Macrophage inflammasome regulation

项目概要/摘要： 先天免疫在肺部防御病原体方面的重要性因最近的发现而得到加强 不同的细胞内病原体识别受体，检测病原体进入细胞质， 巨噬细胞这些受体包括NOD样受体（NLR）以及NOD非依赖性传感器， 如pyrin。细胞内传感器的一个关键功能是它们对半胱天冬酶-1的直接调节 通过一种叫做炎性小体的蛋白质调节复合体。在炎性小体中，NLR和NOD 独立的传感器通过Pyrin结构域（PYD）或半胱天冬酶募集与衔接蛋白ASC相互作用 域（CARD）。这种相互作用诱导半胱天冬酶-1二聚化和自激活。Caspase-1， 激活IL-1β和IL-18的前体，并且活性半胱天冬酶-1也驱动一种形式的细胞死亡， 巨噬细胞和淋巴细胞引起的焦亡这些事件与 炎症性肺病如肺纤维化。然而，尽管《公约》提供了概念上的进步， 炎性小体的发现，即这种复合物是如何组装和控制的，仍然不清楚，限制了我们对它的研究。 对肺部炎症的理解和我们创造新疗法的能力。在这方面，目前 本申请试图通过将其结构和功能与快速炎症反应联系起来， 涉及酪氨酸激酶活性的事件。我们的初步数据表明，pyrin作为一种关键的 炎性小体的组成部分。我们表明，pyrin有能力将酪氨酸激酶带到细胞中。 炎性小体复合物通过其磷酸化调节ASC的功能。因此，我们假设， 这些与芘相关的活性可以通过磷酸化促进ASC和caspase-1之间的相互作用 在ASC的CARD结构域中的保守酪氨酸内。此外，我们还发现， 巨噬细胞与炎性巨噬细胞的不同之处在于它们的pyrin的相对表达。 利用这些关键发现，该项目提出了以下具体目标：1）剖析 2）确定Pyrin在调节ASC中的作用 磷酸化依赖的人炎性小体活化;和3）揭示调节炎症的关键途径。 通过比较驻留的人肺泡巨噬细胞和来自肺结核患者的巨噬细胞的caspase-1活化， 特发性肺纤维化（IPF）的差异，在pyrin和ASC依赖性炎性体信号传导事件。 该项目的成功完成表明有希望为炎症提供新的治疗靶点。 肺部疾病

Project Summary/Abstract: Innate immunity’s importance in lung defense against pathogens has been heightened by the recent discovery of distinct intracellular pathogen recognition receptors that detect pathogen access to the cytosol of macrophages. These receptors include NOD-like receptors (NLRs) as well as NOD independent sensors such as pyrin. A critical function of the intracellular sensors is their direct regulation of the enzyme caspase-1 through a protein regulatory complex called an inflammasome. In an inflammasome, NLRs and NOD independent sensors interact with an adaptor protein ASC via pyrin domains (PYD) or caspase recruitment domains (CARD). This interaction induces caspase-1 dimerization and auto-activation. Caspase-1 then activates the precursors of IL-1β and IL-18, and active caspase-1 also drives a form of cell death of macrophages and lymphocytes known as pyroptosis. These events have been strongly associated with inflammatory lung disorders like pulmonary fibrosis. However, despite the conceptual advances provided by the inflammasome discovery, how this complex is assembled and controlled remains obscure, limiting our understanding of lung inflammation and our ability to create new therapies. In this context, the present application seeks to expand upon the inflammasome hypothesis by linking its structure and function to rapid events that involve tyrosine kinase activities. Our preliminary data point to a role for pyrin as a critical component of inflammasomes. We show that pyrin has the capacity to bring tyrosine kinases to the inflammasome complex to modulate ASC’s function via its phosphorylation. We therefore hypothesize that these pyrin-affiliated activities can promote interactions between ASC and caspase-1 via phosphorylations within conserved tyrosines in the CARD domains of ASC. Furthermore, we have found that resident alveolar macrophages differ from inflammatory macrophages in accordance with their relative expressions of pyrin. Utilizing these key discoveries, the project proposes the following specific aims, 1) to dissect the role of phosphorylation in ASC inflammasome regulation; 2) to determine pyrin’s role in modulating ASC phosphorylation dependent human inflammasome activation; and 3) to uncover critical pathways regulating caspase-1 activation by comparing resident human alveolar macrophage and macrophages from patients with idiopathic pulmonary fibrosis (IPF) for differences in pyrin and ASC dependent inflammasome signaling events. The successful completion of this project shows promise to provide new treatment targets for inflammatory lung disorders.