Targeting the IGF-1 System in Retinal Angiogenesis

靶向视网膜血管生成中的 IGF-1 系统

• 批准号: 6686377
• 负责人: Maria Bartolomeo Grant
• 金额: $ 32.68万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-08-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6686377
• 关键词: Targeting; IGF; System; Retinal; Angiogenesis

DESCRIPTION (provided by applicant): Retinal neovascularization is associated with proliferative diabetic retinopathy and retinopathy of prematurity. Clinical studies suggest that insulin like growth factor-1 (IGF-1) is involved in both diseases and has direct effects on retinal vasculature. To understand the mechanisms by which IGF-1 contributes to normal and abnormal vascular physiology, several processes must be understood in greater detail. This includes how IGF-1 receptor (IGF-1R) expression affects both normal and abnormal retinal vascular growth and how expression of IGF binding protein-3 (IGFBP-3) mediates IGF-1 bioavailability and influences endothelial cell behavior. Of the seven known IGFBPs, IGFBP-3 is the primary carrier of IGF-1 in the serum and its direct apoptotic effects have been demonstrated in numerous cells systems including tumor cells. These apoptotic effects of IGFBP-3 are independent of its ability to bind IGF-1. This proposal focuses on manipulating IGF-1R and IGFBP-3 expression to examine their effects on aberrant vascularization of the retina. We will test the following hypothesis: Decreasing the expression of IGF-1R and increasing the secretion of soluble IGFBP-3 will result in the inhibition of retinal neovascularization though the induction of endothelial cell apoptosis. In Aim 1, we will synthesize IGF-1R mRNA-specific hammerhead ribozymes, infect human retinal endothelial cells with these ribozymes, and characterize ribozyme effects on IGF-1R expression. We will characterize the apoptotic pathways activated by IGFBP-3 and evaluate the action of endogenously produced IGFBP-3 (to induce apoptosis directly) in HREC; the effects of the combined effect of the IGF-1R inhibition with overexpression of IGFBP-3 on HREC apoptosis will also be examined. In Aim 2, we will package our IGF-1R ribozyme into adeno-associated virus (AAV) for site directed expression. A cell cycle/proliferating endothelial cell-specific promoter will drive expression of the IGF-1R ribozymes. These AAV-packaged constructs will be used to inhibit retinal and pre-retinal neovascularization specifically in two mouse models: the mouse pup model of oxygen-induced retinopathy and an adult mouse model that we have developed. In Aim 3, we will express IGFBP-3 using a rAAV protein expression vector and test it in the two mouse models described in Aim 2. We will combine the AAV-IGF-1R ribozymes with AAV-IGFBP-3 to determine if additional inhibition of proliferation and apoptosis occurs. Targeting the IGF-IR and IGFBP-3 in this manner will provide a tool for understanding the role of the IGF-1 system in retinal vascular growth and may provide novel ways to inhibit retinal angiogenesis.

描述（由申请人提供）：视网膜新生血管与增殖性糖尿病视网膜病变和早产儿视网膜病变相关。临床研究表明，胰岛素样生长因子-1（IGF-1）参与了这两种疾病，并对视网膜血管系统有直接影响。为了了解IGF-1促进正常和异常血管生理的机制，必须更详细地了解几个过程。这包括IGF-1受体（IGF-1 R）的表达如何影响正常和异常的视网膜血管生长，以及IGF结合蛋白-3（IGFBP-3）的表达如何介导IGF-1的生物利用度并影响内皮细胞行为。在七种已知的IGFBP中，IGFBP-3是血清中IGF-1的主要载体，其直接的凋亡作用已在包括肿瘤细胞在内的许多细胞系统中得到证实。IGFBP-3的这些凋亡作用与其结合IGF-1的能力无关。该提案的重点是操纵IGF-1 R和IGFBP-3的表达，以检查其对视网膜异常血管化的影响。我们将验证以下假设：降低IGF-1 R的表达，增加可溶性IGFBP-3的分泌，通过诱导内皮细胞凋亡来抑制视网膜新生血管的形成。目的一：合成特异性的锤头状核酶，感染人视网膜内皮细胞，研究核酶对IGF-1 R表达的影响。我们将表征IGFBP-3激活的凋亡途径，并评估内源性产生的IGFBP-3（直接诱导细胞凋亡）在HREC中的作用;还将检查IGF-1 R抑制与IGFBP-3过表达对HREC细胞凋亡的联合作用。目的二：将IGF-1 R核酶包装入腺相关病毒（AAV）中进行定点表达。细胞周期/增殖内皮细胞特异性启动子将驱动IGF-1 R核酶的表达。这些AAV包装的构建体将用于在两种小鼠模型中特异性地抑制视网膜和视网膜前新生血管形成：氧诱导的视网膜病变的小鼠幼仔模型和我们已经开发的成年小鼠模型。在目标3中，我们将使用rAAV蛋白表达载体表达IGFBP-3，并在目标2中描述的两种小鼠模型中对其进行测试。我们将联合收割机将AAV-IGF-1 R核酶与AAV-IGFBP-3组合以确定是否发生增殖和凋亡的额外抑制。以这种方式靶向IGF-IR和IGFBP-3将为理解IGF-1系统在视网膜血管生长中的作用提供工具，并可能提供抑制视网膜血管生成的新方法。