Mechanisms and Consequences of Hyaluronan Production in Asthma

摘要-项目2 在上一个研究周期中，我们确定了原代气道上皮细胞（AEC） 合成重链（HC）修饰透明质酸（HA）顶筏和气道平滑肌细胞（ASMC） 合成HA电缆的细胞外基质，其是白细胞粘附的或我们也称为 病理-HA。我们在该项目中的研究揭示了这种病理性HA基质在肿瘤发生中的重要性。 哮喘的炎症、气道重塑和高反应性。在气道内， 紧密耦合的ASMCs和上覆上皮之间的相互作用，越来越多的数据表明， 上皮细胞和平滑肌细胞通过产生早期的 调解员在项目2的继续中，我们建议研究气道上皮产生NO和 细胞因子通过哮喘中的平滑肌促进病理性HA基质的积累。在 初步数据显示，气道上皮细胞对原型Th 2细胞因子或细胞因子混合物有反应， 与HA的产生和iNOS的诱导有关。利用我们新颖的共培养系统，我们表明， ASMCs可以通过产生白细胞粘附的HA电缆对上皮来源的NO产生应答。我们也 显示HA产生的主要贡献者是通过透明质酸合酶2（HAS 2）。协同 NO调节和信号传导机制的研究，这是由该计划的其他成员研究， 支持我们的实验，以确定病理性HA形成的机制，包括NO代谢（项目 1），特异性蛋白巯基亚硝基化（项目3），和NO激活途径（项目4）。所以针对本 继续，我们建议测试的假设，NO和HC产生的哮喘气道 上皮通过ASMCs促进病理性白细胞粘附HC-HA基质形成， 这些机制似乎是sGC独立的NO识别途径。为了验证这个假设，我们 计划确定导致气道上皮细胞产生HA的途径[目的1]。我们还计划确定 ASMC产生白细胞粘附性HA基质的途径[目的2]。最后，我们将确定 NO和HA对体内炎症、AHR和重塑发展的贡献[目的3]。计划2 取决于项目的协作互动和互补技能、专业知识和资源 来检验假设程序核心支持新型鼠模型、具有技术挑战性的测定， 临床样品，以促进项目2中的转化和机制实验，而不是其他 可能

ABSTRACT - PROJECT 2 During the previous award cycle, we identified mechanisms by which primary airway epithelial cells (AECs) synthesize heavy chain (HC) modified hyaluronan (HA) apical rafts, and airway smooth muscle cells (ASMCs) synthesize an extracellular matrix of HA cables, which are leukocyte-adhesive or what we have also termed as pathologic-HA. Our studies in the Program revealed the importance of this pathologic-HA matrix in the genesis of inflammation, airway remodeling and hyperresponsiveness of asthma. Within the airway, there is constant interaction between the closely coupled ASMCs and overlying epithelium, and increasing data indicate a primary role for epithelium and smooth muscle in the origins of inflammation through production of early mediators. In this continuation of Project 2, we propose to investigate if airway epithelial production of NO and cytokines promotes the accumulation of a pathologic-HA matrix by the smooth muscle in asthma. In preliminary data, we show that the airway epithelium responds to prototypic Th2 cytokines or cytokine mixes with the production of HA and induction of iNOS. Utilizing our novel co-culture system, we show that the ASMCs can respond to epithelial derived NO with the production of leukocyte-adhesive HA cables. We also show that the major contributor to HA production is via the hyaluronan synthase 2 (HAS2). Collaborative studies of NO regulation and signaling mechanisms, which are investigated by other members of this Program, support our experiments to define mechanisms of pathological HA formation, including NO metabolism (Project 1), specific protein thiol nitrosylation (Project 3), and NO activation pathways (Project 4). Thus, in this continuation, we propose to test the hypothesis that NO and HCs produced by the asthmatic airway epithelium promote formation of a pathologic, leukocyte-adhesive HC-HA matrix by ASMCs, through mechanisms that appear to be sGC-independent NO recognition pathways. To test this hypothesis, we plan to identify pathways leading to airway epithelial cell production of HA [Aim 1]. We also plan to identify pathways of ASMC production of a leukocyte-adhesive HA matrix [Aim 2]. Finally, we will determine the contribution of NO and HA on the development of inflammation, AHR, and remodeling in vivo [Aim 3]. Project 2 depends on the collaborative interactions and complementary skills, expertise, and resources of the Program to test hypotheses. Program Cores support novel murine models, technically challenging assays, and shared clinical samples in order to facilitate translational and mechanistic experiments in Project 2 not otherwise possible.