HAEMOPHILUS--RAMIFICATIONS OF PILUS MEDIATED ADHERENCE

流感嗜血杆菌是一种广泛的人类疾病的病原体，包括中耳炎、鼻窦炎和肺炎，通常与鼻咽定植密度的增加有关。与其他细菌性呼吸道病原体的情况一样，这一过程的流行病学相关风险因素是与呼吸道病毒感染和环境刺激物(如吸烟)相关的呼吸道粘膜先前损伤。上呼吸道定植是疾病发病机制中的重要事件，细菌粘附素识别真核细胞上的特定受体基序，从而促进上呼吸道定植。血凝毛可能是研究最充分的流感嗜血杆菌粘附素，可由非分型菌株和血清分型菌株表达。我们的初步证据表明，这种结构介导了对受损和挤压的无纤毛呼吸道上皮的黏附。在这一建议中要追求的一个双重假设是，这种微生物毒力因子作用于呼吸道粘膜的受损区域，以应对后续的致病事件，然后通过诱导呼吸道上皮细胞凋亡进一步增强粘膜防御的破裂。以流感嗜血杆菌菌毛为模型系统，我们将利用纤毛/非纤毛同基因菌株和微球连接的菌毛粘附素探针，剖析人呼吸道上皮细胞特异性菌毛受体结构(S)中的多重作用。然后，我们将使用这些工具来表征毛孔受体在重新组织的粘膜表面上的分布动态，以确定这种黏附是否识别与其受体相关的焦点区域，从而导致真核细胞信号转导机制的操纵，增加上皮细胞的凋亡指数，并破坏细胞之间紧密连接的屏障。克服粘液纤毛清除和致病的呼吸道定植的动力学。通过关注这种微生物毒力因子，我们将能够开发出广泛适用的实验系统，这些系统可以用来剖析呼吸道疾病中宿主与病原体相互作用的分子细节。

Haemophilus influenzae is a pathogen that mediates a wide range of human disease including otitis media, sinusitis, and pneumonia often in association with an increased density of nasopharyngeal colonization. As is the case with other bacterial respiratory pathogens, an epidemiologically relevant risk factor for this process is prior injury of the respiratory mucosa associated with respiratory viral infections and environmental irritants (e.g. smoking). Colonization of the upper respiratory tract is an essential event in the pathogenesis of disease and is facilitated by bacterial adhesins that recognize specific receptors motifs on eukaryotic cells. The hemgglutinating pilus is perhaps the most well- studied H. influenzae adhesin and is expressed by both non-typable and serotypable strains. Our preliminary evidence suggests that this structure mediates adherence to damaged and extruding non-ciliated respiratory epithelium. A two-fold hypothesis to be pursued in this proposal is that this microbial virulence factor functions to compromised areas of the respiratory mucosa for subsequent pathogenic events and then further enhances the rupture of mucosal defenses by inducing respiratory epithelial cell apoptosis. Using the H. influenzae pilus as a model system, we will dissect the multiple roles in specific pilus receptor structure(s) on human respiratory epithelium by using piliated/non-piliated isogenic strains and microsphere-linked pilus adhesin probes. We will then use these tools to characterize the dynamics of pilus receptor distribution on a re-organizing mucosal surface to determine whether this adhesion recognizes focal areas associated with its receptor can result in the manipulation of eukaryotic cell signal transduction mechanisms, increases the apoptotic index of epithelial cells, and disrupts the barrier of tight junctions between cells. The dynamics of respiratory colonization to surmount mucociliary clearance and cause disease. By focusing on this microbial virulence factor, we will be able to develop broadly applicable experimental systems that can be used to dissect the molecular details of host-pathogen interactions in respiratory disease.