Mechanisms of Inflammation Resolution in Bacterial Endophthalmitis

项目摘要 炎症通常被认为是宿主对入侵病原体或组织损伤的有益反应。 然而，长期的炎症可能是破坏性的和不适应的，导致不可逆转的损害 精致的纸巾。因此，理想的治疗方法是处理炎症敏感组织，如 视网膜，应该包括免疫调节治疗，以促进炎症的快速消退和 组织内稳态的恢复，以最大限度地减少二次宿主介导的损害。最近，支持决议的人- 使用专门的亲解析调解器(SPM)的基于策略已经显示出巨大的潜力 治疗多发性炎症性疾病。我们发现玻璃体内注射解决素D 1(RvD 1)， 细菌(金黄色葡萄球菌)感染的小鼠眼睛中的一种SPM，可减缓眼内炎的发展， 由于炎症和组织损伤显著减少，并保留了视网膜功能，强调 RvD1介导的前分辨信号在眼内炎中的重要性。然而出乎意料的是，我们 发现RvD1治疗未能保护Toll样受体2(TLR2)基因敲除小鼠的眼睛 葡萄球菌性眼内炎。此外，我们观察到TLR2与RvD1受体的直接相互作用， 脂氧素A4/甲酰肽受体2(ALX/FPR2，简称FPR2)。这引出了一个有趣的基本原理 问题是，诱导炎症消退的分子或信号通路是否与 其他途径，如促进炎症诱导的TLRs。因此，根据先前的研究， 和我们的初步数据，我们假设RvD1介导的保护性先天反应在细菌 眼内炎依赖于TLR2信号。这将以三个具体目标进行测试。AIM-1将 破译RvD1诱导细菌性眼内炎先天保护性反应的机制。 这将通过使用RvD1介导的FPR2信号的药物抑制剂以及 利用FPR2过表达转基因(TG)小鼠和FPR2 KO小鼠。骨髓嵌合研究将 以确定FPR2对居住细胞和髓系细胞的相对贡献。AIM-2将 探讨RvD1和TLR2信号通路在促进炎症消退中的相互作用 眼内炎。这些研究将通过确定1)TLR2缺乏来阐明这种新的串扰 改变Rvd1的生成，2)在什么条件下TLR2和FPR2物理地相互作用，以及3) 这种相互作用对下行信令的影响。AIM-3旨在测试Rvd1作为一种 辅助治疗在减轻眼内炎相关性视力损失中的作用。拟议的实验包括联合- 常规抗生素给药及最佳给药途径的确定 (外用与玻璃体内注射)，并与皮质类固醇的疗效进行比较。我们共同相信， 这份提案中提出的机械性见解和治疗策略可能会对 这一领域不仅与眼内炎有关，而且与其他眼部和非眼部传染病有关。

Project Summary Inflammation is generally considered a beneficial host response towards invading pathogens or tissue injury. Prolonged inflammation, however, can be destructive and maladaptive, leading to irreversible damage to delicate tissues. Thus, the ideal treatment approach when dealing with inflammation-sensitive tissues, such as the retina, should include immunomodulatory therapies to promote the rapid resolution of inflammation and the restoration of tissue homeostasis to minimize secondary host-mediated damage. Recently, pro-resolution- based strategies using specialized pro-resolving mediators (SPMs) have shown great potential for the treatment of multiple inflammatory diseases. We show that the intravitreal administration of resolvin D1 (RvD1), a type of SPM, in bacterial (S. aureus)-infected mouse eyes attenuated the development of endophthalmitis, with drastically reduced inflammation and tissue damage and preserved retinal function, underline the importance of RvD1-mediated pro-resolving signaling in endophthalmitis. However, unexpectedly, we discovered that RvD1 treatment failed to protect the eyes of Toll-like receptor 2 (TLR2) knockout mice from staphylococcal endophthalmitis. Moreover, we observed a direct interaction of TLR2 with the RvD1 receptor, lipoxin A4/formyl peptide receptor 2 (ALX/FPR2, referred as FPR2). This raises an interesting fundamental question, whether the molecule or signaling pathways that induce the resolution of inflammation interact with other pathways such as the TLRs, which promote the induction of inflammation. Thus, based on prior studies and our preliminary data, we hypothesize that RvD1-mediated protective innate responses in bacterial endophthalmitis are dependent on TLR2 signaling. This will be tested with three specific aims. Aim-1 will decipher the mechanisms underlying RvD1-induced protective innate responses in bacterial endophthalmitis. This will be accomplished by using pharmacological inhibitors of RvD1-mediated FPR2 signaling, as well as the use of FPR2 overexpressing transgenic (Tg) mice and FPR2 KO mice. Bone marrow chimeric studies will be performed to determine the relative contribution of FPR2 on residential vs. myeloid cells. Aim-2 will investigate the interplay of the RvD1 and TLR2 signaling pathways in promoting inflammation resolution in endophthalmitis. These studies will elucidate this novel cross-talk by determining 1) whether TLR2 deficiency alters the generation of RvD1, 2) under which conditions TLR2 and FPR2 interact physically, and 3) the consequences of this interaction on downstream signaling. Aim-3 is designed to test the efficacy of RvD1 as an adjunct therapeutic in mitigating endophthalmitis-associated vision loss. Proposed experiments include the co- administration of RvD1 with conventional antibiotics and the determination of the optimal route of delivery (topical vs. intravitreal) and a comparison of its efficacy with that of corticosteroids. Together, we believe that the mechanistic insights and the treatment strategies developed in this proposal could have a major impact on the field, not only with regards to endophthalmitis but other ocular and non-ocular infectious diseases as well.