Exosome-mediated Craniofacial Bone Tissue Engineering by Controlled Release

摘要 健康的骨骼对全身健康至关重要。与颅面复合体、牙种植体相关 在植入种植体和修复牙列之前，要求用骨填充空的牙槽。骨质量 骨量与牙种植体的短期和长期成功密切相关。 基于生物材料的骨再生有望克服骨移植的缺点。这些 生物材料可以用指导组织再生的指导性成分来功能化。外显体， 被认为是大自然的内源生物分子传递平台，特别有趣，因为它们的 与生俱来的生物兼容性和与细胞沟通以调节其表型的能力。最近的体外试验 数据表明，来自矿化MC3T3前成骨细胞的外体能够诱导 幼稚的骨髓基质细胞的矿化。然而，设计一种方法来有效地治疗 体内给药，在临床上和生物上相关的方式是外切体介导的治疗中的一个挑战。 该项目的总体治疗目标是开发内源性间充质细胞的再生能力。 干细胞通过聚合物组织工程构建来模拟外切体的自然分泌。我的 初步数据表明，通过可调节的生物可降解共聚物进行的聚合物自组装可以 包裹外体，随着时间的推移以持续的方式释放。我的中心假设是 从聚合物基质中控制释放成骨外体将促进颅面骨 治愈。 具体目标是1)开发一种受控良好的制造方法，允许将 将外切体释放方式转化为三维组织工程构建；2)评价组织工程的完整性 包埋和释放过程中具有生物活性的外切体含量及其引起表型的能力 下游细胞的变化；以及3)在两个体内模型中验证本文发明的技术。 颅面骨再生。拟议实验的结果将展示一种方法，以 聚合物基质中外切体的包裹和控制传递，形成头面部骨骼 无需干细胞移植即可再生。有效的外切体包裹和释放策略，这 保持它们的生物活性，对于推进外切体介导的临床治疗领域至关重要，这 可应用于多种组织类型的再生。

Abstract Healthy bone is critically important to systemic health. Of relevance to the craniofacial complex, dental implants require that empty sockets are filled with bone prior to implant placement and restoring dentition. Bone quality and bone amount are strongly correlated with both the short- and long-term success of dental implants. Biomaterials-based bone regeneration is promising to circumvent shortcomings of bone grafting. These biomaterials can be functionalized with instructive components which guide tissue regeneration. Exosomes, thought to be nature's endogenous biomolecule delivery platform, are particularly interesting because of their innate biocompatibility and capacity to communicate with cells to modulate their phenotype. Recent in vitro data suggests that exosomes derived from mineralizing MC3T3 pre-osteoblasts are able to induce mineralization in naive bone marrow stromal cells. However, engineering a means for their efficient therapeutic delivery in vivo, in a clinically and biologically relevant manner is a challenge in exosome-mediated therapy. The overall therapeutic goal of this project is to exploit the regenerative capacity of endogenous mesenchymal stem cells by mimicking the natural secretion of exosomes with a polymeric tissue engineering construct. My preliminary data suggests that polymeric self-assembly via a tunable biodegradable copolymer can encapsulate exosomes, which are released in a sustained fashion over time. My central hypothesis is that controlled release of osteogenic exosomes from a polymer matrix will promote craniofacial bone healing. The specific aims are to 1) develop a well-controlled fabrication method which allows incorporation of an exosome-releasing modality into a three-dimensional tissue engineering construct; 2) evaluate the integrity of the bioactive exosome contents during encapsulation and release, and their ability to cause phenotype changes in downstream cells; and 3) validate the technology invented herein in two in vivo models of craniofacial bone regeneration. The outcomes of the proposed experiments will demonstrate a means for the encapsulation and controlled delivery of exosomes from a polymer matrix, causing craniofacial bone regeneration without stem cell transplantation. Effective exosome encapsulation and release strategies, which preserve their biologic activity, are critical to advancing the field of exosome-mediated clinical therapies, which can be applied to the regeneration of many tissue types.