Logan Caitlin M, Rajakaruna Suren, Bowen Caitlin, Radice Glenn L, Robinson Michael L, Menko A Sue
Thomas Jefferson University, Pathology Anatomy and Cell Biology, Philadelphia, PA, United States.
Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, United States.
Dev Biol. 2017 Aug 1;428(1):118-134. doi: 10.1016/j.ydbio.2017.05.022. Epub 2017 May 26.
Tissue development and regeneration involve high-ordered morphogenetic processes that are governed by elements of the cytoskeleton in conjunction with cell adhesion molecules. Such processes are particularly important in the lens whose structure dictates its function. Studies of our lens-specific N-cadherin conditional knockout mouse (N-cadcKO) revealed an essential role for N-cadherin in the migration of the apical tips of differentiating lens fiber cells along the apical surfaces of the epithelium, a region termed the Epithelial Fiber Interface (EFI), that is necessary for normal fiber cell elongation and the morphogenesis. Studies of the N-cadcKO lens suggest that N-cadherin function in fiber cell morphogenesis is linked to the activation of Rac1 and myosin II, both signaling pathways central to the regulation of cell motility including determining the directionality of cellular movement. The absence of N-cadherin did not disrupt lateral contacts between fiber cells during development, and the maintenance of Aquaporin-0 and increased expression of EphA2 at cell-cell interfaces suggests that these molecules may function in this role. E-cadherin was maintained in newly differentiating fiber cells without interfering with expression of lens-specific differentiation proteins but was not able to replace N-cadherin function in these cells. The dependence of migration of the fiber cell apical domains along the EFI for lens morphogenesis on N-cadherin provides new insight into the process of tissue development.
组织发育和再生涉及由细胞骨架元件与细胞粘附分子共同调控的高阶形态发生过程。这些过程在晶状体中尤为重要,因为晶状体的结构决定其功能。对我们的晶状体特异性N-钙粘蛋白条件性敲除小鼠(N-cadcKO)的研究表明,N-钙粘蛋白在分化的晶状体纤维细胞顶端沿着上皮细胞顶端表面迁移中起着至关重要的作用,该区域称为上皮纤维界面(EFI),这是正常纤维细胞伸长和形态发生所必需的。对N-cadcKO晶状体的研究表明,N-钙粘蛋白在纤维细胞形态发生中的功能与Rac1和肌球蛋白II的激活有关,这两条信号通路都是调节细胞运动性的核心,包括确定细胞运动的方向性。在发育过程中,N-钙粘蛋白的缺失并未破坏纤维细胞之间的侧向接触,水通道蛋白-0的维持以及EphA2在细胞间界面的表达增加表明这些分子可能发挥这一作用。E-钙粘蛋白在新分化的纤维细胞中得以维持,而不干扰晶状体特异性分化蛋白的表达,但无法在这些细胞中替代N-钙粘蛋白的功能。纤维细胞顶端结构域沿EFI迁移对晶状体形态发生依赖于N-钙粘蛋白,这为组织发育过程提供了新的见解。