Microtopography Attenuates Endothelial Cell Proliferation by Regulating MicroRNAs

Endothelial cell (EC) morphology can be regulated by the micro/nano topography in engineered vascular grafts and by hemodynamic forces in the native blood vessels. However, how EC morphology affects miRNA and thus EC functions is not well understood. In this study, we addressed this question by using human umbilical vein endothelial cells (HUVECs) cultured on microgrooves as a model. HUVECs were grown on either microgrooved (with 10 μm width/spacing and 3 μm depth) or smooth surfaces. HUVECs on microgrooved surface had elongated and bipolar morphology, while HUVECs on smooth surface showed cobble stone shape or non-polar morphology. EdU staining indicated that HUVECs with elongated morphology had lower proliferation rate compared to their counterpart cultured on smooth surface. Quantitative PCR analysis demonstrated that the expression of the specific microRNAs (miR-10a, miR-19a, miR-221) that targeted proliferation-related genes was all up-regulated. Consistently, the mRNA levels of their respective target genes, mitogen-activated protein kinase kinase kinase 7, Cyclin D1 and c-kit were significantly reduced by a fold change of 0.12 ± 0.01 (p p 0.05) and 0.76 ± 0.21 (p < 0.05). Other miRNAs such as miR-126 and miR-181a were up-regulated as well, leading to the repression of their targets vascular cell adhesion molecule-1 and prospero homeobox-1. Our results suggested that microgrooved surface may regulate microRNA levels and thus EC functions. These results provide insight into the modulation of EC functions by microtopographic cues, and will facilitate the rational design of microstructured materials for cell and tissue engineering.