Functional Activation and Targeting of Exosomes for Regenerative Medicine

总结： 干细胞谱系测定（SCLD）是成功进行造血干细胞移植所必需的重要步骤。 由于疾病或损伤而丧失的组织的再生。现有的组织工程方法使用 生长因子和形态发生沿着相关生物材料以实现SCLD。然而，这种方法 SCLD受多种因素的限制，如剂量、递送、异位活性、不良免疫学反应、 并发症和异常分化。由于这些限制，单一形态发生素系统具有 导致严重的临床并发症（来自FDA批准的生长因子，如BMP 2）或已失败 才能取得成功小时的需要是这种单一形态/生长因子的替代品 这是一种仿生系统，不会对翻译造成同样的威胁。在这方面，使用 由于它们的仿生性质，它们被受体细胞内吞的能力， 细胞及其阳性免疫反应。然而，有两个基本问题需要调查， 帮助使用外来体作为纳米仿生工具，以实现再生医学中的SCLD。分别是：1. 外泌体可以靶向生物材料进行局部递送吗？2.外泌体的组成是否可以改变， 诱导组织特异性SCLD？这个应用程序是努力弥合这一知识差距。我们建议 将靶向性和谱系特异性功能性工程化到外泌体中以产生功能激活的 靶向外泌体（FATE）。在本申请中，我们将使用骨再生作为模型系统来研究骨再生。 再生医学FATE的产生、评价和应用。我们提出三个具体目标， 实现这一目标。在目标1中，我们将设计具有增强ECM蛋白结合特性的外泌体 I型胶原和纤连蛋白，以实现生物材料介导的位点特异性靶向。在目标2中，我们将 使用两种不同的方法将骨诱导功能工程化到靶向外泌体中，并评估 在体外产生的命运。在目标3中，我们将评估目标中生成的FATE的目标和功能 2在体内在临界尺寸的大鼠颅骨缺损模型中。这些研究的成功完成将作为 原理证明，细胞衍生的纳米囊泡（外来体）可以被工程化以具有以下特征： 需要增强SCLD以实现组织特异性再生。

Summary: Stem Cell Lineage Determination (SCLD) is a necessary and important step required for successful regeneration of tissues lost due to disease or injury. Existing tissue engineering approaches employ the use of growth factors and morphogens along with relevant biomaterials to achieve SCLD. However, this approach to SCLD is limited by several factors such as dosage, delivery, ectopic activity, adverse immunological complications and aberrant differentiation. As a result of these limitations, the single morphogen system has either caused significant clinical complications (from FDA approved growth factors such as BMP2) or has failed to be translationally successful. The need of the hour is a replacement for this single morphogen/growth factor system that is biomimetic in nature and does not pose the same threats to translation. In this regard, the use of exosomes can be beneficial owing to their biomimetic nature, their ability to be endocytosed by recipient cells and their positive immunological reactions. However, two fundamental questions need investigation to aid the use of exosomes as nano biomimetic tools to achieve SCLD in regenerative medicine. They are: 1. Can exosomes be targeted to biomaterials for localized delivery? 2. Can exosomal composition be modified to induce tissue-specific SCLD? This application is an effort to bridge this knowledge gap. We propose to engineer targetability and lineage-specific functionality into exosomes to generate Functionally Activated Targeted Exosomes (FATE). In this application, we will use bone regeneration as a model system to study the generation, evaluation and application of FATE for regenerative medicine. We propose three specific aims to achieve this goal. In Aim 1, we will engineer exosomes with enhanced binding characteristics to ECM proteins type I collagen and Fibronectin to enable biomaterial-mediated site-specific targeting. In Aim 2, we will engineer osteoinductive functionality into the targeting exosomes using two distinct approaches and evaluate the resulting FATE in vitro. In Aim 3, we will evaluate the targeting and functionality of FATE generated in aim 2 in vivo in a critical size rat calvarial defect model. The successful completion of these studies will serve as proof-of-principle that cell-derived nano vesicles (exosomes) can be engineered to possess characteristics required to enhance SCLD for tissue-specific regeneration.