Utility of AAV Serotypes for Gene Delivery in Treatment of Chronic Joint Disease

描述（由申请人提供）：骨关节炎（OA）是一种无法治愈的慢性衰弱性疾病。有强有力的证据表明，白细胞介素-1（IL-1）是OA中软骨损失、疼痛和炎症的关节内介质。其天然抑制剂IL-1受体拮抗剂（IL-1 Ra）有望成为一种有效的治疗方法，但临床应用受到难以达到和维持关节内有效浓度的阻碍。我们致力于开发将IL-1 Ra的cDNA递送到关节囊组织中的细胞的技术，使得这些组织成为持续升高的IL-1 Ra产生的内源性位点。这种基于基因的方法消除了重复应用重组蛋白的需要，同时在疾病部位特异性地提供最大浓度的基因产物。某些重组病毒载体的直接关节内注射可以提供治疗性转基因的表达，其水平足以在小动物模型中停止关节炎。通过使用免疫相容性载体和cDNA，外源转基因可以在填充被膜组织的细胞中无限表达。腺相关病毒（AAV）提供了许多优势，有利于其作为治疗关节炎的基因递送载体的使用。双链（自身互补[sc]）载体和替代衣壳血清型的开发克服了先前的缺陷，使得AAV可以实际地被认为是用于OA中的人类应用的候选者。本研究将检验scAAV介导的IL-1 Ra的cDNA局部递送至患有OA的关节将提供持续的治疗益处的假设。马为研究关节内基因转移治疗关节疾病提供了一个独特的系统。他们的关节大小与人类膝盖成比例，并且容易受到OA的影响。在特定目标1和2中，我们将通过在马关节中进行药代动力学研究，表征同源马IL-1 Ra（eqIL-1 Ra）cDNA递送后的生物分布和转基因表达模式，确定scAAV作为人类规模关节的基因递送系统的效用。从研究的这一部分中获得的经验教训将用于具体目标3中，以评价scAAV介导的eqIL-1 Ra递送抑制马中OA的骨软骨碎裂模型的病理学的能力。通过以这种方式研究scAAV-IL-1 Ra基因治疗的功效-在适当的规模和相关的疾病背景下-将出现其治疗能力的明确表示。如果成功，这些研究将提供必要的药代动力学，安全性和有效性数据，以支持人体试验的实施。 公共卫生相关性：本研究旨在探索骨关节炎局部基因治疗的有效性。它包括将含有基因的重组病毒载体注射到关节中，这些基因的产物保护软骨免受退化。为了检查该程序在人类规模上的有用性，我们将在马的前肢关节中进行安全性和有效性研究。这些关节的大小与人类膝盖成比例，它们自然会发展为骨关节炎。这些研究的信息将用于支持人体临床试验。

DESCRIPTION (provided by applicant): Osteoarthritis (OA) is chronic, debilitating condition for which there is no cure. There is strong evidence that interleukin-1 (IL-1) serves as an intra-articular mediator of cartilage loss, pain and inflammation in OA. Its natural inhibitor, the IL-1 receptor antagonist (IL-1Ra), holds promise as an effective treatment, but clinical application is hindered by difficulty achieving and maintaining effective concentrations intra-articularly. We have worked to develop technologies for delivering the cDNA for IL-1Ra to cells in the capsular tissues of joints, such that these tissues become endogenous sites of sustained, elevated IL-1Ra production. This gene-based approach removes the need for repeated application of the recombinant protein while providing the greatest concentration of the gene product specifically at the site of disease. Direct intra- articular injection of certain recombinant viral vectors can provide expression of therapeutic transgenes at levels sufficient to halt arthritis in small animal models. With the use of immunologically compatible vectors and cDNAs, exogenous transgenes can be expressed indefinitely in cells that populate the capsular tissues. Adeno-associated virus (AAV) offers many advantages that favor its use as a gene delivery vehicle for treatment of arthritis. The development of double-stranded (self-complementary [sc]) vectors and alternate capsid serotypes overcomes previous deficiencies such that AAV can be realistically considered as a candidate for human application in OA. The present study will test the hypothesis that scAAV- mediated delivery of the cDNA for IL-1Ra locally to joints with OA will provide sustained therapeutic benefit. Horses provide a unique system in which to study intra-articular gene transfer for joint disease. Their joints are proportional in size to human knees, and they are vulnerable to the onset of OA. In Specific Aims 1 and 2 we will work to determine the utility of scAAV as a gene delivery system to joints of human scale by performing pharmacokinetic studies in equine joints, characterizing biodistribution and transgenic expression patterns following delivery of the cDNA for the homologous equine IL-1Ra (eqIL-1Ra). Lessons learned from this part of the study will be used in Specific Aim 3 to evaluate the capacity of scAAV- mediated delivery of eqIL-1Ra to inhibit the pathologies of an osteochondral fragmentation model of OA in horses. By studying the efficacy of scAAV-IL-1Ra gene therapy in this manner- on an appropriate scale and in a relevant disease context- a clear representation of its therapeutic capacity will emerge. If successful these studies will provide the necessary pharmacokinetic, safety and efficacy data to support the implementation of human trials. PUBLIC HEALTH RELEVANCE: This study is designed to explore the usefulness of a local gene therapy for osteoarthritis. It involves the injection into the joint of recombinant viral vectors containing genes, whose products protect the cartilage from degeneration. To examine the usefulness of this procedure on a human scale, we will perform safety and efficacy studies in the forelimb joints of horses. These joints are proportional in size to human knees, and they naturally develop osteoarthritis. Information from these studies will be used to support clinical trials in humans.