Regulation of Expression of Secreted Flt-1

分泌型 Flt-1 表达的调节

• 批准号: 6720964
• 负责人: WILLIAM R HUCKLE
• 金额: $ 14.49万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6720964
• 关键词: DNA binding protein; angiogenesis; biological models; biological signal transduction; blood vessels; cell free system; cell growth regulation; cell surface receptors; chemical stability; developmental genetics; embryology; enzyme activity; gene induction /repression; laboratory mouse; messenger RNA; phorbols; polymerase chain reaction; posttranscriptional RNA processing; posttranslational modifications; protein kinase C; protein quantitation /detection; receptor expression; secretion; transcription factor; vascular endothelial growth factors

DESCRIPTION (provided by applicant): Vascular endothelial growth factor (VEGF) is a major mediator of neovascularization in embryonic development and adult vascular homeostasis. VEGF contributes to adaptive angiogenesis in ischemic tissue as well as excessive vessel formation in proliferative vascular pathologies. VEGF and its signaling pathways thus may provide a means of either promoting angiogenesis in vascular insufficiency or inhibiting angiogenesis in diabetic retinopathy or in tumors. Responses to VEGF are mediated by two endothelial cell-surface receptors, Fit-1 and KDR. An RNA processing variant of Fit-1 mRNA produces a secreted form of Fit-1 ("sFIt-1 ") that binds VEGF with high affinity and can inhibit biological responses to VEGF. Previous studies indicate that the ratio of sFIt-l:FIt-1 can vary under physiological conditions, suggesting that molecular mechanisms exist to specifically control the mRNA processing events leading to sFIt-l. We postulate that the relative expression of sFIt-1 and Fit-1 is a significant biological determinant of vascular responsiveness to VEGF. The goals of the proposed research are to identify new experimental systems and biochemical assays to discover the regulatory mechanisms governing sFIt-1 expression. Our specific aims are 1) to identify biological models appropriate for the study of regulated sFIt-1 expression, 2) to identify nuclear factors involved in Fit-1 pre-mRNA processing, and 3) to determine the post-transcriptional mechanism by which protein kinase C activation alters sFIt-1 expression. In Aim 1, we will quantify sFIt-1:Fit-1 expression in cell- or animal-based models of vascular development and adult angiogenesis. Under Aim 2, we will probe the interaction of specific and unknown processing factors with Fit-1 pre-mRNA using cell-free systems. In Aim 3, we will assess the role of altered mRNA stability and pre-mRNA 3rocessing in the induction of sFIt-1 expression by phorbol ester. These studies will increase our understanding of the mechanisms of both adaptive and therapeutic angiogenesis, and may provide rationale for developing novel pharmacological interventions to modulate sFlt-1 expression and, thereby, VEGF responsiveness.

描述（由申请人提供）：血管内皮生长因子（VEGF）是胚胎发育和成人血管稳态中新血管形成的主要介质。VEGF有助于缺血组织中的适应性血管生成以及增生性血管病变中的过度血管形成。因此，VEGF及其信号通路可能在血管功能不全中促进血管生成，或在糖尿病视网膜病变或肿瘤中抑制血管生成。对VEGF的反应是由两种内皮细胞表面受体fit1和KDR介导的。Fit-1 mRNA的RNA加工变体产生一种分泌形式的Fit-1（“sFIt-1”），其高亲和力结合VEGF并可以抑制对VEGF的生物反应。先前的研究表明，在生理条件下，sfit -1:FIt-1的比例会发生变化，这表明存在特异性控制导致sfit -1的mRNA加工事件的分子机制。我们假设fit1和fit1的相对表达是血管对VEGF反应性的重要生物学决定因素。提出的研究目标是确定新的实验系统和生化分析，以发现控制sfit1表达的调节机制。我们的具体目标是1)确定适合研究受调节的sFIt-1表达的生物学模型，2)确定参与Fit-1前mrna加工的核因子，以及3)确定蛋白激酶C激活改变sFIt-1表达的转录后机制。在Aim 1中，我们将量化基于细胞或动物的血管发育和成人血管生成模型中的fit1: fit1表达。在Aim 2中，我们将使用无细胞系统探索特定和未知加工因子与Fit-1 pre-mRNA的相互作用。在Aim 3中，我们将评估mRNA稳定性的改变和mRNA前3加工在phorbol酯诱导sFIt-1表达中的作用。这些研究将增加我们对适应性和治疗性血管生成机制的理解，并可能为开发新的药物干预来调节sFlt-1的表达，从而调节VEGF的反应性提供理论依据。