The Oxygen Sensing Mechanism in Retinal Endothelial Cells as a Novel Target to Suppress Ischemic Neovascularization

视网膜内皮细胞的氧传感机制作为抑制缺血性新生血管的新靶点

基本信息

批准号：
10653006
负责人：
Guo-Hua Fong
金额：
$ 60.67万
依托单位：
UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10653006
关键词：
Adult Affect American Angiogenesis Inhibition Angiogenesis Inhibitors Angiogenic Factor Antibodies Antibody Therapy Apoptosis Astrocytes Binding Biochemical Biological Availability Blindness Blood Blood Vessels Brain Hypoxia-Ischemia Cell Proliferation Cells Data Development Endothelial Cells Endothelium Extravasation Genetic Transcription Growth Hepatocyte Hydroxylation Hypoxia Hypoxia Inducible Factor Injections Innovative Therapy Ischemia Lentivirus Vector Literature Location Mediating Membrane Mitogens Modeling Molecular Mus Mutation Oxygen Paracrine Communication Pathologic Pathologic Neovascularization Patients Phenotype Point Mutation Polyubiquitination Procollagen-Proline Dioxygenase Proteins Proxy Publishing Refractory Regulatory Element Resistance Response Elements Retina Retinal Detachment Retinal Diseases Retinal Neovascularization Retinopathy of Prematurity Site Small Interfering RNA Testing Tissues Traction VEGFA gene Vascular Endothelial Growth Factor Receptor-1 Vision angiogenesis antiangiogenesis therapy bevacizumab design experimental study improved insight keratinocyte mouse model neovascular neovascularization novel novel strategies novel therapeutic intervention overexpression paracrine postnatal proliferative diabetic retinopathy receptor response retinal angiogenesis retinal ischemia retinal neuron scaffold side effect tissue oxygenation vector

项目摘要

Project Summary Proliferative diabetic retinopathy (PDR) is a leading cause of blindness in adults, mostly due to neovascularization in ischemic and hypoxic retinal tissues. While monthly injection of anti-VEGF provides relief, it is associated with major side effect such as retinal detachment, and over a third of the patients are refractory to the antibody treatment. The long term objective of this project is to investigate how the endothelial oxygen sensing mechanism regulates retinal angiogenesis, and develop novel strategies to curb neovascularization in ischemic retinal tissues. Typically, hypoxia drives angiogenesis by paracrine mechanisms wherein hypoxia- inducible factor-α proteins upregulate the expression of angiogenic factors, which activate their cognate receptors on nearby endothelial cells (EC). In well oxygenated tissues, HIF-α proteins degrade rapidly following oxygen dependent prolyl hydroxylation by prolyl hydroxylase domain containing proteins (PHD1, PHD2, and PHD3). Thus, deficiency in PHDs mimics hypoxia at the molecular level by allowing HIF-α proteins to accumulate. Indeed, our published studies demonstrate that post-natal PHD2 deficiency globally or in non- endothelial cells promotes vascular growth or survival. In recent Preliminary Studies, we made a rather unexpected observation that EC specific PHD2 deficiency (Phd2EC-/-) inhibited instead of promoting retinal vascular development, despite high level accumulation of HIF-1α and HIF-2α. On the other hand, Flt-1 was upregulated, which is known to sequester VEGF-A. In the mouse model of oxygen-induced retinopathy (OIR), a proxy of PDR as well as ROP (retinopathy of prematurity), Phd2EC-/- mice also displayed greatly reduced neovascularization. These findings led to our Central Hypothesis stating that retinal angiogenesis is dynamically regulated by two opposing oxygen sensing mechanisms: in the cells of the retinal parenchyma, hypoxia activates angiogenesis by HIF- dependent expression of angiogenic factors; whereas in the retinal ECs, hypoxia inhibits angiogenesis by upregulating anti-angiogenic molecules such as Flt-1. Aim 1. Investigate how the endothelial oxygen sensing mechanism regulates retinal vascular development. Examine whether EC specific deletion of HIF-1α, HIF-2α, or Flt-1 rescues retinal vascular development in Phd2EC-/- mice; whether the accumulation of oxygen resistant but otherwise normal HIF-1α and HIF-2α suppresses angiogenesis; and whether HIF-1α and HIF-2α directly interact with Flt-1 regulatory elements; Aim 2. Investigate whether the oxygen sensing mechanisms regulating developmental angiogenesis also operate during ischemic neovascularization in the OIR model. Aim 3. Test lentiviral vector-mediated anti-angiogenesis strategies. Lentiviral vectors will be constructed that express PHD siRNAs or membrane - anchored truncated Flt-1 (tFlt-1), all spatially restricted to retinal ECs and likely further restricted to ECs in ischemic retinal locations. The ability of these vectors to suppress ischemic retinal neovascularization will be evaluated in the OIR model. These studies may potentially lead to an innovative therapy to suppress neovascularization associated with PDR.

项目摘要增殖性糖尿病性视网膜病（PDR）是成年人失明的主要原因，主要是由于缺血性和低氧性视网膜组织中的新血管化。它与主要副作用（例如视网膜脱离）有关，超过三分之一的患者是难治性的抗体处理。传感机制调节视网膜血管生成，并制定新颖的新型策略来抑制新血管缺血性视网膜组织。诱导因子-α蛋白上调血管生成因子的表达，激活其同源附近的原子细胞上的受体（EC）。遵循氧气依赖性羟基羟基化羟化酶域蛋白（PHD1，PHD1， PHD2和PHD3）。实际上，我们已发表的研究证明内皮细胞促进了血管生长或生存。意外的观察到EC特异性PHD2缺乏症（PHD2EC - / - ）抑制而不是促进视网膜尽管HIF-1α和HIF-2α的高度积累，但flt-1战争还是flt-1战争，但血管发展上调，已知在氧气诱导的小鼠模型中隔离VEGF-A， PDR和ROP的代理（预先病变），PHD2EC - / - 小鼠也大大减少了这些发现导致我们通过两个相对的氧气感应机制动态定制：在视网膜实质的细胞中，缺氧通过血管生成因子的HIF表达激活血管生成。 ECS缺氧通过上调抗血管生成分子（例如FLT-1）来抑制血管生成内皮氧气传感机制如何定于视网膜血管发育。 HIF-1α，HIF-2α或FLT-1的规范挽救了PHD2EC - / - 小鼠的视网膜血管发育；耐氧但正常的HIF-1α和HIF-2α的积累会抑制血管生成。 HIF-1α和HIF-2α是否直接与FLT-1调节元件相互作用；调节发育血管生成的氧气传感机制在缺血性期间也起作用 OIR模型中的新血管化。将构建慢病毒载体，以表达博士学位siRNA或膜锚定的截短FLT-1（TFLT-1），所有空间上都限于视网膜EC，并可能进一步限制在缺血性视网膜位置。这些向抑制缺血性视网膜新血管形成的载体将在OIR模型中评估。研究可能会导致致命的抑制与PDR相关的新血管形成。