The endothelium has been established to generate intercellular stresses and suggested to transmit these intercellular stresses through cell-cell junctions, such as VE-Cadherin and ZO-1, for example. Although the previously mentioned molecules reflect the appreciable contributions both adherens junctions and tight junctions are believed to have in endothelial cell intercellular stresses, in doing so they also reveal the obscure relationship that exists between gap junctions and intercellular stresses. Therefore, to bring clarity to this relationship we disrupted expression of the endothelial gap junction connexin 43 (Cx43) by exposing confluent human umbilical vein endothelial cells (HUVECs) to a low (0.2 μg/mL) and high (2 μg/mL) concentration of 2,5-dihydroxychalcone (chalcone), a known Cx43 inhibitor. To evaluate the impact Cx43 disruption had on endothelial cell mechanics we utilized traction force microscopy and monolayer stress microscopy to measure cell-substrate tractions and cell-cell intercellular stresses, respectively. HUVEC monolayers exposed to a low concentration of chalcone produced average normal intercellular stresses that were on average 17% higher relative to control, while exposure to a high concentration of chalcone yielded average normal intercellular stresses that were on average 55% lower when compared to control HUVEC monolayers. HUVEC maximum shear intercellular stresses were observed to decrease by 16% (low chalcone concentration) and 66% (high chalcone concentration), while tractions exhibited an almost 2-fold decrease under high chalcone concentration. In addition, monolayer cell velocities were observed to decrease by 19% and 35% at low chalcone and high chalcone concentrations, respectively. Strain energies were also observed to decrease by 32% and 85% at low and high concentration of chalcone treatment, respectively, when compared to control. The findings we present here reveal for the first time the contribution Cx43 has to endothelial biomechanics.

中文翻译：

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通过连接蛋白 43 破坏探索内皮细胞机制

内皮已被建立以产生细胞间应力，并建议通过细胞 - 细胞连接传递这些细胞间应力，例如 VE-钙粘蛋白和 ZO-1。虽然前面提到的分子反映了粘附连接和紧密连接被认为在内皮细胞细胞间应激中的显着贡献，但这样做也揭示了间隙连接和细胞间应激之间存在的模糊关系。因此，为了澄清这种关系，我们通过将融合的人脐静脉内皮细胞 (HUVEC) 暴露于低 (0.2 μg/mL) 和高 (2 μg/mL) 浓度来破坏内皮间隙连接连接蛋白 43 (Cx43) 的表达2,5-二羟基查尔酮（查尔酮），一种已知的 Cx43 抑制剂。为了评估 Cx43 破坏对内皮细胞力学的影响，我们分别利用牵引力显微镜和单层应力显微镜来测量细胞 - 基质牵引和细胞 - 细胞细胞间应力。暴露于低浓度查尔酮的 HUVEC 单层产生的平均正常细胞间应力比对照平均高 17%，而暴露于高浓度查尔酮产生的平均正常细胞间应力比对照 HUVEC 平均低 55%单层。观察到 HUVEC 最大剪切细胞间应力降低了 16%（低查耳酮浓度）和 66%（高查耳酮浓度），而牵引力在高查耳酮浓度下降低了近 2 倍。此外，在低查耳酮和高查耳酮浓度下，观察到单层细胞速度分别降低了 19% 和 35%。与对照相比，在低浓度和高浓度查耳酮处理下，应变能也分别降低了 32% 和 85%。我们在这里提出的发现首次揭示了 Cx43 对内皮生物力学的贡献。