Engineered tolerogenic exosomes for treating type 1 diabetes autoimmunity

项目摘要/摘要 该项目的目标是设计一种基于外切体的治疗平台来中和胰腺 β细胞自身免疫作为治疗或预防1型糖尿病(T1D)的策略。我们假设外显体 可以提供几乎无限的纳米颗粒、无细胞MHC复合抗原， 适当的免疫负性调节，可诱导抗原特异性耐受β细胞自身反应性T细胞 而不会影响整个系统的免疫力。 Exosome是一种小的(30-150 nm)生物活性的膜泡，由大多数类型的细胞分泌。 胞外体膜由脂双层组成，具有许多富含胆固醇的脂筏， 鞘磷脂和神经酰胺，使它们在体内具有较长的循环半衰期和延长的保质期。外切体 具有免疫刺激或免疫调节功能。抗原提呈细胞分泌大量的 富含MHC多肽复合体和黏附分子ICAM-1的外体，使它们能够相互作用 直接与T细胞共同控制免疫结果。一般说来，颗粒抗原，如与 胞外体，比可溶性的单体抗原免疫效力强得多。 我们的假设和目标将通过以下目标的实现来检验： ·目标1将确定可以通过改造外切体来过度表达免疫调节分子 程序性死亡配体1(PD-L1)，并可通过该分子和天然MHC负载 在体外以抗原特异的方式抑制激活的T细胞的多肽抗原。 ·Aim 2将在小鼠模型中评估耐受性外切体的体内表现和机制 自身免疫性糖尿病。 尽管人们对T1D的发病机制有越来越多的了解，但T1D在美国的患病率仍在继续上升 和疾病的自然病史，以及更好的治疗选择。因此，有很大的需要 一种根治性疗法，通过与 自身反应性T细胞。这一提议的关键要素是将多聚体、外周体结合的PD-L1定向到 以抗原特异性的方式抑制致糖尿病的T细胞，从而在不影响自身反应性的情况下解决自身反应 系统免疫力。 用友生物医学工程部与用友糖尿病共享的培训环境 研究所提供了独特的合作机会，并接受这两种生物材料领域领导者的专家建议 和T1D自身免疫性。培训目标将通过每周与领先的研究人员一起参加研讨会来实现 来自全国各地的生物材料和T1D，通过学院提供专业发展研讨会 医学院、医学院内分泌学大班和周刊俱乐部。

Project Summary / Abstract The objective of this project is to engineer an exosome-based therapeutic platform to counteract pancreatic beta-cell autoimmunity as a strategy to treat or prevent type 1 diabetes (T1D). We hypothesize that exosomes can provide a virtually unlimited source of nanoparticulate, cell-free MHC-complexed antigen that, alongside appropriate negative regulators of immunity, can induce antigen-specific tolerance to beta cell autoreactive T cells without compromising system-wide immunity. Exosomes are small (30-150nm) biologically active membrane vesicles secreted by most cell types. Exosomal membranes are composed of a lipid bilayer with many lipid rafts that are enriched in cholesterol, sphingomyelin, and ceramide, giving them a long circulatory half-life in vivo and an extended shelf life. Exosomes can display immunostimulatory or immunoregulatory functions. Antigen presenting cells secrete large numbers of exosomes enriched in MHC peptide complexes and the adhesion molecule ICAM-1, enabling them to interface directly with T cells to control immune outcomes. In general, particulate antigen, such as that associated with exosomes, is far more immunologically potent than soluble, monomeric antigen. Our hypothesis and objective will be tested through performance of the following aims: • Aim 1 will establish that exosomes can be engineered to overexpress the immunoregulatory molecule programmed death-ligand 1 (PD-L1) and can act through this molecule and native MHC loaded with peptide antigen to suppress activated T cells in an antigen specific manner in vitro. • Aim 2 will evaluate the in vivo performance and mechanisms of tolerogenic exosomes in a mouse model of autoimmune diabetes. The prevalence of T1D in the U.S. continues to increase, despite growing knowledge of the pathogenesis and natural history of the disease, as well as better treatment options. Therefore, there is a significant need for a curative therapy that addresses the underlying autoimmune aspects of the disease by interfacing with autoreactive T cells. The key element of this proposal is directing multimeric, exosome-bound PD-L1 in an antigen specific manner to suppress diabetogenic T cells, thus addressing autoreactivity without compromising systemic immunity. The training environment shared between the UF Biomedical Engineering department and the UF Diabetes Institute allows for unique opportunities to collaborate and receive expert advice from leaders in both biomaterials and T1D autoimmunity. Training goals will be met by attending weekly seminars with leading researchers in biomaterials and T1D from around the country, professional development seminars offered through the College of Medicine, College of Medicine Endocrinology Grand Rounds, and weekly journal clubs.