Regulation of Wnt Signaling by PAP2b During Angiogenesis

血管生成过程中 PAP2b 对 Wnt 信号传导的调节

• 批准号: 7840532
• 负责人: KISHORE K WARY
• 金额: $ 30.1万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7840532
• 关键词: 1,2-diacylglycerol; Acquired Immunodeficiency Syndrome; Adhesions; Affect; Atherosclerosis; Biological Assay; Biological Models; Biological Process; Blood Vessels; Cell Adhesion; Cell Communication; Cell membrane; Cell-Cell Adhesion; Cells; Complex; Cultured Cells; Data; Diabetic Retinopathy; Diglycerides; Down-Regulation; Embryo; Embryonic Development; Endothelial Cells; Event; Exhibits; Fibronectins; Gene Silencing; Genes; Genetic Transcription; Glioblastoma; Heart Diseases; Infertility; Integrins; Interleukin-8; Link; Lipids; Mediating; Membrane Proteins; Molecular; Mus; Pathologic Neovascularization; Phosphatidate Phosphatase; Phosphatidic Acid; Phosphoric Monoester Hydrolases; Physiological; Placenta; Play; Primary Neoplasm; Proteins; Psoriasis; Regulation; Rheumatoid Arthritis; Role; Scleroderma; Signal Pathway; Signal Transduction; Stream; Stroke; Structure; System; Testing; Transgenic Mice; Ulcer; Wound Healing; Yolk Sac; angiogenesis; base; beta catenin; catenin p120ctn protein; gain of function; inorganic phosphate; lipid metabolism; lipid phosphate phosphatase; loss of function; lymphoid enhancer-binding factor 1; protein complex; tumor growth; tumor progression

DESCRIPTION (provided by applicant): Angiogenesis, or the remodeling of preexisting quiescent blood vessel, is critical for embryonic development, wound healing, and various pathological conditions including tumor progression and atherosclerosis. We propose to study in molecular terms, the function of phosphatidic acid phosphatase 2b (PAP2b), a plasma- membrane protein that we discovered in a functional assay of angiogenesis. The PAP2b protein is expressed by endothelial cells, exhibits a cell adhesion sequence, and dephosphorylates phosphatidic acid phosphate (PAP) into diacylglycerol and phosphate, that has been implicated in signal transduction and lipid metabolism. The Pap2b gene inactivation is early embryonic lethal (die around E7.5 day) due to lack of functional vasculature. PAP2b is the first lipid phosphate phosphatase protein that is linked to the Wnt signaling pathway. We found that PAP2b is expressed by a subset of primary tumors, and over-expression of PAP2b supports tumor growth and angiogenesis. We observe that PAP2b interacts with p120catenin and promotes cell-cell-interactions, in turn, induces protein complex formation between beta-catenin and lymphoid enhancer-binding factor-1 (LEF-1), this event leads to fibronectin and IL-8 synthesis and secretion. Based upon our preliminary data, we hypothesize that during angiogenesis PAP2b plays a key role in the formation and organization of adhesion structures connecting endothelial cells. The mechanisms include the ability of PAP2b to form and organize large molecular complex, interact with a subset of integrins, and mediate synthesis of fibronectin through LEF-1 transcriptional machinery. The overall aim of this proposal is to determine the mechanism by which the PAP2b interacts with p120catenin, and mediates synthesis of fibronectin. We propose to test our hypothesis through two major specific aims: (1) Characterize the mechanism by which PAP2b interacts with p120catenin, alter LEF-transcription, and induce expression of fibronectin and IL-8, and (2) Examine the functional consequences of conditional deletion of Pap2b gene in the mice using Tie-2/Cre system. Examine the consequences of SiRNA mediated down-regulation of PAP2b using endothelial cells. We anticipate that our studies will further our understanding of the role of endothelial PAP2b in physiological and pathological angiogenesis. Together, these studies are expected to reveal a new target for anti-angiogenic molecular therapy.

描述（由申请人提供）：血管生成或预先存在的静止血管的重塑对于胚胎发育、伤口愈合以及包括肿瘤进展和动脉粥样硬化在内的各种病理状况至关重要。我们建议从分子角度研究磷脂酸磷酸酶 2b (PAP2b) 的功能，这是我们在血管生成功能测定中发现的一种质膜蛋白。 PAP2b 蛋白由内皮细胞表达，表现出细胞粘附序列，并将磷脂酸磷酸 (PAP) 去磷酸化为二酰甘油和磷酸盐，这与信号转导和脂质代谢有关。由于缺乏功能性脉管系统，Pap2b 基因失活会导致早期胚胎死亡（E7.5 天左右死亡）。 PAP2b 是第一个与 Wnt 信号通路相关的脂质磷酸酶蛋白。我们发现 PAP2b 在原发性肿瘤的亚群中表达，PAP2b 的过度表达支持肿瘤生长和血管生成。我们观察到PAP2b与p120连环蛋白相互作用并促进细胞间相互作用，进而诱导β-连环蛋白和淋巴增强子结合因子-1（LEF-1）之间形成蛋白复合物，该事件导致纤连蛋白和IL-8的合成和分泌。根据我们的初步数据，我们假设在血管生成过程中 PAP2b 在连接内皮细胞的粘附结构的形成和组织中发挥关键作用。其机制包括 PAP2b 形成和组织大分子复合物、与整合素子集相互作用以及通过 LEF-1 转录机制介导纤连蛋白合成的能力。该提案的总体目标是确定 PAP2b 与 p120 连环蛋白相互作用并介导纤连蛋白合成的机制。我们建议通过两个主要具体目标来检验我们的假设：（1）表征PAP2b与p120连环蛋白相互作用的机制，改变LEF转录，并诱导纤连蛋白和IL-8的表达，以及（2）使用Tie-2/Cre系统检查小鼠中条件性删除Pap2b基因的功能后果。使用内皮细胞检查 SiRNA 介导的 PAP2b 下调的后果。我们预计我们的研究将进一步了解内皮 PAP2b 在生理和病理血管生成中的作用。总之，这些研究有望揭示抗血管生成分子治疗的新靶点。