PDL1-based rAAV-mediated gene therapy for mouse T1D

描述（由申请人提供）：PD-1/PDL-1信号转导已被证明是活化T细胞功能的关键调节因子。PD-L1与PD-1的结合下调效应T细胞增殖和细胞因子产生，并诱导T细胞周期停滞和凋亡或促进产生IL-10的调节性T细胞应答。然而，很少有人知道的作用，PDL 1相关的信号在T细胞反应的β-细胞抗原和T1 D过程。最近的研究表明，NOD小鼠在APC上缺乏PDL 1的表达，PDL 1的胰岛特异性转基因表达显著减少了NOD小鼠的胰岛炎并预防了糖尿病，并且阻断PD-1/PDL 1信号传导的治疗迅速地促使了年轻NOD小鼠的糖尿病发作。我们的初步研究表明，激动剂PDL 1-Ig抑制自发性Th 1应答的p-细胞抗原，逮捕糖尿病致T细胞周期在体外，和治疗与PDL 1-Ig延迟发病的过继转移T1 D在体内。此外，用重组腺相关病毒（rAAV）-PDLI-Ig而不是rAAV-Ig转导的同基因胰岛移植延长了糖尿病NOD小鼠中的胰岛移植物存活，并且用rAAV-PDL 1-Ig治疗6周龄NOD小鼠诱导了PDL 1-Ig的稳定表达，抑制了疾病进展，这与自发性T细胞自身免疫的抑制有关。因此，我们假设用rAAV-PDL 1-Ig治疗以诱导PDL 1-Ig稳定表达可以抑制效应T细胞和/或诱导调节性T细胞应答，从而抑制NOD小鼠中晚期前T1 D的疾病进展并逆转T1 D。我们选择使用AAV作为载体来将PDL 1-Ig或对照IG基因递送到NOD小鼠，因为AAV是非致病性病毒并且几乎没有免疫原性，使得其对于临床应用具有吸引力。AAV可以有效地感染广泛类型的细胞，导致靶基因的长期表达。在该提议中，我们将检查在自身免疫过程的晚期用rAAV-PDL 1-Ig治疗对NOD小鼠中疾病进展和对新糖尿病逆转的影响，并确定PDL 1相关信号传导对NOD小鼠中T细胞自身免疫过程的作用的潜在机制。我们的研究将解决有关PD-1/PDL 1信号对自身免疫性T细胞应答的调节功能的基本问题。我们的研究结果可能为抑制/逆转人类T1 D的新型免疫疗法提供基础。Layperson的摘要：我们将集中在检查T细胞自身免疫的工程抑制剂对小鼠模型中1型糖尿病的抑制/逆转的治疗效果。我们的研究结果可能为T1 D患者的特异性免疫治疗设计提供依据。

DESCRIPTION (provided by applicant): The PD-1/PDL-1 signaling has been shown to be a crucial regulator for activated T cell function. Engagement of the PD-1 by PD-L1 down-regulates effector T cell proliferation and cytokine production, and induces T cell cycle arrest and apoptosis or promotes IL-10-producing regulatory T cell responses. However, little is known the role of PDL1 -related signaling in T cell responses to (3-cell antigens and the T1D process. Recent studies have shown that NOD mice are deficient in expression of PDL1 on APCs, islet-specific transgenic expression of PDL1 significantly reduced insulitis and prevented diabetes in NOD mice, and treatment with blockade for PD-1/PDL1 signaling rapidly precipitated diabetes onset in young NOD mice. Our preliminary studies showed that agonistic PDL1-lg inhibited spontaneous Th1 response to p-cell antigens, arrested diabetogenic T cell cycling in vitro, and treatment with PDL1-lg retarded the onset of adoptively transferred T1D in vivo. In addition, transplantation with syngenic islets transduced by recombinant adeno-associated virus (rAAV)-PDLI-lg, but not rAAV-lg, prolonged islet-graft survival in diabetic NOD mice and treatment of 6 weeks old NOD mice with rAAV-PDL1-lg induced stable expression of PDL1-lg, inhibited disease progression, associated with inhibition of spontaneous T cell autoimmunity. Hence, we hypothesize that treatment with rAAV-PDL1-lg to induce PDL1-lg stable expression may inactivate effector T cells and/or induce regulatory T cell responses, inhibiting disease progression at advanced pre-T1D and reverse T1D in NOD mice. We choose to use AAV as the vector to deliver PDL1-lg or control Ig genes to NOD mice because AAV is a non-pathogenic virus and has little immunogenicity, making it attractive for clinical applications. AAV can effectively infect broad types of cells, leading to a long-term expression of target genes. In this proposal, we will examine the effect of treatment with rAAV- PDL1-lg at the late stage of autoimmune process on disease progression and on reversal of newly diabetes in NOD mice and determine the mechanism(s) underlying the action of PDL1-related signaling on the process of T cell autoimmunity in NOD mice. Our studies will address fundamental questions concerning the regulatory function of PD-1/PDL1 signaling on autoimmune T cell responses. Our findings may provide the basis for novel immunotherapies for the inhibition/reversal of T1D in human. Layperson's abstract: We will center on examining the therapeutic effect of an engineered inhibitor for T cell autoimmunity on inhibition/reversal of type 1 diabetes in mouse model. Our findings may provide a basis for the design of specific immunotherapies for T1D patients.