Selection of Therapeutic Agents for Articular Cartilage Repair

描述(由申请人提供)： 关节软骨是腹股沟关节的滑动面。关节软骨的丧失，由于创伤或骨关节炎，是疼痛和残疾的主要原因。目前的治疗方法是解决软骨丢失引起的症状。需要治疗来纠正软骨本身的丢失。从理论上讲，实现这一目标的一种方法是用成纤维细胞生长因子-2(FGF-2)和胰岛素样生长因子-I(IGF-I)等细胞调节分子刺激软骨细胞。第二种方法是使用软骨结构分子，如胶原蛋白和聚集素，用来构建新的软骨。目前尚不清楚这些替代方法如何相互比较，也不知道它们是否可以组合在一起。这项提案试图回答这些问题。这项研究将在软骨修复的体外模型中使用基于细胞的基因疗法来检验以下假设。目的：确定成纤维细胞生长因子-2(成纤维细胞生长因子-2)基因治疗能否在不诱导损伤促进活性的情况下诱导修复促进活性。假设1A：高表达的成纤维细胞生长因子-2的修复促进和损伤促进作用是由特定的成纤维细胞生长因子-2亚型选择性地介导的，因此特定的成纤维细胞生长因子-2亚型将优先促进新的软骨形成。假设1B：成纤维细胞生长因子-2亚型作用的机制涉及亚细胞亚型的不同定位。目的：确定基质基因治疗是否能促进关节软骨修复。假设2A：II型胶原或聚集素的过度表达增加了新的软骨形成。假设2B：在产生新的软骨形成方面，II型胶原和聚集素的过度表达都优于单独表达其中任何一种。目的：确定生长因子基因和基质基因联合使用的基因治疗在促进关节软骨修复方面是否优于单独使用任何一种药物的基因治疗。假设3A：将选定的成纤维细胞生长因子-2亚型和IGF-I基因与胶原蛋白和聚集素基质基因一起输送，比单独使用任何一类药物都能更大程度地增加新的软骨形成。假设3B：人关节软骨细胞对基因转移的反应方式与牛关节软骨细胞相似。修复将使用组织学、生化和分子生物学参数进行评估。这些研究的长期目标是选择适合临床应用的软骨修复基因治疗药物。 公共卫生相关性： 项目叙述和与退伍军人健康的相关性关节软骨丢失对美国退伍军人来说是一个悬而未决的问题。它影响到遭受创伤的年轻退伍军人和患关节炎的老年退伍军人。1999财政年度退伍军人管理局全国患者护理数据库确认了超过26万名患有骨关节炎的退伍军人(Jones A等人，2005年)。尽管有大量不同的治疗方案被用于治疗软骨损伤，但问题正变得越来越严重。据估计，仅就膝关节而言，由于目前的治疗方法缺乏疗效，到2030年将有85%的关节置换(Mamlin LA等人，1998年)。目前的治疗方法能够减少软骨丢失引起的症状，但缺乏能够纠正软骨丢失本身的治疗方法。这项研究旨在确定哪些潜在的治疗剂是关节软骨基因治疗的良好候选者。

DESCRIPTION (provided by applicant): Articular cartilage is the gliding surface of diarthrodial joints. The loss of articular cartilage, through trauma or osteoarthritis, is a major cause of pain and disability. Current treatments address the symptoms that result from cartilage loss. Treatments are needed that correct the cartilage loss itself. One approach to accomplishing this is, in theory, to stimulate the cartilage cells with cell-regulatory molecules such as fibroblast growth factor-2 (FGF-2) and insulin-like growth factor-I (IGF-I). A second approach is to employ cartilage structural molecules, such as collagen and aggrecan, with which to build new cartilage. It is not known how these alternative approaches compare with each other, or whether they can be combined. This proposal seeks to answer these questions. The studies will employ cell-based gene therapy in an ex vivo model of cartilage repair to test the following hypotheses. Objective 1: Determine whether gene therapy with fibroblast growth factor-2 (FGF-2) can induce repair-promoting activity without also inducing damage-promoting activity. Hypothesis 1A: The repair-promoting and damage-promoting actions of overexpressed FGF-2 are selectively mediated by specific FGF-2 isoforms and therefore specific FGF-2 isoforms will preferentially augment new cartilage formation. Hypothesis 1B: The mechanism of FGF-2 isoform action involves differential subcellular localization of the isoforms. Objective 2: Determine whether gene therapy using matrix genes augments articular cartilage repair. Hypothesis 2A: Overexpression of type II collagen or of aggrecan increases new cartilage formation. Hypothesis 2B: Overexpression of both type II collagen and aggrecan is superior to overexpression of either alone in generating new cartilage formation. Objective 3: Determine whether gene therapy with growth factor genes and matrix genes in concert is superior to gene therapy employing either class of agent alone in improving articular cartilage repair. Hypothesis 3A: Delivery of selected FGF-2 isoform and IGF-I genes together with collagen and aggrecan matrix genes increases new cartilage formation to a greater degree than either class of agent alone Hypothesis 3B: Human articular chondrocytes respond to gene transfer in a fashion similar to that of bovine articular chondrocytes. Repair will be assessed using histological, biochemical, and molecular biological parameters. The long-term goal of these studies is to select gene therapy agents for cartilage repair that are suitable for clinical application. PUBLIC HEALTH RELEVANCE: Project Narrative and Relevance to Veterans' Health Articular cartilage loss is an unsolved problem for American veterans. It affects young veterans who have sustained trauma and aging veterans who develop arthritis. The Veterans Administration National Patient Care Database for fiscal year 1999 identified over 260,000 veterans with osteoarthritis (Jones A et al, 2005). Despite the large and diverse number of therapeutic options being used to treat cartilage damage, the problem is getting worse. It has been estimated that, for knee joints alone, there will be an 85% in joint replacements by 2030 due to the lack of efficacy of current treatments (Mamlin LA et al, 1998). Current therapies are able to decrease the symptoms that result from cartilage loss, but treatments are lacking that can correct the cartilage loss itself. This research project is designed to determine which potential therapeutic agents are good candidates for articular cartilage gene therapy.