Seebach J, Dieterich P, Luo F, Schillers H, Vestweber D, Oberleithner H, Galla H J, Schnittler H J
Institut für Biochemie, WWU-Münster, Germany.
Lab Invest. 2000 Dec;80(12):1819-31. doi: 10.1038/labinvest.3780193.
It has been suggested that increasing levels of shear stress could modify endothelial permeability. This might be critical in venous grafting and in the pathogenesis of certain vascular diseases. We present a novel setup based on impedance spectroscopy that allows online investigation of the transendothelial electrical resistance (TER) under pure laminar shear stress. Shear stress-induced change in TER was associated with changes in cell motility and cell shape as a function of time (morphodynamics) and accompanied by a reorganization of catenins that regulate endothelial adherens junctions. Confluent cultures of porcine pulmonary trunk endothelial cells typically displayed a TER between 6 and 15 ohms cm2 under both resting conditions and low shear stress levels (0.5 dyn/cm2). Raising shear stress to the range of 2 to 50 dyn/cm2 caused a transient 2% to 15% increase in TER within 15 minutes that was accompanied by a reduction in cell motility. Subsequently, TER slowly decreased to a minimum of 20% below the starting value. During this period, acceleration of shape change occurred. In the ensuing period, TER values recovered, reaching control levels within hours and associated with an entire deceleration of shape change. A heterogeneous distribution of alpha-, beta-, and gamma-catenin, main components of the endothelial adherens type junctions, was also observed, indicating a differentiated regulation of shear stress-induced junction rearrangement. Additionally, catenins were partly colocalized with beta-actin at the plasma membrane, indicating migration activity of these subcellular parts. Shear stress, even at peak levels of 50 dyn/cm2, did not cause intercellular gap formation. These data show that endothelial monolayers exposed to increased levels of laminar shear stress respond with a shear stress-dependent regulation of permeability and a reorganization of junction-associated proteins, whereas monolayer integrity remains unaffected.
有人提出，剪切应力水平的增加可能会改变内皮通透性。这在静脉移植和某些血管疾病的发病机制中可能至关重要。我们提出了一种基于阻抗光谱的新型装置，该装置允许在纯层流剪切应力下在线研究跨内皮电阻（TER）。剪切应力诱导的TER变化与细胞运动性和细胞形状随时间的变化（形态动力学）相关，并伴随着调节内皮黏附连接的连环蛋白的重新组织。猪肺动脉内皮细胞的汇合培养物在静息条件和低剪切应力水平（0.5达因/平方厘米）下，TER通常在6至15欧姆·平方厘米之间。将剪切应力提高到2至50达因/平方厘米的范围会导致TER在15分钟内短暂增加2%至15%，同时细胞运动性降低。随后，TER缓慢下降至起始值以下至少20%。在此期间，形状变化加速。在随后的时期，TER值恢复，在数小时内达到对照水平，并与形状变化的完全减速相关。还观察到内皮黏附型连接的主要成分α-、β-和γ-连环蛋白的异质分布，表明对剪切应力诱导的连接重排有差异化调节。此外，连环蛋白部分与β-肌动蛋白在质膜处共定位，表明这些亚细胞部分的迁移活性。即使在50达因/平方厘米的峰值水平下，剪切应力也不会导致细胞间间隙形成。这些数据表明，暴露于增加的层流剪切应力水平的内皮单层会以剪切应力依赖性的通透性调节和连接相关蛋白的重新组织做出反应，而单层完整性不受影响。
