Combinatorial Beta Cell-Specific Cytokine Therapy to Reverse Type I Diabetes

描述（由申请人提供）：1型糖尿病（T1D）是一种T细胞介导的自身免疫性疾病，其特征是朗格汉斯胰岛中产生胰岛素的ß细胞被破坏。在NOD小鼠等啮齿动物模型中，胰岛内免疫调节受损会导致T1D，在人类中也很可能如此。在NOD小鼠中，糖尿病发病的特征是：1)致病性T细胞和促炎抗原呈递细胞大量浸润胰岛，2)表达Foxp3的免疫调节性T细胞（Foxp3+Treg）减少，3)ß细胞质量损失80-90%。人类T1D患者胰岛炎症的性质和影响因素似乎更加多变。研究报告称，尸体T1D胰腺大量浸润T细胞，但也观察到有显著残余ß细胞团块的受试者，在某些情况下，未检测到胰岛浸润。我们建议直接控制胰岛炎症环境将被证明是广泛治疗T1D“亚群”的最有效策略。最近，我们证明了通过腺相关病毒（AAV）载体基因传递靶向IL-2在体内β细胞中的表达，可以抑制NOD小鼠的晚期临床前T1D。这种保护是由于Foxp3+Treg的胰岛特异性扩增和增强的抑制功能。重要的是，IL-2的表达定位于胰岛，从而避免了与IL-2等强效、多效细胞因子的全身递送相关的不必要的并发症。目前的申请建议使用AAV载体在胰岛中共表达抗炎细胞因子，以促进协同效应，从而实现强大的免疫调节。目的1将侧重于确定在新近发病的糖尿病NOD小鼠中通过组合ß细胞特异性细胞因子表达诱导的协同作用机制。目的2将利用人源化小鼠，探讨异位细胞因子表达对组织驻留的人效应T细胞和FOXP3+Treg的体内影响。人类胰岛同种异体移植模型也被用来直接建立ß细胞特异性细胞因子表达对抑制人类胰岛病理的功效。该建议的基本假设是Foxp3+Treg受非冗余细胞因子信号的调节，这些信号协同作用以增强内稳态、适应性和功能。同样，多种细胞因子信号事件协同作用介导苔麸耐受性的不同机制。因此，联合抗炎细胞因子用于免疫治疗将诱导更好的、质量上不同的免疫调节。这一建议将促进我们对细胞因子如何相互作用以调节Foxp3+Treg免疫生物学和Teff致病性的一般理解。

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease characterized by the destruction of the insulin producing ß cells found in the pancreatic islets of Langerhans. Impaired immunoregulation within the islets contributes to T1D in rodent models such as NOD mice, and very likely in humans. In NOD mice, onset of diabetes is marked by: i) heavy infiltration of the islets by pathogenic T cells and proinflammatory antigen presenting cells, ii) a diminished pool of islet Foxp3-expressing immunoregulatory T cells (Foxp3+Treg), and iii) the loss of 80-90% of ß cell mass. The nature and effectors of islet inflammation in human T1D appear to be more variable. Studies have reported cadaveric T1D pancreases being heavily infiltrated with T cells, but subjects with significant residual ß cell mass and in some instances, no detectable islet infiltration, have als been observed. We propose that directly manipulating the islet inflammatory milieu will prove to be the most effective strategy to broadly treat "subsets" of T1D. Recently, we demonstrated that late preclinical T1D is suppressed in NOD mice by targeting IL-2 expression to ß cells in vivo via adeno-associated virus (AAV) vector gene delivery. Protection was due to islet-specific expansion of Foxp3+Treg with enhanced suppressor function. Importantly, IL-2 expression was localized to the islets thereby avoiding the unwanted complications associated with systemic delivery of a potent, pleiotropic cytokine such as IL-2. The current application proposes to use AAV vectors to co-express anti-inflammatory cytokines in the islets to promote a synergistic effect leading to robust immunoregulation. Aim 1 will focus on defining mechanisms of synergy induced via combinatorial ß cell-specific cytokine expression in recent onset diabetic NOD mice. Aim 2 will explore the in vivo effects of ectopic cytokine expression on tissue-resident human effector T cells and FOXP3+Treg using humanized mice. A human islet allograft model is also being exploited to directly establish the efficacy of ß cell-specific cytokine expression on suppressing human islet pathology. The underlying hypothesis for this proposal is that Foxp3+Treg are regulated by non-redundant cytokine signals that together act synergistically to enhance homeostasis, fitness and function. Similarly, multiple cytokine signaling events synergize to mediate distinct mechanisms of Teff tolerance. Therefore combining anti-inflammatory cytokines for the purpose of immunotherapy will induce superior and qualitatively distinct immunoregulation. This proposal will advance our general understanding of how cytokines interact to regulate Foxp3+Treg immunobiology and Teff pathogenicity.