Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, The Netherlands; Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Université de Paris, Institut Cochin, INSERM, Paris, France.
J Biol Chem. 2020 Dec 18;295(51):17535-17548. doi: 10.1074/jbc.RA120.014868.
The development of a chronic, low-grade inflammation originating from adipose tissue in obese subjects is widely recognized to induce insulin resistance, leading to the development of type 2 diabetes. The adipose tissue microenvironment drives specific metabolic reprogramming of adipose tissue macrophages, contributing to the induction of tissue inflammation. Uncoupling protein 2 (UCP2), a mitochondrial anion carrier, is thought to separately modulate inflammatory and metabolic processes in macrophages and is up-regulated in macrophages in the context of obesity and diabetes. Here, we investigate the role of UCP2 in macrophage activation in the context of obesity-induced adipose tissue inflammation and insulin resistance. Using a myeloid-specific knockout of UCP2 (Ucp2), we found that UCP2 deficiency significantly increases glycolysis and oxidative respiration, both unstimulated and after inflammatory conditions. Strikingly, fatty acid loading abolished the metabolic differences between Ucp2 macrophages and their floxed controls. Furthermore, Ucp2 macrophages show attenuated pro-inflammatory responses toward Toll-like receptor-2 and -4 stimulation. To test the relevance of macrophage-specific Ucp2 deletion in vivo, Ucp2 and Ucp2 mice were rendered obese and insulin resistant through high-fat feeding. Although no differences in adipose tissue inflammation or insulin resistance was found between the two genotypes, adipose tissue macrophages isolated from diet-induced obese Ucp2 mice showed decreased TNFα secretion after ex vivo lipopolysaccharide stimulation compared with their Ucp2 littermates. Together, these results demonstrate that although UCP2 regulates both metabolism and the inflammatory response of macrophages, its activity is not crucial in shaping macrophage activation in the adipose tissue during obesity-induced insulin resistance.
人们普遍认为,肥胖个体脂肪组织中慢性低度炎症的发展会导致胰岛素抵抗,从而引发 2 型糖尿病。脂肪组织微环境驱动脂肪组织巨噬细胞特定的代谢重编程,导致组织炎症的发生。解偶联蛋白 2(UCP2)是一种线粒体阴离子载体,被认为可以分别调节巨噬细胞中的炎症和代谢过程,并在肥胖和糖尿病的情况下在上调。在这里,我们研究了 UCP2 在肥胖诱导的脂肪组织炎症和胰岛素抵抗背景下对巨噬细胞激活的作用。使用髓样细胞特异性 UCP2 敲除(Ucp2),我们发现 UCP2 缺乏显着增加糖酵解和氧化呼吸,无论是在未刺激还是炎症条件下。引人注目的是,脂肪酸加载消除了 Ucp2 巨噬细胞与其 floxed 对照之间的代谢差异。此外,Ucp2 巨噬细胞对 Toll 样受体-2 和 -4 刺激的促炎反应减弱。为了测试体内巨噬细胞特异性 Ucp2 缺失的相关性,将 Ucp2 和 Ucp2 小鼠通过高脂肪喂养肥胖和胰岛素抵抗。尽管两种基因型之间在脂肪组织炎症或胰岛素抵抗方面没有差异,但与 Ucp2 同窝仔相比,饮食诱导肥胖的 Ucp2 小鼠的脂肪组织巨噬细胞在体外脂多糖刺激后 TNFα 分泌减少。总之,这些结果表明,尽管 UCP2 调节巨噬细胞的代谢和炎症反应,但在肥胖诱导的胰岛素抵抗期间,其活性对于塑造脂肪组织中巨噬细胞的激活并不重要。
Cancers (Basel). 2025-1-23
Oxid Med Cell Longev. 2021-2-18
Cell Metab. 2019-9-5
Nature. 2017-2-8
Nat Rev Immunol. 2016-9
Biochim Biophys Acta. 2016-10
J Exp Med. 2016-1-11