Department of Pathology and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
Microvasc Res. 2011 Jan;81(1):34-43. doi: 10.1016/j.mvr.2010.09.001. Epub 2010 Sep 16.
Vascular endothelial growth factor-A (VEGF) typically induces abnormal angiogenesis in the adult, thereby aggravating disease pathology and limiting utility of VEGF for therapeutic angiogenesis. To identify strategies for rectifying defects in pathological VEGF neovessels, we investigated consequences of modulating the Rho GTPase Cdc42. In a mouse skin model of VEGF-driven pathological angiogenesis, transduction with active Cdc42 (L28Cdc42) markedly improved VEGF neovessels, as measured by increased lumen formation, enlarged vessel diameter, and enhanced perfusion of macromolecular tracers. Conversely, transduction with dominant negative Cdc42 (N17Cdc42) impaired endothelial cell (EC) assembly into lumenized blood vessels and reduced neovessel diameter and tracer perfusion. In vitro, active Cdc42 improved coordination between actin filaments and microtubules and enhanced formation of vascular cords, suggesting that active Cdc42 rectifies defects in angiogenesis by improving cytoskeletal dynamics and capillary morphogenesis. Analyses of Cdc42 signaling in microvascular ECs indicated that active Cdc42 also inhibits glycogen synthase kinase-3β (GSK-3β), a multi-functional serine/threonine protein kinase. Pharmacological inhibition of GSK-3β improved vascular cord formation in vitro and promoted proper neovessel formation in vivo comparably to active Cdc42, thus linking GSK-3β inhibition to the mechanism by which active Cdc42 rectifies pathological neovascularization. These studies identify activation of Cdc42 and inhibition of GSK-3β as novel strategies for correcting abnormalities associated with VEGF-driven angiogenesis, and they suggest new approaches for achieving improved therapeutic neovascularization with VEGF.
血管内皮生长因子-A（VEGF）通常会在成年人中引起异常的血管生成，从而加重疾病的病理过程，并限制 VEGF 在治疗性血管生成中的应用。为了确定纠正病理性 VEGF 新生血管缺陷的策略，我们研究了调节 Rho GTPase Cdc42 的后果。在 VEGF 驱动的病理性血管生成的小鼠皮肤模型中，转导活性 Cdc42（L28Cdc42）可显著改善 VEGF 新生血管，表现在管腔形成增加、血管直径增大以及大分子示踪剂的灌注增强。相反，转导显性失活的 Cdc42（N17Cdc42）会损害内皮细胞（EC）组装成有腔的血管，并减少新生血管的直径和示踪剂的灌注。在体外，活性 Cdc42 改善了肌动蛋白丝和微管之间的协调，并增强了血管索的形成，这表明活性 Cdc42 通过改善细胞骨架动力学和毛细血管形态发生来纠正血管生成中的缺陷。对微血管 EC 中的 Cdc42 信号转导的分析表明，活性 Cdc42 还抑制了多功能丝氨酸/苏氨酸蛋白激酶糖原合成酶激酶-3β（GSK-3β）。GSK-3β 的药理学抑制可改善体外血管索的形成，并在体内促进适当的新生血管形成，与活性 Cdc42 相当，从而将 GSK-3β 抑制与活性 Cdc42 纠正病理性新生血管的机制联系起来。这些研究确定了 Cdc42 的激活和 GSK-3β 的抑制是纠正与 VEGF 驱动的血管生成相关的异常的新策略，并为实现 VEGF 治疗性血管生成的改善提供了新方法。
