Haemophilus Hap-mediated Microcolony Formation

非分型流感嗜血杆菌是引起局部呼吸道疾病的常见原因， 包括中耳炎、鼻窦炎、支气管炎和肺炎。此外，这种生物还会造成严重的 全身性疾病，如脑膜炎、心内膜炎和败血症。发病机制的第一步 非分型流感嗜血杆菌病涉及上呼吸道粘膜的定植。我们已经确定了 一种名为Hap的流感嗜血杆菌丝氨酸蛋白酶，它有助于与上皮细胞和 细胞外基质蛋白，也促进细菌聚集和微集落形成。基于 我们的体外实验结果推测，Hap在定植过程中起着重要作用。HAP属于 到不断增长的自身转运蛋白家族，并被合成为具有3种功能的前体蛋白 结构域，包括N-末端信号序列，具有黏附活性的内部蛋白酶结构域(HAPS)， 和具有转运子活性的C-末端外膜结构域(HapB)。最终，Hap将经历 自身蛋白水解性切割，胞外释放羟基磷灰石。在最近的工作中，我们演示了Hap- 一种称为分泌白细胞的宿主蛋白加强了介导的黏附和微集落形成 蛋白酶抑制物(SLPI)。这种蛋白质存在于呼吸道分泌物中，并抑制Hap的自我蛋白分解， 导致与表面相关的HAPS的积累。在目前的提案中，我们将重点关注Hap中介 黏附和微集落形成。在目标1中，我们将求解Haps的晶体结构，并定义 参与黏附和微集落形成的相互作用表面。在目标2中，我们将考察 以抵抗阳离子多肽的杀伤，逃避巨噬细胞的吞噬，并增强 在栗鼠中耳炎模型中的持久性。在目标3中，我们将描述 呼吸道病毒感染与Hap介导的黏附和微集落形成的集中作用 斯尔皮的。 从实践的角度来看，拟议的研究可能有助于努力制定新的战略 流感嗜血杆菌病的治疗和预防。也许更重要的是，他们可能会提供一般 深入了解宿主-微生物的关系，并扩大我们对微生物生物膜的理解。

Nontypable Haemophilus influenzae is a common cause of localized respiratory tract disease, including otitis media, sinusitis, bronchitis, and pneumonia. In addition, this organism causes serious systemic disease, such as meningitis, endocarditis, and septicemia. The initial step in the pathogenesis of nontypable H. influenzae disease involves colonization of the upper respiratory mucosa. We have identified an H. influenzae serine protease called Hap, which facilitates intimate interaction with epithelial cells and extracellular matrix proteins and also promotes bacterial aggregation and microcolony formation. Based on our in vitro results, we speculate that Hap plays an important role in the process of colonization. Hap belongs to the growing family of autotransporter proteins and is synthesized as a precursor protein with 3 functional domains, including an N-terminal signal sequence, an internal protease domain with adhesive activity (Haps), and a C-terminal outer membrane domain with translocator activity (HapB). Ultimately, Hap undergoes autoproteolytic cleavage, with extracellular release of Haps. In recent wor k, we demonstrated that Hap- mediated adherence and microcolony formation are potentiated by a host protein called secretory leukocyte protease inhibitor (SLPI). This protein is present in respiratory secretions and inhibits Hap autoproteolysis, resulting in accumulation of surface-associated Haps. In the present proposal, we will focus on Hap-mediated adherence and microcolony formation. In Aim 1, we will solve the crystal structure of Haps and define the interactive surfaces involved in adherence and microcolony formation. In Aim 2, we will examine the ability of microcolonies to resist killing by cationic peptides, to evade macrophage phagocytosis, and to enhance persistence in the chinchilla otitis media model. In Aim 3, we will characterize the relationship between respiratory viral infection and Hap-mediated adherence and microcolony formation, concentrating on the role of SLPI. From a practical perspective, the proposed studies may facilitate efforts to develop novel strategies for the treatment and prevention of H. influenzae disease. Perhaps more importantly, they may provide general insights into host-microbe relationships and expand our understanding of microbial biofilms.