Polymer Carrier for Ischemia-Inducible Gene Therapy

描述（由申请人提供）： 尽管缺血性心脏病（IHD）的治疗取得了进展，但每年仍有超过50万美国人进展为终末期IHD和充血性心力衰竭。基因治疗已成为治疗IHD的一种有前途的选择。使用血管内皮生长因子（VEGF）的基因治疗最近已被证明有助于在动物冠状动脉结扎后保护心肌功能，并有助于在最初的人体试验中缓解心肌缺血症状。然而，基因治疗的广泛适用性仍然存在重大限制。目前的基因递送到心肌的方法受到患者发病率和死亡率的潜在限制，或者受到低转染效率的限制。此外，影响缺血性和非缺血性心肌的IHD的基因治疗与血管瘤形成和动脉粥样硬化斑块进展相关。在基因治疗广泛应用于IHD之前，需要开发安全、有效的基因转染和调控基因表达的技术。我们建议：1）开发两种新的多功能阳离子水溶性脂质聚合物，以实现高水平的靶向基因转染，同时毒性最小; 2）开发IHD的治疗性基因构建体，其表达受心肌内氧张力调节。我们的脂质聚合物含有阳离子DNA缩合剂、亲水性间隔物和疏水性分子。这些聚合物提供良好的溶解性、有效的溶酶体逃逸和有效的摄取。将促红细胞生成素EPO增强子、EPO 3 ′-非翻译区（3 ′-UTR）和氧依赖性降解结构域掺入VEGF基因中，以促进仅在心肌缺血区域中的稳定蛋白质表达。这些基因构建体将使用水溶性脂质聚合物载体递送至心肌。在体外证实高转染效率和缺血诱导基因表达后，我们将在IHD手术模型中测试体内VEGF的调节表达。这些研究将是开发1）临床上有用的载体，用于以最小的毒性有效转染心肌，2）治疗性基因，其表达仅限于心肌缺血区域，有助于使基因治疗在IHD临床上的安全应用成为现实。

DESCRIPTION (provided by applicant): Despite advances in the treatment of ischemic heart disease (IHD), more than 500,000 Americans progress to end-stage IHD and congestive heart failure each year. Gene therapy has emerged as a promising option for the treatment of IHD. Gene therapy using Vascular Endothelial Growth Factor (VEGF) has recently been demonstrated to help preserve myocardial function following coronary artery ligation in animals and to help relieve symptoms of myocardial ischemia in initial human trials. Significant limitations remain, however, to the broad applicability of gene therapy. Current methods of gene delivery to the myocardium are limited by the potential for patient morbidity and mortality or, alternatively, by low transfection efficiency. Further, gene therapy for IHD that affects both ischemic and non-ischemic myocardium is associated with angioma formation and atherosclerotic plaque progression. Before gene therapy can be widely applied to IHD, techniques for safe, efficient gene transfection and regulated gene expression will need to be developed. We propose to: 1) develop two novel multifunctional cationic water-soluble lipopolymers to achieve high levels of targeted gene transfection with minimal toxicity and 2) develop therapeutic gene constructs for IHD whose expression is regulated by oxygen tension within the myocardium. Our lipopolymers contain a cationic DNA condensing agent, a hydrophilic spacer, and a hydrophobic molecule. These polymers offer good solubility, effective lysosomal escape and efficient uptake. The erythropoietin EPO enhancer, the EPO 3'- untranslated region (3'-UTR) and an oxygen dependent degradation domain will be incorporated into the VEGF gene to promote stable protein expression in only ischemic regions of the myocardium. These gene constructs will be delivered to the myocardium using water-soluble lipopolymer carriers. After demonstrating high transfection efficiency and ischemia-inducible gene expression in vitro, we will test the regulated expression of VEGF in vivo in surgical models of IHD. These studies will be integral to the development of 1) a clinically useful vector for efficient transfection of the myocardium with minimal toxicity and 2) therapeutic genes whose expression is limited to ischemic regions of the myocardium, helping to make the safe application of gene therapy for IHD a clinical reality.