Break Down Barriers: Respiratory epithelial cells as modulators of dendritic cells during the pathogen associated allergic sensitization and acute asthma exacerbation

支气管哮喘是一种慢性呼吸道炎症性疾病。在德国，有400多万人患有哮喘。由于目前的治疗方法主要是以症状为导向，因此需要更好地了解疾病的潜在机制，迫切需要新的治疗方法。在哮喘的发病机制中，呼吸道病毒感染是关键因素，对过敏反应和潜在威胁生命的急性加重的诱发具有巨大影响。呼吸道上皮细胞具有屏障功能和产生粘液的功能，是抵御病原体的第一道防线。如果屏障被打破，上皮细胞就能够分泌几种免疫调节物质，比如警报。因此，它们对早期免疫反应以及树突状细胞(DC)的激活和继而的过继免疫系统印记都有很大的影响。尽管我们知道上皮细胞和免疫系统之间沟通的重要性，但仍然缺乏足够的体外模型来阐明细节。本项目的目的是进一步发展气液界面(ALI)细胞培养技术，使其成为原代人支气管上皮细胞(HBEC)与DC的可重复共培养。在这个模型中，将分析呼吸道合胞病毒(RSV)上皮感染对DC激活和过敏原摄取的影响。除了通过测量呼吸道合胞病毒对上皮细胞的屏障功能、分化或粘液分泌以及分泌的促炎或抗炎分子的组成来分析RSV感染对上皮细胞的直接影响外，还将对其进行表征。我们假设，不同上皮性细胞因子的混合物能够调节和微调DC的中枢功能。这可能会影响哮喘相关的致病过程，如过敏原的摄取和处理，树突状细胞分泌细胞因子，从而激活和启动t细胞反应。这种共培养系统的进一步发展可以克服体外细胞培养缺乏复杂性的主要局限性。这也将有助于减少动物实验。通过独家使用原代人类细胞，该模型包含了很高的翻译能力，并能够在免疫激活的早期阶段识别新的治疗靶点。

Bronchial Asthma is a chronic inflammatory disease of the airways. In Germany, more than 4 million people suffer from Asthma. Since treatment approaches are currently primarily symptom-orientated a better understanding for disease underlying mechanisms is required and new therapeutic approaches are urgently needed. During asthma pathogenesis viral infections of the airways are key players with a huge impact on allergic sensitization and the induction of potentially life-threatening acute exacerbations. With their barrier function and mucus production respiratory epithelial cells are the first line of defence against pathogens. If the barrier breaks, epithelial cells are able to secrete several immunomodulatory substances, like alarmins. Hereby, they have a great impact on the early immune response as well as on dendritic cell (DC) activation and the following imprinting of the adoptive immune system. Despite we know about the importance of communication between epithelial cells and the immune system, adequate in vitro models are still missing to elucidate details. Aim of this project is to further develop air liquid interface (ALI) cell culture techniques to a reproducible co-culture of primary human bronchial epithelial cells (HBEC) and DC. With this model, the impact of epithelial infection with Respiratory Syncytial Virus (RSV) on DC activation and allergen uptake will be analysed. Beside the analysis of direct effects of RSV infection of epithelial cells by measuring its barrier function, differentiation or mucus secretion and the composition of secreted pro- or anti-inflammatory molecules will be characterized. We hypothesise, that the mixture of different epithelial cytokines are able to modulate and fine-tune central functions of DCs. This could influence asthma related pathogenic processes like allergen uptake and processing, cytokine secretion of DCs, and thereby activation and priming of t cell responses. The major limitation of missing complexity of in vitro cell cultures could be overcome by further development of such co-culture systems. This would help to reduce animal experiments as well. By exclusively usage of primary human cells this model contains a high translational capacity and could be able to identify new therapeutic targets during the early phase of immune activation.