siRNA Protection of Islet Grafts in Baboons

狒狒胰岛移植物的 siRNA 保护

基本信息

批准号：
9285782
负责人：
ANNA MOORE
金额：
$ 39.71万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-07-01 至 2017-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9285782
关键词：
Adverse effects Allogenic Animals Apoptosis Biochemistry Biopsy Specimen Blood CASP3 gene CASP8 gene Cessation of life Chemicals Dose Effectiveness Evaluation Experimental Designs Gene Silencing Genes Histology Hormones Immune Immunocompetent Immunosuppression Immunosuppressive Agents In Vitro Incubated Infection Insulin Insulin-Dependent Diabetes Mellitus Islet Cell Islets of Langerhans Islets of Langerhans Transplantation Kidney Label Longevity Magnetic Resonance Imaging Magnetic nanoparticles Magnetism Malignant Neoplasms Messenger RNA Modeling Monitor Outcome Papio Patients Pharmaceutical Preparations Phenotype Procedures Protocols documentation RNA Interference Regimen Reporter Resistance Reverse Transcriptase Polymerase Chain Reaction Rodent Site Small Interfering RNA Techniques Time Toxic effect Transplantation Western Blotting autoreactivity base design diabetic dosage improved in vitro testing in vivo intrahepatic iron oxide islet knock-down nanoparticle non-diabetic nonhuman primate pre-clinical public health relevance therapeutic gene

项目摘要

DESCRIPTION (provided by applicant): Pancreatic islet transplantation (Tx) has a lifesaving potential for Type 1 diabetes patients. However, even with introduction of the immunosuppressive regimen known as Edmonton Protocol, insulin independence was only transient in most recipients due to significant islet loss that starts early after the procedure. Allogeneic immune rejection, one of the major reasons for islet death, requires permanent use of immunosuppressive drugs, which are toxic to islets and cause serious side effects including cancer and infection. Moreover, in addition to its significant short and long-term side effects, there is direct evidence that immunosuppression leads to reemergence of autoreactivity, the condition that Tx is supposed to treat. New strategies to reduce the dose of immunosuppression by providing alternative defense approaches to transplanted islets are urgently needed. RNA interference is a technique that offers great potential for therapeutic gene silencing and could be employed for improving islet graft resistance to damaging factors after transplantation. We have previously demonstrated the utility of siRNA-conjugated iron oxide-based magnetic nanoparticle (MN) probes for siRNA delivery to pancreatic islets prior to transplantation in immunodeficient rodents. siRNA directed towards genes responsible for islet damage silenced these genes and provided islet protection prior to transplantation. By the use of a magnetic reporter, labeled pancreatic islets could be monitored after transplantation by in vivo magnetic resonance imaging (MRI). These preliminary studies in rodents showed significant improvement in graft outcome after the silencing of genes responsible for apoptosis and immune rejection. In this application we propose to extend these studies to the next level and investigate the effectiveness of MN-siRNA in a pre- clinical immunocompetent non-human primate model of islet transplantation. The experimental design will include synthesis of the MN-siRNA probes targeting caspase-3, caspase-8, Fas and beta2-microglobulin genes, which will then be incubated with pancreatic islets. This will lead to mRNA silencing and simultaneous magnetic labeling of islet cells. Allogeneic islets pre-incubated with these MN-siRNA probe(s) will be transplanted into diabetic baboons that will be monitored long-term using magnetic resonance imaging while tapering immunosupression. In vivo MRI will allow us to follow graft outcome and compare it with non- manipulated control grafts. We anticipate that siRNA treatment of the islets will allow for significant improvement in long-term graft outcome and reduction of the effective dose of immunosupressants. Due to the module design of the nanoparticles siRNA molecules to additional targets can be introduced if necessary.

描述（由申请人提供）：胰岛移植 (Tx) 对于 1 型糖尿病患者具有挽救生命的潜力。然而，即使引入了称为埃德蒙顿方案的免疫抑制方案，由于显着的胰岛损失，大多数接受者的胰岛素依赖也只是暂时的。手术后早期开始的同种异体免疫排斥是胰岛死亡的主要原因之一，需要永久使用免疫抑制药物，这些药物对胰岛有毒并导致严重的副作用，包括此外，除了显着的短期和长期副作用外，有直接证据表明免疫抑制会导致自身反应性的重新出现，而 Tx 应该通过提供新的策略来减少免疫抑制的剂量。迫切需要针对移植胰岛的替代防御方法，RNA干扰是一种为治疗性基因沉默提供巨大潜力的技术。我们之前已经证明了基于 siRNA 的氧化铁磁性纳米颗粒 (MN) 探针在针对免疫缺陷啮齿动物的 siRNA 接合之前将 siRNA 递送至胰岛的用途。胰岛损伤使这些基因沉默，并在移植前提供胰岛保护。通过使用磁性报告基因，可以在移植后通过体内磁共振成像监测标记的胰岛。 (MRI)。这些在啮齿类动物中的初步研究表明，在沉默负责细胞凋亡和免疫排斥的基因后，移植结果显着改善。在本申请中，我们建议将这些研究扩展到下一个水平，并研究 MN-siRNA 在移植中的有效性。临床前免疫活性非人灵长类胰岛移植模型将包括合成针对 caspase-3、caspase-8、Fas 和 beta2-微球蛋白基因的 MN-siRNA 探针。然后与胰岛一起孵育，这将导致胰岛细胞的 mRNA 沉默并同时进行磁性标记。用这些 MN-siRNA 探针预孵育的同种异体胰岛将被移植到糖尿病狒狒中，并使用磁性对其进行长期监测。体内 MRI 将使我们能够跟踪移植结果并将其与非操作对照移植物进行比较，我们预计 siRNA 治疗胰岛将获得显着效果。由于纳米粒子的模块设计，可以在必要时引入针对其他靶点的 siRNA 分子，从而改善长期移植结果并减少免疫抑制剂的有效剂量。