Inhibition of CNV using a transgenic PEDF model

描述（由申请人提供）：年龄相关性黄斑变性（AMD）是美国老年人失明的主要原因。脉络膜新生血管（CNV）是AMD严重视力丧失的主要原因。随着脉络膜新生血管治疗新方法的出现，体内方法不仅需要评估疗效，还需要解决临床试验的重要问题（例如，剂量，毒性）。因此，我们建议使用可诱导的转基因小鼠模型作为研究CNV抑制的创新方法。具体来说，我们建议研究色素上皮衍生因子（PEDF）的作用，PEDF是一种有效的血管生成抑制剂，对角膜、视网膜和脉络膜新生血管有显著的抑制作用。我们的长期目标是发展PEDF作为预防和治疗脉络膜新生血管的一种治疗方式。我们推测，除了抑制CNV的形成外，PEDF还可以导致现有脉络膜新生血管的退化。因此，我们提出以下具体目标：(1)建立具有视网膜特异性、可诱导表达PEDF的转基因PEDF小鼠模型。目的1将包括小鼠模型中诱导PEDF的空间、时间和定量表达的表征。(2)利用激光诱导CNV模型确定PEDF作为脉络膜新生血管治疗剂的潜力。目的2将确定转基因PEDF表达是否可以阻止脉络膜新生血管以及导致现有CNV的回归。此外，Aim 2将讨论预防CNV所需的PEDF剂量要求，以及预防所需的PEDF存在时间。最后，Aim 2将确定转基因PEDF表达是否会导致体内脉络膜内皮细胞凋亡。在我们的研究中，我们将采用四环素诱导的基因表达系统来诱导PEDF的光受体特异性表达。我们将研究转基因PEDF在小鼠体内表达对激光诱导脉络膜新生血管的影响。预计我们的建议将为进一步研究发展基金的行动机制提供坚实的基础。此外，我们的研究将为CNV候选抑制剂的研究提供新的实验方法，提供关于疗效、治疗剂量、给药频率和毒性的重要数据。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly in the United States. Choroidal neovascularization (CNV) is largely responsible for severe vision loss from AMD. As new and promising treatments emerge for the treatment of choroidal neovascularization, in vivo approaches will be needed not only to evaluate efficacy, but also to address issues important for clinical trials (e.g., dosing, toxicity). We thereby propose to use an inducible transgenic mouse model as an innovative approach to the study of inhibition of CNV. Specifically, we propose to study the effects of pigment epithelium-derived factor (PEDF), which has emerged as a potent inhibitor of angiogenesis, with dramatic inhibitory effects on corneal, retinal, and choroidal neovascularization. Our long-term oal is to develop PEDF as a ther~eutic modality for the prevention as well as treatment of choroidal neovascularization. We hyaothesize that PEDF can cause regression of existing choroidal neovascularization, in addition to inhibiting CNV formation. Accordingly, we propose the following Specific Aims: (1) Develop a transgenic PEDF mouse model with retina-specific, inducible expression of PEDF. Aim 1 will include the characterization of spatial, temporal, and quantitative expression of induced PEDF in the mouse model. (2) Define the potential of PEDF as a therapeutic agent for choroidal neovascularization using the laser-induced CNV model. Aim 2 will determine if transgenic PEDF expression can prevent choroidal neovascularization as well as cause regression of existing CNV. In addition, Aim 2 will address the PEDF dosage requirements required for prevention of CNV, as well as the duration of PEDF presence necessary for prevention. Finally, Aim 2 will determine if transgenic PEDF expression causes choroidal endothelial cell apoptosis in vivo. In our studies, we will adapt the tetracycline-inducible gene expression system to induce photoreceptor-specific expression of PEDF. We will study the effects of transgenic PEDF expression in mice on laser-induced choroidal neovascularization. It is anticipated that our proposal will provide a strong foundation for further studies regarding the mechanism of PEDF action. In addition, our studies will provide a new experimental approach for the study of candidate inhibitors of CNV, providing important data regarding efficacy, therapeutic dose, frequency of administration, and toxicity.