Vector Targeting for Fracture Repair

描述(由申请人提供)：许多调查人员已经证明 表达骨形态发生蛋白2的腺病毒(Ad)载体可以 通过诱导类似于骨形成的骨形成来增强骨折修复 正常过程，与直接注射 重组蛋白。因此，通过Ad载体递送BMP2是一种 改善骨修复的有吸引力的策略，目前被推迟或 5%-10%的骨折病例不成功。一个主要的挑战是生产一种安全的 不识别表达成骨细胞的成骨细胞靶向载体 广泛性腺病毒，CAR，腺病毒感染的通常途径 哺乳动物细胞。这项建议旨在增加特定性和安全性 通过修饰病毒纤维蛋白(目标1)使其不再 结合CAR，但转而识别成骨细胞上的OST-PTP蛋白(AIM 2)。这些目标将通过去除关键的氨基酸序列来实现 在纤维DG环中，并监测细胞通过 汽车结合途径，并通过构建其纤维携带 CAR结合序列缺失和OST-PTP特异性抗体序列和 然后评估它们在体外和体内靶向成骨细胞的能力。 从这些研究中出现的载体将是插入 BMP2或其他与骨骼疾病相关的治疗基因。给定 申请者在腺病毒载体设计和翻译研究方面的经验 在大学和制药环境中，成功的前景 这个项目的成果似乎很高。

DESCRIPTION (provided by applicant): Many investigators have shown that adenoviral (Ad) vectors expressing the bone morphogenetic protein BMP2 can enhance fracture repair by eliciting bone formation that closely resembles the normal process, in contrast to results obtained with direct injection of the recombinant protein. Delivery of BMP2 via an Ad vector is therefore an attractive strategy for improving bone repair, which currently is delayed or unsuccessful in 5-10% of fracture cases. A major challenge is to produce a safe osteoblast-targeted vector that does not recognize cells expressing the widespread adenovirus, CAR, the usual route by which adenoviruses infect mammalian cells. This proposal seeks to increase the specificity and safety of Ad vectors by modifying the viral fiber protein (Aim 1) so that it no longer binds to CAR, but instead recognizes the OST-PTP protein on osteoblasts (Aim 2). These objectives will be pursued by ablating critical amino acid sequences in the fiber DG loop and monitoring cells for evidence of infection through the CAR-binding pathway, and by constructing vectors whose fiber carries both the CAR-binding sequence deletion and an OST-PTP-specific antibody sequence and then assessing their ability to target osteoblasts in vitro and in vivo. Vectors emerging from these studies will be prime candidates for insertion of BMP2 or other therapeutic genes with relevance to bone disease. Given the applicant's experience in adenoviral vector design and translational research in university and pharmaceutical settings, the prospects for a successful outcome of this project appear high.