Haemophilus Hap-mediated Microcolony Formation

嗜血杆菌 Hap 介导的微菌落形成

• 批准号: 6690982
• 负责人: Joseph W. St. Geme
• 金额: $ 26.78万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6690982
• 关键词: Haemophilus; Hap; mediated; Microcolony; Formation

DESCRIPTION (provided by applicant): 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 (HapBeta). Ultimately, Hap undergoes autoproteolytic cleavage, with extracellular release of Haps. In recent work, we demonstrated that Hap mediated adherence and microcolony formation are potentiated by a host protein called secretory leukocyteprotease 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 forthe 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.

描述（由申请人提供）：不可分型流感嗜血杆菌是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，这种微生物还会引起严重的全身性疾病，例如脑膜炎、心内膜炎和败血症。不可分型流感嗜血杆菌疾病发病机制的第一步涉及上呼吸道粘膜的定植。我们已经鉴定出一种名为 Hap 的流感嗜血杆菌丝氨酸蛋白酶，它促进与上皮细胞和细胞外基质蛋白的密切相互作用，还促进细菌聚集和微菌落形成。根据我们的体外结果，我们推测 Hap 在定植过程中发挥着重要作用。 Hap 属于不断发展的自转运蛋白家族，被合成为具有 3 个功能域的前体蛋白，包括 N 端信号序列、具有粘附活性的内部蛋白酶结构域 (Haps) 和具有转运蛋白的 C 端外膜结构域活动（HapBeta）。最终，Hap 经历自蛋白水解裂解，并释放 Haps 到细胞外。在最近的工作中，我们证明了 Hap 介导的粘附和小集落形成是由一种称为分泌性白细胞蛋白酶抑制剂 (SLPI) 的宿主蛋白增强的。该蛋白存在于呼吸道分泌物中并抑制 Hap 自身蛋白水解，导致表面相关 Hap 的积累。在本提案中，我们将重点关注 Hap 介导的粘附和小集落形成。在目标 1 中，我们将解决 Haps 的晶体结构并定义参与粘附和微菌落形成的交互表面。在目标 2 中，我们将检查小菌落抵抗阳离子肽杀伤、逃避巨噬细胞吞噬作用以及增强龙猫中耳炎模型中持久性的能力。在目标 3 中，我们将描述呼吸道病毒感染与 Hap 介导的粘附和小菌落形成之间的关系，重点关注 SLPI 的作用。 从实践的角度来看，拟议的研究可能有助于制定治疗和预防流感嗜血杆菌疾病的新策略。也许更重要的是，它们可以提供对宿主-微生物关系的一般见解，并扩大我们对微生物生物膜的理解。