A Bioengineering Approach to Create Immunorejection Free Human Pancreatic Islets

描述（由申请人提供）：到2015年，预计美国将有十分之一的人口患有糖尿病。胰岛移植在治疗糖尿病方面具有巨大的潜力，但必须首先克服与胰岛存活、功能和免疫排斥相关的问题。结合生物工程和胰岛生物学有很大的潜力来克服这些挑战。我们已经报道了人骨髓（BM），无论是在体外还是在体内，都能显著改善人胰岛功能和存活率，但这种有益作用的机制在很大程度上是未知的。我们有初步的数据，BM通过启动血运重建和刺激人类胰岛再生来促进人类胰岛的体外存活和功能。为了解决人类胰岛的免疫排斥问题，我们提出了一种将人类胰岛/骨髓共培养物包封的生物工程方法，我们将使用植入功能性人类免疫系统的小鼠（人源化小鼠）在体内进行测试。我们假设共包封的脑脊髓瘤和胰岛创造了一个有利的微环境，通过这个微环境，脑脊髓瘤旁分泌的活性促进了人类胰岛的血运重建，增强了细胞的自我再生，并防止了免疫排斥。我们将研究BM如何在人源化小鼠中维持人类胰岛功能/生存和防止人类免疫排斥的机制，以及使用含有选定细胞因子的纳米颗粒局部释放到胰岛的益处。为了了解人类脑基质如何促进人类胰岛在封装微环境中的生存和功能，我们将(1)评估在封装胰岛和脑基质组织的3D构建中发生的血运重建和细胞再生；(2)在糖尿病人源化小鼠中，评估胰岛包被加BM克服人类免疫排斥和恢复葡萄糖稳态的能力，并确定半透性水凝胶胶囊中携带细胞因子的纳米颗粒是否通过募集祖细胞来促进功能胰岛包被的支持。(3)通过鉴定BM旁分泌血小板衍生生长因子（PDGF或其他因子）和Mir-RNA 24-2调节PDGF信号通路对胰岛生存和功能的影响，确定BM在封装微环境中增强人胰岛生存和功能的机制。我们的长期目标是确定被包裹的胰岛加上BM细胞在体内维持胰岛功能的机制，并在没有普遍免疫抑制的情况下防止胰岛排斥反应，并将其转化为临床。

DESCRIPTION (provided by applicant): By 2015, it is estimated that one tenth of the U.S. population will suffer from diabetes. Islet transplantation has great potential for the treatment o diabetes, but must first overcome issues associated with islet survival, function and immunorejection. Combining bioengineering and islet biology has great potential for overcoming these challenges. We have reported that human bone marrow (BM), either in vitro or in vivo, significantly improves human islet function and survival, but the mechanisms underlying this beneficial effect are largely unknown. We have preliminary data, that BM facilitates human islet survival and function in vitro by initiating revascularization and stimulating human islet regeneration. To address immunorejection of human islets, we propose a bioengineering approach of encapsulation of human islet/BM co- cultures and we will test this in vivo using mice engrafted with a functional human immune system (humanized mice). We hypothesize that co-encapsulated BM plus islets creates a favorable microenvironment via which BM paracrine activity facilitates revascularization of human islets, enhances ¿ cell self regeneration and prevents immunorejection. We will investigate mechanisms of how BM sustains human islet function/survival and prevents human immunorejection in humanized mice and the benefits of using nanoparticles with selected cytokines incorporated for local release to the islets. To understand how human BM facilities human islet survival and function within an encapsulated microenvironment, we will (1) evaluate revascularization and ¿-cell regeneration that occurs within a 3D construction of the encapsulated islet and BM tissues; (2) evaluate the ability of encapsulated islets plus BM to overcome human immunorejection and restore glucose homeostasis in diabetic humanized mice, and determine whether nanoparticles carrying cytokines in a semi-permeable hydrogel capsule facilitate support of encapsulated functional islets by recruiting progenitor cells, and (3) identify the mechanisms by which BM enhances human islet survival and function in an encapsulated microenvironment by identifying the effect of BM paracrine Platelet-derived growth factor (PDGF or other factors) and Mir-RNA 24-2 to modulate PDGF signaling pathways on islet survival and function. Our long term goal is to identify the mechanism(s) by which encapsulated islets plus BM cells sustain islet function in vivo and prevent islet rejection in the absence of generalized immunosuppression for translation to the clinic.