center for Translational Research, 3400 Civic Center Blvd, Rm. 12-105, Philadelphia, PA, 19104, USA.
Institute for Diabetes, Obesity & Metabolism, Smilow Center for Translational Research, 3400 Civic Center Blvd, Rm. 12-105, Philadelphia, PA, 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Blvd, Rm. 12-111, Philadelphia, PA, 19104, USA.
Mol Metab. 2015 Nov 14;5(1):57-65. doi: 10.1016/j.molmet.2015.11.001. eCollection 2016 Jan.
The induction of beige/brite adipose cells in white adipose tissue (WAT) is associated with protection against high fat diet-induced obesity and insulin resistance in animals. The helix-loop-helix transcription factor Early B-Cell Factor-2 (EBF2) regulates brown adipose tissue development. Here, we asked if EBF2 regulates beige fat cell biogenesis and protects animals against obesity.
In addition to primary cell culture studies, we used Ebf2 knockout mice and mice overexpressing EBF2 in the adipose tissue to study the necessity and sufficiency of EBF2 to induce beiging in vivo.
We found that EBF2 is required for beige adipocyte development in mice. Subcutaneous WAT or primary adipose cell cultures from Ebf2 knockout mice did not induce Uncoupling Protein 1 (UCP1) or a thermogenic program following adrenergic stimulation. Conversely, over-expression of EBF2 in adipocyte cultures induced UCP1 expression and a brown-like/beige fat-selective differentiation program. Transgenic expression of Ebf2 in adipose tissues robustly stimulated beige adipocyte development in the WAT of mice, even while housed at thermoneutrality. EBF2 overexpression was sufficient to increase mitochondrial function in WAT and protect animals against high fat diet-induced weight gain.
Taken together, our results demonstrate that EBF2 controls the beiging process and suggest that activation of EBF2 in WAT could be used to reduce obesity.
白色脂肪组织(WAT)中米色/亮白色脂肪细胞的诱导与动物抵抗高脂饮食诱导的肥胖和胰岛素抵抗有关。螺旋-环-螺旋转录因子早期B细胞因子2(EBF2)调节棕色脂肪组织的发育。在此,我们探讨EBF2是否调节米色脂肪细胞的生成并保护动物免受肥胖影响。
除了原代细胞培养研究外,我们还使用EBF2基因敲除小鼠和在脂肪组织中过表达EBF2的小鼠,以研究EBF2在体内诱导米色化的必要性和充分性。
我们发现EBF2是小鼠米色脂肪细胞发育所必需的。来自EBF2基因敲除小鼠的皮下白色脂肪组织或原代脂肪细胞培养物在肾上腺素能刺激后不会诱导解偶联蛋白1(UCP1)或产热程序。相反,在脂肪细胞培养物中过表达EBF2会诱导UCP1表达和类似棕色/米色脂肪的选择性分化程序。即使在热中性环境中饲养,在脂肪组织中转基因表达EBF2也能强烈刺激小鼠白色脂肪组织中米色脂肪细胞的发育。EBF2过表达足以增加白色脂肪组织中的线粒体功能,并保护动物免受高脂饮食诱导的体重增加。
综上所述,我们的结果表明EBF2控制米色化过程,并提示激活白色脂肪组织中的EBF2可用于减轻肥胖。