Liang Elena I, Mah Emma J, Yee Albert F, Digman Michelle A
Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA.
Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, California 92697, USA.
Integr Biol (Camb). 2017 Feb 20;9(2):145-155. doi: 10.1039/c6ib00193a.
Selective cell adhesion is desirable to control cell growth and migration on biomedical implants. Mesenchymal cell migration is regulated through focal adhesions (FAs) and can be modulated by their microenvironment, including changes in surface topography. We use the Number and Molecular Brightness (N&B) imaging analysis to provide a unique perspective on FA assembly and disassembly. This imaging analysis generates a map of real-time fluctuations of protein monomers, dimers, and higher order aggregates of FA proteins, such as paxillin during assembly and disassembly. We show a dynamic view of how nanostructured surfaces (nanoline gratings or nanopillars) regulate single molecular dynamics. In particular, we report that the smallest nanopillars (100 nm spacing) gave rise to a low population of disassembling adhesion clusters of ∼2 paxillin proteins whereas the larger nanopillars (380 nm spacing) gave rise to a much larger population of larger disassembling clusters of ∼3-5 paxillin proteins. Cells were more motile on the smaller nanopillars (spaced 100-130 nm apart) compared to all other surfaces studied. Thus, physical nanotopography influences cell motility, adhesion size, and adhesion assembly and disassembly. We report for the first time, with single molecular detection, how nanotopography influences cell motility and protein reorganization in adhesions.
在生物医学植入物上，选择性细胞黏附对于控制细胞生长和迁移是很有必要的。间充质细胞迁移通过黏着斑（FAs）进行调节，并且可以被其微环境所调控，包括表面形貌的变化。我们使用数量与分子亮度（N&B）成像分析，来提供关于黏着斑组装和解聚的独特视角。这种成像分析生成了一幅关于FA蛋白（如桩蛋白）在组装和解聚过程中蛋白质单体、二聚体及更高阶聚集体实时波动的图谱。我们展示了纳米结构表面（纳米线光栅或纳米柱）如何调节单分子动力学的动态视图。特别地，我们报道最小的纳米柱（间距100 nm）导致约2个桩蛋白组成的低数量解聚黏附簇，而较大的纳米柱（间距380 nm）导致约3 - 5个桩蛋白组成的数量多得多的较大解聚簇。与所研究的所有其他表面相比，细胞在较小的纳米柱（间距100 - 130 nm）上更具迁移性。因此，物理纳米形貌会影响细胞迁移性、黏附大小以及黏附组装和解聚。我们首次通过单分子检测报道了纳米形貌如何影响细胞迁移性以及黏附中的蛋白质重组。
