Glycogen synthase kinase-3 negatively regulates tissue factor expression in monocytes interacting with activated platelets
Glycogen synthase kinase-3 negatively regulates tissue factor expression in monocytes interacting with activated platelets
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DOI：
10.1111/j.1538-7836.2011.04236.x
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发表时间：
2011-05-01
影响因子：
10.4
通讯作者：
Evangelista, V.
中科院分区：
文献类型：
--
作者：
di Santo, A.;Amore, C.;Evangelista, V.
背景：在血管损伤部位，单核细胞(MN)与活化的血小板(PLT)相互作用，合成组织因子(TF)，促进血栓形成。在血栓形成的背景下，Tf在MN中表达所需的细胞内信号仍然未知。目的：探讨胰岛素受体下游的糖原合成酶激酶3(GSK3，一种丝氨酸苏氨酸激酶)在血小板诱导的巨噬细胞系(MN)表达转铁蛋白(TF)中的作用。方法：为达到这一目的，我们使用了一种描述良好的人MN-PLT相互作用的体外模型，该模型允许详细分析TF活性、TF蛋白和基因表达。结果：在MN与激活的PLT相互作用过程中：(1)Tf活性、抗原和mRNA在8~10h内一直处于低水平，此后一直显著升高，直至2 4h：(2)根据MN中Tf表达的动力学，GSK3β经历了丝氨酸9的磷酸化过程，这一过程与酶活性下调有关；(3)药物阻断GSK3进一步增加了Tf的表达，并伴随着核内核内核因子-kB的积聚；(4)Wortmannin抑制了PLT诱导的Tf表达，阻断了磷脂酰肌醇3激酶(PI(3)K)的表达；(V)根据胰岛素受体下游GSK3的既定作用，胰岛素以PI(3)K依赖的方式增加PLT诱导的TF表达。结论：GSK3在MN的信号通路中起着分子刹车的作用，导致Tf表达与活化的PLT相互作用。PI(3)K通过Akt依赖的GSK3的磷酸化，缓解了这种停滞，并允许TF基因的表达。这项研究确定了血栓风险和代谢紊乱之间的新的分子联系。
Background: At the site of vascular injury, monocytes (MN) interacting with activated platelets (PLT) synthesize tissue factor (TF) and promote thrombus formation. Intracellular signals necessary for the expression of TF in MN, in the context of a developing thrombus, remain unknown. Objective: The study was designed to investigate the role of the glycogen synthase kinase 3 (GSK3, a serine-threonine kinase) downstream insulin receptor pathway, in PLT-induced TF expression in MN. Methods: To this purpose we used a well-characterized in vitro model of human MN-PLT interactions that allows detailed analysis of TF activity, TF protein and gene expression. Results: The results demonstrated that, in MN interacting with activated PLT: (i) TF activity, antigen and mRNA were low until 8-10 h and dramatically increased thereafter, up to 24 h; (ii) according to the kinetics of TF expression in MN, GSK3 beta undergoes phosphorylation on serine 9, a process associated with down-regulation of enzyme activity; (iii) pharmacological blockade of GSK3 further increased TF expression and was accompanied by increased accumulation of NF-kB, in the nucleus; (iv) blockade of phosphoinositide-3 kinase (PI(3)K) by wortmannin inhibited PLT-induced TF expression; and (v) according to the established role of the GSK3 downstream insulin receptor, insulin increased PLT-induced TF expression in a PI(3)K-dependent manner. Conclusion: GSK3 acts as a molecular brake on the signaling pathway, leading to TF expression in MN interacting with activated PLT. PI(3)K, through Akt-dependent phosphorylation of GSK3, relieves this brake and allows TF gene expression. This study identifies a novel molecular link between thrombotic risk and metabolic disorders.