Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET-UBA, Ciudad Universitaria, Buenos Aires, C1428EHA, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, Buenos Aires, C1425FQB, Argentina.
Sci Rep. 2018 Jun 28;8(1):9788. doi: 10.1038/s41598-018-27948-3.
Mechanical stimuli play a key role in many cell functions such as proliferation, differentiation and migration. In the mammary gland, mechanical signals such as the distension of mammary epithelial cells due to udder filling are proposed to be directly involved during lactation and involution. However, the evolution of focal adhesions -specialized multiprotein complexes that mechanically connect cells with the extracellular matrix- during the mammary gland development, as well as the influence of the mechanical stimuli involved, remains unclear. Here we present the use of an equibiaxial stretching device for exerting a sustained normal strain to mammary epithelial cells while quantitatively assessing cell responses by fluorescence imaging techniques. Using this approach, we explored changes in focal adhesion dynamics in HC11 mammary cells in response to a mechanical sustained stress, which resembles the physiological stimuli. We studied the relationship between a global stress and focal adhesion assembly/disassembly, observing an enhanced persistency of focal adhesions under strain as well as an increase in their size. At a molecular level, we evaluated the mechanoresponses of vinculin and zyxin, two focal adhesion proteins postulated as mechanosensors, observing an increment in vinculin molecular tension and a slower zyxin dynamics while increasing the applied normal strain.
机械刺激在许多细胞功能中起着关键作用，如增殖、分化和迁移。在乳腺中，机械信号，如由于乳房充盈而导致的乳腺上皮细胞的扩张，被认为在泌乳和 involution 期间直接参与。然而，在乳腺发育过程中，焦点粘连的演变——专门的多蛋白复合物，将细胞与细胞外基质机械连接——以及所涉及的机械刺激的影响仍不清楚。在这里，我们提出了使用等双轴拉伸装置对乳腺上皮细胞施加持续的正常应变，同时通过荧光成像技术定量评估细胞反应。使用这种方法，我们研究了 HC11 乳腺细胞在受到类似于生理刺激的机械持续应力时焦点粘连动力学的变化。我们研究了全局应力与焦点粘连组装/解组装之间的关系，观察到在应变下焦点粘连的持久性增强，以及其大小增加。在分子水平上，我们评估了作为机械感受器的两个焦点粘连蛋白 vinculin 和 zyxin 的机械反应，观察到施加的正常应变增加时，vinculin 分子张力增加，zyxin 动力学减慢。
