Scaffold-Mediated Gene Delivery for Engineering of Osteochondral Tissues

描述：受损或病变骨组织的再生仍然是一个重大的临床挑战，并导致人类残疾和不适。通过制造由细胞、生物活性因子和可生物降解支架组成的活组织替代品，组织工程和再生医学正在成为治疗这些疾病的有前途的策略。组织工程在创造均匀组织方面尤其成功，例如皮肤和软骨。然而，许多损伤和疾病影响组织之间的界面，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成功地将祖细胞和生物材料结合在体外工程组织中。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可以直接实践而且可以有效指导细胞分化和组织形成的方法，这些方法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大大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向细胞输送生物活性因子的方法。因此，植入这些支架上的干细胞或渗透到支架上的内源性祖细胞将被刺激产生不同的组织类型。在本研究中，我们将首先通过分化因子的空间调控基因转移，利用人间充质干细胞生成骨软骨组织。精确的空间控制将通过创新的生物材料介导的基因传递方法和用于创建3D聚合物支架的微尺度编织技术实现。然后，我们将把这种体外方法扩展到兔微骨折手术模型中，其中支架由来自骨髓的内源性祖细胞填充，这些细胞被指示根据支架的病毒转基因递送在原位形成组织。这项工作对于开发组织工程策略具有重要意义，可以创建复杂的结构，再现天然组织界面的异质性和功能，并最大限度地减少体外细胞操作。

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.