Targeting the Extracellular Matrix to Inhibit Saphenous Vein Graft (SVG) Failure

描述（由申请人提供）：本提案的目标是Matrexa开发一种蛋白质产品，用于预防人隐静脉移植物（SVG）中的内膜增生，目的是降低这些外科手术的极高失败率。该策略包括在手术时使用Matrexa开发的专有药物对隐静脉进行急性预处理。干预的目标是大血管基质蛋白聚糖，多功能蛋白聚糖，其是平滑肌生长和增生、致动脉粥样硬化脂质积累和巨噬细胞进入发展中病变的中心。我们已经成功地靶向多能蛋白聚糖，并通过过表达小变体多能蛋白聚糖V3（V3）和过表达多能蛋白聚糖反义序列来预防动脉粥样硬化动物模型中的这些事件。我们还发现了这些方法的额外的和意想不到的益处，因为V3促进弹性纤维的合成和形成，并显著改善所治疗血管的机械性能和稳定性。一旦形成，弹性纤维将保持血管壁的结构完整性、抗增生和抗炎性质。我们通过缺失研究进一步发现，V3的外显子3含有这种弹性蛋白生成活性。然而，我们认识到，由于安全性和其他原因，V3的基因递送和过表达在治疗上是有问题的，因此我们提出开发和使用rV3蛋白和小肽作为治疗剂。在初步研究中，我们已经成功地生产了具有弹性蛋白活性的rV3。该项目的目的是1）制备足够数量和纯度的rV3蛋白，以在生物化学和体外细胞试验中检测其生物活性，2）证明rV3在人隐静脉离体培养物中预防内膜增生和促进弹性细胞生成的有效性。

DESCRIPTION (provided by applicant): The goal of this proposal is for Matrexa to develop a protein product that will prevent intimal hyperplasia in human saphenous vein grafts (SVG) with the objective of reducing the exceedingly high failure rate of these surgical procedures. The strategy involves acute pre-treatment of saphenous veins at the time of surgery with proprietary agents, developed by Matrexa. The target for intervention is the large vascular matrix proteoglycan, versican, which is central to smooth muscle growth and hyperplasia, accumulation of atherogenic lipids, and macrophage ingress into developing lesions. We have successfully targeted versican and prevented these events in animal models of atherosclerosis through over expression of the small variant versican V3 (V3) and through over expression of versican antisense sequences. We have also discovered an additional and unexpected benefit of these approaches in that V3 promotes the synthesis and formation of elastic fibers and markedly improves the mechanical properties and stability of treated vessels. Once formed, the elastic fibers will maintain the structural integrity, anti-hyperplastic and anti-inflammatory nature of the vascular wall. We have further discovered, through deletion studies, that exon 3 of V3 contains this elastogenic activity. We recognize, however, that gene delivery and overexpression of V3 is therapeutically problematic for safety and other reasons and we therefore propose to develop and use rV3 protein and small peptides as therapeutic agents. In preliminary studies we have been successful in producing rV3 which possesses elastogenic activity. The Aims of the project are 1) to prepare rV3 protein in enough quantity and purity to test its bioactivity in biochemical and in vitro cell-based assays and 2) to demonstrate the efficacy of rV3 to prevent intimal hyperplasia and promote elastogenesis in ex vivo cultures of human saphenous vein.