QUANTITATIVE STUDIES OF ENDOTHELIAL-CELL ADHESION - DIRECTIONAL REMODELING OF FOCAL ADHESION SITES IN RESPONSE TO FLOW FORCES
QUANTITATIVE STUDIES OF ENDOTHELIAL-CELL ADHESION - DIRECTIONAL REMODELING OF FOCAL ADHESION SITES IN RESPONSE TO FLOW FORCES
复制标题
DOI：
10.1172/jci117197
复制
发表时间：
1994-05-01
影响因子：
15.9
通讯作者：
GRIEM, ML
中科院分区：
文献类型：
--
作者：
DAVIES, PF;ROBOTEWSKYJ, A;GRIEM, ML
通过串联扫描共聚焦显微镜和数字化图像分析技术，在培养的内皮细胞中观察到粘着斑位点，这些技术可提供活细胞中粘着斑位点面积和形态的实时图像。图像减法显示，在存在单向稳定层流（剪切应力[τ]=10达因/平方厘米）的情况下，相当一部分粘着斑位点沿流动方向发生重塑。相比之下，对照（无流动）细胞的粘着斑无特定方向地重塑。在受到10达因/平方厘米剪切应力的融合单层细胞中，细胞在7 - 9小时后开始沿流动方向重新排列。这伴随着细胞内应力纤维的重新分布、单个粘着斑位点的排列以及较小位点的融合，导致每个细胞的粘着斑数量减少但面积增大。在相同细胞中，根据粘着斑接触面积以及细胞膜与基质之间的分离距离反复计算细胞粘附力，在短期（30分钟）或长期（≤24小时）的流动暴露期间，其变化<10%。与这些测量结果一致，每个位点重塑时粘着斑面积的增减大致相当。当玻璃基质涂有明胶时，在流动过程中（τ = 10达因/平方厘米）重塑速率被抑制47%。这些研究：（a）揭示了粘着斑的动态特性；（b）表明在内皮细胞基底面的这些位点对施加于相对（管腔面）细胞表面的摩擦剪切应力具有急性和慢性响应；（c）提示粘着斑复合物的成分可能是与细胞骨架偶联的机械响应元件。
Focal adhesion sites were observed in cultured endothelial cells by tandem scanning confocal microscopy and digitized image analysis, techniques that provide real-time images of adhesion site area and topography in living cells. Image subtraction demonstrated that in the presence of unidirectional steady laminar flow (shear stress [tau] = 10 dyn/cm(2)) a substantial fraction of focal adhesion sites remodeled in the direction of flow. In contrast, focal adhesions of control (no flow) cells remodeled without preferred direction. In confluent monolayers subjected to shear stresses of 10 dyn/cm(2), cells began to realign in the direction of flow after 7-9 h. This was accompanied by redistribution of intracellular stress fibers, alignment of individual focal adhesion sites, and the coalescence of smaller sites resulting in fewer, but larger, focal adhesions per cell. Cell adhesion, repeatedly calculated in the same cells as a function of the areas of focal contact and the separation distances between membrane and substratum, varied by < 10% during both short (30 min), or prolonged (less than or equal to 24 h), periods of exposure to flow. Consistent with these measurements, the gains and losses of focal adhesion area as each site remodeled were approximately equivalent. When the glass substratum was coated with gelatin, rates of remodeling were inhibited by 47% during flow (tau = 10 dyn/cm(2)). These studies: (a) reveal the dynamic nature of focal adhesions; (b) demonstrate that these sites at the ablumenal endothelial membrane are both acutely and chronically responsive to frictional shear stress forces applied to the opposite (lumenal) cell surface; and (c) suggest that components of the focal adhesion complex may be mechanically responsive elements coupled to the cytoskeleton.