Biology of the HMW1 and HMW2 Adhesins of H. Influenzae

流感嗜血杆菌 HMW1 和 HMW2 粘附素的生物学

• 批准号: 7850275
• 负责人: Joseph W. St. Geme
• 金额: $ 14.49万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-17 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7850275
• 关键词: Acute; Adherence; Anabolism; Bacteria; Bacterial Adhesins; Base Pairing; Biology; Bronchitis; Carbohydrates; Chemical Structure; Chinchilla (genus); Collection; Conserved Sequence; Development; Disease; Environment; Enzymes; Epithelial Cells; Epithelium; Escalator; Family; Galactose; Gene Expression Regulation; Genes; Glucose; Goals; HMW2 adhesin; Haemophilus influenzae; Hearing; Human; Immune response; Influenza; Language Development; Licensing; Liquid substance; Mannose; Mediating; Microarray Analysis; Modeling; Molecular; Molecular Weight; Mutation; Nontypable Haemophilus influenza; Organism; Otitis Media; Pathogenesis; Pathway interactions; Performance; Phase; Phosphoglucomutase; Play; Pneumonia; Prevention; Process; Protein Glycosylation; Protein Secretion; Proteins; Regulation; Respiratory Mucosa; Respiratory System; Respiratory Tract Diseases; Respiratory tract structure; Role; Schools; Series; Sinusitis; Speech Development; Stretching; Structural Genes; Structure of respiratory epithelium; Surface; Tandem Repeat Sequences; Transferase; Upper respiratory tract; Vaccines; Variant; Work; antimicrobial; base; glycosylation; immunogenicity; improved; insight; interest; member; microbial host; middle ear; novel; pathogen; promoter; research study; response; treatment strategy

DESCRIPTION (provided by applicant): Nontypable Haemophilus influenzae is a common cause of localized respiratory tract disease, especially otitis media, sinusitis, pneumonia, and bronchitis. Following each episode of acute otitis media, fluid remains in the middle ear for weeks to months and is associated with significant hearing deficit, which in turn can impair language acquisition, speech development, and school performance. The initial step in the pathogenesis of disease due to nontypable H. influenzae involves colonization of the upper respiratory epithelium. We have demonstrated that two related high-molecular-weight proteins called HMW1 and HMW2 promote attachment to human epithelium, an essential step in the process of colonization. Of note, HMW1- and HMW2-1ike proteins are present in 75-80% of all nontypable H. influenzae strains. In recent work, we have established that the HMW1 and HMW2 proteins are variant members of the autotransporter family and are glycosylated. Based on studies with HMW1, glycosylation requires a protein called HMW1C and a phosphoglucomutase involved in LOS biosynthesis. In addition, we have discovered that expression of HMW1 and HMW2 is phase variable, enabling the organism to adapt to diverse environments and evade the host immune response. In the present proposal we plan to elucidate the molecular details of HMW1 and HMW2 glycosylation. In particular, we will define the chemical structure of the carbohydrate modifying HMW1 and HMW2, the biosynthetic pathway involved in glycosylation of HMW 1 and HMW2, and the relationship between glycosylation and immunogenicity. In additional experiments, we will elucidate the mechanism by which expression of HMW1 and HMW2 is regulated, focusing in particular on the function of 7-base pair tandem repeats that lie within the promoters of the HMW1 and HMW2 structural genes and undergo spontaneous variation in number. We will also examine the role of a conserved 19-base pair sequence that is upstream of the repeats in the promoters of the HMW1 and HMW2 structural genes and upstream of the hmwB and hmwC genes. Finally, using microarray technology, we will identify H. influenzae genes that are activated by HMW1/HMW2-mediated adherence, then assess the effect of these genes in the chinchilla otitis media model. From a practical perspective, the results of these studies may be directly relevant to the development of novel antimicrobials and a licensed vaccine effective in the treatment and prevention of nontypable H. influenzae disease. More generally, they may provide fundamental insights into host-microbial relationships, protein secretion, protein glycosylation, and gene regulation.

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，尤其是中耳炎、鼻窦炎、肺炎和支气管炎。每次急性中耳炎发作后，液体会在中耳中滞留数周至数月，并导致严重的听力缺陷，进而损害语言习得、言语发展和学校表现。不可分型流感嗜血杆菌引起的疾病发病机制的第一步涉及上呼吸道上皮的定植。我们已经证明，两种相关的高分子量蛋白（HMW1 和 HMW2）可促进与人类上皮细胞的附着，这是定植过程中的一个重要步骤。值得注意的是，HMW1 和 HMW2-1 样蛋白存在于 75-80% 的所有不可分型流感嗜血杆菌菌株中。在最近的工作中，我们已经确定 HMW1 和 HMW2 蛋白是自转运蛋白家族的变体成员并且被糖基化。根据 HMW1 的研究，糖基化需要一种名为 HMW1C 的蛋白质和一种参与 LOS 生物合成的磷酸葡萄糖变位酶。此外，我们发现HMW1和HMW2的表达是阶段可变的，使生物体能够适应不同的环境并逃避宿主的免疫反应。在本提案中，我们计划阐明 HMW1 和 HMW2 糖基化的分子细节。特别是，我们将定义修饰HMW1和HMW2的碳水化合物的化学结构、参与HMW 1和HMW2糖基化的生物合成途径，以及糖基化与免疫原性之间的关系。在其他实验中，我们将阐明 HMW1 和 HMW2 表达的调节机制，特别关注位于 HMW1 和 HMW2 结构基因启动子内并在数量上发生自发变化的 7 碱基对串联重复的功能。 。我们还将检查位于 HMW1 和 HMW2 结构基因启动子重复序列上游以及 hmwB 和 hmwC 基因上游的保守 19 碱基对序列的作用。最后，利用微阵列技术，我们将鉴定由 HMW1/HMW2 介导的粘附激活的流感嗜血杆菌基因，然后评估这些基因在龙猫中耳炎模型中的作用。从实践的角度来看，这些研究的结果可能与新型抗菌药物和有效治疗和预防不可分型流感嗜血杆菌疾病的许可疫苗的开发直接相关。更一般地说，它们可以提供对宿主-微生物关系、蛋白质分泌、蛋白质糖基化和基因调控的基本见解。