Gene Therapy for Urea Cycle Disorders

尿素循环障碍的基因治疗

• 批准号: 7943736
• 负责人: James M Wilson
• 金额: $ 21.81万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7943736
• 关键词: Address; Adenovirus Vector; Adoptive Transfer; Affect; Animals; Antigen Presentation; Antigen-Presenting Cells; Antigens; Capsid; Chronic; Chronic Hepatitis; Clinical; Clinical Trials Design; Cytotoxic T-Lymphocytes; Dependovirus; Development; Disease; Dose; Down-Regulation; Exposure to; Funding; Gene Transfer; Generations; Genome; Hepatitis; Hepatitis B Virus; Hepatocyte; Immune; Immune response; Infection; Inflammation; Inflammatory; Inherited; Injection of therapeutic agent; LacZ Genes; Ligands; Liver; MHC Class I Genes; Mediating; Minority; Modeling; Mus; Natural Immunity; Outcome; Performance; Play; Principal Investigator; Relative (related person); Request for Applications; Research Personnel; Resistance; Role; SCID Mice; Safety; Schedule; Series; Signal Transduction; Splenocyte; T-Cell Activation; T-Lymphocyte; TLR4 gene; Time; TimeLine; Toll-like receptors; Toxic effect; Transgenes; Transgenic Organisms; Up-Regulation; adeno-associated viral vector; base; candidate selection; cytokine; expression vector; gene therapy; improved; killings; mouse model; perforin; programs; promoter; receptor; transgene expression; urea cycle; vector; vector genome

DESCRIPTION (Provided by Applicant): This application requests two years of revised support for Project I of a program project entitled "Gene Therapy for Urea Cycle Disorders" which is in its second year of funding. All three projects of the P0I have been productive in advancing the aims of the application and remain on schedule according to the original timelines. Specific Aim 3 of Project I was to evaluate the role of inflammation in the performance of AAV vectors. The hypothesis was that a critical step in rendering AAV-transduced hepatocytes susceptible to killing by cytotoxic T lymphocytes (CTLs) was up-regulation of MHC class I and improved presentation of antigen. A series of adoptive transfer studies did confirm this hypothesis. Transfer of lacZ-specific CTLs into mice whose livers were transduced with AAV-LacZ failed to clear transgene expression unless the animals were treated with ligands for Toll-like receptors (TLRs) at the time of the adoptive transfer; under these conditions there was complete loss of transgene expression and clearance of the vector genome concurrent with up-regulation of MHC class I. The investigators recently extended these studies beyond the scope of the program to evaluate the possibility that innate immunity may be sufficient to extinguish transgene expression independent of capsid or transgene T cells. In fact, they showed that injection of low doses of an adenoviral vector expressing an irrelevant transgene with TLR ligands two weeks subsequent to AAV gene transfer was sufficient to completely abolish AAV-encoded transgene expression; vector genomes were diminished but not eliminated, suggesting transcriptional shut off may play a role as well as partial destabilization of the vector genome. The revision aims to further evaluate the role of inflammation in inhibiting transgene expression from AAV vectors in liver. The revised Specific Aim 1 will evaluate a number of important questions regarding the investigators' recent observation, including: Does the low dose Ad contribute through the generation of CTLs or via direct activation of APCs? Do the TLR ligands contribute through engagement of their cognate receptors? Are pro-inflammatory cytokines necessary and/or sufficient? And finally, what is the relative role of signaling via the hepatocyte versus resident APCs? The revised Specific Aim 2 will utilize a mouse model to evaluate the impact of chronic hepatitis infection on AAV vector performance when hepatitis is present at the time of gene transfer or subsequent to gene transfer. RELEVANCE: Adeno-associated viruses hold promise for liver-directed gene therapy in the treatment of a variety of inherited and acquired disorders. This application evaluates the role of liver inflammation in the efficacy and safety of liver-directed gene transfer. The results will be important in the selection of candidate diseases and design of clinical trials.

描述(由申请人提供)：本申请要求对项目I提供两年的修订支持，该项目名为“尿素周期障碍的基因治疗”，目前已进入资助的第二年。P0I的所有三个项目在推进应用程序的目标方面都取得了成效，并按照原来的时间表按期进行。项目I的具体目标3是评估炎症在AAV载体性能中的作用。该假说认为，使AAV转导的肝细胞易于被细胞毒性T淋巴细胞(CTL)杀伤的关键步骤是上调MHC I类分子并改善抗原提呈。一系列的收养迁移研究证实了这一假设。将LacZ特异性CTL转移到用AAV-LacZ转导肝脏的小鼠体内，除非动物在过继转移时接受Toll样受体(TLRs)的配体治疗，否则无法清除转基因表达；在这种情况下，转基因表达完全丧失，载体基因组完全清除，同时MHC I类分子上调。研究人员最近将这些研究扩展到该计划的范围之外，以评估先天免疫可能足以消除不依赖衣壳或转基因T细胞的转基因表达。事实上，他们显示，在AAV基因转移两周后，低剂量注射表达无关转基因的腺病毒载体与TLR配体足以完全取消AAV编码的转基因表达；载体基因组减少但不能消除，这表明转录关闭可能起到一定作用，也可能导致载体基因组的部分不稳定。此次修订旨在进一步评估炎症在抑制AAV载体转基因在肝脏表达中的作用。修订后的具体目标1将评估一些与研究人员最近观察到的重要问题有关的问题，包括：低剂量的Ad是通过产生CTL还是通过直接激活APC起作用？TLR配体是否通过参与其同源受体起作用？促炎细胞因子是必要的和/或充分的吗？最后，与常驻APC相比，通过肝细胞传递信号的相对作用是什么？修订后的特定目标2将利用小鼠模型来评估慢性肝炎感染对AAV载体性能的影响，当在基因转移时或在基因转移之后存在肝炎时。 相关性：腺相关病毒有望在多种遗传性和获得性疾病的治疗中实现肝脏导向的基因治疗。这项应用评估了肝脏炎症在肝脏导向基因转移的有效性和安全性中的作用。这一结果将对候选疾病的选择和临床试验的设计具有重要意义。