In order to maintain tissue homeostasis and functionality, adherent cells need to sense and respond to environmental mechanical stimuli. An important ability that adherent cells need in order to properly sense and respond to mechanical stimuli is the ability to exert contractile stress onto the environment via actin stress fibers. The actin stress fibers form a structural chain between the cells’ environment via focal adhesions and the nucleus via the nuclear lamina. In case one of the links in this chain is missing or aberrant, contractile stress generation will be affected. This is especially the case in laminopathic cells, which have a missing or mutated form of the LMNA gene encoding for part of the nuclear lamina. Using the thin film method combined with sample specific finite element modeling, we quantitatively showed a fivefold lower contractile stress generation of Lmna knockout mouse embryonic fibroblasts (MEFs) as compared to wild-type MEFs. Via fluorescence microscopy it was demonstrated that the lower contractile stress generation was associated with an impaired actin stress fiber organization with thinner actin fibers and smaller focal adhesions. Similar experiments with wild-type MEFs with chemically disrupted actin stress fibers verified these findings. These data illustrate the importance of an organized actin stress fiber network for contractile stress generation and demonstrate the devastating effect of an impaired stress fiber organization in laminopathic fibroblasts. Next to this, the thin film method is expected to be a promising tool in unraveling contractility differences between fibroblasts with different types of laminopathic mutations.

中文翻译：

---

Lmna基因敲除小鼠胚胎成纤维细胞的收缩性低于野生型

为了维持组织稳态和功能，贴壁细胞需要感知并响应环境机械刺激。贴壁细胞正确感知和响应机械刺激所需的一项重要能力是通过肌动蛋白应激纤维将收缩性应激施加到环境中的能力。肌动蛋白应力纤维通过粘着斑在细胞环境与细胞核之间的核层之间形成结构链。如果该链中的某个环节缺失或出现异常，则会影响收缩性压力的产生。在具有LMNA缺失或突变形式的纤溶细胞中尤其如此编码部分核层的基因。使用薄膜方法与样品特定的有限元建模相结合，我们定量地显示了Lmna基因敲除小鼠胚胎成纤维细胞（MEFs）的收缩应力生成量是野生型MEF的五倍。通过荧光显微镜显示，较低的收缩应力产生与肌动蛋白应力纤维组织受损，肌动蛋白纤维更细和粘着斑较小有关。使用具有化学破坏的肌动蛋白应激纤维的野生型MEF进行的类似实验验证了这些发现。这些数据说明了有组织的肌动蛋白应激纤维网络对于产生收缩应激的重要性，并证明了受损的应激纤维组织在lamopathic成纤维细胞中的毁灭性作用。紧接着，薄膜方法有望成为揭示具有不同类型的lamopathic突变的成纤维细胞之间的收缩力差异的有前途的工具。