The cells of the vascular system are highly sensitive to biophysical cues from their local cellular microenvironment. To engineer improved materials for vascular devices and delivery of cell therapies, a key challenge is to understand the mechanisms that cells use to sense biophysical cues from their environment. Syndecans are heparan sulfate proteoglycans (HSPGs) that consist of a protein core modified with heparan sulfate glycosaminoglycan chains. Due to their presence on the cell surface and their interaction with cytoskeletal and focal adhesion associated molecules, cell surface proteoglycans are well poised to serve as mechanosensors of the cellular microenvironment. Nanotopological cues have become recognized as major regulators of cell growth, migration and phenotype. We hypothesized that syndecan-1 could serve as a mechanosensor for nanotopological cues and can mediate the responsiveness of vascular smooth muscle cells to nanoengineered materials. We created engineered substrates made of polyurethane acrylate with nanogrooves using ultraviolet-assisted capillary force lithography. We cultured vascular smooth muscle cells with knockout of syndecan-1 on engineered substrates with varying compliance and nanotopology. We found that knockout of syndecan-1 reduced alignment of vascular smooth muscle cells to the nanogrooves under inflammatory treatments. In addition, we found that loss of syndecan-1 increased nuclear localization of Yap/Taz and phospho-Smad2/3 in response to nanogrooves. Syndecan-1 knockout vascular smooth muscle cells also had elevated levels of Rho-associated protein kinase-1 (Rock1), leading to increased cell stiffness and an enhanced contractile state in the cells. Together, our findings support that syndecan-1 knockout leads to alterations in mechanosensing of nanotopographical cues through alterations of in rho-associated signaling pathways, cell mechanics and mediators of the Hippo and TGF-β signaling pathways.

血管系统的细胞对其局部细胞微环境的生物物理线索高度敏感。为了设计用于血管装置和细胞疗法的改进材料，一个关键的挑战是了解细胞用来感知来自环境的生物物理线索的机制。多聚糖是硫酸乙酰肝素蛋白聚糖 (HSPG)，由用硫酸乙酰肝素糖胺聚糖链修饰的蛋白质核心组成。由于它们存在于细胞表面以及与细胞骨架和粘着斑相关分子的相互作用，细胞表面蛋白多糖完全可以作为细胞微环境的机械传感器。纳米拓扑线索已被认为是细胞生长、迁移和表型的主要调节因子。我们假设 syndecan-1 可以作为纳米拓扑线索的机械传感器，并可以介导血管平滑肌细胞对纳米工程材料的反应。我们使用紫外线辅助毛细管力光刻技术创建了由聚氨酯丙烯酸酯制成的带有纳米凹槽的工程基板。我们在具有不同顺应性和纳米拓扑结构的工程基质上培养了 Syndecan-1 敲除的血管平滑肌细胞。我们发现，在炎症治疗下，syndecan-1 的敲除会减少血管平滑肌细胞与纳米凹槽的排列。此外，我们发现 syndecan-1 的缺失增加了 Yap/Taz 和磷酸化 Smad2/3 对纳米凹槽的响应的核定位。 Syndecan-1 敲除血管平滑肌细胞的 Rho 相关蛋白激酶 1 (Rock1) 水平也升高，导致细胞硬度增加和细胞收缩状态增强。 总之，我们的研究结果支持 syndecan-1 敲除通过改变 rho 相关信号通路、细胞力学以及 Hippo 和 TGF-β 信号通路的介质而导致纳米地形线索的机械传感改变。