Collaborative Research: Composite vascularized niches for optogenetically actives beta-cells

生物人工组织的设计和制造带来了巨大的挑战，但对于开发有效的重大疾病治疗方法是必不可少的。这类组织通常需要大量的功能细胞，如果没有促进营养物质和氧气的运输以及废物的清除的血管系统，这些细胞就无法生存。减少必要的细胞数量的一种方法是利用光作为刺激来放大它们的功能。基于以前的工作，在蓝光刺激下，胰腺分泌胰岛素的β细胞在葡萄糖刺激下的胰岛素分泌量增加了2到3倍。此外，使用合适的生物材料可以促进合成组织中血管网络的形成。该项目旨在利用为治疗糖尿病而开发的新型胰腺组织等效物，开发具有光激活细胞的可植入工程组织的设计原则并解决基本的生物学问题。糖尿病困扰着近10%的美国人口，医疗费用最高。所有1型糖尿病患者和30%的2型糖尿病患者完全依赖外源性胰岛素的注射。然而，血糖控制是次优的，并不能避免严重的长期并发症。该项目将通过生物材料发现和创新以及细胞和组织工程来解决这些问题，从而推动提高糖尿病患者生活质量的相关技术。这项研究与教育活动交织在一起，包括对STEM领域的本科生和研究生进行跨学科培训，向K-12学生和公众推广，以及促进生物工程科学的多样性。该项目的驱动因素是开发可植入工程组织以重建重要的身体过程，如血糖(BG)动态平衡。这样的组织需要大量的细胞和支持血管网络的形成，这通常需要几周的时间。为了满足这一需求，该项目建议使用光基因工程人β细胞，这种细胞在光照下表现出2-3倍的葡萄糖刺激的胰岛素分泌(GSI)，以改善糖尿病高血糖。首先，将用海藻酸盐包裹的产氧微粒(OGM)和光基因工程人β细胞设计和构建基于明胶的工程化组织。将确定必要的设计参数，如细胞与支持OGMs的比例和水凝胶配方。在对复合水凝胶进行表征后，人内皮细胞将被结合到支架中形成血管网络。在存在光基因工程的葡萄糖反应的β细胞的情况下，将建立支架内血管生成的条件。最后，工程化组织的功能将在糖尿病小鼠模型中进行评估。这项研究将解决在使用光激活细胞、合成组织中的血管网络形成以及将细胞与合适的生物材料连接以实现最佳体内功能方面的独特障碍。这些都是设计用于治疗糖尿病等重大疾病的可调组织系统的普遍考虑因素。此外，这里开发的具有可光激活的人类β细胞的组件将是β细胞生理学基础研究的急需资源。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The design and manufacturing of bioartificial tissues pose great challenges yet are essential for developing effective therapies for major diseases. Such tissues typically require a large number of functional cells, which cannot survive without vasculature that facilitates the transport of nutrients and oxygen and the removal of waste products. One way to reduce the requisite number of cells is to amplify their function using light as the stimulus. Based on previous work, pancreatic insulin-producing β-cells exhibit 2- to 3-fold higher glucose-stimulated insulin secretion when stimulated with blue light. Moreover, vascular network formation in synthetic tissues can be promoted with the use of appropriate biomaterials. This project seeks to develop design principles and address fundamental biological issues of implantable engineered tissues with light-activatable cells utilizing a novel pancreatic tissue equivalent developed for the management of diabetes. Diabetes afflicts almost 10% of the US population with the highest healthcare costs. All persons with type 1 diabetes and 30% of those with type 2 diabetes rely exclusively on the administration of exogenous insulin. However, blood glucose control is suboptimal and does not avert serious long-term complications. The project will address these issues through biomaterial discovery and innovation and cell and tissue engineering, thereby advancing relevant technologies that improve the quality of life of persons with diabetes. The research is intertwined with educational activities including interdisciplinary training for undergraduate and graduate students in STEM fields, outreach to K-12 students and the public, and promoting diversity in bioengineering sciences.This project is driven by a critical need to develop implantable engineered tissues for reconstituting vital bodily processes such as blood glucose (BG) homeostasis. Such tissues require significant numbers of cells and the formation of a supporting vascular network, which typically spans a few weeks. To address this need, this project proposes the use of optogenetically engineered human β-cells, which show 2- to 3-fold greater glucose-stimulated insulin secretion (GSIS) with illumination, to ameliorate diabetic hyperglycemia. First, a gelatin-based engineered tissue will be designed and constructed with oxygen-generating microparticles (OGMs) and optogenetically engineered human β-cells encapsulated in alginate. Essential design parameters such as the ratio of cells to supporting OGMs and the hydrogel formulation will be determined. Upon characterization of the composite hydrogels, human endothelial cells will be incorporated into the scaffolds to form a vascular network. Conditions will be established for intra-scaffold angiogenesis in the presence of optogenetically engineered, glucose-responsive β-cells. Finally, the functionality of the engineered tissue will be evaluated in a mouse model of diabetes. The research will address unique hurdles in the use of light-activatable cells, vascular network formation in synthetic tissues, and interfacing cells with suitable biomaterials for optimal in vivo function. These are universal considerations in the design of tunable tissue systems for the treatment of major maladies such as diabetes. Additionally, assemblies with photoactivatable human β-cells developed here will be a much-needed resource for basic research on β-cell physiologyThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.