Central Nervous System Tissue Organogenesis via Precise Growth Factor Tethering

 描述（由申请人提供）：脊髓损伤（SCI）导致脊髓受损区域以下的感觉输入和运动功能永久丧失。目前没有可用的治疗SCI恢复失去的功能。一个令人兴奋的前瞻性策略是管理干细胞再生和功能恢复受损的脊髓组织。然而，这种方法充满了挑战，因为递送的细胞缺乏成功整合和结果所必需的指导性线索;大多数临床工作只是用干细胞治疗患者，这证明不足以治疗SCI。基于生物材料的策略为这一挑战提供了一个解决方案：而不是期望干细胞整合在细胞表面。 我们可以为他们提供一个支持结构和必要的指导性线索。我们已经证明，一种天然来源的水凝胶材料，甲基丙烯酰胺壳聚糖（MAC），可以安全地封装成体神经干细胞（aNSCs），并提供体内移植所需的仿生基质。此外，我们可以忽略重要的谱系指定信号， 通过蛋白质工程和点击化学的独特应用，将蛋白质转化为这种材料。最近，我们发现，当暴露于皮下环境时，包封在基于MAC的神经引导导管内并具有单个固定的神经源性融合蛋白的aNSC将形成发育中的神经上皮。这一点很重要，因为神经上皮是成熟中枢神经系统（CNS）组织的未成熟前体。因此，我们假设我们的工程管道可以在皮下组织内异位成熟，然后移植到受损的脊髓中，在那里它会发育并与受损组织整合。这种新的SCI治疗模式将通过两个目标来实现。首先，我们的目标是量化和证实导致植入皮下组织的结构中新生神经管形成的环境。第二，我们的目标是改进和实施皮下成熟的结构来治疗SCI。随着我们在这个项目中的进展，所获得的信息不仅对治疗SCI有用， 帮助理解干细胞与生物材料相互作用的复杂行为。

 DESCRIPTION (provided by applicant): Spinal cord injury (SCI) results in permanent loss of sensory input and motor function below the damaged region of the spinal cord. There is currently no available treatment for SCI to recover lost function. One exciting prospective strategy is the administration of stem cells to regenerate and functionally restore damaged spinal cord tissue. However, this approach is fraught with challenges as delivered cells lack the instructive cues necessary for successful integration and outcomes; most clinical work simply transfuses patients with stem cells which proves insufficient for treating SCI. Biomaterial-based strategies offer a solution to this challenge: rather than expecting the stem cells to integrate on their own, we can provide them with a support structure and the necessary instructive cues. We have shown that a naturally-derived hydrogel material, methacrylamide chitosan (MAC), can safely encapsulate adult neural stem cells (aNSCs) and provide a biomimetic matrix necessary for in vivo transplantation. Additionally, we can immobilize important lineage-specifying signaling proteins to this material through a unique application of protein engineering and click chemistry. Recently, we discovered that, when exposed to the subcutaneous environment, aNSCs encapsulated within a MAC-based neural guidance conduit and with a single immobilized neurogenic fusion protein will form developing neural epithelium. This is important, as neural epithelium represents an immature precursor to mature central nervous system (CNS) tissue. Thus, we hypothesize that our engineered conduit could be matured ectopically within the subcutaneous tissue and then transplanted into a damaged spinal cord, where it would develop and integrate with damaged tissue. This new SCI treatment paradigm will be approached through two aims. First, we aim to quantify and substantiate the environment that leads to the formation of nascent neural tubes in constructs implanted in subcutaneous tissue. Second, we aim to improve and implement the subcutaneous- matured construct to treat SCI. As we progress through this project, the information gained will be of use not only to treat SCI but also to help understand the complex behavior of stem cell-biomaterial interactions.