Role of epigenetic regulation in the persistence of NTHI during colonization, ascension of the Eustachian tube and chronic otitis media

表观遗传调控在 NTHI 定植、咽鼓管上升和慢性中耳炎持续存在中的作用

• 批准号: 9757743
• 负责人: Kenneth L Brockman
• 金额: $ 15.4万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9757743
• 关键词: Acute; Affect; Affinity; Alleles; Anatomy; Antibodies; Antibody titer measurement; Bacteria; Bacterial Infections; Binding; Biomass; Cells; Child; Childhood; Chinchilla (genus); Chromosomes; Chronic; Clinical; Collection; Computer Simulation; Cues; DNA Modification Methylases; Data; Development; Disease; Enzyme-Linked Immunosorbent Assay; Epigenetic Process; Eustachian Tube; Experimental Models; Expression Profiling; Flow Cytometry; Future; Gene Expression; Gene Expression Regulation; Genes; Genetic; Genetic Transcription; Genome; Goals; Hearing; Host Defense; Human; Immune; Immune response; Immune system; Immunologics; In Vitro; Individual; Infiltration; Knowledge; Language Development; Liquid substance; Mediating; Methods; Methylation; Modeling; Morbidity - disease rate; Mucous Membrane; Nasopharynx; Nontypable Haemophilus influenza; Otitis Media; Pathogenesis; Phase; Phenotype; Population; Prevention strategy; Process; RNA; Recurrence; Regulation; Regulon; Reporting; Research; Research Design; Role; Sampling; Severity of illness; Site; Sterility; System; Treatment Failure; Upper Respiratory Infections; Variant; Viral; Virulence; Virulence Factors; Virus; chemokine; cohort; cytokine; design; epigenetic regulation; hearing impairment; host-microbe interactions; human pathogen; improved; in vivo; middle ear; normal hearing; novel; pathogen; pathogenic bacteria; prevent; promoter; recruit; response; transcriptome; treatment strategy

Project Summary Middle ear infection or otitis media (OM) is the most predominant bacterial disease of childhood and results in significant morbidity in the U.S. and globally. Episodes of OM can substantially affect a child’s ability to hear normally. This loss of hearing is of great concern due to the long-term consequences on language development. Multiple different bacterial species and viruses cause middle ear infections. Nontypeable Haemophilus influenza (NTHI) is the primary bacterial pathogen of chronic OM, recurrent OM and OM wherein there is treatment failure. Several human pathogens, including NTHI, have evolved a novel genetic system, termed the phasevarion (for phase variable regulon), which mediates a rapid and reversible change in the expression of many genes throughout the chromosome. This epigenetic regulation occurs via phase variation of a single gene (modA) that encodes a DNA methyltransferase, and results in two phenotypically distinct subpopulations, ON and OFF. Our preliminary data clearly demonstrated that differences in the gene expression between these subpopulations have a significant affect on in vitro phenotypes known to be critical to the disease course of OM. We further showed that the status of the phasevarion, as well as switching from one status to the other, significantly affects disease severity in a chinchilla model of experimental OM. However, ModA2-regualted gene expression during ascension from the site of colonization, the nasopharynx, to the site of disease, the middle ear is unknown. In Specific Aim 1, we will assess site-specific expression of genes regulated by the ModA2 phasevarion in a model of ascending experimental model that mimics the disease course in children. Studies to determine gene expression within the host during experimental OM are absolutely necessary to fully understand the mechanisms by which the phasevarion contributes to both disease severity and bacterial persistence in various anatomical niches. Additionally, phasevarion regulation occurs through epigenetic methylation and cannot be discerned in silico. In Specific Aim 2, we will define immune cell recruitment, define cytokine expression profiles and identify antibodies developed against each modA2 population as well as a shift in ModA2 state over the course of disease development. A comprehensive understanding of when, where and how the phasevarion regulates expression of virulence factors combined with subsequent host immune responses to these changes in NTHI gene expression is required for the development of optimal disease treatment and prevention strategies. We expect to contribute significantly to this improved understanding of the role of the phasevarion in bacterial-host interactions via successful completion of Specific Aims of this proposal.

项目概要 中耳感染或中耳炎 (OM) 是儿童期最常见的细菌性疾病，可导致 在美国和全球范围内发病率很高。 OM 发作会严重影响孩子的听力 通常情况下。由于对语言的长期影响，这种听力损失备受关注 发展。多种不同的细菌和病毒会导致中耳感染。不可打字 流感嗜血杆菌(NTHI)是慢性 OM、复发性 OM 和其中 OM 的主要细菌病原体 存在治疗失败的情况。包括 NTHI 在内的几种人类病原体已经进化出一种新的遗传系统， 称为phasevarion（相位变量调节器），它介导快速且可逆的变化 许多基因在整个染色体上表达。这种表观遗传调控通过相位变化发生 编码 DNA 甲基转移酶的单个基因 (modA)，并导致两种表型不同的 亚群，ON 和 OFF。我们的初步数据清楚地表明基因的差异 这些亚群之间的表达对已知至关重要的体外表型有显着影响 OM 的病程。我们进一步表明了phasevarion的状态，以及从 一种状态相对于另一种状态，显着影响实验性 OM 龙猫模型中的疾病严重程度。 然而，ModA2 在从定植位点鼻咽上升的过程中调节基因表达， 发病部位，中耳不明。在具体目标 1 中，我们将评估位点特异性表达 在模拟上升实验模型的模型中受 ModA2 相位变异调节的基因 儿童的病程。确定实验 OM 期间宿主内基因表达的研究包括 完全理解相位变化对两者的贡献机制是绝对必要的 疾病的严重程度和各种解剖学环境中的细菌持久性。此外，相位变化调节 通过表观遗传甲基化发生，无法在计算机中识别。在具体目标 2 中，我们将定义 免疫细胞招募，定义细胞因子表达谱并识别针对每种细胞因子开发的抗体 modA2 群体以及 ModA2 状态在疾病发展过程中的转变。全面的 了解相变何时、何地以及如何调节毒力因子的表达 随后宿主对 NTHI 基因表达的这些变化做出免疫反应是 制定最佳的疾病治疗和预防策略。我们期望做出重大贡献 通过成功地提高了对相变在细菌-宿主相互作用中的作用的理解 完成本提案的具体目标。

项目成果

Characterization of the Phase-Variable Autotransporter Lav Reveals a Role in Host Cell Adherence and Biofilm Formation in Nontypeable Haemophilus influenzae.

• DOI: 10.1128/iai.00565-21
• 发表时间: 2022-04-21
• 期刊: Infection and immunity
• 影响因子: 3.1

A Bacterial Epigenetic Switch in Non-typeable Haemophilus influenzae Modifies Host Immune Response During Otitis Media.

• DOI: 10.3389/fcimb.2020.512743
• 发表时间: 2020
• 期刊: Frontiers in cellular and infection microbiology
• 影响因子: 5.7
• 作者: Robledo-Avila FH;Ruiz-Rosado JD;Partida-Sanchez S;Brockman KL
• 通讯作者: Brockman KL

Phase variable acetylation of lipooligosaccharide modifies antibody production and opsonophagocytic killing of non-typeable Haemophilus influenzae.

脂寡糖的相变乙酰化改变了抗体的产生和对非类型流感嗜血杆菌的嗜吞噬细胞杀伤。

• DOI: 10.1016/j.isci.2023.107785
• 发表时间: 2023-10-20
• 期刊: ISCIENCE
• 影响因子: 5.8
• 作者: Wills, Brandon M.;Garai, Preeti;Dickinson, Quinn;Meyer, Jesse G.;Brockman, Kenneth L.
• 通讯作者: Brockman, Kenneth L.