Designer Tregs for restoring tolerance in patients with type 1 diabetes

摘要 在I型糖尿病中，胰岛被自身免疫反应破坏。因此，一个总的战略目标 预防胰岛丢失的方法是局部抑制这种自身免疫反应，同时避免全身免疫。 压制。Foxp3表达的T调节细胞(Tregs)是一种免疫细胞，在局部免疫中发挥核心作用 因此，它可能成为预防胰岛丢失的细胞疗法的潜在平台。Tregs有 作为一种抑制性细胞疗法，它们有许多吸引人的特性：它们可以发挥主导的免疫抑制作用， 通过细胞间的相互作用或产生抑制性细胞因子；原则上它们可以长寿；以及 由Treg诱导的耐受性可以通过赋予Tregs的耐受性而持续到感染耐受性 相邻的细胞。在小鼠模型中，单次注射Tregs可以无限期地预防和逆转糖尿病。 在小鼠模型中令人鼓舞的初步数据有助于正在进行的临床试验的发展 人类的Treg细胞疗法。尽管如此，Treg细胞疗法面临着几个关键挑战：很难 它们特别针对小岛，并避免系统性抑制，它们很难充分扩张 数量(特别是相对于传统的效应器T细胞)及其细胞命运可以改变，特别是在 特殊的炎性微环境。然而，在过去的几年里，出现了引人注目的 将传统T细胞用于癌症治疗的进展(例如CAR T细胞)，包括新的 合成生物学工具，可以用来精确地将T细胞靶向疾病组织，控制它们的命运，并 这是为了防止核扩散，甚至使它们有能力在当地提供非天然的治疗有效载荷。在这里我们的 目标是利用这些新工具来解决工程改良的胰岛特异性治疗问题 抑制性细胞。我们的目标是： 1)利用改进的胰岛定位和识别来设计自然树 2)开发工具以选择性地在体内扩展治疗Tregs并增强其稳定性 3)设计合成抑制细胞，解除效应器的武装，抑制炎症，促进胰岛修复 这些方法结合了尖端合成生物学和开发治疗方法的多种策略 抑制细胞。我们将使用自身免疫性糖尿病的小鼠模型建立概念验证数据，并 将它们应用于使用人源化的小鼠模型测试针对人胰岛的工程化人类Tregs 自身免疫性胰岛炎症。这项研究的成功完成将为未来提供临床前数据 这些策略在临床试验中的实施。

ABSTRACT In type I diabetes, pancreatic islets are destroyed by an autoimmune reaction. Thus, a general strategic goal for preventing islet loss is to locally suppress this autoimmune response, while avoiding systemic immune suppression. FoxP3-expressing T regulatory cells (Tregs) are immune cells that play a central role in local tolerance, and therefore could serve as a potential platform for a cell therapy to prevent islet loss. Tregs have many attractive attributes as a suppressive cell therapy: they can exert dominant immunosuppressive actions, through cell-cell interactions or production of suppressive cytokines; they can in principle be long lived; and tolerance induced by Tregs can persist through infectious tolerance by conferring tolerogenic properties to neighboring cells. In mouse models, single infusion of Tregs can prevent and reverse diabetes indefinitely. The encouraging preliminary data in mouse models have let to the development of ongoing clinical trials of Treg cell therapies in humans. Nonetheless, Treg cell therapy presents several key challenges: it is hard to specifically target them to the islets and avoid systemic suppression, they are hard to expand in sufficient numbers (especially relative to conventional effector T cells), and their cell fate can be changed, especially in particular inflammatory microenvironments. In the past few years, however, there have been remarkable advances in using conventional T cells for cancer therapy (e.g. CAR T cells), including an explosion of new synthetic biology tools that can be used to precisely target T cells to disease tissues, to control their fate and proliferation, and to even give them the capability to locally deliver non-natural therapeutic payloads. Here our goal is to bring these new tools to bear on the problem of engineering improved islet-specific therapeutic suppressive cells. Our aims are to: 1) engineer natural Tregs with improved targeting and recognition of islets 2) develop tools to selectively expand therapeutic Tregs in vivo and enhance their stability 3) design synthetic suppressor cells that disarm effectors, dampen inflammation and promote islet repair These approaches wed cutting-edge synthetic biology with multiple strategies for developing therapeutic suppressor cells. We will establish proof-of-concept data using mouse model of autoimmune diabetes and apply them to test engineered human Tregs targeted to human islets using a humanized mouse model of autoimmune islet inflammation. Successful completion of this study will provide preclinical data for future implementation of these strategies in clinical trials.