Heme, Iron and Oxidative Stress: Regulation of Iron Homeostasis in H. Influenzae

血红素、铁和氧化应激：流感嗜血杆菌铁稳态的调节

基本信息

批准号：
7737702
负责人：
ROBERT S. MUNSON
金额：
$ 36万
依托单位：
RESEARCH INST NATIONWIDE CHILDREN'S HOSP
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-20 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7737702
关键词：
5 year old Affect Albumins Avidity Bacteremia Bacteria Bioinformatics Biological Bronchitis Cells Child Chronic Chronic Obstructive Airway Disease Clinical Code Complement Complex Data Degradation Pathway Diagnosis Disease Drug Metabolic Detoxication Environment Enzymes Epithelial Cells Facilities and Administrative Costs Gene Expression Gene Expression Profile Gene Expression Regulation Gene Targeting Genes Genetic Transcription Genome Goals Growth Haemophilus influenzae Haptoglobins Heat shock proteins Heme Heme Iron Hemoglobin Hemopexin Hemophilus Homeostasis Homologous Gene Human Hydrogen Peroxide Hydroxyl Radical Individual Infant Infection Iron Lead Link Metabolism Microarray Analysis Modeling Mutagenesis Mutation Nasopharynx Neisseria gonorrhoeae Nontypable Haemophilus influenza Open Reading Frames Organism Otitis Media Oxidative Stress Oxygenases PAWR protein Pathogenicity Pattern Physiological Play Production Proteins Rattus Reaction Reactive Oxygen Species Regulation Regulator Genes Regulon Resistance Respiratory Tract Diseases Role Serotyping Serous otitis media Signal Transduction Sinusitis Site Small RNA Solubility Solutions Source Specificity Surface System Testing Therapeutic Intervention Toxic effect United States Upper respiratory tract Vaccine Design alkalinity base biological adaptation to stress cDNA Arrays cell growth combat design effusion extracellular ferrochelatase heme a improved in vivo insight member mucoid mutant novel novel strategies oxidation pathogen prevent protein expression protoporphyrin IX public health relevance research study response stress protein uptake

项目摘要

DESCRIPTION (provided by applicant): Nontypeable Haemophilus influenzae (NTHi) is a significant human pathogen as it is a major cause of otitis media (OM), sinusitis, exacerbations of chronic obstructive pulmonary disease (COPD) and bronchitis. Illness due to NTHi is thus a major societal burden, and an aggressive approach is needed to determine novel ways of combating diseases caused by NTHi. In all aspects of NTHi disease, the organism moves from being a passive member of the upper respiratory tract flora to an opportunistic pathogen in the site of infection. Although iron and heme uptake systems have been identified in NTHi, little is known about how iron and heme uptake is regulated. Also, NTHi is protected from the damage caused by excess iron or heme that is extremely toxic, primarily through production of toxic reactive oxygen species via the Fenton reaction. The mechanisms involved in this protection are unknown. We have used cDNA microarrays to interrogate the transcriptome of strain 86-028NP, an NTHi strain whose genome we have sequenced. We also have constructed mutants in strain 86-028NP that are deficient in the expression of the oxyR gene as well as the fur (ferric uptake regulator) gene and identified the genes in the OxyR and Fur regulons. We propose to further characterize the response of NTHi strain 86-028NP to oxidative stress. Emphasis will be placed on the interrelationship between oxidative stress and control of iron and heme uptake and usage. The fur regulon will be further characterized. Experiments are proposed to identify and characterize Fur- and oxidative stress- regulated small RNAs. Mutants deficient in the expression of both Fur- and sRNA-regulated genes of unknown or poorly defined function as well as genes encoding proteins involved in resistance to oxidative stress will be constructed and characterized. The NTHi strain 86-028NP heme oxygenase will be identified and characterized. These experiments will lead to an improved understanding of how NTHi regulates its iron and heme metabolism and will provide insight into previously uncharacterized iron-regulated genes, some of which may be involved in heme storage and/or heme degradation. The proposed studies will also provide data on the interplay between the oxidative stress response systems and the Fur system in NTHi thereby increasing our understanding of how NTHi responds to environmental signals and providing us with information that will be useful in the design of new approaches to prevent disease caused by NTHi. PUBLIC HEALTH RELEVANCE: Nontypeable Haemophilus influenzae (NTHi) is a common commensal that colonizes the nasopharynx of over 50% of individuals over 5 years of age and causes a number of respiratory tract diseases, including otitis media, sinusitis, exacerbations of chronic obstructive pulmonary disease, bronchitis and occasionally, invasive disease. The direct and indirect cost of diagnosing and managing otitis media exceeds $5 billion annually in the United States alone. Thus, defining how NTHi regulates the uptake of iron to both avoid potential iron toxicity and minimize oxidative stress will provide insight into how NTHi causes these diseases as well as novel ways to approach eradicating diseases caused by NTHi.

描述（由申请人提供）：不可分型流感嗜血杆菌（NTHi）是一种重要的人类病原体，因为它是中耳炎（OM）、鼻窦炎、慢性阻塞性肺病（COPD）和支气管炎恶化的主要原因。因此，NTHi 引起的疾病是主要的社会负担，需要采取积极的方法来确定对抗 NTHi 引起的疾病的新方法。在 NTHi 疾病的各个方面，生物体从上呼吸道菌群的被动成员转变为感染部位的机会病原体。尽管 NTHi 中已经确定了铁和血红素摄取系统，但对于铁和血红素摄取是如何调节的仍知之甚少。此外，NTHi 还可免受过量铁或血红素造成的损害，这些铁或血红素具有剧毒，主要是通过芬顿反应产生有毒的活性氧。这种保护所涉及的机制尚不清楚。我们使用 cDNA 微阵列来询问菌株 86-028NP 的转录组，这是一种 NTHi 菌株，我们已经对其基因组进行了测序。我们还在菌株 86-028NP 中构建了 oxyR 基因和 Fur（铁吸收调节剂）基因表达缺陷的突变体，并鉴定了 OxyR 和 Fur 调节子中的基因。我们建议进一步表征 NTHi 菌株 86-028NP 对氧化应激的反应。重点将放在氧化应激与铁和血红素摄取和使用控制之间的相互关系。毛皮调节子将被进一步表征。建议进行实验来鉴定和表征毛皮和氧化应激调节的小 RNA。将构建和表征功能未知或定义不明确的 Fur 和 sRNA 调节基因以及编码参与抗氧化应激的蛋白质的基因表达缺陷的突变体。 NTHi 菌株 86-028NP 血红素加氧酶将被鉴定和表征。这些实验将有助于更好地了解 NTHi 如何调节其铁和血红素代谢，并将深入了解以前未表征的铁调节基因，其中一些可能涉及血红素储存和/或血红素降解。拟议的研究还将提供有关 NTHi 中氧化应激反应系统和毛皮系统之间相互作用的数据，从而增加我们对 NTHi 如何响应环境信号的理解，并为我们提供有助于设计预防新方法的信息。 NTHi 引起的疾病。公共卫生相关性：不可分型流感嗜血杆菌 (NTHi) 是一种常见的共生菌，5 岁以上个体的鼻咽部定植有超过 50%，可引起多种呼吸道疾病，包括中耳炎、鼻窦炎、慢性阻塞性肺病恶化、支气管炎，偶尔还有侵袭性疾病。仅在美国，每年诊断和治疗中耳炎的直接和间接费用就超过 50 亿美元。因此，定义 NTHi 如何调节铁的吸收以避免潜在的铁毒性并最大限度地减少氧化应激，将有助于深入了解 NTHi 如何导致这些疾病，以及根除 NTHi 引起的疾病的新方法。