Verma Deepika, Bajpai Vivek K, Ye Nannan, Maneshi Mohammad M, Jetta Deekshitha, Andreadis Stelios T, Sachs Frederick, Hua Susan Z
Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY 14260, USA; Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY 14260, USA.
Department of Chemical and Biological Engineering, University at Buffalo, Buffalo, NY 14260, USA.
Exp Cell Res. 2017 Oct 15;359(2):327-336. doi: 10.1016/j.yexcr.2017.08.009. Epub 2017 Aug 10.
Adherens junctions (AJs) are a key structural component for tissue organization and function. Under fluid shear stress, AJs exhibit dynamic assembly/disassembly, but how shear stress couples to AJs is unclear. In MDCK cells we measured simultaneously the forces in cytoskeletal α-actinin and the density and length of AJs using a genetically coded optical force sensor, actinin-sstFRET, and fluorescently labeled E-cadherin (E-cad). We found that shear stress of 0.74dyn/cm for 3h significantly enhanced E-cad expression at cell-cell contacts and this phenomenon has two phases. The initial formation of segregated AJ plaques coincided with a decrease in cytoskeletal tension, but an increase in tension was necessary for expansion of the plaques and the formation of continuous AJs in the later phase. The changes in cytoskeletal tension and reorganization appear to be an upstream process in response to flow since it occurred in both wild type and dominant negative E-cad cells. Disruption of F-actin with a Rho-ROCK inhibitor eliminated AJ growth under flow. These results delineate the shear stress transduction paths in cultured cells, which helps to understand pathology of a range of diseases that involve dysfunction of E-cadherin.
黏着连接（AJs）是组织构建和功能的关键结构组成部分。在流体剪切应力作用下，AJs会出现动态组装/拆卸，但剪切应力如何与AJs相互作用尚不清楚。在MDCK细胞中，我们使用基因编码的光学力传感器肌动蛋白-sstFRET和荧光标记的E-钙黏蛋白（E-cad），同时测量细胞骨架α-肌动蛋白中的力以及AJs的密度和长度。我们发现，0.74dyn/cm的剪切应力作用3小时可显著增强细胞间接触处的E-cad表达，且这一现象具有两个阶段。分离的AJ斑块的初始形成与细胞骨架张力的降低同时发生，但在后期阶段，斑块的扩展和连续AJs的形成需要张力增加。细胞骨架张力的变化和重组似乎是对流动的上游响应过程，因为在野生型和显性负性E-cad细胞中均会发生。用Rho-ROCK抑制剂破坏F-肌动蛋白可消除流动条件下AJ的生长。这些结果描绘了培养细胞中的剪切应力转导途径，有助于理解一系列涉及E-钙黏蛋白功能障碍的疾病的病理机制。
