Silence Therapeutics AG, 13125 Berlin, Germany.
Eur J Cell Biol. 2012 Sep;91(9):694-705. doi: 10.1016/j.ejcb.2012.03.010. Epub 2012 May 19.
Several pathways are involved in the control of endothelial cell morphology, endothelial permeability and function in order to maintain vascular homeostasis. Here we report that protein kinase N3 (PKN3) appears to play a pivotal role in maintaining endothelial cell morphology, cell-cell junctions and motility. An RNAi-based cell biological approach in cultured human endothelial cells (HUVEC) revealed that knockdown of PKN3 expression gave rise to cells with divergent cell morphology, impaired locomotion, disturbed adherens junctions (AJ) integrity and irregular actin organization. Notably, knockdown of PKN3 cells led to improper stress fiber formation and marked adhesiveness of intercellular adherens junctions when cells became stimulated with the pro-inflammatory cytokine TNF-α. Moreover, TNF-α-induced ICAM-1 expression on the cell surface was reduced in cells with suppressed PKN3 expression. Finally, loss-of-function for PKN3 appeared to affect Pyk2 phosphorylation in endothelial cells. These observations suggest that PKN3 can be considered a novel protein implicated in remodeling the actin-adherens junction, possibly by linking ICAM-1-signaling with actin/AJ dynamics. We propose that loss of PKN3 function and concomitant aberrations in actin rearrangement may attenuate pro-inflammatory activation of endothelial cells.
多种途径参与了内皮细胞形态、内皮通透性和功能的调控，以维持血管内环境稳定。在这里，我们报告称蛋白激酶 N3（PKN3）似乎在维持内皮细胞形态、细胞-细胞连接和运动方面发挥着关键作用。在培养的人内皮细胞（HUVEC）中，基于 RNAi 的细胞生物学方法表明，PKN3 表达的敲低导致细胞形态发散、运动能力受损、黏附连接完整性受到干扰以及肌动蛋白组织不规则。值得注意的是，当细胞受到促炎细胞因子 TNF-α的刺激时，PKN3 敲低的细胞会导致不当的应力纤维形成和细胞间黏附连接的显著黏附性。此外，在 PKN3 表达受抑制的细胞中，TNF-α诱导的细胞表面 ICAM-1 表达减少。最后，PKN3 的功能丧失似乎会影响内皮细胞中 Pyk2 的磷酸化。这些观察结果表明，PKN3 可以被认为是一种新型的参与重塑肌动球蛋白-黏附连接的蛋白，可能通过将 ICAM-1 信号与肌动蛋白/AJ 动力学联系起来。我们提出，PKN3 功能的丧失以及伴随的肌动蛋白重排异常可能会减弱内皮细胞的促炎激活。
