The Aarskog-Scott Syndrome Protein Fgd1 Regulates Podosome Formation and Extracellular Matrix Remodeling in Transforming Growth Factor β-Stimulated Aortic Endothelial Cells
The Aarskog-Scott Syndrome Protein Fgd1 Regulates Podosome Formation and Extracellular Matrix Remodeling in Transforming Growth Factor β-Stimulated Aortic Endothelial Cells
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DOI：
10.1128/mcb.05474-11
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发表时间：
2011-11-01
影响因子：
5.3
通讯作者：
Genot, Elisabeth
中科院分区：
文献类型：
--
作者：
Daubon, Thomas;Buccione, Roberto;Genot, Elisabeth
足质体是一种动态的富含肌动蛋白的黏附质膜微域，具有胞外基质降解活性。在主动脉内皮细胞中，转化生长因子β (tgf - β)可诱导足小体，但其发生机制尚不清楚。据认为，在内皮细胞中，足质体在血管重塑和/或突破解剖屏障中发挥作用。我们在这里证明，在牛主动脉内皮细胞中，cdc42特异性鸟嘌呤交换因子（GEF） Fgd1通过tgf - β表达和调节，诱导cdc42依赖性足体组装。在tgf - β刺激的15分钟内，Fgd1，而不是其他测试的Cdc42 gef，经历酪氨酸磷酸化，与Cdc42结合，并通过接触蛋白依赖机制易位到皮质下细胞骨架。小干扰rna介导的Fgd1敲低抑制tgf - β诱导的Cdc42激活。Fgd1的缺失也减少了足体的形成和相关的基质降解，这些缺陷通过Fgd1的重新表达得以修复。虽然Fgd1的过表达本身并不促进足小体的形成，但它会增强tgf - β诱导的基质降解。我们的研究结果确定Fgd1是tgf - β调节的GEF，因此，它是第一个参与细胞因子诱导的足小体形成过程的GEF。我们的研究结果揭示了Fgd1参与内皮细胞生物学，并为研究其在血管病理生理中的作用开辟了新的途径。
Podosomes are dynamic actin-rich adhesion plasma membrane microdomains endowed with extracellular matrix-degrading activities. In aortic endothelial cells, podosomes are induced by transforming growth factor beta (TGF-beta), but how this occurs is largely unknown. It is thought that, in endothelial cells, podosomes play a role in vessel remodeling and/or in breaching anatomical barriers. We demonstrate here that, in bovine aortic endothelial cells, that the Cdc42-specific guanine exchange factor (GEF) Fgd1 is expressed and regulated by TGF-beta to induce Cdc42-dependent podosome assembly. Within 15 min of TGF-beta stimulation, Fgd1, but none of the other tested Cdc42 GEFs, undergoes tyrosine phosphorylation, associates with Cdc42, and translocates to the subcortical cytoskeleton via a cortactin-dependent mechanism. Small interfering RNA-mediated Fgd1 knockdown inhibits TGF-beta-induced Cdc42 activation. Fgd1 depletion also reduces podosome formation and associated matrix degradation and these defects are rescued by reexpression of Fgd1. Although overexpression of Fgd1 does not promote podosome formation per se, it enhances TGF-beta-induced matrix degradation. Our results identify Fgd1 as a TGF-beta-regulated GEF and, as such, the first GEF to be involved in the process of cytokine-induced podosome formation. Our findings reveal the involvement of Fgd1 in endothelial cell biology and open up new avenues to study its role in vascular pathophysiology.