MODIFIED POLY(DISULFIDE AMINE)AS A PANCREAS TARGETING POLYMERIC VECTOR

描述(申请人提供)：最近，由于临床试验中病毒载体的安全性问题和有害不良事件的增加，非病毒基因治疗继续引起人们的关注。这项应用的目标是设计一种功能性的、以胰腺为靶点的聚合基因载体，以携带用于有效的1型糖尿病基因治疗的治疗性质粒DNA。提出了一种新型的基于聚二硫胺的可生物降解聚合物载体S。与传统的高相对分子质量聚乙烯亚胺相比，多(二硫胺)S具有更高的转染率和更低的细胞毒性。这些可生物降解和生物相容的多(二硫胺)基因载体将通过含有胰腺特异性靶向配基的聚乙二醇偶联物进行修饰，以实现主动靶向。使用聚乙二醇有两个方面，一是首先提供冠状肾上腺素，二是静脉给药后的复合稳定性。1型糖尿病是一种致命的疾病，有许多有害和致命的后遗症；然而，多年的机制研究尚未提供明确的致病机理了解。据报道，NKG2D介导的胰岛2细胞死亡在1型糖尿病的发病机制中起重要作用。最近的报道表明，肿瘤通过分泌受体NKG2D的可溶性配体来防止宿主免疫系统的攻击，NKG2D在几个激活的淋巴细胞中表达。肿瘤的这种伪装能力会导致淋巴细胞细胞间接触介导的杀细胞活性降低。因此，利用这种肿瘤模型行为，我们假设胰岛2细胞分泌NKG2的这种可溶性配体sRAE-1，将保护胰岛免受自身免疫淋巴细胞的伤害。结合以肾上腺素为靶点的多(二硫胺)基因载体进入胰腺，我们假设胰腺特异的大鼠胰岛素启动子(RIP)将对sRAE-1的表达提供更严格的空间和时间控制。为了增强sRAE-1的转录，将使用两步转录扩增(TSTA)。这一治疗1型糖尿病的新方法将在体外和体内通过1型糖尿病非肥胖(NOD)小鼠进行评估。

DESCRIPTION (provided by applicant): Recently, non-viral gene therapy continues to attract much attention due to increasing safety concerns and deleterious adverse events of viral vectors in clinical trials. The goal of this application is to design a functional, pancreas-targeting polymeric gene carrier to carry therapeutic plasmid DNAs for efficient type-1 diabetes gene therapy. A new class of biodegradable polymeric carriers based on poly(disulfide amine)s are proposed. Poly(disulfide amine)s have demonstrated higher transfection efficiency with much lower cytotoxicity compared to conventional high molecular weight polyethylenimine. These biodegradable and biocompatible poly(disulfide amine) gene carriers will be modified for active targeting by PEG conjugation bearing ephrine, a pancreas-specific targeting ligand. The use of PEG is two-fold to first provide coronal ephrine presentation and for polyplex stability following intravenous administration. Type-1 diabetes is a deadly disease with numerous deleterious and deadly sequelae; yet, years of mechanistic research has yet to provide a clear pathogenic understanding. It is reported that NKG2D-mediated death of islet 2-cells plays an important role in the pathogenesis of type-1 diabetes. Recent reports demonstrate that tumors prevent attack by the host immune system by secreting soluble ligands for the receptor, NKG2D, expressed in several activated lymphocytes. This ability of tumors to disguise itself leads to reduced cell-cell contact-mediated cytocidal activity of the lymphocytes. Hence, exploiting this tumor model behavior we hypothesize that islet 2-cells secreting this soluble ligand for NKG2, sRAE-1, will protect pancreatic islets from autoimmune lymphocytes. In conjunction with ephrine-targeted poly(disulfide amine) gene carriers to the pancreas, we hypothesize that a pancreas-specific rat insulin promoter (RIP) will provide even tighter spatial and temporal control over sRAE-1 expression. To enhance transcription of sRAE-1, a two-step transcriptional amplification (TSTA) will be used. This novel approach to treat type-1 diabetes will be evaluated in vitro and in vivo with type-1 diabetic, non-obese (NOD) mice.