Nanotechnology for Treatment of Diabetic Retinopathy

描述（由申请人提供）： 糖尿病视网膜病变（diabetic retinopathy，DR）是糖尿病的常见并发症，也是世界范围内致盲的主要原因之一。糖尿病性黄斑水肿（DME）和视网膜新生血管（NV）是导致DR患者视力丧失的两种主要病理变化。视网膜中血管内皮生长因子（VEGF）的过度表达是DR中血管渗漏的主要致病因素（2-4）。目前，没有令人满意的治疗DME和视网膜NV的疗法，但最肯定的是，存在迫切的需求。 Charlesson，LLC及其全资子公司LifeTrees，LLC是位于俄克拉荷马州的公司，它们正在领导治疗严重眼疾的药物产品的发现和开发。该公司正在开发第一种用于治疗上述疾病的眼药水疗法，并在过去12个月内取得了重要的商业里程碑。Charlesson最近将Atomic Venture Partners的一位创始人兼职加入了其执行管理团队。AVP是一家早期风险投资基金，投资于制药公司，并在硅谷，波士顿和OKC设有办事处。此外，该公司还与俄克拉荷马州大学健康科学中心（OUHSC）建立了强大的研发合作伙伴关系，并与Dean McGee眼科研究所和OK医学研究基金会建立了关系。 新血管形成、糖尿病视网膜病变和黄斑变性治疗的市场规模估计超过90亿美元，每年增长超过20%。糖尿病，包括糖尿病性视网膜病变，正在迅速成为工业化世界的流行病。大约有1820万美国人患有糖尿病，美国每年有270万新病例。糖尿病视网膜病变是20至74岁美国成年人新失明病例的主要原因，每年造成12，000至24，000例新失明病例。 纤溶酶原Kringle 5（K5）是纤溶酶原的蛋白水解片段。它是一种内源性血管生成抑制剂。纤溶酶原含有5个kringle结构域，每个结构域由80个氨基酸组成。血管抑素由纤溶酶原的前4个kringles（K1-4）组成。K5具有比血管抑素更强的抗血管生成活性。我们以前的研究表明，玻璃体内注射K5可以预防氧诱导的视网膜病变（OIR）和链脲佐菌素（STZ）诱导的糖尿病模型中视网膜血管渗漏的发生并阻止其进展。K5注射也有效地改善了OIR模型中的视网膜NV。K5下调培养的视网膜M？ller细胞中VEGF的表达，M？ller细胞是视网膜和OIR大鼠视网膜中VEGF的主要生产者。K5还抑制内皮细胞迁移，这是血管生成中的关键过程。 该I期项目的目标是开发一种新型的非病毒K5基因递送系统，该系统安全，具有很强的组织特异性和K5在视网膜中的长期表达。Müller细胞是VEGF的主要生产者，VEGF是血管通透性和血管生成的有效介质。为了实现组织特异性表达，已经构建了在M？ller细胞特异性启动子（胶质细胞酸性蛋白（GFAP）启动子）控制下的人K5。我们的初步研究已经证明，玻璃体内给予这些GFAP-K5纳米颗粒（GFP-K5-NP）减少了OIR大鼠的视网膜血管渗漏并减弱了视网膜NV。该项目将通过定义1）GFAP-K5-NP是否介导视网膜M？ller细胞中的K5表达来扩展这些研究，2）K5表达是否对降低视网膜VEGF水平和STZ糖尿病动物模型中的血管渗漏具有长期作用，以及在OIR模型中减弱视网膜NV和减少视网膜血管渗漏。因此，在本研究的I期项目中，我们将证明GFAP-K5-NP介导K5的视网膜特异性表达，并对视网膜NV和血管渗漏具有治疗作用。这些研究将为II期非病毒疗法的进一步表征奠定坚实的基础。糖尿病性黄斑水肿（DME）和视网膜新生血管（NV）是导致DR视力下降的主要病理改变。Kringle 5对视网膜血管渗漏和新生血管有较强的抗血管生成作用。我们计划通过结合纳米技术和天然血管生成抑制剂来开发一种非病毒和组织特异性的基因治疗，这可能会减弱血管渗漏和视网膜NV。这些新的纳米颗粒可能具有治疗糖尿病血管并发症的治疗潜力。

DESCRIPTION (provided by applicant): Diabetic retinopathy (DR) is a common complication of diabetes and a leading cause of blindness in the world. Diabetic macular edema (DME) and retinal neovascularization (NV) are the two major pathological alternations leading to vision loss in patients with DR. Over-expression of vascular endothelial growth factor (VEGF) in the retina is a major causative factor for vascular leakage in DR (2-4). Currently, there is no satisfactory therapy to treat DME and retinal NV but most certainly, a dire need exists. Charlesson, LLC and its wholly-owned subsidiary LifeTrees, LLC are Oklahoma City-based companiesthat are leading the discovery and development of drug products to treat severe eye disease. The company is developing the first eyedrop-based therapy for treatment of the aforementioned conditions, and has achieved significant commercial milestones in the past 12 months. Charlesson recently added a founder of Atomic Venture Partners to its executive management team on a part-time basis. AVP is an early-stage VC fund that invests in pharmaceutical companies and has offices in the Silicon Valley, Boston, and OKC. Additionally, the company has a strong R&D partnership with the University of Oklahoma Health Sciences Center (OUHSC), and relationships with the Dean McGee Eye Institute and the OK Medical Research Foundation. The market size for neovascularization, diabetic retinopathy, and macular degeneration treatments is estimated to be greater than $9 billion, growing in excess of 20% per year. Diabetes, including diabetic retinopathy, is quickly becoming an epidemic in the industrialized world. About 18.2 million Americans have diabetes, with 2.7 million new cases in the U.S. each year. All people with diabetes, both type 1 and type 2, are at risk to develop DR. Diabetic retinopathy is the leading cause of new cases of blindness among American adults between 20 and 74 years, causing 12,000 to 24,000 new cases of blindness each year. Plasminogen kringle 5 (K5) is a proteolytic fragment of plasminogen. It is an endogenous angiogenic inhibitor. Plasminogen contains 5 kringle domains, each consisting of 80 amino acids. Angiostatin consists of the first 4 kringles (K1-4) of plasminogen. K5 has a more potent anti-angiogenic activity than angiostatin. Our previous studies have shown that intravitreal injection of K5 prevents the development and arrests the progression of retinal vascular leakage in the oxygen-induced retinopathy (OIR) and streptozotocin (STZ)-induced diabetic models. K5 injection also effectively ameliorates the retinal NV in the OIR model. K5 down-regulates the VEGF expression in cultured retinal M¿ller cells, the major producer of VEGF in the retina and in the retina of OIR rats. K5 also inhibits endothelial cell migration, which is a critical process in angiogenesis. The goal of this phase I project is to develop a novel, non-viral K5 gene delivery system that is safe, has strong tissue specificity and long-term expression of K5 in the retina. The M¿ller cells are the major producer of VEGF which is a potent mediator of vascular permeability and angiogenesis. In order to achieve a tissue-specific expression, human K5 has been constructed under the control of a M¿ller cell-specific promoter, the glial fibrillary acidic protein (GFAP) promoter. Our preliminary study has demonstrated that the intravitreal administration of these GFAP-K5 nanoparticles (GFP-K5-NP) reduces the retinal vascular leakage and atenuates retinal NV in OIR rats. This project will extend these studies by defining 1) if GFAP-K5-NP mediates K5 expression in M¿ller cells in the retina, 2) if the K5 expression has long-term effects on reducing retinal VEGF levels and vascular leakage STZ-diabetic animal models, and attenuates retinal NV and reduces retinal vascular leakage in the OIR model. Therefore, in this phase I project, we will prove the concenpt that the GFAP-K5-NP mediates the retina-specific expression of K5 and has therapeutic effects on retinal NV and vascular leakage. These studies will lay a solid ground for the further characterization of these non-viral therapies in Phase II. Diabetic macular edema (DME) and retinal neovascularization (NV) are the major pathological alternations leading to the vision loss in DR. Kringle 5 has potent anti-angiogenic effect on retinal vascular leakge and neovascularization. We plan to develop a non-viral and tissue specific gene therapy by combining the nanotechnology and natural angiogenic inhibitors, which may attenuate vascular leakage and retinal NV. These novel nanoprticles may have the therapeutic potential in the treatment of diabetic vascular complications.