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

成体神经干细胞（NSCs）在治疗神经系统损伤或疾病方面具有巨大的潜力。然而，这些细胞很罕见，很难在培养中维持，因为它们在离开原生环境后很快就失去了多能性。在体内，NSCs位于血管生态位附近，这表明如果在培养环境中重建血管生态位的关键功能特征，则可能在体外维持这些细胞。提出的研究假设是，在3-D细胞外基质中形成灌注的功能性脉管系统促进周围NSCs的自我更新。为了验证这一假设，将追求以下具体目标：1)使用新颖的细胞打印技术在3d基质中创建一个包含灌注血管和NSCs的神经血管单元。2)从基质性质和培养参数方面建立合成结构的成熟过程和功能。3)利用工程神经血管单元检测NSC行为和细胞命运；并确定影响NSC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3-D灌注血管生态位，在一个生理学相关的实验系统中研究NSCs，在这个实验系统中，单个组件和参数可以很容易地操纵。利用该系统，本研究将明确实现血管功能的关键因素，并阐明动态灌注系统中NSC自我更新的潜在机制。由于血管系统是许多成体干细胞龛的关键因素，这项研究将在研究其他干细胞领域产生更广泛的影响。总的来说，这项工作将确定打印结构的设计原则和操作参数，以支持体外周围组织的生长，从而为未来生物医学应用制造适当厚度的组织奠定基础。更广泛的影响：拟议的研究在产生与三维维管组织形成及其在调节NSC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，所提出的研究有望帮助开发出患者特异性NSCs体外扩增治疗脊髓损伤和神经退行性疾病的方法，这将使患者和整个社会受益。研究将与针对K-12教育和代表性不足群体的教育和推广活动结合起来。展示工程师如何解决社会挑战的活动将激励学生从事科学和工程方面的职业。

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.