Scaffold-Mediated Gene Delivery for Engineering of Osteochondral Tissues

描述：受损或患病的骨骼组织的再生仍然是人类残疾和不适的重大临床挑战和原因。组织工程和再生医学是治疗这些疾病的有希望的策略，通过创造由细胞、生物活性因子和可生物降解的支架组成的活组织替代品。组织工程学在创造均匀的组织方面尤其成功，例如皮肤和软骨。然而，许多损伤和疾病会影响组织之间的界面，例如骨和软骨之间的过渡。许多针对这些更复杂组织的再生医学研究已经在结合祖细胞和生物材料的体外组织工程中取得了成功。然而，这些方法通常需要复杂、费力和昂贵的程序来进行细胞分离、扩增和体外细胞条件调节，以实现适当的细胞分化和组织形成。一个主要的挑战是将这些有希望的临床前研究转化为不仅简单实用，而且有效地指导细胞分化和组织形成的方法，这概括了自然组织的复杂性。利用细胞工程的进步，但尽量减少体外细胞操作的技术，可以极大地增强再生医学的前景。该项目开发了一种在三维支架内以精确的空间模式将生物活性因子输送到细胞的方法。因此，种植到这些支架上的干细胞或渗透到支架中的内源性祖细胞将受到刺激，以预定义的模式产生不同的组织类型。在本研究中，我们将首先利用人间充质干细胞通过空间可控的分化因子基因转移来生成骨软骨组织。通过生物材料介导的基因传递的创新方法和用于创建3D聚合物支架的微型编织技术，精确的空间控制将成为可能。然后，我们将把这种体外方法扩展到微骨折手术的兔模型中，在该模型中，支架由来自骨髓的内源性祖细胞填充，这些细胞被指示基于支架上的病毒转基因输送在原位形成组织。这项工作对开发组织工程策略以创建复杂结构具有重要意义，这些结构概括了天然组织界面的异质性和功能，并最大限度地减少了体外细胞操作。

DESCRIPTION: The regeneration of damaged or diseased skeletal tissues remains a significant clinical challenge and cause for human disability and discomfort. Tissue engineering and regenerative medicine are emerging as promising strategies for treating these conditions by creating living tissue substitutes composed of cells, bioactive factors, and a biodegradable scaffold. Tissue engineering has been particularly successful in creating uniform tissues, such as skin and cartilage. However, many injuries and diseases affect the interfaces between tissues, such as the transition between bone and cartilage. Many regenerative medicine studies that address these more complex tissues have been successful in engineering tissues in vitro with combinations of progenitor cells and biomaterials. However, these approaches typically require elaborate, laborious, and expensive procedures for cell isolation, expansion, and in vitro cell conditioning for proper cell differentiation and tissue formation. A primary challenge has been the translation of these promising preclinical studies into methods that are not only straightforward to practice but also effectively direct cell differentiation and tissue formation tat recapitulates the complexity of natural tissues. Technologies that capitalize on advances in cell engineering but minimize in vitro cell manipulation can greatly enhance the promise of regenerative medicine. This project develops a method to deliver bioactive factors to cells in a precise spatial pattern within a three dimensional scaffold. As a result, stem cells seeded onto these scaffolds or endogenous progenitor cells that infiltrate the scaffold will be stimulated to produce different tissue types in predefined patterns. In this study, we will first generate osteochondral tissues with human mesenchymal stem cells through spatially controlled gene transfer of differentiation factors. Precise spatial control will be enabled by innovative methods of biomaterial-mediated gene delivery and a microscale weaving technique for creating 3D polymer scaffolds. We will then expand this in vitro approach to a rabbit model of microfracture surgery, where the scaffold is populated by endogenous progenitor cells from the bone marrow that are instructed to form tissues in situ based on viral transgene delivery from the scaffold. This work is significant to developing tissue engineering strategies for creating complex structures that recapitulate the heterogeneity and function of native tissue interfaces and minimize in vitro cell manipulations.