Endothelial Cells (ECs) form cohesive cellular lining of the vasculature and play essential roles in both developmental processes and pathological conditions. Collective migration and proliferation of endothelial cells (ECs) are key processes underlying endothelialization of vessels as well as vascular graft, but the complex interplay of mechanical and biochemical signals regulating these processes are still not fully elucidated. While surface topography and biochemical modifications have been used to enhance endothelialization in vitro, thus far such single-modality modifications have met with limited success. As combination therapy that utilizes multiple modalities has shown improvement in addressing various intractable and complex biomedical conditions, here, we explore a combined strategy that utilizes topographical features in conjunction with pharmacological perturbations. We characterized EC behaviors in response to micrometer-scale grating topography in concert with pharmacological perturbations of endothelial adherens junctions (EAJ) regulators. We found that the protein tyrosine phosphatase, PTP1B, serves as a potent regulator of EAJ stability, with PTP1B inhibition synergizing with grating topographies to modulate EAJ rearrangement, thereby augmenting global EC monolayer sheet orientation, proliferation, connectivity, and collective cell migration. Our data delineates the crosstalk between cell−ECM topography sensing and cell−cell junction integrity maintenance and suggests that the combined use of grating topography and PTP1B inhibitor could be a promising strategy for promoting collective EC migration and proliferation.

Rationale:Failure of small synthetic vascular grafts is largely due to late endothelialization and has been an ongoing challenge in the treatment of cardiovascular diseases. Objective:Previous strategies developed to promote graft endothelialization include surface topographical modulation and biochemical modifications. However, these have been met with limited success. Importantly, although the integrity of Endothelial Cell (EC) monolayer is crucial for endothelialization, the crosstalk between surface topography and cell-cell connectivity is still not well understood. Here we explored a combined strategy that utilizes both topographical features and pharmacological perturbations. Methods and result:We characterized EC behaviors in response to micron-scale grating topography in conjunction with pharmacological perturbations of endothelial adherens junctions (EAJ) regulators. We studied the EA.hy 926 cell-cell junctions and monolayer integrity using the junctional markers upon the inhibitory effect of EAJ regulator on both planar and grating topographies substrates.We identified a protein tyrosine phosphatase, PTP1B, as a potent regulator of EAJ stability. Next, we studied the physiologically relevant behaviors of EC using primary human coronary arterial endothelial cells (HCAEC). Our results showed that PTP1B inhibition synergized with grating topographies to modulate EAJ rearrangement, thereby controlling global EC monolayer sheet orientation, connectivity and collective cell migration to promote endothelialization.Our results showed that PTP1B inhibition synergized with grating topographies to modulate EAJ rearrangement, thereby controlling global EC monolayer sheet orientation, connectivity and collective cell migration and proliferation. Conclusion:The synergistic effect of PTP1B inhibition and grating topographies could be useful for the promotion of endothelialization by enhancing EC migration and proliferation. IntroductionHealthy blood vessels are covered by a contiguous monolayer of endothelial cells (ECs), which maintain vasculature hemostasis and serve as a blood-compatible interface. Injured arteries and the associated EC malfunctions result in inflammatory responses, subsequent vessel thickening due to the migration and proliferation of smooth muscle cells, plaque formation, and partial or complete occlusion of the vessels [1]. Such atherosclerotic processes underlie peripheral and cardiovascular diseases, stroke, and myocardial infarction which are among the most prevalent causes of death worldwide [2,3]. Among the available treatment options, the replacement of the occluded vessel with either an autologous vein or a synthetic vascular graft has been widely practiced. However, while the implantation of large vessels has been a standard procedure, synthetic small vascular graft (diameter <6 mm) has remained problematic. The primary cause of small graft failure has been attributed to the lack of proper endothelialization [4] [5] [6]. Thus, there remains an unmet clinical need for a small vascular gra...

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