Cells perceive the physical cues such as perturbations of extracellular matrix (ECM) stiffness, and translate these stimuli into biochemical signals controlling various aspects of cell behavior, which contribute to the physiological and pathological processes of multiple organs. In this study, we tested the hypothesis that during arterial stiffening, vascular smooth muscle cells (SMCs) sense the increase of ECM stiffness, which modulates the cellular phenotype through the regulation in DNA methyltransferases 1 (DNMT1) expression. Moreover, we hypothesized that the mechanisms involve intrinsic stiffening and deficiency in contractility of vascular SMCs. Substrate stiffening was mimicked in vitro with polyacrylamide gels. A contractile-to-synthetic phenotypic transition was induced by substrate stiffening in vascular SMCs through the down-regulation of DNMT1 expression. DNMT1 repression was also observed in the tunica media of mice aortas in an acute aortic injury model and a chronic kidney failure model, as well as in the tunica intima of human carotid arteries with calcified atherosclerotic lesions. DNMT1 inhibition facilitates arterial stiffening in vivo and promotes osteogenic transdifferentiation, calcification and cellular stiffening of vascular SMCs in vitro. These effects may be attributable, at least in part, to the role of DNMT1 in regulating the promoter activities of Transgelin (SM22α) and α-smooth muscle actin (SMA) and the functional contractility of SMCs. We conclude that DNMT1 is a critical regulator that negatively regulates arterial stiffening via maintaining the contractile phenotype of vascular SMCs. This research may facilitate elucidation of the complex crosstalk between vascular SMCs and their surrounding matrix in healthy and in pathological conditions and provide new insights into the implications for potential targeting of the phenotypic regulatory mechanisms in material-related therapeutic applications.

细胞感知诸如细胞外基质（ECM）刚度扰动之类的物理提示，并将这些刺激转化为控制细胞行为各个方面的生化信号，这有助于多个器官的生理和病理过程。在这项研究中，我们测试了以下假设：在动脉硬化期间，血管平滑肌细胞（SMC）感觉到ECM硬度的增加，这通过调节DNA甲基转移酶1（DNMT1）的表达来调节细胞表型。此外，我们假设该机制涉及内在的硬化和血管SMCs收缩力的不足。在体外模拟基材的硬化与聚丙烯酰胺凝胶。通过下调DNMT1表达，血管SMC中的底物变硬诱导了从收缩到合成的表型转变。在急性主动脉损伤模型和慢性肾功能衰竭模型的小鼠主动脉的中膜介质中，以及在具有钙化的动脉粥样硬化病变的人颈动脉的中膜内膜中，也观察到了DNMT1抑制。DNMT1抑制可促进体内动脉硬化，并促进体外血管SMC的成骨转分化，钙化和细胞硬化。这些作用可能至少部分归因于DNMT1在调节Transgelin（SM22α）和α-平滑肌肌动蛋白（SMA）的启动子活性以及SMCs的功能收缩中的作用。我们得出的结论是，DNMT1是通过维持血管SMC的收缩表型来负调节动脉硬化的关键调节剂。这项研究可能有助于阐明健康和病理条件下血管平滑肌细胞及其周围基质之间的复杂串扰，并为在材料相关的治疗应用中潜在靶向表型调节机制的含义提供新的见解。