Thioredoxin-interacting protein is a biomechanical regulator of Src activity: key role in endothelial cell stress fiber formation.
Thioredoxin-interacting protein is a biomechanical regulator of Src activity: key role in endothelial cell stress fiber formation.
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DOI：
10.1161/circresaha.114.301315
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发表时间：
2014-03-28
影响因子：
20.1
通讯作者：
Berk BC
中科院分区：
文献类型：
--
作者：
Spindel ON;Burke RM;Yan C;Berk BC
流体剪切应力（FSS）对内皮细胞（EC）应力纤维形成的调节存在差异，与稳定流动（s-flow）区域相比，扰动流动（d-flow）区域的应力纤维减少。重要的是，应力纤维对几个EC功能至关重要，包括细胞形状、机械信号转导和EC细胞-细胞连接完整性。s-flow诱导应力纤维形成的一个关键介质是Src，它调节下游信号介质，如皮质蛋白磷酸化、黏附激酶和小GTPases的活性。先前我们发现硫氧还蛋白相互作用蛋白（TXNIP，也包括VDUP1和TBP-2）受FSS调控；与s流区相比，d流区TXNIP表达增加。虽然TXNIP最初被描述为其在氧化还原和代谢细胞功能中的作用，但最近的报道显示其α-抑制蛋白结构具有重要的支架功能。基于这些发现，我们假设TXNIP作为生物力学传感器调节Src激酶活性和应激纤维的形成。通过对主动脉和体外培养EC的免疫组化，我们发现TXNIP的表达与Src的活性呈负相关。具体来说，s-flow增加了Src活性和应力纤维的形成，同时降低了TXNIP的表达。相反，d-flow具有相反的效果。我们研究了TXNIP在调节SHP2质膜定位和VE-cadherin结合中的作用，因为SHP2间接调节Src酪氨酸527的去磷酸化，从而抑制Src活性。通过免疫组织化学和免疫沉淀，我们发现TXNIP可以阻止SHP2-VE-cadherin相互作用。总之，这些数据表征了FSS介导的应力纤维形成机制，该机制涉及txnip依赖性VE-cadherin-SHP2-Src途径。
Fluid shear stress (FSS) differentially regulates endothelial cell (EC) stress fiber formation with decreased stress fibers in areas of disturbed-flow (d-flow) compared to steady-flow (s-flow) areas. Importantly, stress fibers are critical for several EC functions including cell shape, mechano-signal transduction, and EC cell-cell junction integrity. A key mediator of s-flow induced stress fiber formation is Src, which regulates downstream signaling mediators such as phosphorylation of cortactin, activity of focal adhesion kinase and small GTPases. Previously we showed that thioredoxin-interacting protein (TXNIP, also VDUP1 and TBP-2) was regulated by FSS; TXNIP expression was increased in d-flow compared to s-flow areas. While TXNIP was originally characterized for its role in redox and metabolic cellular functions, recent reports show important scaffold functions related to its α-arrestin structure. Based on these findings, we hypothesized that TXNIP acts as a biomechanical sensor that regulates Src kinase activity and stress fiber formation. Using en face immunohistochemistry of the aorta and cultured EC, we show inverse relationship between TXNIP expression and Src activity. Specifically, s-flow increased Src activity and stress fiber formation, while it decreased TXNIP expression. In contrast, d-flow had opposite effects. We studied the role of TXNIP in regulating SHP2 plasma membrane localization and VE-cadherin binding, because SHP2 indirectly regulates dephosphorylation of Src tyrosine 527 that inhibits Src activity. Using immunohistochemistry and immunoprecipitation we found that TXNIP prevented SHP2-VE-cadherin interaction. In summary, these data characterize a FSS mediated mechanism for stress fiber formation that involves a TXNIP-dependent VE-cadherin-SHP2-Src pathway.