Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074, Aachen, Germany.
Institute of Biological Information Processing 2, Forschungszentrum Jülich, 52425, Jülich, Germany.
Sci Rep. 2020 Mar 12;10(1):4574. doi: 10.1038/s41598-020-61242-5.
Keratin intermediate filaments provide mechanical resilience for epithelia. They are nevertheless highly dynamic and turn over continuously, even in sessile keratinocytes. The aim of this study was to characterize and understand how the dynamic behavior of the keratin cytoskeleton is integrated in migrating cells. By imaging human primary keratinocytes producing fluorescent reporters and by using standardized image analysis we detect inward-directed keratin flow with highest rates in the cell periphery. The keratin flow correlates with speed and trajectory of migration. Changes in fibronectin-coating density and substrate stiffness induces concordant changes in migration speed and keratin flow. When keratinocytes are pseudo-confined on stripes, migration speed and keratin flow are reduced affecting the latter disproportionately. The regulation of keratin flow is linked to the regulation of actin flow. Local speed and direction of keratin and actin flow are very similar in migrating keratinocytes with keratin flow lagging behind actin flow. Conversely, reduced actin flow in areas of high keratin density indicates an inhibitory function of keratins on actin dynamics. Together, we propose that keratins enhance persistence of migration by directing actin dynamics and that the interplay of keratin and actin dynamics is modulated by matrix adhesions.
角蛋白中间丝为上皮组织提供机械弹性。然而，它们非常具有动态性，即使在静止的角质细胞中也会不断更新。本研究的目的是描述和理解角蛋白细胞骨架的动态行为如何整合到迁移细胞中。通过对产生荧光报告物的人原代角质细胞进行成像，并使用标准化的图像分析，我们检测到细胞边缘的角蛋白向内流动速度最快。角蛋白流与迁移的速度和轨迹相关。纤连蛋白涂层密度和基质硬度的变化会引起迁移速度和角蛋白流的一致变化。当角质细胞被伪限制在条带上时，迁移速度和角蛋白流会降低，后者不成比例地受到影响。角蛋白流的调节与肌动蛋白流的调节有关。在迁移的角质细胞中，角蛋白和肌动蛋白流的局部速度和方向非常相似，角蛋白流滞后于肌动蛋白流。相反，在角蛋白密度高的区域肌动蛋白流减少表明角蛋白对肌动蛋白动力学具有抑制作用。总之，我们提出角蛋白通过指导肌动蛋白动力学来增强迁移的持久性，并且角蛋白和肌动蛋白动力学的相互作用受基质黏附的调节。
