Defining the Role of Regulatory T Cells in Resolution of Acute Lung Injury

项目摘要 关于肺是如何从急性呼吸窘迫综合征中恢复的，我们所知的信息很少。 (ARDS)和肺炎，这种知识差距导致了发病率和死亡率持续居高不下 这些疾病。免疫细胞的一个亚群，Foxp3+调节性T淋巴细胞(Tregs)被认为是重要的 在几种急性肺损伤(ALI)的实验模型中的分辨率。此外，Tregs还存在于 ARDS患者的肺，提示它们有助于ARDS的恢复。树突状细胞可以来自胸腺或胸腺 或胸腺外来源。胸腺外，外周诱导的树突状细胞(ITregs)由幼稚的T细胞和 在控制获得性免疫以抑制免疫细胞渗透方面起着独特和基本的作用 支气管壁和细支气管壁。此外，我们发表的研究表明，在肺的解决期 与未受伤的对照相比，受伤的Tregs在数量上扩大并改变其基因表达谱 肺部。Treg转录组图谱确定了几个基因，这些基因揭示了Treg在 阿里决议。从分解的肺组织中分离出的Tregs中有一个转录显著上调23倍的转录本是 基质金属蛋白酶12(MMP12)。重要的是，缺乏内源性Treg并补充了MMP12-/-的小鼠 过继转移的Tregs在消退过程中炎性细胞增加，上皮细胞增殖减少 而不是注射MMP12+/+Treg的小鼠。Treg转录组也表明下调的表达 KDM6B和SIK1这两个调节基因转录的Treg转录本可能具有调节基因转录的功能 Treg归巢、保持、稳定和生存。这些目的是为了验证中心假设，即特雷格是关键的 通过优化Treg响应，ALI的严重程度可以降低，并加速解决。目标 1研究了iTregs在ALI解析过程中的作用。假设iTregs是 内毒素、肺炎链球菌和甲型流感诱导的ALI后炎症和肺修复的最佳解决方案。 Tregs和iTregs的直接作用将通过Tregs和AT2细胞的体外共培养来确定。目标 2确定在ALI消退过程中Treg表达的MMP12的影响。假设是特雷格 MMP12在ALI的表达中起着协调和促进ALI消退的多重作用。底物： 将在BAL液和肺组织中发现Treg MMP12。目标3确定不同监管的 转录本KDM6B和SIK1调节Treg促进的ALI的分解。我们将测试Tregs的假设 KDM6B缺陷会降低Foxp3的表达水平，并延迟、不充分的分解和Tregs SIK1的缺陷提高了分辨率的质量。我们预期拟议的研究将决定 ITregs在ALI的解决中发挥作用，并确定Tregs调节解决和修复的机制。 识别和阐明这些机制将使治疗方法的发展尽可能地减少 附带组织损伤，而不会对损伤的有益反应产生不利影响。

Project Summary There is a paucity of information known about how the lung recovers from acute respiratory distress syndrome (ARDS) and pneumonia, and this knowledge gap has contributed to the continued high morbidity and mortality of these diseases. A subset of immune cells, Foxp3+ regulatory T lymphocytes (Tregs), is thought to be important in resolution in several experimental models of acute lung injury (ALI). Furthermore, Tregs are present in the lung of patients with ARDS, suggesting that they contribute to ARDS recovery. Tregs can arise from either thymic or extra-thymic origins. Extra-thymic, peripherally-induced Tregs (iTregs) are converted from naïve T cells and serve distinct and essential functions in controlling adaptive immunity to restrain immune cell infiltrates in the bronchial and bronchiolar walls. Furthermore, our published studies show that during the resolving phase of lung injury, Tregs expand in number and change their gene expression profiles compared to Tregs in uninjured control lungs. Treg transcriptome profiling identifies several genes that shine a light on novel functions of Tregs during ALI resolution. One transcript that is markedly upregulated 23-fold in Tregs isolated from resolving lung tissue is matrix metalloproteinase 12 (Mmp12). Importantly, mice lacking endogenous Tregs and repleted with Mmp12-/- Tregs by adoptive transfer have elevated inflammatory cells and less epithelial proliferation during resolution than mice repleted with Mmp12+/+ Tregs. The Treg transcriptome also suggests that downregulated expression of Treg transcripts Kdm6b and Sik1, both of which act to regulate gene transcription, may function to regulate Treg homing, retention, stability, and survival. The Aims seek to test the central hypothesis that Tregs are critical to resolution and that by optimizing Treg responses, ALI severity can be reduced, and resolution hastened. Aim 1 investigates the role of iTregs during resolution of ALI resolution. The hypothesis is that iTregs are required for optimal resolution of inflammation and lung repair after ALI induced by LPS, S. pneumoniae, and influenza A. The direct effects of Tregs and iTregs will be determined using in vitro co-cultures of Tregs and AT2 cells. Aim 2 determines the impact of Treg-expressed MMP12 during the resolution of ALI. The hypothesis is that Treg expression of MMP12 exerts multiple roles in orchestrating and facilitating the resolution of ALI. Substrates of Treg MMP12 will be identified in BAL fluid and lung tissue. Aim 3 determines if the differentially regulated transcripts, Kdm6b and Sik1, regulate Treg-promoted resolution of ALI. We will test the hypothesis that Tregs deficient in Kdm6b have decreased Foxp3 expression levels and delayed, inadequate resolution and that Tregs deficient in Sik1 have improved quality of resolution. We anticipate that the proposed studies will determine the roles iTregs play in ALI resolution and identify mechanisms by which Tregs mediate resolution and repair. Identifying and elucidating these mechanisms will allow the development of therapeutic approaches to minimize collateral tissue damage without adversely altering the beneficial response to injury.