Supplementary Material for: Electrical Stimulation Directs Migration, Enhances and Orients Cell Division and Upregulates the Chemokine Receptors CXCR4 and CXCR2 in Endothelial Cells

Natural direct current electric fields (DC EFs) within tissues undergoing angiogenesis have the potential to influence vessel formation, but how they affect endothelial cells is not clear. We therefore quantified behaviours of human umbilical vein endothelial cells (HUVEC) and human microvasculature endothelial cells (HMEC) stimulated by EFsin vitro. Both cell types migrated faster and toward the cathode; HUVECs responded to fields as low as 50mV/mm, but the HMEC threshold was 100 mV/mm. Mitosis was stimulated at 50 mV/mm for HMEC and at 150 mV/mm for HUVECs, but the cleavage plane was oriented orthogonal to the field vector at 200 mV/mm for both cell types. That different field strengths induced different cell responses suggests distinct underlying cellular mechanisms. A physiological electric field also upregulated expression of CXCR4 and CXCR2 chemokine receptors and upregulated phosphorylation of both chemokines in HUVEC and HMEC cells. Evidence that DC EFs direct endothelial cell migration, proliferation and upregulate chemokines involved in wound healing suggests a key role for electrical control of capillary production during healing. Our data contribute to the molecular mechanisms by which DC EFs direct endothelial cell behaviour and present a novel signalling paradigm in wound healing, tissue regeneration and angiogenesis-related diseases.

正在经历血管生成的组织内的天然直流电场（DC EFs）具备调控血管形成的潜力，但其对内皮细胞的具体作用机制尚不明确。为此，我们对体外经电场刺激的人脐静脉内皮细胞（HUVEC，Human Umbilical Vein Endothelial Cells）与人体微血管内皮细胞（HMEC，Human Microvasculature Endothelial Cells）的行为进行了定量分析。两类细胞均呈现出更快的迁移速率，且定向向阴极迁移；人脐静脉内皮细胞可对低至50mV/mm的电场产生应答，而人体微血管内皮细胞的电场响应阈值则为100mV/mm。两类细胞的有丝分裂分别在50mV/mm（人体微血管内皮细胞）与150mV/mm（人脐静脉内皮细胞）的电场下被激活，但当电场强度升至200mV/mm时，两类细胞的分裂平面均定向垂直于电场矢量。不同电场强度引发不同细胞应答这一现象，表明其背后存在截然不同的细胞调控机制。生理电场还可上调人脐静脉内皮细胞与人体微血管内皮细胞中CXCR4、CXCR2趋化因子受体的表达水平，并促进两种趋化因子的磷酸化修饰。直流电场可定向引导内皮细胞迁移、增殖，并上调伤口愈合相关趋化因子的表达，这一证据表明，在伤口愈合过程中，电场调控毛细血管生成发挥着关键作用。本研究数据揭示了直流电场定向调控内皮细胞行为的分子机制，同时为伤口愈合、组织再生以及血管生成相关疾病的信号转导研究提供了全新范式。