Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, 28049 Madrid, Spain.
J Cell Biol. 2012 Sep 17;198(6):1011-23. doi: 10.1083/jcb.201203075. Epub 2012 Sep 10.
Epithelial organ morphogenesis involves sequential acquisition of apicobasal polarity by epithelial cells and development of a functional lumen. In vivo, cells perceive signals from components of the extracellular matrix (ECM), such as laminin and collagens, as well as sense physical conditions, such as matrix stiffness and cell confinement. Alteration of the mechanical properties of the ECM has been shown to promote cell migration and invasion in cancer cells, but the effects on epithelial morphogenesis have not been characterized. We analyzed the effects of cell confinement on lumen morphogenesis using a novel, micropatterned, three-dimensional (3D) Madin-Darby canine kidney cell culture method. We show that cell confinement, by controlling cell spreading, limits peripheral actin contractility and promotes centrosome positioning and lumen initiation after the first cell division. In addition, peripheral actin contractility is mediated by master kinase Par-4/LKB1 via the RhoA-Rho kinase-myosin II pathway, and inhibition of this pathway restores lumen initiation in minimally confined cells. We conclude that cell confinement controls nuclear-centrosomal orientation and lumen initiation during 3D epithelial morphogenesis.
上皮组织器官形态发生包括上皮细胞顺序获得顶底极性和功能性管腔的发育。在体内，细胞感知细胞外基质（ECM）成分如层粘连蛋白和胶原蛋白的信号，以及感知物理条件，如基质硬度和细胞约束。已经表明 ECM 的机械性能的改变可促进癌细胞的迁移和侵袭，但对上皮形态发生的影响尚未被描述。我们使用新型微图案化三维（3D）犬肾细胞培养方法分析了细胞约束对管腔形态发生的影响。我们发现，通过控制细胞铺展，细胞约束限制了周围肌动蛋白的收缩性，并在第一次细胞分裂后促进了中心体定位和管腔起始。此外，周围肌动蛋白的收缩性是通过主激酶 Par-4/LKB1 通过 RhoA-Rho 激酶肌球蛋白 II 途径来介导的，并且抑制该途径可恢复最小约束细胞中的管腔起始。我们得出结论，细胞约束控制了三维上皮形态发生过程中的核-中心体取向和管腔起始。
