Increased endothelial cell (EC) apoptosis is associated with the development of atherosclerotic plaques that develop predominantly at sites exposed to disturbed flow (DF). Strategies to promote EC survival may therefore represent a novel therapeutic approach in cardiovascular disease. Nitric oxide (NO) and β-catenin have both been shown to promote cell survival and they interact in ECs as we previously demonstrated. Here we investigated the physiological role of β-catenin as a mediator of NO-induced cell survival in ECs. We found that β-catenin depleted human umbilical vein ECs (HUVEC) stimulated with pharmacological activators of endothelial NO synthase (eNOS) showed a reduction in eNOS phosphorylation (Ser1177) as well as reduced intracellular cyclic guanosine monophosphate levels compared to control cells in static cultures. In addition, β-catenin depletion abrogated the protective effects of the NO donor, S-nitroso-N-acetylpenicillamine, during TNFα- and H₂O₂-induced apoptosis. Using an orbital shaker to generate shear stress, we confirmed eNOS and β-catenin interaction in HUVEC exposed to undisturbed flow and DF and showed that β-catenin depletion reduced eNOS phosphorylation. β-catenin depletion promoted apoptosis exclusively in HUVEC exposed to DF as did inhibition of soluble guanylate cyclase (sGC) or β-catenin transcriptional activity. The expression of the pro-survival genes, Bcl-2 and survivin was also reduced following inhibition of β-catenin transcriptional activity, as was the expression of eNOS. In conclusion, our data demonstrate that β-catenin is a positive regulator of eNOS activity and cell survival in human ECs. sGC activity and β-catenin-dependent transcription of Bcl-2, survivin, BIRC3 and eNOS are essential to maintain cell survival in ECs under DF.

内皮细胞（EC）凋亡的增加与动脉粥样硬化斑块的形成有关，该斑块主要在暴露于扰动血流（DF）的部位发展。因此，促进EC存活的策略可能代表了心血管疾病的一种新颖的治疗方法。一氧化氮（NO）和β-连环蛋白均已显示出可促进细胞存活，并且它们在EC中相互作用，如我们先前所证明的。在这里，我们研究了β-catenin作为EC诱导NO诱导的细胞存活的介质的生理作用。我们发现，与静态培养中的对照细胞相比，用内皮一氧化氮合酶（eNOS）药理激活剂刺激的β-catenin耗竭的人脐静脉内皮细胞（HUVEC）显示出eNOS磷酸化（Ser1177）降低以及细胞内环鸟苷单磷酸水平降低。 。此外，₂ O ₂诱导的细胞凋亡。使用轨道振动器产生切应力，我们证实了暴露于不受干扰的流动和DF的HUVEC中eNOS和β-catenin的相互作用，并表明β-catenin的消耗减少了eNOS的磷酸化。β-catenin耗竭仅在暴露于DF的HUVEC中促进凋亡，抑制可溶性鸟苷酸环化酶（sGC）或β-catenin转录活性也是如此。抑制β-catenin转录活性后，eNOS的表达也降低了生存前基因Bcl-2和survivin的表达。总之，我们的数据表明，β-catenin是人类EC中eNOS活性和细胞存活的正向调节剂。sGC活性和Bcl-2，survivin，BIRC3和eNOS的β-catenin依赖性转录对于维持DF下EC的细胞存活至关重要。