Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Leipzig, Germany.
Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Leipzig, Germany; Divisions of Endocrinology and Nephrology, University of Leipzig, Leipzig, Germany.
Mol Cell Endocrinol. 2018 Jan 15;460:181-188. doi: 10.1016/j.mce.2017.07.022. Epub 2017 Jul 26.
Vaspin expression is increased in white adipose tissue (WAT) of diet-induced obese mice and rats and is supposed to compensate HFD-induced inflammatory processes and insulin resistance in adipose tissue by counteracting pro-inflammatory gene expression in obesity. Multiple studies have also demonstrated strong anti-inflammatory effects in vascular and skin cells. Here, we used vaspin treated 3T3-L1 murine adipocytes as well as 3T3-L1 cells with stable vaspin expression to investigate the effect of exogenous and endogenous vaspin on inflammatory processes and insulin signaling in adipocytes. Our stably transfected cells secreted significant amounts of vaspin which was in the physiological range of ∼0.5 ng/ml in cell supernatants. Adipocyte differentiation was not affected by vaspin as expression of adipogenic marker genes as well as lipid accumulation after full differentiation was similar to control cells. We found that IL-1β induced expression and secretion of pro-inflammatory cytokines, such as IL-6, MCP1 and TNFα was significantly blunted in vaspin expressing 3T3-L1 cells. Treatment of 3T3-L1 cells with exogenous vaspin resulted in reduced cytokine-induced activation of the intracellular and pro-inflammatory NFκB signaling cascades (IKKα/β, IκB and NFκB). Moreover, endogenous vaspin positively affected insulin signaling by increasing insulin-stimulated phosphorylation of the key mediator protein kinase B (AKT). Together, we demonstrate anti-inflammatory effects of vaspin in 3T3-L1 adipocytes as well as increased insulin signaling by endogenous expression or exogenous treatment. The results provide evidence for potent anti-inflammatory action of vaspin not only in vascular cells but also in adipose tissue.
脂联素在饮食诱导肥胖的小鼠和大鼠的白色脂肪组织(WAT)中的表达增加,被认为可以通过抵消肥胖中促炎基因的表达来补偿高脂肪饮食诱导的脂肪组织中的炎症过程和胰岛素抵抗。多项研究还表明,脂联素在血管和皮肤细胞中具有很强的抗炎作用。在这里,我们使用脂联素处理的 3T3-L1 鼠脂肪细胞以及稳定表达脂联素的 3T3-L1 细胞来研究外源性和内源性脂联素对脂肪细胞中炎症过程和胰岛素信号的影响。我们稳定转染的细胞分泌大量脂联素,其在细胞上清液中的生理范围内约为 0.5ng/ml。脂联素对脂肪细胞分化没有影响,因为脂肪生成标记基因的表达以及完全分化后的脂质积累与对照细胞相似。我们发现,脂联素表达的 3T3-L1 细胞中,IL-1β诱导的促炎细胞因子(如 IL-6、MCP1 和 TNFα)的表达和分泌显著减弱。外源性脂联素处理 3T3-L1 细胞导致细胞内和促炎 NFκB 信号级联(IKKα/β、IκB 和 NFκB)的细胞因子诱导激活减少。此外,内源性脂联素通过增加关键介体蛋白激酶 B(AKT)的胰岛素刺激磷酸化,正向影响胰岛素信号。总之,我们证明了脂联素在 3T3-L1 脂肪细胞中的抗炎作用,以及内源性表达或外源性处理增加胰岛素信号。这些结果为脂联素不仅在血管细胞中而且在脂肪组织中具有强大的抗炎作用提供了证据。