VEGF-C/VEGFR3 Regulation of VE-Cadherin in Sinusoidal Angiogenesis and Lymphangiogenesis

VEGF-C/VEGFR3 对 VE-钙粘蛋白在正弦血管生成和淋巴管生成中的调节

• 批准号: 10229242
• 负责人: Derek C Sung
• 金额: $ 5.1万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10229242
• 关键词: VEGF; VEGFR3; Regulation; VE; Cadherin

Research Summary The blood, lymphatic, and sinusoidal vasculatures are molecularly and functionally distinct vascular networks whose normal growth and development are essential to support embryogenesis. While there has been notable effort to understand mechanisms of blood vessel development, relatively little is known about the role of vascular endothelial growth factor (VEGF) receptor 3 (VEGFR3) and its main ligand VEGF-C in sinusoidal development. Despite decades of work on VEGFR2 and VEGFR3 signaling, insights into the field have been complicated by use of various genetic and pharmacologic models with divergent phenotypes. Furthermore, VEGF-C can weakly bind and activate VEGFR2 in addition to inducing VEGFR2-VEGFR3 heterodimers. As a result, the role of VEGF-C in vascular development remains incompletely understood. Therefore, our goal is to determine the role of VEGF-C/VEGFR3 in vascular development and identify novel signaling mechanisms through which it functions through a combination of in vivo mouse and in vitro cell culture studies. We and others have previously identified VEGF-C as an important regulator of fetal liver hematopoiesis. This was primarily attributed to defects in erythroid maturation, however the sinusoids are the only VEGFR3-positive cells in the fetal liver. Strikingly, endothelial deletion of VEGFR3 and vascular endothelial (VE-)cadherin gain- of-function mice both phenocopy VEGF-C knockout mice, suggesting that diminished fetal liver hematopoiesis is in fact due to sinusoidal defects. These mice also have decreased bone marrow (BM) sinusoids. BM defects due to endothelial loss of VEGFR3 are rescued by VE-cadherin haploinsufficiency, demonstrating that VEGFR3 negatively regulates VE-cadherin to promote sinusoidal growth. Whether this process depends on VEGF-C and the signaling mechanisms through which VEGFR3 regulates VE-cadherin remain unclear. Therefore, I hypothesize that VEGF-C activates VEGFR3 to directly and negatively regulate VE-cadherin during sinusoidal angiogenesis and lymphangiogenesis. Aim 1 will test whether haploinsufficiency of VE- cadherin can rescue fetal liver and lymphatic growth defects, as I have demonstrated to be true in the bone marrow sinusoids. Aim 2 will test whether VEGFR3 functions in a VEGF-C-dependent or independent manner in the skin, liver, and bone marrow during sinusoidal angiogenesis and lymphangiogenesis. Finally, Aim 3 will determine the mechanism by which VEGFR3 negatively regulates VE-cadherin through in vitro studies using human lymphatic endothelial cells. Together, these studies will bring novel insights into the mechanism by which VEGF-C/VEGFR3 may regulate VE-cadherin across various vascular beds in multiple organs, which could have important implications for liver regeneration, BM reconstitution, and lymphatic disorders.

研究总结 血液、淋巴管和正弦脉管系统在分子和功能上是不同的血管网络 其正常生长和发育对于支持胚胎发生至关重要。虽然已经有引人注目的 尽管人们努力了解血管发育的机制，但人们对血管发育的作用知之甚少。 正弦曲线中血管内皮生长因子（VEGF）受体3（VEGFR3）及其主要配体VEGF-C 发展。尽管人们对 VEGFR2 和 VEGFR3 信号传导进行了数十年的研究，但对该领域的深入了解仍然存在 由于使用具有不同表型的各种遗传和药理学模型而变得复杂。此外， VEGF-C 除了诱导 VEGFR2-VEGFR3 异二聚体外，还可以微弱地结合并激活 VEGFR2。作为一个 因此，VEGF-C 在血管发育中的作用仍不完全清楚。因此，我们的目标是 确定 VEGF-C/VEGFR3 在血管发育中的作用并确定新的信号传导机制 它通过体内小鼠和体外细胞培养研究的结合发挥作用。我们和 其他人之前已经确定 VEGF-C 是胎儿肝脏造血的重要调节因子。这是 主要归因于红细胞成熟缺陷，但血窦是唯一的 VEGFR3 阳性 胎儿肝脏中的细胞。引人注目的是，VEGFR3 的内皮缺失和血管内皮 (VE-) 钙粘蛋白增益 - 功能丧失小鼠均为 VEGF-C 敲除小鼠，表明胎儿肝脏造血功能减弱 实际上是由于正弦曲线缺陷造成的。这些小鼠的骨髓 (BM) 血窦也减少。骨髓缺陷 由于 VEGFR3 的内皮细胞缺失可通过 VE-钙粘蛋白单倍体不足来挽救，这表明 VEGFR3 负向调节 VE-钙粘蛋白以促进血窦生长。这个过程是否取决于 VEGF-C 和 VEGFR3 调节 VE-钙粘蛋白的信号传导机制仍不清楚。 因此，我推测VEGF-C激活VEGFR3来直接负向调节VE-cadherin 在正窦血管生成和淋巴管生成期间。目标 1 将测试 VE- 是否单倍体不足 钙粘蛋白可以挽救胎儿肝脏和淋巴生长缺陷，正如我在骨骼中所证明的那样 骨髓血窦。目标 2 将测试 VEGFR3 是否以 VEGF-C 依赖或独立的方式发挥作用 在正窦血管生成和淋巴管生成过程中，存在于皮肤、肝脏和骨髓中。最后，目标 3 将 通过体外研究确定 VEGFR3 负向调节 VE-钙粘蛋白的机制 人淋巴管内皮细胞。总之，这些研究将为该机制带来新的见解 其中 VEGF-C/VEGFR3 可能调节多个器官中不同血管床的 VE-钙粘蛋白， 可能对肝再生、骨髓重建和淋巴疾病具有重要意义。