TLR and Notch Ligand in RSV-induced Disease

描述(申请人提供)：婴儿呼吸道病毒感染可对呼吸道功能产生严重的破坏性影响，但也可能影响儿童和成人的长期肺功能。最常见的呼吸道感染是导致儿童住院的主要原因(90%)是呼吸道合胞病毒(RSV)感染。启动适当的抗病毒反应对于以最小的病理生理反应成功清除这种病原体是强制性的。在目前的提案中，我们将集中于RSV感染的最早免疫反应，包括最初激活树突状细胞(DC)上的Toll样受体(TLRs)，然后上调启动获得性免疫反应的重要指示信号。最近的研究发现，Notch/Notch配体诱导的激活在成熟T细胞的激活和分化中具有深远的作用。树突状细胞表面特异性缺口配体的上调是MyD88依赖的，是成熟T细胞分化的关键步骤。然而，对Notch/Notch配体激活通路在病毒感染过程中产生有效免疫反应的作用知之甚少。我们的假设是，TLR介导的缺口配体Delta-like 4是启动适当免疫反应所必需的，如果没有它，RSV感染就会变得更具致病性，导致免疫环境发生变化。这些研究将通过三个特定的目标来具体解决几个新的机制问题：1)确定在RSV感染过程中TLR诱导的DC激活以获得抗病毒指示信号的关键途径；2)确定Delta-like 4在RSV诱导的免疫反应和肺部病理发展中的作用；3)确定血浆细胞样和传统DC群体在RSV感染中对Delta-like 4的表达和T细胞激活的不同作用。这些单独的具体目标相互独立，但又清楚地结合在一起，每个目标都将满足我们的总体假设。我们将结合对基因敲除小鼠的研究、特异性中和抗体、细胞转移实验以及DC和T淋巴细胞分离，从机制上研究这些观察结果。使用特定的新型试剂和先进的技术将使我们高度集成的研究小组能够以逻辑翻译的方式专门针对这些机制。我们的研究将研究一组被称为Toll样受体(TLRs)的PAMP分子及其与细胞因子、趋化因子和Noch配体的产生相关的细胞信号机制。了解这些重要的信号机制将有助于评估与RSV清除不足有关的疾病期间的变化。

DESCRIPTION (provided by applicant): Respiratory viral infections in infants can have devastating effects acutely on airway function, but may also impact the longterm function of the lung in both children and adults. The most common respiratory infection that is the predominant cause of hospitalization in children (>90%) is respiratory syncytial virus (RSV) infection. The initiation of the proper anti-viral responses is mandatory for successfully clearing this pathogen with minimal pathophysiologic responses. In the present proposal we will focus on the earliest immune responses to RSV infection involving the initial activation of toll- like receptors (TLRs) on dendritic cells (DCs) followed by the upregulation of important instructive signals that initiate the acquired immune responses. Recent findings have identified that notch/notch ligand induced activation has a profound role on the activation and differentiation of mature T cells. The upregulation of specific notch ligands on DCs is MyD88-dependent and provides a critical step in mature T cell differentiation. However, little is known about the role of Notch/notch ligand activation pathways for the generation of effective immune responses during virus infections. Our hypothesis for this proprosal is that TLR-mediated notch ligand delta-like 4 is required for the initiation of the appropriate immune response, and without it RSV infection becomes more pathogenic and results in an altered immune environment. These studies will specifically address several novel mechanistic questions by progressing through 3 specific aims that will 1) determine the critical TLR-induced DC activation pathway during RSV infection for anti-viral instructive signals; 2) identify the role of delta- like 4 in the development of RSV-induced immune responses and pulmonary pathology; 3) determine the differential role of plasmacytoid versus conventional DC populations for the expression of delta-like 4 and T cell activation in RSV infection. Together these individual specific aims, which are independent of one another yet clearly integrated, will each address our overall hypothesis. We will investigate these observations mechanistically using a combination of studies in gene knockout mice, specific neutralizing antibodies, and cell transfer experiments along with DC and T lymphocyte isolation. The use of specific novel reagents and advanced techniques will allow our highly integrated group of investigators to specifically target these mechanisms in a logical translational manner.Our studies will investigate a set of PAMP molecules known as toll-like receptors (TLRs) and their cell signaling mechanisms related to the production of cytokines, chemokines, and notch ligands. Understanding these important signaling mechanisms will allow the assessment of alterations during disease related to a lack of RSV clearance.