Targeted therapy in Type 1 diabetes

描述(由申请人提供)：由于1型糖尿病(T1D)的复杂性，成功的治疗将需要一种范式转换的多学科方法。新靶点的发现、高效药物输送系统的开发以及最先进的成像技术的集成，将提供对药物输送和治疗结果的实时监测。传统疗法无效的部分原因是缺乏针对胰岛的定向靶向，导致生物利用度低。这种低效的传递需要系统地给予大剂量的治疗，从而产生不良的非靶向效应和毒性。为了克服这些严重的限制，我们建议开发具有成像能力的高效递送系统，专门将基于siRNA的治疗定向到产生胰岛素的β细胞。我们的定向治疗策略是基于RNAi在沉默有害致病基因方面的精妙特异性，以及我们在开发图像引导系统在各种环境中传递siRNA方面的丰富经验。在这里，我们建议开发一种图像辅助的方法，使用基于葡聚糖包被的氧化铁纳米颗粒的靶向磁性纳米颗粒平台(Nanodrug，ND)将siRNA疗法输送到内源性β细胞。它们将作为载体，通过靶向最近发现的β细胞上的标记(ND-siRNA)，将siRNA特异性地输送到胰腺β细胞。此外，这些纳米颗粒将作为成像记者，通过光学和磁共振成像(MRI)在体内监测递送。我们将首先产生针对β细胞的荧光素酶(Luc)结合的β细胞特异性部分，并利用生物发光成像(BLI)来检测其在 活体标记β细胞的能力。接下来，我们将把选定的靶向部分连接到含有siRNA的磁性纳米颗粒上，并测试它们将siRNA运送到培养中的孤立胰岛的能力，然后在T1D动物模型中同时进行体内监测。负责β细胞凋亡和免疫识别的基因将成为siRNA的靶点。我们期望在预防研究中观察到T1D发病率的降低，并在逆转研究中观察到恢复正常血糖的动物数量增加。

DESCRIPTION (provided by applicant): Due to the complexity of type 1 diabetes mellitus (T1D), successful treatment will require a paradigm shifting multidisciplinary approach. The discovery of novel targets, the development of efficient drug delivery systems and the integration of state-of-the-art imaging techniques will provide real-time monitoring of both drug delivery and therapeutic outcome. Conventional therapeutics are ineffective due, in part, to the lack of directed targeting to the islets, resulting in low bioavailability. This inefficient delivey necessitates systemic administration of high doses of therapy and consequently untoward off-target effects and toxicity. To overcome these severe limitations, we propose to develop efficient delivery systems with imaging capabilities that specifically direct siRNA-based therapies to insulin-producing beta-cells. Our strategy for directed therapy is based on the exquisite specificity of RNAi for silencing harmful disease-promoting genes and our extensive experience in developing image-guided systems for siRNA delivery in various settings. Here we propose to develop an image-assisted approach for delivering siRNA therapy to endogenous beta- cells using a targeted magnetic nanoparticle platform (Nanodrug, ND) based on dextran coated iron oxide nanoparticles. These will serve as vehicles for specific delivery of siRNA to pancreatic beta-cells by targeting recently identified markers on beta-cells (ND-siRNA). In addition, these nanodrugs will function as imaging reporters for in vivo monitoring of delivery by optical and magnetic resonance imaging (MRI). We will first generate luciferase (luc)-conjugated beta-cell-specific moieties that target beta-cells and utilize bioluminescence imaging (BLI) to test their in vivo ability to label beta-cells. Next, we will attach selected targeting moieties to siRNA-containing magnetic nanoparticles and test their ability to deliver siRNA to isolated islets in culture and then in animal models of T1D concurrently with in vivo monitoring of delivery. Genes that are responsible for beta-cell apoptosis and immune recognition will be targeted with siRNA. We expect to observe a decreased T1D incidence in prevention studies and increased number of animals with restored normoglycemia in reversal studies.