Endoglin Regulates Endothelial Survival and Capillary Tube Stability

内皮糖蛋白调节内皮细胞存活和毛细管稳定性

• 批准号: 8459636
• 负责人: Nam Y Lee
• 金额: $ 24.9万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8459636
• 关键词: Address; Affinity; Angiogenesis Inhibitors; Area; Basement membrane; Biological; Biological Assay; Biological Models; Biology; Blood Vessels; Blood capillaries; Caspase; Cell Proliferation; Cell Survival; Cell physiology; Coculture Techniques; Complex; Data; Defect; ENG gene; Embryo; Endoglin; Endothelial Cells; Equilibrium; Hereditary hemorrhagic telangiectasia; Human; In Vitro; Inflammation; Ligands; Mediating; Methods; Migration Assay; Molecular; Monitor; Morphogenesis; Mus; Mutation; Outcome; Pathway interactions; Patients; Phase; Phenotype; Play; Process; Proteins; Regulation; Reporting; Research; Research Proposals; Role; Signal Pathway; Signal Transduction; Staging; Structure; System; TGF-beta type I receptor; Testing; Transducers; Transforming Growth Factors; Tube; Vascular Diseases; Work; angiogenesis; base; bone morphogenetic protein 9; capillary; cell behavior; improved; in vitro Model; innovation; insight; migration; novel; protein transport; receptor; response; scaffold; tumor

Specific Aims Transforming growth factor (TGF-¿) superfamily signaling in endothelial cells regulates essential components of angiogenesis and vascular morphogenesis, including proliferation and capillary tube formation. TGF-¿ superfamily ligands exert their regulatory effects through the endothelial cell specific TGF-¿ receptor complex, ALK1 (type I receptor) and endoglin (co-receptor), along with the ubiquitous type I TGF-¿ receptor, ALK5, to activate the canonical Smad 1/5/8 and Smad 2/3 pathways, respectively. TGF-¿ ligands also signal through non-Smad pathways such as MAPKs and PI3K/Akt, although the underlying mechanisms remain obscure. A critical role for endoglin and ALK1 in TGF-¿ signaling in endothelial cells is supported by their mutation resulting in the human vascular disease, hereditary hemorrhagic telangiectasia (HHT1 and 2), embryonic lethal phenotype due to defects in angiogenesis when either endoglin or ALK1 is targeted for deletion in mice, and by the elevated expression of endoglin during inflammation and tumor-induced angiogenesis. While important biological roles for endoglin have been established, the molecular basis for endoglin function in vascular biology remains poorly characterized. Here in vitro angiogenesis assays were employed to investigate precisely when and how endoglin regulates endothelial capillary sprouting and tube formation. Comparison of endoglin-null and wild type endothelial cells revealed that endoglin differentially regulates the stability of capillary sprouts and tubes in response to its physiologically relevant high-affinity ligands, TGF-¿ and BMP-9. Specifically, TGF-¿ resulted in regression of the capillary sprouts and tube structures, primarily through suppression of endoglin-dependent Akt signaling. Conversely, endoglin enhanced Akt signaling in response to BMP-9 to promote capillary stability. These outcomes are attributed to the association between endoglin and the scaffolding/trafficking protein, GIPC, since disrupting their interaction abrogated such endoglin-dependent effects. Given that I recently reported the enhancement of Smad 1/5/8 signaling through GIPC and endoglin, there exists a potential crosstalk between Akt and endoglin-dependent Smad 1/5/8 signaling, which I propose to investigate. Lastly, I discovered a novel interaction between endogenous endoglin and Akt, a finding that will likely yield new facets of endoglin biology. Based upon these preliminary data, I propose the following hypothesis: Endoglin associates with GIPC to promote angiogenesis by stabilizing endothelial capillaries via BMP-9-dependent Akt activation while destabilizing capillaries via TGF-¿-dependent suppression of Akt signaling and cell survival mechanisms. This hypothesis will be addressed by the objectives outlined in two specific aims.

具体目标 内皮细胞中的转化生长因子 (TGF-¿) 超家族信号传导调节 血管生成和血管形态发生的重要组成部分，包括 增殖和毛细管形成。 TGF-¿超家族配体发挥其作用 通过内皮细胞特异性 TGF-¿ 受体复合物 ALK1 发挥调节作用 （I 型受体）和内皮糖蛋白（共受体），以及普遍存在的 I 型 TGF-¿ 受体 ALK5，激活经典的 Smad 1/5/8 和 Smad 2/3 通路， 分别。 TGF-¿ 配体还通过非 Smad 途径（例如 MAPK）发出信号 和 PI3K/Akt，尽管其潜在机制仍不清楚。的关键作用 内皮细胞中 TGF-¿ 信号传导中的内皮糖蛋白和 ALK1 得到其突变的支持 导致人类血管疾病，遗传性出血性毛细血管扩张症（HHT1 2），当任一内皮因子时，由于血管生成缺陷而导致的胚胎致死表型 或 ALK1 在小鼠中被靶向删除，并且通过内皮糖蛋白的表达升高 在炎症和肿瘤诱导的血管生成期间。虽然具有重要的生物学作用 内皮糖蛋白在血管中的功能的分子基础已经建立 生物学的特征仍然很少。这里采用体外血管生成测定 精确研究内皮糖蛋白何时以及如何调节内皮毛细血管出芽 和管的形成。内皮糖蛋白无效和野生型内皮细胞的比较揭示 内皮因子差异调节毛细血管芽和管的稳定性 对其生理相关的高亲和力配体 TGF-¿ 和 BMP-9 的反应。 具体来说，TGF-¿导致毛细血管芽和管结构退化， 主要通过抑制内皮糖蛋白依赖性 Akt 信号传导。相反，内皮糖蛋白 增强 Akt 信号响应 BMP-9 以促进毛细血管稳定性。这些 结果归因于内皮糖蛋白和 支架/运输蛋白，GIPC，因为破坏它们的相互作用就消除了这种 内皮糖蛋白依赖性效应。鉴于我最近报告了 Smad 的增强 1/5/8信号通过GIPC和内皮糖蛋白，之间存在潜在的串扰 Akt 和内皮糖蛋白依赖性 Smad 1/5/8 信号传导，我建议对其进行研究。 最后，我发现了内源性内皮糖蛋白和 Akt 之间的一种新的相互作用，这一发现 这可能会产生内皮糖蛋白生物学的新方面。根据这些初步数据，我 提出以下假设：Endoglin 与 GIPC 结合以促进 通过 BMP-9 依赖性 Akt 激活稳定内皮毛细血管来促进血管生成 同时通过 TGF-¿ 依赖性 Akt 信号传导和细胞抑制来破坏毛细血管的稳定 生存机制。该假设将通过目标来解决 概述了两个具体目标。