CAREER: ENGINEER A FUNCTIONAL 3-D VASCULAR NICHE TO SUPPORT NEURAL STEM CELL SELF-RENEWAL

成人神经干细胞(NSCs)在治疗神经系统损伤或疾病方面具有巨大的潜力。然而，这些细胞很稀有，很难在培养中保持，因为它们在被从自然环境中移走后很快就失去了多潜能。在体内，神经干细胞与血管壁龛相邻，这表明如果在培养环境中重建血管壁龛的关键功能特征，那么在体外维持这些细胞是可能的。所提出的研究假设是，在三维细胞外基质内形成灌流的、有功能的血管系统促进周围神经干细胞的自我更新。为了验证这一假设，将追求以下具体目标：1)使用新的细胞打印技术在3-D基质中创建包含灌流血管和神经干细胞的神经血管单元。2)根据基质性质和培养参数确定合成结构的成熟过程和功能。3)使用工程化神经血管单元检测神经干细胞的行为和细胞命运；确定影响神经干细胞命运的关键因素及其与血管功能状态的关系。智力优势：拟议的研究将建立一个三维灌流的血管生态位，以在生理相关的实验系统中研究神经干细胞，其中单个组件和参数可以很容易地操纵。利用这一系统，这项拟议的研究将定义实现血管系统功能的关键因素，并将阐明动态灌流系统中神经干细胞自我更新的潜在机制。由于血管系统是许多成体干细胞生境的关键因素，这项研究将对其他干细胞领域的研究产生更广泛的影响。总之，这项工作将确定打印结构的设计原则和操作参数，以支持周围组织的体外生长，从而为未来构建适合生物医学应用的厚度合适的组织奠定基础。广泛影响：拟议的研究在产生与三维血管组织形成及其在调控神经干细胞命运中的作用相关的基础知识方面具有更广泛的科学影响。因此，拟议的研究有望帮助开发患者特异性神经干细胞体外扩增的方法，以治疗脊髓损伤和神经退行性疾病，这将造福于患者和整个社会。研究将与针对K-12教育和代表性不足群体的教育和外联活动结合起来。展示工程师如何解决社会挑战的活动将激励学生在科学和工程领域追求职业生涯。

1350240DaiAdult neural stem cells (NSCs) have great potential for treating damage or disease of the nervous system. However, these cells are rare and difficult to maintain in culture because they quickly lose their multi-potency after being removed from their native environment. In vivo, NSCs reside adjacent to a vascular niche, suggesting that it may be possible to maintain these cells ex vivo if critical functional features of the vascular niche are recreated in the culture environment.The hypothesis of the proposed studies is that formation of a perfused, functional vasculature within 3-D extracellular matrix promotes self-renewal of the surrounding NSCs. To test this hypothesis, the following specific aims will be pursued: 1) Create a neurovascular unit that contains perfused vasculature and NSCs within 3-D matrix using a novel cell printing technology. 2) Establish the maturation process and functionalities of the synthesized structures with regard to matrix properties and culture parameters. 3) Examine the NSC behavior and cell fate using the engineered neurovascular unit; and determine critical factors that influence NSC fate and its relationship to the functional status of the vasculature.Intellectual Merit: The proposed research will build a 3-D perfused vascular niche to study NSCs in a physiologically relevant experimental system, in which individual components and parameters can be easily manipulated. Using this system, the proposed research will define critical factors to achieve functionality of the vasculature and will elucidate underlying mechanisms of NSC self-renewal in the dynamically perfused system. Since vasculature is a key element of many adult stem cell niches, this research will have broader ramifications in studying other stem cell fields. Overall, this work will identify design principles and operating parameters for the printed structures to support the growth of the surrounding tissues in vitro, and thereby lay the foundation to fabricate tissues of appropriate thickness for biomedical applications in the future.Broader Impacts: The proposed research has broader scientific impact in generating fundamental knowledge related to 3-D vascular tissue formation and its role in regulating NSC fate. Therefore, the proposed studies are expected to help develop methods for the ex vivo expansion of patient-specific NSCs to treat spinal cord injury and neurodegenerative diseases, which will benefit patients and the society at large. Research will be integrated with educational and outreach activities targeting K-12 education and underrepresented groups. Activities demonstrating how engineers can solve societal challenges will provide incentives to students to pursue careers in science and engineering.