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

项目摘要 关于肺如何从急性呼吸窘迫综合征中恢复的信息很少 （ARDS）和肺炎，而这种知识差距导致了持续的高发病率和死亡率 这些疾病。免疫细胞的一个亚群，Foxp 3+调节性T淋巴细胞（Tlymphocytes，Tlymphocytes），被认为是重要的。 在急性肺损伤（ALI）的几种实验模型中，此外，TdR存在于 提示它们有助于ARDS的恢复。胸腺可以来自胸腺或 或胸腺外起源。胸腺外外周诱导的T细胞（iT细胞）由初始T细胞转化而来， 在控制适应性免疫以抑制免疫细胞浸润中起着独特和重要的作用。 支气管和细支气管壁。此外，我们发表的研究表明，在肺的消退阶段， 损伤后，TbR在数量上增加，并与未损伤对照组中TbR相比改变了它们的基因表达谱 肺Treg转录组分析确定了几个基因，这些基因揭示了Treg的新功能， ALI解决方案。一种转录物在从分解的肺组织中分离的TcR中显著上调23倍， 基质金属蛋白酶12（Mmp 12）。重要的是，缺乏内源性T细胞亚群并充满Mmp 12-/- 通过过继转移的甲状腺肿在消退期间炎性细胞升高，上皮细胞增殖较少 与Mmp 12 +/+ THP小鼠相比。Treg转录组也表明下调的表达 Treg转录本Kdm 6 b和Sik 1，两者都起调节基因转录的作用，可能起调节基因转录的作用。 Treg归巢、保留、稳定性和存活。这些目标旨在检验中心假设，即TdR是关键的 并且通过优化Treg应答，可以降低ALI严重程度，并加速消退。目的 1研究了在ALI消退过程中iTIFE的作用。假设是， 脂多糖诱导的急性肺损伤后炎症的最佳解决和肺修复，S.肺炎和甲型流感。 将使用Tclad和AT 2细胞的体外共培养物来确定Tclad和iTclad的直接作用。目的 2确定Treg表达的MMP 12在ALI消退期间的影响。假设Treg MMP 12的表达在协调和促进ALI的解决中发挥多种作用。的底物 将在BAL液和肺组织中鉴定Treg MMP 12。目标3确定差异调节是否 转录本Kdm 6 b和Sik 1调节Treg促进的ALI的消退。我们将检验调节性T细胞的假设 缺乏Kdm 6 b的人Foxp 3表达水平降低，分辨率延迟，分辨率不足， Sik 1的缺陷改善了分辨率的质量。我们预计，拟议的研究将确定 在ALI消退中所起的作用，并确定TdR介导消退和修复的机制。 识别和阐明这些机制将有助于开发治疗方法，以最大限度地减少 附带组织损伤，而不会不利地改变对损伤的有益反应。

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.