Engineered biomaterials modulating inflammatory T cells in rheumatic arthritis

项目总结 免疫耐受是由许多分子和细胞机制介导的，包括调节性T细胞 (Treg)。这种免疫耐受性的崩溃导致衰弱的自身免疫性疾病，其中类风湿性疾病 关节炎(RA)就是典范。与免疫信号相关的等位基因的多态可能会导致 个体对类风湿关节炎的发展有一定的促进作用。蛋白酪氨酸磷酸酶非受体2的遗传变异 (PTPN2)基因座就是这样一组突变，它们被很好地描述为与疾病发病机制有关 和RA严重程度在一组公认的患者中。此更改的信令会导致对 免疫格局，特别是影响抗炎Treg和促- 炎症T辅助17(Th17)细胞参与类风湿关节炎的发展。减小的PTPN2函数结果 在Treg不稳定性中，Treg在炎性关节炎中转化为致病的“Th17样”效应T细胞 微环境，导致自生自灭的严重炎症循环。然而，目前还没有 针对Treg不稳定的治疗以挽救Treg功能和促进免疫稳态来帮助解决 发炎。环糊精/全反式维甲酸络合物(CAC)是一种很有前途的工具，可以满足以下需求 PTPN2单倍体不足(PTPN2+/-)患者恢复和维持Treg功能的临床可翻译疗法 像CAC这样的个体能够防止炎症条件下Treg的不稳定。然而， 对CAC进行系统性管理以促进Treg不是一个可行的策略，因为这可能会带来系统性风险 免疫抑制可能会增加严重感染和癌症的风险。为了解决这个问题，它是 假设CAC在关节处的局部持续输送将增强Treg的稳定性并改善 PTPN2的临床结果损害了内型。实现持久的部位特异性免疫 调制，一种可注射的生物材料系统用于CAC的释放是必要的。这个项目的目标是 (I)开发和表征用于持续输送CAC的可注射生物材料系统；和(Ii)阐明 CAC介导的Treg稳定化的有效性、机制和特异性。这将在以下方面实现 具体目的：目的：1.一种微球制剂(CAC-MP)，该微球由聚乳酸-共聚物包裹的CAC-MP组成. 将对羟基乙酸(PLGA)进行表征和体内释放动力学优化。随后，一次剂量 研究将进行不同剂量的CAC-MP在PTPN2+/-SKG类风湿关节炎模型中的作用。目标 2.阐明CAC-MP改善PTPN_2+/-SKG关节炎的作用机制。 并将检测CAC-MP对全身免疫反应的影响。这个项目的立竿见影的效果 将确定局部免疫调节挽救Treg不稳定以改善预后的可行性 使用经临床批准的材料的明确的RA患者亚组。此外，可注射生物材料 本文开发的平台将具有更广泛的适用性，作为一种工具来调节局部免疫调节和 可用于探讨免疫耐受和耐受破坏的问题。

PROJECT SUMMARY Immune tolerance is mediated via a number of molecular and cellular mechanisms, including regulatory T cells (Treg). Breakdown of this immune tolerance leads to debilitating autoimmune disease, of which rheumatoid arthritis (RA) is exemplary. Polymorphisms in alleles associated with immune signaling can predispose individuals to the development of RA. Genetic variants at the protein tyrosine phosphatase non-receptor 2 (PTPN2) locus are one such set of mutations that are well characterized to contribute to disease pathogenesis and RA severity in a well-established subset of patients. This altered signaling results in changes to the immunological landscape, and particularly influences the balance between anti-inflammatory Treg and the pro- inflammatory T helper 17 (Th17) cells that are involved in RA development. Diminished PTPN2 function results in Treg instability, in which Treg convert to pathogenic “Th17-like” effector T cells in the inflammatory arthritic microenvironment, leading to self-perpetuating cycle of severe inflammation. However, currently there are no therapies that target Treg instability to rescue Treg function and promote immune homeostasis to help resolve inflammation. Cyclodextrin/all-trans retinoic acid complexes (CAC) are a promising tool to address the need for a clinically translatable therapy to restore and maintain Treg function in PTPN2 haploinsufficient (PTPN2+/-) individuals, as CAC are capable of preventing Treg destabilization in inflammatory conditions. However, the systemic administration of CAC to promote Treg is not a feasible strategy, as this may run the risk of systemic immune suppression that could increase the risk of serious infection and cancer. To address this, it is hypothesized that the local, sustained delivery of CAC at the joint will enhance Treg stability and improve clinical outcomes in the PTPN2 compromised endotype. To achieve prolonged, site specific immune modulation, an injectable biomaterial system for the release of CAC is necessary. The goal of this project is to (i) develop and characterize an injectable biomaterial system for the sustained delivery of CAC and (ii) elucidate the efficacy, mechanisms, and specificity of CAC-mediated Treg stabilization. This will be achieved in the following Specific Aims: Aim 1. A microparticle formulation (CAC-MP) comprising CAC encapsulated by poly (lactic-co- glycolic) acid (PLGA) will be characterized and optimized for in vivo release kinetics. Subsequently, a dosage study will be conducted to examine efficacy of CAC-MP at different doses in the Ptpn2+/- SKG model of RA. Aim 2. The mechanism of action by which CAC-MP mediate improvement in Ptpn2+/- SKG arthritis will be elucidated, and the impact of CAC-MP on systemic immune response will be examined. The immediate results of this project will determine the feasibility of localized immune modulation to rescue Treg instability to improve outcomes in a well-defined subset of RA patients using clinically approved materials. Additionally, the injectable biomaterial platformed developed herein will have broader applicability as a tool to mediate local immune modulation and may be used to probe questions of immune tolerance and tolerance breakdown.