Rhinovirus-Induced Chemokine Production and Asthma

病毒性呼吸道感染是急性加重的主要原因，最常涉及的病毒是鼻病毒（RV）。 RV诱导的白细胞介素-8（IL-8）和RANTES的产生与细胞炎症、普通感冒症状的严重程度和气道高反应性的变化密切相关。 总之，这些表明，这些趋化因子在下气道中通过对嗜中性粒细胞和淋巴细胞炎症的影响而失调，是导致气道阻塞和哮喘的主要因素。 为建立RV复制诱导趋化因子产生的机制而进行的初步实验表明，RV双链RNA（dsRNA）和双链RNA依赖性蛋白激酶（PKR）的激活是增加上皮细胞产生IL- 8和RANTES的关键事件。 基于这些发现，我们假设PKR和RV 3C蛋白酶的dsRNA活化刺激特异性信号级联[核因子κ B（NF-κ B）;促分裂原活化蛋白激酶（MAPK），CCAAT/增强子结合蛋白β（C/EBP β）]，其促进上皮细胞转录IL-8和RANTES。 此外，在哮喘中存在对该过程的调节的损失，从而导致这些趋化因子的失调产生，以及增加的气道炎症和哮喘。 为了验证这些假设，我们建议确定双链RNA对RANTES和IL-8基因转录的影响，并选择调节这一过程的转录因子，在非转化的支气管上皮（BE）细胞。 此外，将确定3C蛋白酶对阻遏蛋白Oct-1的切割和IL-8转录的上调的影响。 最后，我们建议评估来自正常和哮喘志愿者的BE细胞中趋化因子产生和调节的差异。 总之，这些研究将RV复制周期中的特定事件和蛋白质与促炎趋化因子的产生联系起来，并确定哮喘对这些过程的影响。 通过实现这些目标，拟议的研究将产生有关病毒诱导的儿童哮喘急性发作的发病机制的额外信息，从而为遗传分析和更有效的治疗策略确定新的靶点。

Viral respiratory infections are the major cause of acute exacerbations, and the virus most often implicated is rhinovirus (RV). RV induced production of interleukin-8 (IL-8) and RANTES correlates closely with cellular inflammation, the severity of common cold symptoms, and changes in airway hyperresponsiveness. Together, these suggest that dysregulation of these chemokines in the lower airway, through effects on neutrophilic and lymphocytic inflammation, is a major factor in causing airway obstruction and asthma. Preliminary experiments conducted to establish mechanisms by which RV replication induces the production of chemokines indicate that RV double-stranded RNA (dsRNA) and activation of the double-stranded RNA-dependent protein kinase (PKR) are key events to increase epithelial cell generation of IL- 8 and RANTES. Based upon these findings, we hypothesize that dsRNA activation of PKR and RV 3C protease stimulate specific signaling cascades [nuclear factor kappa-B (NF-kappaB); mitogen- activated protein kinases (MAPK), CCAAT/enhancer-binding protein beta (C/EBPbeta)] that promote transcription of IL-8 and RANTES by epithelial cells. Furthermore, there is a loss in the regulation of this process in asthma, thus leading to dysregulated generation of these chemokines, and increased airway inflammation and asthma. To test these hypotheses, we propose to determine the effects of dsRNA on RANTES and IL-8 gene transcription, and selected transcription factors which regulate this process, in non-transformed bronchial epithelial (BE) cells. In addition, the effects of 3C protease on the cleavage of the repressor protein Oct-1 and upregulation of IL-8 transcription will be determined. Finally, we propose to evaluate differences in chemokine generation and regulation in BE cells derived from normal and asthmatic volunteers. Together, these studies will link specific events and proteins in the RV replication cycle to the generation of pro- inflammatory chemokines, and determine effects of asthma on these processes. By achieving these goals, the proposed studies will yield additional information about the pathogenesis of virus-induced asthma exacerbations in children, and thereby identify new targets for genetic analyses and more effective therapeutic strategies.