Intact glucose uptake despite deteriorating signaling in adipocytes with high-fat feeding.
Intact glucose uptake despite deteriorating signaling in adipocytes with high-fat feeding.
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DOI：
10.1530/jme-17-0195
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发表时间：
2018-04
影响因子：
3.5
通讯作者：
Stenkula KG
中科院分区：
文献类型：
--
作者：
Hansson B;Wasserstrom S;Morén B;Periwal V;Vikman P;Cushman SW;Göransson O;Storm P;Stenkula KG
为了捕捉饮食诱导的脂肪细胞体积和数量扩张过程中细胞的即时变化，我们在短期高脂饮食(HFD)干预期间描述了成熟脂肪细胞的特征。雄性C57BL6/J小鼠饲喂高脂饲料2、4、6、14天。糖耐量试验评估全身葡萄糖清除情况。解剖脂肪组织进行RNA-SEQ和库尔特计数细胞大小分布分析。用葡萄糖摄取试验和Western blotting检测脂肪细胞的胰岛素反应，并用共聚焦显微镜观察自噬活性。改用HFD后，脂肪细胞体积立即扩大，两天后就出现全身性胰岛素抵抗，然后是新脂肪细胞的招募。尽管最初非刺激和保存的胰岛素刺激的葡萄糖摄取量增加，但我们观察到胰岛素受体底物-1(IRS-1)和蛋白激酶B(PKB)的磷酸化减少。在HFD后14天，胰岛素刺激的Akt底物160 kDa(AS160)的磷酸化和葡萄糖摄取都被钝化。对脂肪组织的RNA-SEQ分析显示，在第四天，基因表达发生了短暂的变化，包括先前被证明参与自噬的Trp53inp的高度显著上调。我们证实了自噬的增加，测量结果是在HFD后14天，LC3阳性斑点密度增加，p62表达减少。综上所述，HFD迅速诱导全身胰岛素抵抗，而胰岛素刺激的葡萄糖摄取在HFD喂养的6天内保持不变。我们还确认自噬是一种早期的细胞过程，在转换为HFD时可能会影响脂肪细胞的功能。
To capture immediate cellular changes during diet-induced expansion of adipocyte cell volume and number, we characterized mature adipocytes during a short-term high-fat diet (HFD) intervention. Male C57BL6/J mice were fed chow diet, and then switched to HFD for 2, 4, 6 or 14 days. Systemic glucose clearance was assessed by glucose tolerance test. Adipose tissue was dissected for RNA-seq and cell size distribution analysis using coulter counting. Insulin response in isolated adipocytes was monitored by glucose uptake assay and Western blotting, and confocal microscopy was used to assess autophagic activity. Switching to HFD was accompanied by an immediate adipocyte size expansion and onset of systemic insulin resistance already after two days, followed by recruitment of new adipocytes. Despite an initially increased non-stimulated and preserved insulin-stimulated glucose uptake, we observed a decreased phosphorylation of insulin receptor substrate-1 (IRS-1) and protein kinase B (PKB). After 14 days of HFD, both the insulin-stimulated phosphorylation of Akt substrate of 160kDa (AS160) and glucose uptake was blunted. RNA-seq analysis of adipose tissue revealed transient changes in gene expression at day four, including highly significant upregulation of Trp53inp, previously demonstrated to be involved in autophagy. We confirmed increased autophagy, measured as an increased density of LC3-positive puncta and decreased p62 expression after 14 days of HFD. In conclusion, HFD rapidly induced systemic insulin resistance, whereas insulin-stimulated glucose uptake remained intact throughout 6 days of HFD feeding. We also identified autophagy as an early cellular process that potentially influences adipocyte function upon switching to HFD.